The heart transplant allocation change attenuates but does not eliminate blood group O waitlist outcome disadvantage.

BACKGROUND: Patients with blood group O have historically been disadvantaged in the United Network for Organ Sharing (UNOS) heart transplant allocation system. We sought to determine whether the new UNOS allocation system implemented in 2018 had an impact on waitlist and post-transplant outcomes among blood groups. METHODS: Using the UNOS database we included all adult patients listed and transplanted with first-time single-organ heart transplant between 10/17/15 and 10/1/21. For post-transplant outcomes, we separately evaluated all adult patients transplanted with the same time-frame. We used exclusion criteria and censoring to limit biases from changing clinical practices around the allocation change (10/18/2018), and from unequal or inadequate follow-up. We compared clinical characteristics and outcomes before and after the allocation change among each blood group. Fine-Gray and Cox regression models were used to estimate the effect of the new allocation system on competing waitlist outcomes- transplantation, death-or-removal from waitlist- and post-transplant survival, respectively. RESULTS: Of the 21,565 patients listed for transplantation 14,000 met criteria for waitlist analysis (7,035 in the old system vs. 6,965 in the new), and 7,657 met criteria for post-transplant analysis (3,519 in the old system vs. 4,138 in the new). Among each blood group, new allocation change was associated with higher transplantation rates lower waitlist days and lower waitlist mortality (except Group AB). However, despite improvements, Group O was still associated with worse waitlist outcomes for each metric compared to non-O Groups. The new allocation system did not have a significant impact on post-transplant survival among any blood groups. CONCLUSION: Changes in heart transplant allocation have attenuated but not eliminated blood group O disadvantage in access to donor hearts.

The effect of recipient BMI on waitlist and post-transplant outcomes after the 2018 heart transplant allocation policy change.

OBJECTIVE: The effects of recipient body mass index (BMI) on waitlist strategies, waitlist outcomes, and post-transplant outcomes among adult patients listed for heart transplantation under the updated 2018 allocation system have not been well characterized. METHODS: The United Network of Organ Sharing data set between October 2015 and March 2021 was analyzed, and patients were grouped based on recipient BMI and whether listing occurred in the old (pre-October 2018) or new allocation system. RESULTS: Listing strategies differed by BMI group, but trends of increased use of temporary mechanical support and decreased use of durable support remained among all BMI groups, except those with BMI > 35 kg/m2 . Waitlist outcomes improved among all BMI cohorts in the new allocation system, including among patients with BMI 30-34.9 and >35 kg/m2 , although patients with higher BMIs continued to have longer waitlist times. Post-transplant outcomes in the new allocation system are worse for patients with BMI > 30 kg/m2  (hazard ratio: 1.47; confidence interval: 1.19-1.82; p < .001). CONCLUSIONS: The 2018 change to the heart transplant allocation system was associated with similar changes in the use of mechanical support for listing strategy across BMI ranges, except in the most obese, and improved waitlist outcomes across all BMI ranges. Post-transplant outcomes in the new allocation system are worse for patients with BMI > 30 kg/m2  compared to patients with BMI < 30 kg/m2 . These findings have important clinical implications for our understanding of the ongoing influence of BMI on waitlist courses and post-transplant outcomes among patients listed for heart transplantation.

Current status of perioperative temporary mechanical circulatory support during cardiac surgery.

OBJECTIVES: We sought to determine utilization and outcomes of perioperative temporary mechanical circulatory support (tMCS) in the current practice of cardiac surgery. BACKGROUND: tMCS is an evolving adjunct to cardiac surgery not fully characterized in contemporary practice. METHODS: Using the nationwide inpatient sample we retrospectively analyzed hospital discharge data between January 1, 2016 and December 31, 2019. ICD-10-CM procedure codes were used to identify and divide patient hospitalizations into those who had preoperative tMCS (pre-tMCS) versus tMCS instituted the day of surgery or afterwards (sd/post-tMCS). RESULTS: In all, 1,383,520 hospitalizations met inclusion criteria. 86,445 (6.25%) had tMCS. tMCS was utilized in 8.74% of coronary artery bypass grafting (CABG), 2.58% of isolated valve, and 9.71% of valve/CABG; operations. 29,325 (33.9%) had pre-tMCS while 57,120 (66.1%) had sd/post-tMCS. The use of tMCS was associated with greater inpatient mortality (15.66% vs. 1.53%, p < .001), longer length of stay (LOS) (14.4 vs. 8.5 days, p < .001), and higher mean inflation-adjusted costs ($93,040 ± 1038 vs. $51,358 ± 296, p < .001) compared to no use. Inpatient mortality (5.98% vs. 20.63%, p < .001), LOS (13.87 vs. 14.68, p < .001), and cost ($82,621 ± 1152 SEM vs. $98,381 ± 1242) were all significantly lower with pre-tMCS compared to sd/post tMCS. When analyzed separately, mortality was higher with later utilization of tMCS (5.98% pre, 17.1% sd, and 49.05% postsurgical date insertion, p < .001). CONCLUSIONS: Perioperative tMCS is utilized in 6.25% of modern cardiac surgery, with two-thirds of cases instituted on the day of surgery or afterwards. The use of tMCS is associated with significantly higher mortality, longer LOS, and higher costs. Among patients undergoing tMCS, earlier utilization is associated with better outcomes.

