Brian R. Hopkinson

Clinical experience with a bifurcated endovascular graft for abdominal aortic aneurysm repair

PURPOSE The purpose of this study was to test a transfemoral system of bifurcated endovascular graft insertion for aortic aneurysm repair. METHODS Bifurcated endovascular grafts were inserted through bilateral femoral artery cutdowns in 41 patients. The results were assessed by completion angiography and follow-up computed tomography. RESULTS The second half of the study included more aneurysms 6 cm or larger (p < 0.05) and more instances of short proximal neck (p < 0.05), proximal neck angulation (p < 0.05), and iliac angulation (p < 0.05). Despite the increasingly challenging anatomy, the results were better in the second half of the study as illustrated by the lower overall combined morbidity/mortality rate (15% vs 50%) and higher overall success rate (85% versus 65%). The mortality rate for the series as a whole was 7.5%. Mean follow-up was 18.8 months for the first 20 patients and 10.9 months for the second 20. The commonest complication in the first half of the study was graft thrombosis (n = 5). This complication was absent from the second half of the study because of routine adjunctive stenting. Two patients died of complications of endovascular repair. In both cases aneurysm rupture on the third postoperative day was associated with coagulopathy and angiographic signs of perigraft leak. CONCLUSION Aneurysm exclusion with a bifurcated endovascular graft was feasible in a wide range of patients, but when the aneurysm was not entirely excluded from the circulation, the risk of rupture persisted.

Common iliac artery aneurysms in patients with abdominal aortic aneurysms

OBJECTIVES To determine the incidence of common iliac artery (CIA) aneurysms in patients with abdominal aortic aneurysms (AAA) and to evaluate the relationship between AAA and CIA diameter. METHODS Spiral CT angiography was used to measure the maximum diameters of the abdominal aorta and the common iliac arteries of 215 patients with AAA. RESULTS The median CIA diameter was 1.7 cm--significantly greater than the published mean of 1.25 (2 S.D. = 0.85-1.65) cm of an age-matched, non-vascular population. Thirty-four patients (16%) had unilateral and 26 patients (12%) bilateral CIA aneurysms > or = 2.4 cm diameter. Eight-six vessels (20%) were affected. Right CIA diameters were wider than left CIA diameters (p < 0.0001, Wilcoxon matched-pairs signed rank test). The correlation between AAA size and CIA diameter was weak. CONCLUSIONS The AAA population has abnormally dilated common iliac arteries. In this population, common iliac artery aneurysms should be defined as those greater than 2.4 cm diameter. 20% of CIAs in patients with AAA are aneurysmal according to this definition.

Early results of endovascular aortic aneurysm surgery with aortouniiliac graft, contralateral iliac occlusion, and femorofemoral bypass

PURPOSE The aim of this study was to evaluate the feasibility of endovascular aortic aneurysm repair with use of an aortouniiliac graft secured with self-expanding (Gianturco) stents. METHODS Thirty patients with a median age of 72 years (age range, 52 to 86 years) and aneurysm diameter of 6.0 cm (range, 4.0 to 9.0 cm) were treated with an aortouniiliac endovascular graft. Of these 30 procedures, 28 were carried out electively and two as emergencies for leaking aneurysm. Of the 30 patients, 21 (70%) were considered to be at high risk for open surgery. A modified Gianturco stent, Dacron graft, and Wallstent were used for these procedures. RESULTS Endovascular repair was successfully carried out in 25 of 30 (83.3%) patients. All these patients were mobile and had resumed a normal diet within 48 hours of the procedure. The overall 30-day mortality rate was two in 30 (6.6%), but it was one in 28 (3.5%) for the elective cases; all deaths occurred in the group at high risk for surgery. Other complications encountered within 30 days of procedure included myocardial infarction in one patient, pneumonia in two patients, homonymous quadrantanopia in one patient, and colonic ischemia in one patient, giving an overall morbidity rate of four in 30 (13.3%). At a median follow-up of 4 months (range, 1 to 13 months), 27 of 30 (90%) patients remain alive and well. CONCLUSION Endovascular aortouniiliac repair of abdominal aortic aneurysm with Gianturco stent is feasible in both elective and emergency situations. It appears to be minimally traumatic, and the majority of patients deemed to be at high risk for open surgery can safely undergo endovascular repair. However, data on more patients with longer follow-up is required to determine its role in the management of abdominal aortic aneurysm.

Transfemoral endoluminal repair of abdominal aortic aneurysm with bifurcated graft

Traditional open repair of abdominal aortic aneurysm has disadvantages. We present our experience of transfemoral endoluminal repair with a bifurcated graft system. 29 patients with aortic aneurysm over 5.5 cm in diameter and 1 with a 3.2 cm aneurysm and bilateral iliac stenosis were assessed; 5 were suitable for the procedure. The operation was successful in all the patients, without haemodynamic compromise or major complications. This technique has the potential to reduce morbidity and mortality from abdominal aortic aneurysm. Further modifications are required to make it applicable to most aneurysms.

