Prognostic utility of myocardial blood flow assessed by flow assessed by N-13 ammonia positron emission tomography in patients with idiopathic dilated cardiomyopathy

Previous studies in patients with idiopathic dilated cardiomyopathy (IDC) h ave suggested that myocardial perfusion is impaired and spatially heterogen eous in such cases. Our objective was to identify any association between a n abnormality in myocardial perfusion and the prognosis of patients with ID C. We collected data on N-13 ammonia positron emission tomography (PET) stu dies performed in 26 patients with IDC (9 nonsurvivors, 17 survivors) and i n 8 normal control subjects. Regional myocardial blood flow (rMBF) was quan tified using N-13 ammonia positron emission tomography and the Simple flow model. The spatial heterogeneity of myocardial perfusion was assessed by ca lculating the coefficient of variance of rMBF. Mean rMBF of the survivors w as significantly lower (0.54 +/- 0.13 ml/min/g) than that of control subjec ts (0.66 +/- 0.06 ml/min/g) (p = 0.03 vs control), but did not differ signi ficantly between nonsurvivors (0.58 +/- 0.15 ml/min/g) and control subjects . The coefficient of variance of rMBF was significantly higher in nonsurviv ors than in either survivors or control subjects (0.24 +/- 0.08 vs 0.15 +/- 0.08, p = 0.007, and 0.16 +/- 0.05, p = 0.03, respectively). probability o f 3-year survival (Kaplan-Meier method) was 33.0% in subjects whose coeffic ient of variance of rMBF was above the median compared with 90.0% in subjec ts whose coefficient of variance of rMBF was below the median (p = 0.01). T he probability of 3-year survival did not differ among subjects whose mean rMBD was above versus below the median (61.5% vs 62.9%, respectively). The results suggest that the prognosis of patients with IDC is associated with the spatial heterogeneity of myocardial perfusion, not with initial absolut e rMBF. (C) 1999 by Excerpta Medico, Inc.