Impact of heart transplant allocation change on competing waitlist outcomes among listing strategies.

In 2018, the United Network for Organ Sharing (UNOS) adopted a 6-tier system for heart allocation which shifted patterns in listing strategies. The effects of the change on waitlist survival and transplantation rates have yet to be substantiated by analysis of competing outcomes among various listing strategies. This study included all adult patients listed for first-time heart transplantation in UNOS between 10/17/15 and 6/12/20. Clinical characteristics were compared before and after allocation change among various listing strategies: no support, inotropes, intra-aortic balloon pump, durable left ventricular assist device (LVAD), temporary VAD, and extracorporeal membrane oxygenation. Fine-Gray proportional subhazard models were used to estimate the effect of allocation change on competing waitlist outcomes-transplantation, death, or removal from waitlist-among each strategy. During the study period, there were 17 422 patients listed for heart transplantation. Among each listing strategy, clinical characteristics were similar before and after allocation change. Subhazard models demonstrated reduced risk for waitlist mortality (p < .001) among each strategy except temporary VAD and increased transplantation rates (p < .001) among each strategy except for durable LVAD. These results validate the association of the new allocation system on waitlist outcomes across listing strategies.

Impact of transplant center volume on donor heart offer utilization rates in the United States.

BACKGROUND: We tested the hypothesis that transplant centers (TCs) with higher volumes have higher donor heart (DH) offer utilization rates. METHODS: Using the Annual Data reports of the US Organ Procurement and Transplantation Network and the Scientific Registry of Transplant Recipients (SRTR) we reviewed all adult heart transplant offers between July 1, 2016 and June 29, 2019. Unadjusted donor offer utilization rates and observed to expected (O/E) DH utilization ratios adjusted using the SRTR model were calculated for each TC for all DH offers and for the following sub-categories: DH with left ventricular ejection fraction <60%, DH >40 years, DH >500 miles from TC, "hard-to-place hearts" (defined as those offered to >50 TCs) and DH designated as increased infectious risk. Univariable linear regression was used to identify a relationship between average yearly center volume and DH utilization. RESULTS: During the study 118,841 total offers were made to 107 TCs and 8300 transplants were performed. The unadjusted utilization rate was not associated with TC volume for all donor offers (p = .517). However, among all subcategories other than DH >40 years, the unadjusted DH utilization rate was associated with TC volume (p < .05). In addition, using the adjusted SRTR O/E ratio, there was a significant impact of TC volume on utilization rate for all donor offers (for an increase TC volume of 10 transplants/year coefficient = 0.095, 95% confidence interval: 0.037-0.151, p = .001). This relationship persisted with an identifiable change for each of the subcategories (p ≤ .001). CONCLUSIONS: TC volume is significantly correlated to DH offer utilization rate.

Role of Methadone in Extracorporeal Membrane Oxygenation: Two Case Reports.

Extracorporeal membrane oxygenation (ECMO) affects pharmacokinetics/dynamics of drugs in unpredictable ways. Anecdotally, ECMO patients require high doses of opioids and sedatives, leading to concerns of tolerance. Methadone is a long-acting synthetic opioid with antagonist properties at the n-methyl-d-aspartate (NMDA) receptor. It has been shown to improve spontaneous breathing trials and weaning from mechanical ventilation; however, there is no literature describing its use in ECMO. We describe two patients from the cardiac surgery intensive care unit at Cedars Sinai (Los Angeles, CA) on ECMO for over 30 days maintained on methadone.

Outcomes of coronary artery bypass surgery using modified del Nido cardioplegia in patients with poor ventricular function.

