Mapping Short Warwick and Edinburgh Mental Wellbeing Scale (SWEMWBS) to Recovering Quality of Life (ReQoL) to estimate health utilities

BACKGROUND

The Short Warwick and Edinburgh Mental Wellbeing Scale (SWEMWBS) is a widely used non-preference-based measure of mental health in the UK. The primary aim of this paper is to construct an algorithm to translate the SWEMWBS scores to utilities using the Recovering Quality of Life Utility Index (ReQoL-UI) measure.

METHODS

Service users experiencing mental health difficulties were recruited in two separate cross-sectional studies in the UK. The following direct mapping functions were used: Ordinary Least Square, Tobit, Generalised Linear Models. Indirect (response) mapping was performed using seemingly unrelated ordered probit to predict responses to each of the ReQoL-UI items and subsequently to predict using UK tariffs of the ReQoL-UI from SWEMWBS. The performance of all models was assessed by the mean absolute errors, root mean square errors between the predicted and observed utilities and graphical representations across the SWEMWBS score range.

RESULTS

Analyses were based on 2573 respondents who had complete data on the ReQoL-UI items, SWEMWBS items, age and sex. The direct mapping methods predicted ReQoL-UI scores across the range of SWEMWBS scores reasonably well. Very little differences were found among the three regression specifications in terms of model fit and visual inspection when comparing modelled and actual utility values across the score range of the SWEMWBS. However, when running simulations to consider uncertainty, it is clear that response mapping is superior.

CONCLUSIONS

This study presents mapping algorithms from SWEMWBS to ReQoL as an alternative way to generate utilities from SWEMWBS. The algorithm from the indirect mapping is recommended to predict utilities from the SWEMWBS.

A critical review and analysis of the context, current burden, and application of policy to improve cancer equity in Ghana

BACKGROUND

Cancer causes a major disease burden worldwide. This is increasingly being realised in low and middle-income countries, which account disproportionately for preventable cancer deaths. Despite the World Health Organization calling for governments to develop policies to address this and alleviate cancer inequality, numerous challenges in executing effective cancer policies remain, which require consideration of the country-specific context. As this has not yet been considered in Ghana, the aim of this review was to bring together and critique the social-environmental, health policy and system factors to identifying opportunities for future health policies to reduce cancer burden in the Ghanian context. A critical policy-focused review was conducted to bring together and critique the current health systems context relating to cancer in Ghana, considering the unmet policy need, health system and social factors contributing to the burden and policy advances related to cancer.

CONCLUSION

The findings highlight the changing burden of cancer in Ghana and the contextual factors within the socio-ecosystem that contribute to this. Policies around expanding access to and coverage of services, as well as the harmonization with medical pluralism have potential to improve outcomes and increase equity but their implementation and robust data to monitor their impact pose significant barriers.

A latent class analysis of change and continuity in adolescent health and wellbeing in England during the decline in youth alcohol consumption: A repeat cross-sectional study

In England, the proportion of 13-15 year-olds who have ever drunk alcohol fell from 71% in 1999 to 35% in 2019. Despite substantial research literature studying this decline, we know little about connections with concurrent shifts in wider aspects of health and wellbeing. This paper aims to identify how indicators of health and wellbeing cluster within 15-year-olds in England, identify changes in clustering over time, and explore associations with sex and family affluence. We used latent class analysis of cross-sectional data from the Health Behaviours in School-aged Children study (n = 5,942; four waves 2001/02-2013/14). Classes were defined by indicators of substance use, sexual activity, diet, exercise, school-related measures, e-media use, parental relationships, and wellbeing. We identified three classes, which we labelled Overall unhealthy, Substance abstainers with behavioural risk indicators, and Overall healthy. The probability of being in the Overall unhealthy class fell (2001/02: 0.39; 2013/14: 0.18) while the probability of being in the Overall healthy class increased (0.21 to 0.41). The probability of weekly alcohol use fell in all classes (e.g. Overall unhealthy: 0.71 to 0.28). Females (female vs male OR: 1.74 95%CI: 1.30 - 2.34) and those with low family affluence (high vs low family affluence OR: 0.18 95%CI: 0.08 - 0.44) had significantly higher odds of being in the Overall unhealthy class. Overall, adolescents became more likely to have co-occurring indicators of good health and wellbeing, including reduced alcohol consumption, sexual activity and cigarette smoking. However, girls and those from poorer families remained more likely to have poor health and wellbeing.

An age-period-cohort approach to studying long-term trends in obesity and overweight in England (1992-2019)

OBJECTIVE

This study aims to understand long-term trends in obesity and overweight in England by estimating life-course transitions as well as historical and birth cohort trends for both children and adults.

METHODS

Data on individuals aged 5 to 85 years old from the Health Survey for England were used, covering the period 1992 to 2019 and birth cohorts born between 1909 and 2013. Individual BMI values were classified as healthy weight, overweight, or obesity. Trends were compared, and an age-period-cohort model was estimated using logistic regression and categorical age, period, and cohort groups.

RESULTS

There was significant variation in age trajectories by birth cohorts for healthy weight and obesity prevalence. The odds of having obesity compared with a healthy weight increased consistently with age, increased throughout the study period (but faster between 1992 and 2001), and were higher for birth cohorts born between 1989 and 2008. The odds of having overweight showed an inverted U-shape among children, increased through adulthood, have been stable since 2012, and were considerably higher for the youngest birth cohort (2009-2013).

CONCLUSIONS

Younger generations with higher overweight prevalence coupled with increasing obesity prevalence with age suggest that obesity should remain a high priority for public health policy makers in England.

What influences cancer treatment service access in Ghana? A critical interpretive synthesis

OBJECTIVES

Multiple social-cultural and contextual factors influence access to and acceptance of cancer treatment in Ghana. The aim of this research was to assess existing literature on how these factors interplay and could be susceptible to local and national policy changes.

DESIGN

This study uses a critical interpretive synthesis approach to review qualitative and quantitative evidence about access to adult cancer treatment services in Ghana, applying the socioecological model and candidacy framework.

RESULTS

Our findings highlighted barriers to accessing cancer services within each level of the socioecological model (intrapersonal, interpersonal community, organisational and policy levels), which are dynamic and interacting, for example, community level factors influenced individual perceptions and how they managed financial barriers. Evidence was lacking in relation to determinants of treatment non-acceptance across all cancers and in the most vulnerable societal groups due to methodological limitations.

CONCLUSIONS

Future policy should prioritise multilevel approaches, for example, improving the quality and affordability of medical care while also providing collaboration with traditional and complementary care systems to refer patients. Research should seek to overcome methodological limitations to understand the determinants of accessing treatment in the most vulnerable populations.

BMI trajectories, morbidity, and mortality in England: a two-step approach to estimating consequences of changes in BMI

OBJECTIVE

BMI is known to have an association with morbidities and mortality. Many studies have argued that identifying health risks using single BMI measures has limitations, particularly in older adults, and that changes in BMI can help to identify risks. This study identifies distinct BMI trajectories and their association with the risks of a range of morbidities and mortality.

METHODS

The English Longitudinal Study of Aging provides data on BMI, mortality, and morbidities between 1998 and 2015, sampled from adults over 50 years of age. This study uses a growth-mixture model and discrete-time survival analysis, combined using a two-step approach, which is novel in this setting, to the authors' knowledge.

RESULTS

This study identified four trajectories: "stable overweight," "elevated BMI," "increasing BMI," and "decreasing BMI." No differences in mortality, cancer, or stroke risk were found between these trajectories. BMI trajectories were significantly associated with the risks of diabetes, asthma, arthritis, and heart problems.

CONCLUSIONS

These results emphasize the importance of looking at change in BMI alongside most recent BMI; BMI trajectories should be considered where possible when assessing health risks. The results suggest that established BMI thresholds should not be used in isolation to identify health risks, particularly in older adults.

Estimating the impact of changes in weight and BMI on EQ-5D-3L: a longitudinal analysis of a behavioural group-based weight loss intervention

PURPOSE

To estimate the association between changes in BMI and changes in Health-Related Quality of Life (EQ-5D-3L).

