Analysis of medical risk factors and outcomes in patients undergoing open versus endovascular abdominal aortic aneurysm repair

OBJECTIVE: The emergence of endovascular repair (ER) for infrarenal abdominal aortic aneurysm (AAA) has provided surgeons with a new technique that should ideally improve patient outcomes. To more accurately characterize the advantages of ER versus traditional/open AAA repair (TOR), we compared the preoperative medical risk factors (PMRFs) and perioperative outcomes (PO) of those patients undergoing elective treatment of infrarenal AAA with ER and TOR over a recent 18-month period at our center. METHODS: Through our institutional vascular surgery patient registry, all patients undergoing aortic aneurysm repair of any type between December 1999 and June 2001 were identified. Only those patients undergoing elective infrarenal AAA repair were analyzed. Hospital records were examined for all patients, and PMRF and PO were assessed via Society for Vascular Surgery/International Society for Cardiovascular Surgery reporting guidelines. Student t, chi(2), Fisher exact, or Wilcoxon rank sum tests were applied where appropriate to determine differences among PMRF and PO according to method of aneurysm repair. RESULTS: During the 18-month study period, a total of 199 aortic aneurysms were repaired at our institution. Ninety-nine elective infrarenal AAA repairs made up the study cohort (ER, n = 33; TOR, n = 66). When examined by method of aneurysm repair, no differences existed in demographics or AAA size. Patients undergoing ER had a significantly greater degree of preoperative pulmonary comorbidity than patients undergoing TOR (P <.001). However, no differences existed in terms of American Society of Anesthesiologists classification or cardiac (P =.52), cerebrovascular (P =.44), diabetic (P =.51), hypertensive (P =.90), hyperlipidemia (P =.91) or renal (P =.23) comorbidities between the two groups. Perioperative morbidity and mortality rates were also not significantly different by method of repair. ER was associated with shorter operative time, intensive care unit stay, and overall hospital length of stay (P <.0001). However, subsequent operative procedures related to the AAA repair were performed more frequently after ER (TOR = 1.5% versus ER = 15.2%; P = 0.015). CONCLUSION: These results suggest that ER offers improvements in hospital convalescent and operating room times but no beneficial impact on overall morbidity and mortality rates when similar PMRFs exist, especially when used at medical centers where low morbidity and mortality rates are already established for TOR. Other centers performing ER should undertake such an analysis to assess its impact on their patients.     

Contemporary results of juxtarenal aneurysm repair

OBJECTIVE: The increasing use of aortic endografts predictably will add to the complexity of open abdominal aortic aneurysm (AAA) repair and, therefore, the proportion of surgically treated infrarenal AAAs that are juxtarenal in location (JRA) will grow. This study reviews a single-center experience with JRAs. METHODS: Between June 1994 and December 2000, 138 patients underwent elective repair of a JRA, comprising 16.1% of 859 consecutive asymptomatic and intact symptomatic nonruptured infrarenal AAAs repaired over the same period. All patients with JRA needed proximal suprarenal clamping (SRC) or supravisceral (SVC) clamping. Patient demographics, selected risk factors, and operative details were recorded. Univariate analyses of selected risk factors for an adverse perioperative event were assessed, and multivariate analyses were performed with linear and logistic regression with backwards selection. RESULTS: SRC was used in 95 patients (69%), and 43 patients (31%) underwent SVC. The mortality rate was 5.1% (7/138) for JRA repair, and 2.8% (20/720) for infrarenal AAA repair (P =.03). The mortality rate was significantly greater for those patients who received SVC compared with SRC (11.6% versus 2.1%; P =.02). Multivariate analysis identified SVC position as the only independent predictor of mortality (odds ratio [OR], 6.1; 95% CI, 1.1 to 32.9; P =.035). Transient renal insufficiency occurred in 39 patients (28.3%), but only eight patients (5.8%) needed dialysis. Patients who had SVC had a significantly greater rate of renal insufficiency than those who received SRC (41.9% versus 22.1%; P =.02). Multivariate analysis showed SVC position (OR, 3.3; 95% CI, 1.4 to 7.8; P =.008), diabetes (OR, 3.7; 95% CI, 1.1 to 12.9; P =.04), and preoperative renal insufficiency (OR, 5.8; 95% CI, 2.2 to 15.4; P <.001) were independent predictors of postoperative renal insufficiency. Renal ischemia during proximal clamping cannot alone explain renal complications because clamp time was shorter in patients with SVC (24.9 +/- 2.4 minutes versus 32.2 +/- 1.5 minutes; P =.009). CONCLUSION: JRA repair can be accomplished with a low mortality rate, but a more proximal clamp position may adversely affect outcome in these patients. Postoperative renal insufficiency is related to diabetes, preoperative renal insufficiency, and SVC position. These results suggest SRC is safer than SVC for proximal aortic clamp control of JRAs. Although clamp level must be tailored to patient anatomy, outcome may be improved if the clamp level can be kept distal to the superior mesenteric artery origin.     

