A clinical study involving all vascular centres in Switzerland treating leaking aneurysms will try to answer whether the time from diagnosis to intervention is related to operative death from ruptured abdominal aortic aneurysms.
The details of the SWIFT (Swiss ruptured aneurysm favourable transport) study were presented at the CX@LINC symposium in Leipzig in January by Regula von Allmen, Vascular Research Group, Imperial College London, UK.
In 2010, according to the Swiss National Vascular Registry, which included data from 21 of 25 Swiss centres, there were 109 ruptured aneurysm repairs and 611 elective aneurysm repairs in Switzerland. In the registry report, 30-day mortality for ruptured aneurysm was 23.8% in Switzerland. In the UK, for example, the Hospital Episode Statistics show operative mortality rates up to 46% for ruptured abdominal aortic aneurysms, Von Allmen noted. “Why is there an interest in Switzerland? Some excellent results have been reported in this country. Switzerland is a circumscribed country and the centres performing vascular surgery are clearly identified,” she said.
She told delegates that there are great variations between centres in the country. “Reports from Zurich show that 50.2% of the ruptured aneurysm patients are managed by endovascular means and 49.8% by open repair. Zurich reports excellent results for EVAR with a 30-day mortality rate of 13.5%. Open repair has a mortality rate of 32.4%. But if patients look anatomically unsuitable for EVAR, then this may not be a fair comparison between open and endovascular repair. However, when we look at data from Bern, there are only 4% who are treated by endovascular means and the vast majority, 96%, is treated with open repair, and the overall 30-day mortality is 15.3%.
“From this we can see that there are pockets of excellence in the treatment of ruptured abdominal aortic aneurysm in Switzerland. As a consequence, it is claimed by one centre that it is unethical to carry out treatment other than EVAR for ruptured aneurysms, but there are obvious counterclaims for open repair based upon the data from Bern. However, the point is we cannot assume that the surgical method alone holds the key. That is why we feel that there is a need for the SWIFT study, including all the Swiss vascular centres,” she added.
SWIFT will be a prospective, all inclusive, study to be conducted for two years. The hypothesis is that the time from first clinical diagnosis of suspected rupture to the time of beginning the intervention relates to 30-day procedural mortality.
The primary endpoint is 30-day surgical mortality; however, rates for death during transfer and turn down rates with reasons for this will also be reported. Key additional factors are the condition of the patient on arrival at hospital, anatomical features assessed by CT scans, and type of transport.
“So why are Swiss results so good? Is it surgical skills? Is it the method? Is it patient selection? Could it relate to swift transfer?” Von Allmen questioned. “Being a circumscribed country, Switzerland has excellent transport facilities with good roads and helicopter use. For instance, cardiologists have proved that results of treatment of acute coronary episodes improved when the time from diagnosis to catheterisation was reduced, the so-called door-to-balloon time. Can it be the same for ruptured abdominal aortic aneurysms? With the participation of all 25 Swiss centres, we may be able to answer this question.”
Von Allmen will give the talk “The time from diagnosis to the operating suite:SWIFT” at the Charing Cross Symposium on 15 April, London, UK.