Liver transplantation for alcoholic liver disease: a survey of transplantation programs in the United States

Small human hepatocytes in rotary culture for treatment of alcohol addicts? A pilot study

BACKGROUND

Current approaches to support alcohol addict and/or benzodiazepine-treated patients with liver failure include culturing human cells to take over basic metabolic functions for a certain time.

METHODS

Small human hepatocytes (SH) were grown in a rotary cell culture system, and their potential to metabolize alcohol and the benzodiazepines oxazepam and diazepam was evaluated. Control experiments were performed with SV40-immortalized HEP cells and cell respective drug-free media.

RESULTS

Our results show that SH in rotary culture are able to metabolize ethanol in reasonable amounts compared with evaporation controls (p<0.01). Moreover, SH are also able to metabolize oxazepam and diazepam which proves their ability to perform conjugation and the presence of functional cytochrome P450 enzymes. Basic metabolic activities such as glucose consumption, albumin and urea production are not significantly influenced by the drugs used, which is a precondition for clinical use of these cells. Significantly increased lactate dehydrogenase release indicates enhanced cell death in cultures of SH incubated with either ethanol (p<0.05) or diazepam (p<0.005), but stable viability at or above 90% suggests that cell proliferation is able to keep up with drug-induced cell death.

CONCLUSION

Our preliminary study provides evidence that SH are basically suited to support alcohol-abusing and/or benzodiazepine-treated patients undergoing liver failure.

[MARS (Molecular Absorbent Recirculating System) as hepatic extracorporeal care in serious acute liver failure of alcoholic etiology]

Acute liver failure with criteria of seriousness and alcoholic etiology is a picture of worldwide distribution, with an elevated mortality, of approximately 50%, that requires admission to the ICU. Acute serious alcoholic hepatitis is defined by a Maddrey score value > 32 and/or spontaneous encephalopathy. Together with the classical treatment with corticosteroids and nutritional supplements, alcoholic abstinence and others such as anti-TNF therapy, we introduce MARS (Molecular Adsorbent recirculating System) as a extracorporeal liver assistance system with detoxification function, that is presented as a support measure that makes it possible to maintain the patient in good conditions until an organ becomes available or until the functional recovery of the native liver. In our case, MARS has shown some spectacular results and above all, results maintained over time, associated to the rest of the therapeutic measures characteristic of this disease.

Alcoholic hepatitis

Alcoholic hepatitis is a form of hepatic injury that carries a significant morbidity and mortality. The clinical presentation is that of fatigue, malaise, and jaundice in individuals who have abused excessive quantities of alcohol. Severity at presentation, traditionally calculated using the Maddrey Discriminant Function, determines outcome; the short-term mortality can be exceptionally high, with many persons dying within 1 month of hospitalization. This article summarizes the epidemiology, pathogenesis, pathology, and clinical features of alcoholic hepatitis. Prognostic scoring systems and therapeutic options receive special emphasis.

Liver transplantation for alcoholic liver disease: a systematic review of psychosocial selection criteria

AIMS

To examine the evidence base for psychosocial selection criteria for liver transplant candidates with alcoholic liver disease.

METHOD

Systematic review using three electronic databases supplemented by hand searches.

RESULTS

Out of 96 published studies, 22 were included. All but one were cohort design, most were retrospective, single centre, and small sample. Methodology varied considerably, such that meta-analysis was not feasible.

CONCLUSIONS

Social stability, no close relatives with an alcohol problem, older age, no repeated alcohol-treatment failures, good compliance with medical care, no current polydrug misuse, and no co-existing severe mental disorder have all been associated with future abstinence in more studies than not, in those that examined these variables. Duration of preoperative abstinence was a poor predictor. We recommend that, if predicting future abstinence is considered necessary by transplant teams, a standardized approach is agreed and deployed amongst transplant units, then audited and reviewed.

