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Biomedical subjects

L Pedrini

Publications and source records attributed to L Pedrini.

At least 37 records · Page 2Linked to original sources
PubMed1994

Failure of thrombolytic therapy to improve long-term vascular patency.

PURPOSE: Few data are available on long-term follow-up of arterial segments subjected to thrombolysis. We reviewed all cases of vascular occlusion treated with urokinase to identify early success and determine the influence of postlysis intervention and the nature of the thrombosed segment (i.e., artery vs graft) on long-term patency. METHODS: Data on 134 cases (58 arteries, 76 grafts) treated with high-dose urokinase infusion in the lower limbs over a 7-year period were analyzed. Limbs were divided into five groups on the basis of therapy after lytic infusion to determine long-term efficacy: group I, success with no additional therapy; group II, percutaneous angioplasty alone; group III, limited surgical procedure (operative angioplasty, jump graft); group IV, extensive procedure (new bypass); and group V, revascularization after lytic failure. Long-term results were assessed by life-table analysis and groups compared by log-rank test (Mantel-Haenszel). RESULTS: Initial patency was established in 87 (64.9%) of 134 cases with 5 deaths (3.7%), 11 amputations (8.2%), and 16 complications (11.9%). Follow-up was available in 68.6% of cases for a mean of 10.9 months. No difference was seen between grafts and native arteries. Patency was analyzed at 6, 12, 18, and 24 months. The 24-month patency rate after lysis alone (group I-25.9%) was inferior (p < 0.05) to results after lysis and any subsequent intervention (groups II, III, and IV). The type of intervention did not influence subsequent patency. Twenty-four-month patency of procedures performed after failed thrombolysis (group V, 41.4%) was not different from those after successful lysis (groups I to IV). Twenty-four-month patency in groups II and III (minor interventions, 62.9%) was not significantly different from that of groups IV and V (major interventions, 53.2%) (p > 0.25). CONCLUSIONS: Operative intervention is required to produce long-term arterial patency, even after successful thrombolysis. No statistically significant benefit of thrombolysis on vascular patency was seen in our series.

Angioplasty↗
PubMed1994

Left-side inferior vena cava and inflammatory abdominal aortic aneurysms: a case report.

The incidence of isolated left-side inferior vena cava ranges from 0.2-0.5%. This anomaly is associated infrequently with an abdominal aortic aneurysm. A case is reported of left-side inferior vena cava associated with a symptomatic, 5-cm inflammatory abdominal aortic aneurysm. Preoperative computed tomography showed a perianeurysmal mantle strongly adherent to a left-side inferior vena cava. This report is the first of an infrarenal inferior vena cava anomaly associated with an inflammatory abdominal aortic aneurysm. The technical details required to perform the aortic reconstruction via a transperitoneal approach are described and discussed.

Aortic Aneurysm, Abdominal↗
PubMed1994

Abdominal aortic hypoplasia: clinical and technical considerations.

Hypoplasia of the distal abdominal aorta, first described by Quain in 1847, is rarely associated with atherosclerotic occlusive disease. The condition usually occurs early in life; the principal clinical features are hypertension and arterial insufficiency of the lower extremities which is often well tolerated. Some 20 patients had operations for abdominal aortic hypoplasia; 16 underwent prosthetic reconstruction and four had aortoiliac endarterectomy with angioplasty. Reconstructive techniques were influenced by narrow renal arteries and by the presence of extensive atheroma. The long-term prognosis is often poor, especially in patients with extensive disease.

Adult↗
PubMed1994

Late occlusion of aortofemoral bypass graft: surgical treatment.

Surgical treatment for graft thrombosis is often difficult and its outcome is complicated by a high incidence of rethrombosis. The records of 803 patients (1261 limbs) treated with aortofemoral bypass graft for peripheral vascular disease were reviewed. Among these, 71 patients (63 men and eight women with a mean age of 60.2 years) needed an overall number of 125 reoperations. The mean follow-up was 6.3 years. Smoking was significantly higher in these patients compared with those who were not reoperated on. Intimal hyperplasia was the most common lesion responsible for graft thrombosis. Before 'redo' surgery 20 patients with recent thrombosis received thrombolytic treatment; one was subsequently treated with percutaneous transluminal angioplasty and the others underwent reoperation. The best patency rates were achieved with reconstruction of the distal anastomosis with a graft interposition or with a patch angioplasty. Isolated thrombectomy was complicated by early rethrombosis in 53.3% of cases. The overall amputation rate was 14%, the operative mortality rate 5.6%, and the incidence of complications 16.8%. At follow-up a cumulative secondary patency rate of 81.7% at 5 years (74.5% at 10 years), a limb salvage rate of 80.5%, and a survival rate of 89.2% at 10 years were recorded. It is concluded that the only indications for redo surgery following graft thrombosis are severe limb ischaemia or disabling claudication.