Impact of chronic obstructive pulmonary disease on elective and emergency abdominal aortic aneurysm repair

OBJECTIVE: Chronic obstructive pulmonary disease (COPD) is associated with abdominal aortic aneurysm (AAA) expansion and is considered by some to be a relative contraindication to conventional aortic surgery. This study was undertaken to determine if COPD increases operative death, morbidity, intensive care unit (ICU) length of stay (LOS), and hospital LOS, after AAA repair. METHODS: Data from national administrative records supplemented with laboratory data previously obtained for a system-wide study were analyzed in a retrospective review of 1053 consecutive patients (264 with and 789 without COPD) undergoing operation for intact or ruptured AAAs in Veterans Administration Hospitals from 1997 to 1998. Bivariate comparisons and multivariate regression were used to evaluate the impact of COPD on the number of days of ventilation, ICU LOS, total hospital LOS, and death, while controlling for other known risk factors, including acute myocardial infarction, renal failure, and age. RESULTS: The mortality rate in elective aneurysm patients did not differ (P =.99) between patients with (3.7%) or without COPD (3.7%). However, elective AAA repair was associated with longer hospital LOS (14.4 vs 12.3 days, P =.01), longer ICU LOS (6.5 vs 5.4 days, P =.01), and a higher incidence of requiring 96 hours or more ventilation (6.9% vs 3.6%, P =.02) in patients with COPD. Ruptured AAA affected 4.9% of patients and was strongly associated with COPD (P =.02); however, COPD did not result in a statistically significant increase in death (P =.25). CONCLUSIONS: Although COPD does not appear to increase operative death, it is associated with an increased risk of rupture. Elective repair of AAA should not be deferred in patients with COPD despite their higher LOSs and need for postoperative ventilation.     

Peroperative factors influencing the outcome of elective abdominal aorta aneurysm repair.

PURPOSE: To identify perioperative variables which may influence mortality of elective abdominal aneurysm repair (AAA). METHOD: prospective study of patients undergoing elective AAA repair between 1986 and 1997. RESULTS: Four hundred and seventy patients (438 men, 32 females) with a mean age of 69.4+/-13 years and aneurysms with a diameter of 60+/-3 mm were operated on with a 1-month mortality rate of 5.3%. Multivariate analysis identified the following independent risk factors for mortality: age >70 (p<0.0001), a past history of myocardial infarction (p<0.0001), preoperative renal insufficiency (p<0.0001), reoperation (p<0.0001), colonic necrosis (p<0.0001), and severe postoperative medical complications (p<0.0001). CONCLUSION: Intra- and postoperative events affect the outcome of AAA repair, independently of preoperative factors, and should be described when presenting the results of AAA repair.     

Abdominal aortic aneurysm repair in patients with preoperative renal failure

The purpose of this study was to determine the effect of preoperative renal failure on the outcome of patients undergoing infrarenal abdominal aortic aneurysm (AAA) repair. Of 251 patients undergoing AAA repair from 1977 to 1984, 10% had evidence of preoperative chronic renal failure. These patients were classified according to their preoperative serum creatinine values; group I had preoperative creatinine levels of 2 to 4 mg/dl, group II had creatinine levels greater than 4 mg/dl but no history of hemodialysis, and group III consisted of patients on chronic hemodialysis before operation. One of 16 patients in group I developed transient high-output renal failure postoperatively. Four of the six patients in group II (67%) developed significant postoperative deterioration of renal function and required acute hemodialysis. Of the four patients in group III maintained on chronic hemodialysis preoperatively, one died of sepsis from an ischemic colon. This experience suggests that patients with mild renal dysfunction (serum creatine value less than 4 mg/dl) can undergo elective AAA repair without additional morbidity. Patients on hemodialysis before operation can also safely undergo surgical repair of their AAAs electively if dialyzed the day before operation. Patients with severe renal dysfunction (serum creatinine greater than 4 mg/dl) who are not on hemodialysis should be considered for dialysis preoperatively in an attempt to reduce the high incidence of serious postoperative renal functional deterioration and subsequent morbidity.     

Analysis of renal function after aneurysm repair with a device using suprarenal fixation (Zenith AAA Endovascular Graft) in contrast to open surgical repair

PURPOSE: This study was undertaken to assess the effect on renal function of open surgery and endovascular abdominal aortic aneurysm (AAA) repair with suprarenal fixation with the Zenith device. METHODS: Data for 279 patients with similar preoperative comorbid conditions were prospectively analyzed after AAA repair. One hundred ninety-nine patients underwent endografting with the Zenith AAA Endovascular Graft, which incorporates suprarenal fixation (Zenith standard risk group, ZSR), and 80 patients underwent open surgery (standard surgical risk group, SSR). Endovascular repair was also performed in 100 patients considered poor candidates for open repair (Zenith high risk group, ZHR). Serum creatinine concentration (SCr) and anatomic defects were assessed before the procedure, before discharge, and at 1, 6, 12, and 24 months in all patients who underwent endovascular repair, and before the procedure and at 1 and 12 months in patients who underwent open surgical repair (only SCr was measured before discharge). Renal function was also analyzed, with a creatinine clearance calculation (Cockcraft-Gault). Renal insufficiency was defined as an increase in SCr greater than 30% from a preoperative baseline value, any SCr concentration in excess of 2.0 mg/dL, or any need for dialysis. Cumulative renal infarction and arterial occlusion rates were calculated with computed tomographic, ultrasonographic, and angiographic data, and reported as cumulative values. RESULTS: Despite the initially superior renal function in the ZSR group at the pre-discharge evaluation (P =.01), there were no differences at 12 months with respect to rise in SCr greater than 30% (ZSR, 16%, vs SSR, 12%; P =.67), SCr rise greater than 2.0 mg/dL (ZSR, 2.5%, vs SSR, 3.4%; P =.66), incidence of renal artery occlusion (ZSR, 1%, vs SSR, 1.4%; P >.99), or infarction (ZSR, 1.5%, vs SSR, 1.4%; P >.99). Only one patient in each group required hemodialysis. Of note, both groups of patients demonstrated a reduction in creatinine clearance over 12 months, which then stabilized or improved by 24 months for ZSR patients. CONCLUSIONS: Renal dysfunction occurs in a subset of patients regardless of type of repair (open or endovascular with suprarenal fixation). The cause of renal dysfunction after open or endovascular repair with a suprarenal stent is probably multifactorial. The observed dysfunction occurs in a small number of patients, and the effect in the endovascular group (no data for the surgical group at 24 months) appears to be transient. The initial dysfunction, apparent in both groups over 12 months of follow-up, stabilizes or improves at 12 to 24 months.     

