Benefit of emergency EVAR remains unclear

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Single center series as well as a Global registry organized by Frank Veith indicate that emergency EVAR can achieve a 20% 30 day mortality compared to a 30 day mortality of 40% open repair. A recent prospective study published by Jean-Pierre Becquemin’s group showed that 61% of patients were anatomically suitable for EVAR and the 30 day mortality was 23.5% in these patients. However, there is a question whether these single center results for emergency EVAR are comparable or whether there has been a selection bias in favour of EVAR. Two small prospective randomized trials have recently been presented which show comparable mortality rates for emergency EVAR and open repair. There now seems to be confusion over the “take home” message regarding the benefit of emergency EVAR and doubts over whether there needs to be a large scale trial to assess the validity of EVAR for ruptured abdominal aortic aneurysms.

The results from two studies conclude that endovascular repair (EVAR) to treat ruptured aortic abdominal aneurysms is a treatment option that should be investigated further. Although there are problems associated with randomization, staffing an emergency-EVAR program and the time associated with arrival and treatment, the ability of EVAR to successfully treat inoperable cases has lead the investigators from both studies to call for large-scale randomized controlled trials to evaluate EVAR as a valid treatment option.

Preliminary results presented at the ESVS annual meeting in Helsinki from the Ruptured EndoVascular Aneurysm Repair (REVAR) trial have, according to lead investigator, Bruce Braithwaite, University Hospital Nottingham, UK, highlighted the need for a large scale, multi-center study to assess the outcomes of patients presenting with ruptured abdominal aortic aneurysms (rAAA) who receive either endovascular aneurysm repair (EVAR) or an open aneurysm repair (OAR).

REVAR is single center, prospective, randomized controlled trial, which compared EVAR with an OAR in patients with a rAAA. Between September 2002 and December 2004, over 100 patients were admitted with suspected rAAA. Patients considered fit for open repair were randomized to EVAR or OAR after consent had been obtained. Some 32 patients were randomized, 14 to EVAR and 18 to OAR. Those in the EVAR group had preoperative spiral computer tomography (CT) angiography to assess suitability.

The primary endpoint of the trial was operative (30-day) mortality, whilst secondary endpoints were moderate or severe operative complications, hospital stay and time between diagnosis and operation. A power calculation required 100 patients to be recruited. A total of four patients died before receiving surgical treatment, one in the EVAR arm, and three in the OAR arm. Following assessment suitability, 12 patients were elected to the EVAR arm and 16 patients to the OAR arm.

The results revealed that 30-day mortality rates was 38.5% (n=12) in the EVAR group and 40% (n=16) in the OAR group. In the intention to treat basis (including per-operative deaths), the results were 43% (n=14) in the EVAR group and 50% (18) in the OAR group.

Moderate or severe operative complications occurred in 77% in the EVAR group and 80% in the OAR group. The median total hospital stay in the EVAR group was 10 days (IQR 6 to 28) and 12 days (IQR 4 to 52) in the OAR group.

Mr Braithwaite reported no significance difference in the median time between diagnosis and operation; 75 (IQR 64 to 126) minutes in the EVAR group and 100 minutes (IQR 48 to 138) in the OAR group.

In addition, Mr Braithwaite noted that no EVAR patients died on the operating table, blood product usage was less in the EVAR group and morbidity was similar (EVAR=77%, OAR=80%).

Following his presentation, Braithwaite said that several valuable lessons had been learnt, most importantly that randomization was possible in an emergency situation and CT scans do not delay treatment. He also commented that only 32% of the patients who presented with rupture were recruited; this will have implications for future trial recruitment numbers. In addition, the mortality rate for EVAR was higher than expected.

At present, the study appears to be seriously under-powered to show a statistically significant difference between the two techniques. If vascular surgeons wish to apply traditional research methods then it may require some 800 patients to be enrolled.

Previously, the New ERA Study, a multicentre study assessing the proportion of patients presenting with a rAAA in whom emergency EVAR is applicable, showed that approximately half the patients presenting with a rAAA were candidates for emergency EVAR.

Results from the New ERA Study showed that EVAR and conventional surgery had a 30-day/in-hospital mortality rate of 35 and 37%, respectively and the three month mortality results were 40% for EVAR vs. 42% for open repair. Jaap Buth, Catharina Hospital, Eindhoven, The Netherlands, lead investigator of the study, said that a randomized study will ultimately be needed to assess whether EVAR is associated with improved survival. However, such a trial should not be organized at the present time, because the availability of endovascular expertise, at least in Continental Europe, during on-call emergency procedures needs to improve.

