Faculty Bibliography

BACKGROUND:The onset of the coronavirus disease 2019 (COVID-19) pandemic has forced our cardiac surgery program and hospital to enact drastic measures that has forced us to change how we care for cardiac surgery patients, assist with COVID-19 care, and enable support for the hospital in terms of physical resources, providers, and resident training. METHODS:In this review, we review the cardiovascular manifestations of COVID-19 and describe our system-wide adaptations to the pandemic, including the use of telemedicine, how a severe reduction in operative volume affected our program, the process of redeployment of staff, repurposing of residents into specific task teams, the creation of operation room intensive care units, and the challenges that we faced in this process. RESULTS:We offer a revised set of definitions of surgical priority during this pandemic and how this was applied to our system, followed by specific considerations in coronary/valve, aortic, heart failure and transplant surgery. Finally, we outline a path forward for cardiac surgery for the near future. CONCLUSIONS:We recognize that individual programs around the world will eventually face COVID-19 with varying levels of infection burden and different resources, and we hope this document can assist programs to plan for the future.

Intensive care unit (ICU)-acquired weakness is a common and serious sequela of critical illness. There is a growing body of evidence supporting the use of early mobilization in the ICU to mitigate this adverse effect. Recent data suggest that such a strategy may be feasible in patients with the most severe forms of cardiopulmonary failure-those requiring temporary mechanical circulatory support (TCS) or extracorporeal life support (ECLS). Both the modality of mechanical support and patient-specific characteristics must be taken into consideration when determining the appropriateness of an early mobilization strategy. The purpose of this review is to explore the current understanding of and evidence for mobilization and rehabilitation of patients receiving TCS or ECLS, including the identification of factors that may predict greater success for early mobilization and potential risks and contraindications to active physical therapy. While it is not yet known which of these patients are most likely to benefit from physical rehabilitation, a common theme is the importance of an interprofessional team approach to ensure patient safety and maximize the likelihood of successful mobilization.

OBJECTIVES:Right heart failure after left ventricular assist device (LVAD) implantation is associated with significant morbidity and mortality. A new generation of percutaneous right ventricular assist devices (RVADs) may mitigate the need for invasive surgical RVAD implantation. The purpose of this study was to evaluate the safety and efficacy of the Protek Duo (TandemLife, Pittsburgh, PA, USA) RVAD in patients who developed severe acute right heart failure in the intensive care unit after LVAD implantation. METHODS:This was a retrospective cohort study of 27 patients who received a Protek Duo after LVAD implantation from January 2016 to March 2019 at our centre. The primary outcome of interest was survival to hospital discharge. Secondary outcomes included procedural success, device-related complications and conversion to a surgical RVAD. RESULTS:The median age of patients was 63 years (interquartile range 58-71), 78% were men and 78% were Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) profile 1 or 2. Patients were on a median of 2 inotropes and 2 pressors prior to Protek Duo insertion. The device successfully implanted on the first attempt in all patients a median of 1 day (interquartile range 1-2) after LVAD implantation and the median duration of support was 11 days (interquartile range 7-16). Device weaning occurred in 86% of patients, with 15% in-hospital mortality. Major complications related to the device included new moderate-to-severe tricuspid regurgitation (36%), haemolysis (14%) and cannula migration (7%). Three patients (11%) required conversion to surgical RVAD. Overall survival to 1 year was 81%. CONCLUSIONS:The use of the Protek Duo as a percutaneous RVAD is a safe and feasible treatment for patients who develop acute right heart failure after LVAD implantation.

OBJECTIVE:In 2011, a multidisciplinary hypertrophic cardiomyopathy (HCM) program with a dedicated myectomy surgeon was implemented at our institution. We hypothesized that a dedicated approach allows better identification and management of mitral regurgitation (MR) during septal myectomy (SM) for obstructive HCM with significant mitral regurgitation. METHODS:Between 2006 and 2018, 181 patients had SM at our institution. This study consists of 53 patients with preoperative moderate or greater MR associated with systolic anterior motion who underwent isolated SM with or without mitral intervention. Patients were divided into those who underwent SM by a dedicated myectomy surgeon (group D, n = 31) or by a non-dedicated surgeon (group ND, n = 22). Primary outcome of interest was rate of mitral valve replacement (MVR) at SM. Secondary outcomes include in-hospital mortality, need for permanent pacemaker, mitral valve reoperation, and residual MR and left ventricular outflow tract gradient on postoperative echocardiography. RESULTS:12 patients (55%) had a concomitant MVR during septal myectomy in group ND compared to 2 patients (6%) in group D (p < 0.01). Among patients who did not undergo MVR, patients in group D less commonly had residual MR than patients in ND after SM (p < 0.01). Group D had 100% survival with NYHA class I in 94% patients at follow-up visit (p = 0.01). Reoperation for MVR was required in four patients in group ND vs. none in group D (p < 0.01). CONCLUSIONS:A dedicated surgeon is able to spare the mitral valve in patients undergoing SM. This study emphasizes the importance of surgical expertise in this cohort.

