Large artery stiffness predicts ischemic threshold in patients with coronary artery disease

Arterial stiffness as a risk factor for coronary atherosclerosis

The major pathophysiologic process of coronary atherosclerosis is a defect or injury of the arterial endothelial function. The rate of progression of coronary atherosclerosis is highly variable and mainly determined by risk contributors such as lipids, glucose, and smoking. Coronary plaque rupture is the precipitating factor for clot formation and acute coronary events. Measurement of arterial stiffness with different noninvasive techniques provides information about the functional and structural vascular changes at the level of the aorta, muscular conduit arteries, the peripheral branches, and the microvascular components. Arterial stiffness has been related to the Framingham and other cardiovascular risk scores. Large artery stiffness contributes to exercise-induced myocardial ischemia in patients with coronary artery disease. It can predict the outcome after coronary interventions. There is now evidence that arterial stiffness is a predictor for cardiovascular events in the general population, in patients with hypertension, end-stage renal disease, impaired glucose intolerance, and coronary artery disease. Future studies are warranted to demonstrate the value of follow-up of arterial stiffness as a marker of reduction of arterial wall damage during antihypertensive, antidiabetic, and lipid-lowering therapy. Promising study results show that measurement of arterial stiffness could become an important part of the routine assessment of patients in daily practice.

Presence of abdominal aortic calcification is significantly associated with all-cause and cardiovascular mortality in maintenance hemodialysis patients

BACKGROUND

Although abdominal aortic calcification (AAC) is reported as a predictor for cardiovascular mortality in the general population, it is unknown whether this is also true in hemodialysis patients in whom vascular calcification and cardiovascular diseases are highly prevalent.

STUDY DESIGN

Cohort study.

SETTINGS & PARTICIPANTS

515 patients on maintenance hemodialysis therapy at a single center.

PREDICTOR

AAC evaluated in a plain roentgenograph of the lateral abdomen at baseline.

OUTCOMES & MEASUREMENTS

All-cause and cardiovascular death.

RESULTS

Mean age was 60 +/- 12 (SD) years. AAC was present in 291 patients (56.5%). During a mean follow-up period of 51 +/- 17 months, there were 103 all-cause deaths, of which 41 were from cardiovascular diseases. Of patients with and without AAC, 27.8% and 9.8% died, respectively (11.6% and 3.1% of cardiovascular diseases, respectively). Kaplan-Meier analysis showed that all-cause mortality was significantly greater in patients with AAC compared to those without (P < 0.0001, log-rank test). Similarly, cardiovascular mortality was significantly greater in the former than in the latter group (P = 0.0001, log-rank test). Multivariate Cox proportional hazards analysis found that the presence of AAC was significantly associated with increased all-cause mortality (hazard ratio, 2.07; 95% confidence interval, 1.21 to 3.56; P < 0.01) and increased cardiovascular mortality (hazard ratio, 2.39; 95% confidence interval, 1.01 to 5.66; P < 0.05) after adjustment for age, hemodialysis duration, presence of diabetes, serum albumin level, and C-reactive protein level.

LIMITATIONS

Nonquantitative assessment of AAC and the lack of information for medication and history of cardiovascular diseases.

CONCLUSION

The presence of AAC is significantly associated with both all-cause and cardiovascular mortality in hemodialysis patients, suggesting that careful attention should be given to the presence of AAC in a simple radiograph of the lateral abdomen as a prognostic indicator.

Evidence suggests rigid aortic grafts increase systolic blood pressure: results of a preliminary study

Abdominal aortic aneurysm (AAA) is a serious complication of the aorta and is treated using vascular bypass grafts. Two main classes of graft are available to treat AAA; grafts implanted by open surgery and stent-grafts implanted using minimally invasive endovascular techniques. Both classes of graft consist of an aortic section which bifurcates into two iliac sections. It has been hypothesized that implantation of aortic grafts and stent-grafts serve to significantly increase abdominal aortic pressures. In this study, an open-loop computer-controlled pumping system was built to produce physiologically realistic pressure and flow-rates. Models of a compliant abdominal aortic aneurysm, a compliant walled graft and a tapered graft were manufactured using an injection moulding technique and fused deposition modelling was used to create a rigid walled graft. A specific transient flow-rate waveform was then applied at the inlet of each model and the resulting pressure waveforms 30 mm upstream from the bifurcation was recorded. Peak pressure measurements were recorded over the course of the pulse for each model. The compliant aneurysm model was found to have a systolic pressure of 107 mmHg while the complaint graft model was 153 mmHg. The rigid graft model had a peak systolic pressure of 199 mmHg. In the tapered graft, the peak pressure dropped to 142 mmHg. The data suggests that implanting a graft model in place of an aneurysm model in an in vitro flow circuit can increase the pressures recorded upstream from the iliac bifurcation and that tapered grafts may alleviate this problem.

Effect of dietary supplementation with βcasein A1 or A2 on markers of disease development in individuals at high risk of cardiovascular disease

The present study is the first to examine the hypothesis that dietary supplementation with β-casein A1 promotes an increased risk relative to supplementation with β-casein A2 in patients traditionally at high risk of developing CVD. The study was conducted in fifteen asymptomatic participants (six male; nine female) at high risk of developing CVD. A double-blind cross-over study design was used with a total duration of 24 weeks. Dietary intervention was a daily supplementation (25g) of either casein A1 or A2 (for 12 weeks each). Surrogate measures of cardioprotection studied included the examination of vascular (endothelium and arterial) function, resting blood pressure, plasma lipids and biochemical markers of inflammation. Total plasma cholesterol levels were significantly lower following 12 weeks of both casein A1 and A2 interventions but the decrease was not different between intervention. Plasma insulin, homocysteine, C-reactive protein, fibrinogen, protein C and S and von Willebrand factor levels were not different between the two casein supplements. Endothelium function, measured as a vascular response using venous occlusion plethysmography to intra-aterial infusions of the endothelium-dependent agonist acetylcholine, were not different between the two casein interventions. Similarly, neither blood pressure nor measures of large artery stiffness were affected by differing the casein variant. We therefore conclude that there is no evidence from the present study that supplementation with casein A1 has any cardiovascular health disadvantage over consumption of casein A2.

Relationship between arterial distensibility and coronary atherosclerosis in angina patients

OBJECTIVE

Arterial stiffening is associated with an increased risk of cardiovascular disease. However, limited evidence exists on whether it also relates to subclinical atherosclerosis, thereby providing a non-invasive marker of the overall cardiovascular status. The aim of the present study was to provide information on arterial stiffening in angina patients in whom angiographic evaluation allowed quantification of coronary atherosclerosis.

METHODS

We studied 101 patients with angina from a large number admitted to our hospital for coronary angiography. In each patient, radial (RA), subdiaphragmatic aorta (AO) and carotid (CA) distensibility (Dist) were measured by an ultrasonic device, following ultrasonic exclusion of atherosclerotic lesions at these specific sites. Patients were classified into three groups according to the angiographic findings: (i) no significant coronary lesions (lumen obstruction < 50%, group A); (ii) one (group B); and (iii) two or three (group C) coronary vessels with hemodynamic significant plaques (lumen obstruction > 50%).

