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Biomedical subjects

P Fiorani

Publications and source records attributed to P Fiorani.

At least 37 records · Page 2Linked to original sources
PubMed1999

Locoregional versus general anesthesia in carotid surgery: is there an impact on perioperative myocardial ischemia? Results of a prospective monocentric randomized trial.

PURPOSE: The incidence of cardiac morbidity and mortality in patients who undergo carotid surgery ranges from 0.7% to 7.1%, but it still represents almost 50% of all perioperative complications. Because no data are available in literature about the impact of the anesthetic technique on such complications, a prospective randomized monocentric study was undertaken to evaluate the role of local anesthesia (LA) and general anesthesia (GA) on cardiac outcome. METHODS: From November 1995 to February 1998, 107 patients were classified by the cardiologist as cardiac patients (IHD; history of myocardial infarction, previous myocardial revascularization procedures, or myocardial ischemia documented by means of positive electrocardiogram [ECG] stress test results) or noncardiac patients (NIHD; no history of chest pain or negative results for an ECG stress test). The patients were operated on after the randomization for the type of anesthesia (general or local). Continuous computerized 12-lead ECG was performed during the operative procedure and 24 hours postoperatively. The end points of the study were ECG modifications (upsloping or downsloping more than 2 mm) of the sinus tachycardia (ST) segment. RESULTS: Fifty-five patients were classified as IHD, and 52 were classified as NIHD. Twenty-seven of the 55 IHD patients (49%) and 24 of 52 NIHD patients (46%) were operated on under GA. Thirty-six episodes of myocardial ischemia occurred in 22 patients (20.5%). Episodes were slightly more frequent (58%) and longer in the postoperative period (intraoperative, 10 +/- 5 min; postoperative, 60 +/- 45 min; P <. 001). As expected, the prevalence of myocardial ischemia was higher in the group of cardiac patients than in noncardiac group (15 of 55 patients [27%] vs 7 of 52 patients [13%]; P <.02). By comparing the two anesthetic techniques in the overall population, we found a similar prevalence of patients who had myocardial ischemia (GA, 12 of 52 [23%]; LA, 10 of 55 [18%]; P = not significant) and a similar number of ischemic episodes per patient (GA, 1.5 +/- 0.4; LA, 1.8 +/- 0.6; P = not significant). Episodes of myocardial ischemia were similarly distributed in intraoperative and postoperative periods in both groups. It is relevant that under GA, IHD patients represent most of the population who suffered myocardial ischemia (83%). On the contrary, in the group of patients operated on under LA, the prevalence was equally distributed in the two subpopulations. CONCLUSION: The results confirm the different hemodynamic impact of the two anesthetic techniques. Patients who received LA had a rate of myocardial ischemia that was half that of patients who had GA. The small number of cardiac complications do not permit us to make any definitive conclusion on the impact of the two anesthetic techniques on early cardiac morbidity, but the relationship between perioperative ischemic burden and major cardiac events suggests that LA can be used safely, even in high-risk patients undergoing carotid endarterectomy.

Aged↗
PubMed1999

Domain interactions affecting human DNA topoisomerase I catalysis and camptothecin sensitivity.

DNA topoisomerase I (Top1p) relaxes supercoiled DNA by the formation of a covalent intermediate in which the active site tyrosine is transiently bound to the severed DNA strand. The antineoplastic agent camptothecin (Cpt) specifically targets Top1p and several mutations have been isolated that render the enzyme Cpt resistant. The mutated residues, although located in different regions of the enzyme, may constitute part of the Cpt binding site. To begin identifying the structural features of DNA Top1p important for Cpt-induced cytotoxicity, we developed a novel yeast genetic screen to isolate catalytically active, yet Cpt-resistant enzymes from a pool of human top1 mutants. Among the mutations isolated were substitutions of Ser or Val for Gly363, which like the Gly363 to Cys mutation previously reported by us, suppressed the Cpt sensitivity of Top1p. In contrast, each amino-acid substitution differed in its ability to suppress the lethal phenotype and catalytic activity of a human top1 mutant top1T718A that resembles Cpt by stabilizing the covalent intermediate. Biochemical analyses and molecular modeling support a model where interactions between two conserved domains, a central "lip" region containing residue Gly363 and the residues around the active site tyrosine (Tyr723), directly affect the formation of the Cpt-binding site and enzyme catalysis.

Alanine↗
PubMed1999

Percutaneous stenting of the internal carotid artery: the European CAST I Study. Carotid Artery Stent Trial.

