Endovascular aneurysm repair: gender-specific results

OBJECTIVES: The outcome for a wide variety of diseases and treatment methods varies by gender. In an effort to determine whether gender has a role in the outcome of endovascular aortic aneurysm repair, we analyzed data from consecutive patients treated at a single institution over 6 years. METHODS: Over 6 years ending in March 2002, 704 patients underwent endovascular repair of an infrarenal abdominal aortic aneurysm at The Cleveland Clinic. Six hundred six patients (86.1%) were men and 98 patients (13.9%) were women. Preprocedure and postprocedure imaging studies were evaluated to determine the frequency of aneurysm sac shrinkage or growth, defined as diameter change equal to or greater than 5 mm. Presence and type of endoleak was assessed with non-contrast material-enhanced, post-contrast-enhanced, and delayed post-contrast-enhanced computed tomography scans. These and other clinical variables were assessed with the Kaplan-Meier method and the Cox-Mantel log-rank test, and values were expressed as mean +/- SE. RESULTS: Male and female patients were comparable with respect to baseline comorbid conditions. Women, however, were slightly older (76.7 +/- 0.7 years vs 74.4 +/- 0.3 years; P =.009), and had slightly smaller aneurysms (5.2 +/- 0.1 cm vs 5.4 +/- 0.04 cm; P =.033). There were no gender-specific differences in perioperative mortality (men, 1.3%; women, 3.1%; P =.197) or mid-term (24 months) survival (men, 80% +/- 2.6%; women, 78% +/- 8.1%). Similarly, there were no differences at 24 months in risk for graft migration (7.5% +/- 2.0% vs 5.4% +/- 3.2%), need for secondary remedial procedures (24% +/- 2.9% vs 21% +/- 6.3%), conversion to open surgery (3.9% +/- 1.5% vs 3.8% +/-2.7%), or post-repair aneurysm rupture (1.1% +/- 0.9% vs 2.2% +/-2.2%) in male and female patients, respectively. In contrast, risk for graft limb occlusion at 24 months was significantly higher in women than in men (11% +/- 5.2% vs 3.3% +/- 1.1%; P =.022). While frequency of endoleak of any type did not differ among male and female patients, aneurysm sac shrinkage at 24 months was more rapid in women (76% +/- 8.1% vs 57% +/- 3.5%; P =.019). CONCLUSIONS: With the exception of slightly older age and somewhat smaller aneurysm, female patients are similar to male patients undergoing endovascular aneurysm repair. A greater frequency of graft limb occlusion was observed in female patients, but no statistically significant differences were detected in survival, rupture risk, or need for secondary procedures. Moreover, a more rapid rate of aneurysm sac shrinkage was detected in women. These observations suggest that endovascular aneurysm repair should be offered to suitable candidates irrespective of gender.     

Use of cine magnetic resonance angiography in quantifying aneurysm pulsatility associated with endoleak

OBJECTIVE: Persistent aneurysm perfusion or endoleak is associated with pulsatility of abdominal aortic aneurysm (AAA) after endovascular repair. However, the resultant pulsatile change in aneurysm diameter may be difficult to quantify, and therefore its significance is unknown. In this study cine magnetic resonance angiography (MRA) was used to quantify aneurysm wall motion during the cardiac cycle and to correlate it with the presence and type of endoleak. METHODS: Cine MRA was performed in 16 patients undergoing endovascular repair of AAA. A 1.5 T magnet and post-processing with GEMS 4.0 Fiesta computerized video image analysis software were used to calculate maximum aortic diameter during systole and diastole. Changes in aortic diameter were determined from these measurements. Cine MRA was performed on aneurysms before treatment and in patients with and without endoleak after endovascular repair. Type of endoleak was confirmed at angiography in all cases. Four patients had antegrade (type I) endoleak, and eight patients had retrograde (type II) endoleak; no endoleak was present in four patients. Endovascular grafts with stent support throughout the entire length of the graft (Talent) were used in all cases (14 bifurcated grafts, 2 tube grafts). RESULTS: Cine MRA demonstrated significantly greater wall motion and resultant change in aneurysm diameter in patients with type I endoleak compared with patients without endoleak (type I, 2.14 +/- 1.28 mm vs no endoleak, 0.12 +/- 0.09 mm, P =.001). Change in aneurysm diameter in patients with type II endoleak was not significantly greater than in patients with no endoleak (type II, 0.26 +/- 0.21 mm vs no endoleak, 0.12 +/- 0.09 mm, P = NS). Untreated aneurysms demonstrated the greatest change in diameter during the cardiac cycle (3.51 +/- 0.79 mm). CONCLUSION: Cine MRA may be used to accurately quantify AAA wall motion before and after endovascular stent-graft treatment. The extent of change in diameter corresponds to the type of endoleak, with antegrade (type I) endoleak generating greater pulsatile change in diameter than retrograde-collateral (type II) endoleak or no endoleak. Cine MRA may provide a noninvasive means of assessing the success of endovascular treatment of AAA. Further studies will be necessary to confirm the utility and efficacy of cine MRA in postoperative assessment of endovascular aneurysm repair.     

Aneurysm enlargement following endovascular aneurysm repair: AneuRx clinical trial

