Myocardial ischemia in nonobstructive coronary arteries: A review of diagnostic dilemmas, current perspectives, and emerging therapeutic innovations

Table 7 Biomarkers involved in coronary artery spasm and coronary microvascular dysfunction

Biomarker	Description	Clinical significance
CRP	CRP is a marker of systemic inflammation, and elevated levels indicate ongoing inflammation, which may contribute to CAS and CMD	Elevated CRP levels are associated with poor prognosis in MINOCA, reflecting chronic inflammation and vascular dysfunction
IL-6	IL-6 is a pro-inflammatory cytokine that plays a central role in inflammatory responses and vascular injury. Elevated IL-6 levels are linked with CMD and spasms	High IL-6 levels indicate an inflammatory state, which can exacerbate CMD and increase the risk of MINOCA
Lp(a)	Lp(a) is an atherogenic lipoprotein that can contribute to endothelial dysfunction, promoting both CAS and CMD	Lp(a) is higher in patients with spastic sites of coronary arteries
Rho-associated protein kinase	Rho kinase activates myosin light chain kinase through phosphorylation. Rho kinase thus regulates smooth muscle contraction and endothelial function. It is involved in coronary artery spasm and microvascular dysfunction	Increased Rho kinase activity is linked with impaired vasodilation and increased vasoconstriction, contributing to CAS and CMD in MINOCA

CRP: C-reactive protein; IL-6: Interleukin 6; Lp(a): Lipoprotein (a); CAS: Coronary artery spasm; CMD: Coronary microvascular dysfunction; MINOCA: Myocardial infarction with nonobstructive coronary arteries.