Repetitive bypass and revisions with extensions for limb salvage after multiple previous failures.

The optimal treatment of patients facing imminent amputation after multiple (≥ 2) failed prior ipsilateral bypasses is unclear. We analyzed a group of patients undergoing multiple lower extremity bypasses for limb salvage to assess the utility of attempting multiple revascularizations. From 1990 to 2005, 105 revascularization procedures were performed in 55 limbs of 54 patients with imminent limb-threatening lower extremity ischemia after failure of ≥ 2 prior infrainguinal bypasses in the same leg. Fifty-five operations were the third procedure (Group A) and 50 operations were the fourth or more (Group B). We compared primary/secondary patency and limb salvage rates by Society for Vascular Surgery criteria. Limb salvage rates did not differ between patients undergoing a third bypass and those undergoing four or more bypasses at one year (62 versus 65%, NS) or at three years (58 versus 61%, NS). Secondary patency was not different between groups (76 versus 76%, P = NS) at one and three years (71 versus 70%, NS). Primary patency also did not differ between the two groups, at one year (24 versus 35%, NS), or at three years (11 versus 15%, NS). No differences were observed in morbidity and mortality rates between the groups. In conclusion, the likelihood of success of repetitive limb revascularization was unrelated to the number of previous failures. The expected incremental failure rate with each successive bypass was not found. These results, coupled with the three-year limb salvage rate of over 50% in patients who otherwise would have required amputation, lend support to aggressive use of limb revascularization in selected patients even after two or more failed bypasses.

Factors influencing the incidence of endovenous heat-induced thrombosis (EHIT).

INTRODUCTION: Extension of thrombus from the great saphenous vein into the common femoral vein can be an early postprocedural complication of endothermal ablation (ETA). METHODS: A retrospective review was performed over a 3-year period. Intraprocedural ultrasound images demonstrating the distance of the catheter tip to the saphenofemoral junction (SFJ) were available for 519 procedures, and this distance was measured. RESULTS: Twenty-one (4.0%) cases of endovenous heat-induced thrombus (EHIT) were diagnosed. In all, 15 (6.4%) EHITs occurred following endovenous laser ablation and 6 (2.1%) after radiofrequency (P = .02). Distance from catheter tip to SFJ, vein diameter, concomitant treatments, and perioperative anticoagulation were not significant risk factors for EHIT. Of the clinical factors assessed, gender (P = .002), Clinical, Etiologic, Anatomic and Pathophysiologic classification 3 to 6 (P = .003), history of prior thrombosis (P = .04), and Caprini thrombosis risk factor assessment score (P = .004) were significant. On multivariate analysis, Caprini score (P = .0002) and male gender (P = .0003) remained significant. CONCLUSIONS: Male gender and increased Caprini score are predictive factors for EHIT following ETA.

Percutaneous intervention for infrainguinal occlusive disease in women: equivalent outcomes despite increased severity of disease compared with men.

OBJECTIVES: Experience with open surgical bypass suggests similar overall outcomes in women compared with men, but significantly increased risk of wound complications. Percutaneous treatment of lower extremity occlusive disease is therefore an attractive alternative in women, although it is not clear whether there is a difference in outcomes between women and men treated with this technique. We sought to determine the results and predictors of failure in women treated by percutaneous intervention. METHODS: Percutaneous infrainguinal revascularization was performed on 309 women between 2001 and 2006. Procedures, complications, demographics, comorbidities, and follow-up data were entered into a prospective database for review. Patency was assessed primarily by duplex ultrasonography. Outcomes were expressed by Kaplan-Meier curves and compared by log-rank analysis. RESULTS: A total of 447 percutaneous interventions performed in 309 women were analyzed and compared with 553 interventions in men. Mean age in women was 73.2 years; comorbidities included hypertension (HTN) (86%), diabetes melitus (DM) (58%), chronic renal insufficiency (CRI) (15%), hemodialysis (7%), hypercholesterolemia (52%), coronary artery disease (CAD) (42%), and tobacco use (47%). Indications in women included claudication (38.0%), rest pain (18.8%), and tissue loss (43.2%). Overall primary & secondary patency and limb-salvage rates for women were 38% +/- 4%, 66% +/- 3%, and 80% +/- 4% at 24 months. In this patient sample, women were significantly more likely than men to present with limb-threatening ischemia (61.6% vs 47.3%, P < 0.001) and have lesions of TASC C and D severity (71.4% vs 61.7%, P < .005). However, there were no significant differences in primary and secondary patency rates or limb-salvage rates between genders. Furthermore, while women with limb-threat, diabetes, and advanced TASC severity lesions were at increased risk of failure overall, there were no differences between women and men with these characteristics. CONCLUSIONS: Percutaneous infrainguinal revascularization is a very effective modality in women with lower extremity occlusive disease. Although women in this sample were more likely to present with limb-threat than men, patency and limb-salvage rates were equivalent between genders, even in high-risk subsets such as diabetics or those with lesions of increased TASC severity.

