Cardio exercise should help you lower your blood pressure. But if you've been regularly riding your bike for quite a while, then I doubt you get any significant drop just by changing the type of cardio you do. But who knows. I'm sure the results either of us would find is just circumstantial.

Not sure what the point is to know blood pressure just after exercise. But I suppose if power output is equal for the same amount of time then maybe you can say something is better or worse.