A dumbbell rescue stent graft facilitates clamp-free repair of aortic injury in a porcine model.

Objective: Noncompressible torso hemorrhage is a high-mortality injury. We previously reported improved outcomes with a retrievable rescue stent graft to temporize aortic hemorrhage in a porcine model while maintaining distal perfusion. A limitation was that the original cylindrical stent graft design prohibited simultaneous vascular repair, given the concern for suture ensnarement of the temporary stent. We hypothesized that a modified, dumbbell-shaped design would preserve distal perfusion and also offer a bloodless plane in the midsection, facilitating repair with the stent graft in place and improve the postrepair hemodynamics. Methods: In an Institutional Animal Care and Use Committee-approved terminal porcine model, a custom retrievable dumbbell-shaped rescue stent graft (dRS) was fashioned from laser-cut nitinol and polytetrafluoroethylene covering and compared with aortic cross-clamping. Under anesthesia, the descending thoracic aorta was injured and then repaired with cross-clamping (n = 6) or dRS (n = 6). Angiography was performed in both groups. Operations were divided into phases: (1) baseline, (2) thoracic injury with either cross-clamp or dRS deployed, and (3) recovery, after which the clamp or dRS were removed. Target blood loss was 22% to simulate class II or III hemorrhagic shock. Shed blood was recovered with a Cell Saver and reinfused for resuscitation. Renal artery flow rates were recorded at baseline and during the repair phase and reported as a percentage of cardiac output. Phenylephrine pressor requirements were recorded. Results: In contrast with cross-clamped animals, dRS animals demonstrated both operative hemostasis and preserved flow beyond the dRS angiographically. Recovery phase mean arterial pressure, cardiac output, and right ventricular end-diastolic volume were significantly higher in dRS animals (P = .033, P = .015, and P = .012, respectively). Whereas distal femoral blood pressures were absent during cross-clamping, among the dRS animals, the carotid and femoral MAPs were not significantly different during the injury phase (P = .504). Cross-clamped animals demonstrated nearly absent renal artery flow, in contrast with dRS animals, which exhibited preserved perfusion (P<.0001). Femoral oxygen levels (partial pressure of oxygen) among a subset of animals further confirmed greater distal oxygenation during dRS deployment compared with cross-clamping (P = .006). After aortic repair and clamp or stent removal, cross-clamped animals demonstrated more significant hypotension, as demonstrated by increased pressor requirements over stented animals (P = .035). Conclusions: Compared with aortic cross-clamping, the dRS model demonstrated superior distal perfusion, while also facilitating simultaneous hemorrhage control and aortic repair. This study demonstrates a promising alternative to aortic cross-clamping to decrease distal ischemia and avoid the unfavorable hemodynamics that accompany clamp reperfusion. Future studies will assess differences in ischemic injury and physiological outcomes. Clinical Relevance: Noncompressible aortic hemorrhage remains a high-mortality injury, and current damage control options are limited by ischemic complications. We have previously reported a retrievable stent graft to allow rapid hemorrhage control, preserved distal perfusion, and removal at the primary repair. The prior cylindrical stent graft was limited by the inability to suture the aorta over the stent graft owing to risk of ensnarement. This large animal study explored a dumbbell retrievable stent with a bloodless plane to allow suture placement with the stent in place. This approach improved distal perfusion and hemodynamics over clamp repair and heralds the potential for aortic repair while avoiding complications.

Resource Use and Economic Implications of Remote Monitoring With Subcutaneous Cardiac Rhythm Monitors.

