Faculty Bibliography

Systemic administration of dexmedetomidine (DEX) decreases cerebral bloodflow (CBF) via direct alpha-2-mediated constriction of cerebral blood vessels and indirectly via its effect on the intrinsic neural pathway modulating vascular smooth muscle. Reduction in CBF without a concomitant decrease in cerebral metabolic rate has raised concerns that DEX may limit adequate cerebral oxygenation of brain tissue in patients with already compromised cerebral circulation (e.g., carotid endarterectomy [CEA]). In this study, we established the incidence of intraarterial shunting used as a sign of inadequate oxygen delivery in a consecutive series of 123 awake CEA performed in our institution using DEX as a primary sedative. Data were prospectively recorded in 151 patients who underwent CEA during the study period. Eighteen patients were sedated with midazolam and fentanyl (M/F) for medical or logistical reasons. Patients thought to be at risk of an intraoperative stroke were treated with a prophylactic intraarterial shunt. These patients, as well as those who required general anesthesia, were excluded from the final analysis. Five patients (4.3%) in the DEX group required intraarterial shunts. The incidence of shunting in patient undergoing awake CEA in our institution is 10% (historical control). No patients developed a stroke or other serious complications. It appears that the use of DEX as a primary sedative drug for CEA does not increase the incidence of intraarterial shunts

OBJECTIVE: The optimal timing of carotid endarterectomy (CEA) after ipsilateral hemispheric stroke is controversial. Although early studies suggested that an interval of about 6 weeks after a completed stroke was preferred, more recent data have suggested that delaying CEA for this period of time is not necessary. With these issues in mind, we reviewed our experience to examine perioperative outcome with respect to the timing of CEA in previously symptomatic patients. METHODS: A retrospective review of a prospectively maintained database of all CEAs performed at our institution from 1992 to 2003 showed that 2537 CEA were performed, of which 1,158 (45.6%) were in symptomatic patients. Patients who were operated on emergently <or=48 hours of symptoms for crescendo transient ischemic attacks (TIAs) or stroke-in-evolution were excluded from analysis (n = 25). CEA was considered 'early' if performed <or=4 weeks of symptoms, and 'delayed' if performed after a minimum of a 4-week interval following the most recent symptom. RESULTS: Of nonurgent CEAs in symptomatic patients, in 87 instances the exact time interval from symptoms to surgery could not be precisely determined secondary to the remoteness of the symptoms (>18 months), and these were excluded from further analysis. Of the remaining 1,046 cases, 62.7% had TIAs and 37.3% had completed strokes as their indication for surgery. Among the entire cohort, patients who underwent early CEA were significantly more likely to experience a perioperative stroke than patients who underwent delayed CEA (5.1% vs 1.6%, P = .002). Patients with TIAs alone were more likely to be operated on early rather than in a delayed fashion (64.3% vs 46.7%, P < .0001), likely reflecting institutional bias in selecting delayed CEA for stroke patients. However, even when examined as two separate groups, both TIA patients (n = 656) and CVA patients (n = 390) were significantly more likely to experience a perioperative stroke when operated upon early rather than in a delayed fashion (TIA patients, 3.3% vs 0.9%, P = .05; CVA patients, 9.4% vs 2.4%, P = .003). There were no significant differences in demographics or other meaningful variables between patients who underwent early CEA and those who underwent delayed CEA. CONCLUSIONS: In a large institutional experience, patients who underwent CEA <or=4 weeks of ipsilateral TIA or stroke experienced a significantly increased rate of perioperative stroke compared with patients who underwent CEA in a more delayed fashion. This was true for both TIA and stroke patients, although the results were more impressive among stroke patients. On the basis of these results, we continue to recommend that waiting period of 4 weeks be considered in stroke patients who are candidates for CEA

Physicians in residency training will be the referring physicians of tomorrow. We sought to determine the current surgical and medical trainees' perception of vascular surgery's endovascular qualifications and capabilities. An anonymous survey was sent to all general surgery and internal medicine residents at a single academic institution. Respondents answered the question 'Which specialty is the most qualified to perform (1) inferior vena cava (IVC) filter insertion; (2) angiograms, angioplasty, and stenting of the carotid arteries; (3) renal arteries; (4) aorta; and (5) lower extremity arteries?' For each question, respondents chose one response, either vascular surgery, interventional radiology, interventional cardiology, or do not know. One hundred respondents completed the survey (general surgery, n=50; internal medicine, n=50). There was a significant difference in the attitudes of surgery and medicine residents when choosing the most qualified endovascular specialist (p<0.05). Surgery residents chose vascular surgery as the most qualified specialty for each listed procedure: carotid (80%, n=40), IVC (56%, n=28), aorta (100%, n=50), extremity (86%, n=43), renal (78%, n=39). Medicine residents chose vascular surgery as the most qualified specialty less frequently: carotid (66%, n=33), IVC (6%, n=3), aorta (88%, n=44), extremity (72%, n=36), renal (16%, n=8). There was no significant difference in specialty selection based on postgraduate year. There is a large discrepancy between surgical and medical trainees' perception of vascular surgery's endovascular abilities, particularly regarding IVC placement and renal artery interventions. If our own institution mirrors the nation, each passing year a significant portion of the 21,722 graduating internal medicine residents go into practice viewing vascular surgeons as second-tier endovascular providers. A concerted campaign should be undertaken to educate medical residents regarding the skills and capabilities of vascular surgeons

