PROTAGORAS Evaluates Endurant Stent Graft for Patients With Pararenal Pathologic Processes Treated by the Chimney/Snorkel EVAR

December 21, 2015—In the Journal of Vascular Surgery (JVS), Konstantinos P. Donas, MD, et al published findings from the PROTAGORAS study (2016;63:1–7), a midterm evaluation of the Endurant stent graft (Medtronic, plc) as a standard abdominal device for the chimney/snorkel endovascular aortic repair (ch-EVAR).

The investigators stated that the background of the study is that ch-EVAR is gaining greater acceptance in the treatment of pararenal pathologic processes, but that the published experience includes mainly short-term clinical results with combinations of several abdominal devices and types of chimney grafts. 

As summarized in JVS, the investigators analyzed prospectively collected data of high-risk patients with pararenal pathologic processes who underwent ch-EVAR with placement of the Endurant abdominal device between January 2009 and January 2013. The chimney graft intended for use was a balloon-expandable covered stent. Main outcome measures were aneurysm sac regression and chimney graft patency.

A total of 187 snorkel/chimney grafts were successfully placed in 128 patients (mean age, 76.6 years) with technical success of 100%. The mean preoperative proximal neck length and aneurysm size were 4.7 mm and 64.8 mm (range, 48–135 mm), respectively. The postoperative, new neck length after use of chimney grafts was 18.7 ± 6.3 mm, and there was a significant mean aneurysm sac decrease (60.8 mm; 95% confidence interval, 2.036–7.084; P = .001) after a mean radiologic follow-up of 24.6 ± 17.4 months.

Thirty-day mortality and midterm mortality were 0.8% and 17.2%, respectively. Two patients (1.6%) with single chimneys presented with late new onset of type Ia endoleak and underwent additional tube and multiple chimney placement. Primary chimney graft patency was 95.7%. Freedom from chimney graft-related reinterventions was 93.1%, reported the investigators.

The investigators concluded in JVS that standard use of the Endurant abdominal device for ch-EVAR in > 120 patients is associated with high technical success, significant aneurysm sac regression, and low incidence of secondary procedures after 2-year radiologic follow-up. They added that these results will give significant impetus to device selection, facilitating the standardization of technique.