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Abhinav Humar

Publications and source records attributed to Abhinav Humar.

At least 37 records · Page 2Linked to original sources
PubMed2004

Long-term immunosuppression, without maintenance prednisone, after kidney transplantation.

BACKGROUND: Concern exists that prednisone-free maintenance immunosuppression in kidney transplant recipients will increase acute and/or chronic rejection. METHODS: From October 1, 1999, through February 29, 2004, at our center, 477 kidney transplant recipients (341 living donor, 136 cadaver) discontinued prednisone on postoperative day 6, per our protocol. Immunosuppression consisted of polyclonal antibody (Thymoglobulin) for 5 days, prednisone intraoperatively and for 5 days, a calcineurin inhibitor, and either sirolimus or mycophenolate mofetil. We compared outcome with that of historical controls who did not discontinue prednisone. RESULTS: The recipients on prednisone-free maintenance immunosuppression had excellent 4-year actuarial patient survival (92%), graft survival (90%), acute rejection-free graft survival (86%), and chronic rejection-free graft survival (95%). The mean serum creatinine level (+/- SD) at 1 year was 1.6 +/- 0.6; at 4 years, 1.6 +/- 0.6. We noted that 8% of recipients had cytomegalovirus (CMV) disease; 4.5%, fractures; 2.8%, cataracts; 1%, posttransplant diabetes; 0.2%, avascular necrosis; 0.2%, posttransplant lymphoproliferative disease; and 0%, polyomavirus. In all, 85% of kidney recipients with functioning grafts remain prednisone-free as of April 1, 2004. As compared with historical controls, the recipients on prednisone-free maintenance immunosuppression had better patient (P = 0.02) and graft survival (P < 0.0001) and lower rates of acute (P = 0.0004) and chronic (P = 0.02) rejection. In addition, they had a significantly lower rate of CMV disease (P < 0.0001), cataracts (P < 0.0001), posttransplant diabetes (P < 0.0001), and avascular necrosis (P = 0.0003). CONCLUSIONS: Prednisone-related side effects can be minimized without maintenance immunosuppression; our prednisone-free recipients do not have increased acute or chronic rejection.

Adult↗
PubMed2004

The impact of donor obesity on outcomes after cadaver pancreas transplants.

We examined the impact of donor obesity on surgical complications and graft function after pancreas transplants. From January 1994 through December 2001, we performed 711 cadaver pancreas transplants. We analyzed outcomes for three groups based on donor body mass index (BMI): <25 kg/m2 (n=434), 25-30 (n=196), and >30 (n=81). Donor characteristics were similar between the three groups except for donor cause of death. Cerebrovascular deaths were more common in the BMI >30 group (p=0.002), while trauma deaths were more common in the BMI <25 group (p=0.02). In the BMI >30 group, surgical complications, most notably surgical infections and thrombosis, were significantly more common; in addition, technical failure rates were higher and short-term graft survival was inferior. The incidence of technical failure was 9.7% in the BMI <25 group, 16.3% in the BMI 25-30 group, and 21.0% in the BMI >30 group (p=0.04). However, when we looked at only technically successful transplants, we found minimal differences in the three groups with regard to graft survival at 1 and 3 years posttransplant. Donor obesity increased the incidence of surgical complications in our pancreas recipients, but did not affect initial graft function posttransplant. Technically successful transplants using obese donors results in good graft function at 1 and 3 years posttransplant.

Age Factors↗
PubMed2004

Risk factors and impact of delayed graft function after pancreas transplants.

Delayed graft function (DGF) occurs after many pancreas transplants (PTx), but is poorly characterized. We studied its incidence, course, and impact in a series of 531 pancreas transplants. Between January 1997 and September 2002, we performed 531 technically successful primary PTx. Of these 531 recipients, 176 (33%) had DGF, defined by their need for exogenous insulin at the time of hospital discharge. The incidence of DGF was roughly equivalent in the three transplant categories: SPK (36%), PAK (32%), and PTA (31%) (p = NS). By 3 months posttransplant, only 19 (3.5%) of all recipients remained on insulin. Only three recipients (0.56%) did not achieve insulin independence. The mean donor age of recipients with DGF was 35.1 years vs. 28.8 years without DGF (p = 0.003). By multivariate analysis, the most significant risk factor for DGF was donor age > 45 years (RR = 4.3, p = 0.0001). For SPK recipients with DGF, graft survival was 87% at 1 year and 82% at 3 years posttransplant; without DGF, 94% at 1 year and 87% at 3 years (p = 0.07). For PAK and PTA recipients, no difference was noted. Acute rejection rates were somewhat higher in recipients with DGF, but this did not reach statistical significance.