METHODS

The WRAP trial was a multicentre, randomised controlled trial with parallel design and recruited 1267 adults (BMI ≥ 28 kg/m²). Participants were allocated to Brief Intervention, a Commercial weight management Programme (WW, formerly Weight Watchers) for 12 weeks, or the same Programme for 52 weeks. Participants were assessed at 0, 3, 12, 24, and 60 months. We analysed the relationship between BMI and EQ-5D-3L, adjusting for age and comorbidities, using a fixed effects model. Test for attrition, model specification and missing data were conducted. Secondary analyses investigated a non-symmetric gradient for weight loss vs. regain.

RESULTS

A unit increase in BMI was associated with a - 0.011 (95% CI - 0.01546, - 0.00877) change in EQ-5D-3L. A unit change in BMI between periods of observation was associated with - 0.016 017 (95% CI - 0.0077009, - 0.025086) change in EQ-5D-3L. The negative association was reduced during weight loss, as opposed to weight gain, but the difference was not statistically significant.

CONCLUSIONS

We have identified a strong and statistically significant negative relationship between BMI changes and HRQoL. These estimates could be used in economic evaluations of weight loss interventions to inform policymaking.

CLINICAL TRIAL REGISTRATION

This trial was registered with Current Controlled Trials, number ISRCTN82857232.

Mapping the EORTC QLQ-C30 to EQ-5D-3L in patients with breast cancer

Background

The types of outcomes measured collected in clinical studies and those required for cost-effectiveness analysis often differ. Decision makers routinely use quality adjusted life years (QALYs) to compare the benefits and costs of treatments across different diseases and treatments using a common metric. QALYs can be calculated using preference-based measures (PBMs) such as EQ-5D-3L, but clinical studies often focus on objective clinician or laboratory measured outcomes and non-preference-based patient outcomes, such as QLQ-C30. We model the relationship between the generic, preference-based EQ-5D-3L and the cancer specific quality of life questionnaire, QLQ-C30 in patients with breast cancer. This will result in a mapping that allows users to convert QLQ-C30 scores into EQ-5D-3L scores for the purposes of cost-effectiveness analysis or economic evaluation.

Methods

We use data from a randomized trial of 602 patients with HER2-positive advanced breast cancer provided 3766 EQ-5D-3L observations. Direct mapping using adjusted, limited dependent variable mixture models (ALDVMM) is compared to a random effects linear regression and indirect mapping using seemingly unrelated ordered probit models. EQ-5D-3L was estimated as a function of the summary scales of the QLQ-C30 and other patient characteristics.

Results

A four component mixture model outperformed other models in terms of summary fit statistics. A close fit to the observed data was observed across the range of disease severity. Simulated data from the model closely aligned to the original data and showed that mapping did not significantly underestimate uncertainty. In the simulated data, 22.15% were equal to 1 compared to 21.93% in the original data. Variance was 0.0628 in the simulated data versus 0.0693 in the original data. The preferred mapping is provided in Excel and Stata files for the ease of users.

Conclusion

A four component adjusted mixture model provides reliable, non-biased estimates of EQ-5D-3L from the QLQ-C30, to link clinical studies to economic evaluation of health technologies for breast cancer. This work adds to a growing body of literature demonstrating the appropriateness of mixture model based approaches in mapping.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08964-5.

Mapping the FACT-B Instrument to EQ-5D-3L in Patients with Breast Cancer Using Adjusted Limited Dependent Variable Mixture Models versus Response Mapping

BACKGROUND

Preference-based measures of health, such as the three-level EuroQol five-dimensional questionnaire (EQ-5D-3L), are required to calculate quality-adjusted life-years for use in cost-effectiveness analysis, but are often not recorded in clinical studies. In these cases, mapping can be used to estimate preference-based measures.

OBJECTIVES

To model the relationship between the EQ-5D-3L and the Functional Assessment of Cancer Therapy-Breast Cancer (FACT-B) instrument, comparing indirect and direct mapping methods, and the use of FACT-B summary score versus FACT-B subscale scores.

METHODS

We used data from three clinical studies for advanced breast cancer providing 11,958 observations with full information on FACT-B and the EQ-5D-3L. We compared direct mapping using adjusted limited dependent variable mixture models (ALDVMMs) with indirect mapping using seemingly unrelated ordered probit models. The EQ-5D-3L was estimated as a function of FACT-B and other patient-related covariates.

RESULTS

The use of FACT-B subscale scores was better than using the total FACT-B score. A good fit to the observed data was observed across the entire range of disease severity in all models. ALDVMMs outperformed the indirect mapping. The breast cancer-specific scale had a strong influence in predicting the pain/discomfort and self-care dimensions of the EQ-5D-3L.

CONCLUSIONS

This article adds to the growing literature that demonstrates the performance of the ALDVMM method for mapping. Regardless of which model is used, the subscales of FACT-B should be included as independent variables wherever possible. The breast cancer-specific subscale of FACT-B is important in predicting the EQ-5D-3L. This suggests that generic cancer measures should not be used for utility mapping in patients with breast cancer.

Development of Methods for the Mapping of Utilities Using Mixture Models: Mapping the AQLQ-S to the EQ-5D-5L and the HUI3 in Patients with Asthma

BACKGROUND

Studies have shown that methods based on mixture models work well when mapping clinical to preference-based methods.

OBJECTIVES

To develop these methods in different ways and to compare performance in a case study.

METHODS

Data from 856 patients with asthma allowed mapping between the Asthma Quality of Life Questionnaire and both the five-level EuroQol five-dimensional questionnaire (EQ-5D-5L) and the health utilities index mark 3 (HUI3). Adjusted limited dependent variable mixture models and beta-based mixture models were estimated. Optional inclusion of the gap between full health and the next value as well as a mass point at the next feasible value were explored.

RESULTS

In all cases, model specifications formally modeling the gap between full health and the next feasible value were an improvement on those that did not. Mapping to the HUI3 required more components in the mixture models than did mapping to the EQ-5D-5L because of its uneven distribution. The optimal beta-based mixture models mapping to the HUI3 included a probability mass at the utility value adjacent to full health. This is not the case when estimating the EQ-5D-5L, because of the low proportion of observations at this point.

CONCLUSIONS

Beta-based mixture models marginally outperformed adjusted limited dependent variable mixture models with the same number of components in this data set. Nevertheless, they require a larger number of parameters and longer estimation time. Both mixture model types closely fit both EQ-5D-5L and HUI data. Standard mapping approaches typically lead to biased estimates of health gain. The mixture model approaches exhibit no such bias. Both can be used with confidence in applied cost-effectiveness studies. Future mapping studies in other disease areas should consider similar methods.

Optimising perioperative care for hip and knee arthroplasty in South Africa: a Delphi consensus study

Background

A structured approach to perioperative patient management based on an enhanced recovery pathway protocol facilitates early recovery and reduces morbidity in high income countries. However, in low- and middle-income countries (LMICs), the feasibility of implementing enhanced recovery pathways and its influence on patient outcomes is scarcely investigated. To inform similar practice in LMICs for total hip and knee arthroplasty, it is necessary to identify potential factors for inclusion in such a programme, appropriate for LMICs.

Methods

Applying a Delphi method, 33 stakeholders (13 arthroplasty surgeons, 12 anaesthetists and 8 physiotherapists) from 10 state hospitals representing 4 South African provinces identified and prioritised i) risk factors associated with poor outcomes, ii) perioperative interventions to improve outcomes and iii) patient and clinical outcomes necessary to benchmark practice for patients scheduled for primary elective unilateral total hip and knee arthroplasty.

Results

Thirty of the thirty-three stakeholders completed the 3 months Delphi study. The first round yielded i) 36 suggestions to preoperative risk factors, ii) 14 (preoperative), 18 (intraoperative) and 23 (postoperative) suggestions to best practices for perioperative interventions to improve outcomes and iii) 25 suggestions to important postsurgical outcomes. These items were prioritised by the group in the consecutive rounds and consensus was reached for the top ten priorities for each category.

Conclusion

The consensus derived risk factors, perioperative interventions and important outcomes will inform the development of a structured, perioperative multidisciplinary enhanced patient care protocol for total hip and knee arthroplasty. It is anticipated that this study will provide the construct necessary for developing pragmatic enhanced care pathways aimed at improving patient outcomes after arthroplasty in LMICs.