Durability of benefits of endovascular versus conventional abdominal aortic aneurysm repair

PURPOSE: Endovascular abdominal aortic aneurysm (AAA) repair is reported to result in less initial patient morbidity and a shorter hospital length of stay (LOS) when compared with conventional AAA repair. We sought to examine the durability of this result during the intermediate follow-up interval. METHODS: The records of all admissions for all patients who underwent AAA repair during a 26-month interval were reviewed. RESULTS: Three hundred thirty-seven (337) patients underwent procedures to repair AAAs (163 open and 174 endovascular). Endovascular procedures were performed with a variety of devices (Talent, 108; Ancure, 36; AneuRx, 26; Zenith, 2; and Cordis, 2) and configurations (141 bifurcated and 33 aortomonoiliac). The mean follow-up period was 10.6 months (endovascular repair) and 12.3 months (open repair). LOS did not significantly vary by device (P =.24 to P =.92) or configuration (P =.24). The initial median LOS for procedures was significantly shorter (P =.009) for endovascular repairs (5 days) than for open procedures (8 days). However, the patients who underwent endovascular repair were more likely to be readmitted during the follow-up interval when compared with patients who underwent open procedure. The readmission-free survival rate after AAA repair at 12 months was 95% for patients for open AAA repair versus 71% for patients for endovascular repair (P <.001). If the total hospital days were compared, including the initial and all subsequent AAA-related admissions, there was no significant difference for mean LOS for patients who underwent endovascular versus open AAA procedures (11 days versus 13.6 days; P =.21). The patients for endovascular AAA repair most commonly needed readmission for treatment of endoleak (n = 31), wound infection (n = 12), and graft limb thrombosis (n = 9). Although women had similar LOS to men for endovascular repair (P =.44), they had longer initial LOS for open AAA repair (15 versus 10 days; P =.03). After endovascular repair, women were more likely than men to be readmitted by 12 months (51% versus 71% readmission-free survival rate; P =.03) and they had longer LOS on readmission (13.2 versus 5.2 days; P =.006). No gender differences were identified for patients after open AAA repair regarding readmission-free survival rate (P =.09) or LOS on readmission (P =.98). CONCLUSION: Although initial LOS was shorter for the patients who underwent endovascular as compared with conventional AAA repair, this advantage was lost during the follow-up interval because of frequent readmission for the treatment of procedure-related complications, chiefly endoleak. These readmissions frequently involved the performance of additional invasive procedures. Gender differences existed regarding LOS and the likelihood of complications after open and endovascular AAA repair.     

Endovascular abdominal aortic aneurysm repair with general versus local anesthesia: a comparison of cardiopulmonary morbidity and mortality rates

PURPOSE: The purpose of this study was to compare the cardiopulmonary morbidity and mortality rates after endovascular abdominal aortic aneurysm (EAAA) repair with local anesthesia (LA) with intravenous sedation versus general anesthesia (GA). METHODS: Data from patients who underwent elective infrarenal EAAA repair between June 1996 and October 2000 were retrospectively reviewed. Patients with two or more Eagle clinical cardiac risk factors were considered to be at increased risk for a major postoperative cardiac event. Univariate and multivariate analyses for major cardiac and pulmonary morbidity and mortality rates were analyzed with respect to anesthetic type (GA versus LA), age, size of aneurysm, mean number of Eagle risk factors, and presence of two or more cardiac risk factors. RESULTS: Two hundred twenty-nine patients underwent EAAA repair. The GA (158 patients) and LA (71 patients) groups were significantly different with respect to mean age (73 versus 76 years; P =.01) and mean number of cardiac risk factors per patient (1.2 versus 1.6; P =.002). No difference was seen in the overall cardiopulmonary complication rate (13% for GA and 19% for LA; P =.3), pulmonary complication rate (3.8% for GA and 7% for LA; P =.3), or cardiopulmonary mortality rate (3.2% for GA and 2.8% for LA; P =.9). The major cardiac event rate was higher in patients with two or more Eagle risk factors (22%) versus those patients with one or less Eagle risk factors (3.4%; P <.001), irrespective of anesthetic type. In analysis of patients with one or less Eagle risk factors, no difference was seen in the major cardiac event rate by anesthetic type (3% for GA and 5% for LA; P =.6). Also, no difference was seen in major cardiac events in patients with two or more Eagle risk factors by anesthetic type (24% for GA and 22% for LA). On multivariate analysis, the mean number of Eagle risk factors per patient (P <.0001) and the presence of two or more Eagle risk factors were associated with major cardiac and cardiopulmonary complications, whereas age, size of AAA, and anesthetic type were not. CONCLUSION: No difference exists in overall cardiac and pulmonary morbidity and mortality rates after EAAA repair in comparison of GA and LA. The presence of two or more preoperative cardiac risk factors significantly increases the risk of a major postoperative cardiac event.     

