J. Scott Rankin

Trends in Mitral Valve Surgery in the United States: Results From The Society of Thoracic Surgeons Adult Cardiac Database

BACKGROUND The purpose of this study is to examine trends in mitral valve (MV) repair and replacement surgery using The Society of Thoracic Surgeons Adult Cardiac Surgery Database (STS ACSD). METHODS The study population included isolated mitral valve operations performed between January 2000 and December 2007 at 910 hospitals participating in the STS ACSD. Patients with endocarditis, prior cardiac operation, shock, emergency operation, and concomitant coronary artery bypass graft or aortic valve surgery were excluded. RESULTS During the 8-year study period, 58,370 patients underwent isolated primary MV operations. For patients with isolated mitral regurgitation (n = 47,126), the rate of MV repair (versus replacement) increased from 51% to 69% (p < 0.0001). Among patients having replacement (n = 24,404), there has been a pronounced decline in the use of mechanical valves: 68% to 37% (p < 0.0001). The operative mortality for MV replacement was consistently higher than that for repair (3.8% versus 1.4%), a finding that persisted after risk-adjustment (adjusted odds ratio 0.52, 95% confidence interval: 0.45 to 0.59; p < 0.0001). Among patients having elective isolated MV repair (n = 28,140), the operative mortality was 1.2%. For asymptomatic (class I) patients, operative mortality was 0.6%. CONCLUSIONS This study documents several important trends in MV surgery, including the progressive adoption of mitral valve repair and increasing use of bioprosthetic replacement valves. Operative risks of MV repair are significantly lower than those for MV replacement. Operative mortality for isolated elective mitral valve repair is 1% in contemporary clinical practice.

Outcome of patients sustaining acute ischemic mitral regurgitation during myocardial infarction.

OBJECTIVE To describe outcomes of patients sustaining an acute myocardial infarction complicated by mitral regurgitation managed with contemporary reperfusion therapies. DESIGN Inception cohort case study. Long-term follow-up was obtained in 99% of all patients. SETTING University referral center. PATIENTS A series of 1,480 consecutive patients presenting between April 1986 and March 1989 who had emergency cardiac catheterization within 6 hours of infarction. Fifty patients were found to have moderately severe or severe mitral regurgitation. OUTCOME MEASURES Mortality; follow-up cardiac catheterization in patients with regurgitation. RESULTS Acute ischemic moderately severe to severe (3+ or 4+) mitral regurgitation was associated with a mortality of 24% at 30 days (95% CI, 12% to 36%), 42% at 6 months (CI, 28% to 56%), and 52% at 1 year (CI, 38% to 66%); multivariable analysis identified 3+ or 4+ mitral regurgitation as a possible independent predictor of mortality (P = 0.06). Patients with mitral regurgitation tended to be female, older, and to have cerebrovascular disease, diabetes, and preexisting symptomatic coronary artery disease. A physical examination did not identify 50% of patients with moderately severe to severe regurgitation. Acute reperfusion with thrombolysis or angioplasty did not reliably reverse valvular incompetence. In this observational study, the greatest in-hospital and 1-year mortalities were seen in patients reperfused with emergency balloon angioplasty, whereas patients managed medically or with coronary bypass surgery had lower mortalities. CONCLUSIONS Moderately severe to severe (3+ or 4+) mitral regurgitation complicating acute myocardial infarction portends a grave prognosis. Acute reperfusion does not reduce mortality to levels experienced by patients with lesser degrees of mitral regurgitation nor does it reliably restore valvular competence.

Less-Invasive Mitral Valve Operations: Trends and Outcomes From The Society of Thoracic Surgeons Adult Cardiac Surgery Database

BACKGROUND The purpose of this study was to examine utilization and outcomes of less-invasive mitral valve (LIMV) operations in North America. METHODS Between 2004 and 2008, 28,143 patients undergoing isolated mitral valve (MV) operations were identified in The Society of Thoracic Surgeons Adult Cardiac Surgical Database (STS ACSD). The LIMV operations were defined as those performed with femoral arterial and venous cannulation. RESULTS The LIMV operations increased from 11.9% of MV operations in 2004 to 20.1% in 2008 (p < 0.0001). In 2008, 26% of STS ACSD centers performed at least one LIMV operation, with a median of 3 per year. Patients in the LIMV group were younger and had fewer comorbidities. Median perfusion (135 versus 108 minutes) and cross-clamp times (100 versus 80 minutes, p < 0.0001) were longer in the LIMV group. Mitral valve repair rates were higher in the LIMV group (85% versus 67%, p < 0.0001). Adjusted operative mortality was similar (odds ratio 1.13, 95% confidence interval: 0.84 to 1.51, p = 0.47). Blood transfusion was less common (odds ratio 0.86, 95% confidence interval: 0.76 to 0.97, p < 0.0001) while stroke was more common (OR 1.96, 95% confidence interval: 1.46 to 2.63, p < 0.0001) in the LIMV group. CONCLUSIONS In selected patients, LIMV operations can be performed with equivalent operative mortality, shorter hospital stay, fewer blood transfusions, and higher rates of MV repair than conventional sternotomy. However, perfusion and cross-clamp times were longer, and the risk of stroke was significantly higher. Beating- or fibrillating-heart LIMV techniques are associated with particularly high risks for perioperative stroke.

