Arm exercise myocardial perfusion imaging for prognostication of long-term outcome

Pharmacologic evaluations constitute ≥50% of imaging stress tests, but exercise reduces adverse effects, improves myocardial perfusion imaging (MPI) quality and diagnostic results, and provides powerful prognostic and clinically important information on exercise capacity and cardiovascular responses to the relevant physiologic stress of exercise. Thus, our purpose was to determine whether arm exercise and MPI variables predict long-term outcome in patients who cannot perform leg exercise.

We performed arm exercise MPI stress tests in 253 consecutive patients age 64.5 (10.7) yr (mean (SD)) from 1997 to 2002 and investigated associations of arm exercise and abnormal MPI variables with all-cause mortality, myocardial infarction (MI), coronary artery bypass grafting (CABG), and percutaneous coronary intervention (PCI) during follow-up of 12.0 (1.3) yr.

There were 156 deaths (61.7%), 47 patients suffered MI (18.6%), 24 underwent CABG (9.5%), and 50 had PCI (19.8%). Arm exercise capacity and delta HR (peak - resting) were strongly associated with survival after adjustment for significant demographic and clinical variables (Cox multivariate P < 0.0001 and 0.001, respectively). MPI was abnormal in 157 patients (62.1%). An abnormal arm exercise MPI was borderline predictive of mortality by Cox analysis (71.8% vs 46.4% for normal study; univariate P < 0.0001; multivariate P = 0.07) but resulted in 58% relative incremental integrated discrimination improvement over clinical variables for predicting death. Perfusion defect size also strongly predicted mortality (Cox multivariate P = 0.003). An abnormal arm exercise MPI study, perfusion defect type, and size all prognosticated PCI (all P ≤ 0.03) but not MI or CABG.

Arm exercise MPI is a valuable approach for outcome prediction in patients unable to perform leg exercise.