Preservation of the posterior leaflet during mechanical valve replacement for ischemic mitral regurgitation and complete myocardial revascularization

The impact of complete versus partial preservation of the sub-valvular apparatus on left ventricular function in mitral valve replacement

INTRODUCTION

In mitral valve replacement (MVR), sudden increases in afterload and disruption of the annular-chordal-papillary-left-ventricular wall causes left ventricular (LV) dysfunction in the early postoperative period. Preservation of the posterior mitral leaflet apparatus (MVR-P) has a favorable outcome on LV function. However, there is paucity of data on the impact of complete preservation of the sub-valvular apparatus (MVR-C).

OBJECTIVE

We investigated the impact of MVR-P and MVR-C on baseline and 3-months postoperative LV ejection fraction (EF) and global longitudinal strain (GLS).

METHODS

We retrospectively analyzed a cohort of 29 MVR-P and 19 MVR-C patients with complete echocardiography data at our unit, who were operated between 2008 and 2017. Between-group changes in LVEF and GLS were compared using independent sample T-test.

RESULTS

Median age was 59 years (IQR 50-69 years). Baseline LVEF was 58% (51%- 60%). Baseline GLS was -18.4 (-21.2 to -15.5). There were no significant between-group differences between all baseline demographics and echocardiographic markers. There was significantly higher absolute postoperative LVEF in MVR-C patients (p = 0.029). There was also significant worsening in LVEF (p = 0.0121) and GLS (p < 0.0001) after MVR-P and not MVR-C, suggesting no reduction in LV function post-MVR-C but a reduction post-MVR-P. There was significantly less postoperative worsening of GLS per patient in MVR-C group as compared to the MVR-P group (p = 0.023), indicating better preservation of LV function. There was also a smaller decline in LVEF per patient in the MVR-C as compared to the MVR-P group, although not statistically significant (p = 0.23).

CONCLUSION

MVR with complete preservation of the sub-valvular apparatus shows a favorable impact on the longitudinal function of the heart at 3 months. Further studies with larger patient numbers are indicated to investigate the long-term results of this surgical approach.

Preservation versus non-preservation of mitral valve apparatus during mitral valve replacement: a meta-analysis of 3835 patients

Resection of the chordopapillary apparatus during mitral valve replacement has been associated with a negative impact on survival. Mitral valve replacement with the preservation of the mitral valve apparatus has been associated with better outcomes, but surgeons remain refractory to its use. To determine if there is any real difference in preservation vs non-preservation of mitral valve apparatus during mitral valve replacement in terms of outcomes, we performed a systematic review and meta-analysis using MEDLINE, EMBASE, CENTRAL/CCTR, SciELO, LILACS, Google Scholar and reference lists of relevant articles to search for clinical studies that compared outcomes (30-day mortality, postoperative low cardiac output syndrome or 5-year mortality) between preservation vs non-preservation during mitral valve replacement from 1966 to 2011. The principal summary measures were odds ratios (ORs) with 95% confidence interval and P-values (that will be considered statistically significant when <0.05). The ORs were combined across studies using a weighted DerSimonian-Laird random-effects model. The meta-analysis was completed using the software Comprehensive Meta-Analysis version 2 (Biostat Inc., Englewood, NJ, USA). Twenty studies (3 randomized and 17 non-randomized) were identified and included a total of 3835 patients (1918 for mitral valve replacement preservation and 1917 for mitral valve replacement non-preservation). There was significant difference between mitral valve replacement preservation and mitral valve replacement non-preservation groups in the risk of 30-day mortality (OR 0.418, P <0.001), postoperative low cardiac output syndrome (OR 0.299, P <0.001) or 5-year mortality (OR 0.380, P <0.001). No publication bias or important heterogeneity of effects on any outcome was observed. In conclusion, we found evidence that argues in favour of the preservation of mitral valve apparatus during mitral valve replacement.

