Improving Patient Selection for EVAR Versus Open Repair

Vascular Disease Management spoke with Daniel Clair, MD, Chairman of the Department of Surgery for the Palmetto Health-USC Medical Group in Columbia, South Carolina. Dr Clair discussed the impact of new technologies for aortic aneurysm therapy on the field and which patients are best suited for open abdominal aortic aneurysm repair. He presented on these topics at the 2020 International Symposium on Endovascular Therapy (ISET) in Hollywood, Florida.

Which patients are best suited for endovascular aneurysm repair (EVAR) versus open aortic repair?

Colleagues often discuss the proposed the proposed UK National Institute for Health and Care Excellence (NICE) guidelines that recommend that, for the most part, EVAR not be offered to patients. According to the proposed guidelines, patients who are fit and can undergo surgery should have open surgery, and patients who are not fit enough to undergo surgery should be managed medically. 

The way that the technology for EVAR has been applied is part of what has led to this situation. About 40% to 50% of patients are receiving endografts outside of instructions for use (IFU) for those devices, and most studies show somewhere between .5% and 1% risk of rupture in real-world patients who are treated with endografts.¹ That rate of rupture risk is problematic because we perform aneurysm repair to reduce the risk of rupture. In fact, in the Medicare database, the risk of rupture over an 8-year period is about 5.5%.² Even more concerning, many of the aneurysms being treated are small. Overall, we are fixing patients with poor anatomy early, and outcomes are poor.

How can the problem of poor real-world outcomes for endografts be addressed? 

We should consider how we can optimize outcomes in patients in whom endografts do not fit within the IFU standards. Some patients may need fenestrated endografts, while other patients may require open surgery. For example, a 65-year-old patient without significant comorbidities has an average life expectancy of almost 20 years. If that person has an aneurysm and an endograft is placed, the endograft must be successful for 20 years. However, if patients are followed for 20 years, an enormous number will require reintervention, re-lining, or revision of the endograft, which comes with a physiological and financial cost.

We need to talk to healthy patients about having open surgery versus endografting, and we should ensure that patients understand the risks of needing re-intervention and potentially even an explant if they undergo endografting. EVAR should be performed in patients with favorable anatomy, and healthy patients should not be candidates for EVAR unless they have had an extended discussion of the risk of an endograft versus open repair, because open repair has a very low risk of complication in a healthy individual. EVAR and open repair both have appropriate times for use. We need to identify which patients are best treated with endografting, and which patients are best treated with open surgery. I am a proponent of endografting in the right circumstances, and I think EVAR works very well.

Have any other factors led to the current issues with patient selection for EVAR versus open surgery?

Open surgery takes more time to perform, incurs more risk of litigation for the physician, and requires more recovery time for the patient in the hospital. EVAR allows a patient to recover more quickly in the short term, but there is a significant risk of reintervention in the longer term. We need to better educate patients about the reality of endografts. A significant percentage of patients will have an aneurysm expansion, and some patients will require a re-intervention of some kind within a few years. The re-intervention might be very complicated, and some patients may need multiple re-interventions. Additionally, patients with endografts will need to undergo continued imaging surveillance and endure the accompanying radiation exposure and anxiety provoked by the experience. On the other hand, open surgery may necessitate a secondary intervention in the long term, but these reinterventions typically occur much later than with endografting.

Which patients are ideal candidates for endografts, and when should aneurysms be repaired?

Older individuals with good anatomy should have endografts. Additionally, rather than fixing an aneurysm with complex anatomy at 5.5 cm, we may want to fix that aneurysm at 6.5 cm. If we do repair the aneurysm at 5.5 cm, we need to consider whether a fenestrated endograft is the best option. 

Tell us about new technologies for aortic aneurysm.

The Heli-FX EndoAnchor (Medtronic) is basically a corkscrew that is placed at the top of the graft to hold the graft in place. There is some evidence that routinely using this device may increase the number of patients who experience sac shrinkage. My guess is that we may be missing a subtle proximal pressurization of the aneurysm sac that can be resolved with a device that fixes the endograft to the aortic wall in the same manner as in surgical repairs. We need to find a way to resolve the expanding aneurysm and the need for intervention, particularly intervention due to proximal neck problem.

Are there any other technologies that you want to mention?

Eliminating more interventions and decreasing mortality is our goal. Interventions are costly for the individual patient and for society as a whole. An expanding aneurysm means that a patient has a much higher risk of mortality versus an aneurysm that shrinks or does not increase in size. There are exciting developments in this area in polymer technology. There is some evidence that using polymers and reducing the risk of type I and type II endoleaks reduces overall mortality and may reduce the need for secondary intervention over the long term, if we can obtain adequate proximal fixation. 

What changes to the field do you anticipate in the next five years?

I think we will see the pendulum swing back with aneurysm repair, and we will perform more open repairs than at the current time. That trend will likely continue until we have some change in the technology available.   

REFERENCES

1. Chang RW, Goodney P, Tucker LY, et al. Ten-year results of endovascular abdominal aortic aneurysm repair from a large multicenter registry. J Vasc Surg. 2013;58(2):324-332. 

2. Schermerhorn ML, Buck DB, O'Malley AJ, et al. Long-term outcomes of abdominal aortic aneurysm in the medicare population. N Engl J Med. 2015;373(4):328-338.