Comparative Outcomes of Surgical and Transcatheter Aortic Valve Replacement: A Meta-analysis and Parametric Extrapolation of Clinical Trials.

INTRODUCTION: We aimed to pool randomized clinical trials (RCTs) comparing surgical aortic valve replacement (SAVR) with transcatheter aortic valve replacement (TAVR) and extrapolate pooled time-to-event data to compare long-term outcomes. METHODS: An electronic database search was performed for RCTs comparing SAVR with TAVR. The most current longest follow-up data for each RCT were included. Data were pooled using a random-effects model. Survival data were pooled for Kaplan-Meier analysis as well as parametric modeling with extrapolation. RESULTS: Seven RCTs comprising 7774 patients were included. Mean valve gradient at 5 y was comparable between SAVR [11 mmHg (3.7; 18.3)] and TAVR [8.1 mmHg (1.9; 14.3)] (P = 0.38). TAVR had a higher mean valve area at 30 d, 1 y, and 2 y [1.68 cm2 (1.22; 2.13) versus 1.8 cm2 (1.35; 2.25), P = 0.02]. SAVR had a higher freedom from any paravalvular leak at 30 d and 1 y [86% (81; 90) versus 39% (36; 41), P < 0.01]. All-cause death was lower in the SAVR group at 5 y [39% (29; 50) versus 43% (31; 57), P < 0.01]. Although no differences were seen between SAVR and TAVR in the pooled Kaplan-Meier analysis of all-cause mortality and composite of all-cause mortality or stroke, parametric modeling with extrapolation showed significant divergence for both outcomes. CONCLUSIONS: Pooled all-cause mortality as well as pooled composite of all-cause mortality or stroke indicated better survival with SAVR at 5 y. Long-term parametric extrapolation also indicated superior survival with SAVR.

Organ Donation by the Imminently Dead: Addressing the Organ Shortage and the Dead Donor Rule.

The dead donor rule (DDR) has facilitated the saving of hundreds of thousands of lives. Recent advances in heart donation, however, have exposed how DDR has limited donation of all organs. We propose advancing the moment in the dying process at which death can be determined to increase substantially the supply of organs for transplantation. We justify this approach by identifying certain flaws in the Uniform Determination of Death Act and proposing a modification of that law that permits earlier procurement of healthier organs in greater numbers.

Characterizing Adaptive Changes and Patient Survival After 2018 Donor Allocation Restructuring: A UNOS Database Analysis.

PURPOSE: We sought to characterize adaptive changes to the revised United Network for Organ Sharing donor heart allocation policy and estimate long-term survival trends for heart transplant (HTx) recipients. METHODS: Patients listed for HTx between October 17, 2013 and September 30, 2021 were identified from the United Network for Organ Sharing database, and stratified into pre- and postpolicy revision groups. Subanalyses were performed to examine trends in device utilization for extracorporeal membranous oxygenation (ECMO), durable left ventricular assist device (LVAD), intra-aortic balloon pump (IABP), microaxial support (Impella), and no mechanical circulatory support (non-MCS). Survival data post-HTx were fitted to parametric distributions and extrapolated to 5 years. RESULTS: We identified 27,523 HTx waitlist candidates during the study period, most of whom (n = 16,376) were waitlisted in the prepolicy change period. Overall, 19,554 patients underwent HTx during the study period (pre: 12,037 and post: 7517). Listings increased after the policy change for ECMO ( P < 0.01), Impella ( P < 0.01), and IABP ( P < 0.01) patients. Listings for LVAD ( P < 0.01) and non-MCS ( P < 0.01) patients decreased. HTx increased for ECMO ( P < 0.01), Impella ( P < 0.01), and IABP ( P < 0.01) patients after the policy change and decreased for LVAD ( P < 0.01) and non-MCS ( P < 0.01) patients. Waitlist survival increased for the overall ( P < 0.01), ECMO ( P < 0.01), IABP ( P < 0.01), and non-MCS ( P < 0.01) groups. Waitlist survival did not differ for the LVAD ( P = 0.8) and Impella ( P = 0.1) groups. Post-transplant survival decreased for the overall ( P < 0.01), LVAD ( P < 0.01), and non-MCS ( P < 0.01) populations. CONCLUSIONS: Allocation policy revisions have contributed to greater utilization of ECMO, Impella, and IABP, decreased utilization of LVADs and non-MCS, increased waitlist survival, and decreased post-HTx survival.

