Transport in rat vessel walls. I. Hydraulic conductivities of the aorta, pulmonary artery, and inferior vena cava with intact and denuded endothelia

In this study, filtration flows through the walls of the rat aorta, pulmonary artery (PA), and inferior vena cava (IVC), vessels with very different susceptibilities to atherosclerosis, were measured as a function of transmural pressure (ΔP), with intact and denuded endothelium on the same vessel. Aortic hydraulic conductivity ( Lp) is high at 60 mmHg, drops ∼40% by 100 mmHg, and is pressure independent to 140 mmHg. The trends are similar in the PA and IVC, dropping 42% from 10 to 40 mmHg and flat to 100 mmHg (PA) and dropping 33% from 10 to 20 mmHg and essentially flat to 60 mmHg (IVC). Removal of the endothelium renders Lp(ΔP) flat: it increases Lp of the aorta by ∼75%, doubles Lp of the PA, and quadruples Lp of the IVC. Specific resistance (1/ Lp) of the aortic endothelium is ∼47% of total resistance; i.e., the endothelium accounts for ∼47% of the ΔP drop at 100 mmHg. The PA value is 55% at >40 mmHg, and the IVC value is 23% at 10 mmHg. Lp of the intact aorta, PA, and IVC are order 10−8, 10−7, and 5 × 10−7 cm·s−1·mmHg−1, and wall thicknesses are 145.8 μm (SD 9.3), 78.9 μm (SD 3.3), and 66.1 μm (SD 4.1), respectively. These data are consistent with the different wall structures of the three vessels. The rat aortic Lp data are quantitatively consistent with rabbit Lp(ΔP) (Tedgui A and Lever MJ. Am J Physiol Heart Circ Physiol 247: H784–H791, 1984; Baldwin AL and Wilson LM. Am J Physiol Heart Circ Physiol 264: H26–H32, 1993), suggesting that intimal compression under pressure loading may also play a role in Lp(ΔP) in these other vessels. Despite very different driving ΔP, nominal transmural water fluxes of these three vessels are very similar and, therefore, cannot alone account for their differences in disease susceptibility. The different fates of macromolecular tracers convected by these water fluxes into the walls of these vessels may account for this difference.

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Gas Tensions in the Lungs and Major Blood Vessels of the Urodele Amphibian, Amphiuma Tridactylum

Journal of Experimental Biology ◽

10.1242/jeb.55.1.47 ◽

1971 ◽

Vol 55 (1) ◽

pp. 47-61

Author(s):

DANIEL P. TOEWS ◽

G. SHELTON ◽

D. J. RANDALL

Keyword(s):

Carbon Dioxide ◽

Pulmonary Artery ◽

Inferior Vena Cava ◽

Blood Vessels ◽

Pulmonary Vein ◽

Oxygen Tension ◽

Inferior Vena ◽

Vena Cava ◽

Dorsal Aorta ◽

Oxygen Tensions

1. Oxygen and carbon dioxide tensions were determined in the lungs and in blood from the dorsal aorta, pulmonary vein, pulmonary artery and inferior vena cava in the intact, free swimming, Amphiuma. At 15° C this animal was submerged for a large part of the time and surfaced briefly to breathe at variable time intervals, the mean period being 45 min. 2. Oxygen tensions in the lungs and in all blood vessels oscillated with the breathing cycles, falling gradually during the period of submersion and rising rapidly after the animal breathed. The absolute level of oxygen tension did not appear to constitute the effective signal beginning or ending a series of breathing movements. 3. A small oxygen gradient existed between lungs and blood in the pulmonary vein immediately after a breath. The gradient increased in size as an animal remained submerged due, it is suggested, to lung vasoconstriction increasing the transfer factor. 4. Blood in the dorsal aorta had a lower oxygen tension than that in the pulmonary vein. A right-to-left shunt occurred as blood moved through the heart. The degree of shunting increased as the animal remained submerged and pulmonary vasoconstriction occurred. Left-to-right shunt was relatively insignificant since oxygen tensions in the inferior vena cava and pulmonary artery were very similar. 5. Carbon dioxide tensions were relatively constant during the breathing-diving cycle since Amphiuma removed almost all of this gas through the skin.

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1099 Constrictive pericarditis:a challenge in Cardiology

European Heart Journal - Cardiovascular Imaging ◽

10.1093/ehjci/jez319.648 ◽

2020 ◽

Vol 21 (Supplement_1) ◽

Author(s):

C Kairis ◽

C Stefanidis ◽

B Saxpekidis ◽

C Petridis ◽

L Mosialos ◽

...

Keyword(s):

Radiation Therapy ◽

Pulmonary Artery ◽

Inferior Vena Cava ◽

Right Ventricle ◽

Cardiac Catheterization ◽

Constrictive Pericarditis ◽

Inferior Vena ◽

Vena Cava ◽

Permanent Pacemaker ◽

Right Heart

Abstract Funding Acknowledgements none A 50-year old woman had complained about dyspnea and leg swelling despite taking furosemide 80 mgr per day. Her past medical history had included radiation therapy for Hodgkin"s lymphoma, prosthetic heart valves (mechanical MV, AV- INR = 3,2) and permanent pacemaker. Also her coronary vessels were normal. On clinical examination she was non-febrile, the arterial pressure was 120/80mmHg,there was atrial fibrillation at 70 pulses/min at rest and oxygen saturation was 96%. The chest x-ray finding was left pleural effusion. The patient also had ascites. Kidney function was normal without proteinuria. The diagnostic paracentesis and biochemical analysis of ascitic fluid was indicative of transudative fluid.Cytologic analysis was negative for malignancy. Moreover,needle biopsy specimen was subjected to histopathology,which was negative for malignancy. Echocardiography had revealed normal size and function of left ventricle ( LV = 46mm-EF = 60%). The mechanical valves had normal function, without paravalvular leak or masses. Also right ventricle was normal. The pulmonary artery pressure measured by echocardiography was in the normal range (RVSP = 35mmHg), but the inferior vena cava was dilated.There were also dilated hepatic veins and hepatic vein flow reversal.There was variation> 25% in triscupid inflow with respiration. TEE had confirmed the findings of transthoracic echo with regard of prosthetic valves. CT of chest and abdomen findings were no pathologic lymphadenopathy,no pulmonary embolism and absence of tumor compressing inferior vena cava. Chest CT scan had demonstrated pericardium thickening,indicative of constrictive pericarditis. CMR was not performed because of permanent pacemaker. The final step in diagnostic algorithm was cardiac catheterization: a)the pulmonary artery systolic pressure measured during right heart catheterization was 35mmHg. b)dip & plateau’ pattern or ‘square root sign of right ventricle, i.e. pattern of accentuated early dip in diastolic pressure, followed by plateauing in mid-late diastole. c)prominent y wave of right atrium- absent x wave because of AF. d)left ventriculography was not performed because of mechanical aortic valve. At the end constrictive pericarditis was confirmed by the surgical report. According to ESC guidelines a diagnosis of constrictive pericarditis is based on the association of signs and symptoms of right heart failure and impaired diastolic filling due to pericardial constriction by one or more imaging methods, including echocardiography, CT, CMR, and cardiac catheterization. However,the most important step is the suspicion of constrictive pericarditis, especially in patients with history of radiation therapy and heart surgery. Abstract 1099 Figure.

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