Left internal mammary artery access for embolization of the left subclavian artery in a patient with type II endoleak after thoracic endovascular aortic repair for a ruptured right-sided aortic arch aneurysm

A 65-year-old woman had presented with a ruptured type B intramural hematoma associated with a right-sided aortic arch aneurysm, a large Kommerell diverticulum (KD) and an aberrant left subclavian artery (LSA). She underwent total aortic arch replacement with elephant trunk, thoracic endovascular aortic repair, and LSA ligation distal to the left vertebral artery. She subsequently developed a brisk type II endoleak into the KD via retrograde flow from the left vertebral artery. Percutaneous access of the left internal mammary artery with coil embolization of the proximal LSA and KD was performed. At 5 years, computed tomography angiogram showed complete thoracic aortic remodeling without an endoleak. The results from the present case have illustrated the novel use of the left internal mammary artery as an alternative access for LSA embolization in patients with type II endoleak and limited access options.

Geoeconomic variations in epidemiology, ventilation management, and outcomes in invasively ventilated intensive care unit patients without acute respiratory distress syndrome: a pooled analysis of four observational studies

Background

Geoeconomic variations in epidemiology, the practice of ventilation, and outcome in invasively ventilated intensive care unit (ICU) patients without acute respiratory distress syndrome (ARDS) remain unexplored. In this analysis we aim to address these gaps using individual patient data of four large observational studies.

Methods

In this pooled analysis we harmonised individual patient data from the ERICC, LUNG SAFE, PRoVENT, and PRoVENT-iMiC prospective observational studies, which were conducted from June, 2011, to December, 2018, in 534 ICUs in 54 countries. We used the 2016 World Bank classification to define two geoeconomic regions: middle-income countries (MICs) and high-income countries (HICs). ARDS was defined according to the Berlin criteria. Descriptive statistics were used to compare patients in MICs versus HICs. The primary outcome was the use of low tidal volume ventilation (LTVV) for the first 3 days of mechanical ventilation. Secondary outcomes were key ventilation parameters (tidal volume size, positive end-expiratory pressure, fraction of inspired oxygen, peak pressure, plateau pressure, driving pressure, and respiratory rate), patient characteristics, the risk for and actual development of acute respiratory distress syndrome after the first day of ventilation, duration of ventilation, ICU length of stay, and ICU mortality.

Findings

Of the 7608 patients included in the original studies, this analysis included 3852 patients without ARDS, of whom 2345 were from MICs and 1507 were from HICs. Patients in MICs were younger, shorter and with a slightly lower body-mass index, more often had diabetes and active cancer, but less often chronic obstructive pulmonary disease and heart failure than patients from HICs. Sequential organ failure assessment scores were similar in MICs and HICs. Use of LTVV in MICs and HICs was comparable (42·4% vs 44·2%; absolute difference –1·69 [–9·58 to 6·11] p=0·67; data available in 3174 [82%] of 3852 patients). The median applied positive end expiratory pressure was lower in MICs than in HICs (5 [IQR 5–8] vs 6 [5–8] cm H₂O; p=0·0011). ICU mortality was higher in MICs than in HICs (30·5% vs 19·9%; p=0·0004; adjusted effect 16·41% [95% CI 9·52–23·52]; p<0·0001) and was inversely associated with gross domestic product (adjusted odds ratio for a US$10 000 increase per capita 0·80 [95% CI 0·75–0·86]; p<0·0001).

Interpretation

Despite similar disease severity and ventilation management, ICU mortality in patients without ARDS is higher in MICs than in HICs, with a strong association with country-level economic status.

Funding

No funding.

A more proximal landing zone is preferred for thoracic endovascular repair of acute type B aortic dissections

OBJECTIVES

Thoracic endovascular aortic repair (TEVAR) has become first line therapy for complicated acute type B aortic dissection (aTBAD). However, the strategy for optimal proximal landing zone remains to be determined. We compared early outcomes and late aortic-related adverse events in patients undergoing TEVAR for complicated aTBAD with endograft deployment in proximal landing zone 2 versus 3.

METHODS

We performed a retrospective chart review of adult patients undergoing TEVAR for complicated aTBAD within 6 weeks of diagnosis from 1/2008 to 12/2018. We excluded patients with connective tissue disorders and prior type A repair. Patients were divided into landing zone 2 TEVAR (Z2T) and zone 3 TEVAR (Z3T) groups. Z2 patients were divided between left subclavian artery (LSA) revascularization (Z2R) versus LSA coverage without revascularization (Z2C). Groups were compared for need for aortic re-intervention within 36 months of initial admission and freedom from aortic related adverse events and mortality (AREM), defined as need for aortic re-intervention, aortic-related death or rupture.

