Recovery of left ventricular mechanics following transcatheter aortic valve implantation: long-term follow-up in patients with four subtypes of aortic stenosis
Introduction: Left ventricular mechanics are impaired in patients with severe aortic stenosis (AS). Global longitudinal strain (GLS) may improve after transcatheter aortic valve implantation (TAVI) and may have the potential to identify select patients who have a higher likelihood of survival post TAVI.
Hypothesis: We hypothesized there would be differences in myocardial mechanics measured by GLS and Ejection Fraction (EF) in patients with four subtypes of severe AS, and these differences could predict survival.
Methods: All patients undergoing TAVI pre and short-term post implantation underwent speckle-tracking transthoracic echocardiography from January 2011 - March 2016 using GE Vivid E9 and E95 platforms. Patients were classified according to peak velocity, mean aortic gradient, EF and stroke volume index as: (1) Normal flow and high gradient; (2) Normal flow and gradient with low EF; (3) “Classic” low flow and low gradient; or (4) Paradoxical low flow and low gradient. The study followed them over a 5-year period.
Results: Two hundred-eight patients with severe AS undergoing TAVI were analyzed (table), and 45 patients died during the 5-year study period. Both GLS (-14.02±4 to -14.98± 4.3, p<.0001) and LVEF (56±14% to 58±15%, p=0.0003) improved significantly post TAVI. Across all types of AS, improvement in GLS was associated with a survival benefit, with recovery in alive patients (mean GLS pre-TAVI -14.2 ± 4.1 and post-TAVI -15.2 ± 4.1, p<.001) and no significant recovery in deceased patients (mean GLS pre-TAVI -14.1 ± 4.2 and post-TAVI -14.2 ± 4.4, p=0.8858). Patients with low flow, low gradient AS showed no significant improvement in GLS or LVEF, and had highest mortality rate.
Conclusion: Overall, myocardial mechanics improved significantly post-TAVI. Low flow, low gradient AS patients had the lowest post-procedure GLS and highest mortality. Across all types of AS, patients who survived had GLS recovery, with no significant GLS recovery in patients who died.