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Analysis and Review of Clinical and Scientific Findings of Preservation Solutions to Minimize Donor Organ Damage March 26 and April 1, 2009 1 Histidine-Tryptophan-Ketoglutarate Solution Vs. University of Wisconsin Solution for Deceased Donor Liver Transplantation: Analysis of SRTR Database John Fung, MD, PhD Chairman of the Department of General Surgery Cleveland Clinic Purpose • This analysis aims to evaluate the impact of the organ preservation solutions (OPS) ,(Histidine-TryptophanKetoglutarate (HTK) vs. University of Wisconsin (UW) solution) on the outcome of adult deceased donor liver transplantation (DDLT) using the Scientific Registry of Transplant Recipient (SRTR) database. Materials and Methods Only adult first liver-only transplants from 2002-2006. We included only those for whom both flush and storage solutions were the same. Risk-unadjusted graft survival was estimated non-parametrically by the method of Kaplan and Meier, and parametrically by a multiphase hazard decomposition method Statistical Analysis • Risk factors for graft survival were determined using nonproportional, multiphase, multivariable hazard methodology. This methodology allows modeling of recipient, donor, and procedure variables in all phases of the hazard model simultaneously. Bootstrap aggregating was used for variable selection with a probability for inclusion of .001; variables appearing in at least 50% of bootstrap analyses were considered reliably statistically significant at p<.001. Patients • The data set included 20,908 patients, 17,559 (84%) with UW and 3349 (16%) with HTK solutions. Mean follow-up was 2.9 ± 1.5 years (3.0 ± 1.5 years for UW and 1.9 ± 1.0 years for HTK). We defined an early phase (EP) shortly after DDLT followed by a constant phase (CP) of hazard for graft failure. Results • Significant predictors of graft failure in the EP after DDLT include the following recipient factors: older age, race either White or Black, portal vein thrombosis, last creatinine and last MELD for the transplant (tx) candidacy, on life support just prior to tx, and previous kidney tx. Risk Factors for Graft Failure Early Phase Risk Factor P Bootstrap % Early hazard phase Older recipient age (years) <.0001 93 .0005 69 Recipient portal vein thrombosis <.0001 95 Recipient previous abdominal surgery <.0001 48 Candidate last creatinine (used for MELD) <.0001 86 Candidate last MELD <.0001 71 Recipient on life support just prior to tx <.0001 100 Recipient previous kidney transplant <.0001 90 Donor race non-White <.0001 67 Donor donation after cardiac death <.0001 100 Donor risk index <.0001 46 Recipient race White or Black Risk Factors for Graft Failure Constant Phase Risk Factor P Bootstrap % Constant hazard phase African American recipient <.0001 97 Recipient tumor (incidental) at transplant <.0001 88 Recipient primary diagnosis for tumors <.0001 87 Recipient hepatitis C virus <.0001 100 Donor age (years) <.0001 97 Donor history of diabetes <.0001 77 Results • Significant donor factors in the EP are: race other than White, donation after cardiac death (DCD) and donor risk index (DRI). OPS did not appear as a statistically significant predictor of graft failure. Results • OPS was not statistically significant (p=.06, EP; p=.2, CP). Hospital death, re-transplant rates (overall and within 14 days of initial transplant) and relisting rates (overall and within 30 days of tx) were similar (p>0.05). Patient Survival - Donor >65 • • • • Donor Age > 65 N=1698 UW N= 311 HTK p=.46 log rank test Patient Survival - Donor <65 • • • • Donor Age <65 N=15861 UW N= 3038 HTK p=.28 log rank test Patient Survival - DCD Donor • • • • DCD Donor N=570 UW N=159 HTK p=.73 log rank test Patient Survival - Non-DCD Donor • Non-DCD Donor • N=16989 UW • N=3190 HTK • p=.55 log rank test Patient Survival - DRI >2.5 • • • • Donor DRI >2.5 N=8663 UW N=1682 HTK p=.25 log rank test Patient Survival - DRI <2.5 • • • • Donor DRI <2.5 N=6600 UW N=1218 HTK p=.37 log rank test Graft Survival - Donor Age >65 • • • • Donor Age >65 N=1698 UW N= 311 HTK p=.64 log rank test Graft Survival - Donor Age <65 • • • • Donor Age <65 N=15861 UW N= 3038 HTK p=.045 log rank test Graft Survival - DCD Donor • • • • DCD Donor N=570 UW N=159 HTK p=.17 log rank test Kaplan-Meier Adult Graft Survival Primary Deceased Donor Liver Transplants 2000-2006 Survival Rate (%) . 