Early Carotid Endarterectomy after Ischemic Stroke: The Results of a Prospective Multicenter Italian Study

OBJECTIVES

To evaluate safety of early carotid endarterectomy (CEA) in patients with acute brain ischemia presenting to the emergency department stroke units (EDSU).

METHODS

The neurologists, neuroradiologists and vascular surgeons on duty in emergency departments enrolled 96 patients who underwent very early CEA according to a predefined protocol within two years. The protocol included evaluation of neurological status by National Institute of Health Stroke Scale (NIHSS), neuroimaging assessment, ultrasound of the carotid arteries and Transcranial Doppler. Patients with NIHSS>22 or whose neuroimaging showed brain infarct >2/3 of the middle cerebral artery territory were excluded. All eligible patients underwent CEA as soon as possible. Primary end points of the study were mortality, neurological morbidity by NIHSS and postoperative hemorrhagic conversion on neuroimaging. Statistical analysis was performed by univariate analysis.

RESULTS

The mean time elapsing between the onset of stroke and endarterectomy was 1.5 days (+/-2 days). The overall 30-day morbidity mortality rate was 7.3% (7/96). No neurological mortality occurred. On hospital discharge, three patients (3%) experienced worsening of the neurological deficit (NIHSS score 1 to 2, 1 to 3 and 9 to 10 respectively). Postoperative CT demonstrated there were no new cerebral infarcts nor hemorrhagic transformation. At hospital discharge 9/96 patients (9%) had no improvement in NHISS scores, 37 were asymptomatic and 45 showed a median decrease of 4.5 NIHSS points (range 1-18). By univariate analysis none of the considered variables influenced the clinical outcome.

CONCLUSION

Our protocol selected patients who can safely undergo very early (<1.5 days) surgery after acute brain ischemia. Large randomized multicenter prospective trials are warranted to compare very early CEA versus best medical therapy.

Dysregulated apoptosis in primary varicose veins

OBJECTIVE

Programmed cell death plays a critical role in various physiological processes. To investigate its possible pathogenic role in primary varicose veins we studied histological changes in surgical specimens from human varicose veins. In varicose and healthy veins, we also determined the number of cells in apoptosis, and investigated mediators regulating the intrinsic apoptotic mitochondrial pathway (Bax and caspase 9).

METHODS

A total 23 varicose veins were obtained from 18 patients undergoing lower-extremity varicose vein surgery for primary varicose disorders. We used nine healthy veins obtained from nine patients undergoing distal arterial bypass grafting surgery as controls. The venous segment analysed was the distal part of the greater saphenous vein. Specimens for histological examination were stained with hematoxylin and eosin, trichromic and Victoria blue. Cell apoptoses and mediators of the mitochondrial pathway were detected in the media by immunohistochemistry using antibodies to peroxidase in situ apoptosis, Bax and caspase 9. Results were expressed as indexes for the three antibodies tested. The Mann-Whitney test was used to compare the results obtained in the two groups.

RESULTS

Varicose vein specimens exhibited a more disorganised architecture than healthy veins and showed an increased number of collagen fibres and a decrease in the density and size of elastic fibres. All anti-apoptotic antibodies tested detected significantly fewer immunoreactive cells in tissue sections from the media of varicose veins than of healthy veins (peroxidase in situ, varicose veins (VV) median 2.4% (inter-quartile range 1.6-3.9) versus control (C) 14% (IQR 8.8-19); Bax, VV 1.4% (IQR 0.36-2.4) versus C 11% (IQR 7.6-15); and caspase 9, VV 1.7% (IQR 0.06-3.4) versus C 10% (IQR 9.1-12), P=0.0001 (Mann-Whitney test).

CONCLUSION

Apoptosis is down regulated in the medial layer of varicose veins. This dysregulation of the cellular mechanism that maintains normal tissue integrity is mediated through the intrinsic apoptotic pathway and may be among the causes of primary varicose veins.

What is the best management for abdominal aortic aneurysm in patients at high surgical risk? A single-center review

AIM

To determine the best treatment for high-risk patients with abdominal aortic aneurysms (AAA).

METHODS

We reviewed a prospective database of all patients who underwent conventional (OPEN) or endovascular aneurysm repair (EVAR) between January 1998 and December 2002. Patients were preoperatively classified according to the American Society of Anesthesiology (ASA). Comorbidities and medical risk factors were categorized according to the Ad Hoc Committee on Reporting Standards. Perioperative mortality and morbidity rates were analyzed according to the type of surgical procedure (OPEN vs EVAR) and ASA class. Patients in ASA classes I and II were excluded. Continuous data were expressed as mean +/- standard deviation. All data were calculated using the cumulated actuarial method of event outcome probability. Kaplan-Meier curves were constructed and the log-rank statistic and chi squared test were used for comparative data. P values less than 0.05 were considered to indicate statistical significance.

