Biomedical subjects

R Landis

Publications and source records attributed to R Landis.

At least 19 recordsLinked to original sources

PubMed2002

Endovascular abdominal aortic aneurysm (AAA) repair since the FDA approval. Are we going too far?

BACKGROUND: Since the FDA approval of endovascular devices for abdominal aortic aneurysm (AAA) repair, clinicians have been relaxing the strict inclusion criteria of the clinical trials. We have reviewed our experience during and after the clinical trials to examine changes in patient selection, technical aspects of the procedure, and outcome. METHODS: A review of a prospectively compiled database of all endovascular AAA repairs performed at our institution was performed. RESULTS: Endovascular AAA repair was attempted in 130 patients: 46 (35.4%) as a part of clinical trials (Group I), and 84 (64.6%) since the FDA approval of the devices (Group II). Significant differences in patient selection included: a higher proportion of short (<15 mm) proximal necks in Group II (28.6 vs 0.0%, p<0.001), and a higher proportion of iliac occlusive disease in Group II (48.8 vs 15.4%, p=0.001). Additional trends suggested that Group II AAA's were more complex, including increased proximal neck angulation, increased proximal calcification, increased presence of proximal thrombus, and increased iliac tortuosity. Significant differences in technical aspects of the procedure included increased usage of iliac angioplasty (46.4 vs 13.3%, p<0.001), iliac stenting (31 vs 8.9%, p<0.01), and conduit access to the external iliac artery (10.7 vs 0%, p=0.03) in Group II. Analysis of outcome revealed a decreased incidence of the following in Group II cases: conversions to open repair (2.4 vs 10.9%), lower extremity ischemia (3.6 vs 13.0%), and graft limb occlusion (2.4 vs 8.7%). Other major perioperative complications did not differ significantly between the 2 groups. However, although the overall rate of any endoleak noted in the postoperative course was decreased in Group II cases (26.2 vs 32.6%), the incidence of proximal or distal attachment site leaks has increased (11.9 vs 4.3%, p=0.14). Although this comparison did not reach statistical significance, the magnitude of the increase is concerning. CONCLUSIONS: Although we have been able to offer endovascular AAA repair to a larger number of patients since FDA approval, endovascular management of increasingly complex proximal necks and increased iliac artery disease appears to have increased the incidence of attachment site endoleaks. Although many of these leaks have been successfully managed with adjunctive endovascular procedures, their increasing incidence is worrisome and suggests that we may need to re-evaluate current inclusion criteria for using this technology. Although difficult access issues have been handled with adjunctive procedures, the presence of a short, angulated proximal neck may be difficult to overcome, and may not be well suited for endovascular repair with the currently available devices.

Aortic Aneurysm, Abdominal↗

PubMed2001

Carotid endarterectomy in patients 55 years of age and younger.

Prior studies have suggested that young patients may be more prone to recurrent disease after carotid endarterectomy (CEA). The goal of this study was to review a series of CEAs performed on younger patients (< or = 55 years) and to determine if these patients are more likely to develop recurrent stenosis. A review was conducted of CEAs performed from 1985 through 1994. Analysis was performed on a study group of 94 young patients who underwent 109 CEAs during this time. A control group of 222 patients older than 55 years who underwent 256 CEAs during the years 1991 through 1993 was selected for comparison. During a mean of nearly 4 years of follow-up, younger patients were significantly more likely to experience a late failure of CEA, including total occlusion of the operated artery, or recurrent stenosis requiring redo surgery. Careful patient evaluation is important in choosing younger patients who require CEA. Implications of these data include mandating careful noninvasive follow-up examinations for younger patients undergoing CEA.

Adult↗

PubMed2001

Causes of perioperative stroke after carotid endarterectomy: special considerations in symptomatic patients.

