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Following transradial coronary angiography, radial artery occlusion is more likely to occur in patients on chronic warfarin therapy but no parenteral anticoagulation compared with those receiving standard IV heparin alone, according to a study published online November 11, 2013, ahead of print in the American Journal of Cardiology. 

Drawing on registry data from 2 community hospitals, researchers led by Samir B. Pancholy, MD, of the Commonwealth Medical College (Scranton, PA), compared the incidence of radial occlusion after coronary artery angiography via transradial access among patients receiving warfarin (INR 2-4 on the day of the procedure; n = 83) or a standard IV bolus (50 IU/kg) of unfractionated heparin (n = 250). After sheath insertion, operators obtained hemostasis using the TR-band (Terumo Interventional Systems, Someret, NJ) and plethysmography guiding.

Both early (24 hours) and late (30 days) radial artery occlusion were more frequent among the warfarin patients (table 1).

Table 1. Radial Artery Occlusion: Warfarin vs. Heparin

Rates of patent hemostasis were similar between the warfarin and heparin groups (77% vs.74%; P = 0.44). Two patients in the warfarin group and 4 in the control group had EASYs grade 1 hematoma (P = 0.21). There were no cases of pseudoaneurysm, arteriovenous fistula, or larger hematomas, and all patients with radial occlusion remained asymptomatic.

Absence of Antiplatelet Activity a Possible Contributor

In an e-mail communication with TCTMD, Dr. Pancholy said he was initially surprised by the higher incidence of radial occlusion among warfarin patients “because we believed an anticoagulated state was protective for thrombosis in general.” But in hindsight, he added, antiplatelet therapy is likely more important in medium-sized arteries, such as the coronary and radial arteries, and warfarin has no antiplatelet activity while bolus heparin seems to have some antiplatelet effect. 

R. Lee Jobe, MD, of North Carolina Heart and Vascular (Raleigh, NC), called the occlusion rates alarmingly high in both groups, given that his institution aims to achieve a rate of less than 2%. In addition, access-site compression with the TR-band was maintained for 2 hours, suggesting that this could have contributed to the high occlusion rates, he noted.

Further, the presence of occlusion in spite of either form of anticoagulation “suggests a nonthrombotic mechanism may be playing an important role,” Dr. Jobe told TCTMD in an e-mail communication. He agreed that antiplatelet activity may indeed be more important in this setting, and suggested studying the use of local or systemic antiplatelet agents to try to reduce radial occlusion rates.

Dr. Pancholy and colleagues acknowledge that the retrospective design of the study limits its interpretation and a prospective, randomized trial is needed to confirm the finding. Moreover, they add, it is unknown whether the results are applicable to patients receiving novel oral anticoagulants.

Nonetheless, “based on our data, we recommend administering heparin to patients with an INR between 2 and 4 on warfarin undergoing transradial catheterization,” Dr. Pancholy said. “We have not observed a noticeable increase in bleeding risk [with this strategy].”

Study Details

Patients had an average age of 72 years, and about two-thirds were men. There were no differences between the groups with regard to diabetes, smoking status, BMI, or other baseline characteristics.

Pancholy SB, Ahmed I, Bertrand OF, et al. Frequency of radial artery occlusion after transradial access in patients receiving warfarin therapy and undergoing coronary angiography. Am J Cardiol. 2013;Epub ahead of print.

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