Influence of prophylactic use of pentoxifylline on postoperative organ function in elderly cardiac surgery patients

A Process for the Design and Development of Novel Bone Morphogenetic Protein-7 (BMP-7) Mimetics With an Example: THR-184

Growth Factors have been evaluated as therapeutic targets for the treatment of a broad spectrum of diseases. Because they are proteins with pleiotropic effects, the quest to harness their beneficial effects has presented challenges. Most Growth Factors operate at the extracellular-receptor level and have natural feedback mechanisms that modulate their effects. As proteins, they are difficult and expensive to manufacture. Frequently proteins must be administered parenterally, may invoke an immune response, and may be neutralized by naturally occurring inhibitors. To circumvent these limitations, we have undertaken an effort to develop mimetics for the Bone Morphogenetic Protein (BMP) signaling pathway effects that incorporate the beneficial effects, eliminate the deleterious effects, and thereby create effective drug-like compounds.To this end, we have designed and tested a family of small peptide BMP mimetics. The design used the three-dimensional structure of BMP-7 to identify likely active surface regions. Lead sequences were then optimized based on in vitro assays that examine the selective binding to BMP receptors, demonstrate the phosphorylation of Smad-1,5,8, detect anti-apoptosis and anti-inflammation, and block the epithelial to mesenchymal transition (EMT) in renal tubular epithelial cells. These sequences were further optimized using in vivo assays of the attenuation of acute kidney injury in a rat-model of unilateral clamp ischemic reperfusion. This process uses a Structure Variance Analysis algorithm (SVA) to identify structure/activity relationships. One member of this family, THR-184, is an agonist of BMP signaling and a potent antagonist of TGFβ signaling. This small peptide mimetic inhibits inflammation, apoptosis, fibrosis and reverses epithelial to mesenchymal transition (EMT) by regulating multiple signaling pathways involved in the cellular injury of multiple organs. Its effects have been shown to control Acute Kidney Injury (AKI). THR-184 has progressed through phase I and II clinical trials for the prevention of Cardio-Vascular Surgery (CVS) associated AKI. This work provides a roadmap for the development of other growth factor mimetics and demonstrates how we might harness their therapeutic potential.

Treatment of Patients with Cardiac Surgery Associated-Acute Kidney Injury

Members of the Acute Dialysis Quality Initiative (ADQI) participated in a 3-day conference in Vicenza in May 2007 to evaluate the available literature on this topic and draft consensus recommendations for research studies in this area. This report summarizes the available evidence and describes the key questions that will need to be addressed with the goal of standardizing the care of patients with cardiac surgery-associated acute kidney injury (CSA-AKI) and improving outcomes.

Pentoxifylline for vascular health: a brief review of the literature

Pentoxifylline is a methylxanthine derivative that has been used for several decades in the symptomatic management of intermittent claudication. For reasons that remain fairly obscure, this drug benefits blood rheology in a number of complementary ways: decreasing blood and plasma viscosity, lowering plasma fibrinogen while promoting fibrinolysis, and improving blood filterability by enhancing erythrocyte distensibility and lessening neutrophil activation. Anti-inflammatory effects on neutrophils and macrophage/monocytes—some of them attributable to pentoxifylline metabolites—appear to play a mediating role in this regard. Although clinical trials with pentoxifylline have often been too small in size to reach statistically significant findings regarding impacts on hard end points, a review of the existing literature suggests that pentoxifylline may have potential for slowing the progression of atherosclerosis, stabilising plaque, reducing risk for vascular events, improving the outcome of vascular events, dampening the systemic inflammatory response following cardiopulmonary bypass, providing symptomatic benefit in angina and intermittent claudication, enhancing cerebral blood flow in patients with cerebrovascular disease while slowing progression of vascular dementia, improving prognosis in congestive heart failure, and aiding diabetes control. This safe and usually well-tolerated drug works in ways quite distinct from other drugs more commonly used for cardiovascular protection, and hence may confer complementary benefit when used in conjunction with them. Major clinical trials of adequate statistical power are now needed to confirm the scope of benefits that pentoxifylline can confer; studies evaluating hard end points in acute coronary syndrome, stroke/transient ischaemic attack and systolic heart failure might be particularly valuable.

