Reoperation for Failure of Mitral Valve Repair in Degenerative Disease: A Single-Center Experience

Reoperation after early and late failure of mitral valve repair for degenerative disease

OBJECTIVES

To determine mechanisms of early and late failure after mitral valve repair for degenerative disease, identify factors associated with re-repair, and evaluate durability of re-repair.

METHODS

From January 2008 to July 2020, 330 reoperations were performed for recurrent mitral valve dysfunction after initial valve repair for degenerative disease. Mechanisms of repair failure were determined by review of preoperative imaging and operative reports. Multivariable analysis was performed to identify factors associated with likelihood of re-repair or replacement. Durability of re-repair was assessed using longitudinal analysis of postoperative echo data.

RESULTS

Eighty-five of 330 (26%) reoperations were performed for early repair failure within 1 year and 245/330 (74%) for late failure thereafter. Suture/annuloplasty dehiscence, systolic anterior motion, hemolysis, and ventricular remodeling were more common mechanisms of early failure and disease progression and fibrosis late failure. Forty percent (34/85) of early failures were re-repaired versus 24% (59/245) of late failures. Re-repair was more common than replacement in recent years and was associated with earlier reoperation (median 1.5 vs 3.9 years; P = .0001). No in-hospital deaths occurred after re-repair; 2 patients (0.8%) died after valve replacement. Freedom from severe mitral regurgitation after re-repair was 93% at 7 years.

CONCLUSIONS

Mitral valve re-repair can be performed with low rates of mortality and morbidity for early and late valve dysfunction. Mechanisms of early repair failure differ from those of late failure and are generally more amenable to re-repair. In selected patients who present after failed repair, we prefer mitral re-repair to valve replacement whenever technically feasible.

Repeat crossclamp after failed initial degenerative mitral valve repair is safe and successful

Objective

Surgical risk and long-term outcomes when re-crossclamp is required during degenerative mitral valve repair are unknown. We examined the outcomes of patients who required re-crossclamp for mitral valve reintervention.

Methods

Adults undergoing mitral valve repair for degenerative mitral valve disease at a single center from 2007 to 2021 who required more than 1 crossclamp for mitral valve reintervention were included. Outcomes including major morbidity and 30-day mortality were collected. Kaplan-Meier analysis characterized survival and freedom from recurrent mitral regurgitation.

Results

A total of 69 patients required re-crossclamp for mitral valve reintervention. Of those, 72% (n = 50) underwent successful re-repair and the remaining underwent mitral valve replacement (28%, n = 19). Major morbidity occurred in 23% (n = 16). There was no 30-day mortality, and median long-term survival was 10.9 years for those undergoing re-repair and 7.2 years for those undergoing replacement (P = .79). Midterm echocardiography follow-up was available for 67% (33/50) of patients who were successfully re-repaired with a median follow-up of 20 (interquartile range, 7-37) months. At late follow-up, 90% of patients had mild or less mitral regurgitation. Of those re-repaired, 2 patients later required mitral valve reintervention.

Conclusions

Patients requiring re-crossclamp for residual mitral regurgitation had low perioperative morbidity and no mortality. Most patients underwent successful re-repair (vs mitral valve replacement) with excellent valve function and long-term survival. In the event of unsatisfactory repair at the time of mitral valve repair, attempt at re-repair is safe and successful with the appropriate valvar anatomy.

Longitudinal Outcomes Following Surgical Repair of Primary Mitral Regurgitation

Degenerative mitral valve (MV) disease is the most common cause of organic mitral regurgitation (MR) in developed countries. Surgical mitral valve repair is the gold standard treatment for primary MR. Surgical mitral valve repair is associated with excellent outcomes in terms of survival and freedom from recurrent MR. As well, innovations in surgical repair techniques, including thoracoscopically and robotically assisted approaches, further reduce morbidity. Emerging catheter-based therapies may also provide advantages in select patient groups. Although the outcomes following surgical mitral valve repair are well described in the literature, longitudinal follow-up is heterogenous. Indeed, longitudinal follow-up and long-term data are vital to better advise treatment and counsel patients.

