Prognostic value of myocardial viability recognized by low-dose dobutamine echocardiography in chronic ischemic left
Rosa Sicari1, Eugenio Picano, Lauro Cortigiani
1CNR, Institute of Clinical Physiology, Pisa, Italy. rosas@ifc.cnr.it
Insights
Myocardial viability, identified by dobutamine echocardiography, predicts better survival in patients with severe left ventricular dysfunction who undergo revascularization. This finding highlights the importance of assessing viability for guiding treatment decisions.
Area of Science:
- Cardiology
- Echocardiography
- Clinical Prognosis
Background:
- Left ventricular (LV) dysfunction post-myocardial infarction (MI) significantly impacts patient outcomes.
- Assessing myocardial viability is crucial for guiding revascularization strategies in ischemic cardiomyopathy.
Purpose of the Study:
- To evaluate the prognostic significance of myocardial viability, assessed by contractile response to inotropic stimulation, in patients with severe LV dysfunction.
- To determine if myocardial viability predicts cardiac death in patients undergoing revascularization.
Main Methods:
- A prospective, multicenter observational study enrolled 425 patients with coronary artery disease, prior MI, and severe LV dysfunction (ejection fraction <35%).
- Low-dose dobutamine echocardiography was used to assess myocardial viability, defined as a wall motion score index (WMSI) improvement of ≥0.40.
- Patients were followed for a median of 3.1 years, with cardiac death as the primary endpoint.
Main Results:
- Among 188 revascularized patients, cardiac death occurred in 7.7% of those with myocardial viability versus 27.2% without (p <0.003).
- Kaplan-Meier survival estimates showed significantly better outcomes for revascularized patients with myocardial viability (90.1%) compared to those without (62%, p <0.0078).
Conclusions:
- Myocardial viability, identified by low-dose dobutamine echocardiography, is a strong independent predictor of improved survival in patients with severe ischemic LV dysfunction who undergo revascularization.
- Dobutamine echocardiography is a valuable tool for risk stratification and guiding therapeutic decisions in this patient population.
Abstract:
This study assesses the prognostic value of myocardial viability recognized as a contractile response to inotropic stimulation in patients with left ventricular (LV) dysfunction in a large-scale prospective, multicenter, observational study. Four hundred twenty-five patients (mean age 61 +/- 10 years) with angiographically proven coronary artery disease, previous (>3 months) myocardial infarction, and severe LV dysfunction (ejection fraction <35%; mean 28 +/- 6%) were enrolled in the study. Each patient underwent low-dose dobutamine echocardiography (up to 10 microg/kg/min). Myocardial viability was identified as a rest-stress variation (Delta) in the wall motion score index (WMSI), in which each segment was scored from 1 = normal to 4 = dyskinetic in a 16-segment model of the left ventricle. Myocardial viability was identified as an improvement of >/=0.40 in WMSI. All patients were followed for a median of 3.1 years. One hundred eighty-eight were revascularized either by coronary artery bypass grafting (n = 118) or coronary angioplasty (n = 70). The only end point analyzed was cardiac death. In the revascularized group, cardiac death occurred in 4 of the 52 patients with and in 37 of the 136 patients without myocardial viability (7.7% vs 27.2%, p <0.003). Kaplan-Meier survival estimates showed a better outcome for those patients with compared to patients without myocardial viability who underwent coronary revascularization (90.1% vs 62%, p <0.0078). Thus, in severe LV ischemic dysfunction, myocardial viability by low-dose dobutamine echocardiography is associated with improved survival in revascularized patients.