RESULTS

Of the total 375 patients who underwent AAA repair, 168 (45%) belonged in ASA classes III and IV (85 submitted OPEN and 83 EVAR to repair). Among general risk factors only coronary artery disease differed significantly between the 4 groups (P = 0.04). The Bonferroni correction identified a statistically significant difference between ASA classes III and IV for the OPEN technique and for EVAR (P = 0.007 and P = 0.012). Neither 30-day morbidity or mortality differed significantly according to ASA class and surgical technique. The median follow-up was 19 months (range 5-60 months). The overall survival was 78% at 60 months. Survival rates during follow-up differed significantly in the 2 risk classes (ASA III 5/123, 4% vs ASA IV 9/38, 24%), (P = 0.0001). The deaths in the ASA class 4 patients (12/14; 86%) were caused by preexisting medical comorbidities (in 9 patients cardiovascular, in 1 cancer and in 2 cirrhosis).

CONCLUSIONS

Except patients with small aneurysms (< 6 cm), in whom the risk of death at 1-year due to comorbidities exceeds the risk of a ruptured aneurysm, all patients at high surgical risk (ASA class IV) benefit from AAA repair. Patients with small aneurysms must undergo strict surveillance to assess growth and aneurysmal wall changes to prevent unexpected rupture.

[Atheroembolic syndrome due to isolated infrarenal abdominal aorta stenosis and endovascular treatment: case report and review of literature]

One of the most common source of lower extremity atheroembolization is the aorta and particularly the infrarenal segment. Complex atherosclerotic plaque can lead the patient to gangrene and major amputation. When the origin of embolization is a focal lesion, endoluminal methods could be an alternative to surgical treatment. Although the experience with aortic stent is limited, the results obtained so far seem to be encouraging. The case of a mid-age heavy smoker woman with a history of the abrupt onset of painfull cyanotic toes in the left foot and subsequent complete gangrene of the first digit in the same foot is herein reported. Angiography and CT scan revealed an high-grade calcified aortic infrarenal plaque. Because of the discrete characteristic of the lesion, an endovascular approach with a Palmaz stent was elected. The stenosis was successfully treated: the patient experienced the complete resolution of the toe painfull cyanosis within 3 months, the stent remained patent through a 24 months follow-up and no subsequent embolic episodes were observed.

Interposition Vein Cuff and Intimal Hyperplasia: An Experimental Study

OBJECTIVE

There is some evidence to suggest that prosthetic distal bypass graft patency can be improved, and the risk of intimal hyperplasia diminished, by interposing a distal vein cuff. We studied intimal remodeling in an end-to-side distal prosthetic anastomosis constructed with and without a vein cuff.

METHODS

Twenty-four prosthetic bypasses were constructed with (N=12) or without (N=12) a distal vein cuff in 12 pigs. At 10 weeks, the 20 anastomoses and adjacent arteries from the surviving 10 pigs were studied by histology, immunohistochemistry and morphometry.

RESULTS

Intimal hyperplasia was significantly less on all zones of the arterial floor and all suture zone of arteries anastomosed with a vein cuff than within arteries anastomosed without a vein cuff (0.11 versus 0.34; p=0.001 and 0.35 versus 1.19; p=0.0001, respectively). Intimal hyperplasia was also more prominent within the vein cuff than within the recipient artery, with or without a vein cuff (1.35 versus 0.38; p=0.0001).

CONCLUSION

An interposition vein cuff at the distal anastomosis between a prosthesis and an artery alters the distribution of intimal hyperplasia. By acting as an expansion chamber where intimal hyperplasia can develop harmlessly, the vein cuff may protect the arterial anastomosis from stenosis.

Aneurysm of the pancreaticoduodenal arteries with a celiac trunk lesion: current management

OBJECTIVE

We report a ruptured aneurysm of the pancreaticoduodenal arteries without acute or chronic pancreatitis but associated with a median arcuate ligament division that compressed the celiac trunk, an exceptional event, thus far described in only 11 patients. We also conducted a targeted review to seek information about clinical presentation, to hasten diagnosis and assist in therapeutic management.

