Hospital-acquired renal insufficiency

Despite myriad improvements in the care of hospitalized patients, a decline in renal function remains a common event. Renal function in 4,622 consecutive patients admitted to the medical and surgical services of an urban tertiary care hospital was followed up prospectively from the time of admission. Some degree of renal insufficiency developed in 7.2% of patients. Decreased renal perfusion, medications, surgery, and radiographic contrast media were the most common causes of hospital-acquired renal insufficiency (HARI). The overall mortality rate was 19.4% and was similar among patients for all causes of renal insufficiency, except sepsis. For patients with a greater than 3.0-mg/dL increase in serum creatinine level, the mortality rate was 37.8%. As shown by previous investigators, age and preexisting renal insufficiency were risk factors for HARI. Women and blacks had less hospital-acquired renal failure. The increasing acuity of hospital admissions has been accompanied by a greater incidence of acute renal insufficiency in patients admitted to hospitals. There is a trend toward better survival in patients with a severe deterioration in renal function.

Lack of improvement in renal allograft survival despite a marked decrease in acute rejection rates over the most recent era

Acute rejection is known to have a strong impact on graft survival. Many studies suggest that very low acute rejection rates can be achieved with current immunosuppressive protocols. We wanted to investigate how acute rejection rates have evolved on a national level in the U.S. and how this has impacted graft survival in the most recent era of kidney transplantation. For this purpose, we analyzed data provided by the Scientific Registry of Transplant Recipients regarding all adult first renal transplants between 1995 and 2000. We noted a significant decrease in overall acute rejection rates during the first 6 months, during the first year, and also in late rejections during the second year after transplantation. Despite this decrease in the rate of acute rejection, there was no significant improvement in overall graft survival; furthermore, we noted a statistically significant trend towards worse death-censored graft survival. There was also a trend for a greater proportion of rejection episodes to fail to recover to previous baseline function after treatment. Our data suggest that decreasing acute rejection rates between 1995 and 2000 have not led to an increase in long-term graft survival. Part of this discordance might be related to a higher proportion of acute rejections which have not resolved with full functional recovery in more recent years. However, the etiology of this concerning trend for worse death censored graft survival in recent years will warrant further investigation.

A role for CD95 ligand in preventing graft rejection

Testis is a remarkable immune-privileged site, long known for its ability to support allogeneic and xenogeneic tissue transplants. Here we have investigated the molecular basis for testis immune privilege. Testis grafts derived from mice that can express functional CD95 (Fas or Apo-1) ligand survived indefinitely when transplanted under the kidney capsule of allogeneic animals, whereas testis grafts derived from mutant gld mice, which express non-functional ligand, were rejected. Further analysis of testis showed that CD95 ligand messenger RNA is constitutively expressed by testicular Sertoli cells, and that Sertoli cells from normal mice, but not gld mice, were accepted when transplanted into allogeneic recipients. CD95 ligand expression in the testis probably acts by inducing apoptotic cell death of CD95-expressing, recipient T cells activated in response to graft antigens. These findings indicate that CD95 ligand could be used to create immune-privileged tissue for a variety of transplant uses.

A 2018 Reference Guide to the Banff Classification of Renal Allograft Pathology

The Banff Classification of Allograft Pathology is an international consensus classification for the reporting of biopsies from solid organ transplants. Since its initial conception in 1991 for renal transplants, it has undergone review every 2 years, with attendant updated publications. The rapid expansion of knowledge in the field has led to numerous revisions of the classification. The resultant dispersal of relevant content makes it difficult for novices and experienced pathologists to faithfully apply the classification in routine diagnostic work and in clinical trials. This review shall provide a complete and simple illustrated reference guide of the Banff Classification of Kidney Allograft Pathology based on all publications including the 2017 update. It is intended as a concise desktop reference for pathologists and clinicians, providing definitions, Banff Lesion Scores and Banff Diagnostic Categories. An online website reference guide hosted by the Banff Foundation for Allograft Pathology (www.banfffoundation.org) is being developed, which will be updated with future refinement of the Banff Classification from 2019 onward.

Endovascular ultrasound renal denervation to treat hypertension (RADIANCE-HTN SOLO): a multicentre, international, single-blind, randomised, sham-controlled trial

BACKGROUND

Early studies suggest that radiofrequency-based renal denervation reduces blood pressure in patients with moderate hypertension. We investigated whether an alternative technology using endovascular ultrasound renal denervation reduces ambulatory blood pressure in patients with hypertension in the absence of antihypertensive medications.