Propensity score analysis in observational studies: outcomes after abdominal aortic aneurysm repair

OBJECTIVE: Large databases composed of well-designed prospectively collected cohort data provide an opportunity to examine and compare healthcare treatments in actual clinical practice settings. Because the analysis of these data often leads to a retrospective cohort design, it is essential to adequately adjust for lack of balance in patient characteristics when making treatment comparisons. We used matched propensity scoring in a cohort of patients undergoing elective aneurysm repair as an illustrative example of this important statistical method that adjusts for baseline characteristics and selection bias by matching covariables. METHODS: By using prospectively collected clinical data from the National Surgical Quality Improvement Program of the Department of Veterans Affairs, we studied 30-day mortality, 1-year survival, and postoperative complications in 1904 patients who underwent elective AAA repair (endovascular aneurysm repair [EVAR], n=717 (37.7%); open aneurysm repair, n=1187 [62.3%]) at 123 Veterans Health Administration's hospitals between May 1, 2001, and September 30, 2003. In bivariate analysis, patient characteristics and operative and hospital variables were associated with both type of surgery and outcomes of surgery. Therefore, the predicted probability of receiving EVAR was tabulated for all patients by using multiple logistic regression to control for 32 independent demographic and clinical characteristics and then stratified into 5 groups. Patients were matched within strata based on similar levels of the independent measures (a propensity score technique), creating a pseudo-randomized control design. The proportion of patients with the morbidity and mortality outcomes was then compared between the EVAR and open procedures within strata to control for selection. RESULTS: Patients undergoing EVAR had significantly lower unadjusted 30-day (3.1% versus 5.6%, P=.01) and 1-year mortality (8.7% versus 12.1%, P=.018) than patients undergoing open repair. By using propensity scoring, the proportions of EVAR patients experiencing 30-day mortality were equal or less than patients undergoing open procedures for all levels of probability and decreased as the probability of EVAR increased. Furthermore, propensity scoring also showed that patients having EVAR had lower 1-year mortality and experienced fewer perioperative complications. CONCLUSIONS: We used a propensity score approach to examine outcomes after elective AAA repair to statistically control for many factors affecting both treatment selection and outcome. Patients who underwent elective EVAR had substantially lower perioperative mortality and morbidity rates compared with patients having open repair, which was not explained solely by patient selection in an observational dataset.     

Epidural analgesia in patients with chronic obstructive pulmonary disease undergoing transperitoneal abdominal aortic aneurysmorraphy--a multi-institutional analysis

INTRODUCTION: Patients with chronic obstructive pulmonary disease (COPD) are more likely to develop pulmonary morbidity following major abdominal surgery. The purpose of this study was to examine the utility of epidural analgesia in patients with COPD who underwent elective transperitoneal abdominal aortic aneurysm (AAA) repair. METHODS: During a 7-year period, all patients diagnosed with COPD undergoing elective AAA repair (n=425) from three hospitals were reviewed. Inclusion criteria were an FEV(1)/FVC ratio <75% and/or a PaCO(2)>45 mmHg. Clinical outcomes were compared between those who received epidural analgesia (epidural group) and those who did not (control group). Primary endpoints measured were duration of intubation, ICU stay, hospital days, and pulmonary complications. RESULTS: Strict inclusion criteria were met by 131 patients, which included 86 patients in the epidural group and 45 patients in the control group. When comparing the epidural vs. control group, the mean AAA size was 6.3+/-0.9 cm vs. 6.0+/-1.5 cm (NS), FEV(1) was 57.2+/-24.7% vs. 49.0+/-10.3% (NS), and the mean FEV(1)/FVC ratio was 52.0+/-11.4% vs. 50.6+/-6.7% (NS), respectively. The epidural group had a significantly lower incidence of post-operative ventilator dependency and ICU stay (p<0.05), as well as a decreased trend in pulmonary complications when compared to the control group. The overall hospital stay remained similar between the two groups. The relative risk of developing a pulmonary complication in the absence of epidural analgesia was 2.3. CONCLUSIONS: Perioperative epidural analgesia is beneficial in patients with COPD undergoing AAA repair by reducing both the post-operative ventilator duration and ICU stay. Epidural analgesia should be considered in all COPD patients undergoing elective transperitoneal AAA repair.     

