[Aortofemoral vascular graft infections and their prevention]

Vascular prosthesis infections are potentially severe adverse events following vascular reconstruction. They are often associated with a high morbidity and mortality, especially in the aortofemoral region. The present article outlines the diagnosis, prevention and treatment of vascular graft infections in a clinical setting. The clinical presentation, inflammatory markers, microbiological work-up and imaging studies can contribute to diagnosing a prosthesis infection. Regarding the bacterial spectrum involved in the etiology of prosthesis infections, single organism infections (monoinfections) have become less significant over the past years, whereas infections with multiple organisms now constitute the most abundant microbiological constellation. Also, infections with resistant bacterial strains have been increasing in number over the past years and deserve special consideration. It remains unclear whether both aspects are due to a true epidemiological change or are the result of advanced molecular microbiological diagnostic methods. While during the past decades perioperative antibiotic prophylaxis was regarded as the most important measure for preventing prosthesis infections in vascular surgery, other primary preventive hygiene strategies have been increasingly explored and grouped together in the sense of preventive bundles. In most cases of deep postoperative infections involving a prosthetic device in the aortofemoral region, explantation of the prosthesis will be required. In situ and extra-anatomical reconstructions are often performed in such cases and the decision process to develop an optimal treatment plan must consider several individual factors. In select patients, palliative preservation of the prosthesis despite surrounding infection (i.e. graft salvage) and best conservative management in combination with local surgical measures, such as incision and drainage and vacuum therapy, deserve consideration as a treatment option for patients with a high surgical risk.

Degree of contralateral carotid stenosis improves preoperative risk stratification of patients with asymptomatic ipsilateral carotid stenosis

OBJECTIVE

The benefit of carotid surgery in asymptomatic patients with high-grade internal carotid artery stenosis (ICAS) is subject of intense debate, and thus improved preoperative risk stratification is mandatory. This study aimed to investigate the predictive value of contralateral ICAS (cl-ICAS) for the preoperative clinical presentation of patients with ipsilateral ICAS (primary outcome).

METHODS

This study was a post hoc analysis of a prospective cohort comprising 485 consecutive patients undergoing carotid endarterectomy for high-grade ICAS. Patients were classified by their clinical presentation, ie, asymptomatic (n = 213) or symptomatic (within 6 months of surgery; n = 272, comprising both transient ischemic attack [TIA; n = 163] and stroke [n = 109]). We investigated the association of cl-ICAS with the primary outcome in adjusted regression models.

RESULTS

Mean ipsilateral degrees of ICAS were similar in both groups (84% ± 10% vs 84% ± 11%; P = .92), whereas contralateral degrees were significantly higher in the symptomatic group (29% ± 34% vs 38% ± 39%; P = .008). After multivariable regression analysis, cl-ICAS >60% conferred a three times higher preoperative stroke risk (odds ratio, 3.31; 95% confidence interval, 1.98-5.54; P < .001). Inclusion of cl-ICAS significantly improved (P = .001) ipsilateral combined TIA and stroke risk prediction based on established risk factors (area under the curve, 0.66; 95% confidence interval, 0.60-0.72; P < .001).

CONCLUSIONS

Our study identifies a high contralateral degree of ICAS as an independent predictor of preoperative ipsilateral TIA and stroke in patients with ipsilateral high-grade ICAS. Therefore, such patients might rather benefit from elective carotid surgery and intensive postoperative medical care.

Local anesthesia and exposure for carotid endarterectomy: background and technical realization

While carotid endarterectomy is an established method for the treatment of symptomatic as well as high-grade asymptomatic carotid artery stenoses, there is a considerable variation concerning the kind of anesthesia used as well as technical details of the operation. In the present article differing arguments on local versus general anesthesia as well as a transverse versus a longitudinal skin incision will be discussed. Furthermore, possible access routes to the carotid bifurcation, the retrojugular compared to the ventrojugular approach, will be presented in detail.

