Spinal Cord Infarction With Prolonged Femoral Venoarterial Extracorporeal Membrane Oxygenation.

OBJECTIVES: There have been sporadic reports of ischemic spinal cord injury (SCI) during venoarterial extracorporeal membrane oxygenation (VA-ECMO) support. The authors observed a troubling pattern of this catastrophic complication and evaluated the potential mechanisms of SCI related to ECMO. DESIGN: This study was a case series. SETTING: This study was performed at a single institution in a University setting. PARTICIPANTS: Patients requiring prolonged VA-ECMO were included. INTERVENTIONS: No interventions were done. This was an observational study. MEASUREMENTS AND MAIN RESULTS: Four hypotheses of etiology were considered: (1) hypercoagulable state/thromboembolism, (2) regional hypoxia/hypocarbia, (3) hyperperfusion and spinal cord edema, and (4) mechanical coverage of spinal arteries. The SCI involved the lower thoracic (T7-T12 level) spinal cord to the cauda equina in all patients. Seven out of 132 (5.3%) patients with prolonged VA-ECMO support developed SCI. The median time from ECMO cannulation to SCI was 7 (range: 6-17) days.There was no evidence of embolic SCI or extended regional hypoxia or hypocarbia. A unilateral, internal iliac artery was covered by the arterial cannula in 6/7 86%) patients, but flow into the internal iliac was demonstrated on imaging in all available patients. The median total flow (ECMO + intrinsic cardiac output) was 8.5 L/min (LPM), and indexed flow was 4.1 LPM/m2. The median central venous oxygen saturation was 88%, and intracranial pressure was measured at 30 mmHg in one patient, suggestive of hyperperfusion and spinal cord edema. CONCLUSIONS: An SCI is a serious complication of extended peripheral VA-ECMO support. Its etiology remains uncertain, but the authors' preliminary data suggested that spinal cord edema from hyperperfusion or venous congestion could contribute.

Stem Cell Therapy for Hypoplastic Left Heart Syndrome: Mechanism, Clinical Application, and Future Directions.

Hypoplastic left heart syndrome is a type of congenital heart disease characterized by underdevelopment of the left ventricle, outflow tract, and aorta. The condition is fatal if aggressive palliative operations are not undertaken, but even after the complete 3-staged surgical palliation, there is significant morbidity because of progressive and ultimately intractable right ventricular failure. For this reason, there is interest in developing novel therapies for the management of right ventricular dysfunction in patients with hypoplastic left heart syndrome. Stem cell therapy may represent one such innovative approach. The field has identified numerous stem cell populations from different tissues (cardiac or bone marrow or umbilical cord blood), different age groups (adult versus neonate-derived), and different donors (autologous versus allogeneic), with preclinical and clinical experience demonstrating the potential utility of each cell type. Preclinical trials in small and large animal models have elucidated several mechanisms by which stem cells affect the injured myocardium. Our current understanding of stem cell activity is undergoing a shift from a paradigm based on cellular engraftment and differentiation to one recognizing a primarily paracrine effect. Recent studies have comprehensively evaluated the individual components of the stem cells' secretomes, shedding new light on the intracellular and extracellular pathways at the center of their therapeutic effects. This research has laid the groundwork for clinical application, and there are now several trials of stem cell therapies in pediatric populations that will provide important insights into the value of this therapeutic strategy in the management of hypoplastic left heart syndrome and other forms of congenital heart disease. This article reviews the many stem cell types applied to congenital heart disease, their preclinical investigation and the mechanisms by which they might affect right ventricular dysfunction in patients with hypoplastic left heart syndrome, and finally, the completed and ongoing clinical trials of stem cell therapy in patients with congenital heart disease.

Early airway dehiscence: Risk factors and outcomes with the rising incidence of extracorporeal membrane oxygenation as a bridge to lung transplantation.

