External carotid artery shunting during carotid endarterectomy: an alternative for cerebral protection?

OBJECTIVES: to assess the application of external carotid artery (ECA) shunting in cerebral protection during carotid endarterectomy (CEA). DESIGN: prospective study. MATERIALS AND METHODS: the study comprised 137 consecutive patients who underwent CEA under locoregional anaesthesia. Transcranial Doppler was used to monitor the mean velocity of the middle cerebral artery (mv-MCA): (1) before carotid clamping; (2) after clamping both the common and external carotid arteries; (3) after clamping the internal carotid artery alone ("ECA test"). The decision to shunt was based on the occurrence of neurological deficit during carotid clamping. If the ECA test revealed mv-MCA approaching the pre-clamping values ECA shunting was used, whereas the remaining patients in need of a shunt had a standard internal carotid artery (ICA) shunt. RESULTS: shunting was necessary in 12/137 cases (9%). The ECA test indicated that in four cases - 3% of the whole series or 33% of the shunted cases. In these four patients ECA shunting reversed the neurological deficit, and CEA was successfully performed without any complications. CONCLUSIONS: ECA shunting could be considered as an alternative to standard ICA shunting. Suitable cases can be identified on the basis of the ECA test.     

Can carotid ultrasound predict plaque histopathology?

AIM: European and North American studies have confirmed the benefits of carotid endarterectomy for patients with symptomatic carotid artery stenoses >70%. However, the management of asymptomatic patients and those with lesser degrees of stenosis is less certain. Several studies have suggested that, for these subgroups, the targeting of potentially unstable plaques, may help to identify those most at risk of cerebrovascular accidents and thus most likely to benefit from surgery. The aim of this study was to correlate the ultrasound features of carotid artery stenosis with the histopathological findings of the carotid endarterectomy specimens in order to identify features which will allow preoperative identification of clinically unstable plaques. METHODS: Sixty consecutive patients with symptomatic, critical carotid stenosis were prospectively studied. Plaques were classified preoperatively into one of five types based on their echogenicity and were also assessed for irregularity and ulceration. These findings were then compared with the histopathological findings of the endarterectomy specimen. RESULTS: Of 33 plaques considered on ultrasound to be uniformly or predominantly echolucent (unstable), 27 were found to be largely fatty or haemorrhagic (PPV =82%). Of 17 plaques considered to be predominantly echogenic (stable) on ultrasound, 11 were found to be predominantly fibrotic (PPV = 65%). Correlation between ultrasound irregularity or ulceration and histopathology was poor. CONCLUSION: In routine clinical practice, ultrasound can identify with reasonable accuracy, plaques that are predominantly haemorrhagic or fatty, and therefore potentially unstable. This may have future implications in selection of patients for surgery.     

Are there patients truly at high-risk for carotid endarterectomy or carotid stenting? Can they be identified?

The field of carotid artery revascularization has seen dramatic changes during the past several years, with emergence of carotid artery stenting (CAS) as a treatment alternative to surgical carotid endarterectomy (CEA). CAS enthusiasts have argued that all North American Symptomatic Carotid Endarterectomy Trial (NASCET)-excluded patients are at high-risk (HR) for CEA and, therefore, should be offered stenting instead, accepting or proposing-by implication-that CAS would achieve a better outcome than surgery. The latter is, of course, completely unproved, and the former can be easily refuted through a current reexamination of such NASCET exclusions and of CEA results in contemporary vascular surgery. HR for CEA does exist, however, and relates mainly to anatomic factors, such as hostile neck situations, carotid artery anatomy, and the nature of the carotid lesion. Some serious medical comorbidities constitute valid HR considerations as well. HR for CAS constitutes the "flip-side" of the above-described. Rapidly accumulating evidence points to the fact that certain patients do poorly with carotid stenting, mainly those with recent symptoms of ipsilateral cerebral ischemia, the elderly, and when arch and carotid artery anatomy are unfavorable for endovascular intervention. At present, CEA remains the standard of care for these and the majority of patients with an appropriate indication for carotid revascularization. Despite the general tone of this article and the type of evidence presented, CAS should still be thought of as a very important addition to our armamentarium. But, today it is a procedure to be applied cautiously and only for the right reasons. On the other hand, CAS techniques and technologies will continue to improve and be refined, especially in the areas of access and embolic protection. In the future, we should not be surprised if CAS ultimately reaches a truly competitive level with CEA.     

