Cardiothoracic Surgery Interviews and Selection in a Pandemic Era - Lessons to Learn.

INTRODUCTION: Candidate selection for cardiothoracic surgery (CTS) training programs is challenging. The recent pandemic has impacted a program's ability to meet matriculants in-person. We hypothesized that a central venue at the CTS annual meeting could prove as a favorable supplement for programs and applicants. METHODS: Surveys were sent to adult cardiothoracic and congenital cardiac surgery training program directors (PD) and department chairs or division chiefs. Separately, surveys were sent to applicants from the 2018 through 2023 electronic residency application service match process. RESULTS: A total of 166 individuals (PDs and department chairs or division chiefs) were contacted. This represented 94 unique programs, and 45 programs responded. The majority of these programs (88.9%) felt that social gatherings were valuable in evaluating applicants and 86.7% would be interested in a social event at an Society of Thoracic Surgery annual meeting. 54% of applicants did not get an accurate impression of the programs to inform their rank list through virtual interviews, 70% would not be able to accept the same number of interviews in-person versus virtual, and 94% would be interested in attending an annual conference to meet program faculty. CONCLUSIONS: A centralized in-person interview event allows for fiscal and scheduling efficiencies, while creating an opportunity for an equitable exchange between potential candidates and PDs in an efficient manner. Such an event would cost a fraction of what our profession has been incurring, could diversify our workforce, would create early mentoring linkages, and perhaps remodel the way we select trainees.

Ethical and Equity Guidance for Transplant Programs Considering Thoracoabdominal Normothermic Regional Perfusion (TA-NRP) for Procurement of Hearts.

Donation after circulatory determination of death (DCDD) is an accepted practice in the United States, but heart procurement under these circumstances has been debated. Although the practice is experiencing a resurgence due to the recently completed trials using ex vivo perfusion systems, interest in thoracoabdominal normothermic regional perfusion (TA-NRP), wherein the organs are reanimated in situ prior to procurement, has raised many ethical questions. We outline practical, ethical, and equity considerations to ensure transplant programs make well-informed decisions about TA-NRP. We present a multidisciplinary analysis of the relevant ethical issues arising from DCDD-NRP heart procurement, including application of the Dead Donor Rule and the Uniform Definition of Death Act, and provide recommendations to facilitate ethical analysis and input from all interested parties. We also recommend informed consent, as distinct from typical "authorization," for cadaveric organ donation using TA-NRP.

Challenging Paradigm Limits of Retrograde Cerebral Perfusion During Lower Body Circulatory Arrest.

INTRODUCTION: Retrograde cerebral perfusion (RCP) is a safe and effective technique to augment cerebral protection during lower body circulatory arrest in patients undergoing elective hemiarch replacement. However, recommendations guiding optimal temperature, flow rate, and perfusion pressure are outdated and potentially overly limiting. We report our experience using RCP for elective hemiarch replacement with parameters that challenge the currently accepted paradigm. METHODS: This was a single-center, retrospective analysis of 319 adult patients who underwent elective hemiarch replacement between February 2010 and 2021 using hypothermic lower body circulatory arrest with RCP alone, RCP followed by antegrade cerebral perfusion (ACP), or ACP alone. Flow rates were adjusted to maintain cerebral perfusion pressure between 30 and 50 mm Hg for RCP and between 40 and 60 mm Hg for ACP. RESULTS: RCP was used in 22.6% (n = 72) of cases, whereas ACP alone was performed in 77.4% (n = 247) of cases. Baseline patient characteristics were similar between groups. Patients undergoing RCP demonstrated shorter cross-clamp time (97.0 min versus 100.0 min, P = 0.034) and shorter lower body circulatory arrest time (7.0 min versus 10.0 min, P < 0.0001) compared with ACP alone. Nadir bladder temperature was equivalent between groups (27.3°C versus 27.5°C, P = 0.752). There were no significant differences in postoperative complications, neurologic outcomes, or mortality. CONCLUSIONS: Moderate hypothermic lower body circulatory arrest combined with RCP at target perfusion pressures of 30-50 mm Hg in patients undergoing elective hemiarch replacement results in equivalent neurologic outcomes and overall morbidity to cases using ACP alone. These results challenge the currently accepted paradigm for RCP, which typically uses deep hypothermia while keeping perfusion pressures below 25 mm Hg.

