Imaging for Peripheral Vascular Disease

Transcription

1 Imaging for Peripheral Vascular Disease James G. Jollis, MD Director, Rex Hospital Cardiovascular Imaging

2 Imaging for Peripheral Vascular Disease 54 year old male with exertional calf pain in his right upper calf, relieved with rest. Would you obtain an ABI? 1. Yes, routinely 2. Yes, occasionally 3. No

3 Imaging for Peripheral Vascular Disease 54 year old male with exertional calf pain in his right upper calf, relieved with rest. Where is stenosis? 1. Aorta 2. Iliac artery 3. Femoral artery 4. Popliteal artery

4 Imaging for Peripheral Vascular Disease Clinical presentation of PVD Imaging for PVD ABI Duplex US MR CT DSA Imaging strategy

5 Risk Factors for PVD: Framingham Heart Study Smoking Reduced Increased Diabetes Hypertension Hypercholesterolemia Age (per 10 years) Relative Risk

6 Groups at risk for lower extremity PAD Age 70 years. Age 50 to 69 years with a history of smoking or diabetes. Age 40 to 49 with diabetes and at least one other risk factor for atherosclerosis. Leg symptoms suggestive of claudication with exertion or ischemic pain at rest. Abnormal lower extremity pulse examination. Known atherosclerosis at other sites (eg coronary Known atherosclerosis at other sites (eg, coronary, carotid, or renal artery disease).

7 Clinical Presentation Asymptomatic 20-50% Atypical leg pain 40-50% Classic claudication 10-35% Exertional calf pain that does not begin at rest, causes the patient to stop walking, and resolves within 10 minutes of rest Critical limb ischemia 1-2 %

8 Clinical Presentation Asymptomatic 20-50% Atypical leg pain 40-50% Classic claudication 10-35% Exertional calf pain that does not begin at rest, causes the patient to stop walking, and resolves within 10 minutes of rest Critical limb ischemia 1-2 %

9 Differential Diagnosis of Intermittent Claudication Quality of pain Onset Relieved by Location Legs affected Intermittent Venous Neurogenic Claudication Claudication Claudication Cramping Gradual, consistent Standing still Muscle groups (buttock, thigh, calf) Usually one "Bursting" Gradual, can be immediate Elevation of leg Whole leg Usually one Electric shock-like Can be immediate, inconsistent Sitting down, bending forward Poorly localized, can affect whole leg Often both

10 Imaging for Peripheral Vascular Disease Clinical presentation of PVD Imaging for PVD ABI Duplex US MR CT DSA Imaging strategy

11 Buttock & Hip Claudication ±Impotence Leriche s Syndrome Thigh Claudication Upper 2/3 Calf Claudication Lower 1/3 Calf Claudication Foot Claudication

12 DDx of Leg Pain 1. Vascular a) DVT (as for risk factors) b) PVD (claudication) 2. Neurospinal a) Disc Disease b) Spinal Stenosis (Pseudoclaudication) 3. Neuropathic a) Diabetes b) Chronic EtOH abuse 4. Musculoskeletal a) OA (variation with weather + time of day) b) Chronic compartment syndrome

13 Imaging for Peripheral Vascular Disease Non-invasive techniques ABI (Ankle/Brachial Index) Exercise Test Segmental Pressures Segmental Volume Plethysmography Duplex Ultrasonography CT Angiogram MRA (Magnetic Resonance Arteriography) Carotid Doppler identifies patients who are at risk for stroke Vascular ultrasound Invasive techniques Peripheral Angiograms CT Angiograms MR Angiograms g

14 Ankle-Brachial Index 0.91 to 1.30 Normal 0.90 At Arterial obstruction ti 0.40 Severe obstruction >1.3 Suggests noncompressible vessels Consider toe brachial index (Normal >0.7, Rest pain <0.2) For patients with a normal ABI and claudication symptoms, obtain exercise ABI

15 Ankle-Brachial Index Blood-flow waveform analysis Normal Triphasic Moderate Loss of reverse flow component Blunted amplitude Severe Sluggish monophasic

16 Ankle-Brachial Index Segmental recordings 20 mm Hg drop between segments implies a significant stenosis

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18 Ankle-Brachial Index Medicare reimbursement Include Wave-form analysis Indication Claudication, pain / absent pulses, ulcer/gangrene, thromboembolism, b aneurism.