OBJECTIVE: The purpose of this study was to determine the incidence and significance of aneurysm enlargement, with or without treatment, in relation to the primary end points of rupture, surgical conversion, aneurysm-related death, and survival following endovascular repair. METHOD: Aneurysm (AAA) size changes and clinical outcome of all patients treated from 1997 through 1998 during the Phase II AneuRx multicenter clinical trial of endovascular AAA repair were reviewed. Aneurysm dimensions and the presence or absence of endoleak were determined by an independent core laboratory, with enlargement or shrinkage defined as a diameter change of 5 mm or more compared with baseline. RESULTS: Among 383 patients (89% men, 11% women, age 73 +/- 9 years), with a mean device implant time of 36 +/- 11 months (median = 39 months), aneurysm diameter decreased from 5.7 +/- 1.0 at baseline to 5.2 +/- 1.0 at 3 years (P =.0001). A total of 46 patients (12%) experienced AAA enlargement, 199 patients (52%) had no change in AAA diameter, and 138 patients (36%) had a decrease in AAA diameter of 5 mm or more. Significant risk factors for enlargement included age (enlargement patients were 4 years older on average than patients with aneurysms that decreased in size; P =.002) and the presence of an endoleak (P <.001). Among patients with endoleak at any time, 17% had aneurysm enlargement, whereas only 2% of patients without endoleak had aneurysm enlargement (P <.001). Patients with enlargement were more likely to undergo secondary endovascular procedures and surgical conversions (P <.001). Twenty patients (43%) with enlargement underwent treatment, and 26 patients were untreated. There were two deaths following elective surgical conversion and one death in a patient with untreated enlargement and a type I endoleak. Three aneurysms ruptured: one with enlargement, one with no change, and one with a decrease in aneurysm size; all three aneurysms were larger than 6.5 cm. Kaplan-Meier analysis showed that freedom from rupture at 3 years was 98% with enlargement, 99% with no change, and 99% with decrease in AAA size (log-rank test, not significant). Freedom from AAA death at 3 years was 93% in patients with enlargement, 99% in no increase, and 99% in decrease (P =.005). Survival at 3 years was 86% with increase, 82% with no change, and 93% with decrease (P =.02). CONCLUSIONS: Aneurysm enlargement following endovascular repair was not associated with an increased risk of aneurysm rupture or decrease in patient survival during a 3-year observation period. Aneurysm size rather than enlargement may be a more meaningful predictor of rupture. Close follow-up and a high re-intervention rate (43%) may account for the low risk of rupture in patients with enlargement. The long-term significance of aneurysm enlargement following endovascular repair remains to be determined.     

Diameter of abdominal aortic aneurysm and outcome of endovascular aneurysm repair: does size matter? A report from EUROSTAR

OBJECTIVES: This study was undertaken to determine the effect of the preoperative diameter of abdominal aortic aneurysms on the midterm outcome after endovascular abdominal aneurysm repair (EVAR). METHOD: The data for 4392 patients who had undergone EVAR were analyzed. Patients were enrolled over 6 years to June 2002 in the EUROSTAR database. Outcomes were compared between three groups defined by the preoperative diameter of the aneurysm: group A (n = 1962), 4.0 to 5.4 cm; group B (n = 1528), 5.5 to 6.4 cm; and group C (n = 902), 6.5 cm or larger. Patient characteristics, details of aortoiliac anatomy, operative procedures, old or current device generation, and postoperative complications in the three patient groups were compared. Outcome events included aneurysm-related death, unrelated death, conversion, and post-EVAR rupture of the aneurysm. Life table analysis and log-rank tests were used to compare outcome in the three study groups. Multivariate Cox models were used to determine whether baseline and follow-up variables were independently associated with adverse outcome events. RESULTS: Patients in group C were significantly older than patients in groups A and B (73 years vs 70 and 72 years, respectively; P =.003 - P <.0001 for different group comparisons), and more frequently were at higher operative risk (American Society of Anesthesiologists classification >or=3; 63% vs 48% and 54%; P =.0002-P <.0001). Device-related (type I) endoleaks were more frequently observed at early postoperative arteriography in group C compared with groups A and B (9.9% vs 3.7% and 6.8%; P =.01-P <.0001). Postoperatively systemic complications were more frequently present in group C (17.4% vs 12.0% in group A and 12.6% in group B; P <.0001 and.001). The first-month mortality was approximately twice as high in group C compared with the other groups combined (4.1% vs 2.1%; P <.0001). Late rupture was most frequent in group C. Follow-up results at midterm were less favorable in groups C and B compared with group A (freedom from rupture, 90%, 98%, and 98% at 4 years in groups C, B, and A, respectively; P <.0001 for group C vs groups A and B). Aneurysm-related death was highest in group C (88% freedom at 4 years, compared with 95% in group B and 97% in A; P =.001 and P <.0001, respectively; group B vs A, P =.004). The annual rate of aneurysm-related death in group C was 1% in the first 3 years, but accelerated to 8.0% in the fourth year. Incidence of unrelated death also was higher in groups C and B than in group A (76% and 82% freedom at 4 years vs 87%; P <.0001 for both comparisons). Ratio of aneurysm-related to unrelated death was 23%, 21%, and 50% in groups A, B, and C, respectively. Cox models demonstrated that the correlation between large aneurysms (group C) and all assessed outcome events was independent and highly significant. Older generation devices had an independent association with aneurysm-related and unrelated deaths (P =.02 and P =.04, respectively). However, this correlation was less strong than large aneurysm diameter (P =.0001 and P =.0009, respectively). CONCLUSIONS: The midterm outcome of large aneurysms after EVAR was associated with increased rates of aneurysm-related death, unrelated death, and rupture. Reports of EVAR should stratify their outcomes according to the diameter of the aneurysm. Large aneurysms need a more rigorous post-EVAR surveillance schedule than do smaller aneurysms. In small aneurysms EVAR was associated with excellent outcome. This finding may justify reappraisal of currently accepted management strategies.     

Aneurysm-related death: primary endpoint analysis for comparison of open and endovascular repair

