Aim: The aim of this study was to investigate left ventricular diastolic function in a group of homozygous Black African patients with sickle-cell disease via echocardiography-Doppler, and to describe the possible hemodynamic implications of these findings.
Patients and methods: Fifty patients with sickle-cell anemia from two hematology departments in Yaoundé volunteered to participate in the study, carried out between May-October 1995. The presence of any other associated pathology (cardiovascular disorder, acute drepanocytic anemia, pregnancy) was excluded following a clinical, hematological and echocardiographic examination. A sex- and age-matched control group consisting of 50 healthy subjects was selected after the same examination criteria had been met. Mitral flow recorded by pulsed Doppler was measured, and the amplitudes of the E and A waves of the proto- and telediastolic flow, the E/A ratio, the decrease over time (DT) for the E wave, and the left ventricular isovolumetric relaxation time were also calculated. The limits of the confidence interval for the mean DT of the control group were used as the criterion to determine the following in the patient population: i) relaxation disorder profile, with DT > 154 ms; ii) restrictive disorder profile, with DT < 137 ms.
Results: The dimensions of the cardiac cavities and the left ventricular mass were higher in the patient population; 34 cases of left auricular dilatation (68%) and 33 cases of left ventricular dilatation 8 66%) were observed. In only two patients was a systolic dysfunction noted. The amplitudes of the mitral flow E and A waves were increased, and the DT was longer in the sickle-cell group. Forty patients (80%) had abnormal diastolic function, with a marked predominance of the 'relaxation disorder' profile (60%). The restrictive disorder profile was only observed in ten sickle-cell patients (20%), while ten others displayed a normal profile (20%). The means of the various clinical and echocardiographic parameters of the three categories of sickle-cell patients (based on their diastolic profile, i.e., normal, relaxation disorder, restrictive disorder) were compared. The clinical parameters could be superimposed in the 3 categories. The dimensions of the left auricle and the telesystolic diameter of the left ventricle were significantly larger in the restrictive disorder category. The latter category appeared to be more symptomatic, and included the two isolated cases of systolic dysfunction.
Conclusion: Left ventricular diastolic dysfunction is commonly encountered in sickle-cell cases in the Cameroon. The restrictive disorder profile is less frequently observed, but appears to be more harmful at the hemodynamic level. The present results suggest that the study of diastolic function in patients with sickle-cell anemia could help identify hemodynamically at-risk subjects who require more specific cardiovascular care, even before a noticeable alteration in systolic function has taken place.