bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 20665: Cardiac Arterial Spin Labeling MRI as a Novel Approach for in vivo Quantification of the Area-At-Risk
Authors: Dongworth Rachel , Campbell-Washburn Adrienne E , Roberts Thomas , Yellon Derek M , Lythgoe Mark , Hausenloy Derek J
Published: July 2021

Introduction:
T2-weighted cardiac magnetic resonance (CMR) imaging, which detects myocardial edema, has been used to retrospectively delineate the area-at-risk (AAR) in clinical cardioprotection studies. However, some of these cardioprotective interventions have been reported to reduce the extent of myocardial edema, thereby affecting the AAR delineated by T2-CMR. Here, we investigate arterial spin labelling (ASL)-CMR, which measures myocardial perfusion, as an alternative approach to measuring the AAR following acute ischemia-reperfusion injury (IRI).

Methods:
B6sv129 mice (10-14 weeks old) were subjected to an in vivo left main coronary artery ligation for 30 minutes followed by 72 hours reperfusion following which CMR was performed to determine MI size (late gadolinium enhancement) and the AAR (T2-mapping CMR and ASL CMR). These were then validated against MI size and the AAR measured by ‘gold-standard’ triphenyl tetrazolium chloride and Evan’s blue staining, respectively. Animals were subjected to a standard ischemic preconditioning (IPC) protocol comprising 5 minutes ischemia and reperfusion prior to the index ischemic insult.

Results:
T2-maps showed clearly defined regions of elevated T2-signal corresponding to the AAR delineated by histology (AAR/LV% in control: T2-CMR 60.4±2.4 versus histology 64.3±2.5:N=6/group;P>0.05). However, in IPC-treated animals, the T2-maps significantly underestimated the AAR (AAR/LV% with IPC: T2-CMR 46.0±13.2 versus histology 59.8±7.8:N=10/group;P<0.05). ASL-CMR also revealed clearly defined regions of attenuated ASL signal (indicated reduced myocardial blood flow) which appeared to correspond to the AAR delineated by histology (AAR/LV% in control: ASL-CMR 60.6±4.3 versus histology 64.3±3.9:N=6/group;P>0.05). Crucially, the estimation of the AAR by ASL-CMR was not affected by IPC (AAR/LV% with IPC: ASL-CMR 53.4±7.9 versus histology 58.0±3.0:N=8/group;P>0.05).

Conclusions:
We find that ASL-CMR has the potential to retrospectively delineate the AAR in the adult murine heart subjected to acute IRI in a similar manner to T2-mapping CMR. Crucially, unlike T2-mapping CMR however, the AAR delineated by ASL-CMR was not affected by the cardioprotective intervention, IPC.
Abstract 20670: Coronary Microembolization During Transfemoral Transcatheter Aortic Valve Implantation: An Intracoronary Doppler Study
Authors: Al-Rashid Fadi , Hildebrandt Heike , Baars Theodor , Neumann Till , Nensa Felix , Nassenstein Kai , Wendt Daniel , Thielmann Matthias , Jakob Heinz , Kottenberg Eva , Perters Jürgen , Erbel Raimund , Heusch Gerd , Kahlert Philipp
Published: July 2021

Background:
A postprocedural increase of the serum troponin I concentration (TnI) reflects myocardial injury and occurs frequently during transcatheter aortic valve implantation (TAVI). Periprocedural coronary microembolization is a potential cause of such injury. We therefore evaluated each step of the transfemoral TAVI procedure for coronary embolization using intracoronary Doppler (ICD) in the left anterior descending (LAD) artery.

Methods:
15 high-risk patients with severe, symptomatic aortic valve stenosis (age 79 ± 45 yrs; EuroScore 17 ± 4%) who underwent transfemoral TAVI using the balloon-expandable Edwards bioprosthesis were included. ICD examinations were recorded and evaluated off-line for high-intensity transient signals (HITS). Perioperative concentrations of TnI were serially measured within the first 72 h after TAVI, and a cardiac MRI with late gadolinium-enhancement (LGE) was performed within 7 days.

Results:
HITS were detected in all patients (figure 1), mostly during the initial crossing of the native valve and positioning of the prosthesis with subsequent implantation. TnI peaked at 24 h after TAVI (3.17 ng/ml), and LGE was observed in only one single case. There was no correlation between amount of HITS and TnI area under the curve in the first 72 h after TAVI.

Conclusions:
Procedural HITS were detected by ICD in all patients undergoing transfemoral TAVI. The highest amount of HITS was observed during initial valve passage and positioning of the prosthesis with subsequent implantation. However, no association was found between the number of HITS and myocardial injury, as reflected by increased serum TnI concentrations or LGE on cardiac MRI.
Abstract 20675: Longest Available Follow-Up of Drug-Eluting Stents in Real World Practice - Outcomes up to 12 Years From the DESIRE Registry
Authors: Costa Ricardo A , Sousa Amanda , Moreira Adriana , Moreira Adriana , Costa J. Ribamar , Maldonado Galo , Cano Manuel , Gordilho Carlos , Damiani Lucas P , Campos Cantidio , Pavanello Ricardo , Sousa J. Eduardo
Published: July 2021

Background:
Despite the marked efficacy demonstrated by drug-eluting stents (DES) in reducing neointimal proliferation, and therefore, the need for target lesion revascularization (TLR), persistent concerns regarding long-term safety and efficacy, especially in more complex subset, are still.

Methods:
The DESIRE Registry is a large, prospective, non-randomized, single center study assessing the late outcomes of unselected pts treated with DES. Overall, 5,541 pts were consecutively enrolled from May/02-Jun/14. Clinical follow-up (FU) (97%) was performed yearly up to 12 yrs (median 4.9 yrs). Stent thrombosis (ST) was defined according to the ARC.

