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Biomedical subjects

G G Barber

Publications and source records attributed to G G Barber.

At least 19 recordsLinked to original sources

Aortitis and bilateral ureteral obstruction after endovascular repair of abdominal aortic aneurysm.

A bifurcated stent graft was used to treat an asymptomatic 5.4-cm abdominal aortic aneurysm in a 76-year-old man. No endoleaks or inflammatory changes were seen on the 1-month follow-up computed tomography scan. Five months later the patient had acute renal failure and ureteral obstruction secondary to significant inflammatory changes in the aneurysm wall. After bilateral ureteral stenting, conservative treatment included tamoxifen and steroid therapy. The patient remains symptom-free, and at 2-year follow-up a computed tomography scan demonstrated decreased inflammation and shrinkage of the excluded abdominal aortic aneurysm.

Acute Kidney Injury↗

Resection of right atrial tumor thrombi without circulatory arrest.

Resectable retroperitoneal tumors with right atrial tumor thrombus extension have been excised previously using cardiopulmonary bypass and deep hypothermic circulatory arrest. We have used a technique involving clamping of the descending aorta with avoidance of deep hypothermic circulatory arrest in 6 patients. The approach provided a virtually bloodless field and allowed complete resection to be performed with low morbidity.

Aged↗

Pharmacological management of intermittent claudication: a meta-analysis of randomised trials.

Intermittent claudication, a symptom of atherosclerosis in the large vessels of the lower limbs, greatly affects patient mobility and quality of life. Medical therapy for a moderate form of this condition includes vasodilators, antiplatelet agents and alternative treatments such as ginkgo biloba.A meta-analysis of results from 52 trials (including 5088 patients) was conducted for all current medical therapies for intermittent claudication. After 24 weeks, some of the medical therapies were found to be more effective than placebo for the primary end-points of either pain-free walking distance or maximum walking distance. Vasodilators presented the best results in walking distance. Pentoxifylline offered better results than naftidrofuryl, although the treatment benefit, measured in additional metres walked with treatment than without, was modest. Antiplatelets, ginkgo biloba and levocarnitine were slightly more effective than placebo, although the treatment benefit was of limited clinical importance. On average, patients walked 60m further with therapy than without, and only about half of that added distance was pain-free. Very little consistent information was available for other clinical end-points, such as overall mortality and adverse effects. These data suggest that some of the medical therapy, pentoxifylline in particular, can only modestly increase functional status in patients with moderate intermittent claudication. There is a need for uniformity in research design and reporting of trials. A future trial comparing medical therapy with physical therapy is indicated.

Humans↗

Management of intermittent claudication with pentoxifylline: meta-analysis of randomized controlled trials.

OBJECTIVE: To evaluate the efficacy of pentoxifylline therapy in improving the walking capacity of patients with moderate intermittent claudication. DATA SOURCES: A search of MEDLINE for trials published between 1976 and 1994 inclusive, and a bibliographic review of all articles retrieved. STUDY SELECTION: Randomized, placebo-controlled, double-blind clinical trials were selected that evaluated the pain-free walking distance (the distanced walked on a treadmill before the onset of calf pain) and the absolute claudication distance (the maximum distance walked on a treadmill) among patients with moderate intermittent claudication. Twelve study groups in 11 trials were included in the analysis. DATA EXTRACTION: In addition to information regarding the trial design, patient characteristics, dosages and treatment periods, the means and standard deviations were collected for both the pain-free walking and absolute claudication distances. Trial quality was also assessed. DATA SYNTHESIS: Overall, there was a statistically significant improvement in the pain-free walking distance after pentoxifylline therapy (weighted mean difference 29.4 m [95% confidence interval (CI) 13.0 to 45.9 m]); this finding was based on a total sample of 612 patients (308 in the treatment groups and 304 in the control groups). A significant improvement was also noted in the absolute claudication distance (weighted mean difference 48.4 m [95% CI 18.3 to 78.6 m]); this was based on a total sample of 511 patients (258 in the treatment group and 253 in the control group). In a sensitivity analysis of the pain-free walking distance, significant treatment effects and no statistically significant heterogeneity were found when only trials were included that were "medically eligible" (involved patients with stage II disease and a pain-free walking distance of 50 to 200 m). In a similar sensitivity analysis of the absolute claudication distance, the two conditions resulting in a significant treatment effect and no significant heterogeneity were the inclusion of "medically eligible" trials and those with a shorter treatment duration (13 weeks or less). CONCLUSION: Pentoxifylline therapy may be efficacious in improving the walking capacity of patients with moderate intermittent claudication. However, properly conducted clinical trials are required to provide a true estimate of the benefit.

