Jacob Buth

Early complications and endoleaks after endovascular abdominal aortic aneurysm repair: Report of a multicenter study

OBJECTIVE The aim of this study was the identification of risk factors for adverse events and the assessment of the early success rate in 1554 patients with abdominal aortic aneurysms (AAAs) who underwent treatment with endovascular technique between January 1994 and March 1999. For this purpose, the clinical and procedural data were correlated with observed complications and endoleaks. METHODS The data were collected from 56 European centers and submitted to a central registry. Patient characteristics, aortoiliac anatomic features, operative technical details, types of devices used, and experience of the teams of physicians were correlated with the occurrence of complications and endoleaks. The technical success rate was assessed according to the Society for Vascular Surgery/International Society for Cardiovascular Surgery, North American Chapter, guidelines. For the assessment of correlations between risk factors and adverse events, a multivariate logistic regression analysis was used. RESULTS The operative complications were grouped into three categories: failure to complete the procedure (39 patients, of which 27 underwent a conversion to an open AAA repair; 2.5%); device-related or procedure-related complications (149 patients; 10%); and arterial complications (51 patients; 3%). The most important risk factors for failure to complete the procedure included an aneurysm diameter of 60 mm or more and the need for adjuvant procedures. The factors that predicted device-related and arterial complications were the experience of the team with endovascular AAA treatment and the need for adjuvant procedures. Forty patients (2.6%) died within 30 days after operation. American Society of Anesthesiologists III and IV operative risk classification results predicted higher mortality rates than did American Society of Anesthesiologists operative risk classification I and II results. The patients who underwent operation in 1994, the first year documented in this registry, and those who required adjuvant procedures also had an increased risk of perioperative death. The incidence rate of systemic complications within the first 30 days (279 patients; 18%) was higher in patients aged 75 years or more, in patients with an impaired cardiac status, and in patients considered unfit for an open procedure. An endoleak was detected at the completion of the procedure in 16% of the cases and was still present after 1 month in 9%. The risk factors for primary endoleaks were female gender and age of 75 years and older. The observed technical success rate in this patient series was 72%. CONCLUSION The learning curve of the doctors and the need for adjuvant procedures were independent risk factors of operative device-related and arterial complications. The importance of proper instruction during an institutions initial phase with this treatment is emphasized by these observations. Although the endovascular management of AAAs is less stressful than open surgery, systemic complications were still the most common adverse events during the first postoperative month. These complications were associated with several patient-related factors, including advanced age, impaired cardiac status, and poor general medical condition. These observations may be a guide for improved patient selection for endovascular AAA repair.

Balloon angioplasty combined with primary stenting versus balloon angioplasty alone in femoropopliteal obstructions: A comparative randomized study.

AbstractPurpose: To evaluate whether balloon angioplasty combined with stenting (ST) of symptomatic femoropopliteal disease would provide better results compared with balloon angioplasty alone (BA). Methods: Fifty-one patients were randomized between ST (24 patients) and BA (27 patients). Follow-up comprised clinical and hemodynamic assessment and color-flow duplex ultrasound examinations. Results: Residual stenosis (≥ 30% diameter reduction) occurred in three BA patients, but not in the ST patients. By life-table analysis the cumulative rate of clinical and hemodynamic success after 1 year with ST was 74% (SE 9%) and for those with BA 85% (SE 7%) (p= 0.25). The primary patency at 1 year assessed by color-flow duplex ultrasound was 62% (SE 9%) for ST-treated patients and 74% (SE 8%) for BA patients (p= 0.22). Occlusion occurred in five ST patients (21%) compared with two BA patients (7%). Conclusion: ST does not improve clinical and hemodynamic outcome compared with BA. Moreover, the occlusion rate in ST-treated patients is higher.

