Accuracy of exhaled nitric oxide measurements for the diagnosis of bronchiolitis obliterans syndrome after lung transplantation.
BACKGROUND
Exhaled nitric oxide (eNO) is increased in patients with bronchiolitis obliterans syndrome (BOS) after lung transplantation. However, the accuracy of eNO measurements in diagnosing BOS is unknown.


METHODS
Thirty-two lung-transplant patients were included. Their immunosuppressive regimen consisted of cyclosporin A (tacrolimus), azathioprine (mycophenolate mofetil), and oral but no inhaled steroids. eNO levels and spirometry were prospectively followed until 2 years after transplantation or until the patient developed BOS.


RESULTS
Thirteen patients (group A) developed BOS (607 +/- 158 days after transplantation). Their mean eNO level at that time was 24.3 +/- 13.2 parts per billion (ppb), whereas the eNO value in the stable patients at 2 years (group B) was 11.4 +/- 4.9 ppb, P=0.0054. All group A patients had an eNO of 15 or greater ppb. Seven patients of group B also had an eNO of 15 or greater ppb, resulting in a test accuracy for the diagnosis of BOS of 0.78. However, considering only those patients who had two consecutive measurements (3-6 weeks apart) of eNO 15 or greater ppb during the months preceding the diagnosis of BOS or in the whole 2-year evaluation period, only 3 of 19 patients in group B (false-positives) but 12 of 13 in group A (1 false-negative) now fulfilled that criteria, which became positive at a mean of 263 +/- 169 days before the diagnosis of BOS was met, based on the forced expiratory volume in 1 second criteria. This increased the accuracy to 0.88.


CONCLUSIONS
Measurements of eNO appear to be an accurate test for the early diagnosis of BOS.
Verleden
Geert M
GM
Department of Respiratory Diseases, University Hospital Gasthuisberg, 49 Herestraat, B-3000 Leuven. geert.verleden@uz.kuleuven.ac.be
Dupont
Lieven J
LJ
Van Raemdonck
Dirk E
DE
Vanhaecke
Johan
J
D000328:Adult; D001944:Breath Tests; D001989:Bronchiolitis Obliterans / Q000175:diagnosis*; D005260:Female; D006801:Humans; D016040:Lung Transplantation / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000032:analysis*; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D009569:Nitric Oxide