Diagnostic cardiopulmonary exercise testing (DXT) identifies pathophysiological limitations to exercise performance enabling appropriate medical management and therapeutic interventions. Availability of compact, portable and reliable apparatus has made DXT more widely available. We report 485 sequential tests performed in general physician offices by a network of skilled providers using centralized data management and novel algorithms for physiological interpretation.
The patients were 299 men and 186 women, mean age (SD) was 48 (11) years, height 1.73 (0.01) m, weight 90.9 (19.7) kg. Symptoms noted on referral included: chest discomfort 27%, exertional dyspnea 16% and fatigue 3%. Identified risk factors were: obesity 45%, hypertension 34%, family history of coronary artery disease 21%, dyslipidemia 27%, current smoking 17% and diabetes mellitus 6%.
Patients were assigned to one of four diagnostic categories: (A) cardiovascular impairment (CI) due to myocardial ischemia, major dysrhythmia or abnormal chronotropic index (fC/VO2), (B) ventilatory limitation (VL) when VE was <85% predicted and within 15 L/min of MVV, (C) both CI and VL, (D) neither CI nor VL.CONCLUSIONS: The distribution of patients was as follows: A 14%, B 9%, C 2% and D 75%. Those in categories A, B and C (25%) warranted further investigation or specialist referral. In category D, 177 (36%) had physical deconditioning without evidence of more concerning cardiovascular abnormalities. They were advised to have repeated testing in 6 months and given a scientifically derived exercise prescription. Another 135 (28%) had exaggerated hypertensive responses indicating suboptimal blood pressure control or risk of future hypertension and 148 (31%) had functional impairment due to obesity.
Referring physicians were provided with physiological interpretations for clinical correlation enabling them to decide about further investigation or specialist referral. This approach to exercise testing conveniently and cost-effectively identifies early cardiovascular and pulmonary disease, distinguishes physical deconditioning in the absence of more concerning abnormalities, facilitates exercise prescription and thus empowers general practitioners in their medical decision making.
C.B. Cooper, Viasys Healthcare, Inc, University monies.