Venkatesh Krishnamurthi

The impact of sirolimus, mycophenolate mofetil, cyclosporine, azathioprine, and steroids on wound healing in 513 kidney-transplant recipients

Background. The aim of this study was to determine whether there has been an increase in the incidence or severity of wound-healing complications that can be attributed to the introduction of newer immunosuppressive drugs. Methods. Consecutive series of adult kidney-only transplant recipients were selected from our Unified Transplant Database backward from September 2002. There were 513 patients divided into groups on the basis of their maintenance immunosuppression given for at least the first 30 days posttransplant. Group I (152) was given sirolimus, mycophenolate mofetil, and prednisone (SRL/MMF/P) between March 2000 and September 2002; group II (168) was given cyclosporine A (CsA)/MMF/P between January 1999 and July 2002; and group III (193) was given azathioprine (AzA)/CsA/P between January 1993 and December 1997. A classification system for wound-healing problems was developed, and each of the three groups was analyzed by univariate and multivariate analysis. Results. From groups III to II to I, there was a significant increase in mean age (42.4 vs. 49 years), percent of patients diabetic (17% vs. 29%), mean body mass index (BMI) (24.2 vs. 27.1 kg/m2), and percent BMI greater than 30 (13.5% vs. 27%). The cumulative percentage of all wound-healing problems between group I (19.7%) vs. group II (16.1%) and group III (15.6%) was not significantly different. The most significant risk factor was a recipient BMI greater than 30 (P =0.0012) and delayed graft function (P =0.0041). Conclusions. During a 10-year period marked by changing recipient demographics, the introduction of MMF and SRL did not result in a significant increase in transplant wound-healing complications. The most significant risk factor associated with transplant wound-healing complications remains body weight, which was the major influence for each of the immunosuppressive drug combinations described.

Donor Kidney Volume and Outcomes Following Live Donor Kidney Transplantation

Pre‐donation kidney volume and function may be crucial factors in determining graft outcomes in kidney transplant recipients. We measured living donor kidney volumes by 3D helical computed tomography scanning and glomerular filtration rate (GFR) by 125I‐iothalamate clearances in 119 donors, and correlated these values with graft function and incidence of acute rejection at 2 years post‐transplantation. Kidney volume strongly correlated with GFR (Pearson r= 0.71, p < 0.001). Body size and male gender were independent correlates of larger kidney volumes, and body size and age were predictors of kidney function. The effects of transplanted kidney volume on graft outcome were studied in 104 donor‐recipient pairs. A transplanted kidney volume greater than 120 cc/1.73 m2 was independently associated with better estimated GFR at 2 years post‐transplant when compared to recipients of lower transplanted kidney volumes (64 ± 19 vs. 48 ± 14 mL/min/1.73 m2, p < 0.001). Moreover, recipients of lower volumes had a higher incidence of acute cellular rejection (16% vs. 3.7%, p = 0.046). In conclusion, kidney volume strongly correlates with function in living kidney donors and is an independent determinant of post‐transplant graft outcome. The findings suggest that (1) transplantation of larger kidneys confers an outcome advantage and (2) larger kidneys should be preferred when selecting from otherwise similar living donors.

Demographic and clinical characteristics associated with glomerular filtration rates in living kidney donors.

Due to the shortage of organs, living donor acceptance criteria are becoming less stringent. An accurate determination of the glomerular filtration rate (GFR) is critical in the evaluation of living kidney donors and a value exceeding 80 ml/min per 1.73 m(2) is usually considered suitable. To improve strategies for kidney donor screening, an understanding of factors that affect GFR is needed. Here we studied the relationships between donor GFR measured by (125)I-iothalamate clearances (mGFR) and age, gender, race, and decade of care in living kidney donors evaluated at the Cleveland Clinic from 1972 to 2005. We report the normal reference ranges for 1057 prospective donors (56% female, 11% African American). Females had slightly higher mGFR than males after adjustment for body surface area, but there were no differences due to race. The lower limit of normal for donors (5th percentile) was less than 80 ml/min per 1.73 m(2) for females over age 45 and for males over age 40. We found a significant doubling in the rate of GFR decline in donors over age 45 as compared to younger donors. The age of the donors and body mass index increased over time, but their mGFR, adjusted for body surface area, significantly declined by 1.49+/-0.61 ml/min per 1.73 m(2) per decade of testing. Our study shows that age and gender are important factors determining normal GFR in living kidney donors.

