Comparison of High-Dose with Low-Dose Subcutaneous Heparin to Prevent Left Ventricular Mural Thrombosis in Patients with Acute Transmural Anterior Myocardial Infarction

Abstract

We performed a double-blind randomized trial comparing high doses of subcutaneous heparin (12,500 units every 12 hours) with low doses (5000 units every 12 hours) for 10 days in the prevention of left ventricular mural thrombosis in 221 patients with acute anterior myocardial infarction. Left ventricular mural thrombosis was observed by two-dimensional echocardiography on the 10th day after infarction in 10 of 95 patients (11 percent) in the high-dose group and in 28 of 88 patients (32 percent) in the low-dose group (P = 0.0004). One patient in the high-dose group and four in the low-dose group had nonhemorrhagic strokes (P = 0.17). One patient in the low-dose group had a fatal pulmonary embolism. There was no difference in the frequency of hemorrhagic complications, which occurred in six patients in the high-dose group and four in the low-dose group. The mean (+/- SEM) plasma heparin concentration was 0.18 +/- 0.017 U per milliliter in the high-dose group and 0.01 +/- 0.005 U per milliliter in the low-dose group (P less than 0.0001). In the high-dose group, the mean plasma heparin concentration was 0.10 +/- 0.029 U per milliliter among patients with abnormal two-dimensional echocardiograms, as compared with 0.19 +/- 0.019 U per milliliter among patients with normal echocardiograms (P = 0.01). We conclude that heparin administered subcutaneously in a dosage of 12,500 units every 12 hours to patients with acute anterior transmural myocardial infarction is more effective than a lower dosage (5000 units every 12 hours) in preventing left ventricular mural thrombosis.

Heparin Therapy in Pediatric Patients: A Prospective Cohort Study

“…Recent studies in adults with DVT have shown that achieving a therapeutic APTT early (within 48 h of initiating treatment) significantly reduces the rate of recurrence (30,(34)(35)(36)(37). Informal audits of heparin therapy in adult patients have shown that doseadjustment practices are often inadequate delaying the achievement of an APTT value above the minimum therapeutic level (20,38,39).…”

Problems In Laboratory Monitoring Of Heparin Dosage

“…In order to combat this problem, samples from heparinized patients can be collected into an anticoagulant cocktail that inhibits platelet release, thereby avoiding PF4-mediated neutralization of heparin. It has been demonstrated that collection of blood into a citrate, theophylline, adenosine, dypyridamole mixture (CTAD) can greatly reduce the neutralization of heparin activity in blood (Contant et al, 1983;Van den Besselaar et al, 1987). In the study of Van den Besselaar et al (1987), APTTs of blood samples collected into CTAD were associated with less than 11% shortening depending on APTT reagent, compared with a 15±29% shortening of citrated APTTs between 1 h and 5 h after collection.…”

A coupled chemo-fluidic computational model for thrombogenesis in infarcted left ventricles

“…The identification of high-risk patients and the pharmacological prevention of LVT formation are the key to preventing embolic events. Once an "at risk" patient is identified, treatment with heparin and then warfarin reduces the risk of LVT formation (43) and results in an 86% reduction in the rate of embolization (44). However effective, anticoagulation is not without risk.…”