N-Terminal Pro-B–Type Natriuretic Peptide Is Related to Retinal Microvascular Damage

An important cornerstone in cardiovascular research has been the identification of markers that not only relate to clinical disease but are also indicative of subclinical disease. In recent years, N-terminal pro-B–type natriuretic peptide (NT-proBNP) has emerged as such a marker, associated in particular with heart failure. NT-proBNP is a biologically inactive metabolite secreted together with its biologically active counterpart BNP from cardiac myocytes in response to cardiac stress. Typically, studies have measured NT-proBNP instead of BNP, given its lower cost and easier availability of assays. Importantly, NT-proBNP is not only informative about clinically overt heart failure but is also increased in participants with subclinical cardiac dysfunction. Given the strong link between cardiac disease and large vessel disease, studies have also shown NT-proBNP to be related to various indices of large vessel disease, such as coronary atherosclerosis, carotid-pulse wave velocity, aortic valve disease, and aortic stenosis. Although cardiac disease has a substantial component due to large vessel disease, nevertheless, ≤40% of patients with symptoms of cardiac ischemia have normal arteries on coronary angiography. Observations primarily from cardiac imaging studies have indeed demonstrated that these patients have impaired myocardial blood flow and coronary flow reserve despite normal coronary arteries, pointing toward other mechanisms of cardiac ischemia. Currently,