Transcatheter aortic valve implantation in low ejection fraction/low transvalvular gradient patients: the rule of 40.

Background: Several factors have been identified as predictors of events after transcatheter aortic valve implantation (TAVI) but the impact of left ventricular ejection fraction (LVEF) and mean transaortic gradient (MTG) is controversial. This multicenter study aimed to clarify the prognostic role of low LVEF and low MTG after TAVI.

Methods: From 2007 to 2012, 764 consecutive patients with severe symptomatic aortic valve stenosis underwent TAVI at participating hospitals. Patients were divided according to LVEF and MTG into four groups.

Results: Sixty-four patients had LVEF 40% or less and MTG less than 40 mmHg, 76 had LVEF 40% or less and MTG at least 40 mmHg, 163 had LVEF more than 40% and MTG less than 40 mmHg, 461 had LVEF more than 40% and MTG at least 40 mmHg. Two-year mortality was significantly higher in patients with low LVEF and low MTG, whereas it was similar in patients with low LVEF and high MTG, high LVEF and low MTG, and high LVEF and high MTG (51.3 vs. 22.4 vs. 23.3. vs. 25.5%, respectively; P = 0.001). These results were confirmed by multivariate analysis, as the combination of low LVEF and low MTG (both less than 40) was identified as the stronger mid-term mortality predictor (hazard ratio 2.4, confidence interval 95% 1.4-3.9; P = 0.001).

Conclusion: At least one parameter between LVEF or MTG over 40 predicts a good prognosis for TAVI patients at mid-term follow-up, whereas those with both left ventricular dysfunction and low mean aortic pressure gradient are at high risk of all-cause death after TAVI.