Electrical Impedance Tomography for Assessment of Pulmonary Hypertension

Official title

Assessment of Pulmonary Artery Pressure and Hemodynamic Measurements by Electrical Impedance Tomography and Right Heart Catheterization

Overview

Pulmonary hypertension is a serious and progressive disease that is difficult to treat and diagnose, mainly because its symptoms are nonspecific and often delay recognition. Early diagnosis is a major challenge. Although several tests may suggest the disease, the definitive diagnosis still requires right heart catheterization, an invasive procedure that directly measures pulmonary hemodynamics such as pulmonary artery pressure, cardiac output, and vascular resistance. Electrical impedance tomography (EIT) is a non-invasive, radiation-free bedside monitoring method that can evaluate ventilation and pulmonary perfusion. The number of studies investigating perfusion with EIT has been increasing, since the possibility of having a safe, radiation-free, and repeatable method available at the bedside is of great clinical interest in different fields of medicine. Our hypothesis is that EIT provides information that correlates with the findings of right heart catheterization in patients with suspected pulmonary arterial hypertension (PAH). EIT may serve as a useful screening tool prior to catheterization and may also help in risk stratification of patients with pulmonary hypertension

Detailed description

This single-center, prospective diagnostic study is designed to investigate whether EIT-derived measures correlate with invasive hemodynamic parameters obtained by RHC. Adult patients referred for RHC due to suspected PAH or for disease staging will undergo standard catheterization, followed by short-term EIT monitoring. Some patients will additionally receive a hypertonic saline injection during a respiratory pause to enhance the perfusion signal. All EIT data will be processed offline using dedicated algorithms to separate ventilation and perfusion signals and to extract pulsatility-related parameters (e.g., amplitude, area, inflection points). These values will then be compared with RHC-derived hemodynamic measures such as mean pulmonary artery pressure (mPAP), pulmonary vascular resistance (PVR), cardiac output (CO), and stroke volume (SV).

The primary outcome of this study is to determine the diagnostic accuracy of EIT for detecting pulmonary hypertension, aiming at high sensitivity and clinical utility as a screening tool prior to invasive catheterization. Secondary analyses will include exploration of additional EIT-derived perfusion and pulsatility indices, assessment of diagnostic thresholds for different levels of PAH severity, and evaluation of prognostic implications.

Risks associated with participation are minimal, as EIT is non-invasive and safe. The risks of RHC are those inherent to the procedure and are independent of the study. While no direct benefit is expected for individual participants, the findings may provide important insights into the use of EIT as a less invasive diagnostic strategy for PAH, with potential implications for clinical practice and patient care.

Interventions

• Diagnostic test Electrical Impedance Tomography (EIT)
  Non-invasive, radiation-free bedside monitoring of ventilation and pulmonary perfusion. Patients will be monitored for a short period using EIT, with data analyzed offline to assess pulsatility and perfusion indices.
• Procedure Right Heart Catheterization
  Standard invasive hemodynamic assessment performed for clinical indication, including measurement of pulmonary artery pressure, cardiac output, pulmonary vascular resistance, and stroke volume. Used as the gold standard comparator for EIT-derived measures.

Primary outcome measures

• Sensitivity (%) of Electrical Impedance Tomography (EIT)-Derived Pulsatility Amplitude for Detection of Pulmonary Hypertension Defined by Mean Pulmonary Artery Pressure [Time frame: At the time of right heart catheterization (baseline, single assessment)]

Secondary outcome measures (6)

• Pearson or Spearman Correlation Coefficient (r) Between EIT-Derived Pulsatility Amplitude (ΔZ) and Mean Pulmonary Artery Pressure (mmHg) [Time frame: At the time of right heart catheterization]
• Correlation Coefficient (r) Between EIT Pulsatility Amplitude and Fractional Area Change (%) [Time frame: Immediately after right heart catheterization (single assessment at baseline)]
• Correlation Coefficient (r) Between EIT Pulsatility Amplitude (ΔZ) and Tricuspid Annular Plane Systolic Excursion (mm) [Time frame: Immediately after right heart catheterization (single assessment at baseline)]
• Correlation Coefficient (r) Between EIT Pulsatility Amplitude and Tissue Doppler Systolic Velocity (cm/s) [Time frame: immediately after right heart catheterization]
• Sensitivity (%), Specificity (%), and Area Under the ROC Curve (AUC) of EIT Pulsatility Amplitude for Detection of Pulmonary Hypertension at Different mPAP Thresholds [Time frame: At the time of Right Heart Catheterization.]
• Area Under the ROC Curve (AUC) of EIT Pulsatility Amplitude for Classification of Pulmonary Hypertension Severity [Time frame: At the time of right heart catheterization]

Eligibility criteria

Inclusion criteria

• Patients with a diagnosis or clinical suspicion of pulmonary arterial hypertension (PAH) and with a medical indication for right heart catheterization.
• Patients evaluated at the Pulmonology Service of InCor-HCFMUSP.

