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Alex Sullivan @alexsullivanmd.bsky.social · 05/09/2025

Thrilled to collaborate and work alongside outstanding cardiovascular and vascular surgery colleagues at VUMC, UTSW, and Scripps!

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Alex Sullivan @alexsullivanmd.bsky.social · 05/09/2025

🤔For those wondering how can this be true, ask yourself: what is the functional limitation caused by an 80% RCA stenosis? There is no answer! Why⁉️Because function seems more driven by the microvasculature, while events are driven by the larger vessels. jamanetwork.com/journals/jam...

jamanetwork.com

Association of Physiological Stenosis Severity and Angina-Limited Exercise Time in Stable Coronary Artery Disease

This cohort study assesses the association between all commonly-used indices of physiological stenosis severity and angina-limited exercise time in patients with stable angina.

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Alex Sullivan @alexsullivanmd.bsky.social · 05/09/2025

💡Takeaways: ✅PAD walking impairment is largely driven by microvascular dysfunction. ✅Improvements in microvascular function, not conduit artery revascularization, predict walking improvement. ✅New therapies should target the microvasculature as a key mechanism of recovery.

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Alex Sullivan @alexsullivanmd.bsky.social · 05/09/2025

After exercise or revascularization: Change in ABI ❌ not associated with walking gains Change in macrovascular (popliteal artery) post-ischemic inflow ❌ not associated Change in post-ischemic MICROVASCULAR reactivity ✅ correlated with walking improvement (R=0.46; P=0.014)

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Alex Sullivan @alexsullivanmd.bsky.social · 05/09/2025

✅ ABI, macrovascular inflow, AND microvascular reactivity all correlated with walking distance (6MWT). In multivariable models, post-ischemic MICROVASCULAR reactivity was strongest (β=825.3, P=0.023).

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Alex Sullivan @alexsullivanmd.bsky.social · 05/09/2025

👩‍🔬 68 participants (50 PAD, 18 controls) 🧪 MRI measures (at rest & after ischemic stimulus): - Macrovascular (popliteal artery) inflow - Calf skeletal muscle microvascular reactivity 🚶 6-minute walk test (6MWT) Subset reassessed after exercise therapy or revascularization

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Alex Sullivan @alexsullivanmd.bsky.social · 05/09/2025

🔎 In PAD, claudication and walking limitation are not fully explained by large artery occlusive disease, as captured by reductions in ABI. We asked: Could SKELETAL MUSCLE MICROVASCULAR FUNCTION be the missing link🔗?

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Alex Sullivan @alexsullivanmd.bsky.social · 05/09/2025

Ever wonder why walking capacity varies across ABIs in those with PAD? Calf skeletal muscle microvascular dysfunction, not conduit artery occlusive disease, is the strongest driver of walking impairment in PAD. Happy to share our work in Circ CV Interventions! www.ahajournals.org/doi/10.1161/...

ahajournals.org

Microvascular Function and Ambulatory Capacity in Peripheral Artery Disease | Circulation: Cardiovascular Interventions

BACKGROUND: Patients with peripheral artery disease experience walking impairment that is incompletely explained by large-artery atherosclerotic occlusive disease and abnormal ankle-brachial index (AB...

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