Endovascular Abdominal Aortic Aneurysm Repair: Does Gender Matter?

Substantial differences across genders have been documented for the natural history and clinical course of cardiovascular diseases. This studys objective is to compare preoperative characteristics, intraoperative events, and postoperative outcomes in men and women undergoing endovascular abdominal aortic aneurysm repair (EVAR). We hypothesized that despite gender anatomic specificities, EVAR may achieve similar results across genders. We included 241 consecutive patients who underwent elective EVAR at our institution from December 1996 through May 2003. Demographic variables and comorbidities were collected by chart review, and intraoperative events were from surgical notes. Baseline anatomic characteristics were evaluated on the last preoperative computed tomography (CT) scan. Radiologic outcomes were evaluated on all postoperative CT scans, and clinical follow-up information was abstracted from charts. Women constituted 12% (n = 29) of our cohort and were older than men (79.9 vs. 74.9 years, p = 0.0003). When compared to men, they had aneurysms with similar diameter (54.1 vs. 55.5 mm, p = 0.491) but narrower (23.1 vs 25.5 mm, p < 0.0001) and shorter (18.9 vs. 30.4 mm, p < 0.0001) proximal necks. Female iliac arteries were narrower (9.6 vs. 11.4 mm, p < 0.0001), with higher calcification scores (2.5 vs. 2.3, p = 0.047) but lower tortuosity indexes (1.2 vs. 1.3, p = 0.0001). Additional access maneuvers were more frequent in women: iliac access angioplasty (31% vs. 10.9%, = p = 0.007), uni-iliac conversion (13.8% vs. 1.4%, p = 0.005), and iliac chimney conduit (12.1% vs. 1.2%, p = 0.0001). There was a trend toward longer fluoroscopy time in women (34.6 vs. 26.9 min, p = 0.056). The following postoperative outcomes at 24 months were similar in women and men: freedom from endoleak (63.4% vs. 72.7%, p = 0.74), reintervention rate (28% vs. 24.5%, p = 0.878), aneurysm shrinkage (24.3% vs. 68.7%, p = 0.199), aneurysm expansion (0% vs. 3%, p = 0.213), and survival (92.9% vs. 84.3%, p = 0.341). There was a trend toward higher rates of neck dilation relative to preoperative diameter in women (48.5% vs. 16% at 12 months, p = 0.059) and toward lower limb patency rates in men (100% vs. 92.8%, p = 0.098). In sum, women have shorter proximal necks and smaller and more calcified iliac arteries, which increases the necessity of access-related additional maneuvers. Despite being older and having a less favorable anatomy, women can expect similar technical and clinical outcomes after EVAR.Presented at the 13th Annual Winter Meeting of the Peripheral Vascular Surgery Society, Steamboat Springs, CO, January 31-February 2, 2004.S. M. Sampaio is a recipient of the Edward S. Rogers Clinical Research Fellowship in Vascular Surgery.     

Percutaneous Access for Endovascular Abdominal Aortic Aneurysm Repair: Can Selection Criteria Be Expanded?

Previous reports suggest that percutaneous access for endovascular abdominal aortic aneurysm repair (P-EVAR) is as safe as open access (O-EVAR) in patients with favorable femoral anatomy. Severe femoral artery calcification and obesity have been considered relative contraindications to P-EVAR, but these criteria have not been evaluated. The purpose of this study was to assess the postoperative anatomic changes associated with P-EVAR versus O-EVAR using three-dimensional (3-D) computed tomographic (CT) reconstruction and to evaluate the overall results of the two procedures in a group of patients with suboptimal femoral anatomy. During a recent 26-month period, 173 patients underwent EVAR at our institutions, including 35 P-EVARs. Of these, 22 (63%) had complete pre- and postoperative CT imaging of the femoral arteries. These subjects were compared to 22 matched controls who underwent O-EVAR during the same period. Automated 3-D reconstructions were used to measure the following anatomic femoral artery parameters before and after EVAR: arterial depth, calcification score, minimum diameter and area, and maximum diameter and area. Of the 88 study arteries, 50 underwent open access and 38 percutaneous access (Proglide, n=11; Prostar XL, n=27). Both groups were similar regarding sheath size, number of components, operative time, blood loss, and length of stay. Significantly more O-EVAR subjects suffered groin complications (p=0.02), including five hematomas, two wound infections, two femoral thromboses, and one vessel which required patch repair. In the P-EVAR group there was only one hematoma, which was managed conservatively. There was no difference between the P-EVAR and O-EVAR groups with respect to femoral artery calcification (Agatston scores 667+/-719 vs. 945+/-1,248, p=0.37). Obesity (body mass index >30) was documented in six (27%) of both the P-EVAR and O-EVAR groups (p=nonsignificant). Pre- and postoperative CT-derived anatomic data showed a significant decrease in the minimal vessel area with O-EVAR compared to P-EVAR (p=0.02). This study demonstrates that patients with obesity or severely calcified femoral arteries can be successfully treated percutaneously with fewer minor groin complications.     

