Abstract 318: Myocardial Perfusion Reserve a Stronger Predictor of Survival Than LV Ejection Fraction After a PET Driven Revascularisation
Introduction: Revascularisation strategies based on positron emission tomography (PET) proven viability have been widely accepted. However not all patients treated this way benefit from revascularisation. Atherosclerosis is a disease not limited to epicardial arteries, but also affects the microvasculature. We have previously shown that myocardial perfusion reserve (MPR) influences survival in ischemic heart disease (IHD) patient not amendable for intervention. In the present study we evaluated whether MPR has prognostic value in patients after a PET driven intervention.
Hypothesis: MPR is an important prognostic factor also in revascularised patients
Methods: Between 1995 and 2003 119 consecutive patients with chronic IHD underwent a PET driven revascularization based on dipyridamole stress and rest 13N-ammonia PET to determine MPR as well as an FDG PET for viability (mismatching defects), infarction (matching defects) and LVEF assessment. Patients were followed for cardiac mortality.
Results: One-hundred nineteen patients underwent a PET-driven revascularization (67 PCI, 52 CABG). The mean age of the patients was 67±11 (97 men). MPR was 1.54±0.43. Patients were divided into tertiles based on the MPR (inter-tertile boundaries: 1.33 and 1.68). In the lowest and middle MPR tertiles significantly more cardiac deaths were observed than in the highest tertile. The age and sex corrected hazard ratio for the middle tertile was 7.9 (95% CI: 0.97 - 64.9) and for the lowest tertile 24.5 (95% CI: 3.2 – 186.2) (p=0.001). Also LV ejection fraction (LVEF) was of prognostic significance: HR for the middle tertile 1.7 (95%CI 0.5– 6.4) and for the lower tertile 4.8 (1.4 –16.0; p=0.015). After adding LVEF to the model MPR remained significant with HR’s of 6.5 (0.8 –54.4) and 18.5 (2.3 –145.5)(p=0.004), whereas LVEF did not reach significance in this model. No difference in percentage mismatch between the three groups was observed (13.7±10.8% in the lowest, 13.6±11.7% in the middle and 11.1±9.6% in the highest MPR tertile)
Conclusion: Patients with IHD revascularized based on PET viability assessment who have a low MPR are at risk of cardiac death. In addition to viability the MPR results of the PET scan should be taken into account.