Paul J. LaRaia

Role of the Coronary Collateral Circulation in the Preservation of Left Ventricular Function

An angiographic assessment of the coronary arteries, the presence and quality of arterial collateralization and segmental left ventricular (LV) wall motion indicated that (a) in the presence of total or subtotal obstruction of a coronary artery, there was a significantly higher incidence of normal motion (p less than 0.001) if the segment of LV wall was supplied by good rather than poor collaterals, and (b) normal wall motion with good arterial collateralization was not associated with abnormal Q waves. It is concluded that a positive correlation exists between the quality of collateral filling and the preservation of LV wall motion in the area supplied.

Medically refractory unstable angina pectoris. I. Long-term follow-up of patients undergoing intraaortic balloon counterpulsation and operation.

Of 82 patients with medically refractory unstable angina pectoris seen between October 1972 and January 1978, 60 patients underwent a combination of intraaortic balloon pump counterpulsation, cardiac catheterization and coronary revascularization. Most patients had atherosclerotic involvement of the vessels of the anterior left ventricular wall, 48 patients (80 percent) had abnormalities of left ventricular wall contraction and 22 patients (36 percent) had evidence of acute myocardial injury. One operative and one late death occurred. The perioperative infarction rate was 5 percent. Survivors, followed up for 3 to 63 months (mean 31 months), have done remarkably well; 77 percent are considered employable,and more than 90 percent are in functional class I or II.

Treatment of preinfarction angina with intraaortic balloon counterpulsation and surgery

Abstract Sixteen patients with preinfarction angina unresponsive to medical therapy were treated by Counterpulsation with the intraaortic balloon pump. Chest pain and electrocardiographic changes were abolished or significantly decreased in all but one patient. Counterpulsation reduced peak systolic blood pressure, but had little effect on pulmonary capillary wedge pressure or cardiac output. Coronary anatomy was then defined by coronary angiography. Significant obstructive atherosclerosis of the main left or left anterior descending coronary artery was present in all but one patient. All patients underwent coronary revascularization by saphenous vein aortocoronary bypass graft. Fifteen of 16 patients survived the operation. All survivors are clinically improved, and 13 are completely asymptomatic from 1 to 20 months postoperatively.

Biochemical studies on the regulation of myocardial contractility.

NEW information regarding the chemical basis for adjustments in cardiac performance has recently come to light. Short-term augmentation of contractility may be mediated by cyclic AMP through a mechanism that involves membrane phosphorylation. In addition, studies of biochemical changes that occur in cardiac hypertrophy indicate that contractile proteins are rapidly replaced in response to work overload. It has also been suggested that an abnormal myosin species underlies the defective performance of hypertrophied and failing hearts; no structural abnormality in myosin or other contractile proteins has been identified, however. Before the evidence of multiple biochemical defects in these hearts is discussed, .xa0.xa0.

Differential effects of sodium meglumine calcium metrizoate on the inotropic state of normal and ischemic myocardium.

Sodium meglumine calcium metrizoate was injected into isolated blood-perfused canine hearts to evaluate the effect of contrast agents containing calcium on normal and ischemic myocardium. Under normal perfusion pressure and mild ischemia, this contrast agent produced a positive inotropic effect, but during profound ischemia, this positive effect was followed by a period of myocardial depression. These findings indicate that the addition of an inotropic agent to contrast medium can produce a paradoxical depressant effect which can be deleterious to the ischemic myocardium.

Myocardial protection by coronary washout during global ischemic cardiac arrest

The effect of intermittent coronary washout (WO) during global ischemic cardiac arrest (ICA) was evaluated in isolated blood perfused dog hearts undergoing 90 min normothermic ICA and 90 min reperfusion. WO consisted of infusion of 100 ml normothermic dog plasma at 100 mm Hg every 10 min during ICA. Systolic and diastolic pressures were measured at constant volume with a left ventricular balloon. Coronary blood flow (CBF) was measured, and transmyocardial oxygen, lactate, and glucose differences were calculated. Adenosine triphosphate (ATP), creatine phosphate (CP), calcium (Ca2+), glycogen, and water content were measured from left ventricular biopsies. During 90 min of WO, hearts extracted glucose (15 ± 4 mg/g dry wt LV) and lost lactate (90 ± 5 μmole/g dry wt LV). ATP and CP were significantly depressed at arrest in both groups although WO resulted in significantly higher levels of ATP and CP. CP returned to control levels at 90 min reperfusion in the WO group but remained depressed in the ICA group. Calcium accumulation was greater in hearts with ICA. With reperfusion, both ICA and WO groups demonstrated early hyperemia and rapid lactate washout. There were no differences in total CBF, AVO2, MOV2, and myocardial glycogen or water content. Systolic performance was equally depressed in both groups at 90 min of reperfusion. Diastolic compliance, while still impaired, was better preserved in WO when measured in the arrested heart at 90 min ICA (P < 0.01) and in the contracting heart after 90 min reperfusion (P < 0.02). Normothermic coronary washout during 90 min of normothermic ischemic arrest without cardioplegic agents produces improved ventricular compliance and energy metabolism, and reduces myocardial calcium accumulation.