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Long-Term Results of Low-Risk TAVR Studies

Core Concepts
TAVR trials show divergent long-term results.
The latest results from the PARTNER-3 and Evolut trials comparing transcatheter aortic-valve replacement (TAVR) to surgery in low-risk patients reveal differing long-term outcomes. PARTNER-3 Trial No significant difference in primary composite outcomes at 5 years between TAVR and surgery groups. Similar rates of death, stroke, and rehospitalization in both groups. Aortic-valve durability and hemodynamic performance comparable between TAVR and surgery. Secondary endpoints like atrial fibrillation and bleeding less frequent in TAVR group. Evolut Low-Risk Trial TAVR group shows a 26% relative reduction in all-cause mortality or disabling stroke compared to surgery at 4 years. Lower rates of primary endpoint components with TAVR. Higher rates of pacemaker implantation in the TAVR group. Superior valve performance and hemodynamics with the Evolut valve compared to surgery. Comparison and Analysis PARTNER-3 outcomes plateaued at 5 years, while Evolut trial showed increasing benefits with TAVR over time. Possible factors influencing outcomes include COVID pandemic effects and differences in patient characteristics. Mortality rates in surgery groups varied between trials, impacting overall results. Competition between TAVR valves highlighted, with Evolut valve showing superior performance. Future Implications Longer-term follow-up crucial as surgical valves may fail between 5-10 years. Transition from surgery to TAVR likely to accelerate in low-risk patients. TAVR emerging as the default therapy due to logistical and patient benefits.
"The incidence of the composite end point of death, stroke, or rehospitalization related to the valve, the procedure, or heart failure was similar in the TAVR group and the surgery group, occurring in 22.8% of patients in the TAVR group and 27.2% in the surgery group, which is a nonsignificant difference (P = .07)." "By 4 years, the primary endpoint of all-cause mortality or disabling stroke had occurred in 10.7% of the TAVR group and 14.1% in the surgery group (hazard ratio [HR], 0.74; P = .05), representing a 26% relative reduction with TAVR." "New permanent pacemaker implantation was significantly higher in the TAVR group (24.6% vs 9.9%)." "At 4 years, 84.7% of TAVR patients and 98.4% of surgery patients had no or trace paravalvular regurgitation, and there was no difference between groups in moderate or greater paravalvular regurgitation (0.4% TAVR vs 0.0% surgery)."
"Both trials have clearly reaffirmed clinical and echocardiographic benefits of TAVR as a meaningful alternative therapy to surgery in low-risk severe symptomatic aortic stenosis patients." - Marty Leon, MD "It has less structural valve deterioration, less severe patient prosthetic mismatch, and superior hemodynamics compared to surgery. All these factors are translating into a widening difference in clinical event curves year on year with the Evolut valve vs surgery." - Michael Reardon, MD

Key Insights Distilled From

by Sue Hughes at 10-26-2023
Low-Risk TAVR Studies: Divergent Long-Term Results

Deeper Inquiries

Why did the outcomes of the PARTNER-3 and Evolut trials differ over time?

The outcomes of the PARTNER-3 and Evolut trials differed over time due to several factors. In the PARTNER-3 trial, the initial benefits of TAVR over surgery seemed to have attenuated over the longer-term, with main outcomes looking very similar in both groups after 5 years. On the other hand, in the Evolut trial, the early benefit in all-cause mortality or disabling stroke seen in the TAVR group continued to increase, with a 26% relative reduction in this endpoint with TAVR vs surgery at 4 years. One possible explanation for these differences is the intrinsic risk level of the patients enrolled in each trial. The Evolut trial enrolled patients at the upper end of the low-risk population, while the PARTNER-3 trial enrolled patients at the lower end. This difference in patient risk profiles may have influenced the outcomes observed in each trial.

Is the COVID pandemic a significant factor influencing the results of TAVR vs surgery in low-risk patients?

The COVID pandemic may have been a significant factor influencing the results of TAVR vs surgery in low-risk patients, particularly in the PARTNER-3 trial. During the 2-year COVID period, a higher percentage of deaths and strokes occurred in the TAVR patients compared to the surgery patients. One possible explanation for this observation is that surgery patients were receiving more anticoagulation due to a higher prevalence of paroxysmal atrial fibrillation, which may have provided some cardioprotective effects. Additionally, COVID is known to be a stimulus for thrombogenic events, and the increased anticoagulation in the surgery group may have contributed to better outcomes in that group during the pandemic. These factors suggest that the COVID pandemic may have influenced the results of TAVR vs surgery in low-risk patients.

How might the increasing use of TAVR in younger patients impact future treatment guidelines and practices?

The increasing use of TAVR in younger patients is likely to have a significant impact on future treatment guidelines and practices. Despite current guidelines recommending surgery for patients under 65 years, there has been a notable rise in the use of TAVR in younger patients needing isolated aortic valve replacement. This shift in practice is driven by patient preference for TAVR and the demonstrated benefits of the procedure, even in younger populations. As more data supports the efficacy and safety of TAVR in younger patients, treatment guidelines may evolve to reflect this trend. Future trials randomizing between TAVR and surgery in younger patients may become less feasible as patient demand for TAVR grows. Ultimately, the increasing use of TAVR in younger patients is likely to lead to a continued momentum towards TAVR being the default therapy for aortic valve replacement, potentially reshaping treatment guidelines and practices in the field.