OBJECTIVES: This study reports resource use and economic implications of rhythm monitoring with subcutaneous cardiac rhythm monitors (SCRMs). BACKGROUND: SCRMs generate a substantial amount of data that requires timely adjudication for appropriate clinical care. Resource use for SCRM monitoring is not known. METHODS: The study included consecutive transmissions during 4 weeks from 1,811 SCRMs. Resource use was quantified by assessment of time commitment of device clinic personnel and electrophysiologists for data adjudication. Incidence and characteristics of false positive (FP) episodes were assessed. Impact of custom programming for arrhythmia detection on incidence of FP episodes and resource use was analyzed. RESULTS: A total of 1,457 transmissions (alerts = 462; full downloads = 995) were received during study period. Average device clinic personnel time for adjudication of 1 transmission was 15 ± 6 min. This totaled to 364 h spent (2.3 full-time staff) over the 4-week period, which translated into a salary cost of $12,000 U.S. dollars (USD). Average time spent by an electrophysiologist for 1 transmission was 1.5 ± 1 min and totaled to 37 h for 4 weeks, which translated into an estimated cost of $9,600 USD. Of 1,457 total transmissions, 512 (35%) represented multiple transmissions from the same patients, which resulted in no additional reimbursement. Incidence of FP episodes in the entire cohort was 50% and was variable in alert (60%) and full download (49%) (p = 0.04) transmissions. When SCRMs with manufacturer suggested nominal programming and institutional custom programming were compared, there was a reduction in FP episodes (55% vs. 16%; p = 0.01), which translated to a 34% reduction in resource use for data adjudication. CONCLUSIONS: SCRM data adjudication requires significant resources. Custom programming for SCRMs may overcome the data deluge.

Incidence of pacing-induced cardiomyopathy in pacemaker-dependent patients is lower with leadless pacemakers compared to transvenous pacemakers.

INTRODUCTION: Frequent right AQ4ventricular pacing (≥40%) with a transvenous pacemaker (TVP) is associated with the risk of pacing-induced cardiomyopathy (PICM). Leadless pacemakers (LPs) have distinct physical and mechanical differences from TVP. The risk of PICM with LP is not known. To identify incidence, predictors, and long-term outcomes of PICM in LP and TVP patients. METHODS: The study comprised all pacemaker-dependent patients with LP or TVP who had left ventricular ejection fraction (LVEF) of ≥50 from 2014 to 2019. The incidence of PICM (≥10% LVEF drop) was assessed with an echocardiogram. Predictors for PICM were identified using multivariate analysis. Long-term outcomes after cardiac resynchronization (CRT) were assessed in both groups. RESULTS: A total of 131 patients with TVP and 67 with LP comprised the study. All patients in the TVP group and the majority in the LP group underwent atrioventricular node ablation. The mean follow-up duration in TVP and LP groups was 592 ± 549 and 817 ± 600 days, respectively. A total of 18 (13.7%) patients in TVP and 2 (3%) in LP developed PICM after a median duration of 254 (interquartile range: 470) days. The incidence of PICM was significantly higher with TVP compared with LP (p = .02). TVP as pacing modality was a positive (odds ratio [OR]: 1.07) while age was negative (OR: 0.94) predictor for PICM on multivariable analysis. Both patients in LP and all except two in the TVP group responded to CRT. CONCLUSION: Incidence of PICM is significantly lower with LP compared with TVP in pacemaker-dependent patients. Age and TVP as pacing modality were predictors for PICM.

How to minimize peri-procedural complications during subcutaneous defibrillator implant?

INTRODUCTION: Subcutaneous defibrillator (S-ICD) is the latest development in the clinically available devices for sudden cardiac death prevention. Experience from pivotal trials and post-marketing studies has proven the feasibility and safety of S-ICD. Extra-cardiac location of S-ICD obviates the need for transvenous leads which translates into lower incidence of lead-related complications and systemic infections. This is a review on peri-procedural interventions to minimize complications associated with S-ICD during implant and follow-up. AREAS COVERED: This paper will highlight the results of pertinent studies related to perioperative management of S-ICD and review the approaches to minimize the risk of complications such as hematoma at the pulse generator location, unsuccessful defibrillation due to suboptimal S-ICD lead and generator position, postoperative pain, inappropriate shocks due to T wave oversensing and interaction with concomitant cardiac implantable devices. An extensive literature search was performed to identify the relevant articles. EXPERT COMMENTARY: The use of S-ICD is expanding, and the published results suggest a preferential use of such devices for younger patients and those with a potential risk of infection from intravascular devices. The perioperative management of S-ICD has significantly evolved during a decade of experience. Contemporary experience suggests that these procedures are associated with minimal complications.