Is carotid artery stenting equivalent or superior to carotid endarterectomy for treatment of carotid artery stenosis?

A best evidence topic in vascular surgery was written according to a structured protocol. The question addressed was whether carotid artery stenting (CAS) is equivalent or even superior to carotid endarterectomy (CEA) for the treatment of significant carotid artery stenosis. Four hundred and ninety-four papers were identified, of which 14 papers including five randomised controlled trials (RCTs) presented the best evidence to answer the clinical question. The author, journal, date and country of publication, patient group studied, study type, relevant outcomes, results and study weaknesses of these papers are tabulated. We conclude that the risk of peri-procedure stroke or death was similar for patients treated with carotid artery angioplasty+/-stenting and those treated with surgery. However, CAS did reduce the risk of minor complications at the site of vascular access, the incidence of cranial nerve injury, and may reduce economic costs due to shorter hospital stays and earlier return to work. Long term follow-up of these patients is, however, lacking. There are currently four large multi-centre RCTs in progress and their results will determine whether CAS will surpass CEA as the gold standard in the future.     

Does carotid endarterectomy improve cognitive functioning?

BACKGROUND: Carotid endarterectomy (CEA) might improve cognitive functioning, but studies thus far have produced mixed results. The aim of the present study was to examine the effect of CEA on cognitive functions in a methodologically more strict design, first by testing the presumption of preoperative cognitive impairment and second through a better control for the possible influence of the nonspecific effects of practice and surgery. METHODS: Preoperative performance on a neuropsychologic test battery of 56 patients with severe occlusive disease of the carotid artery but without history of major stroke was compared with the performance of 46 healthy control subjects and 23 patients before endarterectomy of the superficial femoral artery (remote endarterectomy). The degree of cognitive change in the 2 patient groups was compared at 3 and 12 months postoperatively. We assessed mood to control for possible momentary affective influences on cognition. RESULTS: Before CEA, patients showed reduced functioning compared with that seen in healthy control subjects in terms of attention, verbal and visual memory, planning of motor behavior, psychomotor skills, and executive function. Performance of patients before remote endarterectomy was reduced as well. Improvements in several cognitive functions were observed after both types of surgical interventions and were attributed to psychologic relief from uncomplicated surgery and to practice. CONCLUSIONS: No specific restorative effect of CEA on cognitive functioning was observed. The preoperative impairment in several cognitive domains might be caused by factors that patients with various types of vascular disease might have in common, such as small-vessel disease or other undetected abnormalities within the brain.     

Can randomized trial outcomes for carotid endarterectomy be achieved in community-wide practice?

The benefit of carotid endarterectomy (CEA) is dependent upon achieving procedural outcomes comparable to those observed in randomized trials. We have extensively examined outcomes of the procedure in the community with a complete medical record (hospital chart) review of over 20,000 Medicare patients undergoing CEA in 10 states. In patients with comparable indications, overall risk of stroke or death of 6.9% in our Medicare studies was comparable to the 6.5% combined event rate in the North American Symptomatic Carotid Endarterectomy Trial. In asymptomatic patients, however, the overall Medicare study result of 3.8% was inferior to the benchmark perioperative combined event rate of 1.5% achieved in the Asymptomatic Carotid Atherosclerosis Study. Our data demonstrated that the randomized trial benchmarks could be achieved or even exceeded at a statewide level. Our studies also documented that evidence-based processes that can reduce perioperative stroke and death (eg, perioperative antiplatelet therapy, patching) are underutilized in the community. Overall process and outcomes assessment show considerable room for improvement. All surgeons performing CEA should use a system-based approach to ensure that all evidence-based processes are employed for patients undergoing CEA and should use indication stratification to document their own outcomes for the procedure.     

Can hypocapnia reduce cerebral embolization during cardiopulmonary bypass?

