Pulmonary embolism after insertion of a Greenfield filter [review; review, tutorial] [see comments]

              558 • JAOA • Vol 102 • No 10 • October 2002 Promisloff • Case report
CASE REPORT
This report describes a case in which a patient had a Green-field
filter placed at the time of diagnosis of deep vein
thrombosis (DVT) when he was asymptomatic for pul-monary
embolism. Later in the patient’s hospital course, a
typical clinical picture of pulmonary embolism developed.
The issues examined in this report include: (1) the
incidence of asymptomatic pulmonary embolism; (2) the
value of the baseline ventilation perfusion (VQ) lung scan
for the diagnosis of DVT; and (3) the value of an echocar-diogram
in diagnosing pulmonary embolism.
It appears reasonable that patients in whom DVT is
diagnosed undergo baseline VQ scanning. This proce-dure
would prevent the misdiagnosis of a new pulmonary
embolism while the patient is on anticoagulation therapy
and possibly avoid unnecessary invasive diagnostic pro-cedures.
The case described demonstrates the usefulness
of the echocardiogram and a transthoracic echo in the diag-nosis
of pulmonary embolism. It also points out the sur-prisingly
high incidence of silent pulmonary embolism in
patients in whom DVT is diagnosed.
(Key words: deep vein thrombosis, echocardiogram,
Greenfield filter, pulmonary embolism, ventilation per-fusion
lung scan)
The diagnosis of pulmonary embolism is frequently diffi-cult
and challenging. We are increasingly faced with an
aging population with complex diseases that predispose to
pulmonary embolism. Pulmonary embolism is a direct result
of deep vein thrombosis (DVT), and a diagnosis of DVT is of
prime importance in accurately diagnosing pulmonary
embolism.
As the embolism moves through the right side of the
heart, the echocardiogram becomes a potentially valuable tool
to diagnose pulmonary embolism, either directly (by visual-izing
clot) or indirectly (by assessing right ventricular pressure
and volume and pulmonary artery pressure).
The following case illustrates the relationship between
DVT and pulmonary embolism and the potential role of the
echocardiogram. It illustrates the value of looking for pul-monary
embolism in the patient with DVT without pulmonary
symptoms and the surprisingly high incidence of asymp-tomatic
pulmonary embolism in the setting of DVT.
Report of case
A 74-year-old man with a past medical history significant for
glioblastoma, coronary artery disease, type II diabetes mel-litus,
and atrial fibrillation complained of swelling of the left
leg that had been present for approximately 1 month. The
swelling had worsened during the past week. He denied
having fever, skin lesions, recent trauma, surgery, or history of
thrombotic events. He had no complaints related to the right
leg. Findings of the review of systems was otherwise negative
for symptoms of pulmonary embolism, including cough, dysp-nea,
hemoptysis, and chest pain.
His past medical history, in addition to that previously
cited, included subtotal resection of a glioblastoma followed by
cranial irradiation. His radiation therapy was continuing at
the time of this presentation. He also had a history of benign
prostatic hypertrophy and had undergone transurethral resec-tion
of the prostate.
His medications at the time he was seen for the current
complaint were dexamethasone, diltiazem hydrochloride,
phenytoin, ranitidine hydrochloride, and chlorpropamide.
His family history was unremarkable, including that for throm-botic
disorders.
He had a past history of smoking cigars, but he denied
tobacco use for at least the past 7 years. He had a past history
of heavy alcohol use, but none in the past 12 years.
At physical examination, the patient was elderly
appearing and in no acute distress. He was alert and oriented.
His temperature was 98.7 F, pulse rate was 92 beats per minute
and regular. His blood pressure was 132/90 mm Hg. Respi-rations
were 16/min. Candidiasis of the oral mucosa was
noted. Findings of the neck, lungs, and heart examination
were normal. The left calf was tender with 1 pretibial pitting
edema. The right leg and both arms were not edematous.
Findings of vascular and neurologic examinations were normal.