Adult↗
PubMed2004

Outcome at 3 years with a prednisone-free maintenance regimen: a single-center experience with 349 kidney transplant recipients.

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. Actuarial 3-year patient survival was 95%; graft survival, 93%. Acute rejection-free graft survival at 1 year was 94%; at 3 years, 92%. There was no difference between LD and CAD. At 2 years, the mean (+/- SE) serum creatinine level for LDs was 1.6 +/- 0.5 mg/dL; for CAD, 1.6 +/- 0.4 mg/dL. We have no new cases of PTLD or avascular necrosis; 22 recipients (6%) developed CMV. Currently, 84% of recipients remain prednisone-free. We conclude that excellent 3-year patient and graft survival can be achieved without maintenance prednisone. With such a protocol, steroid-related side-effects are minimal.

Antilymphocyte Serum↗
PubMed2003

Chronic rejection: the next major challenge for pancreas transplant recipients.

OBJECTIVE: With newer immunosuppressive agents, acute rejection and graft loss resulting from acute rejection have become less common for pancreas transplant recipients. As long-term graft survival rates have improved, an increasing number of grafts are being lost to chronic rejection (CR). We studied the incidence of CR and identified risk factors. METHODS: We retrospectively analyzed all cadaver pancreas transplants performed at the University of Minnesota between June 19, 1994, and December 31, 2002. We determined the causes of graft loss, the incidence of graft loss to CR and, using multivariate techniques, the major risk factors for CR. RESULTS: A total of 914 cadaver pancreas transplants were performed in the following three categories: simultaneous pancreas-kidney (SPK) (n=321), pancreas after kidney (PAK) (n=389), and pancreas transplant alone (PTA) (n=204). The mean recipient age was 41.3 years and the mean donor age was 30.1 years. Of the 914 pancreas grafts, 643 (70.3%) continue to function (mean length of follow-up, 39 months). The most common cause of graft loss was technical failure, accounting for 118 (12.9%) of the failed grafts. The second most common cause was CR, accounting for 80 (8.8%) of the failed grafts. The incidence of graft loss to CR was highest for PTA (n=23 [11.3%]) and PAK (n=45 [11.6%]) recipients and lowest for SPK recipients (n=12 [3.7%]) (P=0.002). By multivariate analysis, the most significant risk factors for graft loss to CR were a previous episode of acute rejection (relative risk [RR]=4.41, P<0.0001), an isolated (vs. simultaneous) transplant (PAK or PTA [vs. SPK], RR=3.02, P=0.002), cytomegalovirus infection posttransplant (RR=2.41, P=0.001), a retransplant (versus primary transplant) (RR=2.27, P=0.004), and one or two (vs. zero) antigen mismatches at the B loci (RR=1.68, P=0.04). CONCLUSIONS: As short-term pancreas transplant results improve and as isolated (PAK or PTA) pancreas transplants gain in popularity, CR will become increasingly common as a cause of pancreas graft loss.

Acute Disease↗
PubMed2003

Predicting long-term kidney graft survival: can new trials be performed?

