The outcome and criteria for mitral valve surgery in patients with ischemic mitral regurgitation

Objectives: Mitral valve surgery for the correction of mitral regurgitation (MR) in patients with ischemic heart disease has been associated with poor prognosis. The criteria for selecting an appropriate surgical procedure are not clearly defined. The objectives of this study were to clarify the criteria for mitral valve manipulation and the outcome in patients with ischemic MR.Methods: Twenty patients with ischemic MR were proposed for surgery. Ten of them (group A) had grade II MR and underwent isolated coronary artery bypass grafting (CABG). The remaining 10 patients with grade III or more MR underwent both CABG and mitral valve repair (group B). Postoperative left ventricular function and outcome were compared.Results: Preoperative left ventricular end-systolic volume index (LVESVI) in group A was significantly smaller, while preoperative ejection fraction (EF) was almost equal between the groups. EF demonstrated a significant improvement in group A postoperatively, but no changes in group B. Two of group B died following surgery. The other patients were successfully treated with surgery which diminished MR. Congestive heart failure (CHF) developed in 2 patients of group B during follow-up and in none of group A. The 5-year freedom from CHF and the 5-year survival rate in group A were significantly greater than those in group B.Conclusions: Deterioration of mitral valve function, which necessitated mitral valve repair, was more frequent in the impaired and enlarged hearts. Although mitral repair was beneficial for diminishing MR and New York Heart Association, postoperative course in patients with ischemic MR depended on the preoperative LVESVI.     

Patient survival characteristics after routine mitral valve repair for ischemic mitral regurgitation

BACKGROUND: Ischemic mitral regurgitation has been associated with diminished survival compared with nonischemic mitral regurgitation. Conversion from mitral valve replacement to valve repair has improved prognosis, but it is unclear whether ischemic mitral regurgitation remains an independent predictor of outcome after mitral valve repair. METHODS: Five hundred thirty-five patients undergoing mitral valve repair (primarily rigid ring annuloplasty) with or without coronary bypass from 1993 through 2002 were reviewed retrospectively (ischemic mitral regurgitation, n = 141; nonischemic mitral regurgitation, n = 394). A Cox proportional hazards model evaluated survival as a function of 9 simultaneous covariates: ischemic versus nonischemic mitral regurgitation, age, sex, number of medical comorbidities, ejection fraction, New York Heart Association class, coronary disease, reoperation, and year of operation. RESULTS: According to univariable analysis, patients with ischemic mitral regurgitation had greater age, higher comorbidity, lower ejection fraction, higher New York Heart Association, and higher reoperation rate (all P < .001) compared with those having nonischemic mitral regurgitation. Univariable 30-day mortality was as follows: 4.3% for patients with ischemic mitral regurgitation versus 1.3% for patients with nonischemic mitral regurgitation (P = .01). Unadjusted 5-year mortality was as follows: 44% +/- 5% for patients with ischemic mitral regurgitation versus 16% +/- 3% for patients with nonischemic mitral regurgitation (P < .001). In the multivariable model, however, only the number of preoperative comorbidities and advanced age were independent predictors of survival (P < .0001), whereas ischemic mitral regurgitation, sex, ejection fraction, New York Heart Association class, coronary disease, reoperation, and year of operation did not achieve significance (all P > .19). After being adjusted for differences in all preoperative risk factors, survival was not statistically different between ischemic mitral regurgitation and nonischemic mitral regurgitation (P = .33). CONCLUSIONS: With routine application of rigid ring annuloplasty, long-term patient survival is more influenced by baseline patient characteristics and comorbidity than by ischemic cause of mitral regurgitation per se. Future risk assessment and decision making should be based on patient condition and should not be biased by ischemic cause of mitral regurgitation.     