100 90 80 70 60 50 40 30 20 10 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 Months Post Transplant DBD DCD-UW DCD-HTK SRTR Includes adult, primary, liver alone transplants Graft Survival - Non-DCD Donor • Non-DCD Donor • N=16989 UW • N=3190 HTK • p=.23 log rank test Graft Survival - DRI >2.5 • • • • Donor DRI >2.5 N=8663 UW N=1682 HTK p=.053 log rank test Graft Survival - DRI <2.5 • • • • Donor DRI <2.5 N=6600 UW N=1218 HTK p=.15 log rank test Analyzing Studies • In addition to the common underlying OPTN data, SSAF files include extra ascertainment of outcomes from SSDMF, and from crosslinking of records within the OPTN data for the same person. Files are linked by a patient key so that the entire history of a particular person can be studied. The extent to which these links are made, and the specific matching process, may be different between the two sets of files. SRTR Information Flow Monthly Transfer OPTN Person Linking SRTR CMSESRD SSDMF SEER Data Quality Analysis File Creation Data Fixes Feedback OPTN MPSC OPOSpecific Reports Data Use Agreements Standard Analysis Files Center-Specific Analyses CenterSpecific Reports NCHS, AHA, etc Reorganization for Research Cleaning and Validation Analysis Variables Added Public Release External Research Analytical Procedures and Products TAC RFI Journal Articles Conference Present’ns OPTN, ACOT Committees Annual, Biennial Reports Hopkins UNOS Analysis Used casewise deletion of missing data, i.e. threw out cases that were missing any of the predictor variables they were studying. Doing this can potentially bias the results. It means they are using only patients for whom all variables were reported - and these patients might come from centers where they are more diligent about data reporting, etc. Implications of Casewise Deletions • While they do say that data were missing for less than 4% of covariates, if the missing values were scattered over 20% of patients, then 20% of total data might have been deleted. • Example: – SRTR CIT data: 100% complete – UNOS CIT data: 86% complete Critique • Last transplant included was 2/28/08 - the paper was submitted on 7/17/08. Assuming that it took 45 days to analyze and write the paper, then it would be safe to say that the data cutoff was 6/1/08, meaning that the last patients only had a 3 month followup. However, the first recipient follow-up form required by UNOS is at 6 months and then they only release data after a 60 day period for completion, meaning that for a 6/1/08 cutoff, they only have data for transplants performed before 11/1/07. % Unvalidate… Validation of Follow-Up Forms by Year 100% 50% Pr eU… 0% 0 … Months 6 after 12Form18 is Source: SRTR analyses, August 2003 for the 2003 OPTN/SRTR Annual Report, Figure II-4. Other Considerations • Slightly different timeframes: – is there a change in clinical practice? – is there a learning curve for new users of HTK? • Do the conclusions make sense? – Recipient age 18-34 HR 1.14 – COD - CVA, HR 1.04 (SRTR HR 1.16) – COD - DCD, HR 1.97 (SRTR HR 1.51) Does Not Fit Clinical Impressions • Cleveland Clinic DCD experience – 15 controlled DCD LTX preserved with HTK since 2005 – Heparin could not be given prior to declaration of death – Mean donor age was 38 ± 12 years – Mean WIT and CIT was 25 ± 9 min and 427 ± 97 min, respectively – No recipient developed ITBS. PNF was seen in one recipient who was salvaged with retransplantation Analysis and Review of Clinical and Scientific Findings of Preservation Solutions to Minimize Donor Organ Damage Richard S. Mangus, MD, MS Assistant Professor of Surgery and Transplant Surgeon Transplant Division, Department of Surgery Indiana University, School of Medicine March 26 and April 1, 2009 35 Disclosure Dr. Mangus has participated in the advisory board and speaker’s bureau for Essential Pharmaceuticals in the last 12 months. 36 Assessment of Scientific Research • Systematic assessment of data quality • Study types: Expert opinion Non-experimental studies (questionnaire) Observational studies (retrospective analysis) Non-randomized parallel cohort studies (prospective) Randomized, blinded, prospective trial (RCTs) Systematic review and meta-analysis of randomized trials • Issues: CONFOUNDING Relevance Accuracy Timeliness Bias Timeliness Comparability Reproducibility Incomplete data 37 Randomized, controlled trials (RCTs) • Kidney 1 European, 3-year follow-up 1998, n = 650 transplants, Deceased donors • Pancreas 1 European 2009, n=68 transplants • Liver 3 European 1994 (n=60) – Deceased donors 2003 (n=30) – Living donors 2005 (n=40) – Deceased donors 38 Kidney preservation Transplants: HTK 332, UW 312 DGF: Need for dialysis 2 or more times during first 7-days post-transplant Flush volume: HTK 5 – 6 L UW 1 – 2 L EC 4L 39 Kidney preservation de Boer, et al, Transpl Proc, 1999; 31: 2065 40 Kidney preservation de Boer, et al, Transpl Proc, 1999; 