Assessment in the diabetic foot

1. Think Feet!
Diabetic Foot Protection Service
Tallaght Hospital, Dublin, Ireland
Sean Tierney

2. Vascular surgery @ Tallaght
“…the enormity of the global burden of
diabetic foot disease…this much neglected,
but potentially devastating, complication of a
disease that is reaching epidemic
proportions…Someone, somewhere, loses a
leg because of diabetes every 30 seconds of
everyday…”
Lancet 2005; 366:1674

3. Vascular surgery @ Tallaght
The diabetic foot – natural history
• Diabetes
– 3.5% population
– 5% of total healthcare spend
– 10% of hospital admissions
• Foot burden
– 2.5–10% incident ulcers/yr
– .25-1.8% amputations/yr
–  x 8 amputation risk
– 9/1000 diabetic have a foot ulcer at
one time

4. Vascular surgery @ Tallaght
• 50% of amputations
are above knee
• 50% of patients
require a second
major amputation
within 5 years
• 50% of patients dead
within 5 years
Clinical Care of the Diabetic Foot, 2005
Implications

6. Vascular surgery @ Tallaght
Neuropathy
http://goo.gl/oOQG4q
High glucose x
time 
• Sorbitol
accumulation
• Protein glycation
• Oxidative stress
• Micro-ischaemia

7. Vascular surgery @ Tallaght
Neuopathy
http://goo.gl/oOQG4q
0
20
40
60
80
100
0 25
Yrs
%

8. Vascular surgery @ Tallaght
Clawing of the toes
Risk Level
Foot Ulcer
%/yr
% in clinics
(diabetes clinics)
3: Prior amputation
Prior ulcer
28.1%
18.6%
7%
2: Insensate and
foot deformity or
absent pedal
pulses
6.3% 10%
1: Insensate 4.8% 17%-30%
0: All normal 1.7% 66%
Diabetes Care. 2001;24:1442
Diabetes Metab. 2003;29:261

9. Vascular surgery @ Tallaght
Clawing of the toes
Risk Level
Foot Ulcer
%/yr
% in clinics
(diabetes clinics)
3: Prior amputation
Prior ulcer
28.1%
18.6%
7%
2: Insensate and
foot deformity or
absent pedal
pulses
6.3% 10%
1: Insensate 4.8% 17%-30%
0: All normal 1.7% 66%
Diabetes Care. 2001;24:1442
Diabetes Metab. 2003;29:261

10. Vascular surgery @ Tallaght
Other foot deformity
• Claw toes
• Hammer toes
• Hallux valgus
• Pes Cavus
• Toe amputations
• Charcot

11. Vascular surgery @ Tallaght
Autonomic neuropathy & Callous

12. Vascular surgery @ Tallaght
Arterial supply
Poitier et al, Eur J Vasc Endovasc 2011
• PAOD prevalence
9.5% - 13.6%
• (~ 50% with ulcer)
• distal > proximal
• Medial artery
calcification more
common

13. Vascular surgery @ Tallaght
Mechanism of ulceration
Neuropathy
Deformity
Trauma
Ulcer

14. Vascular surgery @ Tallaght
Vascular disease
Neuropathy
Deformity
Trauma
UlcerHealing

15. Vascular surgery @ Tallaght
Vascular disease
Neuropathy
Deformity
Trauma
UlcerHealing Limb loss
Ischaemia
Infection

16. Vascular surgery @ Tallaght
Risk assessment for foot ulceration
Structural
Skin and soft tissue
Innervation
Perfusion

17. Vascular surgery @ Tallaght
Semmes-Weinstein monofilament
• Loss of
– protective sensation in feet
– proprioception
– vibration
– Pain
• Asymptomatic
– 50% of insensate patients
have no symptoms
Sensory neuropathy
Diabetes Care. 2006;2 9: S24
Diabetes Care. 2004; 27: 1591

