Preparation and Compression Resistance of Lightweight Concrete Filled with Lightweight Calcium Carbonate Reinforced Expanded Polystyrene Foam.

Lightweight concrete is widely used in the construction industry due to its low density and high strength. In this paper, lightweight concrete was prepared by a simple two-step method. Firstly, the light calcium carbonate reinforced epoxy macrospheres (LCR-EMS) material was obtained by adhering calcium lighter carbonate powder to the expanded polystyrene foam spheres (EPS) material using the "balling method". In the second step, the LCR-EMS was mixed with water, cement, and the hollow glass microspheres (HGMS) material using the "molding method" to obtain lightweight concrete. The combination of macroscopic photographs and microscopic morphology shows that the LCR-EMS material itself is uniformly encapsulated and well bonded to the matrix. Test results show that the density of the lightweight concrete decreases with an increase in the volume fraction of stacked LCR-EMS, the diameter, and the proportion of HGMS in the matrix, but it decreases with a decrease in the number of layers of LCR-EMS. The compressive strength of lightweight concrete exhibits a completely opposite trend. When three layers of LCR-EMS were used as filler material, the density and compressive strength of the concrete were 1.246 g/cm3 and 8.19 MPa, respectively. The density and maximum compressive strength of lightweight concrete were 1.146 g/cm3 and 6.37 Mpa, respectively, when filled with 8-9 mm-2L-90 svol% of LCR-EMS and 40 wt% of HGMS in the matrix. Compared with lightweight concrete filled with 90% EPS, the density increased by 20% while the compressive strength increased by 300%.

Intravascular Sono-Ablation for In-Stent Restenosis Relief: Transducer Development and the In-Vitro Demonstration.

OBJECTIVE: This study aimed to propose a new clinical modality for the relief of in-stent restenosis (ISR) using focused ultrasound (FUS) ablation. In the first research stage, a miniaturized FUS device was developed for the sonification of the remaining plaque after stenting, known as one of the causes of ISR. METHODS: This study presents a miniaturized (<2.8 mm) intravascular FUS transducer for ISR treatment. The performance of the transducer was predicted through a structural-acoustic simulation, followed by fabrication of the prototype device. Using the prototype FUS transducer, we demonstrated tissue ablation with bio-tissues over metallic stents, mimicking in-stent tissue ablation. Next, we conducted a safety test by detecting the existence of thermal damage to the arterial tissue upon sonication with a controlled dose. RESULTS: The prototype device successfully delivered sufficient acoustic intensity (>30 W/cm2) to a bio tissue (chicken breast) through a metallic stent. The ablation volume was approximately 3.9 × 7.8 × 2.6 mm3. Furthermore, 1.5 min sonication was sufficient to obtain an ablating depth of approximately 1.0 mm, not thermally damaging the underlying artery vessel. CONCLUSION: We demonstrated in-stent tissue sonoablation, suggesting it could be as a future ISR treatment modality. SIGNIFICANCE: Comprehensive test results provide a key understanding of FUS applications using metallic stents. Furthermore, the developed device can be used for sonoablation of the remaining plaque, providing a novel approach to the treatment of ISR.

North American COVID-19 Myocardial Infarction (NACMI) Risk Score for Prediction of In-Hospital Mortality.