Surgical Resection of Renal Cell Carcinoma After Targeted Therapy

PURPOSE The development of targeted agents for renal cell carcinoma has renewed interest in consolidative surgery due to the robust clinical responses seen with these agents. The integration of targeted therapy and surgery requires careful consideration due to the potential for increased perioperative morbidity. MATERIALS AND METHODS We retrospectively identified patients with renal cell carcinoma treated with sunitinib, sorafenib or bevacizumab plus interleukin-2 before tumor resection. RESULTS Between June 2005 and August 2008, 19 patients were treated with targeted therapy and subsequently underwent resection. Surgical extirpation involved an open and a laparoscopic approach in 18 and 3 cases, respectively, for locally advanced (8), locally recurrent (6) and metastatic disease (3). Two patients with extensive bilateral renal cell carcinoma were also treated to downsize the tumors to enable partial nephrectomy. Perioperative complications were noted in 16% of patients. One patient had a significant intraoperative hemorrhage and disseminated intravascular coagulopathy from a concomitant liver resection. An anastomotic bowel leak and abscess were noted postoperatively in another patient who underwent en bloc resection of a retroperitoneal recurrence and adjacent colon. Two patients (11%) had minor wound complications, including a wound seroma and a ventral hernia. Pathological analysis of 20 specimens revealed clear cell, chromophobe and unclassified renal cell carcinoma in 80%, 5% and 10% of cases, respectively. One patient (5%) had a pathological complete response. CONCLUSIONS Surgical resection of renal cell carcinoma after targeted therapy is feasible with low morbidity in most patients. However, significant complications can occur, raising concern for possible compromise of tissue and/or vascular integrity associated with surgery in this setting.

Utility of leflunomide in the treatment of complex cytomegalovirus syndromes.

Background. Cytomegalovirus (CMV) viremia that is resistant or refractory to the standard antiviral therapy still constitutes a major threat to high-risk transplant recipients. In addition, multiple CMV recurrences may lead to neutropenia because of repeated courses of therapy with ganciclovir derivatives. Leflunomide, a drug for rheumatoid arthritis, has been reported to have anti-CMV activity. This study reports on its use in 17 transplant recipients with complex CMV syndromes who had failed or were intolerant to other therapies. Methods. Single-center, retrospective study. Clinical data were extracted from the electronic medical record. CMV DNA viral loads were performed by quantitative hybrid capture assay. Results. Leflunomide was initiated after a median of three episodes of CMV viremia, with a mean peak viral load of 245,826 copies/mL. Initial clearance of CMV viremia was observed in 14 of 17 patients (82%), and 9 of 17 (53%) patients achieved a long-term suppression of CMV recurrences. Higher peak viral load and higher viral load at the start of leflunomide therapy were associated with failure to suppress viremia. The duration of leflunomide therapy ranged from 1 to 24 months (median 3.5 months, interquartile range 2.6–7 months), and the mean time to an undetectable CMV-DNA was 1.9 months. Adverse effects included diarrhea (35%), anemia (18%), and increased liver function tests (12%). Conclusions. Leflunomide, alone or in combination, has potential utility in treatment of complex CMV syndromes and in long-term suppression of viremia. The optimal duration of therapy and the balance of risks and benefits are not yet known.

Utility of preoperative renal artery embolization for management of renal tumors with inferior vena caval thrombi.