BACKGROUND: Anastomotic complications occur in 7% to 18% of lung transplant recipients, among which airway dehiscence (AD) is particularly catastrophic. Using multi-institutional registry data, this study compared preoperative recipient/donor risk factors and outcomes in patients with and without AD and analyzed the effect of extracorporeal membrane oxygenation (ECMO) on the incidence of AD. METHODS: Data on adult lung transplants from 2007 to 2017 were provided by the Scientific Registry of Transplant Recipients. Patients receiving isolated lobar transplantation and patients with unknown AD status were excluded. Multivariable logistic regression identified independent risk factors for AD. Kaplan-Meier curves and log-rank tests describe mortality and graft survival. RESULTS: Of 18 122 lung transplants, 275 (1.5%) experienced AD. While the incidence of ECMO steadily increased from 0.7% to 5.9% over the study period, the incidence of AD remained relatively constant. Multivariable analysis revealed recipient male gender and prolonged ( > 48 hours) posttransplant mechanical ventilation as independent predictive factors for AD, while advanced donor age and single left lung transplant were protective factors. Recipient chronic steroid use, recipient diabetes, donor diabetes, and donor smoking history were not predictive of AD. Mortality and graft failure were significantly worse in the AD group. CONCLUSIONS: Despite increased ECMO utilization, the incidence of AD has remained stable. Multiple independent risk factors for AD were identified and poor postoperative outcomes confirmed. However, many known impediments to wound healing such as recipient chronic steroid use, recipient and donor diabetes, and donor smoking were not identified as risk factors for AD, reinforcing the critical role of technical performance.

Transapical Beating-Heart Mitral Valve Repair With an Expanded Polytetrafluoroethylene Cordal Implantation Device: Initial Clinical Experience.

BACKGROUND: Degenerative mitral valve (MV) disease is a common cause of severe mitral regurgitation (MR) and accounts for the majority of MV operations. Conventional MV surgery requires cardiopulmonary bypass, aortic cross-clamping, cardioplegia, and a thoracotomy or sternotomy and, therefore, is associated with significant disability, risks, and unpredictable rates of MV repair. Transesophageal echocardiography-guided beating-heart MV repair with expanded polytetrafluoroethylene cordal insertion has the potential to significantly reduce surgical morbidity. We report the first-in-human clinical experience with a novel preformed expanded polytetrafluoroethylene knot implantation device (Harpoon TSD-5) designed to treat degenerative MR. METHODS: Through a small left thoracotomy, the device was inserted into the heart and guided by transesophageal echocardiography to the ventricular surface of the prolapsed leaflet. Multiple expanded polytetrafluoroethylene cords were anchored in the leaflet and then adjusted to the correct length to restore MV leaflet coaptation and secured at the epicardium. RESULTS: Eleven patients with posterior leaflet prolapse and severe MR, with mean±SD age of 65±13 years and mean ejection fraction of 69±7%, were treated with 100% procedural success. Immediate postprocedural mean MR grade was trace. At 1 month, the mean MR grade was mild with significant decreases in end-diastolic volume (139 to 107 mL; P=0.03) and left atrial volume (118 to 85 mL; P=0.04). CONCLUSIONS: A novel device used for beating-heart image-guided MV repair demonstrates a significant reduction in MR with favorable left ventricular and left atrial reverse remodeling. This approach has the potential to decrease invasiveness and surgical morbidity. Further follow-up is necessary to assess long-term efficacy. CLINICAL TRIAL REGISTRATION: URL: https://clinicaltrials.gov. Unique identifier: NCT02432196.

General and acute care surgical procedures in patients with left ventricular assist devices.

BACKGROUND: Left ventricular assist devices (LVADs) have become common as a bridge to heart transplant as well as destination therapy. Acute care surgical (ACS) problems in this population are prevalent but remain ill-defined. Therefore, we reviewed our experience with ACS interventions in LVAD patients. METHODS: A total of 173 patients who received HeartMate(®) XVE or HeartMate(®) II (HMII) LVADs between December 2001 and March 2010 were studied. Patient demographics, presentation of ACS problem, operative intervention, co-morbidities, transplantation, complications, and survival were analyzed. RESULTS: A total of 47 (27 %) patients underwent 67 ACS procedures at a median of 38 days after device implant (interquartile range 15-110), with a peri-operative mortality rate of 5 % (N = 3). Demographics, device type, and acuity were comparable between the ACS and non-ACS groups. A total of 21 ACS procedures were performed emergently, eight were urgent, and 38 were elective. Of 29 urgent and emergent procedures, 28 were for abdominal pathology. In eight patients, the cause of the ACS problem was related to LVADs or anticoagulation. Cumulative survival estimates revealed no survival differences if patients underwent ACS procedures (p = 0.17). Among HMII patients, transplantation rates were unaffected by an ACS intervention (p = 0.2). CONCLUSIONS: ACS problems occur frequently in LVAD patients and are not associated with adverse outcomes in HMII patients. The acute care surgeon is an integral member of a comprehensive approach to effective LVAD management.