PURPOSE: The purpose of this study was to utilize an objective endpoint analysis of aneurysm treatment, which is based on the primary objective of aneurysm repair, and to apply it to a consecutive series of patients undergoing open and endovascular repair. METHOD: Aneurysm-related death was defined as any death that occurred within 30 days of primary aneurysm treatment (open or endovascular), within 30 days of a secondary aneurysm or graft-related treatment, or any death related to the aneurysm or graft at any time following treatment. We reviewed 417 consecutive patients undergoing elective infrarenal aortic aneurysm repair: 243 patients with open repair and 174 patients with endovascular repair. RESULTS: There was no difference between the groups (open vs endovascular) with regard to mean age +/- standard deviation (73 +/- 8 years vs 74 +/- 8 years) or aneurysm size (64 +/- 2 mm vs 58 +/- 10 mm) (P = not significant [NS]). The 30-day mortality for the primary procedure after open repair was 3.7% (9/243) and after endovascular repair was 0.6% (1/174, P <.05). The 30-day mortality for secondary procedures after open repair was 14% (6/41) compared to 0% after endovascular repair (P <.05). The aneurysm-related death rate was 4.1% (10/243) after open surgery and 0.6% (1/174) after endovascular repair (P <.05). Mean follow-up was 5 months longer following open repair (P <.05). Secondary procedures were performed in 41 patients following open surgery and 27 patients following endovascular repair (P = NS). Secondary procedures following open repair were performed for anastomotic aneurysms (n = 18), graft infection (n = 6), aortoenteric fistula (n = 5), anastomotic hemorrhage (n = 4), lower extremity amputation (n = 4), graft thrombosis (n = 3), and distal revascularization (n = 1). Secondary procedures following endovascular repair consisted of proximal extender cuffs (n = 11), distal extender cuffs (n = 11), limb thrombosis (n = 3), and surgical conversion (n = 2). The magnitude of secondary procedures following open repair was greater with longer operative time 292 +/- 89 minutes vs 129 +/- 33 minutes (P <.0001), longer length of stay 13 +/- 10 days vs 2 +/- 2 days (P <.0001) and greater blood loss 3382 +/- 4278 mL vs 851 +/- 114 mL (P <.0001). CONCLUSIONS: The aneurysm-related death rate combines early and late deaths and should be used as the primary outcome measure to objectively compare the results of open and endovascular repair in the treatment of infrarenal abdominal aortic aneurysms. In our experience, endovascular aneurysm repair reduced the overall aneurysm-related death rate when compared to open repair. Secondary procedures are required after both open and endovascular repair. However, the magnitude, morbidity, and mortality of secondary procedures are reduced significantly with endovascular repair.     

Morphologic changes and outcome following endovascular abdominal aortic aneurysm repair as a function of aneurysm size

HYPOTHESIS: Small infrarenal abdominal aortic aneurysms have a more favorable clinical and morphologic outcome compared with medium and large abdominal aortic aneurysms following endovascular aneurysm repair(EVAR). DESIGN: A prospective clinical series of 206 patients undergoing elective EVAR between 1996 and 2001. SETTING: A tertiary care academic health center. PATIENTS: Patients were grouped according to aneurysm size: small (<50 mm), medium (50-60 mm), and large (>60 mm). INTERVENTIONS: Primary EVAR and secondary procedures to secure fixation of the stent graft and surgical conversions. MAIN OUTCOME MEASURES: Aneurysm diameter, endoleaks, and long-term morphologic changes were analyzed postoperatively with 3-dimensional reconstructions of computed tomographic angiograms. RESULTS: Groups were similar in age, comorbidities, and follow-up (mean +/- SD, 32.1 +/- 11.8 months). There were 30 small aneurysms, 92 medium aneurysms, and 84 large aneurysms, with a mean size of 45.1 +/- 3.7 mm, 53.8 +/- 3.1 mm, and 66.1 +/- 6.8 mm, respectively (P<.01). There was no significant difference in proximal neck or iliac artery diameter among the 3 groups. The proximal aortic neck length (28.1 +/- 11.6 mm [small]; 23.9 +/- 11.3 mm [medium]; and 22.1 +/- 11.6 mm [large]; P<.05) was significantly shorter in large aneurysms. Furthermore, there was a significant increase (6% [small]; 15% [medium]; and 21% [large]; P<.05) in angulated necks in large aneurysms. Following treatment, aneurysm diameter remained stable in most patients (83% [small]; 82% [medium]; and 83% [large]), with a mean decrease of 2.0 +/- 6.5 mm, 2.1 +/- 6.1 mm, and 3.7 +/- 7.7 mm in each group, respectively (P =.45). There was no difference in the incidence of endoleaks, aneurysm contraction, or aneurysm expansion based on preoperative aneurysm diameter. Secondary procedures were performed in 5 (20%) of 25, 9 (5.2%) of 170, and 5 (36%) of 11 aneurysms that contracted, remained stable, or expanded, respectively, following EVAR (P<.05). CONCLUSIONS: There is a 15% increase in neck angulation and a 27% decrease in neck length in large compared with small infrarenal abdominal aortic aneurysms, with no difference in outcome. Aneurysms that are stable following EVAR have a significantly lower incidence of requiring secondary procedures.     

Endovascular repair for abdominal aortic aneurysms: initial experience of an endograft programme

OBJECTIVE: To evaluate early clinical results of elective endovascular repair of abdominal aortic aneurysms during the initial phase of an aortic endograft programme and to compare them with conventional open surgery. METHODS: Between July 1999 and September 2001, all patients with infrarenal abdominal aortic aneurysms undergoing elective repair were studied. The results of endovascular repair were compared with those of conventional repair. RESULTS: Twenty-seven endovascular repairs (24 men and three women; mean age, 74 yr) and 25 conventional repairs (19 men and six women; mean age, 73 yr) for infrarenal abdominal aortic aneurysms were evaluated. The aneurysm diameters in the two groups were similar (mean, 6.1 cm in the endovascular repair group and 6.6 cm in the conventional repair group). The comorbidities of the two groups were also comparable. The duration of operation was longer in the endograft group (249 +/- 86 min vs. 206 +/- 56 min), while the blood loss was significantly less (600 +/- 486 mL vs. 1074 +/- 1220 mL). The length of stay in the Intensive Care Unit (ICU) and the overall duration of hospitalization was also significantly less in the endograft group (1 +/- 1 d vs. 3 +/- 2 d in ICU; 9 +/- 5 d vs. 13 +/- 6 d of hospitalization). There was one hospital death in each group (4%), and the complications were similar between the two groups. During a mean follow-up period of 11.6 +/- 7.5 months, there was no rupture or open conversion in the endograft group. CONCLUSIONS: In the initial phase of the aortic endograft programme, the mortality and morbidity were acceptable and comparable to that of open surgery.     