METHODS

RADIANCE-HTN SOLO was a multicentre, international, single-blind, randomised, sham-controlled trial done at 21 centres in the USA and 18 in Europe. Patients with combined systolic-diastolic hypertension aged 18-75 years were eligible if they had ambulatory blood pressure greater than or equal to 135/85 mm Hg and less than 170/105 mm Hg after a 4-week discontinuation of up to two antihypertensive medications and had suitable renal artery anatomy. Patients were randomised (1:1) to undergo renal denervation with the Paradise system (ReCor Medical, Palo Alto, CA, USA) or a sham procedure consisting of renal angiography only. The randomisation sequence was computer generated and stratified by centres with randomised blocks of four or six and permutation of treatments within each block. Patients and outcome assessors were blinded to randomisation. The primary effectiveness endpoint was the change in daytime ambulatory systolic blood pressure at 2 months in the intention-to-treat population. Patients were to remain off antihypertensive medications throughout the 2 months of follow-up unless specified blood pressure criteria were exceeded. Major adverse events included all-cause mortality, renal failure, an embolic event with end-organ damage, renal artery or other major vascular complications requiring intervention, or admission to hospital for hypertensive crisis within 30 days and new renal artery stenosis within 6 months. This study is registered with ClinicalTrials.gov, number NCT02649426.

FINDINGS

Between March 28, 2016, and Dec 28, 2017, 803 patients were screened for eligibility and 146 were randomised to undergo renal denervation (n=74) or a sham procedure (n=72). The reduction in daytime ambulatory systolic blood pressure was greater with renal denervation (-8·5 mm Hg, SD 9·3) than with the sham procedure (-2·2 mm Hg, SD 10·0; baseline-adjusted difference between groups: -6·3 mm Hg, 95% CI -9·4 to -3·1, p=0·0001). No major adverse events were reported in either group.

INTERPRETATION

Compared with a sham procedure, endovascular ultrasound renal denervation reduced ambulatory blood pressure at 2 months in patients with combined systolic-diastolic hypertension in the absence of medications.

FUNDING

ReCor Medical.

Vasculotropic, paracrine actions of infused mesenchymal stem cells are important to the recovery from acute kidney injury

Acute kidney injury (AKI) is a major clinical problem in which a critical vascular, pathophysiological component is recognized. We demonstrated previously that mesenchymal stem cells (MSC), unlike fibroblasts, are significantly renoprotective after ischemia-reperfusion injury and concluded that this renoprotection is mediated primarily by paracrine mechanisms. In this study, we investigated whether MSC possess vasculoprotective activity that may contribute, at least in part, to an improved outcome after ischemia-reperfusion AKI. MSC-conditioned medium contains VEGF, HGF, and IGF-1 and augments aortic endothelial cell (EC) growth and survival, a response not observed with fibroblast-conditioned medium. MSC and EC share vasculotropic gene expression profiles, as both form capillary tubes in vitro on Matrigel alone or in cooperation without fusion. MSC undergo differentiation into an endothelial-like cell phenotype in culture and develop into vascular structures in vivo. Infused MSC were readily detected in the kidney early after reflow but were only rarely engrafted at 1 wk post-AKI. MSC attached in the renal microvascular circulation significantly decreased apoptosis of adjacent cells. Infusion of MSC immediately after reflow in severe ischemia-reperfusion AKI did not improve renal blood flow, renovascular resistance, or outer cortical blood flow. These data demonstrate that the unique vasculotropic, paracrine actions elicited by MSC play a significant renoprotective role after AKI, further demonstrating that cell therapy has promise as a novel intervention in AKI.

Efficacy of catheter-based renal denervation in the absence of antihypertensive medications (SPYRAL HTN-OFF MED Pivotal): a multicentre, randomised, sham-controlled trial

BACKGROUND

Catheter-based renal denervation has significantly reduced blood pressure in previous studies. Following a positive pilot trial, the SPYRAL HTN-OFF MED (SPYRAL Pivotal) trial was designed to assess the efficacy of renal denervation in the absence of antihypertensive medications.

