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Robert M Merion

Publications and source records attributed to Robert M Merion.

At least 19 recordsLinked to original sources
PubMed2006

Educational web-based intervention for high school students to increase knowledge and promote positive attitudes toward organ donation.

A sample of 490 high school students from 81 schools in Michigan participated in an experiment in which they were randomly assigned to either a control or an experimental Web site. The experimental Web site provided exposure to educational material about the process of organ donation and organ transplantation. The control Web site provided educational material on methods to avoid the common cold. The pre-and posttests of knowledge of issues related to organ donation and of attitude toward donation demonstrated statistically significant increases for the experimental group compared with the control group. A structural equation path model suggested that these increases in knowledge and prodonation attitude mediated the effects of the experiment on contacting the Michigan donor registry. The increase in knowledge and in prodonation attitude increased the likelihood of contacting the registry. The potential for this and similar other Web interventions to enhance students' health education is discussed.

Adolescent↗
PubMed2006

Donation after cardiac death as a strategy to increase deceased donor liver availability.

OBJECTIVE: This study examines donation after cardiac death (DCD) practices and outcomes in liver transplantation. SUMMARY BACKGROUND DATA: Livers procured from DCD donors have recently been used to increase the number of deceased donors and bridge the gap between limited organ supply and the pool of waiting list candidates. Comprehensive evaluation of this practice and its outcomes has not been previously reported. METHODS: A national cohort of all DCD and donation after brain-death (DBD) liver transplants between January 1, 2000 and December 31, 2004 was identified in the Scientific Registry of Transplant Recipients. Time to graft failure (including death) was modeled by Cox regression, adjusted for relevant donor and recipient characteristics. RESULTS: DCD livers were used for 472 (2%) of 24,070 transplants. Annual DCD liver activity increased from 39 in 2000 to 176 in 2004. The adjusted relative risk of DCD graft failure was 85% higher than for DBD grafts (relative risk, 1.85; 95% confidence interval, 1.51-2.26; P < 0.001), corresponding to 3-month, 1-year, and 3-year graft survival rates of 83.0%, 70.1%, and 60.5%, respectively (vs. 89.2%, 83.0%, and 75.0% for DBD recipients). There was no significant association between transplant program DCD liver transplant volume and graft outcome. CONCLUSIONS: The annual number of DCD livers used for transplant has increased rapidly. However, DCD livers are associated with a significantly increased risk of graft failure unrelated to modifiable donor or recipient factors. Appropriate recipients for DCD livers have not been fully characterized and recipient informed consent should be obtained before use of these organs.

Adolescent↗
PubMed2005

Deceased-donor characteristics and the survival benefit of kidney transplantation.

CONTEXT: Transplantation using kidneys from deceased donors who meet the expanded criteria donor (ECD) definition (age > or =60 years or 50 to 59 years with at least 2 of the following: history of hypertension, serum creatinine level >1.5 mg/dL [132.6 micromol/L], and cerebrovascular cause of death) is associated with 70% higher risk of graft failure compared with non-ECD transplants. However, if ECD transplants offer improved overall patient survival, inferior graft outcome may represent an acceptable trade-off. OBJECTIVE: To compare mortality after ECD kidney transplantation vs that in a combined standard-therapy group of non-ECD recipients and those still receiving dialysis. DESIGN, SETTING, AND PATIENTS: Retrospective cohort study using data from a US national registry of mortality and graft outcomes among kidney transplant candidates and recipients. The cohort included 109,127 patients receiving dialysis and added to the kidney waiting list between January 1, 1995, and December 31, 2002, and followed up through July 31, 2004. MAIN OUTCOME MEASURE: Long-term (3-year) relative risk of mortality for ECD kidney recipients vs those receiving standard therapy, estimated using time-dependent Cox regression models. RESULTS: By end of follow-up, 7790 ECD kidney transplants were performed. Because of excess ECD recipient mortality in the perioperative period, cumulative survival did not equal that of standard-therapy patients until 3.5 years posttransplantation. Long-term relative mortality risk was 17% lower for ECD recipients (relative risk, 0.83; 95% confidence interval, 0.77-0.90; P<.001). Subgroups with significant ECD survival benefit included patients older than 40 years, both sexes, non-Hispanics, all races, unsensitized patients, and those with diabetes or hypertension. In organ procurement organizations (OPOs) with long median waiting times (>1350 days), ECD recipients had a 27% lower risk of death (relative risk, 0.73; 95% confidence interval, 0.64-0.83; P<.001). In areas with shorter waiting times, only recipients with diabetes demonstrated an ECD survival benefit. CONCLUSIONS: ECD kidney transplants should be offered principally to candidates older than 40 years in OPOs with long waiting times. In OPOs with shorter waiting times, in which non-ECD kidney transplant availability is higher, candidates should be counseled that ECD survival benefit is observed only for patients with diabetes.

