Arterial Physiologic Testing- Lower Extremities Chapter 11 Arterial Physiologic Testing- Lower Extremities

Arterial physiologic testing Purpose: Evidence for arterial occlusive disease? Responsible for the patient’s symptoms? Arterial disease and neurospinal compression, which condition is causing the symptoms? If disease is present, how severe? 14

Indications for Extremity Arterial Testing Claudication Ischemic Rest Pain Ulceration Gangrene F/Up for limb vascularization or intervention F/up Disease Progression (PVD) Suspected Aneurysm ASOD Asymptomatic Bruit Acute Arterial Occlusion Pre-Op radial harvest or hemodialysis access creation Raynaud’s TOS

Indications for Extremity Arterial Testing Claudication-primary symptom Muscle cramping, aching, or tiredness brought on by exercise and relieved quickly by rest Symptoms are reproducible Distance Severity Location

Indications for Extremity Arterial Testing Claudication The location of pain often correlates with a more proximal flow limiting stenosis Site of Pain Level of Disease Calf SFA and/or Pop Thigh Distal EIA; CFA Thigh or Buttock A/I; IIA Most common site of disease is the SFA

Indications for Extremity Arterial Testing Rest Pain End Stage Disease- sx of advances arterial insufficiency Decreased perfusion to the tissue causes constant burning or throbbing pain in the forefoot, heel, toes Relieved by dependency

Indications for Extremity Arterial Testing Chronic Critical Limb Ischemia Criteria >2 weeks of foot pain at rest Non-Healing wounds or gangrene of the foot or toes

Indications for Extremity Arterial Testing Necrosis; Tissue Loss End stage disease- death of the tissue Effects the tips of the toes and extends upward Severe pain – pre-gangreous state Intervention is necessary to prevent further destruction of the tissue and infection

Indications for Extremity Arterial Testing Gangrene- local death of body tissue Dry Gangrene- most common destruction of blood supply to tissue in pts with DM, ASOD, thrombosis, or trauma Moist- (odor) results from invasion of toxin- producing bacteria that destroys the tissue

Indications for Extremity Arterial Testing Gas Gangrene- results from invasion of wounds by anaerobic bacteria Gas forms under the skin and a watery exudates is produced Emergency treatment is needed with penicillin and anti toxins otherwise fatal

?? Symptoms Begin when the endothelial cells are damaged by RISK FACTORS and plaque begins to form in the arteries There is inadequate blood flow and oxygen to the tissue and muscle Arterial lumen is 50% diameter reduction or a 75% area reduction

Cross section view, plaque development Artery wall Atherosclerosis plaque Ultrasound color Doppler Ultrasound image plaque Normal artery residual lumen

Arterial occlusive disease Mild arterial disease Pt. Asymptomatic May have decreased pedal pulses With exercise a mild decrease in ankle pressure Moderate disease Asymptomatic at rest Intermittent claudication Significant decease in ankle pressure during and following exercise.

Arterial occlusive disease Severe disease Ischemic rest pain in feet and toes Non-healing wounds on feet/toes Ulceration Tissue necrosis, gangrene

Patient History Obtain a thorough History Important to understand that the majority of patients have co-existent Cardiac Disease and/or PVD The entire cardio-vascular system, including past surgeries and invasive procedures, reconstructive surgeries, amputations, as well as renal or transplant operations should be recorded

Patient History Document Pain (Location, Distance, Rest Time) Risk Factors (patient and family history) DM (insulin dependent?) Smoking (how long/how much) HTN- (controlled?) Hyperlipidemia Cardiac History (CAD,MI, A-Fib, Angina) TIA/CVA List Medications

Physical Exam What to look for & palpate. Cold foot (Polar) Pallor Dependent rubor Ulceration, gangrene, necrosis Trophic Changes Blue Toe Reduced pulses CFA, POP, PTA, DPA Rating 0-3

Arterial Pathology Thrombo-emboli Blue Toe Syndrome

Arterial Pathology Aneurysm AAA Popliteal

Arterial Extremity Testing Indirect Testing Methods: Pressure Assessment Plethysmography Continous Wave Doppler Exercise Stress Testing

1. Pressure Assessment: ABI and/or Segmental Pressures

Segmental Pressure Principle In a normal individual in a supine position, ankle systolic pressure is ≥ brachial pressure. Pt. should be in a basal state prior to pressure acquisition

Blood pressure cuff size: Bladder should be 20% wider than limb diameter Thigh = 12 x 54 cm Arms, Calf, Ankle = 10* or 12* x 40 cm Metatarsal (child-size) = 9 x 20 cm Digit = 2cm or 2.5 x 5 cm Non-uniform limb sizes = variations in pressures.

