Surgery For Ischemic Mitral Regurgitation Research Articles

Association of tricuspid regurgitation with clinical events and quality of life after surgery for severe ischemic mitral regurgitation

BackgroundThe clinical consequences of coexistent tricuspid regurgitation (TR) in patients with severe ischemic mitral regurgitation (IMR) remain unclear. We examined the association of baseline TR severity with outcomes after mitral valve (MV) surgery for IMR. MethodsWe conducted a secondary analysis of a randomized trial evaluating the effectiveness and safety of MV replacement versus repair for severe IMR. Patients were stratified by baseline TR (none/trace/mild vs moderate/severe). The primary endpoint was all-cause mortality. Secondary endpoints included major adverse cardiac and cerebrovascular events (MACCE) and quality of life (QoL) using the Minnesota Living with Heart Failure Questionnaire (MLHFQ). Cox proportional hazards and logistic models were used in the analysis. ResultsOf 251 randomized patients with severe IMR, 246 undergoing MV repair or replacement (123 each) were included in this secondary analysis. Sixty-one patients (25%) had ≥ severe TR, of whom 43% underwent MV repair and 57% underwent MV replacement. The 2-year all-cause mortality was significantly higher for those with moderate/severe TR compared to those with none/trace/mild TR (38% vs 16%; adjusted hazard ratio [aHR], 2.93; 95% confidence interval [CI], 1.59-5.38). MACCE rates were higher in patients with moderate/severe TR (53%) compared to those with none/trace/mild TR (39%) (aHR, 1.91; 95% CI, 1.21-3.03). No significant difference in 1-year QoL, measured as being alive with a 5-point improvement in the MLHFQ, was observed (odds ratio, 0.61; 95% CI, 0.28-1.33). ConclusionsIn patients undergoing surgery for severe IMR, preoperative moderate/severe TR was significantly associated with increased all-cause mortality and MACCE. Whether concomitant TV surgery would improve postoperative outcomes in patients with severe IMR and different degrees of TR should be evaluated in a randomized trial.

The high-risk features among patients undergoing mitral valve operation for ischemic mitral regurgitation: The 3-strike score

ObjectiveIschemic mitral regurgitation is prevalent and associated with high surgical risk. With the less-invasive option of transcatheter edge-to-edge repair, the optimal patient selection for mitral valve operation for ischemic mitral regurgitation remains unclear. We sought to identify high-risk features in this group to guide patient selection. MethodsUsing the Cardiothoracic Surgery Trial Network's severe ischemic mitral regurgitation trial data, we identified patient and echocardiographic characteristics associated with an increased risk of 2-year mortality using the support vector classifier and Cox proportional hazards model. We identified 6 high-risk features associated with 2-year survival. Patients were categorized into 3 groups, each having 1 or less, 2, or 3 or more of the 6 identified high-risk features. ResultsAmong the 251 patients, the median age was 69 (Q1 62, Q3 75) years, and 96 (38%) were female. Two-year mortality was 21% (n = 53). We identified 6 high-risk preoperative features: age 75 years or more (n = 69, 28%), prior sternotomy (n = 49, 20%), renal insufficiency (n = 69, 28%), gastrointestinal bleeding (n = 15, 6%), left ventricular ejection fraction less than 40% (n = 131, 52%), and ventricular end-systolic volume index less than 50 mL/m2 (n = 93, 37%). In patients who had 1 or less, 2, and 3 or more high-risk features, 90-day mortality was 4.2% (n = 5), 9.9% (n = 4), and 20.0% (n = 10), respectively (P = .006), and 2-year mortality was 10% (n = 12), 22% (n = 18), and 46% (n = 23) (P < .001), respectively. ConclusionsWe developed the 3-strike score by identifying high-risk preoperative features for mitral valve surgery for ischemic mitral regurgitation. Patients having 3 or more of such high-risk features should undergo careful evaluation for surgical candidacy given the high early and late mortality after mitral valve operations.