Family lifestyle dynamics and childhood obesity: evidence from the millennium cohort study

Background

The prevalence of childhood obesity has been increasing but the causes are not fully understood. Recent public health interventions and guidance aiming to reduce childhood obesity have focused on the whole family, as opposed to just the child but there remains a lack of empirical evidence examining this relationship.

Methods

Using data from the longitudinal Millennium Cohort Study (MCS), we investigate the dynamic relationship between underlying family lifestyle and childhood obesity during early childhood. The MCS interviewed parents shortly after the birth of their child and follow up interviews were carried out when the child was 3, 5 and 7 years. We use a dynamic latent factor model, an approach that allows us to identify family lifestyle, its evolution over time (in this case between birth and 7 years) and its influence on childhood obesity and other observable outcomes.

Results

We find that family lifestyle is persistent, 87.43% of families which were above the 95th percentile on the lifestyle distribution, remained above the 95th percentile when the child was 7 years old. Family lifestyle has a significant influence on all outcomes in the study, including diet, exercise and parental weight status; family lifestyle accounts for 11.3% of the variation in child weight by age 7 years.

Conclusion

The analysis suggests that interventions should therefore be prolonged and persuasive and target the underlying lifestyle of a family as early as possible during childhood in order to have the greatest cumulative influence. Our results suggest that children from advantaged backgrounds are more likely to be exposed to healthier lifestyles and that this leads to inequalities in the prevalence of obesity. To reduce inequalities in childhood obesity, policy makers should target disadvantaged families and design interventions specifically for these families.

Mortality in the vertebroplasty population

BACKGROUND AND PURPOSE

Vertebroplasty is an effective treatment for painful compression fractures refractory to conservative management. Because there are limited data regarding the survival characteristics of this patient population, we compared the survival of a treated with an untreated vertebral fracture cohort to determine whether vertebroplasty affects mortality rates.

MATERIALS AND METHODS

The survival of a treated cohort, comprising 524 vertebroplasty recipients with refractory osteoporotic vertebral compression fractures, was compared with a separate historical cohort of 589 subjects with fractures not treated by vertebroplasty who were identified from the Rochester Epidemiology Project. Mortality was compared between cohorts by using Cox proportional hazards models adjusting for age, sex, and Charlson indices of comorbidity. Mortality was also correlated with pre-, peri-, and postprocedural clinical metrics (eg, cement volume use, RDQ score, analog pain scales, frequency of narcotic use, and improvement in mobility) within the treated cohort.

RESULTS

Vertebroplasty recipients demonstrated 77% of the survival expected for individuals of similar age, ethnicity, and sex within the US population. Compared with individuals with both symptomatic and asymptomatic untreated vertebral fractures, vertebroplasty recipients retained a 17% greater mortality risk. However, compared with symptomatic untreated vertebral fractures, vertebroplasty recipients had no increased mortality following adjustment for differences in age, sex, and comorbidity (HR, 1.02; 95% CI, 0.82-1.25). In addition, no clinical metrics used to assess the efficacy of vertebroplasty were predictive of survival.

CONCLUSIONS

Vertebroplasty recipients have mortality rates similar to those of individuals with untreated symptomatic fractures but have worse mortality compared with those with asymptomatic vertebral fractures.

Cerebral venous sinus density on noncontrast CT correlates with hematocrit

BACKGROUND AND PURPOSE

A positive correlation between HCT and CT attenuation of intravascular blood has long been assumed but has never been established by using substantial patient numbers and modern CT equipment. The purpose of this study was to determine whether apparent increased attenuation on CT in cerebral venous sinuses can be attributed to hemoconcentration alone and to assess whether sinus thrombosis can be differentiated from hemoconcentrated blood based on attenuation values alone.

MATERIALS AND METHODS

We measured HUs in a region of interest within the confluence of dural venous sinuses in 166 unenhanced head CTs and correlated these data with HCT and HGB values in male and female patients aged 2 to 100 years. We then compared these data with similar measurements in 8 patients with recent venous sinus thrombosis. Two-tailed t test and linear regression analyses were performed to evaluate HGB and HCT between groups and with measured CT attenuation of intravascular blood, respectively.

RESULTS

A statistically significant relationship was noted between both HCT and HGB with CT attenuation. Seven of 8 patients with sinus thrombosis had attenuation values >70, but none of the normal subjects had HUs >70.

CONCLUSIONS

Hemoconcentration correlates with CT attenuation in cerebral venous sinuses. Our findings suggest that comparing the ratio of HUs to HCT may be useful in gauging concern for sinus thrombosis.

A pilot study of the use of pain questionnaires in vertebroplasty research

SUMMARY

Administration of comprehensive outcomes measures in elderly patients presenting for vertebroplasty is considered difficult. We administered a battery of 11 outcomes questionnaires with a total of 82 questions, both in person before vertebroplasty and by telephone after vertebroplasty in 20 consecutive patients (mean age, 74.5 years; 80% women). Initial and follow-up interviews required an average of 17.4 +/- 0.36 minutes (range, 14-21 minutes) and 27.2 +/- 0.73 minutes (range, 16-33 minutes), respectively.

Baseline pain and disability in the Investigational Vertebroplasty Efficacy and Safety Trial

BACKGROUND AND PURPOSE

Multiple case series of vertebroplasty outcomes have been published, though no large, placebo controlled trial has yet been performed. Our aim was to report baseline characteristics for the Investigational Vertebroplasty Efficacy and Safety Trial (INVEST), a randomized blinded controlled study of vertebroplasty.

MATERIALS AND METHODS

We compared baseline demographics, pain scores, and scores on the modified Roland-Morris Disability Scale (RMDS), a back pain-specific metric, between 2 groups. One group included subjects enrolled at the lead INVEST site (n = 27 to date). The second group consisted of eligible patients seen concurrently at the lead INVEST site, who declined enrollment (n = 70). Comparisons were made by using 2-sample t tests.

RESULTS

Mean ages were similar between groups, averaging approximately 74 years among study participants and 77 years among nonenrolled eligible patients (P = .17). Approximately 75% of subjects were female in both groups. RMDS scores of enrolled patients at the lead site (18.0 +/- 4.2) were not statistically different from those of eligible nonenrolled patients at the lead site (18.6 +/- 3.6, P = .49). Pain scores in the enrolled subjects were measured as "average intensity over the prior 24 hours" with mean scores of 7.6 +/- 2.1 among enrolled patients at the lead site. Pain scores in eligible nonenrolled patients were measured as "pain at rest," with mean score of 3.4 +/- 3.3, and "pain with activity," with mean score of 8.5 +/- 2.0.

CONCLUSIONS

Patient demographics among subjects enrolled in the INVEST are similar to those in a cohort of eligible nonenrolled patients. Back pain-specific disability was similar between subjects enrolled in the INVEST study and eligible nonenrolled patients at the lead site.

Efficacy of percutaneous vertebroplasty for multiple synchronous and metachronous vertebral compression fractures

BACKGROUND AND PURPOSE

Limited data exists regarding the efficacy of percutaneous vertebroplasty for multiple synchronous and metachronous vertebral compression fractures. The purpose of this study was to evaluate whether the number of vertebral levels treated during percutaneous vertebroplasty procedures or the number of separate vertebroplasty procedures performed on a given patient affect clinical outcomes.

MATERIALS AND METHODS

We defined 3 patient populations in our retrospective study. Group 1 included 328 patients who underwent 1 single-level vertebroplasty procedure. Group 2 included 226 patients who underwent a single procedure in which 2 or more vertebral levels were treated. Group 3 included 101 patients who underwent 2 or more separate vertebroplasty procedures. Follow-up was performed between 1 week and 2 years postoperatively. Clinical outcomes were assessed through analysis of quantitative measurements of pre- and postoperative levels of pain with and without activity (0-10) as well as mobility improvement. The Kruskal-Wallis rank sum test was used to evaluate the differences among groups. Univariate and chi(2) analyses were performed to show the proportion of underlying diseases in each group.

RESULTS

Mean pain improvement with/without activity at 2-year follow-up was 5.8/3, 4.9/3.7, and 5.4/3.1 in groups 1, 2, and 3, respectively; and mean mobility improvement in 2-year follow-up was 0.67, 0.63, and 0.65 for groups 1, 2, and 3, respectively.