Minimally invasive retrieval of a dislodged Wallstent endoprosthesis after an endovascular abdominal aortic aneurysm repair.

Endovascular abdominal aortic aneurysm repair (EVAR) is being performed more frequently in patients with concomitant iliac artery occlusive disease. We report a case of a 70-year-old male status post angioplasty and stenting of bilateral iliac arteries for occlusive disease who subsequently underwent EVAR for a rapidly expanding abdominal aortic aneurysm (AAA). One month after the placement of the endograft, it was discovered that the previously placed Wallstent had been dislodged during the endovascular abdominal aortic aneurysm repair. Minimally invasive retrieval using an Amplatz Goose Neck Snare was successful in recovering the stent. This case underscores the danger of performing EVAR in the setting of prior iliac artery stenting and the potential complications that may ensue.

Lesion severity and treatment complexity are associated with outcome after percutaneous infra-inguinal intervention.

OBJECTIVES: Percutaneous revascularization has become increasingly utilized for the treatment of lower extremity ischemia. Patients with limb-threat have been shown to be at increased risk of failure, although the reasons for this remain unclear. This study analyzed factors associated with percutaneous treatment failure, focusing specifically on lesion characteristics and treatment complexity. METHODS: We retrospectively reviewed percutaneous infra-inguinal interventions performed for peripheral occlusive disease between 2002 and 2005 using a prospectively maintained database. Lesion characteristics were assessed by angiography, and lesions were graded according to the TransAtlantic InterSociety Consensus (TASC) criteria. Patency was expressed by Kaplan-Meier method and compared by log-rank analysis. Multivariate Cox-regression analysis was used to assess significant factors on univariate analysis. Mean follow-up was 11.8 months. RESULTS: A total of 324 interventions for claudication (55.8%), rest pain (18.4%), or tissue loss (25.8%) were analyzed, including 284 primary interventions and 40 re-interventions in 258 patients (mean age 72.1 +/- 10 years, 51.0% male). TASC lesion grades included: A (4.9%), B (29.3%), C (37.7%), and D (28.1%). Isolated single-level interventions (femoral, popliteal, or tibial) were performed in 38.9%, while two-level interventions were performed in 46.2% and three-level interventions in 14.9%. Overall primary patency (+/- SD) at 6, 12, and 18 months was 87 +/- 2%, 66 +/- 2% and 59 +/- 4%, respectively. Secondary patency at 6, 12, and 18 months was 89 +/- 2%, 76 +/- 3%, and 69 +/- 5%. One-year limb salvage rate (limb-threat patients) was 85 +/- 3%. Limb-threatening ischemia as the indication for intervention was most highly associated with failure of both primary and secondary patency and was associated with four indicators of lesion severity and treatment complexity, including increasing TASC grade, multilevel intervention, tibial intervention, and reduced tibial outflow. One-year primary patency was inversely correlated with TASC severity (TASC A-C: 67 +/- 6%, D: 61 +/- 4%; P < .05), multilevel intervention (76 +/- 5% and 49 +/- 9% for single vs multilevel, P = .002), distal interventions (74 +/- 5% and 57 +/- 7% for femoral vs tibial, P < .05), and decreased tibial runoff (83 +/- 6% and 52 +/- 6% for three- vs < three-vessels, P < .02). No differences in secondary patency or limb-salvage rates existed for these lesion- and treatment-related variables. Multilevel intervention and tibial intervention remained significant independently associated with primary patency on multivariate analysis. CONCLUSIONS: Patients with limb-threatening ischemia are at increased risk of initial failure compared with claudicants, likely as a result of the increased prevalence of advanced lesion severity and treatment complexity, which are associated with decreased primary patency. However, this finding did not extend to secondary patency or limb-salvage in the overall patient population. Although additional studies with longer follow-up are needed, these findings argue that percutaneous intervention may still be considered as a primary treatment modality with the understanding that these patients may have higher re-intervention rates and may ultimately require salvage open surgical bypass for persistent failures of percutaneous therapy.

Influence of type II endoleak volume on aneurysm wall pressure and distribution in an experimental model.

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.

Discontinuous, staccato growth of abdominal aortic aneurysms.