METHODS

In this international, prospective, single-blinded, sham-controlled trial, done at 44 study sites in Australia, Austria, Canada, Germany, Greece, Ireland, Japan, the UK, and the USA, hypertensive patients with office systolic blood pressure of 150 mm Hg to less than 180 mm Hg were randomly assigned 1:1 to either a renal denervation or sham procedure. The primary efficacy endpoint was baseline-adjusted change in 24-h systolic blood pressure and the secondary efficacy endpoint was baseline-adjusted change in office systolic blood pressure from baseline to 3 months after the procedure. We used a Bayesian design with an informative prior, so the primary analysis combines evidence from the pilot and Pivotal trials. The primary efficacy and safety analyses were done in the intention-to-treat population. This trial is registered at ClinicalTrials.gov, NCT02439749.

FINDINGS

From June 25, 2015, to Oct 15, 2019, 331 patients were randomly assigned to either renal denervation (n=166) or a sham procedure (n=165). The primary and secondary efficacy endpoints were met, with posterior probability of superiority more than 0·999 for both. The treatment difference between the two groups for 24-h systolic blood pressure was -3·9 mm Hg (Bayesian 95% credible interval -6·2 to -1·6) and for office systolic blood pressure the difference was -6·5 mm Hg (-9·6 to -3·5). No major device-related or procedural-related safety events occurred up to 3 months.

INTERPRETATION

SPYRAL Pivotal showed the superiority of catheter-based renal denervation compared with a sham procedure to safely lower blood pressure in the absence of antihypertensive medications.

FUNDING

Medtronic.

Radiofrequency and microwave ablation of the liver, lung, kidney, and bone: what are the differences?

Radiofrequency (RF) ablation is becoming an accepted treatment modality for many tumors of the liver and is being explored for tumors in the lung, kidney, and bone. While RF energy is the most familiar heat source for tissue ablation, it has certain limitations that may hamper its efficacy in these new organ systems. Microwave energy may be a better source for tissue ablation but has technical hurdles that must be overcome as well. This article outlines the physics behind RF and microwave heating, discusses relevant properties of the liver, lung, kidney, and bone for thermal ablation and examines the roles of RF and microwave ablation in these tissues.

Infrarenal abdominal aortic aneurysm: factors influencing survival after operation performed over a 25-year period

This report is concerned with the factors influencing survival in 920 consecutive patients submitted to operation for infrarenal abdominal aortic aneurysm during the past 25 years. Rupture had occurred in 60 patients (6.5%) and survival was 77%, which did not vary during the period of study. Of the 860 patients (93.5%) treated for nonrupture, 819 (95%) survived operation. The mortality rate in this group varied from 18%, in the earlier period to 1.43% , in recent years. Risk factors including heart disease, hypertension, and advanced age accounted for 95% of the deaths that occurred within 30 days however, the mortality rate in patients with these problems decreased from 19.2% to 1.9% during the period of study although the average number of patients treated each year with these risk factors increased tenfold. Improvements in operative techniques and experience were responsible for decreasing mortality up to about 1971. Subsequent decrease in mortality was due to improvements in anesthesia, monitoring, and other supportive measures during operation and the early recovery period. Complete survival information was obtained in 816 (99.6%) patients, 191 of whom had been treated for periods over 15 years. Factors influencing long-term survival were associated disease and age at time of operation. Survival in percentage in patients without associated heart disease of hypertension for 5, 10, and 15 years was 84, 49, and 21; with heart disease, it was 54, 34, and 17. The median age of patients in the series was 65.5 years and survival at above intervals according to quartile was less than or equal to 60; 71, 53, and 24; 60 less than age less than or equal to 71; 66, 38, and 18; less greater than 71; 43, 13, and 11.

Robotic laparoscopic surgery: a comparison of the DA Vinci and Zeus systems

OBJECTIVES

To evaluate two currently available robotic surgical systems in performing various urologic laparoscopic procedures in an acute porcine model.

METHODS

Robotic laparoscopic surgery was performed in 14 swine. Data were compared between the da Vinci Robotic System and the Zeus Robotic System.

