Transplantation Outcomes with Donor Hearts after Circulatory Death.

BACKGROUND: Data showing the efficacy and safety of the transplantation of hearts obtained from donors after circulatory death as compared with hearts obtained from donors after brain death are limited. METHODS: We conducted a randomized, noninferiority trial in which adult candidates for heart transplantation were assigned in a 3:1 ratio to receive a heart after the circulatory death of the donor or a heart from a donor after brain death if that heart was available first (circulatory-death group) or to receive only a heart that had been preserved with the use of traditional cold storage after the brain death of the donor (brain-death group). The primary end point was the risk-adjusted survival at 6 months in the as-treated circulatory-death group as compared with the brain-death group. The primary safety end point was serious adverse events associated with the heart graft at 30 days after transplantation. RESULTS: A total of 180 patients underwent transplantation; 90 (assigned to the circulatory-death group) received a heart donated after circulatory death and 90 (regardless of group assignment) received a heart donated after brain death. A total of 166 transplant recipients were included in the as-treated primary analysis (80 who received a heart from a circulatory-death donor and 86 who received a heart from a brain-death donor). The risk-adjusted 6-month survival in the as-treated population was 94% (95% confidence interval [CI], 88 to 99) among recipients of a heart from a circulatory-death donor, as compared with 90% (95% CI, 84 to 97) among recipients of a heart from a brain-death donor (least-squares mean difference, -3 percentage points; 90% CI, -10 to 3; P<0.001 for noninferiority [margin, 20 percentage points]). There were no substantial between-group differences in the mean per-patient number of serious adverse events associated with the heart graft at 30 days after transplantation. CONCLUSIONS: In this trial, risk-adjusted survival at 6 months after transplantation with a donor heart that had been reanimated and assessed with the use of extracorporeal nonischemic perfusion after circulatory death was not inferior to that after standard-care transplantation with a donor heart that had been preserved with the use of cold storage after brain death. (Funded by TransMedics; ClinicalTrials.gov number, NCT03831048.).

New Intercostal Transcatheter Aortic Valve Replacement Access: No Touch.

Transcatheter aortic valve replacement (TAVR) is routinely performed via the transfemoral or transapical route. Subclavian, transcarotid, and transaortic access are described as alternative routes for TAVR. The small intercostal approach can be used for a safe TAVR without touching the ribs and sternum.

Transcatheter Mitral Valve Replacement: A Novel Anchor Technology.

BACKGROUND: Mitral valved stents tend to migrate or to develop paravalvular leakage due to high-left ventricular pressure in this cavity. Thus, this study describes a newly developed mitral valved stent anchoring technology. METHODS: Based on an existing mitral valved stent, four anchoring units with curved surgical needles were designed and fabricated using three-dimensional (3D) software and print technology. Mitral nitinol stents assembled with four anchoring units were successively fixed on 10 porcine annuli. Mechanical tests were performed with a tensile force test system and recorded the tension forces of the 10 nitinol stents on the annulus. RESULTS: The average maximum force was 28.3 ± 5.21 N, the lowest was 21.7 N, and the highest was 38.6 N until the stent lost contact with the annulus; for the break force (zero movement of stent from annulus), the average value was 18.5 ± 6.7 N with a maximum value of 26.9 N and a minimum value of 6.07 N. It was additionally observed that the puncture needles of the anchoring units passed into the mitral annulus in all 10 hearts and further penetrated the myocardium in only one additional heart. The anchoring units enhanced the tightness of the mitral valved stent and did not destroy the circumflex coronary artery, coronary sinus, right atrium, aortic root, or the left ventricular outflow tract. CONCLUSION: The new anchoring units for mitral nitinol stents were produced with 3D software and printing technology; with this new type of anchoring technology, the mitral valved stent can be tightly fixed toward the mitral annulus.

A machine learning approach to high-risk cardiac surgery risk scoring.

