Local relation between oxidative metabolism and perfusion in leg muscles of patients with heart failure studied by magnetic resonance imaging and spectroscopy

BACKGROUND: We studied the local relation of muscle perfusion and metabolism in patients with severe chronic heart failure. Alterations of skeletal muscle blood flow and oxidative capacity contribute to exercise intolerance in these patients. The interdependence of both parameters has often been questioned.
METHODS AND RESULTS: With the use of nuclear magnetic resonance, we quantified leg and muscle perfusion during reactive hyperemia in 7 patients with heart failure (New York Heart Association class III and IV) and 7 age-matched control subjects from the difference in longitudinal relaxation rate (1/T1). By using 31P nuclear magnetic resonance spectroscopy, we assessed oxidative metabolism from the creatine rephosphorylation time constant after a short ischemic exercise. Phosphocreatine recovery is slowed (74.6 +/- 11.3 vs 49.9 +/- 13.9 seconds, p = .002) and reactive hyperemic flow is reduced (48.5 +/- 24.9 vs 113 +/- 30.4 mL/100 mL per minute, p = .0005).
CONCLUSIONS: By using a totally noninvasive protocol, we demonstrated that reactive hyperemic flow correlates with oxidative capacity in calf muscles from patients with heart failure, showing that exercise performance and local circulatory dysfunction are decreased in parallel in severe heart failure.