Appraisal of Donation After Circulatory Death: How Far Could We Expand the Heart Donor Pool?

BACKGROUND: the incidence of organ donation after circulatory death (DCD) is increasing; however, heart use has lagged behind other solid organs. Ex vivo perfusion devices are under United States Food and Drug Administration review for use in DCD heart recovery. This study sought to measure the potential increase in the donor pool if DCD heart donation becomes widely adopted. METHODS: DCD donor data were obtained from Organ Procurement and Transplantation Network database. Selection criteria included donor age 18 to 49 years, donors meeting Maastricht III criteria, warm ischemia time ≤30 minutes, and donation between 2015 and 2020. Exclusion criteria were coronary disease, prior myocardial infarction, ejection fraction <0.50, significant valve disease, bacteremia, pulmonary capillary wedge pressure >15 mm Hg, and history of HIV/hepatitis C virus infections. RESULTS: There were 12 813 DCD donors during this period, of which 3528 met study criteria, and 70 hearts (2%) were transplanted. The use of DCD hearts would represent an additional 48 heart transplants per month, which corresponds to a 21% (3458 of 16 521) increase across the country. Median warm ischemia was 23 minutes, with no difference between hearts that were or were not transplanted (23 vs 22.5 minutes, P = .97). The frequency with which other organs were successfully transplanted was kidney, 92%; liver, 44%; lung, 7%; intestine, 0%; and pancreas, 2%. CONCLUSIONS: Wide adoption of DCD heart transplantation could yield a substantial increase in the donor pool size, with approximately 580 additional organs being available each year across the United States. This would represent the largest increase in the donor pool in the modern era of heart transplantation.

Creatinine elevations from baseline at the time of cardiac surgery are associated with postoperative complications.

OBJECTIVES: Baseline kidney function is a key predictor of postoperative morbidity and mortality. Whether an increased creatinine at the time of surgery, compared with the lowest creatinine in the 3 months before surgery, is associated with poor outcomes has not been evaluated. We examined whether creatinine elevations from "baseline" were associated with adverse postoperative outcomes. METHODS: A total of 1486 patients who underwent cardiac surgery at the University of Colorado Hospital between January 2011 and May 2016 met inclusion criteria. "Change in creatinine from baseline" was defined as the difference between the immediate presurgical creatinine value and the lowest creatinine value within 3 months preceding surgery. Outcomes evaluated were in-hospital mortality, postoperative infection, postoperative stroke, development of stage 3 acute kidney injury, intensive care unit length of stay, and hospital length of stay. Outcomes were adjusted using a balancing score to account for differences in patient characteristics. RESULTS: There were significant increases in the odds of postoperative infection (odds ratio, 1.17; confidence interval, 1.02-1.34; per 0.1 mg/dL increase in creatinine), stage 3 acute kidney injury (odds ratio, 1.44; confidence interval; 1.18-1.75), intensive care unit length of stay (odds ratio, 1.13; confidence interval, 1.01-1.26), and hospital length of stay (odds ratio, 1.09; confidence interval, 1.05-1.13). There was a significant increase in mortality in the unadjusted analysis, although not after adjustment using a balancing score. There was no association with postoperative stroke. CONCLUSIONS: Elevations in creatinine at the time of surgery above the "baseline" level are associated with increased postoperative morbidity. Baseline creatinine should be established before surgery, and small changes in creatinine should trigger heightened vigilance in the postoperative period.

Open surgical ablation of ventricular tachycardia: Utility and feasibility of contemporary mapping and ablation tools.

