Radial augmentation index unmasks premature coronary artery disease in younger males

Modifiable and Non-Modifiable Risk Factors for Premature Coronary Heart Disease (PCHD): Systematic Review and Meta-Analysis

AIM

We aimed to compare the prevalence of modifiable and non-modifiable coronary heart disease (CHD) risk factors among those with premature CHD and healthy individuals.

METHODS

PubMed, CINAHL, Embase, and Web of Science databases were searched (review protocol is registered in PROSPERO CRD42020173216). The quality of studies was assessed using the National Heart, Lung and Blood Institute tool for cross-sectional, cohort and case-control studies. Meta-analyses were performed using Review Manager 5.3. Effect sizes for categorical and continuous variables, odds ratio (OR) and mean differences (MD)/standardised mean differences (SMD) with 95% confidence intervals (CI) were reported.

RESULTS

A total of n=208 primary studies were included in this review. Individuals presenting with premature CHD (PCHD, age ≤65 years) had higher mean body mass index (MD 0.54 kg/m2, 95% CI 0.24, 0.83), total cholesterol (SMD 0.27, 95% CI 0.17, 0.38), triglycerides (SMD 0.50, 95% CI 0.41, 0.60) and lower high-density lipoprotein cholesterol (SMD 0.79, 95% CI: -0.91, -0.68) compared with healthy individuals. Individuals presenting with PCHD were more likely to be smokers (OR 2.88, 95% CI 2.51, 3.31), consumed excessive alcohol (OR 1.40, 95% CI 1.05, 1.86), had higher mean lipoprotein (a) levels (SMD 0.41, 95% CI 0.28, 0.54), and had a positive family history of CHD (OR 3.65, 95% CI 2.87, 4.66) compared with healthy individuals. Also, they were more likely to be obese (OR 1.59, 95% CI 1.32, 1.91), and to have had dyslipidaemia (OR 2.74, 95% CI 2.18, 3.45), hypertension (OR 2.80, 95% CI 2.28, 3.45), and type 2 diabetes mellitus (OR 2.93, 95% CI 2.50, 3.45) compared with healthy individuals.

CONCLUSION

This meta-analysis confirms current knowledge of risk factors for PCHD, and identifying these early may reduce CHD in young adults.

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.

Radial augmentation index may be an effective predictor of vascular calcification in patients on peritoneal dialysis

Vascular calcification (VC) is an important promoter of cardiovascular disease (CVD) in patients undergoing peritoneal dialysis (PD). Several indices can be used to evaluate VC, including the abdominal aortic calcification index (AACI) and carotid artery intima-media thickness (IMT); however, simpler and lesser expensive predictors, such as the radial augmentation index (RAI), should be investigated. A total of 101 patients undergoing PD were recruited to measure RAI, AACI, and carotid artery IMT and perform echocardiography. Fifty healthy controls (HCs) were recruited to undergo RAI measurement. RAI in patients undergoing PD was significantly higher than the RAI in HCs (86.25%±8.39% vs. 76.05%±9.81%, p < 0.05). Patients undergoing PD and who suffer with diabetic mellitus, hypertension, and CVD had more severe VC than those without the abovementioned diseases. In patients with PD, RAI was positively correlated with AACI (r = 0.671, p < 0.05) and carotid artery IMT (r = 0.596, p < 0.05). RAI was positively correlated with left ventricular end-diastolic dimensions (LVDd; r = 0.678, p < 0.05), left ventricular mass index (r = 0.595, p < 0.05), and negatively correlated with early-diastolic mitral inflow velocity/late-diastolic mitral inflow velocity (r = -0.342, p < 0.05) and left ventricular ejection fraction (r= -0.497, p < 0.05). Multiple linear regression analysis showed that RAI was associated with AACI, LVDd, age, and serum phosphate (p < 0.05). RAI might be an effective predictor of VC and cardiac structural/functional abnormalities in patients undergoing PD.