Impella 5.5 support before, during, and after surgical ventricular septal defect repair: A bridge continuum.

INTRODUCTION: Post-infarction ventricular septal defect formation remains a formidable mechanical complication of acute myocardial infarction associated with increased morbidity and mortality. CASE PRESENTATION: We describe the case of a 72-year-old male who was admitted with post-myocardial infarction ventricular septal defect and cardiogenic shock. DISCUSSION: Impella 5.5 with SmartAssist as temporary left ventricular assist device provided sufficient support throughout multiple bridging episodes including failed percutaneous repair and subsequent definitive surgical repair. Contemporary management of post-infarction ventricular septal defect is discussed.

New insights into resting and exertional right ventricular performance in the healthy heart through real-time pressure-volume analysis.

KEY POINTS: Despite growing interest in right ventricular form and function in diseased states, there is a paucity of data regarding characteristics of right ventricular function - namely contractile and lusitropic reserve, as well as ventricular-arterial coupling, in the healthy heart during rest, as well as submaximal and peak exercise. Pressure-volume analysis of the right ventricle, during invasive cardiopulmonary exercise testing, demonstrates that that the right heart has enormous contractile reserve, with a three- or fourfold increase in all metrics of contractility, as well as myocardial energy production and utilization. The healthy right ventricle also demonstrates marked augmentation in lusitropy, indicating that diastolic filling of the right heart is not passive. Rather, the right ventricle actively contributes to venous return during exercise, along with the muscle pump. Ventricular-arterial coupling is preserved during submaximal and peak exercise in the healthy heart. ABSTRACT: Knowledge of right ventricular (RV) function has lagged behind that of the left ventricle and historically, the RV has even been referred to as a 'passive conduit' of lesser importance than its left-sided counterpart. Pressure-volume (PV) analysis is the gold standard metric of assessing ventricular performance. We recruited nine healthy sedentary individuals free of any cardiopulmonary disease (42 ± 12 years, 78 ± 11 kg), who completed invasive cardiopulmonary exercise testing during upright ergometry, while using conductance catheters inserted into the RV to generate real-time PV loops. Data were obtained at rest, two submaximal levels of exercise below ventilatory threshold, to simulate real-world scenarios/activities of daily living, and maximal effort. Breath-by-breath oxygen uptake was determined by indirect calorimetry. During submaximal and peak exercise, there were significant increases in all metrics of systolic function by three- to fourfold, including cardiac output, preload recruitable stroke work, and maximum rate of pressure change in the ventricle (dP/dtmax ), as well as energy utilization as determined by stroke work and pressure-volume area. Similarly, the RV demonstrated a significant, threefold increase in lusitropic reserve throughout exercise. Ventricular-arterial coupling, defined by the quotient of end-systolic elastance and effective arterial elastance, was preserved throughout all stages of exercise. Maximal pressures increased significantly during exercise, while end-diastolic volumes were essentially unchanged. Overall, these findings demonstrate that the healthy RV is not merely a passive conduit, but actively participates in cardiopulmonary performance during exercise by accessing an enormous amount of contractile and lusitropic reserve, ensuring that VA coupling is preserved throughout all stages of exercise.

Clinical predictors of in-hospital mortality in venoarterial extracorporeal membrane oxygenation.

