Background: Recent data suggests that right ventricular to pulmonary artery (RV-PA) uncoupling negatively influences prognosis in several clinical conditions. Little is known about the role of RV-PA coupling in patients with mitral regurgitation (MR).
Objectives: Our study aimed to investigate the role of RV-PA coupling in a cohort of patients with chronic severe primary MR (PMR) undergoing cardiac surgery.
Methods: We retrospectively assessed patients with severe PMR undergoing surgical repair or replacement from January 2018 to December 2021. Patients underwent preoperative transthoracic echocardiography and speckle tracking analysis. RV-PA coupling was assessed by the ratio of RV global longitudinal strain (RVGLS) and pulmonary artery systolic pressure (PASP). Patients were divided into tertiles according to RVGLS/PASP values. We studied the association between RV-PA coupling and the length of stay in the intensive care unit (ICU), the length of hospitalization and NYHA class at discharge.
Results: A total of 120 patients (mean age 65.2 ± 11.9 y) were included in the study. 84 (70%) patients underwent surgical valve repair while 36 (30%) underwent surgical valve replacement. Patients with lower RVGLS/PASP values had lower left ventricular ejection fraction (LVEF: 58.1±10.5% vs 62.0±7.4% vs 62.9±5.3%, p=0.018), more dilated left atrial volume (LAV: 71.0±21.9ml/m2 vs 62.3±21.2ml/m2 vs 55.9±23.9ml/m2, p=0.012) and lower peak atrial longitudinal strain values (PALS: 21.1 ± 10.1% vs 29.7 ± 11.0% vs 34.1 ± 9.4%, 0.001). Patients with lower RVGLS/PASP ratio had longer hospital stay (11.5 ± 3.9 vs 10.4 ± 3.4 vs 8.5 ± 2.2 days, 0.001) and stay in ICU (3.7 ± 2.0 vs 2.8 ± 2.4 vs 1.9 ± 1.3 days, 0.001). There was a significant inverse association between RVGLS/PASP and hospital stay and length of stay in ICU [for each 0.1%/mmHg increase: respectively β=-0.59 (-0.89; -0.29), 0.001 (Figure 1) and β=-0.35 (-0.53;-0.17), 0.001 (Figure 2)]. Moreover, RVGLS/PASP was also associated with the probability of having a NYHA class ≥ 2 at discharge [OR 0.69(0.54; 0.89), p= 0.004 (Figure 3)]. These relationships were confirmed after adjustment for other variables.
Conclusions: Our study suggests that in patients with PMR undergoing cardiac surgery RV-PA coupling may identify a more compromised group of patients and that it is related to clinical outcomes in the very short-term after surgery.