Objective Guidelines generally recommend oral anticoagulation to be considered the first 3 months after mitral valve repair based on small studies and consensus. However, in several studies no benefit of anticoagulation has been found.

Methods From the national registries we identified all Danish patients who underwent mitral valve repair during the period between 1997 and 2012. Medication, hospitalisation and mortality data were studied. The association of use of vitamin K antagonists (VKAs) at discharge and risk of stroke/death was evaluated by means of Cox regression, landmark analyses and propensity matched models.

Results 2188 patients without prior VKA use, stroke or death day 7 after discharge were included and median follow-up was 4.9 years (0–13.7). 859 (39%) were discharged on VKAs and 523 (24%) experienced death or stroke, 60 of these occurred within the first 3 months and 24 between 3 and 6 months. Compared with patients without post-discharge VKA, patients on VKA had a lower risk of death/stroke at 3 months (HR=0.28, CI (0.13 to 0.62), p=0.002) and in the time period from 3 to 6 months (HR=0.85, CI (0.35 to 2.07), p=0.72). Risk of significant bleeding complications within 3 months were comparable in the two groups with 23 (2%) among patients without VKA and 6 (1%) among VKA-treated.

Conclusion VKA treatment after mitral valve repair is associated with a markedly lower risk of adverse events as stroke or death without excess major bleeding risk during the first 3 months following surgery.