INTRODUCTION: In patients undergoing high-risk cardiac surgery, the uncertainty of outcome may complicate the decision process to intervene. To augment decision-making, a machine learning approach was used to determine weighted personalized factors contributing to mortality. METHODS: American College of Surgeons National Surgical Quality Improvement Program was queried for cardiac surgery patients with predicted mortality ≥10% between 2012 and 2019. Multiple machine learning models were investigated, with significant predictors ultimately used in gradient boosting machine (GBM) modeling. GBM-trained data were then used for local interpretable model-agnostic explanations (LIME) modeling to provide individual patient-specific mortality prediction. RESULTS: A total of 194 patient deaths among 1291 high-risk cardiac surgeries were included. GBM performance was superior to other model approaches. The top five factors contributing to mortality in LIME modeling were preoperative dialysis, emergent cases, Hispanic ethnicity, steroid use, and ventilator dependence. LIME results individualized patient factors with model probability and explanation of fit. CONCLUSIONS: The application of machine learning techniques provides individualized predicted mortality and identifies contributing factors in high-risk cardiac surgery. Employment of this modeling to the Society of Thoracic Surgeons database may provide individualized risk factors contributing to mortality.

Amiodarone Use Prior to Cardiac Transplant Impacts Early Post-Transplant Survival.

PURPOSE: It remains unclear if use of amiodarone pre-cardiac transplantation impacts early post-transplant survival. METHODS: We selected all patients undergoing heart transplant from 2004 to 2006 with available information using the United Network for Organ Sharing database (n = 4057). Multivariable Cox models compared the risk of death within 30 days post-transplant in patients who were taking amiodarone at the time of transplant listing (n = 1227) to those who were not (n = 2830). RESULTS: Mean age was 52 (± 12) years, and 23% were women. Patients who died within 30 days (n = 168) were older; had higher panel reactive antibody levels, higher bilirubin levels, and higher prevalence of prior cardiac surgery; were often at status 1B; and had higher use of amiodarone at listing compared to those who survived (5.3% versus 3.6%; p = 0.02). Cause of death was unknown in 49% and was reported as graft failure in 43% of cases. In multivariable Cox models, patients on amiodarone at the time of listing had 1.56-fold higher risk of post-transplant death within 30 days (95% confidence intervals 1.08-2.27) compared to patients who were not on amiodarone at listing (C-statistic 0.70). CONCLUSION: In conclusion, patients who reported taking amiodarone at the time of listing for transplant had a higher risk of death within 30 days post-transplant.

A Dual Atrioventricular Approach to Repair Pseudoaneurysm after Mitral Valve Surgery.

Background Left ventricular pseudoaneurysm (LVPA) is an uncommon but potentially fatal complication following atrioventricular groove rupture. Case Description We present a patient with a massive LVPA involving the lateral commissure and under the mitral P3 segment following coronary artery bypass grafting and mitral valve (MV) repair. MV replacement and arteriovenous pseudoaneurysm were repaired by dual approach via the left atrium with excision of the previously dehisced mitral ring to expose the defect and patch repair the atrioventricular defect through the pseudoaneurysm free wall. Conclusion This is a rare case of a large subacute postoperative LVPA repaired by dual atrial-ventricular approach to treat a contained atrioventricular groove rupture.

Mitochondrial DNA deletion mutations in adult mouse cardiac side population cells.

We investigated the presence and potential role of mitochondrial DNA (mtDNA) deletion mutations in adult cardiac stem cells. Cardiac side population (SP) cells were isolated from 12-week-old mice. Standard polymerase chain reaction (PCR) was used to screen for the presence of mtDNA deletion mutations in (a) freshly isolated SP cells and (b) SP cells cultured to passage 10. When present, the abundance of mtDNA deletion mutation was analyzed in single cell colonies. The effect of different levels of deletion mutations on SP cell growth and differentiation was determined. MtDNA deletion mutations were found in both freshly isolated and cultured cells from 12-week-old mice. While there was no significant difference in the number of single cell colonies with mtDNA deletion mutations from any of the groups mentioned above, the abundance of mtDNA deletion mutations was significantly higher in the cultured cells, as determined by quantitative PCR. Within a single clonal cell population, the detectable mtDNA deletion mutations were the same in all cells and unique when compared to deletions of other colonies. We also found that cells harboring high levels of mtDNA deletion mutations (i.e. where deleted mtDNA comprised more than 60% of total mtDNA) had slower proliferation rates and decreased differentiation capacities. Screening cultured adult stem cells for mtDNA deletion mutations as a routine assessment will benefit the biomedical application of adult stem cells.

