Purpose: We used P-31 magnetic resonance spectroscopy (MRS) and near-infrared spectroscopy (NIRS) as a means of quantifying abnormalities in calf muscle oxygenation and adenosine triphosphate (ATP) turnover in peripheral vascular disease (PVD).
Methods. Eleven male patients with PVD (mean age, 65 years; range, 55-76 years) and nine male control subjects of similar age were observed in a case-control study in vascular outpatients. Inclusion criteria were more than 6 months' calf claudication (median, 1.5 years; range, 0.6-18 years); proven femoropopliteal or iliofemoral occlusive or stenotic disease; maximum treadmill walking distance (2 km/h, 10 degrees gradient) of 50 to 230 m (mean, 112 m); ankle-brachial pressure index of 0.8 or less during exercise (mean, 0.47; range, 0.29-0.60). Exclusion criteria included diabetes mellitus, anemia, and magnet contraindications. Simultaneous P-31 MRS and NIRS of lateral gastrocnemius was conducted during 2 to 4 minutes of voluntary 0.5 Hz isometric plantarflexion at 50% and 75% maximum voluntary contraction force (MVC), followed by 5 minutes recovery. Each subject was studied three times, and the results were combined.
Results: Compared with control subjects, patients with PVD showed (1) normal muscle cross-sectional area, MVC, ATP turnover, and contractile efficiency (ATP turnover per force/area); (2) larger phosphocreatine (PCr) changes during exercise (ie, increased shortfall of oxidative ATP synthesis) and slower PCr recover), (47% +/- 7% [mean +/- SEM] decrease in functional capacity for oxidative ATP synthesis, P =.001); (3) faster deoxygenation during exercise and slower postexercise reoxygenation (59% +/- 7% decrease in rate constant, P =.0009), despite reduced oxidative ATP synthesis; (4) correlation between PCr and NIRS recovery rate constants (P
Conclusion: The primary lesion in oxygen supply dominates muscle metabolism. Reduced force-generation in patients who are affected more may protect muscle from metabolic stress.
|Number of pages||8|
|Journal||Journal of Vascular Surgery|
|Publication status||Published - Dec 2001|
|Event||2nd Colloquium on Mitochondria and Myopathics - HALLE SAALE, Germany|
Duration: 31 Mar 2000 → 2 Apr 2000
- PERIPHERAL VASCULAR-DISEASE
- HUMAN SKELETAL-MUSCLE
- ARTERIAL OCCLUSIVE DISEASE
- INTERMITTENT CLAUDICATION
- CALF MUSCLES
- ELDERLY SUBJECTS
- ATP SYNTHESIS
- FIBER TYPES