INTRODUCTION: Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is utilized as a life-saving procedure and bridge to myocardial recovery for patients in refractory cardiogenic shock. Despite technical advancements, VA-ECMO retains high mortality. This study aims to identify the clinical predictors of in-hospital mortality after VA-ECMO to improve risk stratification for this tenuous patient population. METHODS: The REgistry for Cardiogenic Shock: Utility and Efficacy of Device Therapy database is a multicenter, observational registry of ECMO patients. From 2013 to 2018, 789 patients underwent VA-ECMO. Bivariate analysis was performed on more than 300 variables regarding their association with in-hospital mortality. Logistic regression analyses were performed with variables chosen based upon clinical and statistical significance in the bivariate analysis. Tests were considered significant at a two-sided P < .05. RESULTS: Although 63.5% patients were successfully weaned from VA-ECMO, in-hospital mortality was 57.9%. Nonsurvivors were older (P < .0001), had higher body mass index (P = .01), higher rates of hypertension (P = .02), coronary artery disease (P = .02), chronic obstructive pulmonary disease (P = .02), chronic liver disease (P = .008), percutaneous coronary intervention (P = .02), and surgical revascularization (P = .02). Multivariate predictors for in-hospital mortality include older age (odds ratio [OR], 1.019; P = .007), cardiac arrest (OR, 2.76; P = .006), chronic liver disease (OR, 8.87; P = .04), elevated total bilirubin (OR, 1.093; P < .0001), and the presence of a left ventricular vent (OR, 2.018; P = .03). Pre-ECMO sinus rhythm was protective (OR, 0.374; P = .006). CONCLUSIONS: In a large study of recent VA-ECMO patients, in-hospital mortality remains significant, but acceptable given the severe pathology manifested in this population. Identification of pre-ECMO predictors of mortality helps stratify high-risk patients when deciding on ECMO placement, prolonged support, and prognosis.

Early Results of a Novel Single-Stage Hybrid Aortic Arch Replacement Technique to Reduce Bypass and Circulatory Arrest Duration.

OBJECTIVE: Hybrid repair procedures of the aortic arch have been utilized to reduce surgical risks and apply this therapy to patients who would not traditionally be candidates for open surgical repair.  We present a variation on the frozen elephant trunk technique to further reduce cardiopulmonary bypass and circulatory arrest duration. METHODS: After initiation of cardiopulmonary bypass and during systemic cooling, a wire is advanced from the femoral artery into the aortic arch.  In the case of aortic dissection, intravascular ultrasound is used to confirm true lumen placement.  Under circulatory arrest, the proximal aortic arch is resected and the wire externalized.  Antegrade deployment of a stent graft is performed into the aortic arch and proximal descending aorta.  The ascending aortic graft is sewn to the cut end of the aorta, incorporating the stent graft.  The graft is cannulated and cardiopulmonary bypass reinitiated.  The remainder of the arch replacement is performed during re-warming. RESULTS: Twenty two patients underwent this novel hybrid arch replacement procedure for aortic pseudoaneurysm, aortic dissection, or aneurysm.  In comparison to the frozen elephant trunk procedure, where a dacron graft is inserted into the descending aorta, and later fixed with an endograft, this technique allows for immediate distal fixation.  In the case of aortic dissection, there is immediate expansion of the true lumen with distal seal, potentially obviating the need for additional procedures.  Mean duration of follow up is 12 months (range 1 - 14 months).  The mean duration of cardiopulmonary bypass was 109.32 ±3.14 minutes.  The mean duration of circulatory arrest was 18.00 ±1.33 minutes at a mean temperature of 23.64 ±0.58 degrees Celsius.  There were no mortalities, no permanent disabling strokes, and no renal failure (requiring dialysis). CONCLUSIONS: This novel hybrid technique for aortic arch replacement is safe, significantly reduces cardiopulmonary bypass and circulatory arrest times, and is performed readily without need for fluoroscopy.  In patients with thoracoabdominal aneurysms, the stent graft can be used as an elephant trunk for further thoracoabdominal aneurysm repair or branched thoracic endovascular aortic repair procedures.

Cardiac Emergencies in Patients with Left Ventricular Assist Devices.

Continuous-flow left ventricular assist devices are frequently used for management of patients with advanced heart failure with reduced ejection fraction. Although technologic advancements have contributed to improved outcomes, several complications arise over time. These complications result from several factors, including medication effects, physiologic responses to chronic exposure to circulatory support that is minimally/entirely nonpulsatile, and dysfunction of the device itself. Clinical presentation can range from chronic and indolent to acute, life-threatening emergencies. Several areas of uncertainty exist regarding best practices for managing complications; however, growing awareness has led to development of new guidelines to reduce risk and improve outcomes.

