Dr. Korea University Anam Hospital Seoul, Seoul-t'ukpyolsi, Republic of Korea
Objectives: To evaluate the safety and feasibility of an early phase 1 submaximal cardiopulmonary exercise test (CPET) in patients who have undergone cardiac surgery.
Design: Twenty ambulatory patients who underwent cardiac surgery were referred to the CR department on the fifth-day post-surgery and initiated the CR program. A CPET was performed nine days after the surgery. Participants initiated the test at 0 Watts and the workload was increased by 20 Watts after 2 minutes. During the test. researchers evaluated parameters including estimated peak values of oxygen consumption (peak VO2), metabolic equivalent of task (MET), respiratory exchange ratio (RER), blood pressure, heart rate (HR), and the rating of perceived exertion(RPE). Moreover, the grip strength test, 6-minute walk test (6MWT), squat endurance test, Korean activity scale/index (KASI), EuroQol-5 dimension (EQ5D), and short-form 36-item health survey (SF36) were measured.
Results: Twenty patients (75 % male, average age of 62.50 ± 1.99 years) underwent CPET. The average exercise duration of CPET was 411.75 ± 168.25 seconds. During the test, peak VO2 was recorded as 12.32 ± 0.75 ml/kg/min (corresponding to 46.65 ± 2.08 % of VO2 max). The peak RER was 1.01 and the peak RPE was recorded as 15.00 ± 0.51. Furthermore, the peak HR observed was 111.8 ± 3.76 beats/min (equivalent to 70.95 % of age-predicted maximal HR). Adjusting for sex and age, we found significant positive correlations between VO2 peak and 6MWT, squat endurance test, KASI, and the physical component summary (PCS) of the SF36 questionnaire. The 6MWT showed a correlation coefficient (r) of 0.522 (p=0.026), the squat endurance test had an r of 0.628 (p=0.005), KASI had an r of 0.586 (p=0.011), and the PCS of SF-36 also exhibited an r of 0.546 (p=0.019).
Conclusions: The findings suggest that performing CPET during the early phase 1 CR appears to be safe and feasible.