Results:
Mean age was 65 yrs, 31% had diabetes, 29% current smokers, 42% presented with ACS (17% recent myocardial infarction, MI), and the majority of lesions were highly complex (67% type B2/C). Overall, there were 8,919 lesions treated with 9,537 DES, and angiographic success was 99%. During the FU period, cumulative event rates were major adverse cardiac events (cardiac death, myocardial infarction, or TLR) 32%, myocardial infarction 8%, TLR 21%, and cardiac death 6%. As for stent thrombosis, overal rate was 2.4%, given that 95% of patients were free from this event up to 12 years. In the multivariate model, independent predictors of major adverse cardiac events were: prior revascularization by percutaneous intervention (HR 1.21, p=0.03) or surgery (HR 1.53, p<0.001), dyslipidemia (HR 1.20, p=0.03), renal insufficiency (HR 1.41, p<0.001), peripheral vascular disease (HR 2.06, p<0.001), long lesions (HR 1.38, p<0.001), acute coronary syndrome (HR 1.39, p<0.001), and residual stenosis (HR 1.02, p<0.001). As for stent thrombosis, predictors were: recent myocardial infarction (HR 2.66, p=0.001), multiple stents implanted (HR 1.89, p=0.002), saphenous vein graft (HR 2.21, p=0.004), and residual stenosis (HR 1.03, p=0.03).

Conclusions:
At very long-term follow-up (up to 12 years) in a large cohort of patients from the real world practice, cumulative event rates included TLR in 21% and stent thrombosis in 2.4%. Overall, there were no safety concers, given that 95% of patients were free from stent thrombosis up to 12 years.
Abstract 20699: GMP-Grade Cardiomyocyte Differentiation Media System for Pluripotent Stem Cells in Basic and Translational Research
Authors: Boucher Shayne , Jones Stacy , Kuninger David , Vemuri Mohan
Published: July 2021

Objective:
Current protocols for differentiating pluripotent stem cells (PSCs) have led to heterogeneous results, varying purity levels, and long lead times for generation of cardiomyocytes. We hypothesized that a simplified and rapid cardiomyocyte differentiation media system can be developed in a scalable workflow to enable generation of large numbers of consistent, spontaneously active cardiomyocytes that could be used in basic and translational research.

Methods:
High quality PSCs were maintained under xenofree, feeder-free culture conditions. At time of passaging, PSC were dissociated with 0.5 mM EDTA, seeded on 1:100 Geltrex
©
-coated surface as small clusters at ~0.5 to 1 x 10
5
/well of a 12-well plate and maintained for four days under serum-free condition. After reaching target confluence of ~60 to 80%, an induction media was added for two days followed by addition of a second induction media for two days. After the induction step, the media was replaced with maintenance media and re-fed every other day for up to five weeks. PSC-derived cardiomyocytes were analyzed by morphology, gene expression, flow cytometry, immunocytochemistry and multi-electrode array (MEA).

Results:
We observed individual beating cells by Day 7 and contracting syncytia by Day 10. An over 100 fold increase in cell number was noted from the time of plating to generation of contracting syncytia of cardiomyocytes. Quantitative flow cytometry detected populations of troponin T type 2 (TNNT2)-immunoreactive cells that reached as high as 96.6%. Number of TNNT2-positive cells dropped by 20% when induced at 90% versus 60% confluency. PCR studies confirmed expression of mesoderm (T, MIXL1, MESP1), cardiac mesoderm (ISL1, GATA4, MEF2C) and mature cardiomyocyte genes (NKX2.5, TNNT2, MYH6). Immunocytochemistry studies verified expression of cardiac markers NKX2.5,GATA4, MEF2C, TNNT2 and MYH6. Initial MEA studies corroborated the presence of electrically active cells.

Conclusions:
We conclude that a simplified complete differentiation media system could serve as a standardized culture system for generating large numbers of consistent, spontaneously active cardiomyocytes for basic and translational research studies.
Abstract 212: Advantage of CPR-First Over Call-First Basic Life Support Actions in Out-of-Hospital Cardiac Arrest of Noncardiac Etiology and Young Adults/Children
Authors: Iwasaki Hose , Kamikura Takahisa , Maeda Testuo , Kubo Minoru , Takei Yutaka , Hashimoto Masaaki , Inaba Hideo
Published: July 2021

Aim:
To assess the benefit of immediate call-first or CPR-first basic life support (BLS) in promoting a better outcome of out-of-hospital cardiac arrest (OHCA).

Methods:
From the nation-wide database of 2005 to 2012, we extracted bystander-witnessed OHCAs in which both emergency call and CPR were performed by bystanders on their own initiative (without instruction over telephone) within 6 min of witnessing patient collapse. These cases were categorized into the following four groups; immediate Call+CPR group (N=10,195 ,emergency call and/or CPR within 2 min of witness, call-CPR time interval = 0 or 1 min), immediate Call-First group (N=1,820 , emergency call within 2 min of witness, call-CPR interval = 2[[Unable to Display Character: ‒]]4 min), immediate CPR-First group (N=5,446 , bystander CPR within 2 min of witness, CPR-call interval =2[[Unable to Display Character: ‒]]4 min), the delayed Call/CPR group (N=4,671, the remaining cases). We compared the rates of neurologically favorable survival at 1-month among the four groups for all OHCAs and subgroups of OHCAs.

Results:
The overall survival rate was highest in Call-First group and lowest in delayed Call/CPR group (Figure). The rate of Call-First group was significantly higher than that of CPR-First group in OHCAs of presumed cardiac etiology (17.2% vs. 14.1%, unadjusted OR; 95% CI, 1.26; 1.05[[Unable to Display Character: ‒]]1.52). The rate of CPR-First group was significantly higher than that of Call-First group in OHCAs of presumed non-cardiac etiology (7.7% vs. 5.0%, 1.59; 1.11[[Unable to Display Character: ‒]]2.33) and young adults/children (age<35y, 32.8% vs. 17.8%, 2.25; 1.33[[Unable to Display Character: ‒]]3.95). Multiple logistic regression analysis confirmed the results of univariate analyses and disclosed that delayed Call/CPR is associated with poor outcomes.