BACKGROUND: del Nido cardioplegia (DN) has been shown to be safe in adult patients undergoing isolated coronary artery bypass grafting with normal left ventricular ejection fraction. We sought to determine whether it was also safe in adult patients with diminished left ventricular function. METHODS: All patients with preoperative left ventricular ejection fraction ≤ 40% undergoing isolated coronary artery bypass grafting between 1/1/2019 and 7/10/2022 were retrospectively analyzed. Off-pump and beating heart cases were excluded. Patients were divided by surgeon preference between conventional cardioplegia (CCP) and DN. Baseline and intraoperative characteristics and short-term postoperative outcomes were compared. RESULTS: Six surgeons performed 829 isolated coronary artery bypass operations during the study. Two-hundred seventy-two met study criteria. Three surgeons used exclusively CCP for the duration of the study, two used exclusively DN and one switched from CCP to DN mid-way through. Group totals were: CCP n = 181 and DN n = 91. There were no significant differences in baseline characteristics including mean left ventricular ejection fraction (CCP 32.5 ± 7.4% vs. DN 33.4 ± 7.29%, p = 0.939). Other than a significant decrease in bypass time for DN (113.20 ± 37.2 vs. 122.43 ± 34.3 min, p = 0.043) there were no intergroup differences in urgency, number of grafts, ischemic time or incidence of blood transfusion. Postoperative outcomes between CCP and DN were similar including incidence of atrial fibrillation (12.2% vs. 8.8%, p = 0.403), intensive care length of stay (3.7 ± 2.3 vs. 4.3 ± 3.7 days, p = 0.886), total length of stay (5.7 ± 3.7 vs. 6.3 ± 4.4 days, p = 0.922) and 30-day mortality (3.85% vs. 1.10%, p = 0.205). CONCLUSION: Compared to conventional cardioplegia, del Nido cardioplegia provides equivalent short-term outcomes in patients with low left ventricular ejection fraction undergoing isolated coronary artery bypass grafting.

Hemorrhagic pericardial effusion resulting in constriction in hereditary hemorrhagic telangiectasia.

BACKGROUND: We report the first ante-mortem diagnosis of hemorrhagic pericardial effusion in hereditary hemorrhagic telangiectasia resulting in constriction; the case also demonstrates the unusual but well-described complication of right-sided heart failure requiring extracorporeal membrane oxygenation (ECMO) support after pericardiectomy. CASE PRESENTATION: A previously healthy 48 year old man with a strong family history of Osler-Weber-Rendu disease presented to our institution with signs and symptoms of advance heart failure. His workup demonstrated a thickened pericardium and constrictive physiology. He was brought to the operating room where old clot and inflamed tissue were appreciated in the pericardial space and he underwent complete pericardiectomy under cardiopulmonary bypass. Separation from bypass, hampered by the development of right ventricular dysfunction and profound vasoplegia, required significant pressor and inotropic support. The right heart dysfunction and vasoplegia worsened in the early postoperative period requiring a week of ECMO after which his right ventricle recovered and he was successfully de-cannulated. CONCLUSION: Given the poor outcome of severe postoperative right ventricular failure after pericardiectomy, with high central venous pressure, a low gradient between central venous and pulmonary artery pressures and high vasopressor requirements, ECMO should be instituted promptly.

Total artificial heart: surgical technique in the patient with normal cardiac anatomy.

Heart failure is a complex, growing problem with significant morbidity and mortality. Though heart transplantation remains the gold standard treatment for end-stage heart failure, there remains a national shortage of donor hearts. Mechanical circulatory support has provided an additional option for clinicians to support patients for the purposes of bridging patients to transplantation or to be used for destination therapy purposes. Despite generally favorable outcomes with univentricular support, in a subset of patients with biventricular heart failure, an isolated left ventricular assist device is not sufficient. Right ventricular failure has a negative impact on patient survival if not identified and treated promptly. The Total Artificial Heart (TAH) is the only Food and Drug Administration (FDA) approved artificial heart used for bridging patients to transplantation. Outcomes in patients who undergo implantation of the TAH at experienced centers have been good and reproducible.

A New Paradigm in Mechanical Circulatory Support: 100-Patient Experience.