METHODS

A 54-year-old man with retroperitoneal hemorrhage associated with an arcuate ligament division, documented on computed tomographic scans, underwent diagnostic arteriography and embolization to treat the bleeding aneurysm. In a second elective operation the causative arcuate ligament was sectioned to decompress the celiac artery, to prevent aneurysm recurrence.

RESULTS

Embolization stopped the aneurysmal bleeding, and arteriograms showed that surgical sectioning resolved the celiac trunk stenosis. At 1-year follow-up the patient had no signs of complications or recurrence of disease.

CONCLUSION

Ruptured aneurysm of the pancreaticoduodenal arteries associated with stenosis of the celiac trunk is a surgical emergency. Although a literature review disclosed no significant difference between outcomes after open surgery and radiologic arterial embolization, our experience in this case suggests immediate embolization during arteriography as the most effective treatment. Later, to prevent recurrence, the arcuate ligament should be surgically sectioned and the celiac artery stenosis treated.

Patency and Limb Salvage after Distal Prosthetic Bypass Associated with Vein Cuff and Arteriovenous Fistula

OBJECTIVE

To assess the usefulness of vein cuff with or without arteriovenous fistula interposition as adjuvant techniques for improving patency and limb salvage in patients undergoing femorodistal bypass surgery using prosthetic grafts.

METHOD

We undertook a retrospective study of 65 consecutive patients treated over a 5-year period with 67 prosthetic femorodistal bypasses with vein cuff, in whom an arteriovenous fistula was constructed at the distal anastomosis in 35. Patients were followed for a median time period of 23 months.

RESULTS

Primary patency rates were 68, 53 and 44% at 1, 2 and 3 years, respectively. The corresponding figures for secondary patency, limb survival and patients' survival were 73, 64 and 58% for 1 year, 78, 76 and 73% for 2 years and 72, 66 and 63% for 3 years. None of the criteria analyzed influenced patency or limb salvage on prosthetic bypasses using adjuvant techniques. No statistical differences were found between patency and limb salvage rates in patients for whom the vein cuff was constructed with or without an arteriovenous fistula. But patients who managed with a supplementary arteriovenous fistula had significantly fewer distal residual arteries in the limb (p=0.001).

CONCLUSION

Although results in patients treated with adjunctive techniques differed little from those in patients treated with direct prosthetic bypasses procedures, those who eventually had an adjunctive procedure had inferior runoff. This indicates that an arteriovenous fistula might be a valuable supplement in patients with poor runoff who have distal revascularisation using a prosthetic graft.

Popliteal Artery Entrapment Associated with Cannabis Arteritis

OBJECTIVE

To report popliteal artery entrapment in a patient with distal necrosis and cannabis-related arteritis, two rare or exceptional disorders never described in association. To conduct a targeted review and especially to seek information on the clinical presentation with characteristics specific to each disorder so as to hasten the diagnosis and choose appropriate management.

MATERIAL AND METHODS

A 19-year-old man who presented with plantar claudication associated with necrosis in a toe underwent diagnostic arteriography and surgery for popliteal artery entrapment type III.

RESULTS

Surgical clearance resolved the popliteal artery entrapment but left the clinical symptoms unchanged. Closer questioning disclosed a history of cannabis consumption and intravenous vasodilatory therapy was started. After the 21-day course of vasodilator agents the pain disappeared and the toe necrosis regressed. The patient stopped taking cannabis and had no signs of recurrence.

CONCLUSION

Whereas a popliteal artery entrapment, albeit a rare event, is well described and responds to standardized treatment, popliteal artery entrapment associated with cannabis-induced arteritis is an exceptional event that could confuse management. Because young people-the age group mainly at risk for popliteal artery entrapment-increasingly use cannabis, cannabis arteritis could become a more frequent event associated with other arterial disorders that may confuse the diagnosis and complicate management. Our experience in a young patient suggests that coexisting popliteal artery entrapment and distal necrosis in a young patient should raise a strong suspicion of an associated vascular disorder possibly related to cannabis consumption. Intravenous vasodilatation treatment is successful provided that cannabis use is discontinued.

Emergency and early carotid endarterectomy in patients with acute ischemic stroke selected with a predefined protocol. A prospective pilot study

AIM

The appropriateness of early carotid endarterectomy (CEA) in patients with acute ischemic stroke is still unsettled. The aim of this study was to verify the safety and feasibility of early CEA in a consecutive series of patients with acute ischemic stroke observed in an emergency Department Stroke Unit.