BACKGROUND: As short-term transplant results improve, it has become difficult to use patient or graft survival or acute rejection as clinical trial endpoints, except in large, multicenter studies. Despite better outcomes, graft failure continues over time. METHODS: We studied 6- and 12-month creatinine (Cr) level and change in creatinine (deltaCr) level (3-12 months, 6-12 months) as predictors of graft survival for 1,389 primary kidney transplants (minimum graft survival 1 year). Determining the prognostic value of Cr level (6 or 12 months), the subgroups were as follows: less than 1, 1 to 1.4, 1.5 to 1.9, 2.0 to 2.4, 2.5 to 2.9, and greater than or equal to 3 mg/dL. For deltaCr level, the subgroups were as follows: less than 0, 0, 0.01 to 0.2, and greater than 0.2. Subgroup actuarial graft survival was determined. Cox regression analyses were performed with forward, stepwise selection. RESULTS: After 12-month Cr level entered the model, no other variable was significant. Repeating this with continuous variables, 12-month Cr level was again the best predictor. Five-year graft survival for 12-month Cr level less than 1 (n=38) was 95%; for 1.0 to 1.4 (n=454), 87%; for 1.5 to 1.9 (n=463), 86%; for 2.0 to 2.4 (n=166), 78%; for 2.5 to 2.9 (n=54), 60%; for greater than or equal to 3 (n=45), 41%. A major breakpoint for outcome is 1-year Cr level=2.0. A power analysis was performed for the combined endpoint of graft loss and 1-year Cr level greater than 2, reached by 30% of patients. To avoid missing a reduction to 20% (actual decrease 33%) (alpha=0.05; power=0.8), 313 patients would be required per group. For a reduction to 15% (actual decrease 50%), 133 patients would be required. CONCLUSIONS: Twelve-month Cr level is an accurate surrogate for long-term outcome. The use of a combined endpoint (graft loss and 12-month Cr level) allows trials to be performed without exorbitant numbers.

Azathioprine↗
PubMed2003

Pancreas transplantation in crossmatch-positive recipients.

BACKGROUND: Prolonged cold preservation time can unfavorably affect outcome in pancreas transplantation. To reduce this ischemic time, cadaver pancreas grafts, in selected cases, are sometimes transplanted before crossmatch results are known. We report our experience with pancreas transplants in recipients with either current or historically positive T- or B-cell crossmatches. METHODS: Crossmatch-positive pancreas transplants were identified using a computerized database. T-cell crossmatches were performed using an antihuman-globulin-augmented complement-dependent cytotoxicity (CDC) test; B-cell crossmatches were performed using an extended incubation CDC test. All patients received anti-T-cell induction therapy and either cyclosporine (1987-1993) or tacrolimus-based (1994-2001) immunosuppression. More recent recipients (2000-2001) also received intravenous gamma globulin and postoperative plasmapheresis. RESULTS: Between October 1, 1987 and March 31, 2001, of a total of 1076 pancreas transplants performed, 59 (5.48%) were crossmatch-positive. Of these, 8 had a current T-cell-positive crossmatch and 15 had a current B-cell-positive crossmatch. One recipient was both current B- and T-positive, and the rest were past B- and/or T-cell positive. One-year pancreas graft survival for current T- and B-cell crossmatch-positive transplants was 63% and 67%, respectively. T- or B-cell crossmatch-negative transplants had a 1-yr survival of 70%. In the T-cell crossmatch-positive group, four grafts are still functioning (follow-up range, 2-12 yr), one patient died with a functioning graft at 4 months, and four grafts failed (one each from pancreatitis, infection, primary nonfunction, and vascular thrombosis). No grafts were lost to rejection. In the B-cell crossmatch-positive group, six grafts are still functioning (follow-up range, 2-11 yr) and nine have failed (four from chronic rejection, three from vascular thromboses, and two from pancreatitis). Crossmatch-positive cases were significantly more likely to be retransplants (70.8%) than crossmatch-negative cases (14.8%, p < 0.0001). In a multivariate analysis, crossmatch positivity did not affect pancreas graft outcome, whereas retransplants had a significant impact on outcome (relative risk 1.84, p < 0.0001). CONCLUSIONS: (: i) Pancreas transplants performed in the setting of a positive current crossmatch may have long-term function. (ii) With current immunosuppressive protocols, graft loss from hyperacute and acute rejection may be prevented in current crossmatch-positive pancreas transplants. Chronic rejection was only seen in B-cell crossmatch-positive cases. (iii) High rates of technical graft loss in crossmatch-positive cases may reflect a high frequency of retransplants in this group.

B-Lymphocytes↗
PubMed2003

Radiofrequency ablation causes 'thermal fixation' of hepatocellular carcinoma: a post-liver transplant histopathologic study.

