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Biomedical subjects

D A Gould

Publications and source records attributed to D A Gould.

At least 19 recordsLinked to original sources
PubMed2006

Simulators in catheter-based interventional radiology: training or computer games?

Training in interventional radiology (IR) relies on a traditional apprenticeship; to protect patients, expert supervision is mandatory until knowledge, attitudes and practical skills have been certified as satisfactory. However, the current quality of IR training is threatened by reduced time for trainees to learn, as well as a loss of basic diagnostic, training cases to non-invasive imaging. At the same time, IR techniques are becoming a focus of interest to a range of other clinical specialities. To address this training shortfall there is a need to develop novel training alternatives such as simulator models. Few simulator models in any medical field have been successfully validated to show improved clinical skills in treating patients. To date no endovascular simulator has met this standard. A good simulator must be based around key performance measures (metrics) derived from careful analysis of the procedure to be replicated. Metrics can be determined by trained psychologists from a direct analysis of the content of the job or task to be tested. The identification of these critical measures of performance is a complex process which must be tailored to a training curriculum to be effective. Simulators based on flawed metrics will invariably lead to unsatisfactory assessment. It follows that simulator development must involve the statutory licensing authorities. Equally it is essential that we do not assume that training on a particular simulator will correlate with the ability to perform the task in the real world. This "transfer of training" must be rigorously proven by validation studies.

Clinical Competence↗
PubMed2003

Aortic side branch perfusion alone does not account for high intra-sac pressure after endovascular repair (EVAR) in the absence of graft-related endoleak.

OBJECTIVE: to examine the effect of stent-graft deployment on pressure within an aneurysm sac and to investigate the potential sources of intra-sac pressure. MATERIAL AND METHODS: intra-sac pressure was monitored during and immediately after endovascular repair via an indwelling catheter. Intra-sac pressure was also monitored during conventional open repair and was compared with the pressure measured within patent lumbar and inferior mesenteric side-branches, both before and after restoration of iliac arterial blood flow. Intra-sac and side-branch pressures were recorded and expressed as ratios of simultaneously measured radial artery pressure. RESULTS: in the absence of a graft-related endoleak (23/25 patients), endovascular repair resulted in a significant reduction in intra-sac pulse pressure (median ratio 0.31 IQR 0.10-0.46). There was no corresponding reduction in mean intra-sac pressure (median ratio 0.91; IQR 0.83-1.00). Application of clamps at conventional open repair resulted in a fall in both intra-sac pressure (median ratio 0.39, IQR 0.32-0.64) and pressure within side-branches (median ratio 0.45, IQR 0.33-0.64). Restoration of iliac blood flow resulted in a modest recovery of the side-branch pressure (median ratio 0.63, IQR 0.57-0.81), which nonetheless remained significantly less than the intra-sac pressure recorded after EVAR (p=0.01). CONCLUSION: reperfusion of the aneurysm sac through patent side-branches seems insufficient to account for persistent pressurisation of the aneurysm after endovascular repair. This finding supports the hypothesis that pressure may be transmitted directly through stent-graft fabric.

Aortic Aneurysm↗
PubMed2001

Decision analysis for small, asymptomatic intracranial arteriovenous malformations.

OBJECT: Asymptomatic intracranial arteriovenous malformations (AVMs) represent a clinically challenging problem because of the complex decision making that must be undertaken prior to beginning any type of treatment. In addition, the relative infrequency of these lesions means that there is relatively little experience reported in the literature. The authors use a decision-analysis technique to model the considerations that go into determining the treatment of these lesions in an effort to quantify the various risks and overall benefits conferred by the following three treatment strategies: observation/natural history, microsurgery, and stereotactic radiosurgery. METHODS: The authors conducted a thorough literature search to elucidate the risks and outcomes associated with each treatment option. These values were used to build and run a comprehensive Markov model to determine a base-case analysis. All of the input variables were also subjected to sensitivity analysis to identify the most influential input variables and the crossover points in which favored strategies changed. The base-case analysis suggested that microsurgery was the favored treatment option because this hypothetical cohort accumulated 21.53 quality-adjusted life years (QALYs) over the course of the model compared with the 16.97 QALYs and 16.40 QALYs for stereotctic radiosurgery and observation, respectively. Sensitivity analysis demonstrated that overall major neurological morbidity and mortality were the most influential input variables both perioperatively and during the radiosurgical "latent" period (that is, up to 2 years posttreatment). The maximum acceptable perioperative combined major neurological morbidity and mortality rate was 6.8%. The latent period combined major neurological morbidity and mortality would need to be 0.7% to make radiosurgery favorable in this analysis. CONCLUSIONS: Results of this decision analysis model suggest that microsurgery in the hands of experienced cerebrovascular surgeons, who can expect a less than 6.8% combined rate of major neurological morbidity and mortality, offers patients a greater overall quality of life over time.

