Reoperation after valve repair for mitral regurgitation: early and intermediate results

Successful mitral valve-in-ring repair of mitral annuloplasty ring dehiscence causing severe mitral regurgitation: a case report

BACKGROUND

Annuloplasty failure caused by ring dehiscence can lead to trans-ring and para-ring mitral regurgitation (MR). Transcatheter treatments are available for patients at prohibitive risk of surgery. In patients unsuitable for edge-to-edge repair, valve-in-ring (ViR) transcatheter mitral valve (MV) implantation has been described to treat trans-ring or para-ring jets but not both concurrently.

CASE SUMMARY

A 78-year-old male presented with severe MR due to dehiscence of a 34 mm Edwards Physio II mitral annuloplasty ring. Transoesophageal echocardiography showed two jets of regurgitation; trans-ring and para-ring. Repair was successfully undertaken with a ViR procedure (29 mm S3 Edwards Lifesciences).

DISCUSSION

Patients with failure of MV annuloplasty with trans-ring and para-ring regurgitation can be safely and effectively treated by ViR transcatheter MV implantation.

Reoperative Mitral Surgery Versus Transcatheter Mitral Valve Replacement: A Systematic Review

Bioprosthetic mitral structural valve degeneration and failed mitral valve repair (MVr) have traditionally been treated with reoperative mitral valve surgery. Transcatheter mitral valve-in-valve (MVIV) and valve-in-ring (MVIR) replacement are now feasible, but data comparing these approaches are lacking. We sought to compare the outcomes of (1) reoperative mitral valve replacement (redo-MVR) and MVIV for structural valve degeneration, and (2) reoperative mitral valve repair (redo-MVr) or MVR and MVIR for failed MVr. A literature search of PubMed, Embase, and the Cochrane Library was conducted up to July 31, 2020. Thirty-two studies involving 25 832 patients were included. Redo-MVR was required in ≈35% of patients after index surgery at 10 years, with 5% to 15% 30-day mortality. MVIV resulted in >95% procedural success with 30-day and 1-year mortality of 0% to 8% and 11% to 16%, respectively. Recognized complications included left ventricular outflow tract obstruction (0%-6%), valve migration (0%-9%), and residual regurgitation (0%-6%). Comparisons of redo-MVR and MVIV showed no statistically significant differences in mortality (11.3% versus 11.9% at 1 year, P=0.92), albeit higher rates of major bleeding and arrhythmias with redo-MVR. MVIR resulted in 0% to 34% mortality at 1 year, whereas both redo-MVr and MVR for failed repairs were performed with minimal mortality and durable long-term results. MVIV is therefore a viable alternative to redo-MVR for structural valve degeneration, whereas redo-MVr or redo-MVR is preferred for failed MVr given the suboptimal results with MVIR. However, not all patients will be candidates for MVIV/MVIR because anatomical restrictions may preclude transcatheter options from adequately addressing the underlying pathology.

Mitral valve leaflet response to ischaemic mitral regurgitation: from gene expression to tissue remodelling

Ischaemic mitral regurgitation (IMR), a frequent complication following myocardial infarction (MI), leads to higher mortality and poor clinical prognosis if untreated. Accumulating evidence suggests that mitral valve (MV) leaflets actively remodel post MI, and this remodelling increases both the severity of IMR and the occurrence of MV repair failures. However, the mechanisms of extracellular matrix maintenance and modulation by MV interstitial cells (MVICs) and their impact on MV leaflet tissue integrity and repair failure remain largely unknown. Herein, we sought to elucidate the multiscale behaviour of IMR-induced MV remodelling using an established ovine model. Leaflet tissue at eight weeks post MI exhibited significant permanent plastic radial deformation, eliminating mechanical anisotropy, accompanied by altered leaflet composition. Interestingly, no changes in effective collagen fibre modulus were observed, with MVICs slightly rounder, at eight weeks post MI. RNA sequencing indicated that YAP-induced genes were elevated at four weeks post MI, indicating elevated mechanotransduction. Genes related to extracellular matrix organization were downregulated at four weeks post MI when IMR occurred. Transcriptomic changes returned to baseline by eight weeks post MI. This multiscale study suggests that IMR induces plastic deformation of the MV with no functional damage to the collagen fibres, providing crucial information for computational simulations of the MV in IMR.

Optimized mitral annuloplasty ring design reduces loading in the posterior annulus

OBJECTIVE

The study objective was to develop a novel annuloplasty ring with regional flexibility and assess its suture force dynamics in healthy ovine subjects compared with fully rigid or fully flexible rings.

