Carotid endarterectomy for prevention of stroke.

Carotid endarterectomy, a frequently performed operation, has been used as a strategy for preventing stroke in patients with carotid bifurcation disease. The safety and efficacy of the operation were recently challenged by a number of sources. Three major responses to this challenge were to retrospectively review the natural history of carotid bifurcation disease compared with the immediate and long-term results of carotid endarterectomy, to initiate 6 prospective randomized trials to determine the efficacy of carotid endarterectomy for a variety of indications, and to develop appropriateness initiatives and guidelines for using this surgical procedure by organizations concerned with health care policy. I review the current status of these 3 areas of endeavor. In those areas where studies are complete, carotid endarterectomy has been shown to be highly effective in reducing stroke risk. Risk reduction has ranged from 66% to 80% compared with medical management. Based on these sources and findings, I present a list of indications for the operation for surgeons who are able to do the operation safely and within the guidelines established by the Stroke Council of the American Heart Association.     

Liver transplantation in patients with alcoholic cirrhosis: selection criteria and rates of survival and relapse.

OBJECTIVE--To evaluate the outcome of liver transplantation in patients with alcoholic cirrhosis with respect to selection criteria, survival, and evidence suggesting a return to harmful drinking. DESIGN--Nine year retrospective study. SETTING--Cambridge and King''s College Hospital liver transplant programme. SUBJECTS--24 Patients (three women, 21 men) with alcoholic cirrhosis. MAIN OUTCOME MEASURES--Survival, rehabilitation, and clinical and laboratory evidence of a return to harmful drinking after transplantation. RESULTS--15 Patients were selected for transplantation because of repeated admission to hospital for the complications of advanced portal hypertension despite abstinence, and six because they had a hepatocellular carcinoma superimposed on alcoholic cirrhosis. Three patients who were not abstinent received transplants. The one year survival rate was 66%, and of the 18 patients surviving at least three months, 17 had been rehabilitated. In three patients laboratory variables and histological examination of the liver suggested a return to drinking, though they did not admit to taking alcohol. These patients represented the only cases in the series that were not abstinent before transplantation. CONCLUSIONS--The survival and rehabilitation of patients who received transplants for alcoholic cirrhosis compared favourably with those of patients who received transplants for cirrhosis of other aetiology. The criteria for selection for liver transplantation in patients with alcoholic cirrhosis should include recurrent complications related to severe portal hypertension despite maximum medical treatment in addition to a minimum period of six months of abstinence before transplantation.     

Analysis of survival rates of sportsmen utilizing Cutler-Ederer method.

Few studies have been conducted in Japan on the relationship between sports and the length of human life, i.e. the life-prolonging effect of exercise. In this paper, we conducted such research on 3,113 male graduates of a national university having a faculty of physical education. The subjects were divided according to their academic majors, which included physical education, humanities, and science courses. The following results were obtained: 1) Comparison of ages at death showed that physical education majors were distinctly represented in lower age groups. 2) Comparison of average ages at death by dividing the subjects into 20-year intervals according to their years of birth, revealed that physical education majors do not necessarily live longer and tend to die relatively young. 3) Comparison of average ages at death, including death by war, indicated that physical education majors lived 8.572 and 7.792 years less than humanities and science course majors, respectively. When death by war was excluded, the results were 6.189 and 5.548 years, respectively. Both results were statistically significant. 4) Comparison of cumulative survival rates utilizing Cutler-Ederer method showed that the rates of survival of physical education majors were low.     

Estimation of survival rates in haematophagous insects

Estimation of the survival rate through a gonotrophic cycle is an important factor in determining the vectorial capacity of a population of haematophagous insects in a disease cycle. Most methods used to calculate survival rates make stringent assumptions which may not be valid for all species. Birley and colleagues used a time series analysis of samples collected over several consecutive days, the lagged parous rate. Here, we use a simulation model to investigate (i) the length of data series needed and (ii) the consequences of failures in the assumptions of this method for the estimated survival rate. The accuracy of the estimated survival rate per cycle was high with sample periods of 10-100 days. The standard deviation (a measure of precision) decreased with the length of the sample period. When random sampling efficiency was included, the accuracy remained high but the estimates were less precise (larger standard deviations). If the sampling was biased in favour of either nulliparous or parous females, estimates of the survival rate were not accurate. The relationship between estimated survival rate, bias in collection, and true survival rate was non-linear. Thus, correction for the bias requires (i) prior knowledge of the direction and the severity of the bias and (ii) an independent estimate of the survival rate. This method of estimating survival rates is less accurate when the collection method is biased for or against parous females, although robust to other assumptions.     

Causes and consequences of increase in child survival rates: ethnoepidemiology among the Hmong of Thailand.

The Hmong "hill tribe" minority in Thailand has much higher exposure to factors usually associated with risk of child mortality (high fertility, low status of women, low education, less use of modern medical care for births, exposure to warfare, economic and physical disruption, and poor hygienic conditions) than the rural ethnic Thai population. Nonetheless, infant mortality has declined from over 120 per 1000 to under 50 per 1000 live births among both these populations in the past 30 years. The reason for the rapid increase in child survival among the Hmong appears to be better access to and more use of modern curative and preventive medical care associated with road construction rather than major changes in social or hygienic conditions. Conventional wisdom suggests that high fertility is both a cause and a consequence of high infant and child mortality and that parents will not reduce fertility until they see that mortality has declined. Most Hmong parents recognize the decline in child mortality and attribute it to better access to modern medical care. Most Hmong parents also say that, if they were starting to have children now, they would want to have fewer children. Fear of child death is infrequently mentioned as a motive for having more children, and the perceived decline in child mortality is rarely mentioned as a reason for reduced fertility. Most Hmong parents explain their desired family size in terms of economic conditions rather than perceived risk of child mortality. Results of this study suggest that fertility and child mortality can vary independently of one another and that major reductions in child mortality can be accomplished without waiting for major social changes (e.g., improved education or status of women) or major reductions in fertility.     