Predictors of Acute Kidney Injury Following Aortic Arch Surgery.

BACKGROUND: Acute kidney injury (AKI) following open aortic arch surgery is a frequent complication associated with increased morbidity and mortality. The primary purpose of this study was to evaluate risk factors for postoperative AKI in patients who underwent open aortic arch surgery utilizing hypothermic circulatory arrest (HCA). MATERIALS AND METHODS: Included were 295 patients undergoing surgery between January 2011 and March 2018. AKI was defined according to Kidney Disease: Improving Global Outcomes guidelines. Preoperative and intraoperative variables were stratified by no AKI versus any AKI, and bivariate analysis was performed. Multivariable logistic regression analysis used statistically and clinically significant characteristics from the bivariate analysis. RESULTS: Of the 295 patients, 93 (32%) developed AKI. In the bivariate analysis, significant predictors of AKI included the following: history of hypertension (P < 0.001), diabetes (P = 0.03), operative urgency (P = 0.009), cardiopulmonary bypass (CPB) time (P < 0.0001), HCA time (0.02), total intraoperative transfusions (P = 0.002), and concomitant procedures (coronary artery bypass grafting, or mitral/tricuspid interventions, P = 0.0009). In the multivariable analysis, significant predictors of AKI were history of hypertension (P = 0.03) and CPB time (P = 0.02). Age, operative urgency, circulatory arrest time, and any intraoperative transfusion were not significant in the multivariable analysis. CONCLUSION: In conclusion, given that CPB time is the only modifiable risk factor identified in the analysis, approaches to reducing bypass time should continue to be the focus of decreasing risk for postoperative AKI in HCA cases.

Transapical Endovascular Repair of an Ascending Aortic Pseudoaneurysm.

Proximal aortic pathology provides a technical challenge for endovascular repair. We present a case of successful transapical endovascular aortic repair in a patient with a proximal suture line pseudoaneurysm who was not a candidate for open surgical repair. doi: 10.1111/jocs.12766 (J Card Surg 2016;31:456-460).

Transcatheter aortic valve repair for management of aortic insufficiency in patients supported with left ventricular assist devices.

The development of new aortic insufficiency after a period of support with a left ventricular assist device can result in progressive heart failure symptoms. Transcatheter aortic valve repair can be an effective treatment in selected patients, but the lack of aortic valve calcification can result in unstable prostheses or paravalvular leak. We describe a technique of deploying a self-expanding CoreValve (Medtronic, Minneapolis, MN, USA) into the aortic annulus, followed by a balloon-expandable SAPIEN-3 (Edwards, Irvine, CA, USA).

Late Surgical Bleeding Following Total Artificial Heart Implantation.

INTRODUCTION: Mechanical circulatory support for heart failure, including the Total Artificial Heart (TAH, Syncardia, Tucson, AZ, USA) has increased in recent years. This report describes bleeding complications associated with the device. METHODS: A single institution prospectively maintained quality improvement database was reviewed encompassing the first year of clinical experience with the TAH. Patients who underwent TAH implantation were identified, and a review of complications and outcomes was undertaken. RESULTS: Ten patients underwent TAH implant. Four patients experienced delayed postoperative bleeding. In three patients the manifestation of bleeding was tamponade and evidenced by TAH decreased cardiac output. In two patients, at postoperative days 31 and 137, there was a partial disruption of the aortic anastomosis along the outer curvature with pseudoaneurysm formation. Both were repaired by primary suture closure, without use of cardiopulmonary bypass. There was no mortality attributable to bleeding. CONCLUSIONS: TAH patients are at risk for delayed postoperative bleeding, often manifest as an acute decrease in cardiac output. Due to pulsatility and high dP/dT, bleeding from the aortic anastomosis should be considered in the differential of a patient with low flow and/or tamponade.

Understanding Embolus Transport And Source To Destination Mapping Of Thromboemboli In Hemodynamics Driven By Left Ventricular Assist Device.