Multiple percutaneous coronary interventions worsen outcomes for subsequent surgical correction of chronic ischemic mitral regurgitation

ObjectiveWe investigated whether or not a history of multiple percutaneous coronary interventions (PCIs) is associated with clinical outcomes after surgery for ischemic mitral regurgitation. MethodsA total of 309 patients with chronic ischemic mitral regurgitation and left ventricular ejection fraction ≤40% who underwent restrictive mitral annuloplasty were classified as follows: patients with no or 1 previous PCI (nonmultiple PCI group [n = 211]) and patients with 2 or more previous PCIs (multiple PCIs group [n = 98]). Mean follow-up duration was 53 ± 40 months. ResultsBefore surgery, there were no intergroup differences in patient demographic characteristics except for lower estimated glomerular filtration rate in patients with multiple PCIs. These patients underwent concomitant coronary artery bypass grafting less frequently with a lower number of distal anastomoses (P < .05 for both). The 30-day mortality was 3.3% and 2.0% in the nonmultiple and multiple PCIs group, respectively (P = .72). During follow-up, there were 157 deaths. Patients with multiple PCIs showed lower 5-year survival rate (44% vs 64%; P = .002). After adjustments with inverse-probability-of-treatment weighting, multiple PCIs history was an independent risk factor for mortality (adjusted hazard ratio, 1.4; 95% confidential interval, 1.1-1.7; P = .002). Patients with multiple PCIs showed less improvement in left ventricular ejection fraction (interaction effect P < .001). ConclusionsIn patients with ischemic mitral regurgitation, a history of previous multiple PCIs was associated with increased risk of long-term postoperative mortality, with less improvement in left ventricular ejection fraction.

Predictors of hospital mortality after surgery for ischemic mitral regurgitation: the Toronto General Hospital experience.

The benefit of mitral valve repair (MVr) over replacement in patients with severe ischemic mitral regurgitation (IMR) is still controversial. We report our early postoperative outcomes of repair versus replacement. Data were collected for patients undergoing first-time mitral valve surgery for severe IMR between 1990 and 2009 (n = 393). Patients who underwent combined procedures for papillary muscle rupture, post-infarction ventricular septal defect, endocarditis, or any previous cardiac surgery were excluded. Preoperative demographics, operative variables, and hospital outcomes were analyzed, and multivariable regression analysis was employed to identify independent predictors of hospital mortality. Valve repair was performed in 42% (n = 164) of patients and replacement in 58% (n = 229). Patients who underwent replacement were older and had a higher prevalence of unstable angina, New York Heart Association Class IV symptoms, preoperative cardiogenic shock, preoperative myocardial infarction, peripheral vascular disease, renal failure, and urgent or emergency surgery (all p < .05). Unadjusted hospital mortality was higher in patients undergoing valve replacement (13% vs. 5%; p = .01). Valve repair was associated with a lower prevalence of postoperative low cardiac output syndrome. Multivariable analysis revealed that age, urgency of operation, and preoperative left ventricular (LV) function were independent predictors of hospital mortality. Importantly, MVr versus replacement was not an independent predictor of hospital mortality. Our data did not suggest an early survival benefit to MVr over replacement for IMR. However, age, LV dysfunction, and the need for urgent surgery were independently associated with hospital mortality.

Risk for non-home discharge following surgery for ischemic mitral valve disease

ObjectivesTo determine the frequency and risk factors for non-home discharge (NHD) and its association with clinical outcomes and quality of life (QOL) at 1 year following cardiac surgery in patients with ischemic mitral regurgitation (IMR). MethodsDischarge disposition was evaluated in 552 patients enrolled in trials of severe or moderate IMR. Patient and in-hospital factors associated with NHD were identified using logistic regression. Subsequently, association of NHD with 1-year mortality, serious adverse events (SAEs), and QOL was assessed. ResultsNHD was observed in 30% (154/522) with 25% (n = 71/289) in moderate and 36% (n = 83/233) in patients with severe IMR (unadjusted P = .006), a difference not significant after including age (5-year change: adjusted odds ratio [adjOR], 1.52; 95% confidence interval [CI], 1.35-1.72; P < .001), diabetes (adjOR, 1.94; 95% CI, 1.27-2.94; P = .002), and previous heart failure (adjOR, 1.64; 95% CI, 1.06-2.52; P = .03). Odds of NHD were increased for patients with postoperative SAEs (adjOR, 1.85; 95% CI, 1.19-2.86; P = .01) but not based on type of cardiac surgery. Greater rates of death and SAEs were observed in NHD patients at 1 year: adjusted hazard ratio, 4.29 (95% CI, 2.14-8.59; P < .001) and adjusted rate ratio, 1.45 (95% CI, 1.03-2.02; P = .03), respectively. QOL did not differ significantly between groups. ConclusionsNHD is common following surgery for IMR, influenced by older age, diabetes, previous heart failure, and postoperative SAEs. These patients may be at greater risk of death and subsequent SAEs after discharge. Discussion of NHD with patients may have important implications for decision-making and guiding expectations following cardiac surgery.