RESULTS

Age, male prevalence, previous cardiovascular disease and interventions were progressively greater or more common from group A to C, whereas several other risk factors (plasma glucose, serum cholesterol, smoking, history of hypertension, etc.) did not differ between the three groups or between the group with single vessel (B) versus the group with multivessel disease (C). CA and AO Dist decreased progressively from group A to C with a significant relationship in the group as a whole between distensibility values and the number of diseased vessels. The progressive decrease in AO Dist from group A to C remained significant after adjustment for variables that showed between-group differences (such as gender, age and systolic blood pressure) and the ROC curve showed it to be a more sensitive and specific marker of coronary atherosclerosis than CA Dist. RA Dist was similar in the three groups and showed no relationship with the number of diseased vessels in the group as a whole.

CONCLUSION

In patients with angina, AO and CA Dist are related to the severity of coronary atherosclerosis, with the relationship being better for alterations in aortic than in carotid mechanical properties. Large elastic artery (and in particular aortic) stiffening can thus be considered as a marker of the severity of coronary atherosclerosis, providing non-invasive obtainable information on the need to proceed with further clinical examinations.

A new technique for assessing arterial pressure wave forms and central pressure with tissue Doppler

Background

Non-invasive assessment of arterial pressure wave forms using applanation tonometry of the radial or carotid arteries can be technically challenging and has not found wide clinical application. 2D imaging of the common carotid arteries is routinely used and we sought to determine whether arterial waveform measurements could be derived from tissue Doppler imaging (TDI) of the carotid artery.

Methods

We studied 91 subjects (52 men, age 52 ± 14 years) with and without cardiovascular disease. Tonometry was performed on the carotid artery simultaneously with pulsed wave Doppler of the LVOT and acquired digitally. Longitudinal 2D images of the common carotid artery with and without TDI were also acquired digitally and both TDI and tonometry were calibrated using mean and diastolic cuff pressure and analysed off line.

Results

Correlation between central pressure by TDI and tonometry was excellent for maximum pressure (r = 0.97, p < 0.0001). The mean differences between central pressures derived by TDI and tonometry were minimal (systolic 5.36 ± 5.5 mmHg; diastolic 1.2 ± 1.2 mmHg).

Conclusion

Imaging of the common carotid artery motion with tissue Doppler may permit acquisition of a waveform analogous to that from tonometry. This method may simplify estimation of central arterial pressure and calculation of total arterial compliance.

The Clinical Application of Metabolic Therapy for Cardiovascular Disease

Metabolic therapy involves the administration of a substance normally found in the body to enhance a metabolic reaction within the cell. This may be achieved in two ways. Firstly, for some systems a substance can be given to achieve greater than normal levels in the body so as to drive an enzymic reaction in a preferred direction. Secondly, metabolic therapy may be used to correct an absolute or relative deficiency of a cellular component. Thus, metabolic therapy differs greatly from most standard cardiovascular pharmacologic therapies such as the use of ACE Inhibitors, beta-blockers, statins and calcium channel antagonists that are given to block rather than enhance cellular processes.

Relationship between impaired elastic properties of aorta with left ventricle geometric patterns and left ventricle diastolic functions in patients with newly diagnosed essential hypertension

The aim of this study was to investigate the association between elastic properties of aorta with left ventricle (LV) geometric patterns and LV diastolic functions in patients with newly diagnosed hypertension (HT). We studied 149 patients with newly diagnosed HT and 29 healthy control subjects. Echocardiographic examination was performed to all subjects. Ascending aorta (Ao) diameters (mm/m2) and Ao elastic indexes - namely, Ao strain [AS] (%), Ao distensibility [AD] (cm2 dyn(-1) x 10(-6)) were calculated. Four different geometric patterns were identified in hypertensive patients according to LV mass index (LVMI) and relative wall thickness (RWT). Tissue Doppler-derived Ea/Aa was determined from the all subjects. Patients vs. control subjects had lower mean AS and AD (p < 0.001 for both). Mean AS and AD of all geometric patterns significantly decreased compared with control group (p < 0.05 for all). Both AS and aortic AD of concentric remodelling (CR; p = 0.017 for both) and concentric hypertophic groups (p < 0.001 for both) were decreased compared with normal LV group. AS and AD of concentric hypertrophic pattern was lower than that of the CR group (p = 0.011 and 0.020 respectively) and the eccentric hypertrophic group (p < 0.001 and p = 0.002, respectively). Both AS and AD of the CR group were similar to that of the eccentric hypertrophic group (p > 0.05 for both). Both AS and AD were significantly correlated with age (beta = -0.178, p = 0.025, beta = -0.158, p = 0.029 respectively), LVMI (beta = -0.223, p = 0.022, beta = -263, p = 0.003 respectively), RWT (beta = -0.196, p = 0.019, beta = -0.189, p = 0.013 respectively) and Ea/Aa (beta = 0.174, p = 0.045, beta = 0.247, p = 0.002 respectively) in multiple linear regression analysis. Elastic properties of aorta were impaired in newly diagnosed HT. The degree of this impairment is different among various LV geometric patterns. In addition, impaired elastic properties of aorta were associated with RWT, LVMI and diastolic disfunctions, besides age, but not with LV geometry.

Pulse wave velocity is increased in patients with transient myocardial ischemia

OBJECTIVE

We have recently shown that mean pulse pressure is higher in patients with transient myocardial ischemia. Pulse pressure elevation might be an important consequence of increased arterial stiffness. The aim of this study was to prove if arterial stiffness is changed in patients with transient myocardial ischemia who bear a high cardiovascular risk. Additionally we investigated whether arterial stiffness or wave reflection is the best indicator for transient myocardial ischemia. Aortic pulse wave velocity (PWV) is a measure of arterial stiffness, and augmentation index (AIx) an indication of arterial wave reflection. Both are indicators for cardiovascular risk.

METHODS

PWV (carotid-femoral) and AIx (SphygmoCor) were assessed in 74 hypertensive patients. Transient myocardial ischemia was detected using an ST-triggered 24-h ambulatory blood pressure monitoring device.

RESULTS

ST-segment depressions were recorded in 30 of 74 patients. There were no significant differences with regard to age, mean arterial pressure, systolic blood pressure, diastolic blood pressure or heart rate. PWV was seen to be higher in patients with transient myocardial ischemia (10.6 versus 9.5 m/s, P = 0.036). There was no significant difference in AIx between the two groups. PWV (r = 0.36, P = 0.002) but not AIx correlated with pulse pressure.

CONCLUSIONS

PWV is higher in hypertensive individuals (age > 60 years) with transient myocardial ischemia, suggesting that PWV is an indicator of increased cardiovascular risk. Although AIx is known to be associated with several cardiovascular diseases, it was not seen to be associated with silent myocardial ischemia. Our results suggest that the clinical significance of parameters of arterial stiffness and arterial wave reflection change with age, with a higher clinical importance of PWV indicated in patients over the age of 60.

