EARLY TRANSESOPHAGEAL ECHOCARDIOGRAPHY AF TER MITRAL-VALVE REPLACEMENT - SIGNIFICANCE OF SMALL ABNORMAL PROSTHETIC ECHOES

The aim of this study was to determine the frequency, significance and prognosis of small, abnormal, strand-like echos observed by early tra nsoesophageal echocardiography after mitral mechanical valve replaceme nt with hemi-disc prostheses. One hundred and twenty nine consecutive patients operated between October 1988 and June 1992 underwent transoe sophageal echocardiography on average 15 +/- 7 days after surgery. A s econd transoesophageal echocardiography was performed in 52 patients o n average 8 months after the first postoperative examination. The freq uency of small strand-like echos and of non-obstructive thromboses of the valve at the initial transoesophageal examination was 43 % and 8.5 % respectively. A multivariate analysis showed that the only independ ant predictive factor for prosthetic valve strands was spontaneous int ra-atrial contrast (p < 0.01). The presence of strands was significant ly related to the prevalence of early thrombo-embolic events (confirme d non-obstructive valve thrombosis and systemic embolism). Strands wer e observed in 80 % of cases with early thromboembolic complications co mpared with only 38 % of cases with no early thromboembolic events (p < 0.04). Univariate analysis showed that the protamine/heparin ratio a t the end of cardiopulmonary bypass and the percentage of ineffective postoperative heparinisation were higher in patients with these small, abnormal echos (p < 0.05 and p < 0.001, respectively). These appearan ces disappear at long-term transoesophageal echocardiographic control examinations in about half the cases. The authors conclude that the ma jority of these small, abnormal echos are thrombotic in nature and are associated with a higher thromboembolic risk, justifying effective an ticoagulation in the first postoperative hours whenever possible, cons idering the risk of bleeding. The indications of early postoperative t ransoesophageal echocardiography should be studied after mitral valve replacement.