Distinctive multicystic hemispheric lesions suggesting a novel variant of infantile astrocytoma.

Two unrelated female infants presented at 9 days and 2 months, respectively, with apneic episodes in the former and gaze preference in the latter. MRI revealed enlargement of almost the entire right hemisphere, apparently smooth cortex, simplification of the gyral pattern, and expanded white matter with abnormal signal intensity containing multiple intraparenchymal cysts. Histologic examination of both cases revealed white matter infiltration by a hypocellular lesion composed of uniform, fibrillary astrocytes in a microcystic background. Multilocular tumor cysts were prominent, but Rosenthal fibers and eosinophilic granular bodies were absent. Very rare mitoses were seen in the absence of necrosis or vascular change. There was no convincing cortical infiltration, but the subpial zone was diffusely expanded by a band of astrocytes set in a dense fibrillar feltwork which opened out into numerous cystic spaces. No desmoplastic changes or associated atypical ganglion cells were identified. There was no evidence for a BRAFKIAA1549 fusion or BRAF mutation in one case tested. In conclusion, both lesions are not desmoplastic infantile astrocytoma/ganglioglioma, fibrillary astrocytoma, or typical for pilocytic astrocytoma. Such extreme subpial spread with cysts is most unusual and may suggest a novel variant of infantile astrocytoma.

A comprehensive analysis of high school genetics standards: are states keeping pace with modern genetics?

Science education in the United States will increasingly be driven by testing and accountability requirements, such as those mandated by the No Child Left Behind Act, which rely heavily on learning outcomes, or "standards," that are currently developed on a state-by-state basis. Those standards, in turn, drive curriculum and instruction. Given the importance of standards to teaching and learning, we investigated the quality of life sciences/biology standards with respect to genetics for all 50 states and the District of Columbia, using core concepts developed by the American Society of Human Genetics as normative benchmarks. Our results indicate that the states' genetics standards, in general, are poor, with more than 85% of the states receiving overall scores of Inadequate. In particular, the standards in virtually every state have failed to keep pace with changes in the discipline as it has become genomic in scope, omitting concepts related to genetic complexity, the importance of environment to phenotypic variation, differential gene expression, and the differences between inherited and somatic genetic disease. Clearer, more comprehensive genetics standards are likely to benefit genetics instruction and learning, help prepare future genetics researchers, and contribute to the genetic literacy of the U.S. citizenry.

How to avoid and manage nerve injuries associated with aortic surgery: ischemic neuropathy, traction injuries, and sexual derangements.

Both open and endovascular surgery of the infrarenal aorta are attended by risks of neurologic complications. Injury to the periaortic autonomic plexi frequently results in ejaculatory and erectile dysfunction. Traction injuries to lumbosacral nerve roots can cause peripheral nerve injury, most commonly exhibited as a femoral nerve deficit. The least common but most feared neurologic complication that can occur with infrarenal aortic surgery is ischemic injury to the spinal cord, or conus medullaris. The risk of this complication is increased with emergent or complicated aortic reconstructions. The importance of internal iliac artery perfusion to the development of ischemic cord and nerve root injury has been recognized. Although some neurologic complications may be avoidable by technical modifications, there is a small and probably irreducible neurologic risk to aortic surgery that should be considered when weighing options for treatment of aortic pathology.

Converting from general anesthesia to cervical block anesthesia for carotid endarterectomy.

