Pulmonary arterial compliance in dogs and pigs: the three-element windkessel model revisited

1999 ◽  
Vol 277 (2) ◽  
pp. H725-H731 ◽  
Author(s):  
Patrick Segers ◽  
Serge Brimioulle ◽  
Nikos Stergiopulos ◽  
Nico Westerhof ◽  
Robert Naeije ◽  
...  
Keyword(s):  
Pulse Pressure ◽  
Arterial Compliance ◽  
Characteristic Impedance ◽  
Consistent Estimate ◽  
Windkessel Model ◽  
Data Regression ◽  
Pulmonary Embolization ◽  
Pulmonary Arterial ◽  
Model C ◽  
Pulse Pressure Method

In six dogs and six weight-matched miniature pigs at baseline and after pulmonary embolization, pulmonary arterial compliance was determined using the pulse pressure method (CPPM), the three-element windkessel model (CWK-3), and the ratio of stroke volume to pulse pressure (SV/PP). CPPM was lower in pigs than in dogs at baseline (0.72 ± 0.23 vs. 1.14 ± 0.29 ml/mmHg, P < 0.05) and after embolism (0.37 ± 0.14 vs. 0.54 ± 0.16 ml/mmHg, P = 0.07) at matched flow, but not at matched flow and pressure. CPPM showed the expected inverse relation with pressure and a direct relation with flow. CWK-3 was closely correlated with CPPM, except for all dogs at baseline where CWK-3 was up to 100% higher than CPPM. Excluding these data, regression analysis yielded CWK-3 = −0.01 + 1.30 ⋅ CPPM( r 2 = 0.97). CWK-3 was found to be unreliable when input impedance first harmonic modulus was close to characteristic impedance, i.e., when reflections were small. SV/PP correlated well with CPPM (SV/PP = −0.10 + 1.76 ⋅ CPPM, r 2 = 0.89). We conclude that 1) CPPM is a consistent estimate of pulmonary arterial compliance in pigs and dogs, 2) CWK-3 and SV/PP overestimate compliance, and 3) CWK-3 is unreliable when wave reflections are small.

Measurement of total pulmonary arterial compliance using invasive pressure monitoring and MR flow quantification during MR-guided cardiac catheterization

2005 ◽  
Vol 289 (3) ◽  
pp. H1301-H1306 ◽  
Author(s):  
Vivek Muthurangu ◽  
David Atkinson ◽  
Maxime Sermesant ◽  
Marc E. Miquel ◽  
Sanjeet Hegde ◽  
...  
Keyword(s):  
Stroke Volume ◽  
Pulse Pressure ◽  
Pulmonary Arterial Pressure ◽  
Arterial Compliance ◽  
Hypertensive Disease ◽  
Pressure Method ◽  
Total Arterial Compliance ◽  
Pulmonary Arterial ◽  
Pulse Pressure Method ◽  
Level Of Agreement

Pulmonary hypertensive disease is assessed by quantification of pulmonary vascular resistance. Pulmonary total arterial compliance is also an indicator of pulmonary hypertensive disease. However, because of difficulties in measuring compliance, it is rarely used. We describe a method of measuring pulmonary arterial compliance utilizing magnetic resonance (MR) flow data and invasive pressure measurements. Seventeen patients with suspected pulmonary hypertension or congenital heart disease requiring preoperative assessment underwent MR-guided cardiac catheterization. Invasive manometry was used to measure pulmonary arterial pressure, and phase-contrast MR was used to measure flow at baseline and at 20 ppm nitric oxide (NO). Total arterial compliance was calculated using the pulse pressure method (parameter optimization of the 2-element windkessel model) and the ratio of stroke volume to pulse pressure. There was good agreement between the two estimates of compliance ( r = 0.98, P < 0.001). However, there was a systematic bias between the ratio of stroke volume to pulse pressure and the pulse pressure method (bias = 61%, upper level of agreement = 84%, lower level of agreement = 38%). In response to 20 ppm NO, there was a statistically significant fall in resistance, systolic pressure, and pulse pressure. In seven patients, total arterial compliance increased >10% in response to 20 ppm NO. As a population, the increase did not reach statistical significance. There was an inverse relation between compliance and resistance ( r = 0.89, P < 0.001) and between compliance and mean pulmonary arterial pressure ( r = 0.72, P < 0.001). We have demonstrated the feasibility of quantifying total arterial compliance using an MR method.