Influence of Severe Infrarenal Aortic Neck Angulation on Complications at the Proximal Neck following Endovascular AAA Repair: A EUROSTAR Study

Purpose: To examine the influence of severe infrarenal neck angulation (SNA) on complications after endovascular repair of abdominal aortic aneurysm (AAA). Methods: From October 1996 to January 2006, 5183 patients who underwent endovascular aneurysm repair using a Talent, Zenith, or Excluder stent-graft were enrolled into the EUROSTAR registry. Incidence of proximal type I endoleak, stent-graft migration, proximal neck dilatation, aneurysm rupture, secondary interventions, and all-cause and aneurysm-related mortality were compared between patients with and without severe infrarenal neck angulation (>60° angle between the infrarenal aortic neck and the longitudinal axis of the aneurysm). Results: In the short term (before discharge), proximal type I endoleak (OR 2.32, 95% Cl 1.60 to 3.37, p<0.0001) and stent-graft migration (OR 2.17, 95% Cl 1.20 to 3.91, p=0.0105) were observed more frequently in patients with SNA. Over the long term, higher incidences of proximal neck dilatation ≥4 mm (HR 1.26, 95% Cl 1.11 to 1.43, p=0.0004), proximal type I endoleak (HR 1.80, 95% Cl 1.25 to 2.58, p=0.0016), and need for secondary interventions (HR 1.29, 95% Cl 1.00 to 1.67, p=0.0488) were seen in patients with SNA. All-cause mortality, aneurysm-related mortality, and rupture of the aneurysm were similar in patients with and without severe neck angulation. In the subgroup of patients with an Excluder endograft, proximal endoleak at the completion angiogram (OR 4.49, 95% Cl 1.31 to 15.32, p=0.0166) and long-term proximal neck dilatation (HR 1.67, 95% Cl 1.20 to 2.33, p=0.0026) were more frequently observed in patients with SNA. In the Zenith subgroup, proximal endoleak at the completion angiogram (OR 2.62, 95% Cl 1.49 to 4.63, p=0.0009) and proximal stent-graft migration before discharge (OR 2.34, 95% Cl 1.06 to 5.19, p=0.0353) were more common in patients with SNA. In the Talent subgroup, long-term proximal endoleak (HR 2.09, 95% Cl 1.27 to 3.44, p=0.0036), proximal neck dilatation (HR 1.29, 95% Cl 1.05 to 1.60, p=0.0168), and secondary interventions (HR 1.54, 95% Cl 1.05 to 2.24, p=0.0259) were more frequently observed in patients with SNA. Conclusion: Severe infrarenal aortic neck angulation was clearly associated with proximal type I endoleak, while the relationship with stent-graft migration was not clear. Excluder, Zenith, and Talent stent-grafts perform well in patients with severe neck angulation, with only a few differences among devices.

Collected world and single center experience with endovascular treatment of ruptured abdominal aortic aneurysms

Background:Case and single center reports have documented the feasibility and suggested the effectiveness of endovascular aneurysm repair (EVAR) of ruptured abdominal aortic aneurysms (RAAAs), but the role and value of such treatment remain controversial. Objective:To clarify these we examined a collected experience with use of EVAR for RAAA treatment from 49 centers. Methods:Data were obtained by questionnaires from these centers, updated from 13 centers committed to EVAR treatment whenever possible and included treatment details from a single center and information on 1037 patients treated by EVAR and 763 patients treated by open repair (OR). Results:Overall 30-day mortality after EVAR in 1037 patients was 21.2%. Centers performing EVAR for RAAAs whenever possible did so in 28% to 79% (mean 49.1%) of their patients, had a 30-day mortality of 19.7% (range: 0%–32%) for 680 EVAR patients and 36.3% (range: 8%–53%) for 763 OR patients (P < 0.0001). Supraceliac aortic balloon control was obtained in 19.1% ± 12.0% (±SD) of 680 EVAR patients. Abdominal compartment syndrome was treated by some form of decompression in 12.2% ± 8.3% (±SD) of these EVAR patients. Conclusion:These results indicate that EVAR has a lower procedural mortality at 30 days than OR in at least some patients and that EVAR is better than OR for treating RAAA patients provided they have favorable anatomy; adequate skills, facilities, and protocols are available; and optimal strategies, techniques, and adjuncts are employed.

Rupture of infra-renal aortic aneurysm after endovascular repair: a series from EUROSTAR registry.

