Immediate exercise testing to evaluate low-risk patients presenting to the emergency department with chest pain

OBJECTIVES: The aim of this study was to determine whether nicotine, a constituent of cigarette smoke, contributes to acute endothelial dysfunction after smoking one cigarette. BACKGROUND: Animal studies suggest that nicotine might cause an impairment of endothelium-dependent vasodilation via an increase in oxidative stress. METHODS: Sixteen healthy smokers were entered into a randomized, observer-blinded crossover study comparing the effects of nicotine nasal spray (1-mg nicotine) and cigarette smoke (1-mg nicotine, 12 mg tar) on vascular reactivity in the brachial artery. Using high-resolution ultrasound, flow-mediated dilation (FMD) and endothelium-independent, nitroglycerin-induced dilation were assessed at baseline and 20 min after the administration of nicotine (spray or cigarette). RESULTS: In response to similar increases in nicotine serum levels, FMD values declined from 10.2 +/- 4.4% to 6.7 +/- 4.0% after the spray (mean difference: -3.6 +/- 2.0%, 95% confidence interval: -4.6; -2.5, p < 0.0001) and from 9.4 +/- 3.8% to 4.3 +/- 2.8% after the cigarette (-5.1 +/- 2.6%, -6.5; -3.7, p < 0.0001). Nitroglycerin-induced dilation remained similar within both periods. Performing a period effect analysis of variance, a significant influence on FMD was found for the mode of administration (p = 0.017) and the baseline value (p = 0.021). The effect on FMD was more pronounced after the cigarette than after the spray (estimated average effect difference: 1.9% FMD). Oxidation parameters did not increase significantly after nicotine spray or tobacco exposure. CONCLUSIONS: These results demonstrate that nicotine alone causes acute endothelial dysfunction, although to a lesser extent than smoking a cigarette of the same nicotine yield. However, the precise mechanisms by which nicotine leads to this altered vascular reactivity remain unclear.     

Identification of patients at risk by graded exercise testing in an emergency department chest pain center

The study applied a retrospective follow-up design to determine the prognostic effect of graded exercise testing (GXT) in patients with low- to moderate-risk chest pain evaluated in an emergency department 9-hour protocol chest pain center (CPC) from January 1, 1993 to August 1, 1996. The cohort of 1,209 patients were followed to the date of death or first adverse cardiac event up to 1 year after CPC admission. Cardiac events were defined as coronary artery bypass graft, percutaneous transluminal coronary angioplasty, cardiogenic shock, cardiac-related death, congestive heart failure admission, ventricular tachycardia/ventricular fibrillation arrest, and myocardial infarction. Patients with acute ST-segment elevation or depression of >1 mm, positive enzyme (creatine kinase myocardial band) testing, or unstable angina during their CPC evaluation were admitted without GXT testing. Statistical analysis included chi-square test for complication rates and Cox proportional-hazards modeling. Nine hundred fifty-eight of 1,209 patients underwent GXT testing. Patients with positive, inconclusive, and normal GXTs had complication rates of 36.8% (7 of 19), 3.4% (9 of 267), and 1.1% (5 of 456), respectively. After adjusting for age, sex, and race, the relative risk of complication was 38.9 (95% confidence interval 11.7 to 129.6) with a positive GXT, and 3.6 (95% confidence interval 1.2 to 10.7) with an inconclusive GXT compared with a normal GXT. The GXT is a good prognostic indicator of adverse cardiac events in low- to moderate-risk chest pain in patients evaluated in an emergency department CPC.     

Comparison of early dobutamine stress echocardiography and exercise electrocardiographic testing for management of patients presenting to the emergency department with chest pain

This study compared the cost-effectiveness of dobutamine-atropine stress echocardiography (DASE) and electrocardiographic exercise testing (EET) implemented in emergency department accelerated diagnostic protocols for the early stratification of low-risk patients presenting with acute chest pain (ACP). One hundred ninety-nine patients with ACP, nondiagnostic electrocardiographic results, and negative biomarker results were randomized to DASE (n = 110) or EET (n = 89) <6 hours after emergency department presentation. Patients with negative risk assessment results were immediately discharged and followed for 2 months. Ninety patients (82%) in the DASE arm and 78 (88%) in the EET arm were discharged after the diagnosis of nonischemic ACP. The mean lengths of stay in the hospital were 23 +/- 12 and 31 +/- 23 hours in the DASE and EET arms, respectively (p = 0.01). No 2-month follow-up events occurred in DASE patients, and the event rate was significantly higher in EET patients (0% vs 11%, p = 0.004). The DASE strategy showed lower costs compared with the EET strategy at 1-month ($1,026 +/- $250 vs $1,329 +/- $1,288, p = 0.03) and 2-month ($1,029 +/- 253 vs $1,684 +/- $2,149, p = 0.005) follow-up. In conclusion, early DASE in emergency department triage of low-risk patients with ACP is safe and reduces costs of care compared to EET.     