Re-repair vs. Replacement for Failed Mitral Valve Repair: A Systemic Review and Meta-Analysis

Objective

The objective of this study was to compare outcomes of re-repair with those of mitral valve replacement (MVR) for failed initial mitral valve repair (MVr).

Methods

We searched the Pubmed, Embase, and Cochrane Library databases for studies that compared mitral valve re-repair with MVR for the treatment of failed initial MVr. Data were extracted by two independent investigators and subjected to a meta-analysis. Odds ratio (OR), risk ratio (RR), hazard ratio (HR), ratio difference (RD), mean difference (MD), and 95% confidence interval (CI) were calculated with the Mantel-Haenszel and inverse-variance methods for mode of repair failure, perioperative outcomes, and follow-up outcomes.

Results

Eight retrospective cohort studies were included, with a total of 938 patients, and mean/median follow-up ranged from 1.8 to 8.9 years. Pooled incidence of technical failure was 41% (RD: 0.41; 95% CI: 0.32 to 0.5; P = 0.00; I2 = 86%; 6 studies, 846 patients). Pooled mitral valve re-repair rate was 36% (RD: 0.36; 95% CI: 0.26–0.46; P = 0; I2 = 91%; 8 studies, 938 patients). Pooled data showed significantly lower perioperative mortality (RR: 0.22; 95% CI: 07 to 0.66; I2 = 0%; P = 0.008; 6 studies, 824 patients) and significantly lower long-term mortality (HR:0.42; 95% CI: 0.3 to 0.58; I2 = 0%; P = 0; 7 studies, 903 patients) in the re-repair group compared with MVR.

Conclusions

Mitral valve re-repair was associated with better immediate and sustained outcomes for failed MVr and should be recommended if technically feasible.

Mitral valve re-repair vs replacement following failed initial repair: a systematic review and meta-analysis

Background

The optimal treatment strategy following a failed mitral valve repair remains unclear. This study aims to compare and analyse available studies which report the clinical outcomes post mitral valve re-repair (MVr) or replacement (MVR) after a prior mitral valve repair.

Methods

Based on PRISMA guidelines, a literature search was performed utilising PubMed, Cochrane and Scopus databases to identify retrospective cohort studies that reported outcomes of MVr and MVR after a prior mitral valve repair. Data regarding operative mortality, clinical outcomes and complications were extracted, synthesized and meta-analysed where appropriate.

Results

Eight studies with a total cohort of 1632 patients were used. After analysis, no significant differences in the short term and long-term operative mortality, incidence of stroke, congestive heart failure, Grade 1 and Grade 2 mitral regurgitation, requirement of 3rd mitral valve operation and reoperation due bleeding were found between the two groups. However, a slightly higher incidence of postoperative atrial fibrillation (OR: 0.11, CI: 0.02 to 0.17, I² = 0%, p = 0.02) was observed in the MVR group, as compared to the MVr group.

Conclusion

MVr appears to be a viable alternative to MVR for mitral valve reoperation, given that they are associated with similar post-operative outcomes.

Contemporary Reoperative Mitral Valve Surgery: Technical Considerations and Clinical Outcomes

As patients with cardiac disease live longer, reoperative mitral valve surgery has become more common. Although these operations are technically challenging and of high risk, outcomes continue to improve. Minimally invasive techniques, better cardioprotective strategies, and advanced perioperative care have contributed to this. In this review, we discuss surgical approaches, intraoperative strategies, novel catheter-directed devices, and clinical outcomes of contemporary reoperative mitral valve surgery.

