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Using the Vascular Laboratory to Guide Revascularization in CLIGregory J. Landry, MD
Associate Professor of Surgery
No disclosures
Vascular Lab and CLI
• Duplex is useful for planning interventions– Arterial anatomy– Venous conduit
• Assessment of arterial perfusion to foot– Plethysmography– Laser Doppler– TcPO2
CFA
Mid PT
Mid PeronealProximal SFA
Mid Popliteal
Mid AT
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Popliteal occlusion
Pre occlusive external iliac
High-grade SFA stenosis
Arterial Map
Duplex Mapping
• 150 elective vascular surgery patients• Duplex (aorta to ankle) and angiography• Sensitivity, specificity and predictive
values of duplex in detecting stenoses and occlusions
Moneta, JVS, 1992
Duplex Mapping: Criteria for Stenosis(Suprageniculate Arteries)
• Distinguish <50% vs. >50% stenosis-100% increase in peak systolic velocity-loss of end systolic reverse flow-PSV > 200cm/s for iliac arteries
• Occlusion-No color filling-No signal with pulseoppler
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Duplex Mapping: Criteria for Patency(Tibial Arteries)
• Visualization by color flow
• Pulsatile flow by Doppler
• Segmental interruption in flow from knee to ankle
Duplex Mapping
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1516
41
no disease
aortoiliac
multilevel
fem/pop/tib
• % angio visualized segments seen by duplex– CIA 95– EIA 98– CFA 100– PFA 100– SFA 100– Popliteal 99– AT 94– PT 96– Peroneal 83
Duplex Mapping: detection of suprageniculatestenosis; infrageniculate interruption of flow
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Iliac CFA PFA SFA Pop AT PT Per
Sens
SpecPPV
Duplex Mapping: Detection of Occlusion
• Duplex detected occlusion– 252 segments (43 iliac, 176 SFA, 33 pop)
• In 98% of comparisons duplex successfully distinguished stenosis from occlusion
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Duplex Mapping: Velocity Ratios
Angiography Diameter Reduction
PSV ratio 0-49% 50-74% 75-99% 100%
<2.5 209 8 0 0
2.5 - <5.5 8 15 9 0
≥5.5 or EDV ≥ 0.6m/s
0 2 12 0
No Doppler signal 0 0 0 7
Kappa = 0.70
Legemate, Br J Surg, 1991Eiberg, Eur J Vasc Endovasc Surg, 2002
Duplex vs Segmental Pressures
• 4 cuff segmental pressures– High thigh– Above knee– Below knee– ankle
Duplex vs. Segmental Pressures
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EIA/CFA SFA Pop
Sens-Dup
Sens- SPMSpec-DupSpec-SPM
p < 0.001
Moneta, JVS, 1993
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Duplex vs. Segmental Pressures
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0%
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100%
Duplex SegmentalPressures
Complete agreement of duplex and segmental pressures with angio
p < 0.0001
Sudden Onset left lower leg and foot pain
Right Leg Claudication Left Foot Rest Pain
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Left foot ulceration Left foot ulceration
Microcirculation Measurement of CLI
• Many factors influence wound healing aside from circulation– Location, size and depth of wound– Infection– Systemic illness (diabetes, CHF)– Immunosuppression– Socioeconomic factors
• Clinical judgement trumps the vascular lab
Toe plethysmography/pressures
• Usually more reliable in patients with noncompressible ABI
• <30mm Hg consistent with CLI
• Not accurate in thickly callused toes
• Can’t always be measured in the presence of gangrene/ulcers
• Medial calcinosis in toes
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TcPO2
• measurement of the partial pressure of oxygen on the skin surface
• < 30 mm Hg predicts less likelihood of wound healing
• Long exam time • Influenced by skin
temperature
Skin Perfusion Pressure
Castronuovo, JVS, 1997Kawarada, Cath Cardio Intervent, 2011
Skin Perfusion Pressure
Sensitivity Specificity
SPP 72% 88%
ABP 74% 70%
TBP 63% 90%
TcPO2 60% 87%
Yamada, JVS, 2008
Duplex Mapping and CLI: Conclusions
• Duplex Mapping– Highly accurate– Better than segmental pressures and
ABI– Clinically useful in patients with critical
limb ischemia as a planning modality for potential reconstruction.
– Supplement with vein mapping for planning.
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Evaluation of Foot Perfusion
• Wound heterogeneity makes evaluation difficult, clinical judgement still important
• ABI, TBI, TcPO2, SPP all useful with SPP having the best combination of sensitivity and specificity