Tricuspid Regurgitation Associated With Ischemic Mitral Regurgitation: Characterization, Evolution After Mitral Surgery, and Value of Tricuspid Repair

Tricuspid regurgitation (TR) often accompanies ischemic mitral regurgitation and is generally assumed to be a secondary consequence of altered hemodynamics of the left-sided regurgitation. We hypothesized that it may also be a direct consequence of right-sided ischemic disease. Therefore, our objectives were to (1) characterize the nature of this TR and (2) describe its time course after mitral valve surgery for ischemic mitral regurgitation, with or without concomitant tricuspid valve repair. From 2001 to 2011, 568 patients with ischemic mitral regurgitation underwent mitral valve surgery. They had varying degrees of TR and altered right-side heart morphology and function; 131 had concomitant tricuspid valve repair. Postoperatively, 1,395 echocardiograms were available to assess residual and recurrent TR. Greater severity of preoperative TR was accompanied by larger tricuspid valve diameter, greater leaflet tethering, worse right ventricular function, and higher right ventricular pressure (all p [trend] ≤ 0.002). Without tricuspid valve repair, 31% of patients with no preoperative TR had moderate or greater TR by 5 years, as did 62% with moderate TR. With tricuspid valve repair, 25% with moderate preoperative TR remained in that grade at 5 years, but 11% had severe TR. Tricuspid regurgitation accompanying ischemic mitral regurgitation is associated with right-side heart remodeling and dysfunction often mirroring that occurring in the left side of the heart-ischemic TR. Tricuspid valve repair is effective initially, but as with mitral valve repair, TR progressively returns. Therefore, when the severity of TR and right-sided remodeling reaches the point of irreversibility, it may be an indication to eliminate the TR by replacing the tricuspid valve.

Ischemic mitral valve prolapse.

Ischemic mitral prolapse (IMP) is a pathologic entity encountered in about one-third among the patients undergoing surgery for ischemic mitral regurgitation (IMR). IMP is generally the result of a papillary muscle injury consequent to myocardial, but the recent literature is progressively unveiling a more complex pathogenesis. The mechanisms underlying its development regards the impairment of one or more components of the mitral apparatus, which comprises the annulus, the chordae tendineae, the papillary muscle and the left ventricular wall. IMP is not only a disorder of valvular function, but also entails coexistent aspects of a geometric disturbance of the mitral valve configuration and of the left ventricular function and dimension and a correct understanding of all these aspects is crucial to guide and tailor the correct therapeutic strategy to be adopted. Localization of prolapse, anatomic features of the prolapsed leaflets and the subvalvular apparatus should be carefully evaluated as also constituting the major determinants defining patient's outcomes. This review will summarize our current understanding of the pathophysiology and clinical evidence on IMP with a particular focus on the surgical treatment.

Concomitant Off-Pump Coronary Artery Bypass Grafting Results in Improved In-Hospital Outcomes for Patients with Ischemic Mitral Regurgitation Undergoing Surgery

Surgical management of ischemic mitral regurgitation (IMR) has primarily consisted of revascularization with or without the addition of mitral valve repair or replacement. We hypothesize that performing off-pump coronary artery bypass (OPCAB) grafting before fixing MR improves in-hospital outcomes for patients with IMR undergoing surgery. From January 2000 through December 2010, a total of 96 consecutive patients with moderate or severe IMR, as determined by preoperative echocardiography, underwent on-pump coronary artery bypass grafting (CABG) (n = 66) or OPCAB (n = 30) revascularization with concomitant mitral valve repair or replacement. A retrospective analysis of a prospectively collected cardiac surgery database (PATS; Dendrite Clinical Systems, Oxford, UK) was performed. In addition, medical notes and charts were reviewed for all study patients. The 2 groups had similar preoperative demographic and EuroSCORE risk-stratification characteristics. The operative mortality rate for the entire cohort was 9.4%. Patients who underwent OPCAB grafting had a lower operative mortality than those who underwent CABG (3.3% versus 12.1%; P = .006). The mean ±SD cardiopulmonary bypass time (82.7 ± 34.7 minutes versus 160.7 ± 45.2 minutes; P < .001) and cross-clamp time (49.0 ± 22.4 minutes versus 103.4 ± 39.5 minutes; P < .001) were significantly shorter in the off-pump group than in the on-pump group. The OPCAB group also had significantly less in-hospital morbidity and shorter stays in the intensive care unit and the hospital. Our analysis shows that OPCAB grafting (compared with conventional CABG) before repairing MR is associated with favorable in-hospital outcomes for patients undergoing surgery for IMR.

