Causes of prehospital misinterpretations of ST elevation myocardial infarction

Objectives: To determine the causes of software misinterpretation of ST elevation myocardial infarction (STEMI) compared to clinically identified STEMI to identify opportunities to improve prehospital STEMI identification. Methods: We compared ECGs acquired from July 2011 through June 2012 using the LIFEPAK 15 on adult patients transported by the Los Angeles Fire Department. Cases included patients ≥18 years who received a prehospital ECG. Software interpretation of the ECG (STEMI or not) was compared with data in the regional EMS registry to classify the interpretation as true positive (TP), true negative (TN), false positive (FP), or false negative (FN). For cases where classification was not possible using registry data, 3 blinded cardiologists interpreted the ECG. Each discordance was subsequently reviewed to determine the likely cause of misclassification. The cardiologists independently reviewed a sample of these discordant ECGs and the causes of misclassification were updated in an iterative fashion. Results: Of 44,611 cases, 50% were male (median age 65; inter-quartile range 52–80). Cases were classified as 482 (1.1%) TP, 711 (1.6%) FP, 43371 (97.2%) TN, and 47 (0.11%) FN. Of the 711 classified as FP, 126 (18%) were considered appropriate for, though did not undergo, emergent coronary angiography, because the ECG showed definite (52 cases) or borderline (65 cases) ischemic ST elevation, a STEMI equivalent (5 cases) or ST-elevation due to vasospasm (4 cases). The sensitivity was 92.8% [95% CI 90.6, 94.7%] and the specificity 98.7% [95% CI 98.6, 98.8%]. The leading causes of FP were ECG artifact (20%), early repolarization (16%), probable pericarditis/myocarditis (13%), indeterminate (12%), left ventricular hypertrophy (8%), and right bundle branch block (5%). There were 18 additional reasons for FP interpretation (<4% each). The leading causes of FN were borderline ST-segment elevations less than the algorithm threshold (40%) and tall T waves reducing the ST/T ratio below threshold (15%). There were 11 additional reasons for FN interpretation occurring ≤3 times each. Conclusion: The leading causes of FP automated interpretation of STEMI were ECG artifact and non-ischemic causes of ST-segment elevation. FN were rare and were related to ST-segment elevation or ST/T ratio that did not meet the software algorithm threshold

Volume-based referral for cardiovascular procedures in the United States: a cross-sectional regression analysis

BACKGROUND: We sought to estimate the numbers of patients affected and deaths avoided by adopting the Leapfrog Group's recommended hospital procedure volume minimums for coronary artery bypass graft (CABG) surgery and percutaneous coronary intervention (PCI). In addition to hospital risk-adjusted mortality standards, the Leapfrog Group recommends annual hospital procedure minimums of 450 for CABG and 400 for PCI to reduce procedure-associated mortality. METHODS: We conducted a retrospective analysis of a national hospital discharge database to evaluate in-hospital mortality among patients who underwent PCI (n = 2,500,796) or CABG (n = 1,496,937) between 1998 and 2001. We calculated the number of patients treated at low volume hospitals and simulated the number of deaths potentially averted by moving all patients to high volume hospitals under best-case conditions (i.e., assuming the full volume-associated reduction in mortality and the capacity to move all patients to high volume hospitals with no related harms). RESULTS: Multivariate adjusted odds of in-hospital mortality were higher for patients treated in low volume hospitals compared with high volume hospitals for CABG (OR 1.16, 95% CI 1.10–1.24) and PCI (OR 1.12, 95% CI 1.05–1.20). A policy of hospital volume minimums would have required moving 143,687 patients for CABG and 87,661 patients for PCI from low volume to high volume hospitals annually and prevented an estimated 619 CABG deaths and 109 PCI deaths. Thus, preventing a single death would have required moving 232 CABG patients or 805 PCI patients from low volume to high volume hospitals. CONCLUSION: Recommended hospital CABG and PCI volume minimums would prevent 728 deaths annually in the United States, fewer than previously estimated. It is unclear whether a policy requiring the movement of large numbers of patients to avoid relatively few deaths is feasible or effective

Association of Rapid Care Process Implementation on Reperfusion Times Across Multiple ST-Segment–Elevation Myocardial Infarction Networks

