Novel Left Ventricular Unloading Strategies in Patients on Peripheral Venoarterial Extracorporeal Membrane Oxygenation Support

The purpose of this study was to evaluate left ventricular (LV) unloading strategies in patients supported with peripheral venoarterial extracorporeal membrane oxygenation (VA-ECMO). A retrospective review was conducted of all consecutive patients requiring VA-ECMO support for any indication, who underwent novel LV unloading strategies with either direct left atrial venoarterial (LAVA) cannulation or pulmonary artery venoarterial (PAVA) venting, in comparison to Impella and intra-aortic balloon pump (IABP). The primary outcome was successful bridge to transplant, LV assist device, or myocardial recovery. Forty-six patients (63% male, mean age 52.8 ± 17.6 years) were included. Fourteen patients (30%) underwent novel unloading with either LAVA or PAVA, 11 patients (24%) underwent IABP placement, and 21 patients (46%) underwent Impella insertion. In the novel LV unloading cohort, 10 patients (71%) survived to hospital discharge. Four patients (29%) were weaned from ECMO and eight patients (57%) underwent cardiac transplantation. Although a trend favoring cannula-based unloading for the primary outcome was noted, the cohort was too small for statistical significance (79% LAVA/PAVA, 57% Impella, 45% IABP; p = 0.21). However, probability of survival was greater in the LAVA/PAVA cohort compared to Impella and IABP ( p < 0.05). Thus, we demonstrate the efficacy of LA and PA cannulation as an alternative LV unloading strategy for patients supported with peripheral VA-ECMO.

Obesity and Extracorporeal Membrane Oxygenation (ECMO): Analysis of Outcomes

Traditionally, patients with obesity have been deemed ineligible for extracorporeal life support (ELS) therapies such as extracorporeal membrane oxygenation (ECMO), given the association of obesity with chronic health conditions that contribute to increased morbidity and mortality. Nevertheless, a growing body of literature suggests the feasibility, efficacy, and safety of ECMO in the obese population. This review provides an in-depth analysis of the current literature assessing the effects of obesity on outcomes among patients supported with ECMO (venovenous [VV] ECMO in noncoronavirus disease 2019 and coronavirus disease 2019 acute respiratory distress syndrome, venoarterial [VA] ECMO, and combined VV and VA ECMO), offer a possible explanation of the current findings on the basis of the obesity paradox phenomenon, provides a framework for future studies addressing the use of ELS therapies in the obese patient population, and provides guidance from the literature for many of the challenges related to initiating, maintaining, and weaning ELS therapy in patients with obesity.

Heart-Lung Transplantation From Donation After Circulatory Death Using Mobile Normothermic Regional Perfusion

Combined heart-lung transplant (HTLx) is the most durable treatment available for end-stage heart and lung failure. Many patients are unable to receive combined organs due to organ availability and allocation policies prioritizing separate heart or lung transplantation. While an average of 45 HTLxs have been performed per year in the United States half the listed patients do not receive organs. Recently, donation after circulatory death (DCD) utilizing normothermic regional perfusion (NRP) has been utilized for heart allografts with excellent results, and here, we present a case utilizing mobile NRP to procure a heart and lung block from a circulatory death donor and successful implantation for a recipient in a separate center.

Inhibition of angiogenesis in the management of refractory gastrointestinal bleeding in patients with LVAD support

BACKGROUND

Gastrointestinal bleeding (GIB) in patients with continuous flow left ventricular assist devices (CF-LVADs) is often related to GI angiodysplasia (GIAD). We previously reported data on VEGF inhibition with IV bevacizumab in the treatment of LVAD-associated GIAD bleeding, and now present follow-up data on patients treated with IV bevacizumab and/or low-dose oral pazopanib.

METHODS

All consecutive adult patients with LVAD-associated GIB from GIAD treated with bevacizumab or pazopanib, from July 20, 2017 to June 22, 2022, were included in the analysis. Data on hospitalizations, GI endoscopic procedures, and blood transfusions were obtained from first admission for GIB up to a median of 35.7 months following treatment initiation (range 1.3-59.8 months).

RESULTS

Eleven patients (91% male, mean 69.5 ± 8.9 years) were included. Eight patients (73%) received IV bevacizumab, two patients (18%) received oral pazopanib, and one patient (9%) received bevacizumab followed by pazopanib therapy. We observed a significantly decreased number of annualized hospitalizations for GIB (median difference - 2.87, p = 0.002), blood transfusions (median difference - 20.9, p = 0.01), and endoscopies (median difference - 6.95, p = 0.007) in patients pre- and post-anti-angiogenic therapy (bevacizumab and/or pazopanib). Similarly, a significant improvement in these clinical outcomes was noted in the bevacizumab group with decreased annualized hospitalizations (median difference - 2.75, p = 0.014), blood transfusions (median difference - 24.5, p = 0.047), and number of endoscopies (median differences -6.88, p = 0.006).

CONCLUSION

Anti-angiogenic therapy with IV bevacizumab and/or low-dose oral pazopanib appears to provide benefits in patients with LVAD-associated GIB with reduced hospitalizations, blood transfusions, and need for GI endoscopic procedures.

Early national trends of lung allograft use during donation after circulatory death heart procurement in the United States

Objective

Innovative technology such as normothermic regional perfusion and the Organ Care System has expanded donation after circulatory death heart transplantation. We wanted to investigate the impact of donation after circulatory death heart procurement in concurrent lung donation and implantation at a national level.

Methods

We reviewed the United Network for Organ Sharing database for heart donation between December 2019 and March 2022. Donation after circulatory death donors were separated from donation after brain death donors and further categorized based on concomitant organ procurement of lung and heart, or heart only.

Results

A total of 8802 heart procurements consisted of 332 donation after circulatory death donors and 8470 donation after brain death donors. Concomitant lung procurement was lower among donation after circulatory death donors (19.3%) than in donation after brain death donors (38.0%, P < .001). The transplant rate of lungs in the setting of concomitant procurement is 13.6% in donation after circulatory death, whereas it is 38% in donation after brain death (P < .001). Of the 121 lungs from 64 donation after circulatory death donors, 22 lungs were retrieved but discarded (32.2%). Normothermic regional perfusion was performed in 37.3% of donation after circulatory death donors, and there was no difference in lung use between normothermic regional perfusion versus direct procurement and perfusion (20.2% and 18.8%). There was also no difference in 1-year survival between normothermic regional perfusion and direct procurement and perfusion.

Conclusions

Although national use of donation after circulatory death hearts has increased, donation after circulatory death lungs has remained at a steady state. The implantation of lungs after concurrent procurement with the heart remains low, whereas transplantation of donation after circulatory death hearts is greater than 90%. The use of normothermic regional perfusion lungs has been controversial, and we report comparable 1-year outcomes to standard donation after circulatory death lungs. Further studies are warranted to investigate the underlying mechanisms of normothermic regional perfusion on lung function.

