Report from a consensus conference on primary graft dysfunction after cardiac transplantation

Elevated Cardiac Troponin I in Preservation Solution Is Associated With Primary Graft Dysfunction

BACKGROUND

Although primary graft dysfunction (PGD) is a leading cause of mortality and morbidity early post-heart transplant, relatively little is known regarding mechanisms involved in PGD development.

METHODS AND RESULTS

We examined the relationship between cardiac troponin I (cTnI) concentrations in the preservation solution from 43 heart transplant procedures and the development of PGD. Donor hearts were flushed with cold preservation solution (University of Wisconsin [UW] or Custodiol) and stored in the same solution. cTnI concentrations were measured utilizing the i-STAT System and normalized to left ventricular mass. Recipient medical records were reviewed to determine PGD according to the 2014 ISHLT consensus conference. Nineteen patients developed PGD following cardiac transplantation. For both UW and Custodiol, normalized cTnI levels were significantly increased (P = .031 and .034, respectively) for those cases that developed PGD versus no PGD. cTnI levels correlated with duration of ischemic time in the UW group, but not for the Custodiol group. Donor age and donor cTnI (obtained prior to organ procurement) did not correlate with preservation cTnI levels in either UW or Custodiol.

CONCLUSIONS

Increased preservation solution cTnI is associated with the development of PGD suggesting preservation injury may be a dominant mechanism for the development of PGD.

Experience of ECMO in primary graft dysfunction after orthotopic heart transplantation

BACKGROUND

Primary graft dysfunction is the main cause of early mortality after heart transplantation. Mechanical circulatory support has been used to treat this syndrome.

OBJECTIVE

Describe the experience with extracorporeal membrane oxygenation to treat post-transplant primary cardiac graft dysfunction.

METHODS

Between January 2007 and December 2013, a total of 71 orthotopic heart transplantations were performed in patients with advanced heart failure. Eleven (15.5%) of these patients who presented primary graft dysfunction constituted the population of this study. Primary graft dysfunction manifested in our population as failure to wean from cardiopulmonary bypass in six (54.5%) patients, severe hemodynamic instability in the immediate postoperative period with severe cardiac dysfunction in three (27.3%), and cardiac arrest (18.2%). The average ischemia time was 151 ± 82 minutes. Once the diagnosis of primary graft dysfunction was established, we installed a mechanical circulatory support to stabilize the severe hemodynamic condition of the patients and followed their progression longitudinally.

RESULTS

The average duration of extracorporeal membrane oxygenation support was 76 ± 47.4 hours (range 32 to 144 hours). Weaning with cardiac recovery was successful in nine (81.8%) patients. However, two patients who presented cardiac recovery did not survive to hospital discharge.

CONCLUSION

Mechanical circulatory support with central extracorporeal membrane oxygenation promoted cardiac recovery within a few days in most patients.

Cardiac mechanics in heart transplant recipients with and without transplant vasculopathy

Evaluation of cardiac mechanics in heart transplant recipients (HTR) is of paramount importance. Assessment of strain through echocardiography is suited to describe cardiac function and might allow characterizing patients with and without transplant vasculopathy (TVP) a risk factor of impaired organ function and rejection. For this study 41 HTR immediately after and 1-3 years after transplantation were examined in a retrospective approach with 2-dimensional speckle tracking echocardiography to assess longitudinal, radial and circumferential strain and strain rate. The cohort consists of 33 men and 8 women with a median age of 54 years (1st, 3rd; 45.7, 65.3) with seven cases diagnosed with TVP during follow-up, as diagnosed by coronary angiography. The overall cohort showed an improvement of global longitudinal strain from baseline to 1 and 3 years with -14.2% (-16.9, -12.3%) to -16.1% (-17.5, -14.3%) and -16.7% (-18, -13.7%), p = 0.036. For patients developing TVP, global longitudinal strain was not different from baseline up to the maximum of 3 years -16.6% (-16.7-13.8%) to -16.4% (-17.3, -14.7%) and -17.6% (-18.7, -16.9%) with p = 0.21. Radial strain and torsion showed a trend to decrease after transplantation with time. Circumferential strain remained stable in HTR but decreased in subjects with TVP. Longitudinal Strain and strain rate showed no relevant changes in HTR with and without TVP. Radial strain and torsion declined in HTR as well as TVP patients with time. Speckle tracking imaging is useful to assess organ function in HTR, however coronary angiography is still needed to rule out TVP.

