Cardiopulmonary exercise testing is safe for high-risk cardiovascular patients
Image: PD
Key study points:
1. Cardiopulmonary exercise testing is a vital measure of functional impairment in a variety of cardiovascular diseases including CAD, CHF, structural, valvular and congenital diseases.
2. Exercise testing may be very safe even in non-CAD cardiovascular diseases previously thought to be too high-risk for testing-related adverse events.
Primer: Exercise physiological testing measures maximal oxygen uptake (VO2max), which reflects the maximal ability of the patient to take in and utilize oxygen. An abnormally low VO2max indicates functional aerobic impairment, which can be due to reductions in maximum achievable heart rate, stroke volume, or altered relative concentrations of arterial and venous oxygen.
VO2 exercise testing has been utilized to measure exercise capacity and response to treatment in heart failure patients being considered for cardiac transplantation. Other indications for testing include differentiation of cardiac vs. pulmonary etiologies of dyspnea on exertion, and risk stratification in patients with coronary artery disease (CAD) and ischemic cardiomyopathy.
While several studies have demonstrated both the utility and safety of using exercise testing for prognostic monitoring in CAD and heart failure patients, use of this modality in patients with other forms of cardiovascular disease, such as aortic stenosis, hypertrophic cardiomyopathy (HCM), pulmonary hypertension, and congenital heart diseases, remains largely understudied. This paper attempts to answer the question of safety in these populations.
Background reading:
1. ACC/AHA 2002 Guideline Update for Exercise Testing: Summary Article
4. Cardiopulmonary Exercise Testing in the Clinical Evaluation of Patients With Heart and Lung Disease
This [retrospective cohort] study: Cardiopulmonary exercise testing results from 5,060 cardiovascular disease patients with congestive heart failure, aortic stenosis, other valvular diseases, congenital heart disease, HCM, prior cardiac transplantation, pulmonary hypertension and other diseases were surveyed. Echocardiogram results were surveyed when available.
Most patients from this study had symptom-limited testing with termination due to fatigue, dyspnea or angina; the rest were from ECG changes, abnormal blood pressure, patient request or adverse events.
In total, 8 adverse events occurred (0.16%). Of these, none were fatal and 6 were sustained VT which terminated spontaneously. All 8 events occurred in males.
In sum: This large single-center retrospective analysis including several participants with a variety of cardiovascular diseases demonstrated a low rate of adverse events and no fatal outcomes from exercise testing.
Despite the strengths of patient diversity and participant number, the study’s generalizability may be limited by its occurrence at a single academic center. In addition, review of echocardiographic and other data in selected patients was over a wide period relative to timing of exercise testing, limiting accurate correlation of disease status at the time of testing.
In spite of these limitations, the study still demonstrates the safety of this modality in a varied high-risk disease population and warrants reevaluation of current contraindications for such testing.
Click to read the study in Circulation
By [SK] and [MP]
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