Ethyl alcohol. Effects on coronary blood flow in man

Effect of alcohol intoxication on hemodynamic physiology and outcome in patients with traumatic cardiac tamponade

BACKGROUND

Alcohol intoxication has a detrimental effect on hypovolemic shock. Our aim, was to study its effects on "pure" cardiac tamponade (i.e., without hypovolemia) in patients with penetrating chest injuries.

METHODS

Thirty-five intoxicated and 15 nonintoxicated patients (blood alcohol > and < 17 mmol/L) were studied. Initial vital signs (trauma scores), special investigations (hematologic profiles, blood gases, glucose, lactate, and catecholamines), clinical progress (24- and 72-hour acute physiology and chronic health evaluation II scores) and outcome were compared.

RESULTS

Intoxicated patients were older (p = 0.02) and more tachypneic on admission (p = 0.006), but no other differences were noted. Mortality was proportional to the degree of shock and was greater in patients who had "front-room" thoracotomies (p < 0.001). Despite the higher percentage of intoxicated patients who were "lifeless" or "in extremis" on admission, they fared no worse than nonintoxicated patients.

CONCLUSION

Alcohol intoxication does not have an adverse affect on traumatic cardiac tamponade.

Stroke and alcohol intake in a hospital population. A case-control study

BACKGROUND AND PURPOSE

The aim of the study was to assess whether excessive alcohol intake is an independent risk factor for stroke.

METHODS

A case-control study was undertaken in 200 consecutive ischemic and hemorrhagic stroke patients and 372 age- and sex-matched control subjects (170 hospital-based and 202 community-based individuals). Data were collected through direct interview regarding demographics, risk factors for stroke, current daily alcohol consumption, and diagnosis of alcoholism. Blood was also taken to test the common biological markers of alcohol intake (erythrocyte mean cell volume, uric acid, aspartate aminotransferase, and gamma-glutamyl transferase).

RESULTS

After controlling for the most significant risk factors (antecedent strokes, hypertension, diabetes, smoking) and using hospital control subjects for reference, we determined the risk of stroke to be 2.2 (95% confidence interval [CI], 1.2 to 4.0) in moderate drinkers (men, < or = 60 g/d; women, < or = 40 g/d) and 2.9 (95% CI, 1.4 to 6.1) in heavy drinkers (men, > 60 g/d; women, > 40 g/d). The corresponding risk values obtained when we compared case subjects and external control subjects were 1.4 (95% CI, 0.8 to 2.7) and 3.0 (95% CI, 1.3 to 7.0). Even with some fluctuations across groups, the risk did not change significantly after subgroup analysis in men, patients with first-ever stroke, patients with ischemic stroke, and after exclusion of subjects with risk factors for stroke. Compared with hospital and external control subjects, stroke patients included a higher proportion of heavy drinkers (26.6% versus 20.6% versus 10.8%), alcoholics (14.6% versus 7.7% versus 2.5%), and cases with abnormal erythrocyte mean cell volume (63.0% versus 47.6% versus 34.2%) or gamma-glutamyl transferase (35.5% versus 32.4% versus 12.9%). Mean alcohol consumption was 42.2 g/d in the case subjects, 30.8 g/d in the hospital control subjects, and 23.2 g/d in the external control subjects.

CONCLUSIONS

The study indicates that alcohol can be considered an independent risk factor for stroke in Italy.

Alcohol and coronary artery disease

Alcohol affects the heart and circulation in several ways. Chronic alcohol consumption can be associated with a variety of cardiovascular disorders, ranging from hypertension and stroke to heart failure and sudden death. At the same time an inverse correlation has been found between moderate drinking and incidence of coronary artery disease, perhaps due to its favourable effects on lipoprotein levels. Reports on acute effects of alcohol on coronary circulation, which may be of great significance in patients with pre-existing heart disease, have been contradictory. However, clinical studies have demonstrated an adverse effect of acute alcohol intake in low to moderate doses on coronary supply-demand relation in patients with angina pectoris. Considering the overall health hazard of alcohol consumption, a recommendation that patients increase their alcohol intake or that they start to drink if they do not already would probably be unjustifiable.

