Surgical Indication vs. Outcome Among Patients Operated for Organic Mitral Regurgitation

Study Questions:

Does the guideline Class of indication (early/prophylactic [IIa] vs. later [Class I]) for intervention correlate with outcome after surgery for organic mitral regurgitation (MR)?

Methods:

Between 1990 and 2000, 1,512 patients (age 64 ± 14 years, mitral prolapse in 89%, valve repair in 88%) underwent surgical correction for isolated organic MR. Patients were stratified according to surgical indication into Class I triggers (Class I: heart failure, ejection fraction <60%, end-systolic diameter ≥40 mm, n = 794), Class II triggers based on clinical complications (Class II-Comp: atrial fibrillation or pulmonary hypertension, n = 195), or early Class II triggers based on a combination of severe MR and high probability of valve repair (Class II-Early: n = 523).

Results:

Operative mortality was highest with Class I (1.1% vs. 0% and 0%, p = 0.016). Long-term survival was lower with Class I (15-year survival 42 ± 2%, adjusted hazard ratio [HR], 1.89; 95% confidence interval [CI], 1.53-2.34; p < 0.0001) and Class II-Comp (15-year survival 53 ± 4%, adjusted HR, 1.39; 95% CI, 1.04-1.84; p = 0.03) vs. Class II-Early (15-year survival 70 ± 3%, p < 0.0001). Postoperative excess mortality with Class I and Class II-Comp was confirmed by age stratification, inverse probability weighting, and expected survival adjustment. Excess postoperative heart failure was high with Class I (adjusted HR, 2.49; 95% CI, 1.82-3.47; p < 0.0001) and Class II-Comp (adjusted HR, 1.98; 95% CI, 1.30-3.00; p = 0.002).

Conclusions:

Despite low operative risk and high repair rates, the type of guideline-based indication for surgical correction of organic MR was associated with outcome consequences in terms of long-term postoperative mortality and heart failure. Conversely, surgical correction of severe MR based on high probability of repair (Class II-Early) was associated with improved survival and lower heart failure risk, and should be the preferred strategy in valve centers offering low operative risk and high repair rates.

Perspective:

Both 2014 American Heart Association/American College of Cardiology and 2012 European Society of Cardiology guidelines rely on the presence of symptoms or left ventricular (LV) systolic dysfunction (ejection fraction ≤60% or LV internal dimension in systole ≥40 mm) for Class I indications for intervention for severe primary MR. Early (prophylactic) surgery is a Class IIa or IIb indication, and relies on the assumption that surgical correction can be performed reliably, durably, at low risk, and with mitral valve repair rather than replacement. Data from this single-center study suggest that, when performed in a high-volume center with highly experienced surgeons, patient outcomes in terms of late mortality and freedom from heart failure are superior among patients operated earlier rather than later; and further a rationale of referral of asymptomatic patients with severe primary MR to a Heart Valve Center of Excellence.

Clinical Topics: Arrhythmias and Clinical EP, Cardiac Surgery, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Pulmonary Hypertension and Venous Thromboembolism, Valvular Heart Disease, Atrial Fibrillation/Supraventricular Arrhythmias, Cardiac Surgery and Arrhythmias, Cardiac Surgery and Heart Failure, Cardiac Surgery and VHD, Acute Heart Failure, Pulmonary Hypertension, Interventions and Structural Heart Disease, Mitral Regurgitation

Keywords: Atrial Fibrillation, Cardiac Surgical Procedures, Heart Failure, Heart Valve Diseases, Hypertension, Pulmonary, Mitral Valve Annuloplasty, Mitral Valve Insufficiency, Mitral Valve Prolapse, Survival


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