Deep cross-modal feature learning applied to predict acutely decompensated heart failure using in-home collected electrocardiography and transthoracic bioimpedance

BACKGROUND

Deep learning has been successfully applied to ECG data to aid in the accurate and more rapid diagnosis of acutely decompensated heart failure (ADHF). Previous applications focused primarily on classifying known ECG patterns in well-controlled clinical settings. However, this approach does not fully capitalize on the potential of deep learning, which directly learns important features without relying on a priori knowledge. In addition, deep learning applications to ECG data obtained from wearable devices have not been well studied, especially in the field of ADHF prediction.

METHODS

We used ECG and transthoracic bioimpedance data from the SENTINEL-HF study, which enrolled patients (≥21 years) who were hospitalized with a primary diagnosis of heart failure or with ADHF symptoms. To build an ECG-based prediction model of ADHF, we developed a deep cross-modal feature learning pipeline, termed ECGX-Net, that utilizes raw ECG time series and transthoracic bioimpedance data from wearable devices. To extract rich features from ECG time series data, we first adopted a transfer learning approach in which ECG time series were transformed into 2D images, followed by feature extraction using ImageNet-pretrained DenseNet121/VGG19 models. After data filtering, we applied cross-modal feature learning in which a regressor was trained with ECG and transthoracic bioimpedance. Then, we concatenated the DenseNet121/VGG19 features with the regression features and used them to train a support vector machine (SVM) without bioimpedance information.

RESULTS

The high-precision classifier using ECGX-Net predicted ADHF with a precision of 94 %, a recall of 79 %, and an F1-score of 0.85. The high-recall classifier with only DenseNet121 had a precision of 80 %, a recall of 98 %, and an F1-score of 0.88. We found that ECGX-Net was effective for high-precision classification, while DenseNet121 was effective for high-recall classification.

CONCLUSION

We show the potential for predicting ADHF from single-channel ECG recordings obtained from outpatients, enabling timely warning signs of heart failure. Our cross-modal feature learning pipeline is expected to improve ECG-based heart failure prediction by handling the unique requirements of medical scenarios and resource limitations.

HFSA/SAEM/ISHLT clinical expert consensus document on the emergency management of patients with ventricular assist devices

Mechanical circulatory support is now widely accepted as a viable long-term treatment option for patients with end-stage heart failure (HF). As the range of indications for the implantation of ventricular assist devices grows, so does the number of patients living in the community with durable support. Because of their underlying disease and comorbidities, in addition to the presence of mechanical support, these patients are at a high risk for medical urgencies and emergencies (Table 1). Thus, it is the responsibility of clinicians to understand the basics of their emergency care. This consensus document represents a collaborative effort by the Heart Failure Society of America, the Society for Academic Emergency Medicine, and the International Society for Heart and Lung Transplantation (ISHLT) to educate practicing clinicians about the emergency management of patients with ventricular assist devices. The target audience includes HF specialists and emergency medicine physicians, as well as general cardiologists and community-based providers.

An Emergency Medicine-focused Summary of the HFSA/SAEM/ISHLT Clinical Consensus Document on the Emergency Management of Patients With Ventricular Assist Devices

Mechanical circulatory support is increasingly used as a long-term treatment option for patients with end-stage heart failure. Patients with implanted ventricular assist devices are at high risk for a range of diverse medical urgencies and emergencies. Given the increasing prevalence of mechanical circulatory support devices, this expert clinical consensus document seeks to help inform emergency medicine and prehospital providers regarding the approach to acute medical and surgical conditions encountered in these complex patients.

Clinically significant ventricular arrhythmias and progression of depression and anxiety following an acute coronary syndrome

BACKGROUND

Depression and anxiety are common and associated with worse clinical outcomes in patients who experience an acute coronary syndrome (ACS). We investigated the association between major ventricular arrhythmias (VAs) with the progression of depression and anxiety among hospital survivors of an ACS.

METHODS

Patients were interviewed in hospital and by telephone up to 12 months after hospital discharge. The primary outcome was the presence of moderate/severe symptoms of depression and anxiety defined as a Patient Health Questionnaire (PHQ)-9 score ≥ 10 and a Generalized Anxiety Disorder (GAD)-7 score ≥ 10 at baseline and 1 month and PHQ-2 ≥ 3 and GAD-2 ≥ 3 at 3, 6, and 12 months. We used marginal models to examine the association between major VAs and the symptoms of depression or anxiety over time.

RESULTS

The average age of the study population (n = 2074) was 61.1 years, 33.5% were women, and 78.3% were white. VAs developed in 105 patients (5.1%). Symptoms of depression and anxiety were present in 22.2% and 23.5% of patients at baseline, respectively, and declined to 14.1% and 12.6%, respectively, at 1-month post-discharge. VAs were not significantly associated with the progression of symptoms of depression (adjusted relative risk [aRR] = 1.29, 95% confidence interval [CI] = 0.94-1.77) and anxiety (aRR = 1.22, 95% CI = 0.86-1.72), or with change in average scores of PHQ-2 and GAD-2 over time, both before and after risk adjustment.

CONCLUSION

The prevalence of symptoms of depression and anxiety was high after an ACS but declined thereafter and may not be associated with the occurrence of major in-hospital VAs.

Online health information seeking by adults hospitalized for acute coronary syndromes: Who looks for information, and who discusses it with healthcare providers?

OBJECTIVE

To describe characteristics associated with online health information-seeking and discussing resulting information with healthcare providers among adults with acute coronary syndromes (ACS).

METHODS

Consecutive patients hospitalized with ACS in 6 hospitals in Massachusetts and Georgia who reported Internet use in the past 4 weeks (online patients) were asked about online health information-seeking and whether they discussed information with healthcare providers. Participants reported demographic and psychosocial characteristics; clinical characteristics were abstracted from medical records. Logistic regression models estimated associations with information-seeking and provider communication.

RESULTS

Online patients (N = 1142) were on average aged 58.8 (SD: 10.6) years, 30.3% female, and 82.8% non-Hispanic white; 56.7% reported online health information-seeking. Patients with higher education and difficulty accessing medical care were more likely to report information-seeking; patients hospitalized with myocardial infarction, and those with impaired health numeracy and limited social networks were less likely. Among information-seekers, 33.9% discussed information with healthcare providers. More education and more frequent online information-seeking were associated with provider discussions.

CONCLUSION

Over half of online patients with ACS seek health information online, but only 1 in 3 of these discuss information with healthcare providers.