“If you look at the literature, it’s almost always one to one and a half hours between a patient’s arrival at hospital and the operation time – for any emergency procedure,” Buth said. “We all tend to think the patient will be in theatre 15 minutes after arrival, but this is rarely the case. It should also be understood that there are insufficient endovascular surgeons to staff an emergency-EVAR programme. Most (Continental European) hospitals still have more traditional operating vascular surgeons than endovascular specialists. A lack of endovascular specialists does make it difficult to do EVAR procedures in most patients.”

The New ERA study enrolled patients from 10 participating institutions between January 2003 and September 2004. Data were collected and enrolled in a centralized database for analysis. Thirty-day/ in-hospital outcome was assessed for the entire group as a whole and the EVAR and open repair categories separately. The mortality was not significantly different between patients with endovascular and open aneurysm repair. The study concluded that preferential emergency EVAR is a valid option to treat patients with rAAA.

Braithwaite said that more evidence is necessary to show that EVAR is better than OAR in rAAA. However, based on the available information, future randomized trials need to be larger than expected to show a difference in outcome. He also commented that a registry could be used as an alternative method of analysis.

Rather than attempt to run a large randomized trial, Mr Braithwaite suggested that it might be better for research to be directed at the economics of endovascular repair for rupture. The cost of devices is high but savings in intensive care use and blood products might offset these.

In conclusion, Braithwaite said, “If one looks at all the studies on EVAR for rupture, at worst the mortality rate is the same as OAR, at best it is much lower. How much more evidence do we need before we adopt the technique?”

The results from two studies conclude that endovascular repair (EVAR) to treat ruptured aortic abdominal aneurysms is a treatment option that should be investigated further. Although there are problems associated with randomization, staffing an emergency-EVAR program and the time associated with arrival and treatment, the ability of EVAR to successfully treat inoperable cases has lead the investigators from both studies to call for large-scale randomized controlled trials to evaluate EVAR as a valid treatment option.

Preliminary results presented at the ESVS annual meeting in Helsinki from the Ruptured EndoVascular Aneurysm Repair (REVAR) trial have, according to lead investigator, Bruce Braithwaite, University Hospital Nottingham, UK, highlighted the need for a large scale, multi-center study to assess the outcomes of patients presenting with ruptured abdominal aortic aneurysms (rAAA) who receive either endovascular aneurysm repair (EVAR) or an open aneurysm repair (OAR).

REVAR is single center, prospective, randomized controlled trial, which compared EVAR with an OAR in patients with a rAAA. Between September 2002 and December 2004, over 100 patients were admitted with suspected rAAA. Patients considered fit for open repair were randomized to EVAR or OAR after consent had been obtained. Some 32 patients were randomized, 14 to EVAR and 18 to OAR. Those in the EVAR group had preoperative spiral computer tomography (CT) angiography to assess suitability.

The primary endpoint of the trial was operative (30-day) mortality, whilst secondary endpoints were moderate or severe operative complications, hospital stay and time between diagnosis and operation. A power calculation required 100 patients to be recruited. A total of four patients died before receiving surgical treatment, one in the EVAR arm, and three in the OAR arm. Following assessment suitability, 12 patients were elected to the EVAR arm and 16 patients to the OAR arm.

The results revealed that 30-day mortality rates was 38.5% (n=12) in the EVAR group and 40% (n=16) in the OAR group. In the intention to treat basis (including per-operative deaths), the results were 43% (n=14) in the EVAR group and 50% (18) in the OAR group.

Moderate or severe operative complications occurred in 77% in the EVAR group and 80% in the OAR group. The median total hospital stay in the EVAR group was 10 days (IQR 6 to 28) and 12 days (IQR 4 to 52) in the OAR group.

Mr Braithwaite reported no significance difference in the median time between diagnosis and operation; 75 (IQR 64 to 126) minutes in the EVAR group and 100 minutes (IQR 48 to 138) in the OAR group.

In addition, Mr Braithwaite noted that no EVAR patients died on the operating table, blood product usage was less in the EVAR group and morbidity was similar (EVAR=77%, OAR=80%).

Following his presentation, Braithwaite said that several valuable lessons had been learnt, most importantly that randomization was possible in an emergency situation and CT scans do not delay treatment. He also commented that only 32% of the patients who presented with rupture were recruited; this will have implications for future trial recruitment numbers. In addition, the mortality rate for EVAR was higher than expected.

At present, the study appears to be seriously under-powered to show a statistically significant difference between the two techniques. If vascular surgeons wish to apply traditional research methods then it may require some 800 patients to be enrolled.

Previously, the New ERA Study, a multicentre study assessing the proportion of patients presenting with a rAAA in whom emergency EVAR is applicable, showed that approximately half the patients presenting with a rAAA were candidates for emergency EVAR.

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