Pim-1 mediated signaling during the process of cardiac remodeling following myocardial infarction in ovine hearts.

The serine/threonine kinase Pim-1 was recently identified as a cardiomyocyte survival regulator downstream of Akt. The present study aims to examine Pim-1 activity and its association with the post MI remodeling myocardium in a clinically relevant large animal model. Apical myocardial infarction of approximately 25% left ventricular mass was created in an ovine model. Regional post-infarction deformation of the left ventricle was monitored by sonomicrometry and quantified using areal remodeling strain (i.e., areal expansion). Myocardial tissues were harvested at 12weeks from the adjacent and remote regions of the infarct for analysis of Pim-1 mediated survival signaling proteins as well as apoptotic activity. The cDNA coding sequences of two ovine Pim-1 kinase isoforms, 44 and 33kDa, were identified. Both isoforms were detected in heart tissue and the overall Pim-1 expression was found to be tightly controlled at multiple molecular levels. Pim-1 as well as the Pim-1 mediated survival signaling proteins Bcl-2, Bcl-xL, and phospho-Bad (Ser112) were upregulated in the adjacent region at 12weeks post-infarction and their expression correlated positively with the degree of the remodeling, which was accompanied by significant upregulations of the PP2A/BAD mediated apoptotic signaling proteins. However these upregulations were imbalanced, such that p-BAD (Ser112)/BAD decreased in the adjacent region of the infarcted hearts. Apoptotic activity also increased with remodeling strain. Despite an observed intrinsic upregulation of survival proteins, the imbalanced activation of apoptotic pathways resulted in evident apoptosis in the adjacent region. ULTRAMINI-ABSTRACT: Pim-1 mediated survival signaling in myocardial tissues from infarcted ovine hearts was studied. It was shown that the adjacent region of the infarct experienced higher remodeling strain and exhibited increased levels of Pim-1 and related anti-apoptotic proteins. Despite this elevation of survival activity, however, the imbalanced activation of PP2A/BAD mediated apoptotic pathway resulted in evident apoptosis in the adjacent region.

Ex vivo lung evaluation of prearrest heparinization in donation after cardiac death.

OBJECTIVE: To evaluate the effects of prearrest heparin administration on lung quality in a model of donation after cardiac death (DCD), and to assess the potential application of ex vivo lung perfusion (EVLP) in the identification of better grafts from the DCD donor pool. METHODS: Cardiac death was induced by electric shock in 10 pigs. One group received a prearrest heparin dose of 300 units/kg (H group, n = 5) and the other did not (NH group, n = 5). Animals remained at room temperature for 1 hour without ventilation, defining the warm ischemic time. After harvest, the lungs underwent 6 hours of cold ischemia before being evaluated with EVLP for 4 hours. RESULTS: Static compliance 28 ± 3 versus 29 ± 2 (Cstat-cm H2O), pulmonary vascular resistance (PVR) 593 ± 127 versus 495 ± 70 (PVR-dyn·s/cm), and oxygenation 327 ± 32 versus 330 ± 28 (ΔPO2-mm Hg) remained stable from the beginning until the end of EVLP in the H group. In the NH group, Cstat started to decline after the first hour (25 ± 2 vs 21 ± 2), ΔPO2 after hour 2 (265 ± 44 vs 207 ± 44), and PVR started to increase after hour 3 (765 ± 132 vs 916 ± 168). Significant differences between the groups were observed at the end of EVLP (P < 0.001). Parameters of lung quality after EVLP also showed significant differences between the groups: wet weight-to-dry weight ratio (P < 0.001), protein in the bronchial lavage (P < 0.01), Na + K-ATPase activity (P < 0.001), and E-selectin (P < 0.001) in the perfusate. CONCLUSIONS: Prearrest heparin administration improved organ function by preserving endothelial homeostasis. EVLP proved to be a useful platform for assessing DCD lungs, providing reliable means of discriminating injured grafts.

An automated coring and apical connector insertion device facilitates aortic valve bypass (apicoaortic conduit) surgery: preclinical experience in a chronic ovine model.