Aortic Neck Dilation after Endovascular Abdominal Aortic Aneurysm Repair: Should Oversizing Be Blamed?

Long-term durability after endovascular abdominal aortic aneurysm repair (EVAR) is dependent upon the maintenance of an effective seal between the endograft and the proximal landing zone. Continuous neck dilation might lead to the loss of such a seal. This study aims at evaluating the incidence, risk factors, and clinical consequences of post-EVAR aneurysm neck dilation in patients treated with two types of endografts: AneuRx^® and Ancure^®. We reviewed data concerning all consecutive patients submitted to primary EVAR using the AneuRx and Ancure devices. Preoperative neck anatomic characteristics (diameter, calcification, and thrombus load) were evaluated, and device oversize percentage was calculated. Postoperative same-level neck diameter was measured on all postoperative computed tomographic (CT) scans. Probabilities of neck dilation (≥10% and ≥15%) relative to preoperative diameter and first postoperative diameter were estimated with the Kaplan-Meier method and compared between patients using both types of endograft. The impact of anatomic characteristics on neck dilation incidence was evaluated using Cox proportional hazards models. Mean neck dilation was compared between patients with and without device migration and proximal type I endoleak. Both groups had similar probabilities of dilating >10% relative to preoperative diameter and to first postoperative diameter. Proximal necks in AneuRx-treated patients had higher probabilities of dilating ≥15% relative to preoperative diameter than Ancure-treated patients (45.5% vs. 18.7% at 1.5 years, p = 0.025), but the probability of such dilation relative to the first postoperative diameter was not different between the two groups (12.4% vs. 9.1% at 1.5 years, p = 0.832). None of the preoperative neck characteristics was associated with neck dilation risk. Device oversize percentage was correlated with the percentage of neck dilation at first postoperative CT scan relative to preoperative diameter in both the AneuRx (correlation coefficient = 0.469, p < 0.0001) and the Ancure (correlation coefficient = 0.464, p < 0.011) groups, but it was not correlated with the percentage of neck dilation at 1 or 1.5 years relative to first postoperative CT scan in either group. Patients with and without caudad device migration (≥5 mm) had similar percentages of neck dilation at 1.5 years relative to preoperative diameter, but migrators had higher mean percentages of dilation at 1.5 years relative to first postoperative neck diameter (11.4% vs. 5.6, p = 0.012). Two phenomena may be differentiated: an immediate postimplant dilation, strongly correlated with the percentage of oversize and more likely to reach values ≥15% with an AneuRx device than with an Ancure graft, and a subsequent dilation, relative to the first postoperatively measured diameter, equally probable with either type of device, not correlated with the percentage of oversizing but associated with caudad device migration. Our study does not support any adverse role for the degree of oversize.Presented at the Twenty-sixth Meeting of the Canadian Society for Vascular Surgery, October 22-23, 2004, Quebec City, Quebec, Canada.J. M. Panneton is currently at Eastern Virginia Medical School and Vascular and Transplant Specialists, Norfolk, VA.     

Can the Internal Iliac Artery Be Safely Covered during Endovascular Repair of Abdominal Aortic and Iliac Artery Aneurysms?