Is alcoholic hepatitis an indication for transplantation? Current management and outcomes

1. In the absence of treatment, 50% of patients with severe alcoholic hepatitis (AH) [Maddrey function (DF) >or= 32] die 2 months later. Among patients with severe AH treated by corticosteroids, 80% had 2-month survival. Pentoxifylline is considered by some investigators to be an alternative option to corticosteroids. 2. Non-responders to corticosteroids (NRCs) have poor survival and require new strategies. Liver transplantation should be considered in order to improve survival of non-responders to therapeutic agents. 3. Prognostic models such as the Model for End-Stage Liver Disease (MELD) and DF are useful tools for predicting short-term mortality of patients with severe AH. Specific models taking into account the particular settings of treated patients are warranted. 4. In an era of organ shortage, use of liver transplants in patients with severe AH may negatively affect the public attitude on transplantation and organ donation, and may cause reluctance on the part of clinicians to modify guidelines for alcoholic patients. 5. Therefore, a reasonable approach would be to carry out only pilot studies on only a small cohort of patients to determine whether transplantation improves survival in patients with severe AH.

Long-term follow-up of patients with alcoholic liver disease after liver transplantation in Sweden: impact of structured management on recidivism

OBJECTIVE

No systematic evaluation has been performed previously in the Scandinavian countries on patients transplanted for alcoholic liver disease (ALD). Data are limited on the impact of structured management of the alcohol problem on the risk of recidivism following transplantation in ALD.

MATERIAL AND METHODS

A total of 103 ALD patients were compared with a control group of patients with non-alcoholic liver disease (NALD). The recidivism rates for ALD patients transplanted between 1988 and 1997 as well as after 1998 (institution of structured management) were compared.

RESULTS

The median follow-up was 31 (6-60) months in the ALD group and 37 (12-63) months in the control group (NS). The overall survival rates at 1- and 5 years were, respectively, 81% and 69% for the ALD group and 87% and 83% for the non-alcoholic group. The proportion of patients with Child-Pugh C (75%) was higher in ALD patients than in NALD patients (44%) (p<0.01). Thirty-two (33%) ALD patients resumed taking some alcohol after transplantation; 17 patients (18%) were heavy drinkers. A multivariate analysis showed that: sex, age, marital and employment status, benzodiazepine use and a history of illicit drug abuse did not predict the risk of alcohol relapse post-Tx. Nineteen out of 40 (48%) patients transplanted before the start of structured management had resumed alcohol but 13 (22%) out of 58 after this intervention (p=0.002).

CONCLUSIONS

ALD is a good indication for liver transplantation, with similar results in the ALD patients. Structured management of the alcohol problem before and after transplantation is important in minimizing the risk of recidivism.

Pretransplant screening of sobriety with carbohydrate-deficient transferrin in patients suffering from alcoholic cirrhosis

Sufficient assessment of potential candidates for orthotopic liver transplantation (OLT) is the most important factor for a low alcohol relapse rate after transplantation in patients suffering from alcoholic cirrhosis. In the current study the efficiency of pretransplant screening with carbohydrate-deficient transferrin (CDT) was analysed in patients on the waiting list for OLT. A prospective study was performed in 44 patients who had undergone OLT for alcoholic cirrhosis. All patients had had pretransplant assessment by a specialist psychologist and were found to have no problems with alcohol. Pre- and post-transplant CDT monitoring was performed. Overall, 790 CDT values were measured in the study population. The median observation period was 2.1 months before and 41.2 months after transplantation, respectively. In 35 patients (80%) pretransplant CDT values were found to be above the reference value, but only one patient suffered an alcohol relapse after transplantation. Of the nine patients (20%) who demonstrated normal CDT before transplantation, two suffered an alcohol relapse after transplantation. CDT is a very useful marker for the monitoring of an alcohol relapse in patients following OLT for alcoholic cirrhosis, as has been previously indicated. However, CDT does not appear to be useful as a pretransplant screening marker for selection of potential transplant candidates suffering from alcoholic cirrhosis.

Liver transplantation for alcoholic liver disease: current concepts and length of sobriety

1. The 1-year and 5-year actuarial survival rates following liver transplantation for patients with alcoholic liver disease are 82% and 68%, respectively, in the United States and 85% and 70%, respectively, in Europe. These survival rates are similar to the outcomes of patients who undergo transplantation for other types of chronic liver disease. 2. Posttransplant improvements in health-related quality of life are similar in patients who undergo transplantation for alcoholic liver disease compared to those who undergo transplantation for other causes of end-stage liver disease. 3. Approximately 20% of patients who undergo transplantation for alcoholic liver disease use alcohol posttransplant, with one-third of these individuals exhibiting repetitive or heavy drinking. Surprisingly, little evidence exists to document a significant detrimental effect on graft or patient survival associated with resumption of drinking. 4. There are few reliable predictors of relapse in alcoholic patients after liver transplantation. Although not supported by all studies, abstinence of fewer than 6 months prior to transplantation may be a reasonable predictor of recidivism and is widely employed as a criterion for listing for liver transplantation. There are no good data to determine if some patients with sobriety fewer than 6 months might benefit from liver transplantation.