Preoperative oral pentoxifylline in case of coronary artery bypass grafting with left ventricular dysfunction (ejection fraction equal to/less than 30%)

OBJECTIVE

Most coronary artery bypass grafts are done by applying cardiopulmonary bypass, which usually induces unwanted inflammatory reactions and impairs the outcomes. In order to minimize the perilous response of cardiopulmonary bypass, pentoxifylline was getting used orally.

METHODS

In a prospective, placebo-controlled, randomized clinical trial, 178 coronary artery bypass graft candidates with ejection fraction lower/equal to 30%, divided into two equal groups (pentoxifylline and control), participated in the study. Pentoxifylline patients received 400 mg pentoxifylline 3 times a day for 3 days before operation. The outcomes were compared between groups using student's t-test, Mann-Whitney U-test, Pearson chi-square, or Fisher's exact test.

RESULTS

Pentoxifylline administration did not significantly affect troponin-T (p=0.68), but it reduced tumor necrosis factor-α (p=0.01) and interleukin-6 (p=0.01). It improved left ventricular ejection fraction significantly (p=0.01). White blood cell and platelet counts, hemoglobin, and hematocrit were not influenced by pentoxifylline. The drug did not affect blood urea nitrogen and creatinine, occurrence of renal failure, cerebrovascular accidents, and in-hospital mortality rate. The need for an intra-aortic balloon pump, cardiopulmonary bypass, and aortic cross-clamp times were not affected, either. Pentoxifylline decreased the intensive care unit stay (p<0.001), ventilation time, 10.4 hours in the pentoxifylline group against 14.7 hours in the control group (p=0.01), and the requirement of inotropic agents (p=0.02) and blood transfusion (p=0.01).

CONCLUSION

Pentoxifylline has more beneficial potencies in reducing adverse events after coronary artery bypass graft using cardiopulmonary bypass, than what are known.

A patient with AKI after cardiac surgery

Up to 30% of patients undergoing cardiac surgery develop AKI, with 1% requiring RRT. AKI is an independent risk factor for morbidity and mortality. Postoperatively, even minimal changes in serum creatinine are associated with a substantial increase in mortality. No intervention has been definitely proven effective in reducing kidney injury. The successful prevention and management of AKI involves identifying patients at risk for AKI, recognizing subtle abnormalities in a timely manner, performing basic clinical assessments, and responding appropriately to data obtained. With that in mind, in this Attending Rounds, a woman with AKI in the setting of cardiac surgery is presented to highlight the use of history, physical exam, hemodynamic monitoring, laboratory data trends, and urine indices in establishing the correct diagnosis and appropriate management.

Acute kidney injury after cardiovascular surgery: an overview

Acute kidney injury is a complication of open-heart surgery that carries a poor prognosis. Studies have shown that postoperative renal function deterioration in cardiovascular surgery patients increases in-hospital mortality and adversely affects long-term survival. Identifying individuals at risk for developing AKI and aggressive early intervention is extremely important to optimize outcomes. This paper provides an overview of the etiology, prognostic markers, risk factors, and prevention of AKI and treatments that may favorably affect outcomes.

Effect of pentoxifylline on preventing acute kidney injury after cardiac surgery by measuring urinary neutrophil gelatinase - associated lipocalin

Background

Based on Acute Kidney Injury Network (AKIN) criteria, we considered acute kidney injury (AKI) as an absolute increase in the serum creatinine (sCr) level of more than or equal to 0.3 mg/dl or 50%. The introduction of Urinary neutrophil gelatinase-associated lipocalin (UNGAL) has conferred earlier diagnosis of AKI. Pentoxifylline (PTX), a non-specific phosphodiesterase inhibitor, can suppress the production of some factors of inflammatory response and presumably prevent AKI. We examined the PTX on the development of AKI in cardiac surgery patients by measuring the levels of UNGAL.

Materials and methods

We performed a double blind randomized clinical trial, enrolling 28 consecutive patients undergoing elective coronary artery bypass graft (CABG) surgery. Patients were divided into two groups, one to receive PTX 5 mg/kg intravenous bolus injection, followed by 1.5 mg/kg/h continuous intravenous infusion until 3 hours after cessation of CPB and the other group received placebo. UNGAL was measured before, 3 and 24 hours after surgery. In addition serum creatinine was measured before and 24, 48, 72 and 96 hours after surgery and C-reactive protein (CRP) only 24 hours postoperatively.