Adopting robotic thoracic surgery impacts hospital overall lung resection case volume.

PURPOSE: We sought to evaluate the role of robotic-assisted lung surgery on hospital volume using difference in difference (DID). We propose hospital adoption of robotic thoracic technology increases total volume of specific procedures as compared to non-robotic hospitals. METHODS: The 2010-2015 Florida Agency for Health Care Administration dataset was queried for open, video-assisted thoracoscopic, and robotic-assisted thoracic surgeries. Incident Rate Ratios (IRR) from DID analysis determined the significance of robotic technology. For each technique, length of stay and elements of charges were compared to determine statistical significance. RESULTS: A total of 28,484 lung resection procedures performed at 162 hospitals, 65 of which had robotic capabilities were included. Robotic hospitals experienced an 85% increase in total lung surgical volume (IRR 1.85, p-value <0.001). This increase in volume was consistent for each lung resection procedure separately. CONCLUSION: Hospital adoption of robotic technology significantly increases the overall lung surgical volume for select lung resection procedures.

Introduction of transcatheter aortic valve replacement technology increases overall aortic valve surgical volume: Evaluating the Florida experience.

OBJECTIVE: Transcatheter aortic valve replacement technology is increasingly used for aortic valve stenosis. We sought to evaluate the adoption of transcatheter aortic valve replacement technology with respect to overall surgical aortic valve replacement volume in Florida. METHODS: The 2010-2019 Florida Agency for Health Care Administration data set was queried. Difference-in-difference analysis was used to evaluate the impact of transcatheter aortic valve replacement on the total aortic valve surgical volume of transcatheter aortic valve replacement versus nonperforming hospitals. Length of stay and elements of charges were compared for the raw and 1:1 propensity matched data. RESULTS: A total of 46,032 surgical aortic valve procedures were performed at 88 hospitals. Transcatheter aortic valve replacement performing hospitals experienced a 21% increase in total aortic valve surgical volume. Length of stay was significantly less for patients undergoing transcatheter aortic valve replacement. Propensity matched transcatheter aortic valve replacement patients had less gross total charges. CONCLUSION: Introduction of transcatheter aortic valve replacement technology significantly increased overall surgical aortic valve volume and may be associated with less gross total hospital charges.

Outcomes of Transcatheter and Surgical Aortic Valve Replacement in Distressed Socioeconomic Communities.

Objective Patients of low socioeconomic status have an increased risk of complications following cardiac surgery. We aimed to identify disparities in patients undergoing aortic valve replacement using the Distressed Communities Index (DCI), a comparative measure of community well-being. The DCI incorporates seven distinct socioeconomic indicators into a single composite score to depict the economic well-being of a community. Methods The Healthcare Cost and Utilization Project State Inpatient Database (HCUP-SID) for Florida and Washington was queried to identify patients undergoing surgical and transcatheter aortic valve replacement (surgical aortic valve replacement [SAVR], transcatheter aortic valve replacement [TAVR]) between 2012-2015. Patients undergoing TAVR and SAVR were propensity-matched and stratified based on the quintile of DCI score. A distressed community was defined as those in quintiles 4 and 5 (at-risk and distressed, respectively); a non-distressed community was defined as those in quintiles 1 and 2 (prosperous and comfortable, respectively). Outcomes following aortic valve replacement were compared across groups in distressed communities. Propensity score matching was used to balance baseline covariates between groups. Results A total of 27,591 patients underwent aortic valve replacement. After propensity matching, 5,331 patients were identified in each TAVR and SAVR group. Distressed TAVR patients had lower rates of postoperative pneumonia (7.6% vs. 3.8%, p<0.001), sepsis (3.6% vs. 1.9%, p<0.05), and cardiac complications (15.4% vs. 7.5%, p<0.001) when compared to highly distressed SAVR patients. When comparing distressed SAVR and TAVR and low distressed SAVR and TAVR groups, no significant difference was found in postoperative outcomes, except distressed TAVR experienced more cases of UTI. Conclusions Highly distressed TAVR patients had lower incidences of postoperative sepsis, pneumonia, and cardiac complications when compared to the highly distressed SAVR cohort. Patients undergoing TAVR in highly distressed communities had an increased incidence of postoperative urinary tract infection. DCI may be a useful adjunct to current risk scoring systems.