Quantification of right ventricular afterload in patients with and without pulmonary hypertension

2006 ◽  
Vol 291 (4) ◽  
pp. H1731-H1737 ◽  
Author(s):  
Jan-Willem Lankhaar ◽  
Nico Westerhof ◽  
Theo J. C. Faes ◽  
Koen M. J. Marques ◽  
J. Tim Marcus ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Pulmonary Artery ◽  
Right Ventricular ◽  
Pulmonary Artery Pressure ◽  
Arterial Compliance ◽  
Characteristic Impedance ◽  
Peripheral Resistance ◽  
Windkessel Model ◽  
Artery Pressure ◽  
Pulmonary Arterial

Right ventricular (RV) afterload is commonly defined as pulmonary vascular resistance, but this does not reflect the afterload to pulsatile flow. The purpose of this study was to quantify RV afterload more completely in patients with and without pulmonary hypertension (PH) using a three-element windkessel model. The model consists of peripheral resistance ( R), pulmonary arterial compliance ( C), and characteristic impedance ( Z). Using pulmonary artery pressure from right-heart catheterization and pulmonary artery flow from MRI velocity quantification, we estimated the windkessel parameters in patients with chronic thromboembolic PH (CTEPH; n = 10) and idiopathic pulmonary arterial hypertension (IPAH; n = 9). Patients suspected of PH but in whom PH was not found served as controls (NONPH; n = 10). R and Z were significantly lower and C significantly higher in the NONPH group than in both the CTEPH and IPAH groups ( P < 0.001). R and Z were significantly lower in the CTEPH group than in the IPAH group ( P < 0.05). The parameters R and C of all patients obeyed the relationship C = 0.75/ R ( R2 = 0.77), equivalent to a similar RC time in all patients. Mean pulmonary artery pressure P and C fitted well to C = 69.7/P (i.e., similar pressure dependence in all patients). Our results show that differences in RV afterload among groups with different forms of PH can be quantified with a windkessel model. Furthermore, the data suggest that the RC time and the elastic properties of the large pulmonary arteries remain unchanged in PH.

Use of pulse pressure method for estimating total arterial compliance in vivo

1999 ◽  
Vol 276 (2) ◽  
pp. H424-H428 ◽  
Author(s):  
N. Stergiopulos ◽  
P. Segers ◽  
N. Westerhof
Keyword(s):  
Pulse Pressure ◽  
Diastolic Pressure ◽  
Arterial Compliance ◽  
Aortic Pressure ◽  
Lower Limbs ◽  
Pressure Method ◽  
Total Arterial Compliance ◽  
The Difference ◽  
Pulse Pressure Method

We determined total arterial compliance from pressure and flow in the ascending aorta of seven anesthetized dogs using the pulse pressure method (PPM) and the decay time method (DTM). Compliance was determined under control and during occlusion of the aorta at four different locations (iliac, renal, diaphragm, and proximal descending thoracic aorta). Compliance of PPM gave consistently lower values (0.893 ± 0.015) compared with the compliance of DTM (means ± SE; r = 0.989). The lower compliance estimates by the PPM can be attributed to the difference in mean pressures at which compliance is determined (mean pressure, 81.0 ± 3.6 mmHg; mean diastolic pressure, over which the DTM applies, 67.0 ± 3.6 mmHg). Total arterial compliance under control conditions was 0.169 ± 0.007 ml/mmHg. Compliance of the proximal aorta, obtained during occlusion of the proximal descending aorta, was 0.100 ± 0.007 ml/mmHg. Mean aortic pressure was 80.4 ± 3.6 mmHg during control and 102 ± 7.7 mmHg during proximal descending aortic occlusion. From these results and assuming that upper limbs and the head contribute as little as the lower limbs, we conclude that 60% of total arterial compliance resides in the proximal aorta. When we take into account the inverse relationship between pressure and compliance, the contribution of the proximal aorta to the total arterial compliance is even more significant.

Total arterial compliance in dogs: The pulse pressure method versus the area method

1998 ◽  
Vol 31 ◽  
pp. 141
Author(s):  
P. Segers ◽  
P. Verdonck ◽  
Y. Deryck ◽  
S. Brimioulle ◽  
R. Naeije ◽  
...  
Keyword(s):  
Pulse Pressure ◽  
Arterial Compliance ◽  
Area Method ◽  
Pressure Method ◽  
Total Arterial Compliance ◽  
Pulse Pressure Method

Proximal pulmonary arterial obstruction decreases the time constant of the pulmonary circulation and increases right ventricular afterload

2013 ◽  
Vol 114 (11) ◽  
pp. 1586-1592 ◽  
Author(s):  
Alberto Pagnamenta ◽  
Rebecca Vanderpool ◽  
Serge Brimioulle ◽  
Robert Naeije
Keyword(s):  
Pulmonary Hypertension ◽  
Right Ventricular ◽  
Time Constant ◽  
Pulse Pressure ◽  
Pulmonary Circulation ◽  
Characteristic Impedance ◽  
Ventricular Afterload ◽  
Hydraulic Load ◽  
Distal Obstruction ◽  
Pulmonary Arterial

