The use of syndromic surveillance for decision-making during the H1N1 pandemic: a qualitative study.

BACKGROUND: Although an increasing number of studies are documenting uses of syndromic surveillance by front line public health, few detail the value added from linking syndromic data to public health decision-making. This study seeks to understand how syndromic data informed specific public health actions during the 2009 H1N1 pandemic. METHODS: Semi-structured telephone interviews were conducted with participants from Ontario's public health departments, the provincial ministry of health and federal public health agency to gather information about syndromic surveillance systems used and the role of syndromic data in informing specific public health actions taken during the pandemic. Responses were compared with how the same decisions were made by non-syndromic surveillance users. RESULTS: Findings from 56 interviews (82% response) show that syndromic data were most used for monitoring virus activity, measuring impact on the health care system and informing the opening of influenza assessment centres in several jurisdictions, and supporting communications and messaging, rather than its intended purpose of early outbreak detection. Syndromic data had limited impact on decisions that involved the operation of immunization clinics, school closures, sending information letters home with school children or providing recommendations to health care providers. Both syndromic surveillance users and non-users reported that guidance from the provincial ministry of health, communications with stakeholders and vaccine availability were driving factors in these public health decisions. CONCLUSIONS: Syndromic surveillance had limited use in decision-making during the 2009 H1N1 pandemic in Ontario. This study provides insights into the reasons why this occurred. Despite this, syndromic data were valued for providing situational awareness and confidence to support public communications and recommendations. Developing an understanding of how syndromic data are utilized during public health events provides valuable evidence to support future investments in public health surveillance.

Perceived usefulness of syndromic surveillance in Ontario during the H1N1 pandemic.

BACKGROUND: Despite the growing popularity of syndromic surveillance, little is known about if or how these systems are accepted, utilized and valued by end users. This study seeks to describe the use of syndromic surveillance systems in Ontario and users' perceptions of the value of these systems within the context of other surveillance systems. METHODS: Ontario's 36 public health units, the provincial ministry of health and federal public health agency completed a web survey to identify traditional and syndromic surveillance systems used routinely and during the pandemic and to describe system attributes and utility in monitoring pandemic activity and informing decision-making. RESULTS: Syndromic surveillance systems are used by 20/38 (53%) organizations. For routine surveillance, laboratory, integrated Public Health Information System and school absenteeism data are the most frequently used sources. Laboratory data received the highest ratings for reliability, timeliness and accuracy ('very acceptable' by 92, 51 and 89%). Hospital/clinic screening data were rated as the most reliable and timely syndromic data source (50 and 43%) and ED visit data the most accurate (48%). During the pandemic, laboratory data were considered the most useful for monitoring the epidemiology and informing decision-making while ED screening and visit data were considered the most useful syndromic sources. CONCLUSIONS: End user perceptions are valuable for identifying opportunities for improvement and guiding further investments in public health surveillance.

A citywide protocol for primary PCI in ST-segment elevation myocardial infarction.

BACKGROUND: If primary percutaneous coronary intervention (PCI) is performed promptly, the procedure is superior to fibrinolysis in restoring flow to the infarct-related artery in patients with ST-segment elevation myocardial infarction. The benchmark for a timely PCI intervention has become a door-to-balloon time of less than 90 minutes. Whether regional strategies can be developed to achieve this goal is uncertain. METHODS: We developed an integrated-metropolitan-area approach in which all patients with ST-segment elevation myocardial infarction were referred to a specialized center for primary PCI. We sought to determine whether there was a difference in door-to-balloon times between patients who were referred directly from the field by paramedics trained in the interpretation of electrocardiograms and patients who were referred by emergency department physicians. RESULTS: Between May 1, 2005, and April 30, 2006, a total of 344 consecutive patients with ST-segment elevation myocardial infarction were referred for primary PCI: 135 directly from the field and 209 from emergency departments. Primary PCI was performed in 93.6% of patients. The median door-to-balloon time was shorter in patients referred from the field (69 minutes; interquartile range, 43 to 87) than in patients needing interhospital transfer (123 minutes; interquartile range, 101 to 153; P<0.001). Door-to-balloon times of less than 90 minutes were achieved in 79.7% of patients who were transferred from the field and in 11.9% of those transferred from emergency departments (P<0.001). CONCLUSIONS: Guideline door-to-balloon-times were more often achieved when trained paramedics independently triaged and transported patients directly to a designated primary PCI center than when patients were referred from emergency departments.