Adult↗
PubMed1994

Ischemia-reperfusion syndrome: an alternative experimental model.

OBJECTIVE: To design an alternative experimental model of ischemia-reperfusion syndrome. Our model mimics the clinical pattern of the syndrome and also assesses the efficacy of therapeutical protocols. EXPERIMENTAL DESIGN: Ischemia was induced under general anaesthesia in the posterior limbs of 10 sheep by occluding the aorta and vena cava by means of two-way balloon catheters. Ischemia was stopped after 4 hours and blood and histologic parameters determined in the first three hours of revascularization. The animals were divided into three groups: a group of 3 sheep in which a sham operation was performed; a control group (5) to assess the efficacy of induced ischemia; the third group (5) to determine the effect of antioxidant and membrane protective drugs to assess the reliability of the model to study the ischemia-reperfusion syndrome. RESULTS: At the end of ischemia, skin temperature was decreased (p < 0.04) both in control and treated groups, pH decreased significantly soon after reperfusion in the control group (p < 0.04). Reperfusion in control sheep, compared with treated animals, was followed by a significant increase in CPK blood levels (p < 0.009), related to marked muscle damage, in particular after reperfusion. Tissue damage detected at TEM was less severe in treated animals. CONCLUSIONS: This model is an effective experimental strategy and a means of assessing preventive treatment.

Animals↗
PubMed1993

Intraoperative cerebral monitoring in carotid surgery.

We have used and studied intraoperative cerebral monitoring in order to prevent intraoperative and early postoperative cerebral ischaemia. The techniques examined have included stump pressure measurement, the evaluation of somatosensory evoked potentials (SEPs) and completion intraoperative angiography. Stump pressure was measured in 920 patients and a safety level of 50 mmHg confirmed. Below this value, non-shunted patients were three times more likely to have cerebrovascular accident (CVA). SEPs were prospectively monitored in 72 patients and a mean decrease of N20-P25 in complex amplitude was seen in patients with a positive CT scan. In particular, pathological SEPs were found in 53% of patients with a positive CT scan, and in 54% of those with a contralateral carotid occlusion. In these patients, the N20-P25 amplitude fell progressively in the first 4 min. Using SEPs, the indication for shunting was 42% lower than with the measurement of back pressure and no patient with normal SEPs had a postoperative neurological deficit. The data obtained under local anaesthesia in 25 patients monitored by stump pressure and SEPs did not give better results. Intraoperative completion angiography performed routinely since 1978 has made it possible to reduce the need for immediate reoperation from 10-2%.

Blood Pressure↗
PubMed1993

Prevention of reperfusion syndrome in acute muscular ischaemia with free radical scavengers and membrane-protecting compounds: an experimental study.

The prevention of oxidant-induced damage following reperfusion was experimentally evaluated. Two pharmacological regimens containing different combinations of antioxidant factors and membrane-stabilizing compounds, such as alpha-tocopherol (vitamin E), methionine, dexamethasone, mannitol and cysteine, were administered. The reduced/oxidized glutathione (GSH/GSSG) ratio in muscle was used to evaluate oxidative stress. Ischaemia was induced by occluding the aorta and the inferior vena cava with an irrigation-occlusion catheter. After 4 h of ischaemia, five sheep were reperfused without any treatment (control group) and five treated with an endoaortic bolus administered at declamping (treatment 1). In five other sheep, treatment started during ischaemia (treatment 2). Ischaemia and, in particular, reperfusion significantly reduced the muscle GSH content, compared with the basal value in the control group; thus the GSH/GSSG ratio decreased significantly in the control group from 10.5(2.2) (mean(s.e.) basal value) to 0.687(0.3) at reperfusion (P < 0.009). Both treatments 1 and 2 significantly prevented a reduction in GSH content induced by reperfusion following ischaemia; the GSH/GSSG ratio (10.5(2.2) basal value) increased to 19.67(4.6) with reperfusion in the treatment group 1, mainly because of a lower decrease of GSH and a lower level of GSSG while it did not change in treatment group 2 (10.7(5.0)). Levels of creatine phosphokinase did not change in the treated groups, although they increased significantly in the control group (P < 0.006). Although oxidative stress is not the only cause of damage in revascularization, this study confirms the protective ability of treatment with free radical scavengers and membrane-stabilizing compounds.

