The Impact of Donor Smoking on Primary Graft Dysfunction and Mortality after Lung Transplantation.

Rationale: Primary graft dysfunction (PGD) is the leading cause of early morbidity and mortality after lung transplantation. Prior studies implicated proxy-defined donor smoking as a risk factor for PGD and mortality. Objectives: We aimed to more accurately assess the impact of donor smoke exposure on PGD and mortality using quantitative smoke exposure biomarkers. Methods: We performed a multicenter prospective cohort study of lung transplant recipients enrolled in the Lung Transplant Outcomes Group cohort between 2012 and 2018. PGD was defined as grade 3 at 48 or 72 hours after lung reperfusion. Donor smoking was defined using accepted thresholds of urinary biomarkers of nicotine exposure (cotinine) and tobacco-specific nitrosamine (4-[methylnitrosamino]-1-[3-pyridyl]-1-butanol [NNAL]) in addition to clinical history. The donor smoking-PGD association was assessed using logistic regression, and survival analysis was performed using inverse probability of exposure weighting according to smoking category. Measurements and Main Results: Active donor smoking prevalence varied by definition, with 34-43% based on urinary cotinine, 28% by urinary NNAL, and 37% by clinical documentation. The standardized risk of PGD associated with active donor smoking was higher across all definitions, with an absolute risk increase of 11.5% (95% confidence interval [CI], 3.8% to 19.2%) by urinary cotinine, 5.7% (95% CI, -3.4% to 14.9%) by urinary NNAL, and 6.5% (95% CI, -2.8% to 15.8%) defined clinically. Donor smoking was not associated with differential post-lung transplant survival using any definition. Conclusions: Donor smoking associates with a modest increase in PGD risk but not with increased recipient mortality. Use of lungs from smokers is likely safe and may increase lung donor availability. Clinical trial registered with www.clinicaltrials.gov (NCT00552357).

Multicenter evaluation of left ventricular assist device implantation with or without ECMO bridge in cardiogenic shock.

BACKGROUND: The efficacy of extracorporeal membrane oxygenation (ECMO) as a bridge to left ventricular assist device (LVAD) remains unclear, and recipients of the more contemporary HeartMate 3 (HM3) LVAD are not well represented in previous studies. We therefore undertook a multicenter, retrospective study of this population. METHODS AND RESULTS: INTERMACS 1 LVAD recipients from five U.S. centers were included. In-hospital and one-year outcomes were recorded. The primary outcome was the overall mortality hazard comparing ECMO versus non-ECMO patients by propensity-weighted survival analysis. Secondary outcomes included survival by LVAD type, as well as postoperative and one-year outcomes. One hundred and twenty-seven patients were included; 24 received ECMO as a bridge to LVAD. Mortality was higher in patients bridged with ECMO in the primary analysis (HR 3.22 [95%CI 1.06-9.77], p = 0.039). Right ventricular assist device was more common in the ECMO group (ECMO: 54.2% vs non-ECMO: 11.7%, p < 0.001). Ischemic stroke was higher at one year in the ECMO group (ECMO: 25.0% vs non-ECMO: 4.9%, p = 0.006). Among the study cohort, one-year mortality was lower in HM3 than in HeartMate II (HMII) or HeartWare HVAD (10.5% vs 46.9% vs 31.6%, respectively; p < 0.001) recipients. Pump thrombosis at one year was lower in HM3 than in HMII or HVAD (1.8% vs 16.1% vs 16.2%, respectively; p = 0.026) recipients. CONCLUSIONS: Higher mortality was observed with ECMO as a bridge to LVAD, likely due to higher acuity illness, yet acceptable one-year survival was seen compared with historical rates. The receipt of the HM3 was associated with improved survival compared with older generation devices.

Extracorporeal Carbon Dioxide Removal to De-escalate Venovenous Extracorporeal Membrane Oxygenation in Severe COVID-19 Acute Respiratory Distress Syndrome.