BACKGROUND: Cerebral embolization is a major cause of central nervous dysfunction after cardiopulmonary bypass. Experimental studies demonstrate that reductions in arterial carbon dioxide tension (PaCO2) can reduce cerebral embolization during cardiopulmonary bypass. This study examined the effects of brief PaCO2 manipulations on cerebral embolization in patients undergoing cardiac valve procedures. METHODS: Patients were prospectively randomized to either hypocapnia (PaCO2 = 30 to 32 mm Hg, n = 30) or normocapnia (PaCO2 = 40 to 42 mm Hg, n = 31) before aortic cross-clamp removal. With removal of the aortic cross-clamp embolic signals were recorded by transcranial Doppler ultrasonography for the next 15 minutes. RESULTS: Despite significant differences in PaCO2, groups did not differ statistically in total cerebral emboli counts. The mean number of embolic events was 107 +/- 100 (median, 80) in the hypocapnic group and 135 +/- 115 (median, 96) in the normocapnic group, respectively (p = 0.315). CONCLUSIONS: Due to the high between-patient variability in embolization, reductions in PaCO2 did not result in a statistically significant decrease in cerebral emboli. In contrast to experimental studies, the beneficial effect of hypocapnia on cerebral embolization could not be demonstrated in humans.     

Does carotid stenting measure up to endarterectomy? A vascular surgeon's experience

HYPOTHESIS: Carotid angioplasty and stenting seems to have equal or better outcomes in high-risk patients than carotid endarterectomy. DESIGN: Single-center case-control study. SETTING: University hospital tertiary referral center. PATIENTS: Individuals (n = 53) undergoing elective carotid angioplasty and stenting for cervical carotid stenosis (n = 57) between April 2001 and October 2003. All patients were referred to and treated by the primary author (M.K.E.). RESULTS: Mean +/- SD age was 68.8 +/- 1.2 years (64% men [34] and 36% women [19]), and overall mean +/- SD rate of stenosis was 79% +/- 10%. Preprocedural neurologic symptoms were present in 42% of the group. Indications for treatment included prior neck surgery with irradiation (4), recurrent stenosis (19), and severe comorbidities (34). Duplex scanning 24 hours after stenting showed immediate mean percentage reductions in peaksystolic velocity and end diastolic velocity of 74% and 76%, respectively. After a 30-day follow-up period, there were no deaths and no major or minor strokes. One patient (1.7%) developed transient amaurosis fugax 12 hours after the procedure. Four patients (7.0%) experienced access-related complications. Intraoperative complications included 1 seizure (1.7%) and 1 asystolic arrest (1.7%), both treated successfully. During follow-up, 3 cases of re-stenosis (5.0%) occurred. One asymptomatic occlusion (1.7%) was detected at the 6-month follow-up visit. There have been no late carotid-related complications or deaths. CONCLUSIONS: Vascular surgeons possessing advanced catheter-based skills can safely perform carotid angioplasty and stenting and can achieve perioperative results comparable with carotid endarterectomy. Determination of the true efficacy and durability of carotid angioplasty and stenting as compared with endarterectomy awaits ongoing randomized national trials.     

Who doesn't receive carotid endarterectomy when appropriate?

OBJECTIVE: The purpose of this study was to identify clinical and nonclinical factors associated with failure to perform carotid endarterectomy (CEA) in patients with clinically appropriate indications. We analyzed data from a prospective cohort study performed at five Veterans Affairs medical centers. Patients were referred for carotid artery evaluation if they had at least 50% stenosis in one carotid artery, had no history of CEA, and were independently classified preoperatively as appropriate candidates for CEA, according to clinical criteria. The primary outcome was receipt of CEA within 6 months of evaluation. Data were collected by medical record review and interview regarding clinical status, and patient and physician perception of the risks and benefits of CEA. RESULTS: Among clinically appropriate candidates for CEA, 66.8% (n = 233) did not undergo the operation. Compared with patients who did undergo CEA, a greater proportion of these patients had no symptoms (68.7% vs 45.7%; P <.001). A twofold greater proportion of patients who did not undergo CEA were in the highest quartile of reported aversion to surgery. Moreover, a fourfold greater proportion were perceived by their physicians to be at less than 5% risk for future stroke without the operation, and more than a twofold greater proportion were believed to experience less than 5% efficacy from the operation by their providers (P <.01). In multivariable analyses, four characteristics were significantly associated with whether an appropriate candidate did not receive CEA: asymptomatic disease, less than 70% stenosis, high expressed aversion to surgery score, and low (<5%) provider-perceived efficacy of the operation. CONCLUSION: Among patients in the Veterans Affairs health care system who are clinically appropriate candidates for CEA, those who did not receive the operation were less likely to have symptomatic disease or high-grade carotid artery stenosis, but were more likely to report high aversion to surgery and to have a provider who believed CEA would not be efficacious.     