Relationship of proximal fixation to postoperative renal dysfunction in patients with normal serum creatinine concentration

OBJECTIVES: This study was performed to determine whether there is deterioration in renal function during follow-up in patients who have undergone endovascular aneurysm repair (EVAR), as recommended by the device manufacturers; to determine whether suprarenal fixation correlates with impairment of renal function; and to explore the potential implication of life-long surveillance of renal function with contrast-enhanced computed tomography. METHODS: One hundred forty-six consecutive patients underwent EVAR at our institution. Data from 113 of these patients who were free from preoperative renal insufficiency or postoperative renal disease were analyzed. Fifty-three patients received infrarenal (IR) fixation devices, and 60 patients received suprarenal (SR) fixation devices. All SR fixation devices were placed under investigational device exemption protocols. The average follow-up was 688 days. Sixty-five consecutive patients who had undergone open repair of an abdominal aortic aneurysm (AAA) served as the control group. RESULTS: Preoperative creatinine concentration, intraoperative blood loss, contrast volume, and number of contrast-enhanced procedures were not significantly different between the IR and SR groups. Two renal artery occlusions (1 SR, 1 IR; P=NS) were identified, and 8 renal infarcts (5 SR, 3 IR; P=NS). There was an increase in mean creatinine concentration in the open AAA, IR, and SR fixation groups at each time point in the analysis. Mean elevation in creatinine concentration at 12, 24, and 36 months was 0.10, 0.10, and 0.04 mg/dL, respectively, for open AAA repair; 0.20, 0.21, and 0.28 mg/dL for IR fixation; and 0.15, 0.21, and 0.12 mg/dL for SR fixation. At life table analysis, renal impairment at 36 months was seen in 36% +/- 9% of patients in the IR group, 25% +/- % of patients in the SR group, and 19% +/- 6% of patients in the open AAA group (P=.04 for IR fixation vs open AAA repair). CONCLUSIONS: A decrease in kidney function is seen after EVAR, regardless of fixation level, that is independent of renal disease and renal arterial occlusion. In patients with normal renal function the site of proximal fixation does not affect postoperative creatinine concentration. The decrease in renal function is likely related to the repetitive administration of contrast agent.     

Preoperative risk factors for 30-day mortality after elective surgery for vascular disease in Department of Veterans Affairs hospitals: is race important?

PURPOSE: Racial variation in health care outcomes is an important topic. Risk-adjustment models have not been developed for elective abdominal aortic aneurysm repair (AAA), lower extremity bypass revascularization (LEB), or lower extremity amputation (AMP). Earlier studies examining racial variation in mortality and morbidity from AAA, LEB, or AMP were limited to administrative data. This study determined risk factors for mortality after surgery for vascular disease and determined whether race is an important risk factor. METHODS: Data in this prospective observational study were obtained from the Department of Veterans Affairs (VA) National Surgical Quality Improvement Program. Detailed demographic and clinical data were collected prospectively from patients' medical records by trained nurse reviewers. Eligible patients were those 18 years and older who underwent elective AAA, LEB, or AMP at one of 44 VA medical centers performing both vascular and cardiac surgery (phase I; October 1991 to December 1993) and at one of these 44 or 79 additional VA medical centers performing vascular but not cardiac surgery (phase II; January 1994 to August 1995). The independent association of several preoperative factors with the 30-day postoperative mortality rate was examined with stepwise logistic regression analysis for AAA, LEB, and AMP. Models were developed in the combined 44 VA medical centers and validated in the 79 VA medical centers. The independent association of race with the 30-day postoperative mortality rate was examined after controlling for important preoperative risk factors for each operation. RESULTS: More than 10,000 surgical operations were examined, and 5, 3, and 10 independent preoperative predictors of 30-day mortality rate were identified for AAA, LEB, and AMP, respectively. The observed mortality rate for patients undergoing AAA was higher (7.2% vs 3.2%; P =.02) in African American patients than in white patients in the 44 VA medical centers, although the differences were not significant in LEB and AMP or at the additional 79 hospitals. After important preoperative risk factors were controlled, there was no difference in 30-day mortality rates between African American patients and white patients. CONCLUSION: We identified several important preoperative risk factors for 30-day mortality rate in three vascular operations. From the results of this study, race was determined not to be an independent predictor of mortality.     

Results of elective abdominal aortic aneurysm repair in the 1990s: A population-based analysis of 2335 cases