Background: In-hospital mortality in patients with ST-segment elevation myocardial infarction (STEMI) is higher in those with COVID-19 than in those without COVID-19. The factors that predispose to this mortality rate and their relative contribution are poorly understood. This study developed a risk score inclusive of clinical variables to predict in-hospital mortality in patients with COVID-19 and STEMI. Methods: Baseline demographic, clinical, and procedural data from patients in the North American COVID-19 Myocardial Infarction registry were extracted. Univariable logistic regression was performed using candidate predictor variables, and multivariable logistic regression was performed using backward stepwise selection to identify independent predictors of in-hospital mortality. Independent predictors were assigned a weighted integer, with the sum of the integers yielding the total risk score for each patient. Results: In-hospital mortality occurred in 118 of 425 (28%) patients. Eight variables present at the time of STEMI diagnosis (respiratory rate of >35 breaths/min, cardiogenic shock, oxygen saturation of <93%, age of >55 â€‹years, infiltrates on chest x-ray, kidney disease, diabetes, and dyspnea) were assigned a weighted integer. In-hospital mortality increased exponentially with increasing integer risk score (Cochran-Armitage χ2, P â€‹< â€‹.001), and the model demonstrated good discriminative power (c-statistic â€‹= â€‹0.81) and calibration (Hosmer-Lemeshow, P â€‹= â€‹.40). The increasing risk score was strongly associated with in-hospital mortality (3.6%-60% mortality for low-risk and very high-risk score categories, respectively). Conclusions: The risk of in-hospital mortality in patients with COVID-19 and STEMI can be accurately predicted and discriminated using readily available clinical information.

A machine learning model in predicting hemodynamically significant coronary artery disease: A prospective cohort study.

Background: Coronary artery disease (CAD) costs healthcare billions of dollars annually and is the leading cause of death despite available noninvasive diagnostic tools. Objective: This study aims to examine the usefulness of machine learning in predicting hemodynamically significant CAD using routine demographics, clinical factors, and laboratory data. Methods: Consecutive patients undergoing cardiac catheterization between March 17, 2015, and July 15, 2016, at UNC Chapel Hill were screened for comorbidities and CAD risk factors. In this pilot, single-center, prospective cohort study, patients were screened and selected for moderate CAD risk (n = 185). Invasive coronary angiography and CAD prediction with machine learning were independently performed. Results were blinded from operators and patients. Outcomes were followed up for up to 90 days for major adverse cardiovascular and renal events (MACREs). Greater than 70% stenosis or a fractional flow reserve less than or equal to 0.8 represented hemodynamically significant coronary disease. A random forest model using demographic, comorbidities, risk factors, and lab data was trained to predict CAD severity. The Random Forest Model predictive accuracy was assessed by area under the receiver operating characteristic curve with comparison to the final diagnoses made from coronary angiography. Results: Hemodynamically significant CAD was predicted by 18-point clinical data input with a sensitivity of 81% ± 7.8%, and specificity of 61% ± 14.4% by the established model. The best machine learning model predicted a 90-day MACRE with specificity of 44.61% ± 14.39%, and sensitivity of 57.13% ± 18.70%. Conclusion: Machine learning models based on routine demographics, clinical factors, and lab data can be used to predict hemodynamically significant CAD with accuracy that approximates current noninvasive functional modalities.

Spatio-temporal hybrid neural networks reduce erroneous human "judgement calls" in the diagnosis of Takotsubo syndrome.

BACKGROUND: We investigate whether deep learning (DL) neural networks can reduce erroneous human "judgment calls" on bedside echocardiograms and help distinguish Takotsubo syndrome (TTS) from anterior wall ST segment elevation myocardial infarction (STEMI). METHODS: We developed a single-channel (DCNN[2D SCI]), a multi-channel (DCNN[2D MCI]), and a 3-dimensional (DCNN[2D+t]) deep convolution neural network, and a recurrent neural network (RNN) based on 17,280 still-frame images and 540 videos from 2-dimensional echocardiograms in 10 years (1 January 2008 to 1 January 2018) retrospective cohort in University of Iowa (UI) and eight other medical centers. Echocardiograms from 450 UI patients were randomly divided into training and testing sets for internal training, testing, and model construction. Echocardiograms of 90 patients from the other medical centers were used for external validation to evaluate the model generalizability. A total of 49 board-certified human readers performed human-side classification on the same echocardiography dataset to compare the diagnostic performance and help data visualization. FINDINGS: The DCNN (2D SCI), DCNN (2D MCI), DCNN(2D+t), and RNN models established based on UI dataset for TTS versus STEMI prediction showed mean diagnostic accuracy 73%, 75%, 80%, and 75% respectively, and mean diagnostic accuracy of 74%, 74%, 77%, and 73%, respectively, on the external validation. DCNN(2D+t) (area under the curve [AUC] 0·787 vs. 0·699, P = 0·015) and RNN models (AUC 0·774 vs. 0·699, P = 0·033) outperformed human readers in differentiating TTS and STEMI by reducing human erroneous judgement calls on TTS. INTERPRETATION: Spatio-temporal hybrid DL neural networks reduce erroneous human "judgement calls" in distinguishing TTS from anterior wall STEMI based on bedside echocardiographic videos. FUNDING: University of Iowa Obermann Center for Advanced Studies Interdisciplinary Research Grant, and Institute for Clinical and Translational Science Grant. National Institutes of Health Award (1R01EB025018-01).