Does preservation of the sub-valvular apparatus during mitral valve replacement affect long-term survival and quality of life? A Microsimulation Study

BACKGROUND

Techniques to preserve the sub-valvular apparatus in order to reduce morbidity and mortality following mitral valve replacement have been frequently reported. However, it is uncertain what impact sub-valvular apparatus preservation techniques have on long-term outcomes following mitral valve replacement. This study investigated the effect of sub-valvular apparatus preservation on long-term survival and quality of life following mitral valve replacement.

METHODS

A microsimulation model was used to compare long-term survival and quality-adjusted life years following mitral valve replacement after conventional valve replacement and sub-valvular apparatus preservation. Probabilistic sensitivity analysis and alternative analysis were performed to investigate uncertainty associated with the results.

RESULTS

Our Analysis suggests that patients survive longer if the sub-valvular apparatus are preserved (65.7% SD 1.5%, compared with 58.1% SD 1.6% at 10 years). The quality adjusted life years gained over a 10 year period where also greater after sub-valvular apparatus preservation. (6.54 QALY SD 0.07 QALY, compared with 5.61 QALY, SD 0.07 QALY). The superiority of preservation techniques was insensitive to patient age, parameter or model uncertainty.

CONCLUSION

This study suggests that long-term outcomes may be improved when the sub-valvular apparatus are preserved. Given the lack of empirical data further research is needed to investigate health-related quality of life after mitral valve replacement, and to establish whether outcomes differ between preservation techniques.

Serial radionuclide angiographic assessment of left ventricular ejection fraction and regional wall motion after mitral valve replacement in patients with rheumatic disease

BACKGROUND

This study was designed to prospectively investigate the effects of total or partial chordal-sparing and chordal-nonsparing mitral valve replacement (MVR) procedures on regional and global ventricular function in a rheumatic population using sequential multiple-gated acquisition scan.

METHODS

One hundred five consecutive patients undergoing different techniques of chordal preservation procedures during MVR are included in this prospective study. Fifteen patients had complete excision of the chordopapillary apparatus (group 1), 34 had total chordal preservation (group 2), and 56 had preservation of the posterior chordopapillary apparatus (group 3). Radionuclide-derived left ventricular ejection fraction (LVEF) and regional wall motion (RWM) studies on 99 survivors were performed preoperatively, at discharge, at 1 year, and at 2 years.

RESULTS

At discharge, there was a decline in LVEF in all the 3 groups. Statistically significant improvement in ejection fraction occurred in the chordal preservation groups (2 and 3) (P < .05) as compared with the nonchordal group immediately and late postoperatively. Only the total chordal group (2) demonstrated complete recovery of LVEF by 2 years postoperatively. Significant and persistent RWM abnormalities were noted in both the nonchordal and posterior chordal groups.

CONCLUSIONS

We conclude that complete retention of the chordopapillary apparatus during MVR provides superior results compared with nonchordal and partial chordal preservation in terms of preservation of LVEF and reduced incidence of abnormal postoperative RWM.

Trends in the surgical management of ischemic mitral regurgitation

The surgical approach to ischemic mitral regurgitation (IMR) remains a topic of considerable controversy. Will coronary artery bypass alone suffice, or should the valve be intervened upon? The poor late survival of patients with IMR is well recognized, but it remains unknown if this can be altered by addressing the valve directly. And if surgery is undertaken, should the valve be repaired or replaced? The underlying mechanisms of IMR remain incompletely understood, and although current theory focuses on the role of alterations in ventricular geometry in its pathogenesis, IMR is most often addressed by annuloplasty alone. Is this sufficient, or does the ventricle itself require "remodeling?" The debate is confounded by imprecise terminology that fails to distinguish between acute and chronic disease, and active ischemia from completed infarction. Available clinical information is from retrospective studies with all of their inherent limitations and potential for bias. Still, progress is being made as increasing attention is focused on this clinically important entity.

