Itzhak Weinberger

Plasma viscosity in ischemic heart disease

Plasma viscosity was measured by the capillary method in 108 patients with ischemic heart disease. The highest value of plasma viscosity was found in 11 patients with severe unstable angina (1.66 +/- 0.068), while in 18 patients with less severe unstable angina plasma viscosity was lower (1.61 +/- 0.056; p less than 0.025). In 43 patients with acute myocardial infarction plasma viscosity was 1.53 +/- 0.10, significantly lower than in the two groups with unstable angina (p less than 0.005). In 36 patients with stable angina plasma viscosity was 1.42 +/- 0.089, similar to that found in 100 normal subjects. Plasma viscosity did not increase in 30 ischemic heart disease patients during exercise-induced myocardial ischemia. It is suggested that the elevated plasma viscosity in unstable angina demonstrated in this study compromises the oxygen delivery to the myocardium and coronary blood flow and therefore may possibly be a factor in the pathophysiology of this syndrome.

Circulating Aggregated Platelets in Coronary Artery Disease

Circulating aggregated platelets were assessed in 30 patients with stable angina, 22 with unstable angina and 50 with acute myocardial infarction (AMI). Fifty healthy volunteers and 20 noncardiac patients served as controls. One milliliter of venous blood was separated into 2 solutions: 1 composed of ethylenediamine tetraacetic acid (EDTA) and formalin containing reversible and aggregates and 1 composed of EDTA alone containing irreversible aggregates only. By direct microscopic readings the percentage of platelets forming aggregates/1,000 counted platelets was determined in the 2 solutions. The number of reversibly aggregated platelets was estimated by subtracting the percentage of aggregated platelets in the second solution from that in the first solution. In patients with stable angina the percentage of aggregated platelets was higher than in control subjects (15 +/- 4% vs 7 +/- 2%, p less than 0.001). Most aggregated platelets (72% and 76%, respectively) were irreversibly aggregated. In the unstable angina group the percentage of aggregated platelets was similar to that of the AMI group (24 +/- 13% and 24 +/- 10%) and significantly higher than in the stable angina group. Only 11% and 17% of aggregated platelets in patients with stable angina and AMI were irreversibly aggregated and 89% and 83% of them were reversibly aggregated. Participation of platelets in the pathogenesis of unstable angina and AMI may be related to the early reversible phase of platelet activation.

Elevation of serum lactic dehydrogenase levels as an early marker of occult malignant lymphoma.

Elevated serum lactic dehydrogenase (LDH) levels, 595 to 615 μm/ml (normal < 225 μm/ml) with predominance of LDH isoenzymes 2 and 3 was the early and only sign of occult malignant lymphoma in three patients. In the first patient, overt lymphoma appeared clinically only 2 months after the finding of elevated serum LDH levels, whereas in the other two asymptomatic patients, pathologic LDH levels were the only clues to the need for further diagnostic investigation. It is concluded that LDH may have a diagnostic value in the preclinical stage of malignant lymphoma. Thus, a patient with no apparent cause for elevated serum LDH levels warrants a thorough work‐up including abdominal CT scan and even explorative laparotomy.

Acute Transmural Myocardial Infarction in Elderly Patients Hospitalized in the Coronary Care Unit Versus the General Medical Ward

The hospital records of 126 patients over 75 years of age with transmural myocardial infarction initially treated in the coronary care unit were compared with a concurrent similar group of 94 patients admitted directly to the general medical wards. The in‐hospital mortality rate for both groups together was 40%. The mortality rate within the coronary care unit was 24% as compared with 46% in the ward group (P < 0.005). However, the mortality rate for the coronary care unit group as a whole (including those patients later transferred to the general ward) was 35 versus 46% in the ward group. Congestive heart failure and cardiogenic shock were the most frequent complications in both groups (47 and 30%, respectively), and they were the main cause of death. Patients with these complications were less likely to be successfully resuscitated, even in the coronary care unit. The overall incidence of serious ventricular arrhythmias and complete heart block was similar to that reported for younger patients. Eleven patients in the coronary care unit group were successfully resuscitated from these arrhythmias and eight survived to be discharged from hospital. In contrast, only two patients in the ward group were successfully resuscitated and eight (9%) patients died suddenly and the fatal event could not be diagnosed. We concluded that elderly patients with an acute myocardial infarction can benefit from early admission to a coronary care unit. J Am Geriatr Soc 35:915–919, 1987

