Self-Similarities of Pulmonary Arterial Tree and a New Integrated Model of Pulmonary Circulation with the Name of Fractal Phasic Perfusion (FPP) Model

2020 ◽  
Author(s):  
Kyongyob Min
Keyword(s):  
Pulmonary Circulation ◽  
Integrated Model ◽  
Arterial Tree ◽  
Pulmonary Arterial

scholarly journals Decreased time constant of the pulmonary circulation in chronic thromboembolic pulmonary hypertension

2013 ◽  
Vol 305 (2) ◽  
pp. H259-H264 ◽  
Author(s):  
Robert V. MacKenzie Ross ◽  
Mark R. Toshner ◽  
Elaine Soon ◽  
Robert Naeije ◽  
Joanna Pepke-Zaba
Keyword(s):  
Pulmonary Hypertension ◽  
Time Constant ◽  
Pulmonary Circulation ◽  
Wave Reflection ◽  
Arterial Compliance ◽  
Chronic Thromboembolic Pulmonary Hypertension ◽  
Left Heart Failure ◽  
Thromboembolic Pulmonary Hypertension ◽  
Pulmonary Arterial ◽  
Rc Time Constant

This study analyzed the relationship between pulmonary vascular resistance (PVR) and pulmonary arterial compliance ( Ca) in patients with idiopathic pulmonary arterial hypertension (IPAH) and proximal chronic thromboembolic pulmonary hypertension (CTEPH). It has recently been shown that the time constant of the pulmonary circulation (RC time constant), or PVR × Ca, remains unaltered in various forms and severities of pulmonary hypertension, with the exception of left heart failure. We reasoned that increased wave reflection in proximal CTEPH would be another cause of the decreased RC time constant. We conducted a retrospective analysis of invasive pulmonary hemodynamic measurements in IPAH ( n = 78), proximal CTEPH ( n = 91) before (pre) and after (post) pulmonary endarterectomy (PEA), and distal CTEPH ( n = 53). Proximal CTEPH was defined by a postoperative mean pulmonary artery pressure (PAP) of ≤25 mmHg. Outcome measures were the RC time constant, PVR, Ca, and relationship between systolic and mean PAPs. The RC time constant for pre-PEA CTEPH was 0.49 ± 0.11 s compared with post-PEA-CTEPH (0.37 ± 0.11 s, P < 0.0001), IPAH (0.63 ± 0.14 s, P < 0.001), and distal CTEPH (0.55 ± 0.12 s, P < 0.05). A shorter RC time constant was associated with a disproportionate decrease in systolic PAP with respect to mean PAP. We concluded that the pulmonary RC time constant is decreased in proximal CTEPH compared with IPAH, pre- and post-PEA, which may be explained by increased wave reflection but also, importantly, by persistent structural changes after the removal of proximal obstructions. A reduced RC time constant in CTEPH is in accord with a wider pulse pressure and hence greater right ventricular work for a given mean PAP.

Characteristics of the pulmonary circulation in infants with complete atrioventricular septal defect

2020 ◽  
pp. 1-6
Author(s):  
Hirohito Doi ◽  
Jun Muneuchi ◽  
Mamie Watanabe ◽  
Yuichiro Sugitani ◽  
Ryohei Matsuoka ◽  
...  
Keyword(s):  
Down Syndrome ◽  
Gestational Age ◽  
Pulmonary Circulation ◽  
Septal Defect ◽  
Atrioventricular Septal Defect ◽  
Left Heart ◽  
Complete Atrioventricular Septal Defect ◽  
Pulmonary Arterial ◽  
Heart Lesions ◽  
Complete Atrioventricular