The Neochord Procedure After Failed Surgical Mitral Valve Repair

Surgical mitral valve reintervention is associated with significant morbidity and mortality, and repeat repair is not always feasible. We examine the clinical outcomes of the NeoChord procedure after failed conventional mitral valve repair. A total of 312 patients were treated with the NeoChord repair procedure between January 2014 and December 2018 at 5 European centers. Clinical and echocardiographic data were reviewed to identify patients who had a prior surgical mitral valve repair procedure. The primary endpoint (Patient Success) was a composite of placement of at least 2 neochordae and end-procedure mitral valve regurgitation (MR) ≤ mild, freedom from death, stroke, structural or functional procedure failure (MR > moderate), procedure or device-related unplanned procedures, cardiac-related rehospitalization, or worsening NYHA functional class at 1 and 2-year FU. Fifteen (15) patients were identified who required reoperation for failed surgical mitral valve repair. Mean time-to-reoperation was 2.7 years (2.2-6.1). Median intensive care unit stay was 24 hours and median hospitalization time was 7 days (6-8). No in-hospital deaths were observed. At discharge, mitral regurgitation was ≤ mild in 13 patients (86.7%). Patient success and freedom from more than mild MR were 92.3 ± 7.4% and 83.9 ± 10.4% at 1 and 2-year follow-up respectively. One high-risk patient presented with severe recurrent MR and died during surgical reintervention due to an acute aortic dissection. Selected patients can be successfully treated with the NeoChord procedure after failed surgical mitral valve repair. These results support a wider adoption of the NeoChord procedure as a first-line minimally invasive, alternative therapy to treat failed mitral valve repair.

Re-repair of the failed mitral valve: insights into aetiology and surgical management

OBJECTIVES

Mitral valve (MV) repair is the gold standard for treatment of degenerative mitral regurgitation. A variety of surgical techniques allow surgeons to achieve a high rate of MV repair even with MV diseases of other aetiologies. However, a certain number of repairs fail over time. The aim of this study was to review our single-centre experience of MV re-repair and analyse the mode of repair failure, re-repair safety and efficiency in relation to the initial aetiology.

METHODS

Between 1997 and 2015, 91 patients underwent redo MV re-repair. The first MV repair was performed in our institution in 59% of cases. Follow-up information was available for 93% of our patients. The median follow-up was 56 months.

RESULTS

The initial aetiology was degenerative disease in 40 (44%) patients, rheumatic disease in 25 (27.5%), endocarditis in 10 (11%), ischaemic in 6 (7%), severe mitral annulus calcification in 5 (5.5%), congenital disease in 4 (4%) and unknown in 1 (1%). The mean age was 58 ± 15 years. The median delay between the 1st and 2nd repair was 49 months with 6 early re-repairs. Re-repair was urgent or emergent in 19% of cases; indications for surgery were mitral regurgitation in 48%, stenosis in 19%, endocarditis in 19%, mitral disease in 11%, ring thrombosis in 2% and systolic anterior motion in 1%. The main mechanisms of failure included technical error (30%), progression of disease (35%), new disease (29%) and unknown (6%.) Re-repair was performed through a median sternotomy in 96% of cases, and 34% of patients had concomitant procedures. Eight (9%) postoperative deaths (4 of mitral annulus calcification, 2 of endocarditis, 1 of degenerative disease, 1 of ischaemia) and 5 (6%) early failures occurred (3 of rheumatic disease, 1 of degenerative disease, 1 of a congenital condition), requiring MV replacement in 4 and new repair in 1. Overall survival at 5 and 10 years was 76% and 57%, 83% and 49% in patients with degenerative diseases and 95% and 95% in patients with rheumatic disease. Overall freedom from reoperation at 5 and 10 years was 82% and 61%, 94% and 87% with degenerative disease and 60% and 45% with rheumatic disease.

CONCLUSIONS

MV re-repair is feasible and has good mid-term results in patients with degenerative MV disease. Rheumatic MV disease is associated with a certain risk of failure over time; nevertheless, these patients show excellent survival after re-repair.

Causes of repair failure for degenerative mitral valve disease and reoperation outcomes

OBJECTIVES

This study aimed to evaluate the causes of initial mitral valve (MV) repair failure, the details of reoperation and the long-term outcomes of mitral valve re-repair (Re-MVP).