Algorithms↗
PubMed2001

Aortic side branch embolization before endovascular aneurysm repair: incidence of type II endoleak.

PURPOSE: To assess the feasibility of embolization of aortic side branches and its impact on the incidence of type II endoleak after endovascular aneurysm repair. MATERIALS AND METHODS: Endovascular aneurysm repair was performed in 74 patients. Aortic side branch vessels were evaluated on the preoperative angiogram and computed tomography (CT) and, where embolization of lumbar and inferior mesenteric vessels was considered technically possible, this was attempted prior to endovascular repair. Follow-up CT was used to assess the presence of type II endoleak. RESULTS: Seventy-two patients were followed up for longer than 1 month. Embolization was attempted in 25 cases, successfully in 10, with partial success in 11, and failure in four. Twenty patients with successful or partly successful preoperative embolization were discharged and followed-up. Four (20%) had demonstrable type II endoleak during follow-up, with two of these persisting at latest follow-up. Of 43 patients without previous embolization, there were 10 (23.3%) type II endoleaks during the follow-up period, four of these persisting. In cases with type II endoleak, mean sac diameter change was -0.5 mm in the cases with previous embolization and +3.1 mm without. The mean period to onset of type II endoleak was 6.9 months without, and 15.3 months with, previous embolization. CONCLUSION: Although the cohort size is below a level that would confer significance, the trend of these findings is such as to suggest a lack of influence of aortic side branch embolization on the incidence of type II endoleak during the follow-up period.

Angiography↗
PubMed2001

Perianeurysmal fibrosis: a relative contra-indication to endovascular repair.

OBJECTIVE: Perianeurysmal fibrosis (PAF) with involvement of neighbouring viscera can render open repair of inflammatory aneurysms technically difficult and therefore hazardous. For this reason, endovascular repair (EVAR) has been advocated as the preferred approach for this condition. EVAR is known to induce a systemic inflammatory response in patients but the nature of the local response remains unknown. If significant, such a response could exacerbate rather than ameliorate PAF. The aim of the study was to examine the incidence, course and consequences of perianeurysmal fibrosis detected by computerised tomography (CT) before and after EVAR. MATERIAL AND METHODS: The clinical records of patients treated by EVAR and followed for at least 6 months were reviewed. Pre and post-operative CT images were independently graded for PAF by three radiologists according to a standard protocol. RESULTS: PAF was documented preoperatively in six out of a total of 61 patients. In two of these PAF worsened after EVAR resulting in ureteric obstruction and hydronephrosis requiring ureteric stents. In the remaining 4 patients PAF did not reduce postoperatively. PAF of low grade developed postoperatively in 10 out of 55 patients (18%) in whom there was no evidence of PAF on preoperative imaging. Median follow-up was 18 months (range 6-36 months). The development of periaortic fibrosis de novopostoperatively was statistically significant (McNemar's test p=0.002). CONCLUSION: EVAR does not seem to reverse PAF if this is present preoperatively and it induces this condition in approximately one sixth of patients without evidence of preoperative PAF. The potential for this adverse inflammatory local response should be taken into account when considering EVAR for treatment of aneurysms with perianeurysmal fibrosis and must be weighed against the perceived benefits of this approach.

Aged↗
PubMed2001

The experiences and challenges of informal caregivers: common themes and differences among whites, blacks, and hispanics.