4 cuff technique

3 cuff technique A three cuff method may be used with a 19 x 40 cm or 17 cm cuff. Placement of a single thigh cuff replaces the two thigh cuffs in a four cuff method.

3 cuff versus 4 cuff 3 cuff method (17cm thigh cuff) if abnormal, cannot differentiate AI from SFA disease 4 cuff method (12 cm thigh cuffs) upper thigh cuff pressure artifact (≥ 20 mmHg) suppose to differentiate AI from SFA

Doppler Pressure Sites Dorsalis Pedis easily compressed harder to locate Posterior Tibial harder to compress easier to locate Essential not to drift off vessel !

Segmental Limb Pressures Sites Useful in identifying region(s) of disease Metatarsal and toe pressures often useful This study indicates probable inflow disease and femoro- popliteal disease in the left leg Note: the numerical value within the box is the actual pressure of the corresponding segment; the number outside of the box is an index that is automatically calculated by the machine

Segmental Limb Pressure compare to contralateral limb segment compare to adjacent ipsilateral segments compare to brachial pressure A 20 mmHg or greater pressure gradient (drop) is significant in the presence of an abnormal ABI

If thigh pressure (3 & 4 cuff) is normal = no significant inflow disease If upper thigh Pressure (4 cuff) or large thigh cuff Pressure (3 cuff) is abnormal, other methods are needed to differentiate AI from Femoral disease

Cuff pressures vary from intra-arterial pressures due to variations in limb girth Expect a “fudge factor” up to 20 mmHg.

The Ankle/Brachial Index (ABI) Highest ankle pressure divided by the higher brachial pressure Highest ankle pressure value is used for reported ABI 7

Resting (ABI) values >1.0 = Normal .9 – 1.0 = Usually normal Perform Exercise Stress Test if borderline and patient is symptomatic .8 - .9 = mild .4 - .8 = moderate .3 - .4 = severe .0 - .3 = rest pain; critical, impending tissue loss 20

Pressure limitation: calcified arteries diabetics chronic steroid therapy renal dialysis patients segmental pressures unobtainable or excessively high (ABI > 1.4) PTA

PPG pressure assessment

PPG Segmental Pressures + digital arteries rarely calcify + convenient + requires less skill - ambient light interference - no audible pulse - not good for severe disease - ulceration

Toe Pressures with PPG method

Toe Brachial Index (TBI) Digit vessels are not affected by calcific medial sclerosis Normal > 0.75 Abnormal < 0.66

Pressure advantages Quantitative information on limb perfusion Easy to perform Substantial clinical validation

2. Arterial Plethysmography Pneumoplethsmography Strain-gauge Impedance Photo electric

Arterial Plethysmography: The measurement of a volume change in a limb or organ Air (pneumo) plethysmography Pulse volume recording (PVRs) Photo-plethysmography (PPG) Infrared light transmitted into tissue Reflected light processed for cutaneous blood flow

Pulse Volume Recording (PVR) Limb volume changes w /systole Air is displaced within a cuff Instantaneous pressure change is recorded. PVR wave air cuff trans Limb air

Normal PVR Peak systole Reflected wave

PVR Waveforms Waveform morphology changes with disease severity MILD MODERATE

Pt. -- Jeff F. Rt ABI = 0 Lt ABI = 1.2 Rt Rt Thigh Lt Thigh Rt Above Knee Rt Below Knee Rt Ankle Rt Metatarsal Lt Thigh Lt Above Knee Lt Below Knee Lt Ankle Lt Metatarsal

Patrick, 59 year old male High thigh Above knee Below Knee Ankle Lt Thigh Rt Thigh RT ABI 1.21 LT ABI 0.0 Above knee Lt Above Knee Rt Above Knee Below Knee Ankle Lt Below Knee Rt Below Knee Rt Ankle Lt Ankle

Rt ABI 0.49 Lt ABI 0.53 Pt April. 46 yr old female R Brachial pressure 135 L Brachial Pressure 135 Pt April. 46 yr old female Hx of bilateral hip and buttock claudication

PVR Limitations Tremor - motion Dist. disease with prox. occlusion Subjective Atrial Fib.

PVR advantages easy to learn and to perform assessment of global limb perfusion metatarsal and toe evaluation not affected by calcified arteries

PPG waveforms for digit assessment index fingers Right Left