PURPOSE: To report the results of a multicenter safety trial of percutaneous carotid stenting performed by vascular surgeons. METHODS: Symptomatic or asymptomatic patients > or = 65 years of age with internal carotid artery (ICA) stenoses > or = 70% and < or = 2-cm long were eligible for enrollment. The procedures were performed in an operating room with the choice of anesthesia and the percutaneous access site at the discretion of the surgeon. Only Palmaz stents were used. RESULTS: From January 1, 1996 to December 31, 1997, 99 patients (74 men, mean age 70 years, range 51 to 94) were enrolled in the study. More than half (57 of 99 patients) were asymptomatic. The direct cervical approach was used predominantly (97%). Three (3%) cases were converted to surgery for inability to access the artery or deploy the stent (technical success 97%). No perioperative death or myocardial infarction was reported. Six (6%) procedural complications included 1 reversible arterial spasm, 2 dissections, 1 cervical hematoma, and 2 residual stenoses. One neurological event reversed within 7 days (1% minor stroke rate) and 4 (4%) transient ischemic attacks resolved within 24 hours. One (1%) asymptomatic early occlusion occurred 2 days postoperatively. No neurological event was observed in the 1- to 24-month follow-up (mean 13 months). Two (2%) patients died of nonprocedurally related causes. No stent compression was seen, but 1 asymptomatic occlusion and 3 asymptomatic, non-flow-limiting restenoses (2 < 40%, 1 at 60%) were found within 1 year (3% restenosis rate on an intention-to-treat basis). Patency was 98% at 1 year. CONCLUSIONS: The results of this trial support the contention that carotid stenting of short ICA lesions can be performed with a low neurological complication rate.

Aged↗
PubMed1998

Clinical usefulness of technetium-99m-HMPAO-labeled leukocyte scan in prosthetic vascular graft infection.

UNLABELLED: The infection of a prosthetic vascular graft (PVGI), although rare, is the most severe complication in reconstructive vascular surgery. The early diagnosis of this complication reduces the death rate from surgery. Aortofemoral graft infections differ clinically from peripheral graft infections in significant ways. The aim of this article is to evaluate separately the reliability of the 99mTc-HMPAO-labeled leukocyte scan or white blood cell count (WBC) in the early detection of both aortofemoral and peripheral graft infections. METHODS: One hundred sixty-two WBCs were performed on 129 consecutive patients with suspected aortofemoral (122 scans) and peripheral (40 scans) graft infection and in a 12-patient control group. Patients with suspected PVGI were categorized into three groups on the basis of their signs and symptoms on readmission: (a) patients with specific signs of graft infection (Group A); (b) patients with nonspecific signs of graft infection (Group B); and (c) patients with anastomotic aneurysms (Group C). Gram's stains of the perigraft exudate and graft cultures were performed and used as the gold standard in patients who underwent surgery. An 18-mo clinical follow-up was done to assess the presence or absence of graft infection in patients who did not have surgery. RESULTS: In patients with suspected aortofemoral graft infections, the overall sensitivity, specificity and accuracy of WBCs (Groups A, B, C) were 100%, 92.5% and 97.5%, respectively, whereas sensitivity, specificity and accuracy calculated in the patients with nonspecific signs of graft infection (Groups B, C) were 100%, 92.3% and 96.9%, respectively. In patients with suspected peripheral graft infections, sensitivity, specificity and accuracy were 100%. CONCLUSION: The white blood cell scan seems a reliable diagnostic method for early diagnosis of PVGI, and it is more useful in aortofemoral graft infections.

Blood Vessel Prosthesis↗
PubMed1998

Outcome after early treatment of popliteal artery aneurysms.

BACKGROUND: Aneurysms of the popliteal artery are rare events with an estimated incidence of 0.1-2.8%. Their clinical importance depends on their propensity to cause thromboembolic complications or to rupture (18 to 31% of cases). This study was designed to assess the advantages of elective treatment of asymptomatic popliteal artery aneurysms so as to avoid the severe clinical manifestations that eventually arise if they remain untreated. METHODS: From 1980 to 1995, in our department we treated 28 popliteal aneurysms in 23 patients (19 elective operations and 6 emergencies). Three of the aneurysms proved amenable to fibrinolytic therapy alone. Follow-up lasted a mean 48 months (range 3 months to 15 years) in 20 patients (23 revascularizations). RESULTS: Global patency was 91.3%. Two thrombosed bypasses were treated by thrombolysis; in one case it did not resolve the ischaemia and the leg was amputated. In one case only, a graft became infected but this responded to conservative therapy with drainage and antibiotics. CONCLUSIONS: These findings suggest that popliteal aneurysms with good distal run-off should be repaired electively. Completely thrombosed aneurysms with coexistent limb-threatening ischaemia should be treated initially by thrombolysis. This will usually restore run-off and in some cases offers a valid alternative to emergency surgery for limb salvage.

Aged↗
PubMed1998

[The role of vena cava filters in the prevention of pulmonary embolism and hemodynamic changes in the venous system of the lower limbs].

BACKGROUND: On the basis of recent investigations, pulmonary embolism represents the third cause of death. If only hospitalized population over 65 years of age is considered, this pathology is quite the first cause of mortality. As deep venous thrombosis of the lower limbs represents the main cause of pulmonary embolism (90%), it should be right to suggest interruption of venous flow at caval level. The aim of this prospective report is to evaluate the efficacy of vena cava filter in pulmonary embolism prevention and the hemodynamic variations it can cause in the venous district of lower limbs. METHODS: 137 definitive caval filters were positionated from 1989 to 1996. Average follow-up was 12.6 months. Patients were controlled at 2-7 days, 1 month and than every 6 months. RESULTS: Filter perviousness was observed with Kaplan and Meyer's curve and it was 94.7%. There was pulmonary embolism in just 2 cases (1.4%). Filter perviousness was not depending on anticoagulant treatment. CONCLUSIONS: In conclusion, this prospective experience underlines that: caval filter is effective in pulmonary embolism prophylaxis; there are not important hemodynamic alterations of inferior vena cava, below filter; anticoagulating treatment does not influence filter perviousness; there are not hemodynamic alterations after slight dislocations of caval filter; finally there is a direct relation between level of deep venous thrombosis and post-phlebitic manifestations.