Analysis of factors that predict alcohol relapse following liver transplantation

Alcoholic liver disease has become a major indication for liver transplantation in the United States. Factors that predict alcohol relapse after liver transplantation are poorly defined. The aim of our study was to identify predictors of alcohol relapse in patients undergoing liver transplantation for alcoholic liver disease. One hundred and eleven patients undergoing liver transplantation for alcoholic liver disease between 1985 and 1999 were identified from our database. Patients were selected for liver transplantation if their risk of relapse was felt to be low by the transplant team. A chart review was conducted to determine if relapse had occurred, the presence or absence of factors that were thought to predict relapse, and survival. Demographic and psychosocial variables were analyzed using univariate and multivariate logistic regression to identify independent predictors of relapse. The median duration of abstinence before liver transplantation was 15 months (range: 1-120). Hepatitis C virus was present in 64% of patients. A family history of alcoholism in a first-degree relative was identified in 38%, and 78% received treatment for alcoholism before liver transplantation. The mean duration of follow-up was 44.1 +/- 3.7 months. There were 29 deaths (26%) overall. Seventeen patients (15%) returned to alcohol use. On multivariate analysis a family history of alcoholism was found to be an independent predictor of alcohol relapse (P=.03). Further prospective studies are needed to examine this association in greater detail to provide targeted treatment for alcoholism both before and after liver transplantation.

Early change in bilirubin levels is an important prognostic factor in severe alcoholic hepatitis treated with prednisolone

Early identification of patients with severe (discriminant function >or=32) biopsy-proven alcoholic hepatitis (AH) who are not responding to corticosteroids would be clinically relevant. Our goal was to develop simple criteria that will help physicians to promptly identify nonresponders to corticosteroids. A total of 238 patients were included. We used 6 months survival as an end point because of the rule requiring 6 months for listing alcoholic patients for transplantation. Overall survival at 1 and 6 months was 85% +/- 2.3% and 64.3% +/- 3.3%, respectively. An early change in bilirubin levels (ECBL) at 7 days (defined as bilirubin level at 7 days lower than bilirubin level on the first day of treatment) was observed in 73% of patients. At 7 days, in patients with ECBL, bilirubin decreased (84 +/- 75 micromol/L [4.94 +/- 4.40 mg/dL]), whereas it increased in patients without ECBL (76.5 +/- 77 micromol/L [4.50 +/- 4.54 mg/dL], P <.0001). Ninety-five percent of patients with ECBL continued to have improved liver function during treatment. At 6 months, survival of patients with ECBL was significantly higher than that of patients without ECBL, 82.8% +/- 3.3% versus 23% +/- 5.8%, P <.0001. On multivariate analysis, ECBL, discriminant function and creatinine were independent prognostic variables, and ECBL had the most important prognostic value. In conclusion, ECBL is a very simple predictive factor for identifying nonresponders. A recommendation to discontinue corticosteroids after 7 days in patients without ECBL, suggested by our results, awaits additional confirmation.

Dental management of the (solid) organ transplant patient

The need to provide dental care for organ transplant candidates and recipients will increase in conjunction with the continued expansion of the use of organ transplantation. For the transplant candidate, dental care usually requires application of practice standards that fall within the scope of management of the severely medically compromised patient. There are, however, few guidelines and no clinical trials or outcomes assessments that address appropriate care for transplant recipients. Furthermore, despite the high rate of infectious complications among patients who have received organ transplants, there is little evidence that dental disease contributes to this risk. This article reviews the current status of dental care practices that have been recommended and presents a rationale that can be applied as the basis for guidelines and recommendations for the treatment of the organ transplant patient.

Influence of superimposed alcoholic hepatitis on the outcome of liver transplantation for end-stage alcoholic liver disease

BACKGROUND/AIMS

Alcoholic cirrhosis is a common indication for liver transplantation. The present study was aimed to assess the influence of superimposed alcoholic hepatitis on the outcome of liver transplantation in patients with alcoholic cirrhosis.

