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Featured researches published by Ty B. Dunn.


Journal of The American College of Surgeons | 2012

Total Pancreatectomy and Islet Autotransplantation for Chronic Pancreatitis

David E. R. Sutherland; David M. Radosevich; Melena D. Bellin; B. J. Hering; Gregory J. Beilman; Ty B. Dunn; Srinath Chinnakotla; Selwyn M. Vickers; Barbara Bland; A. N. Balamurugan; Martin L. Freeman; Timothy L. Pruett

BACKGROUND Total pancreatectomy (TP) with intraportal islet autotransplantation (IAT) can relieve pain and preserve β-cell mass in patients with chronic pancreatitis (CP) when other therapies fail. We report on a >30-year single-center series. STUDY DESIGN Four hundred and nine patients (including 53 children, 5 to 18 years) with CP underwent TP-IAT from February 1977 to September 2011 (etiology: idiopathic, 41%; Sphincter of Oddi dysfunction/biliary, 9%; genetic, 14%; divisum, 17%; alcohol, 7%; and other, 12%; mean age was 35.3 years, 74% were female; 21% has earlier operations, including 9% Puestow procedure, 6% Whipple, 7% distal pancreatectomy, and 2% other). Islet function was classified as insulin independent for those on no insulin; partial, if known C-peptide positive or euglycemic on once-daily insulin; and insulin dependent if on standard basal-bolus diabetic regimen. A 36-item Short Form (SF-36) survey for quality of life was completed by patients before and in serial follow-up since 2007, with an integrated survey that was added in 2008. RESULTS Actuarial patient survival post TP-IAT was 96% in adults and 98% in children (1 year) and 89% and 98% (5 years). Complications requiring relaparotomy occurred in 15.9% and bleeding (9.5%) was the most common complication. IAT function was achieved in 90% (C-peptide >0.6 ng/mL). At 3 years, 30% were insulin independent (25% in adults, 55% in children) and 33% had partial function. Mean hemoglobin A1c was <7.0% in 82%. Earlier pancreas surgery lowered islet yield (2,712 vs 4,077/kg; p = 0.003). Islet yield (<2,500/kg [36%]; 2,501 to 5,000/kg [39%]; >5,000/kg [24%]) correlated with degree of function with insulin-independent rates at 3 years of 12%, 22%, and 72%, and rates of partial function 33%, 62%, and 24%. All patients had pain before TP-IAT and nearly all were on daily narcotics. After TP-IAT, 85% had pain improvement. By 2 years, 59% had ceased narcotics. All children were on narcotics before, 39% at follow-up; pain improved in 94%; and 67% became pain-free. In the SF-36 survey, there was significant improvement from baseline in all dimensions, including the Physical and Mental Component Summaries (p < 0.01), whether on narcotics or not. CONCLUSIONS TP can ameliorate pain and improve quality of life in otherwise refractory CP patients, even if narcotic withdrawal is delayed or incomplete because of earlier long-term use. IAT preserves meaningful islet function in most patients and substantial islet function in more than two thirds of patients, with insulin independence occurring in one quarter of adults and half the children.


American Journal of Transplantation | 2011

Revisiting Traditional Risk Factors for Rejection and Graft Loss after Kidney Transplantation

Ty B. Dunn; Harriet Noreen; K. J. Gillingham; David Maurer; O. G. Ozturk; Timothy L. Pruett; Robert A. Bray; Howard M. Gebel; Arthur J. Matas

Single‐antigen bead (SAB) testing permits reassessment of immunologic risk for kidney transplantation. Traditionally, high panel reactive antibody (PRA), retransplant and deceased donor (DD) grafts have been associated with increased risk. We hypothesized that this risk was likely mediated by (unrecognized) donor‐specific antibody (DSA). We grouped 587 kidney transplants using clinical history and single‐antigen bead (SAB) testing of day of transplant serum as (1) unsensitized; PRA = 0 (n = 178), (2) third‐party sensitized; no DSA (n = 363) or (3) donor sensitized; with DSA (n = 46), and studied rejection rates, death‐censored graft survival (DCGS) and risk factors for rejection. Antibody‐mediated rejection (AMR) rates were increased with DSA (p < 0.0001), but not with panel reactive antibody (PRA) in the absence of DSA. Cell‐mediated rejection (CMR) rates were increased with DSA (p < 0.005); with a trend to increased rates when PRA>0 in the absence of DSA (p = 0.08). Multivariate analyses showed risk factors for AMR were DSA, worse HLA matching, and female gender; for CMR: DSA, PRA>0 and worse HLA matching. AMR and CMR were associated with decreased DCGS. The presence of DSA is an important predictor of rejection risk, in contrast to traditional risk factors. Further development of immunosuppressive protocols will be facilitated by stratification of rejection risk by donor sensitization.


