Author + information
- Alberto Bouzas-Mosquera, MD* (, )
- Jesús Peteiro, MD, PhD and
- Nemesio Álvarez-García, MD
- ↵*Department of Cardiology, Hospital Universitario A Coruña, As Xubias, 84, 15006 A Coruña, Spain
We read with great interest the paper by Bourque et al. (1) regarding the value of a high exercise workload to rule out significant myocardial ischemia. In that study, only 2 (0.4%) of 473 patients reaching ≥10 metabolic equivalents (METs) and ≥85% of maximum age-predicted heart rate (MAPHR) had ≥10% left ventricular ischemia on myocardial perfusion imaging. Furthermore, of the 430 patients reaching ≥10 METs and ≥85% MAPHR without exercise-induced ST-segment depression, none had significant myocardial ischemia. These results suggest that the information provided by cardiac imaging in these patients is questionable.
Our group previously assessed the prevalence and prognostic value of myocardial ischemia on exercise echocardiography in a population of 1,433 patients with known or suspected coronary artery disease achieving a high exercise workload (defined as ≥10 METs in men and ≥8 METs in women) (2). Of them, in 437 (30%) patients, new or worsening wall motion abnormalities developed during exercise. Over a follow-up of 2.3 ± 1.5 years, 201 (14%) patients underwent coronary revascularization and 57 (4%) patients had a hard cardiac event. Furthermore, exercise echocardiography was shown to provide incremental value for predicting hard cardiac events in these patients.
It might be argued that, in this study, 19% of the patients failed to achieve >85% of MAPHR, and ST-segment changes during the tests developed in 14% of the patients. Thus, we further explored whether the findings obtained by Bourque et al. (1) would replicate in a population of patients fulfilling the criteria used in their study. We recently evaluated 4,004 patients with interpretable electrocardiograms undergoing treadmill exercise echocardiography in whom chest pain or ischemic electrocardiographic changes during exercise did not develop (3). Applying the criteria used in the study by Bourque et al. (1) to this population would yield 2,005 patients who achieved both ≥10 METs and >85% of MAPHR. Of them, new or worsening wall motion abnormalities developed in 301 (15%) patients, 187 (9.3%) patients had ischemia involving at least 3 myocardial segments, and 138 (6.9%) patients underwent coronary revascularization. Thus, these results do not suggest that a high exercise workload may confidently rule out myocardial ischemia or significant coronary artery disease in our patients. It is important to point out that images were acquired at peak exercise, which enhanced the sensitivity of the tests (4).
Although patients achieving a high exercise workload undoubtedly have a better prognosis, a correct diagnosis is still desirable, even when coronary revascularization is not deemed necessary. It would be interesting to validate the results obtained by Bourque et al. (1) at other institutions, with different noninvasive imaging modalities, and using cardiac events or coronary angiography results as end points.
- American College of Cardiology Foundation
- Bourque J.M.,
- Holland B.H.,
- Watson D.D.,
- Beller G.A.
- Bouzas-Mosquera A.,
- Peteiro J.,
- Alvarez-García N.,
- et al.