Research Progress and Clinical Value of Subendocardial Viability Ratio

Abstract

Cardiovascular disease remains the leading cause of morbidity and mortality worldwide, with ischemic heart disease being a major contributor, either through coronary atherosclerotic plaque-related major vascular disease or coronary microvascular dysfunction. Obstruction of coronary blood flow impairs myocardial perfusion, which may lead to acute myocardial infarction in severe cases. The subendocardial viability ratio, also known as the Buckberg index, is a valuable tool for evaluation of myocardial perfusion because it reflects the balance between myocardial oxygen supply and oxygen demand. The subendocardial viability ratio can effectively evaluate the function of the coronary microcirculation and is associated with arterial stiffness. This ratio also has potential value in predicting adverse cardiovascular events and mortality in various populations. Moreover, the subendocardial viability ratio has demonstrated clinical significance in a range of diseases, including hypertension, aortic stenosis, peripheral arterial disease, chronic kidney disease, diabetes, and rheumatoid arthritis. This review summarizes the applications of the subendocardial viability ratio, its particular progress in the relevant research, and its clinical significance in cardiovascular diseases.

Keywords: cardiovascular disease; ischemic heart disease; myocardial oxygen supply and demand; myocardial perfusion; subendocardial viability ratio.

Figure 1. Measurement, affecting factors, and clinical value of the subendocardial viability ratio (SEVR).

Figure 2. Three methods for measurement of the subendocardial viability ratio (SEVR).

SEVR=diastolic pressure time index (DPTI)/systolic pressure time index (SPTI). DPTI and SPTI are, respectively, the areas of blue and yellow in the figure. A, Invasive method. The DPTI is the area between the diastolic aortic pressure curve and the left ventricular (LV) pressure curve, and the SPTI is the area under the systolic LV pressure curve. B, Traditional noninvasive method. The DPTI is the area under the systolic central artery pressure curve, and the SPTI is the area under the systolic central artery pressure curve. C, New noninvasive method. The DPTI is the area under the central pressure curve in diastole minus the estimated isovolumic systolic and isovolumic diastolic LV pressure and LV filling pressure, and the SPTI is the area under the central arterial pressure curve in diastole and isovolumic systole. ICT indicates isovolumic contraction time; IRT, isovolumic relaxation time; and LVET, left ventricular ejection time.