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Biomedical subjects

M D'Addato

Publications and source records attributed to M D'Addato.

At least 19 recordsLinked to original sources
PubMed1999

Immune response following fresh arterial homograft replacement for aortoiliac graft infection.

INTRODUCTION: this prospective study defines the immune response to fresh arterial homograft replacement for graft infection. MATERIALS AND METHODS: ten patients who underwent ABO-compatible homograft transplantation were studied for anti-HLA antibody production, and CD3-CD4-CD8-positive lymphocytes subset. Immunological studies were performed preoperatively, and at early (1, 3, 7 days) and late (1, 3, 6, 12, 18, 24 months) follow-up. All patients received immunosuppressive treatment with cyclosporine (1-3 mg/kg/day). Abdominal CT scans were performed postoperatively at the 1, 6, 12, 18, 24 months follow-up. RESULTS: preoperatively, antibodies could not be detected. Postoperatively, as from 1st month post-transplant, a progressive increase in % PRA was observed in all patients, up to the 12th month of follow-up. Subsequently, at 18 and 36 months, a progressive decrease in % PRA was detected. Data showed that the recipient antibodies were directed against donor-specific antigens. During the immediate postoperative period (1, 3, 7 days) CD3- and CD4-positive T lymphocytes slightly increased, whereas CD8 simultaneously decreased. Later, CD3 and CD4 progressively decreased and CD8 increased. Clinically, all patients were cured of infection at late follow-up. CT scans showed thickening of the aortic wall (range: 2.5-4.5 mm), with no signs of aneurysmal degeneration. CONCLUSIONS: fresh arterial homografts are immunogenic. Implanted homografts induce a strong anti-HLA antibody response, similar to chronic rejection, in spite of immunosuppressive treatment.

ABO Blood-Group System↗
PubMed1998

Mismatch-specific anti-HLA antibody production following aorta transplants.

In this study, we have investigated the nature and magnitude of the immunological response after implantation of human aortic segments. Five recipients of aortic segment replacement were studied for anti-HLA antibody production (specificity and Ig class), CD3, CD4, and CD8 T cell subpopulation dynamics, and aortic wall thickness. Mismatch-specific IgG antibodies to HLA class I and HLA class II antigens were first detected 1-3 months after implantation and persisted in high concentrations for at least 1 year. Computer tomography scanning showed a progressive thickness of the aortic wall. Also the absolute number of CD3, CD4, and CD8 positive lymphocytes increased progressively after implantation. In conclusion, as was observed earlier for heart valve allografts, human implanted aortic segments induce a strong anti-HLA antibody response in recipients. We speculate that these antibodies have the potential to harm the implant, for example, by having an impact on luminal narrowing.

Antibodies↗
PubMed1998

Early and long-term results in the surgical treatment of juxtarenal and pararenal aortic aneurysms.

OBJECTIVE: Surgical treatment of juxtarenal and pararenal aortic aneurysms (JPAA) provide technical problems which may influence short- and long-term results; however few surgical series have been published on this subject. The purpose of this study is to observe predictors of results in a series of JPAA and to analyse long-term survival of these patients. DESIGN, MATERIALS AND METHODS: Patients' epidemiology and surgical technique used in all cases of JPAA were reviewed and correlated with early results through logistic regression analysis. Early results were compared with those of infrarenal aneurysms (IAA) treated in the same period. Long-term results were obtained through our surveillance protocol (3 months after surgery and yearly thereafter) and calculated by life-table analysis. RESULTS: Fifty JPAA were identified over a total of 1450 aortic aneurysms (3.4%). Surgical approach was: anterior transperitoneal in 38 cases (96%), extended retroperitoneal in one (2%) and thoracoabdominal in one (2%). Suprarenal control was obtained in all cases; at the diaphragm in seven (14%), above both renal arteries in 17 (34%) and above one renal artery in 16 cases (32%). Renal revascularisation was performed in 11 cases (22%; nine unilateral and two bilateral). Overall perioperative mortality was 12%, significantly greater than mortality of IAAs: 50/1400, 3.5% (p < 0.02). Mortality in elective cases was 3/42, 7.1% and in ruptured JPAA 3/8, 37.5%. Independent predictors of early mortality were aneurysm rupture, age > 70 years, and coronary artery disease. Gender, smoking, hypertension, diabetes mellitus, site of proximal aortic clamping, type of aortic reconstruction, visceral revascularisation, and technically difficult cases were not associated with early mortality. Three and five year survivals were 66.8% +/- 9.93 and 40.0% +/- 12.64, respectively. CONCLUSIONS: Surgical treatment of JPAAs is associated with a higher risk of early mortality compared to IAAs and reduced long-term survival. Indications for surgery in JPAAs should consider the risk/benefit ratio rather than focusing on technical aspects which do not seem to significantly influence results.