OBJECTIVE: The safety and efficacy of conventional abdominal aortic aneurysm (AAA) repair are undergoing increased examination in parallel with the development of less invasive repair methods. Because most published studies of elective AAA repair report operations performed in tertiary referral institutions and thus may not reflect the outcome in the surgical community at large, the current population-based study was undertaken to document the results obtained across a broad spectrum of clinical practice in a defined geographic area and to examine the factors that influence the outcomes. METHODS: The Maryland Health Services Cost Review Commission database was used to identify all the elective AAA repairs that were performed in all the nonfederal acute care hospitals in the state from 1990 to 1995. RESULTS: Elective AAA repair was performed on 2335 patients (mean age, 70.4 years) in 46 of the 52 (88%) nonfederal acute care hospitals in the state, including seven high-volume (>100 cases), nine moderate-volume (50 to 99 cases), and 30 low-volume (<50 cases) institutions. The in-hospital mortality rate was 3.5% and increased significantly with advancing age: less than 65 years, 2.2%; 65 to 69 years, 2.5%; 70 to 79 years, 3.5%; and more than 80 years, 7.3% (P =.002). Mortality rates were higher for women (4.5% vs 3.2%; P =.17), for blacks (6.7% vs 3.2%; P =.046), and for patients with renal failure (11.8% vs 3. 4%; P =.11) but not for patients with hypertension, diabetes, heart disease, and pulmonary disease. The operative mortality rate was inversely correlated with hospital volume (4.3% in low-volume hospitals, 4.2% in moderate-volume hospitals, and 2.5% in high-volume hospitals; P =.08), although no differences were noted in the mean ages or comorbidity levels of patients who underwent operations in these three hospital populations. The operative mortality rate was inversely correlated with the experience of the individual surgeon: one case, 9.9%; two to nine cases, 4.9%; 10 to 49 cases, 2.8%; 50 to 99 cases, 2.9%; and more than 100 cases, 3.8% (P =.01). Multivariate analysis results identified patient age (P =. 002), low hospital volume (P =.039), and very low surgeon volume (P =.01) as independent predictors of operative mortality. The mean length of stay and mean hospital charges were 10.6 days and $17,589 and decreased with increasing surgeon volume: one case, 22.7 days/$32,800; two to nine cases, 10.6 days/$18,509; 10 to 49 cases, 10.0 days/$16,611; 50 to 99 cases, 10.9 days/$17,843; and more than 100 cases, 9.6 days/$16,682 (P <.0001/P <.0001). CONCLUSION: Elective AAA repair is a safe procedure in contemporary practice in Maryland. Operative risk is increased among the elderly and when operations are performed by surgeons with very low volumes or in low-volume hospitals. Hospital lengths of stay were shorter and charges were lower when elective AAA repair was performed by surgeons with higher volumes.     

Payer status is related to differences in access and outcomes of abdominal aortic aneurysm repair in the United States

BACKGROUND: The hypothesis of this study was that differences exist among patients with private insurance compared with patients with Medicaid or no insurance, regarding access to the timely treatment of abdominal aortic aneurysms (AAAs) and the outcomes of AAA repair. METHODS: The study comprised 5363 patients aged less than 65 years (mean age, 59 years) with a diagnostic code for intact or ruptured AAA and a procedure code for AAA repair in the National Inpatient Sample for 1995 to 2000. Dependent variables included ruptured AAA, intact AAA, and in-hospital postoperative mortality rates. Independent variables included payer status, median income, race, gender, age, and comorbid disease. Risk-adjusted analyses were performed with the use of binary logistic regression. RESULTS: AAA rupture was most likely (P <.001) to affect patients with no insurance (36%) or Medicaid (18%), compared with patients with private insurance (13%). After an adjustment for case-mix had been made, data showed that patients without insurance had an increased risk of rupture compared with patients with private insurance (odds ratio, 2.3; 95% CI, 1.5-3.5; P <.001). Operative mortality rates after elective AAA repair were greater (P =.04) for patients with no insurance (2.6%) or Medicaid (2.7%), compared with patients with private insurance (1.2%). Similarly, operative mortality rates for AAA repair after rupture were greater (P =.001) in patients without insurance (45.3%) or Medicaid (31.3%), compared with patients with private insurance (26.2%). CONCLUSIONS: Uninsured patients more often seek treatment of ruptured AAAs compared with patients with private insurance. Operative mortality rates in uninsured patients are greater for elective and emergent AAA repair. These data support the tenet that payer status is associated with mortality rates after AAA repair.     

Perioperative outcomes after open and endovascular repair of intact abdominal aortic aneurysms in the United States during 2001

OBJECTIVE: Small patient numbers, mixed data from clinical trials, and longitudinal series representing institutional learning curves have characterized previous studies of early outcomes after endovascular abdominal aortic aneurysm (AAA) repair. We compared the perioperative outcomes of endovascular and open surgical AAA repair in an unselected sample of patients in a single calendar year using a national administrative database. METHODS: The 2001 National Inpatient Sample database was retrospectively reviewed. This database represents 20% of all-payer stratified sample of non-federal US hospitals. Patients older than 49 years were identified by primary diagnostic codes (International Classification of Disease, ninth revision [ICD-9], 441.4, intact, nonruptured AAA) and procedure codes (ICD-9 38.44 for open, 39.71 for endovascular repair). Patient demographic data (age, sex), comorbid conditions (ICD-9 coded), inpatient complications (ICD-9 coded), length of stay, final discharge disposition (home vs institution vs death), and hospital charges were examined with univariate and multivariate analyses. RESULTS: In calendar year 2001, 7172 patients underwent either open (64%) or endovascular (36%) repair of intact, nonruptured AAAs. Despite comparable rates of preoperative comorbid conditions and a greater proportion of octogenarians (23% vs 16%%; P =.0001), morbidity (18% vs 29%; P =.0001) and mortality (1.3% vs 3.8%; P =.0001) were significantly lower for endovascular repair than for open repair. The median length of stay (2 vs 7 days; P =.0001) and the rate of discharge to an institutional facility versus home (6% vs 14%; P =.0001) were also much lower in the endovascular group than in the open repair group. At multivariate analysis, open AAA repair and age older than 80 years were strong independent predictors (P =.0001 for all) for death (open repair: odds ratio [OR], 3.3; 95% confidence interval [CI], 2.3-4.9; age: OR, 14.2; 95% CI, 3.5-58.1), complications (open repair: OR, 1.9; 95% CI, 1.7-2.1; age: OR, 1.9; 95% CI, 1.5-2.5), and not being discharged to home (open repair: OR, 3.4; 95% CI, 2.9-4.1; age: OR, 12.0; 95% CI, 7.0-20.4). Mean hospital charges were significantly greater (difference, $3337; P =.0009) for endovascular repair than for open repair. Extrapolated to the total number of endovascular AAA repairs performed during the single 2001 calendar year, this resulted in a staggering $50.3 million in additional hospital charges. CONCLUSIONS: Endovascular repair of intact AAAs results in a significantly lower number of complications and deaths, shorter hospital stay, and improved likelihood of discharge to home, even in older patients, when compared with open surgical repair. These impressive gains in clinical outcome, however, are achieved at similarly impressive increases in health care costs.     