RESULTS

Eighty-three patients underwent TEVAR for complicated aTBAD within a mean of 4.1±7.8 days. 89.5% of patients had less than 2 cm of healthy proximal descending thoracic aorta. Landing zone was Z3T in 35 patients and 48 underwent Z2T: 10 Z2C and 38 Z2R. There were no differences between Z2T and Z3T in time from diagnosis to TEVAR, demographics, comorbidities and diameter aortic measurements. 30-day survival was 87.8%: 89.5% for Z2R, 88.6% for Z3 and 80.0 % for Z2C (p=0.610). Post-operative spinal cord ischemia rate was 3.7%: 2.7 % for Z2R, 0% for Z3T and 20.0% for Z2C (p=0.012). Post-operative thoracic aortic rupture was 2.2% in Z2 and 0 in Z3. Need for aortic re-intervention at 36 months post-TEVAR was lower for Z2T (10.4%) vs. Z3T (31.4%), p=0.025. Freedom from AREM at 36 months was higher in Z2T vs. Z3T - 87.5% vs. 68.6%, p= 0.048. Freedom from proximal re-intervention was higher in Z2T (95.8%) compared to Z3T (80.0%), p=0.019. Z3T deployment was predictive for AREM (OR:3.648,95%CI:1.161-11.465,p=0.027) and need for proximal re-intervention (OR: 5.542,95%CI:1.062-28.927,p=0.042).

CONCLUSION

Most patients with aTBAD have less than 2 cm of proximal healthy descending thoracic aorta. In patients treated for complicated aTBAD, zone 2 TEVAR is associated with a lower need for aortic re-intervention and aortic-related adverse events than zone 3 TEVAR. Patients may benefit from a more aggressive proximal landing zone with similar perioperative morbidity when zone 2 TEVAR is done with LSA revascularization.

Systemically Administered Hemostatic Nanoparticles for Identification and Treatment of Internal Bleeding

Internal bleeding is an injury that can be difficult to localize and effectively treat without invasive surgeries. Injectable polymeric nanoparticles have been developed that can reduce clotting times and blood loss, but they have yet to incorporate sufficient diagnostic capabilities to assist in identifying bleeding sources. Herein, polymeric nanoparticles were developed to simultaneously treat internal bleeding while incorporating tracers for visualization of the nanoparticles by standard clinical imaging modalities. Addition of 1,1'-dioctadecyl-3,3,3',3'-tetramethylindodicarbocyanine perchlorate (DiD; a fluorescent dye), biotin functionality, and gold nanoparticles to hemostatic polymeric nanoparticles resulted in nanoparticles amenable to imaging with near-infrared (NIR) imaging, immunohistochemistry, and X-ray computed tomography (CT), respectively. Following a lethal liver resection injury, visualization of accumulated nanoparticles by multiple imaging methods was achieved in rodents, with the highest accumulation observed at the liver injury site, resulting in improved survival rates. Tracer addition to therapeutic nanoparticles allows for an expansion of their applicability, during stabilization by first responders to diagnosis and identification of unknown internal bleeding sites by clinicians using standard clinical imaging modalities.

Lung Protective Effects of Low-Volume Resuscitation and Pharmacologic Treatment of Swine Subjected to Polytrauma and Hemorrhagic Shock

Hemorrhage is a common cause of death in the battlefield. Valproic acid (VPA) has been associated with improved outcomes in multiple models of trauma, when combined with isotonic fluid resuscitation. However, isotonic fluid administered in this setting is logistically impractical and may be associated with complications. In this study, we sought to evaluate the feasibility and immunologic impact of combining VPA treatment with low-volume hypertonic saline (HTS). In vivo: female Yorkshire swine were subjected to hemorrhage (40% total blood volume) and polytrauma (rib fracture and delayed liver injury). Animals were kept in shock for 30 minutes and resuscitated with (1) normal saline (NS, 3× hemorrhaged volume), (2) HTS (7.5% saline, 4 mL/kg), or (3) HTS + VPA (4 mg/kg; 150 mg/kg; n = 3/cohort). After 18 hours of observation, animals were euthanized and the lungs evaluated for acute injury and expression of myeloperoxidase (MPO) and caveolin-1 (Cav-1). In vitro: human umbilical vein endothelial cells (HUVECs) were exposed to anoxic conditions (5% CO₂, 95% N₂) for 16 hours in (1) normosmotic, (2) hyperosmotic (400 mOsm), or (3) hyperosmotic + VPA (4 mM) media. Immunohistochemistry and Western blots were performed to determine Cav-1 expression. Lungs from VPA-treated animals demonstrated decreased acute injury, MPO expression, and endothelial expression of Cav-1 when compared to lungs from animals resuscitated with NS or HTS alone. Similarly, HUVECs cultured in hyperosmotic media containing VPA demonstrated decreased expression of Cav-1. This study demonstrates that combined treatment with VPA and HTS is a viable strategy in hemorrhagic shock and polytrauma. Attenuation of lung injury following VPA treatment may be related to modulation of the inflammatory response.

