I was high risk in both my pregnancies. Took aspirin from ~13 weeks with my first, and from BFP with my second. Still got pre-eclampsia anyway. Though I was entirely symptomless other than high BP, protein in urine, and wonky liver enzymes. I seem to develop pre-eclampsia around 34 weeks. First time I missed the appointment that would have picked it up, second time an admin mistake meant the results from 34 weeks wasn't acted upon until 36 weeks.
In regards to additional antenatal care, there wasn't much different to any other pregnancy. I did have growth scans with my first, but that was due to raised PI found at my 20 week scan. As I didn't have raised PI in my second pregnancy I only received the normal scans (12,20, and 36 at my trust). I did see a consultant once at ~20weeks, but there's nothing they can do unless you do develop pre-eclampsia, so I was discharged back to midwife care. My second pregnancy I received the same appointment schedule as a FTM (i.e more appointments) to monitor my BP and urine. I also bought my own monitor to track BP in my second pregnancy.
Once I had developed pre-eclampsia, I was admitted to hospital immediately (36+1 both times), and advised to not leave until after I had my baby. While there I had 4 hourly checks, and was medicated to bring BP down. As baby and I were otherwise fine, induction was started at 37 weeks. Both DC were born healthy, large for gestation, and (other than a small amount of suction for DC2) needed no breathing support or SCBU/NICU stay. I remained on BP medication for 6 weeks with my first, and didn't need it post birth (kept sending my BP low) with my second.
Hopefully you won't develop pre-eclampsia. But if you do, it's taken extremely seriously, and you'll be monitored closely. If I, or baby, had showed any sign of deterioration, immediate induction, or even C-section would have happened. Best of luck with the rest of your pregnancy.