Regional arterial stiffness associated with ischemic heart disease in type 2 diabetes mellitus

Arterial stiffness is increased in type 2 diabetes mellitus, and diabetes preferentially affects arterial stiffness of the central (elastic, capacitive) over peripheral (muscular, conduit) arteries. We hypothesized that arterial stiffness of the central artery may be more closely associated with ischemic heart disease (IHD) than stiffness of peripheral arteries in type 2 diabetes mellitus. The subjects were 595 type 2 diabetes patients including 70 with IHD. Arterial stiffness was measured as pulse wave velocity (PWV) in the heart-carotid, heart-femoral, heart-brachial, and femoral-ankle regions. The PWV values of the four segments correlated with each other in patients without IHD. However, the correlations were less impressive in those with IHD, suggesting unequal stiffening of regional arteries in IHD. As compared with patients without IHD, the IHD group showed significantly higher PWV values of the four arterial segments, particularly of the heart-femoral region. The presence of IHD was significantly associated with higher heart-femoral PWV, and this association remained significant and independent of other factors in a multiple logistic regression analysis. Pulse pressure was more strongly correlated with PWV of the heart-femoral than other arterial regions. Thus, diabetic patients with IHD have increased stiffness of arteries, particularly of the aorta, supporting the concept that central arterial stiffness plays an important role in the development of IHD.

Aortic Stiffness Is an Independent Determinant of B-Type Natriuretic Peptide in Patients with Coronary Artery Disease

Previous studies demonstrated that the B-type natriuretic peptide (BNP) level is high in some patients with coronary artery disease (CAD) despite a preserved left ventricular function, although the mechanism underlying this increase in patients with CAD has not been fully elucidated. Because aortic stiffness is greater in patients with CAD and increases with CAD severity, there is a possibility that an increased aortic stiffness in turn increases the elevation of the BNP level in patients with CAD. In this study, we measured BNP level and brachial-ankle pulse wave velocity (baPWV) in 134 patients with CAD, and evaluated the relationship between BNP and baPWV. The patients were classified on the basis of the quartiles of BNP level to identify the characteristics of patients with a high BNP level. baPWV was significantly greater in patients classified into the highest quartile of BNP level than in those classified into the other quartiles. Multivariate analysis demonstrated that baPWV and left ventricular ejection fraction independently correlated with BNP level. Logistic regression analysis demonstrated that the odds ratio for the highest quartile of BNP level increased with baPWV quartile. This association remained significant after adjustment for systolic and diastolic function. In conclusion, increased aortic stiffness possibly underlies the increase in the BNP level in patients with CAD.

The aortic distensibility alteration is an index of influence of ischemic preconditioning to myocardial performance

BACKGROUND

Ischemic preconditioning (IP) is a cardioprotective phenomenon, induced by brief episodes of myocardial ischemia, which is supposed to affect not only the myocardium, but also the entire cardiovascular system. Considering that patients with coronary artery disease (CAD) have also been described to present impaired aortic mechanical properties, we tried to investigate the possible influence of the late phase of IP on aortic distensibility in patients with CAD.

METHODS

Fifty patients, aged 48 to 72 (mean, 57+/-6 years), with angiographically confirmed CAD and exercise-induced myocardial ischemia, underwent two treadmill exercise testings (ETs). The second ETs was performed the next day. Thallium-201 scintigraphy was performed during the first and the second ET. Aortic distensibility was evaluated before each exercise testing by a non-invasive technique, using two-dimensional guided M-mode transthoracic echocardiography and arterial pressure was measured simultaneously at the brachial artery by sphygmomanometry.

RESULTS

The patients were divided in 2 groups according to the extent of myocardial ischemia at peak exercise of the second test, compared to the first test. In 35 (70%) of the studied patients ischemia signs were reduced during the second ET (Group A), while in the rest 15 (30%) of the patients (Group B) no improvement or even worsening of the observed ischemia signs was demonstrated by the studied exercise parameters and the extent of myocardial ischemia in thallium-scintigraphy. Increased aortic distensibility during the second measurement was found in 33 (94%) of the 35 patients of Group A but only in 1 (7%) of the 15 patients of Group B. Aortic distensibility was found to be significantly improved in patients of Group A, while it was found to be worsened in Group B patients.

CONCLUSIONS

The aortic distensibility alteration could be used as an index of influence of ischemic preconditioning to exercise-induced myocardial ischemia, which could be considered indicative of the systemic effects of IP in humans.

Pre-operative Preparation for Cardiac Surgery Utilising a Combination of Metabolic, Physical and Mental Therapy

Cardiac surgery represents major metabolic, physical and mental stresses associated with an increased production of reactive oxygen species. These stresses may hamper post-operative recovery, increasing hospitalisation times and operative mortality. We conducted a quality assurance and feasibility study to evaluate and monitor the safety and efficacy of a new program of combined pre-operative metabolic (enhanced antioxidant), physical and mental therapy to counter these stresses prior to cardiac surgery.

METHODS

Sixteen cardiac surgery patients received metabolic therapy consisting of the antioxidants coenzyme Q(10) (CoQ(10)) (300 mg) and alpha-lipoic acid (300 mg), combined with magnesium orotate (1200 mg), and omega-3 fatty acids (3g) given daily for a mean 36+/-7 days up until the day of operation. Patients also received a regimen of physical therapy incorporating non-exhaustive, light exercise and stretching techniques. Mental therapy in the form of stress reduction, relaxation and music was also provided. Blood levels of CoQ(10) and malondialdehyde (MDA) were measured and a quality of life (QoL) questionnaire (SF-36) was administered before, after the program and 1 month after surgery. A patient satisfaction survey was conducted at six weeks post-operatively.

RESULTS

During the pre-operative period, treated patients (n=16) showed significant improvements in QoL composite scores, physical (33.5+/-4.1 to 41.0+/-4.5, p=0.005) and mental (44.3+/-4.5 to 54.1+/-5.3, p=0.006). CoQ(10) levels increased from 725.6+/-96.1 nmol/l to 3019.9+/-546.4 nmol/l (p=0.006), MDA levels decreased from 2.2+/-0.9 microM to 1.4+/-0.7 microM (p=0.013) and systolic blood pressure decreased from 140+/-4.0 mmHg to 132+/-3.0 mmHg (p=0.002). One month after surgery the treated group (n=14) demonstrated significant improvements from pre-operative baseline in QoL composite scores, physical (38.9+/-4.0 to 57.9+/-5.4, p=0.01) and mental (50.3+/-5.6 to 69.3+/-4.8, p=0.03) compared to a previously reported similar group of cardiac surgery patients (n=74) whose physical and mental scores decreased from 43.0 to 42.8 (p=0.05) and 53.8 to 49.8, respectively (p=0.05).

CONCLUSION

These preliminary results suggest that a program of combined metabolic, physical and mental preparation before cardiac surgery is safe, feasible and may improve quality of life, lower systolic blood pressure, reduce levels of oxidative stress and thus has the potential to enhance post-operative recovery.

