Pulmonary arterial hypertension (PAH) is a disease of the small vessels in which there is a substantial increase in pulmonary vascular resistance leading to right ventricle failure and death. Invasive haemodynamic evaluation is mandatory not only for diagnosis confirmation but also to address prognosis and eligibility for the use of calcium-channel blockers through an acute vasodilator challeng...

OBJECTIVE We aimed to investigate whether aortic elastic properties were affected in subclinical hypothyroidism (SCH) by using tissue Doppler imaging (TDI). SUBJECTS AND METHODS Forty-three patients with newly diagnosed SCH and forty-eight healthy controls were included to the study. Systolic and diastolic diameters of the ascending aorta were measured by M-mode transthoracic echocardiography...

Cardiovagal baroreflex sensitivity (cvBRS) measures the efficiency of the cardiovagal baroreflex to modulate heart rate in response to increases or decreases in systolic blood pressure (SBP). Given that baroreceptors are located in the walls of the carotid sinuses (CS) and aortic arch (AA), the arterial mechanics of these sites are important contributors to cvBRS. However, the relative contribu...

Studies in animals and humans suggest that sympathetic activity exerts a stiffening influence on large and middle-sized artery walls. We sought to obtain further evidence on this issue by measuring radial artery distensibility in an allotransplanted and thus denervated hand using the contralateral artery as control. In 2 men, blood pressure was measured by a semiautomatic device (Dinamap). Dias...

PURPOSE To use a volume-selective 3D turbo spin echo (TSE) technique to image the carotid artery wall and measure distensibility. MATERIALS AND METHODS A high-resolution volume-selective 3D TSE sequence has been developed. Volume selection is accomplished by orthogonal gradients for the 90 degrees and 180 degrees excitations and allows a 3D volume of vessel wall to be imaged in a relatively s...

THE IMPORTANCE of the carotid and aortic baroreceptors in the reflex control of heart rate, peripheral vascular resistance, and myocardial contractility is well appreciated. It has long been suspected that an important additional factor in circulatory regulation is the distensibility and capacity of the venous bed." The multiple circulatory effects of the baroreceptors have made precise study o...

BACKGROUND Noninvasive diagnosis of pulmonary hypertension (PH) primarily relies upon Doppler echocardiography of tricuspid regurgitation (TR). However, TR might be absent or difficult to measure. HYPOTHESIS/OBJECTIVES To determine the diagnostic value of right pulmonary artery distensibility (RPAD) index for prediction of Doppler-derived estimates of pulmonary artery (PA) pressure compared t...

The purpose of this investigation was to assess the interactive influence of sympathetic activation and supplemental nitric oxide (NO) on brachial artery distensibility vs. its diameter. It was hypothesized that 1) sympathetic activation and NO competitively impact muscular conduit artery (brachial artery) mechanics, and 2) neurogenic constrictor input affects conduit vessel stiffness independe...

Baroreceptor resetting during hypertension has been attributed to a reduction in the distensibility of the vessel wall in which the receptors are located. According to this hypothesis, a simple increase in pressure is all that is required to overcome the increase in vessel wall stiffness. However, previous work from our laboratory suggested a more complicated situation. Measurements of both ves...

In the anesthetized rat, acute increases in heart rate are accompanied by a reduction in arterial distensibility, which is a significant phenomenon in elastic-type vessels such as the common carotid but much less evident in muscle-type vessels such as the femoral artery. Because the sympathetic nervous system importantly reduces arterial distensibility, the present study aimed to determine whet...