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Biomedical subjects

J M Edwards

Publications and source records attributed to J M Edwards.

At least 73 records · Page 4Linked to original sources
PubMed1993

Correlation of North American Symptomatic Carotid Endarterectomy Trial (NASCET) angiographic definition of 70% to 99% internal carotid artery stenosis with duplex scanning.

PURPOSE: The North American Symptomatic Carotid Endarterectomy Trial (NASCET) has thus far demonstrated conclusive benefit for carotid endarterectomy for patients with symptomatic 70% to 99% internal carotid artery (ICA) stenosis. In the NASCET, ICA stenosis was classified angiographically: % ICA stenosis = (1 - [narrowest ICA diameter/diameter normal distal cervical ICA]) x 100%. However, widely used duplex scan criteria for ICA stenosis correlate with different angiographic categories of high-grade stenosis (50% to 79%, > 80%) and were developed on the basis of estimated bulb diameter. We therefore blindly evaluated with separate observers carotid angiograms from 100 patients who also underwent carotid duplex scanning in our vascular laboratory. METHODS: "Angiographic stenosis" was calculated as in NASCET. Duplex scan measurements of ICA peak systolic velocity (PSV), ICA end-diastolic velocity, and the ratio of ICA PSV to common carotid artery (CCA) PSV were analyzed for sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy to identify a 70% to 99% ICA stenosis. RESULTS: Analysis of the data revealed that an ICA PSV/CCA PSV ratio of 4.0 provided the best combination of sensitivity (91%), specificity (87%), positive predictive value (76%), negative predictive value (96%), and overall accuracy (88%) for detection of a 70% to 99% stenosis. CONCLUSION: We conclude duplex scan determination of 70% to 99% stenosis as defined in the NASCET requires the adoption of duplex criteria modified from those in current use in most vascular laboratories.

Angiography, Digital Subtraction↗
PubMed1993

Surgery for chronic lower extremity ischemia in patients eighty or more years of age: operative results and assessment of postoperative independence.

PURPOSE: Revascularization for chronic lower extremity ischemia (CLEI) in patients 80 or more years of age is controversial. High operative mortality, short remaining life span, and nonambulatory nursing home existence are cited as frequent outcomes in this patient group. Despite these considerations we have maintained an aggressive policy of lower extremity revascularization in functional and potentially functional patients 80 or more years of age with limb-threatening ischemia or claudication sufficient to threaten their independence. METHODS: The records of all patients 80 or more years of age who underwent lower extremity revascularization for CLEI from 1981 through 1991 were reviewed. Patients were evaluated for surgical indication, perioperative mortality, late survival, graft patency, and limb salvage. In addition, the patient's preoperative and postoperative independence determined by living situation (home versus nursing home) and ambulatory status were examined. RESULTS: During the period reviewed 88 patients 80 or more years of age underwent 95 arterial reconstructions for CLEI; 95% for limb salvage and 5% for short-distance claudication. There were 81 (85%) infrainguinal bypasses and 14 (15%) extra-anatomic bypasses, 5 of which also included a simultaneously placed infrainguinal bypass. The perioperative mortality rate was 6%. Mean hospitalization was 18 days (range 6 to 62). The 1- and 3-year primary graft patency rates were 88% and 66%, limb salvage rates 94% and 91%, and patient survival rates 73% and 51%, respectively. One year after operation 88% of patients were ambulatory, 85% were living at home, and 80% were both living at home and ambulatory. At 3 years these results were 86%, 76%, and 71%, respectively. Of the patients living at home and ambulatory before operation, 100% and 84% of survivors were still living at home and ambulatory 1 and 3 years after operation. Of patients living at home who had late graft occlusions, 67% required amputation and subsequent nursing home placement. CONCLUSION: Although survival in this group is predictably lower than that of age-matched control subjects, octogenarians have satisfactory 1- and 3-year graft patency, limb salvage, and functional results. Revascularization for CLEI in patients 80 or more years of age is appropriate and results in maintenance of independent living in a large majority.

Activities of Daily Living↗
PubMed1992

A preliminary study of the role of duplex scanning in defining the adequacy of treatment of patients with renal artery fibromuscular dysplasia.