RESULTS

During laparoscopic nephrectomy, the da Vinci System (n = 6) had a significantly shorter total operating room time (51.3 versus 71.6 minutes; P = 0.02) and actual surgical time (42.1 versus 61.4 minutes; P = 0.03) compared with the Zeus System (n = 5). However, the blood loss and adequacy of surgical dissection were comparable between the two groups. For laparoscopic adrenalectomy, the da Vinci System (n = 5) had a shorter actual surgical time (12.2 versus 26.0 minutes; P = 0.006) than did the Zeus System (n = 5). For laparoscopic pyeloplasty, the da Vinci System had a shorter total operating room time (61.4 versus 83.4 minutes; P = 0.10) and anastomotic time (44.7 versus 66.4 minutes; P = 0.11). During pyeloplasty anastomosis, the total number of suture bites per ureter was 13.0 for the da Vinci System (n = 6) and 10.8 for the Zeus System (n = 6). The complications included an adrenal parenchymal tear each during a da Vinci System-based left adrenalectomy and a Zeus System-based right adrenalectomy. An inferior vena caval tear during a Zeus System-based right adrenalectomy occurred in 1 case, which was suture-repaired telerobotically.

CONCLUSIONS

Robotic laparoscopic procedures can be performed effectively using either the da Vinci or Zeus System. In this limited study, the learning curve and operative times were shorter and the intraoperative technical movements appeared inherently more intuitive with the da Vinci System. Additional clinical experience is necessary.

Hypertension of renal origin: evidence for two different mechanisms

Antibody to angiotensin 11, or a specific peptide competitive inhibitor of angiolensin II, was used to investigate the role of the renin-angiotensin system in two types of renal hypertension in rats. The data indicate that angiotensin II is in fact critically involved in the pathogenesis of the form of renal hypertension in which one renal artery is clamped and the contralateral kidney is left in place, but that it probably plays no significant role in the maintenance of experimental renal hypertension in which the opposite kidney has been removed.

Experience with new double J ureteral catheter stent

Experience with a newly designed self-retaining silicone ureteral stent is presented. The stent is supplied in various lengths, has a J or hook molded into each end to prevent migration and has been designed specifically to be passed during an open operation as well as endoscopically. The device is used to provide free drainage to the bladder, reduce or eliminate urine leakage, provide stenting of the ureter and allow for earlier discharge from the hospital of patients without external catheters. In some cases the stent may be used instead of a nephrostomy tube to provide prolonged drainage with less chance of infection. It is removed easily in the outpatient facility by cystoscopy.

Potential role of regulatory T cells in reversing obesity-linked insulin resistance and diabetic nephropathy

OBJECTIVE

To assess the potential role of FoxP3-expressing regulatory T cells (Tregs) in reversing obesity-linked insulin resistance and diabetic nephropathy in rodent models and humans.

RESEARCH DESIGN AND METHODS

To characterize the role of Tregs in insulin resistance, human visceral adipose tissue was first evaluated for Treg infiltration and second, the db/db mouse model was evaluated.

RESULTS

Obese patients with insulin resistance displayed significantly decreased natural Tregs but an increase in adaptive Tregs in their visceral adipose tissue as compared with lean control subjects. To further evaluate the pathogenic role of Tregs in insulin resistance, the db/db mouse model was used. Treg depletion using an anti-CD25 monoclonal antibody enhanced insulin resistance as shown by increased fasting blood glucose levels as well as an impaired insulin sensitivity. Moreover, Treg-depleted db/db mice developed increased signs of diabetic nephropathy, such as albuminuria and glomerular hyperfiltration. This was paralleled by a proinflammatory milieu in both murine visceral adipose tissue and the kidney. Conversely, adoptive transfer of CD4(+)FoxP3(+) Tregs significantly improved insulin sensitivity and diabetic nephropathy. Accordingly, there was increased mRNA expression of FoxP3 as well as less abundant proinflammatory CD8(+)CD69(+) T cells in visceral adipose tissue and kidneys of Treg-treated animals.

CONCLUSIONS

Data suggest a potential therapeutic value of Tregs to improve insulin resistance and end organ damage in type 2 diabetes by limiting the proinflammatory milieu.

Management of Renal Masses and Localized Renal Cancer: Systematic Review and Meta-Analysis

PURPOSE

Several options exist for management of clinically localized renal masses suspicious for cancer, including active surveillance, thermal ablation and radical or partial nephrectomy. We summarize evidence on effectiveness and comparative effectiveness of these treatment approaches for patients with a renal mass suspicious for localized renal cell carcinoma.

