Left ventricular dilatation, the presence of intra-cardiac thrombus and short term outcome for primary heart graft failure patients managed with ECMO Alister Sutherland Golden Jubilee National Hospital Glasgow

Primary Graft Failure (cardiac) Primary graft failure is a syndrome which occurs in the immediate postoperative period after cardiac transplantation. reported as the main isolated cause of death within 30 days of implantation (Lyer, et al. 2011) aetiology is dependent upon inherent factors present in the donor, recipient and pre/peri-operative care. The donor heart is subjected to a series of insults during the transplant process including hypothermic storage, warm ischemia, reperfusion and the brain death of the donor with resultant catecholamine release. “acute re-perfusion injury and myocardial stun are likely the predominant factors in PGF development” (Lyer et al, 2011) The prevalence of PGF across performing centres can range from 2-28%. A disparity which is driven in part by the lack of unilateral diagnostic criteria. (Ibrahim, Moheb, et al. 2007)

Diagnosing Primary Graft Failure

ECMO as a treatment for Primary Graft Failure (PGF) “Early institution of MCS improves outcomes in PGF” (Marasco, et al. 2005). 1 yr Survival rates of 40% compared to 80% in non-PGF post transplant patients and rates approaching 0% in PGF patients not treated with MCS. (D`Allessandro, et al. 2010) Complications Problems are legion and varied. Most frequently comprise renal failure, sepsis, and bleeding. (Zangrillo, et al. 2013) Two common complications of ECMO therapy in the PGF population are; Intra-cardiac thrombus. Left Ventricular dilation.

Question   Are intra-cardiac thrombus (LVt) and left ventricular dilation (LVd) associated with poorer short term outcomes for Primary Graft Failure (PGF) patients treated with Veno- arterial ECMO? Do variations in ECMO delivery affect the occurrence of either LVd / LVt? LVd = left ventricular dilation / distension / overloading described and notated during echocardiographic investigation. LVt = thrombotic collections present in the left sided heart chambers as described during echocardiographic investigation during ECMO therapy

Retrospective review of 17 Primary Graft Failure patients who were treated with ECMO at the Golden Jubilee National Hospital (Clydebank, Glasgow). Mean (+/- StDev) Therapylength (Hrs) 111.71 (+/- 58.79) Age 44.65 (+/- 11.67) B.S.A 1.93 (+/- 0.15) Male (%) 82.35 IABP on ECMO (%) 100.00 Central Cannulation (%) Medos hilite 7000lt oxygenator (%) Exclusions; 2 cases of ECMO therapy <12hrs 1 case of “stone heart” 1 case of heparin-induced thrombocytopenia (HIT)

“ECMO service is data rich but analytically poor” 48hrs of raw data from typical ECMO run (not shown are comments and investigation reports)

Short term Outcomes The short term outcomes for this cohort group (n17) were that; 7 patients recovered enough primary graft function to allow weaning from ECMO 5 were converted to a Ventricular Assist Device (VAD) 5 were unable to be weaned from ECMO and care was withdrawn.

Age, B.S.A and therapy length were not associated with short term outcome.

Left ventricular dilation +ve/-ve groups When divided into groups based on presence of LV dilation, outcomes were worse when dilation was present.

Left ventricular dilation +ve/-ve groups Age, B.S.A and therapy length were not associated with left ventricular dilation in this cohort.

Left ventricular dilation +ve/-ve groups When divided into groups based on presence of LV dilation, there was no difference in the volume or number of transfused blood products.

Left ventricular dilation +ve/-ve groups The ACT IQR for patients with dilation doesn’t cover target levels. LVd +ve The measured ACT’s of patients was not associated with left ventricular dilation in this cohort

Left ventricular dilation +ve/-ve groups The % Flow IQR for patients with dilation extends above100% of calculated, while non-dilation patients IQR extends below 100% At 95% CI, the % of calculated flow delivered is statistically related to left ventricular dilation in this cohort

Left sided Intra-cardiac Thrombus +/-ve groups When divided into groups based on presence of Lt, outcomes were worse when thrombus was present.

Left sided Intra-cardiac Thrombus +/-ve groups Age, B.S.A and therapy length were not associated with left sided intra-cardiac thrombus.

Left sided Intra-cardiac Thrombus +/-ve groups When divided into groups based on presence of LVt, there was no difference in the volume or number of transfused blood products.

Left sided Intra-cardiac Thrombus +/-ve groups The ACT IQR box for patients with thrombus only slightly covers target therapeutic levels. The measured ACT’s of patients was not associated with left sided intracardiac thrombus.

Left sided Intra-cardiac Thrombus +/-ve groups The % Flow IQR for patients with Thrombus extends above100% of calculated, while non-thrombus patients IQR extends below 100% At 95% CI, the % of calculated flow delivered is statistically related to Intra-cardiac thrombus in this cohort

Conclusions from this study Both left ventricular dilation and intra-cardiac thrombus were associated with worse outcomes in the studied cohort. The % of calculated flow delivered was the only variable of ECMO delivery we examined which was statistically related to the occurrence of dilation / thrombus. Specifically, delivery of high % calculated flows seemed associated with both dilation and thrombus.

Should these findings alter our practice? A trend toward delivering lower % flows is already developing and compliments the findings of the study.

Thank You. Questions?

Why Not Both? 5 patients were identified as having both LVt and LVd. Worse short term outcomes than either LVt / LVd in isolation, however the sample size remains small and this study does not claim statistical significance. Thrombus occurred in isolation more often than dilation i.e-50% of thrombus patients had dilation while 70% of dilation patients had thrombus.