Milano, Carmelo A.

BACKGROUND: A preservation system, the Organ Care System (OCS; TransMedics) uses normothermic pulsatile perfusion during organ transport for heart transplantation. This system has demonstrated favorable outcomes in hearts recovered from extended-criteria donors after brain death (DBD) and donors after circulatory death (DCD). METHODS: The OCS Heart Perfusion Registry collects data on US heart transplantations using the OCS, static cold storage (SCS), or thoracoabdominal normothermic regional perfusion (NRP) and donor hearts recovered from DBD or DCD donors. We analyzed donor and recipient characteristics and posttransplantation outcomes in patients transplanted with OCS donor hearts (either DBD or DCD) compared with SCS hearts, and with OCS hearts from DCD donors compared with those recovered with NRP followed by SCS. Propensity score matching was used in survival analyses to adjust for differences among recipient characteristics. RESULTS: Between 2021 and 2023, 3225 consecutive heart transplantations enrolled from 56 centers were analyzed in the Heart Perfusion Registry. The OCS was used in 854 of 3225 heart transplantations (26.4%), among which 340 (39.8%) were DBD and 514 (60.2%) were DCD donors, whereas 2174 DBD donors were recovered with SCS and another 197 DCD donors with NRP techniques. The OCS-DBD group experienced a greater number of organ offer refusals before final acceptance (13 versus 6; Wilcoxon rank sum, P <0.001) and a longer transport distance (667 miles versus 232 miles; Wilcoxon rank sum, P <0.001) compared with SCS-DBD. Survival at 12 months was similar between the 2 groups (89.9% for OCS-DBD versus 90.6% for SCS-DBD; marginal Cox model, P =0.54). Among the OCS-DCD and SCS-DBD groups, survival at 12 months was also similar (91.0% versus 92.5%, respectively; marginal Cox model, P =0.32). The OCS-DCD and NRP-DCD groups demonstrated similar survival (91.0% versus 91.7%, respectively; log rank, P =0.63), although the transport distance was longer in OCS-DCD compared with DCD with NRP followed by SCS (400 miles versus 223 miles; Wilcoxon rank sum, P <0.001). By 2023, 90% of all OCS donor management and recovery was performed with dedicated organ recovery teams. CONCLUSIONS: We demonstrate that real-world implementation of the OCS for DBD donors (using predominantly a dedicated recovery team) is associated with expanded donor criteria, longer transport distance, and excellent posttransplantation outcomes. In OCS-DCD donors, outcomes parallel those of donors recovered with NRP-DCD and compare favorably with DBD donor organs.

AbstractBackgroundAs heart transplant guidelines evolve, the clinical indication for 73% of durable left ventricular assist device (LVAD) implants is now destination therapy. Although completely magnetically levitated LVAD devices have demonstrated improved durability relative to previous models, LVAD replacement procedures are still required for a variety of indications. Thus, the population of patients with a replaced LVAD is growing. There is a paucity of data regarding the outcomes and risk factors for those patients receiving first‐time LVAD replacements.MethodsThe study cohort consisted of all consecutive patients between 2006 and 2020 that received a first‐time LVAD replacement at a single institution. Preoperative clinical and laboratory variables were collected retrospectively. The primary endpoint was death or need for an additional LVAD replacement. Data were subjected to Kaplan–Meier, univariate, and multivariate Cox hazard ratio analyses.ResultsIn total, 152 patients were included in the study, of which 101 experienced the primary endpoint. On multivariate analysis, patients receiving HeartMate 3 (HM3) LVADs as the replacement device showed superior outcomes (HR 0.15, 95% CI 0.065–0.35, p < 0.0001). Independent risk factors for death or need for additional replacement included preoperative extracorporeal membrane oxygenation (ECMO) (HR 4.44, 95% CI 1.87–14.45, and p = 0.00042), increased number of sternotomies (HR 5.20, 95% CI 1.87–14.45, and p = 0.0016), and preoperative mechanical ventilation (HR 1.98, 95% CI 1.01–3.86, and p = 0.045).ConclusionsReplacement with HM3 showed superior outcomes compared to all other pump types when controlling for both initial pump type and other independent predictors of death or LVAD replacement. Preoperative ECMO, mechanical ventilation, and multiple sternotomies also increased the odds for death or the need for subsequent replacement.

