Atrial natriuretic peptide augments coronary collateral blood flow: A study during coronary angioplasty

Background and hypothesis: In vitro studies have shown that atrial natriuretic peptide (ANP) causes relaxation of pre-constricted blood vessel strips and inhibits the contraction of isolated vessels in response to norepinephrine and angiotensin II. The present study examined the effects of exogenous ANP on the coronary collateral blood flow during angioplasty. Methods: We studied 15 patients undergoing elective balloon angioplasty during the second and third balloon inflations. A Doppler flow guidewire was advanced distal to the lesion and used for the estimation of coronary blood flow velocity. After the second balloon inflation, 25 ng/kg/min of ANP were administered intracoronarily for 8 min. Electrocardiogram, pressure, and flow velocity were recorded immediately before each balloon deflation. Fourteen other patients served as controls and received normal saline infusion. Results: Velocity time integral increased from 65 ± 40 to 79 ± 46 mm (p < 0.05) during the third balloon inflation, whereas ST deviation decreased from 1.3 ± 0.9 to 0.7 ± 1.0 mV (p< 0.05). These variables did not change in the control group during the two tested balloon inflations. Conclusion: Exogenous ANP augments coronary collateral blood flow and ameliorates myocardial ischemia during angioplasty.