METHODS

During a 24-month study, out of 756 patients with acute ischemic stroke 33 (4.4%) were scheduled for early CEA. Endarterectomy procedures were distinguished according to the time between the onset of stroke and operation as emergency (within 8 hours), early CEA (1-18 days). Patients with impaired consciousness or an infarct larger than 2.5 cm on computed tomographic (CT) or magnetic resonance (MR) scans or both were excluded from surgery. All patients underwent spiral CT, echo-color-Doppler (ECD) sonography, transcranial Doppler (TCD) sonography and, when necessary, MR angiography within 6 hours of admission. No patient underwent conventional angiography. Most patients were operated on under cervical block (CB) anesthesia; general anesthesia (GA) was used only for those with an unstable neurological deficit. Selective shunting was used on the basis of intra-operative transcranial Doppler in patients under GA and the onset or worsening of neurological deficit under CB anesthesia.

RESULTS

Of the 6 patients operated on within a median 6 hours after the onset of stroke, 1 (16.5%) had a fatal hemorrhagic transformation of the infarct, while the remaining 5 (83.5%) stopped fluctuating or progressing and had a favourable neurological outcome. Of the 16 patients operated on within a median 36 hours and of the 11 patients operated on within 7 days, none deteriorated after operation.

CONCLUSION

Emergency CEA is feasible for acute ischaemic stroke provided that strict selection criteria are applied and the door-to-surgery interval is kept short (within 8 hours). Early CEA for secondary prevention is feasible and safe, confirming that a delayed operation is in most cases unwarranted. Large randomized trials are warranted before implementing emergent and early CEA in routine clinical practice.

[Role of aortofemoral bypass in the management of unilateral iliac occlusive disease. A follow-up study of 95 patients over a 25-year period]

BACKGROUND

To evaluate the results in a series of patients submitted to aortofemoral bypass due to an unilateral iliac occlusion.

METHODS

Retrospective follow-up study. A total of 95 patients underwent, between 1975 and 2000, aortofemoral bypass because of unilateral iliac occlusion. Most of them (71 patients) were claudicants, Fontaine stage II b, while 12 complained rest pain and 12 suffered ischemic ulcers. Mean follow-up was 128 months (min 2.5 - max 292).

RESULTS

Immediate success was obtained in 88 cases (92.6%), 7 patients were submitted to early redo with restored patency in 6 cases. One month global patency was gained in 98.9% (94 cases). The mean Ankle-brachial index (ABI) improvement was 0.35. At a mean follow-up of 128 months the cumulative patency was 90.8%. During the follow-up, 15 graft occlusions were observed, followed by 9 successful reoperations achieving a 5-year secondary patency of 92.1%. The contralateral iliac artery evolved toward an occlusion in 10 patients (10.5%) during a long time observation (104 months average).

CONCLUSIONS

The unilateral aortofemoral bypass confirmed an excellent long term outcome regarding effectiveness and graft related complications. The low contralateral occlusion rate, in our series, does not justify a more aggressive approach as first surgical option.

The role of preoperative Tc-99m HMPAO-labeled leukocyte total-body scans in aortic prosthetic reconstruction

PURPOSE

This study was performed to evaluate the utility of Tc-99m HMPAO-labeled leukocyte total-body scans (TBLS) for detecting remote septic foci before operation in patients undergoing aortofemoral vascular surgery.

MATERIALS AND METHODS

Fifty-eight patients were screened before operation for inflammatory or infective disease, and a clinical score was assigned to each patient. Each patient had TBLSs. The relation between the clinical score and the TBLS result was determined. Patients with positive results of the TBLSs were examined, and the causes of these findings were treated before surgery.

RESULTS

Ten of the 58 (17%) patients had a positive result of TBLSs. Of 31 patients with a clinical score of zero, 3 had positive findings of TBLS. No TBLS was positive in the 13 patients with a clinical score of 1. TBLS findings were positive in 7 of 14 of the combined patients with clinical scores of 2, 3, or 4. None of the patients showed signs of prosthetic vascular graft infection during the postoperative follow-up period.

CONCLUSIONS

In conclusion, TBLSs can be used before aortofemoral vascular surgery, but only in patients with high clinical scores for inflammatory or infective disease to identify relevant infective foci that could cause vascular graft infection.

Somatosensory Evoked Potentials versus Locoregional Anaesthesia in the Monitoring of Cerebral Function During Carotid Artery Surgery: Preliminary Results of a Prospective Study

OBJECTIVE

to relate changes in somatosensory-evoked potentials (SEPs) with onset of neurological deficits in patients having carotid endarterectomy (CEA) under locoregional anaesthesia.