METHODS

Materially heterogeneous rings were created with rigid anterior and posterior, and flexible commissural segments. These rings were created to match the geometry of the Profile 3D ring (Medtronic, Minneapolis, Minn). Each ring was instrumented with 10 force transducers to measure cyclic suture forces (FC) and undersized annuloplasty was performed in 6 healthy ovine subjects. Each FC was recorded and examined for cardiac cycles reaching a maximum left ventricular pressure of 100, 125, and 150 mm Hg. FC was compared with previously reported values from fully rigid Profile 3D and fully flexible prototype rings.

RESULTS

Relative to the fully rigid ring, the heterogeneous ring exhibited 48% reduction in FC at its commissural (rigid vs heterogeneous: 1.80 ± 0.94 N vs 0.95 ± 0.52 N; P < .001) and 32% reduction in posterior (1.90 ± 0.92 N vs 1.29 ± 0.91 N; P < .001) regions, but not in its anterior region (2.45 ± 1.21 N vs 2.23 ± 1.22 N; P = .279). Relative to the fully flexible ring, the heterogeneous ring exhibited no significant differences in FC in any region.

CONCLUSIONS

The reduced FC of the heterogeneous ring relative to the fully rigid ring suggests a promising approach to reduce suture loading while preserving the annular remodeling capability of fully rigid rings. Future studies in diseased subjects are necessary to explore repair effectiveness of this ring.

Pathological Remodeling of Mitral Valve Leaflets from Unphysiologic Leaflet Mechanics after Undersized Mitral Annuloplasty to Repair Ischemic Mitral Regurgitation

Background Undersized ring annuloplasty is a commonly used surgical repair for ischemic mitral regurgitation, in which annular downsizing corrects regurgitation, but alters valve geometry and elevates tissue stresses. In this study, we investigated if unphysiological leaflet kinematics after annuloplasty might cause pathogenic biological remodeling of the mitral valve leaflets, and if preserving physiologic leaflet kinematics with a better technique can moderate such adverse remodeling. Methods and Results Twenty-nine swine were induced with ischemic mitral regurgitation, and survivors were assigned to groups: 7 underwent annuloplasty, 12 underwent annuloplasty with papillary-muscle approximation, 6 underwent papillary-muscle approximation, and 3 were sham controls. Pre-and post-surgery leaflet kinematics were measured, and valve tissue was explanted after 3 months to assess biological changes. Anterior leaflet excursion was unchanged across groups, but persistent tethering was observed with annuloplasty. Posterior leaflet was vertically immobile after annuloplasty, better mobile with the combined approach, and substantially ( P=0.0028) mobile after papillary-muscle approximation. Procollagen-1 was higher in leaflets from annuloplasty compared with the other groups. Heat shock protein-47 and lysyl oxidase were higher in groups receiving annuloplasty compared with sham. α- SMA was elevated in leaflets from animals receiving an annuloplasty, indicating activation of quiescent valve interstitial cells, paralleled by elevated transforming growth factor-β expression. Conclusions This is the first study to demonstrate that surgical valve repairs that impose unphysiological leaflet mechanics have a deleterious, pathological impact on valve biology. Surgeons may need to consider restoring physiologic leaflet stresses as well as valve competence, while also exploring pharmacological methods to inhibit the abnormal signaling cascades.

Suture dehiscence and collagen content in the human mitral and tricuspid annuli

Postoperative suture dehiscence is an important mode of short-term mitral and tricuspid valve (MV, TV) repair failure. We sought to evaluate suture pullout forces and collagen density in human atrioventricular valves for a better understanding of the comparative physiology between the valves and the underlying mechanobiological basis for suture retention. Mitral and tricuspid annuli were each excised from hearts from human donors age 60-79 with no history of heart disease (n = 6). Anchor sutures were vertically pulled until tearing through the tissue. Suture pullout force (F_P) was measured as the maximum force at dehiscence. Subsequently, tissue samples from each tested suture position were evaluated for collagen content using a standard hydroxyproline assay. Among all mitral positions, no significant differences were detected among positions or regions with mean F_P values falling between 6.9 ± 2.6 N (posterior region) and 10.3 ± 4.7 N (anterior region). Among all tricuspid positions, the maximum F_P and minimum F_P were 24.0 ± 9.2 N (trigonal region) and 4.5 ± 2.6 N (anterior region). Although for the MV, a given sample's collagen content had no correlation to its corresponding F_P, the same relationship was significant for the TV. Further, the TV exhibited comparable F_P to the MV overall, despite a nearly 40% reduction in collagen content. These findings suggest that sutures placed in the trigonal region of the TV have higher pullout force than those placed along other segments of the annuli. Furthermore, there are likely differences in collagen orientation between the mitral and tricuspid annuli, such that collagen content strongly impacts F_P in one, but not the other.

