Results of an analysis of the data from the EVAR trials were presented by Thomas Wyss, from Bern, Switzerland, who spent a year as vascular research fellow at the Charing Cross Vascular Surgery Research Group, London, UK. The data on secondary ruptures after EVAR, published in the Annals of Surgery in November 2010, were presented at the VEITHsymposium, in New York, USA, and at the Vascular Society of Great Britain and Ireland annual meeting in Brighton, UK.
“The aim of our study was to establish the incidence of secondary rupture after endovascular and open repair and, in a second step, to investigate factors associated with secondary rupture,” Wyss said. In total, 848 elective endovascular repairs and 594 elective open repairs were performed in EVAR 1 and 2.
The main finding of Wyss and colleagues after looking at all endovascular and open repairs performed for up to 10 years in the EVAR trials was that there were no ruptures after open repair. Ruptures after open repair have been documented in the past as in the UK Small Aneurysm Trial.
The EVAR 1 trial aneurysm-related mortality converged at the six-year point, having been significantly higher for open repair at four years. In the latter years of follow-up there had to be an explanation for this relative deterioration in the EVAR group at late stages. “This relative improvement of open repair is due to ruptures after EVAR,” he told delegates.
Wyss et al has demonstrated that 27 ruptures occurred after endovascular repair – 25 in EVAR 1 and two in EVAR 2. A possible explanation for EVAR 2 is that there are so few patients alive towards the end of this follow-up period. The 27 ruptures occurred in three groups – five within 30 days (group A) and the sixth at 32 days.
Wyss recommended that in the future any patients being discharged early must have a pre-discharge CT scan. “We assume that there was a technical problem behind all of group A and the first rupture (32 days) of group B. A change of protocol, to always perform a pre-discharge scan could have revealed problems, which could have been addressed,” he said.
There were four additional sac ruptures which occurred without complications – one failed to attend CT scan follow-up. This left three (11%) which ruptured unexpectedly. The patient and clinician, Wyss said, assumed that all was well and “out of the blue” a rupture occurred. “Fortunately this is rare. But, two out of these three died,” he explained.
The remaining 17 patients (group C) had a cluster of recognisable and known endovascular complications particularly endoleaks with sac expansion, and one patient had migration, in addition.
The mortality from EVAR secondary rupture explains catch-up in EVAR aneurysm-related mortality and the better performance of open repair at later stages in EVAR 1.
Wyss said that the next steps are to “implement a pre-discharge computed tomography scan to reduce peri-operative rupture, confirm the collection and sequence of EVAR complications which predispose to rupture, re-examine the threshold for conversion to open repair and prospectively react to high risk scenarios.”