There are two treatment options for revascularizing patients with critical limb ischemia: bypass surgery and percutaneous vascular intervention (PVI). PVI is less invasive but has high immediate technical failure rates (20%) and high re-intervention rates (20%). The most common mode of immediate failure is the inability to enter/cross the lesion. With current imaging (X-ray angiography, CTA, Duplex ultrasound) it is difficult to predict which lesions will be soft enough to cross with a wire to make PVI possible. Physicians have responded with a “percutaneous-first” strategy where they attempt PVI in all patients and perform surgery if PVI fails. This requires more procedures per index limb at significant cost to healthcare systems and delays definitive revascularization. Additionally, there is evidence that surgical bypass after failed PVI results in worse outcomes, including higher amputation rates within 1 year.
These issues highlight the critical need for improved diagnostic accuracy to inform patient selection. We have developed and validated MR methods to distinguish hard PAD lesions (densely calcified or collagenous) that would be at high risk of PVI failure from soft lesions that would be amenable to PVI. The impact of this work will help to reduce PVI failure rates, reduce time to definitive revascularization and reduce costs for additional procedures and investigations.