Approaches to Minimizing Periprocedural Complications During Subcutaneous Implantable Cardioverter-defibrillator Placement.

The subcutaneous implantable cardioverter-defibrillator (S-ICD) is the latest option among devices clinically available for the prevention of sudden cardiac death, with experience from previous trials and postmarketing studies supporting the feasibility and safety of this kind of system. The extracardiac positioning of the S-ICD obviates the need for transvenous leads, which translates into lower incidence rates of lead-related complications and systemic infections. This review will highlight the results of pertinent studies related to the perioperative management of S-ICDs and review potential approaches to minimizing the risk of complications such as hematoma at the pulse generator location, unsuccessful defibrillation due to suboptimal S-ICD lead and generator positioning, and postoperative pain. An extensive literature search using PubMed was conducted to identify relevant articles.

Incidence of false-positive transmissions during remote rhythm monitoring with implantable loop recorders.

BACKGROUND: Implantable loop recorder (ILR) is preferred strategy for prolonged rhythm monitoring. OBJECTIVE: The purpose of this study was to report the incidence and causes of false-positive (FP) diagnoses during remote monitoring with ILR. METHODS: During a 4-week study period, all consecutive remote transmissions in patients with ILR (Reveal LINQ, Medtronic) implanted for atrial fibrillation (AF) surveillance, cryptogenic stroke (CS), and syncope were reviewed. A nurse specializing in device management and an electrophysiologist adjudicated all transmissions. Primary endpoint of the study was incidence of FP in patients with AF, CS, and syncope. RESULTS: A total of 695 remote transmissions (scheduled downloads: 414; Alerts: 281) sent from 559 patients were adjudicated. The majority of patients had ILR for AF surveillance (n = 321), followed by CS (n =168) and syncope (n = 70) with nominal programming for rhythm diagnosis. Incidence of FP transmissions during the study period was 46%, 86%, and 71% in patients with AF, CS, and syncope, respectively. Incidence of FP transmissions was higher in patients with CS and syncope than in patients with AF (P <.001). For scheduled transmissions, primary causes of FP were signal dropout and undersensing; for alert transmissions, primary reasons for FP were premature atrial and ventricular ectopy. CONCLUSION: Incidence of FP during remote monitoring with nominal settings on this ILR was substantial, ranging from 46% to 86% depending on the indication for implantation. Adjudication of these transmissions required a considerable time commitment from electrophysiologists and device clinic personnel but would be required to avoid misdiagnosis and potential errors in clinical management.

Feasibility and safety of same day subcutaneous defibrillator implantation and send home (DASH) strategy.

PURPOSE: To assess the feasibility and safety of same-day discharge after S-ICD implantation by implementing a specific analgesia protocol and phone follow-up. METHODS: Consecutive patients presenting for outpatient S-ICD implantation were enrolled between 1/1/2018 and 4/30/2019. An analgesia protocol included pre-operative acetaminophen and oxycodone, intraoperative local bupivacaine, and limited use of oxycodone-acetaminophen at discharge. The primary outcome was successful same-day discharge. Numerical Pain Rating Scale (NPRS) on postoperative day (POD) 1, 3, 14, and 30 and any unplanned health care visits during the 1-month follow-up period were assessed. RESULTS: Out of 53 potentially eligible S-ICD patients, 49 patients (92.5%) were enrolled and successfully discharged on the same day. Mean age of these 49 patients was 47 ± 14 years. There were no acute procedural complications. Severe pain (NPRS ≥ 8) on POD 0, 1, and 3 was present in 14.3%, 14.3%, and 8.2% of patients, respectively. The total in-hospital stay was 534 ± 80 min. Four unplanned visits (8%) due to cardiac or device-related issues occurred during 1-month follow-up, including 2 patients with heart failure exacerbation, one patient with an incisional infection, and one patient with inappropriate shocks. CONCLUSIONS: With the appropriate institutional protocol including specific analgesics and phone follow-up, same-day discharge after outpatient S-ICD implantation is feasible and appears safe for most patients.. Device-related pain can be severe in the first 3 days post-implantation and can be successfully treated with limited supply of narcotic medications.

