ATRIAL-NATRIURETIC-PEPTIDE AUGMENTS CORONARY COLLATERAL BLOOD-FLOW - A STUDY DURING CORONARY ANGIOPLASTY

Background and hypothesis: In vitro studies have shown that atrial nat riuretic peptide (ANP) causes relaxation of preconstricted blood vesse l strips and inhibits the contraction of isolated vessels in response to norepinephrine and angiotensin II. The present study examined the e ffects of exogenous ANP on the coronary collateral blood flow during a ngioplasty. Methods: We studied 15 patients undergoing elective balloo n angioplasty during the second and third balloon inflations. A Dopple r flow guidewire was advanced distal to the lesion and used for the es timation of coronary blood flow velocity. After the second balloon inf lation, 25 ng/kg/min of ANP were administered intracoronarily for 8 mi n. Electrocardiogram, pressure, and flow velocity were recorded immedi ately 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 th e 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 ameliorate s myocardial ischemia during angioplasty.