Outcomes of outflow graft stenting in HeartMate 3 left ventricular assist devices: A systematic review and individual patient data meta-analysis.

PURPOSE: LVAD outflow graft stenosis continues to remain prevalent with a high complication rate. We sought to pool the existing evidence on indications, utilization patterns, and outcomes of transcatheter interventions for outflow graft stenosis in the HeartMate 3 LVAD. METHODS: An electronic search was performed to identify all studies in the English literature reporting on HeartMate 3 LVAD outflow graft stenting. Patient-level data were extracted for analysis. RESULTS: Thirteen published reports and one unpublished case comprising a total of 28 patients were included. Median patient age was 68.5 years [Interquartile range: 58, 71] and 25.9% (7/27) were female. Dyspnea [60.7% (17/28)] was the most common presenting symptom. Low flow alarms were present in 60% (15/25) of patients. Findings included external compression [35.7% (10/28)], graft twist [21.4% (6/28)], graft twist and external compression [14.3% (4.28)], intraluminal thrombus [10.7% (3/28)], graft twist and intraluminal thrombus [3.6% (1/28)], and pseudoaneurysm of outflow graft [3.6% (1/28)]. Median time from LVAD implantation to stenting was 2.1 years [1.4, 3]. Immediate flow normalization after stenting was observed in 85.7% (24/28). The 30-day mortality was 12% (3/25). Overall mortality was 12% (3/25) at a median follow-up of 3.9 months [1, 17]. CONCLUSION: Outflow graft stenting in the HeartMate 3 LVAD appears to be a reasonable treatment option for outflow graft stenosis, with low overall rates of complications and mortality. Further refinement of indications and approaches may improve outcomes.

Summary of a consensus conference on heart-liver transplantation.

Patients with severe heart disease may have coexisting liver disease from various causes. The incidence of combined heart-liver transplant (CHLT) is increasing as more patients with congenital heart disease survive to adulthood and develop advanced heart failure with associated liver disease from chronic right-sided heart or Fontan failure. However, the criteria for CHLT have not been established. To address this unmet need, a virtual consensus conference was organized on June 10, 2022, endorsed by the American Society of Transplantation. The conference represented a collaborative effort by experts in cardiothoracic and liver transplantation from across the United States to assess interdisciplinary criteria for liver transplantation in the CHLT candidate, surgical considerations of CHLT, current allocation system that generally results in the liver following the heart for CHLT, and optimal post-CHLT management. The conference served as a forum to unify criteria between the different specialties and to forge a pathway for patients who may need dual organ transplantation. Due to the continuing shortage of available donor organs, ethical issues related to multiorgan transplantation were also debated. The findings and consensus statements are presented.

Predicted heart mass based on ideal body weight for donor-to-recipient size matching.

BACKGROUND: Predicted heart mass (PHM) is a commonly used tool for donor-to-recipient size matching. However, incorporating body weight as part of PHM can be considered problematic given its high variability, and low metabolic nature of fat. We sought to assess whether substituting the actual donor and recipient weight with the ideal body weight (IBW) would affect the association of donor-to-recipient PHM ratio with 1-year and overall survival after heart transplantation. METHODS: The United Network for Organ Sharing (UNOS) database was queried for adult patients who received a primary heart transplant between January 2000 and September 2021. RESULTS: Both PHM and ideal PHM (IPHM) ratios were associated with one-year (PHM: p = .003; IPHM: p = .0007) and overall (PHM: p = .02; IPHM: p = .02) survival. In the continuous analysis with restricted cubic splines, both PHM (p = .0003) and IPHM (p = .00001) were associated with relative hazards of death. CONCLUSION: IPHM is significantly associated with post-transplant survival and may be a useful compliment to PHM.

Utilization and outcomes of V-AV ECMO: A systematic review and meta-analysis.

