Unmasking the severity of aortic stenosis by pharmacological elimination of left ventricular outflow tract obstruction: A case report

Background: Left ventricular outflow tract (LVOT) obstruction may occur with aortic stenosis (AS). However, the severity of AS is difficult to determine in this condition because the dynamic pressure gradient in LVOT obstruction influences the blood flow across the aortic valve. Case summary: A 74-year-old woman was referred to our hospital having complaints of exertional dyspnoea and chest pain. Transthoracic echocardiography demonstrated LVOT obstruction with peak pressure gradient of 93mmHg and 'moderate' AS with 3.m/s peak velocity and mean pressure gradient of 26mmHg. Coronary angiography did not indicate any significant coronary artery disease. The pressure gradients at LVOT and aortic valve were measured as 34mmHg and 76mmHg via a pressure wire-pullback analysis, respectively. Intravenous 2 mg propranolol and 70 mg cibenzoline were administered to minimize the LVOT obstruction. Subsequently, these pressure gradients changed to 2mmHg and 96mmHg, respectively. The patient was finally diagnosed with 'severe' AS concomitant with LVOT obstruction. Therefore, surgical aortic valve replacement and myectomy were performed to remove the double obstruction. Discussion: Herein, we present a case of 'double' LVOT obstruction due to dynamic myocardial component and fixed aortic component. Although the severity of AS is known to be influenced by LVOT obstruction, the present case is novel to demonstrate the phenomenon by using a pressure wire during pharmacological intervention. An accurate evaluation of the AS severity is important to provide adequate treatment. Therefore, the severity of AS should be evaluated while minimizing the LVOT obstruction.