Conclusions:
The immediate (within 2 min) CPR-first BLS action followed by emergency call without a large (>4 min) delay may be recommended when a single bystander having a fundamental skill to initiate CPR witnesses OHCAs of non-cardiac etiology and young adults/children.
Abstract 216: A Sensitivity Analysis of Incremental Cost-Effectiveness Ratio of the Nationwide Public Access Defibrillation Program in Japan
Authors: Kaneko Hiroshi , Hatanaka Tetsuo , Nagase Aki , Marukawa Seishiro , Sakamoto Tetsuya
Published: July 2021

Introduction:
We have previously estimated the cost of and quality-adjusted life year (QALY) gained with ~200,000 AEDs placed in Japan between 2004 through 2009, and reported that the maximum likelihood estimate (MLE) of the incremental cost-effectiveness ratio (ICER) to be ~$93,980/QALY. To evaluate the robustness of the estimated ICER, we conducted a sensitivity analysis using Monte Carlo simulation.

Methods:
Over the study period, 3,927 patients received public access defibrillation (PAD). A control group was created by extracting, from the national database, another group of 3,927 cardiac arrest patients who did not receive PADs but otherwise matched with regard to confounders including age, sex, response time and others. The difference of the total QALY in the 2 groups yielded incremental effectiveness gained by the PAD program. The sum of the total cost for AED purchase and maintenance, cost of BLS training for first responders, and differential cost for medical care yielded the incremental cost. The value for each variable needed to calculate the incremental cost and effectiveness was randomly varied in such a way that followed the pre-defined probability density function (Table). Monte Carlo simulation was repeated 10,000 times to estimate the MLE and its 95% CI for ICER.

Results:
The MLE (95% CI) for the incremental cost and incremental effectiveness was ~$ 580 million (577- 583 million) and ~7,559 (6,298- 8,858) QALY, yielding ICER of $77,320 ($65,503- 92,017) /QALY (figure).

Conclusions:
Our estimate of the ICER seemed to be relatively robust to several assumptions. The ICER of the whole Japan PAD program seemed to be higher than desirable but still acceptable.
Abstract 222: Optimizing the Application of a Mechanical Chest Compression Device Within a High-Performance CPR Approach to Out-of-Hospital Cardiac Arrest Resuscitation
Authors: Levy Michael , Yost Dana , Walker Robert G , Scheunemann Erich A , Mendive Steve R
Published: July 2021

Background:
Minimizing the chest compression pause associated with application of a mechanical CPR (mCPR) device is a key component of optimal integration of mCPR into the overall resuscitation process. As part of a multi-agency implementation project, Anchorage Fire Department deployed LUCAS mCPR devices on BLS and ALS vehicles for initiation early in resuscitation efforts. A 2012 report from that project identified the pause interval for mCPR device application as a key opportunity for quality improvement (QI). In early 2013 we began a QI initiative to reduce device application time and optimize the overall CPR process, which included education on the importance of minimizing pauses, training on techniques for efficient device application, and a requirement for two manual CPR cycles prior to initiation of mCPR. To assess QI initiative effectiveness, we compared key CPR process metrics from before to during and after its implementation.

Methods:
We included all cases of EMS-treated out-of-hospital cardiac arrest during 2012 and 2013 in which mCPR was used and the defibrillator electronic record was available. Continuous ECG and impedance data were analyzed to measure chest compression fraction, duration of the pause from last manual to first mechanical compression, and duration of the longest overall pause in the resuscitation effort.

Results:
Compared to cases from 2012 (n=61), median (25th, 75th percentile) duration of the pause prior to first mCPR compression for cases from 2013 (n=71) decreased from 21 (15, 31) to 7 (4, 12) seconds (p<0.001), while median chest compression fraction increased from 0.90 (0.88, 0.93) to 0.95 (0.93, 0.96) (p<0.001). Median duration of the longest pause decreased from 25 (20, 35) to 13 (10, 20) seconds (p<0.001), while the proportion of cases where the longest pause was for mCPR device application decreased from 74% to 32% (p<0.001).

Conclusions:
Our QI initiative substantially reduced the duration of the pause prior to first mCPR compression. Combined with the simultaneous significant increase in compression fraction and significant decrease in duration of the longest pause, this finding strongly suggests a large improvement in mCPR device application efficiency within an overall high-performance CPR process.
Abstract 228: Deconstructing the Cerebral Performance Category: Introducing the CPC-E
Authors: Raina Ketki D , Balouris Sondra , Rittenberger Jon C , Callaway Clifton W , Rogers Joan C , Holm Margo B
Published: July 2021

Objective:
The Cerebral Performance Category (CPC) is considered the “gold” standard outcome tool to quantify and categorize post-CA outcomes, but lacks psychometric validation. The study objective was to create a new instrument with content validity, inter-rater reliability, and clinical utility called the CPC-Extended (CPC-E).

Methods:
Potential domains were identified through content analyses of the CPC and literature review. A panel comprised of CA and rehabilitation experts reviewed the CPC-E in iterative rounds. Following each round the CPC-E was revised resulting in near 100% consensus among experts. Inter-rater reliability and clinical feasibility of the CPC-E were tested by administering the CPC-E to CA survivors prior to discharge from the hospital. Intraclass correlation coefficients and descriptive statistics were used to examine inter-rater reliability and descriptive statistics respectively.

