Tag Archives: anticoagulation

Pharmacy, Prevention

Anticoagulants And The Elderly: Are They Being Appropriately Treated?

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About 2.3 million people, or a bit less than 1% of the US population, have atrial fibrillation. This condition is commonly managed with anticoagulants to reduce the risk of stroke. Unfortunately, the elderly represent a large subset of those with a-fib. And the older we get, the more likely we are to fall. About half of those over 80 will fall once a year.

Are all of these elderly patients being treated with anticoagulants appropriately? Several scoring systems have been developed that allow us to predict the likelihood of ischemic stroke. Looking at it another way, they allow us to judge the appropriateness of using an anticoagulant to prevent such an event.

The original CHADS2 score was developed using retrospective Medicare data in the US. The newer CHA2DS2-VASC score used prospective data from multiple countries. However, the accuracy is about the same as the original CHADS2 score. But because the newer system has three more variables, it adds a few more people to the high-risk group who should receive an anticoagulant.

The higher the CHA2DS2-VASC score, the more likely one is to have an ischemic stroke. The threshold to justify anticoagulation seems to vary a bit, with some saying >1 and others going with >2. Here’s a chart that shows how the stroke risk increases.


Stroke risk per year with CHA2DS2-VASC score

Whereas CHA2DS2-VASC predicts the risk of clotting (ischemic stroke), the HAS-BLED score looks at the risk of bleeding. It includes clinical conditions, labile INR, and concomitant use of NSAIDs, aspirin or alcohol, but not a history of falls.

Proper management of atrial fibrillation in the elderly must carefully balance both of these risks to reduce potential harm as much as possible. A HAS-BLED score of >3 indicates a need to clinically review the risk-benefit ratio of anticoagulation. It does not provide an absolute threshold to stop it.

A group at Henry Ford Hospital in Detroit, a Level I trauma center, retrospectively reviewed their experience with patients who fell while taking an anticoagulant for atrial fibrillation. They calculated CHA2DS2-VASC and HAS-BLED for each and evaluated the appropriateness of their anticoagulation regimen.

Here are the factoids:

  • A total of 242 patients were reviewed, and the average age was 78
  • The average CHA2DS2-VASC score was 5, and the average HAS-BLED was 3
  • Only 1.6% were considered to be receiving an anticoagulant inappropriately (CHA2DS2-VASC 0 or 1)
  • Nearly 9% of patients were dead 30 days after the fall

Bottom line: The authors found that their population was appropriately anticoagulated. But they also noted that the morbidity and mortality risk was high, and was independent of age and comorbidities.

There are tools available to help us judge whether an elderly patient should be taking an anticoagulant for atrial fibrillation. The tool for predicting bleeding risk, however, is not as good for trauma patients. It ignores the added risk from falling, which is very common in the elderly.

Every patient admitted to the trauma service after a fall should have a critical assessment of their need for anticoagulation. The specific drug they are taking (reversible vs irreversible) should also be examined. If there is any question regarding appropriateness, the primary care provider should be contacted personally to discuss and modify their drug regimen. Don’t just rely on them reading the hospital discharge summary. Falls can be and are frequently fatal, just not immediately. Inappropriate use of anticoagulants can certainly contribute to this problem, so do your part to reduce that risk.

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Reference: Falls, anticoagulation, and the elderly: are we inappropriately treating atrial fibrillation in this high-risk population? JACS 225(4S1):S53-S54, 2017.

General

EAST 2016: Lower Mortality In Patients Taking Newer Oral Anticoagulants vs Warfarin

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How not to write your abstract! The full title is this:

Trauma Patients on New Oral Anticoagulation Agents Have Lower Mortality Than Warfarin

Now let’s look at what it really says. This was a retrospective trauma registry review from a single Level I trauma center. Over a 14 month period, 275 of 1994 admitted patients were on anticoagulants.

