Association of left ventricular motion and central augmentation index in healthy young men.

Background: Central blood pressure is a determinant of cardiovascular outcome; however, it can be described by parameters other than systolic and diastolic pressure with central augmentation index (AIx) often utilized. Although generally considered as determined by peripheral pressure wave reflection, not all data are consistent with this interpretation of AIx. We hypothesized that the motion of the heart during systole may influence central pressure waveform morphology, including the AIx.

Computed tomography stress myocardial perfusion imaging in patients considered for revascularization: a comparison with fractional flow reserve.

Aims: Adenosine stress computed tomography myocardial perfusion imaging (CTP) is an emerging non-invasive method for detecting myocardial ischaemia. Its value when compared with fractional flow reserve (FFR), a highly accurate index of ischaemia, is unknown. Our aim was to determine the diagnostic accuracy of CTP and its incremental value when used with computed tomography coronary angiography (CTA) for detecting ischaemia compared with FFR.

Increased sympathetic activity in children with obstructive sleep apnea: cardiovascular implications.

Background: Obstructive sleep apnea (OSA) is associated with increased sympathetic activity and hypertension in adults. We tested the hypothesis that children with OSA also have increased sympathetic activity as measured by overnight urinary catecholamines, and that this increase is related to the severity of OSA and to blood pressure (BP).

Methods: Seventy snoring children referred for assessment of sleep disordered breathing and 26 healthy non-snoring control children (age range: 3-12 years, 59 M/37 F) were studied.

Diagnostic accuracy of noninvasive coronary angiography with 320-detector row computed tomography.

We sought to evaluate the diagnostic accuracy of noninvasive coronary angiography using 320-detector row computed tomography, which provides 16-cm craniocaudal coverage in 350 ms and can image the entire coronary tree in a single heartbeat, representing a significant advance from previous-generation scanners. We evaluated 63 consecutive patients who underwent 320-detector row computed tomography and invasive coronary angiography for the investigation of suspected coronary artery disease. Patients with known coronary artery disease were excluded.

The heart rate response to spontaneous arousal from sleep is reduced in children with Down syndrome referred for evaluation of sleep-disordered breathing.

Arousal from sleep in healthy adults is associated with a large, transient increase in heart rate (HR). Individuals with Down syndrome (DS) have attenuated cardiovascular responses to autonomic tests during wakefulness. We tested the hypothesis that the HR response to arousal from sleep is reduced in children with DS and obstructive sleep apnea (OSA) compared with healthy children.

Cardiovascular magnetic resonance-derived aortic distensibility: validation and observed regional differences in the elderly.

Objective: Applanation tonometry evaluation of pulse wave velocity is widely accepted as the 'gold standard' method for noninvasively assessing arterial stiffness. Newer noninvasive tools such as cardiovascular magnetic resonance can also evaluate arterial stiffness, but have not been validated. The aim of this study was to validate cardiovascular magnetic resonance-derived aortic distensibility with pulse wave velocity and to investigate age-related changes in regional aortic distensibility.

Arterial transfer functions and the reconstruction of central aortic waveforms: myths, controversies and misconceptions.

Continuing reports in the literature regarding the potential of central pulse wave analysis in clinical practice and a recent consensus statement demonstrate the increasing interest in the clinical application of arterial transfer functions. A number of misconceptions, however, persist regarding their use. In spite of ongoing controversy, there are considerable published data that would permit users to assess the validity and accuracy of the technique.

Arterial pulse wave velocity but not augmentation index is associated with coronary artery disease extent and severity: implications for arterial transfer function applicability.

Objectives: The aim of this study was to test the hypothesis that coronary artery disease extent and severity are associated with central aortic pressure waveform characteristics.

Background: Although it is thought that central aortic pressure waveform characteristics, particularly augmentation index, may influence cardiovascular disease progression and predict cardiovascular risk, little is known of the relationship between central waveform characteristics and the severity and extent of coronary artery disease.

Methods: Central aortic waveforms (2F Millar pressure transducer-tipped catheters) were acquired at the time of coronary angiography for suspected native coronary artery disease in 40 patients (24 male).

'Generalizability' of a radial-aortic transfer function for the derivation of central aortic waveform parameters.

Objective: Arterial transfer functions (TFs) describe the relationship between the pressure waveform at different arterial sites. Generalized TFs are used to reconstruct central aortic waveforms from non-invasively obtained peripheral waveforms and have been promoted as potentially clinically useful. A limitation is the paucity of information on their 'generalizability' with no information existing on the number of subjects required to construct a satisfactory TF, nor is adequate prospective validation available.

