title: The authors reply.
authors.affiliation: Department of Clinical Epidemiology and Health Economics, School of Public Health, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
authors.forename: Shotaro
authors.initials: S
authors.lastname: Aso
authors.forename: Hideo
authors.initials: H
authors.lastname: Yasunaga
mesh_terms: D016208:Databases, Factual; D015199:Extracorporeal Membrane Oxygenation; D007297:Inpatients; D007423:Intra-Aortic Balloon Pumping