METHODS

Survival rates of 68 patients transplanted for alcoholic cirrhosis were compared with those of 101 patients transplanted for miscellaneous causes. Within the alcoholic group, explanted livers were searched for data of acute alcoholic hepatitis. The survival rate of patients with alcoholic hepatitis superimposed on liver cirrhosis was compared to that of patients with liver cirrhosis alone. Clinical severity of alcoholic hepatitis was assessed with Maddrey's score.

RESULTS

Survival was similar in alcoholics and patients with other causes of liver disease. Among patients transplanted for alcoholic cirrhosis, survival was similar in patients with superimposed alcoholic hepatitis (n=36) and in cases with liver cirrhosis alone (n=32). There was no difference in survival between patients with mild (n=26) and severe (n=10) alcoholic hepatitis. Seven alcoholics (10%) returned to ethanol consumption. Recidivism was not associated with either alcoholic hepatitis in the explanted liver or graft loss.

CONCLUSIONS

Survival after liver transplantation in patients with alcoholic cirrhosis plus alcoholic hepatitis detected in the explanted liver is similar to that of patients transplanted for other reasons. Even the presence of severe alcoholic hepatitis does not worsen the outcome of liver transplantation for end-stage alcoholic liver disease.

Liver transplantation in patients with alcohol and other substance use disorders

It is unfortunate that LT is not the ultimate sobering experience. LT patients can and do relapse; however, relapse to alcohol or substance use should no more be considered a failure of LT than the recurrence of HCV after LT. It is a phenomenon of their addiction. As a group, the survival and outcomes of patients undergoing LT for ALD are not significantly different from those undergoing LT for other causes. The fact that few patients return to heavy and deleterious alcohol or substance use attests to the success of programs in selecting patients capable of caring for themselves and their livers after LT. In the pre-LT phase, establishing the correct addiction diagnosis is essential so that those at highest risk can be carefully monitored. Although information is emerging about other risk factors for relapse, the authors caution against considering patients with these characteristics as being categorically unfit for LT. Each individual is unique, and such factors should guide clinical decision making rather than being absolute contraindications. After LT, clinical interviews, preferably by a trained psychiatric physician or clinician, are essential to monitoring alcohol and substance use, and surveillance early on is required. Much work needs to be done with respect to substance use and relapse after LT because few studies have explored these issues. In addition, the special treatment needs of those who relapse has not been addressed. Treatment research is underway but has relied on traditional strategies that are not always applicable to LT recipients. Further areas to improve clinical care include improving health behaviors, specifically, smoking cessation. The authors anticipate that, in the near future, the ongoing work in this area will provide information and guidance to physicians and clinicians caring for these unique patients.

Drinking behavior and motivation for treatment among alcohol-dependent liver transplant candidates

Alcohol misuse is the second most common indication for liver transplantation in the United States. Our post-transplant alcoholism treatment trial suggested that current interventions might not be transferable to liver transplantees. We sought to identify differences between patients awaiting liver transplantation and alcoholics entering treatment without severe liver disease. Thirty transplant patients were compared to thirty naltrexone study patients on medical status, alcohol and drug use, alcohol craving, motivation for treatment, psychiatric symptoms, and psychosocial problems. Lifetime alcohol consumption was greater for transplant patients compared to naltrexone patients. In contrast to the naltrexone group, transplant patients denied craving for alcohol and showed little motivation for alcoholism treatment. Groups did not differ on other psychosocial measures. Liver transplant patients differ from patients in alcoholism treatment trials on measures of alcohol consumption, alcohol craving and motivation for treatment. Alcoholism interventions should accommodate their medical condition and boost motivation for continued abstinence.