Estimating survival and adoption rates of dependent juveniles

Population growth and fitness are typically most sensitive to adult survival in long‐lived species, but variation in recruitment often explains most of the variation in fitness, as past selection has canalized adult survival. Estimating juvenile survival until age of independence has proven challenging, because marking individuals in this age class may directly affect survival. For Greater Sage‐grouse, uniquely marking juveniles in the first days of life likely results in adverse effects to survival, detection of juveniles is not perfect, and females adopt juveniles from other parents. These challenges are encountered by researchers studying avian and mammalian species with similar life histories, yet methods do not exist that explicitly estimate all these components of the recruitment process. We propose a novel data collection method and demographic model to simultaneously estimate rates of detection, survival, and adoption of juvenile individuals. Using multiple cameras to film the beginning of juvenile activity on specific days, we obtained counts of juveniles associated with marked females. Increases of juveniles to broods provided information that enabled us to estimate rates of adoption that can be applied at the population level. Losses from broods informed apparent survival. These losses could be attributed to death, or they could be chicks that were adopted by other females. We found evidence that apparent survival of juveniles was influenced by localized weather patterns when chicks were young. Similarly, we found that young chicks were more susceptible to the adverse effect of attending females being flushed by an observer. Both of these patterns diminished quickly as chicks aged. We provide the first‐ever estimates of interval‐specific adoption rates. Our results suggest that researchers should be cautious when designing studies to estimate juvenile survival. More importantly, they provide insight into adoption, a behavior that has been known to exist for decades.     

Headache after carotid endarterectomy.

Forty-eight hours after undergoing a successful right carotid endarectomy a patient complained of headache in and behind the right eye radiating to the temple and forehead. The onset of headache was sudden, and the pain was severe and throbbing. After three weeks of regular four- to eight-hour attacks each day the headaches gradually became less frequent. Two months after operation they had disappeared completely. Headache as a complication of endarterectomy is rare, but typically it is vascular and subsides spontaneously in one to six months. If a predisposition to migraine were a precipitating factor many more cases would be expected. No possible explanation for for headache after carotid prearterectomy can account adequately for its apparent rarity.     

Encouraging survival rates in patients with acute myocardial infarction treated with an intra-aortic balloon pump

Objective

To evaluate a 30-day and long-term outcome of patients with acute myocardial infarction (AMI) treated with intra-aortic balloon pump (IABP) counterpulsation and to identify predictors of a 30-day and long-term all-cause mortality.

Methods

Retrospective cohort study of 437 consecutive AMI patients treated with IABP between January 1990 and June 2004. A Cox proportional hazards model was used to identify predictors of a 30-day and long-term all-cause mortality.

Results

Mean age of the study population was 61 ± 11 years, 80% of the patients were male, and 68% had cardiogenic shock. Survival until IABP removal after successful haemodynamic stabilisation was 78% (n = 341). Cumulative 30-day survival was 68%. Median follow-up was 2.9 years (range, 6 months to 15 years). In patients who survived until IABP removal, cumulative 1-, 5-, and 10-year survival was 75%, 61%, and 39%, respectively. Independent predictors of higher long-term mortality were prior cerebrovascular accident (hazard ratio (HR), 1.8; 95% confidence interval (CI), 1.0–3.4), need for antiarrhythmic drugs (HR, 2.3; 95% CI, 1.5–3.3), and need for renal replacement therapy (HR, 2.3; 95% CI, 1.2–4.3). Independent predictors of lower long-term mortality were primary percutaneous coronary intervention (PCI; HR, 0.6; 95% CI, 0.4–1.0), failed thrombolysis with rescue PCI (HR, 0.5; 95% CI, 0.3–0.9), and coronary artery bypass grafting (HR, 0.3; 95% CI, 0.1–0.5).

Conclusions

Despite high in-hospital mortality in patients with AMI treated with IABP, a favourable number of patients survived in the long-term. These results underscore the value of aggressive haemodynamic support of patients throughout the acute phase of AMI.     

Patterns and processes in shorebird survival rates: a global review

Changes in demographic rates underpin changes in population size, and understanding demographic rates can greatly aid the design and development of strategies to maintain populations in the face of environmental changes. However, acquiring estimates of demographic parameters at relevant spatial scales is difficult. Measures of annual survival rates can be particularly challenging to obtain because large‐scale, long‐term tracking of individuals is difficult and the resulting data contain many inherent biases. In recent years, advances in both tracking and analytical techniques have meant that, for some taxonomic groups, sufficient numbers of survival estimates are available to allow variation within and among species to be explored. Here we review published estimates of annual adult survival rates in shorebird species across the globe, and construct models to explore the phylogenetic, geographical, seasonal and sex‐based variation in survival rates. Models of 295 survival estimates from 56 species show that survival rates calculated from recoveries of dead individuals or from return rates of marked individuals are significantly lower than estimates from mark–recapture models. Survival rates also vary across flyways, largely as a consequence of differences in the genera that have been studied and the analytical methods used, with published estimates from the Americas and from smaller shorebirds (Actitis, Calidris and Charadrius spp.) tending to be underestimated. By incorporating the analytical method used to generate each estimate within a mixed model framework, we provide method‐corrected species‐specific and genus‐specific adult annual survival estimates for 52 species of 15 genera.