How is obstruction relieved in noncardiac surgery patients with aortic stenosis (AS)?

Updated: Jul 16, 2021
  • Author: Lindsay A (Finger) Raleigh, MD; Chief Editor: Sheela Pai Cole, MD  more...
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Answer

Answer

Valve replacement may be performed via surgical or transcather approaches. Transcather aortic valve replacement (TAVR) has emerged as a valuable alternative to surgical AVR (SAVR) in the last decade. Studies have shown that TAVR is superior to medical management in patients ineligible for SAVR [9] and noninferior to SAVR in high-surgical-risk patients. [10, 11] The use of TAVR has also expanded to include intermediate-surgical-risk patients, with studies showing noninferiority to SAVR in this population. [12, 13]

The 5-year follow-up for the PARTNER 2 trial, published in 2020, reported that the incidences of the composite end point of death or disabling stroke at 5 years were similar between surgical and transcatheter aortic valve patients, as were improvements in functioning status and quality-of-life measures. [14] TAVR was associated with higher incidences of paravalvular regurgitation, need for reintervention, and rehospitalization.

In view of these findings, the US Food and Drug Administration (FDA) has approved several ballon-expandable and self-expanding valves for use in intermediate-surgical-risk patients. The results of two large multicenter randomized controlled trials evaluating the role of TAVR (both balloon-expandable and self-expanding valves) in low-surgical-risk patients have been published. [15, 16] These trials both showed an advantage of TAVR over SAVR in the short term.

In the PARTNER 3 trials, the rate of the composite end point of death, stroke, or rehospitalization at 1 year was significantly lower with TAVR than with surgical aortic valve replacement, and TAVR was also associated with a significantly lower rate of new-onset atrial fibrillation (AF) and shorter length of hospitalization. [15]

In the Evolut Low Risk Trial, TAVR was noninferior to surgery with respect to the composite end point of death or disabling stroke at 24 months, and it was associated with a lower incidence of bleeding complications, acute kidney injury, and AF. [16] However, TAVR was associated with a high incidence of moderate-to-severe aortic regurgitation and pacemaker implantation.

The data on long-term outcomes, including structural valve deterioration, in this patient population are still lacking. These trials also excluded patients with BAVs. Studies on this patient population are ongoing. A study by Yoon et al suggested that outcomes may vary according to valve morphology. [17] Randomized controlled trials are lacking at this time.

In 2017, the ACC partnered with several other societies to develop Appropriate Use Criteria for the treatment of patients with severe AS. [18] These guidelines were intended to help further identify and evaluate treatment options, including the appropriateness of TAVR versus SAVR, for a variety of clinical scenarios.

Current guidelines do not recommend AVR in patients with moderate AS unless cardiac surgery is required for other reasons. However, the presence of moderate AS in patients with heart failure who have a reduced ejection fraction remains challenging, as the goal of pharmacologically reducing afterload to improve ejection fraction is hindered by presence of AS. The TAVR UNLOAD trial (NCT02661451), a multicenter randomized controlled trial, is under way to address whether reducing the transaortic gradient with TAVR will improve clinical outcomes in these patients. [19]


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