BACKGROUND: Ventricular tachycardia (VT) catheter ablation success may be limited when transcutaneous epicardial access is contraindicated. Surgical ablation (SurgAbl) is an option, but ablation guidance is limited without simultaneously acquired electrophysiological data. OBJECTIVE: We describe our SurgAbl experience utilizing contemporary electroanatomic mapping (EAM) among patients with refractory VT storm. METHODS: Consecutive patients with recurrent VT despite antiarrhythmic drugs (AADs) and prior ablation, for whom percutaneous epicardial access was contraindicated, underwent open SurgAbl using intraoperative EAM guidance. RESULTS: Eight patients were included, among whom mean age was 63 ± 5 years, all were male, mean left ventricular ejection fraction was 39% ± 12%, and 2 (25%) had ischemic cardiomyopathy. Reasons for surgical epicardial access included dense adhesions owing to prior cardiac surgery, hemopericardium, or pericarditis (n = 6); or planned left ventricular assist device (LVAD) implantation at time of SurgAbl (n = 2). Cryoablation guided by real-time EAM was performed in all. Goals of clinical VT noninducibility or core isolation were achieved in 100%. VT burden was significantly reduced, from median 15 to 0 events in the month pre- and post-SurgAbl (P = .01). One patient underwent orthotopic heart transplantation for recurrent VT storm 2 weeks post-SurgAbl. Over mean follow-up of 3.4 ± 1.7 years, VT storm-free survival was achieved in 6 (75%); all continued AADs, although at lower dose. CONCLUSION: Surgical mapping and ablation of refractory VT with use of contemporary EAM is feasible and effective, particularly among patients with contraindication to percutaneous epicardial access or with another indication for cardiac surgery.

Noteworthy Literature of 2020: COVID Effects in Cardiac Surgery.

COVID-19 has affected every aspect of life over the last year. This article reviews some of the effects that the pandemic had on cardiac surgery including volumes, ethical concerns with resource-intense procedures like dissection and transplant, and ECMO for COVID-19-derived refractory respiratory failure.

Stage 1 acute kidney injury is independently associated with infection following cardiac surgery.

OBJECTIVES: Severe acute kidney injury (AKI) is a known risk factor for infection and mortality. However, whether stage 1 AKI is a risk factor for infection has not been evaluated in adults. We hypothesized that stage 1 AKI following cardiac surgery would independently associate with infection and mortality. METHODS: In this retrospective propensity score-matched study, we evaluated 1620 adult patients who underwent nonemergent cardiac surgery at the University of Colorado Hospital from 2011 to 2017. Patients who developed stage 1 AKI by Kidney Disease Improving Global Outcomes creatinine criteria within 72 hours of surgery were matched to patients who did not develop AKI. The primary outcome was an infection, defined as a new surgical-site infection, positive blood or urine culture, or development of pneumonia. Secondary outcomes included in-hospital mortality, stroke, and intensive care unit (ICU) and hospital length of stay (LOS). RESULTS: Stage 1 AKI occurred in 293 patients (18.3%). Infection occurred in 20.9% of patients with stage 1 AKI compared with 8.1% in the no-AKI group (P < .001). In propensity-score matched analysis, stage 1 AKI independently associated with increased infection (odds ratio [OR]; 2.24, 95% confidence interval [CI], 1.37-3.17), ICU LOS (OR, 2.38; 95% CI, 1.71-3.31), and hospital LOS (OR, 1.30; 95% CI, 1.17-1.45). CONCLUSIONS: Stage 1 AKI is independently associated with postoperative infection, ICU LOS, and hospital LOS. Treatment strategies focused on prevention, early recognition, and optimal medical management of AKI may decrease significant postoperative morbidity.

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.

Noteworthy Cardiac Literature 2019: Cerebral Protection, Zone 2 Arch, Intravascular Ultrasonography in Dissection, Heart Allocation, and Mitral Durability.

The year of 2019 continues to have notable literature advancing the practice of cardiac surgery. In this article, topics of discussion will include the evolution of cerebral protection, the advancement of arch surgical techniques, the heart transplant allocation system, and mitral repair approach and durability.

Patient Safety Over Power Hierarchy: A Scoping Review of Healthcare Professionals' Speaking-up Skills Training.

Communication failures in healthcare constitute a major root cause of adverse events and medical errors. Considerable evidence links failures to raise concerns about patient harm in a timely manner with errors in medication administration, hygiene and isolation, treatment decisions, or invasive procedures. Expressing one's concern while navigating the power hierarchy requires formal training that targets both the speaker's emotional and verbal skills and the receiver's listening skills. We conducted a scoping review to examine the scope and components of training programs that targeted healthcare professionals' speaking-up skills. Out of 9,627 screened studies, 14 studies published between 2005 and 2018 met the inclusion criteria. The majority of the existing training exclusively relied on one-time training, mostly in simulation settings, involving subjects from the same profession. In addition, most studies implicitly referred to positional power as defined by titles; few addressed other forms of power such as personal resources (e.g., expertise, information). Almost none addressed the emotional and psychological dimensions of speaking up. The existing literature provides limited evidence identifying effective training components that positively affect speaking-up behaviors and attitudes. Future opportunities include examining the role of healthcare professionals' conflict engagement style or leaders' behaviors as factors that promote speaking-up behaviors.