Orthotopic Heart Auto-Transplantation in a Swine Model.

BACKGROUND AND AIM: The porcine heart bears the best resemblance to the human heart and remains the preferred preclinical model for anatomical, physiological, and medical device studies. In an effort to study phenomena related strictly to ischemia reperfusion and donor preservation protocols, it is essential to avoid the immune responses related to allotransplantation. Orthotopic auto-transplantation is a unique strategy to the field of cardiac transplantation for ex vivo experimentation. Nevertheless, auto-transplantation carries its own technical challenges related to insufficient length of the great vessels that are to be transected and re-anastomosed. METHODS: A novel method for orthotopic cardiac auto-transplantation in the porcine model was developed and was described herein. Porcine models were used for ex vivo experimentation of a novel device to study ischemia reperfusion injury. RESULTS: A total of five porcine models were used for ex vivo experimentation of a novel device to mitigate ischemia reperfusion injury and determine effects of donor preservation. Modifications to routine cardiac transplantation protocols to allow for successful auto-transplantation are described. CONCLUSION: Orthotopic cardiac auto-transplantation in the porcine model is a plausible and technically feasible method for reliable study of ischemia reperfusion injury and donor preservation protocols. Here, we describe methods for both direct orthotopic porcine cardiac auto-transplantations as well as a simplified protocol that can be substituted for full surgical auto-transplantation for the studies of preservation of donor hearts.

Mitral valved stent implantation: an overview.

To date, transcatheter valve implantation is limited to the replacement of pulmonary and aortic valves. The aim of this study was to analyze a valved stent for minimally invasive implantation in the mitral position. A self-expanding mitral valved stent was designed for transapical implantation. Thirty pigs underwent off-pump mitral valved stent implantation with follow-up times of 60 minutes (n = 17) and seven days (n = 13). Transesophageal echocardiography and computed tomography were used to evaluate stent function and positioning. After valved stent deployment, accurate adjustment of the intra-annular position reduced paravalvular leakage in all animals. Accurate positioning was established in all but five animals. The average mean transvalvular gradient across the mitral valve and the left ventricular outflow tract recorded immediately after deployment, six hours and one week were 1.85 ± 0.95 mmHg, 3.45 ± 1.65 mmHg, 4.15 ± 2.3 mmHg and 1.35 ± 1.35 mmHg, 1.45 ± 0.7 mmHg, 1.9 ± 0.65 mmHg, respectively. No valved stent migration, embolization, systolic anterior movement or left ventricular outflow tract obstruction was observed. The mitral valved stent can be deployed in a reproducible manner to achieve reliable stent stability, minimal gradients across the left ventricular outflow tract and adequate stent function in acute and short term experimental settings.

Less invasive surgical implant strategy and right heart failure after LVAD implantation.

BACKGROUND: Conventional median sternotomy (CMS) is still the standard technique utilized to implant left ventricular assist devices (LVADs). Recent studies suggest that less invasive surgery (LIS) may be beneficial; however, robust data on differences in right heart failure (RHF) are lacking. This study aimed to determine the impact of LIS compared with that of CMS on RHF outcomes after LVAD implantation. METHODS: An international multicenter retrospective cohort study was conducted across 5 centers. Patients were grouped according to their implantation technique (LIS vs CMS). Only centrifugal devices were included. RHF was defined as severe or severe acute RHF according to the 2013 Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) definition. Logistic multivariate regression and propensity score‒matched analyses were performed to account for confounding. RESULTS: Overall, 427 implantations occurred during the study period, with 305 patients implanted using CMS and 122 using LIS. Pre-operative extracorporeal membrane oxygenation (ECMO) and intra-aortic balloon pump (IABP) use was more common in the CMS group; off-pump implantation was more common in the LIS group. Other pre-implant variables, including age, creatinine, hemodynamics, and tricuspid regurgitation, did not differ between the 2 groups. Post-operative RHF was less common in the patients who underwent LIS than in those who underwent CMS as was post-operative right ventricular assist device (RVAD) use. LIS remained associated with less RHF in the multivariate analysis. After propensity score matching conditional for age, sex, INTERMACS profile, ECMO, and IABP use in a ratio of 2:1 (CMS to LIS), RHF (29.9% vs 18.6%, p = 0.001) and the need for post-operative RVAD (18.6% vs 8.2%; p = 0.009) remained more common in the CMS group than in the LIS group. There were no significant differences in survival up to 1 year between the groups. CONCLUSIONS: LIS may be associated with less RHF after LVAD implantation compared with CMS. Despite the possible reduction in RHF, there was no difference in 1-year survival. LIS is an alternative to traditional CMS.