In order to maximize the efficacy of carotid endarterectomy (CEA), the rate of perioperative stroke must be kept to a minimum. A recent analysis of carotid surgery at our institution found that most perioperative strokes were due to technical errors resulting in thrombosis or embolization. From 1992 through 1997 we have performed nearly 1200 additional CEAs; the purpose of this study was to examine recent trends in the causes of perioperative stroke, with specific attention to differences in symptomatic and asymptomatic patients. The records of 1041 patients undergoing 1165 CEAs were reviewed from a prospectively compiled database. Analysis of these data showed that a history of preoperative stroke appears to increase the risk of perioperative stroke after CEA. Surgical factors associated with perioperative stroke include an inability to tolerate clamping, use of an intraarterial shunt, and having surgery performed under general anesthesia; these factors are clearly interrelated and only the use of intraarterial shunting remains a risk factor by multivariate analysis. Over half of all perioperative strokes (54%) appear to be caused by intraoperative or postoperative thrombosis and embolization. The patient requiring use of intraarterial shunting and/or with a preoperative stroke most likely has a significant watershed area of brain at increased risk of infarction. However, technical errors are still the most common cause of perioperative stroke in these high-risk patients. Such high-risk patients may manifest clinical stroke from small emboli that may be tolerated by asymptomatic clamp-tolerant patients. Technical precision and appropriate cerebral protection are particularly critical for successful outcomes in high-risk patients.

Aged↗

PubMed2001

Long-term follow-up of saphenous vein, internal jugular vein, and knitted Dacron patches for carotid artery endarterectomy.

To determine whether choice of material used for patch closure following carotid artery endarterectomy (CAE) influences rates of early or late restenosis, stroke, and death, 274 consecutive CAEs were retrospectively reviewed. Saphenous vein (SV) was used in 159 (58.0%) procedures; everted, double-thickness jugular vein (JV) was used in 25 (9.1%); and knitted Dacron (KD) was used in 90 (32.9%). Primary closure was not used in this series. There were four perioperative strokes: two (1.3%) in SV, one (4%) in JV, and one (1.1%) in KD (NS). Follow-up was obtained on 263 (96%) operated arteries (mean 41.5 months). Duplex scan results were available for 236 (89.7%) of these arteries (mean follow-up time 33.7 months). There were three (2%) late strokes in SV and two (2.2%) in KD (NS). In long-term follow-up, one patient (0.7%) in SV and two (2.4%) in KD developed > 80% stenosis (NS). One patient (0.7%) in SV, one (5.3%) in JV, and one (1.2%) in KD had total occlusion of the operated vessel (NS). Three procedures (2.2%) in SV, 1 (5.3%) in JV, and 7 (8.5%) in KD demonstrated moderate stenosis (50-79%) (NS). Three-year follow-up shows that choice of patch material does not affect early or late stroke rate, stroke-related death rate, rate of high-grade (> 80%) restenosis, or rate of total occlusion. There is a higher incidence of moderate stenosis in KD. Although our results and a review of the literature do not indicate that these patients are at increased risk for symptoms or progression of stenosis, they should be followed by duplex scanning to ensure that this is the case.

Aged↗

PubMed2001

Lower extremity paraparesis or paraplegia subsequent to endovascular management of abdominal aortic aneurysms.

Lower extremity paraplegia or paraparesis is an extremely rare event after operative repair of infrarenal abdominal aortic aneurysms (AAAS). We report two such cases that occurred after endovascular repair or attempted endovascular repair of routine AAAS. To our knowledge, these are the first two cases reported specifically in the literature. These cases may have significant implications with regard to the endovascular management of AAAS, because atheroembolization to the spinal cord appears to be the underlying cause.

Aged↗

PubMed2001

Carotid endarterectomy in female patients: are the concerns of the Asymptomatic Carotid Atherosclerosis Study valid?

OBJECTIVES: Although the results of the Asymptomatic Carotid Atherosclerosis Study clearly demonstrated the benefit of surgical over medical management of severe carotid artery stenosis, the results for women in particular were less certain. This was to some extent because of the higher perioperative complication rate observed in the 281 women (3.6% vs 1.7% in men). The objective of this study was to review a large experience with carotid endarterectomy in female patients and to determine whether the perioperative results differed from those of male patients. METHODS: A review was conducted of a prospectively compiled database on all carotid endarterectomies performed between 1982 and 1997. Operations performed in 991 female patients were compared with those performed in 1485 male patients. RESULTS: Female patients had a significantly lower incidence of diabetes, coronary artery disease, and contralateral carotid artery occlusion than did male patients. Female patients had a significantly higher incidence of hypertension. There were no significant differences in the age, smoking history, anesthetic route, shunt use, or clamp tolerance between the two groups. Of 991 female patients, 659 (66.5%) had preoperative symptoms, whereas 332 (33.5%) cases were performed for asymptomatic stenosis. Among 1485 male patients, 1041 (70.1%) had symptoms, and 444 (29.9%) were symptom free before surgery. There were no significant differences noted in the perioperative stroke rates between men and women overall (2.3% vs 2.4%, P =.92), or when divided into symptomatic (2.5% vs 3.0%, P =.52) and asymptomatic (2.0% vs 1.2%, P =.55) cases. CONCLUSIONS: Carotid endarterectomy can be performed with equally low perioperative stroke rates in men and women in both symptomatic and asymptomatic cases. In this series, symptom-free female patients had the lowest overall stroke rate. The concerns of the Asymptomatic Carotid Atherosclerosis Study regarding the benefit of carotid endarterectomy in female patients should therefore not prevent clinicians from recommending and performing carotid endarterectomy in appropriately selected symptom-free female patients.

