Retrograde Radioisotope Myocardial Perfusion Patterns in Dogs

Abstract

A retrograde coronary vein injection technique for concentrating radioisotope in ischemic myocardial regions was evaluated in dogs. Potassium-43 in saline solution was injected into the coronary veins during complete closure of the coronary sinus. In the presence of coronary inflow obstruction, the venous potassium-43 was distributed mainly to the low pressure vessels in ischemic heart regions; i.e., the ratio of potassium-43 in the occluded-to-unoccluded areas ranged from 2:1 to 3:1 thirty seconds after retrograde injections. Krypton-85 in saline solution was injected under pressure into the coronary veins during partial closure of the coronary sinus. In the presence of inflow obstruction, the ratio of krypton-85 in the occluded- to-unoccluded areas ranged from 4:1 to 6:1 sixty seconds after retrograde injections; larger ratios may be expected after rapid washout of gas from the normally perfused region is nearly complete. Myocardial potassium-43 imaging techniques were applied to locate and measure the size of the ischemic heart region as a radioisotopic hot spot. Detection of hypoperfused areas of extremely small size may be accomplished by this technique.

Differential effects of synchronized coronary sinus retroperfusion on regional myocardial function during brief occlusion of the left anterior descending and circumflex coronary arteries

“…Shiki et al [38] produced casts of canine myocardial vessels by coronary sinus injection of a low viscosity resin and showed that the apex and left ventricular free wall were well perfused in contrast to the right ventricle and septum which contained well-developed thebesian veins. Cibulski et al [39] demonstrated that potassium-43 injected into the coronary sinus following coronary sinus occlusion was distributed predominantly in myocardium rendered ischemic by occlusion of either the LAD or circumflex coronary arteries. From these experimental observations it would appear that ischemic myocardium in the LAD or circumflex region should benefit equally from retroperfusion.…”