Between January 1, 1992 and June 30, 1998, vascular and general surgery residents performed 401 carotid endarterectomies (185 cervical block, 216 general anesthesia) under supervision of vascular attending surgeons. In January 1995, cervical block anesthesia was newly instituted. Initially anesthesiologists were randomly assigned to these cases and anesthetic technique was not standardized. At the surgeons' insistence later in the series, three specially trained anesthesiologists routinely administered cervical block anesthesia. As experience grew, surgeons realized that operating time greater than 2 hours and high neck dissections requiring mandibular retraction were poorly tolerated by cervical block anesthesia patients but that repeat carotid endarterectomies could be safely performed. Shunts were selectively inserted if significant electroencephalographic changes occurred or carotid stump pressures were less than 50 mm Hg systolic when general anesthesia was used; neurologic changes occurred when cervical block anesthesia was used; or there was a history of ipsilateral stroke for either anesthetic method. Despite an initial learning curve with cervical block anesthesia, the stroke-mortality rate was similar between the two groups (general anesthesia: 1.9% [four cerebrovascular accidents, two deaths]; cervical block anesthesia: 1.6% [two cerebrovascular accidents, two deaths]). Eight (12%) of the first 66 cervical block anesthesia patients were converted to general anesthesia compared to 2 (1.7%) of the most recent 119 patients with cervical block anesthesia (p = 0.03). After cervical block anesthesia was initiated, seven of the first eight repeat carotid endarterectomies were performed using general anesthesia compared to one of the most recent six repeat cases (p = 0.02). As surgeons' comfort with cervical block anesthesia increased, 94% (100) of the most recent consecutive 106 carotid endarterectomies were performed using this technique. These results suggest that carotid endarterectomy can be performed as safely using cervical block anesthesia as general anesthesia, specialized anesthesiologists are essential to achieve a successful outcome, selected repeat carotid endarterectomies can be performed using cervical block anesthesia, very cephalad lesions are best treated using general anesthesia, and surgical trainees can safely perform carotid endarterectomy under attending surgeon supervision if the operation is carried out expeditiously.

Should duplex ultrasonography be performed for surveillance of femoropopliteal and femorotibial arterial prosthetic bypasses?

Duplex ultrasonography (DU) has been shown to be beneficial for surveillance of lower extremity vein bypasses. However, DU as part of surveillance program for prosthetic grafts is not widely accepted. The purpose of this report was to determine if DU could reliably detect failing prosthetic infrainguinal arterial bypasses and if there were differences in predictability between femoropopliteal (FP) and femorotibial (FT) prosthetic grafts. Between January 1992 and December 1997, 89 infrainguinal grafts in 66 patients were entered into our postoperative prosthetic graft surveillance protocol, which included clinical evaluation, segmental pressures, pulse volume recordings, and DU performed every 3 months. Patients with follow-up of less than 3 months were excluded unless the graft thrombosed. An abnormal DU considered predictive of graft failure included (1) peak systolic velocity (PSV) > 300 cms/sec at inflow or outflow arteries, in the graft or at an anastomosis (unless an adjunctive arteriovenous fistula had been performed); (2) adjacent PSV ratio > 3.0; (3) uniform PSVs < 45 cms/sec; or (4) monophasic signals throughout the graft. DU was considered to have correctly diagnosed a failing graft if a stenosis > 75% the luminal diameter of the graft, at an anastomosis, or in an inflow/outflow artery was confirmed by operative or arteriographic findings or if the graft thrombosed after an abnormal DU but before intervention. Our results support the routine use of DU as a part of a graft surveillance protocol for femorotibial, but not femoropopliteal, prosthetic grafts.

Has arteriography gotten a bad name? Current accuracy and morbidity of diagnostic contrast arteriography for aortoiliac and lower extremity arterial disease.

Recently, contrast arteriography has been challenged as the diagnostic test of choice for lower extremity arterial disease because of its associated morbidity and questionable accuracy in identifying suitable distal outflow arteries. The purpose of this report was to analyze our experience to determine if these concerns were justified. We reviewed 500 consecutive contrast arteriograms performed at our hospital for aortoiliac and lower extremity arterial disease between November 1994 and November 1998. Arteriograms performed in conjunction with therapeutic procedures such as balloon angioplasty, stent placement, and thrombolysis were excluded, leaving 244 diagnostic cases for analysis. Forty-six percent (112) of patients had diabetes mellitus, 14% (34) had an elevated baseline serum creatinine (> or =1.5 mg/dL), and an additional 7% (17) were dialysis dependent. Radiologists limited contrast volume by imaging only the symptomatic extremity when appropriate and using digital subtraction techniques as indicated. Our results showed that diagnostic contrast arteriography is associated with an acceptably low morbidity, has an accuracy that is unlikely to be surpassed by other modalities, and remains the diagnostic test of choice for lower extremity arterial disease.

A strategy to improve quality of outpatient education for residents and medical students on a vascular surgery service.

