While COVID-19 occupied much of our bandwidth in 2020, new medical literature on other important topics still descended upon us faster than it could be consumed. We’ve already covered some of this in previous ACEP Now updates touching on critical care, tranexamic acid, and spontaneous pneumothorax. But those barely scratched the surface of the year in research.
Here’s a quick tour of more of the most talked-about articles from the past year.
Cardiology
High-sensitivity troponin assays have continued to become more commonly used, and the HIGH-US study is one of the most thorough large-scale validations of the rapid rule-out algorithms demonstrated in Europe.1 This study evaluated two pathways for diagnosis of acute myocardial infarction (AMI), generating consistently mixed results. The most important result from this study is the continued demonstration that a single high-sensitivity troponin below the limit of detection can be sufficient for ruling out AMI. Also, using these new assays for rapid repeat testing is safe, with good sensitivity for AMI. Unfortunately, these assays and algorithms still fail to fully provide clarity, as nearly a third of the patients evaluated still required “continued evaluations” despite the additional precision offered in these tests.
Much has been written about using computed tomography coronary angiography (CTCA) to exclude acute coronary syndrome (ACS) in the initial evaluation of chest pain in the emergency department. Interestingly, there may yet be a role for CTCA even following the diagnosis of ACS. In a study in which CTCA was performed prior to invasive coronary angiography in patients with a non-ST segment elevation ACS, nearly a quarter of patients were shown to have coronary stenosis under 50 percent.2 The implication for downstream management is that resource-intensive and costly procedures might be avoided in a large cohort of patients.
Speaking of avoiding low-value procedures, another study took a population-level look at noninvasive cardiac testing.3 This study, performed in the Kaiser Permanente Southern California population, tried to tease out an association between receipt of (primarily) early stress testing on subsequent myocardial infarction and mortality. Based on these data, the authors concluded there may be a benefit to such testing, but between 200 and 500 tests would need to be performed to inform management to improve the outcome of one additional patient. These data may provide some of the first insights into beneficial effects of follow-up noninvasive testing but clearly demonstrate the need for further studies to elucidate the highest-yield population.
Finally, the last point of curiosity involved physician interpretations of the electrocardiogram (ECG). Many physicians poke fun at the erroneous interpretations of the computer embedded in the ECG machine, but a study collating the accuracy of physician ECG reading was humbling.4 In a meta-analysis of ECG interpretation skills, after discarding medical students and trainees, pooled performance for physician accuracy sat squarely between 60 and 80 percent. Much depends on the specifics of each included study, but it should be clear there is always work to be done on improving ECG reading skills—and the computers may be better than we thought.
Intra-Abdominal Infections
One of the highest-profile articles published this year concerned the use of antibiotics for appendicitis.5 Several earlier studies indicated a nonsurgical approach is safe, and a majority of patients have a durable long-term avoidance of appendectomy. However, the proportion of patients who do ultimately require an appendectomy remains nontrivial, leaving many still finding value in an initial surgical strategy. The most important insight from this most recent trial is the role an appendicolith identified on initial imaging plays in treatment failure. Of those who failed an initial nonsurgical approach, 41 percent had an appendicolith compared to only 25 percent of those without. These data further detail the information potentially incorporated into shared decision-making conversations.
As antibiotic treatment increases for appendicitis, a decrease in antibiotic use is being seen for diverticulitis. In yet another trial, patients with diverticulitis managed with and without antibiotics showed similar outcomes.6 This time, the patient population involved those admitted to the hospital with uncomplicated diverticulitis, using a primary outcome of in-hospital length of stay. Although there was no difference in this outcome, and no statistical difference in secondary adverse outcomes, it remains likely that a few patients benefit from antibiotics; figuring out which ones is not so easy though. As with appendicitis, additional data are necessary for teasing out any features of those patients for whom antibiotics play a role.
Advanced Imaging
Yet again, we find there is no clear mechanism to stave off so-called contrast-induced nephropathy (CIN) from CT imaging. The Kompas trial enrolled patients with stage 3 chronic kidney disease undergoing contrast-enhanced CT and found no benefit to the use of sodium bicarbonate infusion as prehydration.7 The authors conducting the trial concluded that withholding prehydration is safe and cost-effective. These data add yet another piece to the contrast imaging puzzle. The more data showing the futility of any intervention for reducing CIN we gather, the more difficult it becomes to paint a picture of imaging-associated CIN as a true disease entity—at least in the setting of emergency department imaging, where contrast doses are substantially smaller than in other situations, such as interventional radiologic procedures.
