Diffenderfer LE, Shah P, Bahl A. Abdominal aortic aneurysm screening for high-risk cardiac patients in the emergency department. J Emerg Med Trauma Acute Care. 2015;2015(1):2. doi:10.5339/jemtac.2015.2
Clinical Question: What is the prevalence of AAA among “high-risk” cardiac patients that are admitted to rule out acute coronary syndrome (ACS)
Bottom Line: Prevalence of AAA in a single level one trauma center in high-risk cardiac patients admitted for ACS rule out was 8.9%. The authors suggested this increased prevalence in comparison to the general adult population warrants screening of this specific population in the emergency department.
Major Points/Background: AAA was defined as >3cm and measured at three sites along the aorta. The adult general population prevalence of AAA is 1 - 1.5%. The USPTF (2019) recommends: 1 time screening for AAA in men 65-75 if they have a history of smoking - Grade B (moderate evidence net benefit is moderate to substantial) In men 65-75 consider individualized cases and other risk factors (medical history, FH, risk factors, personal values). Known risk factors for AAA include, caucasian race, increased age, male gender, smoking history, possibly HTN/HLD as well as association reported by Madaric between CAD and AAA, Nakayama suggests existence of CAD may warrant AAA screening.
Design: Pilot, Single center prospective surveillance study. N = 90 patients (originally n = 109, 19 patients excluded due to inadequate imaging).
Setting: Level One Trauma, Tertiary Care Facility with 118,000 patient annual census in CA, USA Enrollment: 109 patients recruited over a period of 10 months, actual recruitment dates not specified. Population: Inclusion: Patients were eligible if they were Caucasian, male, over 50 years of age, with a history of smoking, and admitted to the Telemetry unit for chest pain, shortness of breath, syncope, or other qualifying complaints justifying evaluation for ACS. Exclusion: Patient lacked the capacity to consent, or a known history of AAA
Primary Outcome: Presence of AAA in patients presenting with complaints warranting admission for ACS rule out. 8.9% of patients presenting with ED complaints warranting ACS rule out were found to have AAA, a rate 4-8 times greater than national prevalence in adults
Takeaway: If these findings hold with a study evaluating a larger sample size, this segment of the patient population may warrant AAA screening. It may be more feasible for AAA screening in this admitted population to occur following admission rather than adding unnecessary or screening workup in the emergency department. Perhaps this could be done as an additional study while the patient undergoes cardiac echocardiography during their hospitalization or even as an outpatient following the identification of the patient as “high-risk” for AAA. It is notable that 3/8 of the patients discovered to have AAA would not have met the USPTF criteria for screening as they were younger than 65.
Criticism: This was a single center study with a small sample size (n = 90) included in the analysis. There was variability in the experience of those conducting imaging, 25 total individuals including, R1, R2, R3, and clinical faculty were involved in obtaining images, each had been trained in US imaging of the aorta as well as received a 1-hour refresher course. There was a loss of 18 patients due to inadequate imaging. In this reader’s mind it is likely that these patients did not have AAA or imaging would have been followed up, this would have lowered prevalence of AAA in the sample to 7.3% from the recorded 8.9%. This would have made the prevalence of patients with AAA in this study closer to that of AAA in high-risk patients found in previous studies as cited by the authors (5.15 - 6.7 %). Age was nearly significantly different in AAA vs non-AAA groups (p 0.07), this is a possible confounder given the very small sample sizes.
Future Directions: It would have been interesting to see if screening changed the number of patients seen per hour by the providers or the RVU’s generated by the practitioners. I would be interested in seeing this screening implemented in the inpatient setting following admission for ACS rule out, or perhaps in an outpatient setting as an add-on to the initial primary care visit following discharge.
Post by Aaron Kulig, MS4