Renal artery fibromuscular dysplasia is a well-known cause of hypertension whose presence is confirmed by its typical arteriographic appearance. The functional significance of these lesions is often difficult to determine, particularly when both renal arteries are involved. Duplex scanning has been shown to be accurate for the detection of renal artery stenosis and estimation of the degree of narrowing. To test whether duplex scanning results after intervention correlate with clinical outcome, we reviewed the studies on nine patients with renal artery fibromuscular dysplasia who had been treated by either angioplasty or surgery. A total of 18 arteries were treated. Fourteen of the 18 treatments were successful as measured by a reduction in blood pressure and antihypertensive drugs. In four instances treatment was unsuccessful. For those patients who had clinical improvement, the hemodynamic parameters from the renal artery also improved. In the patients for whom treatment failed, the velocities recorded from the site of narrowing did not improve after intervention. Thus it appears that duplex scanning along with the clinical results may be used to document the basis for failing to improve after treatment be it angioplasty or operation.

Adult↗
PubMed1992

Intraabdominal paraanastomotic aneurysms after aortic bypass grafting.

Although the reported incidence of intraabdominal paraanastomotic aneurysms after abdominal aortic bypass grafting ranges from 1% to 15%, the true incidence is unknown because few studies have used routine, serial radiographic or sonographic imaging studies. Since July 1, 1988, we have used yearly abdominal sonography examinations to monitor our patients with aortic grafts. In the first 33 months we studied 138 patients. Medical records of 111 of these were available for review and form the basis of this report. Eleven patients (10%) were found to have intraabdominal paraanastomotic aneurysms ranging in overall size from 4.1 to 6.2 cm (mean, 5.0 +/- 0.7 cm). The mean time between operation and detection of an aneurysm was 144 +/- 101 months (range, 8 to 336 months). Three paraanastomotic aneurysms occurred within 3 years of operation, and the remaining eight occurred late (7 to 28 years). By life-table analysis, the incidence of paraanastomotic aneurysms was 27% at 15 years. Paraanastomotic aneurysms were classified as either pseudoaneurysms (presumed disruption of the anastomotic suture line, n = 7) or as true aneurysms (widening of the adjacent aorta, n = 4). True aneurysms occurred only after repair of an abdominal aortic aneurysm, whereas pseudoaneurysms were more frequent after bypass for occlusive disease. The finding of paraanastomotic aneurysms in 10% of our patients supports the use of yearly sonography for routine follow-up after aortic grafting.

Aged↗
PubMed1991

Role of duplex scanning for the detection of atherosclerotic renal artery disease.

To assess the accuracy of renal artery duplex scanning for the purpose of diagnosing atherosclerotic renal artery stenosis, we compared the findings of renal arteriograms to the results of duplex scanning in 41 patients. Using an increase of renal artery peak systolic flow velocity of greater than 180 cm/sec, duplex scanning was able to discriminate normal from diseased renal arteries with a sensitivity of 95% and a specificity of 90%. Using the principle that blood flow velocity across a stenosis is roughly proportional to the degree of stenosis, it appeared that a ratio of the peak velocity in the renal artery to the aorta (RAR) of greater 3.5 predicted a greater than 60% diameter reduction of that renal artery, which is felt to be a significant stenosis. Forty-eight vessels were classified as having a greater than 60% diameter reduction by arteriography. Using the RAR of greater than 3.5, duplex scanning agreed in 44 renal arteries (sensitivity 92%). In the 26 renal arteries where arteriography showed a less than 60% diameter reduction, duplex scanning agreed in 16 vessels and correctly detected a focal narrowing in nine of the remaining ten vessels. Ten of 11 occluded renal arteries were correctly identified by duplex scanning. Duplex scanning determined the location of the renal artery lesion with an accuracy of 95% (kappa 0.74). Since duplex scanning can accurately demonstrate and locate focal renal artery stenosis, we believe it may become an accurate screening test for renovascular hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

The role of duplex scanning in the selection of patients for transluminal angioplasty.

As part of our initial evaluation to determine whether patients with lower extremity ischemia are candidates for intervention, arterial duplex examinations are performed in the noninvasive vascular laboratory. Patients with isolated short stenoses on the duplex examination are referred for transluminal angioplasty. One hundred thirty-four arteriograms were performed for ischemic peripheral vascular disease in 122 patients between July 1987 and March 1990. One hundred ten (82%) of the arteriograms were preceded by a lower extremity arterial duplex evaluation. Fifty cases (45%) were scheduled for transluminal angioplasty based on the findings of the duplex examination. Transluminal angioplasty was performed in 47 of 50 cases (94%). No significant differences in age, sex, or diabetes were found between the patients who were referred for transluminal angioplasty and those who were not. These data demonstrate that duplex scanning of the lower extremities allows the detection of lesions that will be amenable to transluminal angioplasty. We think that duplex scanning should become the standard screening tool for detection of treatable lower extremity lesions.