Comparison of early mortality of paramedic-diagnosed ST-segment elevation myocardial infarction with immediate transport to a designated primary percutaneous coronary intervention center to that of similar patients transported to the nearest hospital.

Speed of reperfusion is critical in ST-segment elevation myocardial infarction (STEMI). We assessed the safety and feasibility of an integrated metropolitan approach in which advanced-care paramedics interpret the prehospital electrocardiogram and independently refer patients with STEMI to a designated center for primary percutaneous coronary intervention (PCI). We developed and implemented a protocol in which paramedics trained in electrocardiographic interpretation bypassed the nearest emergency room and referred patients with suspected STEMI directly to a designated primary PCI center (paramedic-referred primary PCI). Outcomes of these patients were compared with those of a retrospective cohort of 225 consecutive patients with STEMI transported by ambulance to the nearest hospital emergency department. We treated 108 consecutive patients with STEMI using ambulance services according to the paramedic-referred primary PCI protocol. Primary PCI was performed in 93.5% versus 8.9% in the control group, and the median door-to-balloon time was 63 versus 125 minutes in the control group (p <0.0001 for 2 comparisons). Thrombolytic therapy was prescribed to 80.4% of the control group, with a median door-to-needle time of 41 minutes. In-hospital mortality was 1.9% in the paramedic-referred primary PCI group versus 8.9% in the control group (p = 0.017) and remained significantly lower after statistical adjustment for baseline risk. In conclusion, paramedic-referred primary PCI is a safe and feasible strategy for treating STEMI that is associated with rapid and effective reperfusion and very low in-hospital mortality.

Effect of exercise training on myocardial blood flow in patients with stable coronary artery disease.

BACKGROUND: The mechanisms by which exercise training benefits patients with coronary artery disease (CAD) are unclear but may include improved myocardial circulation. The aim of this study was to investigate the effect of exercise training on myocardial blood flow (MBF) and coronary flow reserve (CFR) in patients with stable CAD. METHODS: Twelve patients with documented CAD and ischemic ST-segment depression during exercise testing were randomized to exercise training (n = 7) or sedentary life style (control; n = 5) and underwent rubidium-82 positron emission tomography pre- and postintervention. Global left ventricle MBF and regional MBF in 17 left ventricular segments were calculated. Segments with <75% uptake (2 SD below normal) on stress uptake images were defined as abnormal. RESULTS: Exercise training increased global CFR by 20.8% +/- 27.9% versus control (10.5 +/- 24.1%, P = .0001). In normal segments (exercise training: n = 91; control: n = 46), exercise training did not change resting MBF (-14.1% +/- 16.3% vs -8.8% +/- 15.6%) and hyperemic MBF (-1.93% +/- 19.1% vs 2.86% +/- 20.5%, P = NS) and increased in CFR compared to control (17.0% +/- 25.5% vs 11.3% +/- 23.5%, P = .01). In abnormal segments, the change in resting MBF was not significantly different (-12.6% +/- 18.5% exercise [28 segments] vs -2.9% +/- 18.0% control [39 segments], P = NS). A significant increase was seen in hyperemic MBF with exercise (12.5% +/- 22.1% vs 2.6% +/- 16.3%, P = .02) and CFR (32.8% +/- 32.3% vs 9.5% +/- 24.8%, P = .001). CONCLUSIONS: Exercise training increased CFR in normal and diseased segments, and increased hyperemic flow in diseased segments. These data provide preliminary evidence in support of a favorable effect of exercise training on blood flow to ischemic myocardium.