American Journal of Transplantation | 2005

A Prospective Randomized Trial of Steroid‐Free Maintenance Regimens in Kidney Transplant Recipients—An Interim Analysis

Raja Kandaswamy; J. Keith Melancon; Ty B. Dunn; Miguel Tan; Vincent Casingal; Abhinav Humar; William D. Payne; Rainer W. G. Gruessner; David L. Dunn; John S. Najarian; David E. R. Sutherland; Kristen J. Gillingham; Arthur J. Matas

We compared three maintenance immunosuppressive regimens in a rapid discontinuation of prednisone protocol. From March 1, 2001, through December 31, 2003, 239 first and second kidney transplant recipients (166 LD; 73 DD) were randomized. All recipients were treated with Thymoglobulin; all received steroids intraoperatively and for 5 days postoperatively. Randomization was to cyclosporine–mycophenolate mofetil (n = 85); high‐level tacrolimus (TAC) (8–12 ng/mL)–low‐level sirolimus (SRL) (3–7 ng/mL) (n = 72); or low‐level TAC (3–7 ng/mL)–high‐level SRL (8–12 ng/mL) (n = 82). We found no difference at 24 months between groups in patient, graft, death‐censored graft, or acute rejection‐free graft survival, or in kidney function.


American Journal of Transplantation | 2004

Outcome at 3 Years with a Prednisone-Free Maintenance Regimen: A Single-Center Experience with 349 Kidney Transplant Recipients

Khalid Khwaja; Massimo Asolati; James V. Harmon; J. Keith Melancon; Ty B. Dunn; Kristen J. Gillingham; Raja Kandaswamy; Abhinav Humar; Rainer W. G. Gruessner; William D. Payne; John S. Najarian; David L. Dunn; David E. R. Sutherland; Arthur J. Matas

Historically, late steroid withdrawal after kidney transplants has been associated with an increased rejection rate. Recently, low rejection rates have been reported for recipients treated with complete avoidance or rapid elimination of steroids. However, follow‐up has been short. We herein report on 3‐year outcome in recipients whose prednisone was rapidly eliminated and who were maintained on a steroid‐free regimen. From 10/1/1999 through 5/1/2003, 349 recipients (254 LD, 95 CAD; 319 in first 30 s) were immunosuppressed with polyclonal antibody (Thymoglobulin), a calcineurin inhibitor, either mycophenolate mofetil or sirolimus, and rapid discontinuation of prednisone.


The New England Journal of Medicine | 2016

Survival Benefit with Kidney Transplants from HLA-Incompatible Live Donors

Babak J. Orandi; Xun Luo; Allan B. Massie; J. M. Garonzik-Wang; Bonnie E. Lonze; Rizwan Ahmed; K. J. Van Arendonk; Mark D. Stegall; Stanley C. Jordan; J. Oberholzer; Ty B. Dunn; Lloyd E. Ratner; Sandip Kapur; Ronald P. Pelletier; John P. Roberts; Marc L. Melcher; Pooja Singh; Debra Sudan; Marc P. Posner; Jose M. El-Amm; R. Shapiro; Matthew Cooper; George S. Lipkowitz; Michael A. Rees; Christopher L. Marsh; Bashir R. Sankari; David A. Gerber; P. W. Nelson; J. Wellen; Adel Bozorgzadeh

