The Bumpy Road to Less Invasive Cardiac Interventions for Severe Aortic Stenosis

Abstract

Aortic stenosis (AS) is a disease of aging, characterized by progressive calcification and fibrosis of the aortic valve and, ultimately, cardiac failure. The onset of symptoms is an indicator of high near-term mortality. The gold standard to treat AS is surgical aortic valve replacement (SAVR), an invasive and risky intervention for many patients who are elderly and have multiple comorbidities. Due to its invasiveness, 30%-40% of patients with symptomatic AS are too sick for SAVR. For those who can tolerate SAVR, however, long-term outcomes are very good. Over the last decade, a push toward less invasive approaches to treat AS has arisen to address a considerable unmet clinical need. Since 2002, a catheter-based approach to aortic valve replacement (TAVR) has led the drive toward less invasive approaches; however, that approach carries a risk of stroke among other complications, and it has uncertain long-term durability. Because of these issues, many cardiologists and cardiac surgeons are reluctant to offer TAVR to those who are healthy enough to undergo SAVR. Herein, we describe a third option for AS patients, one that has potential to enable a safe and effective treatment for a large number of high-risk patients with AS. Known as Aortic Valve Bypass (AVB) (or apicoaortic conduit), this procedure leaves the diseased native valve in place, while creating an alternative left ventricular outflow tract to relieve blood flow obstruction from the stenosed valve. Almost 100 years of physiologic rationale supports the use of AVB. It is durable and halts natural AS. Historic AVB never became popular among surgeons because of its procedural complexity. However, in recent years, a new device (known as the Correx Applicator) that automates the most challenging process of the AVB procedure (i.e., apical coring) is now creating a resurgence of interest in the AVB technique. It allows AVB to be performed on a beating heart and in a less invasive manner than SAVR. Stroke risk and other complications common to both SAVR and TAVR are minimized. In the presence of a markedly simplified AVB procedure, patients with AS now have more treatment options than ever. The comparative effectiveness data for SAVR, TAVR, and Correx AVB may drive new treatment standards in the years ahead.