Results:
The CPC-E has 10 independent domains: Alert, Logical Thinking, Attention, Short-Term Memory, Motor, Basic Activities of Daily Living, Mood, Fatigue, Complex Activities of Daily Living, and Return to Work. Each domain has 5 levels with 1 being the best response for the domain and 5 being the worst. Inter-rater reliability for the domains is excellent (n = 20, range = 0.88 - 1.0). The CPC-E took a mean (SD) of 6.03 (3.68) minutes to administer and score. No missing data were reported and clinicians reported that it was easy to administer and use.

Conclusion:
The CPC-E offers an efficient, comprehensive tool with good psychometric properties to measure outcomes after CA. Clinically, the multi-domain CPC-E yields a profile of outcomes at the time of discharge that could “signal” a referral to rehabilitation or to a support service associated with a particular domain. Future studies will examine other psychometric properties of the CPC-E, including responsiveness to change.
Abstract 235: Emergent PCI Is Associated with Good Neurological Outcome After OHCA
Authors: Ryoo Hyun Wook , Chikani Vatsal , Mullins Margaret , Vadeboncoeur Tyler , Irisawa Taro , Spaite Daniel , Bobrow Bentley
Published: July 2021

Background:
Previous observational studies have demonstrated that outcomes after OHCA can be significantly improved with therapies such as mild therapeutic hypothermia and percutaneous coronary intervention (PCI). However, the optimal candidate and timing for PCI in OHCA remains unknown. This study aimed to assess the impact of emergent PCI on survival and neurological outcome after OHCA.

Methods:
This is a prospective observational study from a statewide OHCA database in Arizona. Patients included were greater than 18 years old who received CPR and were admitted to one of 34 recognized cardiac receiving centers. Patients who did not achieve ROSC, died within 2 hours of hospital arrival, and DNAR patients were excluded since the likelihood of PCI impacting outcome in these patients is questionable. An in-hospital post-arrest database, including PCI (Y/N), was linked with an Utstein-style OHCA database. Univariate and multivariate logistic regression were utilized to assess the association between PCI and survival to hospital discharge and neurological outcome.

Results:
During this study period (1-1-2011-12-31-2013), there were a total of 6,543 adult OHCA patients. After exclusions, 782 patients with suspected cardiac etiology OHCA were analyzed. The median age of patients was 64.0 years (Q1:54.0, Q3:73.0) and 70.2% were male. Among them 458 (58.6%) and 238 (30.4%) patients underwent the emergency coronary angiogram (CAG), and Primary PCI, respectively. Among PCI patients, the rate of survival to hospital discharge was 75.2%, vs. 60.4% for those without PCI (p<0.001) and good cerebral outcome (CPC 1-2) was found in 67.6%, vs. 44.3% of those without PCI (p<0.001). After adjusting for age, gender, initial rhythm, bystander CPR, and hypothermia, the Odds Ratio was 1.2 (95% CI:0.8-1.8) for survival and 2.8 (95% CI:1.5-5.1) for good neurologic outcome (CPC 1-2) among PCI patients.

Conclusion:
This study shows an association with emergent PCI and good neurologic outcome after OHCA. Further study is necessary to determine a potential causal relationship between PCI and outcome.
Abstract 268: Quantitative Performance Assessment of Simulated Pediatric Cardiopulmonary Resuscitation
Authors: Donoghue Aaron , Tofil Nancy , Brown Linda , Overly Frank , Cheng Adam
Published: July 2021

Background:
Methods to quantitatively measure performance during resuscitative care are lacking in published literature. Members of our group have previously published psychometric analyses of task-based scoring instruments used in educational research in pediatric resuscitation. These published investigations used instruments that were designed for specific cases in pediatric resuscitation, rather than for a more generalizable application. We hypothesize that a novel scoring instrument will reliably assess clinical performance during simulated cardiac arrest.

Methods:
This study was conducted at 11 pediatric centers in Canada and the US. Teams of pediatric providers performed a simulated cardiac arrest scenario (asystole for 6 minutes, VF for 6 minutes). A task-based scoring instrument was designed by investigator consensus using a 0, 1, or 2 point scoring system to rate performance during cardiac arrest. The items were chosen according to the essential steps in the pulseless arrest algorithm of the AHA Pediatric Advanced Life Support course and include CPR performance parameters (chest compression rate, depth, release, pauses), defibrillation (dose in J/kg, timing), and epinephrine (dose, timing). Multiple raters reviewed and scored a set of simulations. Overall interrater reliability was measured; a fully-crossed generalizability study with team and rater as facets was performed to determine the variance in scores ascribable to each facet; a decision study was done to determine the effect of additional raters and scenarios on the G coefficient.

Results:
Three raters scored four videos. Overall scores ranged from 53/90 (59%) to 73/90 (81%) possible points. Intraclass correlation coefficient was 0.77 (F 3,8 = 4.46, p = 0.04). Variance components were 21% for rater, 57% for scenario. G coefficient was 0.80; by D study this increased to 0.91 and 0.93 with 8 and 10 raters, respectively.

Conclusions:
A novel scoring instrument for quantifying performance during pediatric cardiac arrest showed modest reliability and generalizability. Future studies should examine the effect of a larger number of raters and/or scenarios on generalizability, as well as the utility of the instrument in assessing real clinical performance.
Abstract 275: Automated External Defibrillator with Real-Time Audiovisual Feedback System Improves the Quality of Cardiopulmonary Resuscitation
Authors: Hayashi Kenji , Ushikoshi Hiroaki , Matsumaru Naoki , Nachi Sho , Nachi Hikaru , Morishita Kentaro , Sugihara Hiroko , Fukao Ayumi , Toyoda Izumi , Ogura Shinji
Published: July 2021

Background:
Public access defibrillation (PAD) with automated external defibrillator (AED) is a widely available and beneficial intervention for cardiac arrest. The quality of chest compressions (CC) is an important determinant of the outcome of cardiopulmonary resuscitation (CPR). In Japan, AED with real-time audiovisual feedback is being implemented, and has been available to bystanders since 2011. However, the benefit of CC feedback systems for laypersons remains unclear. In this study, we sought to determine the effects of audiovisual feedback system on the quality of CC in bystanders with different medical backgrounds.