Mitral annuloplasty ring flexibility preferentially reduces posterior suture forces

Annuloplasty ring repair is a common procedure for the correction of mitral valve regurgitation. Commercially available rings vary in dimensions and material properties. Annuloplasty ring suture dehiscence from the native annulus is a catastrophic yet poorly understood phenomenon that has been reported across ring types. Recognizing that sutures typically dehisce from the structurally weaker posterior annulus, our group is conducting a multi-part study in search of ring design parameters that influence forces acting on posterior annular sutures in the beating heart. Herein, we report the effect of ring rigidity on suture forces. Measurements utilized custom force sensors, attached to annuloplasty rings and implanted in normal ovine subjects via standard surgical procedure. Tested rings included the semi-rigid Physio (Edwards Lifesciences) and rigid and flexible prototypes of matching geometry. While no significant differences due to ring stiffness existed for sutures in the anterior region, posterior forces were significantly reduced with use of the flexible ring (rigid: 1.95 ± 0.96 N, semi-rigid: 1.76 ± 1.19 N, flexible: 1.04 ± 0.63 N; p < 0.001). The ratio of anterior to posterior F_C scaled positively with increasing flexibility (p < 0.001), and posterior forces took more time to reach their peak load when a flexible ring was used (p < 0.001). This suggests a more rigid ring enables more rapid/complete force equilibration around the suture network, transferring higher anterior forces to the weaker posterior tissue. For mitral annuloplasties requiring ring rigidity, we propose a ring design concept to potentially disrupt this force transfer and improve suture retention.

Mitral annuloplasty ring suture forces: Impact of surgeon, ring, and use conditions

OBJECTIVE

The study objective was to quantify the effect of ring type, ring-annulus sizing, suture position, and surgeon on the forces required to tie down and constrain a mitral annuloplasty ring to a beating heart.

METHODS

Physio (Edwards Lifesciences, Irvine, Calif) or Profile 3D (Medtronic, Dublin, Ireland) annuloplasty rings were instrumented with suture force transducers and implanted in ovine subjects (N = 23). Tie-down forces and cyclic contractile forces were recorded and analyzed at 10 suture positions and at 3 levels of increasing peak left ventricular pressure.

RESULTS

Across all conditions, tie-down force was 2.7 ± 1.4 N and cyclic contractile force was 2.0 ± 1.2 N. Tie-down force was not meaningfully affected by any factor except surgeon. Significant differences in overall and individual tie-down forces were observed between the 2 primary implanting surgeons. No other factors were observed to significantly affect tie-down force. Contractile suture forces were significantly reduced by ring-annulus true sizing. This was driven almost exclusively by Physio cases and by reduction along the anterior aspect, where dehiscence is less common clinically. Contractile suture forces did not differ significantly between ring types. However, when undersizing, Profile 3D forces were significantly more uniform around the annular circumference. A suture's tie-down force did not correlate to its eventual contractile force.

CONCLUSIONS

Mitral annuloplasty suture loading is influenced by ring type, ring-annulus sizing, suture position, and surgeon, suggesting that reports of dehiscence may not be merely a series of isolated errors. When compared with forces known to cause suture dehiscence, these in vivo suture loading data aid in establishing potential targets for reducing the occurrence of ring dehiscence.

Mitral Valve Repair: Is There Still a Place for Suture Annuloplasty?

Prosthetic ring annuloplasty is considered the gold standard technique for mitral valve repair, but it has been associated with some drawbacks. Suture annuloplasty is less expensive and may have some physiopathologic advantages. We reviewed the literature to assess clinical results of mitral suture annuloplasty. Thirteen series, each reporting more than 50 patients and published in the last 10 years, were included in the analysis. They comprised 1,648 patients with cumulative follow-up of 5,607 patient-years. Our review suggests that suture annuloplasty is a safe procedure, but a trend toward recurrence of annular dilatation with time was reported. In selected cases, suture annuloplasty is effective, and its mid-term clinical results are encouraging and compare well with those of prosthetic ring repair series. The quality of the results varies according to the particular annuloplasty technique used and to the mitral valve pathology treated. Recent technical modifications have been found to decrease the incidence of repair failure and promise to improve the reproducibility of the procedure. Further investigations are warranted to better assess the long-term results of suture annuloplasty, and to determine whether its theoretical functional advantages translate into a real clinical benefit.

Effect of Recurrent Mitral Regurgitation Following Degenerative Mitral Valve Repair: Long-Term Analysis of Competing Outcomes

BACKGROUND

The risk for and consequences of recurrent mitral regurgitation (MR) following degenerative mitral valve repair are poorly understood.

OBJECTIVES

This study sought to examine recurrent MR risk along with reoperation and survival rates.

METHODS

We evaluated patients undergoing primary mitral repair for isolated degenerative MR over 1 decade. Median follow-up was 11.5 years (interquartile range: 9.2 to 13.6 years) and was 99% complete. Multivariate analysis of post-repair MR recurrence employed Cox proportional hazards and multistate modeling.