Hemodynamics↗
PubMed1997

Study of yeast DNA topoisomerase II and its truncation derivatives by transmission electron microscopy.

The 1429-amino acid residue long yeast DNA topoisomerase II and three of its deletion derivatives, a C-terminal truncation containing residues 1-1202, a 92-kDa fragment spanning residues 410-1202, and an A'-fragment spanning residues 660-1202, were examined by transmission electron microscopy. Analysis of rotary-shadowed images of these molecules shows that the full-length enzyme assumes a tripartite structure, in which a large globular core comprising the carboxyl parts of the dimeric enzyme is connected to a pair of smaller spherical masses comprising the ATPase domains of the enzyme. The linkers bridging the large globular structure and each of the smaller spheres are not visible in most of the images but appear to be sufficiently stiff to keep the relative positions of the connected parts. The angle extended by the pair of spherical masses is variable and falls in a range of 50-100 degrees for the majority of the images. On binding of a nonhydrolyzable ATP analog to the enzyme, this angle is significantly reduced as the two spherical masses swing into contact. These observations, together with results from previous biochemical and x-ray crystallographic studies of the enzyme, provide a sketch of the molecular architecture and conformational states of a catalytically active type II DNA topoisomerase.

DNA Topoisomerases, Type II↗
PubMed1997

Bacterial and clinical criteria relating to the outcome of patients undergoing in situ replacement of infected abdominal aortic grafts.

OBJECTIVES: In a retrospective non-randomised study we assessed the outcome after in situ replacement of infected knitted Dacron abdominal aortic grafts in patients without septicaemia or retroperitoneal abscesses. We also assessed whether the specific bacterial infection influenced outcome. MATERIALS AND METHODS: Over the 5 years studied, 18 patients (9 with perigraft infection and 9 with aortoenteric erosion) underwent in situ replacement of aortofemoral grafts. All patients were haemodynamically stable, none required emergency treatment. Preoperative assessment included CT, MRI, leukocyte-labelled scintigraphy, and bacterial cultures whenever possible. Infected grafts were totally excised and replaced in situ with standard PTFE prostheses. Bacterial diagnosis included intraoperative Gram-staining and postoperative graft cultures. None of the patients had retroperitoneal collections or proximal anastomotic dehiscence. All patients had 6 week intravenous antibiotic therapy. RESULTS: One patient died of myocardial infarction, and another of haemorrhagic shock from proximal anastomotic dehiscence, accounting for a graft-related mortality of 6%. Dehiscence resulted from a polymicrobial infection. Mean 37 month surveillance showed no amputations and no graft-related infections. CONCLUSIONS: In clinically and bacteriologically selected patients, total in situ replacement of infected abdominal aortic grafts offers an excellent outcome.

Adult↗
PubMed1997

General anaesthesia versus cervical block and perioperative complications in carotid artery surgery.

PURPOSE: To compare the influence of anaesthetic technique on perioperative complications in patients undergoing carotid endarterectomy. MATERIAL AND METHODS: In a retrospective study of 1020 consecutive patients who underwent carotid artery surgery over 10 years, perioperative neurologic and cardiologic complications and the use of an internal carotid artery shunt were compared in 337 patients (33%) treated under general anaesthesia and 683 (67%) under cervical block. The two groups had similar characteristics. The most frequent surgical indication was symptomatic carotid artery disease (91.5%). The remaining patients had asymptomatic severe internal carotid lesions (> 70%). RESULTS: The overall perioperative stroke rate was 1.9%, the death-stroke rate 0.7% and the cardiac complication rate 0.8%. The perioperative stroke rate was higher in the general anaesthesia group than in the cervical block group (3.2% vs 1.3%, p = 0.01). Cardiac complication rates were similar in the two groups. A carotid artery shunt was used in 75 patients (22%) receiving general anaesthesia and in 92 patients (13%) receiving cervical block (p = 0.0004). The causes of stroke in the cervical block group were intraoperative embolism (4 cases, 26%), perioperative thromboembolism (7 cases, 58%) and clamping ischaemia (1 case, 16%). Mechanisms causing stroke in the general anaesthesia group remained unidentified or uncertain. CONCLUSIONS: Cervical block anaesthesia yields better perioperative results than general anaesthesia probably because it allows more reliable cerebral monitoring, reducing or even eliminating perioperative strokes related to clamping ischaemia. It facilitates detection of the mechanism underlying intraoperative stroke allowing surgical techniques and intraoperative management to be modified accordingly. Cervical block anaesthesia significantly reduces the need for internal carotid artery shunting.

Adult↗