PURPOSE: This study examined commonalities and differences in the experiences and challenges of White, Black, and Hispanic informal caregivers in New York, NY. DESIGN AND METHODS: A randomly selected representative cross-section of 2,241 households was contacted through telephone interviews. Complete data were available for 380 eligible participants, who were classified as White (n = 164), Black (n = 129) and Hispanic (n = 87). Descriptive, bivariate, and multivariate analyses were conducted to examine differences in caregiving intensity, reported difficulty with providing care, and having unmet needs with care provision. RESULTS: Over 70% of caregivers had no help from formal caregivers, even though over 80% had been providing care for at least 1 year, and 40% had been providing this care for 20 or more hr per week. Compared with White caregivers, Black caregivers were more likely to provide higher intensity care, to report having unmet needs with care provision, and to experience increased religiosity since becoming caregivers, but were less likely to report difficulty with providing care. Hispanic caregivers were more likely than White caregivers to have help from formal caregivers and to experience increased religiosity since becoming caregivers. IMPLICATIONS: Although many similarities exist in the experiences and challenges of informal caregivers, gaining insight from different populations of family caregivers would help program planners, policy makers, and formal caregivers to develop and implement culturally sensitive programs and policies that are supportive of the needs of these caregivers in their ever-expanding roles. Future efforts also should focus on exploring the potentially significant role that community resources, in particular, religious institutions, could play in providing outreach and support to racial/ethnic minority caregivers.

Adolescent↗
PubMed2000

Cost-effectiveness of surgery for small abdominal aortic aneurysms on the basis of data from the United Kingdom small aneurysm trial.

PURPOSE: Although the United Kingdom small aneurysm trial reported no survival benefit for early operation in patients with small (4. 0-5.5 cm) abdominal aortic aneurysms (AAAs), the trial lacked statistical power to detect small but potentially meaningful gains in life expectancy, particularly for specific subgroups. We used decision analysis to better characterize the potential benefits and cost-effectiveness of early surgery. METHODS: We used a Markov model to assess the marginal cost-effectiveness (incremental cost per quality-adjusted life year [QALY] saved) of early surgery relative to surveillance for small AAAs, using data from the UK Trial. Subgroup analyses were performed by patient age and AAA diameter. Sensitivity analysis was used to evaluate the effect of elective operative mortality on cost-effectiveness. RESULTS: In our baseline analysis, early operations provided a small survival advantage (0.14 QALYs) at a small incremental cost of $1510. Thus, despite a small survival benefit, early surgery appeared cost-effective ($10, 800/QALY). The small cost differential resulted from the large proportion of patients who underwent surveillance, who eventually underwent AAA repair, and therefore incurred the cost of the surgical procedures. The survival advantage and cost-effectiveness of early operation increased with lower operative mortality, younger age, and larger AAA diameter. CONCLUSION: Despite the negative conclusions of the UK trial, early surgery may be cost-effective for patients with small AAAs, particularly younger patients (<72 years of age) with larger AAAs (> or = 4.5 cm). Because the gains in life expectancy are relatively small, however, clinical decision making should be strongly guided by patient preferences.

Age Distribution↗
PubMed2000

Freedom from endoleak after endovascular aneurysm repair does not equal treatment success.

OBJECTIVE: To determine whether freedom from endoleak after endovascular repair of abdominal aortic aneurysm (EVAR) is a reliable guide to freedom from persistent or recurrent pressurisation of the aneurysm sac (endotension) and therefore freedom from risk of rupture. PATIENTS AND METHODS: The records of 55 patients followed for more than 3 months after EVAR were reviewed to correlate the presence or absence of endoleak on contrast-enhanced CT and/or angiography with changes in maximum aneurysm diameter (DMAX). RESULTS: in 22 (40%) patients there was no significant change in DMAX during follow-up. In 21 of these no endoleak was observed on CT or angiography. One patient developed a secondary side-branch endoleak which remains under observation. In 18 (33%) patients, DMAX decreased during follow-up. Thirteen of these remained free of endoleak. Four patients developed secondary endoleaks which were treated by secondary intervention. One patient with persistent primary endoleak suffered fatal aneurysm rupture three days before planned intervention. DMAX increased in 15 (27%) patients. In only five of these could an endoleak be identified on CT and/or angiography. One primary side-branch endoleak persists following failed embolisation. Four secondary endoleaks have been corrected by secondary intervention. Four of the remaining 10 patients died suddenly from unknown cause. All had DMAX greater than 65 mm at last follow-up. One patient underwent late conversion, which suggested continued pressurisation through thrombus at the site of a "sealed" primary proximal endoleak. Two patients are scheduled to undergo embolisation of patent side-branches revealed only by Levovist enhanced Duplex scanning and three patients remain under observation. CONCLUSION: Freedom from endoleak on conventional imaging incorrectly suggested freedom from endotension in 10 (18%) of our patients. Follow-up after endovascular repair must include regular measurement of DMAX and/or aneurysm sac volume to identify those patients who remain at risk of rupture.

