[Relationship between the subendocardial viability ratio and risk factors for ischemic heart disease]

Research Progress and Clinical Value of Subendocardial Viability Ratio

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.

Subendocardial Viability Ratio Predictive Value for Cardiovascular Risk in Hypertensive Patients

Background: The subendocardial viability ratio (SEVR), also known as the Buckberg index, is a parameter of arterial stiffness with indirect prognostic value in assessing long-term cardiovascular risk. Materials and Methods: We conducted a prospective cohort study on 70 patients with uncomplicated hypertension admitted to a county medical reference hospital. We analyzed demographics, laboratory data, arterial stiffness parameters and cardiovascular risk scores (SCORE and Framingham risk scores) and aimed to identify paraclinical parameters associated with increased cardiovascular risk. Results: Of the arterial stiffness parameters, SEVR correlates statistically significantly with age, central and peripheral systolic blood pressure, as well as with heart rate. SEVR seems to have prognostic value among hypertensive patients by increasing the risk of major cardiovascular events assessed by SCORE and Framingham risk scores. SEVR correlates statistically significantly with serum fibrinogen (p = 0.02) and hemoglobin (p = 0.046). Between pulse wave velocity and lipid parameters (p = 0.021 for low-density lipoprotein cholesterol <LDL> and p = 0.030 for triglycerides) a statistically significant relationship was found for the study group. The augmentation index of the aorta also correlated with serum LDL-cholesterol (p = 0.032) and the hemoglobin levels (p = 0.040) of hypertensive patients. Conclusions: Age, abdominal circumference and Framingham score are independent predictors for SEVR in our study group, further highlighting the need for early therapeutic measures to control risk factors in this category of patients.

Arterial Stiffness in Renal Transplant Recipients: 5-Year Follow-up

BACKGROUND

Chronic kidney disease is a risk factor for cardiovascular diseases. After renal transplant, some traditional and chronic kidney disease-specific risk factors vanish, but new risk factors emerge. This retrospective study aimed to define the long-term impact of renal transplant and diabetes mellitus on arterial stiffness, evaluated by measuring pulse wave velocity (PWV) and augmentation index (AI) and on myocardial perfusion, evaluated by subendocardial viability ratio (SEVR).

METHODS

PWV, AI, and SEVR were evaluated noninvasively by applanation tonometry using SphygmoCor in the first 4 weeks after kidney transplant and 4 to 5 years thereafter.

RESULTS

A total of 48 graft recipients (18 women, 30 men; mean ± standard deviation age, 47.9 ± 11.8 years) were included. The follow-up period was 57.4 ± 8.0 months. PWV did not change significantly during the follow-up period (9.1 ± 1.8m/s and 8.7 ± 1.8m/s, respectively; P = .137). In the subgroup of patients without diabetes mellitus, we observed a trend of PWV reduction, whereas in the subgroup of patients with diabetes we observed the trend of PWV increase. The duration of smoking before transplant correlated significantly with PWV (P = .012). AI in the whole group increased significantly during the study period (from 18.3% ±10.3% to 25.9% ±9.4%; P < .01) as well as SEVR (from 134.9 ± 23.1 to 155.4 ± 28.6; P = .001).

CONCLUSIONS

PWV, reflecting the central vessel stiffness, did not change significantly in the whole group during the follow-up period. The AI, which indicates systemic stiffness, increased significantly within 5 years after transplant, indicating the progression of vascular processes of elastic and muscular arteries. Significant increases in the SEVR values in both diabetics and nondiabetics indicate the long-term favorable effect of kidney transplant on myocardial perfusion.

Impaired subendocardial perfusion in patients with metabolic syndrome

BACKGROUND

Metabolic Syndrome (MS) is associated to vascular damage, increased arterial stiffness, and impaired myocardial perfusion. Subendocardial viability ratio (SEVR) is a noninvasive estimation of myocardial workload, oxygen supply, and perfusion. The aim of the study was to describe the relation between arterial stiffness, SEVR, and cardio-metabolic risk factors.

