New possibilities in determining efficacyof drug therapy and prognosis for cardiovascular complications in chronic heart failure
Background. Despite improvements in traditional pharmacotherapy and methods of instrumental diagnostics, CHF remains an important issue of medicine and society. In clinical practice, insufficient attention has been paid to the functional status of the body, the reserve of its regulatory and adaptive reactions designed for maintaining the homeostasis. A method of quantifying the regulatory-adaptive status (RAS) would be appropriate for determination of drug efficacy and prediction of cardiovascular complications in CHF. Aim. To establish significance of quantifying the RAS in determination of drug efficacy and risk of cardiovascular complications in CHF. Materials and methods. 100 patients with essential hypertension and/or IHD associated with FC III CHF and impaired left ventricular systolic function participated in the study. Patients receiving a multimodality treatment (quinapril, torasemide, spironolactone) were randomized to two groups. The first group consisted of 56 patients (aged 57.5±21.7) receiving metoprolol succinate 59.1±12.1 mg / day; the second group included 44 patients (aged 57.1±21.4) receiving ivabradine 12.1±4.6 mg / day. Cardio-respiratory synchronism test (for quantitative evaluation of RAS), EchoCG, treadmill metrics, plasma level of N-terminal pro-brain natriuretic hormone, and 6-min walk test were performed at baseline and in 6 months. Cardiovascular complications were analyzed for the next 2 months of the monitored drug therapy. Results. Either regimen of multimodality therapy with metoprolol succinate or ivabradine equally improved the structure and function status of the myocardium, increased exercise tolerance, and reduced neurohumoral hyperactivation. In this process, the benefit of ivabradine regimen for the RAS was greater. Clinical efficacy of the pharmacotherapy was comparable in both groups; incidences of hospitalization for decompensated CHF, ischemic stroke, MI, and cardiovascular fatality did not differ. When the baseline RAS was low and unsatisfactory, the incidence of cardiovascular complications was higher. The originally unsatisfactory RAS was associated with increased risk of sudden cardiac death. Conclusion. The RAS, as an unbiased index for severity of structure and function disorders and intensity of neurohumoral hyperactivation and autonomic dysfunction, can be used for determination of drug efficacy and prediction of cardiovascular complications in patients with CHF.