The Anti-Anginal effect of Zinc in Angina with Non-Obstructive Coronary Arteries (ANOCA) Patients

In 30% of patients with angina, angiography does not reveal obstructive coronary artery disease and the myocardial ischaemia may arise from large vessel coronary artery spasm (vasospastic angina) or coronary microvascular dysfunction (microvascular angina). Collectively, these patients are labelled as ANOCA (Angina with Non Obstructive Coronary Arteries) with 1,800 patients/year being afflicted within South Australia. These patients are significantly disabled with an impaired quality of life and have limited available effective therapies, except for calcium channel blockers in vasospastic angina. There is a need to develop novel therapies that effectively target coronary vasomotor dysfunction. Zinc (Zn), an essential micronutrient, is critical to the functioning of many metalloenzymes and transcription factors. Deficiency of Zn can exacerbate or complicate disease in multiple organ systems. We have demonstrated the importance of Zn homeostasis for the vasculature, including potentiating vasodilator responses via the nitric oxide production and inhibiting endothelin-1-induced constriction. We have recently conducted the first systematic study in Australian cardiac patients, showing a high prevalence of Zn deficiency (29%, n = 400), associated with worse disease. This study is a randomised, double-blind, placebo-controlled crossover study assessing the anti-anginal benefits and impact on health status of Zn 30mg once daily in ANOCA patients experiencing angina at least 3 times/week.