Answer
The reflected frequency would be less.
Work Step by Step
If $\theta = 0^{\circ}$ and the blood flow is in the opposite direction from the incoming sound wave, the reflected frequency is a maximum.
If $\theta = 90^{\circ}$ and the blood flow is perpendicular to the direction from the incoming sound wave, the reflected frequency is a minimum, and the reflected frequency is the same as the original frequency.
Thus, if angle $\theta$ were greater, the angle would be closer to $90^{\circ}$ and the reflected frequency would be less.