RESULTS

A total of 1,218 patients met the study criteria; the mean age was 64 ± 13 years, mean ejection fraction was 63 ± 9%, and 864 (71%) patients were men. Prolapse was posterior in 62%, bileaflet in 26%, and anterior in 12%. The 15-year incidence of recurrent MR (i.e., MR ≥2) was 13.3%, incidence of mitral reoperation was 6.9%, and overall mortality was 44.0%. Repair before 1996 independently predicted MR recurrence (hazard ratio: 1.52). Additional determinants were: age, mild intraoperative residual MR, anterior leaflet prolapse, bileaflet prolapse, perfusion time >90 min, and lack of annuloplasty. Recurrence of moderate or greater MR was associated with adverse left ventricular remodeling and increased likelihood of death (hazard ratio: 1.72). Among those undergoing repair after 1996, MR recurrence rate was 1.5 per 100 patient-years during the first year post-repair, decreasing markedly to 0.9 thereafter.

CONCLUSIONS

Our study demonstrated that recurrent MR following degenerative mitral valve repair is associated with adverse left ventricular remodeling and late death. The incidence of MR recurrence decreases markedly following the first year after intervention. A transparent discussion of recurrent MR risk has pressing relevance when referring patients with complex mitral valve prolapse.

Mitral Valve Replacement After Failed Mitral Ring Insertion With or Without Leaflet/Chordal Repair for Pure Mitral Regurgitation

Mitral repair operations for correction of pure mitral regurgitation (MR) are generally quite successful. Occasionally, however, the reparative procedure incompletely corrects the MR or the MR recurs. From March 1993 to January 2016, twenty nine patients had mitral valve replacement after the initial mitral repair operation, and observations in them were analyzed. All 29 patients at the repair operation had an annular ring inserted and later (<1 year in 6 and >1 year in 21) mitral valve replacement. The cause of the MR before the repair operation appears to have been prolapse in 16 patients (55%), secondary (functional) in 12 (41%) (ischemic in 5), and infective endocarditis which healed in 1 (3%). At the replacement operation the excised anterior mitral leaflet was thickened in all 29 patients. Some degree of stenosis appeared to have been present in 16 of the 29 patients before the replacement operation, although only 10 had an echocardiographic or hemodynamic recording of a transvalvular gradient; at least 11 patients had restricted motion of the posterior mitral leaflet; 10, ring dehiscence; 2, severe hemolysis; and 2, left ventricular outflow obstruction. In conclusion, there are multiple reasons for valve replacement after earlier mitral repair. Uniformly, at the time of the replacement, the mitral leaflets were thickened by fibrous tissue. Measurement of the area enclosed by the 360° rings and study of the excised leaflet suggest that the ring itself may have contributed to the leaflet scarring and development of some transmitral stenosis.

How Local Annular Force and Collagen Density Govern Mitral Annuloplasty Ring Dehiscence Risk

BACKGROUND

Annuloplasty ring dehiscence is a well described mode of mitral valve repair failure. Defining the mechanisms underlying dehiscence may facilitate its prevention.

METHODS

Factors that govern suture dehiscence were examined with an ovine model. After undersized ring annuloplasty in live animals (n = 5), cyclic force (FC) that acts on sutures during cardiac contraction was measured with custom transducers. FC was measured at ten suture positions, throughout cardiac cycles with peak left ventricular pressure (LVPmax) of 100, 125, and 150 mm Hg. Suture pullout testing was conducted on explanted mitral annuli (n = 12) to determine suture holding strength at each position. Finally, relative collagen density differences at suture sites around the annulus were assessed by two-photon excitation fluoroscopy.

RESULTS

Anterior FC exceeded posterior FC at each LVPmax (eg, 2.8 ± 1.3 N versus 1.8 ± 1.2 N at LVPmax = 125 mm Hg, p < 0.01). Anterior holding strength exceeded posterior holding strength (6.4 ± 3.6 N versus 3.9 ± 1.6 N, p < 0.0001). On the basis of FC at LVPmax of 150 mm Hg, margin of safety before suture pullout was vastly higher between the trigones (exclusive) versus elsewhere (4.8 ± 0.9 N versus 1.9 ± 0.5 N, p < 0.001). Margin of safety exhibited strong correlation to collagen density (R(2) = 0.947).

CONCLUSIONS

Despite lower cyclic loading on posterior sutures, the weaker posterior mitral annular tissue creates higher risk of dehiscence, apparently because of reduced collagen content. Sutures placed atop the trigones are less secure than predicted, because of a combination of reduced collagen and higher overall rigidity in this region. These findings highlight the inter-trigonal tissue as the superior anchor and have implications on the design and implantation techniques for next-generation mitral prostheses.