PRACTICE IMPLICATIONS

Clinician awareness of patient information-seeking may enhance communication including referral to evidence-based online resources.

Hyperglycemia and risk of ventricular tachycardia among patients hospitalized with acute myocardial infarction

Background

Little is known about the association of hyperglycemia with the development of ventricular tachycardia (VT) in patients hospitalized with acute myocardial infarction (AMI) which we examined in the present study. The objectives of this community-wide observational study were to examine the relation between elevated serum glucose levels at the time of hospital admission for AMI and occurrence of VT, and time of occurrence of VT, during the patient’s acute hospitalization.

Methods

We used data from a population-based study of patients hospitalized with AMI at all central Massachusetts medical centers between 2001 and 2011. Hyperglycemia was defined as a serum glucose level ≥ 140 mg/dl at the time of hospital admission. The development of VT was identified from physicians notes and electrocardiographic findings by our trained team of data abstractors.

Results

The average age of the study population was 70 years, 58.0% were men, and 92.7% were non-Hispanic whites. The mean and median serum glucose levels at the time of hospital admission were 171.4 mg/dl and 143.0, respectively. Hyperglycemia was present in 51.9% of patients at the time of hospital admission; VT occurred in 652 patients (15.8%), and two-thirds of these episodes occurred during the first 48 h after hospital admission (early VT). After multivariable adjustment, patients with hyperglycemia were at increased risk for developing VT (adjusted OR = 1.48, 95% CI = 1.23–1.78). The presence of hyperglycemia was significantly associated with early (multivariable adjusted OR = 1.39, 95% CI = 1.11–1.73) but not with late VT. Similar associations were observed in patients with and without diabetes and in patients with and without ST-segment elevation AMI.

Conclusions

Efforts should be made to closely monitor and treat patients who develop hyperglycemia, especially early after hospital admission, to reduce their risk of VT.

A Historical Perspective on Presentations of Hypertensive Acute Heart Failure

Background

Methods

Results

Conclusion

A Robust Motion Artifact Detection Algorithm for Accurate Detection of Heart Rates From Photoplethysmographic Signals Using Time-Frequency Spectral Features

Motion and noise artifacts (MNAs) impose limits on the usability of the photoplethysmogram (PPG), particularly in the context of ambulatory monitoring. MNAs can distort PPG, causing erroneous estimation of physiological parameters such as heart rate (HR) and arterial oxygen saturation (SpO2). In this study, we present a novel approach, "TifMA," based on using the time-frequency spectrum of PPG to first detect the MNA-corrupted data and next discard the nonusable part of the corrupted data. The term "nonusable" refers to segments of PPG data from which the HR signal cannot be recovered accurately. Two sequential classification procedures were included in the TifMA algorithm. The first classifier distinguishes between MNA-corrupted and MNA-free PPG data. Once a segment of data is deemed MNA-corrupted, the next classifier determines whether the HR can be recovered from the corrupted segment or not. A support vector machine (SVM) classifier was used to build a decision boundary for the first classification task using data segments from a training dataset. Features from time-frequency spectra of PPG were extracted to build the detection model. Five datasets were considered for evaluating TifMA performance: (1) and (2) were laboratory-controlled PPG recordings from forehead and finger pulse oximeter sensors with subjects making random movements, (3) and (4) were actual patient PPG recordings from UMass Memorial Medical Center with random free movements and (5) was a laboratory-controlled PPG recording dataset measured at the forehead while the subjects ran on a treadmill. The first dataset was used to analyze the noise sensitivity of the algorithm. Datasets 2-4 were used to evaluate the MNA detection phase of the algorithm. The results from the first phase of the algorithm (MNA detection) were compared to results from three existing MNA detection algorithms: the Hjorth, kurtosis-Shannon entropy, and time-domain variability-SVM approaches. This last is an approach recently developed in our laboratory. The proposed TifMA algorithm consistently provided higher detection rates than the other three methods, with accuracies greater than 95% for all data. Moreover, our algorithm was able to pinpoint the start and end times of the MNA with an error of less than 1 s in duration, whereas the next-best algorithm had a detection error of more than 2.2 s. The final, most challenging, dataset was collected to verify the performance of the algorithm in discriminating between corrupted data that were usable for accurate HR estimations and data that were nonusable. It was found that on average 48% of the data segments were found to have MNA, and of these, 38% could be used to provide reliable HR estimation.

Relation of Atrial Fibrillation in Acute Myocardial Infarction to In-Hospital Complications and Early Hospital Readmission

Atrial fibrillation (AF) is a common complication of acute myocardial infarction (AMI) and contributes to high rates of in-hospital adverse events. However, there are few contemporary studies examining rates of AF in the contemporary era of AMI or the impact of new-onset AF on key in-hospital and postdischarge outcomes. We examined trends in AF in 6,384 residents of Worcester, Massachusetts, who were hospitalized with confirmed AMI during 7 biennial periods between 1999 and 2011. Multivariate logistic regression analysis was used to examine associations between occurrence of AF and various in-hospital and postdischarge complications. The overall incidence of AF complicating AMI was 10.8%. Rates of new-onset AF increased from 1999 to 2003 (9.8% to 13.2%), and decreased thereafter. In multivariable adjusted models, patients developing new-onset AF after AMI were at a higher risk for in-hospital stroke (odds ratio [OR] 2.5, 95% confidence interval [CI] 1.6 to 4.1), heart failure (OR 2.0, 95% CI 1.7 to 2.4), cardiogenic shock (OR 3.7, 95% CI 2.8 to 4.9), and death (OR 2.3, 95% CI 1.9 to 3.0) than patients without AF. Development of AF during hospitalization for AMI was associated with higher rates of readmission within 30 days after discharge (21.7% vs 16.0%), but no significant difference was noted in early postdischarge 30-day all-cause mortality rates (8.3% vs 5.1%). In conclusion, new-onset AF after AMI is strongly related to in-hospital complications of AMI and higher short-term readmission rates.

Magnitude of and Prognostic Factors Associated With 1-Year Mortality After Hospital Discharge for Acute Decompensated Heart Failure Based on Ejection Fraction Findings

Background

Limited data exist about the magnitude of and the factors associated with prognosis within 1 year for patients discharged from the hospital after acute decompensated heart failure. Data are particularly limited from the more generalizable perspective of a population‐based investigation and should be further stratified according to currently recommended ejection fraction (EF) findings.

