(CCSP107) IS IT TIME TO CHANGE BLOOD PRESSURE RECOMMENDATIONS FOR EXERCISE TESTING IN SPONTANEOUS CORONARY ARTERY DISSECTION?

Background: Spontaneous coronary artery dissection (SCAD) is a significant cause of acute coronary syndrome predominantly affecting middle-aged women with few traditional cardiac risk factors. In contrast to atherosclerotic myocardial infarction (MI), SCAD-related MI is caused by luminal compression by intramural hematoma. Cardiac rehabilitation (CR) is safe, efficacious, and highly recommended post SCAD. An intake cardiopulmonary exercise testing (CPET) can provide guidance for individualized exercise prescription in CR, but published recommendations suggest conservative blood pressure limits for CPET (e.g., peak BP < 130/80 mmHg). Historically, the risk of SCAD recurrence or propagation with elevations in BP has been a documented concern. The purpose of this case series is to share historical experience with CPET and highlight upper limit BP safety parameters in a SCAD cohort enrolled in CR.

METHODS AND RESULTS: Retrospective analysis of intake CPETs was performed on 47 individuals post SCAD consecutively enrolled in an outpatient CR program in Toronto, Ontario, between 2013 and 2023 (84% female, 50.6±8.5 years, 100% on beta-blockers). Descriptive statistics were used.
Forty-five participants (96%) completed an intake CPET (73% Bruce protocol). Mean time between SCAD event and CPET was 6.4±10.3 months. CPET termination criteria included symptoms, HR, BP, oxygen uptake and physician opinion. BP and HR at rest and peak exercise were 111±16/75±11 mmHg, 68±12 bpm, and 146±20/76±9 mmHg, 131±21 bpm, respectively. Physiological maximum was reached in 31% of the tests. Mean Borg rating of perceived exertion was 13.7±3.2. Thirty-seven participants (82%) achieved a peak BP >= 130/80 mmHg during CPET. One test was terminated due to angina (peak BP 124/72 mmHg, 73% of age-predicted HR, Borg 13). All CPETs were negative for ischemic electrocardiogram abnormalities. SCAD did not recur during exercise testing or the 4-6 months of CR program.

Conclusion: Although BP at peak exercise was above the recommended limits for SCAD, CPET pre-enrollment in CR was safe when conducted in a carefully supervised environment. Individualized thresholds accounting for time since SCAD, pre-event exercise capacity, beta-blocker use, patient goals and ongoing symptoms should be considered. Appropriate exercise testing is key to optimize accurate exercise prescription and subsequent health benefits in this population. Larger, multi-site studies are needed to inform future guidelines and exercise testing parameters for the SCAD patient population.