High-dose nitrates in the immediate management of unstable angina: optimal dosage, route of administration, and therapeutic goals

Nitrates are commonly used for rapid relief of ischemia in the initial management of unstable angina. However, their optimal dosage, route of administration, and therapeutic goals have not been fully established. This study was conducted to determine the optimal dosage and mode of administration (intravenous bolus versus sublingual spray) of nitrates and the therapeutic goals of their use in the immediate management of unstable angina. In a single-center prospective trial, 72 consecutive patients with unstable angina accompanied by typical ST-segment depression on electrocardiogram were randomly assigned to receive isosorbide dinitrate either as repeated intravenous boluses or as sublingual sprays while being delivered to the hospital by a mobile intensive care unit. Optimal nitrate dosage was tailored to pain relief while monitoring mean blood pressure reduction to an optimal range (5% to 20%) without dosage restriction. The mean nitrate dosage needed for ischemia control during the first hour of treatment was 7.8 +/- 3.8 mg. Optimal blood pressure reduction was achieved by significantly more intravenously treated patients than sublingually treated patients (68% v 41%, P = .037). Intravenously treated patients also experienced a more pronounced therapeutic effect, as assessed by reduction in chest pain score (67% v 39%, P = .0004) and decrease in ST-segment depressions (57% v 27%, P = .004). These results show that higher doses of nitrates than previously recommended are required for ischemia control during the initial management of unstable angina. The use of repeated intravenous boluses is safe and more easily controlled and, therefore, more efficacious than sublingual sprays in inducing the maximal anti-ischemic effect while avoiding significant hypotension.

Continuous rt-PA infusion as a salvage strategy to maintain patency of the infarct artery; safety of high cumulative dose and subsequent emergency coronary artery angioplasty and bypass surgery

Acute re-occlusion of an infarct artery reperfusion attained by thrombolytic therapy may be treated by emergency coronary angioplasty or bypass surgery. Repeated infusion of a thrombolytic agent is an additional treatment strategy. Three patients with reinfarctions that occurred very early after successful reperfusion were treated with continuous infusion of recombinant tissue-type plasminogen activator (rt-PA). These patients received a rt-PA dose of 300-360 mg while they awaited emergency mechanical revascularization procedures. Two patients had coronary angioplasty immediately after receiving repeated infusions of rt-PA and one underwent coronary bypass surgery while receiving a third rt-PA infusion. There were no bleeding complications in the 2 patients who underwent coronary angioplasty, and no excessive bleeding in the patient who received coronary bypass surgery. Thus, repeated continuous rt-PA infusions can be used to maintain the patency of recurrently occluding infarct arteries until definitive mechanical revascularization can be performed.

Use of asbestos in the Israeli Defense Forces

The Israeli Defense Forces (IDF) have adopted the current standards for asbestos in the workplace (1 fiber/ml). Although average daily exposure to asbestos is relatively limited, nevertheless, the army personnel concerned are defined as "asbestos workers." Four main areas of asbestos use were monitored, and medical examinations of susceptible personnel were performed. Recommendations were suggested for improving conditions. The IDF is now in the process of eliminating the use of materials containing asbestos, with the aim of eliminating asbestos use in the IDF within a three-to five-year period.

Unexpected cardiac pathology in pregnant women treated with beta-adrenergic agents (ritodrine)

Premature uterine contractions were treated by intravenous beta-mimetics in 190 patients during a 2-year period. History and physical examination were directed toward identification of patients with cardiac problems. Unexpected cardiac pathology was discovered in 14 patients, all of whom exhibited severe and continuous nausea, retrosternal pain, or dyspnea during beta-mimetic administration. Treatment was immediately discontinued in the presence of S-T depression, supraventricular tachycardia, nonspecific T wave changes, and sinus tachycardia with right axis deviation. Further investigation revealed obstructive cardiac myopathy in one case and atrial septal defect in another. Such changes might be identified earlier by more extensive screening procedures (such as electrocardiogram) before drug administration. Administration of beta-mimetic agents may uncover previously unexpected cardiac pathology. Continuation of ritodrine in such cases is contraindicated and potentially hazardous.