Effectiveness and outcomes of a nurse practitioner-run chest pain evaluation unit.

BACKGROUND: Every year, more than 5 million patients seek medical care for chest pain. OBJECTIVE: The goal of this study was to evaluate test utilization and outcomes of a nurse practitioner (NP)-based chest pain unit and compare results to data previously reported from our institution. DESIGN, SETTING, AND PARTICIPANTS: The records from 814 consecutive patients with chest pain admitted to the NP-run unit were compared to the outcomes of 250 patients admitted to a separate hospitalist-run unit at a New York City hospital. RESULTS: Forty-four percent of patients in the NP unit underwent stress myocardial perfusion imaging (MPI) as the primary diagnostic test (compared to 22% in the hospitalist unit, p < .0001). The average length of stay was shorter for patients in the NP unit (2.7 ± 3.6 days compared to 3.9 ± 3.4 days, p < .0001). Additionally, the 90-day readmission rate was less for patients in the NP unit (2.7% vs. 3.9%, p < .0006). CONCLUSIONS: An NP-run chest pain unit resulted in decreased length of stay and reduced readmission rates compared to a hospitalist-based unit.

Mortality in the coronary care unit.

OBJECTIVES: Currently, there are limited data on mortality or predictors of survival for patients admitted to the coronary care unit (CCU). The purpose of this study was to provide data on mortality in the modern-day CCU and to better define factors influencing patient survival. METHODS: A survey was conducted of all patients admitted to CCUs in New York City metropolitan academic hospitals in 2011, followed by a retrospective analysis comparing clinical data from 59 nonsurvivors with those from 897 survivors at two representative institutions. RESULTS: The weighted average mortality in the CCU across all hospitals was 5.6% (range 2.2-9.2%). The average age of the patients admitted to the CCU was 67 years, with 68% being male. Acute coronary syndromes accounted for 57% of all CCU admissions. Survival was worse in patients admitted for cardiac arrest (P=0.000), sepsis (P=0.002), primary respiratory failure (P=0.031), and systolic heart failure (P=0.003). Excluding patients who were made 'do not resuscitate' during their CCU stay, patients receiving treatments such as defibrillation after in-CCU cardiac arrest, right heart invasive monitoring, mechanical ventilation, inotropic support, emergent dialysis, or placement of an intra-aortic balloon pump had higher rates of in-CCU mortality. The most frequent causes of death were intractable cardiogenic shock, brain death, respiratory failure, multiorgan failure, or hypotension. CONCLUSION: This study provides additional mortality information for the modern-day CCU and should help identify factors that may predict survival.

Identification of residual risk factors for the development of venous thromboembolism in medical inpatients receiving subcutaneous heparin therapy for prophylaxis.

OBJECTIVES: Venous thromboembolism (VTE) such as pulmonary embolism and deep venous thrombosis is the most common cause of preventable morbidity and mortality in hospitalized patients. Prophylaxis is recommended for medical patients older than 40 years with at least one risk factor. However, the currently recommended regimen prevents only about half of in-hospital VTE. The aim of this study was to identify the risk factors for development of VTE in medical inpatients who were already on recommended pharmacological prophylaxis. METHODS: We performed a retrospective cohort study of 10,633 patients who were admitted to the medicine service and received prophylaxis with subcutaneous unfractionated heparin. The diagnoses of pulmonary embolism and deep venous thrombosis were confirmed with computed tomography angiography and Doppler ultrasound, respectively. Univariate analysis with the χ(2)-test, followed by log-linear Poisson regression analysis was performed to determine the relative risk associated with each factor. RESULTS: Sixty cases of in-hospital VTE [raw incidence, 0.6%; 95% confidence interval (0.43-0.72)] were observed. On univariate analysis, a previous history of VTE or an active malignancy were found to be significant residual risk factors for the development of in-hospital VTE. On multivariate analysis, only a previous history of VTE remained a significant independent risk factor [relative risk=30.1; 95% confidence interval (17.1-53.0); P<0.0001]. CONCLUSION: Among hospitalized patients admitted to the medicine service and receiving VTE prophylaxis with subcutaneous unfractionated heparin, those with a previous history of VTE were at a significant risk of developing in-hospital VTE. This at-risk population should be considered for more aggressive therapy to prevent recurrent VTE.