OBJECTIVES Although small, the risk of rupture after EVAR remains a major concern. The aim of this study was to identify mechanisms of late aneurysm rupture after endovascular repair. METHODS Patients who suffered a proven aneurysm rupture after EVAR were identified from the EUROSTAR (European Collaborators on Stent-graft Techniques for Abdominal Aortic Aneurysm Repair) registry. Complications preceding rupture were studied to identify common patterns and possible mechanisms of late rupture. RESULTS A rupture was documented in 34 patients resulting in death of 21 (62%). Adverse events documented during previous follow-up in these patients included endoleak (30%), migration (18%), limb occlusion (12%) and kinking (12%). The findings at time of rupture were documented in 24 patients and including endoleak: Type III (10), Type I (9), Type II (1); stent-graft disintegration (2) and migration (3). Aneurysm diameter changes could be ascertained in 24 patients and had increased in only seven. CONCLUSION The importance of graft-related endoleak, stent-graft disintegration and migration in the causation of aneurysm rupture was confirmed. Poor compliance with follow-up schedule was also identified as a common feature. However, the absence of complications in some patients, who attended regularly for follow-up, highlights the difficulty of predicting rupture after EVAR.

Impact of a color-flow duplex surveillance program on infrainguinal vein graft patency: A five-year experience

PURPOSE AND METHODS The contribution of color-flow duplex surveillance to improving vein graft patency was evaluated in two patient groups after 201 infrainguinal bypass procedures were performed during a 5-year period. Incidence of revision procedures and the primary and assisted primary patency rates were compared for 160 bypass grafts monitored during the first 2 years by use of color-flow duplex scanning of the vein graft and adjacent arterial segments (color-flow surveillance group) versus 41 bypass grafts monitored by use of clinical assessment alone (clinical follow-up group). Only grafts that were patent after the first postoperative month are considered. RESULTS The two groups were comparable with regard to most of the pertinent clinical factors. Stenotic lesions were identified in 58 bypass grafts, and severity was determined by use of intraarterial digital subtraction angiography. Eighteen bypass grafts with stenoses did not undergo a revision for reasons that were determined by the doctor, the hospital, or the patient. The occlusion rates of revised and nonrevised stenotic grafts were compared for lesions of different severity. None of the grafts for stenoses with 30% to 49% diameter reduction (DR) failed during follow-up. Occlusion occurred in 57% of the nonrevised and 9% of revised grafts (p = 0.047) for stenoses with 50% to 69% DR. Stenoses with 70% or greater DR were associated with graft failure in 100% of nonrevised bypasses and in 10% of revised grafts (p = 0.004). The assisted primary patency rate was higher in grafts that underwent color-flow surveillance compared with grafts with that underwent clinical follow-up (3-year patency rates of 91% and 72%, respectively; p = 0.004). The independent correlation of color-flow surveillance with higher patency rates was demonstrated in a proportional hazard analysis. The relative risk (probability of occlusion) in color-flow surveillance grafts is less than one third of the relative risk in bypass grafts that underwent clinical follow-up. CONCLUSIONS We conclude that revision procedures were more optimally used during color-flow surveillance, whereas asymptomatic stenotic graft lesions are missed with clinical follow-up, which results in a higher percentage of graft failures. Overall graft patency rates can be improved with use of color-flow duplex surveillance and repair of significant stenotic lesions.

Influence of Infrarenal Neck Length on Outcome of Endovascular Abdominal Aortic Aneurysm Repair

Purpose: To evaluate the influence of the infrarenal neck length on clinical outcome after endovascular abdominal aortic aneurysm repair (EVAR). Methods: Data were analyzed from 3499 patients enrolled in the EUROSTAR registry between January 1999 and April 2005 who underwent EVAR with a Talent or Zenith endograft and had detailed morphological data recorded. The study cohort was divided into 3 groups according to infrarenal neck length: >15 mm (reference group A, n=2822), 11 to 15 mm (group B, n=485), and ≤10 mm (group C, n=192). Uni- and multivariate analyses were performed to evaluate differences in clinical outcomes among the study groups. Results: After correction for confounders, proximal type I endoleak within 30 days occurred in 10.9% of group C compared to 2.6% of group A (OR 4.46, 95% CI 2.61 to 7.61). Within 48 months of follow-up (median 12 months), the incidence of proximal endoleaks was higher in groups B (9.6%; HR 1.98, 95% CI 1.16 to 3.38) and C (11.3%; HR 2.132, 95% CI 1.17 to 4.60) compared to group A (3.4%). Conclusion: Our study indicates that endovascular treatment of abdominal aortic aneurysms with infrarenal neck length <15 mm is associated with significantly increased risk of short- and midterm proximal endoleaks after EVAR. The greater risk of proximal endoleaks should be weighed against the risks of alternative treatment modalities.