Abstract Objective: Infants with complete atrioventricular septal defect occasionally accompany pulmonary hypertension; however, the pulmonary circulation can be altered by pulmonary vascular conditions as well as the left heart lesions. This study aimed to explore whether the left heart lesions were related to the pulmonary circulation among them. Methods: We performed echocardiography and cardiac catheterisation in 42 infants with complete atrioventricular septal defect and studied relationships between the pulmonary haemodynamic parameters and the left heart morphology. Results: Age and weight at preoperative evaluation were 65 days (47-114) (the median following interquartile range) and 5.5 kg (4.0-7.1), respectively. There were 27 individuals with Down syndrome. Gestational age was 38 weeks (37-39). Catheterisation showed mean pulmonary arterial pressure: 36 (29-46) mmHg, the ratio of pulmonary to systemic blood flow: 3.45 (2.79-4.98), pulmonary vascular resistance: 2.20 Wood units·m2 (1.53-3.65), and pulmonary arterial compliance: 2.78 (1.86-4.10) ml/Hg/m2. Echocardiography showed the Rastelli classification type A in 28 and type C in 14, moderate or severe left atrioventricular valve regurgitation in 19 patients (45%), atrioventricular valve index of 0.67 (0.56-0.79), left ventricular end-diastolic volume z score of 4.46 (1.96-7.78), and aortic valve diameter z score of −0.70 (−1.91 to 0.20). Multivariable regression analysis revealed that preoperative pulmonary vascular resistance was significantly correlated to gestational age (p = 0.002), and that preoperative pulmonary arterial compliance was significantly correlated to gestational age (p = 0.009) and Down syndrome (p = 0.036). Conclusions: The pulmonary circulation does not depend upon the presence of left heart lesions but gestational age and Down syndrome in infants with complete atrioventricular septal defect.

Histamine-induced pulmonary edema distal to pulmonary arterial occlusion

1985 ◽  
Vol 58 (4) ◽  
pp. 1092-1098 ◽  
Author(s):  
M. D. Walkenstein ◽  
B. T. Peterson ◽  
J. E. Gerber ◽  
R. W. Hyde
Keyword(s):  
Pulmonary Edema ◽  
Pulmonary Circulation ◽  
Arterial Occlusion ◽  
Arterial Blood Flow ◽  
Water Volume ◽  
Lung Water ◽  
Arterial Blood ◽  
Perfused Lung ◽  
Pulmonary Arterial ◽  
The Right

Histological studies provide evidence that the bronchial veins are a site of leakage in histamine-induced pulmonary edema, but the physiological importance of this finding is not known. To determine if a lung perfused by only the bronchial arteries could develop pulmonary edema, we infused histamine for 2 h in anesthetized sheep with no pulmonary arterial blood flow to the right lung. In control sheep the postmortem extravascular lung water volume (EVLW) in both the right (occluded) and left (perfused) lung was 3.7 +/- 0.4 ml X g dry lung wt-1. Following histamine infusion, EVLW increased to 4.4 +/- 0.7 ml X g dry lung wt-1 in the right (occluded) lung (P less than 0.01) and to 5.3 +/- 1.0 ml X g dry wt-1 in the left (perfused) lung (P less than 0.01). Biopsies from the right (occluded) lungs scored for the presence of edema showed a significantly higher score in the lungs that received histamine (P less than 0.02). Some leakage from the pulmonary circulation of the right lung, perfused via anastomoses from the bronchial circulation, cannot be excluded but should be modest considering the low pressures in the pulmonary circulation following occlusion of the right pulmonary artery. These data show that perfusion via the pulmonary arteries is not a requirement for the production of histamine-induced pulmonary edema.

Three-dimensional CT angiography of anatomic variations in the pulmonary arterial tree

2017 ◽  
Vol 40 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Alex Fourdrain ◽  
Florence De Dominicis ◽  
Chloé Blanchard ◽  
Jules Iquille ◽  
Sophie Lafitte ◽  
...  
Keyword(s):  
Ct Angiography ◽  
Three Dimensional ◽  
Anatomic Variations ◽  
Arterial Tree ◽  
Pulmonary Arterial

PULMONARY VASCULAR ADJUSTMENTS IN THE NEONATAL PERIOD

PEDIATRICS ◽  
1961 ◽  
Vol 28 (1) ◽  
pp. 28-34 ◽  
Author(s):  
Abraham M. Rudolph ◽  
Peter A. M. Auld ◽  
Richard J. Golinko ◽  
Milton H. Paul
Keyword(s):  
Arterial Pressure ◽  
Pulmonary Circulation ◽  
Neonatal Period ◽  
Pulmonary Arterial Pressure ◽  
Systolic Pressure ◽  
Indwelling Catheters ◽  
Pulmonary Vessels ◽  
Pulmonary Arterial ◽  
Unanesthetized Animals ◽  
Young Puppy

Pulmonary arterial or right ventricular pressures were measured repeatedly in 18 puppies and 2 goats, from 1 to 36 days of age; these pressures were measured with the use of indwelling catheters in unanesthetized animals. In puppies the systolic pressure in the pulmonary circulation decreased rapidly to near adult levels in 5 to 10 days after birth, and then more slowly to adult levels by 5 to 6 weeks of age. In goats the pressures decreased more slowly, reaching near adult levels in about 12 to 14 days. Acetylcholine produced a decrease in pulmonary arterial pressure in the puppy in the first 5 days of life, but an increase in pulmonary pressure after that time in the resting animal. In the hypoxic puppy, a reduction in pulmonary arterial pressure was induced by acetylcholine. These findings suggest that the pulmonary vessels in the young puppy are actively constricted but that relaxation occurs after the first few days of life.

