Modest serum creatinine elevation affects adverse outcome after general surgery

Cardioprotection by remote ischaemic preconditioning †

Perioperative myocardial infarction is a leading cause of morbidity and mortality after major non-cardiac surgery. Pharmacological agents such as beta-blockers may reduce the risk but are associated with side-effects and may be contra-indicated in some patients. Basic scientific experiments and preliminary clinical trials in humans suggest that remote ischaemic preconditioning (RIPC), where brief ischaemia in one tissue confers resistance to subsequent sustained ischaemic insults in another tissue, may provide a simple, cost-effective means of reducing the risk of perioperative myocardial ischaemia. The Medline and Pubmed databases were searched for articles concerning RIPC. The mechanism may be humoral, neural, or a combination of both, and involves adenosine, opioids, bradykinins, protein kinase C, and K-ATP channels, although the precise end-effector remains unclear. Small randomized trials in humans undergoing major surgery suggest that RIPC induced by brief lower limb ischaemia significantly reduces myocardial injury. It may also reduce other ischaemic complications of surgery and anaesthesia. Small studies provide some evidence that RIPC could reduce myocardial injury and other ischaemic complications of surgery. However, large-scale clinical trials to assess the effect of RIPC on mortality and morbidity are required before RIPC can be recommended for routine clinical use.

Association Between Carotid Artery Intima-Media Thickness and Early-Stage CKD in a Chinese Population

BACKGROUND

Increased carotid artery intima-media thickness (IMT) predicts future vascular events in the general population. However, the relationship between IMT and chronic kidney disease (CKD) seldom was tested in subjects with early-stage CKD.

STUDY DESIGN

Cross-sectional study.

SETTING & PARTICIPANTS

1,046 residents in 1 district of Beijing participated in the study.

OUTCOMES & MEASUREMENTS

Carotid artery IMT was measured by means of high-resolution B-mode ultrasonography. Estimated glomerular filtration rate (eGFR) was calculated using the modified Modification of Diet in Renal Disease Study equation based on data for Chinese patients with CKD. Albuminuria was evaluated by means of urinary albumin-creatinine ratio on a morning spot urine sample.

RESULTS

Compared with subjects with eGFR greater than 90 mL/min/1.73 m(2) (>1.50 mL/s/1.73 m(2)), subjects with eGFR of 60 to 89 mL/min/1.73 m(2) (1.00 to 1.49 mL/s/1.73 m(2)) and 30 to 59 mL/min/1.73 m(2) (0.50 to 0.99 mL/s/1.73 m(2)) had higher mean IMT (0.74 +/- 0.27 versus 0.82 +/- 0.30 versus 0.94 +/- 0.38 mm; P < 0.001). IMTs of subjects with albuminuria tended to be higher than the mean value (0.79 +/- 0.29 versus 0.93 +/- 0.38 mm; P < 0.001). eGFR and urinary albumin-creatinine ratio significantly correlated with IMT in univariable analysis, but not after adjusting for traditional cardiovascular disease risk factors.

LIMITATIONS

Selection bias and low prevalence of CKD might affect the strength of the study.

CONCLUSIONS

In this Chinese population older than 40 years, carotid artery IMT was significantly higher in subjects with early-stage CKD. The greater prevalence of cardiovascular disease risk factors in patients with CKD appeared to account for the higher carotid artery IMT.

Creatinine clearance but not serum creatinine alone predicts long-term postoperative survival after lower extremity revascularization

BACKGROUND

Renal insufficiency is a well-described risk factor for perioperative morbidity and shortened survival after major vascular procedures. Due to the potential inaccuracy of serum creatinine levels alone in measuring kidney function, our aim was to determine whether estimated creatinine clearance more consistently predicted long-term survival.

METHODS

A retrospective review of one institution's vascular registry was performed. Logistic regression analysis was conducted to determine independent predictors of 1-, 2- and 3-year postoperative mortality. Creatinine clearance was estimated as [140 - age (years)] x weight (kg)/72 x serum creatinine (mg/dl), multiplied by 0.85 for women.

