PT  - JOURNAL ARTICLE
AU  - S.J. Scheidl
AU  - C. Englisch
AU  - G. Kovacs
AU  - F. Reichenberger
AU  - R. Schulz
AU  - A. Breithecker
AU  - H-A. Ghofrani
AU  - W. Seeger
AU  - H. Olschewski
TI  - Diagnosis of CTEPH vs. IPAH using capillary to end-tidal CO2 gradients
AID  - 10.1183/09031936.00109710
DP  - 2011 Jan 01
TA  - European Respiratory Journal
PG  - erj01097-2010
4099  - http://erj.ersjournals.com/content/early/2011/07/07/09031936.00109710.short
4100  - http://erj.ersjournals.com/content/early/2011/07/07/09031936.00109710.full
AB  - Chronic thromboembolic pulmonary hypertension (CTEPH) represents an important differential diagnosis to idiopathic pulmonary arterial hypertension (IPAH). We hypothesized that the capillary to end-tidal CO2 gradient at rest and during exercise might help differentiate CTEPH from IPAH.Patients who presented with unequivocal IPAH or CTEPH according to ventilation/perfusion scan, pulmonary angiography, computed tomography and right heart catheterization were included in this retrospective study and compared to healthy controls.Twenty-one IPAH patients and 16 CTEPH patients fulfilled the inclusion criteria. Hemodynamics and peak oxygen uptake were comparable but respiratory rates at rest and during exercise were significantly higher in CTEPH than in IPAH. End-tidal CO2 was significantly lower in CTEPH vs. IPAH at rest and during exercise, while capillary CO2 values were similar. Correspondingly, capillary to end-tidal CO2 gradients were significantly increased in CTEPH vs. IPAH at rest and during exercise: median (range) [mmHg]: 8.6 (3.0;13.7) vs. 4.4 (0.9;9.0), p<0.001, and 9.3 (3.3;13.1) vs. 4.1 (0.0;8.8), p<0.001. Although these values were closer to normal in IPAH they were still significantly elevated as compared to healthy controls: 2.3 (−4.8;8.1) and −1.9 (−5.7;6.2).Capillary to end-tidal CO2 gradients may help to distinguish CTEPH from IPAH based on resting and exercise values.