Heart Kidney Research Articles

Ventricular Assist Devices Are a Viable Method to Support Patients to Multi-Organ Transplant

<h3>Purpose</h3> While ventricular assist devices (VADs) are known to improve survival in patients awaiting heart transplant, there are limited data describing the use of VADs in patients listed for multi-organ transplant or evaluating these patients' outcomes. <h3>Methods</h3> This retrospective cohort study identified patients from the UNOS database listed for heart transplant in combination with another solid organ from 2004-2019 and identified those with VADs at the time of listing and at transplant. Mortality was compared between patients with and without VAD using χ2 tests. Linear regression was used to assess changes in VAD use over time. <h3>Results</h3> Over 15 years, 22% (n=700) of heart-kidney (HK), 4% (n=20) of heart-liver (HLi), and 3% (n=25) of heart of heart-lung (HLu) patients were on VADs at listing. The median age of HK-VAD was 55y (IQR 47, 62), of HLi-VAD 52y (IQR 43, 55), and HLu-VAD 47y (IQR 33, 58). The majority of multi-organ VAD patients survived to transplant; 64% of HK-VAD, 70% of HLi-VAD, and 44% of HLu-VAD. Survival to transplant was higher in HK-VAD compared to HK-no VAD (72% vs 67%, p<0.05), while there was no difference between HLi-VAD and HLi-no VAD (80% vs 71%, p=0.38) or HLu-VAD and HLu-no VAD (52% vs 61%, p=0.37). One year post-transplant survival did not differ based on the presence of a VAD; HK-VAD (86.0%) vs HK-no VAD (88.9%) <i>p=0.11,</i> HLi-VAD (85.0%) vs HLi-no VAD (89.1%) <i>p=0.48</i>, and HLu-VAD (82.7%) vs HLu-no VAD (79.1%) <i>p=0.71.</i> <b>Figure</b> HK-VAD increased from 4 in 2004 to 94 in 2019 (<i>p for trend<0.001).</i> There were no changes over time in HLi-VAD or HLu-VAD <i>(p for both>0.05)</i>. <h3>Conclusion</h3> VADs are being used to support a substantial proportion of multi-organ patients, with an increase in patients waiting for heart-kidney transplant. The majority of these patients survive to transplant, and waitlist survival is higher in HK-VAD vs HK-no VAD. There is no difference in 1 year mortality when compared to patients without VADs, suggesting that this may be an effective support strategy for certain patients with multi-organ failure.

Association between Pulmonary Hypertension and Outcomes in Heart-Kidney Transplantation

<h3>Purpose</h3> The prevalence and severity of pulmonary hypertension (PH) in heart-kidney (HK) transplant candidates are not well-characterized. Additional hemodynamic risk factors (i.e. arteriovenous fistula for hemodialysis access, intermittent volume reduction) are present in HK patients. The current study describes PH severity in this patient population to understand its impact on post-transplant outcomes when compared to isolated heart transplant (HT) patients. <h3>Methods</h3> We searched the UNOS database to identify adult HK and HT recipients who underwent de novo transplantation between 2010-2020. Propensity score matching was used to identify a balanced cohort of HK and HT recipients. Baseline characteristics and invasive hemodynamics were compared between HT and HK. Logistic regression models were constructed to quantify the association of PH with 1-year post-transplant mortality. PH was defined as a mean PA pressure >20 mmHg using the updated hemodynamic classification. <h3>Results</h3> We identified 1392 HK recipients and propensity-matched them with 1392 HT recipients. Clinical covariates except for wait-list time and creatinine were well-balanced <b>(Table 1A).</b> PH was more frequent in HK recipients than HT although both groups had mean PVR < 3 WU. HK recipients had significantly higher pre-transplant PA and wedge pressures, but lower PVR from higher circulating cardiac output. In the propensity-matched cohort, HK recipients had numerically higher 1-year mortality (11.2% vs. 8.5%, p=0.02). Multivariate logistic regression analysis identified PH (OR: 1.89 [1.22 - 2.92], p=0.004)<b>,</b> as an independent predictor of 1-year post-transplant mortality for both HT and HK, with HK PH patients experiencing worse outcomes <b>(Figure 1).</b> <h3>Conclusion</h3> HK recipients have greater PH severity and post-transplant mortality risk when compared with matched HT recipients. Further studies are warranted to better understand PH mechanisms and outcomes in the dual-organ populations.