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.

Fate of collateral vessels following subintimal angioplasty.

PURPOSE: To evaluate the fate of collateral vessels adjacent to and within the target lesion following subintimal angioplasty (SIA). METHODS: Pre and postprocedural angiograms were reviewed for 29 patients undergoing SIA of the lower extremity arteries over a 3-year period. The number of patent collateral vessels

Predicting aneurysm enlargement in patients with persistent type II endoleaks.

OBJECTIVE: The clinical significance of type II endoleaks is not well understood. Some evidence, however, indicates that some type II endoleaks might result in aneurysm enlargement and rupture. To identify factors that might contribute to aneurysm expansion, we analyzed the influence of several variables on aneurysm growth in patients with persistent type II endoleaks after endovascular aortic aneurysm repair (EVAR). METHODS: In a series of 348 EVARs performed during a 10-year period, 32 patients (9.2%) developed type II endoleaks that persisted for more than 6 months. Variables analyzed included those defined by the reporting standards for EVAR (SVS/AAVS) as well as other endoleak characteristics. Univariate, receiver operating characteristic curve, and Cox regression analyses were used to determine the association between variables and aneurysm enlargement. RESULTS: The median follow-up period was 26.5 months (range, 6-88 months). Thirteen patients (41%) had aneurysm enlargement by 5 mm or more (median increase in diameter, 10 mm), whereas 19 (59%) had stable or shrinking aneurysm diameter. Univariate and Cox regression analyses identified the maximum diameter of the endoleak cavity, ie, the size of the nidus as defined on contrast computed tomography scan, as a significant predictor for aneurysm enlargement (relative risk, 1.12; 95% confidence interval, 1.04-1.19; P =.001). The median size of the nidus was 23 mm (range, 13-40 mm) in patients with aneurysm enlargement and 8 mm (range, 5-25 mm) in those without expansion (Mann-Whitney U test, P <.001). Moreover, receiver operating characteristic curve and Cox regression analyses showed that a maximum nidus diameter greater than 15 mm was particularly associated with an increased risk of aneurysm enlargement (relative risk, 11.1; 95% confidence interval, 1.4-85.8; P =.02). Other risk factors including gender, smoking history, hypertension, need of anticoagulation, aneurysm diameter, type of endograft used, and number or type of collateral vessels were not significant predictors of aneurysm enlargement. CONCLUSIONS: In patients with persistent type II endoleaks after EVAR, the maximum diameter of the endoleak cavity or nidus is an important predictor of aneurysm growth and might indicate the need for more aggressive surveillance as well as earlier treatment.

Delayed open conversion following endovascular aortoiliac aneurysm repair: partial (or complete) endograft preservation as a useful adjunct.

OBJECTIVES: The purpose of this study was to review our experience with delayed open conversion (>30 days) following endovascular aortoiliac aneurysm repair (EVAR) and to introduce the concept and advantages of endograft retention in this setting. METHODS: From January 1992 to January 2003, a total of 386 EVARs using a variety of endografts were successfully deployed. Eleven (2.8%) patients required delayed conversion to open repair at an average of 30 months (range, 10-64). Data from all patients undergoing both EVAR and open conversion were prospectively collected. RESULTS: EVARs were performed using grafts made by Talent (4), Vanguard (2,) AneuRx (1), and Surgeon (4). Conversion to open repair (9 transabdominal, 1 retroperitoneal, 1 transabdominal plus thoracotomy) was performed for aneurysm rupture in 7 patients (4 type 1 endoleak, 2 type 2 endoleak, 1 aortoenteric fistula) and aneurysm enlargement in 4 patients (1 type 1 endoleak, 1 type 2 endoleak, 1 type 3 endoleak, 1 endotension). Patients with aneurysm rupture were treated on an emergent basis. Complete removal of the endograft with supraceliac cross-clamping was performed in two cases. One patient (rupture) did not survive the operation, and one patient (aortoenteric fistula) died 2 weeks postoperatively. In the remaining nine cases, the endograft was either completely (1) or partially (6) removed, or left in situ (2). Supraceliac balloon control (2), supraceliac clamping (1), suprarenal clamping (1), or infrarenal clamping (5) was used in these cases. All nine of these patients survived the operation. In one procedure in which the endograft was left intact (endotension), repair was accomplished by exposing the endograft and by placing a standard tube graft over it as a sleeve. In the second procedure in which the graft was left in situ (rupture), the graft was well incorporated, and bleeding lumbar arteries were oversewn and the sac was closed tightly over the endograft. In the remaining 7 cases, the endograft was transected and the proximal portion only (6) or the proximal and distal portions (1) were excised. All surviving patients continue to do well and remain without complications associated with the endograft remnant at a mean follow-up of 22 months (range, 3-56) from the time of open conversion and 46 months (range, 10-73) from the time of original EVAR. CONCLUSIONS: Open repair in the setting of a long-standing endograft offers several unique technical challenges but can be successfully accomplished in most patients. Preservation of all or part of the endograft is possible in many patients. This technique simplifies the operative approach and is preferred over complete endograft removal if possible.