RESULTS

A total of 252 consecutive patients underwent infrainguinal bypass procedures between August 1999 and May 2000. Demographics included average age 68 years, 65% male, 74% diabetic, 12% dialysis-dependent, 23% history of congestive heart failure, 12% history of stroke and 20% serum creatinine >2 mg/dl. One-year mortality was 16% (n = 40), 2-year mortality was 25% (n = 64), and 3-year mortality was 35% (n = 88). There was no difference in serum creatinine values between survivors and non-survivors at 1 year (1.8 vs. 1.9, p = 0.80), 2 years (1.8 vs. 2.0, p = 0.62) or 3 years (1.8 vs. 2.0, p = 0.24), and creatinine >2 mg/dl did not predict long-term adverse outcomes. In contrast, reduced creatinine clearance (< or =60 ml/min) was an independent predictor of mortality regardless of dialysis status (1 year: OR = 2.53, p = 0.014; 2 years: OR = 2.46, p = 0.004; 3 years: OR = 2.45, p = 0.001), and creatinine clearance was higher for survivors versus non-survivors at all 3 time points (1 year: 70.2 vs. 49.5, p = 0.003; 2 years: 72.3 vs. 51.2, p < 0.0001; 3 years: 74.7 vs. 52.6, p < 0.0001). Other independent predictors of mortality included a history of stroke (1 year: OR = 3.28, p = 0.008; 2 years: OR = 2.55, p = 0.025; 3 years: OR = 2.35, p = 0.038) and congestive heart failure (1 year: OR = 2.86, p = 0.006; 2 years: OR = 2.54, p = 0.005; 3 years: OR = 2.13, p = 0.017).

CONCLUSIONS

Independent of dialysis status, a decreased creatinine clearance, but not elevated serum creatinine alone, is an independent predictor of mortality after lower extremity arterial reconstruction. Determination of creatinine clearance should replace serum creatinine in the preoperative risk evaluations of patients undergoing major vascular surgical procedures.

Extensive bleeding during surgical treatment for gingival overgrowth in a patient on haemodialysis--a case report and review of the literature

Before performing renal transplantation, a most important concern is to control any infection, including oral infections before transplantation. The bleeding diathesis of patients with uraemia is a significant clinical concern, especially when surgery is required. A 44-year-old female patient on haemodialysis was referred for evaluation of gingival overgrowth. The patient was planning a renal transplantation two months later. As the lesions were not considered successfully treatable before transplantation, a gingivectomy and teeth extraction was performed. In pre-operative examinations, an abnormal bleeding time was not detected and other coagulation tests were normal. Under general anaesthesia, 19 teeth were extracted and overgrown gingiva was removed. During the operation, extensive blood loss of 1650ml occurred and four units of concentrated red blood cells were transfused. This study suggests that patients with renal failure undergoing dental surgery require careful pre-surgical evaluation including assessment of their coagulation ability.

Cardiovascular disease in early stages of chronic kidney disease in a Chinese population

Cardiovascular disease (CVD) is one of the most serious complications of kidney disease, yet studies of CVD in early stage of chronic kidney disease (CKD) in Asian patients are very limited. Therefore, this study determined the prevalence and the spectrum of CVD in individuals with early-stage CKD and compared them with data of individuals without CKD. Compared with individuals with estimated GFR (eGFR) >90 ml/min per 1.73 m2, the prevalence of myocardial infarction, stroke, and total CVD of individuals with eGFR 60 to 89 ml/min per 1.73 m2 was increased by 91.4, 71.7, and 67.6%, respectively. For individuals with eGFR 30 to 59 ml/min per 1.73 m2, the percentage was 105.2, 289.1, and 200.7%, respectively. For each eGFR category, stroke was more prevalent than myocardial infarction. Compared with individuals with eGFR >90 ml/min per 1.73 m2, participants with eGFR 60 to 89 and 30 to 59 ml/min per 1.73 m2 tended to have more cardiovascular risk factors, and there were strong unadjusted and adjusted associations between CVD with different stages of eGFR (eGFR >90 ml/min per 1.73 m2 as reference). This is the first report on the prevalence and the spectrum of CVD in early stages of CKD in a community-based Chinese population. The spectrum of CVD in this Chinese population is different from reports of Western countries. Individuals with subtle decreased renal function seem much more likely to have multiple cardiovascular risk factors and have higher prevalence of CVD than those without CKD.

Assessing the Impact of Renal Impairment on Outcome after Arterial Intervention: A Prospective Review of 1559 Patients

AIM

To investigate the impact of pre and peri-operative renal impairment on outcome, and the need for renal replacement therapy, in a multicenter study of patients undergoing a variety of surgical and radiological arterial procedures.