BACKGROUND: Veno-arterial-venous extracorporeal membrane oxygenation (V-AV ECMO) is a less commonly used configuration of ECMO. We sought to understand the indications, utilization patterns, and outcomes of V-AV ECMO by quantitatively pooling the existing evidence from the literature. METHODS: Electronic search was performed to identify all relevant studies reporting V-AV ECMO usage. Five studies comprising 77 patients were selected and cohort-level data were extracted for further analysis. RESULTS: Mean patient age was 61 (95% CI: 55.2, 66.5) years and 30% (23/77) were female. The majority of cases [91% (70/77)] were transitioned to V-AV ECMO from another pre-existing ECMO configuration: V-A ECMO in 55% (42/77) vs. V-V ECMO in 36% (28/77), p = 0.04. Only 9% (7/77) of cases were directly placed on V-AV ECMO. The mean duration of hospital stay was 42.3 (95% CI: 10.5, 74.2) days, while ICU mortality was 46% (29, 64). Transition to durable left ventricular assist device was performed in 3% (2/64) of patients, while 3% (2/64) underwent heart transplantation. V-AV ECMO was successfully weaned to explantation in 33% (21/64) of patients. CONCLUSION: V-AV ECMO is a viable option for optimizing cardiopulmonary support in selected patients. Survival to weaning or bridging therapy appears comparable to more common ECMO configurations.

Ultrasonic scalpel versus electrocautery for internal mammary artery harvesting: a meta-analysis.

OBJECTIVE: Although an ultrasonic harmonic scalpel (HS) has been used to harvest the internal mammary artery (IMA) for coronary artery bypass grafting, the benefits and risks compared to conventional electrocautery (EC) are not clear. We aimed to compare the outcomes of HS versus EC for IMA harvesting. METHODS: An electronic search was performed to identify all relevant studies. Baseline characteristics, perioperative variables, and clinical outcomes were extracted and pooled for meta-analysis. RESULTS: This meta-analysis included 12 studies. Pooled analyses demonstrated that both groups had comparable preoperative baseline characteristics including age, gender, and left ventricular ejection fraction. HS included more diabetic patients [33% (95% CI 30, 35) vs. 27% (23, 31), p = 0.01]. Harvest time for unilateral IMA was significantly longer with HS than EC [39 (31, 47) minutes vs. 25 (17, 33) minutes, p < 0.01]. However, the rate of pedicled unilateral IMA was significantly higher for EC compared with HS [20% (17, 24) vs. 8% (7, 9), p < 0.01]. The rate of intact endothelium was significantly higher with HS than EC [95% (88, 98) vs. 81% (68, 89), p < 0.01). There was no significant difference in postoperative outcomes including bleeding [3% (2, 4)], sternal infection [3% (2, 4)], and operative/30-day mortality [3% (2, 4)]. CONCLUSIONS: HS required longer IMA harvest times which could be partially attributed to a higher skeletonization rate in this category. HS may cause less endothelial injury than EC; however, no significant differences in postoperative outcomes were seen between the groups.

Association of Heart Transplant Volume with Presence of Lung Transplant Programs and Heart Transplant's SRTR One-year Survival Rating.

BACKGROUND: Several factors affect heart transplant (HTx) and lung transplant (LTx) program outcomes. Variabilities in institutional and community characteristics have been shown to influence survival. At present, half of HTx centers in the United States do not possess a concomitant LTx program. This study sought to better understand the characteristics of HTx with and without LTx programs. METHODS: Nationwide transplant data were collected from the Scientific Registry of Transplant Recipients (SRTR) in August 2020. SRTR star rating ranges from tier 1 (lowest) to tier 5 (highest). HTx volumes and SRTR star ratings for survival were compared between the centers with heart-only (H0) programs and the centers with heart-lung (HL) programs. RESULTS: SRTR star ratings were available for 117 transplant centers with one or more HTx reported. The median number of HTx performed over 1 year was 16 (interquartile range [IQR]: 2-29). The number of HL centers (n = 67, 57.3%) were comparable to H0 centers (n = 50, 42.7%; p = 0.14). The HTx volume at the HL centers (28 [IQR: 17-41]) exceeded the HTx volume at the H0 centers (13 [IQR: 9-23]; p < 0.01), but were comparable to the LTx volume at the HL centers (31 [IQR: 16-46]; p = 0.25). The median HTx one-year survival rating was 3 (IQR: 2-4) at both the H0 and HL centers (p = 0.85). The HTx and LTx volumes were positively associated with the respective 1-year survivals (p < 0.01). CONCLUSION: While the presence of an LTx program is not directly associated with HTx survival, it has a positive association with the HTx volume. The HTx and LTx volumes are positively associated with the 1-year survival.

