[Effect of atrial natriuretic factor on coronary vascular tone]

To test whether atrial natriuretic factor (ANF) may be involved in the modulation of coronary vasomotor tone, ANF was injected into angiographically normal left coronary arteries. Measurement of epicardial diameters of the circumflex (Cx) and left anterior descending artery (LAD) were made from biplane angiograms by an automatic contour-detection system. Bolus injection of ANF (0.07 micrograms/kg, diluted in 1 ml 0.9% NaCl, n = 7) increased diameter of proximal segments of LAD (11 +/- 4%) and Cx (10 +/- 4%) (p less than 0.02 each vs control) without altering heart rate and mean arterial pressure (MAP). Intracoronary nitroglycerin (NTG, 0.3 mg) increased diameters of identical LAD and Cx segments by 18 +/- 3% and 20 +/- 4%. Intracoronary ANF infusion (0.02 micrograms/kg/min over 5 min, followed by 0.1 micrograms/kg/min, n = 10) exerted dose-dependent increases in diameters of LAD and Cx (low dose: + 5 +/- 2%, p less than 0.05 vs control; high dose: + 13 +/- 3%, p less than 0.01 vs control). ANF-infusion increased arterial plasma ANF levels from 280 +/- 80 pg/ml during control to 894 +/- 82 pg/ml (low dose; + 614 pg/ml vs control) and to 2290 +/- 228 pg/ml (high dose). Severe ischemia in four patients undergoing angioplasty exerted substantial increase in arterial ANF levels (160 +/- 60 to 608 +/- 111 pg/ml; + 448 pg/ml vs control), similar to the increase elicited by low dose ANF infusion in man.(ABSTRACT TRUNCATED AT 250 WORDS)