AD9277 AAF question

Hi there,

I'm using the AD9277 in an ultrasound application and am wondering about the AAF limitation.  It looks like the AD9277 has a 387 kHz lower frequency limit (page 32 of the datasheet here - http://www.analog.com/static/imported-files/data_sheets/AD9277.pdf#page=32) within the high-pass of the AAF.  Can anyone comment on whether this frequency can be reduced by reducing the sample clock frequency, as in below 8 MHz?

Thanks!

-Paul