Resting right ventricular to pulmonary artery uncoupling in chronic coronary syndromes: functional significance and prognostic impact

Background Resting and exercise right ventricular to pulmonary artery coupling (RV/PA) is an important prognostic determinant in several left heart and right heart diseases Aim To investigate the prognostic impact of RV-PA coupling at rest in patients with chronic coronary syndromes (CCS). Methods From July 2016 to April 2025, we enrolled 3904 all-comers (age 63±13 years, 2396 [61%] males, left ventricular ejection fraction = 60±11%) with CCS referred from 39 certified laboratories in 16 countries. Key left and right transthoracic echocardiography (TTE) measurements were obtained at baseline and during exercise according to the current recommendations of the American Society of Echocardiography and the European Association of Cardiovascular Imaging. Tricuspid annular plane systolic excursion (TAPSE) was measured from 2D-targeted M-mode tracing. Pulmonary artery systolic pressure (sPAP) was non-invasively estimated from the tricuspid regurgitant velocity (TRV) jet according to the following formula: sPAP=4 x peak TRV2 + right atrial pressure (RAP). Inferior vena cava (IVC) size and collapsibility were used for estimating RAP. TAPSE/sPAP ratio (mm/mmHg), as an index of RV function and PA coupling, was considered abnormal when <0.7 mm/mmHg. All patients underwent clinically indicated ABCDE-SE, with ACE steps in all patients, step D in 2009, step B in 3442, and all 5 steps in 2001 pts. The employed stress modality was exercise (n=2820) or pharmacological stress (n=1084; with vasodilator, n=622; or dobutamine, n=462). Follow-up was completed in 1022 patients with a composite endpoint of major adverse cardiac events (MACEs). Results RV-PA uncoupling at rest was present in 174 (Group 1) and absent in 3703 patients (Group 2). Group 1 showed greater functional impairment at rest and during stress (table). During a median follow-up of 449 days (interquartile range: 250-708), 56 deaths, 54 acute myocardial infarctions, and 43 acute heart failures in 270 patients occurred. The cumulative incidence rate of MACE was 19% in RV-PA uncoupling group 1 vs 7.2% in group 2 (P value < 0.001). Conclusion In patients with CCS, resting signs of RV-PA uncoupling are associated with multiple functional vulnerabilities at rest and during stress, with more severe pulmonary congestion, global left ventricular dysfunction, coronary microvascular dysfunction, blunted cardiac sympathetic reserve and higher incidence of MACE rate.Table 1:Clinical and echocardiographic