Faculty Bibliography

PURPOSE: To describe a technique of aortic clamping during endovascular aneurysm repair (EVAR) in patients with ruptured abdominal aortic aneurysms (AAA) and circulatory collapse. TECHNIQUE: A balloon catheter is inserted percutaneously from the femoral artery and inflated in the suprarenal aorta. An introducer sheath must support the balloon. The stent-graft is passed from the contralateral groin and deployed beneath the balloon. The sheath makes it possible to retrieve the balloon after the endograft has been deployed. Carbon dioxide facilitates angiography while the aortic blood flow is arrested. CONCLUSIONS: The aortic stent-graft can be deployed while the aorta is continuously 'clamped' from a transfemoral approach. This may allow EVAR in patients with circulatory collapse due to aneurysm rupture

In 1990 Juan C. Parodi performed the first endovascular abdominal aortic aneurysm (AAA) repair in Buenos Aires. Two years later, in 1992, Parodi and Claudio Schonholz visited Montefiore Medical Center in New York to perform with us the first endovascular AAA repair to be done in the United States. Since then the Montefiore/Einstein vascular group has performed 1522 endovascular grafts in 674 patients for many types of vascular lesions using a variety of both surgeon-made and industry-made devices. The purpose of the present article is to describe the events that surrounded the performance of the first seminal endovascular AAA repair at our institution on November 23, 1992

OBJECTIVE(S): We have previously shown that type II endoleak size is a predictor of aneurysm growth after aortic endografting. To better understand this observation, we investigated the influence of endoleak size on pressure transmitted to the aneurysm wall and its distribution within the aneurysm sac. METHODS: In an ex vivo model, an artificial aneurysm sac was incorporated within a mock circulation comprised of rubber tubing and a pulsatile pump. Three strain-gauge pressure transducers were placed in the aneurysm wall at different locations, including the site of maximum aneurysm diameter. The aneurysm was filled with either human aneurysm thrombus or dough that mimicked thrombus and simulated type II endoleaks of varying volumes (1 to 10 mL) were created. Aneurysm wall pressure (AWP) measurements were recorded at mean arterial pressures (MAPs) of 60, 80, and 100 mm Hg. Correlation coefficients ( r ) and analysis of variance were used to assess the relationship between endoleak volume and AWP. RESULTS: Increasing endoleak volume '3 cm 3 resulted in proportionally increased AWP at all levels of MAP and at all sites, with highest pressures recorded at the site of the maximum aneurysm diameter (r = 0.83 when MAP = 100 mm Hg; r = 0.85 when MAP = 80 mm Hg; r = 0.88 when MAP = 60 mm Hg; P < .001). AWP plateaued when the endoleak volume was >3 cm 3 . Pressure distribution within the sac was not uniform. Although the difference was within +/-10%, statistically significant higher AWPs were observed at the site of maximum aneurysm diameter (P <.001). AWP also correlated with MAP. CONCLUSIONS: Increasing type II endoleak volume results in proportionally higher AWP, which is greatest at the site of maximum aneurysm diameter. This study confirms the clinical observation that type II endoleak volume and MAP may be important predictors of aneurysm expansion. CLINICAL RELEVANCE: Our experimental model of a type II endoleak revealed that endoleak size is a significant factor that influences the magnitude of pressure transmission into the aneurysm wall. Increasing volume of the endoleak nidus was associated with proportionally higher aneurysm sac pressures. This mechanism may, in fact, account for the increased risk of aneurysm expansion observed in our clinical experience, thereby suggesting the need for more aggressive surveillance and possibly earlier intervention for patients with larger endoleaks

The interest in and overall usage of endovascular procedures for the treatment of lower extremity ischemia continues to grow at a rapid pace. An increasing number of centers throughout the world are gaining experience with subintimal angioplasty. Promising results have been reported and the application of the technique has been expanded to include the iliac and crural arteries. The technique of subintimal angioplasty and several variations are discussed. Although primary patency rates compared with bypass are relatively low for patients undergoing subintimal angioplasty, limb salvage rates remain high. When a subintimal angioplasty fails, it frequently does so without the recurrence of symptoms, especially when a gangrenous lesion or ulcer has healed. Given the many advantages of this technique, which include reduced anesthesia requirements, a minimally invasive approach, and potential reductions in length of stay and cost, subintimal angioplasty will continue to have a role in the treatment of lower extremity ischemia. When applied judiciously, bypass options may be preserved. This does not, however, mean that the availability of this technique should be used as justification to lower the threshold for the treatment

