Clinically Worsening Chronic Thromboembolic Pulmonary Hypertension by Riociguat After Balloon Pulmonary Angioplasty.

Riociguat, a soluble guanylate cyclase stimulator, induces pulmonary artery dilatation through blood flow and is effective in treating chronic thromboembolic pulmonary hypertension (CTEPH). There are two types of vasculopathies in CTEPH based upon its location, in other words, proximal or distal to the thrombus-medicated obstruction. Distal vasculopathy is characterized by intrapulmonary shunts due to diminished blood flow. While other therapeutic interventions for CTEPH including pulmonary endarterectomy and balloon pulmonary angioplasty achieve reperfusion to the distal vasculopathy vessels, the effects of riociguat on distal vasculopathy vessels remain undetermined. Herein, we describe a case of a 66-year-old woman who exhibited deterioration of mean pulmonary artery pressure and exercise tolerance after a 4-month treatment with riociguat. She received balloon pulmonary angioplasty prior to riociguat administration. Her lung perfusion scintigraphy and pulmonary angiography findings did not change over the course of treatment. Notably, after the discontinuation of riociguat, her clinical values returned to their levels prior to riociguat administration. Her intrapulmonary shunt ratio followed a similar course as her hemodynamic status. We demonstrate that riociguat can deteriorate hemodynamic status, which may mediate the dilatation of intrapulmonary shunts. We should perform close monitoring of symptoms and hemodynamic status after riociguat administration, especially in patients in whom the reperfused DVs occurred due to invasive treatment.