Short-term synchronized retroperfusion before reperfusion reduces infarct size after prolonged ischemia in dogs.

Background: Previous studies have demonstrated that synchronized coronary venous retroperfusion (SRP) can restore blood flow to the ischemic myocardium, resulting in infarct size reduction and improvement of the left ventricular function. Despite the nutritive blood flow achieved by SRP being relatively limited, SRP has been shown to improve washout of by-products from the ischemic myocardium. The aim of this study was to investigate whether short-term SRP immediately prior to reperfusion would attenuate the deteriorative phenomena following reperfusion.

Local beta-adrenergic blockade does not reduce infarct size after coronary occlusion and reperfusion: a study of coronary venous retroinfusion of metoprolol.

Previous studies have demonstrated pronounced ischemic zone myocardial concentrations of metoprolol following coronary venous retroinfusion in pigs with coronary artery ligation. The effect of coronary venous retroinfusion of metroprolol on myocardial infarct size was studied in 16 pentobarbital-anesthetized open-chest pigs undergoing 60-minute occlusion of the left anterior descending coronary artery followed by 3 hours of reperfusion. Pigs in the experimental group (n = 8) were given 0.

Preservation of regional myocardial ultrasonic backscatter and systolic function during brief periods of ischemia by synchronized coronary venous retroperfusion.

This study examines the effects of brief periods of ischemia on average and cardiac cycle-dependent variation of regional ultrasonic backscatter paralleled with changes in regional myocardial contraction, and to what extent these changes could be reversed by synchronized coronary venous retroperfusion. In five closed-chest dogs, the left anterior descending coronary artery was occluded on four occasions for a 2-minute period and retroperfusion was applied randomly to two of the coronary occlusions. Complete functional recovery was allowed between the occlusions.

Retrograde coronary venous administration of recombinant tissue-type plasminogen activator: a unique and effective approach to coronary artery thrombolysis.

Recent studies of interventional therapy by way of the coronary venous system have demonstrated that it can protect acutely ischemic myocardium. To evaluate the efficacy of coronary venous retroinfusion compared with systemic intravenous administration of recombinant tissue-type plasminogen activator (rt-PA), 14 dogs were studied with a copper coil-induced thrombus in the left anterior descending coronary artery. The rt-PA (24,000 fluorescence units/kg) was administered continuously, either intravenously (n = 8) or retrogradely (n = 6), for 30 min beginning 60 min after coronary occlusion.

Coronary venous retroinfusion of deferoxamine reduces infarct size in pigs.

The efficacy of coronary venous retroinfusion of the iron chelator deferoxamine was studied in 24 pentobarbital-anesthetized open chest pigs with a 60 min occlusion of the left anterior descending coronary artery followed by 3 h of reperfusion. Eight retrogradely treated pigs were given 10 mg/kg body weight of deferoxamine by way of the anterior interventricular vein and eight systemically treated pigs received the same doses of deferoxamine intravenously. Drug infusions lasted for 5 min, beginning 15 min before reperfusion.

Percutaneous cooling of ischemic myocardium by hypothermic retroperfusion of autologous arterial blood: effects on regional myocardial temperature distribution and infarct size.

The effects of synchronized coronary venous retroperfusion of cooled autologous arterial blood on regional myocardial temperature distribution and infarct size were studied in open chest dogs with 3.5 h of left anterior descending coronary artery occlusion. After 30 min of occlusion, the dogs were randomly assigned to one of three groups: 1) untreated control group (n = 5), 2) normothermic retroperfusion group (infusion temperature 32 degrees C) (n = 7), and 3) hypothermic retroperfusion group (infusion temperature 15 degrees C) (n = 7).

Coronary venous retroperfusion support during high risk angioplasty in patients with unstable angina: preliminary experience.

Synchronized coronary venous retroperfusion was used during coronary balloon angioplasty to support the ischemic myocardium of 20 patients with unstable angina and anatomy at high risk of a coronary event. Hemodynamics and left ventricular function were the major end points of the study. Coronary venous catheterization and retroperfusion were successfully performed in 15 patients.

Reversal of chronic regional myocardial dysfunction (hibernating myocardium) by synchronized diastolic coronary venous retroperfusion during coronary angioplasty.

A 62 year old man with previous myocardial infarction, an occluded right coronary artery and a 90% stenosis of the left anterior descending coronary artery underwent angioplasty with the support of coronary venous retroperfusion of arterial blood during the procedure. In two of four angioplasty balloon dilations of the left anterior descending coronary artery, synchronized diastolic retroperfusion of the coronary veins with arterial blood was applied to protect the severely dysfunctioning myocardium from additional ischemia. Two-dimensional echocardiography was used to monitor and quantitate alterations in left ventricular function.

Sequential noninvasive assessment of left ventricular size, regional wall thickness and function during 3 hours of coronary artery occlusion and reperfusion: differential effects of reflow in dogs with small vs large areas at risk.

1. The present study was undertaken to determine noninvasively the sequential changes in left ventricular (LV) size, wall thickness and regional contractile function occurring during 3 h of proximal left anterior descending coronary artery occlusion (CAO), and their modification by reperfusion (REP) over a 7-day period. 2.