Quality of life before and after endovascular and retroperitoneal abdominal aortic aneurysm repair

PURPOSE: This study was undertaken to evaluate changes in quality of life and to compare conventional outcomes in patients undergoing endovascular and open retroperitoneal abdominal aortic aneurysm (AAA) repair. METHODS: Between October 2000 and May 2003, 129 patients underwent elective AAA repair, endovascular repair in 22 patients and open retroperitoneal repair in 107 patients. The Short-Form Health Survey, 12 items (SF-12) was administered preoperatively and at 3 weeks, 4 months, and 1 year after discharge. Quality of life, hospital and intensive care unit stay, perioperative complications, discharge disposition, readmission, and hospital cost were statistically evaluated. RESULTS: For the total group, significant differences were observed for both Physical Component Summary scores (P<.001) and Mental Component Summary scores (P=.001) between time points. There were no significant differences for either Component Summary score between open and endovascular procedures for any time period. Number of weeks required to return to baseline functional status was similar after either open or endovascular repair (7.22 vs 5.47 weeks, respectively; P=.09). Mean hospital and intensive care unit stay was 4.4 and 1 days, respectively, for open repair versus 1.9 and 0 days, respectively, for endovascular repair (P<.0001). No significant difference between groups was observed in terms of perioperative complications, discharge disposition, or hospital readmission (P> or =.54). Mean total hospital cost for endovascular repair was 1.60 times that for open repair (mean difference, $11,662; P<.0001; 95% confidence interval, $17,799-$5525). CONCLUSIONS: Hospital stay is significantly shorter after endovascular AAA repair. However, hospital cost is almost twice that for open retroperitoneal repair. Perioperative complications, discharge disposition, and hospital readmission are not statistically different between the two groups. Effect on health-related quality of life is similar after either open retroperitoneal or endovascular AAA repair.     

腹主动脉瘤患者术后近期死亡和严重并发症

目的了解肾动脉下腹主动脉瘤患者术后近期病死率和并发症发生率,并分析其原因. 方法选择自1988年1月～200 0年12月,在我院行手术治疗的肾动脉下腹主动脉瘤186例,统计术后近期病死率和并发症发生率,分析术前心、肺、肾功能,年龄和手术因素与严重并发症和死亡的关系. 结果择期手术术后近期病死率5.0%,动脉瘤破裂急诊手术57.1 %.择期手术术后近期严重并发症发生率18.4%,其中心血管并发症10.6%,呼吸道并发症1 1.2%,急性肾功能衰竭2.8%,脑血管意外1.1%,肝功能损害1.1%.心血管并发症与术前冠心病明显相关(χ2=19.737,P＜0.01)而与高血压无关(χ2=1.870,P ＞0.05).术前肺功能异常、吸烟史和血氧分压＜80 mmHg与肺部感染有关(χ2=4. 051、5.885和5.162,P＜0.05)而与成人呼吸窘迫综合征无关(χ2=0.127、0 .916和1.067,P＞0.05).术前肾功能状况与急性肾功能衰竭无关(χ2=0.404 ,P＞0.05).70岁以上或手术时间超过5 h,术后严重并发症(χ2=16.119和10 .163,P＜0.01)和死亡(χ2=7.045和12.145,P＜0.01)的发生率明显增加. 结论多系统器官功能衰竭是导致腹主动脉瘤术后近期死亡的主要原因.术后严重并发症以心肺疾病居多.术前心、肺功能,年龄和手术因素与术后严重并发症和死亡密切相关.     

Renal insufficiency and altered postoperative risk in carotid endarterectomy

PURPOSE: Higher complication rates have been reported in patients with renal insufficiency (RI) undergoing peripheral vascular surgery. Little attention has been paid specifically to carotid endarterectomy (CEA) in patients with RI where the risk/benefit considerations are very sensitive to small increases in postoperative complications. METHODS: One thousand one consecutive CEAs performed since 1990 were reviewed from our vascular registry, and 73 CEAs on patients with RI were identified. For comparison, two groups were established: group I (n = 928), normal renal function (creatinine level, <1.5 mg/dL); and group II (n = 73), RI (creatinine level, >/=1.5 mg/dL). RESULTS: Differences in the nonfatal stroke rates and combined stroke and death rates were statistically significant (P <.02) between the groups: group I (1. 08% and 1.18%) and group II (5.56% and 6.94%) respectively. Both groups were similar in regard to operative indications. In addition with the comparison of group I to group II, there was a statistically significant increase in hematoma rate, 1.61% versus 12. 5% ( P <.001), total cardiac morbidity, 1.72% versus 6.94% (P =.003), and total complications, 6.24% versus 36.1% (P =.001). Multivariate analysis demonstrated pre-existing RI to be the only significant predictor for perioperative stroke and hematoma. CONCLUSION: Patients with preoperative RI are at a higher, but not prohibitive, risk for stroke and death after CEA than patients with normal renal function. They are also at risk for hematoma formation, cardiac morbidity, and overall complications. Care in selection of these patients for CEA must be emphasized.     