Use of Drone Technology for Delivery of Medical Supplies During Prolonged Field Care

BACKGROUND

Care of trauma casualties in an austere environment presents many challenges, particularly when evacuation is not immediately available. Man-packable medical supplies may be consumed by a single casualty, and resupply may not be possible before evacuation, particularly during prolonged field care scenarios. We hypothesized that unmanned aerial drones could successfully deliver life-sustaining medical supplies to a remote, denied environment where vehicle or foot traffic is impossible or impractical.

METHODS

Using an unmanned, rotary- wing drone, we simulated delivery of a customizable, 4.5kg load of medical equipment, including tourniquets, dressings, analgesics, and blood products. A simulated casualty was positioned in a remote area. The flight was preprogrammed on the basis of grid coordinates and flew on autopilot beyond visual range; data (altitude, flight time, route) were recorded live by high-altitude Shadow drone. Delivery time was compared to the known US military standards for traversing uneven topography by foot or wheeled vehicle.

RESULTS

Four flights were performed. Data are given as mean (± standard deviation). Time from launch to delivery was 20.77 ± 0.05 minutes (cruise speed, 34.03 ± 0.15 km/h; mean range, 12.27 ± 0.07 km). Medical supplies were delivered successfully within 1m of the target. The drone successfully returned to the starting point every flight. Resupply by foot would take 5.1 hours with an average speed of 2.4km/h and 61.35 minutes, with an average speed of 12 km/h for a wheeled vehicle, if a rudimentary road existed.

CONCLUSION

Use of unmanned drones is feasible for delivery of life-saving medical supplies in austere environments. Drones repeatedly and accurately delivered medical supplies faster than other methods without additional risk to personnel or manned airframe. This technology may have benefit for austere care of military and civilian casualties.

Association Between Ratio of Fresh Frozen Plasma to Red Blood Cells During Massive Transfusion and Survival Among Patients Without Traumatic Injury

Importance

Hemostatic resuscitation has been shown to be beneficial for patients with trauma, but there is little evidence that it is equally beneficial for bleeding patients without trauma. The practice of a high transfusion ratio of fresh frozen plasma (FFP) to red blood cells (RBCs) has spread to other surgical and medical fields.

Objective

To identify whether ratio-based resuscitation in patients without trauma is associated with improved survival.

Design, Setting, and Participants

This study is a retrospective review of all massive transfusions provided in an urban academic hospital from January 1, 2009, through December 31, 2012. Massive transfusion was defined as the transfusion of at least 10 U of RBCs in the first 24 hours after a patient's admission to the operating room, emergency department, or intensive care unit. All patients who received massive transfusions within the study period and survived more than 30 minutes after hospital arrival were counted (n=865). Patients were grouped into those with trauma and those without trauma. Sources of data included the Research Patient Data Registry, patients' medical records, and blood bank records. All data collection occurred between April 26, 2013, and April 26, 2015. Data analysis took place from April 27, 2015, and June 22, 2016.

Main Outcomes and Measures

Examination of FFP:RBC transfusion ratios for patients without trauma.