Results

Both groups did not differ in demographic and baseline characteristics. 12 patients developed AKI 48 hours after surgery; 5 of them were in the intervention group and 7 in the control group (p= 0.445). There was an increase of UNGAL in both groups postoperatively, although not significant. Mean sCr was significantly increased in the control group at 24 and 48 hours after surgery (24-h mean: 0.79 ± 0.18 mg/dl vs. 1.03 ± 0.43 mg/dl, P value = 0.02; 48-h mean: 1.17 ± 0.24 mg/dl vs. 0.98 ± 0.20 mg/dl, P value = 0.03, respectively). PTX had a positive effect in preventing AKI reflecting in changes in sCr, and the increase of UNGAL was consistent with the emergence of AKI (Pearson's correlation = 0.30).

Conclusion

Our study demonstrates a weak correlation between UNGAL and sCr after cardiac surgery. The rise of UNGAL in these patients may be reduced by administration of PTX although we did not show significance. PTX could reduce the occurrence of AKI as determined by attenuation of sCr rise without causing hemodynamic instability or increased bleeding. Overall, we suggest future studies with larger sample sizes to elucidate this effect and determine the different aspects of administrating PTX.

Trial Registration

ISRCTN: IRCT138807302622N1

Novel aspects of pharmacological therapies for acute renal failure

Acute renal failure (ARF) comprises several syndromes that are associated with a sudden decrease in renal function. ARF is common among critically ill patients, is typically multifactorial and is of great prognostic significance. Indeed, even moderate changes in renal function significantly add to the morbidity and worsen mortality associated with ARF. Recent definitions, namely the renal Risk, Injury, Failure, Loss of renal function and End-stage kidney disease (RIFLE) classification or Acute Kidney Injury Network (AKIN) criteria, which incorporate the levels of oliguria in addition to fractional serum creatinine elevation, are important because the magnitude of kidney injury according to those definitions correlates very well with both short- and long-term patient survival. However, preventive strategies are most effective when started before oliguria or elevated serum creatinine is detectable, as those criteria already reflect established renal tubular cell injury. New biomarkers, including neutrophil gelatinase-associated lipocalin (NGAL), liver-type fatty acid binding protein (L-FABP) or kidney injury molecule-1 (KIM-1) that increase prior to the serum creatinine elevation are promising and have been proven to be useful in this regard in a few clinical trials. In addition, genetic profiling may define patients at risk earlier and help to individualize preventive strategies. Well established strategies include limiting dehydration and hypotension by the use of intravenous isotonic fluids at an optimal and individualized rate, as well as avoiding exposure to nephrotoxins, which include aminoglycosides, amphotericin or non-ionic contrast. Generally accepted and evidence-based pharmacological preventive or therapeutic options have not yet been established, although many drugs (e.g. renal vasodilators, diuretics and HMG-CoA reductase inhibitors [statins]) have been tested. New promising agents interfere with the apoptotic signalling that can occur in the setting of toxin exposure or ischaemia-reperfusion injury, limit inflammatory responses or modulate endothelial cell activation. In the future, these new approaches will enable us to extend our therapeutic repertoire.

Prevention of acute kidney injury and protection of renal function in the intensive care unit. Expert opinion of the Working Group for Nephrology, ESICM

BACKGROUND

Acute renal failure on the intensive care unit is associated with significant mortality and morbidity.

OBJECTIVES

To determine recommendations for the prevention of acute kidney injury (AKI), focusing on the role of potential preventative maneuvers including volume expansion, diuretics, use of inotropes, vasopressors/vasodilators, hormonal interventions, nutrition, and extracorporeal techniques.

METHOD

A systematic search of the literature was performed for studies using these potential protective agents in adult patients at risk for acute renal failure/kidney injury between 1966 and 2009. The following clinical conditions were considered: major surgery, critical illness, sepsis, shock, and use of potentially nephrotoxic drugs and radiocontrast media. Where possible the following endpoints were extracted: creatinine clearance, glomerular filtration rate, increase in serum creatinine, urine output, and markers of tubular injury. Clinical endpoints included the need for renal replacement therapy, length of stay, and mortality. Studies are graded according to the international Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) group system.