Implantation of subcutaneous defibrillator is feasible and safe with monitored anesthesia care.

BACKGROUND: The perioperative anesthesia care during subcutaneous implantable cardioverter-defibrillator (S-ICD) implantation is still evolving. OBJECTIVE: To assess the feasibility and safety of S-ICD implantation with monitored anesthesia care (MAC) versus general anesthesia (GA) in a tertiary care center. METHODS: This is a single-center retrospective study of patients undergoing S-ICD implantation between October 2012 and May 2019. Patients were categorized into MAC and GA group based on the mode of anesthesia. Procedural success without escalation to GA was the primary endpoint of the study, whereas intraprocedural hemodynamics, need of pharmacological support for hypotension and bradycardia, length of the procedure, stay in the post-anesthesia care unit, and postoperative pain were assessed as secondary endpoints. RESULTS: The study comprises 287 patients with MAC in 111 and GA in 176 patients. Compared to MAC, patients in GA group were younger and had a higher body mass index. All patients had successful S-ICD implantation. Only one patient (0.9%) in the MAC group was converted to GA. Despite a similar baseline heart rate (HR) and mean arterial blood pressure (MAP) in both groups, patients with GA had significantly lower HR and MAP during the procedure and more frequently required pharmacological hemodynamic support. Length of the procedure, stay in the postanesthesia care unit, and postoperative pain was similar in both groups. CONCLUSION: This retrospective experience suggests that implantation of S-ICD is feasible and safe with MAC. Use of GA is associated with more frequent administration of hemodynamic drugs during S-ICD implantation.

Projecting Cost Containment in the Operating Room Utilizing Incentivized Strategies to Reduce Healthcare Cost.

INTRODUCTION: Streamlining healthcare in United States is of paramount concern while maintaining standards of quality and safety. Incentivizing change may be even more effective in driving such measures. At Nationwide Children's Hospital, we incentivize cost savings directly to the healthcare team member. In this project, we evaluated a simple substitution of a buretrol for Y-type tubing based on weight rather than age cutoffs. METHODS: This was deemed a quality improvement project and therefore exempt from Institutional Review Board approval. We obtained costs of Y-type tubing versus buretrols. We interrogated the electronic medical record to quantify case volume in the main operating room according to age and weight. We calculated our costs to compare our current practice of using buretrol fo age ≤ 12 years and the planned practice of using buretrol for weight < 20 kg. RESULTS: We identified 28,875 children ages 0-12 (60% weight <20kg) and 6,301 children ages 13-18 (0.1% weight <20kg) undergoing procedures in the main operating rooms over a 1-year period.. A unit cost savings of $4.40 substituting Y-type tubing for a buretrol was determined. Transitioning from age-based to weight-based criteria for buretrol use was determined to potentially save $51,260 over the period reviewed. CONCLUSIONS: Simple changes can impact efficiency and cost in healthcare. It is important to consider incentivizing such measures to help drive these changes. In the future, with more incentivized measures, hopefully we can successfully make an impact of efficiency and cost of healthcare in United States without compromising safety or quality.

Use of a Piglet Model for the Study of Anesthetic-induced Developmental Neurotoxicity (AIDN): A Translational Neuroscience Approach.