Delayed Treatment of Acute Myocardial Infarction With Ventricular Septal Rupture Due to Patient Fear During the COVID-19 Pandemic.

During the coronavirus disease 2019 (COVID-19) pandmic, more patients are presenting with complications late after acute myocardial infarction. We report the case of a 71-year-old man who delayed seeking medical care for 2 weeks, despite progressive shortness of breath, cough, and tactile fever, for fear of contracting COVID-19 in the hospital. Clinical and echocardiographic evaluation revealed a ventricular septal rupture secondary to acute myocardial infarction. The patient underwent urgent cardiac catheterization, followed by successful saphenous vein grafting to the left anterior descending coronary artery and open surgical repair of the ventricular septal rupture with a bovine pericardial patch. This case highlights a potential long-lasting negative effect that the COVID-19 pandemic will have on the care-seeking behavior and health of patients with acute cardiovascular disease.

Prognostic value of shock index in patients admitted with non-ST-segment elevation myocardial infarction: the ARIC study community surveillance.

AIMS: Shock index (SI), defined as the ratio of heart rate (HR) to systolic blood pressure (SBP), is easily obtained and predictive of mortality in patients with ST-segment elevation myocardial infarction. However, large-scale evaluations of SI in patients with non-ST-segment elevation myocardial infarction (NSTEMI) are lacking. METHODS AND RESULTS: Hospitalizations for acute myocardial infarction were sampled from four US areas by the Atherosclerosis Risk in Communities (ARIC) study and classified by physician review. Shock index was derived from the HR and SBP at first presentation and considered high when ≥0.7. From 2000 to 2014, 18 301 weighted hospitalizations for NSTEMI were sampled and had vitals successfully obtained. Of these, 5753 (31%) had high SI (≥0.7). Patients with high SI were more often female (46% vs. 39%) and had more prevalent chronic kidney disease (40% vs. 32%). TIMI (Thrombolysis in Myocardial Infarction) risk scores were similar between the groups (4.3 vs. 4.2), but GRACE (Global Registry of Acute Coronary Syndrome) score was higher with high SI (140 vs. 118). Angiography, revascularization, and guideline-directed medications were less often administered to patients with high SI, and the 28-day mortality was higher (13% vs. 5%). Prediction of 28-day mortality by SI as a continuous measurement [area under the curve (AUC): 0.68] was intermediate to that of the GRACE score (AUC: 0.87) and the TIMI score (AUC: 0.54). After adjustments, patients with high SI had twice the odds of 28-day mortality (odds ratio = 2.02; 95% confidence interval: 1.46-2.80). CONCLUSION: The SI is easily obtainable, performs moderately well as a predictor of short-term mortality in patients hospitalized with NSTEMI, and may be useful for risk stratification in emergency settings.

Fibrinogen Levels and Bleeding Risk in Patients Undergoing Ultrasound-Assisted Catheter-Directed Thrombolysis for Submassive Pulmonary Embolism.

