Candidates For Endarterectomy Research Articles

Effect of Vitamin C Infusion on Cerebral Oximetry During General Anesthesia for Carotid Endarterectomy in Diabetic Patients.

There is conflicting information about the effect of vitamin C on brain oxygenation during anesthesia. The current study was designed and performed to assess the effect of vitamin C infusion and brain oxygenation with cerebral oximetry on improving brain perfusion during general anesthesia in vascular surgery of diabetic patients. This randomized clinical trial was performed on patients candidates for endarterectomy under general anesthesia and referred to Taleghani Hospital in Tehran, Iran, during 2019 - 2020. Considering inclusion criteria, the patients were divided into placebo and intervention groups. The patients in the placebo group received 500 mL of isotonic saline. In the intervention group, the patients received 1 g of vitamin C diluted in 500 mL of isotonic saline by infusion half an hour before anesthesia induction. Patients' oxygen levels were continuously measured by a cerebral oximetry sensor. The patients were put in a supine position for 10 minutes before and after anesthesia. At the end of the surgery, the indicators considered in the study were evaluated. No considerable difference was observed between systolic and diastolic blood pressure, heart rate, mean arterial pressure, partial pressure of carbon dioxide, oxygen saturation, regional oxygen saturation, supercritical carbon dioxide, and end-tidal carbon dioxide in total and between the two groups in the three stages before and after anesthesia induction and at the end of surgery (P > 0.05). Additionally, there was no significant difference between blood sugar (BS) levels in the study groups (P > 0.05) but in BS levels at three stages before and after anesthesia induction and at the end of the surgery, with a significant difference (P < 0.05). The amount of perfusion in the two groups and, therefore, in total at the three stages before and after anesthesia induction and at the end of surgery is not different.

Quantitative Detection of Periodontopathogenic Bacteria in Atherosclerotic Plaques from Coronary Arteries by Real-Time PCR

Objectives:Epidemiologic studies have suggested periodontitis as a risk factor for Coronary Artery Diseas (CAD). Detection of periopathogens in atheromatous plaque provides some evidence for the causal relationship between these two conditions. The aim of this study was to determine the presence and quantity of periopathogens in coronary atherosclerotic plaques in patients undergoing Coronary Artery Bypass Graft (CABG) surgery.Methods:20 patients who were candidates for endarterectomy were enrolled in this study for the periodontal examination. Subgingival and coronary atherosclerotic plaque samples were then collected. Thereafter, quantitative detection ofAggregatibacter actinomycetemcomitans (A.a), Porphyromonas gingivali (P.g), and all bacteria detected by Real-Time PCR (RT-PCR) were measured. The correlation analysis was also used to evaluate the relationship between quantities of periopathogens in atherosclerotic and subgingival plaque samples.Results:A.awas detected in 13 patients (65%) with subgingival plaques and 4 patients (20%) with atherosclerotic plaques. In addition,P.gwas found in 15 patients (75%) with subgingival and 10 patients (50%) with atherosclerotic plaques.A.arepresented means of 2.7% and 10.04% of detected bacteria in both atherosclerotic and subgingival plaque samples, respectively. The mean of quantity ofP.gwas 10.85% and 12.87% of the detected bacteria obtained from atherosclerotic and subginigival samples, respectively. Correlation analysis showed a significant correlation between the quantities ofA.ain the atherosclerotic and subgingival plaques, but such a significant relationship was not found forP.g.Conclusion:This study confirmed the detection ofA.aandP.gin atheromatous plaque. The quantitative data suggested that periopathogens comprise a significant proportion of atherosclerotic plaque microbiome, which may consequently contribute to the development of CAD.

Cognitive Deficits in Symptomatic and Asymptomatic Carotid Endarterectomy Surgical Candidates.