METHODS

A cohort of 55 patients, aged 59.9 ± 10.8 years, was studied; 28 subjects (50.9%) had metabolic syndrome. All patients underwent a clinical evaluation and blood venous sampling, to assess glico-lipid profile. Applanation tonometry was performed, to obtain pulse wave analysis and SEVR values.

RESULTS

In the overall study population, SEVR showed negative associations with mean (r = -0.301; p = 0.026) and systolic (borderline relation, r = -0.257; p = 0.058) arterial pressure. Metabolic syndrome patients presented lower level of SEVR (p = 0.012), even after adjusting for age, sex, and mean arterial pressure (p = 0.040). Subdividing the study population by the number of metabolic syndrome components, SEVR significantly decreased as the number of Metabolic Syndrome components increased (p for trend 0.005). In a logistic backward regression analysis, both metabolic syndrome and mean arterial pressure resulted significant predictors of SEVR, accounting for 18% of variance.

CONCLUSION

The reduced SEVR in metabolic syndrome patients could be an important pathophysiological determinant of the increased cardiovascular risk.

Vascular effects of combined enriched Korean Red ginseng (Panax Ginseng) and American ginseng (Panax Quinquefolius) administration in individuals with hypertension and type 2 diabetes: A randomized controlled trial

BACKGROUND

Type 2 diabetes is known to abrogate the vascular response. Combination of two commonly consumed ginseng species, American ginseng (AG) and a Korean Red ginseng (KRG), enriched with ginsensoide Rg3, was shown to concomitantly improve glucemic control and blood pressure. We evaluated the hypothesis that improvements in central hemodynamics, vascular function and stiffness markers are involved in observed benefits of co-administration.

METHODS

In this randomized, placebo controlled, two-center trial, patients with type 2 diabetes and hypertension were assigned to either 2.25 g ginsenoside Rg3-enriched KRG&AG co-administration or a control 3 times daily for 12-weeks, treated by standard of care. The effects on central hemodynamics, pulse wave velocity (PWV) and endothelial function over the 12-week administration were analyzed.

RESULTS

In intent-to-treat analysis of 80 individuals, a reduction in central systolic BP (-4.69 ± 2.24 mmHg, p = 0.04) was observed with co-administration of Rg3-KRG + AG relative to control at 12-weeks, which was characterized by a decrease in end-systolic pressure (-6.60 ± 2.5 mmHg, p = 0.01) and area under the systolic/diastolic BP curve (-132.80 ± 65.1, p = 0.04, 220.90 ± 91.1, p = 0.02, respectively). There was no significant change in reactive hyperemia index (0.09 ± 0.11, p = 0.44), PWV (-0.40 ± 0.28 %, p = 0.17), and other related pulse wave analysis components.

CONCLUSION

Co-administration of complementary ginseng species improved central systolic BP and components of pulse waveform without a direct effect on endothelial function, when added to background pharmacotherapy in individuals with diabetes. These data support potential utility of ginseng for modest blood pressure benefit to broaden its role in diabetes management.

A cross-section study of main determinants of arterial stiffness in Hefei area, China

BACKGROUND

Arterial stiffness has emerged as an independent risk factor for adverse cardiovascular disease events and is the consequence of multiple risk factors. The aim of the present study is to explore the main determinants of arterial stiffness in a Chinese population and to study how the arterial stiffness levels affected by different number of risk factors.

METHODS

This study included 358 subjects in Hefei area of China. Anthropometric indexes, biochemical indexes, cardiovascular function indexes and lifestyle were achieved. Brachial-ankle pulse wave velocity (baPWV) was used to assess arterial stiffness. Multivariate linear regression model was performed to identify the main determinants of arterial stiffness levels.

RESULTS

baPWV was correlated with age, sex, hypertension, various blood pressure components (systolic blood pressure [SPB], diastolic blood pressure, pulse pressure, and central arterial pressure), serum lipids, fasting blood-glucose and body mass index, subendocardial viability ratio (SEVR) and ejection duration (ED) in bivariate correlation analysis. Moreover, baPWV was only positively correlated with age, hypertension and SBP and inversely correlated with SEVR and ED in multivariable regression model. These five variables explained about 74.8% variances of baPWV and age was the strongest determinant of arterial stiffness. In addition, the levels of arterial stiffness increased with the augmented number of risk factors when the total number of factors was no more than 4.