Here are the (misleading) factoids and my comments:

  • Patients on warfarin had a higher mortality (13%) than those on new oral agents (NOA) (6%). (I can’t duplicate the statistical significance calculation)
  • Patients taking any anticoagulant were admitted to an ICU more often (44-50% vs 36%). (Duh! This just shows their usual practice, nothing new)
  • Patients on warfarin were more statistically likely to receive prothrombin complex concentrate. (Double duh! Because it doesn’t work for NOAs?)
  • The authors pointed out a trend toward more NOA use in this graph. (Really? It goes from 11 to 14 with wide monthly variations!)
image

Bottom line: This is why it’s so important to read the entire abstract and think about the stats. And ultimately, it’s even more important to read the whole paper! They don’t always say what you think they say!

Reference: Trauma patients on new oral anti-coagulation agents have lower mortality than those on warfarin. EAST 2016 Oral abstract #24.

General

Delayed Intracranial Hemorrhage In Patients On Anticoagulants

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A sizable portion of our population is taking one type of anticoagulant or another. Heck, even golf star Arnold Palmer and comedian Kevin Nealon are on Xarelto! Any trauma professional, and anyone who reads the package insert, knows that there is an increased risk of bleeding if they are injured while taking these drugs, whether it be warfarin or the new, novel anticoagulants.

But does the risk stop soon after injury? That is the presumption at many hospitals that initially treat these patients. They are seen in the ED, examined, scanned, and sent home if nothing is found. Is this a safe practice?

I have personally seen a patient who had an initially clean CT present within 12 hours after ED discharge with a catastrophic bleed and die. Yes, this is anecdotal, but I have talked to other trauma professionals with similar experiences. If this were just a minor complication, no big deal. But they died. Big problem for everyone involved.

So what does the literature say? Unfortunately, it consists of a collection of relatively small studies. Here are the collected factoids that I can glean from them:

  • Most are retrospective, observational studies 
  • Most are from a single hospital, which may miss readmissions to other facilities in the area
  • The delayed bleeding rate is about 0.5% to 1%
  • Some papers recommended discharging patients with a normal head CT and giving them instructions to return if new symptoms develop (this is what happened with my patient; what if they live alone or in a care center where these may not be recognized?!)
  • A few papers did identify patients needing neurosurgical intervention or who died
  • Immediate bleeds were more common with antiplatelet agents, delayed bleeds were more common with warfarin
  • I could find nothing that looked at this problem in patients taking novel anticoagulants like Pradaxa or Xarelto

Bottom line: The literature provides little guidance at this point. A good multi-institutional trial is needed to generate the numbers to tell us what to do. While we get around to this, I recommend that a selective brief observation (12 hrs) protocol be adopted. This protocol recognizes that subclinical bleeding may be present on initial presentation, and that a little more time is needed for it to declare itself.

Here is a link to our protocol. If the initial head CT is negative and the INR is less than 2.5, we will only discharge the patient if all of these criteria are true:

  • Age < 65
  • No skull fx
  • No new focal neurologic deficits
  • No soft tissue injury visible on CT (hematoma, laceration)
  • GCS = 15
  • No persistent vomiting
  • Brief TBI screen passed (Short Blessed Test, link here)

Most do not pass all of these, usually failing the age criterion. They are admitted for observation and neurologic monitoring for 12 hours, at which time the head CT is repeated. If it is still normal, then they can go home.

And although this protocol was designed with warfarin in mind, we apply it to patients taking novel anticoagulants like Pradaxa and Xarelto as well. We’ve had no epic fails yet, but I keep my fingers crossed!

