Experimental coronary artery fistula.

Despite numerous clinical reports of coronary artery fistulas, there have been no laboratory models. A circumflex coronary-pulmonary artery fistula was constructed with a vein graft in 11 adult foxhounds. A temporary intravascular shunt obviated the need for cardiopulmonary bypass. Measurements of aortic flow, arterial pressure, left ventricular pressure and its derivative, heart rate, and flow in the proximal coronary, distal coronary, and fistula were made with the fistula open and closed in 9 animals. Mean fistula flow was 89 c.c. per minute, representing a 1.1:1 left-to-right shunt. Mean proximal coronary flow increased 211 per cent, and there was a relative steal of 26 per cent of distal coronary flow with the fistula functioning. Phasic flow patterns showed continuous systolic and diastolic flow in the proximal coronary artery and fistula. Despite the striking changes in coronary flow patterns, there was no significant effect on measured left ventricular function. Futher uses for this model and variations of it aresuggested.