BACKGROUND AND AIM OF THE STUDY: Aortic valve bypass (AVB, apicoaortic conduit) surgery is an alternative treatment for high-risk patients with aortic stenosis (AS). An automated coring and connector insertion device designed to simplify the apical AVB anastomosis has been developed. The applicator consists of a toroidal shaft-mounted balloon, an integrated circular coring knife, and a stented apical connector supporting a Dacron graft. In this way, apical myocardial coring, connector insertion and core removal may be automated. METHODS: AVB was performed without cardiopulmonary bypass in eight sheep. A conduit containing a porcine valve was anastomosed to the descending aorta using a partial occlusion clamp. The applicator was used to insert the apical connector, and the connector and conduit were joined with a quick-connector. The descending aorta was occluded proximal to the distal anastomosis to simulate AS. Gradients across the conduit were measured after implantation, and one month later at sacrifice. RESULTS: All AVB implants were performed successfully. The median blood loss was 50 ml (IQR: 13- 98 ml). The median connector implantation time was 29 s, and the peak gradients across the conduit early and at 30 days after AVB were 5.2 +/- 2.6 mmHg and 2.7 +/- 1.4 mmHg, respectively. One animal died of hemothorax at 24 h after surgery, but all remaining animals survived and gained weight. Gross and histopathologic assessments demonstrated widely patent conduits and normal brain histology in all animals. CONCLUSION: The applicator facilitated the safe and expeditious performance of AVB surgery. The clinical use of this device will improve the safety and increase the adoption of this beating-heart therapy for AS.

Inferior Vena Cava Filter Placement Through a Venovenous Extracorporeal Membrane Oxygenation Circuit.

We present a technique for performing endovascular procedures by obtaining vascular access directly through a venovenous extracorporeal membrane oxygenation (VV ECMO) circuit. This technique is demonstrated in a lung transplant recipient, supported on VV ECMO, whose course was complicated by an extensive right femoral vein and inferior vena cava deep venous thrombosis. The patient was successfully managed by the placement of an inferior vena cava filter using the VV ECMO circuit as a point of access to the circulatory system before cessation of VV ECMO support and decannulation.

Exosomes isolated from human cardiosphere-derived cells attenuate pressure overload-induced right ventricular dysfunction.

OBJECTIVES: Cardiosphere-derived cell (CDC) transplantation has been shown to attenuate right ventricular (RV) dysfunction in patients with hypoplastic left heart syndrome. However, live cell transplantation requires complex handling protocols that may limit its use. Exosomes are protein and nucleic acid-containing nanovesicles secreted by many cell types, including stem cells, which have been shown to exert a cardioprotective effect comparable with whole cells following myocardial injury. We therefore sought to evaluate 3 human CDC-derived exosome preparations in a juvenile porcine model of acute pressure-induced RV dysfunction. METHODS: Twenty immunocompetent juvenile Yorkshire pigs (7-10 kg) underwent pulmonary arterial banding followed by intramyocardial test agent administration: control (n = 6), XO-1 (n = 4), XO-2 (n = 5), and XO-3 (n = 5). Animals were monitored for 28 days postoperatively with periodic phlebotomy and echocardiography, followed by extensive postmortem gross and histopathologic analysis. RESULTS: All animals survived the banding operation. One died suddenly on postoperative day 1; another was excluded due to nonstandard response to banding. Of the remaining animals, there were no clinical concerns. RV fractional area change was improved in the XO-1 and XO-2 groups relative to controls at postoperative day 28. On histologic analysis, exosome-treated groups exhibited decreased cardiomyocyte hypertrophy with respect to controls. CONCLUSIONS: Human CDC-derived exosome administration was associated with significant preservation of RV systolic function in the setting of acute pressure overload. Such acellular preparations may prove superior to whole cells and may represent a novel therapeutic approach to clinical myocardial injury.

A Minimally Invasive Approach to Left Ventricular Assist Device Insertion Facilitates Subsequent Explant.

A minimally invasive approach to left ventricular assist device (LVAD) insertion may benefit patients at the time of implant, but whether the approach to LVAD insertion influences the outcome of subsequent cardiovascular reoperations is unknown. Here we present the case of a 50-year-old male who underwent LVAD insertion through a minimally invasive approach and subsequently had left ventricular recovery. LVAD explant was performed without the use of any blood products or inotropic support. This case demonstrates that a minimally invasive approach to LVAD insertion may also facilitate subsequent device explant.

