title: Cardiopulmonary exercise testing in the evaluation of patients with ventilatory vs circulatory causes of reduced exercise tolerance.
abstract: BACKGROUND
  Cardiopulmonary exercise testing (CPX) is considered a useful procedure in the evaluation of circulatory, ventilatory, or mixed origin of reduced exercise tolerance. Our study was designed to compare CPX and a standard clinical-instrumental approach in the evaluation of patients with cardiopulmonary disorders.
  
  
  METHODS
  Fifty-seven patients (31 male, 26 female; mean [+/- SE] age, 60 +/- 2 years) were studied. Each patient was evaluated by two different observers: one used standard clinical criteria, the other used gas exchange indexes, monitored during a maximal incremental CPX, performed on a cycle ergometer. Cardiac output (CO), at rest and at submaximal work level, was also obtained.
  
  
  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, 22 to have a circulatory disorder); among these, in subjects considered to have circulatory impairment, the maximal CO/maximal workload ratio was significantly lower than in the ventilatory group; in those with ventilatory impairment, the reduced exercise tolerance correlated with the resting spirometric values. In the remaining 11 patients (19.3 percent), CPX better defined the underlying pathophysiology of exercise limitation: in 10 of them, clinically classified as having a mixed or predominantly ventilatory disorder, a greater importance of the circulatory component was detected; 4 had evidence of pulmonary vascular impairment (high VE/VCO2 at anaerobic threshold).
  
  
  CONCLUSIONS
  Our study confirmed the sensitivity of CPX in the evaluation of a reduced exercise tolerance in dyspneic patients with cardiopulmonary conditions; when compared with a clinical-laboratory approach, in some patients it allowed the detection of an underestimated circulatory component causing exercise limitation.
authors.affiliation: II Patologia Medica, University La Sapienza Rome, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Palange
authors.forename: S
authors.initials: S
authors.lastname: Carlone
authors.forename: S
authors.initials: S
authors.lastname: Forte
authors.forename: P
authors.initials: P
authors.lastname: Galassetti
authors.forename: P
authors.initials: P
authors.lastname: Serra
mesh_terms: D000368:Aged; D002302:Cardiac Output; D002318:Cardiovascular Diseases / Q000150:complications / Q000175:diagnosis*; D004417:Dyspnea / Q000209:etiology*; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D006801:Humans; D008171:Lung Diseases / Q000150:complications / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D015656:Respiratory Mechanics; D012680:Sensitivity and Specificity