Table 2.

circRNAs as potential biomarkers

CircRNA	CVD category	Findings of the study	Methods	Reference
Hsa_circ_0001445	Coronary Atherosclerosis	Hsa_circ_0001445 was remarkably stable in plasma. Plasma levels of hsa_circ_0001445 were proportional to coronary atherosclerotic burden and improved detection of coronary artery atherosclerosis.	RT-qPCR in plasma from 200 patients with suspected stable CAD.	Vilades et al 2020 [12]
Hsa_circ_0001879 and Hsa_circ_0004104	CAD	Both significantly upregulated in CAD patients. Overexpression of hsa_circ_0004104 in vitro resulted in dysregulation of atherosclerosis-related genes	Microarray and RT-qPCR in whole blood from 24 CAD patients and 7 healthy controls. Further verified by qPCR in 412 CAD patients and 290 controls	Wang et al 2019 [98]
Hsa_circ_0124644	CAD	First study to investigate the circRNA profile in the peripheral blood of CAD patients. Circulating levels of hsa_circ_0124644 improved detection of CAD.	Microarray in peripheral blood from 12 CAD patients and 12 healthy controls. qPCR of 5 circRNAs with highest fold change in 30 controls and 30 CAD patients. Validation in 137 CAD patients and 115 healthy controls	Zhao et al 2017 [101]
Hsa_circ_0005540	CAD	Hsa_circ_0005540 was significantly associated with CAD.	RNA Sequencing of circRNA expression levels in plasma exosomes. CAD patients (n = 61) and non-CAD controls (n = 38) formed the profiling and internal validation phases. CAD (n = 47) patients and non-CAD controls (n = 51) for the validation phase.	Wu et al 2020 [99]
Myocardial Infarction-Associated Circular RNA (MICRA)	Myocardial Infarction	Circulating levels of MICRA were lower in MI patients. MICRA was a strong predictor of left ventricle (LV) dysfunction; patients with lower levels of MICRA were at higher risk of LV dysfunction	RT-qPCR in whole blood from 642 acute MI patients, 86 heathy controls	Vausort et al 2016 [96]
Myocardial Infarction-Associated Circular RNA (MICRA)	Myocardial Infarction	MICRA classified patients into ejection fraction (EF) groups. Improved risk classification after MI	RT-qPCR in whole blood from 472 acute MI patients classified into 3 groups according to ejection fraction	Salgado-Somoza et al 2017 [97]
CircHIPK3	Myocardial Infarction	Exosomal circHIPK3 released from hypoxia-induced cardiomyocytes regulates cardiac angiogenesis after MI	Hypoxic cardiomyocytes released circHIPK3-rich exosomes to regulate oxidative stress damage in cardiac endothelial cells. Angiogenesis following MI in mice was promoted.	Wang et al 2020 [100]