Erschienen in:
01.10.2020 | Original Article
A high exercise workload of ≥ 10 METS predicts a low risk of significant ischemia and cardiac events in older adults
verfasst von:
LaVone Smith, MD, Lukasz Myc, MD, Denny Watson, PhD, George A. Beller, MD, Jamieson M. Bourque, MD, MHS
Erschienen in:
Journal of Nuclear Cardiology
|
Ausgabe 5/2020
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Abstract
Background
Patients who achieve ≥ 10 METS during exercise SPECT myocardial perfusion imaging (MPI) have very low rates of significant ischemia and major adverse cardiac events (MACE). It is unknown how many older adults can achieve ≥ 10 METS, and if low risk extends to this subgroup.
Methods and results
We examined the workload achieved, prevalence and predictors of ischemia, and MACE (cardiac death, non-fatal MI, late revascularization) in a cohort of 382 patients ≥ 65 years of age who underwent exercise 99mTc SPECT MPI. The cohort was 64.4% male and 36.9% had known coronary artery disease (CAD). All achieved ≥ 85% of maximum age-predicted heart rate. A workload of ≥ 10 METS was achieved in 25.4%; 50.3% attained 7-9 METS, and 24.4% reached < 7 METS. There was a stepwise decrease in prevalence of any ischemia and significant ischemia (≥ 10% of the left ventricle (LV)) as workload increased (P = 0.037). Patients achieving ≥ 10 METS had a 3.1% prevalence of ≥ 10% LV ischemia (1.2% in those without ST depression). Cardiac death and MACE rates in the ≥ 10 METS subgroup were 0.6%/year and 2.6%/year over a median 7.0 years of follow-up.
Conclusions
A substantial proportion of older adults who undergo exercise SPECT MPI can achieve ≥ 10 METS. This subgroup has low rates of significant LV ischemia and MACE. The favorable diagnostic and prognostic implications of achieving a high workload in an older adult population suggest it is feasible, with certain exceptions, to include this subgroup in workload-based strategies of provisional imaging.