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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

0

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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

82

34

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