Acute effects of cold exposure on central aortic wave reflection

The purpose of this study was to determine the effects of acute cold exposure on the timing and amplitude of central aortic wave reflection and central pressure. We hypothesized that cold exposure would result in an early return of reflected pressure waves from the periphery and an increase in central aortic systolic pressure as a result of cold-induced vasoconstriction. Twelve apparently healthy men (age 27.8 ± 2.0 yr) were studied at random, in either temperate (24°C) or cold (4°C) conditions. Measurements of brachial artery blood pressure and the synthesis of a central aortic pressure waveform (by noninvasive radial artery applanation tonometry and use of a generalized transfer) were conducted at baseline and after 30 min in each condition. Central aortic augmentation index (AI), an index of wave reflection, was calculated from the aortic pressure waveform. Cold induced an increase ( P < 0.05) in AI from 3.4 ± 1.9 to 19.4 ± 1.8%. Cold increased ( P < 0.05) both brachial and central systolic pressure; however, the magnitude of change in central systolic pressure was greater ( P < 0.05) than brachial (13 vs. 2.5%). These results demonstrate that cold exposure and the resulting peripheral vasoconstriction increase wave reflection and central systolic pressure. Additionally, alterations in central pressure during cold exposure were not evident from measures of brachial blood pressure.

Differential impact of blood pressure-lowering drugs on central aortic pressure and clinical outcomes: principal results of the Conduit Artery Function Evaluation (CAFE) study

BACKGROUND

Different blood pressure (BP)-lowering drugs could have different effects on central aortic pressures and thus cardiovascular outcome despite similar effects on brachial BP. The Conduit Artery Function Evaluation (CAFE) study, a substudy of the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT), examined the impact of 2 different BP lowering-regimens (atenolol+/-thiazide-based versus amlodipine+/-perindopril-based therapy) on derived central aortic pressures and hemodynamics.

METHODS AND RESULTS

The CAFE study recruited 2199 patients in 5 ASCOT centers. Radial artery applanation tonometry and pulse wave analysis were used to derive central aortic pressures and hemodynamic indexes on repeated visits for up to 4 years. Most patients received combination therapy throughout the study. Despite similar brachial systolic BPs between treatment groups (Delta0.7 mm Hg; 95% CI, -0.4 to 1.7; P=0.2), there were substantial reductions in central aortic pressures with the amlodipine regimen (central aortic systolic BP, Delta4.3 mm Hg; 95% CI, 3.3 to 5.4; P<0.0001; central aortic pulse pressure, Delta3.0 mm Hg; 95% CI, 2.1 to 3.9; P<0.0001). Cox proportional-hazards modeling showed that central pulse pressure was significantly associated with a post hoc-defined composite outcome of total cardiovascular events/procedures and development of renal impairment in the CAFE cohort (unadjusted, P<0.0001; adjusted for baseline variables, P<0.05).

CONCLUSIONS

BP-lowering drugs can have substantially different effects on central aortic pressures and hemodynamics despite a similar impact on brachial BP. Moreover, central aortic pulse pressure may be a determinant of clinical outcomes, and differences in central aortic pressures may be a potential mechanism to explain the different clinical outcomes between the 2 BP treatment arms in ASCOT.

Influence of arterial compliance on presence and extent of ischaemia during stress echocardiography

OBJECTIVE

To seek an association between total arterial compliance (TAC) and the extent of ischaemia at stress echocardiography.

DESIGN

Cohort study.

SETTING

Regional cardiac centre.

METHODS

255 consecutive patients (147 men; mean (SD) age 58 (8)) presenting for stress echocardiography for clinical indications were studied. Wall motion score index (WMSI) was calculated and ischaemia was defined by an inducible or worsening wall motion abnormality. Peak WMSI was used to reflect the extent of dysfunction (ischaemia or scar), and DeltaWMSI was indicative of extent of ischaemia. TAC was assessed at rest by simultaneous radial applanation tonometry and pulsed wave Doppler in all patients.

RESULTS

Ischaemia was identified by stress echocardiography in 65 patients (25%). TAC was similar in the groups with negative and positive echocardiograms (1.08 (0.41) v 1.17 (0.51) ml/mm Hg, not significant). However, the extent of dysfunction was associated with TAC independently of age, blood pressure, risk factors, and use of a beta blocker. Moreover, the extent of ischaemia was determined by TAC, risk factors, and use of a beta blocker.

CONCLUSION

While traditional cardiovascular risk factors are strong predictors of ischaemia on stress echocardiography, TAC is an independent predictor of the extent of ischaemia.

Relation between aortic stiffness and coronary flow reserve in patients with coronary artery disease

OBJECTIVES

To investigate the relation between aortic stiffness and coronary flow reserve (CFR) in patients with coronary artery disease (CAD).

DESIGN

Observational study.

SETTING

Coronary care unit of a primary care hospital.

PATIENTS

192 consecutive patients who underwent coronary angiography.

MAIN OUTCOME MEASURE

Brachial-ankle pulse wave velocity (ba-PWV), CFR, and severity of CAD.

RESULTS

According to the angiographic findings, patients were divided into four subgroups: patients without significant stenosis (normal coronary artery (NCA) group, n = 28) and those with one vessel disease (1VD group, n = 92), two vessel disease (2VD group, n = 50), or three vessel disease (3VD group, n = 22). ba-PWV increased with the number of diseased vessels and was significantly correlated with the number of diseased vessels (NCA group v 1VD group v 2VD group v 3VD group: 1481 (252) v 1505 (278) v 1577 (266) v 1727 (347) cm/s, p < 0.001). CFR had a significant negative correlation with ba-PWV (r = -0.45, p < 0.0001). The diastolic to systolic velocity ratio obtained in 45 patients also was significantly correlated with ba-PWV (r = -0.35, p < 0.05). Multiple regression analysis showed that ba-PWV was an independent determinant of CFR (p < 0.01).

CONCLUSIONS

Coronary flow is altered with aortic stiffening in patients with CAD. These results suggest one possible mechanism for recent reports that aortic stiffness is a key cardiovascular risk factor.

Increased arterial wave reflections predict severe cardiovascular events in patients undergoing percutaneous coronary interventions

AIMS

Increased arterial wave reflections are associated with the presence and extent of coronary atherosclerosis and with cardiovascular mortality in selected populations. We prospectively evaluated their prognostic value in the short- and long-term following percutaneous coronary interventions (PCIs).

METHODS AND RESULTS

We non-invasively quantified wave reflections [expressed as augmentation index corrected for heart rate of 75 b.p.m. (AIx@75)] using applanation tonometry of the radial artery and a validated transfer function to obtain the corresponding aortic values in 262 patients undergoing PCI. During 2-year follow-up, 61 patients reached the primary endpoint [death, myocardial infarction (MI), and restenosis]. Increasing tertiles of Alx@75 were related to the rate of patients reaching the primary endpoint [15.2, 20 and 35.3%, respectively (P = 0.001)], as well as the secondary endpoints total mortality, myocardial infarction and death plus myocardial infarction (RR for the third vs. the first tertile 4.33, 3.25 and 3.46, respectively, P < 0.05). In a multivariable Cox-regression model, AIx@75 added prognostic value above and beyond clinical risk factors, angiographic variables, and medications (RR 1.8, 95%CI 1.18-2.76 per increasing AIx@75-tertile, P < 0.01).

CONCLUSION

Increased arterial wave reflections are independently associated with an increased risk for severe short- and long-term cardiovascular events in patients undergoing PCI.