Is carotid angioplasty and stenting more cost effective than carotid endarterectomy?

OBJECTIVE: Carotid angioplasty and stenting (CAS) has been advocated as a minimally invasive and inexpensive alternative to carotid endarterectomy (CEA). However, a precise comparative analysis of the immediate and long-term costs associated with these two procedures has not been performed. To accomplish this, a Markov decision analysis model was created to evaluate the relative cost effectiveness of these two interventions. METHODS: Procedural morbidity/mortality rate for CEA and costs (not charges) were derived from a retrospective review of consecutive patients treated at New York Presbyterian Hospital/Cornell (n = 447). Data for CAS were obtained from the literature. We incorporated into this model both the immediate procedural costs and the long-term cost of morbidities, such as stroke (major stroke in the first year = $52,019; in subsequent years = $27,336/y; minor stroke = $9419). We determined long-term survival rate in quality-adjusted life years and lifetime costs for a hypothetic cohort of 70-year-old patients undergoing either CEA or CAS. Our measure of outcome was the cost-effectiveness ratio. RESULTS: The immediate procedural costs of CEA and CAS were $7871 and $10,133 respectively. We assumed major plus minor stroke rates for CEA and CAS of 0.9% and 5%, respectively. We assumed a 30-day mortality rate of 0% for CEA and 1.2% for CAS. In our base case analysis, CEA was cost saving (lifetime savings = $7017/patient; increase in quality-adjusted life years saved = 0.16). Sensitivity analysis revealed major stroke and death rates as the major contributors to this differential in cost effectiveness. Procedural costs were less important, and minor stroke rates were least important. CAS became cost effective only if its major stroke and mortality rates were made equivalent to those of CEA. CONCLUSION: CEA is cost saving compared with CAS. This is related to the higher rate of stroke with CAS and the high cost of stents and protection devices. To be economically competitive, the mortality and major stroke rates of CAS must be at least equivalent if not less than those of CEA.     

Can intraoperative manometry during laparoscopic fundoplication predict postoperative dysphagia?

Background  

Many trials have used intraesophageal manometry (IEM) to measure the adequacy of fundoplication. This pilot study aimed to assess the value of IEM in predicting postoperative dysphagia.     

Are octogenarians at high risk for carotid endarterectomy?

BACKGROUND: Several prospective randomized trials have proved carotid endarterectomy to be safe and effective for both symptomatic and asymptomatic patients younger than 80 years of age. Recently, carotid artery stenting (CAS) has been approved for use in selected high-risk patients. It has been proposed that being an octogenarian places patients in this high-risk category. STUDY DESIGN: All patients between the ages of 80 to 89 years undergoing carotid endarterectomy during a 12-year period were included in the study. Information included indications for carotid endarterectomy, associated risk factors, length of stay, and hospital course. Perioperative morbidity and mortality, including neurologic events and myocardial infarction, were recorded. RESULTS: A total of 103 carotid endarterectomies were performed in 95 octogenarians. Procedures were performed on 59 men and 36 women. Indications for operation included symptomatic carotid stenosis in 44 patients (43%) and asymptomatic carotid stenosis in 59 (57%). Associated risk factors included diabetes mellitus (17%), hypertension (76%), coronary artery disease (28%), hyperlipidemia (39%), and history of smoking (42%). There were 4 perioperative neurologic complications, which included 1 transient ischemic attack (0.97%), 2 minor strokes (1.94%), and 1 major stroke (0.97%). There were no deaths. CONCLUSIONS: Combined end points for adverse events are acceptable in the octogenarian. Carotid endarterectomy remains the gold standard for treatment of extracranial carotid disease in all age groups. Age alone should not place patients in the high-risk category for carotid endarterectomy.