The role played by vessel disease in stroke-related cognition dysfunction is unclear. We assessed the impact of significant atherosclerotic disease on cognition-even in patients asymptomatic for stroke. We hypothesized that patients would perform poorly relative to controls, but that symptomatic/asymptomatic status (history of stroke/transient ischemic attack) would have no effect. Fifty-two carotid endarterectomy candidates with >60% carotid stenosis and 17 controls underwent a 60-min neuropsychological test protocol. Symptomatic and asymptomatic patients showed deficits in executive function, delayed verbal recall, and general knowledge. Patients symptomatic for stroke also performed worse on tests of language and motor/visuomotor ability. Symptomatic and asymptomatic patients differed in working memory and language task performance. Although all patients showed deficits in executive function and memory, only symptomatic patients showed additional deficits in language and motor function. Cognitive abnormalities in patients viewed as "asymptomatic" for stroke underscore the need for early identification and treatment.

Predicting Carotid Plaque Characteristics Using Quantitative Color-Coded T1-Weighted MR Plaque Imaging: Correlation with Carotid Endarterectomy Specimens

MR plaque imaging is used to evaluate the risk of embolic complications during carotid endarterectomy and carotid artery stent placement. However, its performance for characterizing intraplaque components has varied across studies and is generally suboptimal. Hence, we correlated MR imaging results with histologic findings to determine whether a combination of high-contrast T1-weighted imaging and quantitative image analysis could readily determine plaque characteristics. We prospectively examined 40 consecutive patients before carotid endarterectomy by using a 1.5T scanner and axial T1-weighted spin-echo images under optimized scanning conditions. The percentage areas of intraplaque fibrous tissue, lipid/necrosis, and hemorrhage were calculated automatically by using the software with previously reported cutoff values and were compared with those of the specimens. The thickness of the fibrous cap was also measured manually. The percentage areas of fibrous, lipid/necrotic, and hemorrhagic components were 5.7%-98.7%, 1.3%-65.7%, and 0%-82.0%, respectively, as determined by the MR images, whereas the corresponding values were 4.8%-92.3%, 7.0%-93.8%, and 0%-70.4%, respectively, as determined by histologic examination. Significant positive correlation and agreement were observed between MR images and histologic specimens (r = 0.92, 0.79, and 0.92; intraclass correlation coefficients = 0.91, 0.67, and 0.89; respectively). Thickness of the fibrous caps on MR images (0.21-0.87 mm) and in the specimens (0.14-0.83 mm) also showed positive correlation and agreement (r = 0.61, intraclass correlation coefficient = 0.59). Quantitative analysis of high-contrast T1-weighted images can accurately evaluate the composition of carotid plaques in carotid endarterectomy candidates.

New strategies in the medical treatment of carotid artery disease

Most patients with ischemic stroke or transient ischemic attack are screened for internal carotid artery stenosis. Although it is important to identify candidates for endarterectomy or stenting, the clinician must realize that most patients are not candidates for revascularization. Therefore, medical therapy remains the cornerstone of treatment. In this article, current thinking on medical therapy for carotid atherosclerosis is outlined, including aggressive use of statins, targeted blood pressure lowering, and antithrombotic therapy. Implementation of these therapies will likely reduce the need for revascularization procedures in the future.

