Myocardial Viability Testing Research Articles

Myocardial viability testing and impact of revascularization on prognosis in patients with coronary artery disease and left ventricular dysfunction: a meta-analysis

ObjectivesThis study pools data from published series examining late survival with revascularization versus medical therapy after myocardial viability testing in patients with severe coronary artery disease (CAD) and left ventricular (LV) dysfunction. BackgroundPrevious observational studies have suggested survival benefit in such patients if they are revascularized when myocardial viability is detected on imaging tests. MethodsA MEDLINE database search returned 24 viability studies reporting patient survival using thallium perfusion imaging, F-18 fluorodeoxyglucose metabolic imaging or dobutamine echocardiography. Annual death rates were extracted, pooled and analyzed with a random effects model. The risk-adjusted relationship between severity of LV dysfunction, presence of viability and survival benefit associated with revascularization was assessed by meta-regression. ResultsThere were 3,088 patients (2,228 men), ejection fraction 32 ± 8%, followed for 25 ± 10 months. In patients with viability, revascularization was associated with 79.6% reduction in annual mortality (16% vs. 3.2%, chi-square = 147, p < 0.0001) compared with medical treatment. Patients without viability had intermediate mortality, trending to higher rates with revascularization versus medical therapy (7.7% vs. 6.2%, p = NS). Patients with viability showed a direct relationship between severity of LV dysfunction and magnitude of benefit with revascularization (p < 0.001). There was no measurable performance difference for predicting revascularization benefit between the three testing techniques. ConclusionsThis meta-analysis demonstrates a strong association between myocardial viability on noninvasive testing and improved survival after revascularization in patients with chronic CAD and LV dysfunction. Absence of viability was associated with no significant difference in outcomes, irrespective of treatment strategy.

Positron emission tomography and low-dose dobutamine echocardiography in the prediction of postrevascularization improvement in left ventricular function and exercise parameters

Background We studied the value of low-dose dobutamine echocardiography (LDDE) and positron emission tomography (PET) in predicting improvement of left ventricular function and exercise parameters after revascularization. Methods Forty-six consecutive patients with ischemic heart disease and an ejection fraction (EF) of 35% ± 7% were included. Before revascularization, the patients underwent exercise testing and myocardial viability testing by LDDE and fluoride 18–fluoro-2-deoxyglucose PET. Six months after revascularization they underwent coronary angiography to study graft patency, and echocardiographic examination and the exercise test were repeated. Results In the prediction of the presence or absence of improved postrevascularization function in left ventricular regions with patent grafts, PET was more sensitive than LDDE (42/52 regions [81%] vs 27/52 regions [51%], P <.01), whereas LDDE was more specific than PET (187/209 regions [89%] vs 118/209 regions [56%], P <.001). Improvement of regional myocardial dysfunction was found in 19 patients, but their global left ventricular function did not improve significantly (EF 34% ± 6% and 36% ± 7%). In the remaining 27 patients with irreversible dysfunction, EF decreased (EF 36% ± 7% vs 32% ± 8%, P <.05). Among patients with reversible myocardial dysfunction, the rate pressure product (RPP) increased after revascularization (19,522 ± 5474 vs 26,190 ± 5610 mm Hg/min, P <.01), whereas the RPP did not change in patients with irreversible myocardial dysfunction (21,546 ± 5450 and 22,774 ± 8249 mm Hg/min). The number of PET viable segments was a predictor of the postoperative increase in the RPP in univariate (P <.04) and multivariate analyses (P <.001). In contrast, LDDE did not bear any prognostic information about improvement in the RPP. Conclusions This study confirms earlier findings of higher sensitivity and lower specificity of PET compared with LDDE in predicting improvement of regional left ventricular function after revascularization. However, the feasibility of predicting postrevascularization improvement of exercise parameters seems unique for PET. The potential prognostic value of this finding needs further investigation. (Am Heart J 2000;140:928-36.)

Prognostic impact of myocardial viability testing in 3088 patients: A meta-analysis

Prognostic impact of myocardial viability testing in 3088 patients: A meta-analysis