CARDIOVASCULAR ENGINEERING Journal for Extracorporeal Circulation, Assist Devices,Transplantation and Artificial Organs
	Volume 8, 2003, No 1-2

Myocardial Fatty Acid Uptake in Patients with Severe Aortic Stenosis and Left Ventricular Dysfunction: Effects of Corrective Surgery and Long-term Follow-up Study
G. Notohamiprodjo, H. Meyer, R. Körfer

Background: Identification of patients with aortic stenosis and left ventricular dysfunction who may benefit from valve replacement is challenging. The clinical outcome after surgery was debated controversially. It was to elucidate, whether the indices of myocardial fatty acid metabolism may be helpful in identifying such patients and may predict prognosis.
Methods and Results: Twenty-one patients with severe aortic stenosis and left ventricular dysfunction underwent myocardial dual isotope (²⁰¹Tl and ¹²³IPPA) scintigraphy prior to, 2 weeks and 1-2 years after valvular replacement. Patients were followed for 10 years. Prior to operation, the rate constant for IPPA influx (k₁*), the maximal velocity (V_max) and the washout rate (WO) was reduced significantly compared to normals (0.373±0.11 min^-1, 0.276±0.019 µmol/(g·min) and 37.1±8% vs. 0.542±0.134 min^-1, 0.37±0.013 µmol/(g·min) and 53.5±7.4%, p<0.001). The Michaelis-Menten constant K_M was almost unchanged (0.288±0.036 vs. 0.24±0.024 µmol/g). Two weeks after surgery, the recovery of the myocardial fatty acid transport and metabolism was not observed. At 1-2 years follow-up, k₁*, V_max and WO improved significantly (0.458±0.14 min^-1, 0.368±0.03 µmol/(g·min) and 45.9±9.6%, p<0.001). Regression of hypertrophy and further improvement of left ventricular performance were noted. The indices of metabolism correlate well with the indices of hypertrophy. k₁*, WO, mass index and wall thickness were identified significant predictors of outcome. On survival analysis for subgroups, k₁*<0.3 min^-1, WO <40% and LV-mass >300g indicated poor prognosis. The strongest predictor was k₁*.
Conclusions: Myocardial fatty acid transport and metabolism in severe aortic stenosis and ventricular dysfunction are impaired. The metabolic indices distinct patients in whom metabolic deterioration prior to valvular replacement is reversible and predict good prognosis from those in whom myocardial damage is irreversible and indicate poor prognosis.

Key words: aorta, stenosis, hypertrophy, fatty acids, surgery, follow-up studies

Gunawan Notohamiprodjo, M.D., Ph.D.
Department of Diagnostic Radiology and Nuclear Medicine
Marienstr. 28-28a
D-32427 Minden
Germany
E-mail: lim.noto@t-online.de

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