22 October 2020
Background: Pulmonary artery (PA) pulsatility index (PAPi), calculated as (PA systolic pressure – PA diastolic pressure)/right atrial pressure, emerged as a novel predictor of right ventricular failure in patients with acute inferior myocardial infarction, advanced heart failure, and severe pulmonary hypertension. However, the prognostic utility of PAPi in transcatheter mitral valve repair (TMVR) using the MitraClip® system has never been tested. Objective: To assess the prognostic impact of PAPi in patients with severe functional mitral regurgitation (MR) and chronic heart failure (CHF) undergoing TMVR. Methods: Consecutive patients with severe functional MR (grade 3+ or 4+) and CHF who underwent successful TMVR (MR ≤2+ at discharge) were enrolled and divided into 3 groups according to PAPi (A: low PAPi ≤2.2; B: intermediate PAPi 2.21–3.99; C: high PAPi ≥4.0). The primary endpoint was a composite of all-cause mortality and rehospitalization due to CHF during a mean follow-up period of 16 ± 4 months. The impact of PAPi on prognosis was assessed by a receiver-operating characteristic (ROC) analysis and a multivariable Cox proportional hazard regression analysis investigating independent predictors for outcome. Results: 78 patients (A: n = 27, B: n = 28, C: n = 23) at high operative risk (logistic EuroSCORE [European System for Cardiac Operative Risk Evaluation] 18.8 vs. 21.5 vs. 20.6%; nonsignificant) were enrolled. Mean PAPi was 1.6 ± 0.41 vs. 2.9 ± 0.53 vs. 6.8 ± 3.5; p < 0.001). Patients with low PAPi showed significantly higher rates of early rehospitalization for heart failure at the 30-day follow-up (14.9 vs. 7.1 vs. 4.3%; p = 0.04). In the long term, a significantly lower event-free survival for the combined primary endpoint was observed in the low PAPi group (44.4 vs. 25.0 vs. 20.3%; log-rank p = 0.016). ROC curve analysis revealed that optimal sensitivity and specificity were achieved using a PAPi cutoff of 2.46 (sensitivity 83%, specificity 78.3%, area under the curve 0.82 [0.64–0.99]; p = 0.01). In Cox regression analysis, PAPi ≤2.46 was an independent predictor for the combined primary endpoint (hazard ratio 2.85; 95% confidence interval 1.15–7.04; p = 0.023). Conclusions: PAPi is strongly associated with clinical outcome among patients with CHF and functional MR undergoing TMVR. A PAPi value ≤2.46 predicts a worse prognosis independent of other important clinical, echocardiographic, and hemodynamic factors. Therefore, PAPi may serve as a new parameter to improve patient selection for TMVR.