METHODS

We retrospectively reviewed 86 patients who underwent reoperation after MV repair for MR due to degenerative disease from October 1991 to December 2015. First, we analysed the initial MV repair data, causes of MV repair failure, reoperation data and long-term outcomes including survival. Second, the patients were classified into 2 groups based on valve related failure or procedure related failure , and the differences between the groups were analysed.

RESULTS

Leaflet prolapse at the initial operation affected the bilateral leaflets in 37 (43%) patients, the anterior leaflet in 30 (35%) patients and the posterior leaftlet in 19 (22%) patients. Median duration from first operation to reoperation was 47.5 (interquartile range 4.8-85.8) months. Reoperation indication included recurrent mitral regurgitation alone in 59 patients, haemolysis combined with recurrent mitral regurgitation in 15 patients, infectious endocarditis combined with recurrent mitral regurgitation in 8 patients, mitral stenosis in 2 patients and left ventricular pseudoaneurysm in 2 patients. The cause of MV repair failure was valve-related in 61 (71%) patients, procedure-related in 20 (23%) patients and both in 5 (6%) patients. Re-MVP was successful in 23 (27%) patients. Re-MVP was more common in patients with procedure-related failure, which occurred earlier than valve-related failure. Freedom from all-cause death was significantly better after Re-MVP. The 5-year freedom from reoperation after Re-MVP was 95.7%.

CONCLUSIONS

Re-MVP was more common in patients with procedure-related failure, which occurred earlier than valve-related failure. Durability of re-repaired MVs and survival of re-repaired patients were acceptable.

Long-Term Results Following Repair for Degenerative Mitral Regurgitation - Analysis of Factors Influencing Durability

BACKGROUND

The majority of patients with degenerative mitral regurgitation (DMR) are amenable to reconstructive procedures. There is debate regarding factors that influence long-term durability with respect to repair technique, valve remodelling and progressive myxomatous change.

METHODS

A total of 685 patients with DMR underwent mitral valve repair by a single surgeon between 1991 and 2011 with follow-up completed at 31 December 2016. Repair rate for patients undergoing surgery for DMR was over 90%. Mean age was 64 years (18-89) with 66.2% male, 47% NYHA class III-IV, and 20% had permanent atrial fibrillation (PAF). Major associated procedures were performed in 28% of patients (189); including coronary artery bypass graft (CABG) (127), aortic valve replacement (15), aortic root surgery (3) and tricuspid valve annuloplasty (61).

RESULTS

Operative mortality (≤30 days) occurred in four patients (0.58%). At 20 years, survival was 58%, freedom from reoperation was 90% and freedom from reoperation and non-operated recurrent MR >2+ (relapse) was 78%. Factors influencing survival were advancing age, left ventricular (LV) dysfunction (ejection fraction <60% or end systolic dimension >40mm), New York Heart Association (NYHA) III-IV and PAF. Predictors of relapse were the degree of residual intraoperative mitral regurgitation (p<0.001), anterior leaflet prolapse (p<0.001) and the addition of a sliding annuloplasty in isolated posterior leaflet repair (p=0.023). The majority of reoperations were for technical issues related to the original repair. A competent valve at 6 months to 3 years postoperatively predicted an excellent long-term result.

CONCLUSION

The great majority of degenerative mitral valves are repairable regardless of age with excellent long-term results achievable following surgery. Survival is reduced by significant symptoms, LV dysfunction and preoperative PAF. Repair is best performed before these features develop. Durability is largely dependent on the technical performance of the repair and degree of residual MR on the post-pump transoesophageal echocardiogram. We recommend surgery should be performed by surgeons specialising and skilled in mitral valve repair.

Outcome reporting for surgical treatment of degenerative mitral valve disease: a systematic review and critical appraisal

OBJECTIVES

Standardized outcome reporting is of critical importance for performance monitoring, improvement of existing techniques and introduction of novel technologies. Whether outcome reporting for surgical treatment of degenerative mitral valve disease complies with the guidelines has not been assessed to date.