Radiofrequency ablation (RFA) is increasingly used to treat hepatocellular carcinoma (HCC) in patients awaiting a liver transplant. Despite its increasing use, detailed histologic information is scarce regarding the nature of RFA-treated lesions. We identified four chronic hepatitis C patients who had RFA of their HCC before their liver transplant. For these four patients, we conducted a detailed histopathologic analysis of the treated lesions in their explanted livers. The five lesions included immediate (4 d) and long-term (14 months) post-RFA specimens. Of the five lesions, four were completely ablated. The one incompletely ablated lesion was also treated with chemoembolization. In the acute post-RFA period, a zone of interstitial hemorrhage occurred at the outer boundary of the lesion. Differing from classic tissue necrosis, the treated lesions all showed 'thermal fixation', with preserved tissue architecture and microscopic cellular detail. The cellular staining characteristics faded with time, but the treated tissue became brittle, resisted tissue breakdown, and generated a minimal wound healing response. At the periphery of the lesion, the fibrous septae of the cirrhotic liver and vascular structures appeared to demarcate or limit progression of the ablation front. A narrow hypocellular fibrous boundary with a focal 'foreign body' giant cell-type reaction developed around the edge of the ablation zone. Thus, RFA can produce immediate and complete thermal fixation of select lesions with an appropriate liver margin and can provide a satisfactory treatment option for select HCC patients before a liver transplant.

Carcinoma, Hepatocellular↗
PubMed2003

Kidney transplants for children under 1 year of age - a single-center experience.

From September 20, 1970 to October 24, 2001, we performed 46 kidney transplants in infants under 1 yr old at the University of Minnesota. This article reviews the preoperative care, surgical technique, and immunosuppression. Recipients included 16 females and 30 males; the youngest recipient was 6 wk old. The mean pretransplant height was 62.8 cm, which increased to 77 cm at 1 yr post-transplant and to 104 cm at 5 yr. We used 40 living donors (all but 1 were related to the recipient) and 6 cadaver donors. The overall actuarial graft survival was 85% at 1 yr and 70% at 5 yr. In the cyclosporine era, graft survival improved to 91% at 1 yr and 80% at 5 yr. Death with function was the most common cause of graft loss (n = 5), followed by biopsy-proven chronic rejection (n = 4), biopsy-proven recurrent disease (n = 3), and graft thrombosis (n = 2). Patient survival was 91% at 1 yr and 86% at 5 yr. In the cyclosporine era, patient survival was 100% at 5 yr and 85% at 10 yr. We concluded that an early transplant is the best treatment option for infants under 1 yr old with chronic renal failure. Whenever possible, adult living kidney donors should be used.

Cadaver↗
PubMed2003

Graft and quality of life outcomes in older recipients of a kidney transplant.

BACKGROUND: It is well recognized that kidney transplants significantly improve quality of life for patients with end-stage renal disease (ESRD). This benefit is not as clearly documented for older recipients as it is for younger recipients. We looked at outcomes, both medical and psychosocial, in a group of older (> or =65 years) kidney transplant recipients and compared the results to a group of younger recipients (18 to 64 years). METHODS: From 1990 through 2002, we performed 2,746 kidney transplants at our center: 2,596 (94.5%) in recipients 18 to 64 years old and 150 (5.5%) in recipients 65 years or older. In our retrospective analysis, we determined outcomes such as patient and graft survival rates. To determine whether or not older recipients had an improved health-related quality of life, we used the national SF-36 (short form) questionnaire. We compared those results with a group of younger recipients and with national age-appropriate norms. RESULTS: The mean recipient age was 69.1 years in the older group vs. 42.8 years in the younger group (p < 0.001). Living donors were used in 43.3% of the transplants in the older group vs. 47.5% in the younger group (p < 0.01). At 5 years posttransplant, patient and graft survival rates were 73% and 68% in the older group vs. 86% and 79% in the younger group (p < 0.001). We analyzed the SF-36 responses for all recipients with completed forms: 42 completed forms from the older group vs. 149 from the younger group. The overall benefit to quality of life was similar for both groups. General physical health was rated slightly higher than national norms in both groups. Benefits to mental health were more pronounced in the older group. CONCLUSION: Kidney transplants can be performed in older recipients with acceptable outcomes. Such recipients enjoy significant benefits to their quality of life after a transplant, similar to benefits seen in younger recipients. Older age, by itself, should not be a contraindication to a transplant.