METHODS

A six month prospective multi-centre study of 1,559 consecutive patients undergoing arterial interventions was performed. The primary outcome measures were the development of renal impairment, 30 day mortality and the need for renal replacement therapy. CRI was defined as an admission serum Creatinine>125 micromol/l. ARI was defined as a rise in serum Creatinine of >50% above pre-operative levels, excluding patients in whom the post operative level remained <125 micromol/l. A multivariate logistic regression model was constructed to identify independent risk factors for the development of ARI and mortality.

RESULTS

There was a significantly increased 30 day mortality in those patients who developed ARI (29/90 - 32%) or who had CRI (43/269 - 16%) when compared with those whose creatinine remained normal throughout (44/1200 - 4%) (p<0.0001 - Chi-square test). One thousand two hundred and ninety patients had normal pre operative renal function and 269 patients had CRI. Seven percent (90/1290) of the patients with normal pre-operative creatinine developed ARI. Operation type, emergency presentation, and chronic renal impairment were independent predictors of both acute renal impairment (p<0.01) and mortality (p<0.001). Sixteen patients (1%) required temporary haemofiltration (in 9 patients this developed in the context of multiple organ failure) with only 1 requiring long term support. Eleven of these patients died (30 day mortality 69%).

CONCLUSIONS

Renal failure following arterial intervention is associated with significant mortality. Renal replacement therapy is necessary mainly in the setting of multiple organ failure on intensive care units with few patients surviving to require long term renal replacement therapy. The identification of the 'at risk' patient is most strongly associated with age, raised preoperative creatinine, emergency procedures and thoraco-abdominal aneurysm.

Incidence, risk factors and prognosis of changes in serum creatinine early after aortic abdominal surgery

OBJECTIVE

To determine the incidence, risk factors, and prognostic implications of serum creatinine changes following major vascular surgery.

DESIGN

Observational study.

SETTINGS

University hospital.

PATIENTS

Cohort of 599 consecutive patients undergoing elective abdominal aortic surgery.

INTERVENTIONS

Review of prospectively collected data from 1993 to 2004.

MEASUREMENTS AND RESULTS

The receiver-operator characteristic (ROC) curve analysis was used to detect the best threshold for postoperative elevation in serum creatinine (Delta Creat) in relation to major complications. A cut-off value of +0.5 mg/dl was selected to define renal dysfunction (RD(0.5) group, n=91; no RD(0.5), n=508) that was associated with higher mortality (7.7% in RD(0.5) group vs 1.4% in no RD(0.5) group, P<0.05), rate of admission to the ICU (34% vs 13%, P<0.05), and incidence of cardiovascular (9% vs 4%, P<0.05), respiratory (21% vs 7%, P<0.05), surgical (24% vs 10%, P<0.05), and septic complications (9% vs 3%, P<0.05). After multivariate analysis with logistic regression, renal dysfunction was independently related to low preoperative creatinine clearance [<40 ml/min; odds ratio (OR) 1.5, 95% confidence interval (CI) 1.1-3.9], prolonged renal ischemic time (>40 min; OR, 3.8, 95% CI, 1.9-7.2), blood transfusion (>5 units; OR, 1.9, 95% CI 1.2-6.1), and rhabdomyolysis (OR, 3.6, 95% CI 1.7-7.9).

CONCLUSIONS

Postoperative RD(0.5) (Delta Creat >0.5 mg/dl) occurs in 15% of vascular patients and carries a bad prognosis. Preoperative renal insufficiency and factors related to the complexity of surgery are the main predictors of renal dysfunction.

Occult renal impairment is common in patients with peripheral vascular disease and normal serum creatinine

OBJECTIVE

The incidence of peripheral vascular disease (PVD) and angiography/angioplasty is rising annually. The UK Small Aneurysm Trial and other trials have shown renal function is a predictor of increased mortality and failed infrainguinal bypass despite patent vessels. Renal function is classically assessed by serum creatinine (SCr). However, SCr can be normal despite significant renal impairment. A more sensitive test is creatinine clearance (CrCl) as determined by 24-hour urine collection in combination with SCr. We studied the incidence of renal impairment, as defined by CrCl, in PVD patients with normal SCr.

METHODOLOGY

All patients with PVD sufficient to necessitate angiography and normal SCr (< or =120 micromol/l - men; < or =97 micromol/l - women) had their CrCl assessed prior to angiography: using both 24-hour urine collection and the Cockcroft-Gault formula. Various blood tests, a detailed history and examination were performed. A control group of arthritic patients, age and sex-matched with similar SCr, also had their CrCl determined.