BACKGROUND: Acutely decompensated heart failure presents a complicated challenge. Established temporary support measures have significant adverse effects. A minimally invasive temporary left ventricular assist device (LVAD), the Impella 5.0 (Abiomed, Danvers, MA), has been developed to support these patients. METHODS: Patients with acutely decompensated heart failure in whom medical management had failed and who required additional support using an Impella 5.0 device were evaluated from January 2014 to September 2018 at a single center in a retrospective manner using a prospectively maintained database. Patients were treated with the device as a bridge to recovery (BTR; n = 30), bridge to durable device (BTDD; n = 23), or bridge to transplantation (BTT; n = 47). All devices were placed using an axillary artery approach. Demographic features and outcomes were evaluated for each group and compared. RESULTS: A total of 100 patients underwent insertion of an axillary Impella 5.0 LVAD. Patients had an average age of 56.7 ± 13.2 years, were predominantly male (84%), and had a severely depressed left ventricular ejection fraction (average 16%), and most had an Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) profile 1 (57%) or 2 (33%) score. When divided into groups, there was no difference in age or INTERMACS score, but a statistical difference was noted in baseline left ventricular ejection fraction (20%, 14%, 15%) and creatinine level (1.0, 2.0, 1.6), in the BTR, BTDD, or BTT group, respectively (all P < .05). Survival was 64% overall, and it was 50%, 48%, and 81% for BTR, BTDD, and BTT, respectively (P = .007). Survival improved during this experience and was 90% overall in the most recent 30 patients. CONCLUSIONS: Use of this minimally invasive LVAD system is an attractive strategy to support patients with acute decompensated heart failure to recovery, durable LVAD, or heart transplantation.

Combined Heart and Kidney Transplantation: Clinical Experience in 100 Consecutive Patients.

Background Combined heart and kidney transplantation ( HKT x) is performed in patients with severe heart failure and advanced renal insufficiency. We analyzed the long-term survival after HKT x, the influence of age and dialysis status, the rates of cardiac rejection, and the influence of sensitization. Methods and Results From June 1992 to December 2016, we performed 100 HKT x procedures. We compared older (≥60 years, n=53) with younger (<60 years, n=47) recipients, and recipients on preoperative dialysis (n=49) and not on dialysis (n=51). We analyzed actuarial freedom from any cardiac rejection, acute cellular rejection, and antibody-mediated rejection, and survival rates by sensitized status with panel-reactive antibody levels <10%, 10% to 50%, and >50%, and compared these survival rates with those from the United Network for Organ Sharing database. There was no difference in 15-year survival between the 2 age groups (35±12.4% and 49±17.3%, ≥60 versus <60 years; P=0.45). There was no difference in 15-year survival between the dialysis and nondialysis groups (44±13.4% and 37±15.2%, P=0.95). Actuarial freedom from any cardiac rejection ( acute cellular rejection >0 or antibody-mediated rejection >0) was 92±2.8% and 84±3.8%, acute cellular rejection (≥2R/3A) 98±1.5% and 94±2.5%, and antibody-mediated rejection (≥1) 96±2.1% and 93±2.6% at 30 days and 1 year after HKT x. There was no difference in the 5-year survival among recipients by sensitization status with panel-reactive antibody levels <10%, 10% to 50%, and >50% (82±5.9%, 83±10.8%, and 92±8.0%; P=0.55). There was no difference in 15-year survival after HKT x between the United Network for Organ Sharing database and our center (38±3.2% and 40±10.1%, respectively; P=0.45). Conclusions HKT x is safe to perform in patients 60 years and older or younger than 60 years and with or without dialysis dependence, with excellent outcomes. The degree of panel-reactive antibody sensitization did not appear to affect survival after HKT x.

Predicted heart mass is the optimal metric for size match in heart transplantation.

BACKGROUND: Donor-recipient size match is traditionally assessed by body weight. We assessed the ability of 5 size match metrics-predicted heart mass (PHM), weight, height, body mass index (BMI) and body surface area (BSA)-to predict 1-year mortality after heart transplant and to assess the effect of size match on donor heart turn down for size. METHODS: The study cohort comprised 19,168 adult heart transplant recipients in the United Network for Organ Sharing registry between 2007 and 2016. Each size match metric was divided into 7 equally sized groups using the donor-recipient ratio for each metric. Single and multivariable Cox proportional hazard models for mortality 1 year after transplant were constructed. RESULTS: Recipients in the severely (donor-recipient PHM ratio 0.54-0.86) undersized group for PHM experienced increased mortality, with a hazard ratio of 1.34 (95% confidence interval, 1.13-1.59; p < 0.001). There was no increased risk of death at 1 year if donors were undersized for weight, height, BMI, or BSA. We found that 32% of heart offers turned down for donor size would be acceptable using a PHM threshold of 0.86 or greater and that 14% of offers accepted (most of which are female donor to male recipient) were below this threshold. CONCLUSIONS: PHM is the optimal donor-recipient size match metric for prediction of mortality after heart transplant. Many offers turned down for donor size were above the threshold for adequacy of size match by PHM identified, and thus, the use of PHM could improve donor heart utilization and post-transplant survival.