BACKGROUND A report from a high-volume single center indicated a survival benefit of receiving a kidney transplant from an HLA-incompatible live donor as compared with remaining on the waiting list, whether or not a kidney from a deceased donor was received. The generalizability of that finding is unclear. METHODS In a 22-center study, we estimated the survival benefit for 1025 recipients of kidney transplants from HLA-incompatible live donors who were matched with controls who remained on the waiting list or received a transplant from a deceased donor (waiting-list-or-transplant control group) and controls who remained on the waiting list but did not receive a transplant (waiting-list-only control group). We analyzed the data with and without patients from the highest-volume center in the study. RESULTS Recipients of kidney transplants from incompatible live donors had a higher survival rate than either control group at 1 year (95.0%, vs. 94.0% for the waiting-list-or-transplant control group and 89.6% for the waiting-list-only control group), 3 years (91.7% vs. 83.6% and 72.7%, respectively), 5 years (86.0% vs. 74.4% and 59.2%), and 8 years (76.5% vs. 62.9% and 43.9%) (P<0.001 for all comparisons with the two control groups). The survival benefit was significant at 8 years across all levels of donor-specific antibody: 89.2% for recipients of kidney transplants from incompatible live donors who had a positive Luminex assay for anti-HLA antibody but a negative flow-cytometric cross-match versus 65.0% for the waiting-list-or-transplant control group and 47.1% for the waiting-list-only control group; 76.3% for recipients with a positive flow-cytometric cross-match but a negative cytotoxic cross-match versus 63.3% and 43.0% in the two control groups, respectively; and 71.0% for recipients with a positive cytotoxic cross-match versus 61.5% and 43.7%, respectively. The findings did not change when patients from the highest-volume center were excluded. CONCLUSIONS This multicenter study validated single-center evidence that patients who received kidney transplants from HLA-incompatible live donors had a substantial survival benefit as compared with patients who did not undergo transplantation and those who waited for transplants from deceased donors. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases.).


American Journal of Transplantation | 2014

Quantifying the Risk of Incompatible Kidney Transplantation: A Multicenter Study

Babak J. Orandi; Jacqueline M. Garonzik-Wang; Allan B. Massie; Andrea A. Zachary; J. R. Montgomery; K. J. Van Arendonk; Mark D. Stegall; Stanley C. Jordan; Jose Oberholzer; Ty B. Dunn; Lloyd E. Ratner; Sandip Kapur; Ronald P. Pelletier; John P. Roberts; Marc L. Melcher; Pooja Singh; Debra Sudan; Marc P. Posner; Jose M. El-Amm; R. Shapiro; Matthew Cooper; George S. Lipkowitz; Michael A. Rees; Christopher L. Marsh; B. R. Sankari; David A. Gerber; P. W. Nelson; Jason R. Wellen; Adel Bozorgzadeh; A. O. Gaber

Incompatible live donor kidney transplantation (ILDKT) offers a survival advantage over dialysis to patients with anti‐HLA donor‐specific antibody (DSA). Program‐specific reports (PSRs) fail to account for ILDKT, placing this practice at regulatory risk. We collected DSA data, categorized as positive Luminex, negative flow crossmatch (PLNF) (n = 185), positive flow, negative cytotoxic crossmatch (PFNC) (n = 536) or positive cytotoxic crossmatch (PCC) (n = 304), from 22 centers. We tested associations between DSA, graft loss and mortality after adjusting for PSR model factors, using 9669 compatible patients as a comparison. PLNF patients had similar graft loss; however, PFNC (adjusted hazard ratio [aHR] = 1.64, 95% confidence interval [CI]: 1.15–2.23, p = 0.007) and PCC (aHR = 5.01, 95% CI: 3.71–6.77, p < 0.001) were associated with increased graft loss in the first year. PLNF patients had similar mortality; however, PFNC (aHR = 2.04; 95% CI: 1.28–3.26; p = 0.003) and PCC (aHR = 4.59; 95% CI: 2.98–7.07; p < 0.001) were associated with increased mortality. We simulated Centers for Medicare & Medicaid Services flagging to examine ILDKTs effect on the risk of being flagged. Compared to equal‐quality centers performing no ILDKT, centers performing 5%, 10% or 20% PFNC had a 1.19‐, 1.33‐ and 1.73‐fold higher odds of being flagged. Centers performing 5%, 10% or 20% PCC had a 2.22‐, 4.09‐ and 10.72‐fold higher odds. Failure to account for ILDKTs increased risk places centers providing this life‐saving treatment in jeopardy of regulatory intervention.


