Usefulness of preoperative exercise tolerance to predict late survival and symptom persistence after surgery for chronic nonischemic mitral regurgitation.

Exercise duration during exercise treadmill testing (ETT) predicts long-term outcome among asymptomatic patients with mitral regurgitation. However, the prognostic value of preoperative exercise duration in patients who undergo mitral valve surgery is unknown. We examined findings among 45 prospectively followed (average 9.2 ± 4.3 years) patients (aged 54.8 ± 12.0 years, 45% men) with chronic isolated severe MR who underwent ETT before mitral valve surgery to test the hypotheses that exercise duration predicts long-term postoperative survival and persistent symptoms within 2 years after operation. During follow-up, 11 patients died; of these, 8 had persistent symptoms. Among patients who exercised >7 minutes, average annual postoperative all-cause and cardiovascular mortality risks were 0.75% (both endpoints) versus 5.4% and 4.8%, respectively, versus those who exercised ≤7 minutes (p = 0.003 all-cause, p = 0.007 cardiovascular). Exercise duration predicted postoperative deaths (p <.02 all cause, p <.04 cardiovascular) even when analysis was adjusted for preoperative variations in age, gender, medications, history of atrial fibrillation, and peak exercise heart rates. Other ETT, echocardiographic, and clinical variables were not independently associated with these outcomes when exercise duration was considered in the analysis. Preoperative exercise duration also predicted postoperative (New York Heart Association functional class ≥II) symptom persistence (p = 0.012), whereas other ETT, echocardiographic and clinical variables did not (NS, all). In conclusion, among patients who undergo surgery for chronic nonischemic mitral regurgitation, preoperative exercise duration, unlike many commonly used descriptors, is useful for predicting postoperative mortality and symptom persistence. Future research should determine whether interventions to improve exercise tolerance before mitral valve surgery can modify these postoperative outcomes.

Nonischemic mitral regurgitation: prognostic value of nonsustained ventricular tachycardia after mitral valve surgery.

BACKGROUND: Nonsustained ventricular tachycardia (VT), frequent in unoperated severe mitral regurgitation (MR), confers mortality risk [sudden death (SD) and cardiac death (CD)]. The prognostic value of VT after mitral valve surgery (MVS) is unknown; we aimed to define this prognostic value and to assess its modulation by left (LV) and/or right (RV) ventricular ejection fraction (EF) for mortality after MVS. METHODS: In 57 patients (53% females, aged 58 ± 12 years) with severe MR prospectively followed before and after MVS, we performed 24-hour ambulatory electrocardiograms approximately annually. LVEF and RVEF were determined within 1 year after MVS by radionuclide cineangiography. RESULTS: During 9.52 ± 3.49 endpoint-free follow-up years, late postoperative CD occurred in 11 patients (7 SD, 4 heart failures). In univariable analysis, >1 VT episode after MVS predicted SD (p < 0.01) and CD (SD or heart failure; p < 0.04). Subnormal postoperative RVEF predicted CD (p < 0.04). When adjusted for preoperative age, gender, etiology or antiarrhythmics, both postoperative VT and RVEF predicted CD (p ≤ 0.05). When postoperative VT and RVEF were both in the multivariable model, only subnormal RVEF predicted CD (p < 0.04). Among those with normal RVEF, VT >1 episode predicted SD (p = 0.03). CONCLUSION: Postoperative VT and subnormal RVEF predict late postoperative deaths in nonischemic MR. Their assessment may aid patient management.

Prognostic impact of systolic hypertension on asymptomatic patients with chronic severe aortic regurgitation and initially normal left ventricular performance at rest.

The influence of systolic hypertension (SH) on the natural history of chronic aortic regurgitation (AR) and the clinical effect of antihypertensive medication on patients who have hypertension and AR are incompletely defined. Therefore, we reviewed the clinical course of 80 unoperated patients who were entered prospectively into an assessment of natural history of AR and its predictors and were asymptomatic with normal left ventricular ejection fraction (LVEF) at rest at study entry; 30 of 80 patients had SH (systolic blood pressure >140 mm Hg); 20 of 80 patients (16 had SH) used antihypertensive drugs for the long term (not mandated by protocol). During an average 7.2-year event-free follow-up, 24 patients developed symptoms alone (n = 14), subnormal LVEF with or without symptoms (n = 8), or died suddenly (n = 2). SH tripled the average annual risk of cardiac events (8.47% vs 2.85%, p = 0.004). The effect of systolic blood pressure was independent of age, gender, diastolic blood pressure, LV diastolic dimension, fractional shortening, and LVEF at rest (p = 0.004 to <0.008). However, positive prognostic interactions existed between systolic blood pressure and pulse pressure (p <0.001), LVEF during exercise (p <0.001), change in LVEF from rest to exercise (p <0.001), and the contractility index (p <0.02). Among patients who had SH, antihypertensive therapy predicted increased event risk (average annual risk 15.46% vs 3.98%, p <0.02) and remained predictive when analysis was adjusted for potentially confounding subgroup variations at study entry (p <0.03, all models). In conclusion, SH portends poor clinical outcome in chronic severe AR. As a group, antihypertensive drugs do not mitigate outcome, although the effect of individual drugs is uncertain and at least some may be deleterious. The theoretically based practice of giving antihypertensive drugs to patients who have AR requires reexamination.