Diagnostic accuracy of sigmoidoscopy compared with histology for ischemic colitis after aortic aneurysm repair

Clinically relevant rates of ischemic colitis (IC) causing diarrhea, systemic involvement, colon necrosis, and, ultimately, death by multiple organ failure affect only a small proportion of patients after aortic reconstructions, with reported incidences of 2.7 to 3.3%. The key to treating and saving patients with this complication remains early detection and consequent treatment. The aim of this retrospective analysis of prospectively collected data was to compare the diagnostic accuracy of colonoscopy for detecting postoperative IC compared with histology and to evaluate the interobserver difference of two experienced surgeons. One hundred patients with infrarenal aortic aneurysms, operated on electively from March 2001 to December 2003, who had on postoperative days 3 to 6 a sigmoidoscopy by two independent surgeons and a histologic sample of the sigmoid mucosa, were included in the study. Patients with previous colon resection or inflammatory bowel disease were excluded from the study. All patients gave written informed consent. The study was approved by the Institutional Review Board. Histologic examination of the sigmoid mucosa revealed IC in 13 patients. The combined sensitivity of both investigators for detecting IC by sigmoidoscopy compared with histology was 84%, the specificity was 92.0%, the positive predictive value was 61.1%, the negative predictive value was 97.6%, and the diagnostic accuracy was 91.0%. There was no statistically significant difference between investigator 1 and investigator 2 (p=1.0) and between both investigators and histology (p=.380). Histology remains the gold standard for detecting IC after aortic surgery. Sigmoidoscopy, however, is a valid diagnostic tool allowing immediate clinical decision making with a negative predictive value of more than 94% and a diagnostic accuracy of 92%.

Effects of enoxaparin and unfractionated heparin on platelet activity and reactivity during carotid endarterectomy

The aim of this study was to determine platelet activity and reactivity and the effects of unfractionated heparin (UFH) and enoxaparin on platelet function during carotid eversion endarterectomy under local anesthesia. Twenty symptomatic patients undergoing carotid endarterectomy were randomly assigned to either 5,000 units of UFH or body weight-adjusted enoxaparin (0.5 mg/kg body weight) as an intraoperative intravenous bolus. The activity of platelets was assessed by measuring the expression of CD62p and CD41 with flow cytometry. Additionally, platelet-leukocyte aggregates (PLAs) were enumerated. The reactivity of platelets was evaluated by measuring the expression of the same antigens after stimulation. In addition, platelet reactivity was also analyzed using a PFA-100 analyzer. A significant increase in platelet activity was observed during surgery for CD41 and CD62p (p = .002 and < .001, respectively). The number of PLAs showed no significant changes during surgery. Yet there was a significant difference between patients treated with UFH and patients treated with enoxaparin. No difference for platelet activity or reactivity for patients receiving either UFH or enoxaparin prior to cross-clamping of the carotid arteries was seen. The formation of PLAs after endarterectomy was significantly higher in the UFH group; thus, PLAs are probably a useful surrogate parameter for measuring platelet activity.

Hemodialysis access surgery--is there an increased risk of acquiring hepatitis C virus compared to other elective vascular interventions?

BACKGROUND

To evaluate whether dedicated access surgeons might have a significantly higher risk of acquiring hepatitis C infection compared to other vascular surgeons by assessing the prevalence of hepatitis C patients who are on chronic hemodialysis and to compare the frequency to patients undergoing elective vascular interventions.

PATIENTS AND METHODS

A retrospective chart and data analysis of all patients on chronic hemodialysis was conducted. As a comparative group, the prevalence of anti-HCV antibodies and positive HCV RNA PCR among patients admitted for elective vascular surgery was assessed.