BACKGROUND: The Mission: Lifeline STEMI Systems Accelerator program, implemented in 16 US metropolitan regions, resulted in more patients receiving timely reperfusion. We assessed whether implementing key care processes was associated with system performance improvement. METHODS AND RESULTS: Hospitals (n=167 with 23 498 ST-segment-elevation myocardial infarction patients) were surveyed before (March 2012) and after (July 2014) program intervention. Data were merged with patient-level clinical data over the same period. For reperfusion, hospitals were grouped by whether a specific process of care was implemented, preexisting, or never implemented. Uptake of 4 key care processes increased after intervention: prehospital catheterization laboratory activation (62%-91%; P<0.001), single call transfer protocol from an outside facility (45%-70%; P<0.001), and emergency department bypass for emergency medical services direct presenters (48%-59%; P=0.002) and transfers (56%-79%; P=0.001). There were significant differences in median first medical contact-to-device times among groups implementing prehospital activation (88 minutes implementers versus 89 minutes preexisting versus 98 minutes nonimplementers; P<0.001 for comparisons). Similarly, patients treated at hospitals implementing single call transfer protocols had shorter median first medical contact-to-device times (112 versus 128 versus 152 minutes; P<0.001). Emergency department bypass was also associated with shorter median first medical contact-to-device times for emergency medical services direct presenters (84 versus 88 versus 94 minutes; P<0.001) and transfers (123 versus 127 versus 167 minutes; P<0.001). CONCLUSIONS: The Accelerator program increased uptake of key care processes, which were associated with improved system performance. These findings support efforts to implement regional ST-segment-elevation myocardial infarction networks focused on prehospital catheterization laboratory activation, single call transfer protocols, and emergency department bypass

Regional Systems of Care Demonstration Project: American Heart Association Mission: Lifeline STEMI Systems Accelerator.

BACKGROUND: Up to 50% of patients fail to meet ST-segment-elevation myocardial infarction (STEMI) guideline goals recommending a first medical contact-to-device time of <90 minutes for patients directly presenting to percutaneous coronary intervention-capable hospitals and <120 minutes for transferred patients. We sought to increase the proportion of patients treated within guideline goals by organizing coordinated regional reperfusion plans. METHODS: We established leadership teams, coordinated protocols, and provided regular feedback for 484 hospitals and 1253 emergency medical services (EMS) agencies in 16 regions across the United States. RESULTS: Between July 2012 and December 2013, 23 809 patients presented with acute STEMI (direct to percutaneous coronary intervention hospital: 11 765 EMS transported and 6502 self-transported; 5542 transferred). EMS-transported patients differed from self-transported patients in symptom onset to first medical contact time (median, 47 versus 114 minutes), incidence of cardiac arrest (10% versus 3%), shock on admission (11% versus 3%), and in-hospital mortality (8% versus 3%; P<0.001 for all comparisons). There was a significant increase in the proportion of patients meeting guideline goals of first medical contact-to-device time, including those directly presenting via EMS (50% to 55%; P<0.001) and transferred patients (44%-48%; P=0.002). Despite regional variability, the greatest gains occurred among patients in the 5 most improved regions, increasing from 45% to 57% (direct EMS; P<0.001) and 38% to 50% (transfers; P<0.001). CONCLUSIONS: This Mission: Lifeline STEMI Systems Accelerator demonstration project represents the largest national effort to organize regional STEMI care. By focusing on first medical contact-to-device time, coordinated treatment protocols, and regional data collection and reporting, we were able to increase significantly the proportion of patients treated within guideline goals

Hospital-level associations with 30-day patient mortality after cardiac surgery: a tutorial on the application and interpretation of marginal and multilevel logistic regression

Background: Marginal and multilevel logistic regression methods can estimate associations between hospital-level factors and patient-level 30-day mortality outcomes after cardiac surgery. However, it is not widely understood how the interpretation of hospital-level effects differs between these methods. Methods. The Australasian Society of Cardiac and Thoracic Surgeons (ASCTS) registry provided data on 32,354 patients undergoing cardiac surgery in 18 hospitals from 2001 to 2009. The logistic regression methods related 30-day mortality after surgery to hospital characteristics with concurrent adjustment for patient characteristics. Results: Hospital-level mortality rates varied from 1.0% to 4.1% of patients. Ordinary, marginal and multilevel regression methods differed with regard to point estimates and conclusions on statistical significance for hospital-level risk factors; ordinary logistic regression giving inappropriately narrow confidence intervals. The median odds ratio, MOR, from the multilevel model was 1.2 whereas ORs for most patient-level characteristics were of greater magnitude suggesting that unexplained between-hospital variation was not as relevant as patient-level characteristics for understanding mortality rates. For hospital-level characteristics in the multilevel model, 80% interval ORs, IOR-80%, supplemented the usual ORs from the logistic regression. The IOR-80% was (0.8 to 1.8) for academic affiliation and (0.6 to 1.3) for the median annual number of cardiac surgery procedures. The width of these intervals reflected the unexplained variation between hospitals in mortality rates; the inclusion of one in each interval suggested an inability to add meaningfully to explaining variation in mortality rates. Conclusions: Marginal and multilevel models take different approaches to account for correlation between patients within hospitals and they lead to different interpretations for hospital-level odds ratios. © 2012 Sanagou et al; licensee BioMed Central Ltd