The utility of transesophageal echocardiography and Doppler color flow imaging in patients undergoing cardiac valve surgery

To assess the value of intraoperative transesophageal echocardiography during cardiac valve surgery, 154 consecutive patients who had a valve operation in conjunction with pre- and postcardiopulmonary bypass transesophageal imaging were studied. Prebypass imaging yielded unsuspected findings that either assisted or changed the planned operation in 29 (19%) of the 154 patients. Imaging immediately after bypass revealed unsatisfactory operative results that necessitated immediate further surgery in 10 (6%) of the 154 patients. Postbypass left ventricular dysfunction, prompting administration of inotropic agents, was identified in 13 patients (8%). Transesophageal echocardiography proved most useful when both two-dimensional and Doppler color flow imaging were employed in patients undergoing a mitral valve operation, where surgical decisions based on echocardiographic results were made in 26 (41%) of 64 cases. Postbypass echocardiographic findings identified patients at risk for an adverse postoperative outcome. Of 123 patients whose postbypass valve function was judged to be satisfactory, 18 (15%) had a major postoperative complication and 6 (5%) died, whereas of 7 patients with moderate residual valve dysfunction, 6 (86%) had a postoperative complication and 3 (43%) died (p less than 0.05 for both). Likewise, of 131 patients with preserved postbypass left ventricular function, 12 (9%) had a major complication and 7 (5%) died, whereas of 23 patients with reduced ventricular function, 17 (73%) had a postoperative complication and 6 (26%) died (p less than 0.05 for both). These data indicate that intraoperative transesophageal echocardiography is useful in formulating the surgical plan, assessing immediate operative results and identifying patients with unsatisfactory results who are at increased risk for postoperative complications.

Survival Prognosis and Surgical Management of Ischemic Mitral Regurgitation

BACKGROUND Ischemic mitral regurgitation (IMR) has an adverse prognosis, but survival characteristics and management are controversial. This study reviewed a 20-year series of IMR patients managed with multiple approaches to assess and refine surgical strategies. METHODS Patients having surgery for primary coronary disease from 1986 to 2006 were divided into group 1 (no IMR; bypass grafting only; n = 16,209), group 2a (IMR; bypass only; n = 3,181), group 2b (IMR; mitral repair; n = 416), and group 2c (IMR; mitral replacement; n = 106). Cox proportional hazards modeling adjusted for baseline differences, and therapeutic adequacy was quantified by area under each survival curve expressed as a percentage of group 1. RESULTS Group 2 patients were older than group 1 patients and had worse baseline characteristics. Group 2a had less severe MR and group 2b had the most comorbidity. Assuming group 1 provided the best adjusted outcome at a given baseline risk, group 2a achieved 97.7%, 2b achieved 93.7%, and 2c achieved 79.1% of potential survival (hazard ratio 1.1, 1.4, and 1.6, respectively; p < 0.003). Most of the survival difference was perioperative. CONCLUSIONS Worse baseline risk is a major factor reducing long-term survival in IMR. Current algorithms in which mild to moderate IMR is managed with bypass only (group 2a) generally produced good late results. In patients with moderate and severe IMR, repair achieved 93.7% of full survival potential; valve replacement was less satisfactory, primarily owing to higher operative mortality. Future therapeutic refinement, emphasizing reparative procedures and better perioperative care, could enhance the surgical prognosis of IMR.