RESULTS

Of 285 patients on chronic hemodialysis, 202 (71%) were had both tests (antibody test for HCV and specific HCV RNA PCR testing). 5% (n = 11; CI 95 = 3-10%) were antibody positive, and 4% (n = 8; CI 95 = 2-8%) were also PCR positive and therefore infectious. One patient was acutely infected. Of 4963 vascular surgical patients, 1141 (23%) had an anti-HCV antibody ELISA test and specific HCV RNA PCR testing. 0.4% (n = 4; CI 95 = 0.1-1%) were antibody positive and 0.2% (n = 2; CI 95 = 0.03-0.7%) were also PCR positive and hence infectious. No acutely infected patient was detected in this population. The chance of operating on a HCV positive and infectious patient among hemodialysis patients was almost 27 times higher than among elective vascular surgical patients (P < 0.0001; OR = 26.56; CI 95 = 5.42-253.40).

CONCLUSIONS

Dedicated hemodialysis access surgeons have a higher risk to acquire hepatitis C infection compared to vascular surgeons performing all other elective vascular surgical interventions. To identify early infected surgeons operating on high risk HCV patient collectives and to start rapid treatment, PCR testing at regular intervals would be advisable.

Homocysteine and Early Re-stenosis after Carotid Eversion Endarterectomy

BACKGROUND

Homocysteine (Hcy) appears to be involved in the development of intimal hyperplasia and arterial thrombosis. The purpose of this study was to evaluate the association of plasma Hcy with early re-stenosis following carotid eversion endarterectomy.

PATIENTS AND METHODS

Of 398 consecutive patients, 363 were included in this study. 62% of patients had symptomatic internal carotid artery (ICA) stenosis. Patients had preoperative assessment of Hcy and other well established atherosclerosis risk factors. Intraoperatively, completion angiography was performed in 2 planes. Patients had clinical, Hcy and duplex follow up at 1, 3, 18 and 36 months postoperatively.

RESULTS

Complete follow up data were available for 312 patients. Five patients suffered from strokes and 2 patients died during the peri-operative period (combined stroke and death rate of 2%). Mean follow up was 26+/-5 months (range 17 to 36 months). Seventeen and six patients (5.5%) developed a 50-69% and >70% re-stenosis, respectively. Serum creatinine was significantly higher in patients with early re-stenosis, occlusion or stroke after CEA (P=0.043). High grade re-stenosis, occlusion and stroke ipsilateral to the operated side (17 patients) was associated with HbA1C and creatinine (P=0.043 and 0.046, respectively) but not Hcy.

CONCLUSION

While Hcy is a recognized independent risk factor for atherothrombosis, our study suggests that there is no association of Hcy with early re-stenosis after eversion endarterectomy.

Replanting the inferior mesentery artery during infrarenal aortic aneurysm repair: influence on postoperative colon ischemia

BACKGROUND

Replanting the inferior mesentery artery (IMA) to prevent ischemic colitis (IC) has been discussed for many years; yet, to our knowledge, no prospective studies have been conducted to compare the incidence of histologically proven IC in patients with and without IMA revascularization. The aim of this prospective study, with histologic evaluation of the sigmoid colon mucosa, was to assess the influence of replanting the IMA on IC and mortality.

METHODS

From January 1999 to December 2003, 160 consecutive patients who were operated on for a symptomatic (n = 21) or asymptomatic (n = 139) infrarenal aortic aneurysm were prospectively assessed and randomly assigned either to replanting or ligating the IMA. Sigmoidoscopy with biopsy was performed on day 4 or 5 after surgery; an autopsy was performed on patients not surviving to day 5 after surgery. All patients gave written informed consent.

RESULTS

Of the 160 randomized patients, 128 had a confirmed patent IMA and formed the basis of this study. Their age was 70 +/- 8 years (men, 70 +/- 8 years; women, 73 +/- 7 years). The IMA was replanted in 67 patients (52%) and ligated in 61 (48%) intraoperatively. IC developed in six patients with a replanted IMA and in 10 with a ligated IMA (relative risk [RR], 0.55; 95% confidence interval [CI], 0.21 to 1.41; chi2 = 1.62; P = .203). Blood loss in the two cohorts did not differ significantly (P = .788); however, patients with IC had a significantly higher blood loss compared with the cohort without IC (P = .012) and were older (P = .017). Age, sex distribution, clamping time, the use of tube or bifurcated grafts, and intraoperative hypotension did not differ between patients with ligated or replanted IMA.