Adolescent↗
PubMed2005

Impact of the expanded criteria donor allocation system on the use of expanded criteria donor kidneys.

BACKGROUND: The U.S. Organ Procurement and Transplantation Network recently implemented a policy allocating expanded criteria donor (ECD) kidneys by waiting time alone. ECD kidneys were defined as having a risk of graft failure > or = 1.7 times that of ideal donors. ECDs include any donor > or = 60 years old and donors 50 to 59 years old with at least two of the following: terminal creatinine >1.5 mg/dL, history of hypertension, or death by cerebrovascular accident. The impact of this policy on use of ECD kidneys is assessed. METHODS: The authors compared use of ECD kidneys recovered in the 18 months immediately before and after policy implementation. Differences were tested using t test and chi2 analyses. RESULTS: There was an 18.3% increase in ECD kidney recoveries and a 15.0% increase in ECD kidney transplants in the first 18 months after policy implementation. ECD kidneys made up 22.1% of all recovered kidneys and 16.8% of all transplants, compared with 18.8% (P<0.001) and 14.5% (P<0.001), respectively, in the prior period. The discard rate was unchanged. The median relative risk (RR) for graft failure for transplanted ECD kidneys was 2.07 versus 1.99 in the prepolicy period (P=not significant); the median RR for procured ECD kidneys was unchanged at 2.16. The percentage of transplanted ECD kidneys with cold ischemia times (CIT) <12 hr increased significantly; the corresponding percentage for CIT > or = 24 hr decreased significantly. CONCLUSIONS: The recent increase in ECD kidney recoveries and transplants appears to be related to implementation of the ECD allocation system.

Humans↗
PubMed2005

Hepatitis C is a risk factor for death after liver retransplantation.

Retransplantation for liver allograft failure associated with hepatitis C virus (HCV) has been increasing due to nearly universal posttransplant HCV recurrence and has been demonstrated to be associated with poor outcomes. We report on the risk factors for death after retransplantation among liver recipients with HCV. A retrospective cohort of liver transplant recipients who underwent retransplantation between January 1997 and December 2002 was identified in the Scientific Registry of Transplant Recipients database. Cox regression was used to assess the relative effect of HCV diagnosis on mortality risk after retransplantation and was adjusted for multiple covariates. Of 1,718 liver retransplantations during the study period, 464 (27%) were associated with a diagnosis of HCV infection. Based on Cox regression, retransplant recipients with HCV had a 30% higher covariate-adjusted mortality risk than those without HCV diagnosis (hazard ratio [HR], 1.30; 95% confidence interval [CI], 1.10-1.54; P = 0.002). Other covariates associated with significant relative risk of death after retransplantation included older recipient age, presence in an intensive care unit (ICU), serum creatinine, and donor age. Additional regression analysis revealed that the increase in mortality risk associated with HCV was concentrated between 3 and 24 months postretransplantation, among patients age 18 to 39 at retransplant, and in patients retransplanted during the years 2000 to 2002. In conclusion, HCV liver recipients account for a considerable proportion of all retransplantations performed. Surprisingly, younger age predicted a higher mortality for recipients with HCV undergoing liver retransplantation. This may reflect a willingness to retransplant younger patients with an increased severity of illness or a more virulent HCV infection in this population. Although HCV was predictive of an increased risk of death, consideration of other characteristics of HCV patients, including donor and recipient age and need for preoperative ICU care may identify those at significantly higher risk.

Adolescent↗
PubMed2005

Outcomes of 385 adult-to-adult living donor liver transplant recipients: a report from the A2ALL Consortium.

OBJECTIVE: The objective of this study was to characterize the patient population with respect to patient selection, assess surgical morbidity and graft failures, and analyze the contribution of perioperative clinical factors to recipient outcome in adult living donor liver transplantation (ALDLT). SUMMARY BACKGROUND DATA: Previous reports have been center-specific or from large databases lacking detailed variables. The Adult-to-Adult Living Donor Liver Transplantation Cohort Study (A2ALL) represents the first detailed North American multicenter report of recipient risk and outcome aiming to characterize variables predictive of graft failure. METHODS: Three hundred eighty-five ALDLT recipients transplanted at 9 centers were studied with analysis of over 35 donor, recipient, intraoperative, and postoperative variables. Cox regression models were used to examine the relationship of variables to the risk of graft failure. RESULTS: Ninety-day and 1-year graft survival were 87% and 81%, respectively. Fifty-one (13.2%) grafts failed in the first 90 days. The most common causes of graft failure were vascular thrombosis, primary nonfunction, and sepsis. Biliary complications were common (30% early, 11% late). Older recipient age and length of cold ischemia were significant predictors of graft failure. Center experience greater than 20 ALDLT was associated with a significantly lower risk of graft failure. Recipient Model for End-stage Liver Disease score and graft size were not significant predictors. CONCLUSIONS: This multicenter A2ALL experience provides evidence that ALDLT is a viable option for liver replacement. Older recipient age and prolonged cold ischemia time increase the risk of graft failure. Outcomes improve with increasing center experience.