Adult↗
PubMed1998

Intraoperative assessment of cerebral ischaemia during carotid surgery.

BACKGROUND: This study aimed to evaluate the reliability of somatosensory evoked potentials (SEPs) in identifying clamping ischaemia during carotid surgery under general anaesthesia. METHODS: We reviewed the records of 196 consecutive carotid endarterectomies (CEA) performed under general anaesthesia, out of 1550 patients operated on between 1975 and 1993. SEPs were monitored after contralateral median nerve stimulation at the wrist in all patients. Moreover they received an intravenous bolus of 2500 IU of heparin and the stump pressure was measured. A completion angiography was performed in all patients. An intraluminal shunt was inserted when the amplitude of the N20-P25 SEPs complex decreased by more than 50% of pre-clamping value (pathologic SEPs) or when a preoperative CT-scan showed an ischaemic area in the contralateral hemisphere. In some patients the shunt was not inserted because of technical difficulties or because the pathological SEP complex decrease developed when the suture of the arteriotomy was almost complete. RESULTS AND CONCLUSIONS: As the preclamping amplitude (Ab) of N20-P25 was extremely variable, ranging from 0.9 and 7.5 microV, we adopted the ratio: deltaA=(At-Ab)/Ab (At=amplitude measured during clamping every 2 min at time t). Mean decrease of deltaA measured in the whole group ranged between 15% and 20%, but mean deltaA values in patients with pathological SEPs were around 60%. Even patients with positive CT-scans or with a back-pressure lower than 50 mmHg developed a mean deltaA decrease of about 20%. A pathological SEP was present in 50 patients, but developed in only 12 during the clamping trial. An intraluminal shunt was inserted in 22 cases; the other patients received pharmacological treatment with anaesthetic or vasoactive drugs. Among the patients with pathological SEPs, 3 presented postoperative symptoms related to carotid cross-clamping; only 1 of these was shunted but without SEPs normalisation. No patients with normal SEPs developed a postoperative neurological deficit, giving a reliability of 86.7%, a sensitivity of 100% and a specificity of 86.5%.

Aged↗
PubMed1998

Aorta transplantation in man: clinical and immunological studies.

Aortic transplantation has progressively gained interest over the last few years and it is becoming a first choice indication in the substitution of infected prostheses. The most frequent complication in long-term vascular outcome (wall thickening, aneurysmatic dilation, stenosis), may occur through an immunological mechanism. In this study we investigated nine recipients, aged 48 to 65 years, of aorta segment replacement for anti-HLA antibody production (specificity and Ig class), CD3-CD4-CD8 T cell subpopulation dynamics and aorta wall thickness. Mismatch-specific IgG antibodies to HLA class I and HLA class II antigens were detected 1, 3 and 6 months after transplantation and persisted at a high concentration for at least 1 year. Furthermore, the absolute number of CD3, CD4 and CD8 positive lymphocytes increased progressively after aorta allograft. Tomography scanning showed a progressive thickness of the aorta wall. We can speculate that these anti-HLA antibodies in the recipients have the potential to harm the implant; therefore, aorta allograft should involve the induction of immunological tolerance by appropriate immunosuppressants.

Aged↗
PubMed1996

Prophylaxis of graft infection with rifampicin-bonded Gelseal graft: 2-year follow-up of a prospective clinical trial. Italian Investigators Group.

Between March 1991 and June 1992, 600 patients were treated with mono-, bifemoral or iliofemoral arterial graft revascularization for occlusions and/or aneurysms. The patients were divided into two groups: group A (n = 296) received a Gelseal Vascutek graft immersed for 15 min before implant in a solution containing 1 mg/ml rifampicin; group B (n = 304) received an untreated Gelseal Vascutek graft. Both groups received perioperative antibiotic treatment with cephalosporins. Clinical follow-up was performed at 1, 6, 12 and 24 months after surgery to exclude signs of graft infection. Statistical analysis (X(2)) of pre-, intra- and postoperative risk factors showed both groups to be well matched. Among 600 patients treated, the 2-year follow-up showed 12 cases of graft infection (2.0%): five in group A (1.7%) and seven in group B (2.3%) (P = n.s.). All cases of graft infection originated in the groin and Staphylococcus aureus was isolated in 50% of cases. Statistical analysis (Mann-Whitney U test) showed a significant prevalence of lymphatic complications and immediate redo surgery in patients with graft infection. Of the 12 cases with infection, one was lost to follow-up, three were treated with total graft removal, six with partial graft removal and two with conservative therapy: there were no deaths. In spite of the relatively limited series and follow-up, no statistically significant difference emerged from the clinical use of vascular grafts pretreated with antibiotics.