METHODS

A systematic review of PubMed, EMBASE, Web of Science and the Cochrane Library was conducted for articles published between 1 January 2009 and 7 March 2016. Inclusion criteria were adult patient population (n ≥ 200) and surgical intervention for degenerative mitral valve disease. The quality of reported outcome was compared with the standard recommended by the guidelines on reporting morbidity and mortality after cardiac valve interventions.

RESULTS

Forty-two non-randomized clinical studies were included: 4 provided early and 38 provided early and late outcome data. Early echocardiographic outcome was reported in 49% of studies. Freedom from reintervention, the indication for reintervention and the follow-up echocardiographic outcome were reported in 97%, 59% and 79% of studies providing late outcome data, respectively. The Kaplan-Meier method was used to assess the freedom from recurrent mitral regurgitation in 60% (18/30) of studies, whereas 7% (2/30) of studies applied a longitudinal data analysis. Recurrent mitral regurgitation was most commonly defined as moderate (Grade 2+; 60%) or severe (Grade 4+; 37%) regurgitation.

CONCLUSIONS

There is a significant discordance between the guidelines-based recommendations and actual reporting of outcome for surgical treatment of degenerative mitral valve disease. Better adherence to the guidelines would raise the quality and generalizability of clinical data reporting.

Contemporary outcomes in reoperative mitral valve surgery

Objective

Data suggest that redo mitral valve surgery is being performed in increasing numbers, possibly with superior results according to single-centre studies. The purpose of this study is to describe outcomes of redo mitral valve surgery and identify risk-adjusted predictors of poor outcomes.

Methods

All (11 973) open mitral valve cases were evaluated (2002–2016) from a regional Society of Thoracic Surgery (STS) database. Patients were stratified by primary versus redo mitral valve surgery. Mixed effects logistic regression models including hospital as a random effect were used to identify risk factors for patients undergoing redo mitral valve surgery.

Results

Of all mitral valve cases, 1096 (9.7%) had a previous mitral operation. Redo patients had higher rates of valve replacement and preoperative comorbidities resulting in more complications, operative mortalities (11.1%vs6.5%, p<0.0001) and higher resource utilisation. Several factors independently increased risk for composite STS major morbidity and 30-day mortality, including cardiogenic shock (OR 10.3, p=0.0001), severe tricuspid insufficiency (OR 2.3, p=0.001), urgent/emergent status (OR 1.8, p=0.001) and concurrent coronary artery bypass grafting (OR 2.4, p=0.002). The volume of redo mitral valve surgery increased 10% per year and the observed-to-expected ratios (O/E) for operative mortality in redo mitral surgery improved from 1.44 early in the study period to 0.72 in the most recent era.

Conclusions

Redo mitral valve surgery accounts for approximately 10% of mitral valve operations and is associated with increased risk and resource utilisation. However, as the volume of redo mitral surgery increases, outcomes have dramatically improved and are now better than predicted.

Long-term outcomes of mitral valve repair versus replacement for degenerative disease: a systematic review

The short-term advantage of mitral valve repair versus replacement for degenerative disease has been extensively documented. These advantages include lower operative mortality, improved survival, better preservation of left-ventricular function, shorter post-operative hospital stay, lower total costs, and fewer valve-related complications, including thromboembolism, anticoagulation-related bleeding events and late prosthetic dysfunction. More recent written data are available indicating the long-term advantage of repair versus replacement. While at some institutions, the repair rate for degenerative disease may exceed 90%, the national average in 2007 was only 69%. Making direct comparisons between mitral valve repair and replacement using the available studies does present some challenges however, as there are often differences in baseline characteristics between patient groups as well as other dissimilarities between studies. The purpose of this review is to systematically summarize the long-term survival and reoperation data of mitral valve repair versus replacement for degenerative disease. A PubMed search was done and resulted in 12 studies that met our study criteria for comparing mitral valve repair versus replacement for degenerative disease. A systematic review was then conducted abstracting survival and reoperation data.

Outcome characteristics of multiple-valve surgery: comparison with single-valve procedures

OBJECTIVE

Multiple-valve (MUV) procedures currently exhibit higher operative mortality than do single-valve procedures, but a paucity of scientific information exists to explain the observation. This topic was examined using The Society of Thoracic Surgeons Database.