In the current era of same-day admissions and decreased length of hospitalization for major vascular operations, education of residents and medical students in the outpatient setting has become an increasingly challenging problem. We developed a strategy to provide improved outpatient experience for advanced vascular surgery residents (VSRs), general surgery residents (GSRs), and medical students (MSs) on a vascular surgery service. A survey of program directors and VSRs at accredited vascular surgery fellowships in the United States and Canada was undertaken to determine the manner in which outpatient education was accomplished and the amount of time devoted to pre- and postoperative patient evaluation. The survey revealed that VSRs, GSRs, and MSs spent 1 or more days in clinic at approximately half of accredited vascular surgery programs. There were no appreciable differences in time spent in clinic for different levels of trainees. VSRs preoperatively evaluated at least half of their patients at approximately two-thirds of the programs, while at the other third of the programs they preoperatively evaluated one-quarter or less of their patients before surgery. GSRs preoperatively evaluated at least half of their patients at 50% of programs, according to program directors, and at 69% of programs, according to VSRs. Because of recent changes in health care delivery and the effect of these changes on resident training, outpatient education of VSRs, GSRs, and MSs will require increased attention on the part of vascular surgeons involved with their education. increasing time demands and decreasing reimbursements for vascular surgeons as a result of managed health care may make this goal increasingly difficult to accomplish. Improved strategies and extra efforts are necessary to ensure that trainees obtain sufficient experience to evaluate vascular patients pre- and postoperatively and maintain high quality of care for vascular surgery patients.

Cost-effectiveness and cost-efficiency in vascular surgery.

Medical costs have been an increasing focus of attention in medicine in general, particularly in the United States health care environment. Because vascular disease is most prevalent in the elderly, the forecasted growth of this population over the next several decades will put increasing strains on health care financing. Costs will undoubtedly be a major component of any system of outcomes measurement, and it is important for vascular surgeons and others who specialize in vascular disease to be familiar with the definitions and methodology and cost-effectiveness analysis. Similarly, improving cost efficiency within the practice of vascular surgery will be mandated. The purpose of this article is to review systems of cost-effectiveness analysis as they pertain to vascular surgery, as well as to define critical pathway models that have been used to improve cost-efficiency in vascular surgery.

Abnormal duplex findings at the proximal anastomosis of infrainguinal bypass grafts: does revision enhance patency?

Using color duplex ultrasound (CDU) surveillance of autogenous infrainguinal bypasses, a peak systolic flow velocity (PSFV) ratio of greater than 3 to 1 within the graft relative to adjacent PSFV has been accepted as predicting significant stenosis mandating revision. At the proximal anastomosis, where significant vessel diameter differences and turbulent flow exist, the validity of these criteria is less clear. Our purpose was to review our experience with proximal anastomotic abnormalities in a CDU surveillance protocol. Routine CDU surveillance for all infrainguinal bypass gratis consisted of evaluation in an accredited vascular laboratory at 1 month postoperatively, every 3 months for the first year, every 6 months in the second year, and annually thereafter. Grafts with a PSFV ratio of >3 at the proximal anastomosis on any CDU study were included in this review. From our results we conclude that currently accepted CDU criteria for graft-threatening stenosis may not be valid for abnormalities at the proximal anastomosis of infrainguinal grafts. Regression of these abnormalities is common. Better CDU criteria are needed for predicting not only severity of proximal anastomotic stenosis but also likelihood of graft thrombosis.

Comparison of intraoperative and postoperative duplex ultrasound for carotid endarterectomy.

Intraoperative (IO) duplex ultrasound (DU) is used to identify correctable technical defects at the time of carotid endarterectomy (CEA). Postoperative (p.o.) DU is used to evaluate recurrent or residual stenosis. We compared IO and p.o. DU to determine the value and significance of these studies in the management of patients undergoing CEA. We performed completion IO DU following CEA and p.o. DU a mean of 8 weeks after surgery in 78 patients. IO studies were performed by the operating surgeon and p.o. studies were performed in an accredited vascular laboratory. Peak systolic velocity (PSV) was measured in the internal carotid (ICA), external carotid, and common carotid (CCA) arteries. The criteria used for an abnormal study were an ICA PSV > 150 cm/sec and a ratio of ICA to CCA PSVs(ICA/CCA) > 3.0. Completion angiograms were also performed on all patients intraoperatively. Technical defects identified on DU or angiogram were corrected whenever possible. From our results, we concluded that in many patients, early p.o. DU will demonstrate an elevated ICA PSV compared to the IO PSV. If the ICA/CCA remains normal, this increase is unlikely to represent a clinically relevant recurrent or residual stenosis. A postoperative ICA/CCA ratio > 3.0 may be a more reliable indicator of significant stenosis and a lesion that is likely to progress or occlude than PSVs alone.