Results

There were 865 massive transfusion events that occurred within 4 years, transfusing 16 569 U of RBCs, 13 933 U of FFP, 5228 U of cryoprecipitate, and 22 635 U of platelets. Most of these transfusions were received by patients without trauma (767 [88.7%]), by men (582 [67.3%]), and for intraoperative bleeding (544 [62.9%]). The FFP:RBC ratios of survivors and nonsurvivors were nearly identical: the ratio for survivors was 1:1.5 (interquartile range [IQR], 1:1.1-1:2.2) and for nonsurvivors was 1:1.4 (IQR, 1:1.1-1:1.9; P = .43). Among the 767 patients without trauma, there was no difference in the adjusted odds ratio (aOR) for 30-day mortality when comparing the high FFP:RBC ratio vs the low FFP:RBC ratio subgroups (aOR, 1.10; 95% CI, 0.72-1.70; P = .65). In vascular surgery, the aOR for death favored the high FFP:RBC ratio subgroup (aOR, 0.16; 95% CI, 0.03-0.79; P = .02). However, in general surgery and medicine, the aOR for death favored the low FFP:RBC ratio subgroup; general surgery: aOR, 4.27 (95% CI, 1.28-14.22; P = .02); medicine: aOR, 8.48 (95% CI, 1.50-47.75; P = .02).

Conclusions and Relevance

High FFP:RBC transfusion ratios are applied mostly to patients without trauma, who account for nearly 90% of all massive transfusion events. Thirty-day survival was not significantly different in patients who received a high FFP:RBC ratio compared with those who received a low ratio.

Histopathological assessment of OASIS Ultra on critical-sized wound healing: a pilot study

BACKGROUND

Dermatopathologists assess wounds secondary to trauma, infection, or oncologic resection that can be challenging to reconstruct. OASIS Ultra, an extracellular matrix, has been described for use in chronic and burn wounds. The aim of this pilot study is to assess wound healing in post-traumatic and infective wounds treated with OASIS using histological markers of repair.

MATERIALS AND METHODS

Adults with traumatic, infective or iatrogenic wound defects with size precluding primary closure were eligible. Half the wound was randomly assigned to receive OASIS plus standard therapy; the other half received standard of care (SOC) therapy. During dressing changes, standardized-scale photographs were taken and biopsies obtained. Histologic sections were reviewed for degree of acute inflammation and extent of tissue repair. Neutrophils, edema, hemorrhage, necrosis, fibroblasts, collagen density and neovascularization were semi-quantitatively assessed.

RESULTS

Forty-four skin biopsies from 7 patients with 10 acute wounds met eligibility criteria. Histologically, OASIS samples demonstrated improved acute inflammation scores compared to SOC. No patients experienced OASIS-related complications. OASIS-treated wound halves trended toward more wound contraction and improved tissue repair.

CONCLUSION

Our scoring system aids histopathological wound assessment. Treatment of critical-sized, post-traumatic, acute wounds with OASIS resulted in decreased inflammation, and potentially more advanced wound healing, compared to SOC.

Hydrophobically-modified chitosan foam: description and hemostatic efficacy

BACKGROUND

Trauma represents a significant public health burden, and hemorrhage alone is responsible for 40% of deaths within the first 24 h after injury. Noncompressible hemorrhage accounts for the majority of hemorrhage-related deaths. Thus, materials which can arrest bleeding rapidly are necessary for improved clinical outcomes. This preliminary study evaluated several self-expanding hydrophobically modified chitosan (HM-CS) foams to determine their efficacy on a noncompressible severe liver injury under resuscitation.

METHODS

Six HM-CS foam formulations (HM-CS1, HM-CS2, HM-CS3, HM-CS4, HM-CS5, and HM-CS6) of different graft types and densities were synthesized, characterized, and packaged into spray canisters using dimethyl ether as the propellant. Expansion profiles of the foams were evaluated in bench testing. Foams were then evaluated in vitro, interaction with blood cells was determined via microscopy, and cytotoxicity was assessed via live-dead cell assay on MCF7 breast cancer cells. For in vivo evaluation, rats underwent a 14 ± 3% hepatectomy. The animals were treated with either: (1) an HM-CS foam formulation, (2) CS foam, and (3) no treatment (NT). All animals were resuscitated with lactated Ringer solution. Survival, total blood loss, mean arterial pressures (MAP), and resuscitation volume were recorded for 60 min.

RESULTS

Microscopy showed blood cells immobilizing into colonies within tight groups of adjacent foam bubbles. HM-CS foam did not display any toxic effects in vitro on MCF7 cells over a 72 h period studied. Application of HM-CS foam after hepatectomy decreased total blood loss (29.3 ± 7.8 mL/kg in HM-CS5 group versus 90.9 ± 20.3 mL/kg in the control group; P <0.001) and improved survival from 0% in controls to 100% in the HM-CS5 group (P <0.001).