Infections in Patients With Left Ventricular Assist Devices: Current State and Future Perspectives

Mechanical circulatory support is increasingly being used as bridge-to-transplant and destination therapy in patients with advanced heart failure. Technologic improvements have led to increased patient survival and quality of life, but infection remains one of the leading adverse events following ventricular assist device (VAD) implantation. Infections can be classified as VAD-specific, VAD-related, and non-VAD infections. Risk of VAD-specific infections, such as driveline, pump pocket, and pump infections, remains for the duration of implantation. While adverse events are typically most common early (within 90 days of implantation), device-specific infection (primarily driveline) is a notable exception. No diminishment over time is seen, with event rates of 0.16 events per patient-year in both the early and late periods postimplantation. Management of VAD-specific infections requires aggressive treatment and chronic suppressive antimicrobial therapy is indicated when there is concern for seeding of the device. While surgical intervention/hardware removal is often necessary in prosthesis-related infections, this is not so easily accomplished with VADs. This review outlines the current state of infections in patients supported with VAD therapy and discusses future directions, including possibilities with fully implantable devices and novel approaches to treatment.

Expanded extracorporeal membrane oxygenation bridge to heart and lung transplant candidate selection does not impact outcomes compared to traditional candidate selection criteria

Extracorporeal membrane oxygenation is used as a bridge to transplant (ECMO-BTT) in selected patients. The objective of this study was to determine whether 1-year post-transplant and post-ECMO survival are impacted by traditional compared to expanded selection criteria. We performed a retrospective study of patients >17 years who received ECMO as bridge to transplant (BTT) or bridge to transplant decision for lung or combined heart and lung transplantation at the Mayo Clinic Florida and Rochester. Institutional protocol excludes patients >55 years, maintained on steroids, unable to participate in physical therapy, with body mass index >30 or <18.5 kg/m², non-pulmonary end-organ dysfunction, or unmanageable infections from ECMO-BTT. For this study, adherence to this protocol was considered traditional whereas exceptions to the protocol were considered expanded selection criteria. A total of 45 patients received ECMO as bridge therapy. Out of those 29 patients (64%) received ECMO as bridge to transplant and 16 patients (36%) as bridge to transplant decision. The traditional criteria cohort consisted of 15 (33%) patients and expanded criteria cohort consisted of 30 (67%) patients. In the traditional cohort, 9 (60%) of 15 patients were successfully transplanted compared to 16 (53%) of 30 patients in the expanded criteria cohort. No difference in being delisted or dying on the waitlist (OR: 0.58, CI: 0.13-2.58), surviving to 1-year post-transplant (OR: 0.53, CI: 0.03-9.71) or 1-year post-ECMO (OR: 0.77, CI: 0.0.23-2.56) was observed between the traditional criteria and expanded criteria cohorts. At our institution, we did not see differences in odds of 1-year post-transplant and post-ECMO survival between those who met traditional criteria compared to those who did not. Multicenter, prospective studies are needed to evaluate the impact of ECMO-BTT selection criteria.

Cardiac Transplantation: Physiology and Natural History of the Transplanted Heart

Heart transplantation (HT) is one of the prodigious achievements in modern medicine and remains the cornerstone in the treatment of patients with advanced heart failure. Advances in surgical techniques, immunosuppression, organ preservation, infection control, and allograft surveillance have improved short- and long-term outcomes thereby contributing to greater clinical success of HT. However, prolonged allograft and patient survival following HT are still largely restricted by the development of late complications, including allograft rejection, infection, cardiac allograft vasculopathy (CAV), and malignancy. The introduction of mTOR inhibitors early after HT has demonstrated multiple protective effects against CAV progression, renal dysfunction, and tumorigenesis. Therefore, several HT programs increasingly use mTOR inhibitors with partial or complete withdrawal of calcineurin inhibitor (CNI) in stable HT patients to reduce complications risk and improve long-term outcomes. Furthermore, despite a substantial improvement in exercise capacity and health-related quality of life after HT as compared to advanced heart failure patients, most HT recipients remain with a 30% to 50% lower peak oxygen consumption (Vo ₂ ) than that of age-matched healthy subjects. Several factors, including alterations in central hemodynamics, HT-related complications and alterations in the musculoskeletal system, and peripheral physiological abnormalities, presumably contribute to the reduced exercise capacity following HT. Cardiac denervation and subsequent loss of sympathetic and parasympathetic regulation are responsible for various physiological alterations in the cardiovascular system, which contributes to restricted exercise tolerance. Restoration of cardiac innervation may improve exercise capacity and quality of life, but the reinnervation process is only partial even several years after HT. Multiple studies have shown that aerobic and strengthening exercise interventions improve exercise capacity by increasing maximal heart rate, chronotropic response, and peak Vo ₂ after HT. Novel exercise modalities, such as high-intensity interval training (HIT), have been proven as safe and effective for further improvement in exercise capacity, including among de novo HT recipients. Further developments have recently emerged, including donor heart preservation techniques, noninvasive CAV and rejection surveillance methods, and improvements in immunosuppressive therapies, all aiming at increasing donor availability and improving late survival after HT. © 2023 American Physiological Society. Compr Physiol 13:4719-4765, 2023.

Preemptive antiviral therapy in lung transplantation from hepatitis C donors results in a rapid and sustained virologic response

Objective

The study objective was to assess the safety and efficacy of a preemptive direct-acting antiviral therapy in lung transplants from hepatitis C virus donors to uninfected recipients.

Methods

This study is a prospective, open-label, nonrandomized, pilot trial. Recipients of hepatitis C virus nucleic acid test positive donor lungs underwent preemptive direct-acting antiviral therapy with glecaprevir 300 mg/pibrentasvir 120 mg for 8 weeks from January 1, 2019, to December 31, 2020. Recipients of nucleic acid test positive lungs were compared with recipients of lungs from nucleic acid test negative donors. Primary end points were Kaplan-Meier survival and sustained virologic response. Secondary outcomes included primary graft dysfunction, rejection, and infection.

Results

Fifty-nine lung transplantations were included: 16 nucleic acid test positive and 43 nucleic acid test negative. Twelve nucleic acid test positive recipients (75%) developed hepatitis C virus viremia. Median time to clearance was 7 days. All nucleic acid test positive patients had undetectable hepatitis C virus RNA by week 3, and all alive patients (n = 15) remained negative during follow-up with 100% sustained virologic response at 12 months. One nucleic acid test positive patient died of primary graft dysfunction and multiorgan failure. Three of 43 nucleic acid test negative patients (7%) had hepatitis C virus antibody positive donors. None of them developed hepatitis C virus viremia. One-year survival was 94% for nucleic acid test positive recipients and 91% for nucleic acid test negative recipients. There was no difference in primary graft dysfunction, rejection, or infection. One-year survival for nucleic acid test positive recipients was similar to a historical cohort of the Scientific Registry of Transplant Recipients (89%).

Conclusions

Recipients of hepatitis C virus nucleic acid test positive lungs have similar survival as recipients of nucleic acid test negative lungs. Preemptive direct-acting antiviral therapy results in rapid viral clearance and sustained virologic response at 12 months. Preemptive direct-acting antiviral may partially prevent hepatitis C virus transmission.