Pulmonary Arterial Elastance and INTERMACS-Defined Right Heart Failure Following Left Ventricular Assist Device.

BACKGROUND: Acute right heart failure (RHF) after left ventricular assist device implantation remains a major source of morbidity and mortality, yet the definition of RHF and the preimplant variables that predict RHF remain controversial. This study evaluated the ability of (1) INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support) RHF classification to predict post-left ventricular assist device survival and (2) preoperative characteristics and hemodynamic parameters to predict severe and severe acute RHF. METHODS AND RESULTS: An international, multicenter study at 4 large academic centers was conducted between 2008 and 2016. All subjects with hemodynamics measured by right heart catheterization within 30 days before left ventricular assist device implantation were included. RHF was defined using the INTERMACS definition for RHF. In total, 375 subjects were included (mean age, 57.4±13.2 years, 54% bridge-to-transplant). Mild RHF was most common (34%), followed by moderate RHF (16%), severe RHF (13%), and severe acute RHF (9%). Estimated on-device survival rates at 2 years were 72%, 71%, and 55% in the patients with none, mild-to-moderate, and severe-to-severe acute RHF, respectively (P=0.004). In addition, the independent hazard ratio for mortality was only increased in the patients with severe-to-severe acute RHF (hazard ratio, 3.95; 95% CI, 2.16-7.23; P<0.001). INTERMACS-defined RHF was superior to postimplant inotrope duration alone in the prediction of all-cause mortality. In multivariable analysis, older age, lower INTERMACS classes, and higher pulmonary arterial elastance (ratio of systolic pulmonary artery pressure to stroke volume) before left ventricular assist device, were identified as significant predictors of severe-to-severe acute RHF. Stratifying patients by ratio of systolic pulmonary artery pressure to stroke volume and right atrial pressure significantly improved the discrimination between patients at risk for severe-to-severe acute RHF. CONCLUSIONS: The INTERMACS RHF classification correctly identifies patients at risk for mortality, though this risk is only increased in patients with severe-to-severe acute RHF. Several predictors for RHF were identified, of which ratio of systolic pulmonary artery pressure to stroke volume was the strongest hemodynamic predictor. Coupling ratio of systolic pulmonary artery pressure to stroke volume with right atrial pressure may be most helpful in identifying patients at risk for severe-to-severe acute RHF.

Inter- and intra-observer repeatability of aortic annulus measurements on screening CT for transcatheter aortic valve replacement (TAVR): Implications for appropriate device sizing.

OBJECTIVES: To investigate intra- and inter-observer repeatability of aortic annulus CT measurements for transcatheter aortic valve replacement (TAVR) by readers with different levels of experience and evaluate the impact of different multi-reader paradigms to improve prosthesis sizing. METHODS: 82 TAVR screening CTAs were evaluated twice by three raters with six (R1 = radiologist), three (R2 = 3D-laboratory technician) or zero (R3 = medical student) years of experience. Results were translated into hypothetical TAVR size recommendations. Intra- and inter-observer repeatability between single readers and three different multi-reader paradigms ([A]: two readers, [B]: three readers, or [C]: two readers + an optional third reader) were evaluated. RESULTS: Intra-observer variability did not differ significantly (range: 50.1-67.8mm2). However, we found significant differences in mean inter-observer variance (p = 0.001). Multi-reader paradigms led to significantly increased precision (lower variability) for scenarios [B] and [C] (p = 0.03, p < 0.05). Compared to single readers, all multi-reader strategies clearly lowered the rate of discrepant device size categorization between repeated measurements (22-26% to 5-10%). CONCLUSIONS: Aortic annulus CT measurements for TAVR are highly reproducible. Multi-reader strategies provide higher precision than evaluations from single readers with different levels of experience and could effectively be implemented with two readers and an optional third reader (Paradigm C) in a clinical setting.