CONCLUSIONS AND RECOMMENDATIONS

Several measures are recommended, though none carries grade 1A. We recommend prompt resuscitation of the circulation with special attention to providing adequate hydration whilst avoiding high-molecular-weight hydroxy-ethyl starch (HES) preparations, maintaining adequate blood pressure using vasopressors in vasodilatory shock. We suggest specific vasodilators [corrected] under strict hemodynamic control, sodium bicarbonate for emergency procedures administering contrast media, and periprocedural hemofiltration in severe chronic renal insufficiency undergoing coronary intervention.

ELECTRONIC SUPPLEMENTARY MATERIAL

The online version of this article (doi:10.1007/s00134-009-1678-y) contains supplementary material, which is available to authorized users.

[Anti-inflammatory effects of pentoxifylline: importance in cardiac surgery]

Initially introduced as a rheologic agent for use in intermittent claudication due to peripheral artery disease and in ischemic cerebrovascular disease, the methylxanthine derivative pentoxifylline (PTX) has been shown to possess several anti-inflammatory properties which make this drug an interesting immunomodulating adjunct for the management of patients undergoing cardiac surgery. As an unspecific phosphodiesterase inhibitor PTX ameliorates the inflammatory response following a septic stimulus and blunts organ dysfunction after ischemia-reperfusion injury. Apart from this several small clinical studies have shown that the use of PTX may blunt the inflammatory response induced by cardiac surgery using a cardiopulmonary bypass. Additionally it has been shown that the perioperative application of this drug may improve postoperative function of organs at risk, such as the kidneys and liver.

Acute kidney injury and chronic kidney disease after cardiac surgery

Kidney dysfunction is common after cardiac surgery and predicts mortality risk and poorer long-term outcome, particularly when acute injury superimposes upon chronic kidney disease. Numerous insults contribute to perioperative renal impairment including major surgical trespass, procedure-specific interventions (eg, deep hypothermic circulatory arrest), and postoperative complications. Regardless of cause, evidence supports a role for renal impairment and accumulation of "uremic toxins" as direct contributors to adverse outcome. No one has yet characterized a loss of renal function small enough to be insignificant. Despite considerable research focus, progress in development of interventions aimed at perioperative renoprotection has been disappointing. However, practice modifications can influence the likelihood of acute kidney injury, and several recent advances provide hope for the future. We review pathophysiologic understanding of this disorder; evaluate the confusing relationship (causal v epiphenomena) among acute kidney injury, chronic kidney disease, and adverse outcome after cardiac surgery; and provide an evidence-based assessment of the conduct of cardiac surgery and renoprotection strategies.

Cardiac surgery as a cause of acute kidney injury: pathogenesis and potential therapies

Cardiopulmonary bypass surgery occurs in nearly 1 million patients per year. Acute kidney injury requiring dialysis can occur in up to 1% of these patients. The development of acute kidney injury is associated with substantial morbidity and mortality independent of all other factors, and many patients are left dependent on dialysis therapies. The pathogenesis of acute kidney injury involves multiple pathways. Hemodynamic, inflammatory, and nephrotoxic factors are involved and overlap each other in leading to kidney injury. Clinical studies have identified risk factors for acute kidney injury that can be used to effectively determine the risk of acute kidney injury in patients undergoing bypass surgery. These high-risk patients can then be targeted for renal protective strategies. Thus far, no single strategy has conclusively demonstrated its ability to prevent renal injury post-bypass surgery. Novel anti-inflammatory agents are in development and offer hope as potential therapies.