Carotid plaque, compared with carotid intima-media thickness, more accurately predicts coronary artery disease events: a meta-analysis.

OBJECTIVES: We conducted the meta-analysis to compare the diagnostic accuracies of carotid plaque and carotid intima-media thickness (CIMT) measured by B-mode ultrasonography for the prediction of coronary artery disease (CAD) events. METHODS: Two reviewers independently searched electronic databases to identify relevant studies through April 2011. Both population-based longitudinal studies with the outcome measure of myocardial infarction (MI) events and diagnostic cohort studies for the detection of CAD were identified and analyzed separately. Weighted summary receiver-operating characteristic (SROC) plots, with pertinent areas under the curves (AUCs), were constructed using the Moses-Shapiro-Littenberg model. Meta-regression analyses, using parameters of relative diagnostic odds ratio (DOR), were conducted to compare the diagnostic performance after adjusting other study-specific covariates. RESULTS: The meta-analysis of 11 population-based studies (54,336 patients) showed that carotid plaque, compared with CIMT, had a significantly higher diagnostic accuracy for the prediction of future MI events (AUC 0.64 vs. 0.61, relative DOR 1.35; 95%CI 1.1-1.82, p=0.04). The 10-year event rates of MI after negative results were lower with carotid plaque (4.0%; 95% CI 3.6-4.7%) than with CIMT (4.7%; 95% CI 4.2-5.5%). The meta-analysis of 27 diagnostic cohort studies (4.878 patients) also showed a higher, but non-significant, diagnostic accuracy of carotid plaque compared with CIMT for the detection of CAD (AUC 0.76 vs. 0.74, p=0.21 for relative DOR). CONCLUSIONS: The present meta-analysis showed that the ultrasound assessment of carotid plaque, compared with that of CIMT, had a higher diagnostic accuracy for the prediction of future CAD events.

Effectiveness of Telemetry Guidelines in Predicting Clinically Significant Arrhythmias in Hospitalized Patients.

BACKGROUND: Cardiac rhythm monitoring is widely applied on hospitalized patients. However, its value has not been evaluated systematically. METHODS: This study considered the utility of our institutional telemetry guidelines in predicting clinically significant arrhythmias. A retrospective analysis was performed of 562 patients admitted to the telemetry unit. A total of 1932 monitoring days were evaluated. Patients were divided into 2 groups based on telemetry guidelines: "telemetry indicated" and "telemetry not indicated". RESULTS: Differences in arrhythmia event rates and pre-defined clinical significance were determined. One hundred and forty-four (34%) vs. 16 (11%) patients had at least one arrhythmic event in the "telemetry indicated" group compared with the "telemetry not indicated" group, respectively (P = 0.001). No patient in the "telemetry not indicated" group had a clinically significant arrhythmia. In contrast, of patients in the "telemetry indicated" group who had at least one arrhythmic event, 36% were considered clinically significant (P < 0.05). CONCLUSION: In conclusion, this study validates and supports the use of our institutional telemetry guidelines to allocate this resource appropriately and predict clinically significant arrhythmias.

Heparin-induced thrombocytopenia: analysis of risk factors in medical inpatients.