Comparison of mortality patterns in patients with ST-elevation myocardial infarction arriving by emergency medical services versus self-transport (from the prospective Ottawa Hospital STEMI Registry).

Emergency medical services (EMSs) play a key role in the recognition and treatment of ST-elevation of myocardial infarction (STEMI). We sought to determine contemporary use of EMS in patients with STEMI and its relation to treatment, morbidity, and mortality patterns. Patients who arrived by EMS were compared with those who arrived by self-transport. Among 401 patients, 59.9% arrived by EMS and 40.1% by self-transport. Patients who arrived by EMS were older (p <0.001) and had higher Killip's scores (p <0.001). Door-to-needle and door-to-balloon intervals were shorter in patients who arrived by EMS (42 vs 57 minutes, p <0.001, and 124 vs 154 minutes, p <0.001, respectively). In-hospital mortality was higher in patients who used EMS (13.3% vs 5.0%, p <0.001). Patients who arrived by EMS also had higher mortality within the first hour of hospital arrival (4.2% vs 0%, p = 0.007). Multivariate analysis showed that only age and systolic blood pressure were predictors of mortality. Despite faster onset of reperfusion therapy in patients who arrived by EMS, mortality was higher. Almost 33% of these deaths occurred in the early in-hospital period, which was due to older and sicker patients having the tendency to come by EMS. Our results suggest that regional approaches are needed to trigger earlier reperfusion therapy in patients with STEMI who use EMS.

Diagnostic performance and potential clinical impact of advanced care paramedic interpretation of ST-segment elevation myocardial infarction in the field.

OBJECTIVES: Most studies of pre-hospital management of ST-elevation myocardial infarction (STEMI) have involved physicians accompanying the ambulance crew, or electrocardiogram (ECG) transmission to a physician at the base hospital. We sought to determine if Advanced Care Paramedics (ACPs) could accurately identify STEMI on the pre-hospital ECG and contribute to strategies that shorten time to reperfusion. METHODS: A STEMI tool was developed to: 1) measure the accuracy of the ACPs at diagnosing STEMI; and 2) determine the potential time saved if ACPs were to independently administer thrombolytic therapy. Using registry data, we subsequently estimated the time saved by initiating thrombolytic therapy in the field compared with in-hospital administration by a physician. RESULTS: Between August 2003 and July 2004, a correct diagnosis of STEMI on the pre-hospital ECG was confirmed in 63 patients. The performance of the ACPs in identifying STEMI on the ECG resulted in a sensitivity of 95% (95% confidence interval [CI] 86%-99%), a specificity of 96% (95% CI 94%-98%), a positive predictive value (PPV) of 82% (95% CI 71%-90%), and a negative predictive value (NPV) of 99% (95% CI 97%-100%). ACP performance for appropriately using thrombolytic therapy resulted in a sensitivity of 92% (95% CI 78%-98%), a specificity of 97% (95% CI 94%-98%), a PPV of 73% (95% CI 59%-85%) and an NPV of 99% (95% CI 97%-100%). We estimated that the median time saved by ACP administration of thrombolytic therapy would have been 44 minutes. CONCLUSIONS: ACPs can be trained to accurately interpret the pre-hospital ECG for the diagnosis of STEMI. These results are important for the design of regional integrated programs aimed at reducing delays to reperfusion.

Combined angioplasty and pharmacological intervention versus thrombolysis alone in acute myocardial infarction (CAPITAL AMI study).