Cerebrovascular disorders and alcohol intake: preliminary results of a case-control study

The role of alcohol as a risk factor for cerebral infarction and hemorrhage has been assesed in 200 middle-aged and elderly stroke patients and 200 controls matched for age, sex and hospital admission date. Computed tomographic brain scans were done in all but 10 of the stroke patients. Alcohol intake was reckoned on the 12 months preceding hospitalization and expressed in grams daily according to a standard nomogram. The Michigan Alcoholism Screening Test was used for the diagnosis of alcoholism. Cerebral infarction was present in 59% of the stroke patients and cerebral hemorrhage in 9%. The role of alcohol as risk factor for stroke proved to be small (Odds Ratio 1.86) and was practically lost after adjustment for the most common risk factors for cerebrovascular disorders (previous strokes, arterial hypertension, diabetes, obesity and hyperlipidemia). Our findings seem to suggest that alcohol is not an independent risk factor for stroke in the middle-aged and elderly. The data are, however, preliminary and are discussed in the light of methological problems.

Indirect assessment of acute effects of ethyl alcohol on coronary circulation in patients with chronic stable angina

Acute effects of ethyl alcohol on left ventricular performance, haemodynamic and electrocardiographic response to treadmill exercise test were studied in 20 patients with chronic stable angina. Following ingestion of 80 ml of whisky (43% ethyl alcohol by volume) the mean heart rate and rate-pressure product decreased significantly at the end of each stage of exercise compared to corresponding prealcohol values. There were also significant derangements in systolic time intervals parameters in the form of decrease in left ventricular ejection time I and increase in pre-ejection phase I and pre-ejection phase/left ventricular ejection time ratio after alcohol intake indicating a depression in left ventricular performance. However, following alcohol intake the mean exercise time (6.5 +/- 3.8 minutes) until onset of ischaemic ST segment depression decreased significantly (P less than 0.01) compared to the corresponding prealcohol exercise time (8.6 +/- 3.5 minutes). Interestingly, the mean rate-pressure product (an indicator of myocardial oxygen demand) at the onset of ischaemic ST segment depression was significantly less (P less than 0.01) when exercise test was done after alcohol intake compared to the corresponding pre-alcohol value. The data indicated that despite significant decrease in myocardial oxygen demand produced by alcohol intake, ST T changes developed early and at a lower rate-pressure product, indicating decreased blood flow to the ischaemic zones of the myocardium. This may be explained by the coronary steal effect produced by alcohol.

Epicardial coronary artery constriction with intravenous ethanol

Although in vitro studies have demonstrated ethanol-induced coronary artery constriction, in vivo reports suggest an ethanol-related coronary dilator effect with increases in coronary blood flow. The principal difference in these studies is the demonstration of epicardial coronary constriction with ethanol, while dilation is described only in resistance vessels. Clinical studies have noted evidence of myocardial ischemia following ethanol ingestion in patients with coronary artery disease, suggesting ethanol-related constriction of diseased epicardial coronary arteries. This study hypothesized that intravenous ethanol would constrict canine epicardial coronary arteries while producing arteriolar resistance vessel dilatation. Ten closed-chest mongrel dogs weighing 24 +/- 1 kg (mean +/- SEM) were given 8 g of ethanol intravenously over 30 min. Left anterior descending and circumflex proximal artery diameters were measured by quantitative coronary angiography; myocardial flow was measured by Xenon washout, and myocardial flow distribution was measured with radioactive microspheres. Baseline proximal left anterior descending and circumflex artery areas were 6.3 +/- 0.5 and 5.8 +/- 0.4 mm2, respectively. Up to 30% left anterior descending and circumflex proximal artery narrowing was noted at 60 and 90 min following ethanol infusion. The constriction was reversed with nitroglycerin. There was a decrease in left anterior descending artery flow but no change in circumflex artery flow at 60 min. Blood ethanol level varied from 520 micrograms/ml initially to 205 micrograms/ml 90 min after the infusion terminated (intoxication = 1500 micrograms/ml). These data suggest that ethanol has significant vasoconstrictor action in vivo on epicardial coronary arteries.