Pentoxifylline reduces pro-inflammatory and increases anti-inflammatory activity in patients with coronary artery disease—A randomized placebo-controlled study

The balance between different immunological stimuli is essential in the progression and stabilization of atherosclerotic plaques. Immune regulation has been suggested as potential target for the treatment of atherosclerotic disease. We sought to determine whether treatment with pentoxifylline, a phosphodiesterase inhibitor with immunomodulating properties, could reduce the pro-inflammatory response observed in patients with acute coronary syndromes (ACS) and increase anti-inflammatory activity. In a double-blind, prospective, placebo-controlled study, 64 patients with ACS were randomized to receive pentoxifylline 400mg TID or placebo for 6 months. Analysis of the pro-inflammatory markers, C-reactive protein (CRP), interleukin (IL)-6, IL-12, interferon-gamma and tumor necrosis factor (TNF)-alpha and the anti-inflammatory cytokines, transforming growth factor (TGF)-beta1 and IL-10 were done at baseline, 1 and 6 months. Pentoxifylline treatment significantly reduced the adjusted levels of CRP and TNF-alpha compared to placebo after 6 months (P=0.04 and P<0.01, respectively). IL-12 increase was significantly less pronounced with pentoxifylline (P=0.04). The levels of the anti-inflammatory cytokine, IL-10, also declined significantly less in the pentoxifylline group compared to placebo (P<0.01) with a trend towards a higher increase of TGF-beta1 in the former group (P=0.16). Pentoxifylline reduces pro-inflammatory and increases anti-inflammatory response in patients with ACS and may have beneficial clinical effects on cardiovascular events.

A randomized controlled trial of pentoxifylline for the prevention of post-ERCP pancreatitis

BACKGROUND

Pentoxifylline can ameliorate pancreatitis in animal models because of its anti-tumor necrosis factor properties.

OBJECTIVE

Our purpose was to study the safety and efficacy of pentoxifylline in the prevention of post-ERCP pancreatitis.

DESIGN

Patients due to undergo ERCP for various indications were randomized to receive pentoxifylline 400 mg orally 3 times, beginning the day before ERCP (2 and 10 pm) until the night after the procedure (6 am and 2 and 10 pm) or to receive no preventive medication. Serum amylase values were determined before and 6 and 24 hours after ERCP. Diagnosis and grading of the severity of complications was performed according to consensus criteria.

PATIENTS

One hundred fifty-eight patients received pentoxifylline (group A) and 162 had no medication (group B). The groups were similar in distributions of sex, biliary sphincterotomy, pancreatography, pancreatic duct cannulations, stone extraction, stent placement, and presence of periampullary diverticulum. Group A patients were younger (mean age 63 vs 68 years, P<.05) and biliary colic was a more frequent indication (30 vs 12, P<.05).

RESULTS

Nine (5.6%) patients in group A and 5 (3%) in group B had pancreatitis (2 and 1 severe, respectively; P=.28). Serum amylase values were similar in baseline and 6- and 24-hour samples. Two (1.2%) patients in group A and 7 (4.3%) in group B had hemorrhage.

LIMITATIONS

This was not a double-blind trial.

CONCLUSIONS

In this study pentoxifylline did not protect against post-ERCP pancreatitis or hyperamylasemia.

Modulation of systemic inflammatory response after cardiac surgery

Cardiac surgery and cardiopulmonary bypass initiate a systemic inflammatory response largely determined by blood contact with foreign surfaces and the activation of complement. It is generally accepted that cardiopulmonary bypass initiates a whole-body inflammatory reaction. The magnitude of this inflammatory reaction varies, but the persistence of any degree of inflammation may be considered potentially harmful to the cardiac patient. The development of strategies to control the inflammatory response following cardiac surgery is currently the focus of considerable research efforts. Diverse techniques including maintenance of hemodynamic stability, minimization of exposure to cardiopulmonary bypass circuitry, and pharmacologic and immunomodulatory agents have been examined in clinical studies. This article briefly reviews the current concepts of the systemic inflammatory response following cardiac surgery, and the various therapeutic strategies being used to modulate this response.

Renal failure secondary to acute tubular necrosis: epidemiology, diagnosis, and management

Acute tubular necrosis (ATN) is a form of acute renal failure (ARF) that is common in hospitalized patients. In critical care units, it accounts for about 76% of cases of ARF. Despite the introduction of hemodialysis > 30 years ago, the mortality rates from ATN in hospitalized and ICU patients are about 37.1% and 78.6%, respectively. The purpose of this review is to discuss briefly the cause, diagnosis, and epidemiology of ARF, and to review in depth the clinical trials performed to date that have examined the influence of growth factors, hormones, antioxidants, diuretics, and dialysis. In particular, the role of the dialysis modality, dialyzer characteristics, and dosing strategies are discussed.

