Background: Left ventricular assist device (LVAD) has been increasingly used in patients with advanced heart failure. This study aimed to assess the impact of implementation of LVAD therapy on heart transplantation (HTx) service in Hong Kong (HK). Methods: LVAD program was started in 2010 in HK and patients who had been put on HTx waiting list since the start of HTx program in HK from 1992 to 2020 were included for analysis. Survival on HTx waiting list between pre-LVAD era 1992-2009 and post-LVAD era 2010-2020 were analyzed by Kaplan-Meier method and compared by log-rank test. Multivariate analysis by time-dependent Cox-proportional hazard model was used to identify independent predictors of HTx waiting list mortality. Results: A total of 478 heart transplant listing episodes involving 457 patients were included for analysis.There were 232 heart transplantations (HTxs), including one re-transplantation, during the study period.There were 110 patients who received LVAD as bridge to transplantation (BTT) and 30 of them had undergone subsequent HTx. The 1-, 2-and 3-year survival on waiting list were 82.3%, 61.7% and 43.0% respectively in the pre-LVAD era (n=178), while the 1-, 2-and 3-year survival were significantly improved at 85.7%, 81.8% and 78% respectively in the post-LVAD era (n=300), (P=0.003). Time-dependent multivariate analysis revealed that LVAD support was independently associated with significant reduction of waiting list mortality [odds ratio (OR): 0.21; 95% confidence interval (CI): 0.10-0.44, P<0.001]. There was no significant difference when comparing survival after LVAD as BTT and survival after HTx up to 8 years (76.1% vs. 72% at 8 years respectively, P=0.732). Conclusions: Waiting list survival improved in the post-LVAD era driven by the implementation of LVAD service. Long-term survival for LVAD recipients as BTT were comparable to heart transplant recipients in HK.

Severe pulmonary hypertension (PH) is not common even in patients with severe chronic lung disease (CLD) but data on hemodynamic characteristics among patients with severe CLD is scarce. All adult patients who had right heart catheterization for lung transplant assessment for severe CLD in the only lung transplant service and for PAH management in the only tertiary pulmonary hypertension service in Hong Kong from 2010 to 2020 were included and classified into CLD group and PAH group. Patient characteristics and hemodynamic parameters were analyzed. There were 153 patients included with 106 patients in the CLD group and 47 in the PAH group. There were only 19.8% of the patients in the CLD group had severe pulmonary hypertension. Patients in the CLD group had significantly lower systolic pulmonary arterial pressure (PAPs), lower mean pulmonary arterial pressure (PAPm), higher cardiac index, and lower PVR when compared with the PAH group ( p < 0.001). The area under curve (AUC) of PAPs, PAPm, and PVR were excellent, 0.973, 0.970, and 0.938, respectively for discrimination between CLD and PAH on receiver operator characteristics curve analysis. Optimal cutoff values were 55.5 mmHg, 35.5 mmHg, and 6.1 Wood Units for PAPs, PAPm, and PVR with Youden Index 0.85, 0.80, and 0.82, respectively. There were distinct hemodynamic characteristics between the CLD group and the PAH group. Systolic pulmonary arterial pressure, mean pulmonary arterial pressure, and pulmonary vascular resistance are useful to discriminate between the phenotype of severe CLD and PAH.

Background:The year 2022 marks the 30th anniversary of heart transplant service in Hong Kong (HK). In this study, we describe prevailing trends and outcomes of advanced heart failure (AHF), including heart transplantations (HTx), in HK over the past 30 years. Methods: Trends in heart failure prevalence in HK from 1993 to 2021 were analyzed based on data from the Hospital Authority Clinical Data and Reporting System. All AHF patients referred for HTx consideration between 1992 and 2021 were reviewed. The bridge-to-transplant (BTT) utilization of short-term mechanical circulatory support (ST-MCS) devices, including venoarterial extracorporeal membrane oxygenation (VA-ECMO) and durable left ventricular assist devices (LVADs), from 2010 to 2021 was reviewed. Results: Overall, 237 heart transplants were performed in HK, with 10-year posttransplant and median survival of 68.1% and 18.7 years, respectively. An increase in AHF clinic referrals was correlated with increasing heart failure prevalence (R 2 =0.635, P<0.001). In total, 146 referrals were made for ST-MCS, and an observed increase in ST-MCS referrals was correlated with increasing VA-ECMO utilization (R 2 =0.849, P<0.001). Among 62 patients accepted for AHF therapy, those with durable LVAD implementation had better 1-year survival (71.5%) than those receiving an extracorporeal CentriMag (Levitronix) device as BTT (40%, P=0.008). In total, 143 LVADs were implanted, with 130 as BTT or bridge-to-candidacy (BTC) methods. The survival rate among the 130 BTT/BTC LVAD patients resembled that of HTx recipients (73.8% vs. 69.8% at 9 years, P=0.296). Conclusions: The burden of AHF management has increased and gained complexity over the past 30 years in Hong Kong.

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