Predictive Value of Combining the Ankle-Brachial Index and SYNTAX Score for the Outcome in STEMI Patients Undergoing Primary Percutaneous Coronary Intervention

Abstract
Background: The Synergy between PCI with TAXUS and Cardiac Surgery (SYNTAX) score is effective for prediction of clinical outcome after Percutaneous Coronary Intervention (PCI). However, its predictive ability is low because it reflects only the coronary characterization.
Objective: Evaluation of predictive value of combining the Ankle-Brachial Index (ABI) and SYNTAX score for the outcome in STEMI patients undergoing primary percutaneous coronary intervention.
Methods: A prospective observational cohort study con-ducted from June 2016 to May 2017 at Cardiovascular Med-icine Department, Tanta University Hospitals in Gharbia Governorate, Egypt. The study enrolled 90 consecutive adult patients of both genders who were diagnosed with definite ST-segment elevation myocardial infarction within 12 hours from the time of symptoms onset, and were treated by primary percutaneous coronary intervention. SYNTAX score was calculated based on its results. ABI-SYNTAX score was calculated by first reclassifying the ABI and SYNTAX scores and then adding them. ABI <0.4 was classified as 2, 0.4 to 0.9 as 1, >0.9 to 1.3 as 0 points; and SYNTAX score <22 was classified as 0, 23 to 32 as 1, and >33 as 2 points. The resulting scores were added. Patients were classified into 3 groups: ABI-SYNTAX score low (0), ABI-SYNTAX score moderate (1 or 2), and ABI-SYNTAX score high (3 or 4).
Results: Incidence of MACEs was higher among patients with high ABI-SYNTAX score. From the total incidence of MACEs in the study population (n=17), 12 were present in group III (70.6%), 4 in group II (23.5%) and 1 in group I (5.9%). ABI-SYNATX score was more sensitive than SYNTAX score alone for detection of occurrence of MACEs in patients with high score (group III). Incidence of secondary endpoints, defined as stent thrombosis, in stent restenosis, re-hospitalization with acute coronary syndrome and target lesion revascularization, was higher in group III.
Conclusion: ABI- SYNTAX score is an independent prognostic factor for both in-hospital adverse outcomes, as well as, short-term adverse outcomes among STEMI patients who underwent primary PCI. It improved the ability of the SYNTAX score which assesses the angiographic characteristics and complexity of coronary artery lesions by combining the SYNTAX score with ABI. The predictive value of ABI-Syntax score with respect to MACEs was superior to Syntax score alone.