METHODS

All patients in the The Society of Thoracic Surgeons data set undergoing valve surgery (except pulmonary valve and aortic root operations) from 1993 through 2007 were identified (N = 623,039). Baseline characteristics and postoperative outcomes were contrasted between all seven combinations of single-valve and MUV procedures involving aortic, mitral, and tricuspid valves. Seven independent logistic regression analyses were performed, based on the seven procedures, and multivariable risk factors for mortality were compared, with emphasis on single-valve versus MUV procedures.

RESULTS

Baseline characteristics for MUV procedures (n = 67,926) shared many similarities to those for single-valve procedures (n = 555,113), including age, ejection fraction, and comorbidities. Preoperative renal failure, New York Heart Association class III to IV, nonelective presentation, and reoperation were slightly more common in MUV subsets, and coronary bypass was less frequent. Operative mortality was almost double for MUV as compared with single-valve procedures (10.7% vs 5.7%, P = 0.0001). Categorical predictors with the largest odds ratios for mortality were emergency status, renal failure, and second reoperation. However, predictors for mortality were generally consistent in order and magnitude between the single-valve and MUV subgroups.

CONCLUSIONS

Despite similarities in preoperative profiles of the patients undergoing single-valve and MUV procedures, mortality for MUV surgery remains considerably higher. Determinants of operative mortality and morbidity differ little across the procedural groups, and these findings serve as a benchmark for future studies, as well as suggest a continued search for explanations of poorer MUV outcomes.

Strain balance of papillary muscles as a prerequisite for successful mitral valve repair in patients with mitral valve prolapse due to fibroelastic deficiency

AIMS

The aim of this study was to assess the papillary muscle strain as a contributor to recurrent mitral regurgitation (MR) after mitral valve repair for fibroelastic deficiency.

METHODS AND RESULTS

Sixty-four patients with isolated posterior mitral valve prolapse and severe MR referred for surgery were prospectively recruited between 2008 and 2012. Two- and three-dimensional echocardiography and speckle tracking were performed in all patients. The longitudinal strain of the anterolateral (AL) and posteromedial (PM) papillary muscles was individually calculated as well as the global longitudinal strain of both papillary muscles was measured before and after mitral repair and normalized to left ventricle end-diastolic volume. Eight patients (12.5%) had at least moderate MR 6 months after mitral repair. The longitudinal strain of the AL (preop -4.94 ± 2.2 vs. postop -3.28 ± 1.3, P < 0.001) and the PM papillary muscles (preop -12.64 ± 5.3 vs. postop -4.12 ± 6.77, P < 0.001) as well as the global strain of both papillary muscles (preop -7.59 ± 3.48 vs. postop -1.07 ± 6, P < 0.001) were all reduced after surgical repair. The longitudinal strain of the PM papillary muscle was the strongest predictor of recurrent MR (when less than or equal to -14.78). The global preoperative papillary muscle strain was also a determinant of recurrent MR when the global strain was greater than -9.05% (area under the curve: 0.895, sensitivity: 100%, and specificity: 76.8%).

CONCLUSIONS

Patients with isolated posterior mitral leaflet prolapse are less likely having any residual MR post repair when the global papillary muscle strain of both papillary muscles is close or equal to zero. Strain of the papillary muscles may be an important determinant in predicting residual MR in patients who undergo mitral valve repair.

Regional annular geometry in patients with mitral regurgitation: implications for annuloplasty ring selection

BACKGROUND

The saddle shape of the normal mitral annulus has been quantitatively described by several groups. There is strong evidence that this shape is important to valve function. A more complete understanding of regional annular geometry in diseased valves may provide a more educated approach to annuloplasty ring selection and design. We hypothesized that mitral annular shape is markedly distorted in patients with diseased valves.

METHODS

Real-time 3-dimensional echocardiography was performed in 20 patients with normal mitral valves, 10 with ischemic mitral regurgitation, and 20 with myxomatous mitral regurgitation (MMR). Thirty-six annular points were defined to generate a 3-dimensional model of the annulus. Regional annular parameters were measured from these renderings. Left ventricular inner diameter was obtained from 2-dimensional echocardiographic images.