Animals↗
PubMed1993

[Carotid stenosis associated with contralateral carotid occlusion].

Carotid surgery in patients with carotid stenosis and contralateral occlusion is generally followed by a higher operative morbidity and mortality-rate than patients with monolateral stenosis. To verify our experience, the records of 167 patients affected with internal carotid stenosis with contralateral occlusion operated on between 1978-1991 were reviewed. They were 139 males and 28 females with a mean age of 62.3 years, and represent the 16% of the patients operated on for carotid lesion in the same time period. The indications for surgery were TIA or RIND in 52 patients, minor stroke or stroke in 9, non hemispheric symptoms in 19; 22 patients were asymptomatic, and 75 presented symptoms unrelated to the operated stenosis. The operative morbidity and mortality-rate of the whole sample were: stroke-rate 4.8%, mortality-rate 3% and cumulative stroke + mortality-rate 5.4%. In particular the operative risk was higher in patients operated on for stroke or for vertebro-basilar symptoms, while patients with reversible symptoms and asymptomatic patients had a significant lower stroke-rate both in the post-operative period and in the follow-up (p < 0.02). Patients operated on for completely asymptomatic lesions and for contralateral borderline symptoms had no operative symptoms. Relationships between operative complications and pre or per-operative monitoring have been analyzed; our results suggest a more extensive use of intraluminal shunt and an operation under general anaesthesia in patients with ischemic areas shown by a pre-operative SPECT or with a cerebral infarct even if SPECT monitoring does not suggest its use.

Arterial Occlusive Diseases↗
PubMed1993

Natural history of patients with carotid stenosis waiting for surgical treatment.

BACKGROUND AND PURPOSE: The natural history of carotid lesions has generally been evaluated in anedoctal series or in clinical trials. The purpose of this study was to evaluate clinical and pathological modifications linked to an increasing waiting list in our region and the related medico-legal implications. METHODS: Neurological symptoms that occurred during the waiting period were evaluated in 282 out of 491 patients placed on the waiting list for a carotid stenosis less than 80% or without an unstable plaque. The other 202 patients cancelled their booking. Progression of carotid disease was evaluated by duplex scanning in 116 patients who had a duplex evaluation in our Department both at booking and at the time of operation. RESULTS: The incidence of stroke in a mean waiting period of 8.9 months was 2.6% in symptomatic patients and 1.5% in asymptomatic, respectively; 39 (13.8%) patients experienced an ipsilateral TIA and 4.2% a carotid thrombosis (25% of which symptomatic). The crude mortality-rate was 2.4% with a 1% of related deaths. The cumulative actuarial hard end points rate (stroke, carotid thrombosis and related death) was 7.8% at 12 months and 19.8% at 18 months. CONCLUSIONS: This study gives us data about the natural history of carotid stenosis in our country. The high morbidity and mortality-rate related to this lesion and particularly their occurrence within the first 3 months stress the urgency of treatment, and of the planning of specialized Departments in relation to the real incidence of the pathology in order to avoid medico-legal consequences.

Aged↗
PubMed1992

Local haemofiltration with free radical scavenger treatment during revascularisation of severe muscular ischaemia induced in sheep limbs.

Many treatments have been proposed for the prevention of the revascularisation syndrome following embolectomy or thrombectomy in patients with severe ischaemia. These include the administration of diuretics, bicarbonate, buffer solutions, free radical scavengers, washing out the venous blood from the ischaemic leg, or systemic dialysis. The aim of our study was to investigate the effect of combining haemofiltration with a treatment using compound oxy-radical scavengers in order to prevent or to reduce the appearance of the revascularisation syndrome. The study was performed on 13 sheep. Eight animals underwent 4 h of aortic and vena cava occlusion using irrigation-occlusion catheters, followed by normal reperfusion (control group). Five sheep underwent the same period of ischaemia, followed by 1 h of local haemofiltration and re-oxygenation and 2 h of normal revascularisation. The priming solution for the ECC circuit consisted of 500 ml of 20% mannitol and 500 ml of 18/1000 HCO3- contained: superoxide dismutase (150,000 I.U.), methylprednisolone, 1 g, and heparin, 10,000 I.U. After the 3rd h of ischaemia, 2.1 g of acetate alpha-tocopherol (30 mg kg-1) were injected i.m. The treatment produced good protection against oxidative stress, shown by an increase in the glutathione ratio (GSH/GSSG), and reduced muscular damage, confirmed by a moderate increase in creatine phosphokinase (CPK) levels (significantly higher in the control group). Diuresis was significantly higher in the treated group, and the acid-basic and potassium balance returned to normal more rapidly. Our data suggest that this combined treatment could be effective in the prevention of the ischaemia-reperfusion syndrome.

