Sakthivel, K (2009) Mitral Valve Replacement with Chordal Preservation: A Retrospective Analysis of Outcome in Comparison with Classical Mitral Valve Replacement. Masters thesis, Madras Medical College, Chennai.
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Abstract
INTRODUCTION : Rheumatic heart disease plays a major debilitating role in Indian population causing high morbidity and mortality, affecting the population in their productive phase of life. It impairs the quality of life and leads to psycho-social and economic burden to their family and the society. With the clinical introduction of cardiac valvular prosthesis in 1960, valve replacement has saved a number of lives affected by hemodynamically significant valvular heart diseases. Prosthetic valve replacement is not with out danger and it became evident that "valve replacement is simply exchanging one disease for another". In spite of tremendous strides toward perfecting materials and design, the ideal valve remains elusive. Thromboembolism continues to be a major cause of morbidity and mortality in patients who have undergone mechanical valve replacement. Recent surgical trend in treating rheumatic mitral valve disease is to repair the valve. If repair is not feasible, then valve replacement is still undertaken knowing the complications unique to prosthetic valve replacement in the interest of saving the life. It is well known that traditional mitral valve replacement when compared to mitral valve repair carries a higher morbidity and mortality. This has been attributed to the preservation of the mitral subvalvular apparatus in repair techniques, but not all valves can be repaired, especially those of rheumatic etiology. Mitral valve replacement has been the procedure of choice usually adopted in these conditions, but the results have not been comparable. By preserving the annular ventricular continuity in mitral valve repair good left ventricle (LV) function in both early and late post operative period has been achieved. A surgery in which annular-papillary continuity is preserved during replacement has shown better early and late results than traditional mitral valve replacement (MVR) techniques. As the awareness of the deleterious effects of the loss of annuloventricular continuity has increased chordal preservation during mitral valve replacement has gained in popularity. AIMS AND OBJECTIVES : The aim in this study was to study in retrospect the possible out come benefits of chordal sparing surgery when mitral valve replacement is done for rheumatic mitral disease in terms of left ventricular function by assessing parameters of left ventricular systolic and diastolic function. The parameters assessed were hemodynamic stability in the immediate peri and post operative period, left ventricular ejection fraction preoperative and postoperative, left ventricular end systolic and diastolic dimensions pre and postoperative . MATERIALS AND METHODS : All patients who underwent mitral valve replacement between January 2008 and December 2008 for isolated mitral valve disease are studied. Patients with other valvular (aortic, tricuspid & pulmonary) or congenital cardiac defects requiring additional intervention were excluded from the study. One hundred and fifty two patients underwent mitral valve replacement surgery for chronic mitral valve disease, in 86 of these procedures the classical mitral valve replacement technique was followed and in 66 patients chordal sparing technique was followed. In both group of patient’s preoperative NYHA class, left ventricular end systolic, end diastolic dimensions and preoperative ejection fraction were noted. Surgery was conducted with a standard midline sternotomy incision, bicaval and aortic cannulation. Core was cooled to 28°C. Heart was arrested with hyperkalemic blood cardioplegia, with topical ice slush being used to cool myocardial temperature further. Left atrium was opened parallel to the interatrial groove. Surgery was conducted after inspecting the valve and suitability for chordal preservation assessed. In all cases St Jude mechanical bileaflet prosthetic valve was used. Suturing was done with continuous / interrupted 2-0 ethibond suture in the classical mitral valve replacement patients or after plicating the posterior leaflet with the valve fixation suture in the posterior mitral leaflet area. All patients were electively ventilated post operatively with inotropic supports being dictated by the hemodynamics of the patient. The patients out come after surgery where the subvalvar apparatus was preserved either completely or partially were compared against the group in whom the classical technique was followed. The variables assessed were post operative needs for and dosage of multiple inotropic supports, duration of ventilator support. Post operative left ventricular function was assessed with a pre discharge echo cardiography. The parameters noted were the left ventricular end systolic and end diastolic dimensions post operative left ventricular ejection fraction, reduction in NYHA class. SUMMARY : One hundred and fifty two cases of mitral valve replacements were carried out between January 2008 and December 2008. Of these eighty six patients had classical mitral valve replacement surgery and sixty six patients had chordal sparing mitral valve replacement. Most of the patients operated were in NYHA class IV. Most of these patients affected were in the second decade with females outnumbering males. Ejection fraction preoperatively was normal or low normal in majority of patients with both classical mitral valve replacement and chordal sparring mitral valve replacement. One hundred and eight patients had preoperative atrial fibrillation. In chordal sparing mitral valve replacement group the need for prolonged postoperative ventilator support and higher inotropic supports was not seen. In the classical mitral valve replacement group 44 patients required prolonged ventilation support of greater than 24 hours. There were seven deaths in this series, two in the chordal sparing mitral valve replacement and five in the classical mitral valve replacement group. Postoperative echo showed a significant improvement in the ejection fraction and decrease in end systolic dimension in the chordal sparing mitral valve replacement group. CONCLUSION : Mitral valve replacement cannot normalize the life expectancy. Valve replacement has its own limitations. Valve replacement is not the end of the disease but a new beginning of a chronic disease lying dormant, ready to blow off at any time, given a chance. The best way to address this issue is to stress the importance of mass education, school health education, strict implementation of secondary prophylaxis and an early clinical trial for vaccines for rheumatic fever. In failed cases earlier intervention should be done and not to wait until the heart fails or atrial fibrilation sets in. Timely intervention when the valve is suitable for conservative procedures and to promote valve sparing surgery as much as possible, there by avoiding the prosthetic valve. In the established cases conservative surgery in the form of chordal preservation should be done with antiarrythymic surgery whenever possible. In our study of the 66 chordal sparing mitral valve replacement group, better hemodynamics were noted both in the immediate and early post operative period. Chordal sparing mitral valve replacement has been established to protect the left ventricular systolic and diastolic function in the late postoperative period. A well designed prospective trial with a larger group of patients and a longer follow up period is needed to evaluate further this technique.
| Item Type: | Thesis (Masters) |
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| Uncontrolled Keywords: | Mitral Valve Replacement ; Chordal Preservation ; Retrospective Analysis ; Outcome ; Comparison ; Classical Mitral Valve Replacement. |
| Subjects: | MEDICAL > Cardio Vascular and Thoracic Surgery |
| Depositing User: | Kambaraman B |
| Date Deposited: | 10 Nov 2017 17:55 |
| Last Modified: | 11 Nov 2017 02:33 |
| URI: | http://repository-tnmgrmu.ac.in/id/eprint/3884 |
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