MATERIALS AND METHODS

We searched MEDLINE®, Embase® and the Cochrane Central Register of Controlled Trials from January 1, 1997 through May 1, 2015. Paired investigators independently screened articles to identify controlled studies of management options or cohort studies of active surveillance, abstracted data sequentially and assessed risk of bias independently. Strength of evidence was graded by comparisons.

RESULTS

The search identified 107 studies (majority T1, no active surveillance or thermal ablation stratified outcomes of T2 tumors). Cancer specific survival was excellent among all management strategies (median 5-year survival 95%). Local recurrence-free survival was inferior for thermal ablation with 1 treatment but reached equivalence to other modalities after multiple treatments. Overall survival rates were similar among management strategies and varied with age and comorbidity. End-stage renal disease rates were low for all strategies (0.4% to 2.8%). Radical nephrectomy was associated with the largest decrease in estimated glomerular filtration rate and highest incidence of chronic kidney disease. Thermal ablation offered the most favorable perioperative outcomes. Partial nephrectomy showed the highest rates of urological complications but overall rates of minor/major complications were similar among interventions. Strength of evidence was moderate, low and insufficient for 11, 22 and 30 domains, respectively.

CONCLUSIONS

Comparative studies demonstrated similar cancer specific survival across management strategies, with some differences in renal functional outcomes, perioperative outcomes and postoperative harms that should be considered when choosing a management strategy.

Percutaneous stone manipulation

Percutaneous stone manipulation by direct ultrasound disintegration, extraction or chemolysis was done on 34 patients. A total of 15 patients presented with an operatively established nephrostomy, while percutaneous nephrostomy and subsequent dilation of the nephrostomy channel were done in 19. The rate of complete stone clearance was 19 of 20 stones after percutaneous nephrostomy and 8 of 16 stones in the group with an operatively established nephrostomy. The primary goal, to remove obstructing pelvic stones, was achieved in all cases. There were no untoward side effects, such as back pressure damage owing to flushing of the collecting system during ultrasound disintegration, or persistent infection. Complications in 3 patients were managed conservatively.

Angiomyolipoma with minimal fat: differentiation from renal cell carcinoma at biphasic helical CT

PURPOSE

To compare various computed tomographic (CT) features of angiomyolipoma (AML) with minimal fat with those of size-matched renal cell carcinoma (RCC).

MATERIALS AND METHODS

Eighty-one patients (19 with AML with minimal fat [mean diameter, 2.8 cm; range, 1.5-4.5 cm] and 62 with RCC [mean diameter, 3.1 cm; range, 1.8-4.5 cm]) who had undergone biphasic CT (ie, CT with unenhanced, corticomedullary, and early excretory phase scanning) were evaluated. Two reviewers who were unaware of the diagnosis retrospectively recorded tumor attenuation on unenhanced scans, enhancement characteristics (ie, homogeneity of enhancement, amount of enhancement, enhancement pattern over time), tumor margin, location of tumor center, intratumoral calcification, perinephric changes, and patient age and sex. The predictive value of each CT finding was determined by using multivariate logistic regression analysis.

RESULTS

Homogeneous enhancement (observed in 79% of AMLs vs 5% of RCCs; odds ratio, 37) and prolonged enhancement pattern (observed in 58% of AMLs vs 10% of RCCs; odds ratio, 42) were valuable predictors for differentiating AML with minimal fat from RCC at multivariate analysis (P <.05 for both). When both CT findings were used as a criterion for differentiating AML from RCC, positive and negative predictive values were 91% (10 of 11 tumors) and 87% (61 of 70 tumors), respectively. Fifty-three percent of AMLs versus 13% of RCCs showed high tumor attenuation on unenhanced scans (P =.04), whereas RCCs showed greater mean enhancement than AMLs (114 HU +/- 44 [SD] vs 73 HU +/- 30 in corticomedullary phase and 66 HU +/- 24 vs 49 HU +/- 20 in early excretory phase) and a male predominance (male-to-female ratio, 50:12 vs 8:11; P =.001).

CONCLUSION

Biphasic helical CT may be useful in differentiating AML with minimal fat from RCC, with homogeneous tumor enhancement and prolonged enhancement pattern being the most valuable CT findings.