Accurate patient selection based on preoperative imaging is imperative to good risk reduction in patients undergoing carotid endarterectomy (CEA). The goal of this study was to assess the accuracy of gadolinium-enhanced magnetic resonance angiography (GE MRA) versus time-of-flight (TOF) MRA in the work-up of patients undergoing CEA. Patients undergoing CEA between 1999 and 2001 were identified from a prospectively maintained institutional database. GE or TOF MRA was obtained on extracranial carotid arteries (n = 319) in patients undergoing CEA. Stenosis on MRA images was graded as moderate (n = 76) or severe (n = 243) by an attending radiologist who was blind to duplex results. Duplex imaging was performed in an Intersocietal Commission for the Accreditation of Vascular Labs (ICAVL) accredited lab, and stenosis was stratified as moderate (50-79%, n = 76) or high (80-99%, n = 243) grade using University of Washington criteria. For each patient, the degree of stenosis as determined by MRA (GE versus TOF) was compared to percent stenosis on duplex. For moderate-grade lesions, GE MRA concurred with duplex in 11.1% (4/36), underestimated in 2.8% (1/36), and overestimated in 86.1% (31/36) of carotid arteries imaged. TOF MRA concurred with duplex in 35% (14/40), underestimated in 0% (0/40), and overestimated in 65% (26/40) of carotid arteries. High-grade lesions demonstrated improved concordance between MRA and duplex. For these lesions, GE MRA concurred with duplex in 95.6% (130/136) of carotid arteries imaged, never overestimated stenosis (0/136), and underestimated in 4.4% (6/136). TOF MRA concurred with duplex 96.3% (103/107), overestimated stenosis as an occlusion in 0.9% (1/107), and underestimated in 2.8% (3/107). In addition to neck visualization, the GE technique allowed simultaneous aortic arch imaging. This was accomplished in 79.1% (136/172) of all GE MRAs. Simultaneous aortic arch imaging was not technically feasible with TOF MRA. For moderate-grade lesions, both MR techniques are inaccurate predictors of degree of carotid stenosis and result in a significant overestimation of stenosis. Each technique demonstrates improved concordance with duplex ultrasound in the setting of severe carotid artery stenoses. The ability of GE MRA to simultaneously image the aortic arch and the neck may allow for detection of occult tandem lesions and other anatomic variations, which may be particularly important in preoperative planning for carotid artery stenting

OBJECTIVES: Patients with diabetes mellitus have been shown to have an increased incidence of complications after elective major vascular surgery. The objective of this study was to evaluate a large series of diabetic patients undergoing carotid endarterectomy (CEA) to determine if outcome differed from nondiabetic patients and to examine predisposing factors of poor outcome among diabetic patients. METHODS: A retrospective review of a prospectively compiled database was performed. From 1992 through 2000, 2151 CEAs were performed at our institution. Of these, 507 were in diabetic patients (23.6%), and the remaining 1644 procedures were in nondiabetic patients (76.4%). RESULTS: Diabetic patients were significantly more likely than nondiabetic patients to have hypertension (70.8% vs 64.5%, P = .01) and cardiac disease (54.6% vs 49.1%, P = .03). They were more likely than nondiabetic patients to be symptomatic before surgery (52.5% vs 47.1%, P = .04) and to have sustained a preoperative stroke (21.3% vs 17.7%, P = .07). No differences were noted in other recorded demographic factors or in intraoperative factors between diabetic and nondiabetic patients. Despite these differences, diabetic patients had similar perioperative outcomes compared with nondiabetic patients, including perioperative myocardial infarction (0.6% vs 0.4%, P = NS), perioperative death (0.8% vs 0.5%, P = NS), and perioperative neurologic events such as transient ischemic attack and stroke (3.2% vs 2.4%, P = NS). Among diabetic patients alone, cigarette smoking, general anesthesia, the use of a shunt, and the lack of clamp tolerance while under regional anesthesia predicted adverse perioperative neurologic outcome, and contralateral occlusion was associated with increased perioperative mortality. CONCLUSIONS: Despite an increased prevalence of cardiac disease and preoperative neurologic symptoms among diabetic patients undergoing CEA, the rates of perioperative cardiac morbidity, mortality, and stroke were equal to nondiabetic patients. In contrast to nondiabetic patients, current cigarette smoking appeared to predict increased adverse neurologic outcomes among diabetic patients, and the presence of contralateral occlusion among diabetic patients appeared to predispose them towards increased perioperative mortality. The use of a general anesthetic appeared to increased perioperative neurologic risk among diabetic patients; however, this may be related to surgeon bias in the selection of anesthetic technique. Although diabetic patients may have an increase in complications after other major vascular surgical procedures, the presence of diabetes mellitus does not appear to significantly increase risk