Predictors of outcome when reoperating for early infrainguinal bypass occlusion.

The purpose of this study is to identify factors that predict outcome after intervention for early (<30 days) infrainguinal graft thrombosis. We reviewed the medical records, arteriograms, and follow-up studies of patients who underwent infrainguinal bypass for limb salvage between 8/91 and 9/98 and whose graft failed <30 days from the index procedure. Five factors were analyzed: (1) conduit: single segment saphenous vein versus alternative vein or composite conduit (20 vs. 13 patients); (2) repair modality: construction of a new graft at the time of the initial take-back procedure versus local revision and/or thrombectomy alone (12 vs. 21 patients); (3) run-off: good run-off versus poor run-off (20 vs. 13 patients); (4) operative findings: the presence of a correctable problem versus noncorrectable problem (20 vs. 13 patients); and (5) surgical history: previous versus no previous ipsilateral bypass (16 vs. 17 patients). These variables are statistically significant risk factors that can be used in combination to predict outcome. Unless a focal lesion clearly responsible for graft occlusion is found, complete graft replacement should be considered even if the new bypass must be prosthetic. The costs and morbidity of repeated procedures argue for primary amputation when adverse risk factors exist.

Idiopathic pedunculated mural thrombus of the nonaneurysmal infrarenal aorta presenting with popliteal embolization: two cases treated with thrombolytic therapy.

The source of emboli to large or medium sized arteries is most commonly the heart; occasionally, it is an aortic aneurysm. The unusual embolic source of aortic mural thrombus in an otherwise minimally diseased aorta has been infrequently reported, and the etiology and management of this entity are not well defined. We describe two cases of infrarenal aortic mural thrombus treated with thrombolytic therapy and review the published experience with this entity.

Prosthetic patch remnants to treat infected arterial grafts.

PURPOSE: Our previous experience with the traditional management of infected prosthetic arterial grafts, which included graft excision and vein patch repair of the involved artery, was complicated by a high incidence of vein patch rupture. This study assessed the treatment of infected prosthetic grafts with subtotal graft excision and oversewing of small graft remnants. METHODS: During the last 20 years, we treated 53 wounds involving 45 infected prosthetic grafts in 42 patients by means of subtotal graft excision and oversewing of a residual 2- to 3-mm graft remnant (patch) at an intact arterial anastomosis. This technique was selectively used to maintain patency of small-diameter arteries (41 common femoral, five deep femoral, three axillary, two iliac, and two popliteal), which were critical for limb salvage or amputation healing. This strategy avoided difficult dissection of the underlying artery in scarred wounds and obviated the placement of a new patch in an infected field. Graft remnants were polytetrafluoroethylene in 51 cases and Dacron in two cases. Of the 45 grafts, 31 were occluded and 14 were patent. All infected tissue was widely debrided, wet-to-dry dressing changes were performed three times daily, and appropriate intravenous antibiotics were administered for at least 1 week. Secondary bypass grafting procedures were performed as needed to achieve limb salvage. The follow-up period in surviving patients averaged 32 months (range, 1 to 218 months). RESULTS: No complications were directly attributable to prosthetic patch remnants in 92% of cases (49 of 53 cases). Six of 42 patients (14%) died during hospitalization (three of cardiac complications and three of sepsis with multiple organ failure). Two infected pseudoaneurysms developed 8 and 34 months after surgery, and two wounds failed to heal. Sixteen secondary bypass grafting procedures were necessary to achieve limb salvage. Patch oversewing led to limb salvage without the need for secondary revascularization in 26 other cases and to the successful healing of 10 amputated limbs when secondary revascularization was not possible. CONCLUSION: Prosthetic patch remnants are a useful adjunct that simplify management of infected prosthetic grafts, are associated with a low incidence of wound complications, and help maintain patency of essential collaterals to achieve limb salvage or heal an amputation.