Normothermic ex vivo perfusion provides superior organ preservation and enables viability assessment of hearts from DCD donors

The shortage of donors in cardiac transplantation may be alleviated by the use of allografts from donation after circulatory death (DCD) donors. We have previously shown that hearts exposed to 30 min warm ischemic time and then flushed with Celsior supplemented with agents that activate ischemic postconditioning pathways, show complete recovery on a blood-perfused ex vivo working heart apparatus. In this study, these findings were assessed in a porcine orthotopic heart transplant model. DCD hearts were preserved with either normothermic ex vivo perfusion (NEVP) using a clinically approved device, or with standard cold storage (CS) for 4 h. Orthotopic transplantation into recipient animals was subsequently undertaken. Five of six hearts preserved with NEVP demonstrated favorable lactate profiles during NEVP and all five could be weaned off cardiopulmonary bypass posttransplant, compared with 0 of 3 hearts preserved with CS (p < 0.05, Fisher's exact test). In conclusion, DCD hearts flushed with supplemented Celsior solution and preserved with NEVP display viability before and after transplantation. Viability studies of human DCD hearts using NEVP are warranted.

Late right heart failure during support with continuous-flow left ventricular assist devices adversely affects post-transplant outcome

BACKGROUND

Right heart failure (RHF) is an unresolved issue during continuous-flow left ventricular assist device (LVAD) support. Little is known about post-transplant outcomes in patients complicated by late RHF during LVAD support.

METHODS

Between May 2004 and December 2013, 141 patients underwent cardiac transplantation after isolated LVAD bridging at our center. Late RHF was defined as heart failure requiring medical intervention >4 weeks after LVAD implantation.

RESULTS

The patients' mean age was 53 ± 13 years, 82% were men, and 36% had an ischemic etiology. The mean duration of LVAD support before transplantation was 0.75 years. Late RHF developed in 21 patients (15%) during LVAD support. Of these patients, 11 were supported with inotropic agents at the time of transplantation. Patients with RHF had higher creatinine (1.6 ± 0.88 mg/dL vs 1.3 ± 0.67 mg/dL, p = 0.07), higher blood urea nitrogen (32 ± 17 mg/dL vs 24 ± 10 mg/dL, p = 0.0013), higher total bilirubin (0.96 ± 0.46 mg/dL vs 0.78 ± 0.42 mg/dL, p = 0.07), and lower albumin (3.8 ± 0.60 g/dL vs 4.1 ± 0.46 g/dL, p = 0.0019) at the time of transplantation compared with patients who did not develop RHF. In-hospital mortality was significantly higher in patients with late RHF during LVAD support (29% vs 6.7%, p = 0.002). Overall post-transplant survival rates were 87% at 1 year, 83% at 3 years, and 77% at 5 years. The 5-year post-transplant survival was significantly worse in patients who developed late RHF during LVAD support compared with survival in patients who did not develop RHF (26% vs 87%, p < 0.0001).

CONCLUSIONS

Late RHF during LVAD support adversely affects post-transplant survival.

Hypothermic continuous machine perfusion improves metabolic preservation and functional recovery in heart grafts

The number of heart transplants is decreasing due to organ shortage, yet the donor pool could be enlarged by improving graft preservation. Hypothermic machine perfusion (MP) has been shown to improve kidney, liver, or lung graft preservation. Sixteen pig hearts were recovered following cardioplegia and randomized to two different groups of 4-hour preservation using either static cold storage (CS) or MP (Modified LifePort© System, Organ Recovery Systems, Itasca, Il). The grafts then underwent reperfusion on a Langendorff for 60 min. Energetic metabolism was quantified at baseline, postpreservation, and postreperfusion by measuring lactate and high-energy phosphates. The contractility index (CI) was assessed both in vivo prior to cardioplegia and during reperfusion. Following reperfusion, the hearts preserved using CS exhibited higher lactate levels (56.63 ± 23.57 vs. 11.25 ± 3.92 μmol/g; P < 0.001), increased adenosine monophosphate/adenosine triphosphate (AMP/ATP) ratio (0.4 ± 0.23 vs. 0.04 ± 0.04; P < 0.001), and lower phosphocreatine/creatine (PCr/Cr) ratio (33.5 ± 12.6 vs. 55.3 ± 5.8; P <0.001). Coronary flow was similar in both groups during reperfusion (107 ± 9 vs. 125 + /-9 ml/100 g/min heart; P = ns). CI decreased in the CS group, yet being well-preserved in the MP group. Compared with CS, MP resulted in improved preservation of the energy state and more successful functional recovery of heart graft.