Anesthesia cannot be avoided in many cases when surgery is required, particularly in children. Recent investigations in animals have raised concerns that anesthesia exposure may lead to neuronal apoptosis, known as anesthesia-induced developmental neurotoxicity (AIDN). Furthermore, some clinical studies in children have suggested that anesthesia exposure may lead to neurodevelopmental deficits later in life. Nonetheless, an ideal animal model for preclinical study has yet to be developed. The neonatal piglet represents a valuable model for preclinical study, as they share a striking number of developmental similarities with humans. The anatomy and physiology of piglets allow for implementation of rigorous human perioperative conditions in both survival and non-survival procedures. Femoral artery catheterization allows for close monitoring, thus enabling prompt correction of any deviation of the piglet's vital signs and chemistries. In addition, there are multiple developmental similarities between piglets and human neonates. The techniques required to use piglets for experimentation will require experience to master. A pediatric anesthesiologist is a critical member of the investigative team. We describe, in a general sense, the appropriate use of a piglet model for neurodevelopmental study.

A novel, clinically relevant use of a piglet model to study the effects of anesthetics on the developing brain.

BACKGROUND: Anesthesia-induced neurotoxicity research in the developing brain must rely upon an unimpeachable animal model and a standardized treatment approach. In this manner, identification of mechanisms of action may be undertaken. The goal of this study was to develop a novel, clinically relevant, translational way to use a piglet model to investigate anesthesia effects on the developing brain. METHODS: 29 newborn piglets were assigned to either: (1) control (no intervention, n = 10); (2) lipopolysaccharide (LPS; positive inflammatory control, n = 9); or (3) isoflurane anesthesia (n = 10). Positive inflammatory control animals were given 100 mcg/kg LPS from Escherichia coli intraperitoneally (IP) on the same day as those receiving isoflurane. Isoflurane was administered for 3 h while care was taken to ensure human perioperative conditions. To establish a clinical scenario, each animal was intubated and monitored with pulse oximetry, invasive and non-invasive blood pressure, electrocardiogram, temperature, end-tidal CO2, anesthetic concentration, and iSTAT blood analysis. All animals were sacrificed after 48 h using transcardiac perfusion of ice-cold, heparinized phosphate buffered saline (PBS) followed by 4 % paraformaldehyde (PFA). Brains were collected and histopathological analysis focused on the entorhinal cortex looking for degenerative changes due to its critical role in learning and memory. Reliable identification of entorhinal cortex was achieved by using colored ink on the surface of the brains, which was then cross-referenced with microscopic anatomy. Hematoxylin & eosin-stained high-power fields was used to quantify cells. ImageJ™ (National Institutes of Health, Bethesda, MD, USA) was used to count absolute number of progenitor glial cells (PGC) and number of PGCs per cluster. Immunohistochemistry was also utilized to ensure positive identification of cellular structures. RESULTS: Histopathological sections of 28 brains were analyzed. One animal in the LPS group died shortly after administration, presumably from inadvertent intravascular injection. There was an acute basal ganglia ischemic infarct in one isoflurane-treated animal. A large number of small, round nucleated cells were seen throughout layer II of the entorhinal cortex in all animals. These cells were identified as PGCs using immunohistochemistry and light microscopy. Although there was no difference in the absolute number of PGCs between the groups, animals given isoflurane or LPS demonstrated a significant increase in cells forming 'clusters' in the entorhinal cortex. An apparent change in the pattern of doublecortin labeling also suggests changes in neuronal precursors and undifferentiated neurons. CONCLUSIONS: This study represents the first novel use of a clinically relevant neonatal piglet model to study anesthesia effects on the developing brain. LPS induces neuroinflammation, and this is a potential mechanism for LPS and perhaps isoflurane in causing a change in progenitor cell distribution. We postulate that the isoflurane-induced change in glial progenitor cell distribution could have important implications for cell differentiation, maturation and neural circuit behavior in the rapidly developing brain.