CARDIOPULMONARY EXERCISE TESTING IN THE EVALUATION OF PATIENTS WITH VENTILATORY VS CIRCULATORY CAUSES OF REDUCED EXERCISE TOLERANCE

Introduction: Cardiopulmonary exercise testing (CPX) is considered a u seful procedure in the evaluation of circulatory, ventilatory, or mixe d origin of reduced exercise tolerance. Our study was designed to comp are CPX and a standard clinical-instrumental approach in the evaluatio n of patients with cardiopulmonary disorders. Methods: Fifty-seven pat ients (31 male, 26 female; mean [+/-SE] age, 60+/-2 years) were studie d. Each patient was evaluated by two different observers: one used sta ndard clinical criteria, the other used gas exchange indexes, monitore d during a maximal incremental CPX, performed on a cycle ergometer; Ca rdiac output (CO), at rest and at submaximal work level, was also obta ined. Results: In 46 patients (80.7 percent), a concordant evaluation was reached by the two observers (24 were found to have a predominant ventilatory disorder, to have a circulatory disorder); among these, su bjects considered to have circulatory impairment, the maximal CO/maxim al workload ratio was significantly lower than in the ventilatory grou p; in those with ventilatory impairment, the reduced exercise toleranc e correlated with the resting spirometric values. In the remaining 11 patients (19.3 percent), CPX better defined the underlying pathophysio logy of exercise limitation: in 10 of them, clinically classified as h aving a mixed or predominantly ventilatory disorder, a greater importa nce of the circulatory component was detected; 4 had evidence of pulmo nary vascular impairment (high VE/V-CO2 at -anaerobic threshold). Conc lusions: Our study confirmed the sensitivity of CPX in the evaluation of a reduced exercise tolerance in dyspneic patients with cardiopulmon ary conditions; when compared with a clinical-laboratory approach, in some patients it allowed the detection of an underestimated circulator y component causing exercise limitation.