QS43. Are Students Learning What Faculty are Intending to Teach

Introduction: Medical students learn an overwhelming amount of information in a short amount of time, estimated at 13 facts/concepts per hour. (1) in most cases, the lecturer is a medical doctor without formal training in teaching. A great deal of literature has been devoted to assessing how students learn and retain this information. Many authors have concentrated on the format, the length and the appropriate evaluation of the lectures, most commonly evaluated by a post-test. (2-10) Very little research has been dedicated to evaluating free recall of information following a lecture. This study was designed to explore if third year medical students rotating through the general surgery clerkship can demonstrate knowledge gained in a lecture without being prompted by a post-test quiz and to assess if the knowledge gained during a lecture is the same as that which the lecturer identified as a key concept. Methods: Prior to lecturing the third year students during their general surgery clerkship, faculty submitted 3-6 key concepts of their lecture. Immediately following the lecture, students completed an anonymous, paper and pencil evaluation describing 3-6 concepts they learned. The qualitative data was analyzed using QRS’s NVivo. The codebook and coding was performed by two members of the team and discrepancies resolved with the 3rd member. A code was considered significant if more than 5 students reported a similar theme. Each statement was coded as “general”, “specific” or “very specific” intending to measure the depth of the statement. All statements were coded into twelve broad categories such as: basic science, risk factors, symptoms, physical exam, work-up, differential diagnosis, etc. Each session was also coded individually for specific themes. Finally, the student’s themes were compared with the faculty objectives. Results: More than 99% of students were able to name at least one concept they learned from the lecture. The number of students completing surveys ranged from 15-79 per lecture. Most of the statements (n>2300) were very specific or specific as compared to general (<500). During the general coding phase, the five most common themes were related to treatment (n=650), work-up (n=356), prognosis/course of disease (n=327), differential diagnosis (n=286), and indications for treatment (n=242). Four to twenty 20 themes (median 7, mode 7 and mean 8) emerged that were specific to each lecture. For example, during one of the vascular lectures, eighty-nine students commented on indications of carotid endarterectomy (CEA) vs. other treatments. Ten statements were general such as “indications for CEA”, 16 were specific such as “70% stenosis concept”, and most (n=63) were very specific such as “People w/ 50% carotid artery occlusion and symptoms are candidates for endarterectomy; consider co-morbidities for asymptomatic patients”. Congruence between faculty objectives and student’s identification of learning points ranged from 50%-100%. Conclusions: Most students can name something they learned following a lecture, however the depth of the concept learned varied greatly between students. In all lectures, students identified half to all of the objectives provided by the faculty. Many additional themes emerged as key learning concepts to students, some of which had no clinical significance. Future research is warranted to discover specific techniques used during the lecture that influence the number of congruent concepts.

New strategies in the medical treatment of carotid artery disease

Most patients with ischemic stroke or transient ischemic attack are screened for internal carotid artery stenosis. Although it is important to identify candidates for endarterectomy or stenting, the clinician must realize that most patients are not candidates for revascularization. Therefore, medical therapy remains the cornerstone of treatment. In this article, current thinking on medical therapy for carotid atherosclerosis is outlined, including aggressive use of statins, targeted blood pressure lowering, and antithrombotic therapy. Implementation of these therapies will likely reduce the need for revascularization procedures in the future.

Diagnosing Carotid Stenosis by Doppler Sonography

The goal of this review article is to present the state of the art in the clinical applications and technical performance and interpretation of carotid sonographic examinations. Relevant publications regarding color and duplex Doppler sonography (CDDS) of the carotid arteries extracted from a computerized database (MEDLINE) and from references cited in these articles not appearing on the Internet were reviewed. The ability to quickly and efficiently identify stenosis in the carotid artery is an important goal for clinicians and vascular surgeons. Identification of potentially treatable carotid stenosis enables selection of appropriate candidates for endarterectomy or stent implantation. Advances in performance and interpretation of carotid sonographic studies over the last 20 years have been driven by technological improvements in gray scale and CDDS examinations and have made carotid sonography an important means to reach this goal. On the basis of CDDS, intima-media thickness measurements and plaque location and characterization on gray scale imaging, flow disturbance and areas of stenosis on color Doppler sonography, and flow velocities on spectral Doppler sonography are obtained. The degree of the diameter of a stenosis of the internal carotid artery is the main parameter used for therapeutic approaches. Advantages and limitations of the method are included. Carotid sonography is a unique imaging method for the investigation of carotid abnormalities. Noninvasive, accurate, and cost-effective, it provides morphologic and functional information. It is increasingly becoming the first and often the sole imaging study before endarterectomy, whereas costly and invasive procedures are reserved for special cases.

