Revascularization of hibernating myocardium: rate of metabolic and functional recovery and occurrence of oxidative stress.

BACKGROUND: Left ventricular (LV) dysfunction due to coronary artery disease (CAD) may improve after revascularization in patients with hibernating myocardium (HM). METHODS AND RESULTS: We compared the rate of metabolic (arterial-great cardiac vein differences of lactate, glucose and pyruvate) and functional (intra-operative transesophageal and epicardial echocardiography) recovery and occurrence of oxidative stress (myocardial release of oxidized glutathione (GSSG)) early after surgical revascularization, in patients with CAD, LV dysfunction and HM (n=16) vs those with preserved LV function (n=15). By comparing the two groups, we observed that, after de-clamping, in patients with HM (a) the kinetic of lactate production was converted to extraction (P<0.01 at 1, 5, 10 and 20 min after revascularization), (b) myocardial extraction of pyruvate increased (P<0.01 during the first 5 min after revascularization), (c) GSSG release was less and of shorter duration (P<0.01 at all times), (d) segmental wall motion score improved from 2.4+/-0.3 to 1.7+/-0.5 (P<0.01) as did the thickening of the akinetic territories corresponding to the antero-distal septum and to the distal anterior wall regions (to 36+/-23%, and to 36+/-13%, respectively). There was a correlation between the rate of recovery of metabolic and functional indices. CONCLUSIONS: The contractile and metabolic recovery of HM is more rapid than that of non-HM, and it is not accompanied by oxidative stress.

Outcomes 15 years after valve replacement with a mechanical versus a bioprosthetic valve: final report of the Veterans Affairs randomized trial.

OBJECTIVES: The goal of this study was to compare long-term survival and valve-related complications between bioprosthetic and mechanical heart valves. BACKGROUND: Different heart valves may have different patient outcomes. METHODS: Five hundred seventy-five patients undergoing single aortic valve replacement (AVR) or mitral valve replacement (MVR) at 13 VA medical centers were randomized to receive a bioprosthetic or mechanical valve. RESULTS: By survival analysis at 15 years, all-cause mortality after AVR was lower with the mechanical valve versus bioprosthesis (66% vs. 79%, p = 0.02) but not after MVR. Primary valve failure occurred mainly in patients <65 years of age (bioprosthesis vs. mechanical, 26% vs. 0%, p < 0.001 for AVR and 44% vs. 4%, p = 0.0001 for MVR), and in patients > or =65 years after AVR, primary valve failure in bioprosthesis versus mechanical valve was 9 +/- 6% versus 0%, p = 0.16. Reoperation was significantly higher for bioprosthetic AVR (p = 0.004). Bleeding occurred more frequently in patients with mechanical valve. There were no statistically significant differences for other complications, including thromboembolism and all valve-related complications between the two randomized groups. CONCLUSIONS: At 15 years, patients undergoing AVR had a better survival with a mechanical valve than with a bioprosthetic valve, largely because primary valve failure was virtually absent with mechanical valve. Primary valve failure was greater with bioprosthesis, both for AVR and MVR, and occurred at a much higher rate in those aged <65 years; in those aged > or =65 years, primary valve failure after AVR was not significantly different between bioprosthesis and mechanical valve. Reoperation was more common for AVR with bioprosthesis. Thromboembolism rates were similar in the two valve prostheses, but bleeding was more common with a mechanical valve.

Sensitivity, specificity, and predictive accuracies of non-invasive tests, singly and in combination, for diagnosis of hibernating myocardium.