Related posts:

References:

  • Management of minor head injury in patients receiving oral anticoagulant therapy: a prospective study of a 24-hour observation protocol. Ann Emerg Med 59(6):451-455, 2012.
  • Immediate and delayed traumatic intracranial hemorrhage in patients with head trauma and preinjury warfarin or clopidogrel use. Ann Emerg Med 59(6):460-468, 2012.
  • Delayed intracranial hemorrhage after blunt trauma: are patients on preinjury anticoagulants and prescription antiplatelet agents at risk? J Trauma 71(6):1600-1604, 2011.
  • Low risk of late intracranial complications in mild traumatic brain injury patients using oral anticoagulation after an initial normal brain computed tomography scan: education instead of hospitalization. Eur J Neurol 21(7):1021-1025, 2014.
  • Can anticoagulated patients be discharged home safely from the emergency department after minor head injury? J Emerg Med 46(3):410-417, 2014.
  • Patients with blunt head trauma on anticoagulation and antiplatelet medications: can they be safely discharged after a normal initial cranial computed tomography scan? Am Surg 80(6):610-613, 2014.
General

What The Heck? The Answer!

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Yesterday I posted an image of an unusual chest CT. The patient had been involved in a motorcycle crash weeks ago, and presented with new onset chest pain and weakness.

Exam of the chest showed a hint of diffuse swelling on the left side and moderate tenderness. Chest x-ray suggested a mild effusion on the left. I showed one slide of the CT yesterday, which showed a large amount of complex material in the chest wall. This is most likely a mixture of blood and clot. 

Here is another slice of the CT that is more revealing:

Now you can see that there are multiple rib fractures present. While comparing the original and the recent scan, it is apparent that the fractures are more displaced on the recent one. Upon closer questioning the patient admits that he did fall down the day before the new pain and swelling occurred.

And by the way, he forgot to mention the fact that he had developed deep venous thrombosis and was taking warfarin! And also by the way, his blood pressures were becoming a bit soft.

I would consider this life-threatening bleeding! Crystalloid and blood resuscitate immediately. Reverse the anticoaguation quickly, using prothrombin complex concentrate (PCC, preferably 4-factor). Then send him to interventional radiology to see if there are any active bleeders that can be embolized. Finally, it’s off to the ICU to finish up the resuscitation and restore him to normal!

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General

The Downside Of NOT Taking Your Anticoagulant

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We’ve all been faced with injured patients who are taking some kind of anticoagulant, and it complicates their care. Many trauma professionals just say, “they just shouldn’t take this stuff any more." Why can’t we just stop them in patients at risk for injury (e.g. an elderly patient who falls frequently)?

Two major risk groups come to mind: those taking the meds who have DVT (or a propensity to get it), and patients with atrial fibrillation who take them to decrease stroke risk. I was not able to find much info (yet) on the former category. But there is a series of nicely done studies based on work from the Framingham Heart Study.

The Framingham study started in 1948, and has been following over 5,000 people for the development of cardiovascular disease. In this particular analysis, 5070 patients who were initially free of disease were analyzed for development of atrial fib and occurrence of stroke. Anticoagulants were seldom used in this group.

The authors found that the prevalence of stroke increased with age in patients with atrial fib. The percentage that could be attributed to a-fib also increased. The following summarizes their numbers:

  • Age 50-59: 0.5 strokes per 100 patients, attributable risk 1.5%
  • Age 60-69: 1.8 strokes per 100 patients, attributable risk 2.8%
  • Age 70-79: 4.8 strokes per 100 patients, attributable risk 9.9%
  • Age 80-89: 8.8 strokes per 100 patients, attributable risk 23.5%

Bottom line: The risk of having a stroke just because a patient has atrial fibrillation goes up significantly with age. So setting an age cutoff for taking an anticoagulant doesn’t make sense. Unfortunately, increasing age also means increasing risk of injury from falls. Warfarin definitely cuts that risk, and it happens to be relatively easily reversbile. However, the newer non-reversible drugs change the equation, shifting the risk/benefit ratio too far toward the dark side. We need some good analyses to see if it really makes sense to move everybody to these new (expensive) drugs just to make it easier to dose and monitor. The existing studies on them only look at stroke, but don’t take injury morbidity and mortality into account.

Reference: Atrial fibrillation as an independent risk factor for stroke: the Framingham study. Stroke 22:983-988, 1991.

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