Faculty Bibliography

Objective: There are 3 cardiothoracic surgery (CTS) training paradigms-general surgery residency followed by CTS residency, 4 years of general surgery +3 years of CTS residency (4 + 3), and an integrated 6-year pathway (I-6). Studies to assess additional training requirements between paradigms have yet to be well described.
Method(s): An anonymous online survey aimed at collecting demographics, training pathway data, and need for additional training from CTS graduates within the past 5 years (2012 to 2017) was developed. An automated online email list was generated and sent out, with 2 reminder emails resent for nonresponders. The survey was open for a 2-month period.
Result(s): Four hundred seventy- seven emails were sent and received with a 20% response rate (95/477). Eighty percent (76/95) were male, mean age 39.4 years old (range 33 to 50). Eighty-one percent (77/95) completed a traditional training pathway, 7.4% (7/95) a 4 + 3, and 11.6% (11/95) an I-6. Twenty-seven percent (26/95) completed additional training-7.7% (2/26) robotics, 19.2% (5/26) additional thoracic, 3.8% (1/26) additional cardiac, 11.5% (3/26) congenital, 42.3% (11/26) transplant/mechanical circulatory support, and 15.4% (4/26) aortic/endovascular. Of those respondents who completed additional training, 73.0% (19/26) had completed a traditional training pathway, 3.8% (1/26) a 4 + 3, and 7.7% (2/26) an I-6. Twenty-four percent (23/95) completed >=10 years of postgraduate training.
Conclusion(s): There are 3 distinct CTS training pathways offering varying lengths of training and specialization. Among survey respondents, 27% completed additional training after completing CTS residency and 24% of respondents took 10 or more years to complete their training

Study: The Impella (Abiomed, Danvers, MA) ventricular support system is a family of temporary mechanical circulatory support devices designed to treat patients with cardiogenic shock. These devices include the percutaneously implanted 2.5/CP and the surgically implanted 5.0/LD. Data to assess adverse outcomes and help guide decision-making between Impella CP and 5.0/LD devices is limited. The purpose of this study was to compare the characteristics and clinical outcomes between Impella CP and 5.0/LD at our institution.
Method(s): From December 1, 2014 to October 31, 2019 a total of 117 patients underwent Impella implantation regardless of indication or device type. Of these, 82 patients were supported for greater than 24-hour duration. Baseline patient characteristics and outcomes were reviewed retrospectively. Groups were stratified based on either initial Impella CP or 5.0/LD placement and their clinical outcomes compared.
Result(s): Impella CP was implanted in 56 patients (median age: 60.5 years, male 71.4%) and Impella 5.0/LD (median age: 65.5 years, male 84.6%) were implanted in 26 patients. Regardless of the indication for Impella placement, 24 patients with Impella CP required additional mechanical support and were upgraded to either Impella 5.0/LD or extracorporeal membrane oxygenation (ECMO) (p=0.005). Patients with Impella CP had increased incidence of hemolysis defined as the presence of gross hematuria and elevated lactated dehydrogenase (Table 1). Patients with Impella 5.0/LD were more likely to survive from Impella and survive to discharge. Data from this study suggests that Impella 5.0/LD may have a more favorable device-specific adverse event profile compared to Impella CP

Study: Despite advances in design and hemocompatibility, pump thrombosis remains a significant cause of morbidity for patients implanted with durable left ventricular assist devices (LVAD). Pharmacologic fibrinolysis may be preferred as initial therapy because it obviates a surgical procedure. Yet, it historically has been associated with a significant risk of secondary intracerebral hemorrhage (ICH).
Method(s): We implemented a novel protocol to treat HVAD pump thrombosis and minimize risk of ICH that consisted of the following: initiation of a non-titrating heparin infusion at 500 units/hr; normalization of international normalized ratio (INR) by giving a flat dose of 1,000 units of four-factor prothrombin complex concentration (4F-PCC); and administration of alteplase as a 10 mg bolus followed by 40 mg given over 3 hours.
Result(s): Two patients underwent treatment with the above protocol for presumed HVAD pump thrombosis based on clinical signs of hemolysis and elevations of power on log-file analysis. One patient was 2 months from HVAD implant and the other 13 months. Both patients had subtherapeutic INR in the preceding weeks. Following administration of alteplase, log-file analysis demonstrated immediate resolution of power elevations (Fig. 1). Both patients had a subsequent rise in power requiring repeat alteplase dosing. No bleeding or thrombotic events occurred with treatment. One patient underwent heart transplant a month after treatment and is doing well; the second patient is stable on HVAD support 4 months following alteplase. Combining 4F-PCC to temporarily normalize the INR with repeat dosing of alteplase was effective at resolving HVAD pump thrombosis without bleeding complications and should be investigated further