CONCLUSIONS

There was no significant difference in pain relief and mobility improvement in patients treated for multiple synchronous or metachronous vertebral compression fractures in comparison with those treated for solitary isolated fractures.

Urinary tract infections in the potential vertebroplasty patient: incidence, significance, and management

SUMMARY

Percutaneous vertebroplasty has been deferred due to potential complications from urinary tract infections (UTIs). Our aim was to help sort out the types of treatment needed for percutaneous vertebroplasty patients and the length delay for performing the procedure. We searched for information regarding the ramifications of infection from the literature and devised a plan of treatment for the various infectious problems that may occur in patients undergoing percutaneous vertebroplasty. We devised a plan of action for the screening, testing, diagnosis and treatment of patients with a potential UTI who are presenting for a percutaneous vertebroplasty.

Percutaneous vertebroplasty for painful compression fractures in a small cohort of patients with a decreased expectation-related placebo effect due to dementia

BACKGROUND AND PURPOSE

Although abundant literature has reported success with vertebroplasty for the treatment of painful compression fractures, none has accounted for a potential expectation-related placebo effect. We report the results of vertebroplasty for painful vertebral body compression fractures in a small cohort of patients with dementia with the assumption that this patient subgroup is subjected to a decreased placebo effect.

MATERIALS AND METHODS

All patients with objective evidence of dementia (N = 10) who had undergone vertebroplasty at our institution were identified from a comprehensive prospectively constructed vertebroplasty data base. The patients' pain at rest and activity, mobility, and pain-medication use were analyzed at 2 hours postprocedure, 1 week, 1 month, 6 months, and 1 year.

RESULTS

Pain with activity decreased or resolved in 80%-100% of patients at each time point, whereas pain at rest decreased or resolved in 78%-100% of all patients at each time point. Improved mobility was reported in 80%-100% of patients at all time points. Pain medication was decreased or stopped in 67% of patients at 1 week and in 100% of patients at 6 months and 1 year.

CONCLUSION

Treatment of painful compression fractures in patients with dementia demonstrates a high rate of success regarding pain relief and mobility. This study offers additional evidence that vertebroplasty has true benefit.

Significance and targeting of small, central clefts in severe fractures treated with vertebroplasty

We report a small cohort of patients with severe osteoporotic fractures treated with vertebroplasty. We note a high prevalence of small, central, intraosseous clefts in these severe fractures. Rather than filling the small amount of residual bone marrow around the periphery of these severe fractures, as suggested by previous authors, we suggest central needle placement to fill these central clefts.

Vertebroplasty in multiple myeloma: outcomes in a large patient series

BACKGROUND AND PURPOSE

Despite the literature supporting the efficacy of vertebroplasty for treatment of osteoporotic vertebral compression fractures, few reports exist documenting its use in the treatment of compression fractures in multiple myeloma patients. Accordingly, we sought to characterize the imaging characteristics, clinical course, and outcomes in myeloma patients treated with vertebroplasty.

MATERIALS AND METHODS

We performed a retrospective review of clinical outcome data from 67 multiple myeloma patients treated with vertebroplasty since October 2000. Quantitative outcome data including the Roland Morris Disability Questionnaire (RDQ) and Visual Analog Scales for pain and qualitative outcome data (self-reported pain, mobility, and narcotic use) were collected preoperatively, immediately after vertebroplasty, and at 1 week, 1 month, 6 months, and 1 year after treatment.

RESULTS

Significant improvements in all of the outcome measures were observed postoperatively and throughout the duration of follow-up. Quantitative outcome measures (RDQ, analog pain scale 0-10, with rest and activity) improved by 11.0 (48%; P < .0001), 2.7 (25%; P < .001), and 5.3 (48%; P < .0001) points, respectively, with persistent improvement at 1 year (P < .01; P < .03; P < .001). Eighty-two percent and 89% of patients experienced a significant improvement in subjective rest pain and activity pain, respectively. Subjective scores achieved durable improvements, with 65% of patients requiring fewer narcotics after vertebroplasty and 70% having improved mobility.

CONCLUSION

Vertebroplasty provides significant and durable pain relief for patients with intractable spinal pain secondary to compression fractures resulting from multiple myeloma.

Balloon-assisted coiling of intracranial aneurysms: evaluation of local thrombus formation and symptomatic thromboembolic complications

BACKGROUND AND PURPOSE

Remodeling balloons are used to assist in endovascular coiling of aneurysms. We evaluated our experience with balloon-assisted coiling (BAC) in an attempt to determine whether this technique increased the rate of thrombus formation or symptomatic thromboembolic complications.

MATERIALS AND METHODS

In 3 years, we treated 221 patients with intracranial aneurysms. Statistical analysis was performed to assess whether BAC increased the rate of thrombus formation or symptomatic thromboembolic complications. Patient demographics, aneurysm size, location, neck width, antiplatelet therapy, and rupture status were evaluated.

RESULTS

We detected no statistically significant difference in rates of thrombus formation (14% versus 9% with and without BAC, respectively, P=0.35) or symptomatic thromboembolic events (7% versus 5% with and without BAC, respectively, P=0.76), though our power to detect small differences was limited. There was also no correlation with age, sex, rupture status, aneurysm size, or location. There was a significant increase in the rates of thrombus formation (6% versus 16%, P=0.02) and symptomatic thromboembolic complications (3% versus 10%, P=0.04) in aneurysms that were classified as narrow- or wide-necked, respectively. The use of clopidogrel was associated with a decrease in the rate of complications (P=0.01).

CONCLUSION

In this series, we detected no significant increase in the rates of either intraprocedural thrombus formation or symptomatic thromboembolic events in patients treated with BAC. Larger studies are required to confirm our observations. Wide-necked aneurysms were independently associated with increased rates of thrombus formation and symptomatic thromboembolic complications, whereas the use of clopidogrel was protective (P=0.01).

Endovascular treatment of epistaxis in patients with hereditary hemorrhagic telangiectasia

BACKGROUND AND PURPOSE

The treatment of epistaxis in patients with hereditary hemorrhagic telangiectasia can be very challenging. The purpose of our study was to evaluate our experience with endovascular epistaxis embolization in patients with hemorrhagic hereditary telangiectasia and to compare this with our experience in patients treated for idiopathic epistaxis.

MATERIALS AND METHODS

Over a 6-year period, we treated 22 patients with epistaxis by using endovascular embolization. Twelve of 22 patients had hereditary hemorrhagic telangiectasia; 10 patients had idiopathic epistaxis. The angiographic findings, efficacy of treatment, and complications for both groups were compared.

RESULTS

Patients with hereditary hemorrhagic telangiectasia had angiographic abnormalities in 92% of cases compared with only 30% in the idiopathic epistaxis group. Compared with a group of 10 patients treated for other causes of epistaxis, those with hereditary hemorrhagic telangiectasia required significantly more re-embolization treatments or additional surgical procedures because of continued or recurrent bleeding episodes after embolization (P=.03). Complications were rare; a single patient in the idiopathic epistaxis group had a self-limited groin hematoma and postembolization facial pain.

CONCLUSION

Endovascular embolization of epistaxis is a safe procedure that can be useful for patients with severe acute epistaxis or chronic persistent bleeding. Patients who undergo endovascular embolization for epistaxis related to hereditary hemorrhagic telangiectasia require repeat embolization and subsequent surgical procedures more often than those with idiopathic epistaxis.

In vitro antiproliferative activity of the farnesyltransferase inhibitor R115777 in hematopoietic progenitors from patients with myelofibrosis with myeloid metaplasia

R115777 is an orally bioavailable farnesyltransferase inhibitor (FTI) that has displayed encouraging activity in patients with acute myeloid leukemia. To determine whether R115777 might exert similar activity in myelofibrosis with myeloid metaplasia (MMM), we evaluated its effects on circulating myeloid progenitor cells from patients with MMM (n=25) using in vitro colony-forming assays. The median R115777 concentrations that inhibited colony formation by 50% were 34 and 2.7 nM for myeloid and megakaryocytic colonies from MMM patients, respectively. Progenitors from normal controls and patients with other myeloproliferative disorders demonstrated similar sensitivity. Since the ras polypeptides are one putative target of FTIs, the potential role of ras effectors was examined by incubating parallel progenitor assays with the phosphatidyl-inositol-3 (PI-3) kinase inhibitor LY294002 and the mitogen-activated protein kinase 1 inhibitor PD98059. MMM progenitor colonies (n=7) were highly sensitive to LY294002 but not to PD98059, implying that the PI-3 kinase pathway may be critical for survival and proliferation of these cells. In addition to indicating that MMM progenitors are sensitive to clinically achievable R115777 concentrations in vitro, these results provide a potential explanation for the thrombocytopenia observed with R115777 during the treatment of other hematologic malignancies.

