Myocardial tumor necrosis factor–α expression does not correlate with clinical indices of heart failure in patients on left ventricular assist device support

Background. Mechanical unloading with a left ventricular assist device (LVAD) can improve clinical indices of heart failure and alter myocardial tumor necrosis factor–α (TNFα) expression, but a correlation between clinical and molecular indices has not been established. Methods. We enrolled 14 patients with end-stage heart failure treated with drugs and mechanical unloading in a protocol including the collection of myocardial tissue samples at LVAD implantation and explantation. Ten nonfailing donor hearts served as controls. TNFα expression was measured by quantitative reverse transcription polymerase chain reaction. Clinical indices of heart failure were retrospectively analyzed and correlated with myocardial TNFα expression. Results. Left ventricular end-diastolic dimension decreased (p < 0.01) and cardiac index (p < 0.001) increased with unloading. Abnormal values of serum sodium, creatinine, blood urea nitrogen, glutamic-oxaloacetic transaminase, glutamic-pyruvic transaminase, and albumin showed a trend toward normalization with mechanical unloading. TNFα expression was increased in 5 of 14 patients and decreased with mechanical unloading in 4 of them. Surprisingly, there was no correlation between mRNA levels of TNFα and any of the clinical indices studied. Conclusions. Although clinical indices of heart failure improve and elevated levels of myocardial TNFα expression decrease with mechanical unloading, there is no correlation between the two. Thus, clinical and molecular indices of heart failure in LVAD-supported patients do not always correlate.