OBJECTIVES: We sought to test the hypothesis that patients undergoing ultrasound-assisted catheter-directed thrombolysis (USAT) with standard alteplase and heparin dosing would not develop significant depletion of systemic fibrinogen, which may account for the lower risk of bleeding seen in contemporary trials. We also sought to compare the relative outcomes of individuals with submassive pulmonary embolism (PE) undergoing USAT and anticoagulation alone. METHODS: Utilizing a single-center prospective registry, we identified 102 consecutive adult patients with submassive PE who were considered for USAT based on a standardized treatment algorithm between November 2016 and May 2019. Patients not receiving USAT therapy were treated with anticoagulation alone. RESULTS: Baseline characteristics were generally similar between groups (n = 51 in each group). Major bleeding rates were not significantly different between groups (2.0% vs 5.9% in USAT vs control, respectively; P=.62). Notably, no USAT patient experienced clinically significant hypofibrinogenemia (mean trough fibrinogen, 369.8 ± 127.1 mg/dL; minimum, 187 mg/dL). The mean trough fibrinogen of patients experiencing any bleeding event (major or minor) was 306.6 mg/dL (SE, 23.9 mg/dL) vs 380.3 mg/dL (SE, 20.4 mg/dL) in those without a bleeding event (P=.02). CONCLUSIONS: In this cohort analysis of patients undergoing USAT, there was no evidence for clinically significant depletion of fibrinogen or intracranial hemorrhage. Although our data suggest an association between lower fibrinogen levels and bleeding events, our results are not clear enough to suggest a clinically useful fibrinogen cut-off value. Further study is needed to determine the utility of routine fibrinogen monitoring in this population.

Recent Advances in Transducers for Intravascular Ultrasound (IVUS) Imaging.

As a well-known medical imaging methodology, intravascular ultrasound (IVUS) imaging plays a critical role in diagnosis, treatment guidance and post-treatment assessment of coronary artery diseases. By cannulating a miniature ultrasound transducer mounted catheter into an artery, the vessel lumen opening, vessel wall morphology and other associated blood and vessel properties can be precisely assessed in IVUS imaging. Ultrasound transducer, as the key component of an IVUS system, is critical in determining the IVUS imaging performance. In recent years, a wide range of achievements in ultrasound transducers have been reported for IVUS imaging applications. Herein, a comprehensive review is given on recent advances in ultrasound transducers for IVUS imaging. Firstly, a fundamental understanding of IVUS imaging principle, evaluation parameters and IVUS catheter are summarized. Secondly, three different types of ultrasound transducers (piezoelectric ultrasound transducer, piezoelectric micromachined ultrasound transducer and capacitive micromachined ultrasound transducer) for IVUS imaging are presented. Particularly, the recent advances in piezoelectric ultrasound transducer for IVUS imaging are extensively examined according to their different working mechanisms, configurations and materials adopted. Thirdly, IVUS-based multimodality intravascular imaging of atherosclerotic plaque is discussed. Finally, summary and perspectives on the future studies are highlighted for IVUS imaging applications.

Initial Findings From the North American COVID-19 Myocardial Infarction Registry.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has impacted many aspects of ST-segment elevation myocardial infarction (STEMI) care, including timely access to primary percutaneous coronary intervention (PPCI). OBJECTIVES: The goal of the NACMI (North American COVID-19 and STEMI) registry is to describe demographic characteristics, management strategies, and outcomes of COVID-19 patients with STEMI. METHODS: A prospective, ongoing observational registry was created under the guidance of 3 cardiology societies. STEMI patients with confirmed COVID+ (group 1) or suspected (person under investigation [PUI]) (group 2) COVID-19 infection were included. A group of age- and sex-matched STEMI patients (matched to COVID+ patients in a 2:1 ratio) treated in the pre-COVID era (2015 to 2019) serves as the control group for comparison of treatment strategies and outcomes (group 3). The primary outcome was a composite of in-hospital death, stroke, recurrent myocardial infarction, or repeat unplanned revascularization. RESULTS: As of December 6, 2020, 1,185 patients were included in the NACMI registry (230 COVID+ patients, 495 PUIs, and 460 control patients). COVID+ patients were more likely to have minority ethnicity (Hispanic 23%, Black 24%) and had a higher prevalence of diabetes mellitus (46%) (all p < 0.001 relative to PUIs). COVID+ patients were more likely to present with cardiogenic shock (18%) but were less likely to receive invasive angiography (78%) (all p < 0.001 relative to control patients). Among COVID+ patients who received angiography, 71% received PPCI and 20% received medical therapy (both p < 0.001 relative to control patients). The primary outcome occurred in 36% of COVID+ patients, 13% of PUIs, and 5% of control patients (p < 0.001 relative to control patients). CONCLUSIONS: COVID+ patients with STEMI represent a high-risk group of patients with unique demographic and clinical characteristics. PPCI is feasible and remains the predominant reperfusion strategy, supporting current recommendations.

