Diagnosis of Silent Coronary Ischemia with Selective Coronary Revascularization May Improve Two-year Survival of Patients with Critical Limb Threatening Ischemia.

ABSTRACT Introduction Patients with critical limb threatening ischemia (CLTI) have poor long-term survival following lower-extremity revascularization due to coexistent coronary artery disease (CAD). A new cardiac diagnostic test, coronary CT-derived fractional flow reserve (FFRCT), can identify patients with ischemia-producing coronary stenosis who may benefit from coronary revascularization. We sought to determine whether diagnosis of silent coronary ischemia prior to limb salvage surgery with selective post-operative coronary revascularization can reduce adverse cardiac events and improve survival of CLTI patients compared to standard care. Methods CLTI patients with no cardiac history or symptoms who had pre-operative testing to detect silent coronary ischemia with selective post-op coronary revascularization (Group I) were compared to patients with standard pre-op cardiac clearance and no elective post-op coronary revascularization (Group II). Both groups received guideline-directed medical care. Lesion-specific coronary ischemia in Group I was defined as FFRCT ≤0.80 distal to a stenosis with severe ischemia defined as FFRCT≤0.75. Endpoints included all-cause death, cardiovascular (CV) death, myocardial infarction (MI), MACE (CV death, MI, unplanned coronary revascularization or stroke) through 2 year follow up. Results Groups I (n=111) and II (n=120) were similar regarding age (66±9 vs 66±7 years), gender (78 vs 83% male), co-morbidities and surgery performed. In Group I unsuspected, silent coronary ischemia was found in 71 of 103 patients (69%) with severe ischemia in 58% and left main coronary ischemia in 8%. Elective post-operative coronary revascularization was performed in 47 of 71 patients with silent ischemia (66%). In Group II the status of silent coronary ischemia was unknown. Median follow up was >2 years in both groups. Two-year outcomes of Group I compared to Group II, were as follows: all-cause death 8.1% vs 20.0%, HR=0.38 (95% CI 0.18-0.84), P=.016; CV death 4.5% vs 13.3%, HR=0.32 (95% CI 0.11-0.88), P=0.028; MI 6.3% vs 17.5%, HR=0.33 (95% CI 0.14-0.79), P=0.012; and MACE 10.8% vs 23.3%, HR=0.44 (95% CI 0.22-0.88), P=0.021. Conclusions Pre-operative evaluation of CLTI patients with no known CAD using coronary CT-derived FFR revealed silent coronary ischemia in 2 of 3 patients. Selective coronary revascularization of patients with silent coronary ischemia after recovery from limb salvage surgery resulted in fewer CV deaths and MIs and improved two-year survival compared to CLTI patients receiving standard cardiac evaluation and care. Prospective controlled studies are needed to further define the role of FFRCT in the evaluation and treatment of patients with CLTI.