Author’s Disclosure Statement: The authors report no actual or potential conflict of interest in relation to this article.
Dr. Worley is Instructor, Department of Emergency Medicine, NewYork-Presbyterian Hospital/Columbia University, New York, NY. Dr. Mattson is Resident, Department of Emergency Medicine, NewYork-Presbyterian Hospital, New York, NY. Dr. Bhatt is Assistant Professor, Department of Emergency Medicine, NewYork-Presbyterian Hospital/Columbia University, New York, NY.
In an external validation study, the AIR and Alvarado scores were calculated on a series of 941 patients (aged 1 to 97 years) being evaluated for possible appendicitis; 201 patients were younger than 18.13 At a cutoff of greater than 4, the sensitivity and specificity were found to be 93% and 85% for the AIR and 90% and 55% for Alvarado.13 In a cohort of 182 patients (aged 4 to 75 years), a score of 4 or greater on the AIR and Alvarado was found to have comparable sensitivity to that of a senior surgical consultant for detecting appendicitis—with sensitivities of 94%, 93%, and 90% respectively.14 Subsequently, the original investigators undertook a large multicenter implementation study of the AIR at 24 hospitals of patients (aged 5 to 96 years) with suspected appendicitis. As compared to the pre-implementation group, using AIR to categorize patients as low risk resulted in significantly fewer imaging studies, admissions, and surgical explorations.15
Comment: The AIR has the benefit of recent prospective studies that assess performance of the rule in settings that mirror the practice environments of most EPs today. The classification of rebound tenderness as light, medium, or strong may be difficult to ascertain. Ultimately, reductions in imaging, admissions, and surgical explorations are important goals and EPs might benefit from using this rule to guide imaging.
CHEST
HEART Score
The increasingly popular HEART score, first developed by physicians in the Netherlands in 2008, seeks to risk-stratify patients presenting to the ED with suspected cardiac chest pain without ST-elevation myocardial infarction (STEMI). It scores patients 0 to 2 on 5 different characteristics (with a total scored of 10 possible points):
History: 2 points for highly suspicious, 1 point for moderately suspicious EKG: 2 points for significant ST deviation, 1 point for nonspecific repolarization disturbance Age: 2 points for age 65 years or greater, 1 point for age 45-64 years Risk Factors: 2 points for 3 or more risk factors or history of atherosclerotic disease, 1 point for 1 to 2 risk factors Troponin: 2 points for troponin value >3 times the normal limit, 1 point for value 1-3 times the normal limit.
The authors developed these 5 categories “based on clinical experience and current medical literature,” and then applied the rule to 122 chest pain patients in the ED, finding a higher incidence of major adverse coronary events (MACE) with increasing score: 2.5% for low risk score of 0-3, 20.3% for intermediate risk score of 4-6, and 72.7% for score 7 or higher.16 The score has been retrospectively and prospectively validated.17,18 In a study of 2440 patients, the low risk group had a MACE of 1.7%, and the score had a c-statistic of 0.83, outperforming Thrombolysis in Myocardial Infarction (TIMI) and GRACE c-statistics of 0.75 and 0.70, respectively.18 In 2013, investigators calculated the HEART score on a multinational database of 2906 chest pain patients, finding a negative predictive value of 98.3% for MACE with HEART score less than or equal to 3.19
In the United States, Mahler et al have produced a series of 3 articles validating the HEART score and demonstrating its use in reducing cardiac testing and length of stay. In 1070 patients admitted to their observation unit, who were deemed low risk by physician assessment and TIMI <2, a score of less than or equal to 3 had a negative predictive value of 99.4% for MACE; the inclusion of serial troponins resulted in sensitivity of 100%, specificity of 83.1%, and negative predictive value of 100%.20 The team then conducted a secondary analysis of chest pain patients enrolled in a large multicenter trial (MIDAS) and compared HEART score, the North American Chest Pain Rule, and unstructured clinical assessment.21 Both rules had high sensitivities, but the HEART score identified 20% of patients suitable for early discharge, as compared to 4% for the North American Chest Pain Rule.21 Finally, Mahler’s team performed a randomized control trial of 282 patients investigating whether the HEART score with serial troponins compared with usual care could safely reduce cardiac testing.22 The HEART pathway resulted in an absolute reduction of 12.1% in cardiac testing, and median reduction in length of stay by 12 hours, with no missed MACE in discharged patients.22