Blood lactic acid levels after artificial heart implantation

The aim of this study is to investigate blood lactic acid levels after the placement of the AbioCor implantable replacement heart to determine whether circulatory support with the AbioCor device results in adequate tissue perfusion. Tissue perfusion may not be adequate during cardiac surgery, especially with the use of cardiopulmonary bypass (CPB). Inadequate perfusion is usually associated with anaerobic metabolism, metabolic acidosis, and lactate accumulation. Ten calves had implantation of the AbioCor by means of a right thoracotomy. Standard cardiopulmonary bypass was performed during surgery. Lactic acid levels and blood gas analyses were measured. All animals were monitored for pressures in the aorta, pulmonary artery, and left and right atria. The output of the AbioCor was calculated based on beat rate and stroke volume. All animals were rapidly weaned off cardiopulmonary bypass to full AbioCor support and had normal hemodynamics with normal filling pressures. The lactic acid levels were elevated after surgery, peaked at 8 to 12 hours, and then gradually decreased to the normal range 24 hours after surgery. There was a positive relationship between lactate levels, oxygen consumption, and extraction rate, that is, the lactic acid levels were higher in the presence of increased oxygen consumption and increased oxygen extraction rate. There was a negative relationship between lactate levels and oxygen delivery, and arterial and venous oxygen content, that is, the lactic acid levels were higher when oxygen delivery and arterial and venous oxygen contents were low. The pathophysiology of lactic acidosis is uncertain, but is most likely due to inadequate perfusion during cardiopulmonary bypass, and lactate washout after adequate perfusion has been established. The return to aerobic metabolism with clearance of lactate demonstrates that the AbioCor is able to provide complete circulatory support with normal tissue perfusion.

A phase II trial of pirfenidone (5-methyl-1-phenyl-2-[1H]-pyridone), a novel anti-fibrosing agent, in myelofibrosis with myeloid metaplasia

The anti-fibrotic and cytokine modulatory properties of pirfenidone suggest its usefulness in the treatment of myelofibrosis with myeloid metaplasia (MMM). In a prospective study, 28 patients with MMM were treated with oral pirfenidone. Twelve patients completed 1 year of therapy; 13 were withdrawn because of disease progression and three because of drug intolerance. Only one patient experienced a clinically relevant benefit with respect to anaemia and splenomegaly. The overall lack of clinical benefit correlated with no significant improvement in the bone marrow morphological features of the disease. We conclude that pirfenidone has no significant clinical or biological activity in MMM.

Current status of the AbioCor implantable replacement heart

BACKGROUND

The AbioCor implantable replacement heart (IRH) has been developed as an alternative to transplant (ie, destination therapy). We report our experience with the AbioCor IRH in a bovine model at the University of Louisville.

METHODS

Male Holstein cows were used (85 to 115 kg). The internal controller, battery, and secondary transcutaneous energy transfer coil were implanted in the right flank. After cardiopulmonary bypass, the thoracic unit was implanted orthotopically. After removal of air and weaning from cardiopulmonary bypass, the AbioCor was connected to internal components and energy transfer through transcutaneous energy transfer coils was achieved.

RESULTS

Nineteen animals underwent implantation of the AbioCor IRH for a proposed 30-day duration. There were 6 deaths, none related to device malfunction. All animals demonstrated normal hemodynamics with normal pressures in the aorta, pulmonary artery, left atrium, and right atrium. There was no significant hemolysis and all animals demonstrated normal end organ function. The internal battery allowed for brief periods of untethered mobility.

CONCLUSIONS

The AbioCor IRH has resulted in normal hemodynamics and normal end organ function without evidence of hemolysis in a bovine model.

Intermediate-term results after partial left ventriculectomy for end-stage dilated cardiomyopathy: is there a survival benefit?

BACKGROUND

The mortality of congestive heart failure remains high despite advances in medical therapy. Partial left ventriculectomy (PLV) has been advocated as a surgical alternative for select patients with dilated cardiomyopathy.

METHODS

A prospective clinical trial of PLV for patients with end-stage idiopathic dilated cardiomyopathy was performed. Inclusion criteria were left ventricular end-diastolic diameter (LVEDD) greater than 7 cm, refractory New York Heart Association (NYHA) Class IV symptoms, and severely depressed exercise oxygen consumption.

RESULTS

Twenty patients underwent PLV with mean follow-up of 21.1 months. Sixteen were male; mean age was 50.1 years +/- 12.0 years (range 25-67 years). Left ventricle (LV) ejection fraction improved after surgery from 14.1% +/- 4.7% to 24.1% +/- 3.1% (p < 0.05, t-test) and this improvement persisted up to 3 years after operation. LVEDD and NYHA Class also were notably improved. There were two early deaths for an operative mortality of 10% (2 of 20 patients). Nine patients after initial improvement in clinical status and LV function developed worsening congestive heart failure (CHF). Six of the 9 ultimately died of complications secondary to CHF. One-, 2-, and 3-year survival rates were 84%, 64%, and 40%, respectively, by Kaplan-Meier analysis. The other three patients required listing for transplantation because of recurrent NYHA Class IV symptoms. Freedom from death or the need for listing for transplantation at 1, 2, and 3 years was 65%, 53%, and 33%, respectively. The remaining nine patients all had improvement in their NYHA classification.

CONCLUSIONS

PLV can be performed with acceptable early and intermediate term mortality; survival compares favorably to reports of similar groups of patients treated with medical therapy alone.

Radiation therapy for symptomatic hepatomegaly in myelofibrosis with myeloid metaplasia

OBJECTIVE

To describe the experience with liver irradiation in advanced cases of myelofibrosis with myeloid metaplasia (MMM).

METHODS

Over a 20-yr period, 14 patients with MMM were treated with a total of 25 courses of liver, abdominal, or abdominal and pelvic irradiation for symptomatic hepatomegaly with (5 patients) or without (9 patients) ascites. All 14 patients had advanced disease and 11 (79%) had previous splenectomy. The median radiation therapy (RT) dose per course was 150 cGy (range 50-1000) administered at a median of six fractions. Four patients received two to six courses.

RESULTS

Twelve of the 14 patients (86%) had a transient (median 3 months) subjective response from RT. However, in only 35% of these was there a transient (median 3 months) decrease in palpable liver size. Four of the five patients with ascites experienced a short-term response from RT. Eight of the 13 patients suitable for evaluation (62%) had treatment-associated cytopenia, often in the form of anemia and/or thrombocytopenia. At last follow-up, 10 patients (71%) had died after a median of 7 months (range 0.1-23) and 4 were alive at 3, 20, 33, and 57 months after RT.

CONCLUSIONS

Low-dose abdominal RT for symptomatic hepatomegaly or ascites associated with advanced-stage MMM is myelosuppressive and provides only temporary and mainly subjective and short-lived relief.

Can a linear electrical analog model of a mechanical valve predict flow by using a pressure gradient?

The objective was to determine whether a previously developed technique for biological aortic valves could predict flow through a mechanical valve. An electrical analog model of the aortic valve that includes compliance, resistance, and inertance parameters, and corresponding second order differential equations was used to predict flow given a pressure gradient, as previously reported. Simulated pressures and flow were recorded by using a pulse duplicator system. The heart rate was varied from 60 to 180 bpm, and the stroke volume was varied from 22 to 67 cc. Resistance, inertance, and compliance parameters of the governing differential equation were estimated by using a least-squares fit to the measured flow at 120 bpm and 50 cc stroke volume. By using these parameter estimates, flow was calculated for other heart rates and stroke volumes. To achieve a better flow prediction, a nonlinear filter (third order polynomial range calibration equation) was applied to the output of the linear model (flow). The mean error, full-scale error, and spectral error in magnitude and phase between measured and predicted flow were compared. Error in mean flow ranged from 3% at medium flow rates to 90% at low flow rates. The maximum and minimum full scale errors were 12% and 5%, respectively. Error in the harmonics of measured and calculated flow ranged from 0% to 55%. Larger errors were usually present at the higher harmonics. The agreement between measured and calculated flow was better at normal and high flows but rather poor at low flows. The nonlinear filter (range calibration equation) was unable to account for the discrepancies between the measured and calculated flow over all flow ranges. It seems that this linear model and nonlinear filter have limited application, and an alternate nonlinear approach may produce better results.