CONCLUSION

Although replanting the IMA did not confer a statistically significant reduction of perioperative morbidity or mortality in this study, it appears that older patients and patients with increased intraoperative blood loss might benefit from IMA replantation, because this maneuver does not increase perioperative morbidity or substantially increase operation time.

Prevalence of patients continuing to smoke after vascular interventions

INTRODUCTION

Smoking is one of the most important risk factors for the development and progression of atherosclerosis. Smoking cessation is an obligatory element in the management of vascular problems and in patients scheduled for vascular interventions. The aim of this study was to assess the prevalence of patients smoking before and after vascular surgical procedures and to evaluate the requirements for inpatient programs for smoking cessation and nicotine replacement therapy.

METHODS

500 patients admitted for vascular interventions were included in this prospective study. Smoking status was evaluated both objectively and subjectively. All patients underwent measurements of exhaled breath carbon monoxide to quantify nicotine dependency and all answered a standardized Fagerström questionnaire both on admission and after surgery to identify current smokers.

RESULTS

Of 500 vascular patients included in the study, only 70 (14 %) never had smoked, 243 (49 %) had given up smoking before admission and 161 (32 %) were current smokers. Of the current smokers, 64 (40 %) did not smoke during hospitalization but 97 (60 %) continued to smoke in hospital. Of these 97 patients, 78 (80 %) were men and 19 women; their mean age was 61 +/- 4 years (range 40-84). Four patients had surgery for infrarenal aortic aneurysm, 40 underwent carotid endarterectomy and 53 had peripheral arterial occlusive disease (PAD). There was no difference between abstinent patients and continuing smokers in previous cigarette consumption or Fagerström score, a predictor for long-term smoking behavior. Patients with carotid artery stenosis were significantly more abstinent while hospitalized (P = 0.006); patients with PAD, however, were more likely to continue smoking as inpatients (P = 0.004). Sixty-five percent of continuing smokers stated that they would stop smoking in hospital if counseling and nicotine replacement therapy were provided. With regard to their predominant location of atherosclerosis, patients with PAD were less willing than those with carotid stenosis to abstain from smoking while hospitalized (53 % vs 88 %, respectively; P < 0.001).

CONCLUSION

A substantial proportion of patients admitted for vascular surgery are smokers. More than half of these continue to smoke in the hospital, an environment where smoking is prohibited by law. Counseling, nicotine replacement therapy and smoking-cessation programs are urgently needed for vascular surgical inpatients.

Antiplatelet therapy prior to carotid endarterectomy – still room for improvement

Background: Antiplatelet therapy is one of the most important modalities for secondary prevention of ischemic events. The aim of this prospective study was to evaluate the current practice of antiplatelet therapy in patients with high grade stenosis of the internal carotid artery (ICA), who were referred by neurologists, stroke physicians and cardiologists for carotid endarterectomy. Patients and methods: Patients referred to our department for carotid endarterectomy with ICA stenosis (> 70% according to NASCET criteria) were prospectively evaluated regarding atherosclerosis risk factors and current antiplatelet therapy. During a 7 month period, 235 patients were scheduled for carotid endarterectomy. Their mean age was 70 years (range 42 years to 95 years), 91 patients were female (39%), 144 male (61%). 122 patients (52%) had a symptomatic ICA stenosis, 113 (48%) an asymptomatic ICA stenosis. Results: Of the 235 patients, 29 were either on low molecular weight heparin or vitamin K antagonists for reasons other than ICA stenosis and were therefore excluded from analysis. Therefore, 206 patients (88%) were evaluated for antiplatelet therapy prescribed by their admitting physicians. Of these patients, 77 (37%) (42 (41%) symptomatic and 35 (34%) asymptomatic patients) did not receive any antithrombotic therapy prior to admission for surgery. The majority of patients received aspirin preoperatively (106 patients, 51.5%) 13 (6%) patients were on clopidogrel and 10 (5%) on dual therapy with Aspirin and clopidogrel. Conclusions: More than one third of patients awaiting carotid endarterectomy did not receive any antiplatelet therapy, despite high grade ICA stenosis. Since this practice does not meet the current guidelines, campaigns to increase the awareness of this problem are urgently needed.

