Pulmonary Hypertension as a Possible Cause of Paradoxical Low-Flow, Low-Gradient Aortic Stenosis

Paradoxical low-flow, low-gradient aortic stenosis (LFLG AS) is recognized as a subtype of aortic stenosis. A small left ventricular (LV) cavity with marked LV concentric remodeling leads to a reduced stroke volume in this condition. The case is reported of a paradoxical LFLG AS patient who was undergoing treatment for pulmonary hypertension (PH) and interstitial pneumonia associated with scleroderma. Echocardiography demonstrated enlargement of the right ventricle and a diminished LV cavity. Moreover, the aortic valve opening was restricted despite a preserved LV ejection fraction (61%). The patient's aortic valve area (obtained with the continuity equation) was 0.57 cm2 (indexed AVA was 0.39 cm2/m2), and the mean gradient was 16 mmHg. Multi-detector computed tomography findings confirmed that the aortic valve calcification was not severe. The main mechanism responsible for LFLG AS was considered to be a reduced LV cavity secondary to PH, rather than a sclerotic aortic valve. Thus, a decision was taken to treat the patient with additional medical management prior to performing any invasive procedures. It should be borne in mind that PH can lead to paradoxical LFLG AS, and that appropriate treatment should be contemplated depending on the underlying mechanisms. Video 1: Transthoracic echocardiography in the parasternal long-axis view showing right ventricular dilatation and a diminished left ventricular cavity. Video 2: Transthoracic echocardiography in the shortaxis view showing enlargement of the right ventricle and septal flattening due to pulmonary hypertension. Video 3: Transesophageal echocardiography clearly demonstrates an insufficient valve opening.