Thrombocytopenia After Cardiopulmonary Bypass Is Associated With Increased Morbidity and Mortality.

BACKGROUND: Thrombocytopenia is a risk factor for morbidity and mortality in critically ill patients, and is common after cardiopulmonary bypass (CPB). In this study, we evaluate whether thrombocytopenia after CPB is an independent risk factor for postoperative morbidity and mortality. METHODS: We retrospectively evaluated 1364 patients requiring CPB at the University of Colorado Hospital between January 2011 and May 2016. Platelet nadir, absolute change in platelets, and percent change in platelets were modeled as continuous variables. Patients with postoperative thrombocytopenia (defined a nadir <75 × 103/µL within 72 hours) were also compared with patients without thrombocytopenia in a propensity-matched model. The primary outcome was in-hospital mortality, and secondary outcomes included postoperative infection, postoperative acute kidney injury (AKI), postoperative stroke, and prolonged intensive care unit (ICU) and hospital lengths of stay (LOS). RESULTS: Postoperative thrombocytopenia occurred in 356 (26.0%) patients. In multivariable analysis, platelet nadir was significantly inversely associated with mortality (odds ratio [OR], 0.955; 95% confidence interval [CI], 0.934-0.975; P < .001), postoperative infection (OR, 0.992; 95% CI, 0.986-0.999; P = .03), AKI (all stage) (OR, 0.993; 95% CI, 0.988-0.998; P = .01), AKI (stage 3) (OR, 0.966; 95% CI, 0.951-0.982; P < .001), postoperative stroke (OR, 0.974; 95% CI, 0.956-0.992; P = .006), prolonged ICU stay (OR, 0.986; 95% CI, 0.981-0.991; P < .001), and hospital LOS (OR, 0.998; 95% CI, 0.997-0.999; P = .001). Percent change in platelets from baseline was also significantly associated with all primary and secondary outcomes. CONCLUSIONS: Postoperative thrombocytopenia is independently associated with postoperative mortality, AKI, infection, stroke, and prolonged ICU and hospital LOS. Serial platelet monitoring may help identify patients at higher risk of postoperative complications. Further studies investigating strategies to reduce postoperative thrombocytopenia, including reducing CPB time, are needed.

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.

Noteworthy Cardiac Surgical Literature 2018: Value-Based Bundled Payments, Opioid Crisis and Cardiac Surgery, Percutaneous Suction Thrombectomy for Intracardiac/Caval Thrombus and Vegetations, and Minimally Invasive Left Ventricular Assist Device Placement.

There has been tremendous evolution in the care of cardiac surgical patients in 2018. In this article, 4 topics of considerable impact on cardiac surgical care in the current landscape are reviewed based on recent publications. The first topic reviews the recent paradigm shift to value-based payments and the potential role of bundled payments on health care and physician reimbursement. The second topic highlights the impact of the opioid crisis on cardiac surgery. The third topic demonstrates the increasing utilization and expanding role of novel percutaneous suction thrombectomy technique in the extraction of caval and right-sided intracardiac thrombi and vegetations with veno-venous bypass. The final topic reviews the current trend of minimally invasive left ventricular assist device placement. Each of these topics addresses the contemporary issues in cardiac surgery with the reasoning for evolution in our current practices in 2018.

Improved Mortality Associated With the Use of Extracorporeal Membrane Oxygenation.

BACKGROUND: Our objective was to evaluate the association of bridge to transplant (BTT) extracorporeal membrane oxygenation (ECMO) on survival after lung transplantation (LTx) and determine the degree to which transplant center volume affects this relationship. METHODS: Using the United Network for Organ Sharing database, we performed a retrospective cohort study evaluating the survival of patients undergoing LTx between 2005 and 2017. On the basis of previous literature, LTx centers were classified into 3 groups using their average annual LTx volume over the preceding 5 years: less than 25, 25 to 49, and more than 50. Survival of BTT ECMO and non-ECMO patients was analyzed using a log-rank test. Propensity scores for BTT ECMO were calculated, and a weighted proportional hazards model was used to compare BTT ECMO and non-ECMO patients by center volume. RESULTS: There were 20,976 patients who met inclusion criteria, with 611 (2.9%) undergoing BTT ECMO. Overall, BTT ECMO was associated with increased posttransplantation hazard of mortality (hazard ratio, 1.37; 95% confidence interval, 1.14 to 1.64). Kaplan-Meier plots by center volume suggest that BTT ECMO-associated mortality may be mitigated at high-volume LTx centers. In the propensity score-weighted proportional hazards model, we determined that when centers perform more than 35 LTxs per year, the increased hazard of BTT ECMO on mortality is no longer observed. CONCLUSIONS: BTT ECMO can be performed as a bridge to LTx without significantly increasing patient mortality in high-volume centers. Patients undergoing BTT ECMO at LTx centers that perform more than 35 LTxs annually have equivalent mortality to those who do not require ECMO before transplantation.