Aged↗

PubMed2000

Immediate reexploration for the perioperative neurologic event after carotid endarterectomy: is it worthwhile?

PURPOSE: When managing a new neurologic deficit after carotid endarterectomy (CEA), the surgeon is often preoccupied with determining the cause of the problem, requesting diagnostics tests, and deciding whether the patient should be surgically reexplored. The goal of this study was to analyze a series of perioperative neurologic events and to determine if careful analysis of their timing and mechanisms can predict which cases are likely to improve with reoperation. METHODS: A review of 2024 CEAs performed from 1985 to 1997 revealed 38 patients who manifested a neurologic deficit in the perioperative period (1.9%). These cases form the focus of this analysis. RESULTS: The causes of the events included intraoperative clamping ischemia in 5 patients (13.2%); thromboembolic events in 24 (63.2%); intracerebral hemorrhage in 5 (13.2%); and deficits unrelated to the operated artery in 4 (10.5%). Neurologic events manifesting in the first 24 hours after surgery were significantly more likely to be caused by thromboembolic events than by other causes of stroke (88.0% vs. 12.0%, P<.002); deficits manifesting after the first 24 hours were significantly more likely to be related to other causes. Of 25 deficits manifesting in the first 24 hours after surgery, 18 underwent immediate surgical reexploration. Intraluminal thrombus was noted in 15 of the 18 reexplorations (83. 3%); any technical defects were corrected. After the 18 reexplorations, in 12 cases there was either complete resolution of or significant improvement in the neurologic deficit that had been present (66.7%). CONCLUSIONS: Careful analysis of the timing and presentation of perioperative neurologic events after CEA can predict which cases are likely to improve with reoperation. Neurologic deficits that present during the first 24 hours after CEA are likely to be related to intraluminal thrombus formation and embolization. Unless another etiology for stroke has clearly been established, we think immediate reexploration of the artery without other confirmatory tests is mandatory to remove the embolic source and correct any technical problems. This will likely improve the neurologic outcome in these patients, because an uncorrected situation would lead to continued embolization and compromise.

Aged↗

PubMed1999

Report of a single-institution experience using the EVT endovascular abdominal aortic aneurysm graft in 25 patients.

The purpose of this study was to review a single-institution experience with the Endovascular Technologies [(EVT) Menlo Park, CA] transfemoral, endovascular system of abdominal aortic aneurysm repair. This study was performed at a medical center participating in the phase 1 and phase 2 evaluations of the EVT device. We reviewed the 25 cases performed at our institution. The patient population consisted of 21 males (84%) and 4 females (16%), with a mean age of 73.4 years. A total of eight tube grafts (32%) and 17 bifurcated grafts (68%) were attempted. Twenty-two of the twenty-five grafts were successfully implanted endovascularly (88%). Implantation failures were due to tortuosity or inadequate caliber of the iliac arteries, or incorrect positioning of the graft. The results show that endovascular repair of abdominal aortic aneurysms is an appropriate treatment for selected patients. Conversions to open repair have decreased as experience has grown; careful patient selection can minimize the number of unsuccessful implantations. Patient selection and accurate technique can also minimize the number of endoleaks.

Aged↗

PubMed1999

Redo carotid surgery: An analysis of materials and configurations used in carotid reoperations and their influence on perioperative stroke and subsequent recurrent stenosis.

