title: High-energy phosphate metabolism during calf ergometry in patients with isolated aorto-iliac artery stenoses.
abstract: OBJECTIVE
  Patients with peripheral arterial disease (PAD) and aorto-iliac atherosclerotic lesions suffer from a broad range of complaints, such as pain at the hip, the thigh, and calf claudication. The purpose of this study was to investigate the high-energy metabolism in the calf muscle of patients with PAD with isolated aorto-iliac stenoses during incremental plantar flexion exercise.
  
  
  METHODS
  Using a 1.5 T whole-body magnetic resonance (MR) scanner, 12 patients with PAD with uni- or bilateral aorto-iliac atherosclerotic lesions and 10 healthy male controls underwent serial phosphor-31 MR spectroscopy during incremental exercise at 2, 3, 4, and 5 W. The phosphocreatine (PCr) time constants were calculated for each increment and recovery using a monoexponential model. In the patient group, the run-off resistance was determined on MR angiograms. In both the patients and the controls, the ankle brachial pressure index was measured.
  
  
  RESULTS
  The diseased legs exhibited significantly increased PCr time constants during the second and the third workload increment at 3 and 4 W, but not during the first increment at 2 W and recovery compared with normal controls. Only 3 diseased legs succeeded the last increment at 5 W. We detected significant correlations between the ankle brachial pressure index scores and the PCr time constants when including both the diseased and the control legs. The diseased legs showed a significant correlation with the run-off resistance only during the first increment.
  
  
  CONCLUSIONS
  Our study shows that the impairment of muscle metabolism, expressed by prolonged PCr time constants, occurs with greater work intensities in patients with aorto-iliac disease compared with patients with multisegmental PAD, as recently published, whereas our patients collective exhibited normal PCr recovery time constants. Our findings may help to understand variability of clinical symptoms in aorto-iliac PAD.
authors.affiliation: Department of Radiology, Division of Vascular Surgery, Innsbruck Medical University, Innsbruck, Austria. michael.schocke@i-med.ac.at
authors.forename: Michael F H
authors.initials: MF
authors.lastname: Schocke
authors.forename: Regina
authors.initials: R
authors.lastname: Esterhammer
authors.forename: Stephanie
authors.initials: S
authors.lastname: Ostermann
authors.forename: Wolfram
authors.initials: W
authors.lastname: Santner
authors.forename: Olaf
authors.initials: O
authors.lastname: Gorny
authors.forename: Gustav
authors.initials: G
authors.lastname: Fraedrich
authors.forename: Werner R
authors.initials: WR
authors.lastname: Jaschke
authors.forename: Andreas
authors.initials: A
authors.lastname: Greiner
mesh_terms: D000368:Aged; D001011:Aorta / Q000473:pathology; D001795:Blood Pressure Determination / Q000379:methods; D003251:Constriction, Pathologic / Q000175:diagnosis*; D005080:Exercise Test; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007083:Iliac Artery / Q000000981:diagnostic imaging* / Q000473:pathology; D007866:Leg; D018810:Magnetic Resonance Angiography; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000098:blood supply / Q000503:physiopathology*; D016491:Peripheral Vascular Diseases / Q000175:diagnosis / Q000503:physiopathology*; D010725:Phosphocreatine / Q000378:metabolism*; D011859:Radiography
chemical_list: D010725:Phosphocreatine