Development of an Efficient, Non-Invasive Method for Cardiovascular Disease Risk Stratification in a Resource-Limited Setting

BACKGROUND

Augmentation Index (AIx) is considered as an important predictor of cardiovascular disease. So, quantification of AIx may provide a rapid cost-effective and non-invasive means of cardiovascular risk stratification. At present, WHO/ISH risk prediction charts are used to predict 10-year risk of a fatal or nonfatal major cardiovascular event, an assessment which requires laboratory support for blood chemistry and thus making it ill-suited for resource-limited settings.

OBJECTIVES

In this study, we examined the association of AIx with cardiovascular risk as determined by the WHO/ISH chart and identified AIx cut-offs to stratify patients into different risk categories.

METHODS

A case-control study with 162 cases and 61 controls was conducted in a tertiary care hospital in eastern India. Data were obtained for demographic, anthropometric, cardiovascular, and biochemical parameters. Cardiovascular risk assessment was carried out by WHO/ISH risk model in R. Statistical analysis was done for examining the association of AIx with WHO/ISH cardiovascular risk and for identifying AIx cut-offs to stratify patients into different risk categories.

RESULTS

Box and whisker plots for assessing the correlation between AIx and WHO/ISH cardiovascular risk showed an increase in the median value of AIx with increasing risk in both cases and controls. Heart rate corrected AIx showed a steady increase with increasing risk in males. AIx cutoffs showed good sensitivity and specificity for each risk category.

CONCLUSION

AIx is remarkably associated with cardiovascular risk as assessed by the WHO/ISH chart and the AIx cut-offs obtained in the study can be used as an efficient, non-invasive surrogate biomarker of cardiovascular risk even in resource-limited settings.

Noninvasive validation of central and peripheral augmentation index estimated by a novel wrist-worn tonometer

BACKGROUND

The validation of new blood pressure devices with easier use and more rapid data collection may facilitate the incorporation of these measures into clinical practice. We analyze the reliability and validity of Pulse Wave Analysis as reported by a novel wrist-worn device, easy and quick to use, comparing central and peripheral augmentation index (AIx) with the same measures from the SphygmoCor. Additionally, we analyzed clinical relevance through the association of the Pulse Wave Analysis, as reported by a novel wrist-worn device, with other cardiovascular parameters.

METHODS

Cross-sectional study including 254 participants. Mean age was 51.9 ± 13.4 years and 53% were women.

MEASUREMENTS

peripheral AIx (PAIx) and central AIx (CAIx) by the wrist-worn device and SphygmoCor (MM3); carotid-femoral (cf) pulse wave velocity (PWV) by SphygmoCor (MM3); cardioankle-vascular index (CAVI), ankle-brachial index (ABI) and brachial-ankle (ba) PWV by the Vasera device and carotid-intima media thickness (IMT) by ultrasonography.

RESULTS

Intra-observer intra-class correlation coefficient (ICC) for PAIx was 0.886 (95% CI 0.803-0.934) and for CAIx 0.943 (95% CI 0.901-0.968) with Bland Altman limits of agreement -0.75 (-23.8 to 21.8) and 0.08 (-15.7 to 15.9), respectively. Inter-observer ICC for PAIx was 0.952 (95% CI 0.915-0.972) and CAIx 0.893 (95% CI 0.811-0.939) with limits of agreement -0.45 (-13.7 to 12.8) and 0.43 (-17.7 to 18.5), respectively. Comparing the wrist-worn device with SphygmoCor, the ICC was 0.849 (95% CI 0.798-0.887) for PAIx, and 0.783 (95% CI 0.711-0.838) for CAIx. In Bland-Altman, limits of agreement for PAIx 1.03 (-20.67 to 22.73), and for CAIx -2.14 (-24.79 to 20.50). PAIx and CAIx, from the wrist-worn device, correlated with age, CAVI, ABI, baPWV, cfPWV, IMT, glomerular filtration and cardiovascular risk.

CONCLUSION

AIx measurements by wrist-worn device shows a good intra-observer and inter-observer reliability, inter-device noninvasive reliability and validity when compared with SphygmoCor, and clinical relevance by association with measures of vascular structure and function, end-organ damage and cardiovascular risk.

TRIAL REGISTRATION

Clinicaltrials.gov NCT02623894; https://clinicaltrials.gov/ct2/show/NCT02623894.

