β遮断薬およびrenin–angiotensin–aldosterone系拮抗薬によってsteroid療法から離脱し得たFontan手術後タンパク漏出性腸症の2自験例

Due to the lack of a ventricle to pump blood to the pulmonic circuit, Fontan circulation induces high central venous pressure and low cardiac output. This may lead to the onset of protein-losing enteropathy (PLE). We report on two patients with PLE after Fontan type operation who were treated successfully with Beta-blockers and Renin‒Angiotensin‒Aldosterone System Blockers following steroids. Both patients had right isomerism, a functionally single ventricle, and post-operative fenestrated total cavopulmonary connection. They developed PLE after fenestration closure. We initially used prednisolone (PSL) to improve PLE and performed cardiac catheterization when protein loss ceased. Based on hemodynamic data, we administered four agents and increased their doses: a beta blocker, an angiotensin-converting enzyme inhibitor, an angiotensin II receptor blocker, and spironolactone. The PSL dose was tapered gradually over 7‒8 months. On remission by PSL, both cases showed reduced cardiac index (CI) and right ventricular ejection function (RVEF), and increased systemic vascular resistance (SVR) and ratio of the right ventricular end-diastolic pressure to CI (RVEDP/CI). When PSL was discontinued, both cases showed reduced SVR and RVEDP/CI and improved CI and RVEF. Concomitant administration of a sympathetic blocking agent and renin‒angiotensin‒aldosterone system inhibitors may be a treatment option for PLE after a Fontan operation. Increased SVR may occur as a reaction to low cardiac output, and it may cause dysfunction of the systemic ventricle and further low cardiac output. These sequences may be a cause of PLE.