[Risk assessment of mitral valve surgery combined with myocardial revascularization]

INTRODUCTION AND OBJECTIVES

Patients with combined mitral valve operation and coronary artery surgery represent a high risk group. The aim of this retrospective study was to evaluate which factors affect early and late postoperative results in this particular group of considered high risk patients. PATIENTS AND METHOD. Between 1984 and 1997, 264 patients (mean age: 63 +/- 7.3 years) underwent mitral valve surgery (199 patients; 75% mitral valve replacement, 25% mitral valve repair) in combination with coronary revascularization (mean 2.4 +/- 1.3 grafts). Follow-up comprised a mean of 69 +/- 42 months and was 98.3% complete.

RESULTS

Early mortality was 10.6% (28/264). Ischemic mitral regurgitation operated on in emergent status, moderate to severe reduced left ventricular function and advanced age (> 60 years) were independently associated with early hospital mortality (p < 0.05). Ischemic etiology of mitral valve disease (emergency and elective operations), severity of mitral regurgitation and New York Heart Association (NYHA) functional class IV were related to early hospital mortality, only with univariate statistics. Actuarial survival was 86, 69 and 48% at 1, 5 and 10 years, respectively. The preoperative NYHA functional class was the only variable independently related to late survival. Eighty-five percent of the surviving patients were in NYHA functional class I and II.

CONCLUSIONS

Mitral valve operation combined with coronary artery bypass grafting is associated with a high early hospital mortality. Independent risk factors of early mortality are emergency operation of ischemic mitral valve disease, reduced left ventricular function and advanced age. Long term survival is independently influenced only by preoperative NYHA functional class IV.

Results of represervation of the chordae tendineae during redo mitral valve replacement

BACKGROUND

Previous studies have shown that preservation of the chordae tendineae improves early and late postoperative left ventricular function after mitral valve replacement. This report describes the results of represervation of the chordae tendineae during redo mitral valve replacement in patients who had their chordae tendineae preserved during their initial operation.

METHODS

Fifty-four patients undergoing reoperative mitral valve replacement with preservation of their chordal annular attachments (chordae group) were compared with 187 patients who had redo mitral valve replacement without preservation of the chordae (nonchordae group). The interval between the initial operation and the reoperation was 8.7 +/- 4.4 years in the chordae group and 8.6 +/- 4.9 years in the nonchordae group (p = 0.315). Seventy-three patients underwent aortic valve replacement during their redo mitral valve replacement compared with 168 patients who had mitral valve replacement alone. There were 15 patients who had their chordal attachments represerved during redo double-valve replacement.

RESULTS

In the chordae group, intraoperative assessment revealed excellent chordal connection between the preserved papillary muscles and the mitral annulus in all patients. One patient had adhesions between the preserved chordae and the stent of the tissue valve. The chordal attachments were preserved during insertion of the second valve in all patients. The incidence of low output syndrome and operative mortality in the chordae group was 16.7% and 7.4%, respectively. In the nonchordae group, the incidence of low output syndrome was 27.3% (p = 0.112 compared with the chordae group) and the operative mortality was 13.4% (p = 0.236 compared with the chordae group). In patients with double-valve replacement, represervation of the chordae was associated with a reduction in low output syndrome (0% versus 24%; p = 0.034) and mortality (6.7% versus 15.5%; p = 0.374).

CONCLUSIONS

Preservation of the chordal attachments between the papillary muscles and the mitral annulus can be accomplished during reoperative mitral valve replacement. Represervation of the chordae tendineae may reduce postoperative low output syndrome, especially in high-risk patients undergoing redo double-valve replacement.

Importance of preserving the mitral subvalvular apparatus in mitral valve replacement

BACKGROUND

This clinical study sought to determine whether mitral valve replacement (MVR) with the preservation of both anterior and posterior chordae tendineae (MVR group II) would be more effective on the improvement of left ventricular regional wall motion than MVR with the preservation of posterior chordae tendineae alone (MVR group I).