OBJECTIVES To review our experience with radical nephrectomy and inferior vena cava thrombectomy (RNIVCT) to determine the utility of preoperative embolization. Preoperative embolization has been used as an adjunctive procedure to facilitate surgical resection of complex renal tumors. METHODS From 1990 to 2007, 225 patients with renal tumors and inferior vena cava thrombus underwent RNIVCT, including 135 patients who had undergone preoperative renal artery embolization and 90 patients who had not. The effect of embolization on perioperative morbidity and mortality, transfusion requirements, blood loss, and operative time was analyzed by comparing the 2 groups. RESULTS The mean primary tumor size was similar in both groups; however, 67% of the RNIVCT embolization group vs 48% of the nonembolization group had retrohepatic (level III) or supradiaphragmatic (level IV) thrombus extension (P = .032). The RNIVCT embolization patients had a greater median number of perioperative units transfused (8 vs 4; P = .001), a longer operative time (390 vs 313 minutes; P < .001), more postoperative complications (43% vs 29%; P < .001), a longer intensive care unit stay (2 vs 0.5 days), and increased perioperative mortality (13% vs 3%; P = .017). No differences were found in intraoperative complications or length of hospitalization. Multivariate analysis showed a fivefold greater risk of perioperative death (adjusted odds ratio 5.5; P = .029) and a trend toward increased blood transfusion (regression coefficient 3.9; P = .08) with preoperative embolization. CONCLUSIONS The results of our study have shown that routine preoperative renal artery embolization in patients undergoing RNIVCT does not provide any measurable benefit in reducing blood loss or complications and was associated with increased major perioperative complications and mortality.

Differences in proteinuria and graft function in de novo sirolimus-based vs. calcineurin inhibitor-based immunosuppression in live donor kidney transplantation.

Background. Calcineurin inhibitor(CNI)-free protocols using sirolimus (SRL) in kidney transplantation have proven effective, although reports have linked SRL to proteinuria. We sought to investigate this link and its impact on graft function. Methods. We retrospectively analyzed 184 live donor kidney transplant recipients who exclusively received de novo CNI-based (n=106) or SRL-based (n=78) regimens. Estimated glomerular filtration rate (GFR) and semi-quantitative dipstick proteinuria measurements were obtained at one, six, 12, and 24 months and six and 12 months, respectively. Results. SRL-treated patients had higher frequencies of proteinuria (≥1+) at 6 months (40.8% vs. 21.4%, P=0.006) and 12 months (37.8% vs. 18.4%, P=0.004) than those treated with CNI. Independent predictors of proteinuria at 12 months were GFR at one month (OR 0.62 per 10 ml/min/1.73m2, P<0.001), delayed graft function (OR 11.5, P=0.02), and a SRL-based regimen (OR 4.18, P=0.002). By univariable analysis, SRL vs. CNI patients had higher GFR at each point. SRL-treated patients without proteinuria had higher GFR at 12 months compared to CNI-treated patients with and without proteinuria (66 vs. 50 or 56 ml/min/1.73m2, P<0.05). No difference in GFR was seen between SRL-treated patients with proteinuria vs. CNI-treated patients without proteinuria (57 vs. 56 ml/min/1.73m2, P>0.05). Absence of proteinuria and a SRL-based regimen remained independently associated FSwith higher GFR at 12 months by multivariable analyses. Conclusions. De novo SRL-based immunosuppression is associated with a higher frequency of semi-quantitative proteinuria, however, estimated graft function at 1 year posttransplant remains superior to that of CNI-treated patients. Nevertheless, the long-term implications of these findings need to be determined.