Methods and Results

The hospital medical records of residents of the Worcester, Massachusetts, metropolitan area who were discharged after acute decompensated heart failure from all 11 medical centers in central Massachusetts during 1995, 2000, 2002, 2004, and 2006 were reviewed. The average age of the 4025 study patients was 75 years, 93% were white, and 44% were men. Of these, 35% (n=1414) had reduced EF (≤40%), 13% (n=521) had borderline preserved EF (41–49%), and 52% (n=2090) had preserved EF (≥50%); at 1 year after discharge, death rates were 34%, 30%, and 29%, respectively (P=0.03). Older age, a history of chronic obstructive pulmonary disease, systolic blood pressure findings <150 mm Hg on admission, and hyponatremia were important predictors of 1‐year mortality for all study patients, whereas several comorbidities and physiological factors were differentially associated with 1‐year death rates in patients with reduced, borderline preserved, and preserved EF.

Conclusions

This population‐based study highlights the need for further contemporary research into the characteristics, treatment practices, natural history, and long‐term outcomes of patients with acute decompensated heart failure and varying EF findings and reinforces ongoing discussions about whether different treatment guidelines may be needed for these patients to design more personalized treatment plans.

PULSE-SMART: Pulse-Based Arrhythmia Discrimination Using a Novel Smartphone Application

BACKGROUND

Atrial fibrillation (AF) is a common and dangerous rhythm abnormality. Smartphones are increasingly used for mobile health applications by older patients at risk for AF and may be useful for AF screening.

OBJECTIVES

To test whether an enhanced smartphone app for AF detection can discriminate between sinus rhythm (SR), AF, premature atrial contractions (PACs), and premature ventricular contractions (PVCs).

METHODS

We analyzed two hundred and nineteen 2-minute pulse recordings from 121 participants with AF (n = 98), PACs (n = 15), or PVCs (n = 15) using an iPhone 4S. We obtained pulsatile time series recordings in 91 participants after successful cardioversion to sinus rhythm from preexisting AF. The PULSE-SMART app conducted pulse analysis using 3 methods (Root Mean Square of Successive RR Differences; Shannon Entropy; Poincare plot). We examined the sensitivity, specificity, and predictive accuracy of the app for AF, PAC, and PVC discrimination from sinus rhythm using the 12-lead EKG or 3-lead telemetry as the gold standard. We also administered a brief usability questionnaire to a subgroup (n = 65) of app users.

RESULTS

The smartphone-based app demonstrated excellent sensitivity (0.970), specificity (0.935), and accuracy (0.951) for real-time identification of an irregular pulse during AF. The app also showed good accuracy for PAC (0.955) and PVC discrimination (0.960). The vast majority of surveyed app users (83%) reported that it was "useful" and "not complex" to use.

CONCLUSION

A smartphone app can accurately discriminate pulse recordings during AF from sinus rhythm, PACs, and PVCs.

Detecting Heart Failure Decompensation by Measuring Transthoracic Bioimpedance in the Outpatient Setting: Rationale and Design of the SENTINEL-HF Study

Background

Recurrent hospital admissions are common among patients admitted for acute decompensated heart failure (ADHF), but identification of patients at risk for rehospitalization remains challenging. Contemporary heart failure (HF) management programs have shown modest ability to reduce readmissions, partly because they monitor signs or symptoms of HF worsening that appear late during decompensation. Detecting early stages of HF decompensation might allow for immediate application of effective HF therapies, thereby potentially reducing HF readmissions. One of the earliest indicators of HF decompensation is intrathoracic fluid accumulation, which can be assessed using transthoracic bioimpedance.

Objective

The SENTINEL-HF study is a prospective observational study designed to test a novel, wearable HF monitoring system as a predictor of HF decompensation among patients discharged after hospitalization for ADHF.

Methods

SENTINEL-HF tests the hypothesis that a decline in transthoracic bioimpedance, as assessed daily with the Philips fluid accumulation vest (FAV) and transmitted using a mobile phone, is associated with HF worsening and rehospitalization. According to pre-specified power calculations, 180 patients admitted with ADHF are enrolled. Participants transmit daily self-assessments using the FAV-mobile phone dyad for 45 days post-discharge. The primary predictor is the deviation of transthoracic bioimpedance for 3 consecutive days from a patient-specific normal variability range. The ADHF detection algorithm is evaluated in relation with a composite outcome of HF readmission, diuretic up-titration, and self-reported HF worsening (Kansas City Cardiomyopathy Questionnaire) during a 90-day follow-up period. Here, we provide the details and rationale of SENTINEL-HF.

Results

Enrollment in the SENTINEL-HF study is complete and the 90-days follow-up is currently under way. Once data collection is complete, the study dataset will be used to evaluate our ADHF detection algorithm and the results submitted for publication.

Conclusion

SENTINEL-HF emerged from our long-term vision that advanced home monitoring technology can improve the management of chronic HF by extending clinical care into patients’ homes. Monitoring transthoracic bioimpedance with the FAV may identify patients at risk of recurrent HF decompensation and enable timely preventive measures.

Trial Registration

Clinicaltrials.gov NCT01877369: https://clinicaltrials.gov/ct2/show/NCT01877369 (Archived by WebCite at http://www.webcitation.org/6bDYl0dGy)

Patient safety incident capture resulting from incident reports: a comparative observational analysis

BACKGROUND

Patient safety incident (PSI) discovery is an essential component of quality improvement. When submitted, incident reports may provide valuable opportunities for PSI discovery. However, little objective information is available to date to quantify or demonstrate this value. The objective of this investigation was to assess how often Emergency Department (ED) incident reports submitted by different sources led to the discovery of PSIs.

METHODS

A standardized peer review process was implemented to evaluate all incident reports submitted to the ED. Findings of the peer review analysis were recorded prospectively in a quality improvement database. A retrospective analysis of the quality improvement database was performed to calculate the PSI capture rates for incident reports submitted by different source groups.

RESULTS

363 incident reports were analyzed over a period of 18 months; 211 were submitted by healthcare providers (HCPs) and 126 by non-HCPs. PSIs were identified in 108 resulting in an overall capture rate of 31%. HCP-generated reports resulted in a 44% capture rate compared to 10% for non-HCPs (p < 0.001). There was no difference in PSI capture between sub-groups of HCPs and non-HCPs.

CONCLUSION

HCP-generated ED incident reports were much more likely to capture PSIs than reports submitted by non-HCPs. However, HCP reports still led to PSI discovery less than half the time. Further research is warranted to develop effective strategies to improve the utility of incident reports from both HCPs and non-HCPs.