OBJECTIVES: In a subset of patients with COVID-19 acute respiratory distress syndrome (ARDS), there is a need for extracorporeal membrane oxygenation (ECMO) for pulmonary support. The primary extracorporeal support tool for severe COVID-19 ARDS is venovenous (VV) ECMO; however, after hypoxemic respiratory failure resolves, many patients experience refractory residual hypercarbic respiratory failure. Extracorporeal carbon dioxide removal (ECCO2R) for isolated hypercarbic type II respiratory failure can be used in select cases to deescalate patients from VV ECMO while the lung recovers the ability to exchange CO2. The objective of this study was to describe the authors' experience in using ECCO2R as a bridge from VV ECMO. DESIGN: Hemolung Respiratory Assist System (RAS) is a commercially available (ECCO2R) device, and the United States Food and Drug Administration accelerated its use under its Emergency Use Authorization for the treatment of refractory hypercarbic respiratory failure in COVID-19-induced ARDS. This created an environment in which selected and targeted mechanical circulatory support therapy for refractory hypercarbic respiratory failure could be addressed. This retrospective study describes the application of Hemolung RAS as a VV ECMO deescalation platform to treat refractory hypercarbic respiratory failure after the resolution of hypoxemic COVID-19 ARDS. SETTING: A quaternary-care academic medical center, single institution. PARTICIPANTS: Patients with refractory hypercarbic respiratory failure after COVID-19 ARDS who were previously supported with VV ECMO. MEASUREMENTS AND MAIN RESULTS: Twenty-one patients were placed on ECCO2R after VV ECMO for COVID-19 ARDS. Seventeen patients successfully were transitioned to ECCO2R and then decannulated; 3 patients required reescalation to VV ECMO secondary to hypercapnic respiratory failure, and 1 patient died while on ECCO2R. Five (23.8%) of the 21 patients were transitioned off of VV ECMO to ECCO2R, with a compliance of <20 (mL/cmH2O). Of these patients, 3 with low compliance were reescalated to VV ECMO. CONCLUSIONS: Extracorporeal carbon dioxide removal can be used to continue supportive methods for patients with refractory type 2 hypercarbic respiratory failure after COVID-19 ARDS for patients previously on VV ECMO. Patients with low compliance have a higher rate of reescalation to VV ECMO.

Infectious complications associated with bronchial anastomotic dehiscence in lung transplant recipients.

INTRODUCTION: Bronchial anastomotic dehiscence (AD) is an uncommon complication following lung transplantation that carries significant morbidity and mortality. The objective of this study was to characterize fungal and bacterial infections in ADs, including whether infections following AD were associated with progression to bronchial stenosis. METHODS: This was a single-center study of 615 lung transplant recipients between 6/1/2015 and 12/31/2021. Airway complications were defined according to ISHLT consensus guidelines. RESULTS: 22 of the 615 recipients (3.6%) developed an AD. Bronchial ischemia or necrosis was common prior to dehiscence (68.1%). Fourteen (63.6%) recipients had bacterial airway infections, most commonly with Gram-negative rods, prior to dehiscence. Thirteen (59.1%) recipients had an associated pleural infection, most commonly with Candida species (30.8%). Post-dehiscence Aspergillus species were isolated in 4 recipients, 3 of which were de novo infections. Eleven had bacterial infections prior to dehiscence resolution, most commonly with Pseudomonas aeruginosa. Eleven recipients developed airway stenosis requiring dilation and/or stenting. Development of secondary infection prior to AD resolution was not associated with progression to stenosis (OR = .41, 95% CI = .05-3.30, p = .41). CONCLUSIONS: Gram-negative bacterial infections are common before and after AD. Pleural infection should be suspected in most cases. Infections prior to healing were not associated with subsequent development of airway stenosis.

Quality and readability of online patient information on the left ventricular assist device.

BACKGROUND: As patients seek online health information to supplement their medical decision-making, the aim of this study is to assess the quality and readability of internet information on the left ventricular assist device (LVAD). METHODS: Three online search engines (Google, Bing, and Yahoo) were searched for "LVAD" and "Left ventricular assist device." Included websites were classified as academic, foundation/advocacy, hospital-affiliated, commercial, or unspecified. The quality of information was assessed using the JAMA benchmark criteria (0-4), DISCERN tool (16-80), and the presence of Health On the Net code (HONcode) accreditation. Readability was assessed using the Flesch Reading Ease score. RESULTS: A total of 38 unique websites were included. The average JAMA and DISCERN scores of all websites were 0.82 ± 1.11 and 52.45 ± 13.51, respectively. Academic sites had a significantly lower JAMA mean score than commercial (p < 0.001) and unspecified (p < 0.001) websites, as well as a significantly lower DISCERN, mean score than commercial sites (p = 0.002). HONcode certification was present in 6 (15%) websites analyzed, which had significantly higher JAMA (p < 0.001) and DISCERN (p < 0.016) mean scores than sites without HONcode certification. Readability was fairly difficult and at the level of high school students. CONCLUSIONS: The quality of online information on the LVAD is variable, and overall readability exceeds the recommended level for the public. Patients accessing online information on the LVAD should be referred to sites with HONcode accreditation. Academic institutions must provide higher quality online patient literature on LVADs.