Reoperation after mitral valve repair in viewpoints of kidney injury as well as hemolytic anemia

A 70-year-old woman developed anemia and kidney injury 10 months after mitral valve (MV) repair. Serological findings and Doppler echocardiography suggested hemolytic anemia due to mitral regurgitation jet collision with an annuloplasty ring (MRCR). Since kidney injury persisted even without exacerbation of anemia over 10 months, we performed an MV replacement. The anemia improved rapidly after the surgery; however, the renal function remained chronic kidney disease (CKD) after reoperation. Kidney injury was thought to be due to iron deposition and decreased renal perfusion that caused tubular injury. A comprehensive literature review shows that hemolysis due to MRCR in the early postoperative phase (within 3 postoperative months) can be often ameliorated with endothelialization without the need for reoperation; however, hemolysis in the late postoperative phase can persist even for a long period without reoperation. Chronic hemolysis can lead to kidney injury and progress to CKD even without clinical evidence of exacerbation of anemia. Therefore, in cases of late postoperative phase hemolysis, reoperation should be considered for better management of kidney injury and hemolytic anemia.

Successful first-in-man Melody transcatheter valve implant in a dehisced mitral annuloplasty ring transapical valve-in-ring implant

AIMS

A "valve-in-ring" (ViR) procedure involves the transcatheter implant of a valved stent in a prosthetic mitral ring. The presence of a partial dehiscence of the prosthetic ring is a major contraindication for a ViR due to inefficacious sealing. We describe an alternative method of ViR implant to achieve proper valve sealing in the case of ring dehiscence.

METHODS AND RESULTS

A 76-year-old male patient suffered from severe central mitral regurgitation due to annuloplasty ring dehiscence and leaflet tethering. ECG-gated multidetector computed tomography was used for preoperative planning. Standard transapical access was gained through a minimally invasive left thoracotomy in the 5th intercostal space. A customised Melody valve with two PTFE sutures fixed to the apex was used. The intervention was performed without complications, the patient recovered well, and transthoracic echo revealed no mitral regurgitation through the implanted valve with a transvalvular gradient of 4 mmHg.

CONCLUSIONS

The implantation of a long covered stent such as the Melody valve allows successful sealing following a ViR even in case of partially detached annuloplasty rings. This procedure is a proof of concept that proper sealing can be achieved at the leaflet level without the use of radial force at the annular level.

Do all hemolytic anemias that occur after mitral valve repair require surgical treatment?

We report on a 29-year-old woman with severe hemolytic anemia following mitral valve annuloplasty. Although hemolysis due to mechanical prosthetic mitral valve is well recognized, hemolytic anemia associated with mitral valve repair is an uncommon condition. Reoperation may be considered if the patient has serious and persistent anemia. Although valve replacement is suggested to be a unique intervention, it may not be the solution every time because of mechanical effects. Various mechanisms of hemolysis related to mitral valve repair were suggested, but sufficient and precise data is not available. In this case, we tried to emphasize whether all hemolytic anemias that occur after mitral valve repair require surgical treatment.

Robotic mitral valve repairs in 300 patients: a single-center experience

OBJECTIVES

Mitral valve repair is the standard therapy for patients with degenerative (myxomatous) disease and severe mitral regurgitation. Robotic mitral valve repair provides the least-invasive surgical approach. We report the largest single-center robotic mitral valve repair experience.

METHODS

Between May 2000 and November 2006, 300 patients underwent a robotic mitral valve repair (daVinci Surgical System; Intuitive Surgical, Inc, Sunnyvale, Calif). All operations were done with 3- to 4-cm right intercostal access, transthoracic aortic occlusion, and peripheral cardiopulmonary bypass. Repairs included 1 or a combination of trapezoidal/triangular leaflet resections, sliding plasties, chordal transfers/replacements, edge-to-edge approximations, and ring annuloplasties. Echocardiographic and survival follow-up were 93% and 100% complete, respectively.

RESULTS

There were 2 (0.7%) 30-day mortalities and 6 (2.0%) late mortalities. No sternotomy conversions or mitral valve replacements were required. Immediate postrepair echocardiograms showed the following degrees of mitral regurgitation: none/trivial, 294 (98%); mild, 3 (1.0%); moderate, 3 (1.0%); and severe, 0 (0.0%). Complications included 2 (0.7%) strokes, 2 transient ischemic attacks, 3 (1.0%) myocardial infarctions, and 7 (2.3%) reoperations for bleeding. The mean hospital stay was 5.2 +/- 4.2 (standard deviation) days. Sixteen (5.3%) patients required a reoperation. Mean postoperative echocardiographic follow-up at 815 +/- 459 (standard deviation) days demonstrated the following degrees of mitral regurgitation: none/trivial, 192 (68.8%); mild, 66 (23.6%); moderate, 15 (5.4%); and severe, 6 (2.2%). Five-year Kaplan-Meier survival was 96.6% +/- 1.5%, with 93.8% +/- 1.6% freedom from reoperation.