Does transrenal fixation of aortic endografts impair renal function?

OBJECTIVES: Transrenal fixation (TFX) of aortic endografts is thought to increase the risk for renal infarction and impaired renal function. We studied the late effects of TFX on renal function and perfusion. METHODS: Of 189 patients with commercial aortic endografts, which we inserted between 1995 and 2002, we reviewed data for 130 patients (112 men, 18 women) with available creatinine (Cr) concentration and contrast enhanced computed tomography (CT) scans preoperatively and 1 to 97 months after the procedure. Of the 130 patients, 69 patients had TFX and 61 patients had infrarenal fixation (IFX). Both groups were physiologically comparable. Average age was 76 +/- 8 years for patients with TFX and 75 +/- 8 years for patients with IFX. Presence of renal infarct or renal artery occlusion was determined by nephrograms on serial contrast-enhanced CT scans. RESULTS: Mean follow-up was 17 +/- 16 months (range, 1-54 months) for TFX and 21 +/- 21 months (range, 1-97 months) for IFX. Mean serum Cr concentration increased significantly during long-term follow-up in both groups (TFX, 1.3 +/- 0.5 mg/dL to 1.5 +/- 0.8 mg/dL, P <.01; IFX, 1.3 +/- 0.7 mg/dL to 1.4 +/- 0.8 mg/dL, P <.03). Creatinine clearance (CrCl) similarly decreased over long-term follow-up in both groups (TFX, 53.3 +/- 17.7 mL/min/1.73 m(2) to 47.9 +/- 16.2 mL/min/1.73 m(2), P <.01; IFX, 58.1 +/- 22.7 mL/min/1.73 m(2) to 53.1 +/- 23.4 mL/min/1.73 m(2), P <.02). There were no significant differences in the increase in Cr concentration (P =.19) or decrease in CrCl (P =.68) between TFX and IFX groups. Small renal infarcts were noted in four patients (5.8%) in the TFX group and one patient (1.6%) in the IFX group. No increase in Cr concentration or decrease in CrCl was noted in any patient with a renal infarct. Postoperative renal dysfunction developed in 7 of 69 patients (10.1%) in the TFX group and 7 of 61 patients (11.5%) in the IFX group. There were no statistically significant differences between groups with respect to number of patients with new renal infarcts (P =.37) or postoperative renal dysfunction (P =.81). CONCLUSION: There is a slight increase in serum Cr concentration and decrease in CrCl after aortic endografting. However, there was no significant difference in these changes between patients with TFX and IFX. Although TFX may produce a higher incidence of small renal infarcts, these do not impair renal function. Thus our midterm results suggest that TFX can be performed safely, with no greater change in renal function than observed after IFX.

Patency rates of femorofemoral bypasses associated with endovascular aneurysm repair surpass those performed for occlusive disease.

PURPOSE: To evaluate the patency rates of femorofemoral grafts performed in conjunction with aortomonoiliac or aortomonofemoral (AMI/F) endografts. METHODS: Over the past 8 years, 110 patients (98 men; mean age 77+/-7 years, range 57-90) underwent aortoiliac aneurysm repair with an AMI/F endograft. Follow-up data in these patients were prospectively collected for a mean 2.3 years (range 1-68 months). RESULTS: There were 2 early (<7 days) AMI/F endograft thromboses with secondary femorofemoral graft occlusion. In both patients, patency of all grafts was restored by thrombectomy plus stenting of the endograft. Three late (4, 5, and 10 months) AMI/F endograft thromboses led to femorofemoral graft failure; 2 were successfully treated, but the third patient refused further intervention. No femorofemoral bypass failed in the absence of AMI/F endograft thrombosis. There were no femorofemoral graft infections. Four-year life-table primary and secondary patency rates were 95% and 99%, respectively. CONCLUSIONS: Femorofemoral bypasses with AMI/F endografts for aneurysmal disease are durable procedures and have better patency than femorofemoral grafts used to treat occlusive disease. Femorofemoral bypass patency rates alone are not a disadvantage of aortomonoiliac endografts.