An angiographic and clinical study of coronary collateral circulation

Functional significance of coronary collateral perfusion in preserving myocardial integrity

Coronary collateral perfusion to the completely obstructed coronary artery was evaluated by coronary cineangiography in 32 patients. In 13 patients, there was neither history of severe chest pain of longer than 30-min duration nor electrocardiographic evidence of a transmural myocardial infarction (Group I). Among patients undergoing intracoronary thrombolytic therapy for the completely occluded infarct-related coronary artery within 6 h after the onset of symptoms of the first acute myocardial infarction, 19 patients had a history of preinfarction angina (Group II). Collateral visualization (collateral index) was found to be significantly greater in Group I (2.5 +/- 0.5, SD) than in Group II (0.9 +/- 1.0) (p less than 0.01). Group I patients had a longer history of angina (25 +/- 25 months) than did Group II patients (17 +/- 18 months) (p = NS). These findings indicate that well-developed coronary collateral vessels preserve myocardial integrity upon acute coronary occlusion and that a long-standing angina indicative of myocardial ischemia may play an important role in developing collateral channels.

A modified regionally ischemic porcine heart preparation with eligible residual blood flows

The left anterior descending coronary artery was occluded in each of 28 thoracotomized pigs around an intracoronary catheter for periods between 30 and 240 min followed by 90 min of reperfusion. The catheter was connected via an external pump with another arterial catheter. The pump rate was set to deliver 1.5 ml (group I), 3 ml (group II), or 6 ml blood/min (group III) respectively during ischemia. The distribution of the residual blood flow during ischemia was determined in group II with non-radioactive microspheres. We delineated the risk region by a fluorescent dye and the infarcted tissue with a tetrazolium stain. The higher residual blood flow in groups II and III reduced the incidence of ventricular fibrillation during ischemia from 70% (group I) to 28%, suggesting that the amount of residual blood flow is one important determinant for this rhythm disturbance. The subendocardial-subepicardial blood flow ratio in the risk region of the anterior wall was 41%. Infarcts started to develop after 30 min of ischemia (groups I and II). In all groups necrosis progressed most rapidly within the first 90 min of ischemia indicating that besides the beneficial effect of a high residual blood flow only early reperfusion is able to salvage a substantial amount of jeopardized myocardium. Compared to conventional regionally ischemic canine and porcine heart preparations the described model offers the following advantages: Accurate delineation of the risk region, eligible residual blood flow, reduction of ventricular fibrillation with higher residual blood flows, and the possibility to selectively test the metabolic influence of drugs on ischemic injury while avoiding systemic effects.

Evaluation of coronary collateral circulation in conscious humans

The physiologic importance of coronary collateral vessels was investigated in 19 men undergoing transient proximal occlusion of the left anterior descending (LAD) branch without sedative medication. No vasodilators were given before LAD balloon occlusion. Six men had angiographic filling of the LAD via coronary collateral vessels (Group 1) and 13 did not (Group 2). Aortic, distal coronary and left ventricular (LV) filling pressures and great cardiac vein blood flow (thermodilution) were recorded continuously during occlusion. During LAD occlusion, clinical and electrocardiographic evidence for transient myocardial ischemia occurred more often in patients in Group 2 than in Group 1, but the difference was not statistically significant. Heart rate and aortic and distal coronary pressures were similar in Groups 1 and 2. LV filling pressure was 3 mm Hg higher in Group 2 patients (p less than 0.05). The aortic to distal coronary pressure difference and the distal coronary to LV filling pressure difference were also similar in Groups 1 and 2. However, residual great cardiac vein flow was 55% higher (p less than 0.05) and the calculated coronary collateral resistance index was 45% lower in patients in Group 2 compared with those in Group 1 (p less than 0.01). Coupling of regional coronary venous blood flow estimates to pressure measurements routinely made during angioplasty is a new technique that allows evaluation of determinants of coronary collateral function in conscious humans.(ABSTRACT TRUNCATED AT 250 WORDS)