OBJECTIVE: The ideal method of arterial reconstruction in operations for recurrent carotid disease after prior endarterectomy is unknown. The goal of this study was to review a series of carotid reoperations and to determine whether the surgical technique influenced the rate of perioperative stroke, late stroke, or secondary restenosis. METHODS: A retrospective review was conducted of 82 carotid reoperations performed on 74 patients at our institution. RESULTS: The patient population included 39 men (52.7%) and 35 women (47.3%), with a mean age of 67.5 years. The indications for redo surgery included transient ischemic attack or amaurosis fugax in 35.3% of the patients, stroke in 6.1%, and asymptomatic restenosis (>80%) in 58.5%. Patch angioplasty with or without redo endarterectomy was used in 47 cases (57.3%), with saphenous vein in 26 (31.7%), Dacron in 15 (18.3%), and polytetrafluoroethylene in 6 (7.3%). Interposition grafting was used in 35 cases (42.7%), with saphenous vein in 9 (11.0%), Dacron in 10 (12.2%), and polytetrafluoroethylene in 16 (19.5%). The perioperative complications included three strokes (3.7%). There was a trend toward increased perioperative neurologic complications with interposition grafting when compared with patch angioplasty (8.6% vs 2.1%), although this did not reach statistical significance. Long-term clinical follow-up was obtained in all cases with a mean duration of 35 months, with follow-up duplex scanning performed in 89.2%. The late failures of redo surgery included four significant secondary restenoses and five total occlusions. There was a trend towards improved long-term results with interposition grafting as opposed to patch angioplasty. However, the cases in which reconstruction was performed with a vein had a significantly higher rate of late failures (stroke, secondary recurrent stenosis, or occlusion) than those in which reconstruction was performed with any prosthetic material (26.7% vs 2.3%; P =.002 by Fisher exact test). CONCLUSION: The use of autologous material for redo carotid surgery in any configuration appears to significantly increase the rate of subsequent recurrent stenosis or total occlusion of the operated artery. The reason for this finding is unclear but may be related to both host and technical factors. Prosthetic material may be more durable in the long-term for redo carotid surgery. Interposition grafting for redo carotid surgery may increase the perioperative neurologic complication rate to some degree; however, this was not statistically significant in this series. Interposition grafting may be a more durable solution in long-term follow-up than redo endarterectomy and patch angioplasty. A longer follow-up period will be needed to confirm this conclusion.

Adult↗

PubMed1998

Anesthetic methods in reoperative carotid surgery.

It has been suggested that general anesthesia is the preferred method for reoperative carotid surgery for several reasons, including: the difficulty of the reoperative dissection; the disease may extend unusually high into the internal carotid artery; and the reconstruction required may be more complex than a typical endarterectomy. The purpose of this study is to show that reoperative carotid surgery can be performed safely under regional anesthesia. The records of 109 reoperative carotid operations performed on 96 patients over the past 25 years were reviewed. Procedures performed under regional anesthesia were compared to those performed under general anesthesia with respect to patient characteristics, intraoperative courses, and perioperative results. Regional anesthesia was utilized in 79 operations (72.5%); 30 operations were performed with general anesthesia (27.5%). The two patient groups were essentially equivalent with regard to atherosclerotic risk factors, preoperative neurologic symptoms, and the prevalence of contralateral total occlusion. The etiologies for recurrent disease included recurrent atherosclerosis (50.4%), intimal hyperplasia (30.3%), and vein patch aneurysm (9.2%). The methods of reconstruction employed included saphenous vein patch (47.7%), vein interposition graft (11.9%), prosthetic patch (20.2%), and prosthetic graft (20.2%). Perioperative strokes occurred in one case performed under regional anesthesia (1.3%), and in two cases under general anesthesia (6.6%); this difference was not statistically significant. Reoperative carotid artery surgery can be performed under regional anesthesia safely in the majority of instances. The aforementioned theoretical factors in favor of general anesthesia could also lead to technical difficulties with intraarterial shunt insertion. Having the patient awake, even if just long enough to prove that the patient will tolerate carotid artery clamping, might simplify many of these operations by avoiding shunt insertion. Regional anesthesia should therefore be considered an acceptable option in cases of reoperative carotid surgery.

Anesthesia, Conduction↗

PubMed1997

Causes of the increased stroke rate after carotid endarterectomy in patients with previous strokes.