Pulsatile Pressure Delivery of Continuous-Flow Left Ventricular Assist Devices Is Markedly Reduced Relative to Heart Failure Patients

Although continuous-flow left ventricular assist devices (CF-LVADs) provide an augmentation in systemic perfusion, there is a scarcity of in vivo data regarding systemic pulsatility on support. Patients supported on CF-LVAD therapy (n = 71) who underwent combined left/right catheterization ramp study were included. Aortic pulsatility was defined by the pulsatile power index (PPI), which was also calculated in a cohort of high-output heart failure (HOHF, n = 66) and standard HF cohort (n = 44). PPI was drastically lower in CF-LVAD-supported patients with median PPI of 0.006 (interquartile range [IQR], 0.002-0.012) compared with PPI in the HF population at 0.09 (IQR, 0.06-0.17) or HOHF population at 0.25 (IQR, 0.13-0.37; p < 0.0001 among groups). With speed augmentation during ramp, PPI values fell quickly in patients with higher PPI at baseline. PPI correlated poorly with left ventricular ejection fraction (LVEF) in all groups. In CF-LVAD patients, there was a stronger correlation with LV dP/dt (r = 0.41; p = 0.001) than LVEF (r = 0.21; p = 0.08; pint < 0.001). CF-LVAD support is associated with a dramatic reduction in arterial pulsatility as measured by PPI relative to HOHF and HF cohorts and decreases with speed. Further work is needed to determine the applicability to the next generation of device therapy.

Heart Transplantation from COVID-19-Positive Donors: A Word of Caution

BACKGROUND

During the COVID-19 pandemic, efforts to maintain solid-organ transplantation have continued, including the use of SARS-CoV-2-positive heart donors.

METHODS

We present our institution's initial experience with SARS-CoV-2-positive heart donors. All donors met our institution's Transplant Center criteria, including a negative bronchoalveolar lavage polymerase chain reaction result. All but 1 patient received postexposure prophylaxis with anti-spike monoclonal antibody therapy, remdesivir, or both.

RESULTS

A total of 6 patients received a heart transplant from a SARS-CoV-2-positive donor. One heart transplant was complicated by catastrophic secondary graft dysfunction requiring venoarterial extracorporeal membrane oxygenation and retransplant. The remaining 5 patients did well postoperatively and were discharged from the hospital. None of the patients had evidence of COVID-19 infection after surgery.

CONCLUSION

Heart transplants from SARS-CoV-2 polymerase chain reaction-positive donors are feasible and safe with adequate screening and postexposure prophylaxis.

Induction therapy in lung transplantation: A contemporary analysis of trends and outcomes

OBJECTIVES

We provide a contemporary consideration of long-term outcomes and trends of induction therapy use following lung transplantation in the United States.

METHODS

We reviewed the United Network for Organ Sharing registry from 2006 to 2018 for first-time, adult, lung-only transplant recipients. Long-term survival was compared between induction classes (Interleukin-2 inhibitors, monoclonal or polyclonal cell-depleting agents, and no induction therapy). A 1:1 propensity score match was performed, pairing patients who received basiliximab with similar risk recipients who did not receive induction therapy. Outcomes in matched populations were compared using Cox, Kaplan-Meier and Logistic regression modeling.

MEASUREMENTS AND MAIN RESULTS

22 025 recipients were identified; 8003 (36.34%) were treated with no induction therapy, 11 045 (50.15%) with basiliximab, 1556 (7.06%) with alemtuzumab and 1421 (6.45%) with anti-thymocyte globulin. Compared with those who received no induction, patients receiving basiliximab, alemtuzumab or anti-thymocyte globulin were found on multivariable Cox-regression analyses to have lower long-term mortality (all p < .05). Following propensity score matching of basiliximab and no induction populations, analyses demonstrated a statistically significant association between basiliximab use and long- term survival (p < .001). Basiliximab was also associated with a lower risk of acute rejection (p < .001) and renal failure (p = .002).

CONCLUSION

Induction therapy for lung transplant recipients-specifically basiliximab-is associated with improved long-term survival and a lower risk of renal failure or acute rejection.

Lung transplantation for chronic obstructive pulmonary disease: A call to modify the lung allocation score to decrease waitlist mortality

OBJECTIVE

Approximately 40% of lung transplants for chronic obstructive pulmonary disease (COPD) in the lung allocation score era are single lung transplantations (SLTs). We hypothesized that double lung transplantation (DLT) results in superior survival, but that mortality on the waitlist may compel clinicians to perform SLT. We investigated both waitlist mortality in COPD patients with restricted versus unrestricted listing preferences and posttransplant survival in SLT versus DLT to identify key predictors of mortality.

METHODS

A retrospective analysis of waitlist mortality and posttransplant survival in patients with COPD was conducted using post-lung allocation score data from the United Network for Organ Sharing database between 2005 and 2018.

RESULTS

Of 6740 patients with COPD on the waitlist, 328 (4.87%) died and 320 (4.75%) were removed due to clinical deterioration. Median survival on the waitlist was significantly worse in patients listed as restricted for DLT (4.39 vs 6.09 years; P = .002) compared with patients listed as unrestricted (hazard ratio, 1.34; 95% CI, 1.13-1.57). Factors that increase waitlist mortality include female sex, increased pulmonary artery pressure, and increased wait time. Median posttransplant survival was 5.3 years in SLT versus 6.5 years in DLT (P < .001). DLT recipients are younger, male patients with a higher lung allocation score. The survival advantage of DLT persisted in adjusted analysis (hazard ratio, 0.819; 95% CI, 0.741-0.905).

CONCLUSIONS

Restricted listing preference is associated with increased waitlist mortality, but DLT recipients have superior posttransplant survival. Because the lung allocation score does not prioritize COPD, concern for increased waitlist mortality with restricted listing preference may drive continued use of SLT despite better posttransplant survival in DLT.

Lung Transplantation Long-term Survival is Worse in Patients Who Have Undergone Previous Cardiac Surgery

OBJECTIVE

Approximately 10% of lung transplant recipients have had previous cardiothoracic surgery. We sought to determine if previous surgery affects outcomes after lung transplant at a national level.

METHODS

The United Network for Organ Sharing database was analyzed from 2005-2019 to include adult patients who underwent lung transplant who had previous cardiac surgery, and previous thoracic surgery. T-test and chi-squared analysis was used to compare perioperative outcomes. Long-term survival comparison was performed using the Kaplan-Meier method in an unadjusted and propensity matched analysis.

RESULTS

Out of 24,784 lung transplants, 691 (2.7%) had previous cardiac surgery and 1,321 (6.5%) had previous thoracic surgery. Operative mortality was worse in previous cardiac surgery 42(6.1%) versus no previous cardiac surgery 740(3.1%), p < 0.001, and in previous thoracic surgery 65(4.9%) versus no previous thoracic surgery 717(3.1%), p < 0.001. The previous thoracic surgery group had more primary graft failure and treated rejection during the first-year post-transplant. There was no difference in stroke, dialysis, intubation and extracorporeal membrane oxygenation at 72 hours. Long-term survival was significantly worse for lung transplant patients who had undergone previous cardiac surgery (median 3.8 vs 6.3 years, p < 0.001) due to an increase in cardiovascular deaths (p = 0.008) and malignancy (p = 0.043). However, there was no difference in previous thoracic surgery (median 6.6 vs 6.1 years, p = 0.337).

CONCLUSIONS

Previous cardiac surgery prior to lung transplant results in worse survival related to cardiovascular death and malignancies. Previous thoracic surgery worsens perioperative outcomes but does not affect long term survival.

