Chronic intravascular hemolysis after valvular surgery.

The Phenomenon of intravascular hemolysis following cardiac valvular surgery was studied among 156 randomly selected patients. There were 76 men and 80 women, varying in ages between 15 and 71 years, with a mean age of 48.3 years. The time interval between the study and the operations ranged from 2 to 163 months with a mean of 41.1 months. The prosthetic valve was used in 129 patients; the xenograft tissue valve in 26 and the mechanical valve in 103. Subclinical hemolysis occurred in 68.9% of the 129 patients who had one or more prosthetic valve implants and in 14.8% of the 27 patients who underwent plastic repair of the mitral valve. Compared among the groups with different valve prosthesis, hemolysis could be detected in 81.6% of the patients with a mechanical prosthetic valve and in 23.1% of those with a bioprosthetic tissue valve (p less than 0.05). Twelve patients who had a valve prosthesis were documented to have symptomatic gallstones with an incidence of 9.3%. Among them, only 2 patients had biliary colic and required cholecystectomy to relieve the associated symptom. Anemia, secondary to the hemolysis, occurred in 3.8% of those with a xenograft tissue valve and 8.8% of those with a mechanical valve (p less than 0.05). None of them needed a blood transfusion. None had related renal impairment. In conclusion, the mechanical valve prosthesis has a higher incidence of hemolysis than the xenograft valve. Though the mechanical valve prosthesis has its own merits, the xenograft tissue prosthesis is superior in this respect.