Vascular Function and Serum Lipids in Women with Spontaneous Preterm Delivery and Term Controls

Background: Spontaneous preterm delivery (sPTD) is associated with a twofold increased risk of future maternal cardiovascular disease. We hypothesized that women with sPTD would demonstrate greater vascular dysfunction postpartum compared to women with term delivery. Materials and Methods: In a case-controlled, matched pilot study, we enrolled 20 women with sPTD (gestation ≤34 weeks), and 20 term control women (gestation ≥39 weeks) were matched for age (±5 years), parity, ethnicity, and route of delivery. Vascular function, serum lipids, C-reactive protein, and interleukin-6 were completed within 24-72 hours postpartum. Statistical analysis included paired t-tests based on match and mixed effects linear regression models and adjusted for potential confounders. Results: The mean age for sPTD and term controls was 33 ± 6 years and 32 ± 6 years, respectively. Women with sPTD had significantly lower augmentation index-75 (24.1% ± 16.1% vs. 39.9% ± 15.2%, p = 0.001) and central pulse pressure (29.1 ± 5.4 mmHg vs. 34.6 ± 4.7 mmHg, p = 0.004), but no difference in pulse wave velocity (5.1 ± 1.6 m/s vs. 5.6 ± 1.5 m/s, p = 0.12) compared to controls. Women with sPTD had significantly lower high-density lipoprotein cholesterol (59.4 ± 12.5 mg/dL vs. 67.6 ± 13.1 mg/dL, p = 0.035) compared to controls. Analysis of chorioamnionitis and magnesium sulfate did not alter the results. Conclusions: Women with sPTD have signs of lower smooth muscle tone in the early postpartum period compared to women with term delivery. Further research is required to understand mechanistic pathways in sPTD and future maternal cardiovascular disease risk.

Diastolic Augmentation Index Improves Radial Augmentation Index in Assessing Arterial Stiffness

Arterial stiffness is an important risk factor for cardiovascular events. Radial augmentation index (AI_r) can be more conveniently measured compared with carotid-femoral pulse wave velocity (cfPWV). However, the performance of AI_r in assessing arterial stiffness is limited. This study proposes a novel index AI_rd, a combination of AI_r and diastolic augmentation index (AI_d) with a weight α, to achieve better performance over AI_r in assessing arterial stiffness. 120 subjects (43 ± 21 years old) were enrolled. The best-fit α is determined by the best correlation coefficient between AI_rd and cfPWV. The performance of the method was tested using the 12-fold cross validation method. AI_rd (r = 0.68, P < 0.001) shows a stronger correlation with cfPWV and a narrower prediction interval than AI_r (r = 0.61, P < 0.001), AI_d (r = −0.17, P = 0.06), the central augmentation index (AI_c) (r = 0.61, P < 0.001) or AI_c normalized for heart rate of 75 bpm (r = 0.65, P < 0.001). Compared with AI_r (age, P < 0.001; gender, P < 0.001; heart rate, P < 0.001; diastolic blood pressure, P < 0.001; weight, P = 0.001), AI_rd has fewer confounding factors (age, P < 0.001; gender, P < 0.001). In conclusion, AI_rd derives performance improvement in assessing arterial stiffness, with a stronger correlation with cfPWV and fewer confounding factors.

Preeclampsia and Vascular Function: A Window to Future Cardiovascular Disease Risk

Preeclampsia affects ∼3%-7% of all pregnancies and is the third leading cause of maternal mortality globally. Growing evidence indicates that preeclampsia results from vascular dysfunction, which also increases the risk for future cardiovascular events. Until recently, preeclampsia was considered a disorder limited to pregnancy, which fully resolved with the delivery of the placenta; however, it is now clear that women with a history of preeclampsia have approximately double the risk of future cardiovascular events compared to women with normotensive pregnancies. The aims of this review were to describe the hemodynamic and vascular changes that occur in normal and preeclamptic pregnancies, to review noninvasive methods to test vascular function, and to discuss the associated increased cardiovascular disease risk related to preeclampsia.