Emergency department patient safety incident characterization: an observational analysis of the findings of a standardized peer review process

Background

Emergency Department (ED) care has been reported to be prone to patient safety incidents (PSIs). Improving our understanding of PSIs is essential to prevent them. A standardized, peer review process was implemented to identify and analyze ED PSIs. The primary objective of this investigation was to characterize ED PSIs identified by the peer review process. A secondary objective was to characterize PSIs that led to patient harm. In addition, we sought to provide a detailed description of the peer review process for others to consider as they conduct their own quality improvement initiatives.

Methods

An observational study was conducted in a large, urban, tertiary-care ED. Over a two-year period, all ED incident reports were investigated via a standardized, peer review process. PSIs were identified and analyzed for contributing factors including systems failures and practitioner-based errors. The classification system for factors contributing to PSIs was developed based on systems previously reported in the emergency medicine literature as well as the investigators’ experience in quality improvement and peer review. All cases in which a PSI was discovered were further adjudicated to determine if patient harm resulted.

Results

In 24 months, 469 cases were investigated, identifying 152 PSIs. In total, 188 systems failures and 96 practitioner-based errors were found to have contributed to the PSIs. In twelve cases, patient harm was determined to have resulted from PSIs. Systems failures were identified in eleven of the twelve cases in which a PSI resulted in patient harm.

Conclusion

Systems failures were almost twice as likely as practitioner-based errors to contribute to PSIs, and systems failures were present in the majority of cases resulting in patient harm. To effectively reduce PSIs, ED quality improvement initiatives should focus on systems failure reduction.

Photoplethysmograph signal reconstruction based on a novel hybrid motion artifact detection-reduction approach. Part I: Motion and noise artifact detection

Motion and noise artifacts (MNA) are a serious obstacle in utilizing photoplethysmogram (PPG) signals for real-time monitoring of vital signs. We present a MNA detection method which can provide a clean vs. corrupted decision on each successive PPG segment. For motion artifact detection, we compute four time-domain parameters: (1) standard deviation of peak-to-peak intervals (2) standard deviation of peak-to-peak amplitudes (3) standard deviation of systolic and diastolic interval ratios, and (4) mean standard deviation of pulse shape. We have adopted a support vector machine (SVM) which takes these parameters from clean and corrupted PPG signals and builds a decision boundary to classify them. We apply several distinct features of the PPG data to enhance classification performance. The algorithm we developed was verified on PPG data segments recorded by simulation, laboratory-controlled and walking/stair-climbing experiments, respectively, and we compared several well-established MNA detection methods to our proposed algorithm. All compared detection algorithms were evaluated in terms of motion artifact detection accuracy, heart rate (HR) error, and oxygen saturation (SpO2) error. For laboratory controlled finger, forehead recorded PPG data and daily-activity movement data, our proposed algorithm gives 94.4, 93.4, and 93.7% accuracies, respectively. Significant reductions in HR and SpO2 errors (2.3 bpm and 2.7%) were noted when the artifacts that were identified by SVM-MNA were removed from the original signal than without (17.3 bpm and 5.4%). The accuracy and error values of our proposed method were significantly higher and lower, respectively, than all other detection methods. Another advantage of our method is its ability to provide highly accurate onset and offset detection times of MNAs. This capability is important for an automated approach to signal reconstruction of only those data points that need to be reconstructed, which is the subject of the companion paper to this article. Finally, our MNA detection algorithm is real-time realizable as the computational speed on the 7-s PPG data segment was found to be only 7 ms with a Matlab code.

Decade-long trends in the magnitude, treatment, and outcomes of patients aged 30 to 54 years hospitalized with ST-segment elevation and non-ST-segment elevation myocardial infarction

Although acute myocardial infarction (AMI) occurs primarily in the elderly, this disease also affects young adults. Few studies have, however, presented data on relatively young patients hospitalized with AMI. The objectives of this population-based study were to examine recent trends in the magnitude, clinical characteristics, management, and in-hospital and long-term outcomes associated with ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation myocardial infarction (NSTEMI) in patients aged 30 to 54 years. We reviewed the medical records of 955 residents of the Worcester (Massachusetts) metropolitan area aged 30 to 54 years who were hospitalized for an initial STEMI or NSTEMI in 6 biennial periods from 1999 to 2009 at 11 greater Worcester medical centers. From 1999 to 2009, the proportion of young adults hospitalized with an STEMI decreased from approximately 2/3 to 2/5 of all patients with an initial AMI. Patients with STEMI were less likely to have a history of heart failure, hypertension, hyperlipidemia, and kidney disease than those with NSTEMI. Both groups received similar effective medical therapies during their acute hospitalization. In-hospital clinical complications and mortality were low and no significant differences in these end points were observed between patients with STEMI and NSTEMI or with regard to 1-year postdischarge death rates (1.9% vs 2.8%). The present results demonstrate recent decreases in the proportion of relatively young patients diagnosed with an initial STEMI. Patients with STEMI and NSTEMI had similar in-hospital outcomes and long-term survival. Trends in these and other important outcomes warrant continued monitoring.

Do immature platelet levels in chest pain patients presenting to the emergency department aid in the diagnosis of acute coronary syndrome?

INTRODUCTION

Early and accurate identification of acute coronary syndrome (ACS) vs. noncardiac chest pain in patients presenting to the emergency department (ED) is problematic and new diagnostic markers are needed. Previous studies reported that elevated mean platelet volume (MPV) is associated with ACS and predictive of cardiovascular risk. MPV is closely related to the immature platelet fraction (IPF), and recent studies have suggested that IPF may be a more sensitive marker of ACS than MPV. The objective of the present study was to determine whether the measurement of IPF assists in the diagnosis of ACS in patients presenting to the ED with chest pain.

METHODS

In this single-center, prospective, cross-sectional study, adult patients presenting to the ED with chest pain and/or suspected ACS were considered for enrollment. Blood samples from 236 ACS-negative and 44 ACS-positive patients were analyzed in a Sysmex XE-2100 for platelet count, MPV, IPF, and the absolute count of immature platelets (IPC).

RESULTS

Total platelet counts, MPV, IPF, and IPC were not statistically different between ACS-negative and ACS-positive patients. The IPF was 4.6 ± 2.7% and 5.0 ± 2.8% (mean ± SD, P = 0.24), and the IPC was 10.0 ± 4.6 and 11.5 ± 7.5 × 10(3) /μL (P = 0.27) for ACS-negative and ACS-positive patients, respectively.