The time constant of the pulmonary circulation, or product of pulmonary vascular resistance (PVR) and compliance (Ca), called the RC-time, has been reported to remain constant over a wide range of pressures, etiologies of pulmonary hypertension, and treatments. We wondered if increased wave reflection on proximal pulmonary vascular obstruction, like in operable chronic thromboembolic pulmonary hypertension, might also decrease the RC-time and thereby increase pulse pressure and right ventricular afterload. Pulmonary hypertension of variable severity was induced either by proximal obstruction (pulmonary arterial ensnarement) or distal obstruction (microembolism) eight anesthetized dogs. Pulmonary arterial pressures (Ppa) were measured with high-fidelity micromanometer-tipped catheters, and pulmonary flow with transonic technology. Pulmonary ensnarement increased mean Ppa, PVR, and characteristic impedance, decreased Ca and the RC-time (from 0.46 ± 0.07 to 0.30 ± 0.03 s), and increased the oscillatory component of hydraulic load (Wosc/Wtot) from 25 ± 2 to 29 ± 2%. Pulmonary microembolism increased mean Ppa and PVR, with no significant change in Ca and characteristic impedance, increased RC-time from 0.53 ± 0.09 to 0.74 ± 0.05 s, and decreased Wosc/Wtot from 26 ± 2 to 13 ± 2%. Pulse pressure increased more after pulmonary ensnarement than after microembolism. Concomitant measurements with fluid-filled catheters showed the same functional differences between the two types of pulmonary hypertension, with, however, an underestimation of Wosc. We conclude that pulmonary hypertension caused by proximal vs. distal obstruction is associated with a decreased RC-time and increased pulsatile component of right ventricular hydraulic load.

Characterization of pulmonary arterial input impedance with lumped parameter models

1987 ◽  
Vol 252 (3) ◽  
pp. H585-H593 ◽  
Author(s):  
B. J. Grant ◽  
L. J. Paradowski
Keyword(s):  
Input Impedance ◽  
Goodness Of Fit ◽  
Arterial Compliance ◽  
Characteristic Impedance ◽  
Lumped Parameter Model ◽  
Pulmonary Vasculature ◽  
Impedance Spectra ◽  
Lumped Parameter ◽  
Lumped Parameter Models ◽  
Pulmonary Arterial

The purpose of this study is to evaluate systematically the ability of lumped parameter models to approximate pulmonary arterial input impedance (Zin) and estimate characteristic impedance (Zc) and pulmonary arterial compliance (Cart). To assess goodness of fit, the parameters of each model were adjusted so that the model's impedance approximates the Zin measured in anesthetized cats. To assess the ability of the model to estimate Zc and Cart, the lumped parameter models were fitted to Zin calculated from a distributed parameter model of the feline pulmonary vasculature. In addition, we assessed the concordance between the lumped parameter model estimates of Zc and Cart. The results indicate that no one model was superior; any of four models would be a reasonable choice. A four-element model was used to compare Zin measured at different phases of the respiratory cycle. Small differences in the impedance spectra were found that have not been previously reported. We conclude that lumped parameter models can be used to provide close approximations to Zin, to estimate Zc and Cart, and to provide a useful approach for statistical comparisons of impedance spectra.

scholarly journals Increasing pulse wave velocity in a realistic cardiovascular model does not increase pulse pressure with age

2012 ◽  
Vol 303 (1) ◽  
pp. H116-H125 ◽  
Author(s):  
Mohammad W. Mohiuddin ◽  
Ryan J. Rihani ◽  
Glen A. Laine ◽  
Christopher M. Quick
Keyword(s):  
Pulse Wave Velocity ◽  
Wave Velocity ◽  
Pulse Pressure ◽  
Pulse Wave ◽  
Arterial Compliance ◽  
Arterial System ◽  
System Model ◽  
Transmission Model ◽  
Windkessel Model ◽  
Reflected Wave

The mechanism of the well-documented increase in aortic pulse pressure (PP) with age is disputed. Investigators assuming a classical windkessel model believe that increases in PP arise from decreases in total arterial compliance ( Ctot) and increases in total peripheral resistance ( Rtot) with age. Investigators assuming a more sophisticated pulse transmission model believe PP rises because increases in pulse wave velocity ( cph) make the reflected pressure wave arrive earlier, augmenting systolic pressure. It has recently been shown, however, that increases in cph do not have a commensurate effect on the timing of the reflected wave. We therefore used a validated, large-scale, human arterial system model that includes realistic pulse wave transmission to determine whether increases in cph cause increased PP with age. First, we made the realistic arterial system model age dependent by altering cardiac output (CO), Rtot, Ctot, and cph to mimic the reported changes in these parameters from age 30 to 70. Then, cph was theoretically maintained constant, while Ctot, Rtot, and CO were altered. The predicted increase in PP with age was similar to the observed increase in PP. In a complementary approach, Ctot, Rtot, and CO were theoretically maintained constant, and cph was increased. The predicted increase in PP was negligible. We found that increases in cph have a limited effect on the timing of the reflected wave but cause the system to degenerate into a windkessel. Changes in PP can therefore be attributed to a decrease in Ctot.

