Usefulness of exhaled nitric oxide to guide risk stratification for bronchiolitis obliterans syndrome after lung transplantation.

The aim of this study was to assess fractional exhaled nitric oxide (FeNO) for the early diagnosis of bronchiolitis obliterans syndrome (BOS) after lung transplantation (LTX). 611 FeNO measurements in 166 consecutive patients were classified depending on BOS stage at the time of assessment and course during minimum follow-up of 3 months: (1) stable non-BOS, (2) unstable non-BOS, (3) stable BOS and (4) unstable BOS. Unstable course was defined as new onset of BOS≥1 or progression of BOS. FeNO before unstable course was significantly increased in comparison to their stable counterparts (non-BOS: 28.9 ± 1.2 ppb, n = 40 vs. 16.4 ± 0.8 ppb, n = 131 and BOS: 32.5 ± 1.3 ppb, n = 35 vs. 15.3 ± 0.8 ppb, n = 26; p = 0.01 each). Average time from FeNO reading to onset of deterioration was 117 ± 9 days in non-BOS and 136 ± 9 days in BOS patients. The positive and negative predictive value of FeNO >20 ppb for BOS was 69.0% and 96.9%, respectively. Serial measurements demonstrated significantly lower mean individual variation in stable recipients as compared to stable patients switching to unstable course (3.2 ± 0.3 ppb vs. 12.7 ± 1.4 ppb, p = 0.02). In particular, the excellent negative predictive value of persistently low FeNO readings for future BOS make FeNO assessments a useful tool for continuous risk stratification after LTX.

Inhalation of vasoactive intestinal peptide in pulmonary hypertension.

Pulmonary hypertension (PH) leads to an increased right ventricular workload, cardiac failure and death. In idiopathic pulmonary arterial hypertension (PAH) the vasodilating vasoactive intestinal peptide (aviptadil) is deficient. The aim of the present study was to test the acute effects on haemodynamics and blood gases, and the safety, of a single dose of inhaled aviptadil in chronic PH. A total of 20 patients with PH (PAH in nine, PH in lung disease in eight and chronic thromboembolic PH in three) inhaled a single 100-microg dose of aviptadil during right-heart catheterisation. Haemodynamics and blood gases were measured. Aviptadil aerosol caused a small and temporary but significant selective pulmonary vasodilation, an improved stroke volume and mixed venous oxygen saturation. Overall, six patients experienced a pulmonary vascular resistance reduction of >20%. In patients with significant lung disease, aviptadil tended to improve oxygenation. The pulmonary vasodilating effect of aviptadil aerosol was modest and short-lived, did not cause any side-effects and led to a reduced workload of the right ventricle without affecting systemic blood pressure. Aviptadil inhalation tended to improve oxygenation in patients with significant lung disease. Further studies are needed to evaluate the full therapeutic potential of aviptadil aerosol, including higher doses and chronic treatment.