Characteristics and Outcomes of Patients Undergoing Combined Organ Transplantation (from the United Network for Organ Sharing)

Studies have shown that highly selected patients who underwent combined heart-kidney (HK) and heart-liver transplants (HLv) have short- and long-term outcomes comparable to those observed in primary heart transplantation (HT). Adults patients with stage D heart failure that underwent combined HK, HLv, and heart-lung (HL) were identified in the United Network for Organ Sharing registry from 1991 to 2016, with follow-up through March 2018. We conducted inverse probability of treatment weighting survival analysis of long-term survival stratified by type of combined organ transplant, accounting for donor, recipient, and operative characteristics. We identified 2,300 patients who underwent combined organ transplant (HK 1,257, HLv 212, HL 831). HL recipients were more likely white (77%), women (58%), with congenital heart disease (44.5%), and longer waiting list time (median 195 days). HK transplant increased significantly during the study period where as HL decreased significantly. Median survival was 12.2 years for HK (95% confidence intervals [CI] 10.8 to 12.8), 12 for HLv (95% CI 8.6 to 17.6) but significantly lower at 4.5 years for HL (95% CI 3.6 to 5.8). Combined HK and HLv transplantation rates are increasing and long-term survival is comparable to primary HT, unlike HL which is associated with decreasing trends and significantly lower survival.

Temporal Trends and Outcomes of Patients Undergoing Combined Organ Transplantation: Insights from the United Network for Organ Sharing (UNOS)

Studies have shown that highly selected patients undergoing combined heart-kidney (HK) and heart-liver transplants (HL) have short- and long-term outcomes comparable to those observed in primary heart transplantation (HT). Adults patients with stage D heart failure that underwent combined HK, HLv and heart-lung (HL) were identified in the United Network for Organ Sharing (UNOS) registry between 1991 and 2016, with follow-up through March 2018. We conducted inverse-probability weighted estimator (IPWE) survival analysis of long-term survival stratified by type of combined organ transplant, accounting for donor, recipient and operative characteristics. We identified 2300 patients who underwent combined organ transplant (HK: 1,257, HLv: 212, HL: 831). HL recipients were more likely white (77%), females (58%), with congenital heart disease (44.5%), and longer waiting list time (median 195 days). HK transplant increased significantly during the study period where as HL decreased significantly (Figure). Median survival was 12.2 years for HK (95% Confidence intervals [CI], 10.8-12.8), 12 for HLv (95% CI 8.6-17.6) but significantly lower at 4.5 years for HL (95% CI 3.6-5.8) (Figure). Combined HK and HLv transplantation rates are increasing and long-term survival is comparable to primary HT, unlike HL which is associated with decreasing trends and significantly lower survival.

Multi-organ Transplantation: Is There a Protective Effect Against Acute and Chronic Rejection?

Heart-lung transplantation (Tx) is known to offer a protective effect against acute cardiac rejection. This study was undertaken to evaluate acute and chronic heart and/or lung rejection in the setting of multiple-transplanted organs from the same donor compared with single-organ transplantation. Acute (treated rejection episodes of heart or lungs) and chronic (allograft vasculopathy in hearts and bronchiolitis obliterans syndrome [BOS] in lungs) rejection events were analyzed in 348 heart transplant (H) recipients, 24 heart-lung (HL) recipients, 82 double-lung (L) recipients and 8 heart-kidney (HK) recipients >18 years of age, who were transplanted between 1990 and 2002. Survival at 3 years differed among groups as follows: HK, 100%; H, 82%; HL, 74%; and L, 70%. The probability of acute rejection within the first 3 months was higher in H recipients than in HL (81% vs 22%; p < 0.0001) or HK (81% vs 12%; p = 0.00009) recipients. Acute cardiac rejection occurred more frequently during the first 2 years in isolated H recipients compared with HL (2.8 vs 0.27 episodes; p < 0.0001) and HK (2.8 vs 0.54; p < 0.001) recipients. Acute lung rejection occurred more frequently in the first 2 years in L than HL (2.4 vs 1.0 episodes; p = 0.02) recipients. Chronic cardiac rejection (allograft vasculopathy) was more likely within 3 years after H compared with HL (32% vs 16%; p = 0.04) or HK (32% vs 0%; p = 0.14). The onset of chronic lung rejection (BOS) within 3 years was similar in HL and L recipients (39% vs 40%; p = 0.9). Recipients of multiple organs from a single donor undergo less acute rejection of the heart or lungs compared with isolated heart or lung transplant recipients. Cardiac allograft vasculopathy is decreased significantly when cardiac transplantation is combined with a lung allograft. A lower incidence of cardiac allograft vasculopathy is observed when cardiac transplantation is combined with a renal allograft, and may prove statistically significant when more cases have been accumulated. These phenomena may result from immune modulation of the recipient by simultaneous transplant of disparate tissues or introduction of immune-modulating hematopoietic elements.