Patients who have sustained a preoperative stroke are at increased risk for perioperative stroke after carotid endarterectomy. At our institution this risk was recently shown to be increased two-to threefold. The purpose of this study was to investigate the reasons for the increased surgical risk in these patients. Records of 606 patients undergoing 704 consecutive carotid endarterectomies from 1988 through 1993 were reviewed. Patients who suffered preoperative strokes (n = 183) were compared to those who were either asymptomatic or experienced only transient ischemic attacks (TIAs) preoperatively (n = 423). Of the 183 patients who had suffered preoperative strokes, eight patients who experienced perioperative strokes after endarterectomy were compared with 175 who successfully underwent surgery. Patients with a prior stroke had an increased perioperative stroke rate (4.4% versus 1.2%, p = 0.01). They had a significantly higher incidence of hypertension (62.6% versus 47.9%, p < 0.001), cardiac disease (54.7% versus 40.7%, p = 0.001), and positive smoking history (52% versus 40.6%, p = 0.01) than did the asymptomatic/TIA patients. The presence of contralateral total occlusion was also significantly increased (22% versus 10.3%, p < 0.001). Although not statistically significant due to the overall small number of patients who sustained perioperative strokes, the preoperative stroke patients who sustained perioperative strokes had a higher incidence of hypertension (87.5% versus 61.5%) and contralateral total occlusion (37.5% versus 21.3%) than did those who successfully underwent surgery. Patients with both a prior stroke and contralateral total occlusion had a 7.5% perioperative stroke rate. Patients with both a prior stroke and hypertension had a 6.1% perioperative stroke rate. The perioperative strokes in patients with prior strokes were not related to the severity of the prior stroke, the interval between the stroke and surgery, the use of a shunt, or the type of anesthesia employed. Patients who have sustained preoperative strokes have a higher incidence of significant medical illnesses and overall cerebrovascular disease. Hypertension and total occlusion of the contralateral carotid artery appear to be particularly poor prognostic indicators of outcome after endarterectomy in these patients. Patients who have sustained preoperative strokes may be more likely to display clinical neurologic symptoms in response to any form of cerebral ischemia. In this higher risk subgroup, intraoperative and surgeon-dependent factors appear to play less of a role.

Age Factors↗

PubMed1997

Natural history and management of the asymptomatic, moderately stenotic internal carotid artery.

PURPOSE: Although it has been widely accepted as the evidence supporting prophylactic carotid endarterectomy, aspects of the Asymptomatic Carotid Atherosclerosis Study have left unease among clinicians who must decide which individuals without symptoms should undergo surgery. Additional confusion has been created by the fact that the several large randomized trials investigating the efficacy of carotid endarterectomy have classified and analyzed different categories of carotid stenosis. In an effort to provide more information on the natural history of asymptomatic, moderate carotid artery stenosis (50% to 79%), we have reviewed data on approximately 500 arteries. METHODS: Records of our vascular laboratory from 1990 to 1992 were reviewed. We identified 425 patients with asymptomatic, moderate carotid artery stenosis; 71 patients had bilateral stenoses in this category, resulting in 496 arteries for study. RESULTS: The mean length of follow-up was 38 +/- 18 months. New ipsilateral strokes occurred in 16 (3.8%) patients. New ipsilateral transient ischemic attacks occurred in 25 (5.9%) patients. Documented progression of stenosis occurred in 48 (17%) of the 282 arteries for which a repeat duplex examination was available. Arteries that progressed to > 80% stenosis were significantly more likely to have caused strokes than those that remained in the 50% to 79% range (10.4% vs 2.1%, p < 0.02). Conversely, arteries that remained stable in the degree of stenosis were significantly more likely to have remained asymptomatic than those that progressed (92.7% vs 62.5%, p < 0.001). With life-table analysis the estimated cumulative ipsilateral stroke rate was 0.85% at 1 year, 3.6% at 3 years, and 5.4% at 5 years. The respective estimated cumulative transient ischemic attack rates were 1.9%, 5.5%, and 6.3%. The respective estimated cumulative rates for progression of stenosis were 4.9%, 16.7%, and 26.5%. Life-table comparison of ipsilateral stroke revealed a significantly higher cumulative rate among arteries that progressed in the degree of stenosis than among those that remained stable (p < 0.001). CONCLUSIONS: Based on the low rate of permanent neurologic events in these cases, prophylactic carotid endarterectomy for the asymptomatic, moderately stenotic internal carotid artery cannot currently be recommended. The only factor that appears to predict increased risk for future stroke is progression of stenosis. Careful follow-up with serial repeat duplex examinations must be performed in these patients. Until there are widely accepted duplex parameters that can provide all clinicians with accurate identification of arteries with narrowing corresponding to 60% stenosis as defined by the Asymptomatic Carotid Atherosclerosis Study, all surgeons will need to be aware of specifically how their noninvasive laboratories are deriving their results. For the many laboratories that continue to use the University of Washington criteria, 80% should remain the level above which prophylactic carotid endarterectomy is warranted.

