Efficacy of a single dose intravenous heparin in reducing sheath-thrombus formation during diagnostic angiography: A randomized controlled trial

Abstract 

Background

Femoral arterial sheath thrombosis and distal embolization are well-recognized complications of cardiac catheterization but the occlusion is extremely rare. Heparinized saline flushes are used during diagnostic coronary angiography to prevent thrombus formation within the sheath lumen. However, the use of prophylactic intravenous heparin following the femoral arterial sheath insertion is controversial. The aim of this study is to evaluate the effectiveness of 2000 units of intravenous heparin bolus in comparison to a saline placebo on the thrombus formation within the arterial sheath during the diagnostic coronary angiography.

Methods

Eligible patients were randomized to receive either a study drug or placebo at the time of femoral sheath insertion. The sheath was aspirated and flushed for any presence of thrombus after each catheter exchange and at the end of the procedure. Five milliliters of blood were extracted and visualized on clean gauze followed by a saline flush. The primary end-point was the effectiveness of the study drug on reducing the incidence of sheath-thrombus formation.

Results

Three hundred and twenty patients were randomized into two arms. Three hundred and four patients were analyzed: 147 patients in heparin arm and 157 patients in placebo arm after exclusion of 13 patients in heparin arm and three in placebo arm because of incomplete reports. The baseline characteristics were similar and sheath-thrombi formation was observed in 20% of the total cohort.

Of the heparin arm, 12% (19 patients) developed sheath-thrombus formation, whereas 26% (42 patients) in the placebo arm, p-value=0.002. An adjusted logistic regression model showed that the only predictor for the sheath-thrombus formation was the study drug (i.e. heparin). The odds ratio of developing a thrombus in the control arm was 2.5 (95% CI: 1.4–4.5, p=0.003). There were no bleeding events observed.

Conclusion

The risk of thrombus formation is significant and intravenous heparin significantly reduced thrombus formation during diagnostic coronary angiography, with no excess bleeding events.

Keywords: Femoral arterial access, Thrombus formation, Cardiac catheterization, Heparin