February 2024 Pick of the Month

Warranted Fear

Aortic dissection is a relatively rare cause of chest pain in the emergency care setting. However, in morbidity and mortality conferences at academic emergency departments, cases of aortic dissection occupy a disproportionate amount of time and energy relative to their epidemiology. Perhaps the word “fear” is warranted for this potentially fatal condition, which can present with an initial constellation of clinical features that range from ripping midscapular pain with circulatory shock, to mild chest discomfort in a patient who is texting, lying in bed with legs crossed, and seemingly comfortable. 

The D-dimer has recently emerged as a reasonable and prudent exclusionary method, if used in conjunction with pretest probability. But many clinicians worry about the utility of existing pretest probability tools and many are generally uncertain of the evidence behind D-dimer for this indication. Also, D-dimer can take an hour to return, and every hour of delay to surgical repair increases mortality risk. Within this background, this months’ POTM by Gibbons et al., The sonographic protocol for the emergent evaluation of aortic dissections (SPEED protocol): A multicenter, prospective, observational study, provides an important advance in understanding the adjunctive role of ultrasound to diagnose and exclude proximal aortic dissection at the bedside. 

In a large, multicenter sample, the authors report impressive diagnostic sensitivity of 93.2% (95% CI 81.3–98.6), as well as excellent specificity of 90.9 (95% CI 89.2–92.5). Clearly, these diagnostic indices could help adjust the clinical pretest probability of aortic dissection at the bedside for patients with nonspecific chest pain. Moreover, most emergency clinicians will eventually face the dilemma of caring for a patient with a high suspicion of aortic dissection while the “CT scanner is down.” In this awful situation, a cardiac point-of-care ultrasound that shows some or all of the features in Table 1 from Gibbons et al. may help compel a thoracic surgeon to come in and evaluate the patient while waiting for the “CT scanner to come up again.”  Thus, the SPEED protocol is an important advance in the rapid detection of a problem that scares us all.

Jeffrey A. Kline, MD
Wayne State University School of Medicine
Editor-in-Chief