PubMed Health⌕ Search

Biomedical subjects

Aaron M Brown

Publications and source records attributed to Aaron M Brown.

7 recordsLinked to original sources
PubMed2007

Impact of a negative prior stress test on emergency physician disposition decision in ED patients with chest pain syndromes.

OBJECTIVE: Many emergency department (ED) patients with potential acute coronary syndromes (ACS) have prior visits and prior cardiac testing; however, the effect of knowledge of prior testing on the emergency physician disposition decision making is not known. We studied the impact of prior noninvasive testing (ie, stress testing) for myocardial ischemia on disposition decision making in ED patients with potential ACS. METHODS: We performed a prospective cohort study of ED patients with chest pain who received an electrocardiogram for potential ACS. Data included demographics, medical history, stress test history, and TIMI risk score. Patients were followed in-house; 30-day telephone interviews were performed for follow-up. Main outcomes were ED disposition (admit/discharge) and a composite of 30-day death, acute myocardial infarction, and revascularization stratified on the basis of prior stress testing known at the time of presentation. Standard statistical techniques were used with 95% confidence intervals (CI). RESULTS: There were 1853 patients enrolled and 97% had follow-up. Patients had a mean age of 53 +/- 14 years; 60% were women, 67% were black. There were 1491 (79%) patients without a prior stress test, 291 (16%) had a normal prior stress test result, and 89 (5%) had an abnormal prior stress test result. Admission rates were 92% (95% CI, 87%-98%) for patients with a prior abnormal stress test, 73% (95% CI, 67%-78%) for patients with a normal prior stress test, and 70% (95% CI, 67%-72%) for patients without a prior stress test. Adverse outcomes were the highest among patients with prior abnormal stress test but did not differ significantly between patients with no prior stress test and patients with prior normal stress test (10.1% [95% CI, 3.6-16.7%] vs 5.2% [95% CI, 4.1-6.4%] vs 4.8% [95% CI, 2.4-7.3%]). CONCLUSION: Patients without prior stress tests and patients with prior normal stress tests were admitted for potential ACS at the same rate and had the same 30-day cardiovascular event rates. This suggests that prior stress testing does not affect subsequent disposition decisions. Perhaps cardiac catheterization or computed tomography coronary angiograms would have more of an impact on subsequent visits, making them potentially more cost-effective in the low-risk patient.

Chest Pain↗
PubMed2006

The impact of B-type natriuretic peptide in addition to troponin I, creatine kinase-MB, and myoglobin on the risk stratification of emergency department chest pain patients with potential acute coronary syndrome.

STUDY OBJECTIVE: The emergency department (ED) evaluation of chest pain patients with potential acute coronary syndrome is limited by the initial sensitivity of cell injury markers. BNP is increased during myocardial ischemia and is associated with adverse outcomes. We determine whether the addition of B-type natriuretic peptide (BNP) to troponin I, creatine kinase-MB (CK-MB), and myoglobin increases the sensitivity and negative predictive value (NPV) for acute myocardial infarction, acute coronary syndrome, and 30-day adverse events among chest pain patients with potential acute coronary syndrome. METHODS: A convenience sample of patients aged 30 years or older and presenting to an urban academic ED with nontraumatic chest pain, thus prompting an ECG, was enrolled, and consent was obtained. Blood samples were drawn at 0 and 90 minutes. Thirty-day follow-up was performed for all enrolled patients. Main outcomes were acute myocardial infarction, acute coronary syndrome, and 30-day events (death, acute myocardial infarction, or revascularization). BNP cutoffs were derived from receiver operator characteristics curves. The sensitivity, specificity, positive predictive value (PPV), and NPV with 95% confidence intervals (CIs) were calculated with and without BNP. Differences in sensitivity and specificity with the addition of BNP were calculated with 95% CIs, and McNemar's test was performed to compare sensitivities and specificities. RESULTS: Four hundred twenty-six patients were enrolled and analyzed. The cohort was 54.7+/-13.9 years old, 47.7% men, and 63.5% black. The outcomes were acute myocardial infarction, 39 (9.2%), acute coronary syndrome, 101 (23.7%), and 30-day adverse cardiovascular events 52 (12.2%). BNP cutoffs derived were 51, 31, and 31 pg/mL for acute myocardial infarction, acute coronary syndrome, and 30-day events, respectively. The addition of BNP showed increased sensitivity at the cost of decreased specificity for all 3 outcomes, as follows: (1) acute myocardial infarction: sensitivity: 87.2% (95% CI 72.6% to 95.7%) to 97.4% (95% CI 86.5% to 100%), difference 10.3% (95% CI-0.2% to 24.6%), P=.125; specificity: 62.3% (95% CI 57.2% to 67.1%) to 47.8% (95% CI 42.7% to 52.9%), difference 14.5% (95% CI 11.1% to %18.4), P<.0001; (2) acute coronary syndrome: sensitivity: 75.2% (95% CI 65.7% to 83.3%) to 88.1% (95% CI 80.2% to 93.7%), difference 12.9% (95% CI 7.0% to 21.0%), P=.0002; specificity: 68.0% (95% CI 62.6% to 73.0%) to 48.6% (95% CI 43.1% to 54.2%), difference 19.4% (95% CI 15.2% to 24.1%), P<.0001; (3) 30-day events: sensitivity: 71.2% (95% CI 56.9% to 82.9%) to 88.5% (95% CI 76.6% to 95.7%), difference 17.3% (95% CI 7.7% to 30.3%), P=.004; specificity: 61.8% (95% CI 56.6% to 66.7%) to 43.9% (95% CI 38.8% to 49.0%), difference 17.9% (95% CI 14.2% to 22.2%), P<.0001. There were trends toward increased NPV and decreased PPV for all outcomes, and the addition of BNP achieved a NPV of 99.5% (95% CI 97.0% to 100%) compared with 98.0% (95% CI 95.3% to 99.3%) for acute myocardial infarction. CONCLUSION: The addition of BNP as a dichotomous test to troponin I, CK-MB, and myoglobin produces increased sensitivity at a cost of decreased specificity for acute myocardial infarction, acute coronary syndrome, and 30-day adverse events. Because of this tradeoff, BNP cannot be recommended for use among all ED chest pain patients. However, the improved sensitivity may make this test useful in selected cohorts when the decreased specificity is less important.