OBJECTIVE: To determine the best test(s) for predicting functional recovery of hibernating myocardium after reperfusion. METHODS: A prospective study to compare echocardiographic left ventricular diastolic wall thickness (> or =5 mm), low-dose dobutamine echocardiography and rest-redistribution thallium-201 scintigraphy, alone and in combination, for predicting recovery of left ventricular akinesis after surgical revascularization. RESULTS: Twenty-eight consecutive patients aged 58+/-9 years were studied. Of the 448 left ventricular segments, 263 were akinetic at rest; 230/263 (87%) had wall thickness > or =5 mm, 135 (51%) had a positive response and 175 (66.5%) were graded viable on thallium. Of akinetic segments 61% improved after surgery. Left ventricular score decreased from 2.3+/-0.4 to 1.8+/-0.4 (P<0.01) and ejection fraction increased from 27+/-10 to 37+/-14% (P<0.01). For predicting results at 1 year, diastolic wall thickness had a sensitivity and a predictive accuracy of a negative test of 100% but a specificity of 28% and predictive accuracy of a positive test of 61%. The addition of dobutamine echocardiography or thallium-201 improved the predictive accuracy of a positive test to 76% and 69%, respectively; the addition of both tests was not of greater benefit than that of a single test. CONCLUSIONS: Diastolic wall thickness <5 mm on echocardiography was the best simple and single predictor of non-recovery of left ventricular dysfunction. The addition of dobutamine echocardiography or thallium-201, but not both, was the best solution for predicting recovery of left ventricular dysfunction. In times of limited resources, these findings are important from a clinical point of view.

Concept and evaluation of hibernating myocardium.

Hibernating myocardium is a state of persistently impaired myocardial and left ventricular function at rest due to reduced coronary blood flows. It can be defined as an exquisitely regulated tissue successfully adapting its activity to prevailing circumstances. It has been documented in patients with angina (chronic stable and/or unstable), acute myocardial infarction, heart failure and/or severe left ventricular dysfunction, and anomalous left coronary artery from the pulmonary artery. The diagnosis of hibernating myocardium involves (a) documenting left ventricular dysfunction at rest and (b) documenting that there is viable myocardium in the area of dysfunction. Tests commonly used for the latter are dobutamine echocardiography, 201Tl isotope studies, and positron image tomography. Revascularization, either by surgery or by interventional catheter techniques, has been shown to improve or normalize the abnormal left ventricular function at rest.

Actuarial outcome after catheter balloon commissurotomy in patients with mitral stenosis.

BACKGROUND: The goal of the present study was to determine the intermediate-term survival and the independent predictors of survival and event-free survival for patients who undergo catheter balloon commissurotomy (CBC). METHODS AND RESULTS: CBC for the treatment of mitral stenosis was performed in 132 patients from 1986 through 1994. The use of CBC increased the mitral valve area (MVA) from 1.0 +/- 0.3 to 1.9 +/- 0.6 cm2 (P < .001). There were six early deaths (4.5%) up to 1 month after CBC ("hospital" deaths). In the past 4.5 years, there have been no hospital deaths. Four late deaths occurred after elective mitral valve replacement (MVR). Actuarial 7-year survival was 95 +/- 1%; when mortality after MVR is included, 7-year survival was 83 +/- 6%. Actuarial 1-, 3-, 5-, and 7-year event-free survival (survival without MVR or repeat CBC) was 80 +/- 4%, 77 +/- 4%, 65 +/- 6%, and 65 +/- 6%. On multivariate analysis, the only two independent predictors (both after CBC) of 7-year event-free survival were MVA of > or = 1.5 versus < 1.5 cm2 (75 +/- 7% versus 32 +/- 12%) and mean pulmonary artery wedge pressure of < or = 18 versus > 18 mm Hg (84 +/- 6% versus 38 +/- 11%) (P < .001 for both). Patients with MVA of > or = 1.5 cm2 (n = 96) could be further subdivided into high- and low-risk subgroups for 7-year event-free survival by two post-CBC variables: mean pulmonary artery wedge pressure of < or = 18 versus > 18 mm Hg (90 +/- 6% versus 48 +/- 14%) (P = .0002) and cardiac index of > or = 2.5 versus < 2.5 L.min-1.m-2 (82 +/- 8% versus 61 +/- 13%) (P = .004). Patients with post-CBC MVA of < 1.5 cm2 (n = 24) had no additional predictors of event-free survival. Of patients who did not undergo MVR or repeat CBC, 8% were in New York Heart Association functional class III and 92% were in class I or early class II at the last follow-up. CONCLUSIONS: The rates for intermediate-term survival and event-free survival after CBC are very encouraging. Most patients without events were asymptomatic or minimally symptomatic. Thus, in selected patients with mitral stenosis who require an interventional procedure, CBC is the procedure of choice at centers with physicians who have experience and skill in performing this procedure.