RESULTS

Annular geometry was significantly different among the three groups. The annuli were larger in the MMR and in the ischemic mitral regurgitation groups. The annular enlargement was greater and more pervasive in the MMR group. Both diseases were associated with annular flattening, although though the regional distribution of that flattening was different between groups. Left ventricular inner diameter was increased in both groups. However, relative to the Left ventricular inner diameter, the annulus was disproportionately dilated in the MMR group.

CONCLUSIONS

Patients with MMR and ischemic mitral regurgitation have enlarged and flattened annuli. In the case of MMR, annular distortions may be the driving factor leading to valve incompetence. These data suggest that the goal of annuloplasty should be the restoration of normal annular saddle shape and that the use of flexible, partial, and flat rings may be ill advised.

Re-repair of the mitral valve as a primary strategy for early and late failures of mitral valve repair

OBJECTIVES

With the expanding uptake of mitral valve repair as the primary therapy for mitral valve regurgitation, an increasing cohort of patients are presenting with failures following valve repair. These patients have traditionally been treated by mitral valve replacement. We have adopted an aggressive strategy of valve re-repair for failures of mitral valve repair and present our mid-term results.

METHODS

Fifty-three consecutive adults underwent reoperation by a single surgical team for failed non-rheumatic mitral valve repair. Primary valve repair had been done for degenerative (n=38), congenital (n=6), infective (n=3), functional (n=1) or unknown (n=5) mitral disease. The reoperative mitral procedure occurred at a median interval of 3 (interquartile range 0.9-6.5) years from the primary mitral valve repair. Valve re-repair was attempted if the anterior leaflet was sufficiently pliable, and lesions causing recurrence were identifiable and deemed treatable. Standard repair techniques were employed in re-repair procedures.

RESULTS

Valve analysis showed that the mode of failure was progression of original disease in 19 (36%), technical failure in 20 (38%) and new disease in 14 (26%) patients. Valve re-repair was successfully accomplished in 45 (85%) patients. Re-repair was most frequent when the prior aetiology was degenerative (34 of 38, 90%) as opposed to non-degenerative (11 of 15, 73%). There were no hospital deaths. Four-year patient survival was 97%. Freedoms from moderate mitral regurgitation were 100, 95, 88 and 80% at discharge and at 1, 3, and 4 years, respectively. There were no reoperations in the follow-up period.

CONCLUSIONS

Re-repair of the mitral valve is feasible in most of the cases of failed mitral valve repair of non-rheumatic aetiology and has acceptable mid-term outcomes. The relatively high prevalence of technical failures as the mechanism of failure of the primary mitral valve repair suggests the need for ongoing surgical education and continuing development and refinement of repair techniques.

Augmented mitral valve leaflet area decreases leaflet stress: a finite element simulation

BACKGROUND

Using human mitral valve (MV) models derived from three-dimensional echocardiography, finite element analysis was used to predict mechanical leaflet and chordal stress. Subsequently, valve geometries were altered to examine the effects on stresses of the following: (1) varying coaptation area; (2) varying noncoapted leaflet tissue area; and (3) varying interleaflet coefficient of friction (μ).

METHODS

Three human MV models were loaded with a transvalvular pressure of 80 mm Hg using finite element analysis. Initially leaflet coaptation was set to 10%, 50%, or 100% of actual coaptation length to test the influence of coaptation length on stress distribution. Next, leaflet surface areas were augmented by 1% overall and by 2% in the noncoapted "belly" region to test the influence of increased leaflet billowing without changing the gross geometry of the MV. Finally, the coefficient of friction between the coapted leaflets was set to μ = 0, 0.05, or 0.3, to assess the influence of friction on MV function.