Initial experience with the AbioCor implantable replacement heart at the University of Louisville

Potential benefits of heart transplantation are limited by the severe donor organ shortage. The AbioCor implantable replacement heart has been developed as a potential alternative to heart transplantation. We report our initial experience with the AbioCor in a bovine model. A right thoracotomy was performed for access to the heart and great vessels. After initiation of cardiopulmonary bypass, excision of the native ventricles was followed by orthotopic placement of the IRH and complete implantation of the transcutaneous energy transfer coil, controller, and battery pack. Invasive monitoring of IVC, SVC, carotid artery, pulmonary artery, and left atrial (LA) pressures was performed in all animals. Twelve calves have undergone implantation of the AbioCor. There were three early deaths, one from bleeding, one from respiratory failure, and one from neurodysfunction from low flow during CPB. Nine animals have had a normal recovery and survived a mean of 24.5 days (range, 4-48 days). All the animals have demonstrated excellent hemodynamics with the maintenance of normal pressures in the LA, SVC, IVC, pulmonary artery, and aorta. Adjustment of the right-sided internal hydraulic fluid shunt has allowed for control of right-left balance and, thereby, manipulation of left and right side filling pressures. Late morbidity has consisted of neck wound infection and sepsis, pneumonia, and bleeding. Successful orthotopic implantation of all components of the AbioCor has been achieved in a bovine model. This device has demonstrated restoration of normal hemodynamics and excellent function of the atrial hydraulic shunt to achieve right-left balance.

Fructose-1,6-diphosphate and a glucose-free solution enhances functional recovery in hypothermic heart preservation

BACKGROUND

Fructose-1,6-diphosphate (FDP) has been shown to protect tissue during hypoxia under various ischemic conditions, including isolated heart perfusion. We tested the hypothesis that adding FDP to St. Thomas solution can extend hypothermic heart preservation time.

METHODS

Sixteen adult Sprague-Dawley rats were used. Under general anesthesia, the hearts were removed and preserved at 4 degrees C in St. Thomas solution (30 ml/kg) for 12 hours. FDP (5 mM) was added to the St. Thomas solution in the study group (n = 8), whereas no FDP was used in the control group (n = 10). The hearts were reperfused after 12 hours of preservation using a working heart model.

RESULTS

In the study group, cardiac output ranged from 13.00 +/- 2.34 to 17.66 +/- 1.71 ml/min, maximum aortic flow was 3.40 +/- 1.99 to 9.26 +/- 1.72 ml/min, left ventricular stroke volume ranged from 0.074 +/- 0.014 to 0.092 +/- 0.009 ml, left ventricular stroke work ranged from 6.22 +/- 0.39 to 7.95 +/- 0.44 ml/mmHg, and maximum left ventricular generated power was 14.38 +/- 2.94 to 20.16 +/- 2.49 Joules/min. All of these parameters were higher than those in the control group (p < 0.001). Coronary vascular resistance and myocardial tissue wet/dry weight ratio were lower in the study group than in the control group (p < 0.05).

CONCLUSIONS

Heart function was better preserved when FDP was added to St. Thomas solution during hypothermic rat heart preservation. The mechanism is not totally clear, but enhancement of high-energy phosphate production during ischemia is possible. Key words: heart, procurement, hypothermia, fructose-1,6-diphosphate.

Two step cardiomyoplasty with vascular delay: effect of stimulation of latissimus dorsi muscle on diastolic function

A common concern in cardiomyoplasty is whether latissimus dorsi muscle (LDM) stimulation impairs diastolic function. This study determined the time course of left ventricular (LV) contraction and relaxation and their relationship to the diastolic function. Ten mongrel dogs underwent vascular delay of the left latissimus dorsi muscle 2 weeks before cardiomyoplasty. Fourteen to 18 days later, the effects of LDM stimulation were evaluated. Our study demonstrated that LDM stimulation significantly increased peak LV systolic pressure (131.3 +/- 7.5 to 152.0 +/- 7.5* mm Hg), +dP/dt (1585 +/- 151 to 2088 +/- 176 x mm Hg/s), stroke volume (10.8 +/- 1.5 to 13.8 +/- 1.9* ml), stroke work (17.2 +/- 2.7 to 25.6 +/- 3.8* gm x m), and peak aortic flow (4751 +/- 698 to 6712 +/- 926* ml/min), and significantly decreased the pre-ejection time (113.9 +/- 12.6 to 92.3 +/- 7.8* ms) and total systolic time (366.0 +/- 26.9 to 333.6 +/- 21.3* ms) (*p < 0.05). As for diastolic function, LDM stimulation decreased -dP/dt (-1462 +/- 116 to -1781 +/-116* mm Hg/s) and tau (64.0 +/- 6.1 to 52.1 +/- 2.9* ms). The diastolic filling time (Tdf) was significantly longer (177.9 +/- 17.6 to 213.7 +/- 18.7* ms) during the beat immediately after LDM stimulation. These changes reflected an overall stronger contraction and faster relaxation. Our results imply that with vascular delay, stimulation of LDM not only assists systolic function but also improves diastolic function in cardiomyoplasty.

Results after partial left ventriculectomy versus heart transplantation for idiopathic cardiomyopathy

OBJECTIVE

Partial left ventriculectomy has been introduced as an alternative surgical therapy to heart transplantation. We performed a single-center, retrospective analysis of all patients with idiopathic dilated cardiomyopathy who underwent partial left ventriculectomy or heart transplantation or who were listed for transplantation to determine operative mortality rate, 12-month survival, freedom from death on the heart transplantation waiting list, and freedom from death or need for relisting for heart transplantation.

METHODS

Patients who had partial left ventriculectomy (October 1996 to April 1998) were retrospectively compared with patients who were listed for heart transplantation (January 1995 to April 1998). Survival was assessed after the surgical procedure (partial left ventriculectomy vs heart transplantation) and from time of listing for heart transplantation to assess the additional impact of waiting list deaths. Freedom from death or relisting for heart transplantation was also compared.

RESULTS

There was no difference in age or United Network for Organ Sharing status between the 2 groups. Twenty-nine patients with idiopathic dilated cardiomyopathy were listed for heart transplantation; 17 patients underwent transplantation, 6 patients died while on the waiting list, and 6 patients remain listed. One patient died after heart transplantation, and 1 patient required relisting. Sixteen patients had partial left ventriculectomy; 10 patients are in improved condition, 2 patients died (1 death early from sepsis and 1 death from progressive heart failure), and 4 patients required relisting for heart transplantation. Operative survival was 94% after partial left ventriculectomy and 94% after heart transplantation (P =.92). Postoperative 12-month Kaplan-Meier survival was 86% after partial left ventriculectomy and 93% after heart transplantation (P =.90). Twelve-month Kaplan-Meier survival after listing for heart transplantation was 75% due to death while on the waiting list (P =.76). Freedom from death or need for relisting for heart transplantation was 56% after partial left ventriculectomy and 86% after transplantation (P =.063).

CONCLUSION

Operative and 12-month survival after partial left ventriculectomy and heart transplantation were comparable. However, despite their initial improvement, many patients who underwent partial left ventriculectomy required relisting for transplantation. Although partial left ventriculectomy is associated with acceptable operative and 12-month survival, it may prove to serve better as a bridge to transplantation in patients with idiopathic dilated cardiomyopathy rather than definitive therapy, given the number of patients who required relisting for transplantation.

