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Patient Safety Tip
of the Week
December
14, 2021
Delayed
Hemorrhage After Head Trauma in Anticoagulated Patients
Here’s a controversy that just won’t go away
– what is the risk of missing an intracranial hemorrhage after a negative CT
scan in patients with head trauma who are on anticoagulants or antithrombotics?
We’ve all seen isolated cases of such delayed
hemorrhage. But large series have demonstrated the incidence of delayed
hemorrhage to be quite low, suggesting that repeat imaging is not cost-effective
and probably not indicated in most cases (see our September 21, 2021 Patient
Safety Tip of the Week “Repeat
CT in Anticoagulated Patients After Minor Head Trauma Not Cost-Effective”).
Researchers at Allegheny
Health Network in Pennsylvania recently did a retrospective analysis of over 1,000
patients with head trauma over a three-year period (Chang
2021). Patients were included in the study if they were on antiplatelet
and anticoagulant medications, including DOAC’s (direct anticoagulants), and
suffered head trauma. The radiology reports for the initial examinations on
these patients included a recommendation for repeat imaging to evaluate for delayed
hemorrhage. Approximately 50% of patients in which repeat imaging was
recommended received repeat imaging. Repeat examinations were typically
performed within 24 hours (average follow-up time was 21 hours and 99% were
within 3 days). There was a 1.8% incidence of delayed hemorrhage and 0.4%
overall mortality. Patients on warfarin and clopidogrel had a higher rate of delayed
hemorrhage (3.2%), compared to 0.9% in the DOAC group, and the difference was
statistically significant (p<0.01). All deaths were in the
clopidogrel/warfarin group. Patients on DOAC’s had a significantly lower risk
of both delayed hemorrhage and mortality than those on warfarin/clopidogrel.
Moreover, taking
any blood thinner concurrently with aspirin significantly increased the risk of
delayed hemorrhage. In an interview with Medscape (Frellick
2021),
Chang noted that about a third of the
patients were taking aspirin in addition to anticoagulants and that, of the
bleeds, nearly two thirds were in patients with concurrent aspirin therapy. Chang
recommended repeat imaging should be obtained with every patient with anticoagulant
or antiplatelet medicines who is also taking aspirin,
You’ll recall that, in our September
21, 2021 Patient Safety Tip of the Week “Repeat
CT in Anticoagulated Patients After Minor Head Trauma Not Cost-Effective”, we highlighted a study by Borst et al. (Borst 2021) in patients on anticoagulants who had head
trauma. The initial head computed tomography was negative in 82% of 1,377
patients. Of those with an initial negative head computed tomography, 12
patients (0.9%) developed an intracranial hemorrhage that was identified on the
second head computed tomography (6 had intraventricular hemorrhage, 3 had
subdural hematoma, 2 had subarachnoid hemorrhage, and 1 had an intraparenchymal
hemorrhage). None of the patients with delayed intracranial hemorrhage
developed a change in neurologic status, required an intracranial pressure
monitor, or underwent neurosurgical intervention.
And see our July 8, 2014 Patient Safety Tip
of the Week “Update:
Minor Head Trauma in the Anticoagulated Patient”
that highlighted several other studies on the issue. In that column we noted
the paucity of data on patients taking DOAC’s, in whom the degree of
anticoagulation is not easily measurable. So, the current Chang study is
reassuring in that it seems to show less risk for delayed hemorrhage in
patients taking DOAC’s.
Contrast the following two positions taken
after the 2 most recent studies on this issue:
- Based on the findings of the Borst study
(Borst 2021), the institutional protocol at the
study institution was updated. Repeat head CT scans are no longer
performed unless the patient has an INR>3.5 or a mental status decline
on neuro checks performed every 2 hours during their 12- to 24-hour
admission for observation.
- Based on the finding in his study, Chang
and his colleagues “recommend follow-up CT for patients who had no initial
intracranial hemorrhage from head trauma who are taking one of the older
blood thinners and for patients who take any blood thinner along with
aspirin. Unless there are external signs of trauma, follow-up CT is
unnecessary for patients who take one of the newer blood thinners and do
not take aspirin” (Susman 2021).