Chi-Square Distribution↗

Perioperative ischaemia in aortic surgery: combined epidural/general anaesthesia and epidural analgesia vs general anaesthesia and i.v. analgesia.

PURPOSE: The goal of this randomized study was to determine whether combined general and epidural anaesthesia with postoperative epidural analgesia, compared with general anaesthesia and postoperative intravenous analgesia, reduced the incidence of perioperative myocardial ischaemia in patients undergoing elective aortic surgery. METHOD: Patients were randomly assigned to one of two groups. One group (EPI, n = 48) received combined general and epidural anaesthesia and postoperative epidural analgesia for 48 hrs. The other group (GA, n = 51) received general anaesthesia followed by postoperative intravenous analgesia. Anaesthetic goals were to maintain haemodynamic stability (+/- 20% of preoperative values), and a stroke volume > 1 ml.kg-1. A Holter monitor was attached to each patient the day before surgery. Leads 11, V2, and V5 were monitored. Myocardial ischaemia was defined as ST segment depression > 1 mm measured at 80 millisec beyond the J point or an elevation of 2 mm 60 millisec beyond the J point which lasted > 60 sec. An event that lasted > 60 sec but returned to the baseline for > 60 sec and then recurred, was counted as two separate events. The Holter tapes were reviewed by a cardiologist blind to the patient's group. RESULTS: There were no demographic differences between the two groups. Myocardial ischaemia was common; it occurred in 55% of patients. In hospital, preoperative ischaemia was uncommon (GA = 3, EPI = 8). Intraoperative ischaemia was common (GA = 18, EPI = 25). Mesenteric traction produced the largest number of ischaemic (GA = 11, EPI = 11) events. Postoperative ischaemia was most common on the day of surgery. Termination of epidural analgesia produced a burst of ischaemia (60 events in 9 patients). CONCLUSION: Combined general and epidural anaesthesia and postoperative epidural analgesia do not reduce the incidence of myocardial ischaemia or morbidity compared with general anaesthesia and postoperative intravenous analgesia.

Aged↗

Venous gangrene of the extremities.

OBJECTIVE: To review the rare clinical condition of venous gangrene of the extremities, particularly in association with malignant disease; to develop a treatment scheme for this difficult condition. DATA SOURCES: Surgical articles on phlegmasia cerulea dolens, venous gangrene and other forms of noninfectious, nonarterial gangrene of the extremities from 1937 to the present were identified from published indexes and computer databases; experience with four additional cases treated by the authors is incorporated. STUDY SELECTION: Studies selected for detailed review include those involved directly with venous gangrene and its investigation and treatment, and those relating to investigation of clinically similar conditions. DATA EXTRACTION: Because of the rarity of venous gangrene, much of the available literature is descriptive, involves small numbers of cases and describes only limited experience with investigation and treatment; data extraction was done by a single reviewer. DATA SYNTHESIS: Because of advances in diagnostic technology and thrombosis research, the assessment of suspected venous gangrene has changed significantly in recent years. Despite these advances, the prognosis for patients with this condition continues to be poor. The possible confounding roles of paradoxical reactions to anticoagulants and of primary hypercoagulable states are considered. CONCLUSIONS: Objective demonstration of extensive thrombosis of the large veins of the involved extremity remains central to the diagnosis. The presence and stage of any associated malignant lesion must be rapidly determined to allow planning for further treatment. Because conventional anticoagulation frequently fails, it may be necessary to consider less well-established modes of therapy.

Adenocarcinoma↗

Endarterectomy versus angioplasty in the treatment of localized stenosis of the abdominal aorta.

