Early Outcome of Mitral Valve Replacement: Results from Chordal Preservation at Muhimbili National Hospital, Tanzania

Abstract

Background: Mitral Valve Replacement (MVR) is a common procedure for chronic Rheumatic Heart Disease (RHD) in developing countries. MVR may involve excision of chordae tendinae with leaflet(s) depending on the extent of pathology. Follow up of these patients reveals a progressive Left Ventricle (LV) dilatation, LV dysfunction and low cardiac output syndrome which has been attributed to the loss of annulo-ventricular continuity. Many studies revealed that, preservation of chordae tendinae has a significant role in maintaining post –operative normal LV size and function. The main objective of this study was to determine early outcome of mitral valve replacement among patients operated for Mitral Valve Replacement (MVR) with regards to chordal preservation at Muhimbili National Hospital

Patients and Methods: All patients admitted in the Cardiothoracic Unit, Muhimbili National Hospital for Mitral Valve Replacement from November 2011 to November 2013. Detailed echo was done pre-and post- operatively and New York Heart Association class (NYHA) assessment were recorded. Intra-operative valve assessment was done and categorized into; Total Chordal Excision (TCE), Posterior Mitral Leaflet (PML) preservation or Total Chordal Preservation (TCP). Patients were followed up at one month for control echo and NYHA assessment

Results: A total of 59 patients were recruited, male accounting for 31.7% and female 68.3% with age ranging from 10 years to 58 years. Indications for surgery were; severe mitral valve stenosis (MS)-33.2%, severe mitral valve regurgitation (MR)-35.6% and severe mixed mitral valve disease (MMVD)-32.2%. Among all patients, 45.8% had calcified leaflet(s) and 30.55% had atrial fibrillation. TCE was done in 22 patients (37.3%), PML in 21 patients (35.6%) and TCP in 16 patients (27.1%). There was a significant increase in End Diastolic Volume (EDV) and End Systolic Volume (ESV) with decrease in Ejection Fraction (EF) post- operatively in the TCE group (p=0.024, 0.001 and 0.000 respectively), a significant decrease in EDV and ESV in PML preservation (p=0.001 and 0.002 respectively), increase in EF (p=0.004) and a significant decrease in EDV in TCP group (p=0.008), increase in EF (p=0.016).

Conclusion and Recommendation
• Chordal Preservation in chronic rheumatic Mitral Valve Replacement is encouraged
• Chordal Preservation plays a significant role in the reduction of Left Ventricular volumes and improvement in ventricular function
• A larger scale study with longer follow up is required

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