CONCLUSIONS

The main determinants of arterial stiffness were age, hypertension, SBP, SEVR and ED. Furthermore, the number of risk factors had an independent influence on arterial stiffness, it is of great importance to consider the number of risk factors when it comes to cardiovascular risk assessment.

Hemodynamic and hormonal patterns of untreated essential hypertension in men and women

BACKGROUND

Knowledge of hemodynamic factors accounting for the development of hypertension should help to tailor therapeutic approaches and improve blood pressure control. Few data exist regarding sex differences of hemodynamic factors contributing to hypertension progression among patients with untreated nondiabetic stage I and II prehypertension (PreHyp) as defined by the Joint National Committee-7 guidelines (JNC-7).

METHODS

We utilized noninvasive impedance cardiography, applanation tonometry and plasma measures of angiotensin II, angiotensin (1-7), serum aldosterone, high-sensitivity C-reactive protein (hs-CRP) and cytokine biomarkers of inflammation to characterize the hemodynamic and hormonal profile of 100 patients with untreated hypertension (39 women).

RESULTS

Despite there being no differences between women and men in terms of office blood pressure, heart rate and body mass index, men demonstrated lower values of pulse pressure, systemic vascular resistance, brachial artery pulse wave velocity and augmentation index. In each of the three hypertension categories, the increased blood pressure in men was associated with significant augmentations in stroke volume and cardiac output compared with women. Sex-related hemodynamic differences were associated in women with higher plasma levels of leptin, hs-CRP, plasma angiotensin II and serum aldosterone, and no differences in the serum concentrations of cytokinins. In women but not men, hs-CRP correlated with plasma concentrations of transforming growth factor β1 (TGFβ1) and body weight; in addition, plasma TGFβ1 correlated with levels of serum vascular cell adhesion molecule 1.

CONCLUSION

The impact of sex differences in the hemodynamic factors accounting for the elevation in arterial pressure in subjects with essential hypertension has been poorly characterized or this information is not available. We suggest that this gap in knowledge may adversely influence choices of drug treatment since our study shows for the first time significant differences in the hemodynamic and hormonal mechanisms accounting for the increased blood pressure in women compared to men.

Predictors of contractile recovery after revascularization in patients with anterior myocardial infarction who received thrombolysis

BACKGROUND

Identification of viable myocardium after myocardial infarction has gained paramount importance with the current progress in coronary revascularization.

OBJECTIVE

To explore the prognostic power of certain patient characteristics to predict myocardial contractile recovery after revascularization in patients presenting with acute anterior ST elevation myocardial infarction (STEMI) who received thrombolytic therapy.

METHODS

Seventy-three consecutive patients presenting with first acute anterior STEMI who had received thrombolytic therapy and had significant coronary stenosis or occlusion of the infarct-related artery amenable for revascularization were enrolled. All patients underwent echocardiographic assessment of regional wall motion and left ventricular ejection fraction. Patients underwent coronary revascularization by either percutaneous angioplasty or surgical bypass. Echocardiography was repeated two to three months following revascularization. Patients were classified into two groups: group 1 had evidence of contractile recovery after revascularization at follow-up echocardiography and group 2 had no such evidence of recovery.

RESULTS

Predictors of contractile recovery after revascularization included a shorter time from symptom onset to the institution of thrombolytic therapy, a lower baseline wall motion score index, the presence of grade 3 collaterals to the infarct-related artery and the use of beta-blockers. Instead, the presence of diabetes mellitus and a totally occluded infarct-related artery predicted poor contractile recovery.

CONCLUSIONS

Myocardial contractile recovery after revascularization in patients presenting with first acute anterior STEMI may be predicted by the absence of diabetes, a shorter time from symptom onset to thrombolytic therapy, the use of beta-blockers, a lower initial wall motion index score and the presence of collaterals to the infarct-related artery.