Mark F. Fillinger MD, for the Pythagoras Investigators
Dartmouth-Hitchcock Medical Center, Lebanon, NH.
OBJECTIVES: The Pythagoras study is the first clinical trial to evaluate outcomes for EVAR in highly-angulated infrarenal aortic necks (>60 degrees).
METHODS: The Aorfix endograft (Lombard Medical) is a highly-conformable modular nitinol/polyester device designed for infrarenal or transrenal fixation. The US trial enrolled 205 patients on intent to treat. Control patients undergoing open repair were also
enrolled (n=76), and added to a meta-analysis of control patients from US EVAR clinical trials serving as the primary control group.
RESULTS: Demographics and comorbidities were similar for the EVAR group and open control patients with the exception of age (EVAR 75 ± 8, vs 69 ± 2 years, p<0.05), CHF (EVAR 14% vs 4% p=0.029), tobacco use (EVAR 97% v 88% p=0.012), and neck angle (EVAR all 72 ± 22, EVAR high angle 83 ± 15, vs Open 48 ± 22 degrees, p<0.05), which were all more severe in the EVAR group. There was a trend toward more females in the EVAR arm (29%) as compared to the control arm (20%), a difference that was significant for the subjects with highly angled necks ≥60° ( 35% v 20%; p=0.015). Sac diameter (5.8 cm in each group) and other anatomic variables were similar. Operative data favored the test group for procedure duration, EBL, and hospital length of stay (all p<0.05). Outcomes for 1 month and 1 year compared to the SVS control group are shown in the Table (SVS MAEs = Major Adverse Events as defined by the SVS).
CONCLUSIONS: The Pythagoras US Clinical Trial of the Aorfix endograft is the first EVAR clinical trial to include highly-angulated infrarenal aortic necks (>60 degrees). Despite significant predictors of worse short and long-term outcomes (female gender, CHF, neck angle), MAEs and other pertinent outcomes were either better or similar to open repair, and similar to trials with less severe anatomy. The results suggest a potential less invasive option for patients with highly angulated neck anatomy who would otherwise have no endovascular options.
AUTHOR DISCLOSURES: M. Fillinger, Nothing to disclose.
Updated May 2012