Aged↗
PubMed2000

The role of the pulmonary afferent receptors in producing hemodynamic changes during hyperinflation and endotracheal suctioning in an oleic acid-injured animal model of acute respiratory failure.

The purpose of this study was to examine the role of the pulmonary afferent receptors in producing hemodynamic changes during hyperinflation and endotracheal suctioning (ETS) in an oleic acid-injured animal model of acute respiratory failure. Previous investigations of hyperinflation as a method to prevent hypoxia-induced sequelae of ETS have demonstrated unrecognized hemodynamic consequences. In this within-subject, repeated-measures study, instrumented, oleic acid-injured dogs had continuous measurements of heart rate (HR), mean aortic blood pressure (MAP), left ventricular pressure (Plv), pulmonary artery pressure (Ppa), right ventricular afterload (Ppa(tm)), right atrial pressure (Pra), and right ventricular filling pressure (Pra(tm)) during hyperinflation and ETS when the vagi were intact and after the pulmonary branches of the vagus nerves had been severed. After severing the vagi, MAP and Plv were decreased and HR and Ppa were increased. With the vagi severed, there was less variation in MAP and Ppa but increased variation in HR. These findings suggest that vagally mediated reflexes from the lungs produce some, but not all, of the hemodynamic effects associated with hyperinflation and ETS. Continued research is necessary to discover a method of hyperoxygenation and suctioning that does not produce potentially harmful hemodynamic effects.

Afferent Pathways↗
PubMed1999

Use of contrast-enhanced ultrasound in follow-up after endovascular aortic aneurysm repair.

PURPOSE: To investigate the use of contrast-enhanced ultrasound in the detection of endoleak after endovascular repair of abdominal aortic aneurysm. MATERIALS AND METHODS: Eighteen patients underwent follow-up on 20 occasions after endovascular aortic aneurysm repair by arterial-phase contrast-enhanced spiral computed tomography (CT). All patients had unenhanced color Doppler ultrasound and Levovist-enhanced ultrasound on the same day. The ultrasound examinations were reported in a manner that was blind to the CT results. CT was regarded as the gold standard for the purposes of the study. RESULTS: There were three endoleaks shown by CT. Unenhanced ultrasound detected only one endoleak (sensitivity, 33%). Levovist-enhanced ultrasound detected all three endoleaks (sensitivity, 100%). Levovist-enhanced ultrasound indicated an additional six endoleaks that were not confirmed by CT (specificity, 67%; positive predictive value, 33%). In one of these six cases, the aneurysm increased in size, which indicates a likelihood of endoleak. Two of the remaining false-positive results occurred in patients known to have a distal implantation leak at completion angiography. CONCLUSION: In this small group of patients, contrast-enhanced ultrasound appears to be a reliable screening test for endoleak. The false-positive results with enhanced ultrasound may be due to the failure of CT to detect slow flow collateral pathways. Although the number of patients in this study is small, enhanced ultrasound may be more reliable than CT in detecting endoleak.

Aged↗
PubMed1999

Emergency obstetric hysterectomy - an increasing incidence.