Subacute groin complications related to ECMO cannulation are associated with longer hospitalizations.

Subacute groin complications associated with extracorporeal membrane oxygenation (ECMO) cannulation are well recognized, yet their effects on clinical outcomes remain unknown. This single-center, retrospective study reviewed all patients receiving venoarterial ECMO from 01/2017 to 02/2020. Cohorts analyzed included transplanted patients (TPs) and non-transplanted patients (N-TPs) who did or did not develop ECMO-related subacute groin complications. Standard descriptive statistics were used for comparisons. Logistic regressions identified associated risk factors. Overall, 82/367 (22.3%) ECMO patients developed subacute groin complications, including 25/82 (30.5%) seromas/lymphoceles, 32/82 (39.0%) hematomas, 18/82 (22.0%) infections, and 7/82 (8.5%) non-specified collections. Of these, 20/82 (24.4%) underwent surgical interventions, most of which were muscle flaps (14/20, 70.0%). TPs had a higher incidence of subacute groin complications than N-TPs (14/28, 50.0% vs. 68/339, 20.1%, P = 0.001). Seromas/lymphoceles more often developed in TPs than N-TPs (10/14, 71.4% vs. 15/68, 22.1%, P = 0.001). Most patients with subacute groin complications survived to discharge (60/68, 88.2%). N-TPs who developed subacute groin complications had longer post-ECMO lengths of stay than those who did not (34 days, IQR 16-53 days vs. 17 days, IQR 8-34 days, P < 0.001). Post-ECMO length of stay was also longer among patients who underwent related surgical interventions compared to those who did not (50 days, IQR 35-67 days vs. 29 days, IQR 16-49 days, P = 0.007). Transplantation was the strongest risk factor for developing subacute groin complications (OR 3.91, CI95% 1.52-10.04, P = 0.005). Subacute groin complications and related surgical interventions are common after ECMO cannulation and are associated with longer hospital stays. When surgical management is warranted, muscle flaps may reduce lengths of stay compared to other surgical interventions.

Extracorporeal Life Support for Respiratory Failure in Patients With Electronic Cigarette or Vaping Product Use-Associated Lung Injury.

OBJECTIVES: Electronic cigarette or vaping product use-associated lung injury is a clinical entity that can lead to respiratory failure and death. Despite the severity of electronic cigarette or vaping product use-associated lung injury, the role of extracorporeal life support in its management remains unclear. Our objective was to describe the clinical characteristics and outcomes of patients with electronic cigarette or vaping product use-associated lung injury who received extracorporeal life support. DESIGN: We performed a retrospective review of records of electronic cigarette or vaping product use-associated lung injury patients who received extracorporeal life support. Standardized data were collected via direct contact with extracorporeal life support centers. Data regarding presentation, ventilatory management, extracorporeal life support details, and outcome were analyzed. SETTING: This was a multi-institutional, international case series with patients from 10 different institutions in three different countries. PATIENTS: Patients who met criteria for confirmed electronic cigarette or vaping product use-associated lung injury (based on previously reported diagnostic criteria) and were placed on extracorporeal life support were included. Patients were identified via literature review and by direct contact with extracorporeal life support centers. MEASUREMENTS AND MAIN RESULTS: Data were collected for 14 patients ranging from 16 to 45 years old. All had confirmed vape use within 3 months of presentation. Nicotine was the most commonly used vaping product. All patients had respiratory symptoms and radiographic evidence of bilateral pulmonary opacities. IV antibiotics and corticosteroids were universally initiated. Patients were intubated for 1.9 days (range, 0-6) prior to extracorporeal life support initiation. Poor oxygenation and ventilation were the most common indications for extracorporeal life support. Five patients showed evidence of ventricular dysfunction on echocardiography. Thirteen patients (93%) were placed on venovenous extracorporeal life support, and one patient required multiple rounds of extracorporeal life support. Total extracorporeal life support duration ranged from 2 to 37 days. Thirteen patients survived to hospital discharge; one patient died of septic shock. CONCLUSIONS: Electronic cigarette or vaping product use-associated lung injury can cause refractory respiratory failure and hypoxemia. These data suggest that venovenous extracorporeal life support can be an effective treatment option for profound, refractory respiratory failure secondary to electronic cigarette or vaping product use-associated lung injury.

