Interpretation of peripheral waveforms (Part I)

Arterial major descriptors

flow direction, phasicity, resistance

Flow direction

antegrade, retrograde, bidirectional, absent

Phasicity

multiphasic, monophasic

Resistance

high, intermediate, low

Additional modifier terms

Upstroke, sharp peak, spectral broadening, staccato, dampened, flow reversal

Antegrade

blood flows in the normal direction for the artery being evaluated

Retrograde

blood flows opposite to the normal direction for the artery being evaluated

Bidirectional

blood flow enters and leaves a contained space via the same orifice

Absent

no blood flow is detected with an absent spectral doppler signal

Multiphasic

Waveform crosses the zero-flow baseline and contains both forward and reverse velocity components

Monophasic

waveform does not cross the zero-flow baseline throughout any part of the cardiac cycles, blood flows in a single direction

High resistance key features

Sharp upstroke, brisk downstroke, with or without diastolic flow reversal

Intermediate resistance key features

sharp upstroke, brisk downstrokes, visible presence of an end-diastolic notch and continuous forward flow throughout diastole that is above the zero-flow baseline

An intermediate resistance waveform suggests

vasodilation

Low resistive key features

prolonged downstroke in late systole and continuous forward flow throughout diastole

Rapid upstroke

Nearly vertical slope or steep rise to peak systole

Prolonged upstroke

Abnormally gradual slope to peak systole

Sharp peak

sharp, single, and well-defined peak, often with maximum velocity, within range of the artery being interrogated

Spectral broadening

widening of the velocity band in the spectral waveform, a “filling in” of the spectral window under the systolic peak

Staccato

A very high-resistance pattern with a short spike of velocity acceleration and deceleration followed by a short and low-amplitude diastolic signal reflecting low antegrade flow

Dampened

Combined finding of an abnormal upstroke and peak, often with decreased velocity

Flow reversal

Flow that changes direction, not as part of normal diastolic flow reversal, which may be transient or consistent with each cardiac cycle

Normal resting inflow arteries (lower)

common, external, and internal iliac artery

Normal resting inflow arteries (upper)

innominate and subclavian artery

Normal resting outflow arteries (lower)

common femoral, deep femoral, superficial femoral, and popliteal artery

Normal resting outflow arteries (upper)

axillary and brachial artery

Normal resting run-off arteries (lower)

anterior tibial, posterior tibial, peroneal artery

Normal resting run-off arteries (upper)

radial, ulnar

Normal resting plantar, palmar, and digital arteries

Flow remains laminar

Normal peripheral arterial waveforms following exercise or resulting from increased body temperature

Increased flow demand and decreased vascular resistance associated with exercising; PSV can increase significantly

Normal CCA

minimal or no reversed flow and relatively high diastolic flow from the more pronounced effect of the low-resistance ICA

Normal ECA

presence of reverse flow phase in late systole or early diastole and a multiphasic flow pattern are characteristics of an artery supplying a high-resistance vascular bed

Normal proximal ICA

With flow separation along the outer wall, bulb; with forward flow along the flow divider

Normal mid ICA

forward flow throughout the cardiac cycle and relatively high diastolic flow velocities are characteristics of an artery perfusing a low-resistance vascular bed

Normal distal ICA

Foward flow throughout the cardiac cycle and relatively high diastolic flow velocities are noted. There may be an increase in PSV relative to the proximal and mid segments of the ICA

Normal vertebral artery

Forward flow throughout the cardiac cycle and relatively high diastolic flow velocities are noted. The flow pattern is similar to that of the ICA

Normal celiac

Constant forward flow throughout systole and diastole, antegrade, low resistive, and monophasic

Normal SMA (fasting)

Waveform is antegrade, high resistance, and multiphasic, with early diastolic flow reversal

Normal SMA (postprandial)

Velocity increases in both systole and diastole. Antegrade but low resistance and monophasic

Normal renal artery

Flow in the normal main and/ or accessory renal artery is antegrade, low resistive, and monophasic

Low-resistance arteries (Normal RI= 0.55-0.7)

Internal carotid arteries

Hepatic arteries

Renal arteries

Testicular arteries

High resistance arteries (Normal RI >0.7)

ECA

Extremity arteries

Fasting SMA and IMA

Artificial causes of spectral broadening

Large sample volume

High gain

Physiologic causes of spectral broadening

Normal small vessels

Normal turbulence

Pathologic causes of spectral broadening

Compressed vessels

Turbulent flow