橋本病を合併した大動脈弁狭窄症の術前管理に経時的血中BNP測定および推定double productが有用であった1例

Plasma Brain Natriuretic Peptide(BNP) and Estimated Double Product are Useful for Preoperative Management of Aortic Stenosis with Hashimoto's Disease：A case report

患者は72歳女性．労作時胸痛を認め，心臓超音波検査および心臓カテーテル検査により重症大動脈弁狭窄症(aortic stenosis：AS)と未治療の橋本病合併が認められた．術前から少量の甲状腺ホルモン補充療法開始により大動脈左室圧較差(Ao-LVPG)増大，胸痛，不整脈などの出現が危惧された．経時的な甲状腺ホルモン，脳性ナトリウム利尿ペプチド(BNP)測定および心臓超音波検査を行い，左室負荷の指標として推定double product〔(収縮期体血圧＋平均Ao-LVPG)×心拍数〕を検討した．経過中Ao-LVPG増大は認めず，推定double product上昇が認められ，BNPの推移と一致していた．ASにおける新たな心負荷増大の指標としてBNPと同等に術前管理に有用である可能性が示唆され，従来報告がないことから文献的考察を加え報告する．

A 72-year-old woman was referred to our hospital with exertional chest pain. We diagnosed severe aortic stenosis (aortic valve area: 0.5-0.6cm², transaortic gradient: 62-78.8mmHg) by echocardiography and cardiac catheterization. She also had untreated Hashimoto's disease. Thyroid hormone therapy was necessary to prevent post operative complications, but the administration of an adequate dose could lead to chest pain and arrhythmia in patients with severe aortic stenosis. During thyroid hormone administration, we monitored plasma brain natriuretic peptide(BNP) and the transaortic gradient by echocardiography. We also examined the estimated double product〔(systemic blood pressure＋mean transaortic gradient)×heart rate〕as an indicator of the condition of the left ventricular due to aortic stenosis. During follow-up, the estimated double product showed similar changes to those of BNP, unlike the transaortic gradient. Aortic valve replacement was carried out on the 54th day without postoperative complications. BNP measurement was not rapid while the transaortic gradient measured by echocardiography could not be used to evaluate the cardiac load. In contrast the estimated double product was an easy, and quick method of evaluating cardiac load.