Clinical significance of early thrombosis after prosthetic mitral valve replacement: a postoperative monocentric study of 680 patients.

OBJECTIVES

The aim of this study was to evaluate the incidence of early thrombosis, its prognostic significance, and the therapeutic implications.

BACKGROUND

Transesophageal echocardiography (TEE) is the method of choice for detecting symptomless early postoperative thrombosis of prosthetic valves. However, the clinical significance is not yet known.

METHODS

Between June 1994 and December 2000, 680 consecutive patients underwent TEE on day 9 after mechanical mitral valve replacement, to search for early thrombosis. Initially, end points were the in-hospital outcome and treatment. Patients were also evaluated 34 +/- 22 months after surgery.

RESULTS

Sixty-four early thrombi were detected (9.4%). Two early obstructive were treated by redo-surgery. Sixty-two nonobstructive benefited from medical treatment. The patients were allocated into two groups as a function of the maximum size of thrombus: <5 mm in 29 patients (group A) and > or =5 mm in 35 (group B). During early follow-up, we observed one complicated course in group A and eight in group B. In the long-term survey, three complications were noted in group A and 11 in group B. Incidence of early (p = 0.027) and long-term (p = 0.04) complications were significantly different in the two subsets.

CONCLUSIONS

This study confirms the incidence of early thrombi after mechanical mitral valve replacement detected by TEE. A small (<5 mm) nonobstructive thrombus seems benign, and our experience argues in favor of medical treatment. Prognosis appears more serious for large thrombi. Medically aggressive therapy and further surgery should be considered in cases of obstructive thrombosis or large and mobile nonobstructive thrombosis.