Fifteen-Year Outcome Trends for Valve Surgery in North America

BACKGROUND Although results in valvular heart surgery may be improving, too few cases are available in most centers to quantify changes, especially for uncommon procedural categories. This study examined comprehensively national trends in valve surgery outcomes over the past 15 years. METHODS From 1993 through 2007, 623,039 valve procedures were grouped into single aortic (A), mitral (M), and tricuspid (T) operations, along with AM, MT, AT, and AMT multiple valves ± coronary artery bypass graft surgery. Pulmonary valve surgery was excluded. Trends in baseline characteristics were documented, and logistic regression adjusted for differences in patient profiles. Outcomes were expressed as unadjusted operative mortality, adjusted odds ratios for mortality, and a composite of mortality and major complications. RESULTS Single valves comprised 89% of valve surgery and multiple valves, 11%. Preoperative patient risk profiles worsened over time. Mortality rates were higher for multiple valves, but all mortality rates fell significantly over the 15 years (p <0.001). The composite of mortality and major morbidity did not improve, however, largely because of increasing pulmonary/infectious complications. Overall, cardiac etiology accounted for 54% of deaths, and pulmonary/infectious etiologies for 16%. Cardiac etiology of death fell by 16% over time, but pulmonary death and complications increased by 78% and 39%, respectively. CONCLUSIONS Preoperative patient profiles for cardiac valve procedures have worsened over time. Risk-adjusted mortalities have fallen for all valve surgery, but remain higher for multiple valves. The finding of increasing pulmonary deaths and complications suggests that prevention and improved management of pulmonary and infectious complications could be an important focus for quality improvement.

Single Versus Multiple Internal Mammary Artery Grafting for Coronary Artery Bypass 15-Year Follow-Up of a Clinical Practice Trial

Background—The long-term clinical advantages of using routine multiple internal mammary artery (IMA) grafts for coronary artery bypass (CAB) are not clear. This study was designed to test the hypothesis that multiple IMA grafts would provide better 15-year outcomes when compared with single IMA and vein grafts. Methods and Results—Between 1984 and 1987, 1067 consecutive patients undergoing isolated CAB were referred to 1 surgeon practicing primarily single and another surgeon maximizing multiple IMA grafts (clinical practice trial). A 207-patient subset with multiple IMAs underwent postoperative graft angiography at 1 to 32 weeks to define initial IMA patency. Patients were followed-up yearly, and the groups were analyzed as (I) surgical strategy (surgeon operating) (single=413 versus multiple=654), (II) ultimate operation performed (single=418 versus multiple=449), or (III) single versus multiple coronary systems revascularized with IMAs (single=490 versus multiple=377). Advantages of this study design were that an entire referral population was examined, multiple IMAs were applied to the entire spectrum of baseline patient risk, 15-year follow-up provided a complete prognostic picture, and the subgroups were potentially comparable at baseline. In all 3 analyses, single and multiple groups were statistically similar with respect to baseline, operative, and immediate postoperative variables. Early IMA patency was 98.5% (333/338 grafts patent), validating the quality of IMA procedures. Unadjusted and adjusted 15-year outcome analyses for I, II, and III for death, myocardial infarction, percutaneous coronary intervention, redo coronary bypass, and the composite of all events identified multiple versus single as a significant predictor of outcome for the composite end point in adjusted analysis III (hazard ratio=0.808; 95% CI, 0.689 to 0.948; P=0.009), because of a 5% to 10% absolute reduction in each of the outcome variables at 15 years. Moreover, >50% reduction in reoperation rate was observed at 15 years in every analysis. Conclusions—At 15-year follow-up, multiple IMA grafting was associated with a 19.2% adjusted risk reduction in death and cardiac events, caused by decreases in all adverse end points and fewer reoperations. These data indicate that the clinical advantages of maximizing IMA conduits are significant. Based on this information, it is suggested that multiple IMA grafting to 2 coronary systems should be applied liberally to patients with noncardiac risk profiles predictive of long-term survival.

Trends and Outcomes of Tricuspid Valve Surgery in North America: An Analysis of More Than 50,000 Patients From The Society of Thoracic Surgeons Database

BACKGROUND This study evaluated trends and outcomes of tricuspid valve surgery (TVS) in North America over the past decade. METHODS Adults undergoing TVS between 2000 and 2010 were identified in The Society of Thoracic Surgeons (STS) National Database. Trends were evaluated using linear regression. Multivariable logistic regression analysis was conducted using covariates from the STS valve risk model to identify significant predictors of operative mortality. RESULTS A total of 54,375 patients underwent TVS during the study period. The majority of cases were repairs (89%; n = 48,322) and were performed concomitant with another major procedure (86%; n = 46,593). The proportion of TVS that were repairs increased from 84.6% in 2000 to 89.8% in 2010 (p = 0.01). Trend analysis revealed significant changes in patient characteristics with time, including increasing age, a higher comorbidity burden, and a higher proportion of emergency cases. Despite worsening risk factors, unadjusted operative mortality for TVS declined from 10.6% in 2000 to 8.2% in 2010 (p < 0.001), and this trend persisted after risk adjustment. In the multivariable model, concomitant procedures involving multiple valves or coronary artery bypass grafting were associated with an increased risk of mortality compared with isolated TVS, although other factors including renal failure, congestive heart failure, nonelective presentation, reoperation, and tricuspid valve replacement exerted equal or stronger effects. CONCLUSIONS During the past decade, repair rates for TVS have increased significantly. Although patients undergoing TVS have demonstrated worsening risk factors, unadjusted and adjusted operative mortalities have declined. Finally, the data suggest that tricuspid valve repair when technically feasible, together with early elective surgical intervention, should be emphasized as potential candidates for continued outcome improvement.