Adult↗
PubMed2005

Extracorporeal support for organ donation after cardiac death effectively expands the donor pool.

BACKGROUND: We sought to evaluate the effect on short-term outcomes of normothermic, extracorporeal perfusion (ECMO) for donation of abdominal organs for transplantation after cardiac death (DCD). Study parameters included increase in number of donors and organs, types of organs procured, and viability of kidneys transplanted. METHODS: We retrospectively reviewed medical record data for all patients enrolled in our ECMO-supported DCD donor protocol between 10/1/2000 to 2/01/2004. We also reviewed the records for all patients undergoing organ donation after brain-death (DBD) during the study period at our institution. Recipient data were obtained and analyzed for all kidneys procured from both groups. RESULTS: Twenty patients were enrolled in our DCD protocol and underwent attempted organ donation. Fifteen patients completed the protocol; 3 maintained cardiac function throughout the prescribed 60 minutes after withdrawal of life support, and two patients' organs were deemed unsuitable for transplantation. Fourteen (70%) of the DCD donor patients originated on the trauma service and six (30%) were from other clinical services. The DCD program increased the potential donor pool by 33% (61 versus 81 patients) and the number of kidneys transplanted by 24% (100 versus 124). A total of 24 kidney, 5 liver, and 1 pancreas transplants were performed with these organs. Two of 24 (8.3%) DCD kidneys had delayed graft function. There were no perioperative rejection episodes or deaths. CONCLUSION: The implementation of a DCD protocol using extracorporeal perfusion increased the potential organ donor pool at our institution by 33%. This was accomplished without short term adverse effect on organ function compared with kidneys transplanted from DBD donors.

Adolescent↗
PubMed2005

Kidney transplantation and wait-listing rates from the international Dialysis Outcomes and Practice Patterns Study (DOPPS).

BACKGROUND: The international Dialysis Outcomes and Practice Patterns Study (DOPPS I and II) allows description of variations in kidney transplantation and wait-listing from nationally representative samples of 18- to 65-year-old hemodialysis patients. The present study examines the health status and socioeconomic characteristics of United States patients, the role of for-profit versus not-for-profit status of dialysis facilities, and the likelihood of transplant wait-listing and transplantation rates. METHODS: Analyses of transplantation rates were based on 5267 randomly selected DOPPS I patients in dialysis units in the United States, Europe, and Japan who received chronic hemodialysis therapy for at least 90 days in 2000. Left-truncated Cox regression was used to assess time to kidney transplantation. Logistic regression determined the odds of being transplant wait-listed for a cross-section of 1323 hemodialysis patients in the United States in 2000. Furthermore, kidney transplant wait-listing was determined in 12 countries from cross-sectional samples of DOPPS II hemodialysis patients in 2002 to 2003 (N= 4274). RESULTS: Transplantation rates varied widely, from very low in Japan to 25-fold higher in the United States and 75-fold higher in Spain (both P values <0.0001). Factors associated with higher rates of transplantation included younger age, nonblack race, less comorbidity, fewer years on dialysis, higher income, and higher education levels. The likelihood of being wait-listed showed wide variation internationally and by United States region but not by for-profit dialysis unit status within the United States. CONCLUSION: DOPPS I and II confirmed large variations in kidney transplantation rates by country, even after adjusting for differences in case mix. Facility size and, in the United States, profit status, were not associated with varying transplantation rates. International results consistently showed higher transplantation rates for younger, healthier, better-educated, and higher income patients.

Adolescent↗
PubMed2005

Thoracic organ transplantation in the United States, 1994-2003.

Using OPTN/SRTR data, this article reviews the state of thoracic organ transplantation in 2003 and the previous decade. Time spent on the heart waiting list has increased significantly over the last decade. The percentage of patients awaiting heart transplantation for >2 years increased from 23% in 1994 to 49% by 2003. However, there has been a general decline in heart waiting list death rates over the decade. In 2003, the lung transplant waiting list reached a record high of 3,836 registrants, up slightly from 2002 and more than threefold since 1994. One-year patient survival for those receiving lungs in 2002 was 82%, a statistically significant improvement from 2001 (78%). The number of patients awaiting a heart-lung transplant, declining since 1998, reached 189 in 2003. Adjusted patient survival for heart-lung recipients is consistently worse than the corresponding rate for isolated lung recipients, primarily due to worse outcomes for heart-lung recipients with congenital heart disease. A new lung allocation system, approved in June 2004, derives from the survival benefit of transplantation with consideration of urgency based on waiting list survival, instead of being based solely on waiting time. A goal of the policy is to minimize deaths on the waiting list.