This is effectively the new stance adopted by a joint statement by the American College of Radiology and the National Kidney Foundation.8 In their statement, narrowly focused on patients receiving intravenous contrast for advanced imaging, they described a distinction between contrast-associated acute kidney injury and contrast-induced acute kidney injury. Contrast-associated acute kidney injury is common, but it’s seen as being related to the underlying medical illness rather than caused by the contrast administration itself. Their summary described inconsistent evidence supporting the existence of contrast-induced acute kidney injury, noting modern low-osmolar contrast media are less likely to be nephrotoxic than prior-generation products. Only those with the most severe renal impairment are seen as potentially reasonable candidates for gentle volume expansion prior to contrast administration prior to advanced imaging.
Cerebrovascular Disease
Systems of stroke care continue to reorganize in response to access to endovascular intervention (clot retrieval/thrombectomy) and the ever-changing time windows for treatment. Persistent questions remain regarding the necessity of alteplase prior to early endovascular intervention. The DIRECT-MT trial provided some of the most robust evidence to date, suggesting only the smallest advantages in reperfusion from alteplase administration.9 Reperfusion, however, remains a surrogate for measurably improved clinical outcomes, and once taking adverse events into account, the overall picture appears to favor endovascular intervention alone. It should be considered reasonable to skip alteplase prior to endovascular intervention, but these data may be rendered moot as Tenecteplase (which is given more quickly and thus creates fewer delays) gradually replaces alteplase.
Screening patients for subarachnoid hemorrhage remains a challenge, despite multiple validations of the Ottawa Subarachnoid Hemorrhage Rule. Developed as a zero-miss screening tool, the specificity of this decision instrument creates challenges in implementation. In a recent study, practice patterns were evaluated before and after implementing routine use of the Ottawa rule and a six-hour CT rule.10 Overall, few differences were observed, likely owing to prestudy familiarity with both changes (ie, many clinicians had already altered their practices prior to any “official” implementation practices). However, a handful of interesting missed cases were noted, including one in a profoundly anemic patient, rendering the Ottawa rule less than zero-miss in some rare circumstances. When using noncontrast CT to exclude subarachnoid hemorrhage, consider contributors to false-negative scans.
See you next year!
The opinions expressed herein are solely those of Dr. Radecki and do not necessarily reflect those of his employer or academic affiliates.
References
- Nowak RM, Christenson RH, Jacobsen G, et al. Performance of novel high-sensitivity cardiac troponin I assays for 0/1-hour and 0/2- to 3-hour evaluations for acute myocardial infarction: results from the HIGH-US study. Ann Emerg Med. 2020;76(1):1-13.
- Linde JJ, Kelbæk H, Hansen TF, et al. Coronary CT angiography in patients with non-ST-segment elevation acute coronary syndrome. J Am Coll Cardiol. 2020;75(5):453-463.
- Kawatkar AA, Sharp AL, Baecker AS, et al. Early noninvasive cardiac testing after emergency department evaluation for suspected acute coronary syndrome. JAMA Intern Med. 2020:e204325.
- Cook DA, Oh S-Y, Pusic MV. Accuracy of physicians’ electrocardiogram interpretations: a systematic review and meta-analysis. JAMA Intern Med. 2020;180(11):1-11.
- CODA Collaborative, Flum DR, Davidson GH, et al. A randomized trial comparing antibiotics with appendectomy for appendicitis. N Engl J Med. 2020;383(20):1907-1919.
- Jaung R, Nisbet S, Gosselink MP, et al. Antibiotics do not reduce length of hospital stay for uncomplicated diverticulitis in a pragmatic double-blind randomized trial. Clin Gastroenterol Hepatol. 2020:S1542-3565(20)30426-2.
- Timal RJ, Kooiman J, Sijpkens YWJ, et al. Effect of no prehydration vs sodium bicarbonate prehydration prior to contrast-enhanced computed tomography in the prevention of postcontrast acute kidney injury in adults with chronic kidney disease: the Kompas randomized clinical trial. JAMA Intern Med. 2020;180:533-541.
- Davenport MS, Perazella MA, Yee J, et al. Use of intravenous iodinated contrast media in patients with kidney disease: consensus statements from the American College of Radiology and the National Kidney Foundation. Kidney Med. 2020;2(1):85-93.
- Yang P, Zhang Y, Zhang L, et al. Endovascular thrombectomy with or without intravenous alteplase in acute stroke. N Engl J Med. 2020;382(21):1981-1993.
- Perry JJ, Sivilotti MLA, Émond M, et al. Prospective implementation of the Ottawa Subarachnoid Hemorrhage Rule and 6-hour computed tomography rule. Stroke. 2020;51(2):424-430.
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