Angioplasty, Balloon, Coronary↗
PubMed2006

Prognostic value of symptoms during a normal or nonspecific electrocardiogram in emergency department patients with potential acute coronary syndrome.

OBJECTIVES: Emergency department (ED) patients with symptoms concerning for acute coronary syndrome (ACS) and a normal electrocardiogram (ECG) are at risk for adverse cardiovascular events. The authors hypothesized that patients with a normal or nonspecific ECG during symptoms have a lower risk for ACS than do those who are asymptomatic. METHODS: This was a prospective cohort study of ED patients with potential ACS. Outcomes were acute myocardial infarction (AMI), ACS, and 30-day cardiovascular events (death, AMI, revascularization). Fisher's exact test, t-tests, and logistic regression were used for data analysis. RESULTS: Of 2,593 patient visits, 2,007 patients had normal or nonspecific ECG findings. There were 1,196 who had symptoms during ECG, whereas 811 did not. Patients with symptoms at ECG acquisition were younger (49.9 vs. 55.2 years; p < 0.001) and were more likely to be black (70% vs. 64%; p = 0.002), female (63% vs. 58%; p = 0.03), and to have used cocaine (5% vs. 2%; p = 0.004). They were less likely to have hypertension (49% vs. 58%; p < 0.001), and diabetes (22% vs. 17%; p = 0.002). Patients with and without symptoms were equally likely to have AMI (both 2.8%; p > 0.99), ACS (10.1% vs. 11.5%; p = 0.34), and 30-day adverse outcomes (both 5.3%; p > 0.99). After adjustment for baseline cardiovascular-risk factors, odds ratios for patients with symptoms at the time of ECG acquisition were not significantly different for any of the outcomes: AMI (1.1; 95% confidence interval [CI] = 0.6 to 1.9); ACS (1.1; 95% CI = 0.8 to 1.4); or 30-day events (1.2; 95% CI = 0.8 to 1.9). CONCLUSIONS: Patients who are symptomatic during acquisition of a normal or nonspecific ECG have rates of adverse cardiovascular events similar to those of patients without symptoms. Clinicians should not rely on the absence of ECG abnormalities during symptoms to help exclude ACS.

Cohort Studies↗
PubMed2004

Heteroligated metallomacrocycles generated via the weak-link approach.

Sequential reaction of two different hemilabile ligands (Ph(2)PCH(2)CH(2)X)(2)Ar (X = S, Ar = C(6)H(4) or C(6)(CH(3))(4); X = NCH(3), Ar = C(6)H(4); X = O, Ar = 9,10-C(14)H(8)) with a Rh(I) metal center resulted in the formation of heteroligated metallomacrocycles in high yield. The specific reaction conditions for each pair of hemilabile ligands are discussed. The solid-state structure of [[1,4-(Ph(2)PCH(2)CH(2)S)(2)C(6)H(4)]-[1,4-(Ph(2)PCH(2)CH(2)S)(2)C(6)(CH(3))(4)]Rh(2)](BF(4))(2), as determined by X-ray crystallography, is presented.

Journal Article↗
PubMed2004

Halide-induced supramolecular ligand rearrangement.

A novel reaction involving the halide-induced rearrangement of ligands within supramolecular Rh(I) complexes containing hemilabile ligands is presented. Three analogous bis- and trishemilabile ligands have been synthesized to construct bi- and trimetallic Rh(I) macrocyclic complexes. An intentionally added halide source results in the formal rotation of only one hemilabile ligand along the axis that is perpendicular to the plane defined by the aryl backbone of the hemilabile ligands. X-ray structures, as determined by X-ray crystallography, of key intermediates and products are presented.

Journal Article↗