Mitral valve surgery for chronic ischemic mitral regurgitation

BACKGROUND: Early and midterm clinical and echocardiographic results after mitral valve (MV) surgery for chronic ischemic mitral regurgitation were investigated to evaluate the validity of the criteria for repair or replacement applied by us. METHODS: From 1988 to 2002, 102 patients with ischemic mitral regurgitation underwent MV surgery (82 repairs and 20 replacements). End-systolic distance between the coaptation point of mitral leaflets and the plane of mitral annulus was the key factor that allowed either repair (10 mm). Patients who had MV replacement showed higher New York Heart Association class (3.2 +/- 0.5 versus 3.4 +/- 0.5; p = 0.016), lower preoperative ejection fraction (0.33 +/- 0.9 versus 0.38 +/- 0.12; p = 0.034), and higher end-diastolic volume (161 +/- 69 mL versus 109 +/- 35 mL; p < 0.001) compared with repair. Mitral regurgitation was 3.2 +/- 0.7 in both groups. RESULTS: Thirty-day mortality was 3.9% (2.4% MV repair versus 10.0% MV replacement; not significant). During the follow-up 26 patients died. Of the 72 survivors, 55 (76.3%) were in New York Heart Association classes I and II. Five-year survival was 75.6% +/- 4.7% in MV repair and 66.0% +/- 10.5% in MV replacement (not significant). Survival in New York Heart Association classes I and II was 58.9% +/- 5.4% in MV repair and 40.0% +/- 11.0% in MV replacement (not significant). Cox analysis identified preoperative New York Heart Association class, ejection fraction, end-diastolic volume, end-systolic volume, and congestive heart failure as risk factors common to both events. In 46 patients, late echocardiograms showed no volume or ejection fraction modifications. In patients who underwent MV repair, 50% had no or mild mitral regurgitation. CONCLUSIONS: Correction of chronic ischemic mitral regurgitation through either repair or replacement provides a good 5-year survival rate, with more than 75% of the survivors in New York Heart Association classes I and II.     

Midterm outcome of mitral valve repair for congenital mitral regurgitation in infants and children

We analyzed the midterm results of children undergoing mitral valve repair without the use of prosthetic materials focusing on mitral annulus growth. From 1991 to 2004, 17 children (median age: 11 months) underwent mitral valve repair (grade III=9, IV=8). Regurgitation was due to prolapsed leaflet in 8 patients, annular dilatation in 4, and restrictive leaflet motion in 5. Preoperative indexed mitral valve diameter and Z-value were compared with those obtained at follow-up. There were no early or late deaths. All patients had an improved regurgitation grade after surgery. MV repair resulted in reduction in the indexed mitral valve diameter (58.2+/-22.9 vs. 47.3+/-18.9 mm/m2, P<0.05) and Z-value (3.3+/-2.3 vs. 0.79+/-2.2, P<0.05). One patient underwent re-repair, but no patients required mitral valve replacement during the median follow-up period of 95 months. The latest regurgitation grade was absent or I in 4 patients, II in 10 patients, and III in 3 patients. Mitral valve annulus increased by 23% at 3 years and by 49% at 5 years compared with that at surgery. Mitral valve repair without the use of prosthetic materials is feasible for the majority of patients and carries an appropriate growth pattern of the mitral valve annulus after surgery.     

Determinants of survival after surgery for mitral valve regurgitation in patients with and without coronary artery disease

Mortality and its determinants were assessed in 181 consecutive patients undergoing primary mitral valve surgery for pure mitral regurgitation with coronary artery disease (MR + CAD, 79 patients) or without (MR no CAD, 102 patients). Early mortality (C10% vs. 3%) and 6-year estimate of survival (55% +/- 7.1% vs. 82% +/- 4.4%) were significantly different. Mortality was not significantly different in patients with CAD + MR of an ischemic (49 patients) or a non-ischemic etiology (30 patients). Multivariate testing using Cox regression models of overall mortality in patients with MR + CAD indicated that preoperative renal dysfunction, high right atrial pressure, ejection fraction less than 45% as well as qualitatively reduced left ventricular function and left ventricular end-diastolic volume index greater than 120 ml/m2 are associated with decreased survival. Multivariate testing in patients with MR no CAD only identified insertion of a mechanical prosthesis and a degenerative etiology of mitral valve disease as independent predictors of survival. Thus, a common denominator of preoperative pathology (renal dysfunction) and indices of right and left ventricular dysfunction determined overall survival of patients with MR + CAD. Survival of patients with MR no CAD was determined by the valve prosthesis and the etiology of valve disease.     

The effect of preoperative atrial fibrillation on survival following mitral valve repair for degenerative mitral regurgitation.

