Ankle –branchial index (ABI)
When detecting CAVI and ba-PWV, the value of ABI will be detected respectively. In this study, we will analyze the differences between the two kinds of ABI.
Carotid ultrasound detection
Carotid intima-media thickness (CIMT) and plaque are assessed with ultrasound (VIVID E80, GE, USA) with a connected electrocardiogram. The whole extracranial carotid artery was scanned by longitudinal and cross-sectional two-dimensional (2D) B-mode image, including common carotid artery, bifurcation of common carotid artery (CCA), extracranial segment of internal carotid artery (ICA) and extracranial segment of extracranial carotid artery (ECA) according to the Mannheim Carotid Intima-Media Thickness and Plaque Consensus13 .
CIMT is a double-line pattern visualized by echography on both walls of the CCA in a longitudinal image. Two parallel lines, which consist of the leading edges of two anatomical boundaries, form it: the lumen-intima and media-adventitia interfaces13. Edge detection system is used for semi-automatic measurements performed on a 10-mm segment of CCA instantaneously. Using the semi-automatic measurement software, the sampling frame was sampled at 1cm in two-dimensional mode and measured the posterior wall at the bifurcation of the common carotid artery and 1cm from the bifurcation of the common carotid artery. Measurement of CIMT should occur within a region free of plaque with a clearly identified double-line pattern in diastole on the selected frame. The measurement parameters include the average value of CIMT, the maximum value of CIMT, the minimum value of CIMT, the standard deviation of CIMT and the number of successful CIMT measurements. CIMT ≥ 1.0 mm is defined as thickening.
Plaques are focal structures encroaching into the arterial lumen of at least 0.5 mm or 50% of the surrounding CIMT value, or demonstrates a thickness >1.5 mm as measured from the intima-lumen interface to the media-adventitia interface from 2 different angles of insonation, in longitudinal and cross-sectional views13.
The evaluation of carotid stenosis will be combined with the results of vascular diameter and area measurement and hemodynamic parameters. A peak systolic velocity (PSV) of less than 125 cm/s corresponds to lower than 50% stenosis; of 125-230 cm/s corresponds to 50%-69% stenosis; and one of more than 230 cm/s corresponds to greater than 70% stenosis14, 15. The intravascular diameter method was used to evaluate the carotid stenosis using the European Carotid Surgery Trial (ECST), that is, the ratio of the residual diameter of the stenosis to the original diameter of the stenosis. The area method evaluates the stenosis rate as the area stenosis rate = [1-(minimum lumen cross-sectional area / original lumen cross-sectional area)] x100%.
End points and assessment
The primary outcome will be the incidence of MACEs.
MACEs include all cause death, cardiovascular death, non-cardiovascular death, undetermined cause of death, myocardial infarction (MI), hospitalization for unstable angina (UA), transient ischemic attack (TIA) and stroke, heart failure (HF) event, percutaneous coronary intervention (PCI), coronary artery bypass grafting (CABG), peripheral vascular intervention (PVI), stent thrombosis16.
Cardiovascular death includes acute MI, sudden cardiac death, heart failure, stroke, cardiovascular procedure and cardiovascular hemorrhage etc.
Definition of MI is clinical syndrome where there is evidence of myocardial necrosis in a clinical setting consistent with acute myocardial ischemia, including presence of acute symptoms of myocardial ischemia, such as chest, upper extremity, mandibular, or epigastric discomfort, or an ischemic equivalent such as dyspnea or fatigue; presence of new or presumed new significant ST-segment–T wave (ST-T) changes or new left bundle-branch block (LBBB) consistent with acute myocardial ischemia; presence of new or presumed new pathological Q waves consistent with MI; presence of thrombus in a major epicardial vessel consistent with an acute MI; demonstration of a new change in myocardial viability or function consistent with MI; occurrence of an adverse angiographic finding during PCI consistent with acute myocardial ischemia; angiographic documentation of a new CABG or new native coronary artery occlusion within 48 h of CABG surgery; cardiac biomarker level16.
Definition of hospitalization for UA include unscheduled hospitalization for the management of UA, occurring within 24 h of the most recent symptoms. Hospitalization is defined as an admission to an inpatient unit or a visit to an emergency department (ED) that results in at least a 24-h stay (or a change in calendar date if the hospital admission or discharge times are not available) 16.
Stroke is defined as an acute episode of focal or global neurological dysfunction caused by brain, spinal cord, or retinal vascular injury as a result of hemorrhage or infarction. Categorical description of stroke type classified into 1 of 3 mutually exclusive categories (ischemic, hemorrhagic, undetermined) 16.
TIA is defined as transient episode of focal caused by brain, spinal cord, or retinal ischemia without acute infarction16.
HF event is defined as presentation of the patient for an urgent, unscheduled clinic/office/ED visit or hospital admission, with a primary diagnosis of HF, where the patient exhibits new or worsening symptoms of HF on presentation, has objective evidence of new or worsening HF, and receives initiation or intensification of treatment specifically for HF16.
PCI is the placement of an angioplasty guidewire, balloon, or other device (eg. stent, atherectomy, brachytherapy, or thrombectomy catheter) into a native coronary artery or CABG
for the purpose of mechanical coronary revascularization16.
CABG surgery is a procedure performed to bypass partially or completely occluded coronary arteries with veins and/or arteries harvested from elsewhere in the body, thereby improving the blood supply to the coronary circulation supplying the myocardium (heart muscle)16.
A PVI is a catheter-based or open surgical procedure designed to improve arterial or venous blood flow or otherwise modify or revise vascular conduits. Procedures may include, but are not limited to, percutaneous transluminal balloon angioplasty, stent placement, thrombectomy, embolectomy, atherectomy, dissection repair, aneurysm exclusion, treatment of dialysis conduits, placement of various devices, intravascular thrombolysis or other pharmacotherapies, and open surgical bypass or revision16.