CONCLUSIONS

Robotic mitral valve repair is safe and is associated with good midterm durability. Further long-term follow-up is necessary.

Late mitral annuloplasty failure: the loss of the ring

An 81-year-old man complained with increasing dyspnoea and asthenia few months after a successful double mitral and tricuspid valvuloplasty intervention. The echocardiogram revealed a partial detachment of the mitral annuloplasty ring due to dehiscence determining a severe regurgitation. Curiously, at Color-Doppler analysis of mitral inflow, the prolapse of the detached ring produced a fascinating circular line inside the regurgitation signal, mimicking the shape of a gemstone ring. We described a case of a relatively uncommon cause of late mitral valvuloplasty failure characterized by a really unusual echocardiographic finding.

Status of mitral valve surgery

PURPOSE OF REVIEW

To review the evolution of mitral valve repair and outline currently favored repair techniques.

RECENT FINDINGS

Chordal replacement with polytetrafluoroethylene sutures is an accepted and reproducible technique for repair of the anterior leaflet. Most posterior leaflet problems can be addressed with either a quadrangular resection or a sliding repair.

SUMMARY

Mitral valve surgery has gradually evolved over the period of the last 50 years. Initially, most surgeons replaced the mitral valve in patients with regurgitant disease. It is now known, however, that long-term outcome for patients undergoing repair is superior to that for patients undergoing replacement. Mitral valve repair avoids the complications associated with the artificial valve and anticoagulation. The ability to reproducibly repair the mitral valve requires a detailed knowledge of the disease process and the reparative techniques. This article describes the current approach to mitral valve surgery and the important concepts necessary to achieve a durable repair.

Neochordal repair of the posterior mitral leaflet

BACKGROUND

Myxomatous mitral valve insufficiency is traditionally repaired by posterior leaflet quadrangular resection and reconstruction. A simplified repair technique without leaflet resection is described, and our initial experience is reviewed.

METHODS

Thirty-nine consecutive patients with significant mitral regurgitation underwent repair since January 2000 by placement of expanded polytetrafluoroethylene sutures between the leading (coapting) edge of the posterior leaflet and the corresponding papillary muscle. An annuloplasty ring was placed, and no leaflet tissue was resected. Patient medical records were obtained and retrospectively reviewed.

RESULTS

Twenty-five men and 14 women (median age, 61 years; range, 40-88 years) had their mitral valve repaired by a variety of surgical approaches, including robotic (18 patients), right thoracotomy (6 patients), and sternal (15 patients). Three patients have required valve replacement: 1 at the initial operation, 1 because of dehiscence of the annuloplasty ring, and 1 after subsequent rupture of a previously normal native chorda. At follow-up (median, 12 months), 92% (33/36) of the remaining patients had an intact mitral repair with no to mild regurgitation, 8.3% (3/36) of patients had moderate regurgitation, and 92% of all patients (36/39) were in New York Heart Association class I. There were no deaths.

CONCLUSIONS

Myxomatous mitral regurgitation due to posterior leaflet insufficiency can be repaired without leaflet resection by placement of neochordae. This repair technique is effective and is readily accomplished by traditional and minimally invasive surgical approaches.

Outcome of mitral valve repair or replacement: a comparison by propensity score analysis

BACKGROUND

There are no randomized trials comparing outcomes after mitral valve (MV) repair and replacement. Propensity scoring is a powerful tool that has the potential to reduce selection bias in nonrandomized studies.

METHODS

From the BC Cardiac Registries, 2,060 patients presented for MV surgery, with or without CABG between 1991 and 2000. We then identified 322 MV repairs who were then matched by propensity score to an equal number of MV replacement patients. We compared survival and freedom from re-operation outcomes using Cox proportional hazards model analysis. Multivariable analysis was then used to compare outcomes in 358 MV repair patients with 352 MV replacement patients who had undergone chordal sparing surgery.

RESULTS

The comparison groups generated using propensity scores were well balanced with respect to all collected baseline risk factors. Median follow-up time was 3.4 years. Patients undergoing MV repair had significantly improved survival (RR 0.46; 95% CI, 0.28 to 0.75) but a trend toward more re-operations (RR 2.11; 95% CI, 1.00 to 4.47) compared with patients undergoing replacement. Mitral valve repair patients still had better survival (RR 0.52; 95% CI, 0.32 to 0.85) compared with MV replacement patients who had undergone chordal sparing surgery.

CONCLUSIONS

We used propensity score methods to reduce selection bias in a population-based cohort of patients undergoing MV repair/replacement. Repair was associated with better survival, but a trend to increased re-operation.