Exclusion criteria

• Pregnancy.
• Structural heart disease, such as atrial septal defect, ventricular septal defect, or valvular disease.
• Cardiac arrhythmias.
• Presence of a cardiac pacemaker or other implantable electronic device.
• Skin lesions at the thoracic region that would prevent placement of the EIT electrode belt.
• WHO functional class IV of new york heart association (NYAH)..
• Inability to perform a voluntary respiratory pause (apnea) of at least 30 seconds or inability to understand and follow instructions required.
• Decline to participate in the study by not signing the informed consent form or refusal by the attending medical team.

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

N/A

Model

Single group

Masking

Open label

Primary purpose

Diagnostic

Study locations

Brazil · 1 center

• Instituto do Coração do Hospital das Clínicas da Faculdade de Medicina da USP — São Paulo

Publications

• Adler A, Arnold JH, Bayford R, Borsic A, Brown B, Dixon P, Faes TJ, Frerichs I, Gagnon H, Garber Y, Grychtol B, Hahn G, Lionheart WR, Malik A, Patterson RP, Stocks J, Tizzard A, Weiler N, Wolf GK. GREIT: a unified approach to 2D linear EIT reconstruction of lung images. Physiol Meas. 2009 Jun;30(6):S35-55. doi: 10.1088/0967-3334/30/6/S03. Epub 2009 Jun 2. PMID 19491438
• Barber DC, Brown BH. Applied potential tomography. J Br Interplanet Soc. 1989 Aug;42(7):391-3. PMID 11540235
• Eyuboglu BM, Brown BH, Barber DC, Seagar AD. Localisation of cardiac related impedance changes in the thorax. Clin Phys Physiol Meas. 1987;8 Suppl A:167-73. doi: 10.1088/0143-0815/8/4a/021. PMID 3568566
• Fagerberg A, Stenqvist O, Aneman A. Monitoring pulmonary perfusion by electrical impedance tomography: an evaluation in a pig model. Acta Anaesthesiol Scand. 2009 Feb;53(2):152-8. doi: 10.1111/j.1399-6576.2008.01847.x. PMID 19175575
• Guerin L, Couturaud F, Parent F, Revel MP, Gillaizeau F, Planquette B, Pontal D, Guegan M, Simonneau G, Meyer G, Sanchez O. Prevalence of chronic thromboembolic pulmonary hypertension after acute pulmonary embolism. Prevalence of CTEPH after pulmonary embolism. Thromb Haemost. 2014 Sep 2;112(3):598-605. doi: 10.1160/TH13-07-0538. Epub 2014 Jun 5. PMID 24898545
• Jenkins DP, Madani M, Mayer E, Kerr K, Kim N, Klepetko W, Morsolini M, Dartevelle P. Surgical treatment of chronic thromboembolic pulmonary hypertension. Eur Respir J. 2013 Mar;41(3):735-42. doi: 10.1183/09031936.00058112. Epub 2012 Nov 8. PMID 23143539
• Konstantinides SV, Meyer G, Becattini C, Bueno H, Geersing GJ, Harjola VP, Huisman MV, Humbert M, Jennings CS, Jimenez D, Kucher N, Lang IM, Lankeit M, Lorusso R, Mazzolai L, Meneveau N, Ni Ainle F, Prandoni P, Pruszczyk P, Righini M, Torbicki A, Van Belle E, Zamorano JL; ESC Scientific Document Group. 2019 ESC Guidelines for the diagnosis and management of acute pulmonary embolism developed in co PMID 31504429
• Lang IM, Pesavento R, Bonderman D, Yuan JX. Risk factors and basic mechanisms of chronic thromboembolic pulmonary hypertension: a current understanding. Eur Respir J. 2013 Feb;41(2):462-8. doi: 10.1183/09031936.00049312. Epub 2012 Jun 14. PMID 22700839

Identifiers

NCT: NCT07453017 · 76762824.6.0000.0068

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