Evaluation of intravascular hemolysis with erythrocyte creatine in patients with cardiac valve prostheses.
OBJECTIVE
To detect intravascular hemolysis in patients with cardiac valve prostheses. Erythrocyte creatine, a marker of erythrocyte age that increases with shortening erythrocyte survival, was evaluated with other hemolytic markers and hemodynamic parameters.


METHODS
Prospective study.


METHODS
Erythrocyte creatine was enzymatically assayed in 33 patients with prosthetic valves, including 15 patients with aortic valve replacement, 13 patients with mitral valve replacement, and 5 patients with double-valve (aortic and mitral) replacement, and 33 control subjects. Blood flow velocity and valvular regurgitation were determined by Doppler echocardiography. Other hemolytic markers (lactate dehydrogenase [LDH], reticulocyte count, and haptoglobin) and cardiac muscle markers (myoglobin and myosin light chain 1) were also measured.


RESULTS
Erythrocyte creatine and LDH levels were significantly higher (p < 0.0001) and the haptoglobin level was lower (p < 0.0001) in patients with a prosthetic valve as compared with control subjects. However, there were no significant differences in these markers between those with (n = 17) and without (n = 16) regurgitation. Patients with high erythrocyte creatine levels (> 1.8 micro mol/g hemoglobin) exhibited significantly higher total peak flow velocity (sum of peak flow velocities at mitral and aortic valves) than those with normal erythrocyte creatine levels (p = 0.006). Erythrocyte creatine had a significant correlation with total peak flow velocity (r = 0.64, p < 0.0001), but LDH and haptoglobin had no significant correlation with total peak flow velocity. Patients with high LDH levels (> 460 IU/L) showed significantly higher myoglobin (p = 0.008) and myosin light chain 1 (p = 0.02) than those with normal LDH levels, whereas erythrocyte creatine was not related to cardiac muscle markers.


CONCLUSIONS
Erythrocyte creatine is a quantitative and reliable marker for intravascular hemolysis in patients with prosthetic valves. Mild hemolysis is ascribable to valvular flow velocity rather than regurgitation.
Okumiya
Toshika
T
Department of Laboratory Medicine, Faculty of Medicine, Kochi Medical School, Nankoku, Japan. okumiyat@med.kochi-u.ac.jp
Ishikawa-Nishi
Mitsuko
M
Doi
Tadafumi
T
Kamioka
Mikio
M
Takeuchi
Hiroaki
H
Doi
Yoshinori
Y
Sugiura
Tetsuro
T
D000368:Aged; D001021:Aortic Valve / Q000601:surgery; D015415:Biomarkers / Q000032:analysis; D016022:Case-Control Studies; D002470:Cell Survival; D003401:Creatine / Q000032:analysis / Q000378:metabolism*; D015150:Echocardiography, Doppler; D004906:Erythrocyte Count; D005260:Female; D006349:Heart Valve Diseases / Q000175:diagnosis / Q000601:surgery*; D006350:Heart Valve Prosthesis / Q000009:adverse effects*; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects / Q000379:methods; D006461:Hemolysis; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000601:surgery; D011336:Probability; D011379:Prognosis; D011446:Prospective Studies; D012016:Reference Values; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index
D015415:Biomarkers; D003401:Creatine