Pulmonary vascular inflammation with fatal coronavirus disease 2019 (COVID-19): possible role for the NLRP3 inflammasome.

BACKGROUND: Pulmonary hyperinflammation is a key event with SARS-CoV-2 infection. Acute respiratory distress syndrome (ARDS) that often accompanies COVID-19 appears to have worse outcomes than ARDS from other causes. To date, numerous lung histological studies in cases of COVID-19 have shown extensive inflammation and injury, but the extent to which these are a COVID-19 specific, or are an ARDS and/or mechanical ventilation (MV) related phenomenon is not clear. Furthermore, while lung hyperinflammation with ARDS (COVID-19 or from other causes) has been well studied, there is scarce documentation of vascular inflammation in COVID-19 lungs. METHODS: Lung sections from 8 COVID-19 affected and 11 non-COVID-19 subjects, of which 8 were acute respiratory disease syndrome (ARDS) affected (non-COVID-19 ARDS) and 3 were from subjects with non-respiratory diseases (non-COVID-19 non-ARDS) were H&E stained to ascertain histopathological features. Inflammation along the vessel wall was also monitored by expression of NLRP3 and caspase 1. RESULTS: In lungs from COVID-19 affected subjects, vascular changes in the form of microthrombi in small vessels, arterial thrombosis, and organization were extensive as compared to lungs from non-COVID-19 (i.e., non-COVID-19 ARDS and non-COVID-19 non-ARDS) affected subjects. The expression of NLRP3 pathway components was higher in lungs from COVID-19 ARDS subjects as compared to non-COVID-19 non-ARDS cases. No differences were observed between COVID-19 ARDS and non-COVID-19 ARDS lungs. CONCLUSION: Vascular changes as well as NLRP3 inflammasome pathway activation were not different between COVID-19 and non-COVID-19 ARDS suggesting that these responses are not a COVID-19 specific phenomenon and are possibly more related to respiratory distress and associated strategies (such as MV) for treatment.

How Should ECMO Be Used Under Conditions of Severe Scarcity? A Population Study of Public Perception.

OBJECTIVE: To assess societal preferences regarding allocation of extracorporeal membrane oxygenation (ECMO) as a rescue option for select patients with coronavirus disease 2019 (COVID-19). DESIGN: Cross-sectional survey of a nationally representative sample. SETTING: Amazon Mechanical Turk platform. PARTICIPANTS: In total, responses from 1,041 members of Amazon Mechanical Turk crowd-sourcing platform were included. Participants were 37.9 ± 12.6 years old, generally white (65%), and college-educated (66.1%). Many reported working in a healthcare setting (22.5%) and having a friend or family member who was admitted to the hospital (43.8%) or died from COVID-19 (29.9%). MEASUREMENTS AND MAIN RESULTS: Although most reported an unwillingness to stay on ECMO for >one week without signs of recovery, participants were highly supportive of ECMO utilization as a life-preserving technique on a policy level. The majority (96.7%) advocated for continued use of ECMO to treat COVID patients during periods of resource scarcity but would prioritize those with highest likelihood of recovery (50%) followed by those who were sickest regardless of survival chances (31.7%). Patients >40 years old were more likely to prefer distributing ECMO on a first-come first-served basis (21.5% v 13.3%, p < 0.05). CONCLUSION: Even though participants expressed hesitation regarding ECMO in personal circumstances, they were uniformly in support of using ECMO to treat COVID patients at a policy level for others who might need it, even in the setting of severe scarcity.

