Management of heparin-induced thrombocytopenia during thrombolytic therapy for prosthetic valve thrombosis

Heparin-induced thrombocytopenia (HIT) is a serious complication of heparin administration. As HIT may occur during the thrombolysis of prosthetic heart valve thrombosis (PVHT) due to the administration of heparin, this entity should be considered during and after sessions of this regimen. The study aim was to investigate the development, diagnosis, and management of HIT during thrombolytic therapy (TT) of PHVT.

A diagnosis of HIT was made on a clinical basis and laboratory confirmation based on a particle immunofiltration assay. Serial transthoracic echocardiography and two-dimensional transesophageal echocardiography were used to detect thrombus morphology and hemodynamic changes before and after TT sessions in 214 patients.

Four patients (1.9%) who underwent TT for PHVT were diagnosed with HIT. The mean period of onset of HIT after heparin exposure was 8.7 +/- 3.9 days, while mean platelet levels before and after heparin infusion were 308,000/mm3 and 77,250/mm3, respectively. Fondaparinux was employed as bridging therapy in three patients. TT resulted in a successful outcome in two patients, while two other patients underwent surgery for increased valve gradients (due to progression of obstructive PHVT during TT in one case, and obstructive PHVT resulting in a cerebrovascular accident in the other case).

Details are presented of the development of HIT during TT for PHVT, which resulted in an increased thrombus size immediately after successful TT. Fondaparinux may be considered as an effective bridging treatment in this regimen.