A morbidly obese middle aged woman in her 40's presented to another hospital with methicillin resistant staphylococcus aureus pneumonia and subsequently developed severe acute respiratory distress syndrome. Her oxygenation demonstrated no improvement with low tidal volume ventilation, paralysis, or prostagladin therapy. She was unable to be manually proned secondary to her habitus. She was subsequently transferred to our facility, where she was initiated on VV-ECMO. Maximal flow through the ECMO circuit was inadequate for oxygenation given significant systemic shunt through her native lungs. In order to optimize lung protective ventilation and treat ARDS, we used an automated kinetic system (Rotoprone Therapy System) to prone the patient. To our knowledge, this is the first description in the literature of using an automated proning system with an ECMO circuit in place. This report describes the technique we used to safely perform axial rotations for two days with fewer providers required than manual proning.

BACKGROUND:The Impella (Abiomed) ventricular support system is a family of temporary mechanical circulatory support (MCS) devices used to treat patients with cardiogenic shock, acute cardiogenic decompensation, and for high-risk percutaneous or surgical revascularization. These devices include the percutaneously implanted 2.5/cardiac power (CP) and the surgically implanted 5.0/left direct (LD). Despite the beneficial effects and increased usage of these devices, data to assess adverse outcomes and guide clinician decision-making between the Impella CP and 5.0/LD are limited. METHODS:This is a retrospective analysis of 91 consecutive patients who required at least 24 h of Impella support, from January 1, 2015 to December 31, 2019. Groups were stratified based on either initial Impella CP or 5.0/LD placement. Clinical outcomes and in-hospital complications were compared. RESULTS:Impella CP was implanted in 66 patients (mean age: 61 ± 15 years, male 71.2%) and Impella 5.0/LD was implanted in 25 patients (mean age: 62 ± 9 years, male 84.0%). There was greater stability of device position (p = .033), less incidence of hemolysis (p < .001), and less frequent need for additional MCS (p = .001) in patients implanted with the Impella 5.0/LD compared with Impella CP in this study cohort. Patients with Impella 5.0/LD were more likely to survive from Impella and survive to discharge. CONCLUSIONS:This study suggests that for patients who require temporary MCS for more than 24 h, the Impella 5.0/LD may have a more favorable device-specific adverse profile compared with the Impella CP.

Over the past several decades, the operation of choice for end-stage lung disease secondary to severe pulmonary hypertension (PH) has shifted from heart-lung transplantation (HLT) to bilateral lung transplantation (BLT). This change has maintained excellent long-term outcomes and is appropriate for the majority of patients presenting with end-stage disease in need of transplantation. However, a distinct subset of patients with severe PH have an excessive early mortality within 90 days of transplantation. Based on the different causes of this early mortality compared to BLT recipients with other indications, right heart failure and refractory primary graft dysfunction (PGD) appear to play a significant role. It is therefore critical to identify this subset of patient during their evaluation for transplant. This distinction would allow specific patient referral for HLT, which may mitigate those causes of early mortality. Similarly, there is a subgroup of BLT recipients for severe PH that fail to recover right ventricular function, with suboptimal long-term functional status that is independent of early survival. Identification and referral for HLT of these patients may also be important. In this manuscript, we describe our institutional approach and consideration for the risks of early mortality from right heart failure and PGD, as well failure of right ventricular recovery long-term. The described evaluation is used to ascertain those patients with severe PH who may benefit from a HLT over BLT.

BACKGROUND:Increased utilization of hepatitis C virus (HCV)-positive donors has increased transplantation rates. However, high levels of viremia have been documented in recipients of viremic donors. There is a knowledge gap in how transient viremia may impact acute cellular rejections (ACRs). METHODS:In this study, 50 subjects received hearts from either viremic or non-viremic donors. The recipients of viremic donors were classified as nucleic acid amplification testing (NAT)+ group, and the remaining were classified as NAT-. All patients were monitored for viremia levels. Endomyocardial biopsies were performed through 180 days, evaluating the incidence of ACRs. RESULTS:A total of 50 HCV-naive recipients received hearts between 2018 and 2019. A total of 22 patients (44%) who received transplants from viremic donors developed viremia at a mean period of 7.2 ± 0.2 days. At that time, glecaprevir/pibrentasvir was initiated. In the viremia period (<56 days), 14 of 22 NAT+ recipients (64%) had ACR vs 5 of 28 NAT- group (18%) (p = 0.001). Through 180 days, 17 of 22 NAT+ recipients (77%) had a repeat rejection biopsy vs 12 of 28 NAT- recipients (43%) (p = 0.02). NAT+ biopsies demonstrated disparity of ACR distribution: negative, low-grade, and high-grade ACR in 84%, 12%, and 4%, respectively, vs 96%, 3%, and 1%, respectively, in the NAT- group (p = 0.03). The median time to first event was 26 (interquartile range [IQR]: 8-45) in the NAT+ group vs 65 (IQR: 44-84) days in the NAT-. Time to first event risk model revealed that NAT+ recipients had a significantly higher rate of ACR occurrences, adjusting for demographics (p = 0.004). CONCLUSIONS:Transient levels of viremia contributed to higher rates and severity of ACRs. Further investigation into the mechanisms of early immune activation in NAT+ recipients is required.

