Cold-Region Exposure and Cardiac Remodeling After PCI

Cold exposure has been associated with an increased risk of cardiovascular morbidity and mortality in population-based epidemiological studies. However, limited evidence is available regarding whether chronic cumulative exposure to cold environments is associated with myocardial structural and functional abnormalities or adverse prognosis among patients who have undergone coronary revascularization.

The COLD-PCI Study is a multicenter prospective observational cohort study designed to characterize the relationship between chronic cold-region exposure, cardiovascular imaging phenotypes, left ventricular remodeling, and subsequent cardiovascular outcomes after successful percutaneous coronary intervention.

The primary environmental exposure will be cumulative cold-region exposure during the 3 years preceding PCI. Exposure histories will be obtained using a standardized Cold Exposure History Questionnaire documenting residential, occupational, training/deployment, and relevant travel histories. Geographic locations will be coded at the county level. Months with at least 15 days of residence or work in a predefined cold region will be counted toward cumulative exposure.

Participants will be categorized into three exposure strata: no/minimal exposure (<6 months), short-term exposure (6 to <18 months), and long-term exposure (≥18 months). Objective meteorological exposure will additionally be assessed by linking participants' geographic histories to daily meteorological records and calculating the number of regional cold-wave days. Winter outdoor occupational exposure will also be quantified.

Baseline CMR will be performed approximately 7-14 days after PCI to characterize ventricular volumes and function, myocardial strain, left ventricular mass, myocardial infarct characteristics, microvascular obstruction, and other available myocardial tissue characteristics. Baseline transthoracic echocardiography will be performed within 3 days of CMR. Twelve-lead electrocardiographic parameters and routine demographic, clinical, angiographic, biochemical, and treatment variables will also be collected.

Follow-up echocardiography will be performed at 6 months. The primary outcome is adverse left ventricular remodeling, defined as an increase of at least 20% in left ventricular end-diastolic volume from baseline to the 6-month examination. Participants will additionally undergo longitudinal follow-up for major adverse cardiovascular events.

The study will examine associations between cumulative cold-region exposure and CMR phenotypes, evaluate potential imaging mediators of adverse ventricular remodeling, and assess whether cold-exposure variables improve prognostic prediction beyond conventional clinical, CMR, and electrocardiographic markers.

Inclusion criteria

• Age 18 to 75 years. Angiographically confirmed coronary artery disease treated with successful percutaneous coronary intervention, defined as residual stenosis <30% with final TIMI grade 3 flow.

Clinically stable after PCI. Expected survival of at least 12 months. Able and willing to undergo baseline cardiovascular magnetic resonance imaging and baseline and 6-month transthoracic echocardiography.

Able to provide residential, occupational, training/deployment, and other relevant exposure histories for the 3 years preceding PCI.

Written informed consent provided.

Exclusion criteria

• Severe valvular heart disease, cardiomyopathy, congenital heart disease, or other major structural heart disease.

Previous coronary artery bypass grafting or heart transplantation. End-stage heart failure or New York Heart Association class IV heart failure. Severe renal dysfunction, defined as estimated glomerular filtration rate <30 mL/min/1.73 m².

Known contraindication to cardiovascular magnetic resonance imaging or gadolinium-based contrast agents.

Inability to complete transthoracic echocardiographic assessment. Inability to reliably recall or verify major residential or occupational exposure history during the 3 years preceding PCI.

More than five major changes in primary residence during the 3 years preceding PCI that preclude reliable estimation of cumulative cold-region exposure.