RESULTS

Leaflet coaptation length did not affect stress distribution in either the coapted or noncoapted leaflet regions; peak leaflet stress was 0.36 ± 0.17 MPa at 100%, 0.35 ± 0.14 MPa at 50%, and 0.35 ± 0.15 MPa at 10% coaptation lengths (p = 0.85). Similarly, coaptation length did not affect peak chordal tension (p = 0.74). Increasing the noncoapted leaflet area decreased the peak valvular stresses by 5 ± 2% (p = 0.02). Varying the coefficient of friction between leaflets did not alter leaflet or chordal stress distribution (p = 0.18).

CONCLUSIONS

Redundant MV leaflet tissue reduces mechanical stress on the noncoapted leaflets; the extent of coaptation or frictional interleaflet interaction does not independently influence leaflet stresses. Repair techniques that increase or preserve noncoapted leaflet area may decrease mechanical stresses and thereby enhance repair durability.

Semi-automated mitral valve morphometry and computational stress analysis using 3D ultrasound

In vivo human mitral valves (MV) were imaged using real-time 3D transesophageal echocardiography (rt-3DTEE), and volumetric images of the MV at mid-systole were analyzed by user-initialized segmentation and 3D deformable modeling with continuous medial representation, a compact representation of shape. The resulting MV models were loaded with physiologic pressures using finite element analysis (FEA). We present the regional leaflet stress distributions predicted in normal and diseased (regurgitant) MVs. Rt-3DTEE, semi-automated leaflet segmentation, 3D deformable modeling, and FEA modeling of the in vivo human MV is tenable and useful for evaluation of MV pathology.

Mitral regurgitation: current trends in diagnosis and management

Mitral regurgitation is the most prevalent heart valve disorder in the United States. Individuals with mitral regurgitation may be asymptomatic or may present with dyspnea, orthopnea, fatigue, and/or heart rhythm disturbances. Long-standing mitral regurgitation causes chronic left ventricular volume overload, which leads to left ventricular dilation and contractile dysfunction. Without treatment, mitral regurgitation results in biventricular failure and death. Echocardiography is the preferred diagnostic test to assess the presence and severity of mitral regurgitation. Mitral valve surgery, the only effective treatment for patients with severe mitral regurgitation, is recommended early in the course of the disease to prevent the development of heart failure. Early recognition of mitral regurgitation and timely referral for mitral valve surgery significantly improve symptoms and long-term survival.

Mechanisms of recurrent regurgitation after valve repair for prolapsed mitral valve disease

BACKGROUND

We assessed mitral valve (MV) function using serial echocardiography as an indicator of the durability of MV repair. The aim of this study was to analyze the mechanisms of recurrent regurgitation after MV repair for degenerative disease.

METHODS

From 1991 to 2007, 736 patients had valve repair for mitral regurgitation caused by leaflet prolapse: 346 patients had posterior and 390 had anterior leaflet prolapse. The mean age was 54.6±14.6 years, with 495 males. The durability and mechanisms of recurrent regurgitation were evaluated by the findings of echocardiography and reoperation. Follow-up and late echocardiography averaged 5.7±3.9 and 5.1±3.6 years, respectively.

RESULTS

Survival was 91.9%±1.5% at 10 years. Freedom from reoperation and moderate or severe regurgitation at 10 years were 91.2%±1.7% and 84.5%±2.1%, respectively. Reoperations were performed for recurrent regurgitation in 29 patients, hemolysis in 5, and endocarditis in 1. Based on the findings of reoperation, the mechanisms of repair failure were procedure related in 9 (25.7%), valve related in 25 (71.4%), and unknown in 1. Late echocardiography revealed none to trivial regurgitation in 511 patients, mild in 153, moderate in 26, and severe in 40. Anterior leaflet prolapse, preoperative atrial fibrillation, and no use of annuloplasty ring were independent predictors of recurrent regurgitation. The main causes of moderate or severe regurgitation were leaflet thickening in 34 patients, leaflet prolapse in 20, dehiscence in 10, and unknown in 2.

CONCLUSIONS

The main mechanism of recurrent regurgitation after MV repair is progressive degeneration that is characterized by leaflet thickening and prolapse, especially in patients with anterior leaflet prolapse.