Angiography↗
PubMed1991

Demonstration of Chlamydia trachomatis in colposcopic cervical biopsy specimens by an immunoperoxidase method.

A total of 31 cervical biopsy specimens were taken from 29 women attending a genitourinary medicine clinic, nine women (11 biopsy specimens) were known to have Chlamydia trachomatis cervicitis and 20 women were known to be free of chlamydial infection. The specimens were routinely processed to paraffin wax and stained by an anti-Chlamydia immunoperoxidase technique to localise the organisms. Of the 11 positive biopsy specimens three showed positive staining of elementary/reticulate bodies. In one case the surface endocervical cells showed large inclusions which were packed with chlamydial bodies. The diagnosis of chlamydial infection is difficult to make clinically and in routine cytological and histological specimens but immunoperoxidase staining can clearly identify C trachomatis inclusions in cervical biopsy specimens provided infection is severe.

Cervix Uteri↗
PubMed1991

A survey of female prostitutes at risk of HIV infection and other sexually transmissible diseases.

OBJECTIVE: To determine risk factors for the transmission of human immunodeficiency virus (HIV), including injecting drug use (IDU), sexual behaviour and other sexually transmissible diseases (STDs), in female prostitutes who attended the Sydney Sexual Health (previously STD) Centre. DESIGN: We surveyed by questionnaire 231 (47%) of 491 female prostitutes who visited the Centre over a 19 month period from 1986 to 1988. All were tested for HIV antibody. MAIN OUTCOME: All the women were seronegative for HIV but a number of major risk factors for infection were identified. RESULTS: Seventeen of 26 (65%) current injecting drug users had shared needles in the previous 6 months. Nineteen per cent of those surveyed had bisexual non-paying partners and 21% had partners who injected drugs. Sixty nine per cent always used condoms for vaginal intercourse with paying clients, but they were rarely used with non-paying partners. Condom use was also rare for anal intercourse with clients and/or partners by those (18%) who practised it. Seventeen per cent used condoms alone for contraception and 48% relied on oral contraceptives. We found a reduction in gonorrhoea, herpes and trichomoniasis when compared with a 1985 study conducted at the same Centre. However, there was an increase in reported abnormal cervical cytology. CONCLUSION: In spite of behaviour change by some, there are still many women working as prostitutes in Sydney who remain seriously at risk of HIV infection. We recommend more widespread use of barrier methods of contraception, intensified efforts to prevent the sharing of intravenous needles, closer monitoring of the health of prostitutes, and scientific study of their paying and non-paying sexual partners.

Adolescent↗
PubMed1990

The frequency histogram--a new method for the evaluation of laser Doppler flux motion.

A digital filter system (DFS) was implemented to describe the frequency components of laser Doppler signals. The DFS calculates a frequency histogram on the basis of the prevalence of a certain frequency band during the sample period. This approach seems to be more suitable for the detection of low-power small-amplitude flux motion components recorded by laser Doppler as compared to the commonly used fast Fourier algorithm. Fourier analysis provides an amplitude-relevant frequency spectrum which may overlook relevant frequency components with small amplitude due to low power or short duration. DFS allows better detection of such signals as demonstrated by the initial clinical results of this study evaluating flux motion on the feet of 4 healthy controls and 10 patients with peripheral arterial occlusive disease. Three frequency components are easily distinguished corresponding to low (3.6 +/- 1.5 cycles/minute) and high (18.6 +/- 4.5 cycles/min) frequency flux motion and the pulsatile waves due to cardiac action.

Aged↗
PubMed1990

Surgical treatment of distal ulnar artery aneurysm.

In the past 7 years, we have encountered six patients with finger ischemia as a result of digital artery occlusion associated with seven distal ulnar artery aneurysms. Our experience with the management of these patients forms the basis of this report. All patients were men, with a mean age of 29 years, and all experienced repetitive trauma to the involved upper extremity. Each patient presented with the acute onset of cool and painful digits, with no previous history of cold sensitivity or Raynaud's syndrome. None of the patients had any serologic or clinical evidence of autoimmune disease. Angiography revealed occlusion of the ulnar artery on the affected side in two patients and patent ulnar artery aneurysms in the remaining five patients. There was occlusion of multiple common and proper digital arteries in all patients. One patient with bilateral ulnar artery aneurysms underwent operative repair consisting of aneurysm excision and replacement with autogenous vein grafts from the lower extremity. All patients have improved symptoms, and the grafts remained patent over a mean follow-up of 24 months (range: 13 to 57 months). Based on these results, we recommend that excision and grafting be considered for patients with symptomatic patent ulnar artery aneurysms. Selected patients with thrombosed aneurysms with ongoing digital ischemia may also benefit from surgical intervention.

