Myocardial perfusion PET scan predicts cardiac death, especially in diabetes
Among patients who underwent a stress myocardial perfusion PET scan, increasing magnitude of stress myocardial perfusion abnormality was associated with elevated risk for cardiac death, researchers reported.
The relationship was most pronounced in patients with diabetes, according to the researchers.
“The data from the stress test among diabetic patients actually allowed us to better risk-stratify people in greater than 39% of the cases,” Hicham Skali, MD, MSc, associate physician at Brigham and Women's Hospital and instructor of medicine at Harvard Medical School, said in a press release. “Patients with diabetes remain at a significantly higher risk of cardiac death compared to patients without diabetes, and the data from a stress test help us further stratify those at greatest risk.”
Skali and colleagues conducted a retrospective analysis of data acquired prospectively from 7,061 patients (1,966 with diabetes; mean age, 63 years; 47% women; 32.5% with known CAD; 26.8% with previous revascularization) who had a clinically indicated stress myocardial perfusion PET scan.
The primary endpoint was cardiac death. Mean follow-up was 2.5 years.
When the researchers constructed multivariate models accounting for known clinical risk predictors, they found that increasing magnitude of stress myocardial perfusion abnormality conferred higher risk for cardiac death (HR for severe abnormality vs. normal = 7.2; 95% CI, 3.1-16.8).
Adding myocardial perfusion PET results to clinical predictors improved risk reclassification for patients with diabetes (category-based net reclassification index, 0.39; 95% CI, 0.15-0.6), according to the researchers.
In diabetic subgroups, abnormal stress myocardial perfusion PET results were associated with elevated risk for cardiac death (HR = 4.4; 95% CI, 2-9.7) without any interactions for sex, obesity, age, prior revascularization or lack of symptoms, Skali and colleagues wrote.
In patients with diabetes, independent predictors for cardiac death were age and percentage of abnormal myocardium. In patients without diabetes, independent predictors for cardiac death were age, female sex, high cholesterol, resting heart rate and percentage of abnormal myocardium.
“In patients without diabetes, being a woman confers a certain advantage in that their risk of death is much lower, regardless of their stress findings,” Skali said in the release. “However, when you look at patients with diabetes, men and women have relatively the same risk of cardiovascular death, and that risk increases with worsening findings on the PET stress test.” – by Erik Swain
Disclosure: Skali reports he serves on the advisory board of OptimizeRx. Please see the study for all other authors' relevant financial disclosures.