Peripheral Microvascular Resistance as a Predictor for Limb Salvage

Peripheral Microvascular Resistance as a Predictor for Limb Salvage in Post-Intervention Critical Limb Ischemia Patients

Salvaging a threatened limb is the key therapeutic objective for patients with critical limb ischemia, and the achievement of limb salvage is an independent predictor of patient morbidity and mortality. Despite successful primary endovascular or surgical intervention, the corresponding symptoms of rest pain and/or non-healing ulceration in some patients may continue, and amputation in these patients is unavoidable. It is hypothesized that the functional integrity of the peripheral vascular microcirculation may be impaired in these patients. However, there are currently no techniques that allow direct quantification and visualization of the microcirculation due to the micro-vessel invisibility under angiography.

In the coronary circulation, coronary flow reserve (CFR) indicates the capacity for maximal hyperemic blood flow and reveals impaired coronary microvascular function. Studies have shown the clinical significance of measuring microvascular resistance to predict myocardial salvage after myocardial infarction. The study will explore whether this concept of coronary flow reserve can be applied peripherally to patients with critical limb ischemia in order to determine whether measuring peripheral vascular flow reserve can determine the integrity of the microcirculation to predict limb salvage after endovascular intervention.

Inclusion Criteria:

• Chronic critical limb ischemia (Rutherford 4-6).
• Age ≥18 years
• Ability and willingness to sign the IRB approved Informed Consent form

Exclusion Criteria:

• Non-reconstructable chronic total occlusive disease of the proximal inflow vessels that would make flow reserve measurements impossible.
• Non-salvageable lower extremity due to infection or overwhelming per-existing tissue loss (most critical Rutherford 6 patients).
• Inability to understand the study or a history of non-compliance with medical advice;
• History of any cognitive or mental health status that would interfere with study participation;
• Currently enrolled in any pre-approval investigational study.
• Female subjects who are pregnant or nursing or planning to become pregnant within the study period;
• Known sensitivity to contrast media, which can't be adequately pre-medicated;
• Expected life span less than 6 months.
• Unable to read/understand/sign the English Language consent form