Plasma D-lactate as a potential early marker for colon ischaemia after open aortic reconstruction

BACKGROUND AND AIM

The breakdown of mucosal barrier function due to intestinal hypo-perfusion is the earliest dysfunction of ischaemic colitis. Severe colon ischaemia after aortic reconstruction is associated with mortality rates up to 90%. Therefore, early detection and treatment of patients with extensive ischaemic colitis is of crucial importance. In experimental studies, both D-lactate and bacterial endotoxin have been reported as markers of intestinal mucosal barrier impairment. However, evidence of their value in clinical practice is lacking. The aim of this pilot prospective cohort study was to assess the association between ischaemia of the colon (assessed histologically) and plasma levels of D-lactate and endotoxin in patients undergoing open aortic reconstruction.

PATIENTS AND METHODS

Twelve consecutive patients underwent surgery between February and April 2003. Six patients underwent emergency surgery and six patients elective aortic surgery. D-Lactate and endotoxin levels were measured in blood samples collected according to a standardised protocol. For histological examination biopsies were obtained by sigmoidoscopy on days 4-6 after surgery, or earlier if indicated clinically.

RESULTS

As early as 2 h postoperatively, elevated plasma levels of d-lactate were measured in patients with histologically proven ischaemic colitis. The peak of D-lactate elevation was on postoperative days 1 and 2. Concentration of plasma endotoxin was not significantly different in patients with or without ischaemic colitis.

CONCLUSION

Our data suggest that plasma D-lactate levels are a useful marker for early detection of ischaemic colitis secondary to aortic surgery.

Carotid Endarterectomy Under Local Anaesthesia does not Increase Plasma Homocysteine Concentration

INTRODUCTION

The purpose of this cohort study was to evaluate the effect of carotid endarterectomy under local anaesthesia on homocysteine (Hcy) concentrations.

PATIENTS AND METHODS

Of 100 patients with internal carotid artery (ICA) stenosis >70%, the complete data set was available for 91 patients (39 asymptomatic and 52 symptomatic). All patients underwent eversion endarterectomy of the ICA under regional anaesthesia.

RESULTS

Thirty-two percent of the examined patients had a total Hcy above 15 micromol/l. The mean Hcy levels preoperatively were 13.9+/-4.8 micromol/l. The Hcy levels on day 5 were 13.1+/-5.0 micromol/l and after 6 months 14.0+/-5.8 micromol/l. There was no significant change during follow-up. No intraoperative strokes and deaths were observed and during the 6 months follow-up no recurrent strokes, TIAs or deaths occurred.

CONCLUSION

Patients undergoing carotid endarterectomy under regional anaesthesia do not have an increase in total Hcy postoperatively. This finding is in contrast to results from cardiac surgery and carotid endarterectomy in a recently published animal study, both performing surgery under general anaesthesia.

Antithrombotic Strategies in Vascular Surgery: Evidence and Practice

BACKGROUND

The aim of this study was to evaluate the current practice of peri and postoperative antithrombotic therapy in vascular surgery in Austria and to compare this with the results of randomised prospective clinical trials.

METHODS

A questionnaire assessing intra, postoperative and long-term antithrombotic treatment in 13 different surgical procedures (three supra-aortic, three aorto-iliac reconstructions and seven inguinal and infra-inguinal arterial reconstructions) was sent to all 22 institutions training vascular surgical fellows in Austria.