American Journal of Transplantation | 2008

2202 kidney transplant recipients with 10 years of graft function: what happens next?

Arthur J. Matas; Kristen J. Gillingham; Abhinav Humar; Raja Kandaswamy; David E. R. Sutherland; William D. Payne; Ty B. Dunn; John S. Najarian

The ultimate goal of clinical transplantation is for the recipients to achieve long‐term survival, with continuing graft function, that is equivalent to that of the age‐matched general population. We studied subsequent outcome in kidney transplant recipients with 10 years of graft function. In all, 2202 kidney transplant recipients survived with graft function >10 years. For 10‐year survivors, the actuarial 25‐year patient survival rate for primary transplant living donor (LD) recipients was 57%; graft survival, 43%. For primary transplant deceased donor (DD) recipients, the actuarial 25‐year patient survival rate was 39%; graft survival, 27%. The two major causes of late graft loss were death (with graft function) and chronic allograft nephropathy (tubular atrophy and interstitial fibrosis). The two major causes of death with function were cardiovascular disease (CVD) and malignancy. For nondiabetic recipients, the mean age at death with function from CVD was 54 ± 13 years; for diabetic recipients, 53 ± 7 years. By 20 years posttransplant, morbidity was common: >40% recipients had skin cancer (mean age for nondiabetic recipients, 53 ± 13 years; for diabetics, 49 ± 8 years), >10% had non‐skin cancer (mean age for nondiabetic recipients, 53 ± 16 years; for diabetics, 46 ± 9 years), and >30% had CVD (mean age for nondiabetic recipients, 53 ± 15 years; for diabetics, 47 ± 9 years). We conclude that long‐term transplant recipients have a high rate of morbidity and early mortality. As short‐term results have improved, more focus is needed on long‐term outcome.


Clinical Gastroenterology and Hepatology | 2011

Quality of Life Improves for Pediatric Patients After Total Pancreatectomy and Islet Autotransplant for Chronic Pancreatitis

Melena D. Bellin; Martin L. Freeman; Sarah Jane Schwarzenberg; Ty B. Dunn; Gregory J. Beilman; Selwyn M. Vickers; Srinath Chinnakotla; A. N. Balamurugan; Bernhard J. Hering; David M. Radosevich; Antoinette Moran; David E. R. Sutherland

BACKGROUND & AIMS Total pancreatectomy (TP) and islet autotransplant (IAT) have been used to treat patients with painful chronic pancreatitis. Initial studies indicated that most patients experienced significant pain relief, but there were few validated measures of quality of life. We investigated whether health-related quality of life improved among pediatric patients undergoing TP/IAT. METHODS Nineteen consecutive children (aged 5-18 years) undergoing TP/IAT from December 2006 to December 2009 at the University of Minnesota completed the Medical Outcomes Study 36-item Short Form (SF-36) health questionnaire before and after surgery. Insulin requirements were recorded. RESULTS Before TP/IAT, patients had below average health-related quality of life, based on data from the Medical Outcomes Study SF-36; they had a mean physical component summary (PCS) score of 30 and mental component summary (MCS) score of 34 (2 and 1.5 standard deviations, respectively, below the mean for the US population). By 1 year after surgery, PCS and MCS scores improved to 50 and 46, respectively (global effect, PCS P < .001, MCS P = .06). Mean scores improved for all 8 component subscales. More than 60% of IAT recipients were insulin independent or required minimal insulin. Patients with prior surgical drainage procedures (Puestow) had lower yields of islets (P = .01) and greater incidence of insulin dependence (P = .04). CONCLUSIONS Quality of life (physical and emotional components) significantly improve after TP/IAT in subsets of pediatric patients with severe chronic pancreatitis. Minimal or no insulin was required for most patients, although islet yield was reduced in patients with previous surgical drainage operations.