CONCLUSION

In 280 patients presenting to the ED with chest pain and/or suspected ACS, no differences in IPF, IPC or MPV were observed in ACS-negative vs. ACS-positive patients, suggesting that these parameters do not assist in the diagnosis of ACS.

Point-of-care assessment of platelet reactivity in the emergency department may facilitate rapid rule-out of acute coronary syndromes: a prospective cohort pilot feasibility study

OBJECTIVE

Accurate, efficient and cost-effective disposition of patients presenting to emergency departments (EDs) with symptoms suggestive of acute coronary syndromes (ACS) is a growing priority. Platelet activation is an early feature in the pathogenesis of ACS; thus, we sought to obtain an insight into whether point-of-care testing of platelet function: (1) may assist in the rule-out of ACS; (2) may provide additional predictive value in identifying patients with non-cardiac symptoms versus ACS-positive patients and (3) is logistically feasible in the ED.

DESIGN

Prospective cohort feasibility study.

SETTING

Two urban tertiary care sites, one located in the USA and the second in Argentina.

PARTICIPANTS

509 adult patients presenting with symptoms of ACS.

MAIN OUTCOME MEASURES

Platelet reactivity was quantified using the Platelet Function Analyzer-100, with closure time (seconds required for blood, aspirated under high shear, to occlude a 150 µm aperture) serving as the primary endpoint. Closure times were categorised as 'normal' or 'prolonged', defined objectively as the 90th centile of the distribution for all participants enrolled in the study. Diagnosis of ACS was made using the standard criteria. The use of antiplatelet agents was not an exclusion criterion.

RESULTS

Closure times for the study population ranged from 47 to 300 s, with a 90th centile value of 138 s. The proportion of patients with closure times ≥138 s was significantly higher in patients with non-cardiac symptoms (41/330; 12.4%) versus the ACS-positive cohort (2/105 (1.9%); p=0.0006). The specificity of 'prolonged' closure times (≥138 s) for a diagnosis of non-cardiac symptoms was 98.1%, with a positive predictive value of 95.4%. Multivariate analysis revealed that the closure time provided incremental, independent predictive value in the rule-out of ACS.

CONCLUSIONS

Point-of-care assessment of platelet reactivity is feasible in the ED and may facilitate the rapid rule-out of ACS in patients with prolonged closure times.

Survival after hospital discharge for ST-segment elevation and non-ST-segment elevation acute myocardial infarction: a population-based study

Background

Limited recent data are available describing differences in long-term survival, and factors affecting prognosis, after ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation myocardial infarction (NSTEMI), especially from the more generalizable perspective of a population-based investigation. The objectives of this study were to examine differences in post-discharge prognosis after hospitalization for STEMI and NSTEMI, with a particular focus on factors associated with reduced long-term survival.

Methods

We reviewed the medical records of residents of the Worcester, MA, USA metropolitan area hospitalized at eleven central Massachusetts medical centers for acute myocardial infarction (AMI) during 2001, 2003, 2005, and 2007.

Results

A total of 3762 persons were hospitalized with confirmed AMI; of these, 2539 patients (67.5%) were diagnosed with NSTEMI. The average age of study patients was 70.3 years and 42.9% were women. Patients with NSTEMI experienced higher post-discharge death rates with 3-month, 1-year, and 2-year death rates of 12.6%, 23.5%, and 33.2%, respectively, compared to 6.1%, 11.5%, and 16.4% for patients with STEMI. After multivariable adjustment, patients with NSTEMI were significantly more likely to have died after hospital discharge (adjusted hazards ratio 1.28; 95% confidence interval 1.14–1.44). Several demographic (eg, older age) and clinical (eg, history of stroke) factors were associated with reduced long-term survival in patients with NSTEMI and STEMI.

Conclusions

The results of this study in residents of central Massachusetts suggest that patients with NSTEMI are at higher risk for dying after hospital discharge, and several subgroups are at particularly increased risk.

Early verification of myocardial ischemia with a novel biomarker of acute tissue damage: C-reactive protein fractional forms

BACKGROUND

We evaluated the utility of an independent biomarker of early ischemic cellular damage-circulating fractional forms of C-reactive protein (fracCRP), to verify the diagnostic relevance of low Troponin I (TnI) values within the context of a workup for Acute Coronary Syndrome (ACS).

METHODS

On a semi-preparative scale, the molecular characteristics of fracCRP were established by electron microscopy and Western Blot, using isolates captured from patient serum on phosphorylcholine beads and purified by size exclusion high-pressure liquid chromatography (SE-HPLC). Captured on an analytical scale, the diagnostic utility of fracCRP was evaluated in first-draw plasma specimens (total CRP not exceeding 6 mg/l) recovered from 300 cardiac emergency patients with final discharge diagnoses of ACS ruled out (N=132) or ruled in (N=168).

RESULTS

At a cutoff value chosen for 97.7% test specificity, the test metric (fracCRP×TnI) identified in the first blood draw 39.9% of all emergency patients ultimately diagnosed with ACS, and 17.9% of ultimately diagnosed patients who arrived with TnI values within the normal reference range (0.01-0.04 ng/ml).

CONCLUSIONS

These findings suggest that the fracCRP test metric could serve as a rule-in test for ACS in a significant proportion of low to moderate risk emergency patients.

Transporting without infusions: effect on door-to-needle time for acute coronary syndrome patients

BACKGROUND

Standard of care for patients with acute coronary syndrome/ST-segment elevation myocardial infarction (ACS/STEMI) is rapid revascularization of ischemic myocardium. Current optimal treatment is primary percutaneous coronary intervention (PCI) within 90 minutes after the patient accesses the health care system, and strategies to lower this time may improve outcomes.

OBJECTIVE

To compare interhospital transport times (TTs) before and after instituting a no-medication-infusion policy during transport of ACS patients. Our hypothesis was that transporting patients using only bolus medications would significantly reduce transport times without increasing hospital length of stay (LOS) or increasing mortality.

METHODS

We conducted an institutional review board (IRB)-approved retrospective chart review of all patients transferred from an outlying hospital to a primary PCI center using either critical care helicopter or ground transport. The study period was January 2006 through January 2008, with the policy of discontinuing infusions instituted in April 2007. The TT was calculated using departure and arrival times from dispatch logs. The LOS was determined via electronic medical record review. The TT and LOS differences were calculated using two-tailed t-tests with Welch's correction where appropriate. Results. A total of 154 ACS/STEMI transports were completed during the study period (74 before and 80 after policy initiation). The mean (+/- standard error of the mean) TT was 43.5 +/- 1.2 minutes before the policy and 37.1 +/- 0.9 minutes after the policy (p < 0.01). To specifically address different transport distances, we analyzed TTs from an identical group of referral hospitals in both the before- and after-policy groups. A significant reduction in TT remained in this after-policy group (TTs 43.5 +/- 1.2 minutes before the policy and 37.1 +/- 0.9 minutes after; p = 0.01). Data on LOS were available for 127 patients (58 patients before and 69 patients after) and averaged 4.6 +/- 0.8 days prior to the new policy and 3.9 +/- 0.4 days after (p = 0.41). Overall, only one patient died (after-policy group) (p = not significant).

