Cardiopulmonary exercise tests in people with chronic stroke: Interpretation and clinical application.

Abstract

Objective: To understand in people with stroke: (1) reasons for cardiopulmonary treadmill exercise test termination, (2) how frequently secondary criteria indicating a maximal test are met, and (3) how test termination is related to volume of oxygen consumption and participant characteristics.

Design: A secondary analysis from the Promoting Recovery Optimization of Walking Activity in Stroke (NCT02835313) clinical trial.

Setting: Four outpatient rehabilitation clinics.

Participants: People with chronic stroke able to walk without assistance of another person.

Intervention: Participants (n = 250) randomized in a larger clinical trial completed symptom limited graded exercise treadmill tests pre- (n = 247) and post-intervention (n = 185). Treadmill exercise tests were conducted at constant speed with incremental incline increases.

Main measures: The primary measure was reason for cardiopulmonary exercise test termination. Secondary measures included: oxygen consumption, ventilatory threshold, peak heart rate, respiratory exchange ratio, six-minute walk test, and fastest walking speed.

Results: There were six categories of test termination, electrocardiogram (11%), blood pressure/heart rate (13%), biomechanical (25%), self-selected (41%), equipment malfunction (8%), and other (2%). Only 1.9% of tests achieved the threshold to confirm a maximal aerobic effort. There were no differences in peak volume of oxygen consumption or participant characteristics between test termination categories.

Conclusions: Analyses indicate few with chronic stroke exhibit a maximal aerobic effort on a cardiopulmonary exercise test. If the cardiorespiratory system is not thoroughly taxed during treadmill exercise tests in people with chronic stroke, interpreting results as their cardiorespiratory fitness should be done cautiously.