Feb 2, 2018

Burden of proof

The story

The more daydreaming you do on rounds, the more vague answers you give when people ask you about the plan. Does the same hold true for A-fib burden and heart failure symptoms?

The background

Vanc and Zosyn, trach and PEG, Dilaudid and Benadryl. Count atrial fibrillation (A-fib) and congestive heart failure (CHF) among the hospital’s great pairings. Half of patients with new CHF have A-fib, and a third of patients with new A-fib have CHF. Regardless of which comes first, cardiologists agree that weak hearts perform worse when they beat irregularly. Restoring sinus rhythm in CHF should provide patients with clinical benefit, but for the most part antiarrhythmic drugs haven't worked.

The trial

CASTLE-AF compared catheter ablation to medical therapy in 360 patients with A-fib, CHF symptoms, and an ejection fraction (EF) < 35%. After a median follow up of just over 3 years, patients assigned to ablation were 40% less likely to meet a combined endpoint of death from any cause or hospitalization, including a clear mortality benefit at 3 years post-ablation. Ablation patients saw an increase in EF and were able to walk longer distances. Benefits are thought to be due to a reduction in A-fib burden: ablation didn't cure A-fib, but instead cut the time patients spent in A-fib by two-thirds compared to medical therapy.

The takeaway

CASTLE-AF offers compelling evidence that reducing A-fib burden with ablation improves CHF outcomes. Experts view the results as paradigm changing, so expect more ablations in your EP lab soon. 

Say it on rounds

When you've cut your Netflix binge watching to about one season at a time

You have a ways to go, and so do your patients who are cutting down on cigarettes. A meta-analysis of over 140 prospective cohort studies found that just one cigarette per day elevated the risk of coronary artery disease and stroke. Using regression modeling, the researchers estimated that one smoke per day accounted for 40 - 50% of the excess risk of a whole pack, while 5 cigs per day elevated this risk to 55 - 65%. Relative risks from low cigarette consumption were higher in women than men.

When ICU rounds extend well past lunch

Talk about munchies. Obstructive sleep apnea (OSA) patients can relate: an RCT of 75 OSA patients found that dronabinol (Marinol, a synthetic THC) produced dose-dependent reductions in the Apnea-Hypopnea Index compared to placebo. Patients in the treatment group reported improved daytime sleepiness and higher treatment satisfaction. While the mechanism of action is not completely clear, dronabinol is thought to decrease afferent vagal activity, which in turn leads to decreased apnea.

When you think to yourself 'what a quiet night'

That jinx is on you. Patients who suffered in-hospital cardiac arrest (IHCA) were more likely to survive during working hours then on nights or weekends, says a registry study of 150,000 US patients from 2000 to 2014. While survival rates increased over time (25% in 2014 vs. 16% in 2000), the gap between weekdays and off hours persisted. Asystole arrests were more common at night, meaning you and your night crew may be working with more difficult cases. 

Brush up

Primary biliary cirrhosis

Suspect primary biliary cirrhosis (PBC) in middle-aged women with abnormal liver labs. The disease may smolder for years before signs of liver dysfunction are present. Bloodwork demonstrating cholestatic liver labs and a positive anti-mitochrondrial antibody is sufficient for diagnosis, but you'll want to order an abdominal ultrasound to rule out biliary obstruction and assess the degree of fibrosis. Watch for debilitating fatigue and pruritus that often do not correlate with disease severity.

What's the evidence

For ursodeoxycholic acid (UDCA) in PBC? A 2006 study of 200 PBC patients found that UDCA improved transplant-free survival compared to predicted values. UDCA works best when started early, and remains the only FDA-approved drug for PBC. About 40% of patients do not respond to UDCA and may need alternative treatments or eventual liver transplant.

What your business friends are talking about

Mega-names Amazon, JPMorgan, and Warren Buffett's Berkshire Hathaway are teaming up to improve healthcare outcomes and reduce costs. The big announcement sent shockwaves through the insurance industry, but details remain sparse.

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