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Synchronized coronary venous retroperfusion was applied and studied in 16 patients undergoing percutaneous transluminal coronary angioplasty (PTCA) balloon dilatation of proximal left anterior descending (LAD) coronary artery stenosis. The rationale for using retroperfusion support during the PTCA-induced coronary artery occlusions was to ameliorate or prevent myocardial ischemia and possibly facilitate extension of the PTCA balloon-inflation period. After therapeutic PTCA treatment, which successfully dilated the culprit coronary artery in all 16 patients, and a 5-minute recovery period, a single retroperfusion-treated LAD occlusion (101 +/- 36 seconds) was compared with equivalent untreated control LAD occlusions (86 +/- 24 seconds) before and after the retroperfusion-supported balloon occlusion. Observations and measurements encompassed 1) ease and time of coronary sinus catheterization, 2) incidence of anginal pain during LAD occlusion, 3) electrocardiographic signs of myocardial ischemia, and 4) two-dimensional echocardiographic indexes of global left ventricular function. The coronary sinus was successfully catheterized within 139 +/- 140 seconds, and in 12 of the 16 patients, the tip of the special autoinflatable retroperfusion balloon catheter could be placed in the desired location of the great cardiac vein. The retroperfusion protocol interfered minimally with the PTCA procedure, and application of the support system had no deleterious effects. As compared with the pain reported 23 (72%) times during the 32 control LAD occlusions, only five (31%) of the patients indicated pain or discomfort during the retroperfused occlusions. Treated occlusions exhibited delayed or significantly lower electrocardiographic ST segment elevations (sum, 10.4 +/- 7.8 mm) as compared with the controls (sum, 16.2 +/- 7.9 mm and 18.8 +/- 10.6 mm; both p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary retroperfusion with the object of delivering oxygenated blood to the ischemic myocardium might be defined as the process of withdrawing blood from a systemic artery and reinjecting it into the coronary sinus. A diastolic synchronized retroperfusion catheter-pump system is presented and feasibility of achieving retrograde infusion of arterial blood was tested. An autoinflatable bladder catheter was specially designed to compartmentalize the coronary sinus at onset of diastole and insure unidirectional retrograde infusion of arterial blood. Bladder deflation at onset of systole allowed coronary venous drainage. Actuation of the retroperfusion bladder catheter was obtained from an electropneumatic console triggered by the electrocardiogram. In vitro and animal studies indicate that this system converted the natural (steady) arteriovenous shunt flow into an artificially pulsed shunt flow, with maximal positive flow in diastole and trivial negative flow in systole but did not alter absolute magnitude of shunt flow. Thus, diastolic synchronized retroperfusion of arterial blood through the coronary sinus may provide temporary protection from acute myocardial ischemia.

To investigate whether addition of vasodilator drugs can increase the beneficial effects on the ischemic myocardium of diastolic synchronized retroperfusion (DSR), low doses of verapamil (2 micrograms/kg/min) or nitroglycerin (0.7 microgram/kg/min) were infused through DSR in open-chest dogs undergoing 180 minutes of proximal left anterior descending coronary artery occlusion. Verapamil-DSR (n = 6), nitroglycerin-DSR (n = 6) or DSR alone (n = 8, controls) were started 10 minutes after the onset of occlusion and maintained for 170 minutes. Regional myocardial blood flow (MBF) (microspheres) and left ventricular function (endocardial ultrasonic crystals) were simultaneously assessed in nonischemic and ischemic zones in the 3 groups, before and after 10 and 180 minutes of coronary occlusion. DSR alone significantly increased ischemic regional MBF, endocardial/epicardial flow ratio and endocardial segmental length shortening. Verapamil DSR increased both nonischemic and ischemic regional MBF but reduced the endocardial/epicardial flow ratio and worsened ischemic contractile function. Nitroglycerin DSR did not modify ischemic transmural flow compared with DSR alone, but abolished the beneficial endocardial/epicardial blood flow redistribution, resulting in no additional improvement of contractile function. Thus, ischemic MBF and function are not improved by addition of small amounts of verapamil or nitroglycerin to the arterial retroperfusate in this model of acute myocardial ischemia.

The effects of 170 minutes of diastolic synchronized retroperfusion of the coronary sinus with arterial blood during 180 minutes of coronary artery occlusion on regional myocardial contractility (ultrasonic crystals) and blood flow (microspheres) were investigated in open-chest dogs. These effects were compared with those of 180 minutes of coronary occlusion and those of 170 minutes of anterograde reperfusion after 10 minutes of coronary occlusion in separate groups of dogs. Retroperfusion was able to almost restore transmural blood flow in the moderately ischemic zones and to increase it back to 47% of its preocclusion value in the severely ischemic zones with, in both zones, a favorable redistribution of flow toward the endocardium. Simultaneously, retroperfusion significantly improved segment length shortening in the moderately ischemic zones and significantly reduced the extent of paradoxical bulging in the severely ischemic zones. These partial recoveries in regional contractility and blood flow during retroperfusion were intermediate between those induced by 170 minutes of anterograde reperfusion and those of 180 minutes of coronary artery occlusion. Thus, in the presence of coronary artery occlusion, retroperfusion appears to exert a beneficial effect by improving both regional perfusion and function in the ischemic zones and may be proposed as a medical circulatory support to the jeopardized myocardium.