RESULTS

Intraoperative antithrombotic therapy was quite consistently performed with unfractionated heparin (UFH) with or without acetylsalicylic acid (ASA). Early and long-term postoperative therapy differed considerably. Most centres used low molecular weight heparin (LMWH) for early postoperative therapy after vascular reconstructions, in > 75% combined with ASA and/or clopidogrel. Long-term therapy consisted of antiplatelet agents in all centres. Vascular grafts were anticoagulated with UFH in 25% of the centres in the early postoperative period, the remaining institutions used LMWH +/- antiplatelet agents. For long-term antithrombotic therapy cumarins were used in 75% of the centres, predominantly for venous grafts. Distal prosthetic grafts were mainly treated with antiplatelet agents. Intraoperative antithrombotic therapy was in accordance to present guidelines, postoperative antithrombotic therapy, however, differed considerably between the participating institutions and the results of available controlled studies.

CONCLUSION

Optimal antithrombotic strategies during and after vascular surgery are still under debate, and current practice often differs from available evidence. Vascular surgical societies should be encouraged to define recommendations on antiplatelet therapy and anticoagulation for different vascular interventions.

Combined Open and Endovascular Stent Grafting of Internal Carotid Artery Fibromuscular Dysplasia: Long Term Results

BACKGROUND

Symptomatic fibromuscular dysplasia (FMD) of the internal carotid artery (ICA) can present as thrombo-embolic ischemic events, spontaneous or post-traumatic dissection, aneurysmal degeneration or intracranial haemorrhage and needs definitive surgical treatment.

PATIENTS AND METHODS

Six patients and nine ICA with FMD were revascularised using a carotid approach with minimal exposure of the common, external and internal carotid arteries for covered stent repair. All patients were female, the age ranged from 30 to 65 years (mean 44).

RESULTS

One patient suffered from a perioperative transient neurological deficit. Duplex revealed a patent stent. The patient fully recovered after 5h, not showing any changes on repeat CT scans. One patient developed a recurrent laryngeal nerve palsy. The symptoms gradually resolved within 1 month. No perioperative strokes or deaths occurred. During a mean follow up of 48 months (range 13-63) no thromboembolic neurological events, graft occlusions or haemodynamically significant stenoses occurred.

CONCLUSION

ICA FMD stent grafting is an alternative to open surgery or percutaneous endovascular intervention with excellent long-term results.

Perioperative morbidity and mortality of carotid artery surgery under loco-regional anaesthesia

Background: Loco-regional anaesthesia for carotid artery surgery has many advantages over general anaesthesia. It may be associated with a reduction in neurological, and equally important, non-neurological morbidity and mortality. However, sufficiently powered randomised controlled trials comparing general anaesthesia with local anaesthesia for carotid artery surgery are not yet published. Herein, we present our single centre experience of carotid endarterectomy under local anaesthesia and their respective procedure-related morbidity and mortality rates. Patients and methods: From January 1996 to December 2002, 1271 patients were operated on their carotid arteries. Of these, 1210 (95%) patients and 1355 carotid arteries were operated on in loco-regional anaesthesia and included in a prospective recording. The patients age ranged from 47 to 100 years (mean 70.5 years), 711 patients were male, 499 female. 496 patients (41%) were asymptomatic (Fontaine stage I), 460 have had a transient neurological deficit (TIA) prior to admission (Fontaine stage II) and 254 patients have had a stroke (Fontaine stage IV). Results: The combined stroke rate was 2.2% (n = 30). The overall 30 day mortality was 0.2% (n = 3). The rate of haematoma indicating revision was 3% (n = 40). The revision in all cases was within 12 hours of surgery. No patient developed respiratory insufficiency after surgery. However, of the 40 patients with revision for haematoma, 4 (10%) needed prolonged respiratory assistance and one patient ultimately died of respiratory insufficiency and stroke. No cardiac mortality was observed. The over all rate of myocardial infarction observed postoperatively was 1.4% (n = 19), of which 1.1% (n = 15) were non q-wave infarcts. The combined shunting-rate for all stages was 18.6% (n = 252). Conclusion: Morbidity and mortality of carotid endarterectomy in loco-regional anaesthesia is comparable to recently published single-centre results. Patients with severe COPD, usually unsuitable candidates for general anaesthesia, can also be treated safely.

