Blood thinners increase perioperative complication risk

Use of warfarin or clopidogrel is associated with a significant increase in non-sight-threatening complications during cataract surgery, concluded a study published in the January issue of Eye.

Rob L. Johnston, of the Gloucestershire Eye Department, Cheltenham General Hospital, Gloucestershire Hospitals NHS Foundation Trust, Cheltenham, Gloucestershire, UK and colleagues remotely used the Cataract National Dataset to extract and analyse data on 48,862 operations for which other pharmaceutical information was available, and assessed how these drugs impacted complication rates. The operations assessed were conducted across eight National Health Service (NHS) centres between 2001 and 2006; 28.1% of the patients studied were taking aspirin, 5.1% were taking warfarin, 1.9% were taking clopidogrel and 1.0% were taking dipyridamole.

The data showed that 8.0% of clopidogrel users reported sharp needle or subtenon’s cannula local anaesthetic block. This compares with 6.2% of warfarin users and 4.3% of other patients. The incidence of sight-threatening complications, however, was similar across all groups. The incidence of subconjunctival haemorrhage was 4.4% for clopidogrel users, 3.7% for warfarin users and 1.7% of other patients. Posterior capsular rupture (PCR) incidence was 3.23% in clopidogrel users and 1.77% for other patients. Overall, 7.3% of clopidogrel users experienced a perioperative complication, compared with 4.4% of other patients.

The researchers concluded that use of either clopidogrel or warfarin increased the likelihood of sharp needle or subtenon’s cannula during cataract surgery, although the risk of sight-threatening or haemorrhagic complications was not increased.