Progressive right ventricular dysfunction and exercise impairment in patients with heart failure and diabetes mellitus: insights from the T.O.S.CA. Registry

Background: Findings from the T.O.S.CA. Registry recently reported that patients with concomitant chronic heart failure (CHF) and impairment of insulin axis (either insulin resistance-IR or diabetes mellitus-T2D) display increased morbidity and mortality. However, little information is available on the relative impact of IR and T2D on cardiac structure and function, cardiopulmonary performance, and their longitudinal changes in CHF. Methods: Patients enrolled in the T.O.S.CA. Registry performed echocardiography and cardiopulmonary exercise test at baseline and at a patient-average follow-up of 36 months. Patients were divided into three groups based on the degree of insulin impairment: euglycemic without IR (EU), euglycemic with IR (IR), and T2D. Results: Compared with EU and IR, T2D was associated with increased filling pressures (E/e'ratio: 15.9 ± 8.9, 12.0 ± 6.5, and 14.5 ± 8.1 respectively, p < 0.01) and worse right ventricular(RV)-arterial uncoupling (RVAUC) (TAPSE/PASP ratio 0.52 ± 0.2, 0.6 ± 0.3, and 0.6 ± 0.3 in T2D, EU and IR, respectively, p < 0.05). Likewise, impairment in peak oxygen consumption (peak VO2) in TD2 vs EU and IR patients was recorded (respectively, 15.8 ± 3.8 ml/Kg/min, 18.4 ± 4.3 ml/Kg/min and 16.5 ± 4.3 ml/Kg/min, p < 0.003). Longitudinal data demonstrated higher deterioration of RVAUC, RV dimension, and peak VO2 in the T2D group (+ 13% increase in RV dimension, - 21% decline in TAPSE/PAPS ratio and - 20% decrease in peak VO2). Conclusion: The higher risk of death and CV hospitalizations exhibited by HF-T2D patients in the T.O.S.CA. Registry is associated with progressive RV ventricular dysfunction and exercise impairment when compared to euglycemic CHF patients, supporting the pivotal importance of hyperglycaemia and right chambers in HF prognosis. Trial registration ClinicalTrials.gov identifier: NCT023358017.