Early Impairment of Right Ventricular Functions in Patients with Moderate Asthma and the Role of Isovolumic Acceleration

Abstract

Introduction: Asthma is a common chronic lung disease that affects people all over the world. Pulmonary hyper- tension and right ventricular (RV) dysfunction are possible complications that may develop in the advanced stages of asthma. However, the number of studies investigating asthma and its implications on new RV parameters are very rare. This study aims to evaluate the RV functions in patients with moderate asthma before the development of pulmonary hypertension. Patients and Methods: Forty-one patients with moderate asthma and 40 healthy individuals were enrolled in this case-control study. All participants underwent a detailed two-dimensional echocardiographic examina- tion. RV functions were measured through RV isovolumic acceleration (IVA) index in addition to conven- tional parameters. RV IVA, a tissue doppler derived parameter, was calculated as the ratio between maximum isovolumic myocardial velocity during isovolumic contraction and the time interval from the onset of this wave to the time at its maximum velocity. Results: There were no significant differences between the two groups in terms of baseline clinical character- istics, laboratory findings and echocardiographic parameters measuring left ventricular functions (p> 0.05). In asthmatic patients, RV isovolumic relaxation time and RV myocardial performance index were higher (p= 0.027 and p< 0.001 respectively), while RV fractional area change, tricuspid annular plane systolic excur- sion (TAPSE) and RV IVA values were all lower (p< 0.001). RV IVA was found to be inversely proportional to asthma duration. TAPSE [β= 0.632, 95% CI= (0.121) - (0.225), p< 0.001] and pulmonary artery systolic pressure [β= -0.188, 95% CI= (-0.057) - (-0.003), p= 0.032] were shown as independent predictors of RV IVA. Conclusion: Asthma is an important disease that may result in subclinical RV dysfunction even before the development of pulmonary hypertension. RV IVA, an easily obtained and load-independent parameter, may be a useful and reliable index that sensitively analyzes subtle deteriorations in the contractile function of RV in asthmatic patients. RV IVA may also correlate with asthma duration.