RESULTS

65 of 76 patients (86%) with normal SCr had a subnormal CrCl (<100 ml/min) and 49 (65%) had a CrCl below 60 ml/min. In the control group of arthritic patients, the proportion having impaired CrCl was significantly less - 67% below 100 mls/min (p=0.0471) and only 15% below 60 mls/min (p<0.0001). The median and interquartile range CrCl of 52 [38-81] mls/min for PVD patients was significantly worse than for control patients (80 [68-119] mls/min -p<0.0001). The Cockcroft-Gault formula for calculating CrCl did not correlate well with the urinary CrCl for the control group but did for PVD patients (p<0.0001). Factors associated with a significantly reduced CrCl were age of at least 75 years, SCr of at least 85 micromol/l and a history of coronary heart disease (all p<0.05). This had a sensitivity of 88% and specificity of 82% for identifying subnormal CrCl. Statin use was associated with a significantly improved CrCl (p=0.040).

CONCLUSION

Most PVD patients with normal serum creatinine have occult, significantly impaired renal function as defined by creatinine clearance. Vascular surgeons should include creatinine clearance in pre-operative assessment of renal function especially in patients over 75 years old, with a history of coronary heart disease or a serum creatinine over 85 micromol/l. The method of determining creatinine clearance could be the Cockcroft-Gault calculation or ideally 24-hour urinary creatinine clearance measurement. This would allow appropriate early referral to a nephrologist for further investigation and management. It is worth noting that statin use seems to be associated with a protective effect on renal function.

Defining the high-risk patient for carotid endarterectomy: An analysis of the prospective National Surgical Quality Improvement Program database

BACKGROUND

Carotid endarterectomy (CEA) is the gold standard for the treatment of carotid stenosis, but carotid angioplasty and stenting has been advocated in high-risk patients. The definition of such a population has been elusive, particularly because the data are largely retrospective. Our study examined results for CEA in the National Surgical Quality Improvement Program database (both Veterans Affairs and private sector).

METHODS

National Surgical Quality Improvement Program data were gathered prospectively for all patients undergoing primary isolated CEA during the interval 2000 to 2003 at 123 Veterans Affairs and 14 private sector academic medical centers. Study end points included the 30-day occurrence of any stroke, death, or cardiac event. A variety of clinical, demographic, and operative variables were assessed with multivariate models to identify risk factors associated with the composite (stroke, death, or cardiac event) end point. Adjudication of end points was by trained nurse reviewers (previously validated).

RESULTS

A total of 13,622 CEAs were performed during the study period; 95% were on male patients, and 91% of cases were conducted within the Veterans Affairs sector. The average age was 68.6 +/- 0.1 years, and 42.1% of the population had no prior neurologic event. The composite stroke, death, or cardiac event rate was 4.0%; the stroke/death rate was 3.4%. Multivariate correlates of the composite outcome were (odds ratio, P value) as follows: deciles of age (1.13, .018), insulin-requiring diabetes (1.73, <.001), oral agent-controlled diabetes (1.39, .003), decade of pack-years smoking (1.04, >.001), history of transient ischemic attack (1.41, >.001), history of stroke (1.51, >.001), creatinine >1.5 mg/dL (1.48, >.001), hypoalbuminemia (1.49, >.001), and fourth quartile of operative time (1.44, >.001). Cardiopulmonary comorbid features did not affect the composite outcome in this model. Regional anesthesia was used in 2437 (18%) cases, with a resultant relative risk reduction for stroke (17%), death (24%), cardiac event (33%), and the composite outcome (31%; odds ratio, 0.69; P = .008).

CONCLUSIONS

Carotid endarterectomy results across a spectrum of Veterans Affairs and private sector hospitals compare favorably to contemporary studies. These data will assist in selecting patients who are at an increased risk for adverse outcomes. Use of regional anesthetic significantly reduced perioperative complications in a risk-adjusted model, thus suggesting that it is the anesthetic of choice when CEA is performed in high-risk patients.