OBJECTIVE: To compare the outcome after aortoiliac endarterectomy and percutaneous transluminal angioplasty (PTA) of the aorta for localized stenosis of the lower abdominal aorta. DESIGN: Chart review of patients treated over a 5-year period. SETTING: A university centre. PATIENTS: Sixteen women, all of whom were smokers; 5 had hyperlipidemia, 4 had evidence of coronary artery disease, 3 were hypertensive, and 1 was diabetic. INTERVENTIONS: Aortoiliac endarterectomy (eight women) and PTA (eight women). MAIN OUTCOME MEASURES: Ankle-brachial pressure index (ABI), degree of claudication and clinical outcome. RESULTS: Angiography showed localized stenosis of the lower aorta in all patients, aortic hypoplasia in nine patients and associated common iliac disease in seven. None of the eight patients managed by aortoiliac endarterectomy had complications or died. All were free of claudication at a mean follow-up of 29 months and had durable improvement in their ABI: mean ABI preoperatively was 0.69 (standard deviation [SD] 0.1) and postoperatively was 1.06 (SD 0.07). Of the eight patients treated by PTA, only one had partial dilatation; another had a subintimal tear with worsening symptoms and a fall in ABI, requiring surgery within 18 months. The remaining six were symptom free after a mean follow-up of 13.4 months. Aortic PTA resulted in improvement of the ABI: mean ABI before PTA was 0.69 (SD 0.19) and after PTA was 1.06 (SD 0.15). CONCLUSIONS: Endarterectomy is a safe and effective method of treating occlusive disease limited to the distal aorta. PTA appears to be less reliable. However, it is recommended as the initial treatment of choice in patients with angiographically suitable lesions because it is less invasive.

Adult↗

Cardiac risk stratification using dipyridamole myocardial perfusion imaging and ambulatory ECG monitoring prior to vascular surgery.

Both dipyridamole myocardial perfusion imaging (cardiolite) and ambulatory ECG monitoring (Holter) for silent ischaemia have been found to be useful for stratification of cardiac risk in patients undergoing vascular surgery. The purpose of this study was to compare the diagnostic accuracy of these two non-invasive tests for prediction of perioperative cardiac events. One hundred patients (86 males, 14 females; mean age 67 +/- 8 years) underwent out-patient 48 h Holter monitoring and cardiolite imaging prior to vascular surgery (70 abdominal aortic aneurysm, 21 aortobifemoral, nine femoralpopliteal grafts). Ischaemia on Holter was defined as one or more episodes of ST segment depression 1 mm or greater, lasting 1 min or longer. Myocardial perfusion imaging was carried out with the high dose dipyridamole protocol (0.84 mg/kg), cardiolite and planar imaging. Ischaemia was defined as a segmental perfusion abnormality following dipyridamole with improved perfusion on rest imaging. Holter was positive for ischaemia in 34/100 patients (34%). Cardiolite scans were positive for ischaemia in 30/100 patients (30%). Perioperative myocardial infarction occurred in nine patients (two cardiac deaths). [table: see text] The diagnostic accuracy of the two tests was similar, with a low positive predictive value of 15-20%, and an extremely high negative predictive value of 94-96%. The event rate in patients with both tests negative was 2/48 (4.2%), with only one test positive 3/40 (7.5%) and with both tests positive 4/12 (33%). A reasonable approach to risk stratification would be to obtain either a Holter or cardiolite scan initially.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Ancrod versus heparin for anticoagulation during vascular surgical procedures.

PURPOSE: The purpose of this study was to compare the conduct and early results of infrainguinal vascular reconstructions with use of ancrod or heparin for anticoagulation. METHODS: To test the hypothesis that ancrod was an effective alternative to heparin, 28 patients requiring infrainguinal bypass surgery were randomized to receive heparin during operation or ancrod before operation over a period of 12 hours to deplete circulating fibrinogen (0.2 to 0.5 gm/L). RESULTS: No clotting of blood within the grafts or native vessels was noted during the conduct of the surgical procedures in either group. No excessive bleeding was detected during operation in either group. The operative procedure, complication rate, and hospital course were also indistinguishable; patency at 1 month was also equal. CONCLUSION: Fibrinogen depletion with ancrod provides anticoagulation for the conduct of infrainguinal vascular reconstructions that is as effective as heparin. When heparin is contraindicated ancrod is an effective and safe alternative.