18. Vascular surgery @ Tallaght
• Demonstrate on forearm or hand
• Place monofilament perpendicular
& bow into C-shape for 1 second
• 4 sites/foot
• Avoid
– Heel (does not predict ulcer)
– calluses, scars, and ulcers
Sensory neuropathy
Diabetes Care. 2006;2 9: S24
Diabetes Care. 2004; 27: 1591

19. Vascular surgery @ Tallaght
Sensory neuropathy
• -ve predictive value
= 90%-98%
• +ve predictive value
= 18%-36%
J Fam Pract. 2000;49:S30
Diabetes Care. 1992;15:1386

20. Vascular surgery @ Tallaght
Ipswich Touch test
• If ≥2 (of 6) missed
• Sensitivity 77%
• Equivalent to
SWMF
Rayman G. Diabetes Care. Jul 2011; 34(7): 1517–1518.

21. Vascular surgery @ Tallaght
Foot assessment in diabetics
Structural
Skin and soft tissue
Innervation
Perfusion

22. Vascular surgery @ Tallaght
Vascular assessment in diabetics
 Clinical assessment
 Peripheral pulses
 Ankle brachial pressure
indices
 Toe (brachial) pressure
indices
 Tissue oximetry

23. Vascular surgery @ Tallaght
Palpating pulses

24. Vascular surgery @ Tallaght
Is palpation of pulses reliable?
DP only PT only Both
Sensitivity 64 70 73
Specificity 81 83 92
NPV * 91 92 94
PPV 43 49 81
Accuracy 77 81 95
absent pulses
• Negative predictive value of palpable pulses in excluding PAOD
is 94% (vs ABI <0.9 as gold standard)
Armstrong et al. Can J Cardiol 2010

25. Vascular surgery @ Tallaght
Risk based ulcer prevention
Risk Level
Foot Ulcer
%/yr
% in clinics
(diabetes clinics)
3: Prior amputation
Prior ulcer
28.1%
18.6%
7%
2: Insensate and
foot deformity or
absent pedal
pulses
6.3% 10%
1: Insensate 4.8% 17%-30%
0: All normal 1.7% 66%

26. Vascular surgery @ Tallaght
Risk based ulcer prevention
Risk Level
Foot Ulcer
%/yr
% in clinics
(diabetes clinics)
3: Prior amputation
Prior ulcer
28.1%
18.6%
7%
2: Insensate and
foot deformity or
absent pedal
pulses
6.3% 10%
1: Insensate 4.8% 17%-30%
0: All normal 1.7% 66%
Education
Annual community screening

27. Vascular surgery @ Tallaght
Risk based ulcer prevention
Risk Level
Foot Ulcer
%/yr
% in clinics
(diabetes clinics)
3: Prior amputation
Prior ulcer
28.1%
18.6%
7%
2: Insensate and
foot deformity or
absent pedal
pulses
6.3% 10%
1: Insensate 4.8% 17%-30%
0: All normal 1.7% 66%
Education
Regular podiatry & screening

28. Vascular surgery @ Tallaght
Risk based ulcer prevention
Risk Level
Foot Ulcer
%/yr
% in clinics
(diabetes clinics)
3: Prior amputation
Prior ulcer
28.1%
18.6%
7%
2: Insensate and
foot deformity or
absent pedal
pulses
6.3% 10%
1: Insensate 4.8% 17%-30%
0: All normal 1.7% 66%
Regular podiatry & screening
Footwear & insoles

29. Vascular surgery @ Tallaght
Active ulcer

30. Vascular surgery @ Tallaght
Active ulcer
?
infection
?
ischaemia

31. Vascular surgery @ Tallaght
Active ulcer
• Debride
• Xray
• ? Bone scan
• ? MRI
• Offload
– TCC
– Removable cast
• Reassess
• Footwear

32. Vascular surgery @ Tallaght
Infection
• Clinical rather
than microbiology
Osteomyelitis
• Probes to bone
• MRI ?
• Bony destruction

33. Vascular surgery @ Tallaght
Infection
• Antibiotics
• Sliding scale
• Surgical
Debridement
• Drainage
• Minor amputation