Post-reperfusion function evaluated using two-dimensional echocardiography in dog: systolic/diastolic function vs percent necrosis.

Two-dimensional echocardiography (2DE) was performed in nine dogs with three hour proximal occlusion of the left anterior descending coronary artery and seven day reperfusion for sequentially mapping systolic functions (Seg-FAC%: percent segmental fractional area change) and diastolic functions (Seg-VLAC: mean velocity of segmental luminal area change) of eight segments in a mid-papillary left ventricular short-axis cross-section. The corresponding segment functions on 2DE to the most profoundly affected segment were evaluated by triphenyl-tetrazolium-chloride staining seven days post reperfusion, and categorized in two groups in terms percent mural necrosis (N%): N% greater than or equal to 40% in group A and N% less than 40% in group B, respectively. Seg-FAC% showed a significant difference between the two groups seven days post reperfusion (13.

Complete and delayed reversal of a large dyskinetic area with early spontaneous reperfusion during evolving myocardial infarction.

Sequential angiographic studies have shown that spontaneous reperfusion occurs in approximately 30 to 40% of patients during evolving myocardial infarction. However, it is difficult to establish the effects of spontaneous reperfusion on left ventricular function. We report the case of a 65 year old woman with clinical features of acute myocardial infarction with early spontaneous reperfusion and complete recovery of ventricular function 1 year later.

Early differentiation of infarcted and noninfarcted reperfused myocardium in dogs by quantitative analysis of regional myocardial echo amplitudes.

This study tests the hypothesis that ischemic but viable reperfused myocardium can be differentiated from infarcted reperfused myocardium by regional analysis of myocardial echo amplitudes. In eight closed-chest, anesthetized dogs, the left anterior descending coronary artery was occluded for 3 hours, followed by 1 hour of reperfusion, and sacrifice. Infarct size was measured by the triphenyl tetrazolium chloride technique in a 1-cm-thick mid-left ventricular transverse slice, and matched with a corresponding end-diastolic two-dimensional echo short-axis cross-section.

Effects of pressure-controlled intermittent coronary sinus occlusion on regional ischemic myocardial function.

Pressure-controlled intermittent coronary sinus occlusion has been reported to reduce infarct size in dogs with coronary artery occlusion, possibly because of increased ischemic zone perfusion and washout of toxic metabolites. The influence of this intervention on regional myocardial function was investigated in open and closed chest dogs. In six open chest dogs with severe stenosis of the left anterior descending coronary artery and subsequent total occlusion, a 10 minute application of intermittent coronary sinus occlusion increased ischemic myocardial segment shortening from 5.

Retrograde coronary venous contrast echocardiography: assessment of shunting and delineation of regional myocardium in the normal and ischemic canine heart.

Coronary venous injections of sonicated Renografin-76 were performed in seven closed chest dogs during two-dimensional echocardiography to study the ability of this new technique to opacify regional myocardium before and after occlusion of the left anterior descending coronary artery. The balloon of a 4F double lumen catheter was inflated in the great cardiac vein for each contrast injection to prevent backflow through the coronary sinus into the right atrium. Retrograde injections before coronary artery occlusion generally resulted in patchy myocardial contrast uptake.

Increased regional end-diastolic wall thickness early after reperfusion: a sign of irreversibly damaged myocardium.

Two-dimensional echocardiographic measurements of regional left ventricular end-diastolic wall thickness and systolic wall thickening were studied during coronary artery occlusion and early after reperfusion and compared with measurements of regional myocardial infarct size. In 25 closed chest anesthetized dogs with left anterior descending coronary artery occlusion followed by reperfusion, the occlusion period was 3 minutes in group I (n = 4), 20 minutes in group II (n = 4), 60 minutes in group III (n = 5) and 180 minutes in group IV (n = 12). Infarct size in groups III and IV was quantitated using the triphenyltetrazolium chloride technique.

Two-dimensional echocardiographic contrast assessment of pacing-induced mitral regurgitation: relation to altered regional left ventricular function.

Two-dimensional echocardiography during agitated saline contrast injections into the left ventricle was applied in eight closed chest dogs to examine the degree of mitral valve regurgitation encountered with pacing from two sites: 1) at the right ventricular apex and 2) within the coronary sinus at the base of the left ventricle. Pacing was at a rate of 10 beats/min above the sinus rate, and ranged from 60 to 120 beats/min. Hemodynamic variables were monitored, and data on global and regional left ventricular function were derived from a series of short- and long-axis cross-sectional echographic images.

Effects of late coronary artery reperfusion after myocardial necrosis is complete.

Early reperfusion salvages reversibly injured ischemic myocardium. Late reperfusion, after necrosis is complete, could be beneficial by accelerating healing, or the hemorrhage and contraction-band necrosis associated with reperfusion could impair healing. In closed-chest anesthetized dogs the left anterior descending coronary artery was occluded with a balloon-tipped catheter for either 1 day followed by reperfusion for 6 days (n = 9) or for 7 days without reperfusion (n = 9).