The effect of intermittent coronary sinus occlusion on coronary sinus pressure dynamics and coronary arterial flow

The effect of intermittent coronary sinus occlusion (ICSO) with a balloon-tipped catheter on coronary arterial flow and coronary sinus pressure (CSP) dynamics were studied in open-chest dogs. During coronary sinus occlusion (CSO), CSP gradually rose and finally reached a plateau, while left coronary arterial mean flow velocities decreased. After the release of CSO, CSP immediately returned to baseline values, and the flow velocities correspondingly increased over the baseline values (hyperemic response). The decrease in ratios of flow velocities during CSO were unrelated to the duration of CSO, whereas hyperemic responses were positively correlated with the CSO duration. In the repetitive application of CSO (ICSO), inadequately short duration of release period decreased the net volume of coronary arterial flow significantly. Moreover, hyperemic responses were abolished by maximal coronary vasodilation with intravenous adenosine, augmented by combination with coronary sinus retroperfusion and reduced by coronary arterial ischemia. These findings indicate the presence of a compensatory regulating mechanism in the coronary circulation during ICSO. We should attach much importance to this mechanism for the effectiveness of ICSO. To be accurate, the changes in coronary arterial flow as well as CSP dynamics should be considered when choosing adequate occlusion-release intervals of ICSO.