Animals↗
PubMed1992

Immunization and vaccination protocol in hemodialysis patients with naturally acquired hepatitis B antibody.

Long-term behavior of naturally acquired anti-HBs antibody was tested every 6 months for 3 years in 22 dialysis patients. Fifteen of them maintained protective levels throughout follow-up (102 and 85.5 mUI/ml at the beginning and the end, respectively). Seven of them became anti-HBs and were submitted to a 40-micrograms booster injection of hepatitis B vaccine. Seroconversion was observed in 6 of 7 patients (85.7%) with a mean anti-HBs titer of 90.4 and 47.3 mUI/ml after 3 and 6 months, respectively. Protective anti-HBs level may be maintained longer in patients with natural immunity than in HBsAg-negative vaccinated subjects. Effectiveness of a reduced vaccination protocol in patients who have lost their natural immunization should be confirmed with further studies.

Adult↗
PubMed1990

Adequate sodium balance and cardiovascular stability.

To evaluate the sodium balance in haemodialysis and haemodiafiltration a computerised model has been developed, which calculates net sodium balance from the infusive, diffusive, and convective sodium fluxes for each minute of treatment, updating the value of plasma water ionised sodium concentration at each step. Using this model and assuming constant body-weight, treatment time, and net ultrafiltration, different haemodialysis and haemodiafiltration treatments, with different dialysate sodium concentrations, sodium infusions, and pre-treatment plasma water sodium concentrations were simulated. The results show that a less negative sodium balance is almost always obtained during haemodiafiltration than in haemodialysis, when using the same dialysate sodium concentrations. Therefore, since sodium is an important factor in cardiovascular stability, it is necessary to match sodium balance with other operational parameters when comparing haemodiafiltration with haemodialysis.

Cardiovascular System↗
PubMed1989

Traumatic amputation of the upper limb: replantation of the arm.

From 1970 to 1985, 13 patients were treated as a result of an upper limb traumatic sub-amputation. Three of them were younger than 15 years and another one was only 3 years old at the time of the trauma. All the elements involved in the treatment of the lesions are described. When it was possible, an end-to-end anastomosis was used for the repair of arteries and veins. Otherwise, when the loss of tissue was marked, a saphenous vein graft was used. The fracture was treated, when possible, with an intramedullary fixation, surely less traumatizing for soft tissues than a plate. The repair of the nerve was at times simultaneous at other times delayed. The followup has shown a good functional restoration of the limb and of the joints affected by the trauma and a normal development of the patients in terms of age.

Adolescent↗
PubMed1989

Late urologic complications in aorto-iliac reconstructions.

Aortoiliac reconstructive hydroureteronephrosis after surgery may be due to an incorrect position of the .0.prosthesis, anteriorly to the ureter, to a reactive retroperitoneal fibrosis or to a sclerotic outcome caused by vessel and ureter dissection. It is important to consider the possible correlation of hydronephrosis with recurrent prosthetic infections, both as a consequence and as a pre-existing cause of the infective process itself. In the present study, 100 patients were examined, all affected with chronic peripheral obstructive arterial disease and operated on for aortoiliac reconstruction by the same surgeon. A clinical, laboratory and echographic study was performed, after a follow-up period from surgery ranging between 23 and 146 months (72 months on average). Four of them (4%) showed unilateral hydronephrosis, always asymptomatic and resulting from a retroperitoneal fibrosis. When hydronephrosis was moderate or severe, an intravenous pyelography was performed. Only one patient required ureterolysis and "wrapping" of the ureter with adipose tissue, and insertion of an indwelling ureteral catheter, due to marked hydronephrosis and a reduction in the diameter of contralateral kidney. From this retrospective study, the opportunity and the prognostic importance of a perspective study of the patients undergoing aorto-iliaco-femoral reconstruction for an obstructive or aneurysmal disease is evidenced.

Adult↗
PubMed1987

Complications following the treatment of abdominal aortic aneurysms.

The complications following the surgical treatment of 328 cases of abdominal aortic aneurysm are reported. In some cases such complications are predictable and their knowledge is useful to reduce the operative mortality. Cardiac and renal complications were more frequent in emergency, while surgical complications were mostly observed in patients with large aneurysms involving the iliac arteries. Duodenal lesions were caused in patients affected by inflammatory aneurysms. The late complications observed were: ureteral stenosis, infections, pseudoaneurysms and occlusion of a branch of the bifurcated graft.

Acute Kidney Injury↗