Anticoagulation with unfractionated heparin in patients with prosthetic valve thrombosis- a single center study
Authors: Kalkan S , Kalcik MACIT , Ozan GURSOY , Ahmet GUNER , Sabahattin GUNDUZ , Bayam EMRAH , Yesin MAHMUT , Ozkan MEHMET 
Published: February 2022

Abstract

Funding Acknowledgements
Type of funding sources: None.

BACKGROUND
Surgical and thrombolytic therapy (TT) are used as effective treatment methods to treat obstructive Prosthetic valve thrombosis (PVT). However, TT is usually contraindicated in patients who suffer PVT in the early postoperative period (first three weeks) or those who present with an acute cerebral thromboembolism. Unfractionated heparin (UFH) infusion seems to be one of the appropriate treatment options in such patients.

PURPOSE
In this single-center study, we aimed to investigate the efficacy of UFH therapy in patients with PVT.

METHODS
This retrospective, observational, single center study included 136 PVT patients (mean age: 50.3 ± 14.6 years; female: 81, male: 55) who did meet the following criteria: (i) PVT with &gt;10 mm thrombus lenght; (ii) a thrombus with embolic risk despite no thrombolytic indication, accompanied with clinical entities such as gradient increase on the valve, acute coronary syndrome, infective endocarditis, and TIA.The success criteria of the treatment was defined as a 75% reduction in the thrombus burden in the absence of major non-fatal complications. Patients with a 50 75% reduction in the thrombus burden were considered as partially successful. The development of major complications indicated treatment failure.

RESULTS
The study included 16 (11.8%) aortic, 97 (71.3%) mitral, 19 (14%) aortic and mitral, 4 (2.9%) tricuspid prosthesis, with 27 (19.9%) obstructive and 109 (80.1%) non-obstructive thrombosis. During the follow-up, 66 (48,5%) patients showed a regression &gt; 50% in the thrombus burden without facing death or major non-fatal complications; therefore the UFH therapy was considered successful in these patients. Fifty-six patients had a &lt; 50% reduction in thrombus load despite the UFH treatment. Furthermore, 14 (10.3 %) patients suffered major complications. UFH treatment was assumed unsuccessful in these 70 patients (51.5%). Nature of the thrombus (27.1% vs. 12.1%; p = 0.028), thrombus area (1.1 (in a range of 0.7-1.6) cm2 vs. 0.8 (in a range of 0.6-1.2) cm2; p = 0.005] and the duration of UFH treatment (15.1 ± 6.7 days vs. 11.8 ± 7.2 days; p = 0.005) were significantly higher in the unsuccessful UFH group. The parameters that were found to be significantly different in the univariate analyses between patients with successful and unsuccessful UFH treatment were further evaluated in multivariate regression analysis. As a result, the obstructive nature of the thrombus (RR: 3.088, 95% CI: 1.191-8.006; p = 0.020), increased thrombus area (RR: 2.400, 95% CI: 1.184-4.864; p = 0.015), and increased duration of UFH therapy (RR: 1.073 95% CI: 1.016-1.133; p = 0.012) were identified as independent predictive parameters for a failed UFH therapy.

CONCLUSIONS
In this study, we have demonstrated that UFH treatment may be beneficial in patients with PVT that are unsuitable for surgical and TT. Our findings have revealed that the most significant factor affecting the success of UFH treatment is the thrombus burden. Abstract table 1 Abstract table 2