Ten women underwent obstetric hysterectomy at St George's Hospital, London between 1992 and 1998, with an apparent seven-fold increase in incidence in recent years. All hysterectomies were performed as emergency procedures, with massive postpartum haemorrhage being the major indication for operation in nine cases. Abnormal placentation was the single commonest cause, seven cases being associated with previous caesarean section. There were no maternal or fetal mortalities, but major surgical complications, including urinary tract and vascular injury occurred in one case. In view of the increasing risk of obstetric hysterectomy following previous caesarean section, high risk cases associated with abnormal placentation may be identified using ultrasound, allowing appropriate pre-operative counselling regarding the risk of peripartum hysterectomy.

Journal Article↗
PubMed1996

Developing patient and family education programs for a transplant center.

Patient and family education is an important component of the organ transplant programs at the University of Nebraska Medical Center. The Medical Center is in the process of planning a new transplant center which will employ the family-centered, educationally-intensive cooperative care concept. This approach was chosen as the model for the delivery of care at the Lied Transplant Center because it emphasizes efficient, effective clinical care by requiring active participation by the family or essential other, thereby better preparing both the patient and the family for the transition to home and to the community. This article presents the evolution of patient education in our transplant programs, discusses the educational needs of transplant patients across the continuum of care, provides insight into the process of planning educational programs for the new center and provides a sample module for teaching which is based on the Cooperative Care concept.

Curriculum↗
PubMed1994

Self-reported childhood abuse in an adult population in a primary care setting. Prevalence, correlates, and associated suicide attempts.

OBJECTIVE: To describe the prevalence of childhood physical, sexual, and emotional abuse and suicide attempts in a sample of adult patients from a primary care setting and to examine the relationship between suicide attempts and a self-reported history of childhood abuse. DESIGN: Cross-sectional sampling via a self-administered survey that included an abuse questionnaire, the Inventory to Diagnose Depression, and questions regarding suicide. SETTING: University medical center family medicine practice. PATIENTS: A convenience sample of patients aged 18 years and older presenting for care. Of the 778 patients approached, 448 patients (58%) consented and returned their surveys. We report only on the 292 surveys (38%) returned with complete information. Subjects were predominantly middle class and white, with a mean age of 37 years. MEASUREMENT AND MAIN RESULTS: Forty-four percent of the patients reported experience of childhood abuse, and 22% reported multiple forms of abuse. Eighteen percent of abused vs 3% of nonabused patients (P = .00001) reported a history of suicide attempts. Being female, younger, and less educated were associated with any abuse. Females reported more sexual abuse; less educated patients, more physical abuse; and younger patients, more physical and sexual abuse and suicide attempts. Odds ratios for suicide attempts, when adjusted by abuse status, were 6.4 for any abuse (95% confidence intervals [CI], 2.4 to 17.6), 4.1 for sexual abuse (95% CI, 1.7 to 9.9), 3.7 for emotional abuse (95% CI, 1.4 to 10.0), and 1.2 for physical abuse (95% CI, 0.5 to 3.1). CONCLUSION: A history of childhood abuse was a common experience in this sample. Patients with a history of abuse, particularly sexual and emotional abuse, are at increased risk of suicidal behavior. To facilitate more appropriate care and treatment, primary care practitioners should question patients regarding a history of abuse.

Adult↗
PubMed1994

Embolization in the palliation of complications of inoperable primary pancreatic neoplasms.

Primary pancreatic neoplasm typically presents at an advanced stage where surgical management may not be feasible. These patients are often symptomatic due to biliary obstruction but problems may also include gastrointestinal bleeding and endocrinological complications. We describe two cases illustrating the use of palliative embolization in the control of biochemical and haemorrhagic complications of primary pancreatic neoplasm. In one case, massive gastrointestinal bleeding from an inoperable primary pancreatic carcinoma was controlled by two embolization procedures to produce devascularization of the primary lesion. In a second case, life-threatening hypercalcaemia was thought to be due to secretion of a parathormone-like material from an inoperable islet cell tumour. There was no evidence of liver metastases and the pancreatic mass was embolized, following which serum calcium was reduced to near normal levels with considerable clinical improvement. We conclude that there is a role for embolization of inoperable primary pancreatic neoplasm in the palliation of biochemical or haemorrhagic complications of these tumours.

Adenocarcinoma↗