Left Ventricular Assist Devices (LVADs) are a key treatment option for patients with advanced heart failure, but they carry a significant risk of thromboembolic complications. While improved LVAD design, and systemic anticoagulation regimen, have helped mitigate thromboembolic risks, ischemic stroke due to adverse thromboembolic events remains a major concern with current LVAD therapies. Improved understanding of embolic events, and embolus movement to the brain, is critical to develop techniques to minimize risks of occlusive embolic events such as a stroke after LVAD implantation. Here, we address this need, and devise a quantitative in silico framework to characterize thromboembolus transport and distrbution in hemodynamics driven by an operating LVAD. We conduct systematic numerical experiments to quantify the source-to-destination transport patterns of thromboemboli as a function of: LVAD outflow graft anastomosis, LVAD operating pulse modulation, thromboembolus sizes, and origin locations of emboli. Additionally, we demonstrate how the resulting embolus distribution patterns compare and correlate with descriptors based solely on hemodynamic patterns such as helicity, vorticity, and wall shear stress. Using the concepts of size-dependent embolus-hemodynamics interactions, and two jet flow model for hemodynamics under LVAD operation as established in our prior works, we gain valuable insights on departure of thromboembolus distribution from flow distribution, and establish that our in silico model can generate deep insights into embolus dynamics which is not otherwise available from standard of care imaging and clinical data.

Access to durable LVAD therapy for patients with limited social support: Surveying program-specific approaches.

Racial and ethnic disparities in provision of left ventricular assist device (LVAD) therapy have been identified. These disparities may be at least partially related to socioeconomic factors, including social support networks and financial constraints. This study aimed to identify specific barriers, and variations in institutional approaches, to the provision of equitable care to underserved populations. A survey was administered to 237 LVAD program personnel, including physicians, LVAD coordinators, and social workers, at more than 100 LVAD centers across 7 countries. Three fourths of respondents reported that their program required a support person to live with the LVAD patient for some period of time following implantation. In addition, 31% of respondents reported that patients with the inability to pay for medications are turned down at their program. The most significant barriers to successful LVAD implantation were lack of social support, lack of insurance, and lack of timely referral. The most consistently identified supports needed from the hospital system for success in underserved populations were the provision of a solution for patient transportation to and from hospital visits and the provision of financial support. This survey highlights the challenges facing LVAD programs that care for underserved patient populations and sets the stage for specific interventions aimed at reducing disparities in access to care.

Highly sensitized patients listed for heart after liver transplantation with or without domino.

For patients with end-stage heart disease and borderline hemodynamics, high human leukocyte antigen allosensitization presents a barrier to heart transplantation in a timely manner. Conventional desensitization protocols are inadequate in this context due to time constraints and for the most highly reactive immunologically. We previously reported performing heart after liver transplant with domino liver transplant on a single patient without liver disease. We describe this patient's course to date as well as 4 subsequent patients listed for this novel therapy. This experience demonstrates that the liver effectively confers immunoprotection to the heart for patients with high-titer, preformed antibodies. This strategy may provide some measure of equity for demographic groups previously disadvantaged for heart transplantation due to allosensitization.

Quantitative Assessment of Aortic Hemodynamics for Varying Left Ventricular Assist Device Outflow Graft Angles and Flow Pulsation.

Left ventricular assist devices (LVADs) comprise a primary treatment choice for advanced heart failure patients. Treatment with LVAD is commonly associated with complications like stroke and gastro-intestinal (GI) bleeding, which adversely impacts treatment outcomes, and causes fatalities. The etiology and mechanisms of these complications can be linked to the fact that LVAD outflow jet leads to an altered state of hemodynamics in the aorta as compared to baseline flow driven by aortic jet during ventricular systole. Here, we present a framework for quantitative assessment of aortic hemodynamics in LVAD flows realistic human vasculature, with a focus on quantifying the differences between flow driven by LVAD jet and the physiological aortic jet when no LVAD is present. We model hemodynamics in the aortic arch proximal to the LVAD outflow graft, as well as in the abdominal aorta away from the LVAD region. We characterize hemodynamics using quantitative descriptors of flow velocity, stasis, helicity, vorticity and mixing, and wall shear stress. These are used on a set of 27 LVAD scenarios obtained by parametrically varying LVAD outflow graft anastomosis angles, and LVAD flow pulse modulation. Computed descriptors for each of these scenarios are compared against the baseline flow, and a detailed quantitative characterization of the altered state of hemodynamics due to LVAD operation (when compared to baseline aortic flow) is compiled. These are interpreted using a conceptual model for LVAD flow that distinguishes between flow originating from the LVAD outflow jet (and its impingement on the aorta wall), and flow originating from aortic jet during aortic valve opening in normal physiological state.