The prevalence and natural history of aortic aneurysms in heart and abdominal organ transplant patients

OBJECTIVE: The purpose of this study was to document the prevalence and clinical features of aortic aneurysms in heart and abdominal transplant patients. METHODS: We undertook a retrospective review of 1557 patients who had heart, liver, or kidney transplantation between January 1, 1987, and December 31, 2000. Aortic aneurysms were identified by computed tomographic scan, ultrasound scan, or at the time of surgery for rupture. An aortic diameter of 3.5 cm was used as the threshold for the definition of aneurysmal disease. We compared dichotomous variables with Fisher's exact test and continuous variables with the Wilcoxon rank-sum test. RESULTS: There were 296 heart, 450 liver, and 811 kidney transplants performed on adult patients during the study period. We identified 18 transplant patients who had an aortic aneurysm (13 heart, three liver, two kidney). Seven patients (41%) had rupture of the aortic aneurysm, and five of these patients died. There were no deaths from causes other than aortic aneurysm rupture. The rate of aneurysm rupture was 22.5% per year. Eight patients had the aortic aneurysm repaired electively with no deaths and no hospital stay greater than 15 days. The mean aortic aneurysm size at rupture was 6.02 +/- 0.86 cm, and the smallest aneurysm that ruptured was 5.1 cm. The pretransplant rate of aortic aneurysm expansion was 0.46 cm/y, but this increased to 1.00 cm/y after transplantation (P =.08). The rate of aortic aneurysm expansion among heart transplant patients and abdominal transplant patients was the same (P =.51). The prevalence of aortic aneurysm was 4.1% in cardiac transplant patients and 0.4% in abdominal transplant patients. Earlier in our series (1987 to 1996), 11% of the cardiac transplant patients were screened for aortic aneurysms, and the prevalence rate of diagnosis was 3.0%. Screening of cardiac transplant candidates became more frequent in 1997 (87% screened), with an associated increase in the aortic aneurysm prevalence rate to 5.8% in the patients who were screened. CONCLUSION: Aortic aneurysms in cardiac and abdominal transplant patients have an aggressive natural history with high expansion and rupture rates. Screening transplant patients for aortic aneurysms will increase detection and facilitate elective repair, which is generally well tolerated. These findings support programs for early detection and elective treatment of aortic aneurysms in organ transplant patients, particularly those having heart transplants.     

Endovascular aneurysm repair at 5 years: does aneurysm diameter predict outcome?

OBJECTIVE: The appropriate size threshold for endovascular repair of small abdominal aortic aneurysms (AAA) is unclear. We studied the outcome of endovascular aneurysm repair (EVAR) as a function of preoperative aneurysm diameter to determine the relationship between aneurysm size and long-term outcome of endovascular repair. METHODS: We reviewed the results of 923 patients treated in a prospective, multicenter clinical trial of EVAR. Small aneurysms were defined according to two size thresholds of 5.5 cm and 5.0 cm. Two-way analysis was used to compare patients with small aneurysms (<5.5 cm, n = 441) to patients with large aneurysms (> or =5.5 cm, n = 482). An ordered three-way analysis was used to compare patients with small AAA (<5.0 cm, n = 145), medium AAA (5.0 to 5.9 cm, n = 461), and large AAA (> or =6.0 cm, n = 317). The primary outcome measures of rupture, AAA-related death, surgical conversion, secondary intervention, and survival were compared using Kaplan-Meier estimates at 5 years. RESULTS: Median aneurysm size was 5.5 cm. The two-way comparison showed that 5 years after EVAR, patients with small aneurysms (<5.5 cm) had a lower AAA-related death rate (1% vs 6%, P = .006), a higher survival rate (69% vs 57%, P = .0002), and a lower secondary intervention rate (25% vs 32%, P = .03) than patients with large aneurysms (> or =5.5 cm). Three-way analysis revealed that patients with small AAAs (<5.0 cm) were younger (P < .0001) and were more likely to have a family history of aneurysm (P < .05), prior coronary intervention (P = .003), and peripheral occlusive disease (P = .008) than patients with larger AAAs. Patients with smaller AAAs also had more favorable aortic neck anatomy (P < .004). Patients with large AAAs were older (P < .0001), had higher operative risk (P = .01), and were more likely to have chronic obstructive pulmonary disease (P = .005), obesity (P = .03), and congestive heart failure (P = .004). At 5 years, patients with small AAAs had better outcomes, with 100% freedom from rupture vs 97% for medium AAAs and 93% for large AAAs (P = .02), 99% freedom from AAA-related death vs 97% for medium AAAs and 92% for large AAAs (P = .02) and 98% freedom from conversion vs 92% for medium AAAs and 89% for large AAAs (P = .01). Survival was significantly improved in small (69%) and medium AAAs (68%) compared to large AAAs (51%, P < .0001). Multivariate Cox proportional hazards modeling revealed that aneurysm size was a significant independent predictor of rupture (P = .04; hazard ratio [HR], 2.195), AAA-related death (P = .03; HR, 2.007), surgical conversion (P = .007; HR, 1.827), and survival (P = .001; HR, 1.351). There were no significant differences in secondary intervention, endoleak, or migration rates between small, medium, and large AAAs. CONCLUSIONS: Preoperative aneurysm size is an important determinant of long-term outcome following endovascular repair. Patients with small AAAs (<5.0 cm) are more favorable candidates for EVAR and have the best long-term outcomes, with 99% freedom from AAA death at 5 years. Patients with large AAAs (> or =6.0 cm) have shorter life expectancy and have a higher risk of rupture, surgical conversion, and aneurysm-related death following EVAR compared to patients with smaller aneurysms. Nonetheless, 92% of patients with large AAAs are protected from AAA-related death at 5 years. Patients with AAAs of intermediate size (5 to 6 cm) represent most of the patients treated with EVAR and have a 97% freedom from AAA-related death at 5 years.     

Aortic necks of ruptured abdominal aneurysms dilate more than asymptomatic aneurysms after endovascular repair

BACKGROUND: Endovascular repair of abdominal aortic aneurysm (AAA) is increasingly used. We evaluated if a difference exists in the rate of change of the aortic neck diameter between non-ruptured and ruptured AAAs after endovascular aneurysm repair (EVAR). METHODS: Details of patients undergoing elective (group I) and emergency (group II) EVAR using Talent stents between October 1999 and September 2005 were reviewed. Top neck diameters were prospectively recorded on the hospital database from computed tomography scans preoperatively and at 1, 3, 12, and 24 months postoperatively. The aortic neck diameter rate of change was calculated for each group. RESULTS: Endovascular repair was performed on 110 elective and 41 emergency patients, of which 100 (80 male) elective and 29 (26 male) emergency patients were included in this analysis. Mean age was similar in each group. Stents were oversized by 20.9% +/- 13.6% in group I and by 24.7% +/- 16.3% in group II (P = .37). The preoperative mean proximal aortic neck was larger in group II (25.0 +/- 3.3 mm vs 23.5 +/- 2.8 mm; P = .029). The growth rate of the top neck diameter was significantly greater at 12 months (1.48 +/- 2.4 mm/year vs 3.89 +/- 6.24 mm/year; P = .04) and 24 months (.99 +/- 1.1 mm/year vs 2.61 +/- 3.3 mm/year; P = .04) in group II than in group I. A decreasing sac size was found in 68.2% of patients whose neck dilated. The complication rate was similar in each group. CONCLUSION: Aneurysm necks in patients with ruptured aneurysms are larger and dilate at a greater rate than those with nonruptured aneurysms. The accelerated rate of expansion in some patients must be borne in mind during follow-up and in secondary endovascular interventions and conversion to open surgery.     

