Status and Future Directions for Balloon Pulmonary Angioplasty in Chronic Thromboembolic Pulmonary Disease With and Without Pulmonary Hypertension

Authors, Journal, Affiliations, Type, DOI

• Authors: Vikas Aggarwal, Jay Giri, Scott H. Visovatti, Ehtisham Mahmud, Hiromi Matsubara, Michael Madani, Frances Rogers, Deepa Gopalan, Kenneth Rosenfield, Vallerie V. McLaughlin; on behalf of the AHA Council on Clinical Cardiology and multiple co-councils
• Journal: Circulation. 2024;149:e1090–e1107
• Affiliations: Henry Ford Health System; University of Pennsylvania; The Ohio State University; UC San Diego; National Hospital Organization Okayama Medical Center (Japan); University of Michigan; Temple University; Massachusetts General Hospital; Hammersmith Hospital Imperial College (UK)
• Type: AHA Scientific Statement (Consensus)
• DOI: https://doi.org/10.1161/CIR.0000000000001197

Overview

This AHA Scientific Statement is the first comprehensive expert consensus document dedicated to balloon pulmonary angioplasty (BPA) for chronic thromboembolic pulmonary disease (CTEPD) with and without pulmonary hypertension. It addresses critical gaps in clinical practice: personnel requirements, patient selection criteria, pre-procedural planning, procedural performance standards, and post-procedural follow-up. The statement validates BPA's newly upgraded ESC 2022 Class I recommendation for inoperable and residual CTEPH, supported by two landmark RCTs (RACE and MR BPA). It provides the first systematic lesion classification and anatomical framework for BPA, outlines safety trends showing halved complication rates from 2013–2017 to 2018–2022, and defines criteria for expert CTEPH centre designation.

Keywords

AHA Scientific Statements, angioplasty balloon, endarterectomy, hypertension pulmonary, pulmonary embolism, thromboembolism

Key Takeaways

Background and Disease Context

• CTEPD with PH (CTEPH) is the most feared long-term complication of acute PE, occurring in ~2–3% of all acute PEs. It results from incomplete clot resolution with fibrotic transformation of residual thrombi in the pulmonary vasculature.
• Pulmonary endarterectomy (PEA) remains the treatment of choice for technically operable patients with surgically accessible disease, performed under deep hypothermic circulatory arrest.
• BPA has emerged as a percutaneous revascularisation option for patients unsuitable for PEA or with residual obstruction after PEA; it has been performed since the 1990s but is undergoing rapid global dissemination.
• ESC 2022 guidelines give BPA a Class I recommendation for inoperable and residual CTEPH — a major upgrade — supported by RACE and MR BPA trials showing BPA superior to riociguat in reducing PVR for inoperable distal CTEPH with PVR >4 Wood units.

Anatomical Considerations

• The pulmonary arterial tree divides into 10 segmental zones per lung. Right lung: superior trunk (truncus anterior) + inferior trunk (interlobar artery). Left lung: shorter main PA divides into interlobar trunk only.
• Key left-sided anatomical caveats: left A1+2 often supplied as common artery; left A4+A5 supply the lingula (not a true middle lobe); left A7 is diminutive and often subsegmental.
• Nonselective invasive pulmonary angiography (NS-iPA) is subject to interobserver variability for disease-level assessment. CTPA is excellent for main/lobar/segmental disease but has lower accuracy for subsegmental disease.

Anatomical Disease Level Classification (Key for Treatment Selection)

• Level 1: Main pulmonary artery disease — surgically accessible
• Level 2: Lobar disease — surgically accessible
• Level 3: Segmental disease — surgically accessible (in most expert centres)
• Level 4: Subsegmental disease — typically managed with BPA (Class I recommendation per ESC 2022)
• Isolated level 4 disease is best managed with BPA; isolated level 3 mid-to-distal segmental disease is a zone of expert disagreement.

NS-iPA Best Practices

• Two angiographic runs per lung in orthogonal projections during deep inspiratory breath holds with digital subtraction.
• Two projection options: (1) frontal + lateral (LAO 0 + LAO/RAO 70–90); (2) ipsilateral oblique + contralateral oblique (RAO 20–45 / LAO 20–45).
• Frontal/lateral projections reduce perfusion zone overlap but increase radiation dose; oblique projections preferred as BPA road maps due to lower radiation.
• Biplane angiography reduces total contrast and radiation dose when available.

Patient Selection

• Multidisciplinary team approach is the core principle: Must include expertise in diagnostic imaging, PEA, BPA, and CTEPH medical management. Missing one core area can bias recommendations toward local availability rather than optimal patient care.
• PEA preferred over BPA for patients with proximal (level 1–3) accessible disease, few comorbidities, and haemodynamics proportionate to observable obstruction.
• BPA preferred for: (1) inoperable patients (level 4 or distal disease); (2) residual CTEPH after PEA; (3) high surgical risk due to comorbidities; (4) patients who decline surgery.
• Riociguat pretreatment before BPA is supported by RACE trial data; BPA without riociguat is possible but requires shared decision-making about risks.
• CTEPD without resting PH: Exercise RHC and invasive CPET can phenotype dyspnoea causes; PEA and BPA have been shown to improve symptoms and ventilatory efficiency in this population, but data remain limited.
• Mild CTEPH (mPAP >20 mmHg, PVR >2 WU): Asymptomatic patients likely do not require intervention; symptomatic patients may derive benefit from BPA/PEA, but pulmonary vasodilator therapy and close follow-up can yield acceptable outcomes.
• CKD: BPA is safe in CKD; limit contrast to ≤3× baseline GFR.