Trends, Management, and Outcomes of Acute Myocardial Infarction Hospitalizations With In-Hospital-Onset Versus Out-of-Hospital Onset: The ARIC Study.

Background Acute myocardial infarction (AMI) with in-hospital onset (AMI-IHO) has poor prognosis but is clinically underappreciated. Whether its occurrence has changed over time is uncertain. Methods and Results Since 1987, the ARIC (Atherosclerosis Risk in Communities) study has conducted adjudicated surveillance of AMI hospitalizations in 4 US communities. Our analysis was limited to patients aged 35 to 74 years with symptomatic AMI. Patients with symptoms initiating after hospital arrival were considered AMI-IHO. A total of 26 678 weighted hospitalizations (14 276 unweighted hospitalizations) for symptomatic AMI were identified from 1995 to 2014, with 1137 (4%) classified as in-hospital onset. The population incidence rate of AMI-IHO increased in the 4 ARIC communities from 1995 through 2004 to 2005 through 2014 (12.7-16.9 events per 100 000 people; P for 20-year trend <0.0001), as did the proportion of AMI hospitalizations with in-hospital onset (3.7%-6.1%; P for 20-year trend =0.03). The 10-year proportions were stable for patients aged 35 to 64 years (3.0%-3.4%; P for 20-year trend =0.3) but increased for patients aged ≥65 years (4.6%-7.8%; P for 20-year trend =0.008; P for interaction by age group =0.04). AMI-IHO had a more severe clinical course with lower use of AMI therapies or invasive strategies and higher in-hospital (7% versus 3%), 28-day (19% versus 5%), and 1-year (29% versus 12%) mortality (P<0.0001 for all). Conclusions In this population-based community surveillance, AMI-IHO increased from 2005 to 2014, particularly among older patients. Quality initiatives to improve recognition and management of AMI-IHO should be especially focused on hospitalized patients aged >65.

Mortality differences among patients with in-hospital ST-elevation myocardial infarction.

BACKGROUND: In-hospital ST-elevation myocardial infarction (STEMI) is associated with a higher mortality rate than out-of-hospital STEMI. Quality measures and universal protocols for treatment of in-hospital STEMI do not exist, likely contributing to delays in recognition and treatment. HYPOTHESIS: To analyze differences in mortality among three subsets of patients who develop in-hospital STEMI. METHODS: This was a multicenter, retrospective observational study of patients who developed in-hospital STEMI at six United States medical centers between 2008 and 2017. Patients were stratified into three groups: (1) cardiac, (2) periprocedure, or (3) noncardiac/nonpostprocedure. Outcomes examined include time from electrocardiogram (ECG) acquisition to cardiac catheterization lab arrival (ECG-to-CCL) and survival to discharge. RESULTS: We identified 184 patients with in-hospital STEMI (mean age 68.7 years, 58.7% male). Group 1 (cardiac) patients had a shorter average ECG-to-CCL time (69 minutes) than group 2 (periprocedure, 215 minutes) and group 3 (noncardiac/nonpostprocedure, 199 minutes). Compared to group 1, survival to discharge was lower for group 2 (OR 0.33, P = .102) and group 3 (OR 0.20, P = .016). After adjusting for prespecified covariates, the relationship between group and survival showed a similar trend but did not reach statistical significance. CONCLUSIONS: Patients who develop in-hospital STEMI in the context of a preceding procedure or noncardiac illness appear to have longer reperfusion times and higher in-hospital mortality than patients admitted with cardiac diagnoses. Larger studies are warranted to further investigate these observations. Health systems should place an increased emphasis on developing quality metrics and implementing quality improvement initiatives to improve outcomes for in-hospital STEMI.

