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Biomedical subjects

C R Quick

Publications and source records attributed to C R Quick.

At least 19 recordsLinked to original sources
PubMed1999

The association between cigarette smoking and abdominal aortic aneurysms.

PURPOSE: The purpose of this study was to investigate the precise effect of smoking, duration of smoking, and cessation of smoking on the risk of the development of an abdominal aortic aneurysm (AAA). METHODS: A nested case control study was carried out in a population-based screening program for men over the age of 50 years. Smoking data were collected by questionnaire, and serum levels of cotinine were used as an objective measure of nicotine exposure. RESULTS: Data of 210 cases and 237 control individuals were analyzed. Current smokers were 7.6 times more likely to have an AAA than nonsmokers (95% confidence interval, 3.3%-17.8%). Exsmokers were 3.0 times more likely to have an AAA than nonsmokers (95% confidence interval, 1.4%-6.4%). Duration of smoking was significantly associated with an increased risk of AAA, and there was a clear linear dose response relationship with the duration of smoking; each year of smoking increased the relative risk of AAA by 4% (95% confidence interval, 2%-5%). In contrast, the effect of the amount smoked disappeared when an adjustment was made for the duration of smoking. After the cessation of smoking, there was a very slow decline in the risk of the occurrence of an AAA. Smoking was associated with a higher relative risk of a small aneurysm than a large aneurysm. Serum cotinine levels were higher in men with a small aneurysm than in men with a large aneurysm. Cotinine levels were similar in expanding aneurysms and stable aneurysms. CONCLUSION: The duration of exposure rather than the level of exposure appears to determine the risk of the development of an AAA in men older than 50 years. The slow decline of risk after the cessation of smoking and the higher relative risk for small compared with large aneurysms suggest that smoking is an initiating event for the condition.

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PubMed1999

The influence of screening on the incidence of ruptured abdominal aortic aneurysms.

PURPOSE: The purpose of this study was to estimate the influence of a screening program on the incidence and mortality of ruptured abdominal aortic aneurysms (RAAAs). METHODS: The effects of screening on the incidence and death rate of RAAAs were investigated with a stepped wedge study design. RAAAs that occurred in the Huntingdon district were traced with an examination of all hospital records and community postmortem records. RESULTS: During the 5-year period from 1991 to 1996, 78 RAAAs occurred in the Huntingdon district: 62 in men and 16 in women. Eleven of the 62 men with RAAAs had been invited for screening. The incidence of RAAA in the invited group was 3.7 per 10,000 person-years (py; 95% confidence interval [CI], 1.5 - 7.3). In the noninvited group, the incidence was 7.3 per 10,000 py (95% CI, 5.3. - 9.2), a rate ratio of 0.51 (95% CI, 0.26 - 0.97). The mortality of rAAAs in the invited group was 3.0 per 10, 000 py (95% CI, 1.4 - 5.4) as compared with 5.4 per 10,000 py in the noninvited group (95% CI, 3.9 - 7.3), resulting in a rate ratio of 0. 55 (95% CI, 0.26 - 1.15). CONCLUSION: Screening for asymptomatic AAAs can reduce the incidence rate of RAAAs by 49% (95% CI, 3% - 74%).

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PubMed1999

Incidence among men of asymptomatic abdominal aortic aneurysms: estimates from 500 screen detected cases.

OBJECTIVES: To determine the incidence of asymptomatic abdominal aortic aneurysms and the implications for an ultrasound screening programme in England and Wales. METHODS: First screen data were obtained from the Chichester and Huntingdon screening studies and used to estimate the prevalence of abdominal aortic aneurysms. The incidence of new, asymptomatic aneurysms was estimated from the prevalence rates observed in the Huntingdon screening study. SETTING: Screening programmes in Huntingdon and Chichester using ultrasound to screen all men over the age of 50 and men over age 65 respectively. RESULTS: The prevalence of abdominal aortic aneurysms ranged between 5.32% and 8.02% and between 6.18% and 9.88% of men aged between 65 and 79 in Chichester and Huntingdon respectively. Annual incidence rates, estimated by age, rose steadily reaching a peak of 0.67% of the Huntingdon population per year at age 65. Thereafter incidence falls. Estimates of the incidence of new asymptomatic abdominal aortic aneurysms, based on the observed prevalence data, were calculated and showed a peak at age 65. CONCLUSIONS: Hypotheses are offered to explain this unexpected early peak in incidence. This information should allow the definition of the optimum age for screening, and the relative benefits of screening at different intervals if widespread screening is adopted in the future.

