AAA PAD research proposal Matt Bown

1. Is AAAscreening an opportunity to
screen for other cardiovascular
disease?
Matt Bown, Professor of Vascular Surgery, Director of Clinical
Academic Training, College of Life Sciences, University of
Leicester

2. Is AAA screening an opportunity to screen for
other cardiovascular disease?
Matt Bown
University of Leicester
www.le.ac.uk

3. Why screen for AAA

4. Trouble ahead?
0.8%
0.9%
1.0%
1.1%
1.2%
1.3%
1.4%
1.5%
1.6%
1.7%
1.8%
Prevalence
Screening year

5. NAAASP Strengths
• Patient centred
• High attendance
• Trained workforce
• Quality assurance
• Enthusiasm!

6. Multi-disease screening
• AAA
• + BP
• + ABPI

7. Multi-disease screening
• ↓ mortality
• ↓ PAD bed-days
• ↓ BP bed-days
• ↑ QoL

8. Research proposal
Does the addition of screening for peripheral arterial
disease to AAA screening improve the health of men
invited for screening?
What is the best screening test for PAD?
How do we add PAD screening to AAA screening?
How might we run a trial in NAAASP?

9. What screening test?
• Men, programmes and accuracy need to be considered.

10. Project plan
1. Select a screening tool
2. Test acceptability and accuracy
3. Small scale feasibility study of PAD+AAA screening
4. Multi-centre randomized trial of PAD+AAA screening

11. Project plan
1. Select a screening tool
2. Test acceptability and accuracy
3. Small scale feasibility study of PAD+AAA screening
4. Multi-centre randomized trial of PAD+AAA screening

12. Sample size consideration
• Outcome: cardiovascular events/deaths.
• 19% at 5 years in men invited for AAA screening
• Intervention may have small effects
• Need to randomize around 50,000 to 90,000 men

13. Trial design options
• Individual randomization
• Group randomization
– GP practices
– CCGs
– NAAASP units

14. Individual randomization
50,000 men
1 2 3 4 5 6 7 8 9 10

15. Individual randomization
50,000 men
25,000 men
PAD+AAA screening
25,000 men
AAA screening
1 2 3 4 5 6 7 8 9 10
Randomize

16. Individual randomization
50,000 men
25,000 men
PAD+AAA screening
25,000 men
AAA screening
1 2 3 4 5 6 7 8 9 10
1 2 3 4 5 6 7 8 9 10
Randomize

17. Individual randomization
50,000 men
25,000 men
PAD+AAA screening
25,000 men
AAA screening
1 2 3 4 5 6 7 8 9 10
1 2 3 4 5 6 7 8 9 10
Randomize

18. Group randomization: NAAASP units
1 2 3 4 5 6 7 8 9 10

19. Group randomization: NAAASP units
1 2 3 4 5 6 7 8 9 10
Randomize

20. Group randomization: NAAASP units
25,000 men
AAA screening
1 2 3 4 5 6 7 8 9 10
1 7 8 2 10
Randomize

21. Group randomization: NAAASP units
25,000 men
PAD+AAA screening
25,000 men
AAA screening
1 2 3 4 5 6 7 8 9 10
1 7 8 2 10 9 3 6 4 5
Randomize

22. Group randomization: GP practices (e.g.)
1 … … … … … … … … 99
NAAASP
Unit
NAAASP
Unit

23. Group randomization: GP practices (e.g.)
1 … … … … … … … … 99
1 … … … 99 … … … … …
Randomize
NAAASP
Unit
NAAASP
Unit

24. Group randomization: GP practices (e.g.)
2,500 men
PAD+AAA screening
2,500 men
AAA screening
1 … … … … … … … … 99
1 … … … 99 … … … … …
Randomize
NAAASP
Unit
NAAASP
Unit

25. Other options
NAAASP
Unit 1
NAAASP
Unit 2
NAAASP
Unit 3
Year/quarter
1
AAA
AAA
AAA

26. Other options
NAAASP
Unit 1
NAAASP
Unit 2
NAAASP
Unit 3
Year/quarter
1
Year/quarter
2
AAA AAA
AAA
AAA
PAD+AAA
AAA

27. Other options
NAAASP
Unit 1
NAAASP
Unit 2
NAAASP
Unit 3
Year/quarter
1
Year/quarter
2
Year/quarter
3
AAA AAA AAA
AAA
AAA
PAD+AAA PAD+AAA
AAA PAD+AAA

28. Other options
NAAASP
Unit 1
NAAASP
Unit 2
NAAASP
Unit 3
Year/quarter
1
Year/quarter
2
Year/quarter
3
Year/quarter
4
AAA AAA AAA PAD+AAA
AAA
AAA
PAD+AAA PAD+AAA PAD+AAA
PAD+AAAAAA PAD+AAA

29. What schema is most acceptable/practical?
• Individual randomization:
– Even chance for all men
– All units involved
– Less impact on individual clinics?
• Group randomization
– Less waiting room contamination?
– Easier to organize?
• GP vs CCG vs NAAASP unit
– Some units may not get to do new methods

30. Help
m.bown@le.ac.uk