Functional mitral stenosis after surgical annuloplasty for ischemic mitral regurgitation: Importance of subvalvular tethering in the mechanism and dynamic deterioration during exertion

Diastolic subvalvular mitral leaflet tethering by left ventricular remodeling that restricts leaflet opening in the presence of annular size reduction by surgery for ischemic mitral regurgitation potentially causes functional mitral stenosis in the absence of organic leaflet lesions. Exercise, known to worsen systolic tethering and ischemic mitral regurgitation, might also dynamically exacerbate such mitral stenosis by increasing tethering. This study evaluates the mechanism and response of such mitral stenosis to exercise. We measured the diastolic mitral valve area, annular area, and peak and mean transmitral pressure gradient by echocardiography in 20 healthy individuals and 31 patients who underwent surgical annuloplasty for ischemic mitral regurgitation. Although the mitral valve area and annular area did not significantly differ in healthy individuals (4.7 +/- 0.6 cm(2) vs 5.2 +/- 0.6 cm(2), not significant), mitral valve area was significantly smaller than the annular area in patients after annuloplasty (1.6 +/- 0.2 cm(2) vs 3.3 +/- 0.5 cm(2), P < .01). The mitral valve area was less than 1.5 cm(2) only after the surgery (P < .01) and was significantly correlated with restricted leaflet opening (r(2) = 0.74, P < .001), left ventricular dilatation (r(2) = 0.17, P < .05), and New York Heart Association functional class (P < .05). Exercise stress echocardiography of 12 patients demonstrated dynamic worsening in functional mitral stenosis (mitral valve area: 2.0 +/- 0.5 cm(2) to 1.4 +/- 0.2 cm(2), P < .01; mean pressure gradient: 1.5 +/- 0.9 mm Hg to 6.0 +/- 2.2 mm Hg, P < .01). Persistent subvalvular leaflet tethering in the presence of annular size reduction by surgery in ischemic mitral regurgitation frequently causes functional mitral stenosis at the leaflet tip level, which is related to heart failure symptoms and can be dynamic with significant exercise-induced worsening.

Surgical Management of Ischemic Mitral Regurgitation

Case presentation: A 62-year-old man visited his cardiologist describing a 6-month history of increasing fatigue and shortness of breath on exertion. His medical history included an inferoposterior myocardial infarction (MI) 3 years previously that was treated with drug-eluting stents to his left circumflex and right coronary arteries. The result of physical examination was remarkable for crackles audible throughout the lower half of both lung fields, an elevated jugular venous pulse to the angle of the jaw, and a grade 3/6 holosystolic murmur loudest at the apex with radiation to the left axilla. An echocardiogram revealed a left ventricular ejection fraction (LVEF) of 15% to 20%, severe mitral regurgitation (MR), and a left ventricular end systolic dimension of 70 mm. The patient underwent a repeat cardiac angiogram that revealed patent stents in the circumflex and right coronary arteries and no other significant stenoses. The decision was made to surgically correct the patient’s MR with a mitral valve operation. He was brought to the operating room, where he was given general anesthesia, and a transesophageal echocardiogram was performed. Examination of the mitral valve revealed poor leaflet coaptation with a degree of leaflet tethering that resulted in severe MR. Inasmuch as the valve leaflets appeared structurally normal, a mitral valve repair procedure using a complete rigid annuloplasty ring was performed. A postoperative echocardiogram revealed trace MR, and the patient experienced no postoperative complications. This patient is a typical example of a growing problem in our aging population, namely, ischemic mitral regurgitation (IMR). IMR clearly has a negative impact on survival in patients with coronary artery disease, even in patients with mild to moderate MR; greater degrees of MR portend an even worse prognosis.1 With almost a fifth of patients who experience an MI followed by the development of IMR,2,3 and over …

