QVI Case of the
For past cases,
is a pleasant 88 year old female with a known 3.7
centimeters abdominal aortic aneurysm from duplex scanning
in 2005. She now presents with a one month history of
bilateral leg and foot pain and numbness with
discoloration of the toes. Therefore, she was referred
to us for a complete lower extremity evaluation including
physiologic studies with duplex imaging of the aorta, iliac
and infrainguinal vessels. She has bilateral edema with
a history of venous insufficiency with right leg vein
stripping done many years ago. She has a history of
hyperlipidemia, controlled hypertension, and currently
abuses tobacco. She denies any coronary artery disease but
does have a cardiac arrhythmia treated with a
and popliteal pulses are present bilaterally. The ankle pulses
are difficult to palpate probably secondary to the moderate
amount of edema at her ankles. Her toes are bluish throughout
bilaterally as well as her metatarsal foot area.
Bilateral brachial blood pressure was 146 mm/Hg on the right
and 140mm/Hg on the left by Doppler.
Physiologic testing: Pulse
volume recordings (PVR’s) were performed at the high thigh,
above the knee, below the knee and ankle level. PVR waveforms
were essentially normal and equal bilaterally consistent with
normal arterial flow in the lower extremities.
Resting ankle brachial index’s (ABI’s) were normal at 1.07 in
the DPA and 1.12 in the PTA on the right and 1.08 in the DPA
and 1.11 in the PTA on the left. Due to her physical exam and
symptoms, toe photoplethysmography (PPG) waveforms were
obtained and noted to be flat consistent with little or no
perfusion to the digits.
studies showing essentially normal pulse volume waveforms but
flat great toe PPG
Ultrasound Findings: The aorta
and iliac arteries were imaged from the suprarenal aorta to the
inguinal ligament. T
he abdominal aorta is notably large and ectatic
throughout. The suprarenal aorta measuring 2.5 cm and the
mid aorta measuring 2.7 cm with the presence of distal
infrarenal aneurysm measuring 5.4cm AP x 5.3 cm transverse.
amount of thrombus is appreciated within the aneurysm sac.
Color flow Doppler and spectral analysis was performed and
revealed normal flow patterns throughout the aorta and iliac
arteries with no evidence of significant or flow limiting
infrainguinal arteries were then imaged from the groin to
the ankles. Only minor wall irregularity and calcification
was demonstrated with no flow limiting stenosis detected.
Color flow Doppler and spectral analysis revealed normal
flow patterns and velocities throughout.
Figure 1 - Longitudinal
image of the proximal aorta showing the variable diameter of
2 - Longitudinal
image of the distal aorta showing the
Figure 3 - Transverse (cross sectional) im
age of the distal aorta showing the
thrombus within the vessel.
4 - Transverse image
of the distal aorta showing the aneurysm with
measurement of the
of the aorta are potentially lethal, yet are often silent
The most serious and life threatening
complication of abdominal aortic aneurysm (AAA) is
rupture of the aneurysm which results in profuse internal
bleeding. Rupture of an AAA is a serious medical
emergency and is associated with a high mortality rate.
Massive bleeding from a ruptured abdominal aortic
aneurysm into the abdominal cavity can lead to
cardiovascular collapse and shock. A ruptured abdominal
aortic aneurysm is an acute medical emergency and must be
diagnosed and treated urgently to improve the patient's
chances of survival. Approximately 15,000 people die each
year in the United States from ruptured abdominal aortic
aneurysms and some researchers estimate that the number
may be even higher.
Rupture - The single most important factor that
consistently correlates with the risk of rupture of an
AAA is its size (diameter and length). The risk of
rupture increases with increasing size of AAA and is
significantly higher when the aneurysm reaches an average
of 5.0 - 5.5 cm. and approaches 6 cm. According to the
Joint Council of the American Association for Vascular
Surgery (JCAAVS), the most accurate predictor of risk for
aneurysmal rupture is the size of the aneurysm. The
approximate risk of rupture for AAAs based on size of the
aneurysm is as follows:
0% risk below 4 cm. diameter
0.5% - 5% for 4 - 5 cm.
3% - 15% for 5 - 6 cm.
10% - 20% for 6 - 7 cm.
20% - 40% for 7 - 8 cm.
30% - 50% for diameter above 8 cm.
and some reports place this at 100% within 5
embolization – a
thrombus (blood clot) from within the aneurysm breaks off
and travels downstream. Reports vary on the incidence of
this serious complication but is probably 2-5%. Certainly,
larger aneurysms with intraluminal thrombus would appear to
pose increased risk. Duplex ultrasound plays an important
role in the diagnosis and management of aortic aneurysms
that may not be apparent clinically. Ultrasound can be used
to effectively document the presence of an AAA with a
sensitivity nearing 100%. Ultrasound is also an important
method for the surveillance of a known aneurysm for
enlargement. Some aneurysms may
remain stable and not enlarge significantly however many
will grow gradually and this proves why ultrasound
surveilance is so valuable as most physicians will recommend
surgical repair when an AAA reaches a certain
Duplex sonography plays an important role
in the diagnosis and management of aneurysms that may not be
apparent clinically. Ultrasonography can effectively be used to
document the presence of an AAA with a sensitivity nearing
100%. Ultrasonography is also an important method for the
surveillance of aneurysm enlargement. Some aneurysms may remain
stable and not even change in size, however this proves why
surveillance of an aortic aneurysm is as most patients will
seek surgical repair when the size reaches a certain diameter.
Most aortic aneurysms are followed up on every six months to
monitor the size and check for any enlargement over time. In
this case, the patient had been lost to follow-up for nearly
three years. The aneurysm had expanded dramatically from 3.7
centimeters to 5.4 centimeters and had an extensive amount of
thrombus located within the lumen. Complications of the
aneurysm in the case of this patient would be the distal
embolization which can be made by observation of the bluish
toes on physical exam. The diagnosis was confirmed by the flat
line waveforms of her toes demonstrating little or no blood
flow in the toes. We also know by the ultrasounds findings that
her extremity arteries were widely patent. Significant
obstruction would not allow the emboli to reach the toes.
Larger emboli could however block major arteries. This case
dramatically underscores the importance of regular surveillance
for abdominal aortic aneurysm!
QVI Case of the
For past cases,