Vascular ultrasound as diagnostic modalities for PAD MILENA Staneva

Noninvasive Ultrasound Tests Hand-held Doppler Resting Ankle-Brachial Index (ABI) Exercise ABI Non-invasive Vascular Laboratory Doppler waveform analysis Color Duplex Ultrasound These traditional tests continue to provide a simple, risk-free, and cost-effective approach to establishing the PAD diagnosis as well as to follow PAD status after procedures .

Ankle-Brachial Index (ABI) screening to detect PAD in the individual patient An ABI should be measured in: Age less than 50 years with diabetes, and one additional risk factor (e.g., smoking, dyslipidemia, hypertension, or hyperhomocysteinemia) Age 50 to 69 years and history of smoking or diabetes Age 70 years and older Leg symptoms with exertion (suggestive of claudication) or ischemic rest pain Abnormal lower extremity pulse examination Known atherosclerotic coronary, carotid, or renal artery disease

Resting Ankle-Brachial Index (ABI) ABI has been found to be 95% sensitive and 99% specific for angiographically diagnosed PAD. ABI Interpretation 0.90–1.20 Normal 0.70–0.89 Mild 0.40–0.69 Moderate 0.40 Severe >1.40 Noncompressible vessels Measurement of the ABI Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC II) J. vasc surg,2007, Vol.(45),1,S5

ABI Limitations Possible false negatives in patients with noncompressible arteries, such as some diabetics, renal insufficiency and elderly individuals. ABI > 1.40 - the tibial vessels at the ankle become non-compressible. Not well correlated with functional ability and should be considered in conjunction with activity history or questionnaires Insensitive to very mild occlusive disease and iliac occlusive disease Normal values ​​at rest in symptomatic patients may become abnormal after exercise

Toe-Brachial Index (ТВI) TBI values ​​remain accurate when ABI values ​​are not possible because of uncompressed tap ripple TBI is calculated by dividing the pressure of the fingers on the higher of the brachial pressures. TBI values ​​≤ 0.7 are generally considered to diagnose PAD in the lower extremities.

Exercise ABI Confirms the PAD diagnosis Assesses the functional severity of claudication May “unmask” PAD when resting the ABI is normal

Doppler waveform analysis Alternative test useful to unmask PAD when ABI >1.40 Disease progression – distal flow Norm –Triphasic  Biphasic  Моnophasic  Absent After mild – moderate stenosis Delayed acceleration, decreased systolic peak, increase of flow in diastole After setere stenosis, thrombosis Delayed acceleration, decreased systolic peak, increase of flow in diastole Thrombosis Consists of forward flow in systolic peak, reversal of flow in early diastole , forward flow in late diastole

Duplex Ultrasound Available for the screening and diagnosis of vascular lesions Provides extensive information on both arterial anatomy and blood flow DUS provides important information on haemodynamics. DUS sensitivity at 85–90% and specificity 95% to detect 50% diameter angiographic stenosis The decision to image is a decision to intervene if a suitable lesion is identified and is only applicable to a minority of patients with intermittent claudication, and then only after risk factors have been addressed and medical management followed. There is also a role for imaging in the small group of patients in whom there is a discrepancy between the history and objective clinical signs. The purpose of imaging is to assess the anatomical location, morphology and extent of disease in order to determine suitability for intervention and occasionally to differentiate atherosclerotic PAD from other causes such as neurogenic claudication and entrapment.

Duplex Ultrasound Technical advances in ultrasonography have allowed reproducible measurements of blood vessels and blood flow as well as standardization of criteria for assessment of PAD. Combined with the ABI, DUS provides all the information necessary for management decisions in the majority of patients with PAD, confirms the diagnosis, and provides information on lesion location and severity Peripheral artery wave forms: arterial form is triphasic – consists of forward flow in systolic peak, reversal of flow in early diastole and forward flow in late diastole. This becomes impaired (eliminated reverse flow due to stenosis of vessel and becomes biphasic  decreased systolic peak and increase of flow in diastole) The decision to image is a decision to intervene if a suitable lesion is identified and is only applicable to a minority of patients with intermittent claudication, and then only after risk factors have been addressed and medical management followed. There is also a role for imaging in the small group of patients in whom there is a discrepancy between the history and objective clinical signs. The purpose of imaging is to assess the anatomical location, morphology and extent of disease in order to determine suitability for intervention and occasionally to differentiate atherosclerotic PAD from other causes such as neurogenic claudication and entrapment.