METHODS

a prospective study of 50 consecutive patients.

RESULTS

SEPs yielded an accuracy of 98%, specificity 100%, and sensitivity 89%. In all concordant cases the onset of a neurological deficit in awake patients corresponded to a 30--40% reduction in amplitude of N20-P25 waveforms. After shunting, the N20-P25 took 2--3 min to return to normal.

CONCLUSIONS

SEPs are associated with a 2% false negative rate. Their threshold for detecting cerebral ischaemia is lower than the currently reported value for patients under general anaesthesia. The time needed for evoked potentials (2--3 min) to return to normal after shunting limits their usefulness in verifying effective shunting.

Mechanisms of DNA topoisomerase I-induced cell killing in the yeast Saccharomyces cerevisiae

DNA topoisomerase I (Top1) catalyzes the relaxation of supercoiled DNA by a mechanism of transient DNA strand cleavage characterized by the formation of a phosphotyrosyl bond between the DNA end and active site tyrosine. Camptothecin reversibly stabilizes the covalent enzyme-DNA intermediate by inhibiting DNA religation. During S-phase, collisions with advancing replication forks convert these complexes into potentially lethal lesions. To define the DNA damage induced by alterations in Top1p catalysis and the cellular processes that mediate the repair of such lesions, the yeast Saccharomyces cerevisiae was used. Substitution of conserved residues N-terminal to the active site tyrosine (Tyr-727) produced alterations in the camptothecin sensitivity or catalytic cycle of DNA Top1. For example, substituting Ala for Thr-722 in Top1T722A increased the stability of the covalent enzyme DNA intermediate. As with camptothecin, Top1T722A-induced cytotoxicity was ascribed to a reduction in DNA religation. By contrast, enhanced covalent complex formation by Top1N726H resulted from a relative increase in the rate of DNA cleavage. Conditional yeast mutants were also selected that exhibit temperature-sensitive growth only in the presence of the self-poisoning Top1T722A enzyme. Subsequent analyses of these tah mutants identified 9 genes whose function suppresses the cytotoxic action of camptothecin and Top1T722A. These include genes encoding essential DNA replication proteins (CDC45 and DPB11) and proteins involved in SUMO- or ubiquitination (UBC9 and DOA4).

Inflammatory aneurysms of the abdominal aorta involving the ureters: is combined treatment really necessary?

PURPOSE

Peri-aneurysmal fibrosis complicating inflammatory aneurysm of the abdominal aorta may involve the ureters, causing urological complications. We assessed patient anatomical and clinical outcomes after conservative ureteral management.

MATERIALS AND METHODS

From the operative records of 1,271 consecutive patients who underwent surgical repair of abdominal aortic aneurysms from 1980 to 1999 we identified 77 (6%) who had inflammatory aneurysms, which were complicated in 19 (24.6%) by dense peri-aneurysmal and ureteral fibrosis. Of these 19 patients 15 (78.9%) had coexisting monolateral hydronephrosis, 3 (15.7%) had bilateral hydronephrosis and 1 (5.2%) had renal atrophy. In 14 cases (73.6%) the fibrotic reaction severely impaired renal function. Only 1 patient underwent an emergency operation, while the others underwent elective repair. Only 2 patients (10.5%) underwent a specific urological procedure, including bilateral nephrostomy in 1 and ureterolysis plus ureterolithotomy in 1. Most ureteral complications were treated conservatively by aneurysmectomy only.

RESULTS

Immediate postoperative mortality was 7% (1 of 14 cases). Median followup was 48 months. In 1 of the 13 cases (7.7%) a ureteral stent was placed during followup. After aneurysmectomy in 9 of the 12 patients (75%) with renal dysfunction periaortic fibrosis disappeared or decreased as well as associated hydronephrosis. In 11 of the remaining 12 patients (91%) of the 14 with renal failure preoperatively kidney function returned to normal or improved. In the 2 patients who underwent a specific urological procedure renal function improved but did not return to normal.

CONCLUSIONS

Inflammatory abdominal aortic aneurysms involving the ureters and compressing the urinary structures respond well to aneurysmal resection only without a urological procedure.

The haemodynamic effect of internal carotid artery stenosis on cerebral perfusion during aortic surgery

OBJECTIVES

to determine the impact of the extracranial internal carotid stenosis on cerebral perfusion during aortoiliac surgery.

DESIGN

prospective study.

