Challenges in the Diabetic Foot Diabetic Foot Protection Service Tallaght Hospital, Dublin, Ireland Sean Tierney October 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 surgery @ Tallaght
Vascular disease
Neuropathy
Deformity
Trauma
UlcerHealing Limb loss
Ischaemia
Infection/Osteomyelitis
Vascular surgery @ Tallaght
The challenges
• Is it neuropathic?
• Is it ischaemic? or both
• Is there osteomyelitis?
• Is it Charcot?
• What can we do about it?
Vascular surgery @ Tallaght
Is there neuropathy?
Sensory
Motor
Autonomic
Vascular surgery @ Tallaght
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
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.
Vascular surgery @ Tallaght
Autonomic neuropathy
Vascular surgery @ Tallaght
Autonomic neuropathy
Vascular surgery @ Tallaght
Motor neuropathy
Diabetes Care. 2001;24:1442
Diabetes Metab. 2003;29:261
Vascular surgery @ Tallaght
Is it ischaemic?
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
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
Vascular surgery @ Tallaght
ABI in Diabetes
Poitier et al, Eur J Vasc Endovasc 2011
Vascular surgery @ Tallaght
ABI in Diabetes
Poitier et al, Eur J Vasc Endovasc 2011
Vascular surgery @ Tallaght
<120s
60o
<120s
Beurger’s test
-ve +ve
Vascular surgery @ Tallaght
Toe pressure
P>SBP
Vascular surgery @ Tallaght
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
Vascular surgery @ Tallaght
Tissue oxygenation
Vascular surgery @ Tallaght
Tissue oximetry & healing
Londahl et al. Diabetolgia 2011
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
Vascular surgery @ Tallaght
• TcPO2 best in comparative
analysis
• Poor methodology
• More research required
Vascular surgery @ Tallaght
Is there osteomyelitis?
Vascular surgery @ Tallaght
Clinical assessment
• Debride –
diagnostic and
therapeutic
• Probe wound -
?probes to bone
• ?Bone biopsy
• Imaging
Vascular surgery @ Tallaght
Probes to bone
Malhotra et al Diabet Foot Ankle. 2014
Vascular surgery @ Tallaght
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?
Malhotra et al Diabet Foot Ankle. 2014
Vascular surgery @ Tallaght
MRI
Kapoor A et al. Arch Intern Med. 2007
• Early
• Bone oedema
(overdiagnosis)
• vs Charcot ??
• “investigation of choice”
sensitivity 90% specificity 80%
Vascular surgery @ Tallaght
Scintigraphy
• Tc-99m-Medronic
Acid
Bisphosphonate
• sensitivity 80-90%
specificity < 50%
• inflammatory or
trauma
Vascular surgery @ Tallaght
Spect
• CT
• Isotope
• Tc-99m + CT or MRI
• ↑ specificity
Vascular surgery @ Tallaght
Probes to bone
Malhotra et al Diabet Foot Ankle. 2014
Vascular surgery @ Tallaght
Is it Charcot?
Vascular surgery @ Tallaght
Is it Charcot?
• Swelling
• Erythema
• Neuropathy 100%
• Pain 75%
vs cellulitis
vs osteomyelitis
Vascular surgery @ Tallaght
Is it Charcot?
• Xray – normal
• MRI
• Antibiotics ↓
Vascular surgery @ Tallaght
What to do?
Structural &
neuropathy
Vascular surgery @ Tallaght
Neuropathic ulcer
Structural &
neuropathy
Offload
Lewis J et al. Cochrane Database Syst Rev. 2013
Vascular surgery @ Tallaght
Neuropathic ulcer
Vascular surgery @ Tallaght
What to do?
Structural &
neuropathy
Offload
Ischaemia
Osteomyelitis
Acute Charcot
Vascular surgery @ Tallaght
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
Malhotra et al Diabet Foot Ankle. 2014
Vascular surgery @ Tallaght
Osteomelitis - surgery
• Antibiotics
• Sliding scale
• Surgical
Debridement – all
infected bone
• Drainage
Vascular surgery @ Tallaght
Infection
• Multiple
procedures
• VAC closure
• Offloading
Vascular surgery @ Tallaght
What to do?
Structural &
neuropathy
Offload
Ischaemia
Osteomyelitis
Drain,
debride, ABx
Acute Charcot
Vascular surgery @ Tallaght
Acute Charcot
• Offload
• Non-wt bearing
• Assess stability
clinical & Xray
• Wait
• 9-12 months
Vascular surgery @ Tallaght
What to do?
Structural &
neuropathy
Offload
IschaemiaOsteomyelitis
Drain,
debride, ABx
Acute Charcot
Offload
Vascular surgery @ Tallaght
Vascular Intervention
Ischaemia
Revascularisation
Vascular surgery @ Tallaght
Imaging
• Popliteal pulse
– Angio
• Femoral pulse
– Duplex
• ? Femoral pulse
– CT
Popposelli F. JVS 2010
Vascular surgery @ Tallaght
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
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
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)
Su
rviv
al a
s a
pe
rce
nta
ge
Pedal Bypass surgery
Good et al Ir J Med Sci 2010
Vascular surgery @ Tallaght
Options
Vascular surgery @ Tallaght
Technical considerations
• Consent
• Ipsilateral
(antegrade)
• Local
• ? 4/5Fr
• ? ultrasound
Vascular surgery @ Tallaght
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
Vascular surgery @ Tallaght
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
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
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.
Vascular surgery @ Tallaght
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
Vascular surgery @ Tallaght
The evidence?
Vascular surgery @ Tallaght
Multidisciplinary care
Nason et al. Ir J Med Sci 2013
Vascular surgery @ Tallaght
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