Acute Cor Pulmonale in Veno-Venous Extracorporeal Membrane Oxygenation: Three Case Reports.

A retrospective review of three patients with acute respiratory distress syndrome (ARDS) and normal baseline right ventricular function admitted to the Cardiac Surgery Intensive Care Unit whom developed acute cor pulmonale while on veno-venous extracorporeal membrane oxygenation. These patients were diagnosed with ARDS using Berlin Criteria definitions and cannulated with a dual lumen (Avalon) cannula. Despite variations in history, presentation, and course, findings of acute cor pulmonale were encountered 4 to 6 weeks after extracorporeal membrane oxygenation cannulation. The potential mechanisms include thromboembolic burden to the pulmonary vasculature, hypoxemia, acidosis, the pathologic progression of ARDS, and chronic nonphysiologic flow to the right heart.

Interagency registry for mechanically assisted circulatory support report on the total artificial heart.

BACKGROUND: We sought to better understand the patient population who receive a temporary total artificial heart (TAH) as bridge to transplant or as bridge to decision by evaluating data from the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) database. METHODS: We examined data related to survival, adverse events, and competing outcomes from patients who received TAHs between June 2006 and April 2017 and used hazard function analysis to explore risk factors for mortality. RESULTS: Data from 450 patients (87% men; mean age, 50 years) were available in the INTERMACS database. The 2 most common diagnoses were dilated cardiomyopathy (50%) and ischemic cardiomyopathy (20%). Risk factors for right heart failure were present in 82% of patients. Most patients were INTERMACS Profile 1 (43%) or 2 (37%) at implantation. There were 266 patients who eventually underwent transplantation, and 162 died. Overall 3-, 6-, and 12-month actuarial survival rates were 73%, 62%, and 53%, respectively. Risk factors for death included older age (p = 0.001), need for pre-implantation dialysis (p = 0.006), higher creatinine (p = 0.008) and lower albumin (p < 0.001) levels, and implantation at a low-volume center (≤10 TAHs; p < 0.001). Competing-outcomes analysis showed 71% of patients in high-volume centers were alive on the device or had undergone transplantation at 12 months after TAH implantation vs 57% in low-volume centers (p = 0.003). CONCLUSIONS: Patients receiving TAHs have rapidly declining cardiac function and require prompt intervention. Experienced centers have better outcomes, likely related to patient selection, timing of implantation, patient care, and device management. Organized transfer of knowledge to low-volume centers could improve outcomes.

Impact of the 80-hour workweek on surgical case exposure within a general surgery residency program.

OBJECTIVE: The objective of this statistical analysis was to test the hypothesis that implementation of the 80-hour workweek restrictions for General Surgery residents at Riverside Methodist Hospital after July 2003 decreased their operative experience relative to surgical residents trained at Riverside before these changes. DESIGN, SETTING, PARTICIPANTS: Data were collected from the Accreditation Council for Graduate Medical Education national database and from Riverside Methodist Hospital's General Surgery Residency records for a sampling of academic years before and after the duty-hour changes in surgical education (July 1, 2003). Current procedural terminology (CPT) surgical procedure codes logged by postgraduate year (PGY) 5 General Surgery residents 15 years before and 5 years after implementation of the 80-hour workweek were compared. The outcome variables "total major cases" and "Chief cases" were compared between 2 study groups defined by the time intervals exclusively before July 2003 ("pre") and inclusively after July 2003 ("post"). Hospital general surgical case volume for the study intervals was also tallied. Statistical analyses included 1- and 2-sided t-tests, nonparametric tests, and t-tests on a 3-parameter logarithmic transformation of the data. RESULTS: Despite an upward trend in total general surgery cases (slope = 25/year, p = 0.005), there was a statistically significant decrease in the operative experience for categorical surgical residents following the 80-hour workweek restrictions. The mean (SD) number of major cases performed by "pre"-restriction residents during their training significantly exceeded that of their "post" cohorts (1395 [326] vs 953 [134], p < 0.001). The training for PGY 5 residents was similarly influenced (345 [81] vs 237 [55], p < .0001). CONCLUSIONS: Despite an increase in the total number of major operative cases available, the volume of cases performed by residents has decreased after implementation of the Accreditation Council for Graduate Medical Education (ACGME) work-hour restrictions. Our data suggest that the impact of the 80-hour workweek has had a detrimental effect on the conventional resident training experience.