Intra-procedural arrhythmia during cardiac catheterization: A systematic review of literature.

BACKGROUND: Cardiac catheterization is among the most performed medical procedures in the modern era. There were sporadic reports indicating that cardiac arrhythmias are common during cardiac catheterization, and there are risks of developing serious and potentially life-threatening arrhythmias, such as sustained ventricular tachycardia (VT), ventricular fibrillation (VF) and high-grade conduction disturbances such as complete heart block (CHB), requiring immediate interventions. However, there is lack of systematic overview of these conditions. AIM: To systematically review existing literature and gain better understanding of the incidence of cardiac arrhythmias during cardiac catheterization, and their impact on outcomes, as well as potential approaches to minimize this risk. METHODS: We applied a combination of terms potentially used in reports describing various cardiac arrhythmias during common cardiac catheterization procedures to systematically search PubMed, EMBASE and Cochrane databases, as well as references of full-length articles. RESULTS: During right heart catheterization (RHC), the incidence of atrial arrhythmias (premature atrial complexes, atrial fibrillation and flutter) was low (< 1%); these arrhythmias were usually transient and self-limited. RHC associated with the development of a new RBBB at a rate of 0.1%-0.3% in individuals with normal conduction system but up to 6.3% in individuals with pre-existing left bundle branch block. These patients may require temporary pacing due to transient CHB. Isolated premature ventricular complexes or non-sustained VT are common during RHC (up to 20% of cases). Sustained ventricular arrhythmias (VT and/or VF) requiring either withdrawal of catheter or cardioversion occurred infrequently (1%-1.3%). During left heart catheterizations (LHC), the incidence of ventricular arrhythmias has declined significantly over the last few decades, from 1.1% historically to 0.1% currently. The overall reported rate of VT/VF in diagnostic LHC and coronary angiography is 0.8%. The risk of VT/VF was higher during percutaneous coronary interventions for stable coronary artery disease (1.1%) and even higher for patients with acute myocardial infarctions (4.1%-4.3%). Intravenous adenosine and papaverine bolus for fractional flow reserve measurement, as well as intracoronary imaging using optical coherence tomography have been reported to induce VF. Although uncommon, LHC and coronary angiography were also reported to induce conduction disturbances including CHB. CONCLUSION: Cardiac arrhythmias are common and potentially serious complications of cardiac catheterization procedures, and it demands constant vigilance and readiness to intervene during procedures.

Plaque herniation after stenting the culprit lesion with myocardial bridging in ST elevation myocardial infarction: A case report.

BACKGROUND: Myocardial bridging (MB) is increasingly recognized to stimulate atherogenesis, which may contribute to an acute coronary syndrome. Stenting the coronary segment with MB has been recognized to have an increased risk of in-stent restenosis, stent fracture and coronary perforation. The safety and efficacy of stenting the culprit lesion with overlaying MB in ST elevation myocardial infarction (STEMI) as primary reperfusion therapy has not been established. CASE SUMMARY: We reported a patient who presented with inferior STEMI with a culprit lesion of an acute thrombotic occlusion in the right coronary artery and thrombolysis and thrombin inhibition in myocardial infarction 0 flow. After the stent placement during primary percutaneous coronary intervention, intravascular ultrasound revealed MB overlying the stented segment where heavy atherosclerotic plaque were present. Likely due to the combination of plaque herniation or prolapse caused by MB, as well as local increased inflammation and thrombogenicity, acute stent thrombosis occurred at this region, which led to acute stent failure. The patient required an emergent repeated cardiac catheterization and placing a second layer of stent to enhance the radial strength and reduce the inter-strut space. CONCLUSION: Plaque herniation or prolapse after stenting a MB segment in STEMI is a potential etiology for acute stent failure.

Elevated left ventricular end diastolic pressure is associated with increased risk of contrast-induced acute kidney injury in patients undergoing percutaneous coronary intervention.