Aneurysmal involvement of the common iliac (CIA) or the internal iliac arteries (IIA) have been relative contraindications for safe endovascular aortic aneurysm (AAA) repair. Our goal was to review our experience in dealing with this problem by performing permanent coverage of one or both IIA during endoluminal repair of aneurysms of the aortoiliac region and to develop a safe, durable strategy. Of the 228 consecutive patients who had endoluminal repair of abdominal aortic (AAA) and iliac artery (IAA) aneurysms between 4/1999 and 4/2001 at our institution, 49 patients underwent coverage and/or coil embolization of one or both IIA during repair because of complex aortoiliac anatomy. These patients were evaluated prospectively for short-term adverse outcome. These results showed that CIA or IIA aneurysms can be managed safely during endoluminal repair of AAA. The IIA can be covered or embolized with minimum adverse consequences in patients who have inadequate CIA for deployment of the aortic or iliac endograft. Unilateral IIA occlusion is well tolerated. We advocate that whenever bilateral IIA occlusion is necessary during endovascular aneurysm repair, one of the IIAs should be revascularized if it is not aneurysmal.     

Treatment of a Left Common Iliac Aneurysm with Endovascular Powerlink® Stentgraft in a Patient with an Occlusion of a Left Common Iliac Stent

Isolated iliac aneurysms are uncommon and account for only 2% of all abdominal aneurysms. Typically, patients presenting with this pathology are operated on surgically. In our patient, however, surgery could have been an option but the patient had undergone a laparotomy more than 50 years earlier because of a gun-shot wound, so we preferred an endovascular repair. Furthermore, regular endovascular repair with a straight tube stentgraft was impossible due to the absence of a proximal neck. Consequently, we opted for placing a bifurcated stentgraft to exclude the iliac aneurysm.     

Open Repair for Ruptured Abdominal Aortic Aneurysm: Is It Possible to Predict Survival?

The aim of the study was to determine variables that could be used to predict survival in patients with ruptured abdominal aortic aneurysm (RAAA) and to assess the accuracy of the Glasgow Aneurysm Score (GAS) and the Acute Physiology Chronic Health Evaluation II (APACHE-II). From January 1998 to July 2006, 103 patients underwent operations for RAAA. For each patient, 44 variables were retrospectively recorded in a database. Data were analyzed with univariate and multivariate methods. In the univariate analysis significant predictors of death were hypotension (p=0.001), preexisting peripheral vascular disease (p<0.001), renal insufficiency (p=0.037), chronic obstructive pulmonary disease (p=0.028), level of HCO(3)(-) (p<0.001), intraperitoneal rupture (p=0.001), blood transfused (p<0.001), cardiac complications (p<0.001), and APACHE-II score (p=0.001). Multivariate analysis confirmed statistical significance for coexisting peripheral vascular disease (p<0.001), diastolic blood pressure at admission <60 mm Hg (p=0.039), APACHE-II score >18.5 (p=0.025), HCO(3)(-) <21 mg/dL (p<0.001), and intraperitoneal rupture of the aneurysm (p=0.011) as predictors of death. Results of the study suggested that different factors can be helpful in identifying those patients whose operative risk is prohibitive. APACHE-II, contrary to GAS, is an accurate system to predict postoperative death after repair for RAAA.     

Do Internal Iliac Arteries Contribute to Vascularization of the Descending Colon during Abdominal Aortic Aneurysm Surgery? An Intraoperative Hemodynamic Study

