Paolo Fiorani

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.

Post-carotid endarterectomy hyperperfusion syndrome: Preliminary observations for identifying at risk patients by transcranial doppler sonography and the acetazolamide test

Patients at risk of hyperperfusion syndrome after carotid endarterectomy are often severely hypertensive and have a high grade internal carotid artery stenosis with disordered autoregulation due to a loss of reserve capacity (RC). Cerebral RC can be studied by sophisticated and expensive technical devices (SPECT, PET). Recently it has been demonstrated that the transcranial Doppler (TCD) and acetazolamide provocation test can be used to assess RC. From September 1991 to January 1992, 36 patients were studied by the TCD and acetazolamide test prior to carotid endarterectomy to identify patients at high risk of the hyperperfusion syndrome. Preoperatively, the patients were studied by TCD at rest and after vasolidation with acetazolamide 1 g intravenously (i.v.). Mean blood flow velocity on the middle cerebral artery (MCAv) was recorded for the following 20 min at 5 min intervals. MCAv at rest was 49 +/- 17 cm/s. After acetzaolamide infusion in 33 patients (92%), the mean MCAv was 62 +/- 19 cm/s with an increase of 19 +/- 13 cm/s (normal RC). In three patients (8%), the mean MCAv was 43 +/- 22 cm/s with a decrease of -6 +/- 3 cm/s with respect to base values (reduction of RC). (t = 3.30; p = 0.0022). All these patients were hypertensive (BP > 180/100 mmHg) and had a carotid artery stenosis > 90%. Postoperatively, the three patients with reduction of RC complained of homolateral headache. TCD showed a mean MCAv of 67 +/- 17 cm/s, an increase compared to the preoperative rest values of 17 +/- 8 cm/s, the 33 patients with normal RC showed a mean change in MCAv -2 +/- 12 cm/s.(ABSTRACT TRUNCATED AT 250 WORDS)

Percutaneous Stenting of the Internal Carotid Artery: The European CAST I Study

Purpose: To report the results of a multicenter safety trial of percutaneous carotid stenting performed by vascular surgeons. Methods: Symptomatic or asymptomatic patients ≥ 65 years of age with internal carotid artery (ICA) stenoses ≥ 70% and ≤ 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.

Detection of aortic graft infection with leukocytes labeled with technetium 99m—hexametazime

PURPOSE To reduce the rates of morbidity and mortality in aortic graft infection, a new diagnostic approach is needed to help identify low-grade stages, specifically when there are minimal or no clinical signs of overt infection. The aim of this study was to evaluate the role of technetium 99m--hexametazime white blood cell scanning (99mTc scanning) in detecting aortic graft infection, particularly in the low-grade stages. METHODS AND RESULTS Thirty-seven patients with suspected aortic graft infection were categorized into three groups according to their signs and symptoms on readmission. Ten patients (group A) had advanced graft infections that were correctly diagnosed by use of computed tomography (CT) scanning and 99mTc scanning and confirmed by intraoperative findings and culture results. Eighteen patients (group B) had nonspecific signs and symptoms of graft infection. Patients only underwent CT and 99mTc scanning for graft infection after standard clinical work-ups failed to reveal disease processes that accounted for the clinical symptoms. In this group of patients 99mTc scanning identified four cases of low-grade graft infection, which was confirmed by intraoperative findings and graft cultures. None of these four cases was confirmed by results of CT scanning. On an average 18-month follow-up in patients who did not undergo surgery graft infections developed. Nine patients (group C) had anastomotic aneurysms; CT scanning and 99mTc scanning correctly diagnosed five patients as being infected. The result of 99mTc scanning was false-positive in one patient. CONCLUSIONS The diagnostic accuracy of 99mTc scanning in patients who did not have specific signs of graft infection (groups B and C) was 100% for sensitivity, 94.4% for specificity, 90% for the positive predictive value, and 100% for the negative predictive value. 99mTc scanning seems to be a useful diagnostic technique for detecting aortic graft infection, particularly in low-grade stages.

Preparation and biodistribution of 99mtechnetium 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.

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.

Comparative study on carotid revascularization (endarterectomy vs stenting) using markers of cellular brain injury, neuropsychometric tests, and diffusion-weighted magnetic resonance imaging.