Annals of Surgery | 2014

Total pancreatectomy and islet autotransplantation in children for chronic pancreatitis: Indication, surgical techniques, postoperative management, and long-term outcomes

Srinath Chinnakotla; Melena D. Bellin; Sarah Jane Schwarzenberg; David M. Radosevich; Marie Cook; Ty B. Dunn; Gregory J. Beilman; Martin L. Freeman; A. N. Balamurugan; Josh Wilhelm; Barbara Bland; Jose M. Jimenez-Vega; Bernhard J. Hering; Selwyn M. Vickers; Timothy L. Pruett; David E. R. Sutherland

Objective:Describe the surgical technique, complications, and long-term outcomes of total pancreatectomy and islet autotransplantation (TP-IAT) in a large series of pediatric patients. Background:Surgical management of childhood pancreatitis is not clear; partial resection or drainage procedures often provide transient pain relief, but long-term recurrence is common due to the diffuse involvement of the pancreas. Total pancreatectomy (TP) removes the source of the pain, whereas islet autotransplantation (IAT) potentially can prevent or minimize TP-related diabetes. Methods:Retrospective review of 75 children undergoing TP-IAT for chronic pancreatitis who had failed medical, endoscopic, or surgical treatment between 1989 and 2012. Results:Pancreatitis pain and the severity of pain statistically improved in 90% of patients after TP-IAT (P < 0.001). The relief from narcotics was sustained. Of the 75 patients undergoing TP-IAT, 31 (41.3%) achieved insulin independence. Younger age (P = 0.032), lack of prior Puestow procedure (P = 0.018), lower body surface area (P = 0.048), higher islet equivalents (IEQ) per kilogram body weight (P = 0.001), and total IEQ (100,000) (P = 0.004) were associated with insulin independence. By multivariate analysis, 3 factors were associated with insulin independence after TP-IAT: (1) male sex, (2) lower body surface area, and (3) higher total IEQ per kilogram body weight. Total IEQ (100,000) was the single factor most strongly associated with insulin independence (odds ratio = 2.62; P < 0.001). Conclusions:Total pancreatectomy and islet autotransplantation provides sustained pain relief and improved quality of life. The &bgr;-cell function is dependent on islet yield. Total pancreatectomy and islet autotransplantation is an effective therapy for children with painful pancreatitis that failed medical and/or endoscopic management.


Clinical Journal of The American Society of Nephrology | 2012

Ten-Year Outcome after Rapid Discontinuation of Prednisone in Adult Primary Kidney Transplantation

Michael D. Rizzari; Thomas M. Suszynski; Kristen J. Gillingham; Ty B. Dunn; Hassan N. Ibrahim; William D. Payne; Srinath Chinnakotla; Erik B. Finger; David E. R. Sutherland; Raja Kandaswamy; John S. Najarian; Timothy L. Pruett; Aleksandra Kukla; Richard Spong; Arthur J. Matas

BACKGROUND AND OBJECTIVES Rapid discontinuation of prednisone after kidney transplantation potentially allows for minimization of steroid-related side effects. Although intermediate-term data with rapid discontinuation of prednisone have been promising, concern still exists regarding long-term outcomes. The 10-year experience is reported herein. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Between October 1, 1999 and December 31, 2010, 1241 adult primary kidney transplants (791 living donor and 450 deceased donor) were performed using a protocol in which prednisone is discontinued after postoperative day 5. The 10-year actuarial recipient and graft survival rates and prednisone-related side effects were studied. RESULTS Ten-year actuarial patient survival was 71% for living donor transplants and 62% for deceased donor transplants; 10-year graft survival was 61% for living donor transplants and 51% for deceased donor transplants, and was comparable to 10-year Scientific Registry of Transplant Recipients national data. Ten-year death-censored graft survival was 79% for living donor transplants and 80% for deceased donor transplants. Ten-year acute rejection rates were 25% for deceased donor transplants and 31% for living donor transplants; 10-year chronic rejection (interstitial fibrosis/tubular atrophy) rates were 39% for deceased donor transplants and 47% for living donor transplants. For nondiabetic recipients of living donor or deceased donor allografts, the incidence of new-onset diabetes was significantly lower than in historical controls on prednisone (P<0.001). We also found significantly reduced rates of cataracts, avascular necrosis, and cytomegalovirus infection in some subgroups. CONCLUSIONS Prednisone-related side effects can be minimized in a protocol incorporating rapid discontinuation of prednisone for maintenance immunosuppression. Ten-year patient and graft outcomes remain acceptable.

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