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Biomedical subjects

M D'Addato

Publications and source records attributed to M D'Addato.

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

Morphology of small aneurysms: definition and impact on risk of rupture.

BACKGROUND: Parietal characteristics of small aortic aneurysms predictive of increased risk of rupture are unknown. METHODS: Prospective morphologic evaluation was performed in 135 consecutive cases of small (< 5 cm) abdominal aortic aneurysm. Twelve cases (9%) were found to be ruptured and sent for emergency surgery. The remaining 123 patients were evaluated with ultrasonography, angiography, and intraoperatively during elective surgery. Ninety-six (78%) also underwent computerized tomography (CT) scanning. The evaluation assessed the thickness of the endoluminal thrombus and arterial wall as well as the presence of saccular outpouchings ("blisters"). Also noted were any areas of impending rupture, defined as discontinuity of the arterial wall with only a thrombus preventing rupture. RESULTS: Blisters were discovered intraoperatively in 12 aneurysms. Digital subtraction angiography (DSA) revealed 3 (25%) of these preoperatively. Eleven of the patients with blisters were examined preoperatively with CT scanning, which detected 3 blisters (27%). Both endoluminal thrombus and wall thickness were measurable by CT scan but not ultrasonography. The incidence of impending rupture was significantly greater in patients with blisters than in those without (71% versus 29%, P = 0.0001). The incidence of impending rupture was similar whether the amount of endoluminal thrombus was more or less than 2 cm (57% versus 40%, P = 0.386). Rupture was no more frequent when aneurysmal walls were thicker or thinner than 0.3 cm (14% versus 20%, P = 0.719). In an analysis using logistic regression, the presence of a blister was the only independent morphologic predictor of impending rupture (P = 0.001, Wald = 15). CONCLUSION: In patients with small aneurysms, increased attention should be directed to the preoperative detection of blisters.

Aged↗
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

Prevention of early graft infection with rifampicin-bonded Gelseal grafts: a multicentre experimental study.

The possibility of increasing the resistance of a synthetic vascular graft to intraoperative or immediate postoperative bacterial contamination justifies the interest in methods such as antibiotic bonding or antibiotic soaking. On the basis of this experience and with the aim of testing the efficacy of such a graft, a multicentre experimental study on sheep to compare the susceptibility to infection of Dacron Gelseal grafts (control) versus rifampicin-bonded Dacron Gelseal grafts (treated) following the intravenous infusion of 10(7)-10(8) cells Staphylococcus aureus was conducted. The grafts were implanted in both common carotid arteries of sheep. In a group of 11 animals (group A), a treated and a control graft were implanted in the same animal. In a group of four sheep (group B), only treated or control grafts were implanted in each animal. In group A, 36% of (four of 11) the treated grafts became infected versus 54% (six of 11) of the control prostheses. In group B, none of the treated grafts was infected by the inoculated pathogen, which, by contrast, infected 75% (three of four) of the controls. These observations confirm the recent interest aroused by the possibility of pretreating gelatin-coated Dacron grafts with rifampicin in the prevention of early graft infection.

Anastomosis, Surgical↗
PubMed1994

Long-term cryopreservation of autologous veins in rabbits.

This study was undertaken to determine the effect of long-term cryopreservation on graft ultrastructure and endothelial cell viability in an animal model. The jugular veins from 12 New Zealand White rabbits were excised with a 'no-touch' technique and divided into four groups: control group (fresh veins); group 1, veins cryopreserved for 1 month; group 2, veins cryopreserved for 2 months; and group 3, veins cryopreserved for 3 months. Cryopreservation was accomplished by rapid freezing (-5 degrees C s-1 to -196 degrees C) in a solution of 17.5% dimethylsulphoxide and 20% fetal bovine serum and by storage in liquid nitrogen. Veins were then implanted as a carotid autograft (three grafts/group). At the time of graft implantation a segment of the paired matched vein was perfusion-fixed and evaluated by scanning and transmission electron microscopy, whereas the remainder were subjected to endothelial cell culture techniques to determine cell viability. Autografts were removed 1 month after implantation and subjected to similar evaluations. Histological changes seen in cryopreserved veins were dependent on preservation time and included focal endothelial cell blebbing, cytoplasmic vacuolization and disruption of cell-to-cell contacts. Smooth muscle cells showed mitochondrial swelling. Patency was identical in all groups (66.6%). Explants at 1 month were similar in histological appearance to fresh veins with a smooth endothelial cell lining arranged longitudinally and intact cell junctions. Endothelial cells could be cultured from fresh veins and 1-month-old explants but not from the cryopreserved graft surface before implantation. the present technique of cryopreservation leads to some damage of graft architecture and loss of endothelial cell viability.(ABSTRACT TRUNCATED AT 250 WORDS)