Abstract Abstract 2273 Background: Continuous flow left ventricular assist device (CF-LVAD) recipients have high tendency of post-surgical gastrointestinal (GI) bleeding. We previously described the loss of high molecular weight VWF multimers (HMWM), due to either an accelerated clearance or enhanced cleavage of the HMWM, in most CF-LVAD recipients (Ann Thorac Surg. 90:1263–9). However, besides the tedious plasma VWF multimer analysis, neither VWF ristocetin cofactor nor collagen binding activity assay provides sufficient sensitivity for detecting such an acquired VWF abnormality (AVWA). In this study, we examined a new automated latex particle-enhanced immunoturbidimetric VWF activity assay (VWF:Lx) for its ability of detecting CF-LVAD-AVWA. We also analyzed the VWF pro-peptide (VWF:pp) to explored the potential mechanism of CF-LVAD-AVWA. Design: As part of an on-going prospective multicenter study, pre- and post-CF-LVAD implantation (7, 30 days and 5–7 months) blood samples were collected from 15 LVAD recipients (median age 52 years; 10 male and 5 female; 2008∼2009). Plasma VWF antigen (VWF:Ag), VWF:Lx activity, VWF:pp/Ag ratios were measured; and plasma VWF multimer analyses were performed on all available plasma samples. Standard statistical analyses were employed. Result: Loss of VWF HMWM was observed in 3 patients prior to CF-LVAD implantation and virtually all patients after surgery. VWF:Ag, VWF:Lx or VWF:pp/Ag ratios of the pre- and post-implantation samples were not significantly different (P> 0.1). However, VWF:Lx/Ag ratios of the post-implantation samples were significantly decreased (P<0.05). At a cut off of 0.8, the VWF:Lx/Ag ratio has a 90% sensitivity and specificity for detecting AVWA. Conclusions: VWF:Lx/Ag ratio has excellent sensitivity and specificity in detecting CF-LVAD-AVWA, and its impact on predicting post-surgical bleeding tendency in CF-LVAD recipients is being investigated. The distinct CF-LVAD-AVWA is most likely caused by enhanced cleavage, rather than clearance, of the HMWM. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 1122 Background: Continuous flow left ventricular assist device (CF-LVAD) recipients have increased tendency of post-surgical bleeding. We have previously described a universal loss of high molecular weight VWF multimers (HMWM), likely due to enhanced cleavage of the HMWM in CF-LVAD recipients. Among various VWF laboratory tests, VWF multimer analysis remains the reference method for detecting such an acquired VWF abnormality (AVWA). We hypothesize that the severity of AVWA is a predictor for bleeding tendency. In this study, using our in-gel VWF multimer electrophoresis method, we measured the severity of HMWM loss in CF-LVAD recipients by infra-red densitometry analysis and examined its association with other VWF activity test results and patients' bleeding tendency. Design: As part of an on-going prospective multicenter study, pre- and/or post-CF-LVAD implantation (7, 30 days and 5–7 months) blood samples were collected from 20 LVAD recipients during 2008 and 2009. Their clinically significant bleeding episodes were recorded. Plasma VWF antigen (VWF:Ag), VWF:Lx activity [Chen D, et al. J Thromb Haemost. 2011;9(10):1993–2002] and plasma VWF multimer analyses [Pruthi RK, et al. Thromb Res. 2010;126(6):543–9] were performed on all available plasma samples. VWF multimers were quantified by infra-red fluorescent densitometry analysis using Odyssey Infrared Imager version 2.0. VWF:multi ratio defined by density ratio between the high molecular weight multimer (HMWM, bands 11 and above) and low and intermediate molecular weight multimer (band 2 to 9) was calculated. Normal range of VWF:multi ratio was determined from 16 normal donor plasma and 4 pooled normal plasma. Statistical analyses including t-test and kappa test were employed. Result: The normal range of VWF:multi ratio is 0.4–0.76. The CV of VWF:multi ratio of a pooled normal plasma tested in 21 gel runs is 12%. Loss of VWF HMWM is present in three patients before CF-LVAD implantation and all patients after implantation. All samples with loss of HMWM show decreased VWF:multi ratio (<0.4). At a cut-off value of 0.4, the sensitivity and specificity of VWF:multi ratio for detecting HMWM loss are 100% and 95.5% respectively (n=67). Decrease of VWF:multi ratio is observed after implantation (0.41±0.07 pre- vs. 0.29±0.07 post-implantation, P<0.00001). In four patients who received heart transplantation, normalization of VWF multimer pattern and VWF:multi ratio (0.54±0.06) is observed. Ten patients had significant post-implantation bleeding episodes that are associated with significantly decreased VWF:multi ratio (0.26±0.04 bleeding vs. 0.32±0.09 non-bleeding, P=0.002) and VWF Lx/Ag ratio (0.72±0.10 bleeding vs 0.80±0.09 non-bleeding, P=0.001). At a cut-off of 0.26, VWF:multi ratio demonstrates a sensitivity of 64% and specificity of 85.7% for predicting clinically significant bleeding. The VWF:multi ratio shows moderate agreement with VWF:Lx/Ag ratio (Kappa value 0.42). Conclusions: Severity of VWF HMWM losses can be quantitatively measured by the new in-gel infra-red densitometry method (VWF:multi ratio). Severity of VWF HMWM losses defined by the VWF:multi ratios, along with VWF:Lx/Ag ratios are significantly associated with bleeding tendency in LVAD recipients. Disclosures: Milano: Thoratec: Consultancy.