Reduction of hemolysis without reoperation following mitral valve repair

Hemolytic anemia following mitral valve repair and annular ring placement is uncommon compared with mitral valve replacement. A 60-year-old man, who had undergone mitral valve repair with a Duran ring, developed hemolytic anemia and needed a blood transfusion. Transesophageal echocardiography revealed a paravalvular mitral regurgitation jet colliding with the Duran ring. Most cases of severe hemolysis after mitral valve repair have undergone reoperation, but in the present case study, the hemolysis after mitral valve repair reduced without the need for reoperation, although the paravalvular mitral regurgitation jet continued to collide with the Duran ring.

Reoperation in mitral valve repair for regurgitant mitral valve disease

OBJECTIVES

Reviewing reoperative mitral valve repair, we evaluated a predictor for future reoperation by comparing degenerative and rheumatic mitral regurgitation.

METHODS

From June 1988 to September 2002, 159 patients with mitral valve regurgitation underwent a variety of surgical reconstruction. Our 9 subjects--2 men and 7 women with a mean age of 55.3 years--including 1 undergoing initial repair at an other hospital, underwent reoperation for mitral valve lesions. Four patients had rheumatic (Group R) and 5 degenerative (Group D) mitral valve disease. We studied reoperative outcomes and initial procedures were retrospectively.

RESULTS

The mean interval from initial repair was 111 months. Mitral valve lesions at reoperation in Group D were annular dilation in 3, leaflet prolapse in 1, and suture disruption in 1, while that in Group R involved severe thickening of both leafle. Rerepair was possible in 3 patients of Group D, but all others, (including Group R patients) required valve replacement. All survived reoperation.

CONCLUSIONS

Rerepair in rheumatic mitral regurgitation, rerepair was difficult. In degenerative mitral valve regurgitation, however, rerepair was possible because procedure-related origin was a major cause of reoperation. Reoperation can be prevented by proper technical improvement at initial repair.

Rerepair for recurrent mitral regurgitation due to Physio ring dehiscence

A 57-year-old man suffered recurrent mitral regurgitation after dehiscence of a 28 mm Physio ring 3 months after initial repair. We substituted a 30 mm Physio ring in reoperation, enabling successful mitral rerepair. This case points up the need for special care to be taken in determining the size of rigid rings and suture placement deep enough in annular tissue.

Detection of mechanisms of immediate failure by transesophageal echocardiography in quadrangular resection mitral valve repair technique for severe mitral regurgitation

Residual mitral regurgitation (MR) after repair is a risk factor for late reoperation. The use of intraoperative transesophageal echocardiography (IOTEE) decreases the incidence of immediate repair failure. This study identifies the mechanisms of immediate failure by IOTEE in the quadrangular resection technique, a well-standardized mitral valve repair procedure to guide further repair procedures. Two hundred five consecutive patients underwent quadrangular resection due to prolapse or flail posterior leaflet. Twenty-four patients (11%) had immediate failure. Immediate reinstitution of cardiopulmonary bypass ("second pump run") was needed in 21 patients (10%) for further repair. The identified mechanisms of failure were residual cleft provoking interscallop malcoaptation into the posterior leaflet in 8 patients, residual prolapse of the anterior or posterior leaflets in 1 and 4 patients, respectively, residual annular dilation in 3, left ventricular outflow obstruction in 2, suture dehiscence in 2, and other mechanisms in another 2 patients. In 20 patients (95%), IOTEE guided further repair with resolution of the residual MR, whereas 1 patient underwent valve replacement due to pharmacologically untreatable left ventricular outflow obstruction. In conclusion, even if this type of valve repair technique is well standardized, the incidence of immediate failure is not negligible. IOTEE identified the mechanisms of the immediate failure and guided further repair procedures, thus reducing the incidence of valve replacement (0.5%) without increasing perioperative mortality and morbility.

The long-term outcome of mitral valve repair for mitral valve prolapse

The rationale of early surgery for severe chronic mitral regurgitation (MR) due to mitral valve prolapse (MVP) has been developed over the past decade on the basis of the understanding of the natural history of this disease and the predictors of outcomes after surgical correction of MR. The important decrease in operative mortality associated with the advancements in myocardial preservation, and more importantly the improved reparability of the myxomatous mitral valve, were an additional incentive to develop the concept of early surgery. Previous studies showed that mitral valve repair offers a survival advantage at short- and 10-year follow-up, and therefore suggested that it should be the treatment of choice for severe MR due to MVP. Moreover, very recent data provided new insight on the very long-term follow up, ie, beyond the usual first 10 years in which the initial survival benefit of repair may be negated by a late deterioration.

The double-orifice technique for mitral valve reconstruction: predictors of postoperative outcome

OBJECTIVE

The 'double-orifice' (DO) technique has been recently proposed as an additional option in mitral valve repair (MVR). However, little is known regarding the long-term postoperative outcome and the predictors of DO results. Therefore, the aim of this study was to evaluate our clinical series and to identify prognostic factors of DO repair.