Valvular regurgitation and surgery associated with fenfluramine use: an analysis of 5743 individuals

<p>Abstract</p> <p>Background</p> <p>Use of fenfluramines for weight loss has been associated with the development of characteristic plaques on cardiac valves causing regurgitation. However, previously published studies of exposure to fenfluramines have been limited by relatively small sample size, short duration of follow-up, and the lack of any estimate of the frequency of subsequent valvular surgery. We performed an observational study of 5743 users of fenfluramines examined by echocardiography between July 1997 and February 2004 in a single large cardiology clinic.</p> <p>Results</p> <p>The prevalence of at least mild aortic regurgitation (AR) or moderate mitral regurgitation (MR) was 19.6% in women and 11.8% in men (<it>p </it>< 0.0001 for gender difference). Duration of use was strongly predictive of mild or greater AR (<it>p </it>< 0.0001 for trend), MR (<it>p </it>= 0.002), and tricuspid regurgitation (TR) (<it>p </it>< 0.0001), as was earlier scan date (<it>p </it>< 0.0001 for those scanned prior to 1 January 2000 versus later). Increasing age was also independently associated with increased risk of AR and MR (both <it>p </it>< 0.0001). With mean follow-up of 30.3 months, AR worsened in 15.2%, remained the same in 63.1%, and improved in 21.7%. Corresponding values for MR were 24.8%, 47.4% and 27.9%. Pulmonary hypertension was strongly associated with MR but not AR. Valve surgery was performed on 38 patients (0.66% of 5743), 25 (0.44%) with clear evidence of fenfluramine-related etiology.</p> <p>Conclusion</p> <p>Regurgitant valvulopathy was common in individuals exposed to fenfluramines, more frequent in females, and associated with duration of use in all valves assessed. Valve surgery was performed as frequently for aortic as mitral valves and some tricuspid valve surgeries were also performed. The incidence of surgery appeared to be substantially increased compared with limited general population data.</p

Unplanned readmission rates, length of hospital stay, mortality, and medical costs of ten common medical conditions: a retrospective analysis of Hong Kong hospital data

<p>Abstract</p> <p>Background</p> <p>Studies on readmissions attributed to particular medical conditions, especially heart failure, have generally not addressed the factors associated with readmissions and the implications for health outcomes and costs. This study aimed to investigate the factors associated with 30-day unplanned readmission for 10 common conditions and to determine the cost implications.</p> <p>Methods</p> <p>This population-based retrospective cohort study included patients admitted to all public hospitals in Hong Kong in 2007. The sample consisted of 337,694 hospitalizations in Internal Medicine. The disease-specific risk-adjusted odd ratio (OR), length of stay (LOS), mortality and attributable medical costs for the year were examined for unplanned readmissions for 10 medical conditions, namely malignant neoplasms, heart diseases, cerebrovascular diseases, pneumonia, injury and poisoning, nephritis and nephrosis, diabetes mellitus, chronic liver disease and cirrhosis, septicaemia, and aortic aneurysm.</p> <p>Results</p> <p>The overall unplanned readmission rate was 16.7%. Chronic liver disease and cirrhosis had the highest OR (1.62, 95% confidence interval (CI) 1.39-1.87). Patients with cerebrovascular disease had the longest LOS, with mean acute and rehabilitation stays of 6.9 and 3.0 days, respectively. Malignant neoplasms had the highest mortality rate (30.8%) followed by aortic aneurysm and pneumonia. The attributed medical cost of readmission was highest for heart disease (US$3 199 418, 95$2 579 443-803 393).</p> <p>Conclusions</p> <p>Our findings showed variations in readmission rates and mortality for different medical conditions which may suggest differences in the quality of care provided for various medical conditions. In-hospital care, comprehensive discharge planning, and post-discharge community support for patients need to be reviewed to improve the quality of care and patient health outcomes.</p

Outcomes research in the development and evaluation of practice guidelines

BACKGROUND: Practice guidelines have been developed in response to the observation that variations exist in clinical medicine that are not related to variations in the clinical presentation and severity of the disease. Despite their widespread use, however, practice guideline evaluation lacks a rigorous scientific methodology to support its development and application. DISCUSSION: Firstly, we review the major epidemiological foundations of practice guideline development. Secondly, we propose a chronic disease epidemiological model in which practice patterns are viewed as the exposure and outcomes of interest such as quality or cost are viewed as the disease. Sources of selection, information, confounding and temporal trend bias are identified and discussed. SUMMARY: The proposed methodological framework for outcomes research to evaluate practice guidelines reflects the selection, information and confounding biases inherent in its observational nature which must be accounted for in both the design and the analysis phases of any outcomes research study