Liver transplantation for alcoholic liver disease

Although increasing numbers of alcoholic patients are being referred to liver transplant centres, liver transplantation for alcoholic liver disease still remains controversial, essentially because we are in an era of organ shortage. In fact, the main issue is the likelihood of relapse and its influence on outcome, because it is the possibility of returning to alcohol use that separates patients with alcoholic liver disease from those with other forms of chronic liver disease. In all proposed clinical guidelines of indications for referral and assessment for liver transplantation for alcoholic liver disease, the authors emphasize the risk of alcoholism recurrence and, thus, a multidisciplinary approach is required to select patients who are likely to comply with follow-up and not return to a damaging pattern of alcohol consumption after transplantation. It emerges from all clinical studies that when we take into account the usual criteria of success for liver transplantation, i.e. patient and graft survival, rejection rate and infection rate, alcoholic liver disease is a good indication for liver transplantation. Predictive factors for alcoholic relapse after liver transplantation have been assessed in numerous studies, often with contradictory results making these difficult to analyse and compare. Several predictive factors for alcoholic relapse have been studied: length of abstinence before transplantation, associated psychiatric problems, social conditions, associated drug addiction, age. Abstinence after transplantation is the goal, but the necessary treatment for alcoholic disease can result in considerable improvement, even when complete abstinence is not achieved. Finally, the good results obtained with liver transplantation for alcoholic liver disease should help us to educate the general population about alcoholic disease.

Liver transplantation for alcoholic cirrhosis: long term follow-up and impact of disease recurrence

BACKGROUND

Alcoholic liver disease has emerged as a leading indication for hepatic transplantation, although it is a controversial use of resources. We aimed to examine all aspects of liver transplantation associated with alcohol abuse.

METHODS

Retrospective cohort analysis of 123 alcoholic patients with a median of 7 years follow-up at one center.

RESULTS

In addition to alcohol, 43 (35%) patients had another possible factor contributing to cirrhosis. Actuarial patient and graft survival rates were, respectively, 84% and 81% (1 year); 72% and 66% (5 years); and 63% and 59% (7 years). After transplantation, 18 patients (15%) manifested 21 noncutaneous de novo malignancies, which is significantly more than controls (P=0.0001); upper aerodigestive squamous carcinomas were overrepresented (P=0.03). Thirteen patients had definitely relapsed and three others were suspected to have relapsed. Relapse was predicted by daily ethanol consumption (P=0.0314), but not by duration of pretransplant sobriety or explant histology. No patient had alcoholic hepatitis after transplantation and neither late onset acute nor chronic rejection was significantly increased. Multiple regression analyses for predictors of graft failure identified major biliary/vascular complications (P=0.01), chronic bile duct injury on biopsy (P=0.002), and pericellular fibrosis on biopsy (P=0.05); graft viral hepatitis was marginally significant (P=0.07) on univariate analysis.

CONCLUSIONS

Alcoholic liver disease is an excellent indication for liver transplantation in those without coexistent conditions. Recurrent alcoholic liver disease alone is not an important cause of graft pathology or failure. Potential recipients should be heavily screened before transplantation for coexistent conditions (e.g., hepatitis C, metabolic diseases) and other target-organ damage, especially aerodigestive malignancy, which are greater causes of morbidity and mortality than is recurrent alcohol liver disease.

Alcoholism treatment after liver transplantation: lessons learned from a clinical trial that failed

Alcoholic liver disease is the second most common indication for liver transplantation in the United States. The lack of alcoholism treatment studies led us to study motivational enhancement therapy (MET) plus naltrexone after transplant. The authors could not complete this study. Sixty alcoholic patients were to receive MET plus naltrexone or placebo for 6 months. Fifty men and 5 women were screened. Nine died and 15 were not approached. Of 31 approached, 20 were ineligible, 11 refused, and 5 entered but dropped out before completion. Barriers to posttransplant alcoholism included infirmity, intensive medical management, and denial for alcoholism treatment. Because 30%-50% of alcoholic patients drink after transplant, the authors suggest using MET alone pretransplant.

Interpreting the significance of drinking by alcohol-dependent liver transplant patients: fostering candor is the key to recovery

Few studies have examined the value of treating alcohol addiction either before or after liver transplantation. Nevertheless, most liver transplant programs and many insurance companies require 6 months to 1 year of abstinence from alcohol as a condition of eligibility for liver transplantation (the 6-month rule). We believe there are potentially harsh clinical consequences to the implementation of this rule. For example, the natural history of alcohol use disorders often involves brief fallbacks to drinking ("slips"), but when alcoholic liver transplant candidates slip, most are removed from consideration for transplantation or are required to accrue another 6 months of sobriety. Because there is no alternative treatment to liver transplantation for most patients with end-stage liver disease, the 6-month rule could be lethal in some circumstances. In this review, we survey the literature concerning the ability of the 6-month rule to predict drinking by alcoholic patients who undergo liver transplantation and examine its impact on the health consequences of drinking before and after liver transplantation. We believe that fostering candor between the alcoholic patient and the transplant team is the key to recovery from alcoholism. We conclude that it is unethical to force alcoholic liver patients who have resumed alcohol use while waiting for or after transplantation to choose between hiding their drinking to remain suitable candidates for transplantation or risk death by asking for treatment of alcoholism. Consequently, we advocate a flexible approach to clinical decision making for the transplant professional caring for an alcoholic patient who has resumed drinking and provide specific guidelines for patient management.