Coronary Artery Bypass Grafting in Octogenarians-Risks, Outcomes, and Trends in 1283 Consecutive Patients

OBJECTIVE

To describe the risks, outcomes, and trends in patients older than 80 years undergoing coronary artery bypass grafting (CABG).

METHODS

We retrospectively studied 1283 consecutive patients who were older than 80 years and underwent primary isolated CABG from January 1, 1993, to October 31, 2019, in our clinic. Kaplan-Meier survival probability and quartile estimates were used to analyze patients' survival. Logistic regression models were used for analyzing temporal trends in CABG cases and outcomes. A multivariable Cox proportional hazards regression model was developed to study risk factors for mortality.

RESULTS

Operative mortality was overall 4% (n=51) but showed a significant decrease during the study period (P=.015). Median follow-up was 16.7 (interquartile range, 10.3-21.1) years, and Kaplan-Meier estimated survival rates at 1 year, 5 years, 10 years, and 15 years were 90.2%, 67.9%, 31.1%, and 8.2%, respectively. Median survival time was 7.6 years compared with 6.0 years for age- and sex-matched octogenarians in the general US population (P<.001). Multivariable Cox regression analysis identified older age (P<.001), recent atrial fibrillation or flutter (P<.001), diabetes mellitus (P<.001), smoking history (P=.006), cerebrovascular disease (P=.04), immunosuppressive status (P=.01), extreme levels of creatinine (P<.001), chronic lung disease (P=.02), peripheral vascular disease (P=.02), decreased ejection fraction (P=.03) and increased Society of Thoracic Surgeons predicted risk score (P=.01) as significant risk factors of mortality.

CONCLUSION

Although CABG in octogenarians carries a higher surgical risk, it may be associated with favorable outcomes and increase in long-term survival. Further studies are warranted to define subgroups benefiting more from surgical revascularization.

Physiology of Continuous-Flow Left Ventricular Assist Device Therapy

The expanding use of continuous-flow left ventricular assist devices (CF-LVADs) for end-stage heart failure warrants familiarity with the physiologic interaction of the device with the native circulation. Contemporary devices utilize predominantly centrifugal flow and, to a lesser extent, axial flow rotors that vary with respect to their intrinsic flow characteristics. Flow can be manipulated with adjustments to preload and afterload as in the native heart, and ascertainment of the predicted effects is provided by differential pressure-flow (H-Q) curves or loops. Valvular heart disease, especially aortic regurgitation, may significantly affect adequacy of mechanical support. In contrast, atrioventricular and ventriculoventricular timing is of less certain significance. Although beneficial effects of device therapy are typically seen due to enhanced distal perfusion, unloading of the left ventricle and atrium, and amelioration of secondary pulmonary hypertension, negative effects of CF-LVAD therapy on right ventricular filling and function, through right-sided loading and septal interaction, can make optimization challenging. Additionally, a lack of pulsatile energy provided by CF-LVAD therapy has physiologic consequences for end-organ function and may be responsible for a series of adverse effects. Rheological effects of intravascular pumps, especially shear stress exposure, result in platelet activation and hemolysis, which may result in both thrombotic and hemorrhagic consequences. Development of novel solutions for untoward device-circulatory interactions will facilitate hemodynamic support while mitigating adverse events. © 2021 American Physiological Society. Compr Physiol 12:1-37, 2021.

How to Turn It Down: The Evidence and Opinions Behind Adult Venoarterial Extracorporeal Membrane Oxygenation Weaning

Adequate and durable recovery in patients supported with venoarterial (VA) extracorporeal membrane oxygenation (ECMO) can be challenging to predict. Extracorporeal membrane oxygenation weaning is the process by which the ECMO flows are decreased to assess if a patient is ready for decannulation. The optimal strategies for deciding who to wean and how to wean VA ECMO remain undefined. A retrospective literature review was performed to understand the evidence supporting current practices in ECMO weaning and in particular patient selection and methods. Most published work and expert opinions agree that once the underlying process has resolved, the minimum required physiologic parameters for weaning from ECMO include: hemodynamic stability and cardiac pulsatility, adequate lung function to support oxygenation and ventilation, and evidence of recovered end organ function. Echocardiography is universally used to assess cardiac function during the weaning process. Currently, there is no consensus regarding who is eligible to wean or how to wean ECMO in adults. We have reviewed the literature to summarize the evidence and expert opinions behind VA ECMO weaning, and give an example of the protocol used at our center. We believe this protocol optimizes patient selection for weaning and helps to predict successful decannulation.

Extracorporeal cardiopulmonary resuscitation (ECPR) survival: A quaternary center analysis

BACKGROUND

Extracorporeal cardiopulmonary resuscitation (ECPR) has emerged as a rescue strategy for nonresponders to conventional CPR (CCPR) in cardiac arrest. Definitive guidelines for ECPR deployment do not exist. Prior studies suggest that arrest rhythm and cardiac origin of arrest may be variables used to assess candidacy for ECPR.

AIM

To describe a single-center experience with ECPR and to assess associations between survival and physician-adjudicated origin of arrest and arrest rhythm.

METHODS

A retrospective review of all patients who underwent ECPR at a quaternary care center over a 7-year period was performed. Demographic and clinical characteristics were extracted from the medical record and used to adjudicate the origin of cardiac arrest, etiology, rhythm, survival, and outcomes. Univariate analysis was performed to determine the association of patient and arrest characteristics with survival.

RESULTS

Between 2010 and 2017, 47 cardiac arrest patients were initiated on extracorporeal membrane oxygenation (ECMO) at the time of active CPR. ECPR patient survival to hospital discharge was 25.5% (n = 12). Twenty-six patients died on ECMO (55.3%) while nine patients (19.1%) survived decannulation but died before discharge. Neither physician-adjudicated arrest rhythm nor underlying origin were significantly associated with survival to discharge, either alone or in combination. Younger age was significantly associated with survival. Nearly all survivors experienced myocardial recovery and left the hospital with a good neurological status.

CONCLUSIONS

Arrest rhythm and etiology may be insufficient predictors of survival in ECPR utilization. Further multiinstitutional studies are needed to determine evidenced-based criteria for ECPR deployment.

Factors Related to Survival in Low-Glomerular Filtration Rate Cohorts Undergoing Lung Transplant

BACKGROUND

Historically, a glomerular filtration rate (GFR) of less than 50 mL/min per 1.73 m² has been considered a contraindication to lung transplantation. Combined or sequential lung-kidney transplantation is an option for those with a GFR less than 30 mL/min per 1.73 m². Patients with a GFR of 30 to 50 mL/min per 1.73 m² are provided with no options for transplantation. This study explores factors associated with improved survival in patients who undergo isolated lung transplantation with a GFR of 30 to 50 mL/min per 1.73 m².

METHODS

The United Network for Organ Sharing database was queried for adult patients undergoing primary isolated lung transplantation between January 2007 and March 2018. Regression models were used to identify factors associated with improved survival in lung recipients with a preoperative GFR of 30 to 50 mL/min per 1.73 m². The propensity score method was used to match highly performing patients (outpatient recipients aged less than 60 years) with a GFR of 30 to 50 mL/min per 1.73 m² with patients who had a GFR greater than 50 mL/min per 1.73 m². Kaplan-Meier, Cox, and logistic regression analyses compared outcomes in matched populations.

