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Summary& Conclusion and RecommendationConventional mitral valve replacement MVR with complete excision of native valve apparatus has been associated with postoperative low output syndrome and a higher mortality.Maintenance of papillary annular continuity is important for ventricular geometry and function.The early and late hemodynamic benefits of preserving the mitral subvalvular apparatus during mitral valve replacement (MVR) have been demonstrated in several studies.The aim of this work is to evaluate left ventricular function after mitral valve replacement with preservation of posterior leaflet of mitral valve or total preservation of mitral valve tissue at rest and during peak exercise using dobutamine stress echocardiography (DSE).In this study, fifty patients undergoing isolated surgical correction of mitral insuf¬ficiency were prospectively randomized to either total or partial chordal sparing mitral valve replacement. Complete data from these 50 patients were available for analysis. Of these individuals, 25 had complete preservation of all chordal structures (C-MVR) (group I), and 25 had preservation of the posterior leaflet only (P-MVR) (group II).Left ventricular (LV) function was evaluated utilizing echocardiography preoperatively and postoperatively (3-6 month) at rest and during peak exercise using dobutamine stress echocardiography (DSE) to measure LVEDD (Left Ventricular End Diastolic Diameter), LVESD (Left Ventricular End Systolic Diameter), LVEF (Left Ventricular Ejection Fraction), LVFS (Left Ventricular Fraction Shortening), LAD (Left Atrial Diameter), CI (Cardiac Index), Co (Cardiac output). Effective Orifice Area (EOA), Maximum Pressure Gradient (Max PG), Mean Pressure Gradient (Mean PG).Preoperatively, there is no significant difference between both examined groups in age, sex, NYHA and echocardiographically.The aortic cross clamp time, total bypass time, was significantly longer in group I (C-MVR) compared to group II (P-MVR) as P < 0.001.Mechanical ventilation time, ICU stay time in hours, was significant longer in group I in relation to group II.Regarding need for inotropes and need for vasodilators intraoperative and in ICU, there was no significant difference between both examined groups.The total hospital stay, there was no significant difference between both examined groups.In patients of (group I) (C-MVR), regarding LVEF (Left Ventricular Ejection Fraction) and LVFS (Left Ventricular Fraction Shortening), There was no significant decrease between preoperative and postoperative at rest as P1 = 1, there was significant increase between preoperative and postoperative at stress and postoperative at rest & postoperative at stress as P2 & P3 < 0.001.There was significant difference between P1, P2 and P3 as total P < 0.00.In patients of (group II) (P-MVR), regarding LVEF (Left Ventricular Ejection Fraction), There was no significant difference between preoperative and postoperative at rest as P1 = 0.38, There was significant increase between preoperative and postoperative at stress and postoperative at rest & postoperative at stress as P2 = 0.007& P3 < 0.001 respectively. There was significant difference between P1, P2 and P3 as total P < 0.001. The LVFS (Left Ventricular Fraction Shortening), There was no significant difference between preoperative and postoperative at rest as P1 = 0.8, There was significant increase between preoperative and postoperative at stress and postoperative at rest & postoperative at stress as P2 = 0.001& P3 < 0.001 respectively. There was significant difference between P1, P2 and P3 as total P < 0.001.When comparing (group I) (C-MVR), and (group II) (P-MVR) statistically, Left Ventricular Ejection Fraction (LVEF), There was no significant difference postoperatively (at rest & stress) between both examined groups as P 1 = 0.13 and P 2 = 0.2 respectively. The differences (rest & stress) of both groups is not significant as total P = 0.13. Left Ventricular Fraction Shortening (LVFS), There was no significant difference postoperatively (at rest & stress) between both examined groups as P 1 = 0.17and P 2 = 0.3 respectively. The differences (rest & stress) of both groups is not significant as total P = 0.17.Regarding, EOA (Effective Orifice Area), Max PG (Maximum pressure gradient), Mean PG (Mean pressure gradient), There is no significant difference in all variable as P > 0.05.ConclusionPostoperative clinical and echocardiographic examinations demonstrate that beneficial effects were evident of preservation of mitral subvalvular apparatus either total or partial preservation.There was no statistically significant difference between both groups (total preservation and posterior preservation) as regard reduction in their LVEDD, LVESD, LAD, improvement of LVEF, and LVFS. Also, no significant difference in EOA, Max PG, Mean PG.On the other hand, significant improvement on left ventricular function between resting condition and stress condition was noticed in each group. But when comparing both groups, there was no significant difference between total preservation and posterior preservation 3 – 6 month after surgery.Recommendations1- MVR with chordal preservation either total or posterior should be considered for patients with chronic severe MR when mitral valve repair is not feasible.2- Partial or total chordal preservation should be tailored according to the condition of the diseased mitral valves at operation.3- The effect of the retained anterior mitral leaflet during MVR on the LVOT should be evaluated in another study.5- A randomized study on a bigger number of patients, and on a longer time postoperative should be done to compare the effect of partial and total chordal preservation on the left ventricular function after MVR for correction of chronic MR as some studies like yun et al, 2002 show the superiority of total preservation over posterior preservation on long term result.6- Smaller valve size should be studied and weighed against the value of preservation of the whole valve.
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