OBJECTIVE: There is conflicting evidence with regard to the impact of preoperative atrial fibrillation (AF) on the post mitral valve (MV) repair on the early and late outcome. METHODS: A total of 349 patients undergoing various MV repair procedures for degenerative mitral regurgitation (MR) between 1997 and 2003 were studied. Preoperatively, 152 (44%) of these patients were in AF and 197 (56%) patients were in sinus rhythm (SR). The clinical features and the outcome in these two cohorts of patients were compared. RESULTS: The patients in the AF group were older than their counterparts in the SR group (66+/-7 vs 62+/-9 years) (p=0.01), had a higher mean NYHA class score (2.4+/-0.6 vs 2.2+/-0.7) (p=0.04) and were more likely to have impaired left ventricular function (60% vs 36%) (p<0.0001). A similar proportion of patients in the AF (38%) and SR (30%) groups had additional cardiac surgical procedures (p=0.12). Operative mortality was 3.9% in AF group versus 0.5% in SR group (p=0.04), and operative morbidity was 27% versus 17%, respectively (p=0.03). At latest follow up, 4% of patients that were in SR preoperatively developed AF; conversely, 2% of the patients in the AF group converted to SR. The rates of recurrent grade II or III MR (4% vs 5%) (p=0.8) and MV re-operation (2.6% vs 2.5%) (p=1.0) were similar in the AF and SR groups. Kaplan-Meier survival at 7 years was 75+/-6% versus 90+/-3% (p=0.005). On Cox proportional hazards regression model, impaired LV function [(p=0.02), hazard ratio 0.25 (95% confidence intervals (C.I.) 0.078-0.84)] and AF [(p=0.03), hazard ratio 2.70 (95% C.I. 1.09-6.68)] were significant adverse predictors of survival. CONCLUSIONS: This study shows that in patients undergoing MV repair for degenerative MR, preoperative AF has a major negative impact on the early and late survival.     

Effects of acute ischemic mitral regurgitation on three-dimensional mitral leaflet edge geometry.

BACKGROUND: Improved quantitative understanding of in vivo leaflet geometry in ischemic mitral regurgitation (IMR) is needed to improve reparative techniques, yet few data are available due to current imaging limitations. Using marker technology we tested the hypotheses that IMR (1) occurs chiefly during early systole; (2) affects primarily the valve region contiguous with the myocardial ischemic insult; and (3) results in systolic leaflet edge restriction. METHODS: Eleven sheep had radiopaque markers sutured as five opposing pairs along the anterior (A(1)-E(1)) and posterior (A(2)-E(2)) mitral leaflet free edges from the anterior commissure (A(1)-A(2)) to the posterior commissure (E(1)-E(2)). Immediately postoperatively, biplane videofluoroscopy was used to obtain 4D marker coordinates before and during acute proximal left circumflex artery occlusion. Regional mitral orifice area (MOA) was calculated in the anterior (Ant-MOA), middle (Mid-MOA), and posterior (Post-MOA) mitral orifice segments during early systole (EarlyS), mid systole (MidS), and end systole (EndS). MOA was normalized to zero (minimum orifice opening) at baseline EndS. Tenting height was the distance of the midpoint of paired markers to the mitral annular plane at EndS. RESULTS: Acute ischemia increased echocardiographic MR grade (0.5+/-0.3 vs 2.3+/-0.7, p<0.01) and MOA in all regions at EarlyS, MidS, and EndS: Ant-MOA (7+/-10 vs 22+/-19 mm(2), 1+/-2 vs 18+/-16 mm(2), 0 vs 17+/-15 mm(2)); Mid-MOA (9+/-13 vs 25+/-17 mm(2), 3+/-6 vs 21+/-19 mm(2), 0 vs 25+/-17 mm(2)); and Post-MOA (8+/-10 vs 25+/-16, 2+/-4 vs 22+/-13 mm(2), 0 vs 23+/-13 mm(2)), all p<0.05. There was no change in MOA throughout systole (EarlyS vs MidS vs EndS) during baseline conditions or ischemia. Tenting height increased with ischemia near the central and the anterior commissure leaflet edges (B(1)-B(2): 7.1+/-1.8mm vs 7.9+/-1.7 mm, C(1)-C(2): 6.9+/-1.3mm vs 8.0+/-1.5mm, both p<0.05). CONCLUSIONS: MOA during ischemia was larger throughout systole, indicating that acute IMR in this setting is a holosystolic phenomenon. Despite discrete postero-lateral myocardial ischemia, Post-MOA was not disproportionately larger. Acute ovine IMR was associated with leaflet restriction near the central and the anterior commissure leaflet edges. This entire constellation of annular, valvular, and subvalvular ischemic alterations should be considered in the approach to mitral repair for IMR.     

Are there indications for reconstructive surgery in severe mitral regurgitation after acute myocardial infarction?