BACKGROUND:The onset of the coronavirus disease 2019 (COVID-19) pandemic has forced our cardiac surgery program and hospital to enact drastic measures that has forced us to change how we care for cardiac surgery patients, assist with COVID-19 care, and enable support for the hospital in terms of physical resources, providers, and resident training. METHODS:In this review, we review the cardiovascular manifestations of COVID-19 and describe our system-wide adaptations to the pandemic, including the use of telemedicine, how a severe reduction in operative volume affected our program, the process of redeployment of staff, repurposing of residents into specific task teams, the creation of operation room intensive care units, and the challenges that we faced in this process. RESULTS:We offer a revised set of definitions of surgical priority during this pandemic and how this was applied to our system, followed by specific considerations in coronary/valve, aortic, heart failure and transplant surgery. Finally, we outline a path forward for cardiac surgery for the near future. CONCLUSIONS:We recognize that individual programs around the world will eventually face COVID-19 with varying levels of infection burden and different resources, and we hope this document can assist programs to plan for the future.

BACKGROUND:Extracorporeal membrane oxygenation (ECMO) as a bridge to lung transplantation (BTT) has become a critical component of caring for patients with end-stage lung disease. This study examined outcomes of patients who received ECMO as a BTT. METHODS:Statistical analysis was performed on data gathered retrospectively from the electronic medical records of adult patients who received ECMO as BTT at Columbia University Medical Center from April 2009 through July 2018. RESULTS:A total of 121 adult patients were placed on ECMO as BTT, and 70 patients (59%) were successfully bridged to lung transplantation. Simplified Acute Physiology Score II, unplanned endotracheal intubation, renal replacement therapy, and cerebrovascular accident were identified as independent predictors of unsuccessful BTT. Ambulation was the only independent predictor of successful BTT (odds ratio, 7.579; 95% confidence interval, 2.158 to 26.615; p = 0.002). Among the 64 patients (91%) who survived to hospital discharge, survival was 88% at 1 year and 83% at 3 years. Propensity matching between BTT and non-BTT lung transplant recipients did not show a significant difference in survival (log-rank = 0.53) despite significant differences in the lung allocation score (median, 92.2 [interquartile range, 89.0 to 94.2] vs 49.6 [interquartile range, 40.6 to 72.3], p < 0.01). CONCLUSIONS:ECMO can be used successfully to bridge patients with end-stage lung disease to lung transplantation. When implemented by an experienced team with adherence to stringent protocols and patient selection, outcomes in BTT patients were comparable to patients who did not receive pretransplant support.

BACKGROUND:Venoarterial extracorporeal membrane oxygenation (VA-ECMO) can be life-saving in refractory cardiogenic shock but carries a risk of neurologic complications such as stroke and hemorrhage. As little is known about the effects of different peripheral VA-ECMO cannulation sites on cerebral blood flow (CBF), transcranial Doppler (TCD) was used to determine whether the cannulation site affects CBF. METHODS:Thirty-seven patients receiving VA-ECMO for cardiogenic shock via axillary or femoral artery cannulation were prospectively enrolled. Measured bilateral middle cerebral artery (MCA), mean flow velocities (MFV), and pulsatility indices (PI) were the primary outcomes and adverse neurologic events were secondary outcomes. RESULTS:The median age was 58 years (IQR 51-66) with 26 (70%) males. Median VA-ECMO flow was 3.8 L/min (IQR 3.2-4.9) with mean arterial pressures of 80 mm Hg (IQR 75-86). Nineteen patients received right axillary artery cannulation while 18 underwent femoral cannulation. Compared with the femoral group, MFV was higher in the axillary group in the right MCA (46 cm/s [IQR 26-57] vs 27 [17-36], P = 0.03) and left (43 [IQR 35-60] vs 29 cm/s [16-48], P = 0.05). Axillary PI was significantly lower compared with the femoral group (right: 0.48 cm/s [0.25-0.65] vs 0.83 [0.66-0.93], P = 0.02; left: 0.41 cm/s [0.29-0.63] vs 1.02 [0.7-1.3], P = 0.004). One axillary patient experienced a stroke with deficits. CONCLUSIONS:TCD appears to be an effective tool for indirect monitoring of CBF in patients with ECMO with limited pulsatility. Axillary artery cannulation seems to provide higher cerebral flow rates without any difference in neurologic outcomes. Future studies may incorporate TCD into regulating ECMO flows to achieve physiologic CBF.

