Fibrinolysis in left-sided mechanical prosthetic valve thrombosis with high INR.

Background: A significant number of patients with prosthetic valve thrombosis have a prothrombin time international normalised ratio in the therapeutic range at presentation. Surgery may not be possible in many patients and traditionally a high international normalised ratio is considered a relative contraindication for fibrinolysis.

Methods: We conducted an observational study in patients with left-sided obstructive prosthetic valve thrombosis with international normalised ratio at or above the therapeutic range at presentation who received fibrinolysis. The fibrinolytic regimens, timing of initiation, success of fibrinolysis, risk of major and minor bleeding and ischaemic stroke were evaluated in the study.

Results: Of 30 patients included in the study 70% received immediate fibrinolysis and in 30% it was delayed. The majority of patients (90%) presented with New York Heart Association class III/IV symptoms. The mean international normalised ratio at fibrinolysis was 3.04 ± 0.70 in the immediate group and 2.42 ± 0.89 in the delayed group. Haemodynamically stable patients who had delayed initiation of fibrinolysis had a trend towards less bleeding without an increase in mortality. The rates of intracranial haemorrhage (0% vs. 7.7%), minor bleeding (12.5% vs. 25.1%) and ischaemic stroke (0% vs. 30.7%) were lower in patients who received low dose infusion compared to a conventional dose.

Conclusions: Fibrinolysis can be considered in patients with prosthetic valve thrombosis with high international normalised ratio at presentation. For haemodynamically stable patients, delayed initiation of fibrinolysis is associated with a marginally lower bleeding risk without an increase in mortality. Low dose infusion may be considered over a conventional dose as it is associated with a lower incidence of ischaemic stroke and a good rate of valve function restoration with a trend towards less bleeding.