CONCLUSIONS

A policy of transferring patients from one hospital directly to a cardiac catheterization laboratory using only bolus medications significantly reduces total door-to-needle time without adverse effects on LOS or mortality. Other institutions may want to consider such policies for interfacility transport of ACS patients.

Clinical features, treatment practices, and hospital and long-term outcomes of older patients hospitalized with decompensated heart failure: The Worcester Heart Failure Study

OBJECTIVES

To examine age-specific differences in clinical presentation, receipt of therapeutic practices and lifestyle recommendations, and hospital and long-term survival in patients hospitalized for acute heart failure HF.

DESIGN

Population-based study.

SETTING

The Worcester Heart Failure Study, a population-based study of residents of the a large Central New England metropolitan area hospitalized for decompensated HF at 11 greater-Worcester medical centers.

PARTICIPANTS

Four thousand five hundred thirty-four patients hospitalized for decompensated HF during 1995 and 2000.

MEASUREMENTS

Medical records were reviewed for demographic, clinical, and treatment characteristics and hospital survival status. Long-term follow-up of discharged hospital patients was conducted through 2005. Patients were compared according to four age groups (<65, 65-74, 75-84, and > or =85).

RESULTS

Mean age was 76; 24.0% were aged 85 and older. Patients aged 75 and older were more likely to be female and to have multiple comorbidities, a lower body mass index at the time of hospitalization, and higher ejection fraction findings. Older patients were significantly more likely to receive symptom-modifying medications and less likely to receive disease-modifying medications than younger patients. Older age was directly associated with higher in-hospital, 30-day, and 1-year death rates in crude and multivariable-adjusted analyses.

CONCLUSION

The results of this community-wide study suggest that clinical, treatment, and prognostic factors differ according to age in patients hospitalized for decompensated HF. These high-risk patients warrant special attention in future studies to improve their management and long-term survival.

’Postconditioning’ the human heart: Multiple balloon inflations during primary angioplasty may confer cardioprotection

Growing evidence from experimental models suggests that relief of myocardial ischemia in a stuttering manner (i.e., 'postconditioning' [PostC] with brief cycles of reperfusion-reocclusion) limits infarct size. However, the potential clinical efficacy of PostC has, to date,been largely unexplored. Using a retrospective study design, our aim was to test the hypothesis that creatine kinase release (CK: clinical surrogate of infarct size) would be attenuated in ST-segment elevation myocardial infarction (STEMI) patients requiring multiple balloon inflations-deflations during primary angioplasty versus STEMI patients who received minimal balloon inflations and/or direct stenting. To investigate this concept, we reviewed the records of all STEMI patients with single vessel occlusion who presented to our institution from November 2004 - April 2006 for primary angioplasty. Exclusion criteria were: previous MI, cardiogenic shock, patients resuscitated from cardiac arrest, or pre-infarct angina. Patients were prospectively divided into two subsets: those receiving 1-3 balloon inflations (considered the minimum range to achieve patency and stent placement) versus those in whom 4 or more inflations were applied. Peak CK release was significantly lower in patients requiring > or =4 versus 1-3 inflations (1655 versus 2272 IU/L; p<0.05), an outcome consistent with the concept that relief of sustained ischemia in a stuttered manner (analogous to postconditioning) may evoke cardioprotection in the clinical setting.

Postconditioning via stuttering reperfusion limits myocardial infarct size in rabbit hearts: role of ERK1/2

Emerging evidence suggests that restoration of blood flow in a stuttering manner may limit lethal myocardial ischemia-reperfusion injury. However, the mechanisms contributing to this phenomenon, termed postconditioning (post-C), remain poorly defined. Our aim was to test the hypothesis that activation of classic “survival kinases,” phosphatidylinositol 3-kinase (PI3-kinase) and/or extracellular signal-regulated kinase (ERK)1/2, may play a role in post-C-induced cardioprotection. In protocol 1, isolated buffer-perfused rabbit hearts underwent 30 min of sustained coronary artery occlusion and were randomized to receive abrupt reperfusion (controls) or four cycles of 30 s of reperfusion and 30 s of reocclusion before full restoration of flow (post-C). Protocol 2 was identical except control and postconditioned hearts received the PI3-kinase inhibitor LY-294002 ( protocol 2A) or the ERK1/2 antagonist PD-98059 ( protocol 2B) throughout the first 25 min of reperfusion, whereas in protocol 3, myocardial samples were obtained during the early minutes of reflow from additional control, postconditioned, and nonischemic sham hearts for the assessment, by standard immunoblotting, of phospho-Akt (downstream target of PI3-kinase) and phospho-ERK. Protocols 1 and 2 corroborated that infarct size (delineated by tetrazolium staining and expressed as a percent of risk region) was reduced in postconditioned hearts vs. control hearts and also revealed that post-C-induced cardioprotection was maintained despite LY-294002 treatment but was abrogated by PD-98059. These pharmacological data were supported by protocol 3, which showed increased immunoreactivity of phospho-ERK but not phospho-Akt with post-C. Thus our results implicate the involvement of ERK1/2 rather than PI3-kinase/Akt in the reduction of infarct size achieved with post-C.

