The thromboembolic event rate was low in the modified preparation group ( @ of @ -LSB- @ % -RSB- ) compared with the standard preparation group ( @ of @ -LSB- @ % -RSB- ; adjusted risk difference , -@ % -LSB- @ % CI , -@ % to -@ % -RSB- ; P = @ ) , which had a higher thromboembolic risk than the non-HTPR group ( @ of @ -LSB- @ % -RSB- ; adjusted risk difference , @ % -LSB- @ % CI , @ % to @ % -RSB- ; P = @ ) .