Methods:
A total of 478 individuals (151 healthcare professionals [mean age, 31.3 years], 76 medical students [mean age, 23.6 years], and 251 non-healthcare professionals [mean age, 40.1 years]) participated in a CPR quality improvement challenge. Participants performed two 2-min trials of CC on a training manikin equipped with an accelerometer-based system for measuring both rate and depth of CC. Real-time audiovisual feedback was disabled during first trial, but activated during the second trial. The quality of CC was evaluated by counting the number of compressions with the appropriate depth (5.0-10 cm) and rate (100-120 cpm) in each trial.

Results:
Among all participants, mean depth of CC was higher (6.35 vs. 5.87 cm), and mean rate was lower (102.4 vs. 112.2 cpm) when the feedback system was activated than when it was disabled (p < 0.05). When real-time feedback was activated, non-healthcare professional participants performed CC of greater depth (6.41 vs. 5.63 cm) than healthcare professionals (6.25 vs. 6.09 cm) and medical students (6.34 vs. 6.19 cm) (p < 0.05). The quality index of CC, which the percentage of adequate depth and rate, was also significantly improved regardless medical backgrounds (p < 0.05).

Conclusions:
The use of real-time CPR feedback systems improves the quality of CC performed by individuals of all backgrounds, especially non-healthcare personnel. PAD with AED providing CPR feedback technologies may elevate the survival rate of out-of-hospital cardiac arrest and increase the likelihood of favorable outcomes.
Abstract 279: Effects of 2,3-Butanedione Monoxime Administration During Conventional Cardiopulmonary Resuscitation on Ischemic Contracture and Resuscitability in a Pig Model of Out-of-Hospital Cardiac Arrest
Authors: Lee ByungKook , Jeung Kyung Woon , Choi Sung Soo , Park Sang Wook , Yun Seong-Woo , Lee Sung Min , Heo Tag , Min Yong Il
Published: July 2021

Background:
Ischemic contracture compromises hemodynamic effectiveness of cardiopulmonary resuscitaton (CPR) and resuscitability. 2,3-Butanedione monoxime (BDM) reduced ischemic contracture by inhibiting actin-myosin cross-bridge formation in an isolated heart model. We investigated the effects of BDM on ischemic contracture and resuscitation outcomes in a pig model of out-of-hospital cardiac arrest (OHCA).

Methods:
After 15 min of untreated ventricular fibrillation followed by 8 min of basic life support, sixteen pigs were randomized to receive either 2 ml·kg
-1
of BDM solution (25 g·l
-1
) (BDM group) or 2 ml·kg
-1
of saline (control group) during advanced cardiac life support (ACLS). ACLS was continued until restoration of spontaneous circulation (ROSC) or until 12 min had lapsed since the start of ACLS. To obtain a long axis view of left ventricle (LV) using a transesophageal echocardiography (TEE) probe during CPR, a skin incision was made to the right of the xiphoid process and a pocket extending 4-5 cm under the sternum was made to ensure a free passage of the TEE probe. The primary outcome was ROSC and the secondary outcomes were LV wall thickness and chamber area.

Results:
There was a trend toward a higher rate of ROSC in the BDM group (8 of 8 versus 4 of 8,
p
= 0.077). During the ACLS, the control group showed an increase in LV wall thickness from 10.0 cm (10.0-10.8) to 13.0 cm (13.0-13.0) and a decrease in LV chamber area from 8.13 cm
2
(7.59-9.29) to 7.47 cm
2
(5.84-8.43). In contrast, the BDM group showed a decrease in the LV wall thickness from 10 cm (9.0-10.8) to 8.5 cm (7.0-9.8) and an increase in the LV chamber area from 9.86 cm
2
(7.22-12.39) to 12.15 cm
2
(8.02-14.40). Mixed model analyses on LV wall thickness and LV chamber area revealed significant effects for group and significant group-time interactions.

Conclusions:
BDM administered during cardiopulmonary resuscitation reversed ischemic contracture and tended to improve the resuscitability in a pig model of OHCA.
Abstract 280: Association of Bystander CPR Rates with County-Level Median Household Income in Pennsylvania
Authors: Li Kam Ching , Griff Julie E , Heisler Elizabeth K , Grossestreuer Anne V , Leary Marion , Abella Benjamin S , Becker Lance B
Published: July 2021

Background:
Each year, >300,000 people suffer from out-of-hospital cardiac arrest (OHCA) in the U.S. Studies have shown that bystander CPR (BCPR) can greatly increase a victim’s chance of survival, yet the frequency of BCPR may vary as a byproduct of various demographic factors. Over 10,000 OHCAs occur in Pennsylvania each year across 67 counties.

Objective:
We sought to determine the association of bystander CPR rate with county-level median household income, as well as related factors, such as education level, persons below poverty status, and population density.

Methods:
Data were obtained from the Cardiac Arrest Registry to Enhance Survival (CARES) for Pennsylvania from 1/2012-12/2013 to determine rate of BCPR and return of spontaneous circulation (ROSC) by county. Demographic information regarding education level, median household income and population density were obtained from 2010 U.S. Census data. Counties were grouped into quartiles by lowest to highest rates of BCPR. Results from the lowest-performing were compared to the highest-performing quartile, with statistical analysis using STATA v11 (StataCorp, College Station, Texas).