Increased pulse wave velocity and augmentation index after isometric handgrip exercise in patients with coronary artery disease

BACKGROUND

Arterial stiffness of patients with coronary artery disease (CAD), which is expected to be increased due to a generalized atherosclerotic process of human body, may be more evident after the acute increase of blood pressure (BP) or peripheral vascular resistance. Isometric handgrip exercise is a simple and easily applicable method to achieve this goal. We investigated the changes of hemodynamic parameters and arterial stiffness indexes after handgrip exercise in patients with CAD.

METHODS

Forty-two subjects, who underwent coronary angiography (CAG), were enrolled. After CAG, baseline arterial waveforms were traced at the aortic root and external iliac artery using right coronary catheters. Arterial waveforms were recorded at 1, 2, and 3 min in the aortic root and at 3 min in the external iliac artery after isometric handgrip exercise at 30% ~ 40% of the maximal handgrip power. Augmentation pressure (AP) and augmentation index (AIx) were measured at aortic pressure waveforms. Pulse wave velocity (PWV) was calculated using the ECG-gated time difference of the upstroke of arterial waveforms and the distance between the aortic root and the external iliac artery.

RESULTS

Thirty patients had CAD (CAD group), and others showed no significant coronary stenosis (non-CAD group). Baseline hemodynamic parameters including AIx and PWV were not different between both groups. After isometric handgrip exercise, central systolic blood pressure (BP), central diastolic BP, central pulse pressure, peripheral systolic BP, and peripheral pulse pressure were increased in all patients. AIx inclined significantly from 1 min after exercise only in patients with CAD (before 17.7% ± 9.7% vs. 3 min after exercise 22.3% ± 10.7%, p < 0.001). PWV also increased significantly after exercise only in patients with CAD (before 10.03 ± 1.99 m/s vs. 3 min after 11.09 ± 2.45 m/s, p < 0.001).

CONCLUSIONS

Arterial stiffness indexes at rest were not different between patients with and without CAD. After isometric handgrip exercise, increased arterial stiffness became evident only in patients with CAD.

A new tonometric device for radial augmentation index and subendocardial viability ratio: potential use in health screening

Augmentation index (AIx) and subendocardial viability ratio (SEVR) are widely accepted indices of wave reflection and myocardial oxygen demand relative to supply. This study aimed to validate a new tonometric device (IIM-2010A) for obtaining AIx and SEVR from radial artery. A total of 68 outpatients (32 men and 36 women) aged 20 to 76 years (44.7±16.6 years) recruited from a health screening center participated in the study. AIx was obtained from radial pressure using the HEM-9000AI and IIM-2010A devices, while SEVR was measured from carotid pressure with the tonometric method and from radial pressure by the IIM-2010A device. In a subgroup of 24 patients, the measurements of AIx and SEVR were repeated after an interval of 10 minutes. The correlation of radial AIx between the IIM-2010A and HEM-9000AI devices was highly significant (r=0.956, P<.01). Radial SEVR determined from IIM-2010A was also highly related to carotid SEVR (r=0.864, P<.01), although the value was about 13.1% lower. There was no statistically significant difference between the repeated measurements of both indices. The lower coefficient of variation (2.9% vs 4.3% for AIx, 3.3% vs 4.1% for SEVR) and higher intraclass correlation coefficient (0.96 vs 0.91 for AIx, 0.93 vs 0.86 for SEVR) of IIM-2010A confirmed better short-term reproducibility, compared with the HEM-9000AI device and carotid tonometry. The new tonometric device IIM-2010A is effective and reproducible in calculating radial AIx and SEVR and has potential use in health screening.

Ivabradine therapy to unmask heart rate-independent effects of β-blockers on pulse wave reflections

BACKGROUND

Prior studies suggest that β-blockers lead to increased pulse wave reflections, thereby negating the blood pressure lowering effects on cardiovascular mortality. Parts of these effects may be induced by the heart rate reduction under β-blockade. The aim of this study was to unmask heart rate-independent effects of β-blockade on pulse wave reflections by switching therapy from β-blockers to ivabradine, an I f channel inhibitor without impact on systemic hemodynamics.