Percutaneous carotid artery stenting: a strategy in evolution

Carotid stenting was initially proposed as an alternative to surgical endarterectomy for selected high-risk patients. More recently, patients of standard surgical risk are being considered for percutaneous treatment of their carotid disease. To describe the clinical outcomes of an initial consecutive cohort of patients treated by carotid stenting at one institution. Between December 1997 and July 2003, 111 patients underwent stenting of 118 carotid arteries. Peri-procedural and long-term outcome data were collected. Most patients (>70%) were high-risk candidates for endarterectomy. Stents were successfully placed in 117/118 carotid arteries (99.2%). Distal protection devices were used in 43/118 (36.4%). The peri-procedural rate of death or disabling stroke was 3/118 (2.5%). Death or any stroke occurred in 11/118 (9.3%). However, only 7/118 (5.9%) procedures resulted in death or any persistent stroke (neurological deficit >1 week post-procedure). No myocardial infarction occurred. Median length of post-procedure hospitalization was 1 day. Long-term follow up was possible for 101 patients (91.0%) over a mean period of 27.1 months. The Kaplan-Meier estimate of survival free of ipsilateral stroke 36 and 66 months after carotid stenting was 77.0 +/- 9.5% and 68.2 +/- 15.1%, respectively. The estimated survival free of any stroke or stent failure was 70.9 +/- 10.7% and 60.7 +/- 17.4%, respectively. The majority of late deaths (7/11) were due to cardiac disease. We conclude that stenting of carotid stenoses is feasible, with a high procedural success rate and low complication rate. Carotid stenting should be considered the procedure of choice for high-risk patients.

A Multiple Regression Model of Combined Duplex Criteria for Detecting Threshold Carotid Stenosis and Predicting the Exact Degree of Carotid Stenosis

Combined duplex criteria are commonly used in vascular laboratories for evaluating carotid stenosis. However, most of these combinations are empirical, and systemic validation is lacking. This study was completed using a multiple regression method to evaluate the accuracy of different combined duplex criteria for detecting threshold carotid stenosis and predicting the exact degree of carotid stenosis on angiography. Two hundred sixty-six sets of unilateral carotid duplex and angiographic data were randomly divided into 2 sets: a derivation set and a validation set. The derivation set was used to develop a multiple logistic regression model for detecting 70% threshold carotid stenosis. Age, sex, systolic blood pressure, diastolic blood pressure, Doppler peak systolic velocity (PSV), Doppler and diastolic velocity (EDV), the systolic carotid ratio (SCR), and ophthalmic artery flow direction were tested as independent variables. A multiple linear regression model was also developed for predicting the exact degree of carotid stenosis on angiogram. The validation set was then used to evaluate the accuracy of these models. According to the logistic regression strategy, the best multiple logistic regression model was as follows: probability of threshold carotid stenosis = exp(2.6 PSV - 6.2)/[1 + exp(2.6 PSV - 6.2)]. The best linear regression model was as follows: degree of carotid stenosis = 20.2 PSV - 7.4 EDV + 0.4 SCR + 8.5. Both models proved to be valid following an evaluation of the validation set. This study illustrates that Doppler parameters may be of use in predicting the exact degree of carotid stenosis and the probability of threshold carotid stenosis. This is important if duplex criteria are going to replace angiography as the only tool for selecting endarterectomy candidates.

Measurement of Carotid Stenosis: Comparisons Between Duplex and Different Angiographic Grading Methods

Endarterectomy has been proved to be an effective stroke prevention procedure. However, there are still inconsistencies between the results of different preoperative evaluation methods, which may sometimes complicate treatment plans. This study measured the discrepancies between different angiographic grading methods and attempted to further assess the accuracy of the carotid duplex examination according to these different angiographic grading methods. One hundred seventy-one preendarterectomy carotid duplex examinations and angiograms were reviewed. All angiograms were measured blindly by one of the authors using the North American Symptomatic Carotid Endarterectomy Trial (N), the European Carotid Surgery Trial (E), and the common carotid (C) methods. The measurement results were further converted into the area of stenosis indices (N2, E2, and C2, respectively). By using regression testing, all results could be compared. The duplex examination data were then compared with the results of different angiographic measurement methods to evaluate their accuracy. The measurement results of all angiographic grading methods were well correlated. Using different angiographic grading systems as the gold standard, duplex examination for screening endarterectomy candidates produced the following results: According to the N method, accuracy was 74%; according to the E method, accuracy was 90%; and according to the C method, the accuracy rate was 92%. According to N2, accuracy was 88%; according to E2, accuracy was 94%; and according to C2, the accuracy rate was 93%. The measurement results of all 3 commonly used angiographic grading methods were linearly correlated with one another. (It is important to note that none of those standards should be treated as the only gold standard.) In this study, the duplex criteria have a greater accuracy rate according to E or C rather than N. However, this study also demonstrated that the cut point of the Doppler criteria is the determinant factor for accuracy rather than which gold standard was compared. Through careful adjustment of the cutoff criteria, carotid duplex can be highly accurate, despite the use of different reference standards.