Aortic stiffness affects the coronary blood flow response to percutaneous coronary intervention

We examined the hypothesis that a stiff aorta is associated with reduced coronary blood flow (CBF) and CBF response to percutaneous coronary intervention (PCI). Aortic mechanical properties are thought to affect CBF, with increased stiffness associated with decreased coronary perfusion. Animal studies are conflicting, and human evidence is lacking. Even less is known about the effects of aortic stiffness on the CBF response to successful PCI. In 18 subjects undergoing elective PCI, a Doppler velocity guidewire was positioned proximal to a severe coronary stenosis to measure resting and adenosine-induced hyperemic CBF before and after PCI. Stenosis severity was assessed with Doppler velocity and pressure guidewires. Aortic mechanical indexes measured included central pulse-wave velocity (cPWV) and central pulse pressure (cPP). PCI was successful in all subjects (diameter stenosis: 88 +/- 9% to 2 +/- 7%; coronary flow velocity reserve: 1.8 +/- 0.6 to 3.0 +/- 0.8; fractional flow reserve: 0.57 +/- 0.19 to 0.92 +/- 0.06; all P < 0.001). With the adjustment for age and gender, resting and hyperemic CBF were inversely related to cPWV irrespective of the presence of stenosis (resting: before PCI, r2 = 0.452, P < 0.01; after PCI, r2 = 0.261, P = 0.043; hyperemic: before PCI r2 = 0.503, P = 0.005; after PCI r2 = 0.500, P = 0.002), whereas they were related to cPP in absence of stenosis (resting: r2 = 0.368, P = 0.022; hyperemic: r2 = 0.370, P = 0.016). Hyperemic CBF response (P = 0.005) and hyperemic CBF improvement from PCI (P = 0.025) were less marked in a stiff aorta than a compliant aorta. A stiff aorta is associated with a reduction in CBF, a lower hyperemic CBF response, and may reduce the improvement in hyperemic CBF after successful PCI.

Enhanced Aortic Pressure Wave Reflection in Patients After Repair of Aortic Coarctation

BACKGROUND

Despite the relative successes in cardiac surgical repair, early onset of heart disease (hypertension, myocardial infarction, cardiac failure, and sudden death) is a common late complication in patients who have undergone repair of occlusive aortic vessels. Many hypotheses for the cause of this complication have been proposed, but these mechanisms are still controversial.

METHODS

We enrolled 20 patients who had undergone arch repair for coarctation or interruption of the aortic arch. We analyzed the ascending and descending aortic pressure waveforms using a pressure sensor mounted catheter during mid-term or long-term follow-up cardiac catheterization. We compared the pressure waveforms with those of age-matched control subjects who had never undergone aortic arch surgery.

RESULTS

In patients after an arch repair, the inflection time was short (0.095 +/- 0.024 vs 0.19 +/- 0.05 s; p < 0.0001) and the augmentation index increased (27.5 +/- 15.4 vs -3.47 +/- 8.8 %; p < 0.0001). Moreover, they demonstrated high systolic blood pressure (105.2 +/- 12.2 vs 94.7 +/- 11.7 mm Hg; p = 0.0018) and a greater range in pulse pressure variation (40.4 +/- 7.2 vs 32.7 +/- 5.3 mm Hg; p = 0.0004).

CONCLUSIONS

Our results show the early return of the pressure wave reflection and augmented ascending aortic pressure wave in patients after repair of the aortic arch. The elevated ventricular afterload resulting from the enhanced pressure wave reflection may contribute to subsequent late cardiovascular complications (hypertension, myocardial infarction, cardiac failure, and sudden death) in patients after repair of the aortic defects.

Flow-Mediated Dilatation Is Impaired by a High–Saturated Fat Diet but Not by a High-Carbohydrate Diet

Objective— It is unknown whether a low-fat diet, which may elevate triglycerides and lower high-density lipoprotein (HDL) cholesterol, harms the endothelium. Our aim was to determine whether a low-fat, high-carbohydrate (CARB) diet impaired endothelial vasodilation compared with high saturated fat (SFA), monounsaturated fat (MUFA), or polyunsaturated fat (PUFA) diets.

Methods and Results— Forty healthy subjects were randomly crossed over to 4, 3-week isocaloric diets high in PUFA, MUFA, or SFA, containing at least 25 g of the relevant fat or a low-fat, CARB, high–glycemic load diet. Flow-mediated dilatation (FMD), fasting blood lipids, high sensitivity C-reactive protein, plasma intercellular, and vascular adhesion molecules plasma E- and P-selectin were measured after each intervention. SFA impaired FMD compared with all other diets (5.41±2.45% versus 10.80±3.69%; P =0.01). FMD did not change on CARB relative to MUFA or PUFA, despite 23% to 39% rises in triglyceride and 10% to 15% falls in HDL cholesterol. P-selectin was highest after SFA (121±52.7 ng/mL) versus MUFA (98±44.5 ng/mL; P =0.001) and PUFA (96±36.4 ng/mL; P =0.001).

Conclusion— High SFA caused deterioration in FMD compared with high PUFA, MUFA, or CARB diets. Inflammatory responses may also be increased on this diet.

Abnormalities in cardiac baroreceptor sensitivity in acute ischaemic stroke patients are related to aortic stiffness

Cardiac BRS (baroreceptor reflex sensitivity) is impaired following ischaemic stroke and predicts the risk of subsequent long-term death and disability. Impaired cardiac BRS may be due to impaired central processing of baroreceptor information following stroke or reduced baroreceptor activity due to increased large artery stiffness. We evaluated the relationship between large (aortic) artery stiffness and cardiac BRS during the acute phase of ischaemic stroke and in comparison with a group of stroke-free control subjects. Thirty-one ischaemic stroke patients were studied within 48 h of onset and again on day 14, along with 26 control subjects free of cerebrovascular disease. Cardiac BRS (determined by spectral analyses) and arterial stiffness estimated by PWVcf (carotid–femoral pulse wave velocity) using applanation tonometry were obtained. At baseline, cardiac BRS was lower in the stroke compared with the control group (4.3±2.3 compared with 6.5±4.2 ms/mmHg; P<0.05). Cardiac BRS values were correlated with PWVcf at <48 h (r=−0.51, P<0.01) and on day 14 (r=−0.54, P<0.01), but not in the control group (r=−0.27, P=not significant). In quantile regression models, taking into account the effect of all cardiovascular variables, cardiac BRS was independently related to PWVcf at baseline and on day 14 in the stroke patients, but stroke was not related to cardiac BRS level when other cardiovascular variables were considered. Wall stiffness of the arterial vessels involved in the baroreflex arc may account for, at least in part, the reduced cardiac BRS observed in acute stroke patients.