Aortic function quantified: the heart's essential cushion

2012 ◽  
Vol 113 (8) ◽  
pp. 1285-1291 ◽  
Author(s):  
Nabil Saouti ◽  
J. Tim Marcus ◽  
Anton Vonk Noordegraaf ◽  
Nico Westerhof
Keyword(s):  
Pulse Pressure ◽  
Arterial Compliance ◽  
Local Area ◽  
Segment Length ◽  
Coronary Perfusion ◽  
Aortic Blood Flow ◽  
Aortic Compliance ◽  
Pressure Method ◽  
Local Compliance ◽  
Pulse Pressure Method

Arterial compliance is mainly determined by the elasticity of proximal large-conduit arteries of which the aorta is the largest contributor. Compliance forms an important part of the cardiac load and plays a role in organ (especially coronary) perfusion. To follow local changes in aortic compliance, as in aging, noninvasive determination of compliance distribution would be of great value. Our goal is to determine regional aortic compliance noninvasively in the human. In seven healthy individuals at six locations, aortic blood flow and systolic/diastolic area (ΔA) was measured with MRI. Simultaneously brachial pulse pressure (ΔP) was measured with standard cuff. With a transfer function we derived ΔP at the same aortic locations as the MRI measurements. Regional aortic compliance was calculated with two approaches, the pulse pressure method, and local area compliance (ΔA/ΔP) times segment length, called area compliance method. For comparison, pulse wave velocity (PWV) from local flows at two locations was determined, and compliance was derived from PWV. Both approaches show that compliance is largest in the proximal aorta and decreases toward the distal aorta. Similar results were found with PWV-derived compliance. Of total arterial compliance, ascending to distal arch ( segments 1–3) contributes 40% (of which 15% is in head and arms), descending aorta ( segments 4 and 5) 25%, and “hip, pelvic and leg arteries” 20%. Pulse pressure method includes compliance of side branches and is therefore larger than the area compliance method. Regional aortic compliance can be obtained noninvasively. Therefore, this technique allows following changes in local compliance with age and cardiovascular diseases.

P4677Balloon pulmonary angioplasty improves pulmonary arterial compliance in patients with inoperable chronic thromboembolic pulmonary hypertension

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
S Umemoto ◽  
K Abe ◽  
K Horimoto ◽  
K Hosokawa ◽  
H Tsutsui
Keyword(s):  
Pulmonary Hypertension ◽  
Stroke Volume ◽  
Pulse Pressure ◽  
Arterial Compliance ◽  
Chronic Thromboembolic Pulmonary Hypertension ◽  
Heart Catheterization ◽  
Thromboembolic Pulmonary Hypertension ◽  
Pulmonary Arterial ◽  
The Impact

Abstract Background Right ventricular (RV) pressure overload is directly related to the increase in mortality in pulmonary hypertension. Pulmonary arterial compliance (CPA; stroke volume/pulmonary pulse pressure) was reported to be an independent determinant of RV systolic afterload in patients with pulmonary arterial hypertension (PAH). Recently, balloon pulmonary angioplasty (BPA) has been reported to reduce mean pulmonary artery pressure (mPAP) and pulmonary vascular resistance (RPA) in patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH). However, the effects of BPA on CPA remain unclear. Purpose The aim of this study was to investigate the impact of BPA on CPA in patients with inoperable CTEPH. Methods We retrospectively analyzed 78 patients (388 BPA sessions) with inoperable CTEPH who underwent BPA in our hospital from September 2012 to June 2018. Total number of BPA sessions was 5.0±1.8 (range 1–10). The pressure values were obtained from right heart catheterization at baseline (n=78), just after the final BPA (n=78) and follow-up (n=19) periods. The intervals from baseline to the final BPA and the final BPA to follow-up were 593±498 days and 397±276 days, respectively. Results Mean age was 60.5±12.6 years old, and 64 (82%) were female. All patients were symptomatic (WHO functional class II/III/IV 16/55/7). Patients who had pulmonary vasodilators decreased from 70 (90%) at baseline to 23 (28%) at the final BPA and 2 (15%) at follow-up. BPA reduced mPAP and RPA significantly from baseline to the final BPA and follow-up periods. BPA also improved CPA with significant reduction of pulse pressure despite no significant changes in stroke volume between baseline and follow-up (Table). CPA between the final BPA and follow-up was equivalent (p=0.95). Conclusions BPA improved CPA just after the final BPA in inoperable CTEPH patients. In addition, CPA was preserved during the follow-up after the final BPA sessions. These data suggest that BPA consistently unloads RV systolic afterload in those patients.

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