METHODS

From 1992, 75 patients underwent DO procedure because of severe mitral regurgitation. The study population consisted of 48 male and 27 female patients with a mean age of 58+/-13 years (range 16-80 years). The aetiology of mitral incompetence was Barlow disease in 30 cases, rheumatic disease in 18 cases, acute or healed endocarditis in 16 cases and other causes in 11 cases. Carpentier rigid ring was used in 38 patients, whereas autologous pericardium was used in 24 patients. Thirteen patients had no annuloplasty procedure. Statistical analysis included univariate and multivariate Cox proportional models to evaluate the predictors of the DO failure.

RESULTS

There were four hospital and three late deaths with a survival rate of 92% at 8 years. Mean follow-up was 42+/-24 months (range 1-93 months). Twelve patients underwent reoperation (five cases of early failure) and had valve replacement, leading to 80% freedom from reoperation at 8 years. At follow-up, 13 patients had no mitral regurgitation, 36 patients had trivial or mild mitral incompetence, whereas eight patients had moderate or severe mitral insufficiency at transthoracic echocardiography. Preoperative low left ventricular ejection faction, pulmonary arterial hypertension and marked left atrial enlargement were predictors (P<0.05) of DO failure at univariate analysis. Pericardial annuloplasty was also a risk factor (P<0.05) for unsuccessful DO repair at long term. Cox proportional multivariate analysis confirmed left atrial dilatation, pulmonary hypertension and pericardial annuloplasty as independent predictors of unfavourable postoperative results.

CONCLUSIONS

This study suggests that preoperative factors, like pulmonary hypertension and severe left atrial dilatation, may predict late DO failure. Our findings also indicate that pericardial annuloplasty may negatively influence mitral valve reconstruction at long term when DO is employed in MVR.

Pitfalls in surgical decision-making during mitral valve repair

Mitral valve repair has become the mainstay of surgical treatment for mitral valvular regurgitation. Surgeons in North America were relatively slow to adopt the various repair techniques, perhaps because rheumatic heart disease was less common, and the initial experiences with large numbers of repairs in Europe dealt largely with rheumatic disease. Subsequent experience, however, has clearly shown that patients with degenerative mitral valve disease can expect very durable repairs, and that most such patients have relatively simple pathologic conditions. The potential for repair, with a lack of need for long-term anticoagulation, has led to earlier surgical intervention. Still, mitral valve repair is far more complex than mitral valve replacement and must be accompanied by careful intraoperative decision making. Pitfalls exist that are different from those that accompany replacement. In this article, we examine some of the more common problems, their identification, and, hopefully, ways to avoid them.

Is a prosthetic ring required for mitral repair of mitral insufficiency due to posterior leaflet prolapse? Long-term results in 96 patients submitted to repair with no ring

OBJECTIVE

It is a common statement that every mitral repair should be stabilized by some type of prosthetic mitral ring. In the very specific situation of isolated prolapse of the posterior leaflet (PPL), this statement may be enhanced by the possible anatomically discontinuity of the mitral annulus. This article concerns 96 patients with 'isolated' PPL (IPPL) who were operated upon without ring insertion. Long-term follow-up was obtained in order to ascertain the survival, stability of the repair and the need for reoperation, thus justifying or not the lack of use of a ring.

METHODS

A total of 96 patients, 70 male and 26 female, underwent mitral repair for mitral insufficiency (MI) almost exclusively caused by PPL. Age ranged from 33 to 81 years (mean 60.7+/-11.3). All underwent quadrangular resection of the prolapsed portion and plication of the annulus. In 69 cases local stabilization was achieved by four U stitches, two on each side of the plication, passed through and sutured on some flexible material, 2-3 cm in length. Twenty seven patients had no such local reinforcement.

RESULTS

There was one case of early death (1%) caused by refractory hypoxemia in a patient with long lasting pre-operative pulmonary edema. Two patients were lost for follow-up after 2 months. Follow-up was from 0.2 to 14.7 years (mean 4.5), for a total of 422.7 patient-years. There were four late deaths at a mean of 6-year follow-up (0.9-10 years). Actuarial survival was 95.5 and 90.5% at 5 and 8 years, respectively. Event-free for recurrence of significant mitral insufficiency (MI) was 96 and 92% at 5 and 8 years. Event-free of thromboembolic or hemorrhagic events was 84.3 and 72.3% at 5 and 8 years. Event-free from reoperation was 97.8 and 94% at 5 and 8 years.

CONCLUSION

One can conclude that (a) IPPL repair without insertion of a ring is safe and long-lasting (b) the incidence of late death, recurrence of MI, thromboembolic/hemorrhagic events, need for reoperation, is not higher in this subset of patients than in conventional repair (c) such repair might work better and for a longer time, as reaction and sclerosis resulting from ring insertion are avoided (d) minor advantages could be due to an easier surgical procedure, especially through a minimally invasive approach.