A 70-year-old patient with aortic stenosis and no other notable medical history is undergoing a transcatheter aortic valve replacement (TAVR) procedure. According to a recent study comparing outcomes at three years between TAVR and surgical aortic valve replacement (SAVR) in patients at low surgical risk, which of the following outcomes was MOST likely with TAVR?

  • □ (A) Lower likelihood of a permanent pacemaker
  • □ (B) Lower rate of death or disabling stroke
  • □ (C) Higher mean gradients on the three-year follow-up transthoracic echocardiogram
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Trials of TAVR started in patients deemed to be at prohibitive surgical risk. Over time, patients at lower surgical risk have been enrolled in these trials comparing TAVR with SAVR. Since transcatheter valves are being placed in healthier patients with presumably longer lifespans, study of the longevity and outcomes associated with the valves is even more important.

The Evolut Low Risk trial, a multinational, prospective, randomized study, evaluated low-risk patients with aortic stenosis undergoing either TAVR or SAVR. The three-year outcomes for this trial were recently published, which included the primary end point of all-cause mortality or disabling stroke at three years. The study was conducted at 86 sites in seven countries from March 2016 to May 2019 and included 730 TAVR patients and 684 SAVR patients. Overall, patients who received a TAVR had a lower rate of death or disabling stroke compared with SAVR at three years (7.4% TAVR vs. 10.4% SAVR; hazard ratio, 0.70; 95% CI, 0.49-1.00). In addition to this benefit, the transcatheter valves performed well compared with the surgical valves. The mean gradients on the three-year follow-up transthoracic echocardiogram were lower for TAVR and had higher effective orifice areas compared with SAVR. The authors attributed this finding to the supra-annular position of the valve. No differences were found in valve reoperations between TAVR and SAVR, with comparable thrombosis and infection rates, although this metric needs to be tracked for a longer period.

The disadvantages of TAVR continue to be the increased risk for permanent pacemaker and paravalvular leak. Patients undergoing TAVR were 2.8 times more likely to need a pacemaker than those undergoing SAVR (23.2% TAVR vs. 9.1% SAVR; 95% CI, 2.08-3.79). However, as the technology evolves, there are structural changes being made to the valves that may decrease the risk of heart block and paravalvular leak. Additionally, as seen in the primary composite outcome, the presence of a paravalvular leak or pacemaker does not seem to increase the risk of stroke or death.

Overall, this study demonstrated that the TAVR procedure had a lower risk of death or disabling stroke in low-risk patients at three years compared with SAVR. This population will continue to be followed by the study authors through the 10-year mark to provide longer-term data on the performance of these valves.

Answer: B