METHODS

Postoperative left ventricular wall motion was analyzed by a centerline method in three groups of MVR--group I (n = 13), group II (n = 15), and repair group (n = 15)--for mitral regurgitation. Shortening fraction of chordal length was determined in 100 chords, and these chords were divided into five regions.

RESULTS

The comparison of postoperative versus preoperative shortening fraction among the three groups revealed that postoperative wall motion improved more strikingly at apical and diaphragmatic regions in the MVR group II and repair group in comparison to the MVR group I. The postoperative shortening fraction at the apical region in the MVR group II was significantly increased in comparison to preoperative shortening fraction (preoperative, 3.68% +/- 1.87%; postoperative, 5.38% +/- 2.33%; p < 0.05). However, postoperative shortening fraction in cardiac base was decreased in the MVR group II as well as other two groups.

CONCLUSIONS

The MVR with the preservation of both anterior and posterior chordae tendineae contributed to the improvement of left ventricular regional wall motion in the apical and diaphragmatic regions.

Operation for acute postinfarction mitral insufficiency using continuous oxygenated blood cardioplegia

Patients with acute-onset mitral insufficiency and cardiogenic shock after myocardial infarction have a high incidence of operative death and morbidity. Patients with ventricular dysfunction, myocardial ischemia, and limited cardiac reserve undergoing an urgent operation represent a challenge to modern methods of myocardial protection. To improve results of operation a new technique was devised with continuous infusion of cold oxygenated blood cardioplegia during the entire cross-clamp period. Between 1984 and 1988, 19 consecutive patients with severe mitral regurgitation and cardiogenic shock (systolic blood pressure less than 60 mm Hg) after myocardial infarction underwent urgent myocardial revascularization, mitral valve replacement, or both. Left ventricular ejection fraction was less than 40% in 16 of 19 patients. All patients had suffered myocardial infarction within 4 weeks of operation and underwent an urgent operation within 24 hours of the onset of hemodynamic compromise. Severe three-vessel coronary artery disease was present in 16 of the 19 patients. A continuous infusion of blood cardioplegia was instituted at aortic cross-clamping and continued throughout the cross-clamp period. Infusion of continuous blood cardioplegia was also instituted through each completed distal vein graft. Myocardial septal and left ventricular apical temperatures were maintained at 10 degrees +/- 2 degrees C throughout the cross-clamp period. There were two in-hospital deaths (mortality, 10.5%) and low output syndrome was present in 10 patients (53%). At a mean follow-up of 2.5 years, there was one late death and 14 of the 16 remaining patients were in New York Heart Association functional class I or II.(ABSTRACT TRUNCATED AT 250 WORDS)

Current status of cardiac surgery: a 40 year review

Cardiac surgery has undergone dramatic advancements during the past 3 decades. The introduction of cardiopulmonary bypass and cardioplegic arrest ushered in the true era of open heart surgery. Bioprostheses and mechanical valves as well as techniques for valve reconstruction permit routine repair or replacement of stenotic and regurgitant native valves. Progress in the disciplines of mechanical and electrical engineering has led to the development of pocket watch-sized, physiologically responsive pacemakers as well as a variety of circulatory assist devices that include the intraaortic balloon pump, ventricular assist device and total artificial heart. The synthesis of cardiotonic and vasoactive drugs and advancements in anesthetic management, postoperative monitoring and nursing care greatly facilitate perioperative patient management. This summary of state of the art cardiac surgery begins with a brief historical background followed by a review of recent advances in six main categories: coronary artery disease, acquired valvular heart disease, congenital cardiac disease, cardiac transplantation, myocardial preservation and mechanical circulatory assistance. In conducting the review of recent literature, particular attention was directed to large clinical series that document the results of contemporary surgical procedures, novel therapeutic approaches to current clinical problems and unresolved controversies in the field of cardiac surgery. The abundance of surgical literature and constraints on the length of this article do not permit an exhaustive review. Apologies are extended to clinicians and laboratory investigators whose important contributions to the understanding and treatment of cardiac disease are not included herein.