Relationship between subendocardial viability ratio and cardiovascular disease risk in hypertensive patients

Background: The subendocardial viability ratio (SEVR), which correlates with coronary flow reserve, has been proposed as an indirect prognostic marker for cardiovascular disease (CVD). This study aimed to investigate the relationship between SEVR and cardiovascular risk scores, and to evaluate its value in identifying increased cardiovascular risk in hypertensive population. Methods: A total of 1,380 participants (782 hypertensive patients and 598 normotensive controls) were enrolled. Demographic characteristics, laboratory parameters, arterial stiffness, left ventricular structural and functional indices, and 10-year atherosclerotic CVD (ASCVD) risk calculated via the China Atherosclerotic CVD Risk Prediction model (China-PAR) were collected and analyzed. Multivariable linear regression and logistic regression analyses were conducted to identify independent determinants of SEVR and factors linked to high ASCVD risk (>10%). Results: Mean SEVR was significantly lower in the hypertensive group than in the control group (130.75% vs. 136.38%, P<0.001). SEVR was negatively correlated with age, heart rate (HR), systolic blood pressure (SBP), E/e' ratio, arterial velocity index, and arterial pressure-volume index (all P<0.001). Multivariable linear regression identified age (β=−0.106, P=0.001), HR (β=−0.618, P<0.001), SBP (β=0.024, P=0.023), arterial pressure volume index (API) (β=−0.338, P<0.001), and hemoglobin (β=0.219, P=0.001) as independent determinants of SEVR. Logistic regression (Model 2, adjusted for sex, smoking, SBP, and HR) showed that SEVR was independently associated with a 10-year ASCVD (10Y-ASCVD) risk >10% [odds ratio (OR) =0.953, 95% confidence interval (CI): 0.940–0.965, P<0.001]. Male sex (OR =1.973, P=0.001), current smoking (OR =2.665, P=0.001), and SBP (OR =1.015, P=0.003) were significant risk factors, while HR was protective (OR =0.949, P<0.001). In risk stratification, the high-risk group (10Y-ASCVD risk >10%) had significantly lower SEVR than the low-risk group in both hypertensive (122.72% vs. 131.92%, P<0.05) and control subjects (123.91% vs. 137.67%, P<0.05). Receiver operating characteristic analysis revealed that SEVR identified high ASCVD risk with an area under the curve of 0.706 in controls and 0.630 in hypertensives. Conclusions: SEVR is inversely associated with 10Y-ASCVD risk in individuals with hypertension and remains an independent indicator after adjustment for conventional risk factors. As a noninvasive and cost-effective marker reflecting myocardial oxygen supply-demand balance, SEVR has the potential to add complementary value to current cardiovascular risk assessment models, thereby refining risk stratification in patients with hypertension.