First-in-man successful use of the SPECTRUM percutaneous dual-stage right ventricle and right atrium to pulmonary artery ventricular assist device.

BACKGROUND: Over the past decade, several minimally invasive mechanical support devices have been introduced into clinical practice to support the right ventricle (RV). Percutaneous cannulas are easy to insert, minimally invasive, and treat acute RV failure rapidly. In December 2021, the Food and Drug Administration approved a new 31 French dual lumen single cannula for use as a right ventricular assist device. AIMS: Descirbe the use of the new dual lumen percutaneous right ventricular assist device (RVAD) cannula. MATERIAL AND METHODS: Deployment of the RVAD can be done surgically or percutaneously. This cannula, manufactured by Spectrum, is dual staged. It has inflow ports positioned both in the right atrium (RA) as well as the RV for maximal drainage of the right heart. The distal end of the cannula which includes the outflow port is positioned in the pulmonary artery (PA). RESULTS: Deployment of the Spectrum RVAD can be done percutaneously with transesophageal and flouroscopy guidence. Cannulation requires requisite wire skills in order to navigate into the main pulmonary artery. Utilization of this cannula can be done in acute RV failure secondary to ischemia, post cardiotomy shock, acute respiratory failure or other causes of isolated RV failure. DISCUSSION: The dual stage drainage design optimizes venous drainage as well as limits suck-down events. Theoretically, direct RV decompression also decreases RV dilation and wall tension, and facilitates improved transmural pressure gradient to reduce RV strain. CONCLUSION: Here we describe the first-in-man successful use of the dual-stage RA and RV to PA Spectrum cannula in a patient with severe COVID acute respiratory distress syndrome and acute right ventricular failure, bridged to recovery.

Managing connective tissue disease: how to select and facilitate successful transplantation.

PURPOSE OF REVIEW: Lung transplant (LTx) evaluation and selection of candidates with connective tissue disease (CTD) remains controversial and varies between centers, and the optimal candidate selection is still controversial. RECENT FINDINGS: Recent United States and European publications have reported reasonable short-term and long-term LTx outcomes in patients with CTD to other lung fibrosis patients without CTD. This article discusses the recently published International Society for Heart and Lung Transplantation (ISHLT) consensus document recommendations to evaluate and select CTD candidates, the importance of early referral, posttransplant management, and the involvement of a multidisciplinary team. SUMMARY: Future standardized practices among centers adapting the 2021 ISHLT consensus recommendations to evaluate and select CTD candidates will allow risk stratification, determine the best candidates, and facilitate the most successful long-term LTx outcomes.

Venoarterial Extracorporeal Membrane Oxygenation for Postcardiotomy Shock-Analysis of the Extracorporeal Life Support Organization Registry.

OBJECTIVES: Refractory postcardiotomy cardiogenic shock complicating cardiac surgery yields nearly 100% mortality when untreated. Use of venoarterial extracorporeal membrane oxygenation for postcardiotomy cardiogenic shock has increased worldwide recently. The aim of the current analysis was to outline the trends in use, changing patient profiles, and in-hospital outcomes including complications in patients undergoing venoarterial extracorporeal membrane oxygenation for postcardiotomy cardiogenic shock. DESIGN: Analysis of extracorporeal life support organization registry from January 2010 to December 2018. SETTING: Multicenter worldwide registry. PATIENTS: Seven-thousand one-hundred eighty-five patients supported with venoarterial extracorporeal membrane oxygenation for postcardiotomy cardiogenic shock. INTERVENTIONS: Venoarterial extracorporeal membrane oxygenation. MEASUREMENTS AND MAIN RESULTS: Hospital death, weaning from extracorporeal membrane oxygenation, hospital complications. Mortality predictors were assessed by multivariable logistic regression. Propensity score matching was performed for comparison of peripheral and central cannulation for extracorporeal membrane oxygenation. A significant trend toward more extracorporeal membrane oxygenation use in recent years (coefficient, 0.009; p < 0.001) was found. Mean age was 56.3 ± 14.9 years and significantly increased over time (coefficient, 0.513; p < 0.001). Most commonly, venoarterial extracorporeal membrane oxygenation was instituted after coronary artery bypass surgery (26.8%) and valvular surgery (25.6%), followed by heart transplantation (20.7%). Overall, successful extracorporeal membrane oxygenation weaning was possible in 4,520 cases (56.4%), and survival to hospital discharge was achieved in 41.7% of cases. In-hospital mortality rates remained constant over time (coefficient, -8.775; p = 0.682), whereas complication rates were significantly reduced (coefficient, -0.009; p = 0.003). Higher mortality was observed after coronary artery bypass surgery (65.4%), combined coronary artery bypass surgery with valve (68.4%), and aortic (69.6%) procedures than other indications. Lower mortality rates were observed in heart transplantation recipients (46.0%). Age (p < 0.001), central cannulation (p < 0.001), and occurrence of complications while on extracorporeal membrane oxygenation were independently associated with poorer prognosis. CONCLUSIONS: The analysis confirmed increased use of venoarterial extracorporeal membrane oxygenation for postcardiotomy cardiogenic shock. Mortality rates remained relatively constant over time despite a decrease in complications, in the setting of supporting older patients.