AIMS: To study the correlation between intra-procedural left ventricular end-diastolic pressure (LVEDP) and the development of contrast-induced acute kidney injury (CI-AKI) in patients undergoing percutaneous coronary intervention (PCI). METHODS AND RESULTS: A single center retrospective observational study compared clinical and hemodynamic characteristics of patients who developed post-PCI CI-AKI with those did not. CI-AKI was defined as an absolute increase in serum creatinine ≥0.5 mg/dl or an increase ≥25% from baseline 48-72 h after the administration of contrast medium. Among 1301 consecutive patients who underwent PCI, 125 patients (9.6%) developed CI-AKI. The CI-AKI group had a higher average LVEDP (18.4 ± 8.7 vs 14.4 ± 6.6 mm Hg; p < .0001) and higher prevalence of elevated LVEDP (≥20 mm Hg) than those without CI-AKI (47.2% vs 23.3%, p < .0001). After adjustments, elevated LVEDP remained independently associated with CI-AKI (OR 2.21; 95% CI 1.40-3.50). LVEDP predicted the development of CI-AKI with a receiver operating characteristic area under curve (AUC) of 0.64. The association between elevated LVEDP and the risk of CI-AKI was stronger in patients with reduced ejection fraction (EF ≤ 40%) (OR = 4.08; 95% CI: 1.68-9.91) than those with preserved EF (OR = 1.69; 95% CI: 0.94-3.04) (p value for interaction = .0003). Patients who had LVEDP ≥ 20 mm Hg and LVEF ≤ 40% had a post-PCI incidence rate of developing CI-AKI of 36.5%. CONCLUSIONS: Elevated intra-procedural LVEDP (≥20 mm Hg) is independently associated with increased risk of CI-AKI for patients undergoing cardiac catheterization and PCI, especially in the setting of reduced LVEF (≤40%).

A Systematic Approach to Evaluate Patients Presenting With ST-Segment Elevation in Lead aVR: A Case Series.

ST-segment elevation (STE) in the lead aVR indicates global ischemia of the myocardium and is often associated with obstructive coronary artery disease (CAD). We report a serial of cases presenting with STE in aVR and diffuse ST depressions in more than six other leads as a common feature, but of different etiologies, i.e., severe anemia due to gastrointestinal bleeding; drug over-dose-induced vasospasm and tachycardia, and severe CAD involving distal left main and ostial right coronary arteries, which required specific management approaches. We categorize the possible causes of STE in aVR with or without diffuse ST depression ECG according to whether anticoagulation/antithrombotic agents are indicated, contra-indicated, and propose a systematic approach in evaluating and managing these patients.

Mechanisms of ST Elevation Myocardial Infarction in Patients Hospitalized for Noncardiac Conditions.

ST elevation myocardial infarction (STEMI) occurring in patients hospitalized for a noncardiac condition is associated with a high mortality rate and thus we sought to determine the mechanisms underlying STEMI in this patient population. This is a single center retrospective study of 70 patients who had STEMI while hospitalized on a noncardiac service and underwent coronary angiography. Thrombotic in-hospital STEMI was defined by angiographic or intravascular imaging evidence of intracoronary thrombus, plaque rupture, or stent thrombosis. Thirty-six (51%) inpatient STEMIs developed in the operating room or various postoperative stages and 6 (9%) after endoscopy or a percutaneous procedure. Thrombotic etiologies were found in 39 (56%) patients. Nonthrombotic etiologies included vasospasm, supply-demand mismatch, and takotsubo cardiomyopathy. Patients in the thrombotic group were more likely to have antiplatelet medications discontinued on admission, had higher peak troponin levels and were more likely to undergo percutaneous coronary intervention than patients in the nonthrombotic group. Exposure to vasopressors, time from ECG to angiography, post-STEMI ejection fraction, length of stay, and in-hospital mortality were similar in both groups. There was no difference in the use of percutaneous coronary intervention in patients but longer ECG to coronary angiography times and fivefold higher in-hospital mortality in thrombotic inpatient STEMI compared with 643 patients who presented with an out-of-hospital STEMI during the same time period. In conclusion, thrombotic and nonthrombotic mechanisms cause STEMI in hospitalized patients and are associated with a high mortality.

