Reoperation for hemolytic, anaemia complicating mitral valve repair

To identify the possible cause(s) of hemolysis after mitral valve repair for mitral regurgitation (MR) and to evaluate the late outcome of surgical treatment.

We reviewed all patients who had reoperation after valve repair for mitral regurgitation. Ten patients had reoperation because of hemolytic anaemia. The diagnosis of hemolysis was made by decreased serum haptoglobin, elevation of serum lactate dehydrogenase (LDH), and schistocytosis. No other causes of anaemia or hemolysis were identified in these six men and four women (ages 35-84 years; median 59 years). Interval between initial mitral valve repair and reoperation ranged from 40 to 165 days (median 87 days), and prior to reoperation, red cell transfusions (range 2-12 units; median 5 units) were required in all patients. Seven patients were symptomatic: two complained of easy fatigability and five were severely limited. Transesophageal echocardiogram during hemolytic evaluation showed only mild MR in two patients, moderate in five, moderately severe in two and severe in one.

Etiology of hemolysis was suggested from echocardiography and confirmed at reoperation. In one patient, an eccentric MR jet struck a pledget of a commissural annuloplasty. In the remaining nine patients, the regurgitant jet struck a non-endothelialized portion of the annuloplasty ring (Carpentier-Edwards n = 5; Duran n = 2; Cosgrove-Edwards n = 2). Seven patients had prosthetic replacement and three patients had re-repair. There were no operative deaths and all patients had resolution of hemolytic anaemia.

Relatively minor degrees of regurgitation after mitral valve repair can produce hemolytic anaemia which is manifested within the first few postoperative months. Most patients are highly symptomatic because of anaemia. The mechanism of red cell destruction is a high velocity eccentric stream of blood impacting on a small area of a prosthetic ring or pledget. This process retards endothelialization of the ring. Reoperation with re-repair or mitral valve replacement is safe and effectively relieves the hemolysis.