Arterial mechanics in the fin whale suggest a unique hemodynamic design

1994 ◽  
Vol 267 (3) ◽  
pp. R805-R818 ◽  
Author(s):  
R. E. Shadwick ◽  
J. M. Gosline

An analysis of the dimensions of the aortic tree and the mechanical properties of arterial wall tissues in the fin whale (Balaenoptera physalus) is presented. The aortic arch is greatly expanded, having an internal radius at an estimated mean blood pressure (13 kPa) that is 2.5 times greater than that of the descending thoracic aorta. At this pressure, the elastic modulus of the arch wall (0.4 MPa) is 30 times less than that of the descending aorta (12 MPa). Consequently, even though some capacitance is provided anteriorly by the relatively compliant innominate and carotid arteries, > 90% of the arterial capacitance resides in the arch. The characteristic pressure wave velocity (C0) and impedance (Z0) were calculated from vessel dimensions and elasticity. A predicted 20-fold increase in Z0 between the arch and thoracic aorta should provide a major reflecting site, effectively uncoupling the arch from the remainder of the arterial tree. The dimensions of the arch relative to the likely pressure wavelengths within it suggest that it acts like a compliant windkessel that greatly reduces the pulsatility of the inflow to the descending aorta, which itself likely acts as a rigid, tapered manifold. It is suggested that the presence of both a highly compliant arch and a relatively rigid descending aorta is an adaptation for diving.

1996 ◽  
Vol 199 (4) ◽  
pp. 985-997 ◽  
Author(s):  
J M Gosline ◽  
R E Shadwick

The aortic arch and the descending aorta in the fin whale (Balaenoptera physalus) are structurally and mechanically very different from comparable vessels in other mammals. Although the external diameter of the whale's descending thoracic aorta (approximately 12 cm) is similar to that predicted by scaling relationships for terrestrial mammals, the wall thickness:diameter ratio in the whale (0.015) is much smaller than the characteristic value for other mammals (0.05). In addition, the elastic modulus of the thoracic aorta (12 MPa at 13 kPa blood pressure) is about 30 times higher than in other mammals. In contrast, the whale's aortic arch has a wall thickness/diameter ratio (0.055) and an elastic modulus (0.4 MPa) that are essentially identical to those for other mammals. However, the aortic arch is unusual in that it can be deformed biaxially to very large strains without entering a region of high stiffness caused by the recruitment of fully extended collagen fibres. Chemical composition studies indicate that the elastin:collagen ratio is high in the aortic arch (approximately 2:1) and that this ratio falls in the thoracic (approximately 1:2) and abdominal (approximately 1:3) aortas, but the magnitude of the change in composition does not account for the dramatic difference in mechanical properties. This suggests that there are differences in the elastin and collagen fibre architecture of these vessels. The descending aorta contains dense bands of tendon-like, wavy collagen fibres that run in the plane of the arterial wall, forming a fibre-lattice that runs in parallel to the elastin lamellae and reinforces the wall, making it very stiff. The aortic arch contains a very different collagen fibre-lattice in which fibres appear to have a component of orientation that runs through the thickness of the artery wall. This suggests that the collagen fibres may be arranged in series with elastin-containing elements, a difference in tissue architecture that could account for both the lower stiffness and the extreme extensibility of the whale's aortic arch. Thus, both the structure and the mechanical behaviour of the lamellar units in the aortic arch and aorta of the whale have presumably been modified to produce the unusual mechanical and haemodynamic properties of the whale circulation.


A survey has been made in adult dogs of the collagen and elastin content of the walls of arteries varying in size from the thoracic aorta to the saphenous artery. In all arteries, except the smallest, collagen and elastin together formed about 50% of the dry weight. In the smallest the proportion was somewhat higher. On the basis of relative proportions of elastin and collagen the systemic arterial tree was found to be divided rather sharply into two regions: in the intrathoracic aorta there was about twice as much elastin as collagen in the wall; in all other vessels the relation was reversed, there being about twice as much collagen as elastin. The transition between the more elastic intrathoracic aorta and the more collagenous extrathoracic vessels was abrupt and took place over a distance of only 5 cm or so. The pulmonary artery resembled the extrathoracic vessels rather than the thoracic aorta in ratio of elastin to collagen. Newborn and young puppies showed a similar difference to adults between thoracic and abdominal aorta, although we did not investigate the relation between the two vessels in detail.