MATERIAL AND METHODS

of 432 consecutive patients undergoing aortoiliac reconstruction, 16/86 (18%) with >70% internal carotid artery stenosis, underwent inverted surgical timing (aortic reconstruction first and carotid endarterectomy second). Preoperative Transcranial Doppler (TCD) with and without acetazolamide was used to evaluate cerebrovascular reserve capacity (CRC). Intraoperatively, middle cerebral artery flow velocity (mean MCAv) and systemic blood pressure (SBP) were recorded.

RESULTS

preoperatively, all 16 patients had good CRC (increase in mean MCAv: 66% right and 72% left). Intraoperatively, the mean MCAv (from 49+/-13 to 45+/-14 cm/s p=0.0249) and SBP decreased (from 127+/-25 to 113+/-22 mmHg p=0.0016). In patients with unilateral carotid disease, declamping had no effect on left mean MCAv despite a significant decrease of SBP (129+/-44 to 113+/-21 mmHg p=0.0211). In those with bilateral disease, declamping decreased both mean MCAv: from (48+/-12 to 39+/-10 cm/s p=0.011) and SBP (123+/-26 to 111+/-25 mmHg p=0.0479). No perioperative neurological deficit occurred.

CONCLUSIONS

if CRC is normal or still effective, aortoiliac reconstruction does not impair cerebral perfusion.

Non-atherosclerotic saccular aneurysmal degeneration of a saphenous-vein graft inserted for repair of a popliteal aneurysm

The Authors describe a case of a saccular aneurysm formation in a femoropopliteal autologous saphenous vein graft, inserted 12 years before. The patient was initially treated for a popliteal aneurysm. The graft revealed no microscopic signs of atherosclerosis. In spite of the widespread use of the autologous saphenous vein as arterial substitute, this complication is extremely rare.

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.

CDC45 and DPB11 are required for processive DNA replication and resistance to DNA topoisomerase I-mediated DNA damage

The antitumor agent camptothecin targets DNA topoisomerase I by reversibly stabilizing a covalent enzyme-DNA intermediate. The subsequent collision of DNA replication forks with these drug-enzyme-DNA complexes produces the cytotoxic DNA lesions that signal cell cycle arrest and ultimately lead to cell death. Despite intense investigation, the character of the lesions produced and the repair processes that resolve the damage remain poorly defined. A yeast genetic screen was implemented to isolate conditional mutants with enhanced sensitivity to DNA topoisomerase I-mediated DNA damage. Cells exhibiting temperature-sensitive growth in the presence of the DNA topoisomerase I mutant, Top1T722Ap, were selected. Substitution of Ala for Thr722 increases the stability of the covalent Top1T722Ap-DNA intermediate, mimicking the cytotoxic action of camptothecin. Two mutants isolated, cdc45-10 and dpb11-10, exhibited specific defects in DNA replication and a synthetic lethal phenotype in the absence of DNA damaging agents. The accumulation of Okazaki fragments under nonpermissive conditions suggests a common function in promoting processive DNA replication through polymerase switching. These results provide a mechanistic basis for understanding the cellular processes involved in the resolution of DNA damage induced by camptothecin and DNA topoisomerase I.

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.

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.

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

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.

[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.

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.

[Intra and postoperative control in carotid surgery]

After fourty years of practice in carotid surgery the rate of neurologic complications related to technical defects seems not to be reduced and still is responsible of 30-40% of all perioperative strokes. Intraoperative quality control seem at present, of outmost importance to further reduce the impact of technical defects on perioperative neurological complications. Angiography, Duplex Scanning and more recently angioscopy have been utilized as intraoperative assessments. All of them demonstrated imperfections of arterial reconstruction potentially at risk for early and late patency failure and indicated immediate intraoperative correction. In some report this behaviour determined a relevant reduction both on perioperative results and lesser incidence of early restenosis. Concerning postoperative control of carotid endarterectomy early restenosis represent the most important and more common failure after carotid endarterectomy. In spite of the efforts to clear the causes of this phenomenon, none of the numerous papers published in literature has defined a specific cause determining restenosis. Nevertheless, at present, this hyperplastic response of the arterial wall to trauma after operation is generally considered benign because rarely is responsible for new neurological symptoms or early internal carotid artery occlusion. This unanimous conviction has been achieved after years of instrumental and clinical postoperative follow-up performed all over the world. At the same time and probably for the above mentioned reasons, recently, has begun a new discussion about the usefulness and cost-effectiveness of prolonged Duplex scanning postoperative surveillance of the endarterectomized carotid arteries. After a meticolous review of our experience as the review of many reports of literature we, in agreement with others, are convinced that the patients operated of carotid endarterectomy, need, in most cases, a short even aggressive period of careful follow up (generally the first six months). If during this period no irregularities or new stenosis is detected at the site of the endarterectomy, we believe that it is justified the patients to be withdrawn from a prolonged instrumental follow-up, permitting laboratory working time to be redirected towards the diagnosis of new vascular diseases.