Pretreatment with D-myo-inositol trisphosphate reduces infarct size in rabbit hearts: role of inositol trisphosphate receptors and gap junctions in triggering protection

Pretreatment with D-myo-inositol-1,4,5-trisphosphate hexasodium (D-myo-IP(3)), the sodium salt of the second messenger inositol 1,4,5-trisphosphate (IP(3)), is cardioprotective and triggers a reduction of infarct size comparable in magnitude to that obtained with ischemic preconditioning. However, this observation is enigmatic; whereas IP(3) signaling is conventionally initiated by receptor binding, IP(3) receptors are typically considered to be intracellular, and D-myo-IP(3) is membrane-impermeable. We propose that this paradox is explained by the presence of poorly characterized external IP(3) receptors and hypothesize that: 1) infarct size reduction with D-myo-IP(3) is receptor-mediated; and 2) communication via gap junctions and/or hemichannels is required to initiate this protection. To investigate the role of receptor binding, isolated buffer-perfused rabbit hearts underwent 30 min of coronary occlusion (CO) and 2 h of reflow. Prior to CO, hearts received no treatment (controls), D-myo-IP(3), L-myo-IP(3) (enantiomer not recognized by the IP(3) receptor), D-myo-IP(3) + the IP(3) receptor inhibitor xestospongin C (XeC), or XeC alone. Infarct size, assessed by tetrazolium staining, was reduced with D-myo-IP(3) treatment, whereas hearts that received L-myo-IP(3) or D-myo-IP(3) + XeC showed no protection. To evaluate the contribution of gap junctions/hemichannels, additional control and D-myo-IP(3)-treated cohorts received a 5-min infusion of heptanol or Gap 27, two structurally distinct gap junction inhibitors, administered at doses confirmed to attenuate intercellular transmission of a gap junction-permeable fluorescent dye. There was no infarct-sparing effect of D-myo-IP(3) in inhibitor-treated hearts. These data support the concepts that infarct size reduction with D-myo-IP(3) is triggered by receptor binding and that communication via gap junctions/hemichannels is involved in initiating this protection.

Brief apnea induces myocardial ischemic tolerance by an opioid-insensitive mechanism

BACKGROUND

Intermittent brief "preconditioning" (PC) ischemia has been shown to render the heart resistant to a subsequent sustained ischemic insult, in part through an opioid-dependent mechanism. Using the rabbit model, we tested the hypothesis that intermittent in vivo apnea elicits a cardioprotective response similar to that achieved with conventional PC ischemia. In addition, we sought to determine if infarct size reduction seen in this model was stimulated via opioid receptor activation.

METHODS

Anesthetized, intubated rabbits (n=35) were randomized to receive three 4.5-min bouts of apnea interspersed with 5 min normal ventilation or time-matched standard ventilation (controls). Upon completion of the in vivo PC/control period, the hearts were excised and assessed for ischemic tolerance on a modified Langendorff apparatus (40 min global ischemia+2h reperfusion). To assess the contribution of opioid receptor stimulation, two additional control and PC groups received the nonspecific opioid antagonist naloxone (10 mg/kg) prior to the in vivo intervention phase. Infarct size (delineated by tetrazoliam staining and expressed as a percentage of the left ventricle [LV]) was compared among the four groups by ANOVA.

RESULTS

Infarct size was significantly reduced in hearts that received antecedent apneic PC when compared with controls (63+/-5% vs. 34+/-8%) of the LV, respectively; P<.05). Pretreatment with naloxone had no significant effect on infarct size in nonpreconditioned hearts (80+/-6%) and did not inhibit the protective effects of apnea-induced PC (52+/-10% in naloxone+PC group).

CONCLUSIONS

Intermittent apnea evokes significant myocardial ischemic tolerance through an opioid-insensitive mechanism.

Cardioprotection 'outside the box'--the evolving paradigm of remote preconditioning

Conventional ischemic preconditioning is the phenomenon whereby brief episodes of myocardial ischemia render the ischemic territory resistant to a subsequent, sustained ischemic insult. A growing body of evidence further indicates that brief ischemia applied in distant organs and tissues can also protect naïve, virgin myocardium from ischemic injury. In this review, we describe the initial observations that provided the impetus for the study of 'remote preconditioning', and summarize our current knowledge of the three facets of 'preconditioning at a distance' --intra-cardiac, inter-organ and transferred inter-cardiac preconditioning.

Myocardial preconditioning factors evoke mesenteric ischemic tolerance via opioid receptors and K(ATP) channels

We have shown that a reverse-phase concentrate generated from the effluent of preconditioned (PC) rabbit hearts evokes a cardioprotective effect in virgin acceptor hearts. With the use of a model of sustained (1 h) simulated ischemia in isolated, spontaneously contracting rabbit jejunum, our current aims were to 1) determine whether protective factor(s) released from PC hearts can improve ischemic tolerance in noncardiac tissue; and 2) obtain preliminary insight into the mediator(s) involved in triggering and eliciting this remote protection. Recovery of contractile force following reoxygenation (our index of ischemic tolerance) was enhanced in jejunal segments pretreated with concentrate generated from PC hearts (33 +/- 3% of baseline, P < 0.01) versus segments that received no concentrate (21 +/- 2%) and segments treated with concentrate from normoxic hearts (16 +/- 3%; P < 0.01). Protection achieved with PC concentrate was attenuated by coadministration of naloxone or glibenclamide, thereby implicating the involvement of opioids and ATP-sensitive potassium channels. Moreover, evaluation of purified subfractions of the crude PC concentrate identified a specific bioactive fraction that may participate in triggering the improved jejunal ischemic tolerance.

Activator protein 1 activation following hypoosmotic stress in HepG2 cells is actin cytoskeleton dependent

BACKGROUND

Following hypoosmotic stress-induced cell volume change, the actin cytoskeleton reorganizes itself. The role of this reorganization in the activation of the phosphatidylinositol 3-OH-kinase/protein kinase B/activator protein 1 (PI-3-K/PKB/AP-1) proliferative signaling cascade is unknown. Focal adhesion kinase (FAK) participates in the cytoskeleton-based activation of PI-3-K. We hypothesized that hypoosmotic stress-induced activation of PKB and AP-1 in HepG2 cells is dependent on an intact actin cytoskeleton and subsequent FAK phosphorylation.

METHODS

HepG2 cells were incubated for 1 h with or without 20 microM cytochalasin D, an actin disrupter, and were then exposed for up to 30 min to hypoosmotic medium (200 mOsm/L) to induce swelling. Tumor necrosis factor alpha (1.4 nM) and medium alone served as positive and negative controls, respectively. Western blots measured cytoplasmic phosphorylated or total FAK and PKB. EMSAs measured nuclear AP-1. All experiments were performed in triplicate.

RESULTS

Exposure to hypoosmotic stress resulted in activation of the following signaling messengers in a sequential fashion: (1) phosphorylation of FAK occurred by 2 min, (2) phosphorylation of PKB occurred by 10 min, (3) nuclear translocation of AP-1 occurred by 30 min. All three signaling events were abolished when these cells were pretreated with cytochalasin D.