Heparin-induced thrombocytopenia (HIT) is an unpredictable reaction to heparin characterized by thrombocytopenia and increased risk of life-threatening venous and/or arterial thrombosis. Data are lacking regarding additional risk factors that may be associated with the development of HIT. This study aimed to identify the risk factors that may be associated with HIT in medical inpatients receiving heparin. Twenty five thousand six hundred and fifty-three patients admitted to the medicine service who received heparin product were reviewed retrospectively. The diagnosis of HIT was confirmed if the platelet count dropped >50% from baseline and there was a positive laboratory HIT assay. Fifty-five cases of in-hospital HIT were observed. Multivariate analysis identified the administration of full anticoagulation dose with unfractionated heparin or exposure to heparin products for more than 5 d with an increased risk of HIT. Moreover, patients who were on haemodialysis, carried a diagnosis of autoimmune disease, gout or heart failure were also at increased risk. The results suggest that when using heparin products in these patient cohorts, increased surveillance for HIT is necessary.

Fatty acid imaging of the heart.

Imaging metabolic processes in the human heart yields valuable insights into the mechanisms contributing to myocardial pathology and allows assessment of the efficacy of therapies designed to treat cardiac disease. Recent advances in fatty acid (FA) imaging using positron emission tomography (PET) include the development of a method to assess endogenous triglyceride metabolism and the design of new fluorine-18 labeled tracers. Studies of patients with diabetes have shown that the heart is resistant to insulin-mediated glucose uptake and that metabolism of nonesterified FA is upregulated. Cardiac PET imaging has also recently shown the increase in myocardial FA uptake seen in obese patients can be reversed with weight loss. And a pilot study of patients with chronic kidney disease demonstrated that PET imaging can reveal myocardial metabolic alterations that parallel the decline in estimated glomerular filtration rate. Recent advances in FA imaging using single photon emission computed tomography (SPECT) have been accomplished with the tracer ß-methyl-p-[(123)I]-iodophenyl-pentadecanoic acid (BMIPP). Two meta-analyses showed this imaging technique has a diagnostic accuracy for the detection of obstructive coronary artery disease that compares favorably with SPECT myocardial perfusion imaging and that BMIPP imaging yields excellent prognostic data in patients across the spectrum of coronary artery disease. A recent multicenter study of patients presenting with acute coronary syndromes found BMIPP SPECT imaging has greater diagnostic sensitivity than, and enhances the negative predictive value of, clinical assessment alone. Because of their exquisite sensitivity, nuclear imaging techniques facilitate the study of physiologic processes that are the key to our understanding of cardiac metabolism in health and disease.

No evidence of increased prevalence of premature coronary artery disease in New York City police officers as predicted by coronary artery calcium scoring.

OBJECTIVES: To investigate the prevalence of coronary artery disease (CAD) in active New York City police officers as detected by coronary artery calcium (CAC) scoring. METHODS: We assessed 2064 New York City police officers who underwent electron beam computed tomography for quantification of CAC. RESULTS: The mean age of study subjects was 42 +/- 6 years. A CAC score of 0 was present in 74% of men and 80% of women. A subset of 75 officers with known early exposure to World Trade Center dust were evaluated separately. CONCLUSION: New York City police officers do not have an increased prevalence of CAD compared with the general population as assessed with CAC scoring. At 5 years, exposure to World Trade Center dust does not appear to increase the risk of premature CAD.

Quantity of viable myocardium required to improve survival with revascularization in patients with ischemic cardiomyopathy: A meta-analysis.

BACKGROUND: This meta-analysis was conducted to determine optimal cutoff values for the assessment of viability using various imaging techniques for which revascularization would offer a survival benefit in patients with ischemic cardiomyopathy (ICM). METHODS AND RESULTS: We searched five electronic databases to identify relevant studies through December 2008. Relative risks of cardiac death, both in patients with and without viability, were calculated in each study. In order to estimate the optimal threshold for the presence of viability, we assumed a linear relationship between the amount of viable myocardium and survival benefit of revascularization. Twenty-nine studies (4,167 patients) met the inclusion criteria. The optimal threshold for the presence of viability was estimated to be 25.8% (95% CI: 16.6-35.0%) by positron emission tomography using 18F-fluorodeoxyglucose-perfusion mismatch, 35.9% (95% CI: 31.6-40.3%) by stress echocardiography using contractile reserve or ischemic responses, and 38.7% (95% CI: 27.7-49.7%) by single photon emission computed tomography using thallium-201 or technetium-99m MIBI myocardial perfusion. CONCLUSIONS: The calculated amount of viable myocardium determined to lead to improved survival was different among imaging techniques. Thus, separate cutoff values for imaging modalities may be helpful in determining which patients with ICM benefit from revascularization.