OBJECTIVE Subclinical alterations of cerebral function can occur during or after carotid revascularization and can be detected by a variety of standard tests. This comparative study assessed the relationship among serum levels for two biochemical markers of cerebral injury, postoperative diffusion-weighted magnetic resonance imaging (DW-MRI), and neuropsychometric testing in patients undergoing carotid endarterectomy (CEA) or carotid artery stenting (CAS) for high-grade asymptomatic carotid stenosis. METHODS Forty-three consecutive asymptomatic patients underwent carotid revascularization by endarterectomy (CEA, 20) or stenting (CAS, 23). They were evaluated with DW-MRI and the Mini-Mental State Examination (MMSE) test preoperatively and <or=24 hours after carotid revascularization. Venous blood samples to assess serum levels of neuron-specific enolase (NSE) and S100beta protein were collected for each patient preoperatively and five times in a 24-hour period postoperatively and assayed using automated commercial equipment. The MMSE test was repeated at 6 months. The relationship between serum marker levels and neuropsychometric and imaging tests and differences between the two groups of patients were analyzed by chi(2) test, with significance at P < .05. RESULTS No transient ischemic attacks or strokes were clinically observed. CAS caused more new subcortical lesions at postoperative DW-MRI and a significant decline in the MMSE postoperative score compared with CEA (P = .03). In CAS patients, new lesions at DW-MRI were significantly associated with a postoperative MMSE score decline >5 points (P = .001). Analysis of S100beta and NSE levels showed a significant increase at 24 hours in CAS patients compared with CEA patients (P = .02). The MMSE score at 6 months showed a nonsignificant increase vs the postoperative score in both groups. CONCLUSIONS Biochemical markers measurements of brain damage combined with neuropsychometric tests and DW-MRI can be used to evaluate silent injuries after CAS. The mechanisms of rise in S100beta and NSE levels at 24 hours after CAS may be due to increased perioperative microembolization rather than to hypoperfusion. Further studies are required to assess the clinical significance of those tests in carotid revascularization.

Contrast-Enhanced Ultrasound Imaging for Aortic Stent-Graft Surveillance

Purpose: To compare unenhanced and enhanced ultrasound imaging to computed tomographic angiography (CTA) or magnetic resonance angiography (MRA) for surveillance of aortic endografts. Methods: Thirty consecutive patients (29 men; mean age 69 years, range 50–82) who underwent endovascular aortic aneurysm repair agreed to participate in a follow-up program. Patients underwent CTA (26/30) or MRA (4/30), plain abdominal radiography, and unenhanced and enhanced ultrasound examinations at 3, 12, and 24 months to evaluate aneurysm diameter, endoleaks, and graft patency. The accuracy of ultrasound was compared with CTA or MRA as the reference standards. Results: Twenty-six patients reached the 24-month assessment (mean follow-up 30 months, range 6–60). All endoleaks detected by CTA or MRA were confirmed by enhanced ultrasound; the aneurysm diameter in these patients remained unchanged or increased. In patients without endoleaks on any imaging method, the sac diameter remained unchanged or decreased. Endoleaks disclosed by enhanced ultrasound alone, all type II, numbered 16 at 3 months, 6 at 12 months, and 3 at 24 months. In this group, the aneurysm diameter remained unchanged or increased. Enhanced ultrasound yielded 100% sensitivity in detecting endoleaks, but compared with CTA and MRA, all endoleaks detected by enhanced ultrasound alone were false positives (mean specificity 65%). Nevertheless, because changes in the postoperative aneurysm diameter were similar in patients with endoleaks detectable on CTA/MRA and on enhanced ultrasound (“true positives”) and in those with endoleaks detectable only on enhanced ultrasound (“false positives”), some endoleaks were possibly “true positive” results. Conclusions: Enhanced ultrasound is a useful method in the long-term surveillance of endovascular aortic aneurysm repairs, possibly in association with CTA or MRA. Enhanced ultrasound also seems able to identify endoleaks missed by other imaging techniques, but this conclusion awaits further investigation.

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.

Diagnosis of vascular graft infections with antibodies against staphylococcal slime antigens

Late-onset infections of synthetic vascular grafts (LO-SVGIs) are generally caused by staphylococci that produce a slime polysaccharide and grow as a biofilm on the graft surface. We developed an ELISA to detect serum antibodies against staphylococcal slime polysaccharide antigens (SSPA). Patients with an ongoing staphylococcal LO-SVGI had greater titres of IgM antibodies against SSPA than did patients in other groups. Antibody titres of 0.40 ELISA units (EU) or more, or 0.35 EU or more detected 97% and 100% of staphylococcal LO-SVGIs, respectively, 0% and 2% titre/unit false-positive results. Our findings suggest that such an ELISA represents a sensitive, specific, and non-invasive diagnostic test for staphylococcal LO-SVGIs.