The impact of walking impairment,cardiovascular risk factors,and comorbidity on quality of life in patients with intermittent claudication

PURPOSE: This study assessed the cardiovascular disease, perioperative results, and survival after surgical abdominal aortic aneurysm repair in young patients (< or = 50 years) compared with randomly selected older patients who also underwent abdominal aortic aneurysm repair. METHODS: We reviewed hospital records to identify young and randomly selected control patients (3 for each young patient, > or = 65 years, matched for year of operation) with degenerative (atherosclerotic) abdominal aortic aneurysms undergoing repair between Jan 1, 1988, and Mar 31, 2000. Patients with congenital aneurysms, pseudoaneurysms, aortic dissections, post-coarctation dilations, aortic infection, arteritis, or aneurysms isolated to the thoracic aorta were excluded. Mortality data and cause of death were obtained from medical records and the National Death Index RESULTS: Among 1168 patients who underwent abdominal aortic aneurysm repairs, 19 young patients (1.6%) and 57 control patients were identified. The mean age was 48.4 years in the young group and 72.2 years in the control group. There were no differences in sex or race between the two groups. When comparing existing cardiovascular disease between the groups, there were no differences in the incidence of earlier coronary revascularization (26% vs 16%) or non-cardiac vascular surgery (5% vs 9%), but aneurysms were more commonly symptomatic in young patients (53% vs 21%; P <.01). Aneurysmal disease was limited to the infrarenal aorta in similar proportions of patients (89% vs 88%). No statistically significant differences were seen in the incidence of perioperative deaths (16% young vs 9% control; P =.40) or postoperative complications (37% young vs 26% control; P =.38). The estimated survival rate of the young group was not different from that of the control group (3-year survival rate, 73% vs 69%; P =.32) or the entire cohort of patients (older than 50 years; n = 1101) who underwent repair of abdominal aortic aneurysms during the study period (3-year survival 73% vs 75%; P =.63) CONCLUSION: After abdominal aortic aneurysm repair, young patients had perioperative results and follow-up mortality rates similar to those of control patients. Cardiovascular disease was the predominant cause of death after abdominal aortic aneurysm repair in the young patients. When compared with an age older than 50 years at the time of abdominal aortic aneurysm repair, young age alone was not associated with increased survival.     

Endovascular repair or surveillance of patients with small AAA.

OBJECTIVE: To compare the outcome of patients with small abdominal aortic aneurysms (AAA) treated in a prospective trial of endovascular aneurysm repair (EVAR) to patients randomized to the surveillance arm of the UK Small Aneurysm Trial. METHOD: All patients with small AAA (< or = 5.5 cm diameter) treated with a stent graft (EVARsmall) in the multicenter AneuRx clinical trial from 1997 to 1999 were reviewed with follow up through 2003. A subgroup of patients (EVARmatch) who met the age (60-76 years) and aneurysm size (4.0-5.5 cm diameter) inclusion criteria of the UK Small Aneurysm Trial were compared to the published results of the surveillance patient cohort (UKsurveil) of the UK Small Aneurysm Trial (NEJM 346:1445, 2002). Endpoints of comparison were aneurysm rupture, fatal aneurysm rupture, operative mortality, aneurysm related death and overall mortality. The total patient years of follow-up for EVAR patients was 1369 years and for UK patients was 3048 years. Statistical comparisons of EVARmatch and UKsurveil patients were made for rates per 100 patient years of follow up (/100 years) to adjust for differences in follow-up time. RESULTS: The EVARsmall group of 478 patients comprised 40% of the total number of patients treated during the course of the AneuRx clinical trial. The EVARmatch group of 312 patients excluded 151 patients for age < 60 or > 76 years and 15 patients for AAA diameter < 4 cm. With the exception of age, there were no significant differences between EVARsmall and EVARmatch in pre-operative factors or post-operative outcomes. In comparison to the UKsurveil group of 527 patients, the EVARmatch group was slightly older (70 +/- 4 vs. 69 +/- 4 years, p = 0.009), had larger aneurysms (5.0 +/- 0.3 vs. 4.6 +/- 0.4 cm, p < 0.001), fewer women (7 vs. 18%, p < 0.001), and had a higher prevalence of diabetes and hypertension and a lower prevalence of smoking at baseline. Ruptures occurred in 1.6% of EVARmatch patients and 5.1% of UKsurveil patients; this difference was not significant when adjusted for the difference in length of follow up. Fatal aneurysm rupture rate, adjusted for follow up time, was four times higher in UKsurveil (0.8/100 patient years) than in EVARmatch (0.2/100 patient years, p < 0.001); this difference remained significant when adjusted for difference in gender mix. Elective operative mortality rate was significantly lower in EVARmatch (1.9%) than in UKsurveil (5.9%, p < 0.01). Aneurysm-related death rate was two times higher in UKsurveil (1.6/100 patient years) than in EVARmatch (0.8/100 patient years, p = 0.03). All-cause mortality rate was significantly higher in UKsurveil (8.3/100 patient years) than in EVARmatch (6.4/100 patient years, p = 0.02). CONCLUSIONS: It appears that endovascular repair of small abdominal aortic aneurysms (4.0-5.5 cm) significantly reduces the risk of fatal aneurysm rupture and aneurysm-related death and improves overall patient survival compared to an ultrasound surveillance strategy with selective open surgical repair.     