Duplex Ultrasound Representative normal diameter and PSVs in lower limb arteries Artery Diameter ± SD (cm) PSV (cm/s) Aorta 1.70 ± 0.30 75 Common iliac artery 0.91 ± 0.13 110 External iliac artery 0.79 ± 0.13 Common femoral artery 0.80 ± 0.14 90 Superficial femoral artery (proximal) 0.60 ± 0.12 Superficial femoral artery (distal) 0.54 ± 0.11 Poplitel artery 0.52 ± 0.11 60 Peripheral artery wave forms: arterial form is triphasic – consists of forward flow in systolic peak, reversal of flow in early diastole and forward flow in late diastole. This becomes impaired (eliminated reverse flow due to stenosis of vessel and becomes biphasic  decreased systolic peak and increase of flow in diastole) The decision to image is a decision to intervene if a suitable lesion is identified and is only applicable to a minority of patients with intermittent claudication, and then only after risk factors have been addressed and medical management followed. There is also a role for imaging in the small group of patients in whom there is a discrepancy between the history and objective clinical signs. The purpose of imaging is to assess the anatomical location, morphology and extent of disease in order to determine suitability for intervention and occasionally to differentiate atherosclerotic PAD from other causes such as neurogenic claudication and entrapment. Norm femoral bifurcation

Duplex Ultrasound Excellent tolerance and lack of radiation exposure make DUS the method of choice for routine follow-up. DUS is also highly useful for the follow-up after angioplasty or to monitor bypass grafts Minimum surveillance intervals are approximately 3rd, 6th and 12th months, and then yearly after graft placement However, the data that might support use of duplex ultrasound to assess long-term patency of PTA is not robust. Peripheral artery wave forms: arterial form is triphasic – consists of forward flow in systolic peak, reversal of flow in early diastole and forward flow in late diastole. This becomes impaired (eliminated reverse flow due to stenosis of vessel and becomes biphasic  decreased systolic peak and increase of flow in diastole) The decision to image is a decision to intervene if a suitable lesion is identified and is only applicable to a minority of patients with intermittent claudication, and then only after risk factors have been addressed and medical management followed. There is also a role for imaging in the small group of patients in whom there is a discrepancy between the history and objective clinical signs. The purpose of imaging is to assess the anatomical location, morphology and extent of disease in order to determine suitability for intervention and occasionally to differentiate atherosclerotic PAD from other causes such as neurogenic claudication and entrapment.

Duplex Ultrasound Stent in CIA/EIA stent Collateral artery of the thigh in thrombosis a.femoralis stent

Duplex Ultrasound Vascular ultrasound is a simple and reliable technique to assess AAA B-mode of AAA in longitudinal showing : diameter of the neck, maximum anteroposterior diameter, residual lumen diameter, aneurysm length distal aortic diameter Peripheral artery wave forms: arterial form is triphasic – consists of forward flow in systolic peak, reversal of flow in early diastole and forward flow in late diastole. This becomes impaired (eliminated reverse flow due to stenosis of vessel and becomes biphasic  decreased systolic peak and increase of flow in diastole) The decision to image is a decision to intervene if a suitable lesion is identified and is only applicable to a minority of patients with intermittent claudication, and then only after risk factors have been addressed and medical management followed. There is also a role for imaging in the small group of patients in whom there is a discrepancy between the history and objective clinical signs. The purpose of imaging is to assess the anatomical location, morphology and extent of disease in order to determine suitability for intervention and occasionally to differentiate atherosclerotic PAD from other causes such as neurogenic claudication and entrapment.

Duplex Ultrasound Criteria for diagnosing occlusive disease These have been defined by comparing: maximum peak systolic velocity (PSV) end diastolic velocity (EDV) ratio of PSV at and just proximal to a stenosis (V2/Vl) waveform analysis with DUS Tabl. Criteria to define lower limb arterial stenoses* Peripheral artery wave forms: arterial form is triphasic – consists of forward flow in systolic peak, reversal of flow in early diastole and forward flow in late diastole. This becomes impaired (eliminated reverse flow due to stenosis of vessel and becomes biphasic  decreased systolic peak and increase of flow in diastole) The decision to image is a decision to intervene if a suitable lesion is identified and is only applicable to a minority of patients with intermittent claudication, and then only after risk factors have been addressed and medical management followed. There is also a role for imaging in the small group of patients in whom there is a discrepancy between the history and objective clinical signs. The purpose of imaging is to assess the anatomical location, morphology and extent of disease in order to determine suitability for intervention and occasionally to differentiate atherosclerotic PAD from other causes such as neurogenic claudication and entrapment. Stenosis (%) PSV (cm/s) V2/Vl ratio 30–50 150–200 1.5–2 50–75 200–400 2–4 > 75 > 400 > 4 *Cossman DV, Ellison JE, Wagner WH et al. Journal of Vascular Surgery 1989;10:522