Abstract Aims We sought to evaluate associations between baseline sphericity index (SI) and clinical outcome, and changes in SI after coronary artery bypass graft (CABG) surgery with or without surgical ventricular reconstruction (SVR) in ischaemic cardiomyopathy patients enrolled in the SVR study (Hypothesis 2) of the Surgical Treatment for Ischemic Heart Failure (STICH) trial. Methods and results Among 1000 patients in the STICH SVR study, we evaluated 546 patients (255 randomized to CABG alone and 291 to CABG + SVR) whose baseline SI values were available. SI was not significantly different between treatment groups at baseline. After 4 months, SI had increased in the CABG + SVR group, but was unchanged in the CABG alone group (0.69 ± 0.10 to 0.77 ± 0.12 vs. 0.67 ± 0.07 to 0.66 ± 0.09, respectively; P &lt; 0.001). SI did not significantly change from 4 months to 2 years in either group. Although LV end-systolic volume and EF improved significantly more in the CABG + SVR group compared with CABG alone, the severity of mitral regurgitation significantly improved only in the CABG alone group, and the estimated LV filling pressure (E/A ratio) increased only in the CABG + SVR group. Higher baseline SI was associated with worse survival after surgery (hazard ratio 1.21, 95% confidence interval 1.02 − 1.43; P = 0.026). Survival was not significantly different by treatment strategy. Conclusion Although SVR was designed to improve LV geometry, SI worsened after SVR despite improved LVEF and smaller LV volume. Survival was significantly better in patients with lower SI regardless of treatment strategy.

Abstract Transmission of pathogens from donor to recipient is a potential complication of organ transplantation. Herein, we describe the clinical course and outcomes of 4 transplant recipients who received tissues from a donor with multi‐organ infection with Klebsiella pneumoniae carbapenemase ( KPC )‐producing K. pneumoniae . Recipient 1 underwent simultaneous liver and kidney transplantation for alpha‐1 antitrypsin deficiency and alcohol‐related cirrhosis, and acute tubular necrosis, respectively. Soon after transplantation, he developed an infected hematoma and peritonitis due to KPC ‐producing K. pneumoniae despite receiving tigecycline prophylaxis. He was treated with a prolonged course of tigecycline, amikacin, and meropenem, in conjunction with surgical evacuation and percutaneous drainage of the infected fluid collections. Recipient 2 underwent living‐donor liver transplantation for cholangiocarcinoma and primary sclerosing cholangitis using vein graft from the donor infected with KPC ‐producing K. pneumoniae . Culture of the preservation fluid containing the vein graft was positive for KPC ‐producing K. pneumoniae . The patient received preemptive amikacin and tigecycline, and he did not develop any infection (as evidenced by negative surveillance blood cultures). The isolates from the donor and Recipients 1 and 2 were indistinguishable by pulsed‐field gel electrophoresis. Recipients 3 and 4 underwent kidney and heart transplantation, respectively; both patients received perioperative tigecycline prophylaxis and did not develop infections due to KPC ‐producing K. pneumoniae . All transplant recipients had good short‐term outcomes. These cases highlight the importance of inter‐institutional communication and collaboration to ensure the successful management of recipients of organs from donors infected with multidrug‐resistant organisms.