Anastomosis, Surgical↗
PubMed1993

Electron microscopic and immunocytochemical profiles of human subcutaneous fat tissue microvascular endothelial cells.

The ultrastructural and immunocytochemical characteristics of microvascular cells from human subcutaneous fat tissue were studied after the addition of collagenase and Percoll density gradient, respectively. Monoclonal and polyclonal antibodies directed against antigens specific for endothelial cells (factor VIII, Ulex europaeus, CD31, and CD34), pericytes (muscle-specific actin and desmin), adipocytes (S-100 protein), and monocytes-macrophages (MAC 387 and 150.95 protein) were demonstrated by alkaline phosphatase monoclonal anti-alkaline phosphatase and protein A-gold techniques. In addition, to determine whether the harvesting method interfered with microvascular cell function, DOT immunoassays of factor VIII and CD34 were conducted on solutions recovered at collagenase incubation as well as after nylon filtration and Percoll administration, respectively. After the collagenase step, the vast majority of microvascular cells had the typical ultrastructural and immunophenotypical features of endothelial cells. In sharp contrast, following the Percoll step, only 1% to 18% of microvascular cells stained with factor VIII, Ulex europeaus, and CD31, whereas 90% of them expressed the CD34 antigen. Surprisingly, DOT immunoassay revealed the presence of factor VIII in the washing buffer recovered after the Percoll step only. Consequently the decreased expression of common endothelial cell markers (factor VIII, Ulex europaeus, and CD31) observed at the end of the cell isolation procedure was related to the adverse effects of Percoll on endothelial cell function. The CD34 surface molecule, being highly resistant, is particularly well suited for unequivocal characterization of microvascular cells as true endothelium.

Adipose Tissue↗
PubMed1993

Postoperative course of inflammatory abdominal aortic aneurysms.

Of 779 patients undergoing repair of abdominal aortic aneurysms over a 7-year period (1984-1990), 40 (5.1%) had gross features of inflammatory abdominal aortic aneurysms (IAAAs). Twenty IAAAs were assessed by CT scan preoperatively and postoperatively to evaluate the outcome of the inflammatory layer of the aneurysm in 19 cases. Complete postoperative regression was observed in nine cases (47.3%), partial regression in four (21%), and stable lesions in six (31.7%). No roentgenographic progression was found. The comparison between the roentgenologic outcome and preoperative clinical features (age, sex, erythrocyte sedimentation rate, and abdominal lumbar pain), pathologic findings, and follow-up time revealed a significant correlation (p < 0.05) between the postoperative outcome and the histologic findings in the wall (cell density and cell/fibrosis ratio). Complete regression of inflammation was observed when high cell density (16 +/- 0.7 cells/2116 microns 2) and a cell/fibrosis ratio > 1 were found. On the contrary, little or no regression of inflammation occurred when a low cell density (3.4 +/- 0.3 cells/2116 microns 2) and a cell/fibrosis ratio < 1 were found. Although it is generally thought that inflammation in IAAAs regresses after surgical repair, in our study, 31.7% of the postoperative CT scans showed no change. Histologically, the variability of morphologic aspects seemed to correlate with the relative proportions of cellular infiltrate and interstitial fibrosis in the aneurysmal wall. These proportions determine the postoperative course of the inflammation layer and, most likely, the response of the latter to steroid therapy as well.