Endovascular versus surgical treatment for thrombosed hemodialysis grafts: A prospective, randomized study.

PURPOSE: The objective of this study was to compare clinical outcome and costs for two widely used treatment strategies for hemodialysis graft thrombosis. METHODS: During a 4-year period, 80 patients with thrombosed dialysis grafts were randomly assigned to surgical thrombectomy with or without graft revision (SURG) or thrombolytic therapy with urokinase with the pulse-spray technique (ENDO), with adjunctive percutaneous transluminal angioplasty as indicated. All the procedures were performed in an endovascular operating suite with fistulography. The clinical and cost data were tabulated, and the outcome was analyzed with the life-table method. RESULTS: Fifty-six women and 24 men ranged in age from 33 to 90 years (mean, 63.7 years). The patients had undergone a mean of 2.8 prior access procedures in the ipsilateral extremity. All the grafts were upper extremity expanded polytetrafluoroethylene grafts. Lesions that were presumed to be the primary cause of graft thrombosis were identified in 73 of 80 grafts, and 60 of these were at the venous anastomosis. The procedure time averaged 99 minutes for the patients in the SURG group and 113 minutes for the patients in the ENDO group (P =.12). Eleven patients in the ENDO group crossed over to surgical revision as compared with two patients in the SURG group who required adjunctive percutaneous transluminal angioplasty (P =.005). The mean cost of treatment (including room and supply costs but not professional fees) was significantly higher for the ENDO group than for the SURG group ($2945 vs $1512; P <.001). There were no procedure-related complications in either group. At a median follow-up time of 24 months, there was no difference in primary or assisted primary patency between groups, which averaged 6 and 7 months, respectively. CONCLUSION: Although thrombolytic therapy combined with endovascular treatment can extend the life of dialysis grafts with results similar to surgical revision, there is a high rate of technical failure necessitating surgery and a substantially higher cost for thrombolysis.

Five-step protocol for carotid endarterectomy in the managed health care era.

BACKGROUND: We developed a protocol combining 5 cost-effective strategies to determine whether elective carotid endarterectomy (CEA) could be performed safely without adversely affecting well-established low morbidity and mortality rates and with significant hospital cost savings. METHODS: Between April 1, 1995, and December 31, 1996, 109 of 141 patients were prospectively enrolled as candidates into a 5-step CEA protocol: (1) duplex ultrasonography (DU) performed at an accredited vascular laboratory as the sole diagnostic carotid preoperative study, (2) admission the day of operation, (3) cervical block anesthesia to eliminate intraoperative electroencephalogram monitoring, (4) transfer from the recovery room after a 4-hour observation period to the vascular ward, and (5) discharge the first postoperative morning. The other 32 patients were excluded from analysis; 16 patients were treated by vascular surgeons not participating in the protocol, 9 were treated concomitantly for other medical problems, and 7 were admitted emergently. RESULTS: One patient died of carotid hemorrhage the first postoperative morning, and one had an intraoperative embolic stroke for a combined mortality-stroke rate of 1.8% (2 of 109). Of the 109 patients, 70% (76) underwent operation using DU as the sole diagnostic study, 95% (104) were admitted the day of operation, 76% (83) had cervical block anesthesia, 59% (64) were transferred to the floor the day of operation, and 83% (90) were discharged the morning after operation. None of the 109 patients were adversely affected by these 5 cost-saving strategies except potentially the patient who bled the first postoperative morning. The predicted charges of a patient treated with a perioperative protocol that many vascular surgeons currently use (preoperative arteriography, general anesthesia with intraoperative electroencephalogram monitoring, overnight intensive care unit stay, discharge on postoperative day 2) was $16,073 compared with $10,437 for a patient who completed all 5 steps of the protocol detailed above. CONCLUSIONS: On the basis of these results documenting significant cost savings and acceptably low morbidity and mortality rates, this 5-step protocol may be considered the standard for performing CEA in this era of cost containment. These results may be compared with endovascular intervention, which has recently been proposed as a less expensive technique to treat carotid disease.