Intermediate-term results of partial left ventriculectomy

Partial left ventriculectomy (PLV) has been introduced as an option for patients with end-stage dilated cardiomyopathy. We report the result of a prospective trial of PLV in patients with idiopathic dilated cardiomyopathy, left ventricular end-diastolic diameter (LVEDD) > 7 cm, refractory New York Heart Association (NYHA) Class IV symptoms, and depressed exercise oxygen consumption studies. Sixteen patients underwent a PLV with a mean follow-up of 13 months. Fourteen patients were male. Mean age was 49.6+/-10.5 years (range 30 to 67 years). Left ventricular ejection fraction (LVEF) improved after surgery from 13.9+/-5.6 to 21.0+/-8.4, and this improvement persisted for up to 12 months after operation. LVEDD and NYHA Class also were significantly improved after surgery and for up to 12 months of follow-up. Operative mortality was 6.25%. Twelve-month survival was 86% by Kaplan-Meier analysis. Four (25%) of 16 patients that had initial improvement after PLV developed recurrent heart failure and were listed for transplantation. Freedom from need for listing for heart transplantation was 65% at 12 months. Freedom from death or the need for relisting at 12 months was 56%. PLV can be performed with acceptable early and 12-month mortality. Significant improvements in LVEF, LVEDD, and NYHA Class are seen at up to 12 months of follow-up. Some patients will develop recurrent heart failure and require relisting for heart transplantation.

Electric analog model of the aortic valve for calculation of continuous beat-to-beat aortic flow using a pressure gradient

The objective was to develop a technique for calculating continuous, beat-to-beat aortic flow (AoF) using only left ventricular pressure (LVP) and aortic pressure (AoP). An electric analog model of the aortic valve was developed that includes resistance (R), inertance (L), and compliance (C) parameters, and resulting second order differential equations were derived. Aortic flow, AoP, and LVP recorded in eight subjects during a 5 day period and during lower body negative pressure (LBNP) were used to validate the model. Resistance, L, and C were estimated using a least-squares fit to the measured AoF on day 0 and during 0 mm Hg LBNP. For days 1-4, AoF was calculated using measured values of AoP and LVP and the R, L, and C values from day 0. Similarly, for LBNP, AoF was calculated using measured values of AoP and LVP, and the R, L, and C values from 0 mm Hg LBNP. The calculated and measured AoF were compared. Differences in cardiac output between the calculated and measured flows were less than 13.1+/-17% across days and under minor altered physiologic conditions (LBNP). Waveform morphology for the calculated AoF also agreed well with the measured AoF. Spectral analysis showed differences in magnitude and phase between measured and calculated aortic flow for the first five harmonics across days, less than 20+/-6% and 25+/-14 degrees, respectively. Preliminary evaluation indicates that our model works well for calculating flow through a biologic valve using LVP and AoP. We speculate that it may perform better for a mechanical valve, and if so it may be possible to develop an instrumented mechanical valve capable of continuous LVP, AOP, and AoF measurements.

Acute cardiovascular changes of partial left ventriculectomy without mitral valve repair

We assessed the acute cardiovascular changes of partial left ventriculectomy (PLV) in a patient with idiopathic dilated cardiomyopathy (IDCM) without mitral regurgitation. Acutely, PLV reduced left ventricular (LV) end-diastolic dimension and volume while increasing LV ejection fraction and cardiac output due to increased HR and SV. Substantial increases in LV filling pressure, possibly due to high LV end-systolic and diastolic elastances, were of concern clinically and the mechanism(s) of change remain unclear. However, one year follow-up showed remarkable improvements in NYHA and VO2 max while maintaining reduced LV volume, increased LVEF, and trivial MR.

Nigerian university students' knowledge, perceptions, and behaviours about HIV/AIDS: are these students at risk?

The purpose of the study was to determine the knowledge level of undergraduate students of a Nigerian university about HIV/AIDS, their perception of risk of contracting HIV/AIDS based on their sexual behaviour, and to assess how students acquire information about HIV/AIDS. The sample consisted of 380 students from five faculties of the university who volunteered to participate in the study. Participants completed a survey asking about their knowledge about transmission, symptomatology and prevention of HIV/AIDS. The survey included questions about their sexual orientation, past and present sexual practices as well as sources of information about HIV/AIDS. The results indicated that the students were knowledgeable about transmission and symptomatology but there were some misconceptions about the mode of transmission of HIV. Few students identified themselves to be at high risk even though majority of them (92%) were sexually experienced. The study also showed that even though these students are knowledgeable and concerned about contracting HIV/AIDS from their partners, this did not prevent them from engaging in unprotected sexual intercourse. It appears, however, that students are exercising caution when negotiating new sexual relationships, as they are likely to discuss (and insist on) using condoms and ask to have a monogamous relationship. Students obtained information about HIV/AIDS primarily from the media rather than from school classrooms and homes, which suggests a need to increase educational efforts at the university. Many students of this university may be at risk of becoming HIV-infected due to their age bracket, level of sexual activity and past/present sexual behaviors. University faculty can be actively involved in developing and implementing HIV/AIDS education and prevention strategies on their campuses. Health educators must go beyond providing accurate and gender-specific information about HIV/AIDS; they must also help students realistically assess their own risk of infection, and develop communication processes which enable them to negotiate safer sexual practices.

Results of partial left ventriculectomy in patients with end-stage idiopathic dilated cardiomyopathy

BACKGROUND

Partial left ventriculectomy has been recently introduced as a surgical therapy for end-stage heart failure. We performed a prospective study of partial left ventriculectomy in patients with end-stage idiopathic dilated cardiomyopathy (IDCM).

METHODS

Patients considered as candidates for partial left ventriculectomy had IDCM, left ventricular end-diastolic diameter greater than 7 cm (LVEDD), refractory New York Heart Association class IV symptoms (NYHA), and severely impaired exercise oxygen consumption. All patients underwent a complete heart transplantation evaluation.

RESULTS

Partial left ventriculectomy was performed in 16 patients with a mean follow-up of 11.1 months. Fourteen patients were male with a mean age of 49.6+/-10.5 years. After surgery there were significant changes in NYHA class, left ventricular ejection fraction, LVEDD, and degree of mitral regurgitation at up to 12 months follow-up. The operative mortality rate was 6.25% and 12-month Kaplan-Meier was 86%. Twelve-month freedom from need for listing for orthotopic heart transplantation was 65%.

CONCLUSION

Partial left ventriculectomy can be performed in patients with idiopathic cardiomyopathy with acceptable operative and 12 month survival rates. Significant improvements are seen in ejection fraction, LVEDD, and NYHA class at 12 month follow up. Late failures do occur and some patients have required relisting for transplant after partial left ventriculectomy.

Clinical experience with the video-assisted saphenectomy procedure for coronary bypass operations

BACKGROUND

Leg wound complications after saphenectomy are frequent after coronary bypass operations and have a detrimental effect on postoperative quality of life and treatment cost. To reduce morbidity, we evaluated a new technique of video-assisted vein harvest.

METHODS

Between March 1996 and October 1996, 50 patients had video-assisted saphenectomy (VAS) and 40 patients had the standard open technique (control group). An additional 13 patients had both procedures (hybrid group). Level of pain, edema, and wound complications were evaluated at discharge and at 2, 4, and 6 weeks postoperatively.

RESULTS

The mean operating time for VAS patients was slightly higher than for control (60.6+/-24.7 minutes versus 53.2+/-21.1 minutes; p > 0.05). The average incision length in VAS patients was 13.8+/-8.8 cm for an average of 3.3 grafts per patient. Three VAS procedures were aborted, two because of time constraints, and one because of bleeding, and a segment of vein was lost to injury. The VAS group had considerably less early postoperative pain than the control group (1.7+/-1.2 versus 4.1+/-1.4 [1 = mild, 10 = severe]; p < 0.005) and edema was similar for both groups. Patients in the hybrid group reported less pain in the VAS-operated leg. Serious wound infection occurred in 4 patients, with 2 patients in the control group requiring reoperation for drainage and flap reconstruction.

CONCLUSIONS

Based on this initial experience, VAS harvesting, although initially more time consuming, is a rapidly mastered technique, results in shorter overall incision length, and is associated with considerably less postoperative pain than the standard open technique.

Role of graft flow measurement technique in anastomotic quality assessment in minimally invasive CABG

BACKGROUND

Anastomotic quality is currently the critical issue in minimally invasive coronary surgery. Although little is known about its effectiveness, surgeons routinely assess grafts intraoperatively using flow probes. This study was designed to determine whether mean flow and the pattern of flow tracing in internal mammary artery grafts obtained with a transit-time flow probe are reliable indicators of anastomotic quality.

