“When can you discontinue anticoagulation when someone has converted from atrial fibrillation to sinus rhythm?”

Let’s say you admit a 75 year old man with pneumonia and sepsis. His EKG shows atrial fibrillation, which as far as anyone knows, is new. He is treated with antibiotics, fluids, and started on a heparin drip for the atrial fibrillation.

Two days later, his telemetry shows normal sinus rhythm. The patient feels much better than when he came in. Past medical history is significant for hypertension and hyperlipidemia. A TTE shows no valvular disease. The patient asks you, “Doc, do I have to keep taking a blood thinner? Do I have to take it for the rest of my life?”

In this case, the conversion to NSR was spontaneous. My brief search did not turn up studies looking at anticoagulation dosing/duration in patients who spontaneously convert to NSR, so I’m extrapolating from recommendations for patients who undergo planned cardioversion.

In cases of planned cardioversion, short-term vs. long-term anticoagulation afterwards is based on the CHADS VASC score and patient-specific risk factors for stroke/thromboembolism. This is regardless of how long atrial fibrillation has been present for (the all-important “48 hours” is arbitrary and most helpful for categorizing afib for study purposes).
CHADS VASC=0 : most cardiologists would anticoagulate for 4 weeks
CHADS VASC ≥ 1: most cardiologists would anticoagulate for at least 4 weeks…and might continue long-term anticoagulation if the CHADS VASC is considered “high risk,” and definitely if there is history like valve disease or replacement, or past stroke.

Our patient in the case above is relatively healthy but has a CHADS VASC score of 3. It would be reasonable to keep him anticoagulated and discharge with your favorite anticoagulant. He and his primary care doctor should discuss risks/benefits of anticoagulation, and if the patient agrees, it would be preferable for him to continue anticoagulation long-term.

Remember: when making decisions about anticoagulation, it’s not the kind of atrial fibrillation that matters (it doesn’t matter if it’s unprovoked, provoked, or new onset)–it’s the patient’s underlying risk factors.

When should you consider cardioversion for atrial fibrillation?

Emergent

  • afib with rapid rate that causes hemodynamic instability or severe heart failure, MI

Inpatient

  • symptomatic, persistent afib (causing CHF exacerbations, for example)
  • symptomatic, new afib due to an underlying cause (e.g., hyperthyroidism, post-op, PE) after that cause is treated
  • before cardioverting, ask about anticoagulation–if afib has been present for >48 hrs, either TEE to rule out atrial thrombus or 3-4 weeks of anticoagulation is recommended. That being said, even when cardioversion is done in the ER with no anticoagulation the risk of clot at 30 days is 0% – 0.7%

Outpatient

  • patients with infrequent, but symptomatic episodes who don’t have a pattern of spontaneously converting back to sinus rhythm
  • as part of a plan for long-term rhythm control, cardioversion is performed before starting patients on oral antiarrhythmics

Cardiology is more likely to say no to patients who are…

  • stable, completely asymptomatic patients 🙂
  • >80 years age, multiple medical comorbidities
  • patients who have not been anticoagulated or are not candidates for anticoagulation
  • left atrial dilation or other structural features that make afib more likely to recur

When to stop or restart antiplatelets and anticoagulation during GI bleed?

Let’s say one of your patients is an 80 year old male with a history of CAD, HTN, HLD, and CKD stage III presenting with nausea and abdominal pain. He also complains of a “choking” sensation for the past week. You notice that his hemoglobin is around 9 g/dL; a couple of months ago it was 13 g/dL. Given his symptoms, you consult GI and he undergoes EGD that shows LA grade C esophagitis and some gastritis that gets biopsied. He is started on a PPI BID, and as you are going through his discharge med list, you wonder if his aspirin, which was held on admission, is safe to be restarted–and if so, when?

Luckily, to this particular scenario, the answer is pretty clear. He doesn’t have a high bleeding risk otherwise, and in patients with CAD, as shown in two meta-analyses cited by this Hospitalist piece, it’s safer to restart aspirin immediately rather than hold it indefinitely. (Aspirin probably didn’t need to be held in the first place.)

Other scenarios are not so clear. What if this wasn’t just a baby aspirin, but warfarin or another agent like dabigatran or apixaban? What if the patient had an NSTEMI and got a stent 3 months ago? What if the bleeding were so severe he was getting daily blood transfusions? In the graphic below, I have tried to show that stopping and resuming antiplatelets and anticoagulation is about weighing benefits of stopping anticoagulation vs. risks of thrombosis for each individual patient–there is no blanket statement that can be made.

Generally speaking, for resuming antiplatelets and anticoagulation, you should do it as soon as hemostasis has been achieved, or when endoscopy shows no active bleeding. The ACC recommends restarting warfarin within 24 hours after hemostasis (on a bridge if needed). There’s no data to support restarting a DOAC within a certain amount of time, but, extrapolating, it’s probably fine to restart within a day.

For information about specific medications and specific endoscopic procedures, the ASGE has an excellent practice guideline published in 2016. Just to entice you, here’s an example of one of the tables:

What is catheter-directed therapy? (EKOS)

Catheter-directed lysis therapy delivers thrombolytics (like tPA) via a catheter. Consider it for extensive DVT or submassive or massive PE when you have concerns about bleeding risks.