Aged↗
PubMed1996

Effects of ischemia on the human pancreas.

BACKGROUND & AIMS: Patients undergoing cardiac surgery frequently have pancreatic damage; several factors, including tissue hypoperfusion, have been implicated. The aim of this study is to better understand the effects of decreased blood supply on human pancreas. METHODS: Twenty-one consecutive patients undergoing surgery for thoracic or thoracoabdominal aortic aneurysm were studied. During surgery, the descending thoracic aorta was cross-clamped for a mean of 44 minutes (range, 15-85 minutes). Effects of the resultant pancreatic ischemia were assessed by examining the patients daily for evidence of acute pancreatitis for at least 20 days after surgery and by determining serum concentrations of amylase, pancreatic isoamylase, and lipase before clamping the aorta and at varying intervals after its release (1, 2, and 6 hours during the first day and once daily for the following 6 days). RESULTS: One patient died of acute necrotizing pancreatitis. None of the others had symptoms of pancreatitis postoperatively, but all showed a significant increase in serum pancreatic enzyme concentrations soon after declamping; this peaked about 24 hours later and persisted for all 7 days of the study. A significant relationship was found between the increase in pancreatic enzyme concentrations and the aortic clamping time. CONCLUSIONS: Acinar cell injury is a constant, rapidly appearing consequence of severe pancreatic ischemia, even that of brief duration; acinar cell injury is usually subclinical but may also present as severe acute pancreatitis.

Aged↗
PubMed1996

Extracranial internal carotid artery aneurysms: results of a surgical series with long-term follow-up.

PURPOSE: The purpose of this study was to analyze mode of presentation, surgical treatment, and early and long-term results of a series of extracranial internal carotid artery aneurysms (EICAA). METHODS: A retrospective analysis was performed on all cases treated for EICAA in a single institution from March 1974 to March 1995. Patient follow-up was obtained by a surveillance protocol, with duplex scanning performed 3 months after surgery and yearly thereafter. RESULTS: Twenty-four EICAA in 20 patients were treated over a 21-year period. The cause was fibromuscular dysplasia in 12 cases (50%), nonspecific "atherosclerosis" in nine (37.5%), previous carotid artery surgery in two (8.3%), and trauma in one case (4.1%). Neurologic symptoms were present in a total of nine cases (37.5%) and were hemispheric in seven (29.1%) and nonhemispheric in two (8.3%). Operative techniques were performed with patients receiving general anesthetic and included aneurysm excision with internal carotid artery reanastomosis (8 cases [33.3%]) or reimplantation onto the external carotid artery (1 case [4.1%]); interposition graft (10 cases [41.6%]), 7 veins, 3 polytetrafluoroethylene) or simple aneurysmectomy and closure of the wall defect either with (3 cases [12.5%]) or without (2 cases [8.3%]) a patch. Elective surgery was performed in 22 cases, with a 0% mortality rate and 4.5% stroke rate. Emergency operations were performed in two cases of ruptured aneurysms (one spontaneous and one iatrogenic); one patient (50%) died. Cranial nerve morbidity occurred in five cases (20.8%). Mean follow-up was 96.7 +/- 88.15 months (range 4 to 240 months) and included 2 of 7 (28%) complications in saphenous vein grafts, 1 (4.1%) late transient ischemic attack, and a recurrent aneurysm after 19 years. CONCLUSIONS: Symptoms and potential complications caused by EICAA suggest a broad surgical indication. EICAA can be treated safely because of the good early and long-term results.

Aged↗
PubMed1995

The morphology of elastin in non-specific and inflammatory abdominal aortic aneurysms. A comparative transmission, scanning and immunoelectronmicroscopy study.

The maintenance of the mechanical properties of the vessels results from the correct arrangement of smooth muscle cells and extracellular fibrous proteins (elastin and collagen) in their wall. The morphology of extracellular matrix modifications, particularly of elastin, was investigated in inflammatory (IA) and non specific (NSA) abdominal aortic aneurysms by scanning (SEM), transmission (TEM) and immunoelectron microscopy. Both NSAs and IAs were significantly characterized by extensive extracellular matrix remodelling, including different patterns of elastin degradation. Elastic and collagen fibres distribution appeared to be extensively altered in IAs, while it conformed more to a normal pattern in NSAs. With respect to NSAs, the morphology of elastic fibres in IAs was modified to such an extent that their identification by TEM had a rely on immunocytochemical methods and by SEM on back-scattered electron analysis. The observed ultrastructural changes are indicative of the central role of extracellular matrix modifications in the pathogenesis of IAs and NSAs.

Aortic Aneurysm, Abdominal↗
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↗