Alcohol and stroke

Alcohol might contribute to stroke in several ways: induction of cardiac arrhythmias and cardiac wall motion abnormalities which predispose to cerebral embolism, induction of hypertension, enhancement of platelet aggregation and activation of the clotting cascade, and reduction of cerebral blood flow by stimulation of cerebral vascular smooth muscle contraction or by altering cerebral metabolism. While these pathophysiological mechanisms have gained enthusiastic experimental and theoretical support, the findings are preliminary and will require further large-scale clinical and epidemiological analyses to substantiate their roles as causal factors or potentiators of stroke. Documentation of measurable platelet and coagulation cascade abnormalities reported in healthy volunteers who have ingested alcohol will need to be confirmed on a broader scale in stroke patients with recent ethanol consumption. The risk of stroke in those with alcohol-induced atrial fibrillation and cardiomyopathy must be ascertained for the general population. While the experimental evidence is exciting and provocative, epidemiological evidence also suggests a link between alcohol consumption and stroke. Regular alcohol ingestion is associated with hypertension, fatal and nonfatal intracranial hemorrhage, cerebral infarction, and increased risk of death from stroke. Recent, less stringently controlled studies suggest that alcohol consumption is a risk factor for cerebral infarction in young adults with occasional ethanol intoxication and middle-aged women and young men with occasional alcohol intoxication and regular heavy drinking. Alcohol may also be a risk factor for subarachnoid hemorrhage.

Long-term effects of cigarette smoking and moderate alcohol consumption on coronary artery diameter. Mechanisms of coronary artery disease independent of atherosclerosis or thrombosis?

Epidemiologic studies have shown that cigarette smoking (increased risk) and moderate alcohol consumption (decreased risk) have opposite effects in coronary artery disease. To investigate whether they act via the common mechanism of affecting the coronary diameter, 31 white men with arteriographically normal coronary arteries were evaluated. Histories of cigarette smoking (never smoked, exsmoker, or current smoker) and alcohol consumption (nonuser or low user versus moderate users with an average of one drink per day) were analyzed for an association with coronary diameters. Nonsmokers had larger left main and left anterior descending diameters than either exsmokers or current smokers (p = 0.0001 and 0.004). Moderate alcohol users had large left main and left anterior descending diameters than nondrinkers (p = 0.009 and 0.01). Neither association was removed after adjustment for the other risk factor. These data suggest that smoking and moderate alcohol use have significant, independent, and opposite effects on long-term coronary diameter. These effects may be important mechanisms through which these behaviors alter the risk of coronary artery disease.

Chronic alcohol abuse and high density lipoprotein cholesterol

The possible use of high density lipoprotein cholesterol (HDLC) as a marker of alcohol abuse was studied in 92 alcoholic patients entering an inpatient treatment program. The average HDLC levels of 68 male patients (66 +/- 23 mg/dl) and 24 female patients (83 +/- 18 mg/dl) were significantly higher than the values for the corresponding control groups of similar ages. Approximately 20% of the male patients had HDLC levels over the mean +/- 2 SD over the control groups. Following 2 wk of alcohol abstinence, the HDLC levels decreased to the control range. HDLC, as a measure of alcohol abuse, may be especially useful in combination with determination of gamma glutamyl transpeptidase (GGT), since these two tests singly or in combination were elevated in 65% of the male and 85% of the female patients.

Effects of phentolamine on coronary blood flow in patients with recent myocardial infarction

The myocardial clearance of rubidium may be obtained by praecordial counting after intravenous injection of Rb-minus 86 Cl. Eight patients with recent myocardial infarction had this determination performed before and after the infusion of 10 mg phentolamine at a rate of 0.3 mg/minute. The average predrug myocardial clearance of Rb was 89.3 plus or minus 29.9 ml/min per 100 g myocardium. After phentolamine, the average myocardial clearance rose to 117.3 plus or minus 33.3 ml/min per 100 g myocardium (P LESS THAN 0.01). An explanation for this findings is presented as well as its possible clinical applications.