34. Vascular surgery @ Tallaght
Infection
• Multiple
procedures
• VAC closure
• Offloading

35. Vascular surgery @ Tallaght
Where is the patient on the spectrum?
Normal pulses
Impalpable pulses

36. Vascular surgery @ Tallaght
Other clinical signs
• Colour
• Temperature
• Hair loss
• Shiny Skin
Inconsistent & unreliable

37. Vascular surgery @ Tallaght
Beurger’s test - 1

38. Vascular surgery @ Tallaght
Beurger’s test - 2
60o
<120s

39. Vascular surgery @ Tallaght
Beurger’s test - 3
<120s

40. Vascular surgery @ Tallaght
Beurger’s test
Insall et al, J R Soc Med 1989

41. Vascular surgery @ Tallaght
Ankle brachial index

42. Vascular surgery @ Tallaght
ABI in Diabetes
Poitier et al, Eur J Vasc Endovasc 2011

43. Vascular surgery @ Tallaght
ABI in Diabetes
Poitier et al, Eur J Vasc Endovasc 2011

44. Vascular surgery @ Tallaght
Toe pressures

45. Vascular surgery @ Tallaght
Toe pressure
P>SBP

46. Vascular surgery @ Tallaght
Toe pressure measurements
• Less affected by medial calcification
• (neuropathy, CRF)
• false positive results rare
• absolute toe pressure of <30 mmHg =
critical ischemia
• Probably not required in routine
assessment
Brooks B, Dean R, Patel S, Wu B, Molyneaux L, Yue DK: TBI or not TBI: that
is the question. Is it better to measure toe pressure than ankle pressure
in diabetic patients? Diabetic Medicine 2001, 18(12):528-532.

47. Vascular surgery @ Tallaght
Tissue oxygenation

48. Vascular surgery @ Tallaght
Tissue oximetry & healing
Londahl et al. Diabetolgia 2011

49. Vascular surgery @ Tallaght
Tissue oximetry (summary)
• tissue hypoxia is defined as “a TcPO2 <40 mm Hg”
• associated with reduced likelihood of amputation
healing
• in critical limb ischemiaTcPO2 typically < 30 mm Hg
Oxygen response
• TcPO2 increases by > 40 mm Hg on 100% O2
usually associated with subsequent healing
Fife et al. Undersea and Hyperbaric Medicine. 2009

50. Vascular surgery @ Tallaght
Choices
Structural &
neuropathy
Offload
Ischaemia
Revascularisation
Infection
Drain,
debride, ABx

51. Vascular surgery @ Tallaght
Foot Protection Clinic
Nason et al. Ir J Med Sci 2013

52. Vascular surgery @ Tallaght
Vascular Intervention

53. Vascular surgery @ Tallaght
Pedal Bypass surgery
• 1998-2008
• N= 28 (4 asynchronous
bilateral)
• M:F = 5:1
• Mean age 63y (37 – 92)
• Autologous vein used in
all patients
Good et al Ir J Med Sci 2010

54. Vascular surgery @ Tallaght
Pedal Bypass surgery
Good et al Ir J Med Sci 2010
Proximal site
• Popliteal (n=28)
Distal sites
• Dorsalis paedis (n=13)
• Plantar artery (n= 15)

55. Vascular surgery @ Tallaght
Pedal Bypass surgery
Primary graft patency
0
20
40
60
80
100
0 6 12 18 24 30 36 42 48 54 60
Time after surgery (months)
Graftpatencyasapercentage
Primary
patency
Good et al Ir J Med Sci 2010

56. Vascular surgery @ Tallaght Primary & Secondary graft patency
0
20
40
60
80
100
0 6 12 18 24 30 36 42 48 54 60
Time after surgery (months)
Graftpatencyasapercentage
Primary
Secondary
Pedal Bypass surgery
Good et al Ir J Med Sci 2010

57. Vascular surgery @ Tallaght
Pedal Bypass surgery
0
20
40
60
80
100
0 6 12 18 24 30 36 42 48 54 60
Limbsurvivalasapercentage
Time after surgery (months)
Limb Salvage
Good et al Ir J Med Sci 2010

