Chronic Thromboembolic Pulmonary Hypertension — Balloon Pulmonary Angioplasty (BPA)

Chronic thromboembolic pulmonary hypertension (CTEPH) is a unique pulmonary vascular disease arising from incomplete thrombus resolution after acute pulmonary embolism, in which fibrotic, organized thrombi cause chronic obstruction of pulmonary arteries leading to elevated pulmonary vascular resistance, right ventricular failure and exertional dyspnea. Pulmonary endarterectomy (PEA) is the curative treatment of choice; balloon pulmonary angioplasty (BPA) and medical therapy (riociguat, treprostinil, selexipag) are reserved for inoperable disease or residual/recurrent PH after PEA.

BPA originated in Japan in the early 2000s and has been refined into a staged, multidisciplinary intervention performed at expert centers. It targets distal segmental and subsegmental arteries inaccessible to surgical PEA, using small balloons (2–8 mm) under intravascular imaging guidance (OCT, IVUS) and selective angiography. Lesion morphology classification (web, ring, abrupt taper, slit-like, tortuous, occlusion) guides balloon sizing and pressure to minimize reperfusion injury.

Typical BPA program involves 4–8 staged sessions, treating one or two lobes per session to limit reperfusion lung injury. Mean PAP typically drops from 40–50 to 25–30 mmHg, PVR halves, 6MWD improves by 50–100 m, and WHO functional class advances by 1–2 levels. Complications include reperfusion lung injury (10–30%, more with high mean PAP and aggressive dilation), pulmonary artery dissection or perforation (5–10%), hemoptysis (5–15%), contrast-induced nephropathy. Long-term outcomes show sustained improvement and survival comparable to PEA in selected cohorts.