Aged↗

PubMed1997

Excess coffee consumption in simulated complex work settings: detriment or facilitation of performance?

Twenty-four managers who normally consume between 400 and 1,000 mg of caffeine per day participated in all-day quasi-experimental simulations. In a crossover, doubleblind design, they made complex managerial decisions either on treatment with their typical daily dose of caffeine or on treatment with 400 mg of caffeine in excess of daily consumption. The effect of caffeine treatment on various validated performance indicators was investigated. The impact of excess caffeine consumption was mild. Increased caffeine facilitated speed of response to incoming information but decreased utilization of opportunity. No significance was obtained for other measures of managerial effectiveness (such as activity, breadth, strategy, and emergency response).

Adult↗

PubMed1996

A comparison of regional and general anesthesia in patients undergoing carotid endarterectomy.

PURPOSE: The optimal anesthetic for use during carotid endarterectomy is controversial. Advocates of regional anesthesia suggest that it may reduce the incidence of perioperative complications in addition to decreasing operative time and hospital costs. To determine whether the anesthetic method correlated with the outcome of the operation, a retrospective review of 3975 carotid operations performed over a 32-year period was performed. METHODS: The records of all patients who underwent carotid endarterectomy at our institution from 1962 to 1994 were retrospectively reviewed. Operations performed with the patient under regional anesthesia were compared with those performed with the patient under general anesthesia with respect to preoperative risk factors and perioperative complications. RESULTS: Regional anesthesia was used in 3382 operations (85.1%). There were no significant differences in the age, gender ratio, or the rates of concomitant medical illness between the two patient populations. The frequency of perioperative stroke in the series was 2.2%; that of myocardial infarction, 1.7%; and that of perioperative death, 1.5%. There were no statistically significant differences in the frequency of perioperative stroke, myocardial infarction, or death on the basis of anesthetic technique. A trend toward higher frequencies of perioperative stroke (3.2% vs 2.0%) and perioperative death (2.0% vs 1.4%) in the general anesthesia group was noted. In examining operative indications, however, there was a significant increase in the percentage of patients receiving general anesthesia who had sustained preoperative strokes when compared with the regional anesthesia patients (36.1% vs 26.4%; p < 0.01). There was also a statistically significant higher frequency of contralateral total occlusion in the general anesthesia group (21.8% vs 15.4%; p = 0.001). The trend toward increased perioperative strokes in the general anesthesia group may be explicable either by the above differences in the patient populations or by actual differences based on anesthetic technique that favor regional anesthesia. CONCLUSIONS: In a retrospective review of a large series of carotid operations, regional anesthesia was shown to be applicable to the vast majority of patients with good clinical outcome. Although the advantages over general anesthesia are perhaps small, the versatility and safety of the technique is sufficient reason for vascular surgeons to include it in their armamentarium of surgical skills. Considering that carotid endarterectomy is a procedure in which complication rates are exceedingly low, a rigidly controlled, prospective randomized trial may be required to accurately assess these differences.

Aged↗

PubMed1995

A comparative study of saphenous vein, internal jugular vein, and knitted Dacron patches for carotid artery endarterectomy.