Catheter ablation of atrial arrhythmias following lung transplant: Electrophysiological findings and outcomes.

INTRODUCTION: Data on the mechanisms of atrial arrhythmias (AAs) and outcomes of catheter ablation (CA) in lung transplantation (LT) patients are insufficient. We evaluated the electrophysiologic features and outcomes of CA of AAs in LT patients. METHODS AND RESULTS: We conducted a retrospective study of all the LT patients who underwent CA for AAs at our institution between 2004 and 2019. A total of 15 patients (43% males, age: 61 ± 10 years) with a history of LT (60% bilateral and 40% unilateral) were identified. All patients had documented organized AA on surface electrocardiogram and seven patients also had atrial fibrillation (AF; 47% with >1 clinical arrhythmia). At electrophysiological study, 19 organized AAs were documented (48% focal and 52% macro-re-entrant). Focal atrial tachycardias/flutters were targeted along the pulmonary vein (PV) anastomotic site at the left inferior PV (n = 2), ridge and carina of the left superior PV (n = 2), left atrium (LA) posterior wall (n = 3), LA roof (n = 1), and tricuspid annulus (n = 1). Macro-re-entrant AAs included cavotricuspid isthmus-dependent flutter (n = 2), incisional LA flutter (n = 4), LA roof-dependent flutter (n = 1), and mitral annular flutter (n = 3). In patients with LA mapping (n = 13), PV reconnection on the side of the LT was found in six patients (40%, all with clinically documented AF), with a mean of 2.1 ± 0.9 PVs reconnected per patient. Patients with AF underwent successful PV isolation. After a median follow-up of 19 months (range: 6-86 months), 75% of patients remained free from recurrent AAs. No procedural major complications occurred. CONCLUSION: In patients with prior LT, recurrent AAs are typically associated with substrate surrounding the surgical anastomotic lines and/or chronically reconnected PVs. CA of AAs in this population is safe and effective to achieve long-term arrhythmia control.

Lung transplantation outcomes after crossing low-level donor specific antibodies without planned augmented immunosuppression.

It is unknown whether some donor specific antibodies (DSA) can be crossed at the time of lung transplant without desensitization or augmented induction immunosuppression. This study assessed whether crossing low-level pre-transplant DSA (defined as mean fluorescence intensity [MFI] 1000-6000) without augmented immunosuppression is associated with worse retransplant-free or chronic lung allograft dysfunction (CLAD)-free survival. Of the 458 included recipients, low-level pre-transplant DSA was crossed in 39 (8.6%) patients. The median follow-up time was 2.2 years. There were 15 (38.5%) patients with Class I DSA and 24 (61.5%) with Class II DSA. There was no difference in adjusted overall retransplant-free survival between recipients where pre-transplant DSA was and was not crossed (HR: .98 [95% CI = .49-1.99], P = .96). There was also no difference in CLAD-free survival (HR: .71 [95% CI = .38-1.33], P = .28). There was no difference in Grade 3 PGD at 72 h (OR: 1.13 [95% CI = .52-2.48], P = .75) or definite or probable AMR (HR: 2.22 [95% CI = .64-7.61], P = .21). Lung transplantation in the presence of low-level DSA without planned augmented immunosuppression is not associated with worse overall or CLAD-free survival among recipients with intermediate-term follow-up.

