Abstract
After the Great East Japan Earthquake, the prevalence of deep vein thrombosis (DVT) in disaster shelters in Ishinomaki (Pacific coast, Japan) was found much higher than that ever reported in Japan. In Ishinomaki, twelve patients were found to have pulmonary thromboembolism for one month after the earthquake and DVT was found in 10 of those patients. The calf DVT was examined using sonography in the shelters (from March 2011 to July 2011) and in temporal emergency housings (from August 2011 to December 2011), and the results indicated that 190 of 701 evacuees had DVT. DVT prevalence was higher in evacuees in the tsunami-flooded shelters (127 of 371 evacuees, 34.2%) than in those in the non-flooded shelters (63 of 330 evacuees, 19.1%). This indicated that deteriorated and crowded condition in the tsunami-flooded shelters might induce thrombogenesis in calf veins. Therefore, evacuees were immediately recommended to leave tsunami-flooded areas. DVT prevalence in the shelters reduced gradually; however, this prevalence was found to be higher in the temporal emergency housings (32 of 360 evacuees, 8.9%) than in the non-disaster area in Japan (2.2% in Yokohama city). The risk of calf DVT in the temporal emergency housings increased because of reduced blood flow in the calf veins caused by immobility. The residents of the housings require to be physically active in order to avoid calf DVT.