58. Vascular surgery @ Tallaght
Patient Survival after Popliteo-pedal bypass
0
20
40
60
80
100
0 6 12 18 24 30 36 42 48 54 60
Time after surgery (months)
Survivalasapercentage
Pedal Bypass surgery
Good et al Ir J Med Sci 2010

59. Vascular surgery @ Tallaght
Meta-analysis (pop pedal bypass)
• N=1,2320 (79
studies)
• @ 5 years
• 1o patency 63%
• 2o patency 71%
• Limb salvage 78%
• * 5 yr mortality ~50%
Albers et al J Vasc Surg. 2006 43:498-503.
*Hinchcliffe et al Diabetes Metab Res Review 2012

60. Vascular surgery @ Tallaght
Innovation

61. Vascular surgery @ Tallaght
Tibial artery disease

62. Vascular surgery @ Tallaght
Tibial artery disease

63. Vascular surgery @ Tallaght
Tibial artery disease

64. Vascular surgery @ Tallaght
Tibial angioplasty - results
• Jan 2010-June 2013
• 61 limbs in 53 patients (41 male, median age
73)
• Rest pain /tissue loss)
• Infrapopliteal disease extent: TASC D
• Co-morbidities
– 36/53 Diabetic
– 31/53 Smoker
– 18/53 Chronic kidney disease stage 4-5
O Connor et al ASGBI 2014

65. Vascular surgery @ Tallaght
Tibial angioplasty – results 2
• Technical success 81.3% (49/61 limbs)
• 55% (29/53) > one tibial vessel treated
• 24% (13/53) proximal lesion (SFA or Pop)
treated synchronously
• Adjuvant procedures:
– Minor amputation or debridement :12/61 limbs
– Mechanical thrombectomy(Rotoarex): 6/61 limbs
– Intra-op thrombolysis: 6/61 limbs
O Connor et al ASGBI 2014

66. Vascular surgery @ Tallaght
Tibial angioplasty - followup
• Mean follow up 17months (1-42)
• Major Amputation rate 10% (6/61 limbs)
• Revascularisation required in 12 pts
– 8 repeat angioplasty
– 4 distal bypass
• Overall survival at 3 years: 72%
• Amputation free survival at 3 years : 64%
• Poor survival associated with chronic kidney
disease
O Connor et al ASGBI 2014

67. Vascular surgery @ Tallaght
Tibial angioplasty – meta-analysis
• N = 2653
• Technical success = 90%
• @ 3 years
• 1o patency 49%
• 2o patency 63%
• Limb salvage 80%
• Survival 68%
Romiti et al J Vas Surg 2008

68. Vascular surgery @ Tallaght
Tibial angioplasty – meta-analysis
• N = 2653
• Technical success = 90%
• @ 3 years
• 1o patency 49%
• 2o patency 63%
• Limb salvage 80%
• Survival 68%
Romiti et al J Vas Surg 2008
vs Bypass (@5 years)
63%
71%
78%
50%
Albers et al J Vasc Surg. 2006 43:498-503.

69. Vascular surgery @ Tallaght
Tallaght data
Nason et al. Ir J Med Sci 2013

70. Vascular surgery @ Tallaght
Amputations
AKA
BKA
0
2
4
6
8
10
12
Study Period
Control
Period
Nason et al. Ir J Med Sci 2013

71. Vascular surgery @ Tallaght
Length of stay
15 days 12 days
Nason et al. Ir J Med Sci 2013

72. Vascular surgery @ Tallaght
Total bed days used
2842
2485
Bed Days Used
Control Period Study Period
13%
Nason et al. Ir J Med Sci 2013

73. Vascular surgery @ Tallaght
Total bed days used
2842
2485
Bed Days Used
Control Period Study Period
€300,000
*€ 890 per dayNason et al. Ir J Med Sci 2013

74. Vascular surgery @ Tallaght
Think feet… think vascular

75. www.perfuse.net
@theseant
http://www.slideshare.net/stierney
http://goo.gl/jmtHb3