Coronary Artery Bypass Grafting in Cardiogenic Shock: Decision-Making, Management Options, and Outcomes.

Coronary artery bypass grafting is a highly efficacious mode of myocardial revascularization that reduces mortality from ischemic heart disease. The patient presenting after acute myocardial infarction in cardiogenic shock presents a unique challenge. Early revascularization is proven to reduce mortality, but many questions remain, including the optimal mode and extent of revascularization, the role of mechanical circulatory support, and which patients are candidates for surgical intervention. Unprecedented attention to the outcomes of cardiac surgery means decisions about the management of the acute myocardial infarction in cardiogenic shock patients are influenced by risk aversion. The authors here review this topic to arm the reader with a comprehensive understanding of the literature to better guide surgical decision-making and perioperative management.

Severe Impairment of Microcirculatory Perfused Vessel Density Is Associated With Postoperative Lactate and Acute Organ Injury After Cardiac Surgery.

OBJECTIVE: Resuscitation after cardiac surgery needs to address multiple pathophysiological processes that are associated with significant morbidity and mortality. Functional microcirculatory derangements despite normal systemic hemodynamics have been previously described but must be tied to clinical outcomes. The authors hypothesized that microcirculatory dysfunction after cardiac surgery would include impaired capillary blood flow and impaired diffusive capacity and that subjects with the lowest quartile of perfused vessel density would have an increased postoperative lactate level and acute organ injury scores. DESIGN: Prospective, observational study. SETTING: A single, tertiary university cardiovascular surgical intensive care unit. PARTICIPANTS: 25 adults undergoing elective cardiac surgery requiring cardiopulmonary bypass. INTERVENTION: Sublingual microcirculation was imaged using incident dark field microscopy before and 2 to 4 hours after surgery in the intensive care unit. MEASUREMENTS AND MAIN RESULTS: Compared with baseline measurements, postoperative vessel-by-vessel microvascular flow index (2.9 [2.8-2.9] v 2.5 [2.4-2.7], p < 0.0001) and perfused vessel density were significantly impaired (20.7 [19.3-22.9] v 16.3 [12.8-17.9], p < 0.0001). The lowest quartile of perfused vessel density (<12.8 mm/mm2) was associated with a significantly increased postoperative lactate level (6.0 ± 2.9 v 1.8 ± 1.2, p < 0.05), peak lactate level (7.6 ± 2.8 v 2.8 ± 1.5, p = 0.03), and sequential organ failure assessment (SOFA) score at 24 and 48 hours. CONCLUSION: In patients undergoing cardiac surgery, there was a significant decrease in postoperative microcirculatory convective blood flow and diffusive capacity during early postoperative resuscitation. Severely impaired perfused vessel density, represented by the lowest quartile of distribution, is significantly related to hyperlactatemia and early organ injury.

The Surgeon's Role in Cardiogenic Shock.

PURPOSE OF REVIEW: Cardiogenic shock represents a very challenging patient population due to the undifferentiated pathologies presenting as cardiogenic shock, difficult decision-making, prognostication, and ever-expanding support options. The role of cardiac surgeons on this team is evolving. RECENT FINDINGS: The implementation of a shock team is associated with improved outcomes in patients with cardiogenic shock. Early deployment of mechanical circulatory support devices may allow an opportunity to rescue these patients. Cardiothoracic surgeons are a critical component of the shock team who can deploy timely mechanical support and surgical intervention in selected patients for optimal outcomes.

Relationship of intraoperative perfusion parameters to the need for immediate extracorporeal support following heart transplantation.