Value of definitive diagnostic testing in the evaluation of patients presenting to the emergency department with chest pain

The optimal diagnostic evaluation of patients presenting to the emergency department (ED) with chest pain but without myocardial infarction or unstable angina is controversial. We performed a prospective, nonrandomized, observational study of 1,195 consecutive patients presenting to the ED with chest pain but who had normal or nondiagnostic electrocardiograms and negative cardiac biomarkers. Patients (mean ± SD age 61 ± 15 years; 55% women) were admitted to the hospital and a standard protocol for evaluation and treatment was suggested. The use of stress myocardial perfusion imaging (MPI) or cardiac catheterization during their index hospitalization, and the 3-month incidence of coronary angiography, percutaneous cardiac intervention, coronary artery bypass surgery, re-presentation to our institution’s ED for chest pain, myocardial infarction, or death were followed. Five hundred nine of 1,195 patients (43%) underwent provocative stress MPI during their index hospitalization; 37% had perfusion defects (predominantly ischemia). Fifty-six of 1,195 patients (4%) underwent cardiac catheterization without stress MPI for their primary diagnostic evaluation. Six hundred thirty of 1,195 patients (53%) had neither MPI or cardiac catheterization during their index hospitalization. During the 3-month follow-up period, patients with a normal stress perfusion study during their index hospitalization had fewer return visits (4%) compared with patients with abnormal perfusion studies (19%), those who underwent catheterization directly (16%), or patients with no initial diagnostic evaluation (15%) (p <0.001). In addition, patients who had a diagnostic evaluation during their index hospitalization had a lower incidence of either acute myocardial infarction (0.9% vs 2.1%) or death (0.4% vs 3.0%, p <0.001) in the 3-month follow-up period. Accordingly, we strongly advocate provocative stress MPI early after presentation for chest pain in all patients with risk factors for coronary artery disease.     

Underuse and overuse of diagnostic testing for coronary artery disease in patients presenting with new-onset chest pain

PURPOSE: To determine the extent of overuse and underuse of diagnostic testing for coronary artery disease and whether the socioeconomic status, health insurance, gender, and race/ethnicity of a patient influences the use of diagnostic tests. SUBJECTS AND METHODS: We identified patients who presented with new-onset chest pain not due to myocardial infarction at one of five Los Angeles-area hospital emergency departments between October 1994 and April 1996. Explicit criteria for diagnostic testing were developed using the RAND/University of California, Los Angeles, expert panel method. They were applied to data collected by medical record review and patient questionnaire. RESULTS: Of the 356 patients, 181 met necessity criteria for diagnostic cardiac testing. Of these, 40 (22%) failed to receive necessary tests. Only 7 (3%) of the 215 patients who received some form of cardiac testing had tests that were judged to be inappropriate. Underuse was significantly more common in patients with only a high school education (30% vs 15% for those with some college, P = 0.02) and those without health insurance (34% vs 15% of insured patients, P = 0.01). In a multivariate logistic regression model, only the lack of a post-high school education was a significant predictor of underuse (odds ratio 2.2, 95% confidence interval 1.0 to 4.4). CONCLUSION: Among patients with new-onset chest pain, underuse of diagnostic testing for coronary artery disease was much more common than overuse. Underuse was primarily associated with lower levels of patient education.     

Newer imaging methods for triaging patients presenting to the emergency department with chest pain

The usefulness of electron beam CT (EBCT) for the risk stratification of patients in the emergency department (ED) who have possible acute coronary syndrome has been evaluated in three small studies. The results of these studies are promising, as patients who have no coronary calcium detected by EBCT essentially had no adverse cardiac events. Although the negative predictive value of EBCT was excellent, the limited positive predictive value that would lead to further diagnostic testing makes this strategy less attractivei f applied to a broad population. Further larger studies may help define which patients in the ED who have chest pain and nondiagnostic ECGs can be effectively evaluated by EBCT. Recent advances in noninvasive coronary angiography by multislice computed tomography are of considerable interest in the ED evaluation of patients with undefined chest pain, but the utility of this method in this setting awaits clinical studies.     

Diagnostic testing of the emergency department patient with chest pain

In evaluating patients with nondiagnostic initial clinical or electrocardiogram (ECG) findings for acute cardiac ischemia, continuous 12-lead ECG monitoring increases the detection of diagnostic ECG findings, including ST-segment elevation, in patients awaiting hospital admission. Rest scanning with technitium-99m sestamibi is able to risk stratify low-moderate risk patients into lower and higher risk groups for cardiac events. Caveats include the reduced sensitivity of scanning of patients who are pain free and the need for follow-up exercise scans for patients free of perfusion defects at rest. Cardiac markers, particularly the troponins, show great promise for the detection of a larger part of the spectrum of acute coronary syndromes in the emergency department, including patients with minimal myocardial damage and higher risk for short-term death and nonfatal acute myocardial infarction. Accelerated diagnostic protocols using serial testing with cardiac markers, ECGs and then provocative testing over a 14-hour period, are feasible, safe, and cost-effective.     

