Evaluation of coronary native and coronary collateral pressure gradients in the conscious dog

Sixteen dogs were instrumented chronically with a left circumflex (CIRC) Ameroid constrictor, and with CIRC, left anterior descending (LAD), aortic, left atrial and pulmonary artery (PA) catheters. Premature mortality was 12.5% prior to the last measurements of pressure at 50 +/- 3 days (mean +/- SE). Five animals developed closure of the Ameroid constrictor at 5 +/- 1 days with an LAD to CIRC pressure gradient of 57 +/- 8 mm Hg. Eleven animals developed closure of the Ameroid constrictor at 18 +/- 1 days with an LAD to CIRC pressure gradient of 29 +/- 3 mm Hg. Three animals in the former group had gross evidence of a myocardial infarction on postmortem examination. None of the animals in the latter group showed evidence of a myocardial infarction. Thus, closure of a CIRC Ameroid constrictor and subsequent collateral vessel development can be monitored chronically by the LAD to CIRC pressure gradient with a high survival, low infarction rate. This chronic model thus provides an accurate measure of coronary native and collateral pressures in unsedated dogs.