Comparison of preload recruitable stroke work, end-systolic pressure-volume and dPdtmax-end-diastolic volume relations as indexes of left ventricular contractile performance in patients undergoing routine cardiac catheterization☆

The end-systolic pressure-volume relation, the relation between stroke work and end-diastolic volume, termed the preload recruitable stroke work relation, and the relation between the peak of the first derivative of left ventricular pressure (dP/dtmax) and end-diastolic volume have been employed as linear indexes of left ventricular contractile performance in laboratory animals. The purpose of this study was to examine the relative utility of these indexes during routine cardiac catheterization in seven human subjects (mean age 48 +/- 18 [SD] years) with a normal left ventriculogram and coronary angiogram. Left ventricular pressure was recorded continuously with a micromanometer catheter, and left ventricular volume was derived from digital subtraction contrast ventriculograms obtained at 30-ms intervals. Transient occlusion of the inferior vena cava with a balloon-tipped catheter was employed to obtain beat to beat reductions in left ventricular pressure and volume over 8.7 +/- 1.7 cardiac cycles. Stroke work declined by 49 +/- 13% during vena caval occlusion, but end-systolic pressure fell by only 26 +/- 11%, and changes in dP/dtmax were small and inconsistent (12 +/- 22%). Consequently, the range of data available for determination of the preload recruitable stroke work relation greatly exceeded that for the end-systolic pressure-volume relation and the dP/dtmax-end-diastolic volume relation, and much less linear extrapolation from the measured data was required to determine the volume-axis intercept. Preload recruitable stroke work relations were highly linear (r = 0.95 +/- 0.07), and much more so than end-systolic pressure-volume relations (r = 0.79 +/- 0.23).(ABSTRACT TRUNCATED AT 250 WORDS)

Mitral Valve Repair for Degenerative Disease: A 20-Year Experience

BACKGROUND Recent advances in surgical technique allow repair of most mitral valves with degenerative disease. However, few long-term data exist to support the superiority of repair versus prosthetic valve replacement, and repair could be limited by late durability or other problems. This study was designed to compare survival characteristics of mitral valve repair versus prosthetic replacement for degenerative disorders during a 20-year period. METHODS From 1986 to 2006, 2,580 patients underwent isolated mitral valve procedures (with or without coronary artery bypass grafting), with 989 classified as having degenerative origin. Of these, 705 received valve repair, and 284 had prosthetic valve replacement. Differences in baseline characteristics between groups were assessed, and unadjusted survival estimates were generated using Kaplan-Meier methods. Survival curves were examined after adjustment for differences in baseline profiles using a Cox model, and average adjusted survival differences were quantified by area under the curve methodology. Survival differences during 15 years of follow-up also were assessed with propensity matching. RESULTS Baseline characteristics were similar, except for (variable: repair, replacement) age: 62 years, 68 years; concomitant coronary artery bypass grafting: 24%, 32%; ejection fraction: 0.51, 0.55; congestive heart failure: 68%, 43%; and preoperative arrhythmia: 11%, 7% (all p < 0.05). Long-term survival was significantly better in the repair group, both for unadjusted data (p < 0.001) and for risk-adjusted results (p = 0.040). Patient survival in the course of 15 years averaged 7.3% better with repair, and increased with time of follow-up: 0.7% better for 0 to 5 years, 4.9% better for 5 to 10 years, and 21.3% better for 10 to 15 years. Treatment interaction between repair or replacement and age was negative (p = 0.66). In the propensity analysis, survival advantages of repair versus replacement were similar in magnitude with a p value of 0.046. CONCLUSIONS As compared with prosthetic valve replacement, mitral repair is associated with better survival in patients with degenerative disease, especially after 10 to 15 years. This finding supports the current trend of increasing repair rates for degenerative disorders of the mitral valve.