Incidence and risk factors of late rupture, conversion, and death after endovascular repair of infrarenal aortic aneurysms: the EUROSTAR experience. European Collaborators on Stent/graft techniques for aortic aneurysm repair

OBJECTIVE: The EUROSTAR (European Collaborators on Stent/graft techniques for aortic aneurysm repair) Registry was established in 1996 to collect data on the outcome of treatment of patients with infrarenal aortic aneurysms with endovascular repair. To date, 88 European centers of vascular surgery have contributed. The purpose of the study was to evaluate the results of this treatment in the medium term (up to 4 years) according to the analysis of "hard" or primary end points of rupture, late conversion, and death. PATIENTS AND METHODS: Patients with aortic aneurysms suitable for endovascular aneurysm repair were notified to the EUROSTAR Data Registry Centre before treatment to eliminate bias due to selective reporting. The following information was collected on all patients: (1) demographic details and the anatomic characteristics of their aneurysms, (2) details of the endovascular device used, (3) complications encountered during the procedure and the immediate outcome, (4) results of contrast enhanced computed tomographic imaging at 3, 6, 12, and 18 months after operation and at yearly intervals thereafter, and (5) all adverse events. Life table analysis was performed to determine the cumulative rates of (1) death from all causes, (2) rupture, and (3) late conversion to open repair. Risk factors for rupture and late conversion were identified through regression analysis. RESULTS: By March 2000, 2464 patients had been registered, and their mean duration of follow-up was 12.19 months (SD, 12.3 months). There were 14 patients with confirmed rupture of their aneurysms. The cumulative rate (risk) of rupture was approximately 1% per year. Emergency surgery was undertaken in 12 (86%) patients, of whom five (41.6%) survived. Two patients who were not treated surgically also died, which resulted in an overall death rate of 64.5% (9/14) of the patients. Significant risk factors for rupture were proximal type I endoleak (P =.001), midgraft (type III) endoleak (P =.001), graft migration (P =.001), and postoperative kinking of the endograft (P =.001). Forty-one patients underwent late conversion to open repair with a perioperative mortality rate of 24.4% (10/41). The cumulative rate (risk) of late conversion was approximately 2.1% per year. Risk factors (indications) for late conversion were proximal type I endoleak (P =. 001), midgraft (type III) endoleak (P =.001), type II endoleak (P =. 003), graft migration (P =.001), graft kinking (P =.001), and distal type I endoleak (P =.001). CONCLUSIONS: Endovascular repair of infrarenal aortic aneurysms with the first- and second-generation devices that predominated in this study was associated with a risk of late failure, according to an analysis of observed hard end points of 3% per year. Action taken to address the risk factors identified by the study may improve results in the future.     

Endograft migration one to four years after endovascular abdominal aortic aneurysm repair with the AneuRx device: a cautionary note

BACKGROUND: Positional stability of the endograft is essential for long-term durability after endovascular abdominal aortic aneurysm repair (EAR). However, the cumulative risk of delayed endograft migration has been sparsely reported. METHOD: A total of 91 patients studied underwent EAR with the AneuRx endograft with a minimum 1 year from implantation. Data from a prospective database were assessed for proximal endograft migration, defined as > or = 5 mm change from the initial endograft position. Multiple anatomic characteristics were also examined. Sixty-nine patients were alive, with complete follow-up at 1 year, with a mean time from implantation of 33.2 +/- 1.1 months. Data are mean +/- SEM. RESULTS: Endograft migration occurred in 15 patients, giving a cumulative event rate of 7.2% (5/69) at 1 year, 20.4% (10/49) at 2 years, 42.1% (8/19) at 3 years, and 66.7% (2/3) at 4 years post-EAR (P =.01). Although the initial aortic neck diameter did not differ between the groups (21.5 +/- 0.6 mm vs 21.8 +/- 0.3 mm, P =.61), significant (P <.05), late aortic neck enlargement was seen in patients with migration (25.0 +/- 1.6 mm, 26.2 +/- 1.2 mm, and 27.0 +/- 1.0 mm at 1,2, and 3 years, respectively) but not in nonmigrators. Regression analysis demonstrated a statistically significant (P <.05) correlation between endograft oversizing and late aortic neck dilation. Overall migration risk was 29.2% in patients oversized >20% and 18.6% in patients oversized < or = 20%. Aortic neck angulation (23.4 +/- 6.6 degrees vs 23.5 +/- 3.3 degrees, P =.99), aortic neck length (25.9 +/- 2.5 mm vs 27.0 +/- 1.6 mm, P =.74), initial endograft/aortic neck overlap (18.6 +/- 2.6 mm vs 19.4 +/- 1.4 mm, P =.80) and size of abdominal aortic aneurysm (55.5 +/- 1.5 mm vs 54.9 +/- 1.4 mm, P =.84) were similar between migrators and nonmigrators, respectively. Secondary endovascular treatment with aortic cuffs was required in five patients with device migration. CONCLUSIONS: Device migration after EAR with the AneuRx endograft occurred with significant frequency, the incidence of which increased with the length of follow-up. Late aortic neck dilation was significantly associated with migration. Oversizing of the endograft of >20% may accelerate this late aortic neck dilation. However, the etiologies of endograft migration were likely multifactorial, as the majority (8/15) of patients experiencing migration were oversized <20%. Although endovascular repair of these migrations is usually possible, the long-term durability of these secondary procedures is unknown. Careful surveillance for this endograft failure mode must be an essential component of post-EAR follow-up.     

