Clinical and biochemical markers of coronary artery calcification progression after elective coronary artery bypass grafting

Abstract

Aim. To assess the relationship of various clinical and biological markers of bone metabolism with the progression of coronary artery calcification (CAC) in patients with stable coronary artery disease (CAD) within 5 years after coronary artery bypass grafting (CABG).Material and methods. This single-center prospective observational study included 111 men with CAD who were hospitalized for elective CABG. In the preoperative period, all patients underwent duplex ultrasound of extracranial arteries (ECA) and multislice computed tomography (MSCT) to assess CAC severity using the Agatston score, as well as densitometry with determination of bone mineral density in the femoral neck, lumbar spine and T-score for them, In all participants, the following bone metabolism biomarkers were studied: calcium, phosphorus, calcitonin, osteopontin, osteocalcin, osteoprotegerin (OPG), alkaline phosphatase, parathyroid hormone. Five years after CABG, ECA duplex ultrasound, MSCT coronary angiography and bone metabolism tests were repeated. Depending on CAC progression (>100 Agatston units (AU)), patients were divided into two groups to identify significant biomarkers and clinical risk factors associated with CAC progression.Results. For 5 years after CABG, contact with 16 (14,4%) patients was not possible; however, their vital status was assessed (they were alive). Death was recorded in 4 (3,6%) cases (3 — due to myocardial infarction, 1 — due to stroke). In 18 (19,7%) cases, non-fatal endpoints were revealed: angina recurrence after CABG — 16 patients, myocardial infarction — 1 patient, emergency stenting for unstable angina — 1 patient. There were no differences in the incidence of events between the groups with and without CAC progression. According to MSCT 5 years after CABG (n=91 (81,9%)), CAC progression was detected in 60 (65,9%) patients. Multivariate analysis allowed to create a model for predicting the risk of CAC progression, which included following parameters: cathepsin K <16,75 pmol/L (p=0,003) and bone mineral density <0,95 g/cm3 according to femoral neck densitometry before CABG (p=0,016); OPG <3,58 pg/ml (p=0,016) in the postoperative period 5 years after CABG.Conclusion. Within 5 years after CABG, 65,9% of male patients with stable coronary artery disease have CAC progression, the main predictors of which are low preoperative cathepsin K level (<16,75 pmol/L) and low bone mineral density (<0,95 g/cm3) according to femoral neck densitometry, as well as a low OPG level (<3,58 pg/ml) 5 years after CABG.

Keywords

• coronary calcification
• coronary artery bypass grafting
• prognosis
• osteo-coronary comorbidity
• biomarkers
• cathepsin k
• osteoprotegerin