1987 ◽  
Vol 67 (6) ◽  
pp. 906-914 ◽  
Author(s):  
Terry Lichtor ◽  
Harry R. Davis ◽  
Lydia Johns ◽  
Draga Vesselinovitch ◽  
Robert W. Wissler ◽  
...  

✓ Morphometric and chemical changes in the arterial wall were studied after 12 months of diet-induced atherosclerosis in rhesus monkeys treated with either bilateral surgical thoracic sympathectomy or propranolol. There was a marked reduction in the progression of atherosclerosis in the carotid arteries and a moderate reduction in the disease found in the thoracic aorta of monkeys treated initially with a sympathectomy, in comparison to control monkeys fed an atherogenic diet alone. Propranolol at a dose of 40 mg/12 hrs also seemed to reduce the progression of atherosclerosis in the carotid arteries and thoracic aorta, although the differences were less dramatic. There were minimal differences in the extent of atherosclerosis in the abdominal aorta or femoral arteries of animals in either treatment group as compared with the control group. Similarly, the chemical composition of these same major vessels showed no significant differences. Therefore, in the face of severe atherogenic stimuli, chemical or surgical sympathectomy may be useful in controlling atherosclerosis in specific arterial beds.


VASA ◽  
2005 ◽  
Vol 34 (3) ◽  
pp. 181-185 ◽  
Author(s):  
Westhoff-Bleck ◽  
Meyer ◽  
Lotz ◽  
Tutarel ◽  
Weiss ◽  
...  

Background: The presence of a bicuspid aortic valve (BAV) might be associated with a progressive dilatation of the aortic root and ascending aorta. However, involvement of the aortic arch and descending aorta has not yet been elucidated. Patients and methods: Magnetic resonance angiography (MRA) was used to assess the diameter of the ascending aorta, aortic arch, and descending aorta in 28 patients with bicuspid aortic valves (mean age 30 ± 9 years). Results: Patients with BAV, but without significant aortic stenosis or regurgitation (n = 10, mean age 27 ± 8 years, n.s. versus control) were compared with controls (n = 13, mean age 33 ± 10 years). In the BAV-patients, aortic root diameter was 35.1 ± 4.9 mm versus 28.9 ± 4.8 mm in the control group (p < 0.01). The diameter of the ascending aorta was also significantly increased at the level of the pulmonary artery (35.5 ± 5.6 mm versus 27.0 ± 4.8 mm, p < 0.001). BAV-patients with moderate or severe aortic regurgitation (n = 18, mean age 32 ± 9 years, n.s. versus control) had a significant dilatation of the aortic root, ascending aorta at the level of the pulmonary artery (41.7 ± 4.8 mm versus 27.0 ± 4.8 mm in control patients, p < 0.001) and, furthermore, significantly increased diameters of the aortic arch (27.1 ± 5.6 mm versus 21.5 ± 1.8 mm, p < 0.01) and descending aorta (21.8 ± 5.6 mm versus 17.0 ± 5.6 mm, p < 0.01). Conclusions: The whole thoracic aorta is abnormally dilated in patients with BAV, particularly in patients with moderate/severe aortic regurgitation. The maximum dilatation occurs in the ascending aorta at the level of the pulmonary artery. Thus, we suggest evaluation of the entire thoracic aorta in patients with BAV.


VASA ◽  
2009 ◽  
Vol 38 (3) ◽  
pp. 263-266 ◽  
Author(s):  
Yuan ◽  
Tager

Penetrating atherosclerotic ulcer of the aorta is uncommon, and usually develops in the descending thoracic aorta. Rarely this condition involves the branch vessels of the aorta. We report a case of ruptured aneurysm of the innominate artery resulting from penetrating atherosclerotic ulcer. Open surgery was the treatment of choice for the ruptured aneurysm, while conservative treatment was recommended for the associated penetrating atherosclerotic ulcers of the descending aorta.


2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
W Sato ◽  
Y Kobayashi ◽  
M Otaka ◽  
M Unuma ◽  
T Yamanaka ◽  
...  