The fate of allogeneic and xenogeneic neuronal tissue transplanted into the third ventricle of rodents

Neural grafts from day 17-19 fetal rats or mice survived well when transplanted into syngeneic, or immunodeficient hosts, thus demonstrating that there are no non-immunological barriers to cross-species transplantation of neuronal tissue in rats and mice. However, intraventricular grafts from rat to mouse, or vice versa, in immunocompetent animals were rejected in less than 30 days. By this time all graft tissue had been destroyed and scavenged, presumably by the macrophages seen infiltrating the grafts within 10 days of grafting. Rat allografts from major histocompatibility complex disparate donors disparate donors survived well as did grafts between rats differing only at minor histocompatibility loci. However, allografts from donors that differed from recipients at both major and minor histocompatibility complex loci had a variable survival time. When neural tissue was grafted into immunologically primed recipients, it was rejected as was similar tissue grafted beneath the kidney capsule of an allogeneic host. Concomitant grafting of allogeneic tissue under the kidney capsule and into the third ventricle was followed by rejection in both sites. A striking observation in these studies was the induction of Class I major histocompatibility complex antigens on grafted neuronal tissue. High levels of antigen expression were correlated with a vigorous host response and poor graft survival but lower levels were not indicative of impending graft destruction. Whilst the brain can be regarded as an immunologically privileged site, the privilege is not absolute and caution needs to be exercised in the interpretation of results from allogeneic or xenogeneic grafts.

Catheter-based renal denervation for resistant hypertension: rationale and design of the SYMPLICITY HTN-3 Trial

Hypertension represents a significant global public health concern, contributing to vascular and renal morbidity, cardiovascular mortality, and economic burden. The opportunity to influence clinical outcomes through hypertension management is therefore paramount. Despite adherence to multiple available medical therapies, a significant proportion of patients have persistent blood pressure elevation, a condition termed resistant hypertension. Recent recognition of the importance of the renal sympathetic and somatic nerves in modulating blood pressure and the development of a novel procedure that selectively removes these contributors to resistant hypertension represents an opportunity to provide clinically meaningful benefit across wide and varied patient populations. Early clinical evaluation with catheter-based, selective renal sympathetic denervation in patients with resistant hypertension has mechanistically correlated sympathetic efferent denervation with decreased renal norepinephrine spillover and renin activity, increased renal plasma flow, and has demonstrated clinically significant, sustained reductions in blood pressure. The SYMPLICITY HTN-3 Trial is a pivotal study designed as a prospective, randomized, masked procedure, single-blind trial evaluating the safety and effectiveness of catheter-based bilateral renal denervation for the treatment of uncontrolled hypertension despite compliance with at least 3 antihypertensive medications of different classes (at least one of which is a diuretic) at maximal tolerable doses. The primary effectiveness endpoint is measured as the change in office-based systolic blood pressure from baseline to 6 months. This manuscript describes the design and methodology of a regulatory trial of selective renal denervation for the treatment of hypertension among patients who have failed pharmacologic therapy.

Progression and survival after renal-conserving surgery for renal cell carcinoma: experience in 104 patients and extended followup

Of 104 patients who underwent a conservative operation for renal cell carcinoma 42 underwent partial nephrectomy, 60 underwent enucleation and 2 underwent a combination of these procedures. A total of 14 patients required an extracorporeal operation with autotransplantation. Forty patients had bilateral renal cell carcinoma (20 were synchronous and 20 were asynchronous) and 39 had either a solitary kidney or a poorly functioning contralateral renal unit. An operation was performed in the presence of a normal contralateral unit in 20 patients. The maximal duration of followup was 20 years (mean 4.9 years): 43, 17 and 7 patients were followed for 5 or more, 10 or more and 15 or more years, respectively. The 5-year cause-specific survival rates were 88.6 +/- 5.6, 91.6 +/- 4.7 and 88.9 +/- 3.8%, respectively, for the enucleation group, partial nephrectomy group and all patients combined. The percentages of patients free of local recurrence at 5 years for the enucleation and partial nephrectomy groups were 94.6 +/- 3.9 and 93.3 +/- 4.7%, respectively. The 14 patients who required an ex vivo approach had larger, higher stage and higher grade tumors, and a poorer outcome (5-year cause-specific survival rate and local rate free of recurrence were 54.9 +/- 17.2 and 85.7 +/- 13.2%, respectively). None of the 20 patients with a normal contralateral unit had progression. The local survival rate free of disease and cause-specific survival rate were not significantly different for the simple enucleation and partial nephrectomy groups. Even longer followup is needed to assess more clearly the definitive role of simple enucleation in the treatment of renal cell carcinoma and the clinical relevance of possible positive margins in a patient population that usually is older.

