Computed Tomography Coronary Angiography Screening of Asymptomatic Patients With Chronic Limb-Threatening Ischaemia at Hospital Discharge: A Randomised Control Trial

Computed Tomography Coronary Angiography + Best Medical Therapy In both arms, each patient will receive an information leaflet which will be created and proofread by the panel of investigators. Arm 1: CTCA Screening + Best Medical Therapy CTCA • Performed within 90 days of hospital discharge, ideally within 30 days. • Scanner specifications: 64-slice multi-detector CT with detector element width 0.625mm with ECG-gating, following SCCT performance guidelines. • Patient preparation: o Rate control with oral beta-blockers targeting heart rate 100kg in accordance with 'As Low as Reasonably Achievable' (ALARA) principles of radiation safety o High-iodine contrast media of 270-400mg iodine/mL as per department protocol o Standard biphasic contrast injection protocols (50-80mL contrast media at 5-7mL/s followed by 40-50mL 0.9% sodium chloride chaser at 5-7mL/s. o Scan performed during inspiration with medium-sized breaths o Reconstructions in standard cardiac planes. o Estimated scan duration of 10-15 minutes however preparation including premedication, cannulation and collection of vital signs may take 30-60 mins. o Reporting using a structured system (e.g. Coronary Artery Disease – Reporting and Data System: CAD-RADS) including segmental stenosis severity (0–5), plaque characteristics and calcium scoring • FFR-CT: o CTCA datasets may be sent for FFR-CT analysis. o Ischaemia-producing lesions defined as FFR-CT <0.80, and severe ischaemia as FFR-CT <0.75 o Absence of FFR-CT will not constitute a protocol deviation. Post-CTCA Management • Lesion management will remain at the discretion of the on-call cardiologist • Recorded therapeutic modifications will include o Initiation or intensification of antiplatelet therapy o Initiation or intensification of lipid-lowering therapy o Initiation or optimisation of anti-hypertensive therapy or beta-blockade o Referral for invasive coronary angiography o Performance of PCI or CABG • Classification of each patient as: o No change in CAD-related management. o Medical therapy intensified only. o Referral for invasive coronary angiography o Underwent endovascular or open coronary revascularisation Best Medical Therapy (BMT) Based upon Australian clinical guidelines for management of cardiovascular disease • High-intensity statin at maximally-tolerated dose (rosuvastatin 20-40mg daily or equivalent) • Antiplatelet therapy (aspirin ± clopidogrel as per clinician) • Blood pressure optimisation, aiming for systolic blood pressure =140mmHg • Angiotensin converting enzyme (ACE) inhibitor or angiotensin-II receptor blocker (ARB), especially in patients with left ventricular ejection fraction (LVEF) <40%, symptoms of heart failure, diabetes, hypertension, and/or chronic kidney disease • Beta-blockers in patients with impaired left ventricular function • Smoking cessation programme referral • Diabetes optimisation aiming for an HbA1c =7.0% Arm 2: Best Medical Therapy Alone BMT will be consistent across both arms Coronary assessment in Arm 2 may occur only if clinically indicated • Development of new chest pain or other symptoms concerning for CAD • Unexplained dyspnoea or exercise intolerance • Preoperative evaluation if indicated prior to major surgery c) who will deliver the intervention BMT will be directed by the admitting vascular team according to the study protocol as above, with the input of other specialist medical services such as endocrinology and cardiology, CTCA will be performed within the referring institution or its tertiary referral service to ensure consistency in imaging protocol d) the mode of delivery BMT will be prescribed during inpatient admission and compliance monitored during outpatient follow up CTCA will also be organised for the patient during their admission by the vascular surgery team. e) the number of times the intervention will be delivered and over what period of time Patients will have their BMT optimised in hospital and have one postoperative CTCA. f) the location/setting where the intervention occurs The BMT prescription will be given at the admitting institution. The CTCA as stated above will be performed in the institution where the patient was admitted, or its corresponding tertiary referral unit. g) any strategies used to assess or monitor adherence or fidelity to the intervention Patients will be followed up within the department's vascular surgery outpatient clinic. Their compliance will be monitored at each visit. Following CTCA - the reports will be sent to an interventional cardiologist. We aim to recruit an interventional cardiologist to our study panel.