Glucose 6-phosphate dehydrogenase (G6PD) deficiency facilitates human coronavirus infection due to glutathione depletion. G6PD deficiency may especially predispose to hemolysis upon coronavirus disease-2019 (COVID-19) infection when employing pro-oxidant therapy. However, glutathione depletion is reversible by N-acetylcysteine (NAC) administration. We describe a severe case of COVID-19 infection in a G6PD-deficient patient treated with hydroxychloroquine who benefited from intravenous (IV) NAC beyond reversal of hemolysis. NAC blocked hemolysis and elevation of liver enzymes, C-reactive protein (CRP), and ferritin and allowed removal from respirator and veno-venous extracorporeal membrane oxygenator and full recovery of the G6PD-deficient patient. NAC was also administered to 9 additional respirator-dependent COVID-19-infected patients without G6PD deficiency. NAC elicited clinical improvement and markedly reduced CRP in all patients and ferritin in 9/10 patients. NAC mechanism of action may involve the blockade of viral infection and the ensuing cytokine storm that warrant follow-up confirmatory studies in the setting controlled clinical trials.

PURPOSE/OBJECTIVE:The right ventricular outflow tract (RVOT) velocity time integral (VTI), an echocardiographic measure of stroke distance, correlates with cardiac index. We sought to determine the prognostic significance of low RVOT VTI on clinical outcomes among patients with acute pulmonary embolism (PE). MATERIALS AND METHODS/METHODS:We conducted a retrospective review of echocardiograms on Pulmonary Embolism Response Team (PERT) activations at our institution. The main outcome was a composite of death, cardiac arrest, or hemodynamic deterioration. RESULTS:Of 188 patients, 30 met the combined outcome (16%) and had significantly lower RVOT VTI measurements (9.0 cm v 13.4 cm, p < 0.0001). The AUC for RVOT VTI at a cutoff of 10 cm was 0.78 (95% CI 0.67-0.90) with a sensitivity, specificity, negative predictive value, and positive predictive value of 0.72, 0.81, 0.94, and 0.42, respectively. Fifty-two patients of the cohort were classified as intermediate-high-risk PE and 21% of those met the combined outcome. RVOT VTI was lower among outcome positive patients (7.3 cm v 10.7 cm, p = 0.02). CONCLUSIONS:Low RVOT VTI is associated with poor clinical outcomes among patients with acute PE.

We conducted a retrospective review of thoracic transplant recipients (22 heart and 16 lung transplant recipients) prospectively enrolled in a single-center observational study of HCV NAT+ organ transplantation in HCV NAT- recipients. All recipients were treated with 8 weeks of glecaprevir-pibrentasvir (GP) for HCV viremia in addition to standard triple immunosuppression post-transplant. Thoracic transplant recipients of HCV NAT- organs were used as a control (24 heart and 22 lung transplant recipients). Our primary outcome was to assess the effect of GP on tacrolimus dose requirements. Secondary objectives included assessing drug interactions with common post-transplant medications, adverse effects, and the need to hold or discontinue GP therapy. The median tacrolimus concentration-to-dose (CDR) in the cohort was 184 (99-260) during GP therapy and 154 (78-304) over the first month after GP (p=0.79). Trends in median tacrolimus CDR were similar on a per-week basis and per-patient basis. In three instances, concomitant posaconazole and GP led to hyperbilirubinemia and interruption of posaconazole. GP therapy was held in one heart transplant recipient, and discontinued in another, due to unresolving hyperbilirubinemia. Utilization of GP to treat HCV viremia post-thoracic transplant is feasible and safe, but requires modifications to post-transplant pharmacotherapy and careful monitoring for adverse effects.