IMPROVE: Endovascular, Open Repair for Ruptured Aneurysm Yielded Similar 1-Year Survival

Rami O. Tadros, MD, RPVI

There are three clear points in this paper. No. 1, the mortality rate in women with ruptured aneurysms being treated with EVAR is better than in women being treated with open repair. No. 2, the patients randomized to the EVAR arm had shorter lengths of stay in the hospital, 17 days vs. 26 days. No. 3, those randomized to the EVAR cohort had better quality of life after the procedure compared with those randomized to the open-repair group.

The study found that the mortality rates were comparable between patients randomized to the EVAR group and patients randomized to the open-repair group, but that’s just a surface finding. It was an intention-to-treat analysis, which meant that the approximately 40% of patients assigned to the endovascular group who ended up needing open repair were still counted as part of the EVAR group. Because of that, it’s a bit difficult to conclude that these treatments have comparable outcomes.

Additionally, the inclusion criteria for EVAR were consistent with most instructions for use for the devices, but the study doesn’t really take into consideration that a large percentage of patients in the general population are being treated outside of traditional instructions for use. The limits of devices are being pushed. There is a good chance, depending on the operator, that a larger percentage of patients could have undergone EVAR if the traditional instructions for use were violated, and they could potentially have had better mortality.

I would like to see further research done using more liberal anatomic criteria when treating ruptured aneurysms, to see if that produces a bigger disparity in mortality outcomes. If the physicians are allowed to push the limits of the devices, would they end up with better mortality results? In my own research, I’ve studied how anatomic criteria impacts outcomes. In our institution, we get a lot of complicated aneurysm referrals, and only about 30% of all comers are treated completely within instructions-for-use criteria. Almost 70% are being treated outside the instructions for use, but despite that, we’ve demonstrated that the aneurysm-related mortality outcomes are comparable between those within and outside the criteria when looked at over time. In the right hands, just because you’re violating these criteria doesn’t mean you’re going to end up with a worse outcome. A trial where a physician could push the limits of the devices would be more meaningful.

Another area that could use further research is type of device: bifurcated stent grafts vs. aorto-uni-iliac stent grafts. The latter can be deployed more rapidly but require a femoral-to-femoral bypass and occlusion of the contralateral iliac limb. It would be important to see whether one type of device was preferable for treatment of ruptured aneurysms. If you can exclude the aneurysm faster, does that lead to improved outcomes? Unfortunately, that study has not been done.

I would not want people to take away from this that if someone comes in with a ruptured aneurysm, it doesn’t make a difference whether they undergo EVAR or open repair. If a person is a candidate for EVAR, they should have EVAR. It should be the first-line treatment given what some of the observational studies have shown: approximately 25% mortality for EVAR vs. approximately 50% for open repair. If EVAR cannot be performed given anatomic restrictions or whatever the issue may be, then of course the alternative is open aneurysm repair.