The Italian trial of endovascular AAA exclusion using the Parodi endograft

Systematic Review and Meta-analysis of 12 Years of Endovascular Abdominal Aortic Aneurysm Repair

BACKGROUND

Endovascular repair (ER) of abdominal aortic aneurysm (AAA) is a new technique, and reported rates of endoleak, conversion to open repair, rupture and mortality vary widely. The aim of this study was to estimate these rates from the published data, and examine how this has changed as more patients have undergone ER.

METHODS

A systematic review and meta-analysis of publications identified through searches of the electronic databases EMBASE and Medline. All publications quoting endoleak, conversion to open repair, rupture and mortality rates for a series of patients undergoing ER were included.

RESULTS

163 studies pertaining to 28,862 patients undergoing ER were identified as relevant for the review and meta-analysis. The pooled estimate for operative mortality was 3.3% (95% confidence interval 2.9 to 3.6%). The pooled estimate for type 1 endoleaks was 10.5% (95% confidence interval 9.0 to 12.1%), with an annual rate of 8.4% (95% confidence interval 5.7% to 12.2%). The pooled estimate of type 2,3 and 4 endoleaks was 13.7% (95% confidence interval 12.3 to 15.3%), with an annual rate of 10.2% (95% confidence interval 7.4% to 14.1%). The pooled estimate for primary conversion to open repair was 3.8% (95% confidence interval 3.2 to 4.4%), and for secondary conversion to open repair 3.4% (95% confidence interval 2.8 to 4.2%). The pooled estimate for post-operative rupture was 1.3% (95% confidence interval 1.1 to 1.7%), with an annual rupture rate of 0.6% (95% confidence interval 0.5% to 0.8%). Multivariate meta-regression analysis showed that rates of operative mortality, post-operative rupture and total number of endoleaks all fell significantly (p<0.05) over time.

CONCLUSIONS

This study demonstrates a low mortality and a gradual reduction in vascular morbidity and mortality associated with endovascular repair since it was first introduced.

Immediate and late explantation of endovascular aortic grafts: the endovascular technologies experience

PURPOSE

The morbidity and clinical outcome of the failure to successfully repair an abdominal aortic aneurysm with Endovascular Technologies (EVT) grafts, resulting in explantation of the device, was assessed.

METHODS

The records of all patients worldwide undergoing attempted endovascular repair with EVT devices from February 1993 to October 1997 were retrospectively reviewed. Of 669 patients, 19 (3%) were converted to open procedure with immediate explantation during the initial attempt at endovascular repair, and 27 patients (4%) required explantation at a later date, ranging from 1 day to 40 months. The incidence, morbidity, mortality, and effect on clinical outcome were evaluated.

RESULTS

Causes of immediate conversion with explantation were: inaccurate deployment of the proximal or distal attachment systems (11 of 19; 58%); twists in the system (3 of 19; 16%); mechanism malfunction during deployment (4 of 19; 21%); and an aortic tear (1 of 19; 5%). Among the 27 patients undergoing late explantation, 20 (74%) did so because of persistent endoleaks. Three cases (11%) were performed because of aneurysm rupture, three (11%) because of graft occlusion, one because of aortic dissection (4%), and one (4%) because of graft migration into the aneurysm sac. The overall perioperative mortality rate was 11% (2 of 19) for immediate explantation and 7% (2 of 27) for late explantation. The average length-of-stay was 11 days for immediate explantation and 14 days for late explantation (NS). Complications included myocardial infarction (4%), pulmonary insufficiency (13%), wound infection (4%), and permanent renal failure (2%). There were no significant differences in the incidence rates of these complications between immediate and late explants. No cases of limb loss occurred. Median American Society of Anesthetists (ASA) classification was 3, and there was no correlation between ASA classification and mortality rate. Average operating time was 374 minutes for immediate explantation (including the time for the failed endovascular procedure) and 185 minutes for late explantation.