Adolescent↗
PubMed1990

Present status of reversed vein bypass grafting: five-year results of a modern series.

From January 1980 through December 1988, 564 limbs in 434 patients were treated for infrainguinal arterial ischemia. Of these, 516 limbs in 387 patients underwent reversed vein bypass grafting. The remainder were treated by primary amputation (11 limbs, 1.9%) or by prosthetic bypass (37 limbs, 6.4%). The indications for operation were limb salvage in 80% of limbs and claudication in 20%. Adequate ipsilateral greater saphenous vein was available for 285 (55%) grafts, with reversed vein bypass achieved in the other 231 operations by use of distal graft origins (151 grafts), use of alternate vein sources (120 grafts), and splicing of venous segments (81 grafts). Seventy-six grafts (15%) were to the above-knee popliteal artery, 199 grafts (37%) were to the below-knee popliteal artery, and 241 grafts (47%) were to infrapopliteal arteries, 26 of which (11%) were to inframalleolar arteries. The primary and secondary patencies for all grafts at 5 years were 75% and 81%, respectively. Grafts to infrapopliteal arteries had significantly worse primary patency (69%) at 5 years than did grafts to the popliteal artery (77%, above knee; 80%, below knee) and grafts formed of adequate ipsilateral greater saphenous vein had significantly better primary patency (80%) than did grafts performed when this conduit was not available (68%). Secondary patency of all graft categories ranged from 76% to 85%, and there were no significant differences regardless of site of distal anastomosis, source of venous conduit, or site of graft origins. We prefer the use of reversed vein bypass grafting for lower extremity revascularization both because of the excellent patency results and because the technique can be applied to the larger number of patients in our practice who lack intact ipsilateral greater saphenous vein, in contrast to in situ vein bypass procedures.

Amputation, Surgical↗
PubMed1990

The effects of cooling on human saphenous vein reactivity to adrenergic agonists.

Human saphenous veins were obtained at surgery and assayed immediately (n = 10). The veins were cut into rings, suspended in organ chambers, and connected to force transducers for the recording of isometric tension. One ring served as control whereas others were treated with the alpha 1-adrenoceptor antagonist prazosin (3 X 10(-7) mol/L), or the alpha 2-adrenoceptor antagonist rauwolscine (10(-7) mol/L). In quiescent rings cooling from 37 degrees C to 24 degrees C had no significant effect. Norepinephrine (10(-8)-10(-5) mol/L) caused concentration-dependent contractions with an EC20 (-log concentration of norepinephrine required to induce contractions 20% of maximal) = 6.97 +/- 0.10. The contractions were inhibited by prazosin (EC20 = 5.89 +/- 0.17, p less than 0.001) and rauwolscine (ED20 = 5.78 +/- 0.11, p less than 0.001). In control rings cooling potentiated contractions evoked at concentrations of norepinephrine below 10(-6) mol/L and inhibited those at higher concentrations. In rings treated with alpha-antagonists cooling depressed the maximal contractile responses. Contractions to the alpha 1-agonist, phenylephrine (10(-7)-10(-4) mol/L), were inhibited by cooling, whereas those to the alpha 2-specific agonist B-HT 920 (10(-7)-10(-4) mol/L) showed a pattern similar to that seen with norepinephrine. The data indicate that the human saphenous vein possesses both alpha 1- and alpha 2-adrenoceptors postjunctionally, and that both contribute to contractile responses. Cold augments saphenous vein reactivity to norepinephrine by an apparent increase in the responsiveness of alpha 2-adrenoceptors to agonists. The relationship between temperature and adrenoceptor responsiveness may be of pivotal importance in defining the mechanism of cold-induced vasospasm.

Cold Temperature↗
PubMed1989

Ploidy as a prognostic indicator in oesophageal squamous carcinoma and its relationship to various histological criteria.

One hundred surgically resected squamous cell carcinomas of the oesophagus were studied retrospectively to assess the significance of DNA aneuploidy as determined by flow cytometry using paraffin-embedded tissue. DNA aneuploidy was not an independent prognostic indicator but was found to be associated with tumour necrosis and host/tumour interface fibrosis. When tumours confined to submucosa or muscle wall were assessed, diploid tumours had a poorer survival rate than DNA aneuploid tumours. Other histological variables studied were tumour differentiation, depth of infiltration, glandular and small cell differentiation, lymphatic and vascular spread and host inflammatory response. These failed to show any significant association with ploidy.

Adult↗