Aortic pressure augmentation predicts adverse cardiovascular events in patients with established coronary artery disease

Pulse pressure (PP), a marker of arterial stiffness, predicts cardiovascular risk. We aimed to determine whether augmentation pressure (AP) derived from the aortic pressure waveform predicts major adverse cardiovascular events (MACE) and death independently of PP in patients with established coronary artery disease (CAD). We prospectively followed-up 297 males undergoing coronary angiography for 1186+/-424 days. Ascending aortic pressure tracings obtained during catheterization were used to calculate AP (difference between the second and the first systolic peak). Augmentation index (AIx) was defined as AP as a percentage of PP. We evaluated whether AP and AIx can predict the risk of MACE (unstable angina, acute myocardial infarction, coronary revascularization, stroke, or death) and death using Cox regression. All models evaluating AP included PP to assess whether AP adds to the information already provided by PP. Both AP and AIx significantly predicted MACE. The hazard ratio (HR) per 10 mm Hg increase in AP was 1.20 (95% confidence interval [CI], 1.08 to 1.34; P<0.001); the HR for each 10% increase in AIx was 1.28 (95% CI, 1.11 to 1.48; P=0.004). After adjusting for other univariate predictors of MACE, age, and other potential confounders, AP remained a significant predictor of MACE (HR per 10 mm Hg increase=1.19; 95% CI, 1.06 to 1.34; P=0.002), as did AIx (adjusted HR, 1.28; 95% CI, 1.09 to 1.50; P=0.003). AP was a significant predictor of death (HR per 10 mm Hg increase=1.18; 95% CI, 1.02 to 1.39; P=0.03). Higher AIx was associated with a trend toward increased mortality (HR=1.22; 95% CI, 0.98 to 1.52; P=0.056). Aortic AP predicts adverse outcomes in patients with CAD independently of PP and other risk markers.

Validation of a new non-invasive portable tonometer for determining arterial pressure wave and pulse wave velocity: the PulsePen device

OBJECTIVE

To validate a new, small portable tonometer (PulsePen) that is able to assess carotid artery pressure and to measure pulse wave velocity (PWV) non-invasively. Its software provides absolute arterial pressure values, an assessment of arterial pulse wave contours, an estimation of reflection waves and measurements of PWV.

DESIGN AND METHODS

Two validation studies were carried out. The aim of the first study was to compare arterial pressure values and pulse wave contours recorded in the carotid artery using the PulsePen versus intra-arterial simultaneous measurements in 10 patients undergoing cardiac catheterization. The pulse wave contour was assessed using Fourier analysis. The comparison between the two methods showed no difference in arterial pressure wave spectral moduli from harmonics 1 to 6. The second study compared PWV measurements taken with the PulsePen (one tonometer) and measurements performed with two Millar tonometers in 68 subjects (32 men, 36 women). PulsePen measurements were realized as two consecutive measurements in the carotid and femoral arteries, both synchronized by electrocardiogram. The pulse wave transit time was calculated as the difference between the time delay of the femoral pulse wave and the carotid pulse wave in relation to the R wave of the electrocardiogram. These measurements were compared with PWV obtained by simultaneous carotid and femoral measurements with the two Millar tonometers. No difference between the two methods was found, with a variation coefficient of 7.7%. The variation coefficients of the inter-observer and intra-observer reproducibility for the PulsePen were 7.9 and 7.2%, respectively.

CONCLUSIONS

These results show that the PulsePen enables an easy and reliable evaluation of central arterial pressure and stiffness in clinical ambulatory practice, especially in high-risk patients in whom arterial stiffness has been shown to be a significant indicator of morbidity and mortality.

Augmentation index, pulse pressure amplification and superoxide anion production in patients with coronary artery disease

BACKGROUND

Free oxygen radicals appear to be involved in several processes that contribute to atherogenesis and increased arterial stiffness.

METHODS

The aim of our study was to evaluate arterial stiffness and the production of superoxide anions by activated polymorphonuclear neutrophils (PMN) obtained from patients with stable coronary artery disease (CAD). Thirty four consecutive patients were studied (21 men, 13 women, mean age 58 years) who underwent coronary angiography. Arterial stiffness was assessed by pulse wave analysis using a validated system (Sphygmocor Mx, AtCor Medical). Superoxide anion production by activated neutrophils was determined by a spectrophotometric method involving the measurement of cytochrome C reduction. The extent of coronary narrowing was estimated by calculation of the Gensini score.

RESULTS

Superoxide anion production by stimulated PMN showed a significant positive correlation with the augmentation index (AIx) and a significant negative correlation with pulse pressure amplification (PPA), (r=0.4, p=0.02; r=-0.5 and p=0.0026 respectively). In multivariable analyses, after adjustment for age, gender and Gensini score, superoxide anions and BMI were significant predictors of AIx (R2=57.37%, p=0.001) and PPA (R2=49.04%, p=0.008). Superoxide anion production was significantly higher in the middle (52.0+/-5.8 nmol O2-/2.5x10(6) PMN/30 min) and upper teriles (62.7+/-5.6) of AIx in comparison with the first tertile 31.8+/-4.1 (p< or =0.05, p< or =0.001). Moreover, superoxide anion production in the highest tertile of PPA was significantly lower (35.6+/-4.3 nmol O2-/2.5x10(6) PMN/30 min) than that in the tertile (60.8+/-6.2, p< or =0.05). Neither the augmentation index nor pulse pressure amplification correlate with the severity of coronary atherosclerosis as indicated by the Gensini score.

CONCLUSIONS

markers of arterial stiffness, AIx and pulse pressure amplification correlate with superoxide anion production but not with the severity of atherosclerosis in coronary arteries.

Aortic Stiffness Is an Independent Predictor of Left Ventricular Function in Patients with Coronary Heart Disease

Although aortic stiffness plays an important role in patients with coronary artery disease (CAD), the influence of aortic stiffness on left ventricular systolic function has not yet been fully evaluated. In the present study, we measured brachial-ankle pulse wave velocity (baPWV), which is a new index of aortic stiffness, in patients with CAD (CAD group, n = 170, 67 +/- 9 years old) and without CAD (non-CAD group, n = 81, 63 +/- 8 years old), and evaluated the relationship between baPWV and left ventricular systolic function in patients with CAD. baPWV in the CAD group was significantly higher than that in the non-CAD group (1,794 +/- 350 vs. 1,469 +/- 292 cm/s, p < 0.05), although both systolic and diastolic blood pressure were comparable between the two groups. In the CAD group, the baPWV was higher in patients with three-vessel disease than that in patients with one-vessel disease (1,885 +/- 542 vs. 1,720 +/- 373 cm/s, p < 0.05). In the CAD group, multivariate analysis demonstrated that baPWV and pulse pressure independently correlated with left ventricular ejection fraction (LVEF). In conclusion, in patients with CAD, baPWV, which is a simple marker of aortic stiffness, increases with CAD severity and correlates with left ventricular systolic function independent of CAD severity.

Beyond blood pressure: pulse wave analysis – a better way of assessing cardiovascular risk?

The study of the pulse pressure wave using the technique of applanation tonometry is becoming more popular as a method of studying vascular stiffness. This review aims to present the uses, potential uses, strengths and weaknesses of the technique of applanation tonometry to assess augmentation index and pulse wave velocity. This article shall briefly discuss the practicalities of applanation tonometry, the physiological factors affecting pulse wave velocity and pulse wave analysis, the changes in pulse wave velocity and pulse wave analysis with pharmacological interventions, and the use of applanation tonometry as a prognostic tool. Although the technique of applanation tonometry seems initially promising, several pertinent issues need to be addressed before it can be used reliably as a clinical tool. Importantly, the technique of applanation tonometry to derive the central waveform from noninvasively-acquired peripheral data needs to be prospectively validated. As stated in this review, the transfer function has been extensively validated using invasive data, whilst noninvasive data estimation of the ascending aortic blood pressure is less accurate.