From 1972 to 1988, early surgery were performed in 26 patients with acute mitral regurgitation (MR) unresponsive to medical management complicating a recent acute myocardial infarction (AMI). The indication was acute pulmonary oedema (11), major left ventricular insufficiency (5), cardiogenic shock (10). Surgery was performed within 3 weeks following AMI. Mitral lesions were as follows: rupture of chordae tendinae (9) of papillary muscle (6), haemorrhagic necrosis of one (17) or two (9) papillary muscles. The mitral annulus was never found to be enlarged. The LV posterior wall was necrotic in 23, with a septal rupture in 3 and a giant aneurysm in 5. Valve replacement was performed in all but one patient. The 30-day mortality included 8 patients (31%). The cause of death was myocardial insufficiency in 5, early thrombosis of a disk valve in 1 and unrelated complications in 2. One patient deteriorated rapidly and had a Jarvik device implanted. Late results (1 month-15 years) showed 4 cardiac related deaths within the first year. One patient had to be transplanted after 1 year. Two patients died of non-cardiac problems at 3 months and 5 years. The probability of survival at 5 years is 43% and at 10 years 22%. In conclusion, there are still indications for early surgery in MR post AMI. Anatomical lesions of both papillary muscles and ventricular wall do not allow conservative surgery and new non-invasive technics provide a more promising strategy in such desperately ill patients.     

Selecting patients with mitral regurgitation and left ventricular dysfunction for isolated mitral valve surgery

Background

American College of Cardiology/American Heart Association (ACC/AHA) Guidelines state that patients with an ejection fraction (EF) of 30% or less should not undergo mitral valve replacement for mitral regurgitation (MR). We sought to establish, using a national cardiac surgery database, whether patients with left ventricular dysfunction may safely undergo mitral valve surgery for MR, and if so, which ones.

Methods

We queried the Society of Thoracic Surgeons (STS) National Database to identify patients who had isolated mitral valve replacement or repair for MR between 1998 and 2001. Mortality and morbidity outcomes were compared by EF category (≤ 30% vs > 30%), and observed mortality compared by EF group, stratified by predicted risk for mortality. A classification and regression tree (CART) model was then used to determine which patient characteristics contributed most to designate the high-risk patient.

Results

Of the 14,582 patients who had mitral valve surgery, 727 had an EF of 30% or less and 13,855 had an EF of more than 30%. Observed mortality rates were higher for patients with an EF of 30% or less (5.4% vs 3.1%). However, for low-risk to medium-risk patients, mortality rates remained fairly constant across levels of EF. Mortality is notably increased in the high-risk patients (predicted risk > 10%). A classification tree identifies three key characteristics for high risk: age more than 75 years, renal failure, and emergent or salvage procedure.

Conclusions

When the predicted mortality risk is less than 10%, EF has minimal impact on operative mortality for mitral regurgitation. In contrast to the ACC/AHA Guidelines, our data show that operative risk for mitral valve surgery is not prohibitive for most patients with ventricular dysfunction.     

Tricuspid regurgitation after successful mitral valve surgery

The tricuspid valve (TV) is inseparably connected with the mitral valve (MV) in terms of function. Any pathophysiological condition concerning the MV is potentially a threat for the normal function of the TV as well. One of the most challenging cases is functional tricuspid regurgitation (TR) after surgical MV correction. In the past, TR was considered to progressively revert with time after left-sided valve restoration. Nevertheless, more recent studies showed that TR could develop and evolve postoperatively over time, as well as being closely associated with a poorer prognosis in terms of morbidity and mortality. Pressure and volume overload are usually the underlying pathophysiological mechanisms; structural alterations, like tricuspid annulus dilatation, increased leaflet tethering and right ventricular remodelling are almost always present when regurgitation develops. The most important risk factors associated with a higher probability of late TR development involve the elderly, female gender, larger left atrial size, atrial fibrillation, right chamber dilatation, higher pulmonary artery systolic pressures, longer times from the onset of MV disease to surgery, history of rheumatic heart disease, ischaemic heart disease and prosthetic valve malfunction. The time of TR manifestation can be up to 10 years or more after an MV surgery. Echocardiography, including the novel 3D Echo techniques, is crucial in the early diagnosis and prognosis of future TV disease development. Appropriate surgical technique and timing still need to be clarified.     

Long-term clinical outcome of mitral valve repair in asymptomatic severe mitral regurgitation

