Methods: Thirty patients diagnosed as coronary artery disease undergoing diagnostic coronary angiography were enrolled in the study. Subjects with chronic obstructive pulmonary disease, asthma, allergic bronchitis, myocardial infarction and documented systolic dysfunction by transthoracic echocardiography were excluded. The respiratory functions of the patients before and immediately after the coronary angiography were measured and arterial blood gas analyses were performed. The subjects were divided into two groups according to results of angiography as having coronary artery disease (Group 1) and without significant coronary artery disease (Group 2). The angiography procedures were performed by a single, experienced angiographer. Left Ventriculography was not performed on any patient

Results: The results gathered before and after angiography procedure were compared. Forced expiratory volume in the first second (FEV₁), maximum mid-expiratory flow rate, (MMFR) 25-75, arterial oxygen pressure (PaO₂) and bicarbonate (HCO₃) were significantly reduced ( p < 0.01), where as forced vital capacity (FVC), pH, oxygen saturation and arterial carbondioxide pressure were not changed. The comparison between two groups resulted that FEV₁ and PaO₂ were significantly decreased after angiography in Group 1.

Conclusions: Diagnostic coronary angiography using iohexol decreases ventilatory functions in a small but significant extent in patients without any overt pulmonary disease. Therefore they should be used cautiously in patients with chronic lung disease.