19 Imaging for Peripheral Vascular Disease Clinical presentation of PVD Imaging for PVD ABI Duplex US MR CT DSA Imaging strategy

20 Duplex Ultrasonography Duplex Combination of 2 D and Doppler ultrasound Anatomic information Vessel wall, intraluminal obstructive lesions, perivascular compressive structures Hemodynamic information Ratio Peak Systolic velocity Stenosis Stenosis versus normal segment % % >= 4.0 >= 75%

21 Duplex Ultrasonography Proximal to stenosis

22 Duplex Ultrasonography Stenosis

23 Duplex Ultrasonography Occluded stent

24 Imaging for Peripheral Vascular Disease Clinical presentation of PVD Imaging for PVD ABI Duplex US MR CT DSA Imaging strategy

25 Magnetic resonance imaging Technique 3D gradient echo Gadolinium Enhanced cc Automated Scan delay Renal arteries to toes Limitations Uncooperative patient Claustrophobia Metal artifact Stepping table or bolus chase Pacemakers/ICDs 45-min exam Lack of visualization of calcium

26 Computed tomography Technique Multidetector CT scanner 64 + Slice Iodinated contrast volume similar to conventional angiography cc Automated Scan Delay Limitations Radiation Calcium Can see within stents Contrast nephropathy Renal arteries to ankles 20-minute exam High powered post processing software crucial

27 Imaging for Peripheral Vascular Disease 1. Clinical presentation of PVD 2. Imaging for PVD 1. ABI 2. Duplex US 3. MR 4. CT 5. DSA

28 Digital Subtraction Angiography Subtract a 'pre- contrast image' or the mask from later images

29 54 year old man with upper right leg claudication MR vs DSA Right common iliac artery stenosis

30 54 year old man with upper right leg claudication MR vs DSA Right superficial femoral artery stenosis

31 Modality comparison STRENGTHS Digital Stents well visualized Radiation subtraction angiography WEAKNESSES Contrast nephropathy 2D Computed 3D Radiation tomography Contrast nephropathy Blooming artifact with calcium Stents poorly visualized Magnetic resonance Duplex ultrasound 3D No radiation Hemodynamic information Stents can be assessed No radiation or contrast Lower resolution than CT or DSA Gadolinium - Nephrogenic systemic fibrosis (NSF) Stents t artifact t except nitinol Operator dependent and time consuming to image both lower extremities Calcified segments difficult to assess

32 Imaging for Peripheral Vascular Disease Clinical presentation of PVD Imaging for PVD ABI Duplex US MR CT DSA Imaging strategy

33 Vascular Screening Recommendations ABI Screening TASC II : ADA Consensus Panel : All patients who have Patients over the age of exertional leg symptoms 50 years who have All patients between the diabetes age of and who Patients with diabetes have a cardiovascular risk younger than 50 years of factor age who have other PAD risk factors (i.e. smoking, All patients age greater hypertension, than 70 years regardless hyperlipidemia, diabetes of risk factor status more than 10 years) All patients with a ABI should be repeated in 5 Framingham risk score of years if normal 10%-20% *Trans-Atlantic Inter-Society Consensus Document on Management of Peripheral Arterial Disease (TASC)

34 Algorithm for vascular testing for possible claudication Symptoms - claudication Measure ABI ABI <= 90 ABI ABI > 1.3 Consider consult with vascualar specialist Imaging Duplex / CTA / MR / Angio Exercise testingti Abnormal Toe brachial index Normal >0.7, Rest pain <0.2 Normal or unchanged

35 Imaging for Peripheral Vascular Disease Conclusions Cigarette smoking, diabetes, and older age are primary risk factors for PVD PVD clinical manifestations include none, typical claudication, leg pain, and gangreneg

36 Imaging for Peripheral Vascular Disease Conclusions ABI testing represents a helpful initial test of lower extremity arterial perfusion If the ABI is abnormal, consider other imaging g to diagnose PVD