Cardiac Surgery Outcomes in Abdominal Solid Organ Transplant Recipients.

BACKGROUND: Cardiovascular disease is a cause of morbidity and mortality in organ transplant recipients. Cardiac surgery after organ transplantation is not uncommon in this population. We evaluated 30-day outcomes and long-term survival of abdominal transplant recipients undergoing cardiac surgery at our institution. METHODS: In all, 138 patients with previous kidney, kidney-pancreas, and liver transplants underwent cardiac surgery from 2000 to 2016. Propensity score (ratio 1:3) matched 115 abdominal transplant with 345 patients undergoing cardiac surgery without a history of abdominal transplant. They were matched for type and year of cardiac surgery, age, sex, body mass index, history of diabetes mellitus, and creatinine level before cardiac surgery. RESULTS: Median time from abdominal transplant to cardiac surgery was 7 years (interquartile range, 3 to 12 years). Perioperative variables, including surgery and cardiopulmonary bypass time, aortic cross-clamp and intubation time, and intensive care unit stay did not differ between the groups. Hospital length of stay and rate of 30-day hospital readmissions did not differ between the groups. Patients with abdominal transplants had more strokes (4% versus 0.6%; p = 0.005) within 30 days after surgery. There were no differences in renal failure, bleeding, site infections, atrial fibrillation, and pneumonia between the groups. Five patients (4%) died within 30 days after surgery in the abdominal transplant group (4 kidneys, 1 liver, 0 kidney-pancreas), and 7 patients (2%) died in the nontransplanted group (p = 0.24). CONCLUSIONS: Previous history of abdominal transplant is associated with an increased 30-day incidence of stroke after cardiac surgery. Abdominal transplant does not affect 30-day mortality after cardiac surgery, whereas long-term survival is significantly reduced. Regular patient follow-up and prevention and early treatment of postoperative complications are key to patient survival.

Outcomes of surgical aortic valve replacement for mixed aortic valve disease.

BACKGROUND: Mixed aortic valve disease (MAVD) is associated with a poorer natural history compared with isolated lesions. However, clinical and echocardiographic outcomes for aortic valve replacement (AVR) in mixed disease are less well understood. METHODS: Retrospective review of AVRs (n=1,011) from 2000-2016. Isolated AVR, AVR + coronary bypass, and AVR + limited ascending aortic replacement were included. Predominant aortic stenosis (AS) group was stratified into group 1 (n=660) with concomitant mild or less aortic insufficiency (AI), and group 2 (n=197) with accompanying moderate or greater AI. Predominant AI group was stratified using the same schema for concomitant AS into groups 3 (n=143) and 4 (n=53). Median follow-up was 3.1 and 4.4 years respectively for AS and AI groups. RESULTS: For the predominant AS group (n=857) preoperatively, group 2 had a larger preoperative left ventricular end diastolic diameter (LVESD) (51.0±8.4 vs. 48.6±7.2, P=0.02) and lower preoperative left ventricular ejection fraction (LVEF) (57.6% vs. 60.2%, P=0.043). No differences in left ventricular (LV) dimensions, LV or right ventricular (RV) function was evident at follow up (P>0.05). After propensity matching for age, operation, and comorbidities, there was no difference in survival (P=0.19). After propensity matching for the predominant AI group (n=196), survival was lower for group 4 compared to 3 (P=0.02). There were no differences in LV dimensions, LV or RV function preoperatively or on follow-up (P>0.05). CONCLUSIONS: Predominant AS associated with higher AI grades had larger LV dimensions and worse LV function preoperatively. These differences resolve after AVR with equivalent survival. However, predominant AI with more severe AS had reduced survival despite AVR.