Long-Term Renal Function following Endovascular Aneurysm Repair with Infrarenal and Suprarenal Aortic Stent-Grafts

Purpose: To determine in a retrospective analysis the incidence of renal impairment (RI) following endovascular repair (EVR) of abdominal aortic aneurysm (AAA), to assess the morbidity and mortality in endograft patients with preoperative RI, and to examine the impact of suprarenal stent-grafts on renal function. Methods: From March 1994 to October 2001, 315 AAA patients (289 men; mean age 72.4±7.0 years) undergoing EVR were entered prospectively into a vascular registry. The patients received either an in-house custom-made stent-graft or one of several commercially made devices implanted with infrarenal or suprarenal fixation. Renal function was monitored by serum creatinine measurements prior to discharge and at 3, 6, and 12 months and annually thereafter. Preoperative RI was defined as a serum creatinine > 130 μmol/L and/or long-term dialysis. Postoperative RI referred to a >20% increase in the serum creatinine over baseline. Additional deterioration of renal function in patients with preoperative RI was referred to as postoperatively worsened RI. Results: Of the 315 patients treated, 220 (69.8%) were considered high risk (ruptured AAA or ASA grade III or IV). Sixty-nine (21.9%) patients had preoperative RI (6 [1.9%] on preoperative dialysis). A suprarenal stent-graft was used in 169 (53.7%) patients and infrarenal stent-graft in the remaining 146 (46.3%). The mean follow-up was 30.1 ±22.7 months. Postoperative RI occurred in 53 (16.8%) patients (24 [7.6%] transient, 29 [9.2%] persistent). Patients with preoperative RI had a significantly higher incidence of postoperatively worsened RI (37.7% versus 11.0%, p<0.0001) and a higher mortality related to RI (7.2% versus 1.6%, p=0.02). Suprarenal fixation had no influence on the incidence of RI, on perioperative mortality, or on mortality related to RI. The only significant predictive factor of postoperative RI was preoperative RI (risk ratio 5.09, 95% CI 2.38 to 10.87, p=0.0001). Conclusions: Endovascular AAA repair may lead to persistent postoperative RI in nearly 10% of cases, especially in patients with preoperative RI. Suprarenal stent-graft fixation does not seem to have any deleterious effect on renal function. Further long-term studies are required to confirm the innocuous nature of transrenal stent placement.

European Experience with a System for Bifurcated Stent-Graft Insertion

Purpose: To test an endovascular aneurysm exclusion system in the presence of a wide range of challenging anatomic features. Methods: Bifurcated endovascular stent-grafts were inserted in 52 patients and followed with serial computed tomography for up to 3 years. The device underwent several modifications during this time, the most significant of which represent the difference between the homemade (n = 42) and industry-made (n = 10) versions. Results: The initial procedural success rate was 92% in the homemade group and 100% in the industry-made group. In the 3 years of follow-up, the long-term success rate was 64% in the homemade group and 90% in the industry-made group. The primary reasons for failure in the homemade group were graft thrombosis due to kinking early in the series and proximal stent migration later in our experience. All cases of migration occurred when the neck was < 15 mm in length, the neck was lined with thrombus, or the stent was implanted > 15 mm from the renal arteries. Kinking was subsequently overcome by implanting Wallstents throughout the graft limbs. The sole failure in the industry-made group was a case in which collateral perfusion reached the aneurysm through patent lumbar arteries. Conclusions: The fruits of this experience are a better technique, a better device, and, most importantly, a better understanding of the systems limits, as reflected in the current selection criteria.

Durability of femorofemoral bypass grafting after aortouniiliac endovascular aneurysm repair

INTRODUCTION Endovascular aneurysm repair (EVAR) with aortouniiliac prostheses extends the morphologic range of aneurysms that can be treated and is potentially a more rapid and simple operation than bifurcated endovascular repair. It may, however, be limited by durability of the femorofemoral extra-anatomic bypass graft required to revascularize the contralateral lower limb. Previous studies of femorofemoral bypass grafts were performed almost exclusively in patients with occlusive disease. An 8-year single center experience with use of the femorofemoral bypass graft in aneurysmal disease is reported. METHODS All patients undergoing EVAR with an aortouniiliac endovascular stent graft over eight years (1994-2002) at a single institution were included in a retrospective study. Patient data were collected from a prospectively maintained local endovascular database. All patients gave informed consent and were part of an endovascular program approved by the local ethics committee. RESULTS Over the 8 years, 231 patients underwent EVAR with an aortouniiliac endovascular stent-graft. Median follow-up was 22 months. Localized wound complications were observed in 25 patients (11%). Cumulative 3-year patency rate for the femorofemoral bypass graft was 91%. At the end of 5 years 83% of grafts remained patent. CONCLUSIONS The femorofemoral bypass graft used during EVAR with aortouniliac stent grafts offers encouraging medium and long-term patency. When graft occlusion occurs, it is usually directly attributable to inadequate inflow from the endovascular stent graft itself or to endoluminal damage of the external iliac artery. Awareness and early detection of stent-graft distortion or complications in the external iliac artery may result in improved patency rates.