Prediction of rupture risk in abdominal aortic aneurysm during observation: wall stress versus diameter

OBJECTIVES: We previously showed that peak abdominal aortic aneurysm (AAA) wall stress calculated for aneurysms in vivo is higher at rupture than at elective repair. The purpose of this study was to analyze rupture risk over time in patients under observation. METHODS: Computed tomography (CT) scans were analyzed for patients with AAA when observation was planned for at least 6 months. AAA wall stress distribution was computationally determined in vivo with CT data, three-dimensional computer modeling, finite element analysis (nonlinear hyperelastic model depicting aneurysm wall behavior), and blood pressure during observation. RESULTS: Analysis included 103 patients and 159 CT scans (mean follow-up, 14 +/- 2 months per CT). Forty-two patients were observed with no intervention for at least 1 year (mean follow-up, 28 +/- 3 months). Elective repair was performed within 1 year in 39 patients, and emergent repair was performed in 22 patients (mean, 6 +/- 1 month after CT) for rupture (n = 14) or acute severe pain. Significant differences were found for initial diameter (observation, 4.9 +/-.1 cm; elective repair, 5.9 +/-.1 cm; emergent repair, 6.1 +/-.2 cm; P <.0001) and initial peak wall stress (38 +/- 1 N/cm(2), 42 +/- 2 n/cm(2), 58 +/- 4 N/cm(2), respectively; P <.0001), but peak wall stress appeared to better differentiate patients who later required emergent repair (elective vs emergent repair: diameter, 3% difference, P =.5; stress, 38% difference, P <.0001). Receiver operating characteristic (ROC) curves for predicting rupture were better for peak wall stress (sensitivity, 94%; specificity,81%; accuracy, 85% [with 44 N/cm(2) threshold]) than for diameter (81%, 70%, 73%, respectively [with optimal 5.5 cm threshold). With proportional hazards analysis, peak wall stress (relative risk, 25x) and gender (relative risk, 3x) were the only significant independent predictors of rupture. CONCLUSIONS: For AAAs under observation, peak AAA wall stress seems superior to diameter in differentiating patients who will experience catastrophic outcome. Elevated wall stress associated with rupture is not simply an acute event near the time of rupture.     

Endovascular repair of abdominal aortic aneurysms: device-specific outcome

OBJECTIVES: Endovascular repair of abdominal aortic aneurysms, while advantageous because of its minimally invasive nature, falls short of achieving the long-term durability of traditional open surgical repair. Problems such as device migration, continued sac pressurization from endoleak, and graft limb thrombosis culminate in a high rate of secondary procedures and failure to protect against aneurysm rupture. While prior studies hint at a correlation between these postprocedural events and specific device design, a single comparative analysis that correlates device attributes with clinical outcome has not been performed. METHODS: Over 6 years ending in 2002, 703 patients underwent endovascular treatment of infrarenal abdominal aortic aneurysms. During this time, five devices were used, ie, Ancure, AneuRx, Excluder, Talent, and Zenith, and six device-specific groups were analyzed; the Zenith group was subdivided into those placed as part of the multicenter trial (Zenith-MCT) and those under a sponsor-investigator investigational device exemption trial (Zenith-SIT). Results were assessed with the Kaplan-Meier method for censored data, and the log-rank test was used to ascertain differences between device groups. RESULTS: While overall survival was diminished in the Zenith-SIT group (P =.046), risk for aneurysm-related death was similar in all groups (P =.336), averaging 2% or less at 12 months. Among the total cohort of patients, freedom from rupture was 98.7% +/- 0.9% at 24 months, without demonstrable differences between groups (P =.533). There were no statistically significant differences in rate of secondary procedures, conversion to open repair, or migration. There were, however, significant differences in risk for graft limb occlusion and rate of endoleak between groups. Limb occlusion occurred most often with Ancure devices (11% +/- 4.6% at 12 months, P =.009). Endoleak of any type was most common with Excluder devices (64% +/- 11% at 12 months, P =.003), a finding directly related to increased frequency of type II leaks in that group (58% +/- 11% at 12 months, P =.001). While there were no differences in frequency of type I or type III endoleak, a trend toward increased risk for microleak was observed with AneuRx devices (4.0% +/- 1.3%, P =.054), and more modular separations were observed with Zenith devices (3.5% +/- 2.3%, P =.032). Shrinkage at 12 months correlated with frequency of endoleak in the device groups, and was most common in the two Zenith groups (54% +/- 7.3% in the Zenith-MCT group and 56% +/- 7.8% in the Zenith-SIT group) and the Talent group (52% +/- 9.7%) and was least in the Excluder group (15% +/- 7.9% at 12 months, P <.001). By contrast, sac growth occurred most often in the Zenith-SIT group (13% +/- 4.5% at 12 months, P =.034), possibly as a result of the challenging aortoiliac anatomy frequently present in these patients. CONCLUSIONS: There are significant differences in frequency of limb occlusion and endoleak between groups with different endovascular devices. Knowledge of these and other differences is instructional in development of next-generation endovascular devices, incorporating design features linked to satisfactory outcome while abandoning those associated with device failure.     

Lessons learned in adopting endovascular techniques for treating abdominal aortic aneurysm

HYPOTHESIS: Endovascular exclusion of abdominal aortic and common iliac aneurysms can be performed safely, and in the short term represents a feasible alternative to traditional, open aneurysm repair. PATIENTS AND METHODS: Forty-one patients were treated with endovascular grafts for 39 abdominal aortic and 2 common iliac artery aneurysms. RESULTS: All devices were successfully deployed. The size of the abdominal aortic aneurysms varied from 4.9 to 11.9 cm (average, 6.13 cm). The median procedure time was 195 minutes. There was one iliac artery rupture, which required celiotomy for repair. The hospital stay varied from 2 to 39 days (average, 6.7 days). The perioperative mortality rate was 2.4%. Sixteen patients (39%) had groin wound complications. Ten patients (24%) had evidence of contrast (endoleak) within the aneurysm sac on completion of the procedure. There were no obvious direct leaks from either the point of proximal or distal fixation. Seven of these endoleaks have resolved spontaneously. Two patients required additional procedures in the postoperative period to treat endoleak. The final patient has evidence of persistent endoleak on 3-month surveillance computed tomography scan. Major late problems occurred in 3 patients. CONCLUSION: Patients with large abdominal aortic aneurysms and considerable cardiac comorbidity can safely undergo endovascular aneurysm repair. Femoral groin wound complications resulting in prolonged hospitalization remain the major cause of perioperative morbidity. In contradistinction to open aneurysm repair, long-term surveillance is essential to detect migration of the device and identify flow within the residual aneurysm sac-complications that could lead to aneurysm rupture following endovascular repair.     