Endovascular aortic aneurysm repair (EVAR) in patients with ectatic iliac arteries is feasible; however, most studies have reported experience from single institutions where distal flare techniques with endograft components were used on an 'off-label basis.' The Zenith endovascular graft allows adequate seal in ectatic common iliac arteries (CIAs) with diameters up to 20 mm. To determine whether large or ectatic CIAs are a risk factor for early and late endograft failure, we analyzed data from the Zenith U.S. multicenter trial. Among 352 patients receiving the endograft in the Zenith u.s. clinical study, 156 patients (44%) had at least one ectatic iliac artery (maximum diameter between 14 and 20 mm), whereas 22 (6.3%) had bilateral CIAs of normal diameter (< 14 mm). Variables analyzed included those defined by the reporting standards for EVAR (SVS/AAVS) as well as iliac-related outcome and indications for secondary iliac interventions. Univariate (Kaplan-Meier [KM] receiver operating characteristics curve, and Cox regression analyses were used to determine the association between CIA diameter and iliac-related complications. The median follow-up period was 24 months. Technical success was similar (>99%) for patients with ectatic and normal CIAs. Only one late type I distal endoleak was reported and was attributed to failure of distal iliac seal in a patient with ectatic CIAs. Freedom from iliac-related secondary intervention (IRSI) was not significantly different between the groups (KM, log-rank test, p = 0.98) with rates at 1, 12, and 24 months of 98%, 97%, and 95% for patients with ectatic CIAs, and 100%, 95%, and 95% for patients with normal iliac arteries, respectively. Moreover, Cox regression analysis revealed that the maximum CIA diameter was not a significant predictor of freedom from IRSI (hazard ratio, 0.98; 95% confidence interval, 0.7-1.4; p = 0.98). In patients with large CIAs, indications for IRSI included distal type I endoleak (1, 0.6%), type III endoleak (1, 0.6%), graft limb occlusion (4, 2.6%), and device stenosis (1, 0.6%). The only IRSI in a patient with normal CIAs was performed for device stenosis (4.6%). In conclusion, the Zenith endograft is effective for EVAR in patients with ectatic CIAs. Moreover, the presence of large CIAs was not associated with an increased risk of adverse iliac-related outcome or subsequent IRSI. Long-term surveillance, however, is mandatory, as IRSIs may be necessary

BACKGROUND: To evaluate whether abdominal aortic aneurysm (AAA) growth in individual patients can be characterized as continuous or discontinuous (staccato). STUDY DESIGN: From 1996 to 2002, 609 patients presented with unruptured AAAs. Of these, 278 underwent prompt repair and 331 were observed. In this study, we included 52 patients (16% of the latter group) who had at least four CT scans and were observed for 18 months or longer without any intervention. AAA growth was defined as any increase in diameter of >/= 3 mm over any observation period(s). AAA nongrowth was defined as absence of growth for at least 6 months. Staccato growth was defined as at least one period of nongrowth combined with at least one period of growth. RESULTS: The 52 patients had a mean age of 75 +/- 8 (SD) years. The mean observation period was 42 +/- 20 months and the mean AAA diameter growth rate was 3.6 +/- 2.4 mm/y. Only 12 of these 52 patients (23%) demonstrated continuous growth. Staccato growth occurred in 34 patients (65%). Six patients (12%) showed no growth at all over 18 to 57 months (mean 30 months). No correlation was observed between initial diameter of AAAs and a patient's individual growth rate during the whole observation period (R = 0.04, p = 0.46). CONCLUSIONS: Individual AAA behavior is usually characterized by periods of nongrowth alternating with periods of growth, ie, staccato growth. Some aneurysms may have long periods of nongrowth. Accordingly, management decisions cannot be based on the presumption that observed growth rates of AAAs can be extrapolated to predict future growth rates

PURPOSE: Hypogastric artery interruption is sometimes required during aortoiliac aneurysm repair. We have not experienced some of the life-threatening complications of pelvic ischemia reported by others. Therefore we analyzed our experience to identify factors that help minimize pelvic ischemia with unilateral and bilateral hypogastric artery interruption. METHODS: From 1995 to 2003, 48 patients with aortoiliac aneurysm required interruption of both hypogastric arteries as part of endovascular (n = 32) or open surgical (n = 16) repair. During endovascular aneurysm repair coils were placed at the origin of the hypogastric arteries, and bilateral hypogastric artery interruptions were staged at 1 to 2 weeks when possible. Open surgery necessitated oversewing or excluding the origins of the hypogastric arteries and extending the prosthetic graft to the external iliac or femoral artery. Collateral branches from the external iliac and femoral arteries were preserved, and patients received systemic heparinization (50 units/kg). RESULTS: There was no buttock necrosis, ischemic colitis requiring colon resection, or death with the bilateral hypogastric artery interruption. Initially buttock claudication developed in 20 patients (42%), but persisted in only 7 patients (15%) at 1 year. New onset of impotence occurred in 4 of 28 patients (14%), and there were no neurologic deficits. CONCLUSIONS: Bilateral hypogastric artery interruptions can be accomplished with limited morbidity. When hypogastric artery interruption is needed during endovascular aneurysm repair, certain principles help minimize pelvic ischemia. These include hypogastric artery interruption at its origin to preserve the pelvic collateral vessels, staging bilateral hypogastric artery interruptions when possible, preserving collateral branches from the femoral and external iliac arteries, and providing adequate heparinization of the patient during these procedures