Adult↗
PubMed1993

Content and turnover of extracellular matrix protein in human "nonspecific" and inflammatory abdominal aortic aneurysms.

Inflammatory aneurysms (IAs) have peculiar macroscopic and histological aspects which make them very different from nonspecific aneurysms (NSAs). These morphological differences seem to be determined by significant modifications of the extracellular matrix. Extracellular matrix protein component concentrations were determined biochemically in infrarenal aortic biopsies from 10 NSAs, five IAs and five non-aneurysmal aortic controls. The concentration of each wall component was expressed in % w/w (relative concentration) and in mg/wall longitudinal cm (absolute concentration) with reference to total protein recovered after hydrolysis and amino acid analysis. The biochemical results were correlated with the histological and ultrastructural features of the specimens. A significant increase in total collagen was observed in the two groups of aneurysms, with respect to the controls (NSA = 285%, IA = 382%). In contrast the 80-90% decrease in the relative concentration of elastin observed in both types of aneurysm was less marked (NSA = 55%, IA = 39%). This fall was not significant when expressed in mg/cm, although elastin derived peptide (EDP) levels in the plasma of these patients was significantly higher than in age-matched controls. The concentration of the soluble collagen fraction appeared significantly higher (Mann-Whitney, p < 0.05) in the IAs with respect to the NSAs, whilst no differences were observed between the two groups regarding the concentration of insoluble elastin and of wall and plasma EDPs. As well as providing evidence of increased elastin turnover, this study emphasises the conspicuous modifications of collagen deposition in the wall of abdominal aortic aneurysms which appeared more marked in the inflammatory group.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
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

An immunohistochemical study of inflammatory abdominal aortic aneurysms.

Seven cases of inflammatory abdominal aortic aneurysms (IAs) were studied by light microscopy, transmission electron microscopy (TEM) and immunohistochemistry. Microscopically, atherosclerosis coexisted with adventitial fibrosis and inflammation. The inflammatory component showed a follicular and a diffuse pattern. Fibrous entrapment of fatty tissue, adventitial vasculitis, neuritis were also common findings. By TEM, sparse smooth muscle cells having dilated cisternae of rough endoplasmic reticulum, large bundles of collagen fibres and oedematous, amorphous fibrillary elastin were observed. By immunohistochemistry, the follicles mostly contained CD22+ B-cells. T4- (CD2+/CD4+/CD8-), T8-(CD2+/CD4-/CD8+) cells as well as macrophages (CD4+/CD11c+) and follicular dendritic reticulum cells (DRC1+) were also detected. The monoclonal antibody Ki-67 reacted with 2-48% of germinal center cells. In the fibrous extrafollicular adventitia, actively synthesizing plasma cells prevailed over T4-cells, and macrophages. Some of the macrophages were also activated (CD4+/CD11c+/CD25+/CD30-). IgM, IgG and C3c deposits were detected in the fibrous zone, in the germinal centers, within adventitial vessels and nerves. HLA-DR antigen was diffusely expressed in cells populating both the fibrous and the follicular zones as well as in endothelial and Schwann cells. These findings suggest that IAs could develop in some individuals affected by advanced atherosclerosis of the abdominal aorta through a pathogenic B-cell response to locally presented antigens.

Antigens, CD↗
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

Aneurysmal change at or above the proximal anastomosis after infrarenal aortic grafting.

