For patients on vitamin K antagonists (VKAs) who require surgery or invasive procedures, there is a need to balance the risk of bleeding during the procedure against the risk of an atherothrombotic event if therapy is interrupted. It has been suggested that it may be possible to safely perform some procedures, such as coronary angiography with or without percutaneous coronary intervention (PCI), without interruption of VKAs.

This systematic review and meta-analysis compared the safety of uninterrupted anticoagulation (U-VKA) in this setting with interrupted anticoagulation (I-VKA), with or without bridging with low-molecular-weight heparin.

Researchers identified 8 studies for the review, most of which were of moderate to very low quality. Six studies included patients who had PCI, whereas two reported only patients undergoing angiography. Four studies compared U-VKA with I-VKA with or without heparin bridging, and a fifth had a control group of non-anticoagulated patients. The patient population was similar across studies and consisted of elderly patients in which AF was the most common indication (69.6% of patients); other indications were a mechanical heart valve (7.1%), prior stroke (8.1%), and venous thromboembolism (4.9%). The mean INR on the day of the procedure in the U-VKA groups ranged from 1.99 to 2.5, and that in the I-VKA groups was between 1.5 and 1.9. Use of antiplatelet drugs varied widely across studies.

U-VKA appeared to confer approximately one-half the risk (odds ratio, 0.43; 95% CI, 0.26-0.73) of experiencing an access site bleeding complication within 1 week of the procedure compared with a strategy of I-VKA. This strategy was also associated with a pooled access site bleeding complication rate of 4.0% (95% CI, 3.0-7.0), and although high heterogeneity precluded pooling of such a rate in the I-VKA group, these rates ranged from 2% to 14%. The only atherothrombotic events occurred in one study where there was one stroke in the U-VKA group and two strokes in the I-VKA group.

The researchers conclude “although it appears that coronary angiography with or without PCI can be safely performed without interrupting VKA, the low methodological quality of existing studies precludes any definitive conclusions. Randomised trials assessing different anticoagulation strategies are needed to establish evidence-based practice guidelines in this setting.”

An accompanying editorial notes that in the absence of large RCTs, “the cornerstone of safely managing anticoagulated patients through procedures such as PCI will be to tailor therapy to the needs of individual patients, based on their relative risks of thromboembolism and bleeding.”