The inferior mesenteric artery (IMA) is the nutrient artery for the descending colon. Colon ischemia after repair of abdominal aortic aneurysm (AAA) can be prevented by routine or elective revascularization of the IMA. In case of occlusion of the IMA, revascularization of the internal iliac artery (IIA) has been recommended but its effectiveness has never been documented. In this study, intraoperative hemodynamic monitoring of the IMA was performed to determine if the IIA contributed significantly to the region supplied by the IMA. From January 1998 to August 1999, a total of 223 patients underwent AAA repair at 11 vascular surgery centers. The IMA was occluded in 113 of these patients (51%). This study involves the other 110 patients (49%) with patent IMA. Study consisted of measuring residual systolic arterial pressure in the IMA (IMAP) immediately after AAA repair. To compensate for blood pressure variations, systolic pressure in the radial artery (RAP) was measured concurrently and the inferior mesenteric index (P) was calculated by dividing IMAP by RAP. Measurements were made before and during cross-clamping ofthe IIA to obtain two corresponding indexes-i.e., P1 and P2, respectively. Mean P1 and P2 were 0.61 (95% confidence interval, 0.8-0.4) and 0.58 (95% confidence interval, 0.55-0.61), respectively, with p <0.001. These findings show that cross-clamping of the IIA during AAA repair resulted in a significant decrease in IMAP.     

Open Versus Endovascular Repair of Abdominal Aortic Aneurysms: What Does Each Really Cost?

Endovascular repair (EVAR) of abdominal aortic aneurysm (AAA) has emerged as an alternative to open repair (OR). The aim of this study was to compare the clinical outcomes and specific costs of these procedures since commercialization.A retrospective analysis of 119 consecutive infrarenal AAA repaired via an EVAR or an OR between July 2000 and September 2001 was performed. Patient charts were reviewed. Diagnostic-related group (DRG) classification and payer mix were identified. The hospital cost accounting system was accessed to obtain actual variable direct cost (AVDC) for the two groups. Percentages of the mean AVDC for the two groups were compared in the following cost categories: graft, operating room, radiology procedures and supplies, pharmacy, respiratory therapy, clinical laboratories, surgical floor, and monitored unit. Hospital profit margins were determined. Fifty-five patients underwent EVAR and 64 patients underwent OR. Mean aneurysm size was 5.5Â cm (EVAR) and 6.1Â cm (OR). Mean intensive care unit (ICU) stay was 0.09 days for EVAR vs. 3.5 days for OR (p < 0.05). Mean length of stay (LOS) was 1.96 days for EVAR vs. 7.3 days for OR (p < 0.05). Reimbursement was based on DRG 110, 47.3% in the EVAR and 79.7% in the OR group (p < 0.05), and DRG 111, 50.9% in the EVAR group and 12.5% in the OR group (p < 0.05). The payer mix showed no significant differences between the two groups. Mean AVDC for EVAR was 1.74 times that of OR. Significant differences in the distribution of costs were found in the following: graft costs (58% vs. 6.3%, p < 0.05), radiology procedures and supplies (3.9% vs. 0.1%, p < 0.05), pharmacy (1.9% vs. 10.5%, p < 0.05), and monitored unit (7.3% vs. 24.65%, p < 0.05) comparing EVAR vs. OR, respectively. Median cost of an endovascular graft was 22.4 times that of the standard graft for OR. Average hospital profit margins for an EVAR case was 49.5% vs. 88.6% for OR. Despite significant differences in monitored unit utilization, pharmacy services, and respiratory therapy services by the OR group, the cost of EVAR is appreciably more expensive. Furthermore, increased DRG reimbursement, and decreased ICU use and LOS do not compensate for the cost of EVAR. The main cost of EVAR is the cost of the graft itself. Hospital profit margins are acceptable with both the EVAR and OR procedures at this time; however, with proposed reductions in reimbursement, the ability to cover the cost of this new technology may be threatened.     

What Determines and Are the Consequences of Surveillance Intensity after Endovascular Abdominal Aortic Aneurysm Repair?