INTRODUCTION: Arterial endarterectomy and reconstruction during carotid endarterectomy (CEA) can be performed in a variety of ways, including standard endarterectomy with primary closure, standard endarterectomy with patch angioplasty, and eversion endarterectomy. The optimal method of arterial reconstruction remains a matter of controversy. The objective of this study was to determine the effect of the method of arterial reconstruction during CEA on perioperative outcome. METHODS: A retrospective cohort study of consecutive CEAs performed by 81 surgeons during 1997 and 1998 in six regional hospitals was performed. Detailed clinical data regarding each case and all deaths and nonfatal strokes within 30 days of surgery were ascertained by an independent review of the inpatient chart, outpatient surgeon record, and the hospitals' administrative databases. Two physician investigators--one neurologist and one internist--confirmed each adverse event by independently reviewing patients' medical records. RESULTS: A total of 1972 CEAs were performed. The mean age of the patients was 72.3 years, and 57.2% were male. Preoperative neurologic symptoms occurred in 28.7% of cases (n = 566), and the remaining 71.3% were asymptomatic before surgery (n = 1406). The method of arterial reconstruction was chosen by the surgeon. Primary closure was performed in 11.8% (n = 233), patch angioplasty in 69.8% (n = 1377), and eversion endarterectomy in 18.4% (n = 362). There was no significant difference in the preoperative symptom status of patients who underwent primary closure compared with the other methods of reconstruction (72.5% asymptomatic vs 71.1%, p = NS). Primary closure cases were significantly more likely to experience perioperative stroke compared with the other closure techniques (5.6% vs 2.2%, P = .006). Primary closure cases also had a higher incidence of perioperative stroke or death compared with the other closure techniques (6.0% vs 2.5%, P = .006). There were no significant differences with regard to either perioperative stroke, or perioperative stroke/death noted when comparing patch angioplasty with eversion endarterectomy: stroke, 2.2% vs 2.5% (P = NS) and stroke/death, 2.5% vs 2.5% (P = NS) respectively. CONCLUSION: It appears that primary closure is associated with significantly worse perioperative outcomes compared with endarterectomy with patch angioplasty and eversion endarterectomy, even when the preoperative symptom status of the patient cohorts is equivalent. Although some of its advocates have reported that they can properly select appropriate patients for primary closure based on the size of the artery and other factors, the data demonstrate that these patients have poorer outcomes nonetheless. Primary closure during carotid endarterectomy should predominantly be abandoned in favor of either standard endarterectomy with patch angioplasty or eversion endarterectomy

OBJECTIVE: The net benefit for patients undergoing carotid endarterectomy is critically dependent on the risk of perioperative stroke and death. Information about risk factors can aid appropriate selection of patients and inform efforts to reduce complication rates. This study identifies the clinical, radiographic, surgical, and anesthesia variables that are independent predictors of deaths and stroke following carotid endarterectomy. METHODS: A retrospective cohort study of patients undergoing carotid endarterectomy in 1997 and 1998 by 64 surgeons in 6 hospitals was performed (N = 1972). Detailed information on clinical, radiographic, surgical, anesthesia, and medical management variables and deaths or strokes within 30 days of surgery were abstracted from inpatient and outpatient records. Multivariate logistic regression models identified independent clinical characteristics and operative techniques associated with risk-adjusted rates of combined death and nonfatal stroke as well as all strokes. RESULTS: Death or stroke occurred in 2.28% of patients without carotid symptoms, 2.93% of those with carotid transient ischemic attacks, and 7.11% of those with strokes (P < .0001). Three clinical factors increased the risk-adjusted odds of complications: stroke as the indication for surgery (odds ratio [OR], 2.84; 95% confidence interval [CI] = 1.55-5.20), presence of active coronary artery disease (OR, 3.58; 95% CI = 1.53-8.36), and contralateral carotid stenosis > or =50% (OR, 2.32; 95% CI = 1.33-4.02). Two surgical techniques reduced the risk-adjusted odds of death or stroke: use of local anesthesia (OR, 0.30; 95% CI = 0.16-0.58) and patch closure (OR, 0.43; 95% CI = 0.24-0.76). CONCLUSIONS: Information about these risk factors may help physicians weigh the risks and benefits of carotid endarterectomy in individual patients. Two operative techniques (use of local anesthesia and patch closure) may lower the risk of death or stroke

