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Nisha Hosadurg, MD
Fellow Physician
University of Virginia Health System, United States
Nisha Hosadurg, MD
Fellow Physician
University of Virginia Health System, United States
Helen Sporkin
PhD Candidate
University of Virginia, United States
Gina Petroni, PhD
Professor
University of Virginia, Virginia, United States
Toral R. Patel, MD
Attending Physician
Centra Heart and Vascular Institute, United States
Yaqub Betz, MD
Fellow Physician
University of Virginia Health System, United States
Christopher Schumann, MD
Attending Physician
Cone Health Medical Group
Charlottesville, Virginia, United States
Christopher M. Kramer, MD
Chief
University of Virginia Health System
Charlottesville, Virginia, United States
Peripheral arterial disease (PAD) has a prevalence of ~ 7% in the United States, and results in a significant burden of morbidity with exercise-induced leg ischemia. Assessment of skeletal muscle perfusion and energetics by cardiovascular magnetic resonance imaging (CMR) aids in its accurate diagnosis and post-therapeutic surveillance. Arterial spin labeling (ASL)1 and chemical exchange saturation transfer (CEST)2 are reproducible non-contrast MRI methods that distinguish calf muscle perfusion and energetics in patients with and without PAD. The goal of this study is to assess the effects of catheter based or surgical revascularization on the time course of change in CEST energetics and ASL calf-muscle perfusion pre and post-intervention.
Methods:
16 subjects with known PAD [7 with chronic limb ischemia and 9 with intermittent claudication, with confirmed ankle-brachial index (ABI) of < 0.9] and planned surgical or catheter based intervention were enrolled. All subjects underwent CMR on a 3T Siemens Prisma using a knee coil wrapped around the calf of interest. ASL was performed at deflation of a thigh blood pressure cuff from 200-250 mm Hg. Following 20-30 minutes of rest, CEST was performed after plantar flexion ergometry (Ergospect) until exhaustion. Subjects also underwent ABI and 6-minute walk tests (6MWT). These were done at baseline, 6-8 weeks and 6 months after revascularization.
Results:
7 subjects (61± 3 years, 6 male) have completed the study to date, returning at 6-8 weeks and 6 months after revascularization (5 surgical and 2 percutaneous). Significant improvement in ABI [+0.34 (±0.15), P=0.001], 6 MWT [+335 (±161) feet, P=0.002] and ASL [+20.5 (±11.2) mL/min/100g, P= 0.007] were seen at 6 months post-revascularization (Table 1). There was no change in the CEST recovery time constant post-revascularization, although this was not statistically significant. There was a significant correlation between improvement in ASL and 6MWT (r=0.72, P = 0.007) at 6 months post-revascularization.
Conclusion:
Post-revascularization, calf muscle perfusion by ASL significantly improves, correlating with improvement in subjects’ 6MWT. Calf muscle energetics do not improve, suggesting a disconnect between perfusion and energetics in PAD and chronic mitochondrial dysfunction.