Age Factors↗
PubMed1999

Ruptured abdominal aortic aneurysm in the Huntingdon district: a 10-year experience.

A study was undertaken to establish the true incidence of ruptured abdominal aortic aneurysms (RAAA) in the Huntingdon districts. RAAAs in the Huntingdon district between 1986 and 1995 were studied retrospectively. Data were collected from hospital records and hospital and community autopsies. There was a total of 139 cases of RAAA; 119 were males and 20 females, giving a M:F ratio of 6:1. The incidence of RAAAs was 17.8/100,000 person years (py) in males and 3.0/100,000 py in females. Mean age at rupture was 75.5 years in men (95% confidence intervals (CI) 74-78 years) and 80.2 in women (95% CI 78.8-83 years). There was an age-specific increase in incidence after the age of 65 years in men and after 80 years in women, although 12.6% of all RAAAs occurred in men under 65 years. In all, 100 patients were confirmed to have died of RAAA during the 10-year period. This represents 79% of all ruptures discovered. Almost three-quarters of patients did not reach the operating theatre. Of the 61 patients operated on, 29 survived (48%). The size of the aneurysm at rupture was recorded in 68 cases (49%). The mean size was 8.14 cm (SD 2.0 cm). In five cases (7.4%), rupture occurred in AAAs smaller than 6 cm. The overall mortality from RAAA in Huntingdon health district is approximately 80% and three-quarters of all deaths occurred without an operation.

Age Distribution↗
PubMed1998

The infrarenal aortic diameter in relation to age: only part of the population in older age groups shows an increase.

OBJECTIVES: To resolve whether the infrarenal aortic diameter (IAD) continues to increase throughout life; to ascertain the relationship between IAD and age, sex, body size, and smoking status, and to determine whether these factors influence the IAD over the entire range of aortic diameters or only in a proportion. SETTING: Combined cross-sectional data from two population-based screening programmes for abdominal aortic aneurysms (AAA) in Huntingdon (U.K.) and Rotterdam (The Netherlands). METHODS: The antero-posterior diameter of the infrarenal aorta was measured. The influences of age, gender, body size and smoking status were examined. RESULTS: Data were analysed from 3066 women and 8270 men. In men, mean IAD rose from 20.7 mm to 23.5 mm in the older age groups. However, IADs remained constant below the 75th perentile in men and the 85th percentile in women. Similarly only the top 15-25% of the aortic diameters were larger in smokers compared with non-smokers. CONCLUSIONS: The aortic diameter increased with age in only a minority of the population. Furthermore, known risk factors for AAA contributed to aortic dilatation in only the upper tail of the frequency distribution. Thus only 25% of men and 15% of women may be prone to aortic dilatation.

Age Factors↗
PubMed1998

Epidemiology and potential for prevention of abdominal aortic aneurysm.

BACKGROUND: Ruptured abdominal aortic aneurysm (AAA) is a common cause of death which is preventable by elective repair of an asymptomatic AAA. METHODS: The literature was reviewed with emphasis on epidemiological studies and population-based screening surveys. RESULTS AND CONCLUSION: The prevalence of small AAA ranges between 3 and 8 per cent. The incidence of asymptomatic AAA seems to be increasing, although exact incidence estimates vary. The most important risk factors for AAA are male sex, age, family history and smoking. Hypertension is associated with a mildly increased risk, but diabetes is not associated with any increase. Primary prevention of AAA is not a realistic option. There is no evidence of an effective medical treatment to prevent growth of small AAAs, although trials with propranolol are under way. The only intervention to prevent death from aneurysm is elective repair of the asymptomatic lesion. Screening for asymptomatic AAA can reduce the incidence of rupture. However, further studies are needed to determine the cost effectiveness of screening compared with that of other health programmes.

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PubMed1998

Growth rates and risk of rupture of abdominal aortic aneurysms.