METHODS

Mongrel dogs (n = 14, 30 to 35 kg) underwent off-pump left, right, or left and right internal mammary artery to left anterior descending artery anastomosis (23 grafts). Moderate to severe degrees of stenosis were created at the anastomosis by an additional suture. Internal mammary artery graft flow was measured before and after the stenosis was created with the left anterior descending artery occluded. Angiography was performed at random postoperatively to validate the degree of stenosis. Mean flow and flow tracing morphology were compared under various degrees of stenosis.

RESULTS

There were no significant differences in mean graft flow or the morphology of the flow tracing between patent (<15%), mild (<25%), moderate (<50%), and moderately severe (<75%) stenosis. However, mean graft flow decreased (p < 0.05) with severe stenosis (>75%).

CONCLUSIONS

Although differences in mean graft flow and graft flow morphology were detectable in anastomoses with severe stenosis (>75%), they were indistinguishable in anastomoses with mild (<25%) to moderately severe (<75%) stenosis. Flow measurement techniques are valuable tools intraoperatively, but surgeons should exercise caution in their interpretation.

Double grafting of the left anterior descending artery: is the distance between the internal mammary artery and supplemental vein graft anastomoses relevant in graft survival?

INTRODUCTION

Under certain conditions (small internal mammary artery (IMA) or large runoff), double grafting of the left anterior descending (LAD) artery system is necessary to avoid the ominous consequences of myocardial hypoperfusion. Previous studies have shown that a saphenous vein (SVG) adjacent to an IMA graft leads to failure of the IMA. This study compares IMA flow patterns when adjacent ( < 1 cm) and separated (3-4 cm) from a SVG placed on a proximally occluded LAD.

METHODS

A SVG and right IMA (PIMA) to proximal LAD (2.5-3 mm) coronary bypass were performed in 12 mongrel dogs. The left IMA (DIMA) was anastomosed to the distal LAD (1.5 mm). All anastomoses were carried out without cardiopulmonary bypass. The native LAD was occluded proximally to the PIMA anastomosis, and all graft flows were measured in competitive and non-competitive flow conditions.

RESULTS

Isolated graft to LAD flows were similar for the three conduits. There was a drop in flow in both the PIMA and DIMA when placed in competition with the SVG (10.1+/-3.0 vs. 19.1+/-4.6 ml/min; P < 0.05). The total drop in flow was significantly greater in the PIMA (67.6 vs. 39.9%; P < 0.05). Diastolic flow was better preserved in the distal IMA graft (19.6 + 5.6 vs. 10.2+/-3.0 ml/min; P < 0.05). The patterns of flow were much different during competition and there was significant retrograde systolic flow in all PIMA grafts while there was no (n = 5) or minimal retrograde flow (n = 7) in the DIMA grafts.

CONCLUSION

An IMA graft, when adjacent to a SVG, sustains a significant decrease in both total and diastolic flows and develops an oscillating pattern of flow in early systole (retrograde then antegrade). Placing the IMA more distally on the LAD improves flow and decreases retrograde flow. In clinical situations requiring double grafting on the LAD, distance between grafts may be an important factor in maintaining IMA patency.

Evolution of forelimb movement patterns for prey manipulation in anurans

Unlike other amphibians, frogs often use their forelimbs to capture and transport prey. In the present study, high-speed videography was used to observe forelimb use during feeding in a diverse group of anurans in order to determine the evolution of forelimb movement patterns among anuran taxa. Data were gathered from 488 individuals representing 104 species, 55 genera, and 16 families. Five distinct behavior patterns were identified: scooping entails using the back of the hand to push prey into the mouth; wiping involves the use of the palm of the hand to push prey, protruding laterally from the mouth, toward the midline; during prey stretching, one end of the prey is held in a stationary position by the hands while the other end is pulled upward by the jaws; in grasping, the palms face the midline or the substrate as the fingers are wrapped around the prey; grasping with wrist rotation is similar to grasping, but the wrists rotate inward as the hands grasp the prey so that the palms face the mouth. The distribution of these behavior patterns was mapped onto the most recent phylogenetic hypothesis for anurans. Maximum parsimony analyses suggest that scooping and wiping are primitive and have been retained by many frog lineages. Wiping was not observed in the pipids, which are the only anurans that lack tongues and use hydraulic transport. Prey stretching appears to have evolved several times in unrelated taxa. Grasping and grasping with wrist rotation appear to have evolved only in arboreal groups, suggesting that the ability to climb is a preadaptation for the ability to grasp prey. Several species were observed using grasping motions in place of the tongue to capture prey.

Preoperative and postoperative comparison of patients with univentricular and biventricular support with the thoratec ventricular assist device as a bridge to cardiac transplantation

OBJECTIVES

The goal of this study was to determine whether there are differences in populations of patients with heart failure who require univentricular or biventricular circulatory support.

METHODS

Two hundred thirteen patients who were in imminent risk of dying before donor heart procurement and who received Thoratec left (LVAD) and right (RVAD) ventricular assist devices at 35 hospitals were divided into three groups: group 1 (n = 74), patients adequately supported with isolated LVADs; group 2 (n = 37), patients initially receiving an LVAD and later requiring an RVAD; and group 3 (n = 102), patients who received biventricular assistance (BiVAD) from the beginning.

RESULTS

There were no significant differences in any preoperative factors between the two BiVAD groups. In the combined BiVAD groups, pre-VAD cardiac index (BiVAD, 1.4 +/- 0.6 L/min per square meter, vs LVAD, 1.6 +/- 0.6 L/min per square meter) and pulmonary capillary wedge pressure (BiVAD, 27 +/- 8 mm Hg, vs LVAD, 30 +/- 8 mm Hg) were significantly lower than those in the LVAD group, and pre-VAD creatinine levels were significantly higher (BiVAD, 1.9 +/- 1.1 mg/dl, vs LVAD, 1.4 +/- 0.6 mg/dl). In addition, greater proportions of patients in the BiVAD groups required mechanical ventilation before VAD placement (60% vs 35%) and were implanted under emergency conditions than in the LVAD group (22% vs 9%). The survival of patients through heart transplantation was significantly better in patients who had an LVAD (74%) than in those who had BiVADs (58%). However, there were no significant differences in posttransplantation survival through hospital discharge (LVAD, 89%; BiVAD, 81%).

CONCLUSION

Patients who received LVADs were less severely ill before the operation and consequently were more likely to survive after the operation. As the severity of illness increases, patients are more likely to require biventricular support.

Electrodiagnostic evidence for cervical radiculopathy and suprascapular neuropathy in shoulder pain

Patients diagnosed with a shoulder impingement syndrome occasionally do not respond to techniques used for treatment of soft tissue injury. The neurologic examination may be only partially abnormal or incomplete due to pain limitation so that peripheral nerve or nerve root abnormalities are overlooked. This study was undertaken to investigate the frequency of cervical radiculopathy and suprascapular neuropathy in patients with shoulder pain who were initially diagnosed with a musculoskeletal syndrome. Thirty-three subjects with a diagnosis of unilateral or bilateral impingement syndrome were entered into the study. A neurological examination was performed, followed by electromyography on 38 upper extremities and associated cervical paraspinal muscles to search for electrodiagnostic evidence for a suprascapular neuropathy and/or cervical radiculopathy. There were no subjects with electrodiagnostic evidence for suprascapular neuropathy. In two studies (5.3%), there was electrodiagnostic evidence for a C5/6 radiculopathy, and in nine (23.7%) additional subjects, there was electrodiagnostic evidence for a possible cervical radiculopathy. The remaining 27 (71.1%) studies showed no significant electrodiagnostic evidence for a cervical radiculopathy. Of the 11 subjects with abnormal electrodiagnostic studies, the neurological examination in 7 (63.6%) was normal except for pain-limited manual muscle testing, and the other 4 (36.4%) had an abnormality in either sensation testing, muscle bulk, or muscle stretch reflexes. One case of a patient with an initial diagnosis of soft tissue injury is presented. In patients undergoing evaluation for shoulder pain, cervical radiculopathy as a possible etiology should be considered, even when there is an equivocal clinical examination.