Female↗
PubMed2005

The survival benefit of liver transplantation.

Demand for liver transplantation continues to exceed donor organ supply. Comparing recipient survival to that of comparable candidates without a transplant can improve understanding of transplant survival benefit. Waiting list and post-transplant mortality was studied among a cohort of 12 996 adult patients placed on the waiting list between 2001 and 2003. Time-dependent Cox regression models were fitted to determine relative mortality rates for candidates and recipients. Overall, deceased donor transplant recipients had a 79% lower mortality risk than candidates (HR = 0.21; p < 0.001). At Model for End-stage Liver Disease (MELD) 18-20, mortality risk was 38% lower (p < 0.01) among recipients compared to candidates. Survival benefit increased with increasing MELD score; at the maximum score of 40, recipient mortality risk was 96% lower than that for candidates (p < 0.001). In contrast, at lower MELD scores, recipient mortality risk during the first post-transplant year was much higher than for candidates (HR = 3.64 at MELD 6-11, HR = 2.35 at MELD 12-14; both p < 0.001). Liver transplant survival benefit at 1 year is concentrated among patients at higher risk of pre-transplant death. Futile transplants among severely ill patients are not identified under current practice. With 1 year post-transplant follow-up, patients at lower risk of pre-transplant death do not have a demonstrable survival benefit from liver transplant.

Adolescent↗
PubMed2004

Summary report of a national conference: Evolving concepts in liver allocation in the MELD and PELD era. December 8, 2003, Washington, DC, USA.

A national conference was held to review and assess data gathered since implementation of MELD and PELD and determine future directions. The objectives of the conference were to review the current system of liver allocation with a critical analysis of its strengths and weaknesses. Conference participants used an evidence-based approach to consider whether predicted outcome after transplantation should influence allocation, to discuss the concept of minimal listing score, to revisit current and potential expansion of exception criteria, and to determine whether specific scores should be used for automatic removal of patients on the waiting list. After review of data from the first 18 months since implementation, association and society leaders, and surgeons and hepatologists with wide regional representation were invited to participate in small group discussions focusing on each of the main objectives. At the completion of the meeting, there was agreement that MELD has had a successful initial implementation, meeting the goal of providing a system of allocation that emphasizes the urgency of the candidate while diminishing the reliance on waiting time, and that it has proven to be a powerful tool for auditing the liver allocation system. It was also agreed that the data regarding the accuracy of PELD as a predictor of pretransplant mortality were less conclusive and that PELD should be considered in isolation. Recommendations for the transplant community, based on the analysis of the MELD data, were discussed and are presented in the summary document.

Adult↗
PubMed2004

When is a patient too well and when is a patient too sick for a liver transplant?

1. Liver transplantation is currently offered as a therapeutic option for patients with a wide range of end-stage liver diseases. 2. Conventional wisdom suggests that patients who receive a liver transplant have a greater expected lifetime when compared to comparable candidates on the waiting list. 3. The model for end-stage liver disease (MELD) scoring system is an excellent predictor of mortality on the waiting list and also predicts mortality after liver transplantation. 4. The combination of waiting list mortality risk and posttransplant mortality risk assessed by MELD and other factors can be used to estimate whether candidates are likely to derive a survival benefit from a liver transplant.

Decision Support Techniques↗
PubMed2004

Selection of pediatric candidates under the PELD system.

1. The PELD score accurately predicts the 3 month probability of waiting list death for children with chronic liver disease. 2. Comparing pre and post PELD and MELD implementation, the percent of children receiving deceased donor livers increased and the percent of children dying on the list decreased after PELD/MELD implementation. 3. Excluding children transplanted at status 1, the largest percentage of children are transplanted at a PELD score < 10. 4. Before MELD/PELD 48% of all children receiving deceased donor organs were transplanted at status 1, compared to 41% in the PELD/MELD era. Wide regional variation occurs.

Adult↗
PubMed2004

Simulating the allocation of organs for transplantation.

The demand for donated organs greatly exceeds supply and many candidates die awaiting transplantation. Policies for allocating deceased donor organs may address equity of access and medical efficacy, but typically must be implemented with incomplete information. Simulation-based analysis can inform the policy process by predicting the likely effects of alternative policies on a wide variety of outcomes of interest. This paper describes a family of simulations developed by the US Scientific Registry of Transplant Recipients and initial experience in the application of one member of this family, the Liver Simulated Allocation Model (LSAM).

Humans↗