Liver transplantation. American Association for the Study of Liver Diseases

Liver transplantation has revolutionized the care of patients with end-stage liver disease. Liver transplantation is indicated for acute or chronic liver failure from any cause. Because there are no randomized controlled trials of liver transplantation versus no therapy, the efficacy of this surgery is best assessed by carefully comparing postoperative survival with the known natural history of the disease in question. The best examples of this are in primary biliary cirrhosis and primary sclerosing cholangitis, for which well-validated disease-specific models of natural history are available. There are currently relatively few absolute contraindications to liver transplantation. These include severe cardiopulmonary disease, uncontrolled systemic infection, extrahepatic malignancy, severe psychiatric or neurological disorders, and absence of a viable splanchnic venous inflow system. One of the most frequently encountered contraindications to transplantation is ongoing destructive behavior caused by drug and alcohol addiction. The timing of the surgery can have a profound impact on the mortality and morbidity of patients undergoing liver transplantation. Because of the long waiting lists for donor organs, the need to project far in advance when transplantation might be required has proven to be one of the greatest challenges to those treating patients with end-stage liver disease. Three important questions must be addressed in a patient being considered for liver transplantation: (1) when should the patient be referred for possible transplantation? (2) when should the patient be listed for transplantation? and (3) when is the patient too sick to have a reasonable chance of surviving the perioperative period?

Increased incidence of oropharyngeal squamous cell carcinomas after liver transplantation for alcoholic cirrhosis

BACKGROUND

THE aim of this study was to describe the features of posttransplantation tumors observed in a series of liver transplant recipients with special reference to patients receiving a transplant for alcoholic cirrhosis.

METHODS

Among 171 consecutive liver transplant recipients, 90 patients who had received a first liver allograft for cirrhosis were studied. After liver transplantation, detection of de novo malignancies was prospectively undertaken and the characteristics of the patients in whom tumors occurred were compared with those in whom tumors did not develop.

RESULTS

With a follow-up of 45.2+/-21.2 months, 11 tumors were observed in 90 patients (overall incidence of 12.2%). The incidence of tumors was higher in patients receiving a transplant for alcoholic cirrhosis than in patients receiving a transplant for nonalcoholic cirrhosis (26.7% vs. 5.0%, P<0.01). Squamous cell carcinoma (SCC) of the oropharynx or esophagus and posttransplant lymphoproliferative disorders were mainly observed. SCC (uvula in two cases, tongue in one case, esophagus in one case, pharynx in one case) occurred exclusively in patients transplanted for alcoholic cirrhosis (16.7% vs. 0%, P=0.001). The incidence of posttransplant lymphoproliferative disorders was similar in alcoholics and nonalcoholics (6.7% vs. 5%, NS). Survival was not influenced by the occurrence of SCC.

CONCLUSION

The incidence of oropharyngeal SCC could be high in patients receiving a transplant for alcoholic cirrhosis. This could be due to an additional effect of posttransplantation immunosuppression in patients exposed to alcohol and tobacco before transplant. Careful posttransplantation screening of oropharyngeal SCC is warranted after liver transplantation for alcoholic cirrhosis.

Alcoholic liver disease: proposed recommendations for the American College of Gastroenterology

OBJECTIVE

The objective of this work was to develop practice guidelines for the management of alcoholic liver disease.

METHOD

A computerized search using the Medline Data Base from 1966-July 1997 was performed with the search headings; alcohol, alcoholic hepatitis, alcoholic liver disease, liver transplant, diagnosis, epidemiology, human, and English only. All randomized controlled trials, case-control studies, and meta-analyses were read in depth. A manual search was also done using references from each retrieved report, review articles, editorials, postgraduate course syllabi, and textbooks. In the subsequent review, evidence was evaluated using a hierarchical scale with randomized, controlled trials given the most importance. Abstracts presented at national meetings were included only when unique data were obtained from those studies.