Using a prospective cohort study design, this study will enroll patients with clinical indications scheduled for invasive coronary angiography and coronary functional assessment. With a two-tiered framework of "pre-intervention baseline exposure assessment + procedural contamination quantification", it will be the first study to systematically evaluate the dose-response relationship between circulating microplastics and nanoplastics (MNPs) levels and coronary microvascular dysfunction (CMD). Through 2 years of follow-up, the effect of MNPs on the long-term prognosis of patients with CMD will also be assessed.
Multi-modal omics technologies including pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), laser direct infrared spectroscopy (LDIR), and scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS) will be applied for the qualitative and quantitative detection of MNPs. The index of microcirculatory resistance (IMR) and coronary flow reserve (CFR), measured via the invasive thermodilution method recommended by the European Society of Cardiology (ESC), will be used to define and evaluate CMD.
The core innovations of this protocol are twofold:
The key blood samples for exposure measurement are strictly collected before any medical procedures are performed after admission, to maximally eliminate the confounding bias from iatrogenic interference in baseline MNPs exposure quantification.
A three-level blank quality control system (procedural blank, environmental blank, device blank) is established to realize full-process monitoring and quantification of iatrogenic contamination.
The entire study design strictly adheres to current technical recommendations and industry consensus in clinical practice, and demonstrates high feasibility, reproducibility, and reliability.