A diagnostic challenge: unveiling chronic thromboembolic pulmonary hypertension in the absence of visible thrombi: a case report

Background: Chronic thromboembolic pulmonary hypertension (CTEPH) is a severe condition characterized by persistent dyspnoea and hypoxia. Diagnosis is challenging, especially when computed tomography pulmonary angiography (CTPA) shows no visible thrombi and symptoms overlap with common conditions like heart failure. Case summary: We present a 77-year-old female with heart failure with preserved ejection fraction who experienced progressive, refractory dyspnoea and hypoxia. Despite a CTPA showing no large, organized thrombi, a strong clinical suspicion prompted a ventilation/perfusion (V/Q) scan. The scan revealed multiple mismatched perfusion defects, confirming CTEPH. A workup for an incidental right ventricular thrombus did not reveal an underlying prothrombotic state. Discussion: This case highlights the diagnostic difficulties of CTEPH when confounded by comorbidities. Persistent, unexplained hypoxia should trigger a comprehensive evaluation that includes a V/Q scan, which remains the gold standard screening tool due to its high sensitivity. The management approach for inoperable patients requires careful consideration of approved medical therapies and patient-specific factors.