Perioperative Predictors for Recurrence of Mitral Regurgitation after Surgery for Ischemic Mitral Regurgitation

Background and Objectives：In clinical practice, significant recurrence of mitral regurgitation (MR) is observed frequently even after surgical treatment for ischemic MR (IMR). The purpose of this study is to evaluate the recurrence rate of MR and to investigate perioperative predictors for its recurrence following surgery for IMR. Subjects and Methods：We retrospectively analyzed 106 patients who underwent surgical management for IMR. Echocardiographic parameters, such as severity of MR, ejection fraction, diastolic left ventricular (LV) dimension, systolic LV dimension, left atrial size, LV sphericity index, mitral valve (MV) tenting area, MV tenting height (TH), tethering distance, MV intraleaflet angle (MVILa), and MV intraleaflet height (MVILh) were measured. Results：Two types of surgery were performed to treat IMR, including valvuloplasty combined with coronary artery bypass graft (CABG)(group A, n=79) and LV volume reduction surgery combined with CABG (group B, n=27). Significant MR was detected echocardiographically 5.4±6.7 months after the surgery. The overall recurrence rate of MR was 17% (n=18), and 15.2% (n=12) in group A and 22.2% (n=6) in group B. The preoperative TH and the postoperative MVILh were independent perioperative predictors for the recurrence of significant MR according to multiple logistic regression analysis (p<0.05, respectively). Conclusion：The overall postoperative recurrence rate of significant MR after surgical repair is 17% within 6 months. Independent perioperative predictors of recurrent MR after surgery for IMR are the preoperative TH and the postoperative MVILh. For better outcomes in IMR management, those two factors should be considered in the surgical repair of IMR. (Korean Circulation J 2006;36:753-761)

Geometric change of mitral valve leaflets and annulus after reconstructive surgery for ischemic mitral regurgitation: Real-time 3-dimensional echocardiographic study

Ischemic mitral regurgitation (IMR) is a functional regurgitation characterized by structurally normal leaflets and subvalvular apparatus and is an important complication after myocardial infarction that is associated with excess mortality. 1 Reconstructive surgery, which restores a more normal alignment between the mitral annulus and displaced papillary muscles, might be beneficial in patients with IMR. However, little is known about the 3-dimensional (3-D) geometric changes of mitral leaflets and annulus after such reconstructive surgery for patients with IMR. We developed novel software, named Anatomical Image Creation System (AICS), which allows 3-D visualization and quantitative analysis of the mitral leaflets and annulus by using transthoracic real-time 3-D echocardiography (RT3DE). 2 We already demonstrated the apparent tenting of the mitral leaflets with flattened annulus in patients with IMR using this system. 3 In the present study we evaluated the 3-D geometric changes of the mitral leaflets and annulus in patients after reconstructive surgery for IMR using AICS. Methods We studied 3 patients who underwent mitral ring annuloplasty and concomitant left ventricular (LV) restorative surgery for severe IMR and severe LV systolic dysfunction caused by coronary artery disease. All the RT3DE examination was performed 1 week before and 3 weeks after the operation. LV systolic function and degree of mitral regurgitation (MR) were quantified by using 2-dimensional echocardiography. Using the transthoracic volumetric image by the RT3DE system with AICS, we created 3-D images of the mitral leaflets and annulus in midsystole for the 3-D quantitative measurements. The mitral leaflets’ tenting volume was calculated as a volume enclosed between the 3-D annular plane and the mitral leaflets. Mitral annular size was measured by using those 3-D data sets as well (surface area, circumference, commissure-commissure diameter, and anterior-posterior diameter). Details of the 3-D image creation and measurements are described in our previous reports. 2,3 All 3 patients provided written informed consent to the study protocol, which was approved by the Committee for the Protection of Human Subjects in Research at Kawasaki Medical School.

Noncardioplegic surgery for ischemic mitral regurgitation.