Adult↗
PubMed2002

Living related liver transplantation for recurrent hepatocellular carcinoma in a normal liver.

The role of liver transplantation for hepatocellular carcinoma (HCC) is evolving. In patients with advanced liver disease and early stage HCC, transplantation offers the best hope for cure. A living donor offers the optimal approach to a timely transplant, before disease progression obviates the potential benefit. But extending the indications beyond those designated by the United Network for Organ Sharing (UNOS) for liver transplantation for HCC is controversial [Hepatology 2001: 33: 1073; Liver Transplant 2000: 6: S1]. Cadaver split techniques and use of living donors are potentially compelling ways to test the limitations of liver transplantation for HCC, without notably reducing the cadaver organ pool. Herein, we report a rare case of a patient who developed a well-differentiated HCC in a normal liver. After resection of the index lesion and, later, of a remote recurrent lesion, a living donor liver transplant was offered. The natural history of this lesion and the management of transplantation in this setting are discussed.

Adult↗
PubMed2002

Biliary stricture in living-related donor liver transplantation: management with balloon dilation.

Biliary stricture is a recipient graft complication, occurring late in the post-operative period, which appears to occur with increased frequency in living-related donor liver transplantation (LRD LTx). We reviewed the experience at the University of Minnesota in managing a biliary complication of LRD LTx. Since January 1997, 13 LRD transplants have been performed using the technique of transplantation of the left lateral segments with a small portion of segment IV. All patients had hepaticojejunostomies using a Roux-en-Y loop. Of the 11 surviving patients, eight had evidence of cholangitis (Gram-negative sepsis, two patients; ascending cholangitis, three patients; or unexplained fever with elevated liver enzymes, three patients) 4-8 months after otherwise successful transplantation. Six of the patients underwent percutaneous transhepatic cholangiography (PTC) with demonstration of a stenosis at the site of the biliary anastomosis. Repeated dilation of the anastomosis led to resolution of the stenoses, normalization of liver enzymes, and prevention of further episodes of infection. No patient required revision of the hepaticojejunostomy. Computed axial tomography evidence of ductal stenosis may be subtle in this group of patients, but PTC is diagnostic. We suggest a high index of suspicion of biliary stricture in the LRD LTx population. Biliary dilation reduces the risk of life-threatening sepsis.

Catheterization↗
PubMed2002

Five preventable causes of kidney graft loss in the 1990s: a single-center analysis.

BACKGROUND: Despite improvements in immunosuppressive protocols and patient care, kidney allografts continue to fail. We studied causes of graft loss for primary kidney transplants in the 1990s to determine major causes and potential interventions. METHODS: Causes of graft loss were reviewed for 1467 primary kidney transplants done at our institution between January 1, 1990, and December 31, 1999. Graft loss for that entire population was studied and then the causes of loss selectively examined at <1 year, 1 to 5 years, and>5 years post-transplant. Finally, causes of loss in the 1990s versus the 1980s were compared. RESULTS: Five major causes of graft loss were noted in the 1990s: thrombosis, acute rejection (either alone or combined with delayed graft function or infection), chronic rejection, death with function, and noncompliance. In the first year post-transplant, thrombosis (25%) and death with function (41%) were the major causes of graft loss. After the first year, chronic rejection and death with function predominated. For recipients dying with graft function, cardiovascular disease was the major cause of death. CONCLUSIONS: This study identified the five major causes of kidney graft loss in the 1990s. Different interventions are required to decrease loss from each of these causes. Future research needs to be directed at such interventions.

Acute Disease↗
PubMedDate not supplied

Postoperative severe microangiopathic hemolytic anemia associated with a giant hepatic cavernous hemangioma.

Complications related to liver hemangioma are rare. We herein describe the case of a patient with three giant cavernous hemangiomas of the liver, of which two were resected for symptoms. A significant microangiopathic hemolytic anemia occurred in the early postoperative period, leading to acute renal failure and necessitating blood transfusions. The systematic evaluation of hemolytic processes in the postoperative patient is described. Surgeons should be aware of the potential for hemolytic complications after major surgery when giant hepatic hemangiomas are present.

Anemia, Hemolytic↗