OBJECTIVES: We compared a strategy of tenecteplase (TNK)-facilitated angioplasty with one of TNK alone in patients presenting with high-risk ST-segment elevation myocardial infarction (STEMI). BACKGROUND: Previous trials show that thrombolysis followed by immediate angioplasty for the treatment of STEMI does not improve ischemic outcomes compared with thrombolysis alone and is associated with excessive bleeding complications. Since the publication of these trials, however, significant pharmacological and technological advances have occurred. METHODS: We randomized 170 patients with high-risk STEMI to treatment with TNK alone (84 patients) or TNK-facilitated angioplasty (86 patients). The primary end point was a composite of death, reinfarction, recurrent unstable ischemia, or stroke at six months. RESULTS: At six months, the incidence of the primary end point was 24.4% in the TNK-alone group versus 11.6% in the TNK-facilitated angioplasty group (p = 0.04). This difference was driven by a reduction in the rate of recurrent unstable ischemia (20.7% vs. 8.1%, p = 0.03). There was a trend toward a lower reinfarction rate with TNK-facilitated angioplasty (14.6% vs. 5.8%, p = 0.07). No significant differences were observed in the rates of death or stroke. Major bleeding was observed in 7.1% of the TNK-alone group and in 8.1% of the TNK-facilitated angioplasty group (p = 1.00). CONCLUSIONS: In patients presenting with high-risk STEMI, TNK plus immediate angioplasty reduced the risk of recurrent ischemic events compared with TNK alone and was not associated with an increase in major bleeding complications.

Hospitalization costs of primary stenting versus thrombolysis in acute myocardial infarction: cost analysis of the Canadian STAT Study.

BACKGROUND: We previously showed that primary stenting was more effective than accelerated tPA in reducing the 6-month composite of death, reinfarction, stroke, or repeat revascularization for ischemia. This study looks at the hospitalization costs of primary stenting compared with accelerated tPA. METHODS AND RESULTS: Initial and 6-month hospitalization costs were computed for all patients randomly assigned to primary stenting (n=62) or accelerated tPA (n=61) in the Stenting versus Thrombolysis in Acute myocardial infarction Trial (STAT). Costs and resource usage were collected in detail for each patient. Physician fees were obtained directly from billings to the Ontario Health Insurance Plan. The length of initial hospitalization was 6.7+/-11.3 days in the stent group and 8.7+/-6.7 days in the tPA group (P<0.001). Total hospitalization days at 6 months were 8.3+/-13 days in the stent group and 12.1+/-14.0 days in the tPA group (P=0.001). Hospitalization costs were less in the stent group for the initial hospitalization, 6354 dollars +/-6382 versus 7893 dollars +/-4429 (P=0.001), and at 6 months, 7100 dollars +/-7111 versus 9559 dollars +/-6933 (P=0.001). CONCLUSIONS: In centers in which facilities and experienced interventionists are available, primary stenting is less costly and more effective than thrombolysis.

Prognostic use of cardiac troponin T and troponin I in patients with heart failure.

BACKGROUND: Troponin T (cTnT) and troponin I (cTnI) are present in the sera of some heart failure (HF) patients and have potential importance as prognostic markers. OBJECTIVE: To prospectively evaluate the prognostic value of cTnT and cTnI in well-characterized HF patients and clarify their relationship to other clinical markers of HF severity. METHODS: cTnT and cTnI were measured in 78 HF patients (45 inpatients, 33 outpatients) who were followed up prospectively for 12 months. RESULTS: Plasma cTnT (> or =0.02 ng/mL) and cTnI (> or =0.3 ng/mL) were detected in 51% and 46% of patients, respectively. These patients were more likely to be inpatients (70% versus 45% for cTnT, 75% versus 43% for cTnI, P<0.05 for both), have a higher plasma creatinine (153 versus 119 micromol/L for cTnT; 157 versus 118 micromol/L for cTnI, P<0.05) and lower plasma sodium (134 versus 138 mmol/L for both, P<0.05). At 12 months, they were more likely to have died or undergone cardiac transplantation (41% versus 14%, P=0.01 for cTnT; 43% versus 15%, P=0.004 for cTnI). After adjustment for New York Heart Association class, plasma sodium and inpatient status, a significant association with events was still evident for both troponins. CONCLUSIONS: Both cTnT and cTnI are strongly associated with other clinical indicators of HF severity and remain independent predictors of prognosis after adjustment for these factors. These results indicate a potential role for cTnT and cTnI in the clinical management of HF patients.