Friday, January 4, 2013

Angiography After Cardiac Arrest

This is the worst sort of paper – nuggets of truth mired in systematic flaws.  There's certainly no ill intent by the authors to mislead, it's simply the nature of this sort of retrospective review.

The PROCAT consortium has been publishing studies of their post-arrest protocols for several years.  They're huge proponents of early coronary angiography following resuscitation for out-of-hospital arrest – and this is another in a string of articles demonstrating that patients going to coronary angiography after out-of-hospital arrest have improved outcomes.  Of the 1274 patients in their cohort, 745 received early coronary angiography, 447 identified a culprit lesion, and 347 underwent PCI.  The survival rate was 46% in patients undergoing PCI.

However, this number is conflated by other confounding variables known to be associated with good outcomes following cardiac arrest – coronary lesions are likely to be associated with VT/VF, which were also associated with good outcomes.  Additionally, significantly more survivors received therapeutic hypothermia than non-survivors, illustrating the massive problem with viewing this sort of report with anything other than reasoned curiosity: rampant selection bias.  Patients survived because they were selected for interventions based on individualized prognostic features, treatments were not applied evenly across the population.

There is absolutely a subset of OHCA that benefits from early coronary angiography – but this benefit should not be generalized to the inappropriate allocation of resources associated with taking all OHCA to the cath lab after resuscitation.

"Benefit of an early and systematic imaging procedure after cardiac arrest: Insights
from the PROCAT (Parisian Region Out of Hospital Cardiac Arrest) registry"

Wednesday, January 2, 2013

The Latest Prognostication for Stroke

We have a fairly robust vascular neurology program at my institution, and – unsurprisingly – they're rather pro-thrombolysis.  While our disagreements over the efficacy of thrombolysis for acute strokes are generally set aside in a truce stemming from academic and research interests, the main philosophical difference between our services remains this: the difference between eligible and indicated.

Vascular neurology tends to treat these terms as synonymous regarding thrombolysis and acute stroke, while it's clear from the literature that not every patient benefits from thrombolysis.  The most recent issue of Neurology features another prognostic tool, the SPAN-100, which is the simplest by far: NIHSS + age.  If this score is >100, fewer patients will benefit from tPA than will be harmed.  There's a quality-of-life discussion to be had regarding individualized treatment decisions in SPAN-positive patients, and this is derived from a very small cohort, but it's consistent with the remaining literature.

The accompanying editorial is also pro-thrombolysis, but does recognize these scoring systems are important clinical tools in educating patients and families regarding the potential for benefits and harms. Most importantly, this table from the editorial summarizes the growing body of literature available to assist the decision-making process:

I look forward to seeing these develop such that clinicians have better tools with which to separate eligible from indicated.

"Stroke Prognostication using Age and NIH Stroke Scale: SPAN-100"

Monday, December 31, 2012

Evidence Summary for Bell's Palsy

Although the incidence of stroke in young people is rising, some of these "strokes" can still be clinically diagnosed with Bell's Palsy.

However, once the diagnosis is made, the practice variation is extensive.  In light of this, the American Academy of Neurology has published an update to their evidence-based guidelines for the treatment of Bell's Palsy.

Short answer:
 - Steroids are good, with a 12 to 15% increased chance of functional recovery.
 - Antivirals have no consistent evidence of benefit.

Long answer:
 - Only ~4% of Bell's Palsy sufferers are left with severe residual deficits, with the remainder fully recovering or with slight/mild deficits.  Some folks would pose the question whether any of these treatments are necessary, considering the minimal absolute benefits, even if relative benefits are consistent.

Another risk/benefit decision to discuss with patients.

"Evidence-based guideline update: Steroids and antivirals for Bell palsy : Report of the Guideline Development Subcommittee of the American Academy of Neurology"