Prediction of future cardiovascular outcomes by flow-mediated vasodilatation of brachial artery: a meta-analysis.

BACKGROUND: We conducted a meta-analysis of observational studies which examined the association between flow-mediated dilatation (FMD) of brachial artery, a noninvasive measure of endothelial function, and future cardiovascular events. METHODS: Electronic databases were searched using a predefined search strategy. Data was independently abstracted on study characteristics, study quality, and outcomes by two reviewers. The multivariate relative risks, adjusted for confounding factors, were calculated from individual studies and then pooled using random-effects models. Statistical heterogeneity was evaluated using I2 statistics. Subgroup analyses and meta-regression analyses were conducted to assess the robustness of the meta-analysis. Publication bias was examined with funnel plot analysis and Egger's test. RESULTS: Four population-based cohort studies and ten convenience-cohort studies, involving 5,547 participants, were included in the meta-analysis. The pooled relative risks of cardiovascular events per 1% increase in brachial FMD, adjusted for confounding risk factors, was 0.87 (95% CI, 0.83- 0.91). The significant associations between brachial FMD and cardiovascular events were consistent among all subgroups evaluated, suggesting the robustness of the meta-analysis. However, the presence of heterogeneity in study quality, the remaining confounding factors, and publication bias in the available literature prevent a definitive evaluation of the additional predictive value of brachial FMD beyond traditional cardiovascular risk factors. CONCLUSIONS: The meta-analysis of heterogeneous studies with moderate methodological quality suggested that impairment of brachial FMD is significantly associated with future cardiovascular events. Further prospective randomized trials are warranted to confirm the efficacy of the usage of brachial FMD in the management of cardiovascular diseases.

Prognostic value of myocardial metabolic imaging with BMIPP in the spectrum of coronary artery disease: a systematic review.

BACKGROUND: We conducted a systematic review to summarize the current literature on the prognostic value of BMIPP imaging, fatty-acid metabolic imaging, for the prediction of cardiovascular events in coronary artery disease. METHODS AND RESULTS: Electronic databases (including Japanese medical literature search engines) were searched by a Japanese investigator using a predefined search strategy. Eleven studies, all conducted in Japan, were included in the meta-analysis. In three studies involving 541 patients with suspected acute coronary syndrome who were excluded for acute myocardial infarction (AMI), an abnormal finding on BMIPP imaging was significantly associated with future hard events (cardiac death or non-fatal myocardial infarction). The negative predictive value of BMIPP imaging for future hard events was 98.9% (96.8-99.7%) over 3.5 years. In six studies involving 542 patients with AMI, a larger defect on BMIPP imaging was significantly associated with future hard events. The prognostic value of perfusion-metabolism mismatch compared with myocardial perfusion imaging was dependent upon the relative timing of BMIPP imaging, revascularization, and myocardial perfusion damage. CONCLUSIONS: BMIPP imaging is useful for the risk stratification of patients with coronary artery disease, particularly patients with acute chest pain.

Impact of single or multicentre study design on the results of trials examining the efficacy of adjunctive devices to prevent distal embolisation during acute myocardial infarction.