Laboratory data included normal values for serum
sodium, potassium, serum chloride, venous plasma bicar-bonate,
blood urea nitrogen, and serum creatinine. The blood
glucose level was 240 mg/dL. The white blood cell count was
11,300/mm3, with 77% band neutrophils, 13% lymphocytes, 8%
monocytes, and 1% basophils. The hemoglobin level was 12.9
g/dL, with a hematocrit of 40.6 mL/dL. Platelet count was
131,000/mm3. Prothrombin time was 13 seconds with a con-trol
of 11.8 seconds. Partial thromboplastin time was 26.2 sec-onds
with a control of 29.7 seconds.
The patient’s chest x-ray film showed no abnormality,
Pulmonary embolism after insertion of a Greenfield filter
ROBERT A. PROMISLOFF, DO
Address correspondence to: Robert A. Promisloff, DO, Respiratory Associ-ates,
Ltd, 1001 City Line Ave, West Bldg 113, Wynnewood, PA 19096-3902.
JAOA • Vol 102 • No 10 • October 2002 • 559
CASE REPORT
Promisloff • Case report
and the electrocardiogram (ECG) demonstrated normal sinus
rhythm and was otherwise normal, except for left atrial enlarge-ment.
Doppler ultrasound examination of the lower extremities
was done, demonstrating thrombosis of the left superficial and
popliteal veins, with patent veins in the right leg. A diagnosis
of DVT of the left leg was made.
Because of the history of intracranial tumor, the patient
was considered not to be a candidate for anticoagulation
therapy, and a Greenfield filter was placed via the right femoral
vein. Its position at the level of L2-3 was confirmed radio-graphically.
The patient remained stable until 5 days after insertion of
the filter, at which time he complained of pain in the right side
of the groin. Doppler ultrasound examination of the legs at
that time demonstrated not only left superficial femoral and
popliteal venous thrombosis, but also right common femoral,
superficial femoral, and popliteal thrombosis. The patient still
had no pulmonary complaints.
The next day, 6 days after insertion of the Greenfield
filter, the patient complained of dyspnea of acute onset. He
was tachypneic and tachycardic. Arterial blood gas determi-nations
at that time revealed the following: pH, 7.30; PCO2, 29
mm Hg; and PO2, 82 mm Hg on 3 L of oxygen. The ECG
showed atrial fibrillation. A chest x-ray film at that time was
notable for oligemia without any changes from prior studies.
Ventilation perfusion (VQ) lung scanning was done, demon-strating
multiple, bilateral VQ mismatches, greater on the right
side. No baseline VQ lung scan was available for comparison.
A transthoracic echocardiogram showed normal left ventricular
size and function along with left ventricular hypertrophy. It also
showed right atrial and right ventricular enlargements with
normal right ventricular function. Linear echoes that were con-sistent
with venous thrombosis in transit were seen in the infe-rior
vena cava .
Transesophageal echocardiograhy was also done, which
demonstrated, in addition to the foregoing findings, linear soft
tissue casts in the inferior vena cava and main pulmonary
artery without cardiac masses. This finding was also thought
to be consistent with thrombosis in transit. The patient was
then started on systemic anticoagulation therapy.
The remainder of the patient’s hospital course was without
incident except for occasional self-limited episodes of atrial fi-brillation.
He was maintained on appropriate heparin therapy,
and warfarin sodium therapy was begun. He was discharged
on warfarin therapy, with an international normalized ratio
(INR) of 2.3.
Discussion
This case raises several interesting issues, including:
  The incidence of asymptomatic pulmonary embolus at the
time of presentation of deep venous thrombosis (DVT);
  the value of a baseline VQ lung scan at the time of diag-nosis
of DVT; and
  the value of echocardiograms, including a transesophage-al
echocardiogram as an adjuvant in the diagnosis of pul-monary
embolism.
In the patient described, the most likely etiology for pul-monary
embolism diagnosed after placement of the Greenfield
filter is asymptomatic pulmonary embolism before filter place-ment
or embolism to the right side of the heart before filter
placement with subsequent pulmonary embolism. The other
possible source would be a clot propagation proximally from
the Greenfield filter, an entity described previously,1,2 The
rarity of such an event is well documented. Studies by Kistner
et al4 and Lemone,5 Plate et al,6 and Huisman et al7 document
the surprisingly high incidence of silent pulmonary embolism
in patients in whom DVT is diagnosed, varying from 22% to
55% of patients in these studies.
