[Evaluation of the validity of spiroergometric parameters in the differentiation of circulatory and ventilatory physical limitation].
BACKGROUND
One of the indications postulated for cardiopulmonary exercise testing (CPX) is the distinction between ventilatory and cardiocirculatory reasons of an exercise limitation. Though data such as anaerobic threshold, breathing- and heart-rate-reserve, difference of arterial and alveolar oxygen pressure, ratio of ventilation to O2 and CO2 output and aerobic capacity are commonly considered in CPX interpretation, exact choice of parameters and cut-off-points is not definitely clear. The aim of our study therefore was to scrutinize the validity of these parameters and the recommended cut-off-points. A second goal was to evaluate the reliability of a standardized CPX interpretation as postulated by Wassermann and Palange.


METHODS
We examined 19 patients with congestive or ischemic cardiomyopathy, 24 subjects with chronic obstructive or interstitial lung disease (n = 11 resp. n = 13). The control group consisted of 15 healthy people. During incremental cycle exercise we measured the ventilatory frequency, the peak O2 uptake and the oxygen pulse as well as the above mentioned parameters. Data were interpreted according to Wassermann and Palange in order to confirm the diagnosis of a cardiocirculatory or ventilatory conditioned exercise limitation. Additionally we determined the cut-off-points with the highest diagnostic value for our patient groups.


RESULTS
According to Palange only 7% of the diagnosis could be confirmed, 55% were correctly ascertained by data interpretation according to Wassermann. Breathing reserve (45% of maximum voluntary ventilation) proved to be the only parameter with satisfying selectivity (sensitivity = 75%; specificity = 95%). Diagnostic value of all other recorded data was worse by far.


CONCLUSIONS
Our study shows that standardized interpretation of CPX data does not lead to the correct diagnosis in a satisfying percentage. In any case results have to be confirmed by conventional tests such as ECG or spirometry, so that the additional diagnostic value of CPX in patients with an exercise limitation of unknown origin has to be seen very critically. Except breathing reserve from our point of view there is still no valid parameter or cut-off-point to distinct cardiocirculatory from ventilatory exercise limitation that can be recommended.
Reuter
M
M
Medizinische Klinik III, Universität zu Köln.
Wassermann
K
K
D000328:Adult; D000368:Aged; D002245:Carbon Dioxide / Q000097:blood; D004562:Electrocardiography; D005080:Exercise Test / Q000379:methods*; D005260:Female; D006333:Heart Failure / Q000175:diagnosis* / Q000503:physiopathology; D006801:Humans; D008173:Lung Diseases, Obstructive / Q000175:diagnosis* / Q000503:physiopathology; D008176:Lung Volume Measurements; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000175:diagnosis* / Q000503:physiopathology; D010100:Oxygen / Q000097:blood; D011658:Pulmonary Fibrosis / Q000175:diagnosis* / Q000503:physiopathology; D013147:Spirometry / Q000379:methods*
D002245:Carbon Dioxide; D010100:Oxygen