Incremental value of right heart metrics and exercise performance to well-validated risk scores in dilated cardiomyopathy.

Aims: Risk stratification in heart failure (HF) relies on several established clinical risk scores, however, myocardial deformation, right heart metrics, and exercise performance have not usually been considered. This study sought to assess the incremental value of advanced echocardiographic and cardiopulmonary exercise testing (CPX) parameters to validated risk scores in HF. Methods and results: The Meta-Analysis Global Group in Chronic Heart Failure (MAGGIC) and Metabolic Exercise Test Data Combined with Cardiac and Kidney Indexes (MECKI) scores were applied to 208 ambulatory patients with dilated cardiomyopathy (DCM) who completed echocardiography in conjunction with CPX as part of the Stanford Exercise Testing registry. Patients were followed for the composite end point of death, heart transplant, left ventricular device implantation, and hospitalization for acute HF. Mean age, left ventricular ejection fraction (LVEF), and left ventricular global longitudinal strain (LVGLS) were 47 ± 13 years, 33 ± 13%, and -10.6 ± 4.4%, respectively, while right ventricular free-wall longitudinal strain was -18.8 ± 5.5%. Partial correlation mapping identified strong correlations between LVEF, LVGLS, and LV systolic strain rate, with a moderate correlation between these metrics and peak VO2. Over a median follow up of 5.3 years, the composite end point occurred in 60 patients. Cox proportional hazards identified MAGGIC score [hazard ratio (HR) (2.04 [1.39-3.01], P < 0.01], peak VO2 HR (0.52 [0.28-0.97], P = 0.04), and right atrial volume indexed (RAVI) HR (1.31 [1.07-1.61], P < 0.01) as independent correlates of outcome. RAVI remained an independent correlate when combined with the MECKI score (2.21 [1.59-3.07]), P < 0.01, RAVI, 1.33 [1.06-1.67], P = 0.01).
Conclusion: Our study demonstrates that RAVI is complementary to well-validated HF risk scores and highlights the importance of exercise performance in DCM.