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Value of metabolic imaging with positron emission tomography for evaluating prognosis in patients with coronary
M F Di Carli1, M Davidson, R Little
1Department of Pharmacology, University of California Los Angeles School of Medicine 90024-1721.
Insights
Positron emission tomography (PET) can identify viable heart muscle in patients with coronary artery disease (CAD) and severe left ventricular (LV) dysfunction. Revascularization improves survival and heart failure symptoms in these patients with a "mismatch pattern".
Area of Science:
- Cardiovascular Imaging and Intervention
- Nuclear Cardiology
- Heart Failure Management
Background:
- Patients with coronary artery disease (CAD) and severe left ventricular (LV) dysfunction face high mortality.
- Myocardial revascularization may benefit select patients, but prognostic indicators are crucial.
- Assessing myocardial viability is key to guiding treatment decisions in this population.
Purpose of the Study:
- To evaluate the prognostic value of cardiac positron emission tomography (PET) in patients with CAD and LV dysfunction.
- To determine the interrelation between PET findings, medical therapy, and revascularization for survival and heart failure symptom improvement.
- To identify patients who may benefit from revascularization based on myocardial viability assessment.
Main Methods:
- Ninety-three patients with angiographic CAD and LV ejection fraction of 0.25 underwent cardiac PET using N-13 ammonia and 18-F deoxyglucose.
- PET assessed for hypoperfused yet viable myocardium ("mismatch pattern").
- Patients were followed for 13.6 months, with 50 receiving medical therapy and 43 undergoing revascularization.
Main Results:
- The extent of PET-defined "mismatch" negatively impacted survival (p=0.02), while revascularization positively affected survival (p=0.04).
- Patients with mismatch receiving medical therapy had significantly lower annual survival (50%) compared to those without mismatch (92%, p=0.007).
- Revascularization in patients with mismatch improved survival (88%) versus medical therapy (50%, p=0.03) and predicted heart failure symptom improvement (p<0.001).
Conclusions:
- The presence of a "mismatch pattern" on PET indicates poor prognosis with medical therapy in CAD patients with severe LV dysfunction.
- Revascularization in patients with PET-identified myocardial viability appears to improve both survival and heart failure symptoms.
- Cardiac PET is a valuable tool for risk stratification and guiding therapeutic decisions in this high-risk patient group.
Abstract:
Patients with coronary artery disease (CAD) and severe left ventricular (LV) dysfunction have a high but variable annual mortality and some may benefit from myocardial revascularization. This study aimed to evaluate the prognostic value of positron emission tomography (PET), and its interrelation with the choice of medical therapy or revascularization for predicting survival and improvement in symptoms of heart failure in patients with CAD and LV dysfunction. Ninety-three consecutive patients with angiographic CAD and a mean LV ejection fraction of 0.25 who underwent cardiac PET studies for assessment of hypoperfused yet viable myocardium ("mismatch pattern") using N-13 ammonia and 18-F deoxyglucose were followed up for an average of 13.6 months. Fifty patients underwent medical treatment and 43 underwent revascularization. The Cox model analysis showed that the extent of mismatch had a negative effect (p = 0.02), whereas revascularization had a positive effect on survival (p = 0.04). The annual survival probability of patients with mismatch receiving medical therapy was lower than of those without mismatch (50 vs 92%, p = 0.007). Patients with mismatch who underwent revascularization had a higher survival rate than those treated medically (88 vs 50%, P = 0.03). The presence of mismatch also predicted improvement in heart failure symptoms after revascularization (p < 0.001). These results suggest that the presence of mismatch in patients with CAD and severe LV dysfunction is associated with poor annual survival with medical therapy. Revascularization in patients with PET mismatch appears to be associated with improved survival and heart failure symptoms.