RESULTS

A total of 21,282 lung transplantations were performed during the study period. Compared with patients with a GFR greater than 50 mL/min per 1.73 m², survival was significantly worse for patients with a GFR of 30 to 50 mL/min per 1.73 m². Multivariate analysis of patients with a GFR of 30 to 50 mL/min per 1.73 m² demonstrated outpatient status and age less than 60 years to be predictive of superior survival. After propensity matching, survival of this highly performing subset with a GFR of 30 to 50 mL/min per 1.73 m² was no different from that of patients with a normal GFR.

CONCLUSIONS

Outpatient recipients aged less than 60 years represent an optimal subset of patients with a GFR of 30 to 50 mL/min per 1.73 m². Lung transplant listing should not be declined based only on a GFR less than 50 mL/min per 1.73 m².

Trends in the use of hepatitis C viremic donor hearts

OBJECTIVE

To examine trends in utilization of hearts from hepatitis C virus (HCV) viremic donors for transplantation, a strategy to expand organ availability.

METHODS

The United Network for Organ Sharing (UNOS) registry was queried for adult patients undergoing heart transplantation between 2015 and 2019. We excluded multiorgan transplants, incomplete data, and loss to follow-up. Nucleic acid testing (NAT) defined HCV status.

RESULTS

Between 2015 and 2019, a total of 11,393 adults underwent heart transplantation: 326 from HCV NAT⁺ donors and 11,067 from NAT^- donors. The use of NAT⁺ hearts increased from 1 in 2015 to 137 in 2018 against a static number of NAT^- organs. The use of NAT⁺ hearts varied significantly across regions and individual centers. More than 75% of NAT⁺ hearts were transplanted in the Northeast region, leading to further travel (mean, 299 miles vs 173 miles for NAT^- transplantations; P < .001), with longer ischemic times (mean: 3.52 hours vs 3.10 hours; P < .001). More than one-half of NAT⁺ transplantations were performed by 5 individual centers, and a single institution accounted for >20% of all transplantations from viremic donors. Survival in the 2 groups did not differ by Kaplan-Meier analysis (P = .240), and multivariable regression showed no differences in acute rejection (P = .455) or 30-day mortality (P = .490). Of the 326 recipients of NAT⁺ hearts, 38 seroconverted and 14 became viremic within 1 year. Survival was 100% in the viremic patients and 97.4% in seroconverted patients at 1 year.

CONCLUSIONS

Heart transplantation from HCV viremic donors continues to increase but varies significantly across UNOS regions and individual centers. Short-term outcomes are comparable, but effects of seroconversion and long-term outcomes remain unclear.

Veno-venous Extracorporeal Membrane Oxygenation for Respiratory Failure in COVID-19 Patients: Early Experience From a Major Academic Medical Center in North America

AND BACKGROUND DATA

VV ECMO can be utilized as an advanced therapy in select patients with COVID-19 respiratory failure refractory to traditional critical care management and optimal mechanical ventilation. Anticipating a need for such therapies during the pandemic, our center created a targeted protocol for ECMO therapy in COVID-19 patients that allows us to provide this life-saving therapy to our sickest patients without overburdening already stretched resources or excessively exposing healthcare staff to infection risk.

METHODS

As a major regional referral program, we used the framework of our well-established ECMO service-line to outline specific team structures, modified patient eligibility criteria, cannulation strategies, and management protocols for the COVID-19 ECMO program.

RESULTS

During the first month of the COVID-19 outbreak in Massachusetts, 6 patients were placed on VV ECMO for refractory hypoxemic respiratory failure. The median (interquartile range) age was 47 years (43-53) with most patients being male (83%) and obese (67%). All cannulations were performed at the bedside in the intensive care unit in patients who had undergone a trial of rescue therapies for acute respiratory distress syndrome including lung protective ventilation, paralysis, prone positioning, and inhaled nitric oxide. At the time of this report, 83% (5/6) of the patients are still alive with 1 death on ECMO, attributed to hemorrhagic stroke. 67% of patients (4/6) have been successfully decannulated, including 2 that have been successfully extubated and one who was discharged from the hospital. The median duration of VV ECMO therapy for patients who have been decannulated is 12 days (4-18 days).

CONCLUSIONS

This is 1 the first case series describing VV ECMO outcomes in COVID-19 patients. Our initial data suggest that VV ECMO can be successfully utilized in appropriately selected COVID-19 patients with advanced respiratory failure.

Failure to rescue in the era of the lung allocation score: The impact of center volume

BACKGROUND

Failure to Rescue (FTR) is a valuable surgical quality improvement metric. The aim of this study is to assess the relationship between center volume and FTR following lung transplantation.

METHODS

Using the database of the United Network for Organ Sharing (UNOS) all adult, primary, isolated lung recipients in the United States between May 2005 and March 2016 were identified. FTR was defined as operative mortality after any of five specific complications. FTR was compared across terciles of transplantation centers stratified based on operative volume.

RESULTS

17,185 lung recipients met study criteria. The composite FTR rate (Death following at least one complication) was 20.7%. Following stratification by volume, FTR rates increased from high to middle tercile centers (19.3% vs. 23.0%). Multivariate logistic regression models suggested an independent relationship between higher center volume and lower FTR rates (p < 0.001).

CONCLUSION

Higher volume lung transplantation centers have lower rates of failure to rescue.

Increasing donor sequence number is not associated with inferior outcomes in lung transplantation

BACKGROUND

Donor sequence number (DSN) represents the number of recipients to whom an organ has been offered. The impact of seeing numerous prior refusals may potentially influence the decision to accept an organ. We sought to determine if DSN was associated with inferior posttransplant outcomes.

METHODS

Using the United Network for Organ Sharing database, a retrospective analysis was performed on 22 361 patients who received a lung transplant between 2005 and 2017. Patients were grouped into low DSN (1-24, n = 16 860) and high DSN (>24, n = 5501) categories. Baseline characteristics and posttransplant outcomes were analyzed. An institutional subgroup was also analyzed to compare rates of primary graft dysfunction (PGD) posttransplant.

RESULTS

The DSN ranged from 1 to 1735 (median, 7; interquartile range, 2-24). A total of 18 507 recipients received an organ with at least one prior refusal. Recipients of donors with a higher DSN were older (58 vs 55 years; P < .01) but had lower lung allocation scores (43.5 vs 47.5; P < .01). On adjusted analysis, high DSN was not associated with increased mortality (hazard ratio, 0.99; 95% confidence interval, 0.94-1.04; P = .77). There was no difference in the incidence of graft failure (P = .37) or retransplantation (P = .24). Recipient subgroups who received donors with an increasing DSN >50 and >75 also demonstrated no difference in mortality when compared with a low DSN (P = .86 and P = .97). There was no difference in PGD for patients with a low vs a high DSN at any time posttransplant.

CONCLUSIONS

DSN is not associated with increased mortality in patients undergoing lung transplantation and should not negatively influence the decision to accept a lung for transplant.