Renal cryosurgery: experimental evaluation of treatment parameters

OBJECTIVES

Cryosurgery represents a minimally invasive alternative for the management of small or equivocal lesions of the kidney. We evaluated the relationship between ultrasonographic appearance and intrarenal temperatures and the effect of renal artery occlusion on the efficacy of the freezing process in a canine model.

METHODS

Ten animals were treated with intraparenchymal cryoablative therapy with (n = 5) or without (n = 5) renal artery occlusion using a rapid freeze technique. Intrarenal temperatures were measured 1.0 cm away from the cryoprobe at various times during the freezing process. The distance from the cryoprobe to the ice ball as monitored by ultrasonography was also determined. The contralateral kidney was removed to facilitate studies of renal function and all animals were killed on day 28 for autopsy and histopathologic examination.

RESULTS

A target temperature of less than -20 degrees C was achieved 3.1 mm behind the ice ball in all animals tested. The ice ball stabilized at a radius of 16 mm with prolonged treatment, suggesting that multiple probes will be required to treat renal lesions greater than 2.5 cm in diameter. Renal artery occlusion did not significantly alter the freezing process and provided no practical advantage. Renal function remained stable (final serum creatinine level 1.5 mg/dL or less) in all but 1 animal in which an obstructive stricture of the ureteropelvic junction developed. Effective tissue ablation was confirmed at the treatment site in all instances.

CONCLUSIONS

Renal cryoablative therapy is a nephron-sparing modality that can be delivered in a safe, efficacious, and reproducible manner. The treatment parameters defined in this study should allow for intelligent patient selection and rational administration of renal cryotherapy.

Objective measures of renal mass anatomic complexity predict rates of major complications following partial nephrectomy

BACKGROUND

The association between tumor complexity and postoperative complications after partial nephrectomy (PN) has not been well characterized.

OBJECTIVE

We evaluated whether increasing renal tumor complexity, quantitated by nephrometry score (NS), is associated with increased complication rates following PN using the Clavien-Dindo classification system (CCS).

DESIGN, SETTING, AND PARTICIPANTS

We queried our prospectively maintained kidney cancer database for patients undergoing PN from 2007 to 2010 for whom NS was available.

INTERVENTIONS

All patients underwent PN.

MEASUREMENTS

Tumors were categorized into low- (NS: 4-6), moderate- (NS: 7-9), and high-complexity (NS: 10-12) lesions. Complication rates within 30 d were graded (CCS: I-5), stratified as minor (CCS: I or 2) or major (CCS: 3-5), and compared between groups.

RESULTS AND LIMITATIONS

A total of 390 patients (mean age: 58.0 ± 11.9 yr; 66.9% male) undergoing PN (44.6% open, 55.4% robotic) for low- (28%), moderate- (55.6%), and high-complexity (16.4%) tumors (mean tumor size: 3.74 ± 2.4 cm; median: 3.2 cm) from 2007 to 2010 were identified. Tumor size, estimated blood loss, and ischemia time all significantly differed (p<0.0001) between groups; patient age, body mass index (BMI), and operative time were comparable. When stratified by CCS, minor and major complication rates for all patients were 26.7% and 11.5%, respectively. Minor complication rates were comparable (26.6 vs. 24.9 vs 32.8%; p=0.45), whereas major complication rates differed (6.4 vs. 11.1 vs. 21.9%; p=0.009) among tumor complexity groups. Controlling for age, gender, BMI, type of surgical approach, operative duration, and tumor complexity, prolonged operative time (odds ratio [OR]: 1.01; confidence interval [CI], 1.0-1.02) and high tumor complexity (OR: 5.4; CI, 1.2-24.2) were associated with the postoperative development of a major complication. Lack of external validation is a limitation of this study.

CONCLUSIONS

Increasing tumor complexity is associated with the development of major complications after PN. This association should be validated externally and integrated into the decision-making process when counseling patients with complex renal tumors.