Anaconda™: The Italian Registry. Study protocol and preliminary perioperative results

Aim. Anaconda (TM) is an infrarenal stent-graft for the endovascular treatment (EVAR) of abdominal aortic aneurysms (AAA). The Anaconda (TM) Italian Registry is an observational multicentre registry that started in Italy on March 2009. The aim of this study is to present the registry protocol and to evaluate the interim perioperative results. Methods. Patient data collected covered both retrospective and new cases. The case record forms are divided into preoperative data (population characteristics and clinical data), preoperative morphological data, intraoperative data, perioperative data (30-days from Anaconda (TM) implant) and follow-up record forms. The inclusion criteria are:AAA with a maximum sac diameter >= 5 cm, AAA with rapid expansion, symptomatic AAA or with a contained rupture, aorto-iliac aneurysms, proximal neck length >= 15 mm and diameter of the proximal aortic neck between 16 and 31.5 mm. No exclusion criteria were considered regarding aorto-iliac tortuosity, wall calcification or thrombosis and no exclusion criteria were considered regarding the patients age, comorbidities or life expectancy. Seven postoperative follow-up controls (visit and imaging) were required: at 30-days from the Anaconda (TM) implant, 6 months, 1 year and then annually up to 5 years. The registry is still open to new case enrolment. Results. The reported results reflect the registry cases as at March 15, 2011. At this date, 787 cases were present in the database: 722 (91.7%) were male and 65 (8.3%) female. The mean patient age was 76.6 years with a range between 50 and 94 years. The ASA class was >= 3 in 635 patients (80.6%). The mean aneurysmal sac diameter was 55.73 +/- 9.5 mm. The mean proximal aortic neck length was 26.52 +/- 12.31 mm. Of the 787 patients treated, 11 cases of immediate surgical conversion were reported (1.3%). The overall 30-day mortality rate was 1.2% (10 cases): but 30-day death occurred in 0.9% of successful endograft implants and in 27.2% of surgical conversions (p<0.001). In fourteen cases (1.7%) an iliac leg thrombosis occurred and a native iliac artery thrombosis occurred in only five cases (0.5%). The 30-day overall occurrence of endoleaks was observed in 95 cases (12%): 5 cases of type I proximal endoleak (0.6%), 89 cases of type II endoleak (11.3%) and 1 case of type III endoleak (0.1%). No cases of endograft dislocation were reported. Conclusion. This is an interim report on the study protocol and on the preliminary early results. Presently there are no definitive conclusions, however the perioperative results show that the Anaconda (TM) endograft seems to be safe and effective in the treatment of AAA, even in a high risk cohort of patients. Definitive and long-term results are needed.