Twenty-seven consecutive patients underwent surgery for ischemic mitral regurgitation (MR): papillary muscle rupture (1), papillary muscle dysfunction (11) and annular dilatation (15). The grade of MR was moderate or severe, and the ejection fraction (EF) was less than 30% in 8 patients (mean, 43%). Three cases were reoperation and 3 were emergencies. Under ventricular fibrillation (VF) and intermittent aortic cross-clamping at moderate hypothermia, coronary artery bypass grafting (CABG) was performed first, followed by the mitral procedure through a right-sided left atriotomy (repair 21, replacement 6) performed under VF with the heart perfused through the native coronary arteries and CABG grafts. Concomitant procedures were CABG (23), Dor's procedure (5), and tricuspid annuloplasty (3). In one reoperative case with cardiogenic shock, CABG was impossible because of dense adhesions and the patient died just after surgery (hospital mortality, 3.7%). Five patients required intra-aortic balloon pump (IABP) support intraoperatively, but none required prolonged (> or =7 days) inotropic support or IABP use, although the serum concentrations of creatine kinase and its myocardial fraction were elevated remarkably. Other morbid events were refractory ventricular arrhythmia in one case and stroke in another. Median duration of mechanical ventilation and intensive care unit stay was 8 h and 3 days, respectively. Mean EF at hospital discharge was 48%. The extended period of VF was not associated with unfavorable clinical outcomes. Noncardioplegic surgery for ischemic MR was carried out with acceptable mortality and morbidity, and can be a good alternative, especially when clamping the aorta is undesirable.

Cirugía de la insuficiencia mitral isquémica

Ischemic mitral regurgitation (IMR) is a severe condition which may be best treated by surgery, notwithstanding a relatively high mortality rate. To evaluate the results of mitral valve replacement or repair in patients with IMR. Retrospective review of the clinical records in 29 patients with IMR who were surgically treated from 1990 to 1999. They represent 8% of surgical procedures on the mitral valve. Mean age was 67 +/- 9 years. Surgery was performed urgently in 19 patients (66.5%). NYHA functional class was 3.4 +/- 0.8. The mechanism of IMR was annular dilatation and spreading of papillary muscles in 18 patients, papillary muscle rupture in 9 and fibrosis in 2. Mitral valve replacement was performed in 14 patients and mitral valve repair in 15. Twenty four patients (83%) had concomitant myocardial revascularization. Overall surgical mortality was 24%; 26% for mitral replacement and 13% for mitral valve repair (p = 0.215). On follow up of 26 +/- 33 months, one year survival was 76 +/- 0.8% and 5 years survival was 59 +/- 12%. Excluding in hospital mortality, survival was 100% at one year and 78 +/- 14% at 5 years. Functional class improved in all survivors, to 1.4 +/- 0.5. Late echocardiographic evaluation of patients with mitral valve repair showed absence of mitral regurgitation in 58%, 1+ MR in 17% and 2+ MR in 25%. In spite of a high perioperative mortality, surgery for IMR is a valuable procedure for patients with an otherwise highly lethal disease.

Is repair preferable to replacement for ischemic mitral regurgitation?

Objective: This study was undertaken to compare mitral valve repair and replacement as treatments for ischemic mitral regurgitation. Methods: From 1985 through 1997, a total of 482 patients with ischemic mitral regurgitation underwent either valve repair (n = 397) or valve replacement (n = 85). Patients more likely (P ≤.01) to undergo repair had functional mitral regurgitation or coronary revascularization with an internal thoracic artery graft; those more likely to receive valve replacement were in higher New York Heart Association functional classes or underwent emergency operations. These factors were used for multivariable propensity matching. Risk factors for early and late death were identified by multivariable, multiphase hazard function analysis. Results: Within the propensity-matched better-risk group, survivals after valve replacement were 81%, 56%, and 36% at 30 days, 1 year, and 5 years, but survivals after repair were 94%, 82%, and 58% at these intervals (P =.08). In contrast, within the poor-risk group, survivals after repair and replacement were similar (P =.4). Risk factors (P ≤.01) included older age, higher functional class, greater wall motion abnormality, and renal dysfunction. Approximately 70% of patients were predicted to benefit from repair; the benefit lessened or was negated if an internal thoracic artery graft was not used, if a lateral wall motion abnormality was present, or if the mitral regurgitation jet pattern was complex. Freedom from repair failure at 5 years was 91%. Conclusion: Late survival is poor after surgery for ischemic mitral regurgitation. Most patients with ischemic mitral regurgitation benefit from mitral valve repair. In the most complex, high-risk settings, survivals after repair and replacement are similar.