Central pulse pressure amplification is associated with more extensive and severe coronary artery disease

Viewpoint: The Case for Non-Invasive Central Aortic Pressure Monitoring in the Management of Hypertension

Elevated central aortic pressure indices (e.g., systolic pressure and pulse pressure) predict cardiovascular (CV) events and mortality in addition to structural changes (e.g., left ventricular hypertrophy, carotid intima-media thickness and reduced glomerular filtration rate). These elevated risks have been shown in multiple studies to be superior to, and in others, at least as high as that associated with brachial pressures. Threshold values for the diagnosis of elevated central arterial pressures have been defined and can be considered target goals of treatment. Measurements of central arterial pressures can be incorporated into the current approaches to hypertension management utilizing currently available non-invasive devices that measure central pressures during the measurement of brachial BP. The objective of this review is to outline the rationale and evidence supporting incorporation of central aortic pressure monitoring into the care of patients with hypertension.

Pulsatile Hemodynamics and Coronary Artery Disease

Coronary artery disease (CAD) is the leading cause of human death and has a high prevalence throughout the world. Therefore, it is important to detect CAD early and to apply individualized therapy according to the patients' risk. There is an increasing interest in pulsatile arterial hemodynamics in the cardiovascular area. Widely used measurements of arterial pulsatile hemodynamics include pulse pressure, pulse wave velocity and augmentation index. Here, we will review underlying pathophysiology linking the association of arterial pulsatile hemodynamics with CAD, and the usefulness of the measurements of pulsatile hemodynamics in the prediction of future cardiovascular events of CAD patients. Clinical and therapeutic implications will be also addressed.

Impact of coronary artery disease on augmentation index as measured by estimated central blood pressure: A case control study in Asian Indians

Aims

We compared various components of blood pressure and arterial stiffness of healthy control with those of coronary artery disease (CAD) patients using BP+ machine™.

Methods

In this prospective, case-control study, total 585 individuals of both the genders were enrolled. The study population consisted of 277 controls (healthy siblings of diseased subjects not having CAD – group A) and 308 CAD patients (group B). Age and sex adjusted regression and receiver operative curve (ROC) analysis was performed to assess the strength of association of these parameters.

Results

We found that mean systolic blood pressure (SBP) (137.14 ± 22.49 vs. 129.26 ± 19.86), central systolic blood pressure (CSBP) (130.78 ± 21.89 vs. 117.53 ± 17.98), augmentation index (AI) (108.55 ± 44.98 vs. 49.38 ± 21.03) and pulse rate variability (98.82 ± 231.09 vs. 82.86 ± 208.77) were significantly (p < 0.05) higher in CAD population as compared to healthy counterparts. Left ventricular contractibility as measured by dP/dt was significantly lower in CAD patients. All these parameters were significantly abnormal in CAD as compared to healthy control population irrespective of the gender of the patient except for SBP in females. Both – odds ratio (1.108; 95% CI: 1.081–1.135; p < 0.0001) and ROC analysis (AUC: 0.937; 95% CI: 0.919–0.956; p < 0.0001) showed AI as the strongest predictor of CAD, closely followed by CSBP.

Conclusion

Central aortic blood pressure parameters such as AI and CSBP measured noninvasively with BP+ machine could be the effective predictors of CAD in Asian Indians.

Type 2 diabetes compromises the value of non-invasively measured augmentation index in predicting the severity of coronary artery disease: a hospital-based observational study

Background

Central hemodynamic indices have been demonstrated to correlate with coronary artery disease (CAD). However, in the context of type 2 diabetes mellitus (DM), this correlation has not been fully illustrated. Therefore, this study was employed to investigate the impact of DM on the correlation between aortic augmentation index and the severity of coronary artery disease.

Methods

In this study, we analyzed 197 patients who underwent coronary angiography at Anzhen Hospital from September 2015 to January 2016. Central hemodynamics were non-invasively measured with BPro® device (Health STATS, Singapore). The severity of CAD was defined according to SYNTAX scores. Type 2 diabetes was defined according to ADA guidelines. AIx@75 was defined as AIx normalized to a heart rate of 75 bpm. Receiver operating characteristics (ROC) determined the optimal cut-off value of AIx@75 to predict moderate to severe CAD. Multivariate logistic regression analysis evaluated the correlation between central hemodynamic parameters and CAD severity.

Results

Eighty-four (42.6 %) of the studied subjects were diabetic patients. Our findings were that (1) AIx@75 was significantly correlated with SYNTAX. (ROC analyzed AUC: 0.638, 95 % CI 0.555–0.721, p < 0.05). The cut-off value of AIx@75 to predict moderate-to-severe CAD as SYNTAX score more than 22 was 71.45. (2) In non-diabetic patients, correlation analysis revealed that AIx@75, augmentation pressure and peak relative time were significantly correlated with CAD severity (p < 0.05). After adjustment, AIx@75 remained as the only independent predictor of moderate-to-severe CAD (odds ratio 1.099, 95 % CI 1.028–1.176, p < 0.05). (3) In diabetic patients, the correlation between central hemodynamic parameters and the severity of CAD did not exist.

Conclusions

Aortic augmentation index was significantly related to the severity of CAD and was an independent predictor of severe CAD. However, clinical practitioners should note that its value in DM populations was compromised.

Deep breathing acutely improves arterial dysfunction in obese children: evidence of functional impairment?

BACKGROUND AND AIMS

Similarly to diabetes type 2, patients with obesity show insulin resistance and autonomic and vascular abnormalities associated with increased morbidity and mortality. We tested whether arterial dysfunction in obese children may have a functional nature, reversible with appropriate interventions (e.g., by reduction of sympathetic activity), or else results from anatomic arterial modifications (likely irreversible). For this purpose, we tested whether deep breathing (an intervention known to transiently reduce sympathetic activity) could acutely improve arterial function, hence showing a functional abnormality.

METHODS AND RESULTS

A total of 130 obese children and 67 age-matched healthy normal-weight control children were recruited. Arterial function was measured by augmentation index (AIx), by direct analysis of blood pressure contour, and by pulse wave velocity (PWV), during spontaneous and controlled breathing. The markers of metabolic syndrome were evaluated at baseline. AIx showed increased values in obese male participants as compared with the control group. Slow breathing acutely reduced Aix in obese children, to a greater extent than in normal-weight control children. Similarly, the blood pressure contour showed higher values in obese children that were significantly attenuated by slow breathing. Baseline PWV was not altered in obese participants. The markers of metabolic syndrome correlated with AIx and PWV.

CONCLUSIONS

Obese subjects showed impaired arterial function. The acute improvement in vascular abnormalities with reduction in sympathetic activity indicates that this alteration was largely functional, likely related to initial autonomic dysfunction and to metabolic abnormalities. As a consequence, this study provides a rationale for strategies aiming at preventing arterial function deterioration in the early ages.