CONCLUSION

Immediate and late explantation are infrequent events, occurring in 3% and 4%, respectively, of attempted EVT endovascular aortic stent placements. The mortality rate was higher for both immediate (11%; P <.05) and late (7%; NS) explantation when compared with the mortality rate of all patients undergoing EVT aortic endograft placement (1.5%). There does not appear to be increased long-term morbidity among patients undergoing successful explantation. Early recognition of the need to convert to open procedure, device improvement, and increased operator experience should continue to minimize the incidence of immediate and late explantation and their associated complications.

Endovascular grafting for abdominal aortic aneurysms

Despite the initial success of endovascular grafts in a very difficult patient population, many problems remain. These procedures are often time-consuming and quite complicated, requiring the close cooperation of an experienced team of vascular surgeons and interventional radiologists. Access may be difficult through occluded, stenotic, and tortuous vessels. Inadequate graft deployment may result in arterial rupture or graft migration, which could potentially lead to acute occlusion of the renal or iliac arteries. Occlusion of the inferior mesenteric artery may result in ischemic colitis. Also, endovascular grafts may fail to exclude an aneurysm from systemic arterial blood pressure, not protecting the patient against impending rupture, and embolization and thrombosis are ever-present dangers. Concerns have been raised regarding radiation exposure and intravenous contrast loads used during these procedures. Clearly, more experience must be gained and technologic advancements made before the use of these devices becomes commonplace, something that may not be too far off in the future.

Aortoenteric fistula caused by a ruptured stent-graft: a case report

PURPOSE

To report a case of aortoenteric fistula secondary to endovascular abdominal aortic aneurysm (AAA) exclusion using the Stentor bifurcated endovascular graft.

METHODS AND RESULTS

Seventeen months after a successful endovascular AAA procedure, a male patient developed upper gastrointestinal bleeding. An aortoenteric fistula was diagnosed. At operation, the endograft fabric was found to be ruptured in an area of suture disruption between the nitinol stents. Coincidentally, a pre-existing inflammatory process might have caused adhesions between the bowel and the aortic wall, predisposing to fistula formation. The patient recovered after placement of a conventional aortic graft.

CONCLUSIONS

Suture disruption between the internal support stents is a recognized complication in the first-generation Stentor device. Although the case described here is probably not typical of the consequences of this sequela, it does reinforce the need for continual periodic imaging to check for signs of graft disruption in Stentor endografts.

Experience with the Stentor endograft at four Italian centers

PURPOSE

To report the outcome of an Italian multicenter trial of endovascular abdominal aortic aneurysm (AAA) exclusion using the Stentor device.

METHODS

Between April 1995 and July 1996, 66 patients (63 men; average age 69 years, range 53 to 84) with infrarenal AAAs meeting the inclusion criteria were enrolled. The average diameter of the aneurysm was 4.6 cm (range 4.2 to 7). Three (4.5%) of the 66 AAAs were anastomotic aneurysms.

RESULTS

Sixteen (25%) tubular and 50 (76%) bifurcated endograft procedures were attempted; 4 (6.1%) were converted and 1 terminated owing to technical faults with the bifurcated graft's second limb. One tube graft was too short and failed to exclude an anastomotic aneurysm. Sixty (91%) endograft procedures were completed successfully. Six (9.1%) vascular complications occurred, three in one patient who subsequently died of pulmonary embolism 72 hours postoperatively (1.5% mortality). There were four (6.1%) proximal endoleaks; two sealed spontaneously in < 1 month, and a third was converted (7.6% conversion rate). The fourth is being observed. Clinical success (aneurysm exclusion with no death or endoleak) at 30 days was 86.3% (57/66). In the 23-month follow-up of 57 eligible patients, 2 patients died of unrelated causes and 1 graft limb thrombosed, requiring a crossover femoral bypass. One patient was converted to surgical repair at 5 months postoperatively when increasing aneurysm size signaled an undisclosed endoleak (1.8% late conversion rate). Five other secondary endoleaks were treated with endovascular techniques.

CONCLUSIONS

The Stentor was technically feasible in 10% to 40% of AAA candidates in this study, although deployment of the second limb was problematic in the bifurcated device. Introduction of the second-generation Vanguard endograft brought this study to an end.