Minor abnormalities of renal function: a situation requiring integrated management of cardiovascular risk

Changes in renal function related with essential hypertension are associated with an elevated cardiovascular morbidity and mortality. Indices of altered renal function (e.g. microalbuminuria, increased serum creatinine concentrations, decrease in estimated creatinine clearance or overt proteinuria) are independent predictors of cardiovascular morbidity and mortality. The Framingham Heart Study documented the relevance of proteinuria for cardiovascular prognosis in the community. The Intervention as a Goal in Hypertension Treatment (INSIGHT) Study assessed the role of proteinuria as a very powerful risk factor. It has also been shown that microalbuminuria along with primary hypertension poses a high risk for cardiovascular diseases. Recent data indicate that even minor derangements of renal function are associated with the clustering of cardiovascular risk factors observed in metabolic syndrome, that promote progression of atherosclerosis. All these parameters should be routinely evaluated in clinical practice, and considered in any stratification of cardiovascular risk in hypertensive patients. The high prevalence of chronic kidney disease in the general and in the hypertensive populations implies the need for an integrative therapeutic approach to fully protect renal and cardiovascular systems simultaneously.

Chronic kidney disease as cause of cardiovascular morbidity and mortality

To make an evidence-based evaluation of the relationship between kidney failure and cardiovascular risk, we reviewed the literature obtained from a PubMed search using pre-defined keywords related to both conditions and covering 18 years (1986 until end 2003). Eighty-five publications, covering 552 258 subjects, are summarized. All but three studies support a link between kidney dysfunction and cardiovascular risk. More importantly, the association is observed very early during the evolution of renal failure: an accelerated cardiovascular risk appears at varying glomerular filtration rate (GFR) cut-off values, which were >/=60 ml/min in at least 20 studies. Many studies lacked a clear definition of cardiovascular disease and/or used a single determination of serum creatinine or GFR as an index of kidney function, which is not necessarily corresponding to well-defined chronic kidney disease. In six studies, however, chronic kidney dysfunction and cardiovascular disease were well defined and the results of these confirm the impact of kidney dysfunction. It is concluded that there is an undeniable link between kidney dysfunction and cardiovascular risk and that the presence of even subtle kidney dysfunction should be considered as one of the conditions necessitating intensive prevention of this cardiovascular risk.

An improvement in the outcome of acute renal failure

BACKGROUND

Acute renal failure (ARF) requiring hemodialysis (HD) treatment is related to high mortality. The aim of this study was to analyze the influence of age, disease severity, and catabolism intensity on ARF outcome in patients requiring HD treatment during a 15-year period (1987-2001).

METHODS

The retrospective, single-center study included 583 patients, 428 male, 155 female, age 49+/-15 years, treated by intermittent HD using cuprophane membranes with surface area of 1.3 m2. Liano's Acute Tubular Necrosis Individual Severity Score (ATNISS) score and Hypercatabolism Depuration Score (HDS) score were calculated to estimate disease severity and catabolism intensity in ARF patients.

RESULTS

Average age of patients significantly increased during the 15-year period for more than one decade (44 to 55 years; p=0.0359), especially during the last five-year period (47+/-14.5 vs. 53+/-14.7, p=0.00015). Disease severity showed significant increase comparing periods 1992-1996 and 1997-2001 (ATNISS 0.385+/-0.197 vs. 0.437+/-0.208; p=0.00137), while catabolism intensity during these periods was similar (HDS 0.569+/-0.145 vs. 0.582+/-0.127; p=0.357). Despite the older and more severely ill population of ARF patients, mortality showed a sustained decrease during the 15-year period. Mortality in the period from 1987 to 1991 (49/83; 59%) was similar with the period 1992-1996 (chi2=0.44, p=0.5081), but significantly higher than in the period 1997-2001 (114/250; 45.6%; chi2=3.98, p = 0.0471).

CONCLUSION

The results showed an improvement in the outcome of patients with ARF requiring HD treatment, despite increasing age, disease severity, and use of bioincompatible membranes.

Effect of proteinuria and glomerular filtration rate on cardiovascular risk in essential hypertension

Changes in renal function related with essential hypertension are associated with an elevated cardiovascular morbidity and mortality. Indices of altered renal function (e.g., microalbuminuria, increased serum creatinine concentrations, decrease in estimated creatinine clearance or GFR, and overt proteinuria) are independent predictors of cardiovascular morbidity and mortality. The Framingham Heart Study documented the relevance of proteinuria for cardiovascular prognosis in the community. The INSIGHT Study assessed the role of proteinuria as a risk factor in essential hypertension. The presence of proteinuria at baseline turned out to be a very potent predictor for the development of cardiovascular events and death in patients with essential hypertension and one or more associated cardiovascular risk factors. Recent data indicate that minor derangements of renal function, including proteinuria, are associated, both in the community and in the hypertensive population, with the clustering of cardiovascular risk factors observed in metabolic syndrome that promote progression of atherosclerosis. Renal function has to be routinely evaluated in every hypertensive patient, and the presence of minor alterations considered in the stratification of cardiovascular risk in hypertensive patients.