The significance and management of different types of endoleaks

Development of endovascular abdominal aortic aneurysm repair (EVAR) has been accompanied by previously unencountered complications. The most challenging but least understood of these complications is the incomplete seal of the endovascular graft (endoleak), a phenomenon that has a variety of causes. An important consequence of endoleakage may be persistent pressurization of the aneurysm sac, which may ultimately lead to post-EVAR rupture. Data of 110 European centers were recorded in a central database (EUROSTAR). Patient, anatomic characteristics, and operative and device details were correlated with the occurrence of different types of endoleaks. Outcome events during follow-up, particularly expansion of the aneurysm, incidence of conversion to open repair, and post-EVAR rupture were assessed in the different categories of endoleaks and in a group of patients without any endoleak. Type I and III endoleak were associated with an increased frequency of open conversions or risk of rupture of the aneurysm. Device-related endoleaks also correlated with an increased need for secondary interventions. These types of endoleaks need to be treated without delay, and when no other possibilities are present, an open conversion to avert the risk of rupture should be considered. Type II endoleaks do not pose an indication for urgent treatment. However, they may not be harmless, because there was a frequent association with enlargement of aneurysm and reinterventions. Our findings suggest that more frequent surveillance examinations are indicated than in patients without collateral endoleak. The indication for intervention is primarily dictated by documented expansion of the aneurysm.

The Need for Clinical Trials of Endovascular Abdominal Aortic Aneurysm Stent-Graft Repair: The EUROSTAR Project

EUROSTAR(EUROpean collaborators on Stent-graft Techniques for abdominal aortic Aneurysm Repair) was established for the purpose of combining and studying data on endovascular abdominal aortic aneurysm (AAA) repair. EUROSTAR is independent of any commercial interest and has as its ultimate goal an independent, scientifically reliable assessment of endovascular AAA grafting. A standardized case record form is used for data collection and transmission, and the database is maintained in a central registry office. A comprehensive set of clinical, imaging, technical, and laboratory data obtained at initial admission and follow-up are recorded; these data are analyzed periodically and reports generated on the collated experience. As a first priority, an observational study without controls was initiated in July 1996 to address the issues of procedural safety, device durability, and long-term effect upon the aneurysms. Several ancillary studies have been initiated, including a “Retrieval and Analysis Study” for the evaluation of explanted devices. While a randomized study does not seem feasible at present, this may be organized at the appropriate time when the devices and techniques become more standardized.

Risk-adjusted outcome analysis of endovascular abdominal aortic aneurysm repair in a large population: how do stent-grafts compare?

Purpose: To compare differences in the applicability and incidence of postoperative adverse events among stent-grafts used for repair of infrarenal aortic aneurysms. Methods: An analysis of 6787 patients from the EUROSTAR Registry database was conducted to compare aneurysm morphological features, patient characteristics, and postoperative events for the AneuRx, EVT/Ancure, Excluder, Stentor, Talent, and Zenith devices versus the Vanguard device (control) and each other. Annual incidence rates of complications were determined, and risks were compared using the Cox proportional hazards analysis. Results: The annual incidence rates were: device-related endoleak (types I and III) 6% (range 4%-10%), type II endoleak 5% (range 0.3%-11%), migration 3% (range 0.5%-5%), kinking 2% (range 1%-5%), occlusion 3% (range 1%-5%), rupture 0.5% (range 0%-1%), and all-cause mortality 7% (range 5%-8%). After adjustment for factors influencing outcome, AneuRx, Excluder, Talent, and Zenith devices were associated with a lower risk of migration, kinking, occlusion, and secondary intervention compared to the Vanguard device. Significant increased risk for conversion (EVT/Ancure) and reduced risk of aneurysm rupture (AneuRx and Zenith) and all-cause mortality (Excluder) were found compared to the Vanguard device. Conclusions: Significant differences exist between stent-grafts of different labels in terms of applicability and complications during intermediate to long-term follow-up. Since each stent-graft has its drawbacks, no single label can be identified as the best. It is reassuring that developments in stent-grafts indeed result in better performance than the early stent-grafts. However, a single device incorporating all the perceived improvements should still be pursued.