Aged↗

The natural history of abdominal aortic aneurysms.

This study examines the rate of expansion of abdominal aortic aneurysms and the risk of rupture in relation to their size. To assess these variables, we conducted a prospective study of 300 consecutive patients who presented over a 6-year interval with abdominal aortic aneurysms (AAA) that were initially managed nonoperatively. The mean age of the patients was 70.4 years, and 211 (70%) were men. The mean initial aneurysm diameter was 4.1 cm. Among the 208 patients who underwent more than one ultrasound or computed tomographic (CT) scan, the diameter of the aneurysm increased by a median of 0.3 cm per year. The 6-year cumulative incidence of rupture was 1% and 2% among patients with aneurysms less than 4.0 cm and 4.0 to 4.9 cm in diameter, respectively (p greater than 0.05). In comparison, the 6-year cumulative incidence of rupture was 20% among patients with aneurysms greater than 5.0 cm in diameter (p less than 0.004). We conclude that (1) abdominal aortic aneurysms expand at a median rate of 0.3 cm per year; and (2) the risk of rupture of abdominal aortic aneurysms less than 5.0 cm is substantially lower than the risk of rupture of aneurysms 5.0 cm or more in diameter.

Adult↗

Lymphatic fistula after vascular reconstruction: a case-control study.

A retrospective case-control study was carried out to assess the importance of lymphatic fistulas that develop after vascular reconstruction and to determine the risk factors associated with them. The authors compared 35 patients who had lymphatic fistula after vascular reconstruction with 70 control patients, taken from the same database. They found a significant difference between the two groups only in age and indication for surgery: lymphatic fistulas were more likely to develop in older patients and in patients who underwent aortobifemoral bypass for limb salvage rather than for claudication (p less than 0.05).

Aged↗

Atypical hepatic vein leiomyoma extending into the right atrium: an unusual cause of the Budd-Chiari syndrome.

A 14-year-old male presented with a one week history of weakness, lightheadedness and vomiting. Bilateral pleural effusions were evident on chest radiography; electrocardiogram revealed decreased voltages. Echocardiogram, abdominal ultrasound and magnetic resonance imaging revealed a mass in an hepatic vein and the inferior vena cava extending up to and filling the right atrium. Under deep hypothermia and extracorporeal circulation the mass was removed en bloc. It originated from the hepatic vein. Pathology revealed a smooth muscle tumour intermediate between benign and malignant (atypical leiomyoma). This is the first reported pediatric primary leiomyoma of the hepatic vein. It caused the Budd-Chiari syndrome, a rare pediatric entity.

Actins↗

Factors affecting survival after rupture of abdominal aortic aneurysm: effect of size on management and outcome.

Between 1970 and 1985, 172 consecutive patients (146 men, 26 women) underwent repair of ruptured abdominal aortic aneurysms. The mean age was 69.8 years. The overall death rate was 49.4%. The most significant predictors of death were an intraoperative urine output under 100 ml, systolic blood pressure less than 90 mm Hg on admission or in the operating room, cardiac arrest and a history of collapse. Discriminant analysis correctly classified 90% of the survivors and 84% of the nonsurvivors. Aneurysm size was documented in 133 cases; the average diameter was 8.78 cm, and 13 (10%) of the aneurysms were smaller than 6.0 cm. A correct diagnosis was made preoperatively in 46% of these 13 cases compared with 77% overall (p less than 0.05), and the time from arrival to transfer to the operating room was 6.71 versus 2.37 hours (p less than 0.05). The death rate for patients who had the small aneurysms was 77% versus 45% for those with larger aneurysms (p less than 0.06). This study confirms the continuing poor results after repair of ruptured abdominal aortic aneurysms. A subset of patients having small aneurysms (less than 6.0 cm) require an aggressive approach to diagnosis and treatment.

Aged↗

Comparison of left ventricular function and myocardial perfusion for evaluating perioperative cardiac risk of abdominal aortic surgery.

