Coronary perfusion catheter: Its effectiveness in an experimental model of acute coronary occlusion

The effectiveness of a coronary perfusion catheter was studied in an animal model of acute coronary occlusion. Systemic hemodynamic variables, regional myocardial blood flow (RMBF) in the subepicardium and subendocardium, and regional systolic function (systolic segmental shortening) of the area perfused by the circumflex coronary artery (CX) were measured in eight anesthetized dogs. After baseline measurements, the CX coronary artery was occluded with a silk snare and measurements were repeated after 5 minutes of ischemia (occlusion No. 1). The snare was released and 1 hour later the snare occlusion was repeated after placement of a perfusion catheter in the CX coronary artery. After 5 minutes, measurements were repeated (occlusion No. 2). To determine the long-term effectiveness of the catheter, hemodynamic variables and regional function measurements were then obtained every 15 minutes for a total of 60 minutes. During occlusion No. 1, RMBF decreased from 1.30 ± 0.20 to 0.41 ± 0.13 ml · min^-1 · gm^-1 (p < 0.01), and subendocardial RMBF decreased from 1.44 ± .24 to 0.34 ± 0.15 ml · min^-1 · gm^-1 (p < 0.01). After insertion of the perfusion catheter (occlusion No. 2), subepicardial RMBF was maintained at 0.97 ± 0.16 and subendocardial RMBF was maintained at 0.78 ± 0.13 ml · min^-1 · gm^-1; during occlusion No. 2 subepicardial RMBF was greater (p < 0.05) than occlusion No. 1 and was not different from baseline. The increase in subendocardial RMBF did not reach statistical significance compared with values during occlusion No. 1; the values were significantly lower than baseline (p < 0.05). Regional systolic function measured at the end of occlusion No. 1 revealed a marked dyskinesis pattern in the ischemic region and increased shortening in the control region. This type of response was not observed following occlusion No. 2, either short-term or during the 60-minute observation time. Our data show that in the setting of an acute coronary occlusion, a coronary perfusion catheter can help maintain coronary blood flow and preserve regional myocardial function.