Duplex Ultrasound Before stenosis – norm - thriphasic High-grade stenosis - monophasic PSV > 600 cm/s EDV> 100 cm/s V2/Vl = 6 Peripheral artery wave forms: arterial form is triphasic – consists of forward flow in systolic peak, reversal of flow in early diastole and forward flow in late diastole. This becomes impaired (eliminated reverse flow due to stenosis of vessel and becomes biphasic  decreased systolic peak and increase of flow in diastole) The decision to image is a decision to intervene if a suitable lesion is identified and is only applicable to a minority of patients with intermittent claudication, and then only after risk factors have been addressed and medical management followed. There is also a role for imaging in the small group of patients in whom there is a discrepancy between the history and objective clinical signs. The purpose of imaging is to assess the anatomical location, morphology and extent of disease in order to determine suitability for intervention and occasionally to differentiate atherosclerotic PAD from other causes such as neurogenic claudication and entrapment. After stenosis - monophasic Delayed acceleration, decreased systolic peak and increase of flow in diastole

Duplex Ultrasound Instent restenosis in FSA stent After stenosis Collateral artery of the thigh in thrombosis a.femoralis stent After stenosis Instent restenosis in FSA

Duplex Ultrasound Bypass graft stenosis Criteria: PSV >350 cm/s or < 45 cm/s V2/Vl - >1.5 to > 3.0. waveform analysis with DUS - monophasic in the graft or inflow arteries indirectly predict graft stenosis Peripheral artery wave forms: arterial form is triphasic – consists of forward flow in systolic peak, reversal of flow in early diastole and forward flow in late diastole. This becomes impaired (eliminated reverse flow due to stenosis of vessel and becomes biphasic  decreased systolic peak and increase of flow in diastole) The decision to image is a decision to intervene if a suitable lesion is identified and is only applicable to a minority of patients with intermittent claudication, and then only after risk factors have been addressed and medical management followed. There is also a role for imaging in the small group of patients in whom there is a discrepancy between the history and objective clinical signs. The purpose of imaging is to assess the anatomical location, morphology and extent of disease in order to determine suitability for intervention and occasionally to differentiate atherosclerotic PAD from other causes such as neurogenic claudication and entrapment.

Duplex Ultrasound Thrombosed bypass with prosthesis Collateral artery of the thigh in thrombosis a.femoralis Thrombosed bypass with prosthesis Accessible bypass with prosthesis

Duplex Ultrasound Lower limb arterial occlusion Occlusion is diagnosed with confidence if there is: no colour Doppler or spectral signal in the occluded segment a high-resistance spectral signal above the segment a low-amplitude spectral signal below the segment a collateral leaving the artery at the top end a collateral re-entering the artery at the lower end. Peripheral artery wave forms: arterial form is triphasic – consists of forward flow in systolic peak, reversal of flow in early diastole and forward flow in late diastole. This becomes impaired (eliminated reverse flow due to stenosis of vessel and becomes biphasic  decreased systolic peak and increase of flow in diastole) The decision to image is a decision to intervene if a suitable lesion is identified and is only applicable to a minority of patients with intermittent claudication, and then only after risk factors have been addressed and medical management followed. There is also a role for imaging in the small group of patients in whom there is a discrepancy between the history and objective clinical signs. The purpose of imaging is to assess the anatomical location, morphology and extent of disease in order to determine suitability for intervention and occasionally to differentiate atherosclerotic PAD from other causes such as neurogenic claudication and entrapment.

Duplex Ultrasound Collateral artery of the thigh in thrombosis a.femoralis Monophasic blood flow in tiabial artery as a result of thrombosis in femoral artery Collateral artery of the calf as a result of thrombosis in femoral artery

Duplex Ultrasound Limitations Pitfalls of DUS are related mainly to difficulties in assessing the lumen in highly calcified arteries. Insonation in the area of open ulcers or excessive scarring may not be possible. Also in some cases (e.g. obesity, gas interpositions), the iliac arteries are more difficult to visualize and alternative methods should be considered when the imaging is suboptimal. Peripheral artery wave forms: arterial form is triphasic – consists of forward flow in systolic peak, reversal of flow in early diastole and forward flow in late diastole. This becomes impaired (eliminated reverse flow due to stenosis of vessel and becomes biphasic  decreased systolic peak and increase of flow in diastole) The decision to image is a decision to intervene if a suitable lesion is identified and is only applicable to a minority of patients with intermittent claudication, and then only after risk factors have been addressed and medical management followed. There is also a role for imaging in the small group of patients in whom there is a discrepancy between the history and objective clinical signs. The purpose of imaging is to assess the anatomical location, morphology and extent of disease in order to determine suitability for intervention and occasionally to differentiate atherosclerotic PAD from other causes such as neurogenic claudication and entrapment.

Conclusion PAD is a common atherosclerotic disease associated with risk of cardiovascular ischemic events and significant functional disability PAD can be effectively assessed in the primary care The ankle brachial index and Duplex Ultrasound are an effective and efficient methods for diagnosis of PAD and the follow-up Early detection of PAD allows for appropriate disease management and decreased likelihood of ischemic events and disease progression

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