Clinical Value of Serial Transesophageal Echocardiography in Thrombolytic Treatment of Mechanical Prosthetic Valve Thrombosis

Thrombolytic therapy (TT) for thrombosed prosthetic heart valves have been used as an altemative to surgical thrombectomy and valve replacement. However, diagnostic criteria, indications and delivery methods for TT have not been standardized. There do not exist definitive established guidelines for TT of obstructive type (O) prosthetic valve thrombosis (PVT), and may more debatable is whether TT is a reasonable therapy for nonobstructive type (NO) PVT. The aim of this study was to investigate the potential value of_serial transesophageal echocardiography (TEE) guidance for more effective and safer administration of TT in prosthetic valve thrombosis (PVT), and to investigate elinical importance of the morphological characteristics of PVT (obstruction, mobility) determined by TEE and fibrinolytic infusion protocol (fast vs slow) for TT success and complications. The study group consisted of 28 pts (F 18, M 10, mean age 36±12) who underwent 50 TT sessions for the treatment of 32 PVT (mitral 24, aortic 6, mitral and aortic 1, tricuspid ı ) episodes. Patients with obstructive (O) thrombus, and those with nonobstructive (NO) thrombus who either had a history of embolization or had a large thrombus mass (~10 mm base diameter and/or~5 mm mobile segment length) were accepted as candidates for TT. Streptokinase (SK) was the initial agent in all primary PVT episodes. In early experience (n=13) a total of 1.5 million units of SK was adınİnistered in 3 hours. In subsequent patients (n=14) a slow infusion of60.000-ıOO,OOO U/hr for a total of 15-24 hours was given. Urokinase (n=2) or rt-PA (n=7) was chosen for recurrent thrombus or in the case of failure of two subsequent SK sessions. The overall TT success rate was 88% (29/33) in all episodes, and were 88% (22/25) and 85.7 % (6!7) in mitral and aortic PVT episodes, respective1y (p>O.l). Complete TT success was achieved in pts with tricuspid PVT. The overall success rate was found to be unassociated with the valve types, thrombus morphology (obstruction, mobility), NYHA classes, and infusion protocol of SK. Complications of thrombolytic treatment w as see n in 6 ( 18.7%) 326 thrombotic episodes. Major complications included death in ı (3. ı % ), coronary embolization in ı (3. 1%) and cerebral embolization in ı (3. ı %) episode. Minor bleeding was noted in 3 (9.3%) of the episodes. Of interest all major complications occurred in the group that received the rapid infusion of SK as initial treatment.
CONCLUSIONS
(ı) TEE has greatly improved the recognition of detailed morphologic characteristics of PVT, (2) TT success seems to be not different for the mitral and aortic valve trombosis, (3) prolonged fibrinolytic infusion protocol may decrease the ineidence of embolic ev en ts, ( 4) functional status (NYHA Class III and IV) of pts during TT does not tirnit successful outcome, and (5) not only fixed obstructive PVT, but also NO PVT still constitute an indication for TT because of tendeney for embolic events.