Clinical Impact of Flow-Adjusted Transprosthetic Pressure Gradient After Aortic Valve Replacement

Background

It is still controversial whether prosthesis-patient mismatch (PPM) adversely affects long-term outcomes after aortic valve replacement (AVR). The aim of this study was to examine whether flow-adjusted pressure gradient is a valid new indicator of long-term outcomes.

Methods

Data collected from 184 patients undergoing isolated AVR for severe aortic stenosis from October 2012 to September 2016 were analyzed. Flow-adjusted pressure gradient was defined as mean pressure gradient divided by stroke volume (MPG/SV). The effect of PPM and MPG/SV on long-term cardiac events and survival was evaluated.

Results

Overall mortality was 8.2%, and the incidence of cardiac events was 9.2% (median follow-up period, 5.5 years). Moderate to severe PPM was present in 30.0% of patients and did not correlate with cardiac events (P = .13). The mean pressure gradient and stroke volume were also not predictive, but MPG/SV was significantly associated with cardiac events (P = 0.016), and the cutoff value of MPG/SV was 0.24 mm Hg/mL. MPG/SV ≥ 0.24 mm Hg/mL was detected as an independent risk factor (adjusted hazard ratio, 5.67; P < .001). The 5-year cardiac event-free rate was lower in patients with MPG/SV ≥ 0.24 mm Hg/mL (72.7% ± 9.6% vs 96.6% ± 1.7%; P < .001). Additionally, the left ventricular mass index at 1 month was significantly lower in patients with MPG/SV ≥ 0.24 mm Hg/mL (P = .028), although there was no significant difference at 6 months (P = .12).

Conclusions

Flow-adjusted pressure gradient has the potential to be a better predictor of long-term outcomes after AVR.