Overall, it seems the frequency of delayed
intracranial hemorrhage in patients on anticoagulants is relatively low, and
the frequency of such hemorrhage requiring intervention is even lower. We seem
to be defining a population at greater risk of such delayed hemorrhage: older
patients, those on older anticoagulants (particularly those with INR’s beyond
the usual therapeutic range), and those on concomitant antiplatelet therapy.
One key parameter that is missing in
virtually all the studies on this issue is timing of the initial CT scan in relation to the head trauma. Our own suspicion is that there is probably
a “sweet spot” for timing of the initial CT scan in such
patients. It might turn out that scans done at, for example, 8-12 hours
following the head trauma might pick up all the hemorrhages. If that proves to
be the case, then a single CT scan done at that time may be all that is necessary.
So future research should attempt to answer that question. Alternatively, maybe
the authors of previous studies can re-analyze their data and include this
important parameter.
And, of course, it is important to remind all
patients (and their families or caregivers) of symptoms to watch for
(drowsiness, nausea/vomiting, or focal neurological symptoms) following head
trauma regardless of whether they are on anticoagulants or not.
Also, keep in mind that the many clinical
decision rules for imaging following mild head trauma (see list below) are not intended for patients who are on anticoagulants.
We
are always trying to balance patient safety vs. the costs incurred by unnecessary
testing or treatment. The Borst study (and several others in our prior columns)
have estimated the costs incurred from overuse of CT scanning in this
population, though we challenged the methodology used by Borst et al. in our September 21, 2021 Patient Safety
Tip of the Week “Repeat
CT in Anticoagulated Patients After Minor Head Trauma Not Cost-Effective” and suggest that cost is actually much
less. Getting the answer to the question we posed above may help us
appropriately balance safety and cost.
Some of our previous columns on head trauma
in the anticoagulated patient:
April
16, 2007 “Falls With Injury”
July
17, 2007 “Falls in Patients on Coumadin or Heparin or
Other Anticoagulants”
June 5, 2012 “Minor
Head Trauma in the Anticoagulated Patient”.
July 8, 2014
“Update:
Minor Head Trauma in the Anticoagulated Patient”
August 21, 2018 “Delayed CT Scan in the Anticoagulated Patient”
September
21, 2021 “Repeat
CT in Anticoagulated Patients After Minor Head Trauma Not Cost-Effective”
Some of our previous columns on CT scans in
minor head trauma:
April
16, 2007 “Falls With Injury”
July
17, 2007 “Falls in Patients on Coumadin or Heparin or
Other Anticoagulants”
March 2010 “CATCH:
New Clinical Decision Rule for CT in Pediatric Head Trauma”
November 23, 2010 “Focus
on Cumulative Radiation Exposure”
June 5, 2012 “Minor
Head Trauma in the Anticoagulated Patient”.
July 8, 2014
“Update:
Minor Head Trauma in the Anticoagulated Patient”
January 2017 “Still Too Many CT Scans for Pediatric
Appendicitis”
March 2017
“Update on CT Scanning after Minor Head Trauma”
September 2017 “Clinical Decision Rule Success”
August 21, 2018 “Delayed CT Scan in the Anticoagulated Patient”
September
21, 2021 “Repeat
CT in Anticoagulated Patients After Minor Head Trauma Not Cost-Effective”
References:
Chang
W, et al. Delayed Posttraumatic Intracranial Hemorrhage in Patients on
Anticoagulant/antiplatelet Medications: Three Year Experience. 2021 Virtual
Meeting of the Radiological Society of North America (RSNA); November 2021
Frellick M. Older Anticoagulants Increase Risk of Delayed
Brain Hemorrhage After Trauma. Medscape Medical News 2021;
December 02, 2021
https://www.medscape.com/viewarticle/964069
Borst
J, Godat LN, Berndtson AE,
et al. Repeat head computed tomography for anticoagulated patients with an
initial negative scan is not cost-effective. Surgery 2021; 170(2): 623-627
Published online: March 26, 2021
https://www.surgjournal.com/article/S0039-6060(21)00117-3/fulltext
Susman
E. Head Trauma Patients on Blood Thinners Need Surveillance
—
Delayed intracranial bleeding observed in patients. MedPage
Today 2021; December 1,
2021
https://www.medpagetoday.com/meetingcoverage/rsna/95962
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