Management and Outcomes of Prosthetic Valve Thrombosis. An Australian Case Series From the Northern Territory.

Background: Prosthetic valve thrombosis (PVT) is an uncommon but serious cause of morbidity and mortality after cardiac valve implantation. The most common cause leading to PVT is inadequate anticoagulation. Royal Darwin Hospital is a major referral centre for the Top End of Australia and is unique in having a high burden of rheumatic heart disease (RHD) requiring valve surgery, issues with adherence with oral anticoagulants, and the absence of onsite cardiothoracic facility.

Methods: We report clinical characteristics and outcomes of consecutive patients presenting with PVT to a single centre without on-site cardiothoracic surgery.

Results: Thirty-two (32) episodes involving 21 patients were retrospectively identified between 2000 and 2017. Our cohort had an average age of 37 years. Nineteen (19) patients were of Aboriginal or Torres Strait Islander descent. All valves were mechanical, except for one bioprosthetic mitral valve, with average time from implantation to initial PVT 5.1 years. The majority of patients were in New York Heart Association (NYHA) class III and IV (6%, and 66%, respectively). Anti-coagulation was sub-therapeutic in 88% of presentations. Eleven (11) (34%) presentations were recurrent PVT involving eight patients. Twenty-six (26) (82%) episodes were treated with thrombolytic therapy which achieved complete success in 65% and partial success in 19%. Five (5) patients received a second dose of the lytic agent. Of the four patients not responding to thrombolytic therapy, two died and two were urgently transferred to a facility with on-site cardiothoracic surgery. Five (5) out of 32 episodes resulted in death (16%) with overall mortality 24% for the cohort over the entire time period. Thrombolytic therapy was associated with five major bleeding episodes (16%) including two fatal bleeds.

Conclusions: Prosthetic valve thrombosis is a rare but life-threatening complication of prosthetic valves, with the vast majority of patients found to be inadequately anticoagulated. Despite differences in thrombolytic agents these were successful in the majority of patients.