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Prognostic value of rest-redistribution tomographic thallium-201 imaging in ischemic cardiomyopathy
1Philadelphia Heart Institute, Presbyterian Medical Center, Pennsylvania 19104, USA.
Insights
Viable myocardium in patients with coronary artery disease and left ventricular dysfunction indicates a poor prognosis with medical therapy. Coronary revascularization significantly improves survival rates in these patients.
Area of Science:
- Cardiology
- Nuclear Medicine
- Cardiovascular Imaging
Background:
- Prognostic implications of viable myocardium in coronary artery disease (CAD) with left ventricular (LV) dysfunction are not fully understood.
- Rest-redistribution thallium-201 imaging is a key diagnostic tool in assessing myocardial viability.
Purpose of the Study:
- To evaluate the prognostic value of thallium-201 single-photon emission computed tomographic (SPECT) imaging in patients with CAD and LV dysfunction.
- To compare outcomes between medical therapy and coronary revascularization in patients with significant myocardial viability.
Main Methods:
- Retrospective analysis of 85 patients with CAD and LV dysfunction, divided into medical therapy (n=47) and coronary revascularization (n=38) groups.
- Rest-redistribution thallium-201 SPECT imaging to assess myocardial viability, quantified by the number of viable segments per patient.
- Follow-up for mortality over a mean period of 31 months.
Main Results:
- No significant difference in the extent of CAD, LV ejection fraction, or number of viable myocardium segments between the two groups.
- Higher mortality rates in the medical therapy group (34% deaths, 13% annual mortality) compared to the revascularization group (16% deaths, 6% annual mortality).
- Actuarial survival analysis indicated a trend towards better survival in the revascularization group (p=0.056).
Conclusions:
- Presence of viable myocardium in patients with CAD and LV dysfunction is associated with a poor prognosis when treated medically.
- Coronary revascularization appears to improve prognosis and survival in this patient population.
- Thallium-201 SPECT imaging is valuable for risk stratification in patients with CAD and LV dysfunction.
Abstract:
The relation between the presence of viable myocardium by rest-redistribution thallium imaging and prognosis is not well defined. This study examined the prognostic value of rest-redistribution single-photon emission computed tomographic imaging with thallium-201 in patients with coronary artery disease (CAD) and left ventricular (LV) dysfunction. Patients were divided into 2 groups: group 1 patients (n = 47) were treated medically and group 2 patients (n = 38) underwent coronary revascularization. The 2 groups were comparable in the extent of CAD and in LV ejection fraction. Thallium images showed normal tracer uptake in 1 group 1 and 3 group 2 patients, fixed defects in 26 group 1 and 18 group 2 patients, and both reversible and fixed defects in 20 group 1 and 17 group 2 patients (p = NS). Based on analysis of 20 segments/patient, reversible defects were seen in 4 +/- 4 segments/patient in group 1 and 5 +/- 5 segments/patient in group 2 (p = NS). Viable myocardium (defined as normal tracer uptake, reversible defects, or mild fixed defects) was seen in 14 +/- 4 segments/patient in group 1 and 15 +/- 5 segments/patient in group 2 (p = NS). During a mean follow-up of 31 months, there were 16 group 1 (34%) and 6 group 2 (16%) deaths. The annual mortality rate was 13% in group 1 and 6% in group 2. Actuarial survival analysis showed better survival in group 2 than in group 1 (p = 0.056). Thus, viable myocardium in patients with CAD and LV dysfunction is associated with poor prognosis with medical therapy. Coronary revascularization improves prognosis.