Failure to Rescue Contributes to Center-Level Differences in Mortality After Lung Transplantation

BACKGROUND

The clinical response to postoperative complications after lung transplantation (LTx) may contribute to mortality differences among transplantation centers. The ability to avoid mortality after a complication-failure to rescue (FTR)-may be an effective quality metric in LTx.

METHODS

The United Network for Organ Sharing database was queried for adult, first-time, lung-only transplantations from May 2005 to December 2015. Transplantation centers were stratified into equal-sized terciles on the basis of observed operative mortality rates. Several postoperative complications were identified, including stroke, acute rejection, acute kidney injury requiring hemodialysis, airway dehiscence, and extracorporeal membrane oxygenation 72 hours after surgery. Rates of FTR were calculated as the number of operative mortalities in patients who had complications divided by the number of patients who had any postoperative complications.

RESULTS

Our study population included 16,411 LTx operations performed at 69 transplantation centers. LTx centers were stratified into terciles with average perioperative mortality of 4.0% for low-mortality centers, 6.9% for intermediate-mortality centers, and 12.4% for high-mortality centers. Low-mortality centers had slightly lower complication rates (low, 15.0% vs intermediate, 17.1% vs high, 19.1%; P < .001). Differences in FTR rate were significantly more pronounced (low, 14.9% vs intermediate, 23.9% vs high, 34.2%; P < .001). Multivariable logistic regression and generalized linear models demonstrated an independent association between high FTR rates and high mortality in LTx (P < .001).

CONCLUSIONS

Differences in rates of FTR contribute significantly to per-center variability in mortality after LTx. FTR can serve as a quality metric to identify opportunities for improvement in management of perioperative adverse events.

Portable normothermic ex-vivo lung perfusion, ventilation, and functional assessment with the Organ Care System on donor lung use for transplantation from extended-criteria donors (EXPAND): a single-arm, pivotal trial

BACKGROUND

Donor lung use for transplantation is the lowest among solid organ tranplants because of several complex and multifactorial reasons; one area that could have a substantial role is the limited capabilities of cold ischaemic storage. The aim of the EXPAND trial was to evaluate the efficacy of normothermic portable Organ Care System (OCS) Lung perfusion and ventilation on donor lung use from extended-criteria donors and donors after circulatory death, which are rarely used.

METHODS

In this single-arm, pivotal trial done in eight institutions across the USA, Germany, and Belgium, lungs from extended-criteria donors were included if fulfilling one or more of the following criteria: a ratio of partial pressure of arterial oxygen (PaO₂) to fractional concentration of oxygen inspired air (FiO₂) in the donor lung of 300 mm Hg or less; expected ischaemic time longer than 6 h; donor age 55 years or older; or lungs from donors after circulatory death that were recruited and assessed using OCS Lung. Lungs were transplanted if they showed stability of OCS Lung variables, PaO₂:FiO₂ was more than 300 mm Hg, and they were accepted by the transplanting surgeon. Patients were adult bilateral lung transplant recipients. The primary efficacy endpoint was a composite of patient survival at day 30 post-transplant and absence of The International Society for Heart & Lung Tranplantation primary-graft dysfunction grade 3 (PGD3) within 72 h post-transplantation, with a prespecified objective performance goal of 65%. The primary analysis population was all transplanted recipients. This trial is registered with ClinicalTrials.gov, number NCT01963780, and is now complete.

FINDINGS

Between Jan 23, 2014, and Oct 23, 2016, 93 lung pairs were perfused, ventilated, and assessed on the OCS Lung. 12 lungs did not meet OCS transplantation criteria so 81 lungs were suitable for transplantation. Two lungs were excluded for logistical reasons, hence 79 (87%) of eligible lungs were transplanted. The primary endpoint was achieved in 43 (54%) of 79 patients and did not meet the objective performance goal. 35 (44%) of 79 patients had PGD3 within the initial 72 h. 78 (99%) of 79 patients had survived at 30 days post-transplant. The mean number of lung graft-related serious adverse events (respiratory failure and major pulmonary-related infection) was 0·3 events per patient (SD 0·5).

INTERPRETATION

Despite missing the objective primary endpoint, the portable OCS Lung resulted in 87% donor lung use for transplantation with excellent clinical outcomes. Many lungs declined by other transplant centres were successfully transplanted using this new technology, which implies its use has the potential to increase the number of lung transplants performed worldwide. Whether similar outcomes could be obtained if these lungs were preserved on ice is unknown and remains an area for future research.

FUNDING

TransMedics Inc.

Pre-emptive pangenotypic direct acting antiviral therapy in donor HCV-positive to recipient HCV-negative heart transplantation: an open-label study

BACKGROUND

Low donor heart availability underscores the need to identify all potentially transplantable organs. We sought to determine whether pre-emptive administration of pangenotypic direct-acting antiviral therapy can safely prevent the development of chronic hepatitis C virus (HCV) infection in uninfected recipients of HCV-infected donor hearts.

METHODS

Patients were recruited for this an open-label, single-centre, proof-of-concept study from Nov 1, 2017, to Nov 30, 2018. Following enrolment, the recipient's status on the heart transplantation waiting list was updated to reflect a willingness to accept either an HCV-positive or HCV-negative heart donor. Patients who underwent transplantation with a viraemic donor heart, as determined by nucleic acid testing (NAT), received pre-emptive oral glecaprevir-pibrentasvir before transport to the operating room followed by an 8-week course of glecaprevir-pibrentasvir after transplantation. Patients receiving HCV antibody-positive donor hearts without detectable circulating HCV RNA were followed using a reactive approach and started glecaprevir-pibrentasvir only if they developed viraemia. The primary outcome was achievement of sustained virological response 12 weeks after completion of glecaprevir-pibrentasvir therapy (SVR12). Patients were followed from study enrolment to 1 year after transplantation. This is an interim analysis, initiated after all enrolled patients reached the primary outcome. Results reflect data from Nov 1, 2017, to May 30, 2019. This trial is registered with ClinicalTrials.gov, number NCT03208244.

FINDINGS

55 patients were assessed for eligibility and 52 consented to enrolment. 25 patients underwent heart transplantation with HCV-positive donor hearts (20 NAT-positive, five NAT-negative), three of whom underwent simultaneous heart-kidney transplantation. All 20 recipients of NAT-positive hearts tolerated glecaprevir-pibrentasvir and showed rapid viral suppression (median time to clearance 3·5 days, IQR 0·0-8·3), with the subsequent achievement of SVR12 by all 20. The five recipients of NAT-negative grafts did not become viraemic. Median pre-transplant waiting time for patients following enrolment in the HCV protocol was 20 days (IQR 8-57). Patient and allograft survival were 100% at a median follow-up of 10·7 months (range 6·5-18·0).

INTERPRETATION

Pre-emptive administration of glecaprevir-pibrentasvir therapy results in expedited organ transplantation, rapid HCV suppression, prevention of chronic HCV infection, and excellent early allograft function in patients receiving HCV-infected donor hearts. Long-term outcomes are not yet known.

FUNDING

American Association for the Study of Liver Diseases, National Institutes of Health, and the Massachusetts General Hospital.

Cardiac Surgery Trainees as "Skin-to-Skin" Operating Surgeons: Midterm Outcomes

BACKGROUND

We have previously demonstrated that cardiac surgery trainees can safely perform operations "skin-to-skin" with adequate attending surgeon supervision.