Drug effects on the mechanical properties of large arteries in humans.

1. Arteries become stiffer with increasing age and various disease states. A complete description of arterial mechanical properties in vivo is not possible, although a number of methods have been used.

Formation of ovarian follicular fluid may be due to the osmotic potential of large glycosaminoglycans and proteoglycans.

During mammalian follicle development, a fluid-filled antrum develops in the avascular centre of the follicle. We investigated the hypothesis that follicular fluid contains osmotically-active molecules, sufficiently large so as to not freely escape the follicular fluid. Such molecules could generate an osmotic differential and thus recruit fluid from the surrounding vascularised stroma into the antrum.

Acute and chronic effects of flavanol-rich cocoa on vascular function in subjects with coronary artery disease: a randomized double-blind placebo-controlled study.

Evidence suggests that flavonoid-containing diets reduce cardiovascular risk, but the mechanisms responsible are unclear. In the present study, we sought to determine the effect of flavanol-rich cocoa on vascular function in individuals with CAD (coronary artery disease). Forty subjects (61+/-8 years; 30 male) with CAD were recruited to a 6-week randomized double-blind placebo-controlled study.

Transcatheter coil occlusion of coronary artery to right ventricular fistulae in pulmonary atresia with intact ventricular septum.

We describe a young adult with an underlying diagnosis of pulmonary atresia with intact ventricular septum and Fontan physiology who presented with extreme dyspnoea on exertion. Coronary artery to right ventricular fistulae and reversible myocardial ischaemia secondary to a right ventricular steal phenomenon were present. The right coronary artery to right ventricular fistula was completely occluded with coils, by a transcoronary approach, with amelioration of symptoms.

Systemic inflammatory markers in acute coronary syndrome: association with cardiovascular risk factors and effect of early lipid lowering.

Background: Evidence for statin therapy in prevention of coronary artery disease is overwhelming. In spite of theoretical benefits, any additional advantage of its early introduction in the management of acute coronary syndrome is, however, uncertain. We therefore investigated differences between plasma levels of the systemic inflammatory markers intercellular adhesion molecule-1, vascular cell adhesion molecule-1, E-selectin, C-reactive protein and interleukin-6 in patients presenting with unstable angina or acute myocardial infarction, and assessed whether the 30-day levels of these markers are influenced by early instigation of the HMG-CoA reductase inhibitor pravastatin.

Waveform dispersion, not reflection, may be the major determinant of aortic pressure wave morphology.

The objective of this study was to investigate the determinants of aortic pressure waveform morphology in the thoracoabdominal aorta with specific reference to features of potential prognostic value for cardiovascular disease. In particular, we aimed to determine the location of major pressure wave reflection sites within the aorta. Aortic pressure waveforms were acquired with 2-Fr Millar Mikro-tip catheter transducers in 40 subjects (26 men, 14 women), and repeated in 10 subjects, at five predetermined points within the aorta: aortic root, transverse arch, and at the levels of the diaphragm, renal arteries, and aortic bifurcation.

Effect of non-invasive calibration of radial waveforms on error in transfer-function-derived central aortic waveform characteristics.

Transfer function techniques are increasingly used for non-invasive estimation of central aortic waveform characteristics. Non-invasive radial waveforms must be calibrated for this purpose. Most validation studies have used invasive pressures for calibration, with little data on the impact of non-invasive calibration on transfer-function-derived aortic waveform characteristics.

Use of arterial transfer functions for the derivation of central aortic waveform characteristics in subjects with type 2 diabetes and cardiovascular disease.

Objective: Optimal blood pressure control in subjects with diabetes reduces cardiovascular complications. There is theoretical benefit in the assessment of central aortic waveforms including the augmentation index, which is taken as a putative index of stiffness. Transfer functions may be used to reconstruct aortic from radial pressure waveforms; however, a single generalized transfer function may not be appropriate for all patients.

Use of arterial transfer functions for the derivation of aortic waveform characteristics.

Objective: To investigate the utility and accuracy of radial-aortic arterial transfer functions for the derivation of central blood pressure waveforms. DESIGN Prospective measurement of central and peripheral waveforms in patients undergoing coronary angiography or percutaneous coronary intervention.

Methods: Simultaneous invasive central aortic and non-invasive radial pressure waveforms were recorded in 78 subjects (61 male : 17 female).