Objective: To assess the long-term survival, the incidence of cardiac complications and the factors that predict outcome in asymptomatic patients with severe degenerative mitral regurgitation (MR) undergoing mitral valve repair. Methods: Up to 143 asymptomatic patients (mean age 63 ± 12 years) with severe degenerative MR who underwent mitral valve repair between 1990 and 2001 were subsequently followed up for a median of 8 years. The study population was subdivided into three subgroups: patients with left ventricular (LV) dysfunction and/or dilatation (n = 18), patients with atrial fibrillation and/or pulmonary hypertension (n = 44) and patients without MR-related complications (n = 81). Results: For the patients, 10-year overall and cardiovascular survival was 82 ± 4% and 90 ± 3%. At 10 years, patients without preoperative MR-related complications had significantly better overall survival than patients with preoperative LV dysfunction and/or dilatation (89 ± 4% vs 57 ± 13%, log rank p = 0.001). Patients without preoperative MR-related complications also tended to have a better 10-year overall and cardiovascular survival than patients with atrial fibrillation and/or pulmonary hypertension (overall survival of 79 ± 8%), although this did not reach statistical significance (log rank p = 0.17). Cox regression analysis identified the baseline left ventricular ejection fraction and age as the sole independent predictors of outcome. Conclusion: Our data indicate that in asymptomatic patients with severe degenerative MR, mitral valve repair is associated with an excellent long-term prognosis. Nonetheless, the presence of preoperative MR-related complications, in particular LV dysfunction and/or dilatation, greatly attenuates the benefits of surgery. This suggests that mitral valve repair should be performed early, before any MR-related complications ensue.     

Impact of preoperative and postoperative atrial fibrillation on outcome after mitral valvuloplasty for nonischemic mitral regurgitation

OBJECTIVE: We sought to determine the impact of preoperative or postoperative atrial fibrillation on survival, stroke, and cardiac function after mitral valvuloplasty for mitral regurgitation. METHODS: Between 1991 and 2003, 1026 patients with nonischemic/noncardiomyopathy mitral valve regurgitation underwent mitral valve plasty in 3 centers; 663 patients remained in sinus rhythm (group A), and 363 patients had atrial fibrillation or flutter preoperatively (group B) with concomitant maze procedures (group BM, n = 163) or without maze procedures (group BN, n = 200). RESULTS: Eight-year freedom from cardiovascular-related death was better in group A (99.3%) than group B (BM: 96.9%, BN: 81.6%) ( P < .001) and also better in group BM than group BN ( P = .007). The adjusted hazard ratio of group B versus group A for preoperative differences was 5.1 (95% confidence interval: 1.8-14.8). Eight-year freedom from stroke was better in group A (99.2%) than group B (BM: 98.2%, BN: 82.6%) ( P < .001) and also better in group BM than group BN ( P < .001). Patients with preoperative atrial fibrillation had larger left atria and left ventricular systolic dimensions. The adjunct maze procedure improved left ventricular systolic dimensions over mitral repair alone (group A vs B: P = .359; group BM vs BN: P = .001). CONCLUSION: Preoperative permanent/persistent atrial fibrillation was associated with a dilated left atrium and reduced left ventricular function in patients with mitral regurgitation. Including the maze procedure with mitral repair improved survival, late cardiac function, and freedom from late stroke.     

Results of mitral surgery in octogenarians with isolated nonrheumatic mitral regurgitation

Background

Increasing numbers of elderly patients are now referred for mitral valve operations. It has been unclear whether the results offset the risk of intervention in this patient population.

Methods

We obtained clinical follow-up through May 2002 of 59 patients 80 years or older who underwent first-time isolated mitral valve repair (46 patients) or replacement (13 patients) for nonischemic, nonrheumatic mitral regurgitation from January 1990 to June 2000. The mean duration of follow-up was 68 ± 33 months. Observed survival was compared with the expected survival of persons of the same age and gender in the general population.

Results

Preoperatively 79% of patients were in New York Heart Association (NYHA) class III-IV. Operative mortality was 1.7%. Overall 1- and 5-year survival was 89% and 61%. One- and 5-year freedom from thromboembolic complications in hospital survivors was 97% and 84%. One- and 5-year freedom from heart-related hospitalization in hospital survivors was 89% and 78%. There were no reoperations. Twenty-nine patients underwent an echocardiographic follow-up; 31% of them exhibited moderate or more regurgitation. Of 37 surviving patients at follow-up, 78% were in NYHA functional class I-II. No statistically significant difference was noted between the observed survival postoperatively and the expected survival of persons of the same age and gender in the general population. In a univariate analysis, only preoperative left ventricular ejection fraction greater than 40% was significantly associated with freedom from late heart-related mortality (95% confidence interval 62%-92%, p = 0.01) and with freedom from heart-related hospitalization (95% CI 68%-95%, p < 0.01).

Conclusions

Native mitral valve surgery for isolated nonischemic, nonrheumatic disease in octogenarians resulted in a survival rate comparable with that of the general population. It also exhibited substantial improvement regarding the functional status of the patient. Reparative techniques did not result in a survival advantage compared with replacement but did prove to be a reliable approach. Surgery performed in an early stage, preceding the development of left ventricular dysfunction, was associated with an improved freedom from late cardiac complications.