Angiotensin-converting enzyme as a possible marker for lung toxicity in amiodarone-treated patients.

Since it has been observed that in vitro amiodarone induces morphological alterations in endothelial cells similar to those observed in patients with lung toxicity and that the angiotensin-converting enzyme (ACE) seems to be a marker for perturbation of the alveolar-capillary membrane, serum ACE concentrations have been determined in 44 patients, 23 treated with amiodarone (group A) and 21 treated with other anti-arrhythmic drugs (group B), before the beginning of treatment and after 7, 15, 30, 60 and 180 days. Serum ACE concentrations in group A were lower than the basal values (15.8 +/- 5.9 mU/ml) on day 7 (12.7 +/- 4.5 mU/ml) and were higher on day 60 (17.9 +/- 3.8 mU/ml), then returned to basal values by day 180 (15.9 +/- 5.5 mU/ml), but none of the differences were statistically significant. In group B, serum ACE concentrations were significantly higher than basal values (15.2 +/- 4.0 versus 14.2 +/- 3.5 mU/ml, p less than 0.05) only on day 15. In group A serum ACE concentrations were significantly higher than in group B only on day 60 (17.9 +/- 3.8 versus 14.7 +/- 4.5 mU/ml, p less than 0.025). During the period of the study none of the patients showed any clinical or radiological signs of lung toxicity or reduction of lung diffusion capacity for carbon monoxide (DLCO). Serum ACE levels were normal even in three patients who developed pulmonary fibrosis and in four whose DLCO was reduced by more than 20% from the basal values after the study was completed.(ABSTRACT TRUNCATED AT 250 WORDS)