Acute kidney injury associated with cardiac surgery

Acute renal failure (ARF) occurs in up to 30% of patients who undergo cardiac surgery, with dialysis being required in approximately 1% of all patients. The development of ARF is associated with substantial morbidity and mortality independent of all other factors. The pathogenesis of ARF involves multiple pathways. Hemodynamic, inflammatory, and nephrotoxic factors are involved and overlap each other in leading to kidney injury. Clinical studies have identified risk factors for ARF that can be used to determine effectively the risk for ARF in patients who undergo bypass surgery. These high-risk patients then can be targeted for renal protective strategies. Thus far, no single strategy has demonstrated conclusively its ability to prevent renal injury after bypass surgery. Several compounds such as atrial natriuretic peptide and N-acetylcysteine have shown promise, but large-scale trials are needed.

Nonspecific phosphodiesterase inhibition attenuates liver injury in acute endotoxemia

BACKGROUND

Endotoxemia is accompanied by pro-inflammatory cytokine production, generation of reactive oxygen species, and end-organ injury. Pentoxifylline (PTX), a methylxanthine derivative and phosphodiesterase inhibitor, is known for its anti-inflammatory properties, including down-regulation of interleukin (IL)-6 and tumor necrosis factor (TNF)-alpha synthesis. Its effects on liver function and hepatic histology following acute endotoxemia have not been investigated fully. We hypothesized that PTX would preserve liver architecture and function after intravenous lipopolysaccharide (LPS) injection.

METHODS

Anesthetized Sprague-Dawley rats received an i.v. bolus injection of LPS (5 mg/kg), LPS + PTX (25 mg/kg), or saline (sham). Plasma concentrations of alanine aminotransferase (ALT), aspartate aminotransferase (AST), TNF-alpha, IL-6, and nitrite were measured at different time points after LPS injection. Liver injury was graded according to a scoring system in a blinded fashion from 0 (normal) to 4 (severe) for hepatocellular necrosis, hemorrhage, and parenchymal and sinusoidal inflammatory infiltrates. Neutrophil infiltration was measured by counting myeloperoxidase (MPO)-positive stained cells. Nuclear factor (NF)-kappaB p-65 was measured by counting positive stained nuclei of hepatocytes and Kupffer cells (KC). Inducible nitric oxide synthase (iNOS) was evaluated by positively stained KC. Data are presented as mean +/- SEM. Analysis of variance with p < 0.05 was considered statistically significant.

RESULTS

Animals treated with PTX showed a significant reduction in liver injury score and neutrophil infiltration. Treatment with PTX significantly decreased TNF-alpha, IL-6, and the concentrations of AST and ALT when compared to LPS alone. In addition, a significant decrease in NF-kappaB-positive staining in hepatocytes and KC, as well as in KC iNOS immunostaining was observed in PTX-treated animals compared to the LPS group.

CONCLUSIONS

Pentoxifylline downregulates the inflammatory response significantly and decreases liver injury in acute endotoxemia.

The prophylactic use of the beta-blocker esmolol in combination with phosphodiesterase III inhibitor enoximone in elderly cardiac surgery patients