Effect of improved endograft design on outcome of endovascular aneurysm repair

OBJECTIVE: This study was undertaken to identify factors that lead to improvements in the results of endovascular aneurysm repair, with particular focus on new endograft design. METHODS: We analyzed data for patients enrolled in the European Collaborators on Stent Graft Techniques for Abdominal Aortic Aneurysm Repair (EUROSTAR) registry, and compared those for endografts now withdrawn from the market with those for endografts currently in use. Patients in whom a variety of endograft types were used in small numbers were excluded. Postoperative and long-term outcomes were initially compared with univariate analyses, and subsequently multivariate tests were used to adjust for baseline differences between the 2 groups. The main outcome measures were freedom from a variety of secondary interventions, aneurysm rupture, and death. RESULTS: Some 1224 patients received "withdrawn" endografts, and 2768 patients received "current" endografts. The 2 groups were generally similar, but patients with current devices were more often men, significantly older, more frequently unfit for open surgery, and had larger aneurysms with wider necks. Of no surprise, current endografts were also more often used by experienced (>60 previous cases) surgical teams (44% vs 20%; P <.0001). Thirty-day clinical outcomes were comparable in the 2 groups, although patients with withdrawn devices were less likely to have type II endoleak (9.2% vs 5.5%; P <.0001), and those with current devices had a shorter mean hospital stay (5.4 vs 6.8 days; P <.0001). At 3 years more patients with current devices were free from secondary transfemoral intervention (88.4% vs 76%; P <.0001) and conversion to open repair (95.4% vs 93.4%; P =.007). Aneurysm-related mortality at 3 years, defined as death due to aneurysm rupture or within 30 days of a secondary intervention, was also less frequent with current endografts (2.7% vs 4.4%; P =.02). Aneurysm rupture at 3 years was infrequent (0.8% vs 1.8%; P =.07). At multivariate analysis the use of current devices was a protective factor against late conversion to open repair (hazard ratio, 0.49; 95% confidence interval, 0.28-0.86; P =.014) and aneurysm-related death (hazard ratio, 0.51, 95% confidence interval, 0.34-0.75; P =.0008). Larger aneurysm or neck diameter and shorter neck length were also associated with late conversion to open repair; larger aneurysm diameter, older age, and unfitness for open surgery were predictive of aneurysm-related death. CONCLUSION: Modern endograft design has improved the results of endovascular aneurysm repair.     

Impact of endovascular repair on open aortic aneurysm surgical training.

PURPOSE: The purpose of this study was to determine the impact of an endovascular stent-graft program on vascular training in open aortic aneurysm surgery. METHODS: The institutional and vascular surgery fellow experience in aortic aneurysm repair during a 6-year period was reviewed. The 3-year period before introduction of endovascular repair was compared with the 3-year period after introduction of endovascular repair. All patients undergoing abdominal aortic aneurysm (AAA) or thoracoabdominal aortic aneurysm repairs were entered prospectively into a vascular registry and retrospectively analyzed to evaluate the changing patterns in aortic aneurysm treatment and surgical training. RESULTS: Between July 1994 and June 2000, a total of 588 patients with AAA or thoracoabdominal aneurysms were treated at Stanford University Medical Center. There were 296 (50%) open infrarenal AAA repairs, 87 (15%) suprarenal AAA repairs, 47 (8%) thoracoabdominal aneurysm repairs, and 153 (26%) endovascular stent-grafts. The total number of aneurysms repaired per year by vascular fellows before the endovascular program was 71.3 +/- 4.9 (range, 68-77) and increased to 124.7 +/- 35.6 (range, 91-162) after introduction of endovascular repair (P <.05). This increase was primarily caused by the addition of endovascular stent-graft repairs by vascular fellows (51.0 +/- 29.0/year [range, 23-81]). There was no change in the number of open infrarenal aortic aneurysm repairs per year, 53.0 +/- 6.6 (range, 48-56) before endovascular repair versus 47.0 +/- 1.7 (range, 46-49) after (P = not significant). There was a significant increase in the number of suprarenal AAA repairs per year by vascular fellows, 10.0 +/- 1.0 (range, 9-11) before endovascular repair compared with 19.0 +/- 6.5 (range, 13-26) after (P <.05). There was no change in the number of thoracoabdominal aneurysm repairs per year between the two groups, 8.0 +/- 3.0 (range, 4-11) before endovascular repair compared with 7.6 +/- 2.3 (range, 5-9) after. CONCLUSIONS: Introduction of an endovascular aneurysm stent-graft program significantly increased the total number of aneurysms treated. Although the number of open aneurysm repairs has remained the same, the complexity of the open aneurysm experience has increased significantly for vascular fellows in training.     

Does the presence of an iliac aneurysm affect outcome of endoluminal AAA repair? An analysis of 336 cases.

OBJECTIVE: To determine whether the presence of an iliac aneurysm compromises outcome of endovascular exclusion of AAA and to ascertain the fate of the iliac aneurysmal sac. PATIENTS AND METHODS: Between April 1997 and March 2001, data on 336 consecutive patients undergoing endovascular repair for AAA were entered in a prospective database. Suitability for endovascular repair was assessed by preoperative contrast-enhanced computed tomography. A maximum common iliac artery (CIA) diameter > or = 20 mm was defined as iliac aneurysm. Patients with and without iliac aneurysms were compared to early (immediate conversion or perioperative death) and late failure (increase in aneurysm diameter or persisting graft-related endoleak, or late AAA rupture or conversion). RESULTS: Fifty-nine patients (18%) had iliac aneurysms, 19 were bilateral, for a total of 78 aneurysmal iliac arteries (median diameter 23 mm; range 20-50 mm). A distal seal was achieved by landing in 33 external iliac arteries, in 20 ectatic CIAs, and in 25 normal CIAs. Operating time differed significantly between patients with and without CIA aneurysms (153 +/- 71 vs 123 +/- 55 min, p = 0.0001), whereas no statistically significant differences were found with respect to early and late failure (2% vs 3%, p = 0.5 and 14% vs 8%, p = 0.11, respectively). There were no cases of buttock or colon necrosis. At a median follow-up of 14 months (range 0-46; i.q.r. 7-27 months) common iliac diameter decreased > or = 2 mm in 49 cases, remained stable in 25, and increased > or = 2 mm in 3. CONCLUSION: The presence of iliac aneurysm rendered endoluminal AAA repair more complex but did not affect feasibility and long-term outcome of the procedure. In our experience internal iliac exclusion was never associated with significant morbidity. These data may be useful when considering endovascular repair in high-risk patients with challenging anatomy.