A novel adaptor system enables endovascular access through extracorporeal life support circuits.

OBJECTIVE: Extracorporeal life support has traditionally been used as a supportive platform for patients with cardiopulmonary failure. Many of these patients require endovascular access for the performance of diagnostic or therapeutic procedures, and obtaining vascular access in these patients can be problematic. We sought to develop a novel system that allows the extracorporeal life support circuit to serve as an access point to the cardiovascular system. METHODS: By using computer-aided design, modeling, and 3-dimensional printing, a novel adaptor that can be easily inserted and removed from an extracorporeal life support circuit was developed. A mock loop was used to measure flow and pressure at various pump speeds with insertion of guidewires and catheters through the adaptor. The ability of the system to enable performance of endovascular procedures in vivo was then tested in a porcine extracorporeal life support model. RESULTS: By using a small arterial cannula (15F) at 3500 RPM and 3.2 LPM, 15% and 24% decrements in circuit flow were observed when a 0.035" guidewire and 5F angiography catheter, respectively, were passed through the adaptor (P < .001). However, when using a larger arterial cannula (23F) at 3500 RPM and 4.7 LPM, only 3% and 5% decrements in flow were observed (P < .001), respectively, with intermediate changes when using 17F to 21F cannulas. In vivo testing confirmed that this system enables the performance of a variety of endovascular procedures, including left ventriculography, aortic root and coronary angiography, and descending aortography. CONCLUSIONS: This novel system successfully enables endovascular access through an extracorporeal life support circuit. This technology may transform extracorporeal life support from a purely supportive strategy to a platform for endovascular intervention.

The Incidence and Outcomes of Surgical Pulmonary Embolectomy in North America.

BACKGROUND: There has been renewed interest in surgical pulmonary embolectomy (SPE) for the treatment of pulmonary embolism, but the real-world incidence and outcomes of SPE have yet to be well described using a large, granular data set. We examined the modern experience with SPE in North America as reported to the Society of Thoracic Surgery Adult Cardiac Surgery Database (STS ACSD). METHODS: The STS ACSD was queried for all isolated SPE for the treatment of acute pulmonary embolism (2011 to 2015). Groups were stratified based on presentation: no cardiogenic shock (NCS), cardiogenic shock without arrest (CS), and cardiogenic shock with cardiac arrest (CS/CA). Preoperative characteristics, intraoperative variables, postoperative in-hospital complications, and operative mortality were compared. Multivariable logistic regression was performed to identify risk factors for in-hospital mortality. RESULTS: Of the 1,144 centers reporting during the study period, only 310 performed at least 1 SPE (overall mean, 0.42 ± 1.03 cases • year-1 • center-1). A total of 1,075 eligible SPE were identified (NCS = 719, CS = 203, CS/CA = 153). Median age was 57 years (interquartile range, 45 to 67), 54% were male, and preoperative thrombolysis was used in 8%. Overall, operative mortality was 16%, but increased with presenting acuity (NCS = 8%, CS = 23%, CS/CA = 44%, p < 0.001). Independent predictors of operative mortality included age, obesity, cardiogenic shock, preoperative arrest, chronic lung disease, unresponsive neurologic state, and prolonged cardiopulmonary bypass time. CONCLUSIONS: SPE is uncommonly performed in North America, and, in selected patients, it may be associated with favorable outcomes. Nevertheless, significant mortality exists, and attention to patient presentation and other risk factors may help distinguish patients appropriate for SPE.

Outcomes after surgical pulmonary embolectomy for acute submassive and massive pulmonary embolism: A single-center experience.