We assessed the influence of the prophylactic use of a combination of the IV beta-adrenergic blocker, esmolol, and the phosphodiesterase III inhibitor, enoximone, on postbypass hemodynamic status, inflammation, and endothelial and organ function in a prospective, randomized, placebo-controlled study in 42 patients aged >65 yr undergoing aortocoronary bypass grafting. In 21 patients, esmolol (aim: heart rate <70 bpm) plus enoximone (initial bolus of 0.5 mg/kg followed by a continuous infusion of 2.5 microg x kg(-1) x min(-1)) was started after induction of anesthesia and continued until the morning of the first postoperative day; another 21 patients received saline solution as placebo. Hemodynamics, splanchnic perfusion (gastric-arterial CO(2) gap), liver function (glutathione transferase-alpha plasma levels), renal function (creatinine clearance, urine concentrations of N-acetyl-beta-D-glucosaminidase), myocardial ischemia (creatine-kinase MB and troponin T plasma levels), inflammation (elastase, interleukin-6 and -8 plasma levels), and endothelial integrity (adhesion molecules plasma levels) were assessed at baseline, before and after cardiopulmonary bypass (CPB), and in the intensive care unit until the first postoperative day. Catecholamine requirements were significantly less in the treated than in the nontreated patients. Heart rate was significantly slower, cardiac index was higher, and gastric-arterial CO(2) gap was significantly lower in the treatment group. Troponin T, beta-N-acetyl-beta-D-glucosaminidase, glutathione transferase-alpha, and soluble adhesion molecules increased significantly in the untreated control, but remained almost normal in the esmolol+enoximone patients. Inflammatory responses (elastase/interleukins) were attenuated by esmolol+enoximone. We conclude that, in comparison to an untreated control, the prophylactic use of a combination of esmolol and enoximone in elderly patients undergoing cardiac surgery with cardiopulmonary bypass resulted in overall beneficial effects on postbypass hemodynamic status, organ function, inflammatory response, and endothelial integrity.

Prevention of perioperative acute renal failure: what works?

Perioperative acute renal failure (ARF) is associated with increased morbidity and mortality. Patients undergoing cardiac, vascular and major abdominal surgery and those with pre-operative renal insufficiency are at increased risk for developing post-operative ARF. The aetiologies of perioperative ARF are multi-factorial. However, pre-renal azotaemia and ischaemic acute tubular necrosis (ATN) are the predominant causes. Preventive strategies involve identifying patients at risk, optimizing intravascular volume as well as renal function with perioperative haemodynamic monitoring, and avoiding nephrotoxins. Various pharmacological agents have been used to optimize renal perfusion and tubular function. Unfortunately, none has been shown to be effective in randomized placebo-controlled trials. In this chapter, we discuss the prophylactic use of fluids, vasoactive drugs, diuretics and other agents, as well as modification of surgical techniques to reduce the incidence of perioperative ARF.

Cardiac and thoracic vascular surgery

The number of aged individuals is growing, and consequently the demands on resources for cardiac surgery will increase in the elderly. Even in the absence of obvious coexisting diseases, advanced age is always accompanied by a general decline in organ functions, and specifically by changes in structure and function of the heart and vasculature that will ultimately affect cardiovascular performance (e.g. hypertension, ischaemic heart disease, etc.). These alterations have to be taken into account when older patients require anaesthesia for cardiac surgery. Pre-operative examination must be performed carefully to estimate cardiac function as well as dysfunction of other organ systems. Benzodiazepines as well as alpha2-adrenoceptor agonists can be used for pre-medication; induction and maintenance of anaesthesia can be performed as balanced anaesthesia or total intravenous anaesthesia. Essential monitoring should include pulmonary artery catheterization and/or transoesophageal echocardiography. During cardiac surgery the risk for elderly individuals is increased; in particular, the central nervous system is more often compromised in the elderly than in younger patients. However, elderly patients without significant co-morbidity have a mortality rate comparable to that of younger patients.

Potential methods to prevent interstitial fibrosis in renal disease

Almost all forms of end stage renal disease (ESRD) are characterised by progressive interstitial fibrosis and tubular atrophy. Since most forms of chronic renal failure are initiated by inflammatory processes, anti-inflammatory strategies can be successful, if initiated early, in preventing progression of the disease process. Unfortunately, in most cases the disease is only detected clinically following robust progression of interstitial fibrosis. In these patients, control of secondary risk factors, such as hypertension and hyperglycaemia, can slow the progression rate but cannot stop the process completely. Certainly, ACE inhibitors remain the mainstay of preserving renal function. However, additional therapies are needed for the effective treatment of progressive renal fibrosis. A number of compounds have shown some very potent antifibrotic properties in vitro and in vivo, and are currently undergoing further evaluation. This review discusses the most promising among them. However, few of the therapeutic agents discussed here have been tested clinically. Studies evaluating the potential of a number of these have just commenced whereas for many others clinical use is still many years away. However, some very promising reagents may enhance our clinical arsenal within a relatively short period of time.