Development of chronic kidney disease in essential hypertension during long-term therapy

PURPOSE OF REVIEW

This review examines the relevance of the development of chronic kidney disease in long-term hypertensive patients on the cardiovascular prognosis.

RECENT FINDINGS

Recently published guidelines recognize the relevance of the development of chronic kidney disease in the stratification of risk for the hypertensive patient. An adequate assessment of renal function, including an estimation of the glomerular filtration rate, is mandatory in order to ensure an adequate evaluation of the global cardiovascular risk in the hypertensive patient. The presence of subtle elevations in serum creatinine concentrations is a potent predictor of a poor cardiovascular prognosis. The clustering of associated risk factors seems to justify the elevated cardiovascular risk observed in patients with essential hypertension and mild renal function derangement.

SUMMARY

Chronic kidney disease is associated with a significant increase in cardiovascular risk attributable to the simultaneous existence of other risk factors related to the metabolic syndrome. The high prevalence of chronic kidney disease in the general and hypertensive populations forces the recognition of its relevance and the need for an integrated therapeutic approach simultaneously to protect the renal and cardiovascular systems fully.

Relevancia de la insuficiencia renal en el pronóstico cardiovascular de los pacientes con hipertensión arterial esencial

Recently published guidelines recognize the relevance of the finding of chronic kidney disease in the stratification of risk of the hypertensive patient. Determination of the presence of microalbuminuria and estimation of glomerular filtration rate are mandatory in order to ensure an adequate evaluation of global cardiovascular risks in the hypertensive patient. The presence of subtle elevations of serum creatinine concentrations and/or proteinuria are also potent predictors of a poor cardiovascular prognosis. Clustering of associated risk factors seems to justify the elevated cardiovascular risk observed in patients with essential hypertension and mild alterations of renal function.

Unreferred chronic kidney disease: a longitudinal study

BACKGROUND

Chronic kidney disease (CKD) is a major health problem. A better understanding of the epidemiological characteristics of the different stages of CKD and the associated adverse outcomes is needed to establish and implement appropriate management strategies.

METHODS

A serum creatinine (SCr) level of 2.03 mg/dL or greater (> or =180 micromol/L) in men and 1.53 mg/dL or greater (> or =135 micromol/L) in women was used to identify patients with moderate to severe CKD in a predominantly Caucasian area of the United Kingdom. Patients who were unknown to renal services were identified and followed up to establish survival, rate of referral, and change in glomerular filtration rate (GFR).

RESULTS

The prevalence of CKD defined by SCr cutoff values was 5,554 per million population (pmp). Median calculated GFR of the cohort was 28.5 mL/min/1.73 m2 (range, 4.1 to 42.8 mL/min/1.73 m2), and median age was 83 years (range, 18 to 103 years). A total of 84.8% of patients were unknown to renal services. During a mean follow-up of 31.3 months, 8.1% of patients were referred. Median survival of the unreferred population was 28.1 months. Cardiovascular disease, cancer, and infection were the most common causes of death. Male sex, low GFR, and nonreferral were associated with poor outcome. The majority of unreferred patients had stable renal function. The incidence of new unreferred CKD during the first year of follow-up was 2,435 pmp, such that the prevalence remained stable at 4,910 pmp. Significant anemia (hemoglobin < 11 g/dL [<110 g/L]) was seen in 27.5% of the unreferred cohort.

CONCLUSION

Referral of all patients with CKD is unrealistic and inappropriate. Management strategies aimed at improving adverse outcomes need to take account of this and be developed and implemented through collaboration between primary care and secondary care.

Influence of renal insufficiency on limb loss and mortality after initial lower extremity surgical revascularization

OBJECTIVE

Limb loss after lower extremity surgical revascularization occurs relatively frequently in patients receiving dialysis. The goal of the present study was to determine whether patients with milder degrees of renal insufficiency are also at risk for this complication.