CONCLUSIONS

In this model of severe liver injury, spraying HM-CS foams directly on the injured liver surface decreased blood loss and increased survival. HM-CS formulations with the highest levels of hydrophobic modification (HM-CS4 and HM-CS5) resulted in the lowest total blood loss and highest survival rates. This pilot study suggests HM-CS foam may be useful as a hemostatic adjunct or solitary hemostatic intervention.

Use of a Totally Artificial Heart for a Complex Postinfarction Ventricular Septal Defect

The incidence of cardiac rupture complicating myocardial infarction has declined since the introduction of thrombolytic therapy. Despite the advances in the management of myocardial infarction, cardiac rupture remains an important cause of death among infarction-related fatalities. We discuss a patient who presented to our hospital with myocardial infarction and who subsequently developed a complex ventricular septal rupture, for which surgical repair was not feasible. Implantation of a CardioWest Total Artificial Heart (SynCardia Systems) allowed for immediate hemodynamic stabilization and served as a bridge to transplantation.

Percutaneous Ventricular Assist Device and Extracorporeal Membrane Oxygenation Support in a Patient with Postinfarction Ventricular Septal Defect and Free Wall Rupture

We describe the case of a 54-year-old woman with a postinfarction ventricular septal defect (VSD) and ventricular free wall rupture who was stabilized with a percutaneous ventricular assist device (pVAD) to allow for myocardial infarct stabilization. Following the rupture of the right ventricular free wall and cardiopulmonary arrest on hospital day 10, pVAD support was promptly converted to extracorporeal membrane oxygenation (ECMO) support for stabilization. After surgical repair was completed, pVAD support was continued for 4 days to allow recovery. The patient was discharged on postoperative day 11 and is alive and well 4 years later. Postinfarction VSD with free wall rupture may be salvaged with pVAD and ECMO support.

4-Substituted trinems as broad spectrum beta-lactamase inhibitors: structure-based design, synthesis, and biological activity

A wide variety of pathogens have acquired antimicrobial resistance as an inevitable evolutionary response to the extensive use of antibacterial agents. In particular, one of the most widely used antibiotic structural classes is the beta-lactams, in which the most common and the most efficient mechanism of bacterial resistance is the synthesis of beta-lactamases. Class C beta-lactamase enzymes are primarily cephalosporinases, mostly chromosomally encoded, and are inducible by exposure to some beta-lactam agents and resistant to inhibition by marketed beta-lactamase inhibitors. In an ongoing effort to alleviate this problem a series of novel 4-substituted trinems was designed and synthesized. Significant in vitro inhibitory activity was measured against the bacterial beta-lactamases of class C and additionally against class A. The lead compound LK-157 was shown to be a potent mechanism-based inactivator. Acylation of the active site Ser 64 of the class C enzyme beta-lactamase was observed in the solved crystal structures of two inhibitors complexes to AmpC enzyme from E. cloacae. Structure-activity relationships in the series reveal the importance of the trinem scaffold for inhibitory activity and the interesting potential of the series for further development.

Precursor of a beta-lactamase inhibitor: allyl (4S,8S,9R)-10-[(E)-ethylidene]-4-methoxy-11-oxo-1-azatricyclo[7.2.0.0(3,8)]undec-2-ene-2-carboxylate

The molecular structure of the title tricyclic compound, C(17)H(21)NO(4), which is the immediate precursor of a potent synthetic inhibitor [Lek157: sodium (8S,9R)-10-[(E)-ethylidene]-4-methoxy-11-oxo-1-azatricyclo[7.2.0.0(3,8)]undec-2-ene-2-carboxylate] with remarkable potency, provides experimental evidence for the previously modelled relative position of the fused cyclohexyl ring and the carbonyl group of the beta-lactam ring, which takes part in the formation of the initial tetrahedral acyl-enzyme complex. In this hydrophobic molecule, the overall geometry is influenced by C[bond]H...O intramolecular hydrogen bonds [3.046 (4) and 3.538 (6) A, with corresponding normalized H.O distances of 2.30 and 2.46 A], whereas the molecules are interconnected through intermolecular C[bond]H...O hydrogen bonds [3.335 (4)-3.575 (5) A].

Design, synthesis and bioactivity evaluation of tribactam beta lactamase inhibitors

Known carbapenem compounds with inhibitory effect towards beta-lactamase enzymes are formed from bicyclical beta lactam structural scaffolds. On the basis of results from theoretical computational methods and molecular modelling we have designed and developed a synthetic route towards novel, biologically active tricyclic derivatives of carbapenems.