Annals of the Royal College ofSurgeons of England (1986) vol. 68
Doppier waveform analysis in the management
of lower limb arterial disease
W BRUCE CAMPBELL MS FRCS*
Research Fellow and Honorary Senior Registrar Bristol Royal Infirmary
Key words: ARTE.RIIES; ARTLRIR()S(CI.IR,RoSIS; I)IAGNOSIS, (:ONPJTEIR ASSISTEA): UILTRASONI(:S; \V\S(UJILAR D)ISlASIA
Arterial disease changes the shape ofDoppler ultrasound waveforms
recorded noninvasivelyfrom arteries in the lower limbs. These changes
can be described numerically by computer analysis ofwaveforms, and
techniques currently in use are pulsatility index, Laplace transform
and principal component analysis.
These waveform analysis methods allow assessment of aortoiliac
disease from Doppler recordings at the femoral artery. In addition,
thefemorodistal segment can be evaluated by comparingfemoral and
distal waveforms, even in the presence of more proximal arterial
disease. Other possible applications for waveform analysis include
noninvasivefollow-up ofangioplasty or bypass grafts and the detec-
tion ofearly, presymptomatic arterial disease. Experience in recording
Doppler waveforms is important if variability is to be minimised.
Currently, these methods allow exclusion ofaortoiliac disease prior
tofemorodistal grafting but their other potential roles requirefurther
In 1959 Satomura described the use of a Doppler ultra-
sound probe for detecting blood flow signals from arteries
(1) and suggested that this technique might be used in the
diagnosis of atherosclerosis. During the 1960's the applica-
tions of the Doppler ultrasound probe in vascular practice
were more clearly defined, in particular, confirmation of
vessel or graft patency and the measurement of lower limb
systolic pressure (2). All these could be achieved simply by
listening to the sound generated by the Doppler system.
However, records ofwaveform shape also became available
and directional systems were developed which could sepa-
rate forward and reverse flow during the various phases of
the cardiac cycle (3) (Fig. la).
It was observed that arterial disease resulted in charac-
teristic changes in the shape of the Doppler waveform,
which could be recognised by simple inspection of the trace
(4) and described, to some extent, by reference to specific
waveform features; loss of the early diastolic reverse flow of
amplitude etc. (Fig. lb & c). These changes can be used to
diagnose disease in vessels proximal to the site of recording
either by simple observation (5) or by measurement of
specific parameters from the waveform (6).
Recognition of progressive changes in ultrasound wave-
form shape invited development of an objective method by
which they could be measured. The first objective techni-
que of waveform analysis was described by Gosling and his
colleagues who devised a parameter called pulsatility index
*Present Appointment and correspondence to: Clinical Lecturer
in Surgery, Nuffield Department of Surgery, John Radcliffe
Hospital, Oxford OX3 9DU
(PI) which was obtained by dividing the maximum vertical
excursion of the waveform by the mean value throughout
the cardiac cycle. The value of PI was demonstrated to fall
1 The shape of Doppler arterial waveforms in health and
disease. Doppler shift frequency is on the vertical axis (pro-
portional to blood velocity), and time is on the horizontal axis.
(a) shows a normal waveform, with rapid systolic upslope and
downward slope. There is a phase of reverse flow in early
diastole, followed by a phase of forward diastolic flow.
(b) This waveform, distal to a severe stenosis shows prolongation
of the systolic downward slope with less marked prolongation
of the upslope of the wave. The early diastolic reverse flow has
been lost-this is a characteristic finding distal to a stenosis.
(c) This waveform, distal to a complete occlusion, is recorded at
higher gain than (a) or (b). Blood is bypassing the upstream
occlusion through collaterals and the wave is very damped.
Forward flow throughout diastolie may be seen in severely
ischaemic limbs with dilated peripheral vessels.