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

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.

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
S Umemoto ◽  
K Abe ◽  
K Horimoto ◽  
K Hosokawa ◽  
H Tsutsui

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.


2021 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
H Hayama ◽  
T Uejima ◽  
T Okazaki ◽  
H Hara ◽  
Y Hiroi

Abstract Funding Acknowledgements Type of funding sources: Public hospital(s). Main funding source(s): International Medical Research and Development Fund Background Measuring pulmonary vascular resistance (PVR) is essential for diagnosing pulmonary hypertension. PVR can be estimated from a simple ratio of tricuspid regurgitation velocity (TRV) to time-velocity integral of flow through right ventricular outflow tract (RVOT) (Abbas equation), but this relationship has been shown to be unreliable in patients with high PVR. Once PVR is elevated, there is an increased pressure wave reflected from the peripheral of pulmonary artery (PA). We tested the hypothesis that assessing PA wave reflection could be an alternative method for estimating PVR. Methods This study recruited 83 patients (69 ± 14 years old, 44 men), including 41 patients with left-sided heart disease, 23 patients with pulmonary arterial hypertension and 19 patients with chronic thromboembolic pulmonary hypertension. PA wave reflection was assessed by separating PA pressure waveform derived from a Doppler tracing of TRV into forward and backward pressure (Pf and Pb), using a velocity profile at RVOT. This separation was based on the concept of wave intensity. PVR was estimated using Abbas equation. Pb and PVR by Abbas equation were compared for the correlations with direct measurement of PVR by right heart catheterisation within 48 hours after echocardiography. Results Figure A illustrates Pb and Pf waveforms obtained from a patient with chronic thromboembolic pulmonary hypertension. Pb increased from mid systole and formed a late peak of PA pressure waveform. Pb correlated strongly with PVR by catheter (figure B), whereas PVR by Abbas equation underestimated PVR especially when PVR was high, resulting in a moderate correlation (figure C). Receiver-operator characteristic curves showed a higher accuracy of Pb for identifying PVR &gt; 3WU as well as 6WU, compared with PVR by Abbas equation (figure D and E). Conclusions This novel echocardiographic method for assessing PA wave reflection helps diagnose the severity of pulmonary hypertension. Abstract Figure.


2020 ◽  
Vol 10 (4) ◽  
pp. 204589402096383
Author(s):  
Thenappan Thenappan ◽  
Nadine Al-Naamani ◽  
Stefano Ghio ◽  
Hossein-Ardeschir Ghofrani ◽  
Paul M. Hassoun ◽  
...  

Pulmonary arterial compliance is a measure of the pulsatile afterload of the right ventricle. Lower pulmonary arterial compliance is associated with reduced right ventricular function and worse prognosis in pulmonary hypertension. The effect of pulmonary vasodilators on pulmonary arterial compliance has not been evaluated in detail in pulmonary arterial hypertension or chronic thromboembolic pulmonary hypertension. In this post hoc analysis of patients with pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension in the PATENT and CHEST studies, we evaluated the change in pulmonary arterial compliance with riociguat versus placebo. Association of pulmonary arterial compliance with clinical outcomes was assessed using Kaplan–Meier and Cox proportional hazards analyses. Compared with placebo, riociguat significantly improved pulmonary arterial compliance in patients with pulmonary arterial hypertension or chronic thromboembolic pulmonary hypertension. Pulmonary arterial compliance at baseline was associated with survival and clinical worsening-free survival in pulmonary arterial hypertension but only with clinical worsening-free survival in chronic thromboembolic pulmonary hypertension. In patients with pulmonary arterial hypertension, pulmonary arterial compliance at follow-up ≥1.6 mL/mmHg was associated with better outcomes than pulmonary arterial compliance <1.6 mL/mmHg. In patients with chronic thromboembolic pulmonary hypertension, pulmonary arterial compliance at follow-up did not predict outcomes. Cox proportional hazards analyses showed no association between change in pulmonary arterial compliance and outcomes in patients with pulmonary arterial hypertension or chronic thromboembolic pulmonary hypertension. In conclusion, riociguat improved pulmonary arterial compliance in patients with pulmonary arterial hypertension or chronic thromboembolic pulmonary hypertension. Pulmonary arterial compliance at baseline or follow-up, rather than change in pulmonary arterial compliance, is of prognostic importance for outcomes.


Respiration ◽  
2021 ◽  
pp. 1-10
Author(s):  
Christian Nagel ◽  
Nicola Benjamin ◽  
Benjamin Egenlauf ◽  
Christina A. Eichstaedt ◽  
Christine Fischer ◽  
...  

<b><i>Background:</i></b> Pulmonary arterial compliance (PAC) is a prognostic parameter in pulmonary arterial hypertension (PAH) reflecting the elasticity of the pulmonary vessels. <b><i>Objectives:</i></b> The objective of this post hoc analysis of a prospective randomized controlled trial (RCT) was to assess the effect of exercise training on PAC and stroke volume (SV) in patients with PAH and persistent/inoperable chronic thromboembolic pulmonary hypertension (CTEPH). <b><i>Method:</i></b> From the previous RCT, 43 out of 87 patients with severe PAH (<i>n</i> = 29) and CTEPH (<i>n</i> = 14) had complete haemodynamic examinations at baseline and after 15 weeks by right heart catheterization and were analysed (53% female, 79% World Health Organization functional class III/IV, 58% combination therapy, 42% on supplemental oxygen therapy, training group <i>n</i> = 24, and control group <i>n</i> = 19). Medication remained unchanged for all patients. <b><i>Results:</i></b> Low-dose exercise training at 4–7 days/week significantly improved PAC (training group 0.33 ± 0.65 mL/mm Hg vs. control group −0.06 ± 1.10 mL/mm Hg; mean difference 0.39 mL/mm Hg, 95% confidence interval [CI] 0.15–0.94 mL/mm Hg; <i>p</i> = 0.004) and SV (training group 9.9 ± 13.4 mL/min vs. control group −4.2 ± 11.0 mL/min; mean difference 14.2 mL, 95% CI 6.5–21.8 mL; <i>p</i> &#x3c; 0.001) in the training versus control group. Furthermore, exercise training significantly improved cardiac output and pulmonary vascular resistance at rest, peak oxygen consumption, and oxygen pulse. <b><i>Conclusions:</i></b> Our findings suggest that supervised exercise training may improve right ventricular function and PAC at the same time. Further prospective studies are needed to evaluate these findings.


2021 ◽  
pp. 204589402110407
Author(s):  
Andrew J Sweatt ◽  
Raju Reddy ◽  
Farbod Rahaghi ◽  
Nadine Al-Naamani

In this conference paper, we review the 2020 American Thoracic Society (ATS) International Conference session titled, “What’s New in Pulmonary Hypertension Clinical Research: Lessons from the Best Abstracts”. This virtual mini-symposium took place on October 21, 2020, in lieu of the annual in-person ATS International Conference which was cancelled due to the COVID-19 pandemic. Seven clinical research abstracts were selected for presentation in the session, which encompassed five major themes: (1) standardizing diagnosis and management of pulmonary hypertension, (2) improving risk assessment in pulmonary arterial hypertension, (3) evaluating biomarkers of disease activity, (4) understanding metabolic dysregulation across the spectrum of pulmonary hypertension, and (5) advancing knowledge in chronic thromboembolic pulmonary hypertension. Focusing on these five thematic contexts we review the current state of knowledge, summarize presented research abstracts, appraise their significance and limitations, and then discuss relevant future directions in pulmonary hypertension clinical research.


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