BACKGROUND: Early identification of abdominal aortic aneurysms (AAAs) may reduce the risk of death from rupture by providing the opportunity for elective repair. Before a screening policy for AAA is implemented, the growth rates of AAAs and the accompanying risk of rupture without intervention should be established. METHODS: The growth rates of AAAs were calculated using longitudinal aneurysmal growth data from screening studies in Chichester and Huntingdon. Estimates of the growth rates of AAAs and the risks of rupture over time were made taking measurement error and individual variability into account. RESULTS: Growth rate estimates were found to vary by initial aortic diameter, with a more rapid growth seen in large aneurysms (50 mm or more). The rate of aneurysm growth did not differ with age or sex. The estimated risk of rupture of an AAA with an initial diameter of 45 mm did not exceed 20-5 per cent over 5 years. An AAA with an initial diameter of 30 mm has a 4.0 per cent or less chance of rupture over 5 years. CONCLUSION: The study provides a more accurate assessment of the risk of aneurysm rupture without surgery and helps to define rescreening intervals for those with an enlarged aortic diameter.

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PubMed1997

Midline extraperitoneal approach for elective abdominal aortic aneurysm repair.

The incidence of abdominal aortic aneurysms (AAA) is rising and elective repair is becoming more commonplace. We describe a new, simple midline extraperitoneal approach for AAA repair. It is particularly suitable for patients who have an inflammatory AAA, abdominal adhesions or a horseshoe kidney. This approach provides excellent exposure to the whole aortoiliac system without the need for separate incisions, whilst retaining the potential advantages of the extraperitoneal approach.

Aortic Aneurysm, Abdominal↗
PubMed1997

Quality of the measurement of the infrarenal aortic diameter by ultrasound.

OBJECTIVES: To assess quality and variability in measurements of the infrarenal aortic diameter by ultrasound, and to recommend quality control measures to improve consistency in measurements of the infrarenal aortic diameter (IAD) in a long running screening programme. SETTING: An aneurysm screening programme in Huntingdon. METHODS: Quality of the ultrasound image was subjectively assessed by each ultrasonographer. Quality of the measurements was assessed by analysing the frequency of measurements that were outside the normal variability of the estimated true diameter. The interobserver variability was measured by analysing repeated measurements of the IAD in the same patient by two ultrasonographers, using the same scanner. The variability between different scanners was measured by analysing repeat measurements of the IAD in the same patient by the same ultrasonographer, using two scanners. The intraobserver variability was estimated by analysing all patients with three consecutive measurements of the IAD, carried out by the same ultrasonographer. RESULTS: Although the subjective assessment of the quality of the ultrasound image of the aorta varied, there were no statistically significant differences in the likelihood of obtaining measurements outside the limits of agreement between the ultrasonographers. The interobserver, intraobserver, and between scanner variability of ultrasound measurements of the IAD were all around 6 mm. CONCLUSION: The variability in ultrasound measurements of aortic diameters is acceptable for clinical decision making, and the interobserver variability is very similar to the long term intraobserver variability. Quality control measures are suggested to maintain long term consistency of ultrasound measurements of the IAD.

Aorta, Abdominal↗
PubMed1996

Prolapsing gastric polyp, an unusual cause of gastric outlet obstruction: a review of the pathology and management of gastric polyps.

Gastric polyps are rare and largely asymptomatic, but attract importance because of their strong potential to progress to carcinoma. Rarely, pedunculated polyps arising in the antrum may prolapse through the pylorus, causing intermittent gastric outlet obstruction. We describe here our experience of four cases collected over a ten-year period, each presenting dissimilarly with this phenomenon. We review the literature referring to the pathogenesis of gastric polyps and their association with malignancy and other disorders. We proceed to discuss the efficacy of barium studies versus gastroscopy in detecting these lesions, the relative roles and merits of endoscopic polypectomy and surgery, and the importance of prolonged follow-up of patients harbouring gastric polyps.

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PubMed1995

Endovascular femoropopliteal bypass: a cadaveric study.

