Change of c-Myc expression and cardiac hypertrophy in patients with aortic valve replacement.
BACKGROUND
Long-term volume overload to the left ventricle (LV) due to aortic regurgitation (AR) tends to cause severe impairment in LV function that cannot be reversed even with aortic valve replacement (AVR). Recently, we reported that the protooncogene c-myc is related to the onset of the cardiac hypertrophy and LV dysfunction in patients with chronic AR. However, it is still unclear whether c-myc is related to reversibility of the cardiac hypertrophy or LV dysfunction after AVR.


RESULTS
Twenty patients with isolated chronic AR who underwent AVR were included in this study. LV function was calculated before and after AVR. After AVR, end-systolic volume index (ESVI) and enddiastolic volume index (EDVI) were improved, but not mass index (LVMI). However, normalization of ESVI and EDVI was observed only in 12 and 9 patients, respectively. Preoperatively, c-Myc protein was expressed in the myocardium of 16 out of 20 patients with an average point count of 35+/-30%. After AVR, c-Myc protein was observed only in 2 patients. Preoperative ejection fraction (EF), ESVI, and postoperative end-systolic stress (ESS)/ESVI had significant correlation to postoperative cell diameter (CD). Percent c-Myc protein expression before the operation was significantly correlated to postoperative CD, ESVI, and ESS/ESVI. Average c-Myc expression was higher in patients who showed normalization of CD and ESS/ESVI after AVR than the patients who did not.


CONCLUSIONS
These data suggest that preoperative expression of c-Myc can be indicative of the reversibility of myocardial cellular hypertrophy and LV dysfunction.
Taketani
S
S
Department of Surgery Course of Interventional Medicine E1, and Allied Health Sciences, Osaka University Graduate School of Medicine, Japan.
Sawa
Y
Y
Ichikawa
H
H
Ohtake
S
S
Nishimura
M
M
Kawaguchi
N
N
Matsuda
H
H
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001022:Aortic Valve Insufficiency / Q000150:complications* / Q000601:surgery*; D001707:Biopsy, Needle; D004259:DNA-Directed DNA Polymerase; D005260:Female; D005500:Follow-Up Studies; D006334:Heart Function Tests; D019918:Heart Valve Prosthesis Implantation / Q000379:methods*; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000209:etiology* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology*; D011184:Postoperative Period; D011300:Preoperative Care; D016271:Proto-Oncogene Proteins c-myc / Q000032:analysis*; D012016:Reference Values; D012680:Sensitivity and Specificity
D016271:Proto-Oncogene Proteins c-myc; C070331:Tli polymerase; D004259:DNA-Directed DNA Polymerase