Esophageal contribution to chest pain in patients with coronary artery disease

We conducted a prospective study to determine the role of the esophagus in causing chest pain in patients with established CAD on optimum therapy. Thirty-two men with documented CAD who complained of frequent and usually daily retrosternal chest pain were evaluated. Following a standard esophageal manometry and acid perfusion test, simultaneous two-channel ambulatory Holter monitor and esophageal pH record tests were performed for 24 hours. Fifty-three episodes of chest pain were documented in 20 patients; 11 patients were free of pain. Of the 20 patients who complained of chest pains, 17 (85 percent) demonstrated at least one episode of PPR, defined as a drop in distal esophageal pH to less than 4 within ten minutes before or after the onset chest pain. Episodes of asymptomatic GER were common. The correlation of PPR with chest pain was 70 percent (37/53 episodes) and of ischemic ECG changes with chest pain 13 percent (7/53); in the remaining, there was no correlation with either. Two patients demonstrated simultaneous PPR and ischemic ECG changes. Seventeen esophageal motility abnormalities were observed in 14 patients (45 percent). It is our conclusion that esophageal disorders contribute to chest pain in patients with documented CAD. In this group, GER plays a greater role than in those with normal coronary arteries. In addition, esophageal motility disorders are common in these patients. Esophageal testing can be undertaken safely in these patients.     

Proton pump inhibitors for patients with coronary artery disease associated with reduced chest pain, emergency department visits, and hospitalizations

BACKGROUND: Patients with coronary artery disease (CAD) presenting to an emergency department (ED) with chest pain are likely to undergo hospitalization as clinicians attempt to elucidate the etiology. HYPOTHESIS: We hypothesized that proton pump inhibitor (PPI) therapy is associated with reduced chest pain events and evaluations in patients with CAD. METHODS: A patient population from a veterans medical center with documented CAD was identified retrospectively, and chest pain episodes, ED visits, and hospitalizations for chest pain were prospectively followed over 2 years. Comparison of patient outcomes between PPI (+PPI) and nonuse of PPI therapy (-PPI) was determined. RESULTS: Of 415 male patients, average age 73.4 years, 23% utilized a PPI and 77% did not. Proton pump inhibitor therapy was associated with reduced chest pain episodes (11.8 vs. 26.2%, p = 0.002), ED visits (12.3 vs. 24.3%, p = 0.044), and hospitalizations (12.8 vs. 23.9%, p = 0.086). Relative reductions were 55, 49, and 46%, respectively, after 2 years. Numbers of adverse events were also decreased in the +PPI group of patients: 70% fewer occurrences of chest pain (p = 0.002, relative risk [RR] = 3.3), 55% fewer ED visits (p = 0.049, RR = 2.2), and 53% fewer hospitalizations (p = 0.064, RR = 2.1). By multivariate analysis, PPI therapy independently predicted reduced prevalence of patients experiencing chest pain, ED visits, or hospitalizations (odds ratio [OR] = 0.09 [0.04-0.21]; 0.15 [0.06-0.40]; 0.14 [0.05-0.40]; all p < 0.001). CONCLUSIONS: Proton pump inhibitor therapy for male patients with CAD from a veterans medical center was associated with reduced prevalence of chest pain, ED visits, and hospitalizations for chest pain and reduced incidence of these events.     

Triage decisions for emergency department patients with chest pain

OBJECTIVE: To determine whether physicians’ risk attitudes correlate with their triage decisions for emergency department patients with acute chest pain. DESIGN: Cohort. SETTING: The emergency department of a university teaching hospital. PATIENTS: Patients presenting to the emergency department with a chief complaint of acute chest pain. PHYSICIANS: All physicians who were primarily responsible for the emergency department triage of at least one patient with acute chest pain from July 1990 to July 1991. METHODS: The physicians’ risk attitudes were assessed by two methods: 1) a new, six-question risk-taking scale adapted from the Jackson Personality Index (JPI), and 2) the Stress from Uncertainty Scale (SUS). RESULTS: The physicians who had high risk-taking scores (“risk seekers”) admitted only 31% of the patients they evaluated, compared with admission rates of 44% for the medium scorers and 53% for the physicians who had low risk-taking scores (“risk avoiders”), p<0.001. After adjustment for clinical factors, the patients triaged by the risk-seeking physicians had half the odds of admission [odds ratio (OR) 0.51, 95% confidence interval (95% CI) 0.27 to 0.97], and the patients triaged by the risk-avoiding physicians had nearly twice the odds of admission (OR 1.83, 95% CI 1.10 to 3.03) of the patients triaged by the medium-risk scoring physicians. The SUS did not correlate significantly with admission rates. Of the 92 patients released home by the risk-seeking physicians, 91 (99%) were known to be alive four to six weeks afterwards and one was lost to follow-up; among the 66 patients released by the risk-avoiding physicians, 64 (97%) were known to be alive at four to six weeks, one was lost to follow-up, and one died of ischemic heart disease during a subsequent hospitalization (p=NS). CONCLUSIONS: The physicians’ risk attitudes as measured by a brief risk-taking scale correlated significantly with then-rates of admission for emergency department patients with acute chest pain. These data do not suggest that the risk-seeking physicians achieved lower admission rates by releasing more patients who needed to be in the hospital, but an adequate evaluation of the appropriateness of triage decisions of risk-seeking and risk-avoiding physicians will require further study.