Cost-effectiveness of screening for carotid stenosis in asymptomatic persons.

The Asymptomatic Carotid Atherosclerosis Study (ACAS) showed that carotid endarterectomy was beneficial for symptom-free patients with carotid stenosis of 60% or more. This finding raises the question of whether widespread screening to identify cases of asymptomatic carotid stenosis should be implemented. To determine whether a screening program to identify cases of asymptomatic carotid stenosis would be a cost-effective strategy for stroke prevention. Cost-effectiveness analysis using published data from clinical trials. General population of asymptomatic 65-year-old men. Patients who were screened for carotid disease with duplex Doppler ultrasonography were compared with patients who were not screened. If ultrasonography found significant carotid stenosis (> or = 60%), disease was confirmed by angiography before carotid endarterectomy was done. Quality-adjusted life-years, costs, and marginal cost-effectiveness ratios. When the conditions and results of ACAS were modeled and it was assumed that the survival advantage produced by endarterectomy would last for 30 years, the lifetime marginal cost-effectiveness of screening relative to no screening was $120,000 per quality-adjusted life-year. Sensitivity analysis showed that marginal cost-effectiveness decreased to $50,000 or less per quality-adjusted life-year only under implausible conditions (for example, if a free screening instrument with perfect test characteristics was used or an asymptomatic population with a 40% prevalence of carotid stenosis was found). Surgery offers a real but modest absolute reduction in the rate of stroke at a substantial cost. A program to identify candidates for endarterectomy by screening asymptomatic populations for carotid stenosis costs more per quality-adjusted life-year than is usually considered acceptable.

Use of Carotid Ultrasound as a Preoperative Assessment of Extracranial Carotid Artery Blood Flow and Vascular Anatomy

Carotid ultrasound evaluation as a preoperative assessment of internal carotid artery blood flow and anatomic stenosis is efficacious and safe. The technique, although operator dependent, is both inexpensive and easily repeated with essentially no risk to the patient. Furthermore, when combined with MR angiography, it usually can obviate the need for angiography in most endarterectomy candidates.

Performance of Carotid Ultrasound in Evaluating Candidates for Carotid Endarterectomy Is Optimized by an Approach Based on Clinical Outcome Rather Than Accuracy

The best method of selecting endarterectomy candidates for cerebral angiography is controversial. Carotid duplex ultrasound (CDUS) is widely used, but its performance varies across institutions. The clinical utility of CDUS could be improved with test criteria based on patient outcome rather than test accuracy. In 155 carotid bifurcations studied by CDUS and cerebral angiography, the degree of angiographic stenosis was measured by a reader, blinded to CDUS, using the North American Symptomatic Carotid Endarterectomy Trial (NASCET) method. We calculated accuracy, sensitivity, and specificity for predicting > or = 70% angiographic carotid stenosis of different peak systolic frequencies (PSF) measured by CDUS and generated a receiver operator characteristic (ROC) curve. We used NASCET outcome data and published data on angiographic complications to define relative "costs" of false-positive and false-negative CDUS, and we determined the point on the ROC curve representing the CDUS criterion with the highest clinical utility. We compared projected morbidity and mortality rates for 1000 hypothetical endarterectomy candidates resulting from the use of the most accurate CDUS criterion versus the CDUS criterion with the highest clinical utility by ROC analysis. While PSF > or = 8 kHz had the highest CDUS accuracy (93%), its projected stroke and death rate due to CDUS error was 10.4/1000. On the other hand, PSF > or = 7 kHz, defined by ROC analysis to have the highest clinical utility, had a lower morbidity and mortality rate of 6.8/1000. The use of ROC analysis and available outcome data can improve the performance of CDUS in selecting endarterectomy candidates for cerebral angiography.