Follow-up examinations are advised 1, 3, 6, 12, 18, and 24 months and yearly thereafter by the European Collaborating Group on Stent-Graft Techniques for Abdominal Aortic Aneurysm Repair (EUROSTAR). The aim of this study was to evaluate the determinants and consequences of surveillance completeness. Patients who underwent endovascular abdominal aortic aneurysm repair between October 1996 and August 2004 and enrolled in the EUROSTAR registry were analyzed. Two groups were compared: patients who attended all scheduled visits (group A) and those who came infrequently (group B). Odds ratios and hazard rates (HRs) with 95% confidence intervals (CIs) were determined to detect which patient characteristics and complications were associated with follow-up intensity. Of the 4,433 patients, 1,538 (35%) attended all scheduled visits until the end of follow-up (group A). Analysis of patient characteristics demonstrated that intensive visitors were more often smokers, hyperlipemic, and considered unfit for open surgery or general anesthesia. Complications during follow-up, including endoleaks (24% vs. 20%), kinking (3.5% vs. 2.5%), and migration (4.9% vs. 3.5%), appeared significantly more frequently in group A. Despite intensive follow-up of this category, still a greater proportion died (12% vs. 9%, adjusted HR = 1.5, 95% CI 1.2-1.8). After 84 months of follow-up, the cumulative survival rates in groups A and B were 71% and 74%, respectively (p < 0.0001). It seems that follow-up intensity was based on baseline patient characteristics. High-risk patients had, despite more intensive surveillance, still more complications after adjustment for patient, morphological, and center-specific characteristics. Further assessment is indicated to evaluate the effectiveness of different frequencies of surveillance visits.     

What are the Risk Factors for Renal Failure following Open Elective Abdominal Aortic Aneurysm Repair?

ObjectivesRenal failure following abdominal aortic aneurysm (AAA) repair is a common and significant complication. The objective of this study was to identify risk factors for renal failure following open elective AAA repair.DesignA retrospective analysis of prospectively collected multi-centre data.MaterialsConsecutive data on patients undergoing open elective AAA repair were collected between January 2000 and December 2010. Patients with pre-operative serum creatinine >200 μmol/L were excluded.MethodsRenal failure was reported by clinicians and included all patients requiring post-operative renal-replacement therapy. Univariate and multivariate analyses were used to identify renal failure risk factors. A simplified clinical risk score was developed.ResultsPost-operative renal failure occurred in 140 (6.0%) of 2347 patients and was associated with age >75 (OR = 1.58, 95%CI 1.11–2.26), symptomatic AAA (OR = 1.77, 95%CI 1.24–2.52), supra/juxta renal AAA (OR = 2.17, 95%CI 1.32–3.57) pre-operative serum creatinine >150 (OR = 2.75, 95%CI 1.69–4.50), treated hypertension (OR = 1.87, 95%CI 1.28–2.74), and respiratory disease (OR = 2.08, 95%CI 1.45–2.97). Patients with post-operative renal failure had significantly higher 30-day mortality (35.0% vs. 4.3%, p < 0.001).ConclusionsRenal failure following open elective AAA repair was associated with an increased risk of mortality. Risk factors for post-operative renal failure were identified and a simple clinical risk score developed to facilitate focussed care strategies for high-risk patients.     

Endovascular Repair of Ruptured Abdominal Aortic Aneurysm – a Challenge to Open Repair? Results of a Single Centre Experience in 20 Patients

Introduction: the mortality from ruptured abdominal aortic aneurysm (AAA) remains in the region of 50% despite advances in critical care. Endovascular repair of AAA has been shown to be associated with reduced physiological stress in the elective setting. It is hypothesised that the reduced physiological stress associated with EVAR may improve the outcome in patients with ruptured AAA. Methods: a feasibility study of endovascular repair of ruptured AAA was undertaken at the University Hospital, Nottingham, U.K. between 1994 and 2000. Patients admitted with ruptured AAA were assessed by a team familiar with endovascular techniques for elective repair of AAA. After giving informed consent patients underwent spiral computed tomographic angiography (CTA) in the majority of cases. Patients were then transferred to the operating theatre for EVAR. Results: twenty patients underwent repair of ruptured AAA. Of these 20 patients, seven were referred from another hospital. Eight patients were considered unfit for open repair. The median duration of procedure was 180 min (range 120–480) and median blood loss was 1200 ml (range 750–2000 ml). The overall peri-operative mortality was 45%. A number of intra-operative and peri-operative procedures (both open and endovascular) were required to ensure aneurysm exclusion and to deal with the complications of endovascular surgery. Conclusions: ruptured AAA remains a particularly hazardous condition to treat. There are a number of advantages of EVAR in this condition. A number of the problems early in the experience of EVAR have been addressed, but further experience is required to demonstrate its efficacy when compared with open repair.