Glomerular filtration rate after left renal vein division and reconstruction during infrarenal aortic aneurysm repair

OBJECTIVES: The study assessed the effect on postoperative renal function of left renal vein (LRV) division and reconstruction by direct reanastomosis or graft interposition during infrarenal abdominal aortic aneurysm (AAA) repair. METHODS: Between January 2001 and March 2006, 1189 patients underwent elective open repair of infrarenal AAAs. LRV division was performed in 15 (1.3%) and its reconstruction in all but one (LRV group), where the LRV was occluded. Patients' glomerular filtration rates (GFRs) were retrospectively estimated through postoperative day 4 by using the Cockcroft-Gault equation and compared with the GFRs of 56 controls undergoing AAA repair without LRV division (control group) randomly identified from a prospectively compiled database in a 4:1 ratio. Post hoc 1:1 case-matched analysis was also performed. Statistical analyses were performed as appropriate. RESULTS: Comparison of demographics and risk factors revealed no statistically significant differences between the two groups with the exception of the following: AAAs were larger in LRV group (71.4 +/- 17.1 mm vs 56.0 +/- 14.6 mm; P = .003) and preoperative GFR was lower in LRV group (65.3 +/- 19.0 mL/min/1.73 m(2) vs 82.8 +/- 22.3 mL/min/1.73 m(2); P = .009). Postoperatively, the trend of GFR with time did not differ between groups (P = .33). The variation of GFR at day 4 after surgery compared with preoperative values was not different either (5.6 +/- 12.6 mL/min/1.73 m(2) vs 1.0 +/- 15.5 mL/min/1.73 m(2); P = .67). A further 1:1 case-matched multivariate analysis of variance, matching patients and controls by AAA size and preoperative GFR, showed no difference in trend of GFR with time between groups (P = .15). Operative time was not significantly longer in LRV group (148.4 +/- 35.8 minutes vs 131.0 +/- 40.3 minutes; P = .07). No differences between groups were found for blood loss (585.7 +/- 264.2 mL vs 567.7 +/- 222.5 mL; P = .88), perioperative complications (5 vs 8; P = .12), or hospital length of stay (6.2 +/- 1.8 days vs 5.5 +/- 1.2 days; P = .10). A 6-month follow-up of renal function available in 12 patients of LRV group showed no significant decrease in GFR compared with postoperative values (70.8 +/- 24.8 mL/min/1.73 m(2) vs 69.1 +/- 23.5 mL/min/1.73 m(2); P = .86). At duplex scan, the reconstructed LRV could be insonated in nine of these 12 patients and all were patent. CONCLUSIONS: LRV division during AAA repair was associated with larger aneurysms and preoperative subclinical renal function impairment. In these patients, LRV reconstruction was associated with the maintenance of preoperative renal functional status without significantly lengthening of operative time or increasing the complications from surgery.     

Morbidity and mortality associated with renal insufficiency and endovascular repair of abdominal aortic aneurysms: a 5-year experience

To evaluate the outcome of patients with renal insufficiency undergoing endovascular repair of abdominal aortic aneurysm (AAA), data were prospectively collected between 1998 and 2003 on patients undergoing elective repair of their AAA with a stent graft. The patients were divided into 2 groups: those with serum creatinine (Crs) concentrations <1.2 (Group A) and those with Crs > or =1.2 mg/dL not requiring hemodialysis (Group B). The outcomes of the procedure for these 2 groups were compared. Different variables that existed between the 2 groups and contributed to mortality included estimated blood loss (EBL), volume of contrast used in the operating room, incidence of diabetes (DM), tobacco use, and history of myocardial infarction (MI). In total, 213 patients underwent elective repair of their AAA with use of a stent graft: 61% who had a Crs <1.2 mg/dL (Group A) and 39% who had a Crs > or =1.2 mg/dL not requiring dialysis (Group B). Among 129 patients with normal renal function there was an 18.6% complication rate and 1.6% mortality rate. Of 83 patients with renal insufficiency not on hemodialysis 30.1% (Fisher's Exact Test = 0.076) had 1 or more complications and there was a 6% (Fisher's Exact Test = 0.166) mortality rate. One patient in Group A (0.8%) progressed to hemodialysis and 5 (6%) patients in Group B progressed to end-stage renal disease requiring hemodialysis (p=0.068). A statistically significant higher proportion of the patients in Group B had a history of MI (p<0.001). There was no difference in the amount of EBL between the 2 groups, but a significantly lower amount of contrast (p<0.05) was used in patients with renal insufficiency.