Endovascular intervention can provide an alternative method of treatment for visceral artery aneurysms. We conducted a retrospective review of all patients with visceral artery aneurysms at a single university medical center from 1990 to 2003, focusing on the outcome of endovascular therapy. Sixty-five patients with visceral artery aneurysms were identified: 39 splenic (SAA), 13 renal, seven celiac, three superior mesenteric (SMA), and three hepatic. Eleven patients (16.9%) had symptoms attributable to their aneurysms, which included a total of four ruptures (6.2%): three splenic and one hepatic. Management consisted of 18 (27.7%) endovascular interventions, nine (13.9%) open surgical repairs, and 38 (58.5%) observations. Mean aneurysm diameter for patients treated expectantly was significantly less than for those who underwent intervention (p = 0.001). Endovascular interventions included 15 (83.3%) embolizations (11 SAA, three renal, one hepatic) and three (16.7%) stent grafts (two SMA, one renal). The initial technical success rate of the endovascular procedures was 94.4% (17/18). However, there were four patients (22.2%) with major endovascular procedure-related complications: one late recurrence requiring open surgical repair, two large symptomatic splenic infarcts, and one episode of severe pancreatitis. These four patients had distal splenic artery aneurysms at or adjacent to the splenic hilum. There were no endovascular procedure-related deaths. Reasons for performing open surgical repair included three SAA ruptures diagnosed at laparotomy and complex anatomy not amenable to endovascular intervention (six patients). One surgical patient had a postoperative small bowel obstruction treated nonoperatively; and there was one perioperative death in a patient operated on emergently for rupture. Endovascular management of visceral artery aneurysms is a reasonable alternative to open surgical repair in carefully selected patients. Individual anatomic considerations play an important role in determining the best treatment strategy if intervention is warranted. However, four of 11 (36.4%) patients with distal splenic artery aneurysms treated with endovascular embolization developed major complications. Based on our experience, traditional surgical treatment of SAA with repair or ligation and concomitant splenectomy when necessary may be preferred in these cases

Objective We compared the physiologic effect of selective atropine administration for bradycardia with routine prophylactic administration, before balloon inflation, during carotid angioplasty and stenting (CAS). We also compared the incidence of procedural bradycardia and hypotension for CAS in patients with primary stenosis vs those with prior ipsilateral carotid endarterectomy (CEA). Methods A total of 86 patients were treated with CAS at 3 institutions. Complete periprocedural information was available for 75 of these patients. The median degree of stenosis was 90% (range, 60%-99%). Indications for CAS were severe comorbidities (n = 49), prior CEA (n = 21), and prior neck radiation (n = 5). Twenty patients with primary lesions were treated selectively with atropine only if symptomatic bradycardia occurred (nonprophylactic group). Thirty-four patients with primary lesions received routine prophylactic atropine administration before balloon inflation or stent deployment (prophylactic group). The 21 patients with prior CEA received selective atropine treatment only if symptomatic bradycardia occurred (prior CEA group) and were analyzed separately. Mean age and cardiac comorbidities did not vary significantly either between the prophylactic and nonprophylactic atropine groups or between the primary and prior CEA patient groups. Outcome measures included bradycardia (decrease in heart rate >50% or absolute heart rate <40 bpm), hypotension (systolic blood pressure <90 mm Hg or mean blood pressure <50 mm Hg), requirement for vasopressors, and cardiac morbidity (myocardial infarction or congestive heart failure). Results The overall incidence of hypotension and bradycardia in patients treated with CAS was 25 (33%) of 75. A decreased incidence of intraoperative bradycardia (9% vs 50%; P < .001) and perioperative cardiac morbidity (0% vs 15%; P < .05) was observed in patients with primary stenosis who received prophylactic atropine as compared with patients who did not receive prophylactic atropine. CAS after prior CEA was associated with a significantly lower incidence of perioperative bradycardia (10% vs 33%; P < .05), hypotension (5% vs 32%; P < .05), and vasopressor requirement (5% vs 30%; P < .05), with a trend toward a lower incidence of cardiac morbidity (0% vs 6%; not significant) as compared with patients treated with CAS for primary carotid lesions. There were no significant predictive demographic factors for bradycardia and hypotension after CAS. Conclusions The administration of prophylactic atropine before balloon inflation during CAS decreases the incidence of intraoperative bradycardia and cardiac morbidity in primary CAS patients. Periprocedural bradycardia, hypotension, and the need for vasopressors occur more frequently with primary CAS than with redo CAS procedures. On the basis of our data, we recommend that prophylactic atropine administration be considered in patients with primary carotid lesions undergoing CAS