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.

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.

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.

[Diagnostic methods and therapeutic options in vasculogenic impotence]

Until a few years ago, the main cause of men's genital impotence was reputed to be psychogenic. On the other hand, the development of diagnostic techniques has been in aid in isolating the most frequent cause of impotence among the organic forms, and in particular those of vascular origin. The authors herein examine the diagnostic methods of vasculogenic impotence and evaluate the therapeutic options in relation to the various causes identified.

Intraoperative transcranial Doppler sonography monitoring during carotid surgery under locoregional anaesthesia

OBJECTIVES

Studies comparing transcranial Doppler ultrasonography (TCD) with other intraoperative monitoring techniques for detecting clamping ischaemia during carotid endarterectomy under general anaesthesia suggest that a reduction of > two-thirds in the mean middle cerebral artery velocity (mMCAv) or a reduction of > 0.4 in the preclamping mMCAv: clamping mMCAv ratio warrants cerebral protection. Our aim was to study the relationship between mMCAvs and clamping ischaemia during carotid endarterectomy in awake patients.

MATERIALS AND METHODS

In a consecutive series of 57 patients undergoing carotid endarterectomy under locoregional anaesthesia 51 were monitored by intraoperative TCD, continuous EEG, and neurologic awake testing.

RESULTS

Five of the 51 (9.8%) patients had transient clamping ischaemia, which carotid shunting reversed. TCD showed that these five patients had significant lower mean mMCAvs than the other 46 patients, who had no deficits (1.8 +/- 1.1 cm/s vs. 26.2 +/- 8.5, p = 0.0003). Current TCD criteria indicated that four other patients (7.8%) should have been shunted. All four had significantly higher clamping mMCAvs than the five shunted patients (11.5 +/- 1.9 vs. 1.8 +/- 1.1, p = 0.0012).

CONCLUSIONS

Intraoperative TCD detected cerebral ischaemia and yielded no false-negative. An mMCAv of 10 cm/s or less may indicate the risk of clamping ischaemia better than the higher threshold currently proposed. This would avoid unnecessary shunting due to false-positives.

Preparation and biodistribution of 99m technetium labelled oxidized LDL in man

Radiolabelled autologous low density lipoprotein (LDL) has previously been used to study in vivo distribution and metabolism of native-LDL. Non-invasive imaging of atherosclerotic lesions using 99mTc-LDL was shown to be feasible in animal models and patients but the clinical utility remains to be assessed. Since recent reports suggest that oxidized LDL may play a major role in the pathogenesis of atherosclerosis, we developed a technique to oxidize autologous LDL and compared the biodistribution of oxidized-LDL with that of native-LDL in man. In addition, we evaluated the uptake in vivo of oxidized- and native-LDL by atherosclerotic plaques. LDL, obtained from human plasma was treated with various combinations of copper ions and H2O2 to induce oxidative modification by increasing the content of lipid peroxidation products and electrophoretic mobility. When LDL (0.3 mg/ml) was incubated with 100 microM Cu2+ and 500 microM H2O2 oxidation occurred rapidly within 1 h, and was labelled with 99mTc efficiently as native LDL. In vivo distribution studies revealed a faster plasma clearance of oxidized-LDL compared to native-LDL, and a higher uptake by the reticuloendothelial system. Tomographic scintigraphy of the neck in patients suffering from transient ischemic attacks, revealed accumulation of radiolabelled LDL preparations in the carotid artery affected by atherosclerotic lesions. We developed a technique to rapidly oxidize LDL using copper and H2O2. Biodistribution data demonstrate that oxidized-LDL is rapidly cleared from circulation, is taken up mostly by organs rich in macrophages, and can be detected at the level of carotid plaques.

