Inferior Vena Cava (IVC) Filters and Haptoglobin Level

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Inferior Vena Cava (IVC) Filters and Haptoglobin
Level Matthew Elkins M.D. Ph.D., Laura Cooling
M.D., M.S., Donald Giacherio Ph.D. University of
Michigan Health System, Ann Arbor, Michigan
Introduction
Results
Results
Baseline Haptoglobin Levels Pre-IVC haptoglobin
levels ranged widely between individuals (Fig.
2), including 2 individuals with haptoglobins of
2 and 4 mg mg/dL each. These 2 individuals were
excluded from further analysis.
Low serum haptoglobin levels are often utilized
as a marker for acute intravascular immune
hemolysis (Levy et al. 2009). However, any state
resulting in hemolysis will result in decreased
serum haptoglobin. Our index patient was a 52
year old man with a positive DAT (IgG, eluate
negative) and conflicting laboratory findings of
hemolysis. Although the patient had a stable
hemoglobin, normal LDH and bilirubin, he had an
extremely low haptoglobin (lt10 mg/dL). His past
medical history was significant for several DVTs
requiring placement of an inferior vena cava
(IVC) filter (Fig. 1). We posited that the low
serum haptoglobin level in this patient may be
due to chronic low-level shear hemolysis at the
level of the IVC filter. A literature search
showed no prior investigations into the effect of
IVC filter placement on serum haptoglobin levels.
Figure 4. Comparison of the absolute serum
haptoglobin at baseline, 7, and 14 days following
IVC placement. Shown are Group I (mean SD) and
all 3 patients in Group 2. The percent baseline
haptoglobin also shown. NS, not significant
Figure 2. Distribution of serum haptoglobin
levels in patients immediately prior (Day 0) to
placement of an IVC filter.
Chart Review for Causes of Low Haptoglobin Nine
patients from Group 1 (4-9) and Group 2 (1-3)
were examined for potential causes of low
haptoglobin including liver dysfunction,
bleeding, transfusions, infection, surgery, and
thrombolysis (Table 1). There was no
correlation between specific clinical factors and
low haptoglobin between the two groups.
Figure 1. IVC filter placed into the patients on
this study. The Gunther Tulip IVC Filter (a
model of the Greenfield venous filter). Image
from Cook Medical.
Haptoglobin Levels After IVC placement In the
majority of patients (Group 1, Fig. 3),
haptoglobin levels rose immediately following IVC
placement, consistent with an acute phase
response. There was a significant rise in the
first 24 hours (p0.026), which continued to
slowly rise over the first 7 days (6/6 patients).
By the end of 2 weeks, haptoglobin levels tended
to decrease toward baseline levels although
haptoglobin levels remained elevated (Fig. 4).
Hct transfusions bleeding infection surgery thrombolysis Bilirubin AST LDH
1 33.2 none no no no no ND ND ND
2 26.7 Day 1 3u RBCs Day 2 1u RBC no yes, infected incision no yes, Day 0 0.6 38 ND
3 28.8 none no yes MSSA line sepsis no no ND ND ND
4 35 Day 6 3u RBCs Ongoing widening of aneurysm no Day 6 IR stent placed no 0.2 17 ND
5 29.3 Day 0 2u RBCs Day 1 2u RBCs Day 1 melena yes UTI and sepsis no no ND ND ND
6 29.8 Day 1 2u RBCs Post-surgical DVT no Day -1 spinal fusion no 0.5 71 ND
7 24.7 Day 2 2u RBCs no Osteomyelitis Day 2 spinal decompression no 0.2 11 ND
8 29 Day 13 2u RBCs no yes Cdiff no no 15.8 225 464
9 34.3 Day 0 4u RBCs no yes PNA no no 0.6 49 ND
Figure 3. Relative percent change in serum
haptoglobin following IVC filter placement in 20
patients. Group 1 17/20 patients with no
significant decrease in haptoglobin (mean SE).
Group 2 3 patients with a gt 50 decrease in
haptoglobin at 7 days.
Methods
Twenty-two patients were investigated for a
change in serum haptoglobin levels following
placement of an IVC filter. Serum haptoglobin
levels were obtained immediately prior to IVC
placement and then daily over a period of 3-14
days. Serum haptoglobin was measured by an
immunoturbidimetric assay on a Roche COBAS
Integra 800 automated chemistry analyzer (Roche
Diagnostics Corporation, Indianapolis, IN). In
this assay, haptoglobin forms immune complexes
with specific anti-human haptoglobin antisera,
and the increase in turbidity is detected at 340
nm. Both the absolute and relative () change in
haptoglobin from pre-IVC baseline were determined
for each patient. Patients with gt50 decrease in
haptoglobin were examined separately.
Significance was determined by student t-test
(2-tailed, paired). Both graphics and statistics
were performed with commercial software
(Kaliedograph, Synergy Software).
Table 1 Possible confounding causes of
haptoglobin decrease in 9 patients followed for
1-2 weeks after IVC filter placement. Group 2
(Pts 1-3) shown in yellow. Labs values from day
6 or 7.
Conclusions
This study suggests that up to 20 (3/20)
patients can experience a significant drop in
haptoglobin following IVC filter placement. The
presence of an IVC filter should be considered
when evaluating causes of a low serum haptoglobin
In contrast to Group 1, 3 patients demonstrated a
gt 50 decrease in haptoglobin over the first 7
days following IVC placement (Group 2, Fig 3).
In Group 2, the relative decrease in haptoglobin
ranged from 57- 80 (p 0.02, Fig 4). A 14 day
sample was available in 1 patient (Pt 1). As
shown, the haptoglobin continued to fall,
decreasing 98 of baseline levels. By the end of
2 weeks, the absolute haptoglobin in this patient
was abnormal (5 mg/dL, Fig. 4) suggestive of
intravascular hemolysis.
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