Impact of parallel heterogeneity on a continuum model of the pulmonary arterial tree

1994 ◽  
Vol 77 (2) ◽  
pp. 660-670 ◽  
Author(s):  
G. S. Krenz ◽  
J. Lin ◽  
C. A. Dawson ◽  
J. H. Linehan
Keyword(s):  
Continuum Model ◽  
Vessel Diameter ◽  
Arterial Tree ◽  
Vascular Volume ◽  
Homogeneous Trees ◽  
Number Ratio ◽  
Pulmonary Arterial ◽  
Beta 2 ◽  
Ordered Tree ◽  
Intravascular Pressure

Model arterial trees were constructed following rules consistent with morphometric data, Nj = (Dj/Da)-beta 1 and Lj = La(Dj/Da)beta 2, where Nj, Dj, and Lj are number, diameter, and length, respectively, of vessels in the jth level; Da and La are diameter and length, respectively, of the inlet artery, and -beta 1 and beta 2 are power law slopes relating vessel number and length, respectively, to vessel diameter. Simulated heterogeneous trees approximating these rules were constructed by assigning vessel diameters Dm = Da[2/(m + 1)]1/beta 1, such that m-1 vessels were larger than Dm (vessel length proportional to diameter). Vessels were connected, forming random bifurcating trees. Longitudinal intravascular pressure [P(Qcum)] with respect to cumulative vascular volume [Qcum] was computed for Poiseuille flow. Strahler-ordered tree morphometry yielded estimates of La, Da, beta 1, beta 2, and mean number ratio (B); B is defined by Nk + 1 = Bk, where k is total number of Strahler orders minus Strahler order number. The parameters were used in P(Qcum) = Pa [formula: see text] and the resulting P(Qcum) relationship was compared with that of the simulated tree, where Pa is total arterial pressure drop, Q is flow rate, Ra = (128 microLa)/(pi D4a (where mu is blood viscosity), and Qa (volume of inlet artery) = 1/4D2a pi La. Results indicate that the equation, originally developed for homogeneous trees (J. Appl. Physiol. 72: 2225–2237, 1992), provides a good approximation to the heterogeneous tree P(Qcum).

Effect of surface tension on circulation in the excised lungs of dogs

1964 ◽  
Vol 19 (4) ◽  
pp. 707-712 ◽  
Author(s):  
I. Bruderman ◽  
K. Somers ◽  
W. K. Hamilton ◽  
W. H. Tooley ◽  
J. Butler
Keyword(s):  
Surface Tension ◽  
Arterial Pressure ◽  
Pulmonary Vascular Resistance ◽  
Lung Volume ◽  
Pulmonary Circulation ◽  
Pulmonary Arterial Pressure ◽  
Alveolar Pressure ◽  
Pulmonary Arterial ◽  
Air Liquid Interface ◽  
Effect Of Surface

The hypothesis that the surface tension of the fluid film which lines the lung alveoli reduces the pericapillary pressure in air-filled lungs was tested by perfusing the excised lungs of dogs with saline, 6% dextran in saline, and blood. After almost maximal inflation with air from low volumes or the degassed state (inflation state) the pulmonary arterial pressure, relative to the base of the lungs, was lower than the alveolar pressure with flows up to 50 ml/min. It was higher than the alveolar pressure at any flow when the air-liquid interface had been abolished by filling the lungs to the same volume with fluid. The pulmonary arterial pressure at the same flow and alveolar pressure was lower in the inflation state than after deflation from higher volumes (the deflation state). However, lung volume was larger in the deflation state. The possibility of some low resistance channels in the inflation state could not be excluded. However, histological examinations showed that the alveolar capillaries were patent and failed to show any airless lung. pulmonary circulation; pericapillary pressure in lungs; surface tension and pulmonary vascular resistance Submitted on July 29, 1963

Sign in / Sign up

Export Citation Format

Share Document