OBJECTIVES: Ideal treatment strategies for submassive and massive pulmonary embolism remain unclear. Recent reports of surgical pulmonary embolectomy have demonstrated improved outcomes, but surgical technique and postoperative outcomes continue to be refined. The aim of this study is to describe in-hospital survival and right ventricular function after surgical pulmonary embolectomy for submassive and massive pulmonary embolism with excessive predicted mortality (≥5%). METHODS: All patients undergoing surgical pulmonary embolectomy (2011-2015) were retrospectively reviewed. Patients with pulmonary embolism were stratified as submassive, massive without arrest, and massive with arrest. Submassive was defined as normotensive with right ventricular dysfunction. Massive was defined as prolonged hypotension due to the pulmonary embolism. Preoperative demographics, intraoperative variables, and postoperative outcomes were compared. RESULTS: A total of 55 patients were identified: 28 as submassive, 18 as massive without arrest, and 9 as massive with arrest. All patients had a right ventricle/left ventricle ratio greater than 1.0. Right ventricular dysfunction decreased from moderate preoperatively to none before discharge (P < .001). In-hospital and 1-year survival were 93% and 91%, respectively, with 100% survival in the submassive group. No patients developed renal failure requiring hemodialysis at discharge or had a postoperative stroke. CONCLUSIONS: In this single institution experience, surgical pulmonary embolectomy is a safe and effective therapy to treat patients with a submassive or massive pulmonary embolism. Although survival in this study is higher than previously reported for patients treated with medical therapy alone, a prospective trial comparing surgical therapy with medical therapy is necessary to further elucidate the role of surgical pulmonary embolectomy in the treatment of pulmonary embolism.

Regenerative medicine therapy for single ventricle congenital heart disease.

One of the most complex forms of congenital heart disease (CHD) involving single ventricle physiology is hypoplastic left heart syndrome (HLHS), characterized by underdevelopment of the left ventricle (LV), mitral and aortic valves, and narrowing of the ascending aorta. The underdeveloped LV is incapable of providing long-term systemic flow, and if left untreated, the condition is fatal. Current treatment for this condition consists of three consecutive staged palliative operations: the first is conducted within the first few weeks of birth, the second between 4 to 6 months, and the third and final surgery within the first 4 years. At the conclusion of the third surgery, systemic perfusion is provided by the right ventricle (RV), and deoxygenated blood flows passively to the pulmonary vasculature. Despite these palliative interventions, the RV, which is ill suited to provide long-term systemic perfusion, is prone to eventual failure. In the absence of satisfying curative treatments, stem cell therapy may represent one innovative approach to the management of RV dysfunction in HLHS patients. Several stem cell populations from different tissues (cardiac and non-cardiac), different age groups (adult- vs. neonate-derived), and different donors (autologous vs. allogeneic), are under active investigation. Preclinical trials in small and large animal models have elucidated several mechanisms by which these stem cells affect the injured myocardium, and are driving the shift from a paradigm based upon cellular engraftment and differentiation to one based primarily on paracrine effects. Recent studies have comprehensively evaluated the individual components of the stem cells' secretomes, shedding new light on the intracellular and extracellular pathways at the center of their therapeutic effects. This research has laid the groundwork for clinical application, and there are now several trials of stem cell therapies in pediatric populations that will provide important insights into the value of this therapeutic strategy in the management of HLHS and other forms of CHD. This article reviews the many stem cell types applied to CHD, their preclinical investigation and the mechanisms by which they might affect RV dysfunction in HLHS patients, and finally, the completed and ongoing clinical trials of stem cell therapy in patients with CHD.

Triage and optimization: A new paradigm in the treatment of massive pulmonary embolism.

BACKGROUND: Massive pulmonary embolism (PE) remains a highly fatal condition. Although venoarterial extracorporeal membrane oxygenation (VA-ECMO) and surgical pulmonary embolectomy in the management of massive PE have been reported previously, the outcomes remain less than ideal. We hypothesized that the institution of a protocolized approach of triage and optimization using VA-ECMO would result in improved outcomes compared with historical surgical management. METHODS: All patients with a massive PE referred to the cardiac surgery service between 2010 and 2017 were retrospectively reviewed. Patients were stratified by treatment strategy: historical control versus the protocolized approach. In the historical control group, the primary intervention was surgical pulmonary embolectomy. In the protocol approach group, patients were treated based on an algorithmic approach using VA-ECMO. The primary outcome was 1-year survival. RESULTS: A total of 56 patients (control, n = 27; protocol, n = 29) were identified. All 27 patients in the historical control group underwent surgical pulmonary embolectomy, whereas 2 of 29 patients in the protocol approach group were deemed appropriate for direct surgical pulmonary embolectomy. The remaining 27 patients were placed on VA-ECMO. In the protocol approach group, 15 of 29 patients were treated with anticoagulation alone and 14 patients ultimately required surgical pulmonary embolectomy. One-year survival was significantly lower in the historical control group compared with the protocol approach group (73% vs 96%; P = .02), with no deaths occurring after surgical pulmonary embolectomy in the protocol approach group. CONCLUSIONS: A protocolized strategy involving the aggressive institution of VA-ECMO appears to be an effective method to triage and optimize patients with massive PE to recovery or intervention. Implementation of this strategy rather than an aggressive surgical approach may reduce the mortality associated with massive PE.