MATERIAL AND METHODS

This cohort study was carried out at the Department of Veterans Affairs (VA). The study sample consisted of 9932 patients undergoing an initial surgical revascularization procedure between October 1, 1995, and September 30, 2000, recorded by the VA National Surgical Quality Improvement Program (NSQIP). We examined the occurrence of major amputation within 1 year of lower extremity surgical revascularization by level of renal function.

RESULTS

Eleven percent of study patients underwent major lower extremity amputation within 1 year of NSQIP-documented lower extremity revascularization surgery: 10% (739 of 7335) of patients with normal renal function, 11% (251 of 2210) of patients with moderately reduced renal function, 12% (24 of 205) of patients with severe renal insufficiency, and 29% (53 of 182) of patients receiving dialysis. After adjustment for demographic characteristics and comorbid conditions, only patients receiving dialysis were at significantly increased risk for amputation, compared with patients with normal renal function (odds ratio, 2.46; 95% confidence interval, 1.74-3.47; P<.001). Compared with all other veterans undergoing bypass procedures, patients receiving dialysis were more likely to have a wound infection; a diagnostic code for lower extremity gangrene, infection, or ischemic ulceration; an elevated white blood cell count; and preoperative sepsis at the time of initial revascularization. In addition, they were more likely to have a preoperative hospital stay longer than 1 week, undergo concurrent minor amputation, and undergo an outflow (vs inflow) procedure.

CONCLUSION

Only patients receiving dialysis, and not patients with milder degrees of renal insufficiency, appear to be at higher risk for limb loss after revascularization, compared with patients with normal renal function. Further studies are needed to determine why patients receiving dialysis are at a singularly increased risk for limb loss after lower extremity revascularization and whether their more frequent presentation with limb-threatening infection at the time of revascularization reflects late presentation for surgery or a more rapid course of peripheral arterial disease in this patient group.

Perioperative management of patients with chronic kidney disease or ESRD

The perioperative management of patients with chronic kidney disease (CKD) or dialysis-dependent end-stage renal disease (ESRD) is complicated by both the underlying renal dysfunction, with associated disturbances of fluid and electrolyte homeostasis and altered drug clearance, and the presence of associated co-morbid conditions, including diabetes mellitus, chronic hypertension and cardiovascular and cerebrovascular disease. The impact of CKD on fluid and electrolyte management, haematological and cardiovascular complications and drug management in the perioperative period are reviewed. Special issues related to the management of haemodialysis and peritoneal dialysis patients in the perioperative period are also reviewed.

Impact of renal insufficiency on short-term morbidity and mortality after lower extremity revascularization: data from the Department of Veterans Affairs' National Surgical Quality Improvement Program

Few data are available on the impact of renal insufficiency on short-term operative outcomes after lower extremity surgical revascularization. We used prospectively collected data from the Department of Veterans Affairs' National Surgical Quality Improvement Program (NSQIP) to explore the association with renal dysfunction of adverse outcomes occurring within 30 d of lower extremity surgical revascularization in a cohort of all patients undergoing at least one lower extremity surgical revascularization from 1/1/94 to 9/30/01 (n = 18,217). Even moderate renal insufficiency (estimated GFR 30-59cc/min/1.73m(2)) was associated with an increased incidence of postoperative death (adjusted odds ratio (OR) 1.44, 95% confidence interval (CI), 1.17 to 1.77, P = 0.001), cardiac arrest (OR 1.43, CI 1.09 to 1.88, P = 0.011), myocardial infarction (OR 1.68, 1.39 to 2.16, P < 0.001), unplanned intubation (OR 1.69, CI 1.39 to 2.07, P < 0.001) and prolonged intubation (OR 1.57, CI 1.28 to 1.94, P < 0.001) within 30 d of lower extremity revascularization. However, the incidence of wound infection and graft failure requiring return to the operating room did not appear to be substantially higher in this group. Our data also show that patients with renal insufficiency undergoing revascularization were more likely to require distal procedures and to present with limb-threatening infection compared to those with normal renal function. Efforts to improve pre-and post-operative care in patients with renal insufficiency undergoing lower extremity revascularization should take into account the increased incidence of postoperative death and cardiopulmonary complications in this group in addition to more traditional concerns about operative site complications. Further studies are needed to explore reasons for the higher rate of limb-threatening infection in patients with renal insufficiency undergoing revascularization.