Results:
A total of 7137 cases were included distributed across 47 counties. Mean age of patients was 63.7 years, 40.1% were female, and VF/VT was the initial rhythm in 19.7%. Median BCPR rate for the lowest-performing quartile was 7% (IQR 0%-26.5%). Median BCPR rate for the highest-performing quartile was 50.4% (IQR 46.95%-56%). Median ROSC rate for the lowest-performing quartile was 1.5% (IQR 0%-20%). Median ROSC rate for the highest-performing quartile was 23.3% (IQR 20.8%-33.3%). Median household income in the lowest-performing quartile was significantly lower than in the highest-performing quartile ($43611 ± $5038 v $50225 ± $6661, p = 0.023). Education level, persons below poverty status, and population density were not shown to have a significant association with BCPR rate. BCPR rate was positively associated with ROSC rate (p=0.001).

Conclusions:
BCPR rates are significantly higher in counties with higher median household income. Higher BCPR rates are associated with higher rates of ROSC. These findings have important implications for statewide public health efforts to improve arrest survival.
Abstract 307: The Velocity of Increasing End-Tidal CO
2
Immediately Following Resuscitation Is Associated with Postresuscitation Myocardial Function
Authors: Yin Lu , Qian Jie , Yang Min , Gong Ping , Yang Zhengfei , Wu Xiaobo , Cahoon Jena , Tang Wanchun
Published: July 2021

Introduction:
End-tidal CO2 (ETCO2) serves as a sensitive indicator of hemodynamic efficacy during CPR and therefore predicts the success of resuscitation. In the present study, we investigated the relationship between the velocity of increasing ETCO2 immediately after successful resuscitation and post resuscitation myocardial function.

Hypothesis:
The velocity of increasing ETCO2 immediately following resuscitation is associated with the severity of post resuscitation myocardial dysfunction.

Methods:
Twenty rats were randomly assigned to one of two groups: (1) short duration of cardiac arrest (CA) (n = 10): ventricular fibrillation (VF) was untreated for 4 mins prior to 6 mins of CPR; (2) long duration of CA (n = 10): VF was untreated for 8 mins followed by 8 mins of CPR. After successful resuscitation, the first 20 secs of ETCO2 were analyzed. The velocity of ETCO2 changes was defined as the difference of the maximum and minimum ETCO2 value divided by the duration between the two ETCO2 values. Ejection fraction (EF) was measured by echocardiography at 8 hrs after resuscitation.

Results:
Increasing ETCO2 immediately following successful resuscitation was observed in all rats. However, the velocity of ETCO2 increasing in the group of short duration of CA was significantly faster than the group of long duration. This was associated with significantly greater EF at 8 hrs after resuscitation (Table). A close correlation between the velocity of increasing ETCO2 and EF was demonstrated (r=0.70, p<0.01) (Figure).

Conclusion:
The velocity of increasing ETCO2 immediately following resuscitation is associated with post resuscitation myocardial function.
Abstract 319: Mild Hypothermia Preserves Cerebral Cortex Microcirculation After Resuscitation in a Rat Model of Cardiac Arrest
Authors: Gong Ping , Zhao Shen , Wang Jiangang , Qian Jie , Yang Zhengfei , Wu Xiaobo , Cahoon Jena , Duggal Neil , Tang Wanchun
Published: July 2021

Introduction:
Mild hypothermia is one of the effective treatments in comatose patients after cardiac arrest. However, its neuroprotective mechanism is not fully clear. In the present study, we investigated the effect of mild hypothermia on cerebral cortex microcirculation and cerebral oxygen extraction ratio (CERO2).

Hypothesis:
Mild hypothermia is associated with an improved cerebral cortex microcirculation and a decreased CERO2.

Methods:
Twenty-five male Sprague-Dawley rats were randomized into 3 groups: hypothermic (HT, n=10), normothermic (NT, n=10) or sham control group (SC, n=5). Ventricular fibrillation was electrically induced and untreated for 8 mins, followed by 8 mins of precordial compressions and mechanical ventilations. Core temperature was reduced to 33±0.5°C at 14 mins after return of spontaneous circulation (ROSC) with a combination of ice packs, an electrical fan and a cooling blanket. The temperature was maintained at 33°C for 8 hrs. Hemodynamics, jugular venous and aortic blood gas, and cerebral cortex microcirculation were measured at baseline, 2, 4 and 8 hrs after ROSC.

Results:
Of the 20 experimental rats, 15 were successfully resuscitated. There was no significant difference in the rate of ROSC in the NT and HT groups (7/10 vs. 8/10; p>0.05). Microvascular flow index was significantly reduced at 2, 4 and 8 hrs after ROSC but was significantly improved by mild hypothermia (Figure 1). Mild hypothermia significantly reduced the CERO2 after ROSC (Figure 2).

Conclusions:
Mild hypothermia improves the cerebral cortex microcirculatory blood supply/oxygen uptake mismatching after ROSC, which may provide one additional mechanism of cerebral protection.
Abstract 346: Passive Ventilation During Cardiopulmonary Resuscitation Inside the Emergency Department
Authors: McDannold Robyn , Bronnenkant Tyler , Crowe Christopher , Silver Annemarie , Geheb Frederick , Herken Uli , Spaite Daniel , Bobrow Bentley
Published: July 2021

Background:
Continuing high quality chest compressions (CC) without interruption for active positive pressure ventilation (PPV) early in CPR has been demonstrated to improve patient outcomes in out-of-hospital cardiac arrest (OHCA). During the first minutes of CPR, passive oxygenation may be sufficient for oxygenating vital tissues. However, less is known about the later minutes of CPR. To evaluate this issue, in OHCA patients after hospital arrival, we quantified ventilation volumes during CCs in the ED.

Methods:
CPR quality metrics were obtained on patients who had CPR inside the ED with the E-Series defibrillator/monitor (Zoll Medical). Detailed ventilation data were obtained using a Non-Invasive Cardiac Output (NICO) Monitor (Philips/Respironics) with a CO2/flow sensor placed at the endotracheal tube. NICO waveform and breath-by-breath data were captured to measure ventilation volume associated with CCs.

