The heart rate response to adenosine: A simple predictor of adverse cardiac outcomes in asymptomatic patients with type 2 diabetes.
Int J Cardiol. 2012 Sep 12;
Authors: Hage FG, Wackers FJ, Bansal S, Chyun DA, Young LH, Inzucchi SE, Iskandrian AE
BACKGROUND: The Detection of Ischemia in Asymptomatic Diabetics (DIAD) study demonstrated a low 5-year hard cardiac event rate. We hypothesized that a blunted heart rate response (HRR, maximum percent change) to adenosine, a simple marker of cardiac autonomic neuropathy, will identify a cohort at higher cardiac risk. METHODS: In DIAD, 518 participants were randomized to screening adenosine myocardial perfusion imaging (MPI) and had available data. HRR <20% was considered abnormal. The primary endpoint was a composite of nonfatal myocardial infarction and cardiac death. RESULTS: During 4.7±0.9years of follow-up 15 (3%) participants experienced the primary outcome. Participants with lower HRR experienced more events than those with higher HRR (8%, 3%, 1%, for HRR <20% (n=79), 20-39% (n=182) and ?40% (n=257), respectively, p=0.01). In a Cox proportional regression model that included MPI abnormalities and HRR, both were independently associated with cardiac events (p for model <0.001). HRR <20% was associated with 9-fold increased risk (p=0.007) and moderate/large abnormal MPI was associated with 6-fold increased risk (p=0.004). Participants with both abnormal MPI and HRR (n=8) were at highest risk for cardiac events (38%) whereas those with HRR ?40%, irrespective of MPI abnormalities (n=234), were at extremely low risk (?1%, log-rank p<0.001). CONCLUSIONS: In DIAD, abnormal HRR to adenosine infusion is an independent predictor of cardiac events. This easily obtained marker of cardiac autonomic neuropathy identifies asymptomatic patients with type 2 diabetes mellitus at increased risk, particularly when associated with abnormal MPI, who may warrant further testing and more aggressive cardiovascular risk factor management.
PMID: 22981277 [PubMed - as supplied by publisher]