Postoperative blood pressure changes associated with cervical block versus general anesthesia following carotid endarterectomy.

The purpose of this report was to determine if cervical block anesthesia (CBA) was associated with fewer hypertensive and hypotensive episodes and decreased need for ICU monitoring following carotid endarterectomy, compared with general anesthesia (GA). A retrospective review of carotid endarterectomies performed using GA (n = 118) versus CBA (n = 116) was carried out and perioperative blood pressure changes and morbidity and mortality rates were analyzed. With increasing emphasis in today's health care market concerning cost containment without sacrificing safety, our results suggest that CBA should be considered preferable to GA for patients undergoing carotid endarterectomy. Fewer significant postoperative hemodynamic changes occurred and costly intensive care monitoring may be avoided.

Revision of failing lower extremity bypass grafts.

BACKGROUND: Color-duplex ultrasound (CDU) surveillance of arterial bypass grafts has been validated, but the natural history of "failing" grafts remains poorly defined. Our purpose was to compare failing grafts having prophylactic revision with those that did not. METHODS: Postoperative duplex surveillance was performed in an accredited vascular laboratory for all lower extremity bypass grafts performed at a single institution. Eighty-five infrainguinal grafts (57 vein, 21 polytetrafluoroethylene (PTFE), and 7 composite grafts) in 83 patients were identified as failing by accepted criteria. Twenty-five grafts were revised early (early), 20 grafts revised more than 2 months after the initial CDU-abnormality (late), and 40 grafts were not prophylactically revised (no revision) at any time. RESULTS: The three groups were not different (P > 0.10) with regard to gender, age, level of bypass, type of conduit, location of stenoses, or timing of abnormality after surgery. No revision patients more frequently had diffuse low peak systolic flow velocity (PSV) as the CDU abnormality (P = 0.013). Cumulative primary patency was significantly better at 12 months (P = 0.028) in the no revision group (78.9%) compared with early grafts (43.1%) or late grafts (63.8%), and this difference remained significant when low PSV grafts were excluded from analysis. However, assisted primary patency, secondary patency, and limb salvage rates did not differ between the three groups (P > 0.10). CONCLUSIONS: Our experience in this retrospective study contradicts other reports supporting the efficacy of prophylactic graft revision for grafts identified as failing by currently accepted CDU criteria. Refinement of CDU criteria to more accurately predict graft thrombosis is needed.

The natural history of "failing" arterial bypass grafts in a duplex surveillance protocol.

Though color duplex ultrasonography (CDU) can identify threatened arterial bypass grafts, the natural history of grafts predicted to fail is not known. We examined patency of "failing grafts" followed by CDU for prolonged periods without intervention. A graft was defined as failing if there was elevation of the peak systolic flow velocity (PSFV) to a ratio of three times the PSFV in the adjacent graft, or if PSFV was less than 45 cm/sec throughout the graft. Only patients followed with CDU abnormalities without intervention for more than 2 months were included. Forty-six CDU abnormalities were noted after construction or revision of lower extremity bypass grafts in 34 patients. Grafts were autogenous in 25 cases, prosthetic in 16, and composite in 5. Focal abnormalities were noted in 35 grafts (76.1%), low PSFV throughout the graft in 6 (13.0%), while both findings were present in 5 grafts (10.7%). For various reasons no intervention was performed during follow-up ranging from 2 to 50 (mean 10) months, during which time patients had a mean of 3.6 CDU studies. Abnormalities regressed in 10 grafts (21.7%), progressed to 5 (10.9%), and were stable in the remainder. Fourteen grafts (30.4%) were ultimately revised with surgery or angioplasty at a mean of 5 months after the first abnormal CDU. Only 3 grafts (6.5%) occluded while being followed. Two of the 3 were among the 5 grafts with both focal elevated PSFV ratio and low PSFV throughout the remaining graft, while all 3 were among the 7 grafts with PSFV ratio in excess of 7.0. Compared to grafts without these features, occlusion was significantly more likely (p = 0.03 and p = 0.001, respectively). Currently defined threshold CDU criteria for prediction of graft failure may be excessively sensitive.