Page 129 - Advanced echocardiography in characterization and management of patients with secondary mitral regurgitation

and dysfunction, distortion of the mitral valve apparatus and increasing MR volume which can lead to pulmonary congestion, increased pulmonary pressures and RV dilation and dysfunction (1, 2). PH is observed in approximately 40% of patients with secondary MR (24) and is associated with adverse outcomes, even after correcting MR with surgical or transcatheter edge-to-edge mitral valve repair (7, 25). In addition, RV dysfunction has been associated with an increased risk of mortality in patients with HF (5) and is a major predictor of outcome specifically in patients with secondary MR (6, 26). However, RV systolic function is highly dependent on pulmonary pressures and different afterload conditions can significantly influence its estimation (2). Integration of PH (assessed by PASP) and RV function (assessed by TAPSE) using the TAPSE/PASP ratio enables an estimation of RV-PA coupling. Until recently, measures for RV-PA coupling were evaluated invasively. A study by Tello et al. (12) validated TAPSE/PASP ratio as a surrogate of RV-PA coupling in 52 patients with PH. A TAPSE/PASP <0.31 mm/mmHg defined RV-PA uncoupling and was associated with poor outcome. Guazzi et al. (9) investigated the TAPSE/PASP ratio in 293 HF patients with both preserved and reduced LVEF. A TAPSE/PASP ratio <0.36 mm/mmHg was the best cutoff value associated with prognosis (area under the curve 0.78; 95% CI 0.75-0.86; P<0.001). The TAPSE/PASP cutoff values most strongly associated with mortality in these prior studies were similar to that observed in the current large-scale study of patients with secondary MR. In the present population, a TAPSE/PASP <0.35 mm/mmHg was independently associated with long-term mortality. In contrast, TAPSE alone was not an independent predictor of long-term outcomes.
Clinical implications of TAPSE/PASP in secondary MR
The use of transcatheter mitral valve repair in HF patients with secondary MR is increasing. Two major trials that evaluated the prognostic impact of transcatheter edge-to-edge mitral valve repair in HF patients with secondary MR reported varying results in terms of mortality and symptomatic improvement (3, 4). Although patients were selected for these trials according to contemporary guidelines (18, 27), their conflicting results highlight the challenge of identifying patients who may benefit from intervention. In this regard baseline RV dysfunction has been shown to be an important predictor of outcomes after mitral valve intervention (28, 29). Osterech et al. (30) demonstrated higher all-cause mortality in patients with compared without baseline RV dysfunction (assessed by TAPSE) in 130 patients with secondary MR undergoing transcatheter mitral valve repair. However, RV dysfunction is significantly affected by afterload and the sole use of TAPSE may provide an imprecise estimation of RV contractility. As demonstrated in the present study, by taking into account loading conditions the TAPSE/PASP ratio (reflecting RV-PA coupling) may further improve
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