CONCLUSION

Actin reorganization following hypoosmotic stress is essential for the FAK-mediated activation of the PI-3-K/PKB/AP-1 proliferative cascade. These data delineate a possible mechanism by which the cell swelling-induced cytoskeletal changes can initiate proliferative signal transduction in human liver cancer.

Hypoosmotic stress stimulates growth in HepG2 cells via protein kinase B-dependent activation of activator protein-1

Although hypoosmotic stress-induced cell swelling activates phosphatidylinositol-3-kinase, its impact on the downstream signal protein kinase B and cell growth is unknown. Activator protein-1 is in part phosphatidylinositol-3-kinase dependent, and is important in proliferation. We hypothesized that cell swelling modulates proliferation in HepG2 cells via the protein kinase B-dependent activation of activator protein-1. HepG2 cells pretreated with or without LY294002 were exposed for up to 30 minutes to hypoosmotic medium (160 mOsm/L). Tumor necrosis factor-alpha (1.4 nmol/L) or normoosmolar medium (270 mOsm/L) served as positive and negative controls, respectively. Western immunoblots measured cytoplasmic phosphorylated and total protein kinase B. Electromobility shift assays measured nuclear activator protein-1. Methylene blue assays measured cell proliferation at 24, 48, and 72 hours after stimulation. Hypoosmotic stress phosphorylated protein kinase B by 10 minutes. Subsequently, hypoosmotic exposure stimulated activator protein-1 by 30 minutes. Pulse exposure to hypoosmotic stress potentiated HepG2 proliferation by 72 hours as compared to both negative controls and LY-inhibited cells (n = 4 per group, P = 0.009 and P = 0.004, respectively; P <0.001 analysis of variance. All three activation events were abolished with LY294002 pretreatment. In HepG2 cells, hypoosmotic stress-induced swelling stimulates proliferation via protein kinase B-mediated activation of activator protein-1. These data delineate a possible mechanism linking changes in cell volume to growth in human liver cancer.

Hypoosmotic stress activates p38, ERK 1 and 2, and SAPK/JNK in rat hepatocytes

BACKGROUND

Following hepatocyte injury, changes in the perihepatocyte milieu modulate cell volume and influence growth. Hypoosmotic stress activates nuclear factor-kappa B (NF-kappaB), a transcription factor believed to prime cell cycle progression in hepatocytes. In this study, we investigate the role of mitogen-activated protein kinases (MAPKs) in the activation of NF-kappaB.

MATERIALS AND METHODS

Quiescent primary hepatocytes were exposed to hypoosmotic serum-free William's E (WE) medium (200 mOsm/liter), with or without a 1-h pretreatment with either PD 98059 (15 microM) or SB 202190 (3 microM). Parallel experiments were conducted using hepatocyte growth factor (HGF) at 0.1 mg/ml and normoosmotic WE medium as positive and negative controls, respectively (n = 3). Relative densitometries of Western blots measured phosphorylated cytoplasmic p38, ERK 1 and 2, and SAPK/JNK. Electromobility shift assays examined nuclear NF-kappaB activation.

RESULTS

(i) Hypoosmolar WE medium phosphorylated p38, ERK 1 and 2, and SAPK/JNK by 5 min. (ii) Hypoosmolar WE medium activated NF-kappaB at 60 min. (iii) HGF phosphorylated all three MAPKs and activated NF-kappaB with profiles similar to those of hypoosmotic stress. (iv) Both PD 98059 and SB 202190 abrogated the activation of NF-kappaB in HGF-stimulated cells but not in hypoosmotically stressed cells.

CONCLUSION

(i) Both hypoosmotic cell swelling and HGF phosphorylate p38, ERK 1 and 2, and SAPK/JNK, and (ii) HGF, but not hypoosmotic stress, activates NF-kappaB via p38 and ERK 1 and 2 phosphorylation. These data suggest that cell swelling activates NF-kappaB through a pathway separate from that of growth factors.

Mesenteric and celiac duplex scanning: a validation study

PURPOSE

To validate the accuracy of previously established duplex ultrasound criteria for > or =50% superior mesenteric artery (SMA) and celiac artery (CA) stenosis by comparison with arteriography.

METHODS

Duplex criteria established retrospectively in our laboratory in 1991 identified an end-diastolic velocity (EDV) > or =45 cm/sec, or no flow signal, as highly sensitive (100%) and specific (92%) indicators for SMA stenosis > or =50% or occlusion. EDV was more accurate (95%) than peak systolic velocity (PSV), which had a maximal accuracy of 86% at a PSV > or =300 cm/sec, with low sensitivity (62%), but high specificity (100%). For CA, accurate velocity thresholds were not identified, but we subsequently noted that retrograde common hepatic artery flow direction from SMA collateral was highly predictive of severe CA stenosis or occlusion. Since publication of those findings, 243 mesenteric duplex scans were performed for clinical evaluation of suspected chronic mesenteric ischemia. Angiographic confirmation was available for a subset of 46. SMA and CA diameters were measured on lateral aortograms by observers blinded to the duplex results, and the original duplex diagnostic criteria were tested for accuracy. In addition, receiver operator characteristic curve analysis was performed on the velocity data to identify the most accurate velocity thresholds in the new data.

RESULTS

Duplex was technically adequate in 98% of SMA, 96% of CA, and 89% of hepatic arteries, and arteriograms were adequate in 100% of SMA and 98% of CA. For the SMA, EDV > or =45 cm/sec again provided the best sensitivity (90%), specificity (91%), positive predictive value (90%), negative predictive value (91%), and overall accuracy (91%). As in the retrospective study, PSV > or =300 cm/sec provided low overall accuracy (81%), low sensitivity (60%), but high specificity (100%). Lowering the PSV threshold improved sensitivity but reduced accuracy. For CA, retrograde common hepatic artery flow direction was 100% predictive of severe CA stenosis or occlusion. Velocity data in CA provided accuracy not found in the original study. EDV > or =55 cm/sec or no flow signal had best overall accuracy (95%) with high sensitivity (93%) and specificity (100%). PSV > or =200 cm/sec or no signal also had excellent accuracy (93%), sensitivity (93%), and specificity (94%). In addition, three of four anatomic anomalies were correctly identified by duplex. These included one right hepatic and one common hepatic artery originating from the SMA, and one common celiacomesenteric trunk.

CONCLUSION

This validation analysis confirms that duplex velocity criteria are accurate in the identification of mesenteric occlusive disease. Retrograde common hepatic artery flow direction correctly predicts severe CA stenosis or occlusion. Duplex ultrasound may also identify mesenteric anatomic variants that can influence study interpretation.