Utility of Recipient Cardiothoracic Ratio in Predicting Delayed Chest Closure after Heart Transplantation.

BACKGROUND: Predicted cardiac mass (PCM) has been well validated for size matching donor hearts to heart transplantation recipients. We hypothesized that cardiothoracic ratio (CTR) could be reflective of recipient-specific limits of oversizing, and sought to determine the utility of donor to recipient PCM ratio (PCMR) and CTR in predicting delayed chest closure after heart transplantation. METHODS: A retrospective review of prospectively collected data on 38 consecutive heart transplantations performed at our institution from 2017 to 2020 was performed. Donor and recipient PCM were estimated using Multi-Ethnic Study of Atherosclerosis predictive models. Receiver operating characteristic analysis was performed to determine the discriminatory power of the ratio of PCMR to CTR in predicting delayed sternal closure. RESULTS: Of the 38 patients, 71.1% (27/38) were male and the median age at transplantation was 58 (interquartile range [IQR]: 47-62) years. Ischemic cardiomyopathy was present in 31.6% of recipients (12/38). Median recipient CTR was 0.63 [IQR: 0.59-0.66]. Median donor to recipient PCMR was 1.07 [IQR: 0.96-1.19], which indicated 7% oversizing. Thirteen out of 38 (34.2%) underwent delayed sternal closure. Primary graft dysfunction occurred in 15.8% (6/38). PCMR/CTR showed good discriminatory power in predicting delayed sternal closure [area under the curve: 80.4% (65.3-95.6%)]. PCMR/CTR cut-off of 1.7 offered the best trade-off between the sensitivity (69.6%) and specificity (91.7%). CONCLUSION: CTR could be helpful in guiding the recipient-specific extent of oversizing donor hearts. Maintaining the ratio of PCMR to CTR below 1.7 could avoid excessive oversizing of the donor heart.

Microaxial circulatory support for percutaneous coronary intervention: A systematic review and meta-analysis.

BACKGROUND: Microaxial circulatory support devices have been used to support patients treated with percutaneous coronary intervention (PCI) for acute myocardial infarction complicated by cardiogenic shock (AMICS). The purpose of this systematic review and meta-analysis was to pool and analyze the existing evidence on the baseline characteristics, periprocedural data, and outcomes of microaxial support before and after PCI in AMICS. METHODS: An electronic database search was performed to identify all cohort studies on Impella and PCI for cardiogenic shock in the English language. A total of five articles comprising 543 patients were included. These patients received microaxial support either before (pre-PCI) or after (post-PCI) undergoing PCI. Comparative analyses were done between both groups. RESULTS: The mean patient age was 66 years [95% Confidence Interval (58-74)], and 22% (89/396) of patients were female. ST-elevation myocardial infarctions (MI) comprised 64% (44-80) of MIs and 50% (44-56) of MIs involved the left anterior descending artery. The mean number of diseased vessels was 2.21 (1.62-2.80). The mean left ventricular ejection fraction was 31% (23.4-38.6). The mean arterial pressure was 66.3 mm Hg (54.1-78.5). Mean serum lactate [6.1 mmol/L (3.3-8.9)] and serum creatinine [1.4 mg/dl (1.0-1.7)] were similar between groups. 30-day mortality was lower in the pre-PCI group [41% (34%-49%)] compared to the post-PCI group [61% (42%-77%), p < 0.01]. Pooled Kaplan-Meier analysis showed better early survival in the pre-PCI group (p < 0.001). CONCLUSION: Patients presenting with AMICS were similar at baseline in both pre-PCI and post-PCI groups. Nevertheless, pre-PCI group showed better early survival compared to post-PCI group.

Clinical xenotransplantation seems close: Ethical issues persist.

Scientific barriers that have prevented successful xenotransplantation are being breached, yet many ethical issues remain. Some are broad issues that accompany the adoption of novel and expensive technologies, and some are unique to xenotransplantation. Major ethical questions include areas such as: viral transmission; zoonoses and lifetime surveillance; interfering with nature; efficacy, access, and expense; treatment of animals; regulation and oversight.