To determine whether the choice of material used for patch closure following carotid artery endarterectomy (CAE) affected the immediate operative results, the early follow-up results, or the incidence of early restenosis, a retrospective study of 275 consecutive carotid endarterectomies by two vascular surgeons was performed. Among 275 primary CAEs performed between July 1991 and August 1993, 159 (57.8%) were closed with saphenous vein (SV), 25 (9.1%) with double-thickness internal jugular vein (JV), and 91 (33.1%) with knitted Dacron (KD). Primary closure was not used in any of the arteries in this series. The overall perioperative mortality rate was 1.1% and the rate of major and minor morbidity was 4.4% There were four (1.5%) perioperative strokes: two (1.3%) in the SV group, one (4.0%) in the JV group, and one (1.1%) in the KD group. Two-hundred fifty-eight (93.8%) of the 275 endarterectomies were followed postoperatively for 2 to 35 months (mean 14.4). Two-hundred nineteen (79.6%) were evaluated using duplex scans during follow-up with a mean interval of 13.7 months. Of the arteries studied, four (3.6%) in the SV group, none in the JV group, and six (8.4%) in the KD group demonstrated restenosis of > 50% at the time of follow-up (NS). In addition, one (0.9%) artery in the SV group, one (5.6%) in the JV group, and none in the KD group demonstrated complete occlusion. Retrospective analysis of the data showed no statistically significant differences in perioperative morbidity, mortality, or early postoperative restenosis whether the artery was closed with saphenous vein, jugular vein, or knitted Dacron patches. Longer follow-up is needed to determine whether rates of late restenosis and aneurysmal dilation will differ between synthetic and autologous patches.

Aged↗

PubMed1995

Effects of caffeine deprivation on complex human functioning.

Twenty-five managers who reported an average daily caffeine consumption of 575 mg participated in two complex simulations. A double-blind cross-over design was employed to assess the effects of normal caffeine consumption versus caffeine deprivation upon seven validated measures of managerial effectiveness. Data from a Caffeine Withdrawal Questionnaire indicated discomfort upon deprivation. Systolic blood pressure increased during "normal" caffeine consumption levels but fell quickly and remained lower during deprivation. Several measures of managerial performance indicated decreased effectiveness upon caffeine deprivation. In contrast to prior research from simpler task settings, cognitive effectiveness (during complex task performance) was diminished. However, a measure of strategic performance which requires a relatively high level of cognitive effort showed no impact of caffeine deprivation.

Adult↗

PubMed1995

Carotid endarterectomy in the presence of a contralateral occlusion: a review of 315 cases over a 27-year experience.

Recent data from the North American Symptomatic Carotid Endarterectomy Trial revealed a 14.3% perioperative risk of stroke or death with carotid endarterectomy contralateral to a carotid artery occlusion. Since last reporting on this topic in the mid-1980s, the authors have reviewed 180 patients with occlusion of one internal carotid artery (ICA) and who underwent endarterectomy of the stenotic contralateral ICA operated from 1965 to 1984 (group A) compared with 135 operated on from 1985 to 1991. The two groups were similar with respect to age, sex, incidence of coronary artery disease, hypertension, diabetes and history of smoking, but group B had a significantly increased incidence of patients who were neurologically symptom-free before surgery (21.5% versus 7.8%, P < 0.001). The combined perioperative stroke or death rate for patients in group B was significantly lower than for those in group A (0.7% versus 6.7%, P < 0.01). Comparison of the operative techniques showed more frequent placement of intra-arterial shunt (52.6% versus 29.4%, P < 0.001) and increased use of general anesthesia (20.0% versus 9.4%, P < 0.01) in patients of group B. Analysis of the etiology of the complications, however, showed that shunting alone could not account for the improved results. Lower incidences of postoperative thrombosis, embolization and intracerebral hemorrhage were equally important.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Vessel Prosthesis↗

PubMed1995

Alcohol hangover and managerial effectiveness.

Twenty-one male managers who normally drink moderate amounts of alcohol participated in a placebo-controlled, double-blind, cross-over experiment. Subjects consumed either placebo or alcoholic drinks to attain a breath alcohol level of 0.10 during the evening before participation in Strategic Management Simulations. By the time of arrival at the simultaion laboratory on the following morning, breath alcohol levels were measured at 0.00. Questionnaire responses indicated considerable hangover discomfort. Responses to semantic differential evaluative scales suggested that research participants evaluated their own managerial performance in the simulation setting as impaired. However, multiple (validated) measures of decision-making performance obtained in the simulation task did not show any deterioration of functioning. Previous research had shown considerable performance decrements in the same task setting, while blood/breath alcohol levels ranged from 0.05 through 0.10%. Apparently, complex decision-making competence by persons who normally consume moderate amounts of alcohol may not be impaired by hangover caused by intoxication during the previous evening that remains at or below a blood alcohol level of 0.10.

Adult↗