challenges in the diabetic foot 2016

Challenges in the Diabetic Foot

Diabetic Foot Protection ServiceTallaght Hospital, Dublin, Ireland

Sean Tierney

October 2016

Vascular surgery @ Tallaght

Vascular disease

Neuropathy

Deformity

Trauma

UlcerHealing Limb loss


Vascular disease

Neuropathy

Deformity

Trauma

UlcerHealing Limb loss

Ischaemia

Infection/Osteomyelitis


The challenges

• Is it neuropathic?

• Is it ischaemic? or both

• Is there osteomyelitis?

• Is it Charcot?

• What can we do about it?


Is there neuropathy?

Sensory

Motor

Autonomic


Sensory neuropathy

• -ve predictive value =

90%-98%

• +ve predictive value =

18%-36%

• 80% of foot ulcers and

100% of amputations

occur in those with loss of

sensation 32 mo followup

J Fam Pract. 2000;49:S30

Diabetes Care. 1992;15:1386


Ipswich Touch test

• If ≥2 (of 6) missed

• Sensitivity 77%

• Equivalent to

SWMF

Rayman G. Diabetes Care. Jul 2011; 34(7): 1517–1518.


Autonomic neuropathy


Motor neuropathy

Diabetes Care. 2001;24:1442

Diabetes Metab. 2003;29:261


Is it ischaemic?


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


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


ABI in Diabetes

Poitier et al, Eur J Vasc Endovasc 2011


<120s

60o

<120s

Beurger’s test

-ve +ve


Toe pressure

P>SBP


Toe pressure measurements

• Less affected by medial calcification

(neuropathy, CRF)

• absolute toe pressure of <30 mmHg =

critical ischemia

• 1o healing of DFU

– 85% TP >45 mmHg

– 36% ≤45 mmHg (p < .001) *

Brooks et al. Diabetic Medicine 2001, 18(12):528-532.

* Apelqvist et al. Diabetes Care June 1989 12:6 373-378


Tissue oxygenation


Tissue oximetry & healing

Londahl et al. Diabetolgia 2011


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


• TcPO2 best in comparative

analysis

• Poor methodology

• More research required


Is there osteomyelitis?


Clinical assessment

• Debride –

diagnostic and

therapeutic

• Probe wound -

?probes to bone

• ?Bone biopsy

• Imaging


Probes to bone

Malhotra et al Diabet Foot Ankle. 2014


Plain XRay

• osteopenia

• periosteal thickening

• cortical erosions

• new bone formation

• sequestrum

• 30–50% bone loss required (2–3

weeks)

• ? OM vs Charcot

sensitivity 54% specificity 68%

But NPV?



MRI

Kapoor A et al. Arch Intern Med. 2007

• Early

• Bone oedema

(overdiagnosis)

• vs Charcot ??

• “investigation of choice”

sensitivity 90% specificity 80%


Scintigraphy

• Tc-99m-Medronic

Acid

Bisphosphonate

• sensitivity 80-90%

specificity < 50%

• inflammatory or

trauma


Spect

• CT

• Isotope

• Tc-99m + CT or MRI

• ↑ specificity


Probes to bone



Is it Charcot?


Is it Charcot?

• Swelling

• Erythema

• Neuropathy 100%

• Pain 75%

vs cellulitis

vs osteomyelitis


Is it Charcot?

• Xray – normal

• MRI

• Antibiotics ↓


What to do?

Structural &

neuropathy


Neuropathic ulcer

Structural &

neuropathy

Offload

Lewis J et al. Cochrane Database Syst Rev. 2013


Neuropathic ulcer


What to do?

Structural &

neuropathy

Offload

Ischaemia

Osteomyelitis

Acute Charcot


Osteomelitis – antibiotics tx

• No sequestrum on Xray

• No systemic sepsis

+/- bone debridement/bx

• 4 studies highly selected

• 6/52 – 3/12 therapy + offloading

• Healing in 60-80%

• Urgent Sx in 1/3

• Recurrence in 1/3



Osteomelitis - surgery

• Antibiotics

• Sliding scale

• Surgical

Debridement – all

infected bone

• Drainage


Infection

• Multiple

procedures

• VAC closure

• Offloading


What to do?

Structural &

neuropathy

Offload

Ischaemia

Osteomyelitis

Drain,

debride, ABx

Acute Charcot


Acute Charcot

• Offload

• Non-wt bearing

• Assess stability

clinical & Xray

• Wait

• 9-12 months


What to do?

Structural &

neuropathy

Offload

IschaemiaOsteomyelitis

Drain,

debride, ABx

Acute Charcot

Offload


Vascular Intervention

Ischaemia

Revascularisation


Imaging

• Popliteal pulse

– Angio

• Femoral pulse

– Duplex

• ? Femoral pulse

– CT

Popposelli F. JVS 2010


Pedal Bypass surgery

0

20

40

60

80

100

0 6 12 18 24 30 36 42 48 54 60

Lim

b s

urv

iva

l a

s a

pe

rce

nta

ge

Time after surgery (months)

Limb Salvage

Good et al Ir J Med Sci 2010


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


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)

Su

rviv

al a

s a

pe

rce

nta

ge

Pedal Bypass surgery

Good et al Ir J Med Sci 2010


Options


Technical considerations

• Consent

• Ipsilateral

(antegrade)

• Local

• ? 4/5Fr

• ? ultrasound


Tibial angioplasty - results

• 40 mo

• 61 limbs in 53 patients

(41 male, median age

73)

• Rest pain /tissue loss)

• TASC D

O Connor et al ASGBI 2014


Tibial angioplasty – results 2

• Technical success

81.3% (49/61 limbs)

• 2o procedure

n=12 (4 distal bypass)

• Survival (3 y) 72%

• AFS (3 yr) 64%

O Connor et al ASGBI 2014


Tibial angioplasty – meta-analysis

• N = 2653

• Technical success = 90%

@ 3 years

• 1o patency 49%

• 2o patency 63%


• Survival 68%

Romiti et al J Vas Surg 2008


Tibial angioplasty – meta-analysis

• N = 2653

• Technical success = 90%

• @ 3 years

• 1o patency 49%

• 2o patency 63%


• 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.


Tibial artery disease

• Sub-intimal vs luminal

• Target vessels

• 50% better healing

rates

• Re-assessment

Lida O et al. J Vasc Surg. 2012; 55(2):363-370


The evidence?


Multidisciplinary care

Nason et al. Ir J Med Sci 2013

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challenges in the diabetic foot 2016

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