31: 2065 41 Kidney preservation Lynch RJ, et al. AJT 2008; 8:567-73 42 Kidney preservation Post-transplant kidney graft survival Living Donor: HTK n=475 UW n=475 Deceased donor: HTK n=317 UW n=317 Lynch RJ, et al. AJT 2008; 8:567-73 43 Pancreas preservation Transplants: 68 transplants over 18 months at 4 centers Outcomes: 6-month graft survival – NO DIFFERENCE Graft function – NO DIFFERENCE Fasting BG C-peptide level HbA1c Insulin requirement Flush volume: HTK UW 5–8L 3L n=41 n=67 44 Pancreas preservation Figure 1. No insulin requirement Figure 2. Serum amylase level Figure 3. Serum lipase level 45 Pancreas preservation Figure 4. C-peptide level Figure 5. Units exogenous insulin Figure 6. HbA1c 46 Pancreas preservation Indiana University, 2003 to 2007 N = 310 HTK 262, UW 48 Simultaneous, retrospective 1-year graft survival – 91% (U.S. 79-86%) 47 Pancreas preservation • ISSUES: Graft pancreatitis Alonso D, et al. Increased pancreatitis in allografts flushed with histidine-tryptophan-ketoglutarate solution: a cautionary tale. AJT 2008; 8: 1942-45. • Overall rate of graft pancreatitis 28/97 (29%) • Two centers, retrospective, low volume (HTK 16, UW 81) Flush volume • 10 L likely too much and may cause pancreas graft injury from edema (related to low viscosity and high volume flush) • Indiana University – 3000-4000cc routinely no graft pancreatitis graft thombosis rate 3-4% 48 Liver preservation 3 Randomized Studies: 1. Erhard J, et al. Comparison of HTK versus UW for organ preservation in human liver transplantation: A prospective, randomized study. Transplant International 1994; 7: 177-81. • 60 deceased donor liver transplants (HTK n=30 and UW n=30) • No difference in early and late graft survival, even for 7 donor livers with cold ischemia time >15 hrs • More late biliary complications in UW group. • Higher initial transaminases in HTK group. 2. Testa G, et al. HTK versus UW in living donor liver transplantation: results of a prospective study. Liver Transplantation 2003; 9(8): 822-26. • 30 consecutive living donor right lobe transplants flushed alternately with HTK (n=16) or UW (n=14) • Patients were randomly allocated based upon timing of transplantation • 1-year post-transplant, there is no difference in graft and patient survival, liver enzymes and complications 3. Nardo B, et al. Preliminary results of a clinical randomized study comparing Celsior and HTK solutions in liver preservation for transplantation. Transpl Proc 2005; 37:320-2. • European randomized trial comparing Celsior and HTK. • No difference in initial function or survival up to 1-year post-transplant. 49 Liver preservation 50 Liver preservation Indiana University, 2001 to 2008 All adult, deceased donor n=1013 HTK 632, UW 381 Simultaneous, retrospective 51 Liver preservation Indiana University, 2001 to 2008 Post-liver transplant serum ALT, n=1013 600 All adult, deceased donor Simultaneous, retrospective 500 HTK 632 UW 381 HTK 300 UW Serum ALT 200 100 0 0 5 10 15 20 25 30 35 Days post-transplant Post-liver transplant serum total bilirubin, n=1013 4 3.5 Serum total bilirubin n=1013 Serum ALT 400 3 2.5 HTK 2 UW 1.5 Serum Bilirubin 1 0.5 0 0 5 10 15 20 25 30 35 Days post-transplant 52 Recent retrospective database reviews 53 Recent retrospective database reviews • Data review: – Usually large database is better to increase numbers – In large transplant research, single center better to maintain homogeneous patient, donor and management factors • Database review – Only as strong as weakest data – Selection bias -> • Do surgeons who use HTK differ from those that use UW ? • Multiple comparisons dilute findings • CONFOUNDING – database differences likely just highlight differences in practice patterns between surgeons who use HTK and those who use UW – Kidney study – exclude all machine pumped kidneys – Pancreas study – unable to differentiate high risk grafts – Liver study – no ability to analyze steatosis, hypernatremia, etc 54 Summary • All randomized controlled trials across multiple organs, countries and time periods demonstrate no difference in clinical outcomes between HTK and UW • Large single center case series across multiple organs, countries and time periods consistently demonstrate no difference in clinical outcomes between HTK and UW • Question of appropriate flush volume - of particular importance to the pancreas • Recent database reviews of tens of thousands of patients likely reflect difference in practice patterns between surgeons who use HTK and those who use UW. Unlikely to represent a true difference in the clinical outcomes of the two solutions when higher quality studies show no difference. 55