Balloon pulmonary angioplasty in chronic thromboembolic pulmonary hypertension

Abstract

Chronic thromboembolic pulmonary hypertension (CTEPH) is thought to result from incomplete resolution of pulmonary thromboemboli that undergo organisation into fibrous tissue within pulmonary arterial branches, filling pulmonary arterial lumina with collagenous obstructions. The treatment of choice is pulmonary endarterectomy (PEA) in CTEPH centres, which has low post-operative mortality and good long-term survival. For patients ineligible for PEA or who have recurrent or persistent pulmonary hypertension after surgery, medical treatment with riociguat is beneficial. In addition, percutaneous balloon pulmonary angioplasty (BPA) is an emerging option, and promises haemodynamic and functional benefits for inoperable patients. In contrast to conventional angioplasty, BPA with undersized balloons over guide wires exclusively breaks intraluminal webs and bands, without dissecting medial vessel layers, and repeat sessions are generally required. Observational studies report that BPA improves haemodynamics, symptoms and functional capacity in patients with CTEPH, but controlled trials with long-term follow-up are needed. Complications include haemoptysis, wire injury, vessel dissection, vessel rupture, reperfusion pulmonary oedema, pulmonary parenchymal bleeding and haemorrhagic pleural effusions. This review summarises the available evidence for BPA, patient selection, recent technical refinements and periprocedural imaging, and discusses the potential future role of BPA in the management of CTEPH.

FIGURE 1

a) Pulmonary angiography, showing a stenosis in the subsegment of the 10th segmental artery (anterior view); b) the catheter is introduced into a web stenosis; c) the wire is introduced between the fibrotic material and the balloon is inflated, leading to rupture of the web. d) Angiography after balloon pulmonary angioplasty shows an improvement of blood flow with better perfusion of the parenchyma and quick venous return. In contrast to pulmonary endarterectomy, the fibrous material is not removed from the arteries, but is crushed against the vessel wall.

FIGURE 2

Pulmonary arterial imaging before and after percutaneous balloon pulmonary angioplasty (BPA). a) Pre-procedure pulmonary angiogram demonstrating an intra-arterial fibrous “web” lesion; b) the corresponding intravascular ultrasound image showing the intravascular filling defect; c) the BPA balloon in place; d) pulmonary angiogram after the BPA procedure, showing the patent arterial lumen.

FIGURE 3

a–d) Selective angiograms and e–h) digital-subtraction angiograms of the right and left pulmonary arteries in a 76-year-old female with chronic thromboembolic pulmonary hypertension manifestation at the level of segmental and subsegmental branching. e–h) Image acquisition in the digital-subtraction angiography technique in frontal or lateral (90° left anterior oblique) projection using intra-arterial contrast injection (iomeprol 300 mg iodine·mL⁻¹, flow rate 12 mL·s⁻¹, volume per injection 35 mL, frame rate 7.5·s^-1).

FIGURE 4

a) Conventional pulmonary angiogram, with b) and c) corresponding optical coherence tomography images from a patient with chronic thromboembolic pulmonary hypertension, showing the nature of vascular obstructions at two locations. ^#: location for b); ^¶: location for c). Scale bars=1 mm.