Expert CTEPH Centre Requirements

• Annual BPA volume ≥30 patients or >100 BPA procedures; PEA volume >50/year (ESC/ERS criteria for expert centre designation).
• Expert CTEPH centre must offer both PEA and BPA — BPA programs should be initiated only within experienced CTEPH centres offering PEA.
• Referring centres are responsible for: V/Q screening, echo surveillance, RHC, acute PE management, anticoagulation, venous health.
• Expert PH centres additionally provide: PH physician expertise, advanced echo for RV assessment, CTPA expertise, CPET, catheter/surgical embolectomy.
• Expert CTEPH centres additionally require: PEA surgeon, BPA interventionalist, nuclear medicine, invasive PA angiography expertise, ECMO on-site, lung transplant access.

BPA Lesion Classification (Kawakami et al.)

• Type 1: Ring lesions — standard risk
• Type 2: Web lesions — standard risk
• Type 3: Subtotal occlusions — higher risk
• Type 4: Total occlusions — higher risk
• Type 5: Diffusely tortuous vessels distal to subsegmental branches — highest risk; vascular complications >40%; BPA should be avoided in this subtype
• Complication risk escalates from ring/web (standard) to subtotal/total occlusions (higher) to tortuous vessels (highest).

BPA Procedural Performance

• Guide extension catheters allow deep coaxial engagement, reducing contrast for S-iPA.
• Lesion severity assessed by S-iPA in orthogonal views (asymmetric stenoses can be missed in single projection).
• Angiographically patent vessels with abnormal venous return: assess resting pressure gradient; dilate until Pd:Pa ratio >0.80 or brisk venous return.
• Pd:Pa >0.80 threshold is empirical — not yet validated in well-powered studies.
• Failure to restore brisk venous return despite 1:1 balloon sizing + Pd:Pa >0.80 = secondary to underlying pulmonary arteriopathy → manage with pulmonary vasodilators.
• Chronically occluded subsegmental arteries may accommodate only small balloons initially; vessels remodel between sessions allowing larger balloon dilatation.
• Wire choice: nonhydrophilic soft-tip (<1 g tip load) 0.014-in coronary guide wires with J-shaped distal tip — minimises hemoptysis risk from respiratory motion-related perforation.
• BPA performed in one lung per session; 4–8 sessions typically required for complete revascularisation.
• Anticoagulation with i.v. heparin initiated after hemostasis; post-procedural inpatient monitoring 24–48 hours standard; outpatient 12–23 h monitoring at select expert centres.
• Follow-up RHC 3–6 months after BPA completion to assess need for additional BPA or medical therapy.

BPA Complications — Safety Trends

• Historical complication rates (Feinstein 2001): 6% mortality, 17% mechanical ventilation — halted initial BPA adoption.
• Mizoguchi et al. 2012 (Japan): Reported improved safety after procedural refinement, reinvigorated global interest.
• Meta-analysis of 26 studies (1675 patients, 7603 BPA procedures, 4 continents): Complications declining significantly:

• Lung injury (reperfusion pulmonary edema): most common complication; usually requires only supplemental O₂ for 2–4 hours ± NIPPV; severe cases may progress to intubation/ECMO.
• Risk factors for lung injury: worse baseline haemodynamics; higher-risk lesion subtypes.
• Hemoptysis: may indicate vascular injury — most cases self-resolve with or without anticoagulation reversal; severe cases require balloon tamponade, selective intubation, coil/gelatin foam occlusion.

Knowledge Gaps and Future Directions

• Imaging: Standardise subsegmental anatomy nomenclature; single imaging modality for acute + chronic thromboembolic disease; objective perfusion quantification tools.
• Patient selection: RCT data for BPA vs medical therapy in surgically inaccessible disease; BPA vs PEA in predominantly level 3 disease; BPA in CKD, parenchymal lung disease, multifactorial PH, post-PEA residual CTEPH.
• Procedural: BPA-specific equipment development; validate Pd:Pa >0.80 threshold; fusion CT-fluoroscopy imaging for navigation.
• Post-procedural: Protocols for pulmonary vasodilator wean after effective BPA; long-term PA branch patency data; rehabilitation efficacy after BPA.

Limitations of the Document

• Consensus statement without systematic review methodology — conclusions represent expert opinion not formal meta-analysis.
• Evidence base predominantly from Japanese single-centre registry series; external validity in Western populations and non-expert centres uncertain.
• Pd:Pa >0.80 adequacy threshold is empirical without prospective validation.
• Optimal riociguat pretreatment duration and weaning protocols post-BPA are undefined.
• No randomised data comparing BPA vs PEA for intermediate-risk (mid-distal segmental) disease.

Key Concepts Mentioned

• concepts/Balloon-Pulmonary-Angioplasty — primary subject; procedural framework, patient selection, complications
• concepts/Acute-PE-Clinical-Categories — CTEPH as post-PE complication
• concepts/PAH-Risk-Stratification — haemodynamic targets; riociguat role
• concepts/Right-Heart-Catheterization — Pd:Pa ratio; haemodynamic endpoints; post-BPA RHC

Key Entities Mentioned

• entities/CTEPH — primary disease entity; disease-level classification; PEA vs BPA decision
• entities/Pulmonary-Hypertension — haemodynamic context; Group 4 PH

Wiki Pages Updated

• wiki/sources/BPA-AHA-2024.md — created (this file)
• wiki/concepts/Balloon-Pulmonary-Angioplasty.md — created
• wiki/entities/CTEPH.md — BPA procedural details, lesion classification, RACE/MR BPA trial data, complication trends, expert centre criteria added
• wiki/sourceindex.md — updated
• wiki/wikiindex.md — updated