Predictors of early mortality following cardiac surgery for rheumatic heart disease at a national referral hospital in Dar es Salaam, Tanzania: A retrospective study

Abstract

[Accepted Research Article]

Background: Rheumatic heart disease (RHD) is endemic in Tanzania. It is ranked third among the most common causes of heart failure after hypertensive heart diseases and cardiomyopathies. This study aimed to determine the predictors of early operative mortality for RHD at Muhimbili National Hospital, Tanzania.

Methods: This retrospective cross-sectional study of 212 patients operated due to RHD from May 2008 to December 2012. Patients’ demographic and clinical data at admission and within 30 days of the index elective cardiac surgery were recorded in a predefined clinical record form. Data were entered and analysed using Statistical Package for Social Sciences version 24 and STATA version 13. The Chi-square and Fisher’s exact tests were utilized to compare categorical variables. Variables with a p-value <0.2 at bivariable analysis were included in a multivariable modified Poisson regression model.

Results: Out of 212 patients, 140 (66%) were females. The median age was 21 years (interquartile range 15 – 32 years). One hundred and forty-five (68.4%) patients underwent valve replacement, out of which 113 (77.9%) were single (mitral), 17 (11.7%) aortic, and 15 (10.4%) double (aortic and mitral) valve replacement. Valve repair was done in 42 (19.8%) patients, of which 41 were mitral and one aortic. Surgical mitral commissurotomy was performed in 25 (11.8%) patients. Thirty (14.1%) patients died in-hospital. In multivariable analysis, mortality was more than five times higher among patients who underwent double than single valve replacement {adjusted prevalence ratio (95% CI) = 5.65 (2.46-12.99), p < 0.001}. The patient’s age, disease duration, ejection fraction, surgical modality, pulmonary hypertension, intensive care unit stay were not predictors of mortality.

Conclusion: The in-hospital mortality observed in this study was higher than those reported in previous studies. In patients with RHD, double valve replacement is associated with increased early mortality, which may require greater technical expertise and careful postoperative management. Our findings need to be confirmed in prospective studies.