We conducted a retrospective review of all patients undergoing repair of abdominal aortic aneurysm at or above the proximal anastomosis of a previous infrarenal aortic graft between 1986 and 1991. Infected grafts and patients with suprarenal aneurysms present at the time of the original graft were excluded. Twenty-one patients, 19 men and two women, were included. The original indication for surgery was aneurysm in 14 patients and occlusive disease in seven; the mean interval from initial surgery to presentation was 10 years (range, 3 to 23 years). Twelve lesions were anastomotic false aneurysms, and nine were true aneurysms beginning in the proximal juxta-anastomotic aorta. Fourteen patients had an asymptomatic abdominal mass. Seven patients had symptoms of acute expansion (three), rupture (three), or thrombosis (one). True aneurysm and symptomatic presentation were correlated with aneurysm as the original indication for surgery. Repair was accomplished by an interpositional graft in 13 and graft replacement in eight. Seven patients required suprarenal anastomosis or renal and visceral reconstruction. Five operative deaths (24%) occurred, including two of three patients with rupture (67%) and two of seven patients (28%) in the suprarenal group. The mortality rate for elective repair with an infrarenal anastomosis was 11%. Two additional late deaths occurred during the follow-up period.

Aged↗
PubMed1991

Total excision and extra-anatomic bypass for aortic graft infection.

Reports of high mortality and amputation rates following total excision and extra-anatomic bypass for aortic graft infection have prompted the use of alternate approaches including local antibiotics, partial resection, in situ revascularization, and graft excision without revascularization. Experience with aortic graft infection was reviewed to establish current morbidity and mortality rates and evaluate our bias in favor of total excision and extra-anatomic bypass. Aortic graft infection was identified in 32 patients, 8 with aortoenteric fistulas. The mean interval between graft placement and infection was 34 months. History of groin exposure (75%) or multiple prior vascular surgery (50%) was common. Clinical signs included fever and/or leukocytosis (23 patients), false aneurysm (9 patients), graft thrombosis (6 patients), groin infection (11 patients), and gastrointestinal hemorrhage (6 patients). Microbiologic data, available in 26 patients, demonstrated gram-positive organisms in 15 patients and gram-negative in 9. Multiple organisms were seen in 11 patients. Patients were treated by partial removal with (8 patients) or without (4 patients) revascularization or total removal with (18 patients) or without (2 patients) revascularization. Revascularization was by an extra-anatomic route, either simultaneous or staged. Overall morbidity/mortality was less in the revascularized groups (p = 0.01), while late complications were seen only after partial removal (p less than 0.01). The best results were found after total excision with revascularization. No patient in this group experienced late infection or amputation during a mean follow-up of 34 months (range: 1 to 168 months). Complications after total excision and extra-anatomic bypass for aortic graft infection are lower than generally appreciated. This approach should remain the standard to which other approaches are compared.

Aged↗
PubMed1991

The cellular component in the parietal infiltrate of inflammatory abdominal aortic aneurysms (IAAA).

Eight cases of inflammatory abdominal aortic aneurysm (IAAA) (group I) and a control group of ten cases of atherosclerotic abdominal aortic aneurysm (AAA) with little or no parietal inflammatory infiltrate (group II) were studied; using light microscopy, transmission electron microscopy (TEM), and immunohistochemistry. These were used to define cell composition in the inflammatory process, the degree of cell activation and alteration of connective tissue. Large numbers of B lymphocytes were present in IAAA with preservation of the T4/T8 ratio. In addition, HLA-DR and the IL2-R antigen (specific for activated cells) were widely expressed in the cell population. The interstitial matrix contained deposits of IgG, IgM and C3c together with an increase in type III collagen and a reduction in elastin which appeared fragmented and swollen. This study, therefore, characterised the cellular component of the parietal inflammatory infiltrate in IAAA. The degree of activation shown by these cell elements and the activation of complement suggest that the relevant antigen may have been localised in the aneurysm wall at the time of observation.

Aged↗
PubMed1990

Traumatic dissection in an inflammatory aneurysm.

Primary dissections of the abdominal aorta are rare (0.4-4% of aortic dissections) and in most cases are traumatic (accidental or iatrogenic) in origin. The authors describe a case of iatrogenic dissection of the abdominal aorta following arteriography. The macroscopic and histological appearance of the aortic wall was compatible with an inflammatory aneurysm. In this type of aneurysm and in the presence of aortoiliac atherosclerosis, aortic catheterization carries a risk of aortic wall dissection.

Aortic Dissection↗