[Treatment of prostheto-digestive fistulas using in situ prosthetic bypass]

Secondary aorto-enteric fistula is one of the most serious complications of abdominal aortic reconstruction. Conventional management includes removal of all infected prosthetic graft, oversewing of aortic stump and restoration of lower limbs blood flow by extraanatomic bypass grafting, reporting high rates of mortality, limb loss, and even infection of the extraanatomic grafts. Dissatisfied by these results, frequently, due to aortic stump blowout or extraanatomic by-pass reinfection, some authors attempted a more conservative approach with au in situ replacement by a new synthetic graft. The aim of this paper was to verify the role of in situ graft replacement. From December 1989, 8 patients with secondary aorto-enteric fistula underwent in situ PTFE graft replacement. One patient (12.5%) died perioperatively for acute myocardial infarction. No limb loss occurred. One patient died after 44 months from pulmonary neoplasia without signs of graft infection. The others are doing well at 34 months follow-up. The authors suggest that, in selected patients, in situ prosthetic graft replacement provides better early and late results than extranatomic bypass.

For how long should carotid endarterectomy surveillance be continued?

Early restenosis represent the most important and more common failure after carotid endarterectomy. For this reason, after its first description made in 1976 by Stoney and String, it raised general interest among vascular surgeons. In spite of the efforts to clear the causes of this phenomenon, none of the numerous papers published in the literature has defined a specific cause determining restenosis. Nevertheless, at present, this hyperplastic response of the arterial wall to trauma after operation is generally considered benign because it is rarely responsible for new neurological symptoms or early internal carotid artery occlusion. This unanimous conviction has been achieved after years of instrumental and clinical postoperative follow-up performed all over the world. At the same time and probably for these reasons, recently, a new discussion has begun about the usefulness and cost-effectiveness of prolonged Duplex scanning postoperative surveillance of the endarterectomized carotid arteries. This new question raised our curiosity in verifying the validity of this new approach, so we reviewed accurately our laboratory follow-up registry and the data regarding onset, evolution and clinical outcome of early restenosis. These data associated with a meticulous review of the experience of other authors convinced us that the patients operated on, need, in most cases, a short even aggressive period of careful follow-up (generally the first six months).(ABSTRACT TRUNCATED AT 250 WORDS)

Camptothecin resistance from a single mutation changing glycine 363 of human DNA topoisomerase I to cysteine

A full-length human DNA topoisomerase I complementary DNA clone was mutagenized in vitro and the mutagenized DNA was used to replace wild-type human TOP1 complementary DNA in YCpGAL1-hTOP1, a plasmid constructed for the expression of the human enzyme in yeast. A yeast strain devoid of yeast DNA topoisomerase I and permeable to the anticancer drug camptothecin was transformed with the plasmid pool. Assays of DNA topoisomerase I in lysates of camptothecin-resistant transformants identified one with nearly the same level of the enzyme as transformants of unmutagenized YCpGAL1-hTOP1, and a single mutation changing Gly363 to a cysteine was found in this mutant. The G363C mutant enzyme was overexpressed in yeast and partially purified. It differed significantly from wild-type human DNA topoisomerase I similarly expressed and purified: camptothecin-stimulated cleavage of DNA was observed with the wild-type but not the G363C enzyme, and the DNA relaxation activity of the mutant enzyme, unlike that of the wild-type enzyme, was not significantly stimulated by Mg(II). The positions of the G363C and other previously reported camptothecin resistance mutations in eukaryotic DNA topoisomerase I were discussed in terms of a model in which the active site is an interdomainal cleft.

Aorto-femoral graft infections: a clinical and microbiological analysis

A 5-year experience of 19 aortic graft infections is reviewed. Of these, 13 (68%) had a late onset (more than 4 months after graft implantation) and usually presented with anastomotic pseudo-aneurysm or thrombosis. The remaining six infections (32%) had an early onset and presented more often with surgical wound infection. Aorto-enteric fistulae and inguinal sinus tracts were observed in both early and late onset infections. Coagulase-negative staphylococci (all slime negative, oxacillin susceptible strains) were the prevalent pathogens in both groups of infections and were isolated in six (32%) patients. Next most commonly seen were Pseudomonas aeruginosa in four (21%) patients, Enterococcus spp. in three (16%) patients, Staphylococcus aureus in three (16%) patients, other bacteria in six (32%) patients. No organisms were isolated in three (16%) patients. Mortality and major amputation rates were 47.3% and 31.6%, respectively. The therapeutic procedures included total graft removal (15 patients), partial graft excision (two patients), partial graft excision followed by total graft removal (one patient) and local treatment without graft removal (one patient). Six patients recovered, including two who underwent total graft removal associated with a non-conventional 'in situ' graft replacement and one patient treated conservatively with local treatment and antibiotics. The three patients undergoing partial graft excision showed signs of active infection of the residual graft.