Results:
Data files on 21 cardiac arrest patients who presented to the ED were included. [Male: 17, median age: 59 (IQR 47, 72)]. A total of 29,935 compressions (CCs) were analyzed [median depth 2.1 in (IQR=1.9, 2.5), median rate 126 CC/min (IQR=122-129). The median passive tidal volume during CCs was 5.8 mL, (IQR 3.4, 11.0). The highest volume was 124 mL, however 81% of the measured tidal volumes were <20 mL.

Conclusion:
This quantified analysis of ventilation volumes during chest compressions in the ED suggests that significant passive ventilation volumes may not occur later in CPR. Even in patients who were receiving effective compressions, passive tidal volumes were extremely low overall, suggesting that the value of compression only CPR may, in part, be due to the avoidance of the harmful effects of hyperventilation rather than any potential effect of passive ventilation.
Abstract 40: Should Bilateral Internal Thoracic Artery Grafting Be Used in Emergency Patients?
Authors: Ben-Gal Yanai , Mohr Rephael , Pevni Dimitri , Ganiel Amir , Kramer Amir , Nesher Nahum , Nevo Avner , Paz Yossi , Medalion Benjamin
Published: July 2021

HYPOTHESIS:
Bilateral Internal Thoracic Artery (BITA) grafting is not often used in emergency coronary artery bypass grafting (CABG) due to questionable survival benefit ,relative complexity and increased risk of sternal infection compared to operations incorporating Single Internal Thoracic Artery (SITA).

The purpose of this study is to compare early and long term outcome of emergent patients undergoing BITA grafting, to that of emergent patients undergoing CABG with SITA

METHODS:
Four hundred thirty eight emergency patients underwent BITA grafting between 1996 and 2008. They were compared with 339 emergency patients who underwent CABG with SITA

RESULTS:
Occurrence of female gender (18.5% vs. 29.5%, P< 0.001, in the BITA and SITA groups, respectively), diabetes (25.3% vs. 38.6%, P< 0.001), age 70+ (61.0% vs.39.7%, P< 0.001), chronic obstructive pulmonary disease (5.7% vs.13.9%, P< 0.001) EF <30% (12.1% vs. 17.1%, P< 0.001), and chronic renal failure (7.1% vs. 17.1%, p< 0.001) was lower in the BITA group. On the other hand critical preoperative state (35.4% vs. 26.0%, P= 0.003), and recent myocardial infarction (39.5% vs. 32.7%, P= 0.031) were more prevalent among BITA patients. Euro score I of SITA patients was significantly higher (10.58 ± 4.1 vs.8.65 ± 3.5, P= 0.016).

Operative mortality (5.3% vs 7.4%, BITA vs. SITA), and sternal wound infections (2.7% vs. 2.1%) were not significantly different between groups.

Mean follow-up was 8.75 ± 4.75 years. Ten year survival (Kaplan-Meier) of SITA patients with euro score 11+ was similar to that of BITA patients with euro score 11+. (34% vs. 37%, log rank test) .However, Kaplan-Meier 10 year survival of BITA patients with euro score I of 10 or lower was significantly better(80% vs. 68%, , BITA and SITA groups, respectively , P= 0.012 ).Assignment to the BITA group in the subset with lower euro score was also associated with better propensity adjusted survival ( HR 4.8 p < 0.001, compared to the SITA group, COX model)

CONCLUSIONS:
This large cohort study shows that,BITA grafting may be used in emergency patients., In medium and low risk emergency patients long term outcome is better than that of patients treated with SITA
Abstract 62: Preserved Cerebral Microcirculation After Cardiac Arrest in an Asphyxial Rat Model
Authors: Secher Niels , Hansen Frederik B , Tønnesen Else , østergaard Leif , Granfeldt Asger
Published: July 2021

Introduction:
Cardiac arrest (CA) carries a dismal prognosis, mainly due to neurological injury. Studies have reported dysfunction of the sublingual microcirculation following cardiac arrest. The objective of the study was to investigate if this microcirculatory dysfunction is also present in the brain after cardiac arrest.

Methods:
Anesthetized, intubated, and ventilated, male Sprague-Dawley rats were randomized into two CA groups and two control groups and observed for 120 min or 360 min following return of spontaneous circulation (CA120min (n=8), Control120min (n=8), CA360min (n=8), and Control360min (n=8)). After ten minutes of ashpyxial induced CA animals were resuscitated using adrenalin and manual CPR. At the end of the observation period, cerebral microcirculation was evaluated by side stream dark field microscopy through a parietal craniotomy, and plasma samples were drawn for endothelial adhesion molecule and inflammatory marker analyses. Animals were monitored with invasive blood pressure, ECG and arterial blood gas samples throughout the study.

Results:
At the end of the observation period mean arterial pressure decreased significantly in the cardiac arrest groups being 55±12mmHg in the CA120min group and 51±9mmHg in the CA360min group compared to 85±8mmHg in the control groups, whereas PaCO2 was kept in the normal range and did not differ between groups. There was no difference between groups for total vessel density, perfused vessel density, proportion of perfused vessels, or microvascular flow index measured in the cerebral cortex. Plasma samples drawn 360 min after return of spontaneous circulation showed a significant increase in E-selectin, L-selectin, I-CAM1, IL-1β, IL-6, IL-10 and elastase compared to controls. Between the CA groups E-selectin and elastase showed an increase from 120 to 360 min after resuscitation (p<0.007).