Circulating Platelet Aggregate Size in Ischemic Heart Disease

Platelet aggregate size was measured in 178 patients with ischemic heart disease, among whom 56 had stable angina, 42 suffered from unstable angina, and 80 had had uncomplicated acute myocardial infarction. A group of 50 healthy volunteers and 20 hospitalized noncardiac patients served as controls. Venous blood (0.5 cc) was introduced into a solution containing 11.7 mM EDTA and 1.0 g formaldehyde. Platelet aggregate size was determined by microscopic reading as the number of platelets forming aggregates (per 1000 counted platelets) divided by the number of aggregates. Mean aggregate size was found not significantly different in both control groups, as well as in patients with stable angina and acute myocardial infarction (2.21±0.36 platelets, 2.20±0.58 platelets, 2.28±0.19 platelets, 2.76±1.07 platelets, respectively, p=NS). The highest value was found in the unstable angina group: 4.00±1.40 platelets (p < 0.001 vs other studied groups). Platelet aggregate size was found not to be related to sex, age, medication, or coronary risk factors. Unstable angina may thus be a unique entity in ischemic heart disease concerning its platelet behavior, demonstrated in this study by the increased size of peripheral platelet aggregates, which may have pathogenetic, diagnostic, and eventual therapeutic implications.

Room temperature ADP induced first stage hyperaggregation of human blood platelets: a previously undescribed phenomenon and its relationship to spontaneous cold induced platelet aggregation

ADP induced human platelet aggregation was shown to be accentuated when tested at 20‐30°C as increased sensitivity and as a greater change of optical density although second stage aggregation and the release reaction did not occur. This previously undescribed phenomenon is defined as room temperature ADP induced first stage hyperaggregation. Aggregation, which occurs under the above mentioned conditions with a quantity of ADP insufficient to maintain the aggregation (usually less than 1 5 μm), is reversible when the temperature is raised to 3 7°C. After rewarming to these temperatures, second stage aggregation appeared in the presence of larger quantities of ADP (usually more than 2 μm) and could be blocked by aspirin. The absence of the release reaction was demonstrated with a lumi‐aggregometer. Spontaneous cold induced platelet aggregation seen after chilling platelets to 0‐4°C is shown to be a distinct phenomenon.

Big platelets in hyperlipidemic patients.

Both “big” platelets and hyperlipidemia are associated with increased coronary risk. This study was undertaken to search for a possible effect of various hypolipidemic drugs on big platelets. The percentage of big platelets, assessed microscopically, was measured in 66 patients who had hyperlipidemia of various types. Twenty‐seven patients with hypertriglyceridemia were randomly selected to receive either fish oil or placebo in a crossover study. Another group of 39 patients with hypercholesterolemia, among them 13 with heterozygous familial hypercholesterolemia (FH), received lovastatin. The pretreatment level of big platelets was elevated, and similar in all groups: 23.3 ± 12% versus 22 ± 9%, in the fish oil versus placebo group, 19.1 ± 6.3% versus 24 ± 11% in the FH versus non‐FH primary hypercholesterolemia group (reference value, 6.8 ± 3.5%). After treatment, despite the improvement in lipoprotein profile, the percentage of big platelets did not change. The relationship between lipid reduction and big platelets is thus questionable, and necessitates further study.

The Effect of Rapid Digitalization on Ventricular Function in Patients With Congestive Heart Failure

Cardiac glycosides have been used in the treatment of cardiac failure for more than 200 years. Digitalis and its analogues have been shown to increase myocardial contractility and to decrease left ventricular end‐diastolic pressure and volume, while causing no essential change in aortic pressure and a variable decrease in heart rate.1–2 However, several reports3–8 have questioned the use of digitalis in patients with ventricular dysfunction, particularly in view of the newer modes of therapy.