The number of available donor organs limits lung transplantation, the only lifesaving therapy for the increasing population of patients with end-stage lung disease. A prevalent etiology of injury that renders lungs unacceptable for transplantation is gastric aspiration, a deleterious insult to the pulmonary epithelium. Currently, severely damaged donor lungs cannot be salvaged with existing devices or methods. Here we report the regeneration of severely damaged lungs repaired to meet transplantation criteria by utilizing an interventional cross-circulation platform in a clinically relevant swine model of gastric aspiration injury. Enabled by cross-circulation with a living swine, prolonged extracorporeal support of damaged lungs results in significant improvements in lung function, cellular regeneration, and the development of diagnostic tools for non-invasive organ evaluation and repair. We therefore propose that the use of an interventional cross-circulation platform could enable recovery of otherwise unsalvageable lungs and thus expand the donor organ pool.

Background Cardiogenic shock ( CS ) following acute myocardial infarction ( AMI ) portends a poor prognosis. Both venoarterial extracorporeal membrane oxygenation ( VA - ECMO ) and a percutaneous ventricular assist device ( pVAD ) provide hemodynamic support for patients with CS, but little is known about the best device for this population. We sought to compare outcomes of AMI patients treated with these devices. Methods and Results Consecutive patients with CS following AMI from April 2015 to March 2017 were enrolled prospectively if they received either device for AMI -related CS . If patients received both devices, they were analyzed according to the first used. The primary outcome was all-cause mortality. In total, 51 patients received VA - ECMO or pVAD following AMI ; 20 received VA - ECMO, and 31 received pVAD . The mean age was 62.1±10.1 years, and 39 (76.5%) were men. Twenty-four (47.1%) patients were ultimately supported by both devices simultaneously (20 pVAD -first, 4 VA - ECMO -first). Patients treated with pVAD or VA - ECMO were similar in baseline characteristics at initial device insertion except that the latter were on more vasopressors and were more likely to have an intra-aortic balloon pump. Seventeen (33.3%) had recent cardiopulmonary resuscitation, mean lactate was 4.86±3.96 mmol/L, and mean cardiac index was 1.70±0.42 L/min per m². Of the 28 (54.9%) patients surviving to discharge, 11 had received VA - ECMO first and 17 had pVAD first ( P=0.99). Survival at 1 and 2 years did not differ significantly between device groups ( P=0.42). Conclusions Following AMI -related CS , pVAD - and VA - ECMO -treated patients had similar outcomes. The use of both devices simultaneously was common, with almost half of patients in persistent CS after first device deployment.

Although low birth weight is a known risk factor for mortality in congenital heart lesions and may consequently delay surgical repair, outcomes in low-weight neonates undergoing the arterial switch operation (ASO) have not been well described. Our objective was to assess the safety of this procedure in infants weighing ≤2.5 kg at the time of surgery. We retrospectively analyzed outcomes for all neonates undergoing the ASO at our institution from 2005 to 2015. Our primary outcome of interest was major morbidity or operative mortality, assessed as a composite outcome. From 2005 to 2015, 217 neonates underwent the ASO, with 31 (14%) weighing ≤2.5 kg at the date of surgery, and 8 weighing <2.0 kg. Neonates weighing ≤2.5 kg were more likely to be premature than those weighing >2.5 kg, but there was no difference in the age at operation between these groups. Overall, 32 infants experienced a major morbidity or mortality, including 37.5% (n = 3) weighing <2.0 kg, 8.7% (n = 2) weighing 2.0-2.5 kg, and 14.5% (n = 7) weighing >2.5 kg (P = 0.141). One infant weighing <2.0 kg (1.1 kg) and 4 infants weighing >2.5 kg died. In multivariable models, odds of major morbidity or mortality were significantly higher for infants weighing <2 kg compared with infants weighing >2.5 kg (odds ratio 3.93, 95% confidence interval 1.04-14.85, P = 0.044), but there was no difference between infants weighing 2.0-2.5 kg and those weighing >2.5 kg (P = 0.225). The ASO can be performed safely in 2.0- to 2.5-kg neonates and yields results comparable with higher weight infants. Imposed delays for corrective surgery may not be necessary for these low-weight infants with transposition of the great arteries.