Conclusion:
Despite a significantly lower mean arterial pressure and elevated levels of soluble endothelial adhesion molecules and inflammatory cytokines, side stream dark field revealed no changes in the cerebral microcirculation in the early post resuscitation period.
Abstract 67: Cardiac Arrest and Surgical Case Volume, Household Income and Availability of Trauma and Cardiac Surgery Are Associated with Higher Risk-Standardized Survival After Cardiac Arrest Among University Hospital Consortium Institutions in 2012
Authors: Kurz Michael C , Donnelly John P , Wang Henry E
Published: July 2021

Objective:
Wide variation exists in cardiac arrest survival. Historically cardiac arrest research has focused upon clinical pre-arrest and intra-arrest factors to explain this variation in outcomes. In-hospital post-arrest care is increasingly recognized as an important aspect of survival. We sought to identify hospital characteristics associated with improved cardiac arrest survival.

Methods:
We examined all participating hospitals in the University Hospital Consortium (UHC) clinical database with more than 25 adult cardiac arrests in 2012. Cases were identified using International Classification of Diseases, 9th Edition, code 427.5 (cardiac arrest) or 99.60 (CPR), excluding prisoners, pregnant patients, transfers, and hospice patients. We estimated hospital-specific risk-standardized survival rates (RSSRs) using hierarchical logistic regression, adjusting for individual risk of mortality. Institutions in the highest RSSR quartile were compared with those in the lowest three quartiles using Pearson chi-square tests of association.

Results:
UHC institutions admitted 3,686,296 patients in 2012, of which 33,700 patients experienced cardiac arrest. Overall survival was 42.3% (95% CI 41.8-42.9) with median RSSR of 42.7% (IQR 35.5-50.8). Hospitals in the highest quartile of RSSR had higher cardiac arrest volume (median 193 vs. 150, p-value 0.019), higher annual surgical operation volume (21,177 vs. 14,122, 0.007), cared for patients from catchment areas with higher household income ($60,753 vs. $56,424, 0.027), and were more likely to be a trauma (79% vs 59%, 0.024) or cardiac surgery center (91% vs 70%, 0.007). In addition, hospital size (477 vs 415 beds, 0.060) and teaching status (77% vs. 62%, 0.067) demonstrated a trend toward association with higher RSSR.

Conclusion:
Among hospitals in the UHC, those with higher cardiac arrest and surgical case volume, patient household income, and availability of trauma and cardiac surgery were associated with improved RSSR.
Abstract 82: Mechanical CPR Is Associated with Poor Neurologically Intact Survival in a Statewide Registry
Authors: Youngquist Scott , Ockerse Patrick , Stratford Chris , Taillac Peter
Published: July 2021

BACKGROUND:
Large, randomized trials have concluded that mechanical CPR (mech-CPR) is equivalent to manual CPR (man-CPR) with respect to outcomes from out-of-hospital cardiac arrest (OHCA). However, outside of such well-controlled settings, the performance of mech-CPR is uncertain. We sought to determine the association, if any, between mech-CPR use and outcomes in a large, statewide registry of cardiac arrest.

METHODS:
The Utah State CARES registry began collecting outcomes on all cardiac arrests in the state of Utah in July of 2012. We analyzed data from this registry to determine the comparative performance of resuscitations utilizing mech-CPR vs man-CPR. Neurologically-intact survival was defined as a Cerebral Performance Category score of 1 or 2.

RESULTS:
Mech-CPR was performed on 237/1,567 OHCAs (15%) during the 1.5 year period of analysis. The majority of devices used were of the load-distributing band type 213/237 (90%). Neurologically-intact survival was 10/237 (4%) in the cohort receiving mech-CPR vs 149/1,330 (11%) in the cohort receiving man-CPR. When controlling for Utstein variables (TABLE), mech-CPR was associated with significantly reduced odds of neurologically-intact survival, with an adjusted odds ratio 0.4 (95% CI 0.2-0.9).

CONCLUSIONS:
We observed a statistically significant association between mech-CPR use during resuscitation and reduced odds of neurologically-intact survival in our statewide cardiac arrest database. Outside of randomized trials, the resuscitation performance of mech-CPR devices may suffer from poor implementation or increased application to non-viable survivors. Residual confounding of this observational finding is also possible.
Abstract 9386: Ramp Biphasic Waveforms Have a Lower External Defibrillation Threshold
Authors: Huang Jian , Walcott Gregory P , Ideker Raymond E
Published: July 2021

Introduction:
We have previously shown that waveforms with an ascending ramp in both phases have a lower internal defibrillation threshold (DFT). The purpose of this study was to test whether waveforms with rectilinear, ascending and descending ramps in the second phase would reduce the DFT compared with a standard exponential biphasic waveform with external defibrillation shocks.

Methods:
In 6 pigs, DFTs were determined for 10 waveforms: a standard truncated exponential biphasic waveform with 60% tilt (Fig 1, #1) and 9 biphasic waveforms with an 8 ms ascending ramp 1st phase and one of 3 rectilinear, ascending ramp or descending ramp 2nd phases. The 3 rectilinear 2nd phases were: 1 ms, 200% of peak voltage of phase 1 (#2); 2 ms, same voltage as phase (#3); 3 ms, half the voltage of phase 1 (#4). The 3 ascending ramp 2nd phases were: 2 ms, 200% of voltage of phase 1(#5); 3 ms, same voltage as phase 1(#6); 4.5 ms, half the voltage of phase 1(#7). The 3 descending ramp 2nd phases were: 2 ms, 200% of voltage of phase 1(#8); 3 ms, same voltage as phase 1(#9); 4.5 ms, half the voltage of phase 1(#10).

Results:
Phase 2 ascending ramp (#7) and descending ramp (#8, #9) waveforms had the lowest DFTs, which were significantly smaller than for the truncated exponential waveform. (Fig 1, *indicates p<0.05).

Conclusions:
Waveforms with a ramp in phase 2 (#7, #8, #9) have a lower DFT.