Extracorporeal Membrane Oxygenation for Graft Failure after Heart Transplantation: A Multidisciplinary Approach to Maximize Weaning Rate

Objectives

Primary graft failure (PGF) after heart transplantation is a detrimental complication, and carries high morbidity and mortality. The aim of this study was to analyze the results of our multidisciplinary approach in supporting patients affected with PGF after heart transplantation.

Methods

Out of 114 consecutive patients receiving orthotopic heart transplantation between January 2006 and July 2013, 18 (15.7%) developed PGF requiring veno-arterial extracorporeal membrane oxygenator (VA-ECMO) support. Fourteen patients were male and the mean age was 49 ± 11 years. General principles in treating the patients were based on a low dose of adrenaline (0.05 mic/kg per min) infusion; femoral intra-aortic balloon pump (13 of the 18 patients); low dose of vasoconstrictors; careful fluid balance; daily echocardiographic transesophageal monitoring.

Results

Mean graft recipient pulmonary vascular resistance was 3.6 ± 3.2 WU. Five patients had absolute contraindication to IABP placement. The mean left ventricle ejection fraction pre-VA-ECMO was 18.4% ± 10.2%. The mean VA-ECMO and IABP support times were 6.7 ± 3.2 and 9.2 ± 7.6 days, respectively. Mean VA-ECMO flow was 4164 ± 679 l/min. The mean left ventricle ejection fraction increased to 43.4% ± 17.7% at the end of support. Weaning and discharge rates in patients treated with VA-ECMO+IABP were 84% and 53%, respectively. Causes of death were primarily end-stage organ failure.

Conclusions

A multidisciplinary evaluation of ECMO patients done by intensivists, cardiologists, and surgeons may influence weaning and survival rate. Our approach seems to be a safe and reproducible strategy for avoiding left ventricle distension and fluid overload, and for detecting complications that negatively affect outcomes.

Outcome of cardiac transplantation in patients requiring prolonged continuous-flow left ventricular assist device support

OBJECTIVE

This study assessed the early and late outcomes after cardiac transplantation in patients receiving long-term continuous-flow left ventricular assist device (CF-LVAD) support.

METHODS

Between April 2004 and September 2013, 192 patients underwent HeartMate II (Thoratec, Pleasanton, CA) CF-LVAD placement as a bridge to transplant at our center. Of these, 122 (63%) successfully bridged patients were retrospectively reviewed. Patients were stratified into 2 groups according to their waiting time with CF-LVAD support of <1 year or ≥1 year.

RESULTS

The study cohort was a mean age of 54 ± 13 years, 79% were male, and 35% had an ischemic etiology. The mean duration of CF-LVAD support before transplantation was 296 days (range, 27-1,413 days). The overall 30-day mortality was 4.1%. Overall post-transplant survival was 88%, 84%, 78% at 1, 3, and 5 years, respectively. The 32 patients (26%) with ≥1 year of CF-LVAD support (mean, 635 days) were more likely to have blood type O, a larger body size, and to have been readmitted due to recurrent heart failure and device failure requiring exchange than those with <1 year of CF-LVAD support. Patients who required prolonged support time also had worse in-hospital mortality (16% vs 6.7%, p = 0.12) and significantly lower survival at 3 years after transplantation (68% vs 88%, p = 0.049).

CONCLUSIONS

The overall short-term and long-term cardiac transplant outcomes of patients supported with CF-LVAD are satisfactory. However, patients who require prolonged CF-LVAD support may have diminished post-transplant survival due to adverse events occurring during device support.