The right ventricular-pulmonary circulation coupling in ischaemic heart disease; a stress echocardiography study

Abstract Objectives This study sought to assess the right ventricular (RV) - pulmonary circulation coupling in patients with coronary artery disease (CAD), preserved echocardiographic indices of right ventricular systolic function and normal pulmonary artery systolic pressure (PASP). Background Patients with CAD are at increased risk for developing left, and ultimately right heart failure. The analysis of underlying mechanisms of worsening RV function has been limited to the hemodynamic sequelae of increased left ventricular (LV) filing pressure leading to pulmonary hypertension. It has been reported that evaluation of RV functional state by using the tricuspid annular plane systolic excursion (TAPSE)/PASP ratio as a surrogate for the RV length-force is of clinical prognostic relevance in patients with known pulmonary hypertension; its role has not been extensively explored in other cardiac conditions including myocardial ischaemia. We hypothesized that the TAPSE/PASP ratio may be able to identify early and subtle changes in RV function in patients with CAD, normal estimated resting PASP, and preserved TAPSE. Methods Data were obtained from a prospectively maintained database, and 223 consecutive patients with preserved right ventricular systolic function (TAPSE≥16mm), and normal resting PASP (≤35mmHg), undergoing stress echocardiography (SE) for suspected coronary artery disease were included. Exclusion criteria: non-ischaemia study, severe valvular disease, poor image quality, resting pulmonary hypertension, reduced right ventricular systolic function. Transthoracic 2-D Doppler echocardiogram was performed by an accredited sonographer at rest and during stress phase and reviewed by two cardiologists unaware of clinical data. Results Fifty-three (24%) SE studies were positive for ischaemia and 170 (76%) negative. Demographic characteristics of both groups are shown in Table 1. All patients had TAPSE≥16mm and a PASP≤35mmHg as per inclusion criteria. The mean TAPSE/PASP ratio was significantly lower in patients with a positive SE suggestive of CAD than controls (0.84±0.22 vs 0.93±0.24, P=0.024). The TAPSE/PASP ratio showed significant correlation with the maximum workload (Watts) achieved (r=0.17, P=0.015) and exercise time (min) (r=0.15, P=0.031), and an inverse correlation with age (r=−0.26, P<0.001) and the development of inducible exertional breathlessness (Exp(B) 0.11, 95% CI 0.028–0.457, P=0.002) on SE. Conclusion Resting TAPSE/PASP was reduced in patients with positive SE, compared to controls. Indexing RV function to RV load, with the use of the TAPSE/PASP ratio identified early changes in RV-pulmonary circulation coupling in CAD patients without resting pulmonary hypertension; this may denote the beginning of subclinical RV dysfunction. Funding Acknowledgement Type of funding sources: None. Table 1