AIMS: We investigated using meta-analytic techniques, whether, and to what degree, single or multicentre study design affects clinical outcomes in randomised controlled trials examining the efficacy of adjunctive devices to prevent distal embolisation during acute myocardial infarction (AMI). METHODS AND RESULTS: We searched electronic databases, conference proceedings, and internet-based sources of information to identify relevant studies through March 2009. The pooled summary effect was estimated with a random effects model. Subgroup and meta-regression analyses were conducted to examine the impact of single or multicentre design on trial outcomes compared with other variables. A total of 25 randomised trials (5,919 patients) were included in the analysis. The major sources of heterogeneity in trial outcomes were single or multicentre design, type of device used, study size, study region, and presence of conflicts of interest, of which the most influential source of heterogeneity was single or multicentre design (p-values of regression coefficient on meta-regression analyses were 0.09 for mortality, 0.001 for incomplete ST-segment resolution, and 0.07 for impaired myocardial blush grade, respectively). CONCLUSIONS: Single or multicentre study design has a significant impact on outcomes in trials examining the efficacy of adjunctive devices in AMI.

Telemetry monitoring guidelines for efficient and safe delivery of cardiac rhythm monitoring to noncritical hospital inpatients.

Telemetry monitoring is a limited resource in most hospitals. Few clinical studies have established firm criteria for inpatient telemetry. At our urban institution, we have developed and incorporated guidelines to identify patients who benefit from cardiac rhythm monitoring. These guidelines serve to minimize inappropriate use of telemetry beds, thereby preventing emergency department overcrowding and ambulance diversion. This improvement in efficiency is achieved without compromising health care.

Correlation of antecedent stress myocardial perfusion imaging with the infarct related artery in ST-elevation myocardial infarction.

BACKGROUND: While stress myocardial perfusion imaging (MPI) has strong prognostic power, it predicts the site of a subsequent acute myocardial infarction (AMI) in only 47-77% of patients. Prior studies have included small number of subjects and the interval between the stress test and the AMI has varied. The objective of the present study was to further evaluate the relationship between antecedent stress MPI and subsequent AMI. METHODS: We screened 600 patients admitted to our institution with acute ST-elevation MI and identified 21 patients who had a stress MPI an average of 4.8 months prior to the event. The location of perfusion defects on MPI were compared to the angiographic findings at the time of the subsequent AMI. RESULTS: Sixteen patients (76%) with AMI had defects on antecedent stress MPI while 5 patients (24%) had normal scans. Reversible or fixed perfusion defects in the territory corresponding to the site of AMI were seen in 62% of patients. All 5 patients with normal scans had multiple risk factors for coronary artery disease. CONCLUSION: Although a normal stress MPI portends an excellent outcome, a small proportion of patients with normal scans, but with risk factors go on to develop AMI. Stress MPI has reasonable power in predicting future STEMI, but a lesser degree for the location of the future MI. Complementary imaging approaches such as coronary calcium scoring or CT angiography may be beneficial in the assessment of patients at high risk for MI.

The role of heart-type fatty acid-binding protein in the diagnosis of acute coronary syndrome.

BACKGROUND: Heart-type fatty acid-binding protein (H-FABP) is a membrane-bound protein that facilitates transport of fatty acids from the blood into the heart. It is currently being used outside the United States for the early diagnosis of myocardial infarction (MI). However, previous studies have shown inconsistent correlation of H-FABP with standard cardiac biomarkers. METHODS: Fifty patients admitted with ST segment elevation MI (n=25), non-ST segment elevation MI (n=15) or unstable angina (n=10) were evaluated. The CardioDetect med cardiac infarction test (rennesens GmbH, Germany) was used to measure both qualitative and quantitative H-FABP. RESULTS: Of the 40 patients with acute MI, the initial troponin assay was positive in 35 patients (88%), the qualitative H-FABP assay was positive in 23 patients (58%) and the quantitative H-FABP assay was positive in 15 patients (38%) (P=0.001). No patient with MI had a positive H-FABP assay with a negative initial troponin assay. CONCLUSION: In the present study, the results of both the qualitative and quantitative H-FABP assays neither appeared earlier nor provided increased sensitivity compared with troponin in diagnosing acute MI. Accordingly, the use of H-FABP as a diagnostic tool for MI is limited.