Anatomical suitability of ruptured abdominal aortic aneurysms for endovascular repair.

Purpose: To assess the anatomical suitability of ruptured abdominal aortic aneurysms (AAA) for emergency endovascular repair. Methods: All cases (46 patients [35 men; mean age 74 years, range 54–85]) in which computed tomographic angiography (CTA) confirmed AAA rupture over a 5-year period at our university hospital were reviewed for anatomical suitability for endovascular repair. Measurements were made by a radiologist experienced in anatomical assessment of CT criteria for elective endovascular aneurysm repair (EVAR). Results: The mean aneurysm neck length was 18 mm (range 0–59); 17 were conical, 13 straight, 4 barrel, and 6 reverse conical. Six cases had no proximal neck. Overall, 37 (80%) patients were unsuitable for EVAR according to our criteria. Nearly half the patients (22, 48%) had ≥2 adverse features. Unsuitable neck morphology (35, 76%) was the primary reason for exclusion, but CIA aneurysm (10, 22%) and EIA tortuosity (7, 15%) were secondary adverse features. Conclusions: With current stent-graft design, the majority of ruptured abdominal aortic aneurysms are anatomically unsuitable for endovascular repair.

Influence of Abdominal Aortic Aneurysm Size on the Feasibility of Endovascular Repair

PURPOSE To assess the effect of abdominal aortic aneurysm (AAA) size on overall aneurysm morphology with special attention to possible relationships among various anatomic variables that determine the feasibility of endovascular repair. METHODS One hundred sixty-eight patients were assessed with spiral computed tomographic angiography to measure the length and diameter of the AAA, the proximal neck, and the common iliac arteries. Anatomic variables were correlated with aneurysm size using Spearmans rank order correlation coefficients (rS); comparisons among small, intermediate, and large aneurysms were made using the Chi-square test. RESULTS Correlations between aneurysm size and the anatomic variables above were weak. The strongest association was between aneurysm size and aortic length (rS = 0.41, p < 0.001). Subgroup analysis showed no difference in proximal neck length, neck diameter, or overall suitability for endovascular repair between aneurysms greater or smaller than 5.5-cm diameter. However, significantly more short (< 1.5 cm), wide (> 3 cm), and hence, unsuitable proximal necks were found in patients with aneurysms > 7 cm in diameter (chi 2 = 7.8, p < 0.01). CONCLUSIONS Shortening and widening of the proximal neck seems to increase with aneurysm size but only after the aneurysm expands beyond 7 cm in diameter. Aneurysms with diameters in the 4.5- to 5.5-cm range are no more suitable for endovascular repair than those between 5.5 and 7 cm. The lack of any significant correlation between anatomic variables emphasizes the need for accurate preoperative assessment of the anatomy of each individual patient before endovascular repair.

The Zenith Aortic Stent-Graft: A 5-Year Single-Center Experience

Purpose: To evaluate the efficacy and midterm results of the Zenith stent-graft in the treatment of abdominal aortic aneurysms (AAA). Methods: Since March 1994, 364 patients have undergone endovascular repair of infrarenal AAA. Of the 94 who were treated with the Zenith stent-graft from 1996 to 2002, 88 patients (82 men; mean age 72.6 ± 6.5 years, range 47–88) with at least 6-month follow-up were analyzed. Sixty-one (69.3%) patients were considered at high risk for intervention; 7 ruptured AAAs were treated emergently. In all, 68 (77.3%) bifurcated stent-grafts (including 18 TriFab systems) and 20 aortomonoiliac configurations were used. Cumulative data on endoleak, migration, secondary procedures, and survival were evaluated with Kaplan-Meier analyses. Results: Implantation success was 97.7%; 2 (2.3%) access-related failures were converted to open repair (1 immediate, 1 at 3 months). There were 3 (3.4%) graft limb thromboses (2 immediate, 1 late), 3 (3.4%) cases of colon ischemia due to embolization in 1 and hypogastric artery occlusion in 2, and 1 (1.1%) renal infarction due to embolism. Three (3.4%) patients died within 30 days. Eleven (12.5%) endoleaks and 1 (1.1%) late endograft migration were recorded. The 5-year cumulative endoleak and migration rates were 15% and 7%, respectively. Sixty-three (71.6%) patients did not present any complication related to the repair during a mean follow-up of 20.6 ± 14.9 months (range 6–68); notably, no complications were associated with the 18 TriFab systems. Six (6.8%) secondary procedures were performed (31% 5-year cumulative secondary procedural rate). All 6 (6.8%) aneurysm-related deaths (the 3 perioperative, 2 from late AAA rupture, and 1 during a secondary procedure) and 14 of 18 (20.4%) non-aneurysm—related deaths occurred in high-risk patients; the 5-year cumulative survival rates were 57% for any death and 92% for aneurysm-related deaths. Conclusions: The Zenith stent-graft appears both safe and effective in terms of midterm outcome of endovascular aortic aneurysm repair.