The aim of the SMART-CARE trial is to compare clinical outcomes between coronary CT angiography (CCTA) versus standard care as follow-up strategies in high-risk patients after percutaneous coronary intervention (PCI).

Advancements in drug-eluting stents, physiology-guided treatment decisions, intravascular imaging-guided procedural optimization, and adjunctive medical therapy have significantly improved prognosis after percutaneous coronary intervention (PCI). However, high-risk patients-particularly those with complex coronary artery lesions or high-risk clinical conditions such as acute myocardial infarction with or without cardiogenic shock at presentation, diabetes mellitus which requires medical treatment (oral hypoglycemic agents or insulin), end-stage renal disease under dialysis, or multi-vascular disease-continue to have a significantly higher risk of adverse cardiovascular events. In this regard, meticulous follow-up, including periodic assessment of clinical and functional status, guideline-directed medical therapy (GDMT), and secondary prevention strategies are important, and current guidelines strongly recommend these measures as a Class I recommendation. However, recent randomized controlled trials have demonstrated that high-risk patients with complex coronary artery disease or high-risk clinical conditions still experience a continuous increase in adverse cardiovascular events despite optimal secondary prevention. This underscores the need for an optimized surveillance strategy to improve long-term prognosis.

Despite the emphasis on GDMT and secondary prevention in current guidelines, the most effective surveillance strategy after PCI remains uncertain. Existing recommendations primarily address secondary prevention and provide only limited guidance on surveillance for patients with previous coronary revascularization. Based on multiple randomized controlled trials, current guidelines do not recommend routine non-invasive stress testing or coronary CT angiography (CCTA) in asymptomatic patients receiving optimized GDMT (Class III, Level of Evidence B-R). However, this recommendation lacks direct evidence evaluating CCTA as a surveillance strategy after PCI. In patients with prior coronary revascularization, CCTA is currently recommended for assessing bypass graft or stent patency only in symptomatic patients (Class IIa), with limited supporting evidence (Level of Evidence B in ESC guidelines and Level of Evidence B-NR in ACC/AHA guidelines).

Notably, the SCOT-HEART trial demonstrated that a CCTA-based treatment strategy was superior to standard care, which relied on clinical and functional assessment along with as-needed non-invasive stress testing, in reducing a composite outcome of coronary heart disease death and non-fatal myocardial infarction. This suggests that a surveillance strategy incorporating CCTA may lead to improved subsequent management decisions, such as preemptive ischemia-driven revascularization or intensified medical therapy, potentially reducing ischemic cardiovascular events and mortality compared to standard guideline-recommended care.

To address this critical gap in clinical practice, we designed the Smart Angioplasty Research Team-Coronary CT Angiography versus Standard Care as Follow-up Strategies in High-Risk Patients after PCI (SMART-CARE) trial. This study aims to evaluate the impact of a CCTA-based surveillance strategy on clinical outcomes compared with standard guideline-directed follow-up in high-risk patients who have undergone PCI.

Inclusion Criteria:

① Patients aged 19 years old

② Patients who underwent successful PCI with one or more contemporary drug-eluting stents (stent diameter ≥3mm) or drug-coated balloons.

③ Patients must have at least one of the following criteria of complex coronary artery lesions or high-risk clinical characteristics:

A. Complex coronary artery lesions:

i. True bifurcation lesion (Medina 1,1,1/1,0,1/0,1,1) with side branch ≥2.5mm size ii. Chronic total occlusion (≥3 months) as target lesion iii. PCI for unprotected left main (LM) disease (LM ostium, body, distal LM bifurcation including non-true bifurcation) iv. Long coronary lesions (used stents or drug-coated balloons ≥38 mm in length) v. Multi-vessel PCI (≥2 major epicardial coronary arteries treated at one PCI session) vi. Multiple devices needed (≥3 more stents or drug-coated balloons per patient) vii. In-stent restenosis lesion as target lesion viii. Severely calcified lesion (encircling calcium in angiography) ix. Left anterior descending (LAD), left circumflex artery (LCX), and right coronary artery (RCA) ostial lesion

B. High-risk clinical characteristics:

i. Acute myocardial infarction (ST-elevation myocardial infarction [MI] or non-ST-elevation MI) with or without cardiogenic shock (SCAI Classification ≥C) at presentation ii. Diabetes mellitus which requires medical treatment (oral hypoglycemic agents or insulin) iii. End-stage renal disease under dialysis iv. Combined vascular disease other than coronary artery disease

1. Peripheral artery occlusive disease which is defined as A. Previous aorto-femoral bypass surgery, limb bypass surgery, or percutaneous transluminal angioplasty revascularization of the iliac, or infra-inguinal arteries, or B. Previous limb or foot amputation for arterial vascular disease, or C. History of intermittent claudication and one or more of the following: 1) An ankle/arm blood pressure (BP) ratio < 0.90, or 2) Significant peripheral artery stenosis (≥50%) documented by angiography, or by duplex ultrasound, or D. Previous carotid revascularization or asymptomatic carotid artery stenosis ≥50% as diagnosed by duplex ultrasound or angiography.

2. Thoracoabdominal aortic disease which is defined as A. Documented thoracoabdominal aortic aneurysm by duplex ultrasound, angiography, or computed tomography angiography B. Previous endovascular or surgical treatment for thoracoabdominal aortic aneurysm

   ④ Subject who can verbally confirm understandings of risks, benefits and surveillance strategy alternatives of receiving CCTA and he/she or his/her legally authorized representative provides written informed consent prior to any study related procedure.

   Exclusion Criteria:

   ① Advanced chronic kidney disease (Creatinine clearance <30 ml/min/1.73 m2) not on dialysis

   • Known true anaphylaxis to contrast medium (not allergic reaction but anaphylactic shock)

     • Pregnancy or breast feeding ④ Non-cardiac co-morbid conditions are present with life expectancy <1 year or that may result in protocol non-compliance (per site investigator's medical judgment) ⑤ Unwillingness or inability to comply with the procedures described in this protocol.

After publication of first manuscript and trial results, the de-identified data will be shared by permission of principle investigator, when asked.

After publication of first manuscript and trial results, the de-identified data will be shared by permission of principle investigator, when asked.

After publication of first manuscript and trial results, the de-identified data will be shared by permission of principle investigator, when asked.

Participant and care provider cannot be blinded. But, investigator and clinical outcoem assessor will be blinded about the randomly allocated groups. Clinical outcome assessment will be performed under blinded assessment about the allocated treatment group.