The Optimal Procedure for Retransplantation After Single Lung Transplantation.

BACKGROUND: Retransplantation has emerged as a therapeutic option for patients experiencing respiratory failure after single lung transplantation. However, outcomes associated with the surgical option (ipsilateral, contralateral, or bilateral lung retransplantation) has not been well evaluated. METHODS: The Organ Procurement and Transplantation Network database (1994 to 2012) was queried for all lung transplant procedures performed after an initial single lung transplantation. Donor and recipient demographics, before and after transplant characteristics, and outcomes were stratified by retransplant procedural choice and by interval between transplants. Risk factors for mortality were evaluated by Cox proportional hazards regression analysis. RESULTS: Of 325 prior single lung transplant recipients, 50 underwent ipsilateral, 175 contralateral, and 100 bilateral lung retransplantation. The number of retransplant procedures performed per year increased from 3 in 1994 to 31 in 2012, with an increasing proportion of contralateral retransplantation and declining proportions of ipsilateral and bilateral retransplantation. Survival was significantly better in the contralateral and bilateral retransplant groups than in the ipsilateral retransplant group at 30 days (94% and 89% versus 80%), 1 year (72% and 67% versus 50%), and 5 years (41% and 42% versus 20%). Ipsilateral retransplantation (hazard ratio 1.48; p = 0.042), mechanical ventilation before retransplant (hazard ratio 2.39; p < 0.001), and retransplantation performed in the first half of the study period (hazard ratio 1.45; p = 0.027) were associated with increased mortality. CONCLUSIONS: After an initial single lung transplant, both the incidence of retransplantation and postoperative survival have increased with time. Although ipsilateral lung retransplantation may be the best available alternative in particular circumstances, this analysis suggests that contralateral or bilateral lung retransplantation may be preferable in patients for whom those options are medically sensible.

Venovenous Versus Venoarterial Extracorporeal Membrane Oxygenation for Adult Patients With Acute Respiratory Distress Syndrome Requiring Precannulation Hemodynamic Support: A Review of the ELSO Registry.

BACKGROUND: In addition to severe hypoxia and hypercapnia, acute respiratory distress syndrome (ARDS) can present with substantial hemodynamic compromise, requiring inotropic or vasopressor support or both. Either venovenous (VV) or venoarterial (VA) extracorporeal membrane oxygenation (ECMO) can be offered in this situation. However, a contemporary comparison of these two cannulation strategies has yet to be well described. METHODS: The Extracorporeal Life Support Organization Registry was reviewed for all cases of adult ARDS in patients that required inotropic agents or vasopressors or both before ECMO initiation (2009 to 2013). Pre-ECMO clinical data, ECMO variables, and outcomes were compared, based on initial cannulation strategy (VV or VA ECMO). RESULTS: Of 717 ECMO runs, there were 591 VV ECMO and 126 VA ECMO cases. Over the study period, the proportion of VA ECMO cases decreased from 20% (n = 37 of 184, 2009 to 2010) to 19% (n = 59 of 312, 2011 to 2012) to 14% (n = 30 of 221, 2013). Conversion from VV ECMO to VA ECMO was 4%. VV ECMO was associated with less gastrointestinal bleeding and hemolysis, but overall rates of bleeding, stroke, and renal failure were similar. Survival to discharge was 58% for VV ECMO in contrast to 43% for VA ECMO (p = 0.002). Multivariable regression analysis revealed VV ECMO to be an independent predictor of survival to discharge relative to VA ECMO. CONCLUSIONS: In this review of ARDS patients requiring pre-ECMO hemodynamic support, VV ECMO was not associated with worse survival or complication rates compared with VA ECMO. These data suggest that, in appropriately selected patients, it may be reasonable to initially institute VV ECMO support, reserving VA ECMO for conversion for refractory hypotension.