Mechanisms of collateral development and hemodynamics of gradual coronary occlusion

Summary The mechanisms for development of collaterals following a gradual occlusion (Ameroid technique) of one the coronary arteries in the dog were investigated. A control systems approach, based on quantitative experimental data, was utilized. The peripheral coronary pressure, peripheral coronary...
Ausführliche Beschreibung

Summary The mechanisms for development of collaterals following a gradual occlusion (Ameroid technique) of one the coronary arteries in the dog were investigated. A control systems approach, based on quantitative experimental data, was utilized. The peripheral coronary pressure, peripheral coronary flow, coronary reserve flow, collateral resistance, peripheral coronary resistance, oxygen availability and demand were among the parameters studied. These variables were followed through the preocclusion phase, occlusion phase, ischemic phase, and post-ischemic phase of a gradual coronary constriction. The simulation studies were examined for the following basic assumptions: 1) ischemia is the sole stimulus for collateral development, 2) the peripheral coronary vasculature exhibits autoregulation and the peripheral coronary resistance increases during ischemia, 3) autoregulation occurs but during ischemia the peripheral vasculature remains maximally dilated without increase in resistance, and 4) the peripheral coronary vasculature is non-autoregulatory. It was concluded that neither ischemia nor a pressure differential can solely account for collateral development It is believed that ischemia begins the collateral growth process and it is sustained by the pressure differential (or some manifestation thereof) during the post-ischemic phase. Assumption 2 is most consistent with both physiological and clinical data. The autoregulatory capacity of the peripheral coronary bed allows a constriction of 76% before the resting coronary flow is impaired. Ausführliche Beschreibung