Renal artery surgery in the era of endovascular intervention

Background: In the last decade the therapeutic concept of renovascular disease has changed. The numbers of primary surgical revascularisations have fallen substantially due to the invention of percutaneous transluminal angioplasty (PTA). Patients and methods: Retrospective data analysis. From September 1992 to December 2001, 42 patients were operated on 49 renal arteries at our institution. During the same period, 166 PTA of renal arteries alone and 92 PTA with stent were performed. Twenty-five patients and 27 renal arteries were operated encompassing an aortic reconstruction due to atherosclerosis (aortic occlusion 14, aortic aneurysm 11). The median age at operation was 61 years (range 47 years to 76 years). Four patients were operated on because of renal artery aneurysms with a diameter of more than 2.5 cm. The median age of these patients was 68.5 years (range 60 years to 77 years). Seven patients presented with atherosclerotic changes of the renal artery without aorto-iliac involvement. Their median age was 62.8 years at operation (range 39 years to 77 years). Of these, one suffered from rupture of the renal artery during PTA and needed emergency surgery. Six patients and 11 renal arteries with FMD were surgically reconstructed. Results: The primary patency rate of all reconstructed renal arteries of surviving patients after 5 years was 92%, the secondary patency rate after 5 years was 98%. Two patients died perioperatively (4.7%). One patient had presented with a symptomatic thoraco-abdominal aneurysm and died ultimately because of a stroke. The second patient had an infrarenal AAA and died after a myocardial infarction. Twenty (47.7%) of all surgically treated patients had had at least one PTA preoperatively. Conclusion: During the last decade, primary surgical renal artery reconstruction was performed in about half of the cases. The decrease of primary open surgery of the renal arteries was most striking in patients with aorto-iliac occlusive disease. From 1996 on no patient of this group underwent open surgery without having had prior PTA of the renal arteries.

Incidence of Cranial Nerve Injuries after Carotid Eversion Endarterectomy with a Transverse Skin Incision under Regional Anaesthesia

OBJECTIVES

The objective of this prospective study was to evaluate the incidence and distribution of cranial nerve injuries after carotid eversion endarterectomy (EEA) performed under regional anaesthesia using a transverse skin incision.

PATIENTS AND METHODS

The study included 165 patients and 180 carotid arteries. All patients had a standard pre-operative assessment performed by a neurologist and ENT specialist. All carotid endarterectomies were performed by the eversion technique under regional anaesthesia.

RESULTS

Ten cranial nerve injuries were observed. Seven patients had injuries of the marginal mandibular branch of the facial nerve, two patients had lesions of the hypoglossal nerve, and one patient had an injury of the recurrent laryngeal nerve. Eleven patients developed hoarseness without cranial nerve injury. Injuries of the marginal mandibular branch recovered after 3-8 months (mean 5.2 months). Both hypoglossal nerve injuries recovered after 4 months. The patient with the recurrent laryngeal palsy had no improvement after 19 months. Patients with hoarseness secondary to laryngeal haematoma recovered within 1 month.

CONCLUSION

The incidence of cranial nerves injury after carotid EEA under regional anaesthesia is comparable to that reported for conventional carotid surgery. Postoperative hoarseness is most frequently due to laryngeal haematoma.

Long-term results of covered stent repair of internal carotid artery dissections

BACKGROUND

Traumatic and spontaneous dissections of internal carotid arteries (ICA) are rare conditions. So far, these pathologies are primarily treated conservatively, surgical revascularization being an option only after recurrent thromboembolic neurologic episodes or continuous aneurysm growth. Successful endovascular treatment strategies with covered stents have been reported in patients with ICA dissections. However, no long-term results are published so far. Herein, we report our experience of a combined conventional and endovascular repair of ICA dissections under reversed flow and their respective long-term results.