EKOS (EndoWave Catheter Infusion System) is a device that is supposed to enhance catheter-directed therapy with the use of ultrasonic waves. Ooh! There are several parts of the EKOS experience to be aware of:

  • Control unit–the pump. Can adjust settings and infusion rates. Beeps at you when there are problems.
  • Catheter/drug delivery device–infuses the thrombolytic at a set rate
  • Ultrasound core–supposedly increases thrombolytic efficacy, decreases fibrin clotting
  • Coolant (usually normal saline or heparin-infused normal saline)–to prevent the ultrasound core from overheating/causing tissue damage

A video is worth a thousand pictures: check out the EKOS inservice video on YouTube.

This review goes into some of the nitty-gritty of managing EKOS. The thrombolytic of your choice is usually set to an infusion rate of 1-5 mg/hour. The catheter usually stays in for 18-24 hours. Consider stopping thrombolysis once a maximum dose has been given (like 18-24 mg), 18-24 hours has passed, or repeat ECHO or CTA shows improvement. Once the clinical goal is achieved, the catheters may be removed without repeat imaging. Trend fibrinogen levels: most conservative protocols would reduce or stop the infusion when fibrinogen <200 mg/dL.

While there are studies proving the efficacy and relative safety of EKOS (such as SEATTLE II), there are no high-quality studies that compare EKOS with other kinds of catheter-directed therapy, or against the oldie goodie systemic tPA. Therefore, EKOS seems promising, but people are reluctant to recommend it over other kinds of therapy.

Tangent: not all contraindications to tPA are created equal; see this review on the absolute and relative contraindications to thrombolytics. In addition, even when there are contraindications to tPA, you might still be able to use it and get lucky, as in this interesting case report.

IV vs. PO steroids for asthma

Treating an asthma exacerbation with steroids–and the sooner the better–is undisputed. And it makes intuitive sense that higher doses of steroids work better, and that IV steroids work better than PO steroids, right?

Well, the answer’s not so simple.

First of all, I see patients >18 years of age (usually). A lot of the literature on asthma was studied in the pediatric population, so while the results might be generalizable, we don’t know for sure.

Is there a maximum dose for steroids?

No, although this Cochrane review suggests that upwards of 100 mg prednisone daily, you’re probably not getting much benefit. This separate Cochrane review concludes most of the evidence is pretty low-quality, so it’s hard to make a strong recommendation. Side effects such as hyperglycemia and agitation/delirium are dose dependent.

Are IV steroids better than PO steroids?

I’ve heard some people suggest that if someone has “failed” PO steroids, then they should get a trial of IV steroids for at least 48 hours. On the one hand, this seems reasonable, because you want to avoid intubating the patient for worsening respiratory distress. On the other hand, there’s no evidence to support the assertion that IV steroids are better. See this pediatric study or this randomized adult study. This review makes the argument that it can be hard to ascertain the true effect of IV steroids in retrospective studies because (1) there is often no true “control” or “placebo” group (2) more severe asthma attacks are more likely to get IV steroids upfront, so you have a “confounding by severity” problem.

IV steroids make sense as a one-time dose for initial therapy in the ED, or for patients who are too obtunded or can’t take PO for some other reason. Then again, I’ve had a couple of cases where we used IV steroids 4-5 days into someone’s asthma treatment, and they got better. There’s the literature, and then there’s practice.

Checking residuals (gastric residuals, that is)

Ah, the fun tradition of “residual 250 cc…hold TF?” This national survey shows that there is very wide variance in how residuals are checked, and how much is “concerning.” 200 cc? 250 cc? 500 cc? Going once, going twice…

Disclaimer: the information below is about adults. Who knows if the answers are the same for a pediatric population? Not me.

This ACG clinical guideline on nutrition in the hospital setting opened my eyes (mostly to how much we don’t know about managing nutrition). The authors write that checking residuals “has been shown to be a poor marker of true gastric volume, gastric emptying, risk of aspiration, pneumonia, and poor outcomes.” The sensitivity of residuals for predicting aspiration is 2-8%. This JAMA study shows that in the ICU, checking residuals didn’t affect development of ventilation-associated pneumonia. In other papers, one of the authors has advocated for the abolishment of checking residuals in nursing practice (see this link for good, practical information).

When is checking residuals useful?

Checking residuals is thought to be most useful in the first 48 hours of initiating tube feeds, as patients are getting increased to goal rate. If the residuals are building up (see below), it might be an indication to pause the tube feeds and make sure there’s nothing wrong with the tube, there are no tube feeds leaking into the peritoneum (this is actually something terrifying that can happen), etc. If your patient is intubated/sedated/obtunded, residuals are the only measure you have–but if the patient is awake and alert, you could talk to them and ask if they’re having worsening nausea, bloating, etc.

How high is too high? When do tube feeds need to be held for residuals?

I don’t know where the adage, “hold TF for residuals >200 cc” comes from. Abbott Nutrition states that when residuals > 500 cc, consider holding tube feeds. (For perspective, the human stomach can accomodate +/- 1 liter.) Check your institutional hospital policy, but…the general message of this post is that you shouldn’t be too worried.

Does checking residuals have harmful effects?

It is known that protein clots when the pH <5.0 (stomach acid pH is usually between 1.5-3.5). Could checking residuals lead to refluxing clotted protein, increasing the likelihood of clogging the tube? This small study (n=30) says, yes. In the group undergoing regular residual checks, there were 10 clogging events, compared to 1 in the no-residual checks group.

Checking residuals can also lead to tube feeds being held unnecessarily–if higher residuals aren’t a good sign of impending aspiration, we’re just holding tube feeds for hours at a time, depriving patients of the nutrition they’re supposed to be getting.