The Relation Between Viscous Energy Dissipation and Pulsation for Aortic Hemodynamics Driven by a Left Ventricular Assist Device.

Left ventricular assist device (LVAD) provides mechanical circulatory support for patients with advanced heart failure. Treatment using LVAD is commonly associated with complications such as stroke and gastro-intestinal bleeding. These complications are intimately related to the state of hemodynamics in the aorta, driven by a jet flow from the LVAD outflow graft that impinges into the aorta wall. Here we conduct a systematic analyses of hemodynamics driven by an LVAD with a specific focus on viscous energy transport and dissipation. We conduct a complementary set of analysis using idealized cylindrical tubes with diameter equivalent to common carotid artery and aorta, and a patient-specific model of 27 different LVAD configurations. Results from our analysis demonstrate how energy dissipation is governed by key parameters such as frequency and pulsation, wall elasticity, and LVAD outflow graft surgical anastomosis. We find that frequency, pulsation, and surgical angles have a dominant effect, while wall elasticity has a weaker effect, in determining the state of energy dissipation. For the patient-specific scenario, we also find that energy dissipation is higher in the aortic arch and lower in the abdominal aorta, when compared to the baseline flow without an LVAD. This further illustrates the key hemodynamic role played by the LVAD outflow jet impingement, and subsequent aortic hemodynamics during LVAD operation.

Hemodynamics Indicates Differences Between Patients With And Without A Stroke Outcome After Left Ventricular Assist Device Implantation.

Stroke remains a leading cause of complications and mortality in heart failure patients treated with LVAD circulatory support. Hemodynamics plays a central role in affecting risk and etiology of stroke during LVAD support. Yet, detailed quantitative assessment of hemodynamic variables and their relation to stroke outcomes in patients with an implanted LVAD remains a challenge. We present an in silico hemodynamics analysis in a set of 12 patients on LVAD support; 6 with reported stroke outcomes and 6 without. We conducted patient-specific hemodynamics simulations for models with the LVAD outflow graft reconstructed from cardiac-gated CT images. A pre-implantation baseline flow model was virtually generated for each case by removing the LVAD outflow graft and driving flow from the aortic root. Hemodynamics was characterized using quantitative descriptors for helical flow, vortex generation, and wall shear stress. Our analysis showed higher average values for descriptors of positive helical flow, vortex generation, and wall shear stress, across the 6 cases with stroke outcomes on LVAD support, when compared with cases without stroke. When the descriptors for LVAD-driven flow were compared against estimated baseline flow pre-implantation, extent of positive helicity was higher, and vorticity and wall shear were lower in cases with stroke compared to those without. The study suggests that quantitative analysis of hemodynamics after LVAD implantation; and hemodynamic alterations from a pre-implant flow scenario, can potentially reveal hidden information linked to stroke outcomes during LVAD support. This has broad implications on understanding stroke etiology, LVAD treatment planning, surgical optimization, and efficacy assessment.

Atrial septal defect repair by inversion of a juxtaposed left atrial appendage.

A 7-year-old child was noted to have dextrojuxtaposition of the left atrial appendage at the time of surgical atrial septal defect repair. Given the favourable anatomic location and size of the atrial appendage, it was inverted and used to close the atrial defect. This is the first report of atrial septal defect repair using a juxtaposed atrial appendage. The cardiac anatomy and theoretical benefits of this repair are discussed.