Stent‐Assisted Carotid Percutaneous Transluminal Angioplasty: An Interventional Neuroradiologist's Perspective

There is currently no proof of the long‐term clinical effectiveness of either carotid percutaneous transluminal angioplasty (CPTA) or stent‐assisted carotid percutaneous transluminal angioplasty (SACPTA). Nevertheless, these types of endovascular therapies for carotid revascularization offer several apparent advantages over surgery. Until level I evidence of clinical safety and efficacy is available, however, the application of CPTA or SACPTA should be. restricted to patients considered poor candidates for endarterectomy, or those participating in approved multidisciplinary research initiatives.

Carotid artery stenosis.

Preview Many patients with significant carotid artery stenosis are candidates for endarterectomy, a procedure now proved to reduce the incidence of future stroke and death. In this article, Drs Jaigobin and Perry describe an approach to patients with both symptomatic and asymptomatic carotid stenosis and review current indications for surgical referral. They also emphasize the importance of recognizing and managing concurrent coronary artery disease.

Multicenter review of preoperative risk factors for carotid endarterectomy in patients with ipsilateral symptoms.

Randomized clinical trials have shown that carotid endarterectomy decreases the risk of subsequent stroke in patients with high-grade carotid stenosis and ipsilateral transient ischemic attack or minor stroke. The benefit of surgery is highly dependent on surgical risk. We previously found that patients with ipsilateral hemispheric symptoms were at greater risk of carotid endarterectomy complications compared with those who were asymptomatic or had nonipsilateral symptoms. The goals of the present study were (1) to identify preoperative clinical factors that may increase the risk of complications after carotid endarterectomy in patients with ipsilateral hemispheric symptoms and (2) to develop a risk index based on this patient-level data. Records from 1160 carotid endarterectomies performed at 12 academic medical centers composed the primary data set. Hospital charts for the admission during which carotid endarterectomy was performed were systematically reviewed by abstractors using a defined protocol. The present analysis was carried out on data from the subset of patients who had carotid endarterectomy for ipsilateral hemispheric symptoms. Candidate variables were identified based on univariate Fisher's exact tests or chi 2 tests. A risk index was then developed using those variables with a greater than 90% probability of being associated with adverse outcomes. Of the 697 patients with ipsilateral symptoms, 8.5% had either stroke, myocardial infarction, or died during the postoperative period of hospitalization. Those over the age of 75 had a greater risk of myocardial infarction (6.6% versus 2.3%, P = .024) but not of stroke or death (P > .10). The overall frequencies of adverse outcomes were also higher in the 5 patients with complete ipsilateral carotid occlusions (40% versus 8.2%, P < .01), the 28 patients with ipsilateral intraluminal thrombus (17.9% versus 8.1%, P = .07), and the 65 patients with ipsilateral carotid siphon stenosis (13.9% versus 7.9%, P = .10). There were no differences in adverse outcomes among those with different degrees of ipsilateral stenosis (30% to 49%, 50% to 69%, and 70% to 99%). Adverse outcome rates were similar regardless of the type of symptom (transient ischemic attack, recent ipsilateral minor stroke, remote ipsilateral minor stroke). There were no significant differences in adverse outcome rates based on sex, race, history of angina, recent myocardial infarction, congestive heart failure, chronic obstructive pulmonary disease, hypertension, degree of stenosis of the contralateral carotid artery, or presence of ulceration in the ipsilateral artery (Fisher's exact tests, P > .10). A count of variables with greater than 90% probability of being associated with adverse outcomes (age > or = 75 years or angiographic evidence of ipsilateral carotid occlusion, stenosis in the region of the carotid siphon, or intraluminal thrombus) was used to form a simple risk index. "High-risk" patients (one or more risk factors) had more than two times the risk of complications compared with "low-risk" patients who had no risk factors (odds ratio, 2.18; 95% confidence interval, 1.25 to 3.81). Certain preoperative clinical variables may place patients with ipsilateral symptoms at greater risk of perioperative complications after carotid endarterectomy. Prospective validation of a simple risk index would provide an additional method for assessing preoperative risk in endarterectomy candidates.