PURPOSE: We sought to assess the relationship of intraoperative perfusion parameters while on cardiopulmonary bypass, including oxygen delivery (DO2), to the need for ECMO following orthotopic heart transplantation (OHT). METHODS: We included all adult (>18 years old) OHTs performed at our institution since implementation of an electronic perfusion record (March 2019-February 2020). Multi-organ transplants were excluded. The primary outcome was the need for immediate venoarterial ECMO in the OR following OHT. Univariable statistics were computed across demographic, clinical, operative, and perfusion variables, including oxygen delivery (DO2) measured each minute. RESULTS: Fifty-three OHT were included with a median age of 54 years (interquartile range, 45-61). The primary outcome occurred in eight patients (15.1%). A significantly greater proportion of patients requiring ECMO had ischemic cardiomyopathy (50.0% (4/8) vs. 15.6% (7/45), p = 0.02) and had preoperative ventricular assist devices (37.5% (3/8) vs. 8.9% (4/45), p = 0.03). Median bypass times were longer in the ECMO group (217 vs. 147 minutes, p = 0.001). Phenylephrine doses were nonsignificantly higher in ECMO patients (4.1 vs. 1.9 mg, p = 0.10). No significant differences were observed in single-point median DO2 (275 vs. 294 mL O2/min/m2 BSA, p = 0.17) and nadir DO2 (226 vs. 222, p = 0.94), but increasing time and depth of DO2 below a threshold of 300 mL O2/min/m2 BSA (i.e. area over the DO2 curve (AOC) but below threshold) was significantly associated with the need for postoperative ECMO (p = 0.04). CONCLUSION: This is the first study to examine the relationship of perfusion parameters, including oxygen delivery, to outcomes following heart transplantation. We note that DO2 < 300-AOC was significantly associated with the need for postoperative ECMO following heart transplant. Further study will clarify whether potential DO2 differences in patients who require post-OHT ECMO reflect vasoplegia, or a more causative relationship which might be leveraged to improve outcomes.

Transplant Volume Is Associated With Graft Acceptance Threshold and Center Resource Availability.

BACKGROUND: Heart transplant volume varies significantly among centers. We hypothesized that centers where the transplant team routinely accepts organs previously declined by other centers and where operating room availability is unrestricted have higher transplant volumes. METHODS AND RESULTS: We used the potential transplant recipient sequence number in the United Network for Organ Sharing database as a surrogate for graft acceptance threshold and the number of transplantations occurring on weekends and 8 major holidays as a marker of center resource availability. Centers were classified as low-, medium-, or high-volume if the average annual number of transplants were, respectively, <10, 10-30, or >30 over a 10-year period. From July 12, 2006, to December 31, 2015, 19,054 transplants were performed by 142 centers. There were 59 low-volume centers, 69 medium-volume centers, and 14 high-volume centers with median potential transplant recipient sequence numbers for transplanted candidates of 7 (interquartile range 3-11), 7 (5-10), and 15 (7-40), respectively (P = .002). The median proportion of off-hours transplantations performed by medium-volume centers was 28% (25%-31%) compared with 32% (29%-33%) by high-volume centers (P = .009). Five-year survival was equivalent among all centers (P = .053). CONCLUSIONS: Transplants for candidates with high sequence numbers and unrestricted operating room availability are associated with increased center volume without sacrificing post-transplantation survival.

Treatment With Impella Increases the Risk of De Novo Aortic Insufficiency Post Left Ventricular Assist Device Implant.

BACKGROUND: Impella (Abiomed Inc, Danvers, MA) is a temporary mechanical support device positioned across the aortic valve, and can be used to support patient before LVAD implantation. There are no data on the incidence of aortic insufficiency (AI) in patients supported with Impella as a bridge to durable LVAD implantation. We sought to assess the incidence of AI in patients with Impella support as a bridge to durable left ventricular assist device (LVAD) implantation. METHODS: We reviewed all patients undergoing primary LVAD implantation at the University of Pennsylvania from January 2015 onward, comparing those supported with Impella as temporary mechanical support with those supported by either venoarterial extracorporeal life support or an intra-aortic balloon pump. We reviewed transthoracic echocardiography preoperatively, as well as at 1 week, 1, 3, 6, 9, and 12 months after LVAD implantation. RESULTS: A total of 215 echocardiograms were analyzed in 41 patients. Eleven patients were supported with Impella before LVAD implant-6 patients with Impella alone (5 with Impella CP, 1 with Impella 5.0) and 5 with Impella in conjunction with venoarterial extracorporeal life support (2 with Impella 2.5, 2 with Impella CP, and 1 with Impella 5.0). After LVAD implant, mild or moderate AI developed in 82% of patients supported with Impella (9 of 11) compared with 43% of those without Impella (13 of 30) (P = .038). CONCLUSIONS: Patients supported by Impella as a bridge to durable LVAD have a higher risk of developing AI. Further studies are needed to assess this risk as the use of the Impella increases.