MECHANISMS OF HEMOLYSIS AFTER MITRAL-VALVE REPAIR - ASSESSMENT BY SERIAL ECHOCARDIOGRAPHY

Objectives. We sought to determine, using serial echocardiography, the hydrodynamic mechanisms involved in the occurrence of hemolysis after mitral valve repair. Background. Recently, fluid dynamic simulation m odels have identified distinct patterns of mitral regurgitant flow dis turbances in patients with mitral prosthetic hemolysis that were assoc iated with high shear stress and may therefore produce clinical hemoly sis. Rapid acceleration, fragmentation, and collision jets were associ ated with high shear stress and hemolysis whereas slow deceleration an d free jets were not. Methods. We reviewed serial echocardiographic st udies of 13 consecutive patients with hemolytic anemia after mitral va lve repair who were referred for mitral reoperation between January 19 85 and December 1996 (group 1). Thirteen patients undergoing reoperati on for mitral regurgitation after mitral valve repair but without hemo lysis served as controls (group 2). Results. The mitral regurgitant je t was central in origin in 12 group I patients and 9 group 2 patients (Fisher exact test, p = 0.3). The other patients had para-ring regurgi tation, Group 1 patients had collision (n = 11), rapid acceleration (n = 2) or fragmentation (n = 1) jets whereas group 2 patients had slow deceleration (n = 11) or free jets (n = 2) (Fisher exact test, p < 0.0 001). One patient with hemolysis had both collision and rapid accelera tion jets. The ''culprit'' jet could be identified on the postbypass t ransesophageal echocardiography (TEE) study in only 1 patient at the t ime of initial mitral repair. Twelve group 1 patients underwent reoper ation, with subsequent resolution of hemolysis in all patients. At reo peration, the initial repair was found to be intact in 8 (67%) patient s. Conclusion. Distinct patterns of flow disturbance associated with h igh shear stress were identified by color Doppler imaging in patients dth hemolysis after mitral valve repair. The majority (92%) of these c olor flow disturbances were not present during intraoperative postbypa ss TEE study after initial mitral repair and subsequently developed in the early postoperative period. (J Am Coll Cardiol 1998;32:717-23) (C )1998 by the American College of Cardiology.