METHODS

We used 100 consecutive cases (82 coronary artery bypass grafts, 9 aortic valve replacements, 7 coronary artery bypass grafts plus aortic valve replacements, 2 others) performed by residents (group R) to match 1:1 by procedure to nonconsecutive cases done by a single attending surgeon (group A) from July 2014 to October 2016. Patients were stratified based on whether the attending surgeon or trainee performed every critical step of the operation skin-to-skin. Outcomes included death, major morbidity, and readmission.

RESULTS

Patients in the two groups were similar with respect to demographic characteristics and comorbidities. The median follow-up time for patients in this study was 28 months (interquartile range: 23 to 35 months). There were seven deaths (3.5%; four in group A, three in group R, p = 0.7). Of the 43 patients (21.5%) who were readmitted during the study term, 27 patients (13.5%) were readmitted for causes related to the operation (11 in group A, 16 in group R, p = 0.02). The most common reasons for readmissions related to the operation were chest pain (n = 11), pleural effusion that required drainage (n = 8), pneumonia (n = 4), and unstable angina that required percutaneous coronary intervention (n = 3). No statistically significant differences were found in reasons for readmission between group A and group R.

CONCLUSIONS

The equivalence of postoperative outcomes previously demonstrated at 30 days persists at midterm follow-up. Our data indicate that trainees can be educated in operative cardiac surgery under the current paradigm without sacrificing outcome quality. It is reasonable to expect academic programs to continue providing trainees with experience as primary operating surgeons.

The effect of donor age on posttransplant mortality in a cohort of adult cardiac transplant recipients aged 18-45

Hearts from older donors are increasingly utilized for transplantation due to unmet demand. Conflicting evidence exists regarding the prognosis of recipients of advanced age donor hearts, especially in young recipients. A retrospective analysis was performed on 11 433 patients aged 18 to 45 who received a cardiac transplant from 2000 to 2017. Overall, 10 279 patients received hearts from donors less than 45 and 1145 from donors greater than 45. Recipients of older donors were older (37 vs. 34 years, P < .01) and had higher rates of inotropic dependence (48% vs. 42%, P < .01). However, groups were similar in terms of comorbidities and dependence on mechanical circulatory support. Median survival for recipients of older donors was reduced by 2.6 years (12.6 vs. 15.2, P < .01). Multivariable analysis demonstrated donor age greater than 45 to be a predictor of mortality (HR 1.18 [1.05-1.33], P = .01). However, when restricting the analysis to patients who received a donor with a negative preprocurement angiogram, donor age only had a borderline association with mortality (HR 1.20 [0.98-1.46], P = .06). Older donor hearts in young recipients are associated with decreased long-term survival, however this risk is reduced in donors without atherosclerosis. The long-term hazard of this practice should be carefully weighed against the risk of waitlist mortality.

Correlation of cardiopulmonary bypass duration with acute renal failure after cardiac surgery

OBJECTIVES

Prolonged cardiopulmonary bypass (CPB) is recognized as a risk factor for acute renal failure (ARF), but the dose effect of time on bypass is unknown. We therefore examined the risk of ARF associated with increasing CPB time stratified by preoperative renal function.

METHODS

A retrospective analysis was performed on 3889 patients undergoing cardiac surgery on CPB without circulatory arrest between 2011 and 2017 excluding those with a diagnosis of dialysis-dependent renal failure and those who had an intra-aortic balloon pump. Postoperative ARF was defined as a 3-fold increase in creatinine level, creatinine level > 4 mg/dL, or requirement for dialysis. A logistic regression model was built to identify predictors of ARF and to determine the probability of ARF.

RESULTS

Postoperative ARF occurred in 72 patients (2%) overall. Of 100 patients with an estimated glomerular filtration rate <30 mL/min/1.73 m², 22% developed ARF, of which 16 required dialysis. Thirty-day mortality was 31% for those with ARF compared with <1% for those without ARF (P < .01). Risk factors for ARF included obesity (odds ratio, 3.03; P < .01), increasing preoperative creatinine level (odds ratio, 4.21; P < .01), CPB time scaled by a factor of 10 minutes (odds ratio, 1.06; P = .04), and postoperative transfusion (odds ratio, 11.94; P < .01). The adjusted probability of ARF as a function of CPB time was determined and stratified by preoperative glomerular filtration rate.

CONCLUSIONS

Increasing CPB duration is associated with postoperative ARF, particularly among those with preoperative renal impairment. For patients with an estimated glomerular filtration rate <30 mL/min/1.73 m² the risk increases exponentially with time.

Pain management and safety profiles after preoperative vs postoperative thoracic epidural insertion for bilateral lung transplantation

OBJECTIVE

Thoracic epidural analgesia provides effective pain control after lung transplantation; however, the optimal timing of placement is controversial. We sought to compare pain control and pulmonary and epidural morbidity between patients receiving preoperative vs postoperative epidurals.

METHODS

Institutional records were reviewed for patients undergoing a bilateral lung transplant via a bilateral anterior thoracotomy with transverse sternotomy incision between January 2014 and January 2017. Pain control was measured using visual analog scale pain scores (0-10). Pulmonary complications included a composite of pneumonia, prolonged intubation, and reintubation/tracheostomy.

RESULTS

Among 103 patients, 72 (70%) had an epidural placed preoperatively and 31 (30%) had an epidural placed within 72 hours posttransplant. There were no differences in the rates of cardiopulmonary bypass (3% vs 0%, P = 0.59); however, patients with a preoperative epidural were less likely to be placed on extracorporeal membrane oxygenation intraoperatively (25% vs 52%, P = 0.01). Pain control was similar at 24 hours (1.2 vs 1.7, P = 0.05); however, patients with a preoperative epidural reported lower pain scores at 48 (1.2 vs 2.1, P = 0.02) and 72 hours posttransplant (0.8 vs 1.7, P = 0.02). There were no differences in primary graft dysfunction (42% vs 56%, P = 0.28), length of mechanical ventilation (19.5 vs 24 hours, P = 0.18), or adverse pulmonary events (33% vs 52%, P = 0.12). No adverse events including epidural hematoma, paralysis, or infection resulted from epidural placement.

CONCLUSION

Preoperative thoracic epidural placement provides improved analgesia without increased morbidity following lung transplantation.

Impella Placement Guided by Echocardiography Can Be Used as a Strategy to Unload the Left Ventricle During Peripheral Venoarterial Extracorporeal Membrane Oxygenation

OBJECTIVE

At the authors' institution, before 2015, patients cannulated for peripheral venoarterial extracorporeal membrane oxygenation (VA-ECMO) did not undergo left ventricular (LV) decompression with the use of an LV vent. After 2015, the authors' institution began using the Impella device to vent the left ventricle in patients on VA-ECMO. The authors hypothesized that survival outcomes would improve in patients on VA-ECMO with the use of an Impella for LV venting.

DESIGN

Retrospective, chart based review study.

SETTING

Single center, university-based hospital.

PARTICIPANTS

All adult patients at the authors' institution who required VA-ECMO between January 2015 and May 2017.

INTERVENTION

An Impella (Abiomed, Danvers, MA) device was placed percutaneously in patients cannulated for VA-ECMO as a mechanism to provide LV venting and decompression, therefore unloading the heart.