Donor factors influencing graft outcomes in live donor kidney transplantation

Living donor renal allograft survival is superior to that achieved from deceased donors, although graft outcome is suboptimal in some of these patients. In an effort to identify the subset of patients at high risk for poor outcomes we studied donor risk factors in 248 living kidney donor–recipient pairs. Unadjusted donor 125I-iothalamate GFR (iGFR), donor age more than 45 years, donor total cholesterol level less than 200 mg/dL, and donor systolic blood pressure (SBP) less than 120 mm Hg were correlated with allograft estimated glomerular filtration rate (eGFR), and incidence of acute rejection (AR), delayed graft function and/or graft loss at 2 years posttransplantation. Donor iGFR less than 110 mL/min (slope=−7.40, P<0.01), donors more than 45 years (slope=−8.76, P<0.01), donor total cholesterol levels more than 200 mg/dL (slope=−10.03, P<0.01), and SBP more than 120 mm Hg (slope=−5.60, P=0.03) were associated with lower eGFR. By multivariable linear regression analysis these variables remained independently associated with lower eGFR, and poorer outcomes. The increasing number of donor factors (age, iGFR, cholesterol, and blood pressure) was directly associated with worse posttransplant eGFR (P<0.01). In conclusion, our data suggest that routine assessment of living donor parameters could supplement the consideration of recipient characteristics in predicting posttransplant risk of graft injury/dysfunction.

Expression of IL-8 during reperfusion of renal allografts is dependent on ischemic time.

Background. Ischemia/reperfusion injury is an inherent consequence of solid organ transplantation that increases tissue inflammation and negatively impacts organ transplant function and survival. This study investigated the expression levels of chemokine and chemokine receptor genes in living versus cadaver donor renal allografts before and after reperfusion. Methods. This study involved 39 renal transplant patients (19 cadaveric and 20 living donor). The ischemia biopsy was taken just before graft declamping and the reperfusion biopsy 30 min after declamping. Whole-cell RNA was isolated and chemokine (IL-8, CCL2/MCP-1, CXCL10/IP-10 and CCL5/RANTES) and chemokine receptor (CCR2 and CCR5) expression was tested by quantitative PCR. Results. Just prior to declamping, ischemic cadaveric donor grafts had higher expression of CXCL10/IP-10 but not IL-8 or CCL2/MCP-1 than living donor grafts. IL-8 expression increased 50% from ischemia to reperfusion in living donor grafts but increased more than 13-fold during reperfusion of cadaver donor grafts. Increased total ischemia time induced greater IL-8 expression during reperfusion. MCP-1 expression also increased during reperfusion of living and cadaver donor grafts but differences were not observed between the two groups of grafts. RANTES, CCR2, and CCR5 expression did not change in ischemic vs. reperfusion biopsies. Conclusions. The expression of chemokines directing neutrophil and macrophage recruitment increases during reperfusion of living and cadaveric donor renal allografts. Expression levels of IL-8 correlate with the ischemic time imposed on the renal graft. Early tissue injury may be attenuated by strategies antagonizing chemokines directing the recruitment of neutrophils and macrophages into kidney grafts.

The Effect of Sunitinib on Primary Renal Cell Carcinoma and Facilitation of Subsequent Surgery

PURPOSE We investigated the effect of sunitinib on locally advanced primary renal carcinoma tumors and the ability to facilitate subsequent surgery. MATERIALS AND METHODS Patients with an unresectable primary renal tumor, with or without distant metastases, received 50 mg sunitinib with continuous daily dosing in a phase II trial. Computerized tomography was performed every 12 weeks to determine surgical resectability. The primary end point of the trial was the percentage of patients with renal cell carcinoma and initially unresectable primary tumors who could undergo nephrectomy after sunitinib therapy. RESULTS Of 30 patients enrolled in the study (19 with distant metastases) 28 (35 total renal tumors) were evaluable for response. The median change in primary renal cell carcinoma tumors was a 22% decrease, corresponding to a median absolute reduction of 1.2 cm. The median reduction in primary renal cell carcinoma tumors of clear cell histology was -28% (absolute reduction 1.7 cm) compared to a 1.4% increase (0.1 cm absolute increase) in nonclear cell tumors. Of these patients 13 (45%) met the primary end point of being able to undergo nephrectomy after preoperative sunitinib. All patients had viable renal cell carcinoma in the surgical specimen and surgical morbidity was consistent with prior experience of nephrectomy in patients without preoperative therapy. CONCLUSIONS Sunitinib as initial therapy in patients with locally advanced features of the primary tumor was feasible and resulted in an antitumor effect that enabled subsequent surgery in a subset of patients. Further prospective study is required to refine the most suitable application of this approach.