MicroRNA-21 mediates high phosphate-induced endothelial cell apoptosis.

Hyperphosphatemia, the elevated level of inorganic phosphate (Pi) in serum, is associated with increased cardiovascular morbidities and mortality. The effects of high Pi on endothelial cells are not well studied. This study investigated high Pi-induced endothelial cell apoptosis and the role of microRNA-21. Mouse myocardial endothelial cells (MEC) were cultured in normal (1 mM) and high (5 mM) Pi conditions. Apoptosis was detected by TUNEL staining and flow cytometry. MicroRNA profiles of MEC response to changes in Pi concentration were obtained using gene expression arrays. Expression levels of the microRNA-21 target genes, programmed cell death gene 4 ( PDCD4), poly(ADP-ribose) polymerase ( PARP), and phosphatase and tensin homolog ( PTEN), as well as NF-κB were measured by Western blotting and RT-PCR. MicroRNA-21-specific inhibitors and mimics were used to study effects of microRNA-21 on MEC apoptosis and gene expression regulations. High Pi induced MEC apoptosis and upregulated microRNA-21 expression. MicroRNA-21-specific mimics reproduced high Pi-induced apoptosis in normal Pi medium, and microRNA-21 inhibitors ameliorated the high Pi induction of apoptosis, suggesting that microRNA-21 mediated high Pi-induced MEC apoptosis. The microRNA-21 targets PDCD4, PTEN, PARP, and NF-κB were significantly downregulated in high Pi conditions. High Pi-induced downregulation of PDCD4 was abolished by microRNA-21 inhibitors and selective ERK inhibitor (selumetinib) and was reproduced by microRNA-21 mimics. Inhibitors and mimics of microRNA-21 did not have effects on high Pi-induced NF-κB downregulation. Selumetinib blocked high Pi-induced NF-κB downregulation. MicroRNA-21 mediates high Pi-induced endothelial cell apoptosis, which involves an ERK1/2/microRNA-21/PDCD4 pathway. High Pi-induced downregulation of NF-κB expression is mediated by an ERK1/2 signaling-dependent but microRNA-21-independent mechanism.

Correlation of infarct size with invasive hemodynamics in patients with ST-elevation myocardial infarction.

OBJECTIVES: To identify invasive hemodynamic parameters that correlate with infarction size in patients with ST-elevation myocardial infarction (STEMI). BACKGROUND: Invasive hemodynamics obtained during primary percutaneous coronary intervention (PPCI) are predictive of mortality in STEMI, but which parameters correlate best with the size of the infarction are unknown. METHODS: This is a single-center study of 405 adult patients with STEMI who had left ventricular end-diastolic pressure (LVEDP) measured during PPCI. Size of infarction was estimated by peak troponin I level and ejection fraction (LVEF) determined by echocardiography. RESULTS: The average (±SD) age was 61 ± 14 years, TIMI STEMI risk score was 3.5 ± 2.7 and Grace score was 157 ± 42. Hemodynamic parameters that correlated best with EF were LVEDP (r = -0.40), PP (r = 0.24), and SBP/LVEDP ratio (r = 0.22) and with peak troponin were SBP/LVEDP ratio (r = -0.41), LVEDP (r = 0.31), and PP (r = -0.29). SBP/LVEDP (AUC = 0.76) and SBP (AUC = 0.77) had a stronger association with in-hospital mortality than did LVEDP (AUC = 0.66) or PP (AUC = 0.64). Door-to-balloon time did not affect the correlations between hemodynamic parameters and infarct size. CONCLUSIONS: In this sample of 405 patients undergoing PPCI, SBP/LVEDP ratio had the strongest correlation with peak troponin levels and LVEDP with EF, whereas SBP/LVEDP and SBP had a strong association with in-hospital mortality. These results suggest that measurement of LVEDP as well as SBP may help risk stratify patients during PPCI.