MEASUREMENTS AND MAIN RESULTS

Manual chart review was conducted, and a survival analysis was performed. It was observed that patients on VA-ECMO in whom an Impella was implanted had improved survival and an improvement in LV function as demonstrated by echocardiography compared with patients maintained on VA-ECMO alone.

CONCLUSIONS

Patients on VA-ECMO plus Impella implantation demonstrated improved survival compared with patients treated with VA-ECMO alone. Key echocardiographic characteristics such as improved LV function after Impella placement and LV cavity size reduction during therapy may help predict those patients who may benefit most from this cannulation strategy.

Single- Versus Double-Lung Transplantation in Pulmonary Fibrosis: Impact of Age and Pulmonary Hypertension

BACKGROUND

Double-lung transplantation (DLT) has better long-term outcomes compared with single-lung transplantation (SLT) in pulmonary fibrosis. However, controversy persists about whether older patients or patients with high lung allocation scores would benefit from DLT. Moreover, the degree of pulmonary hypertension in which SLT should be avoided is unknown.

METHODS

A retrospective analysis using the United Network for Organ Sharing database was performed in all recipients of lung transplants for pulmonary fibrosis. Kaplan-Meier survival for SLT versus DLT was compared and stratified by age, allocation score, and mean pulmonary artery pressure. Cox regression and propensity-matching analyses were performed.

RESULTS

Between 1987 and 2015; 9,191 of 29,779 lung transplants were performed in pulmonary fibrosis. Ten-year survival rates were 55% for DLT and 32% for SLT (p < 0.001). When stratified by age, DLT recipients had improved survival at all age cutoffs, except age ≥70 years. In addition, DLT recipients had improved survival across all lung allocation scores (<45, ≥45, ≥60, ≥75) and all pulmonary artery pressure categories (<25, ≥25, ≥30, ≥40 mm Hg). Among DLT recipients, pulmonary artery pressure and allocation score did not affect survival. Among SLT recipients, a pressure ≥25 mm Hg did not influence survival. Conversely, patients with a pressure ≥30 mm Hg and an allocation score ≥45 had decreased survival. On Cox regression and on propensity matching, DLT had improved survival compared with SLT.

CONCLUSIONS

In pulmonary fibrosis, DLT has improved survival compared with SLT and should be considered the procedure of choice in patients younger than 70 years of age. SLT in patients with mean pulmonary artery pressure ≥30 mm Hg and an allocation score ≥45 should be discouraged.

Quantifying the learning curve for pulmonary thromboendarterectomy

BACKGROUND

Pulmonary thromboendarterectomy (PTE) is an effective treatment for chronic thromboembolic pulmonary hypertension (CTEPH), but is a technically challenging operation for cardiothoracic surgeons. Starting a new program allows an opportunity to define a learning curve for PTE.

METHODS

A retrospective case review was performed of 134 consecutive PTEs performed from 1998 to 2016 at a single institution. Outcomes were compared using either a two-tailed t-test for continuous variables or a chi-squared test for categorical variables according to experience of the program by terciles (T).

RESULTS

The 30-day mortality was 3.7%. The mean length of hospital stay, length of ICU stay, and duration on a ventilator were 12.6 days, 4.6 days, and 2.0 days, respectively. The mean decrease in systolic pulmonary artery pressure (sPAP) was 41.3 mmHg. Patients with Jamieson type 2 disease had a greater change in mean sPAP than those with type 3 disease (p = 0.039). The mean cardiopulmonary bypass time was 180 min (T1-198 min, T3-159 min, p = <0.001), and the mean circulatory arrest time was 37 min (T1-44 min, T3-31 min, p < 0.001). Plotting circulatory arrest times as a running sum compared to the mean demonstrated 2 inflection points, the first at 22 cases and the second at 95 cases.

CONCLUSIONS

PTE is a challenging procedure to learn, and good outcomes are a result of a multi-disciplinary effort to optimize case selection, operative performance, and postoperative care. Approximately 20 cases are needed to become proficient in PTE, and nearly 100 cases are required for more efficient clearing of obstructed pulmonary arteries.

Bridge to transplant or recovery in cardiogenic shock in a developing country

Background Durable mechanical support devices are prohibitively expensive in our health system and may be unsuitable for critically ill patients. CentriMag is an alternative bridge to transplantation or recovery. Methods We retrospectively reviewed 28 patients (23 males) aged 13-60 years who received CentriMag support. The etiology was ischemic in 13 (46%), dilated cardiomyopathy in 8 (29%), and others in 7 (25%). All patients were in Interagency Registry for Mechanically Assisted Circulatory Support class I, and 27 (96%) had multiorgan failure; 2 (7%) were post-cardiotomy and 12 (43%) had a previous cardiac arrest (mean arrest time 21 ± 17 min). Results Thirty-day post-implant survival was 79% (22 patients). Twenty (71%) patients were successfully bridged to transplantation or recovery. The mean support time was 40 days; 12 (43%) patients had >4-weeks' support (longest was 292 days). Eight (29%) patients died on support. Complications included bleeding in 10 (36%) cases, immediate stroke in 4 (14%), and dialysis in 8 (29%). There was no stroke during subsequent support. Eighteen (64%) patients underwent transplantation, and 17 of them were discharged. Two (7%) patients recovered and were discharged. Two-year survival was 62% ± 10%. Mean follow-up was 21 months (total follow-up 579 months). Two (7%) patients died during follow-up. All survivors were in New York Heart Association class I. Conclusions CentriMag is useful for medium-term support for cardiogenic shock in a developing country. Support for >4 weeks is feasible. The stroke rate is low during support. The major drawback is prolonged intensive care unit stay.

Cardiac Surgery in Patients With Body Mass Index of 50 or Greater

BACKGROUND

The seemingly inexorable rise in obesity worldwide is creating a new set of challenges for healthcare providers. Demand for cardiac surgical intervention among patients at extreme levels of obesity (body mass index [BMI] > or = 50) is increasing; however, the risks, benefits, and resources required to meet this need have not been established.

METHODS

Between 1993 and 2004, 57 patients with a BMI of 50 or more underwent cardiac surgical procedures at our institution. The mean BMI was 54 +/- 4, weight range was 124 to 226 kg. The mean age of the study group was 55 +/- 12 years, and comorbidities included diabetes mellitus in 29 (51%), hypertension in 40 (70%), hyperlipidemia in 22 (39%), and obstructive sleep apnea in 16 (28%).

RESULTS

The operative mortality was 7% (4 patients). Eleven patients (20%) required prolonged intubation (more than 24 hours), and mean intensive care unit stay was 5 +/- 9 days. Wound complications requiring surgery occurred in 3 (5%). Survival at 1 and 5 years was 93% +/- 4% and 76 +/- 8%, respectively. By univariate analysis, age and endocarditis were associated with long-term mortality and major perioperative complications. As a dichotomous variable, BMI greater than 54 was a significant predictor of renal failure and prolonged mechanical ventilation.

CONCLUSIONS

Cardiac surgery in the patient with a BMI of 50 or greater is associated with significant resource utilization, including prolonged intensive care unit and hospital stay, with prolonged intubation and wound complications relatively common.