METHODS

14 male patients (age 61 ± 3 years, LVEF 62 ± 1 %) with arterial hypertension and coronary artery disease (CAD) under chronic β-blocker therapy at moderate dosage and additional renin-angiotensin system-blocking therapy were included. We determined radial augmentation index (rAI) by radial applanation tonometry in patients under β-blockade both at rest and during early recovery after exercise. β-Blockers were then replaced by ivabradine. Six weeks later, patients were re-tested at rest and after exercise under ivabradine therapy.

RESULTS

Mean heart rate (68 ± 3 vs. 63 ± 3 bpm; p = ns) and resting mean arterial pressure (98 ± 2 vs. 98 ± 2 mmHg; p = ns) were not different between β-blocker or ivabradine therapy, respectively. The rAI remained unchanged after switching therapy from β-blocker to ivabradine (86 ± 2 vs. 84 ± 4 %; p = ns). Post exercise, the rAI revealed an identical decrease in both groups (-7.2 ± 2.4 vs. -5.4 ± 2.5 %, p = ns). The increase in heart rate between resting conditions and early recovery post exercise was inversely correlated with the decrease of rAI under β-blockade (r = -0.70; p < 0.01) and showed a trend towards correlation under ivabradine (r = -0.52; p = 0.07).

CONCLUSION

In men at the age of 60 years and CAD, β-blockade does not exert heart rate-independent, pleiotropic effects on peripheral pulse wave reflections, both at rest or after exercise. Our results fit well within recent studies, demonstrating the fundamental influence of heart rate on rAI.

Physical activity is independently associated with multiple measures of arterial stiffness in adolescents and young adults

Physical activity (PA) is associated with decreased levels of arterial stiffness in adults, but the relationship between PA and multiple measures of arterial stiffness in adolescents and young adults is not clear. The objective of this study was to test the hypothesis that PA is an independent predictor of multiple measures of arterial stiffness in adolescents and young adults. A total of 548 participants were enrolled in a study of the cardiovascular effects of obesity and type 2 diabetes mellitus (T2DM) (lean, 201; obese, 191; T2DM, 156). Anthropometrics, blood pressure, central and peripheral measures of arterial stiffness (pulse wave velocity, brachial distensibility, and augmentation index), blood (lipids and metabolic tests), and accelerometry data were collected. General linear modeling was performed to test for the independent relationship of PA on arterial stiffness. The mean age of the participants was 17.9 years (standard deviation, 3.5 years). After adjusting for other cardiovascular disease risk factors such as age, sex, body size, mean arterial pressure, and the presence of obesity or T2DM, PA was an independent predictor of augmentation index and brachial distensibility (P < .001). A greater effect of PA on pulse wave velocity was found in participants with T2DM (P = .009) compared with participants in the lean or obese groups. Physical activity is significantly and independently associated with multiple measures of arterial stiffness in adolescents and young adults. The role of PA in the prevention of cardiovascular disease target organ damage in youth, independent of energy balance, merits further exploration.

RADIAL DIASTOLIC AUGMENTATION INDEX IS A USEFUL PREDICTOR OF ARTERIAL STIFFNESS

Diastolic augmentation index (DAI), calculated from radial artery pressure waveform, has been associated with the risk of cardiovascular disease. In the present study, we aimed to evaluate whether DAI could be used as a predictor of arterial stiffness and the effect of heart rate (HR) on it. Measurements of anthropometric parameters, blood pressure (BP), Augmentation index (AI) and DAI were taken in 242 healthy subjects (130 men and 112 women; age 16–78 years). DAI and AI were measured in a subgroup of 16 subjects (10 men and 6 women; age 19–69 years) in a two-month follow-up study, which aimed to investigate the effect of HR changes. Statistically, DAI was higher in women compared to men (44.8% ± 7.7% compared with 43.6% ± 6.9%, P < 0.05). DAI was decreased with age (men: r = -0.755, P < 0.05; women: r = -0.708, P < 0.05) and negatively correlated to AI (men: r = -0.704, P < 0.05; women: r = -0.756, P < 0.05). There was no significant change in DAI when HR ranged from 60 to 80 bpm. Multiple regression analysis demonstrated fewer determinants affect DAI compared with AI. These findings indicate that the simple radial DAI might be used as an index to assess vascular aging.