Variations in serum angiotensin-converting enzyme activity following lung resection: a controlled study in a clinical setting.

Angiotensin-converting enzyme (ACE) plays an important role in post-operative cardiovascular control, especially in critical illness. Since the pulmonary endothelium is the major site of ACE production it would seem probable that surgical resection of lung tissue would significantly influence serum ACE (sACE) activity. The aim of this study was to investigate the effect of surgery on early post-operative sACE activity in patients undergoing lung resection (n = 18) and a control group of patients (n = 18) undergoing thoracotomy for other reasons. An early post-operative, sustained sACE fall without significant difference in sACE activity between the two groups was observed 6 h after the operation. Furthermore, there was no correlation between post-operative sACE variations and the amount of lung tissue resected. It appears that surgical removal of lung tissue does not significantly affect the post-operative sACE response. This may be due to the presence of important extra-pulmonary ACE-producing sites or to the compensation of the remaining pulmonary vascular endothelium.