Monreal et al8 assembled a larger group of patients and
studied this same issue, yielding an incidence of pulmonary
embolism of roughly 30% in patients with DVT asymptomatic
for pulmonary embolism. Monreal et al also noted that signs
or symptoms of pulmonary embolism developed in 5% of
their study population after the initiation of anticoagulation
therapy without a change on the VQ lung scan from baseline.
This 5% represents a population that might have been con-sidered
a failure of anticoagulation therapy in the absence of
a baseline VQ lung scan.
It appears reasonable that baseline VQ lung scanning be
done in patients with diagnosed DVT. This procedure would
prevent the misdiagnosis of new pulmonary embolism while
patients are on anticoagulation therapy. The avoidance of
such misdiagnosis would prevent unnecessary invasive diag-nostic
procedures and unnecessary changes in therapy.
The case described here also illustrates the usefulness of
the echocardiogram in the diagnosis of pulmonary embolism.
Cases documenting the use of transthoracic echocardiograhy
to identify intracardiac thromboembolism associated with
pulmonary embolism include those by Starkey and de Bono9
and Kumar and Gallagher.10
Starkey and de Bono9 describe a woman with a coiled
thromboembolism lodged in a probe-patent foramen ovale, first
noted by transthoracic echocardiogram and confirmed on
autopsy, associated with fatal pulmonary embolism.
Kumar et al10 report three cases. The first was of a man
with a mobile right atrial mass seen by echocardiography,
presumably embolus, associated with fatal pulmonary
embolism. The second case describes a man with a tubular
mass extending from the right atrium to the right ventricular
outflow tract, associated with symptomatic, nonfatal pul-monary
embolism. The third case involved a young woman
with surgically confirmed right atrial thrombus, associated
with signs and symptoms of pulmonary embolism. In general,
echocardiographic signs of pulmonary embolism include high
ventricular pressure, pulmonary hypertension, and tricuspid
insufficiency as well as actual visualization of the thrombus in
the right atrium, right ventricle, or pulmonary artery.
560 • JAOA • Vol 102 • No 10 • October 2002
CASE REPORT
Our report describes transthoracic echocardiographic
findings of an inferior vena cava thrombus in transit associated
with pulmonary embolism. Additionally, transesophageal
echocardiography confirmed the transthoracic findings and
additionally noted thrombus in transit in the main pulmonary
artery without intracardiac mass. The use of transesophageal
echocardiography to aid in diagnosis of pulmonary embolism
has not been well described, but the modality appears to be
highly sensitive.
The role of echocardiography, either transthoracic or
transesophageal, in diagnosis of pulmonary embolism is lim-ited
by the transitory nature of thromboembolism as it passes
through the inferior vena cava and right side of the heart to the
pulmonary circulation. However, in those cases in which the
echocardiogram identifies an intracardiac or intravascular
mass suggestive of thromboembolism or echocardiographic
findings of right ventricle overload or pulmonary hypertension
occur in the absence of prior disease of the right side of the
heart, the diagnosis of pulmonary embolism is extremely likely
and can be made in association with other signs and symptoms
typical of pulmonary embolism. Normal findings on an
echocardiogram should not be used to rule out a pulmonary
embolism.
Comment
We have presented a report of a case in which a patient with
diagnosed DVT had a Greenfield filter placed at a time when
he was asymptomatic for pulmonary embolism. Later in his
hospital course, a typical clinical picture of pulmonary
embolism developed, and the diagnosis was made in part
with the identification of inferior vena cava and pulmonary
artery thromboembolism demonstrated by transthoracic and
transesophageal echocardiography. Additionally, the previ-ously
documented high incidence of silent pulmonary
embolism with DVT suggests benefit in routinely obtaining VQ
lung scans in those patients in whom acute DVT is diagnosed.
References
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Promisloff • Case report