Study of the effect of renal transplantation on methacholine challenge test in patients with end-stage renal failure in Shahid Doctor Labafinejad Hospital in Tehran, Iran

Pulmonary complications are common in patients with chronic renal failure (CRF). The objective of this study was determine the effect of renal transplantation on pulmonary function, using a methacholine challenge test. This interventional study included 14 CRF patients on maintenance dialysis who underwent serial spirometry and astography before and after renal transplantation. None of them was known to have clinically important pulmonary or heart disease. The results of spirometry, astography, echocardiography, and chest X-ray were normal. Five patients were men and all others were women. The overall age range was 15 to 45 years (mean age = 28.6 +/- 10.9). For every patient four times astography was done. The mean values of spirometric and astography indices before and after renal transplantation were within normal limit. But by repeated measure analysis of variance, the results actually showed improved airway responsiveness (although within normal limits). The most common pathological lung condition in CRF is pulmonary edema, usually due to a combination of fluid overload and abnormal permeability of the pulmonary microcirculation. However, our patients had no symptomatic pulmonary edema, but minor degrees of fluid retention are virtually impossible to detect clinically and could not be excluded. Therefore, it seems that disappearance of subclinical pulmonary edema was the likeliest cause of an increase in minimum dose of methacholine, and therefore improvement in airway responsiveness after renal transplantation.