The measurement of left ventricular function by gated blood pool scanning and of myocardial perfusion by dipyridamole thallium imaging were compared in a prospective study of patients who had abdominal aortic aneurysm or aortoiliac occlusive disease to determine which measurement was the better predictor of postoperative cardiac complications. Sixty-six men and 19 women (mean age 67 years) underwent both tests before admission for surgery. Fifty-six had repair of an abdominal aortic aneurysm, and 29 had reconstruction for aortoiliac occlusive disease. In 17 patients the left ventricular ejection fraction was less than 50%. Dipyridamole thallium imaging was positive, showing redistribution, in 45 patients. Postoperative cardiac complications occurred in 33 patients. The sensitivity of dipyridamole thallium imaging (91%) was significantly (p less than 0.01) greater than that observed with gated blood pool scanning (27%). However, the specificity of gated blood pool scanning (85%) was similar to that of dipyridamole thallium imaging (71%). Diagnostic accuracy was greatest with dipyridamole thallium imaging (79% versus 62% [p less than 0.02]). Dipyridamole thallium imaging is superior to gated blood pool scanning for perioperative evaluation of vascular surgical patients.

Aged↗

Popliteal aneurysms: an index of generalized vascular disease.

A review of 59 popliteal aneurysms in 38 patients seen over 10 years revealed that 34 (58%) aneurysms were symptomatic. Symptoms included gangrene (15%), ischemia due to thrombosis (38%) and embolism (5%). Patients with unilateral aneurysms (45%) were a median of 7 years younger than those with bilateral lesions (55%). The latter group had more frequent manifestations of occlusive disease, which included previous myocardial infarction, coronary artery bypass grafting and stroke. They also had more concomitant aneurysms, those of the abdominal aorta and femoral and iliac arteries being the most common. Management consisted of bypass grafting in 34 limbs and immediate amputation in 9; 16 inoperable limbs remained viable. At last follow-up (median 32 months) or time of death, 30 of 34 grafts were patent. Four grafts occluded, one perioperatively and the others at 4, 5, and 32 months respectively, resulting in two amputations. The cumulative patency rate in the asymptomatic group was 94% compared with 81% in the symptomatic group. These data illustrate that patients with popliteal aneurysms may have associated vascular disease, the likelihood of which is increased when aneurysms are bilateral.

Aneurysm↗

A comparison of dipyridamole-thallium imaging and exercise testing in the prediction of postoperative cardiac complications in patients requiring arterial reconstruction.

The individual and combined predictive values of dipyridamole-thallium imaging and exercise testing were compared in a prospective study of 70 patients who had abdominal aortic aneurysms or aortoiliac occlusive disease that required surgical repair. All patients were evaluated clinically by the same cardiologist and had exercise stress testing and dipyridamole-thallium imaging before admission for surgery. Ten patients were excluded from the study because they had evidence of severe ischemia when tested (ST segment depression greater than 2 mm on exercise testing, severe multivessel disease on thallium imaging). The remaining 60 patients were operated on (abdominal aortic aneurysm repair, 40; aortobifemoral repair, 17; femorofemoral graft, 3). The test results were withheld from the surgeon, anesthetist, and cardiologist before surgery. A total of 22 patients experienced major cardiac complications postoperatively (acute pulmonary edema, 17; acute myocardial, infarction, 5; cardiac death, 2). Thallium imaging showed myocardial ischemia in 31/60 patients. Exercise testing was positive (greater than or equal to 1 mm ST segment depression) in 10/60 patients. Dipyridamole-thallium imaging with a high sensitivity and reasonable specificity is the initial test of choice. Exercise testing is a poor screening test because of its low sensitivity. The combination of the two tests gives the highest positive predictive value and the greatest likelihood ratio. Thus patients assessed initially and found to have positive thallium scan results may be further stratified by exercise testing.

Adult↗

Abdominal aortic aneurysm: consequences of a positive family history.

To assess the prevalence of coexisting abdominal aortic aneurysm (AAA) within certain families, a retrospective review was carried out of patients who had undergone AAA repair over a 5-year period. Contact was made with 305 families (52%) and a positive history of an affected, first-degree relative was obtained in 34 (11%). A known AAA was reported to affect approximately 20% of siblings at risk when the proband had an affected parent or sibling. Siblings of patients with an affected first-degree relative represent a high-risk group that may benefit from a screening program for earlier detection and elective management of AAA.

Aorta, Abdominal↗