OBJECTIVE: Patency rates of standard femoropopliteal bypass in infra-inguinal occlusive disease have yet to be matched by minimally invasive percutaneous procedures. We report a feasibility study of a less invasive endovascular femoropopliteal bypass technique. METHODS: (1) groin exposure of femoral artery, (2) guidewire passage and mechanical dilatation of superficial femoral artery (SFA), (3) expandable helical cutter endarterectomy of SFA, (4) transluminal placement of PTFE graft, (5) graft balloon dilatation to shape and set distal interface and (6) end-to-end anastomosis of proximal graft to femoral artery. Development and testing was undertaken in 48 limbs of 26 fresh human cadavers. Limbs with no demonstrable SFA disease were excluded. Seventeen limbs had mild, diffuse disease. Three limbs had a single, short, tight stenosis. Seventeen limbs had multiple, high grade stenotic lesions 12-40 cm long (mean 24 cm). Eleven limbs had occlusive lesions, 8-38 cm long (mean 24 cm). RESULTS: We successfully completed the procedure in 39 (81%) limbs. We failed to complete the procedure in nine limbs; four from failed guidewire passage, four from vessel avulsion, and one from graft deployment failure. Histology confirmed endarterectomy cleavage in the standard plane. Angiography and explants demonstrated a patent graft and popliteal artery, and smooth distal graft/arterial interface with no obvious defects in 24 (62%) cases. Defects included combinations of: contrast extravasation/reflux, graft malpositioned/incorrectly sized, distal graft fold, and distal intimal flap. CONCLUSION: Endovascular femoropopliteal bypass is feasible and warrants further studies for possible clinical application.

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PubMed1994

Antibiotic irrigation and conservative surgery for major aortic graft infection.

PURPOSE: Traditional surgical treatment for panprosthetic aortic graft infection entails radical excision of the graft, aortic stump closure, and extraanatomic revascularization of the lower limbs. This carries an early mortality rate of 24% to 45%. Amputation rates range from 11% to 37%. Multiple operations and prolonged hospital stay are usual. We have developed a more conservative management technique with the aim of improving outcome. METHODS: We describe an innovative method of treating the condition with prolonged, high-dose, local antibiotic irrigation therapy, systemic antibiotic treatment, surgical debridement, and graft conservation in a prospectively studied series of 10 patients. RESULTS: The actual 30-day patient survival rate is 90%, the 1-year survival rate is 80%, and the 4-year survival rate is 67%. Two patients died because of graft infection, and the third died, uninfected, of an unrelated cause. No limbs have been amputated. Only two patients required a second operation. Mean postoperative hospital stay was 32 days. The seven survivors have been closely followed up with regular computed tomography or indium scanning and clinical examination and appear to be free from infection at a mean of 61 months after cessation of irrigation therapy. CONCLUSION: The technique appears to represent a significant improvement in the management of this major complication of vascular surgery.

Adult↗
PubMed1994

An abdominal aortic aneurysm screening programme for all males over the age of 50 years.

Previously published ultrasound screening programmes for abdominal aortic aneurysm (AAA) have concentrated on males in the 65 to 75 year age range, suggesting this as the most cost-effective cohort to target. In this unique study we have broadened the criteria for screening. General practitioners in one health district were approached to supply details of all males aged 50 years and over to be offered aortic ultrasound scanning. Over a period of 18 months, 4145 individuals were asked to attend and 3030 (73%) have attended. Attendance rates were: between 50 and 64 years, 73%; between 65 and 79 years, 75%; for 80 years and over, 64%--significantly less (p = 0.01-0.001) than the other two age bands. Aortic dilatation (diameter > or = 2.5 cm) was found in 6.3% of the 50 to 64 year age group, 16.8% of the 65 to 79 year age group, and 23.3% of the 80 years and over age group. An established aneurysm (> or = 4.6 cm) was found in 0.3%--6 individuals (50-64 years), 2.5% (65-79 years) and 4.1% (> or = 80 years). The results suggest that aortic screening may be worthwhile extending to a wider age band. By focusing follow-up, this should give greater value for younger men in terms of community productivity and allows for selective intervention in the elderly.

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PubMed1990

Conservative treatment of major aortic graft infection.

Major infections of Dacron aortic grafts involving the proximal anastomosis or the whole graft are rare but lethal. Traditional surgical treatment involves radical excision of the graft and extra-anatomic revascularisation of the lower limbs, and carries a forbidding mortality and complication rate. This paper describes an alternative conservative approach used on four patients, three of whom appear to have been successfully treated by continuous antibiotic irrigation of the prosthesis without removal of the graft, whilst the fourth died 42 months later of recurrent graft infection. This is the first time that prolonged survival has been reported following conservative treatment of major graft infection. The authors believe this method may offer substantial advantages over the traditional surgical treatment for this dreaded complication of aortic surgery.

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