METHODS

In a prospective evaluation of clinical and morphologic outcome of 6 patients with carotid artery dissections, 2 patients were treated for continuous aneurysm growth and 4 patients for high-grade ICA stenoses with recurrent thromboembolic episodes during a 6-month follow-up period. A 6-mm polytetrafluoroethylene Hemobahn endoprosthesis was inserted under reversed flow of the internal carotid artery.

RESULTS

No perioperative strokes were observed; one TIA occurred, lasting less than 3 hours; no peripheral cranial nerve injuries or deaths were observed. No occlusions, hemodynamically significant stenosis, or recurrent neurologic symptoms were seen during follow-up, which ranged from 6 to 54 months (mean, 38.3 months).

CONCLUSION

Open endovascular repair of the ICA of symptomatic patients with dissections with a 6-mm covered endoprosthesis is a safe alternative to conventional surgery, with excellent long-term patency.

Gas gangrene due toClostridium perfringens in two injecting drug users in Vienna, Austria

We describe two cases of severe myonecrotic infections caused by Clostridium perfringens in injecting drug users (IDUs) in Vienna, Austria. Clostridial myonecrosis, or gas gangrene, is a clostridial infection primarily of muscle tissue. C. perfringens is isolated in 90% of these infections. Other clostridial species isolated are C. novyi, C. septicum, C. histolyticum, C. fallax, and C. bifermentans. Classically, clostridial myonecrosis has an acute presentation and a fulminant clinical course. It is diagnosed mainly on a clinical basis. The infection may be so rapidly progressive that any delay in recognition or treatment may be fatal. The onset is sudden, often within 4 to 6 hours after an injury. An early clinical finding is sudden severe pain in the area of infection. Swelling and edema in the area of infection is pronounced. At surgery, the infected muscle is dark-red to black, is noncontractile, and does not bleed when cut. Crepitus, although not prominent, is sometimes detected. We were able to demonstrate spores that were morphologically indistinguishable from spores of C. perfringens in a drug sample obtained from case 2. General practitioners and accident and emergency staff should be aware of the possibility of C. perfringens infection in IDUs, especially if injection into soft tissue is suspected.

Bioreductive activation of mitomycin C by DT-diaphorase

The role of DT-diaphorase (DTD, EC 1.6.99.2) in the bioreductive activation of mitomycin C was examined using purified rat hepatic DTD. The formation of adducts with reduced glutathione (GSH), binding of [3H]mitomycin C to DNA, and mitomycin C-induced DNA interstrand cross-linking were used as indicators of bioactivation. Mitomycin C was metabolized by DTD in a pH-dependent manner with increasing amounts of metabolism observed as the pH was decreased from 7.8 to 5.8. The major metabolite observed during DTD-mediated reduction of mitomycin C was 2,7-diaminomitosene. GSH adduct formation, binding of [3H]mitomycin C and mitomycin C-induced DNA interstrand cross-linking were observed during DTD-mediated metabolism. In agreement with the pH dependence of metabolism, increased bioactivation was observed at lower pH values. Temporal studies and experiments using authentic material showed that 2,7-diaminomitosene could be further metabolized by DTD resulting in the formation of mitosene adducts with GSH. DNA cross-linking during either chemical (sodium borohydride) or enzymatic (DTD) mediated reduction of mitomycin C could be observed at pH 7.4, but it increased as the pH was decreased to 5.8, showing the critical role of pH in the cross-linking process. These data provide unequivocal evidence that the obligate two-electron reductase DTD can bioactivate mitomycin C to reactive species which can form adducts with GSH and DNA and induce DNA cross-linking. The use of mitomycin C may be a viable approach to the therapy of tumors high in DTD activity, particularly when combined with strategies to lower tumor pH.