Large-artery stiffness contributes to the greater prevalence of systolic hypertension in elderly women

OBJECTIVES

To determine whether sex differences in large-artery stiffness contribute to the greater prevalence of systolic hypertension in elderly women than in elderly men.

DESIGN

During a single visit arterial stiffness was assessed in the unmedicated state using four parameters.

PARTICIPANTS

Three hundred seventy-four women with a mean age+/-standard deviation of 72+/-5 and 296 men aged 71+/-5 participated.

SETTING

Hypertensive patients were recruited from general practice as part of the second Australian National Blood Pressure Study in Melbourne, Australia.

MEASUREMENTS

Large-artery stiffness was assessed using multiple methodologies, including aortic arch stiffness (beta-index) using M-mode ultrasound and arterial compliance and augmentation index using noninvasive carotid pressure and aortic flow measurements.

RESULTS

Women had greater carotid and brachial pulse pressure (PP) than men (P<.001), despite higher mean arterial pressure in men. Mean arterial compliance was lower in women (0.20+/-0.12 vs 0.28+/-0.16 mL/mmHg, P<.001) even after correction for aortic area, and aortic arch stiffness was higher (30+/-36 vs 23+/-22; P<.01). Consistent with both a stiffer proximal circulation and a shorter distance to reflection sites, women had higher augmentation index (38+/-11% vs 29+/-12%, P<.001). In multivariate analysis, sex was an independent determinant of all arterial stiffness indices.

CONCLUSION

Independently of known confounders, elderly hypertensive women have stiffer large arteries, greater central wave reflection, and higher PP than elderly men. Stiffer large arteries likely contribute to the greater prevalence of systolic hypertension in elderly women and may partly explain the acceleration in postmenopausal cerebrovascular and cardiac complications.

Non-invasive measures of pulse wave velocity correlate with coronary arterial plaque load in humans

OBJECTIVE

Arterial stiffness is an emerging major risk factor for cardiovascular morbidity and mortality. The aim of the present study was to assess if coronary artery plaque load correlates with non-invasive measures of arterial stiffness.

DESIGN

Prospective investigational study.

SETTING

Tertiary university hospital centre.

PATIENTS

Patients undergoing elective diagnostic coronary angiography.

INTERVENTIONS AND MAIN OUTCOME MEASURES

Coronary artery plaque burden was assessed using a 30 MHz intravascular ultrasound catheter during an automated pullback. Proximal coronary artery plaque volume was determined using a validated edge-detection algorithm following three-dimensional computerized reconstruction. Central arterial stiffness was assessed in each patient using applanation tonometry to radial, carotid and femoral pulses, with derivation of aortic pressure augmentation and pulse wave velocity using pulse wave analysis.

RESULTS

In 35 patients (61 +/- 2 years), proximal coronary arterial plaque volume was 5.9 +/- 0.6 mm3/mm of vessel. Plaque volume correlated positively with carotid-radial pulse wave velocity (r = 0.47, P = 0.008) and appeared to correlate with carotid-femoral pulse wave velocity (r = 0.34, P = 0.07). Aortic augmentation (r = 0.24, P = 0.16), augmentation index (r = 0.3, P = 0.08), and pulse pressure (r = 0.22, P = 0.2) did not correlate significantly with proximal coronary artery plaque volume.

CONCLUSIONS

Non-invasive measures of carotid-radial pulse wave velocity correlate with the extent of coronary artery plaque volume and may be a useful non-invasive surrogate marker for the extent of coronary atherosclerosis. Our findings are consistent with the suggestion that central aortic stiffness may promote the development of coronary atherosclerosis and ischaemic heart disease.

Matrix Metalloproteinase-9 Genotype Influences Large Artery Stiffness Through Effects on Aortic Gene and Protein Expression

Objective— Because large artery stiffening contributes to myocardial ischemia, its determinants are of relevance as potential risk markers. This study examined whether matrix metalloproteinase (MMP)-9 (gelatinase B) genotype is associated with large artery stiffening and aortic MMP-9 gene and protein expression.

Methods and Results— MMP-9 genotype (C-1562T promoter polymorphism) was determined in 84 patients (73 male) with angiographically defined coronary artery disease (CAD). Carotid applanation tonometry was used to assess central blood pressures and, with Doppler velocimetry, to assess aortic stiffness (input and characteristic impedance). Gene expression real-time polymerase chain reaction (RT-PCR) and protein levels (Western blotting) were assessed in relation to genotype in aortic samples from a separate population. T-allele carriers (C/T and T/T) had stiffer large arteries (higher input and characteristic impedance) and higher carotid pulse and systolic blood pressure (all P <0.05) than C/C homozygotes. In aortic samples, gene expression was 5-fold higher and active protein levels were >2-fold higher in T-allele carriers.

Conclusions— Because the T allele was associated with greater MMP-9 mRNA and protein levels, the greater large artery stiffness in T-allele carriers may be secondary to excessive degradation of the arterial elastic matrix. The consequent higher pulse pressure may increase susceptibility to myocardial ischemia.

Arterial stiffness and the systolic hypertension syndrome

PURPOSE OF REVIEW

This review is intended to provide the background for a new comprehensive hemodynamic view of the syndrome of systolic or wide pulse pressure hypertension and its hallmark abnormality: increased central arterial stiffness.

RECENT FINDINGS

Studies of the pathogenesis of systolic hypertension have lagged. This review describes the systolic hypertension syndrome as a complex set of hemodynamic maladaptations that include stiff central arteries, normal peripheral arteries with variable pressure amplification characteristics, arteriolar constriction, microcirculatory rarefaction, metabolic abnormalities, cardiac hypertrophy, and increased blood pressure variability. Because the structural and functional properties of arteries of different caliber are highly heterogeneous and vary with aging and disease, simple measurements such as standard brachial artery blood pressure, brachial pulse pressure, or mean arterial pressure are inadequate to provide meaningful insight into the pathophysiology of the syndrome. Additional parameters developed to describe changes in arterial mechanics (arterial compliance or stiffness, elastic modulus, impedance, pulse wave velocity, augmentation index, and pulse pressure amplification) are intrinsically limited and are directly or indirectly pressure-dependent. Quantitation of central arterial stiffness provides a modest increment in cardiovascular and renal risk stratification.

SUMMARY

Better clinical management of systolic hypertension depends on greater insight into the syndrome as a whole, more critical analysis of existing techniques, and the development of new approaches.

Exercise capacity and heart rate recovery as predictors of coronary heart disease events, in patients with heterozygous Familial Hypercholesterolemia

BACKGROUND

Several clinical and observational studies have established that exercise capacity and activity status are strong predictors of cardiovascular and overall mortality. We aimed to evaluate the relationship between exercise tolerance test (ETT) indices and occurrence of coronary heart disease (CHD), in patients with heterozygous Familial Hypercholesterolemia (eFH).