Pulmonary function tests do not predict mortality in patients undergoing continuous-flow left ventricular assist device implantation.

OBJECTIVES: To investigate the effect of pulmonary function testing on outcomes after continuous flow left ventricular assist device implantation. METHODS: A total of 263 and 239 patients, respectively, had tests of forced expiratory volume in 1 second and diffusing capacity of the lungs for carbon monoxide preoperatively for left ventricular assist device implantations between July 2005 and September 2015. Kaplan-Meier analysis and multivariable Cox regressions were performed to evaluate mortality. Patients were analyzed in a single cohort and across 5 groups. Postoperative intensive care unit and hospital lengths of stay were evaluated with negative binomial regressions. RESULTS: There is no association of forced expiratory volume in 1 second and diffusing capacity of the lungs for carbon monoxide with survival and no difference in mortality at 1 and 3 years between the groups (log rank P = .841 and .713, respectively). Greater values in either parameter were associated with decreased hospital lengths of stay. Only diffusing capacity of the lungs for carbon monoxide was associated with increased intensive care unit length of stay in the group analysis (P = .001). Ventilator times, postoperative pneumonia, reintubation, and tracheostomy rates were similar across the groups. CONCLUSIONS: Forced expiratory volume in 1 second and diffusing capacity of the lungs for carbon monoxide are not associated with operative or long-term mortality in patients undergoing continuous flow left ventricular assist device implantation. These findings suggest that these abnormal pulmonary function tests alone should not preclude mechanical circulatory support candidacy.

Flipping the classroom: Case-based learning, accountability, assessment, and feedback leads to a favorable change in culture.

OBJECTIVE: The 88-week Thoracic Surgery Curriculum is challenging to implement because of the large content in a traditional lecture format. This study investigates flipping the classroom by using a case-based format designed to stimulate resident preparation and engagement. METHODS: The didactic conference format was altered. Curricular reading assignments, case review, and conference participation prepared residents for novel formative assessment quizzes. Ten residents participated, and faculty served as controls. Scores were compared with the use of linear regression adjusted for clustering of responses for each person. A survey was administered to determine impressions of this educational technique. RESULTS: A majority of residents completed curricular readings (82%) and reviewed case presentations (79%). Resident performance initially lagged behind faculty but exceeded faculty performance by the conclusion (interaction P = .047). Junior resident overall performance was superior to senior residents over the entire analysis (P = .026); however, both groups improved over time similarly (P = .34) Increased reading from the curriculum (5% increase per level, P = .001) and case presentation review (6% increase per level, P < .0001) were associated with improved quiz performance. Residents presenting cases at their session performed no better than other quiz-takers for the same session (P = .38). The majority of residents viewed this method favorably. CONCLUSIONS: This method stimulated increased resident participation and engagement in this pilot study. Assessment scores increased at both resident levels, and resident performance exceeded faculty performance with time. By using experiential learning principles, flipping the classroom in this manner may improve educational culture by enhancing accountability, assessment, and feedback.

Outflow Graft Obstruction Treated With Transcatheter Management: A Novel Therapy for a New Diagnosis.

The duration of support in patients with HeartMate II implantation as a bridge to transplant or as destination therapy is rising. As clinical experience continues to grow, physiologic changes contributing to pump malfunction are becoming apparent. Once malfunction is noted with increased power spikes, rises in lactate dehydrogenase and low-flow alarms, thrombosis of the pump is at risk. We describe outflow graft compression and offer an expeditious and definitive management strategy. Our novel management stenting strategy for outflow graft compression will continue to evolve as experience is gained.