Abstract Background Vascular inflammation plays a fundamental role in most vascular diseases including atherosclerosis and vasculitis syndrome, in which arterial wall vascularization (AWV) frequently develops. Visualization of AWV is informative in detecting the vascular inflammation but is challenging. A new ultrasound technique (superb micro-vascular imaging [SMI]) allows the detection of extremely low-velocity flows. We examined an availability of SMI for assessment of the instability of atherosclerotic plaques and the activity of Takayasu arteritis (TA). Methods and results The study consists of two independent and consecutive parts A and B, examined in carotid stenosis (A) and TA (B), respectively. In part A, 12 patients with symptomatic severe carotid stenosis (CS group) scheduled for carotid endarterectomy were enrolled. In six of 12 patients, preoperative ultrasonography with SMI showed intraplaque neovascularization at the plaque shoulder. Postoperatively, histopathology confirmed the neovessels at the corresponding sites of visualized AWV. SMI had a sensitivity of 67%, specificity of 90% for detection of AWV in CS group. In SMI analysis, false positive findings were caused by motion artifact and arterial wall calcification, and a false negative finding is attributed by intraplaque hemorrhage. In part B, 10 patients with TA were enrolled. All patients underwent 18F-FDG-PET/CT, and its vascular uptake were compared with AWV detected by SMI. Bilateral common carotid arteries (CCA), internal carotid arteries and common iliac arteries were examined by SMI. Active vascular 18F-FDG uptake (max SUV &gt;2.1) were found at five sites in three patients, which were not significantly correlated with the prevalence of macaroni sign, increase in C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). Of note, SMI revealed AWV at five sites corresponding to uptake of 18F-FDG, with a sensitivity/specificity of 100% and 98%, positive predictive value 71%, and a negative predictive value 100%. Conclusion SMI enables visualization of AWV at vulnerable plaque in CS patients and at 18F-FDG positive sites in TA patients. SMI has potential as a modality to detect the vascular inflammation. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Grant-in-Aid for Scientific Research, Japan


2017 ◽  
Vol 3 ◽  
Author(s):  
LAETITIA LEMPEREUR ◽  
MORGAN DELOBELLE ◽  
MARJAN DOOM ◽  
JAN HAELTERS ◽  
ETIENNE LEVY ◽  
...  

SUMMARY On 9 November 2015, a juvenile male fin whale of 11·60 m length was observed on the bulb of a merchant vessel in the Channel Terneuzen – Ghent (The Netherlands – Belgium). A severe parasitosis was present in the right heart ventricle and caudal caval vein. Parasites were identified as Crassicauda boopis based on macroscopic and microscopic observations. The sequence of the 18S rRNA gene obtained from the parasite samples was 100% similar to the sequence of the 18S rRNA gene from Crassicauda magna available on GenBank. While adults of C. boopis and C. magna are morphologically distinct and found at different locations in the body, the molecular analysis of the 18S rRNA gene seems insufficient for reliable species identification. Although numerous C. boopis were found, the cause of death was identified as due to the collision with the ship, as suggested by the presence of a large haematoma, and the absence of evidence of renal failure. The young age of this whale and the absence of severe chronic reaction may suggest that the infestation was not yet at an advanced chronic stage.


1988 ◽  
Vol 66 (2) ◽  
pp. 534-537 ◽  
Author(s):  
Caroline M. Pond ◽  
Christine A. Mattacks

The gross mass, mean adipocyte volume, and hexokinase and phosphofructokinase activities of blubber and internal adipose tissue were measured from fin whales (Balaenoptera physalus) caught in the North Atlantic west of Iceland. Fin whale adipocytes are smaller but more numerous than predictions from allometric equations relating adipose tissue structure to body mass, but the deviations are no greater than those of some terrestrial mammals, including humans. Significant activity of the glycolytic enzymes was measured from all adipose tissue samples except those around the eyeball; the activities of hexokinase and phosphofructokinase measured at room temperature are only slightly lower in the blubber than in the internal adipose depots. There was little evidence for metabolic correlates of the site-specific differences in the structure and chemistry of blubber. The highest capacity for glucose utilization was measured in adipose tissue from depots in the neck and the thorax, both of which may contain thermogenic tissue in neonates.


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