METHODS

During 1987-1997, we enrolled 639 cardiovascular disease-free patients with heterozygous eFH; 58 (9%) patients were excluded since they had a positive ETT. A fatal or non-fatal CHD event was the end point. Cox proportional hazards models were applied to evaluate the association between the investigated outcome and ETT indices.

RESULTS

During the follow-up (1987-2002), 53 (18%) men and 34 (10%) women developed a CHD event (11 were fatal). The age-adjusted event rate was 87 events per 2915 person-years (3%). Statistical analysis revealed that exercise capacity (hazard ratio = 0.82, P < 0.001), heart rate recovery at 1 min (hazard ratio = 0.91, P < 0.05), and peak pulse pressure levels (hazard ratio = 1.03, P < 0.001), were predictors of CHD, after controlling for several potential confounders.

CONCLUSION

Decreased exercise capacity, a delayed decrease in heart rate during the first minute of graded exercise, and increased peak pulse pressure are strong predictors of coronary events in patients with eFH. Physical activity should be strongly recommended in these patients.

Aortic elastic properties and left ventricular diastolic function in patients with Adamantiades-Behcet's disease

OBJECTIVES

We investigated whether Adamantiades-Behcet's disease (ABD) is related to impaired aortic (Ao) elastic properties and left ventricular (LV) function.

BACKGROUND

Adamantiades-Behcet's disease is an inflammatory disorder characterized by vasculitis leading to vascular complications and, rarely, myocarditis.

METHODS

We studied 82 patients with ABD (age: 40 +/- 12 years) and 24 normal control subjects by echocardiography. Abdominal Ao diameter (mm/m(2)) and Ao elastic indexes--namely, Ao strain (%), distensibility (cm(2) x dyn(-1)x 10(-6)), stiffness index, and pressure strain modulus (Ep) (cm(2) x dyn(-1) x 10(-6))--were calculated from the echocardiographically derived thoracic Ao diameters (mm/m(2)), and the measurement of pulse pressure obtained by cuff sphygmomanometry. Isovolumic relaxation time (IVRT) (ms), deceleration time (DT) (ms), and flow propagation velocity (FPV) (cm/s) were measured by Doppler echocardiography to assess diastolic LV function. The duration of disease and presence of vascular complications were noted.

RESULTS

Patients versus control subjects had increased Ao diameters (p < 0.01), lower mean Ao strain and distensibility (4 vs. 9 and 1.4 vs. 3.4, respectively, p < 0.01), higher mean aortic stiffness index and Ep (15.6 vs. 6 and 1.17 vs. 0.44, respectively, p < 0.01), and impaired IVRT and FPV (p < 0.01). Aortic function indexes were related to the duration of disease (p < 0.01) and increased DT (p < 0.01). Deceleration time >190 ms predicted vascular complications with 80% sensitivity and 71% specificity (odds ratio 6.52 [confidence interval: 2.23 to 19.03]).

CONCLUSION

Aortic elastic properties and diastolic LV function are impaired in patients with ABD and are interrelated. The link between diastolic LV dysfunction and vascular complications suggests the presence of a common pathophysiologic pathway and provides a possible marker of risk for vascular disease.

Usefulness of the Monkey Model to Investigate the Role of Soy in Postmenopausal Women's Health

Some of the important health issues for postmenopausal women include cardiovascular disease, osteoporosis, breast cancer, and relief of menopausal symptoms. Ovariectomized cynomolgus monkeys (Macaca fascicularis) have many strengths as models for research in this area including a close phylogenetic relationship to humans, similarities in lipid/lipoprotein metabolism and coronary artery anatomy, similar skeletal anatomical and morphological characteristics, mammary glands with similar pathophysiological characteristics, and a 28-day menstrual cycle with similar hormonal fluctuations. Monkeys (macaques) also experience declining ovarian function and irregular menstrual cycles (natural menopause) when they approach 24 to 29 yr of age. However, because of their very short life span after natural menopause, ovariectomized macaques are used to model postmenopausal women. The cynomolgus monkey model has been useful in defining the potential cardiovascular benefits of soy foods and soy supplements; however, it remains unclear whether the observations are generalizable to all women or only to those who, like cynomolgus monkeys, convert the soy isoflavone daidzein to the metabolite equol. Particularly important has been the use of the cynomolgus monkey model to understand the effects of soy on breast health. There is evidence from a cynomolgus monkey trial to suggest that soy/soy phytoestrogens have no estrogen agonist effects for breast. Finally, soy/soy phytoestrogens do not appear to be an adequate alternative to postmenopausal hormone therapy. Nevertheless, important attributes of soy have been identified, and it may have potential as a complementary component to hormone therapy.

Matrix metalloproteinase-3 genotype contributes to age-related aortic stiffening through modulation of gene and protein expression

Matrix metalloproteinases (MMPs) include most major constituents of the arterial wall as substrates. A common promotor polymorphism (5A/6A) is associated with differences in MMP-3 (stromelysin-1) activity, and associations with certain forms of vascular disease have been shown. This study investigated whether the MMP-3 5A/6A promoter polymorphism contributes to age-related large artery stiffening. MMP-3 5A/6A genotype was determined in 203 (135 male) low cardiovascular risk, unmedicated individuals who were divided prospectively into two groups (30 to 60 years, n=126; > or =61 years, n=77). Noninvasive large artery stiffness was measured as ascending aortic input impedance from brachial blood pressure, carotid tonometry, and Doppler ascending aortic blood flow. In the older group, homozygotes had higher aortic input (P<0.01) and characteristic (P<0.01) impedance, ie, higher stiffness, than heterozygotes after correction for the effects of age, gender, and mean arterial pressure. There was no such difference in the younger group. Gene expression was subsequently investigated in dermal biopsies in randomly selected older men from the same cohort with real-time PCR (n=40). In 5A homozygotes, gene expression was 4-fold higher (P<0.05), and in 6A homozygotes, 2-fold lower (P<0.05) compared with the heterozygotes. Differences in gene expression were associated with corresponding significant changes in MMP-3 protein levels. Concordance between dermal and aortic gene and protein expression was shown in a separate cohort of postmortem aortic samples (n=7). We conclude that MMP-3 genotype may be an important determinant of vascular remodeling and age-related arterial stiffening, with the heterozygote having the optimal balance between matrix accumulation and deposition.

Noninvasive assessment of arterial stiffness and risk of atherosclerotic events

Investigation of arterial stiffness, especially of the large arteries, has gathered pace in recent years with the development of readily available noninvasive assessment techniques. These include the measurement of pulse wave velocity, the use of ultrasound to relate the change in diameter or area of an artery to distending pressure, and analysis of arterial waveforms obtained by applanation tonometry. Here, we describe each of these techniques and their limitations and discuss how the measured parameters relate to established cardiovascular risk factors and clinical outcome. We also consider which techniques might be most appropriate for wider clinical application. Finally, the effects of current and future cardiovascular drugs on arterial stiffness are also discussed, as is the relationship between arterial elasticity and endothelial function.