Cytolytic differences among lepidopteran cell lines exposed to toxins of Bacillus thuringiensis subsp. kurstaki (HD-263) and aizawai (HD-112): effect of aminosugars and N-glycosylation

Comparison of lytic-dose response behavior of seven lepidopteran cell lines to the activated delta-endotoxin polypeptides of Bacillus thuringiensis subspecies kurstaki (HD-263) and aizawai (HD-112) indicated distinct differences among the lines. The lines derived from Spodoptera species S. exigua (URC-SE-1A) and S. littoralis (UIV-SL-575) were more susceptible to lysis by aizawai toxin (Bta) than kurstaki toxin (Btk) as were cells from the Lymantria dispar line (IPLB-LD652Y). However, the concentrations of Bta required for lysis of 50% of URC-SE-1A and IPLB-LD652Y cells (LC50) were 0.2 to 0.8 micrograms/ml compared to 5 to 9 micrograms/ml for UIV-SL-575 cells. In comparison, Btk LC50 concentrations for the three lines were similar (14 to 19 micrograms/ml). Cells from S. frugiperda (IPLB-SF-21AE) and Trichoplusia ni (TN368) were similar in their response to Bta (LC50 = 2.5 to 3.7 micrograms/ml) and Btk (LC50 = 1.0 to 2.8 micrograms/ml) whereas the lines derived from Heliothis spp. were the least susceptible to both toxins. The LC50 concentrations for Bta with the H. zea line (IPLB-HA-1075) and H. virescens line (BCIRL-HV-AM1) were > 50 micrograms/ml and for Btk were > 50 micrograms/ml and 42 to 50 micrograms/ml, respectively, yet for both lines Btk was the more cytolytic. Cytolysis of TN368 cells could be inhibited to varying extents by preincubation of the toxins with the aminosugars of galactose, mannose, and glucose and their N-acetyl derivatives. The unsubstituted hexoses were not inhibitory.(ABSTRACT TRUNCATED AT 250 WORDS)

Utility of transesophageal echocardiography in the diagnosis of disease of the thoracic aorta

PURPOSE

Transesophageal echocardiography (TEE) offers a rapid, minimally invasive method for diagnosing thoracic aortic disease. High-resolution images are possible because of the close proximity of the esophagus and vascular structures within the chest. Lung and chest wall components have little influence on the image quality and a virtually unobstructed view of the heart, thoracic aorta, and pulmonary vasculature is seen. The role of TEE in diagnosing diseases of the thoracic aorta is rapidly developing. The purpose of this study is to define the role of TEE in the diagnosis of thoracic aortic disease.

METHODS

Between July 1, 1989 and December 31, 1992, 1005 TEEs were performed at our center. Of these, 199 (125 men, 74 women) were entered into our aortic disease registry. Indications for the studies included 37 referrals to rule out aortic dissection, 18 to assess aortic aneurysm, 55 to assess for an intraaortic source of embolus, 9 to rule out intraaortic thrombus, and 13 with familial hyperlipidemia being followed to mark response to low-density lipoprotein apheresis. In 67 cases, subclinical aortic plaquing was found incidentally. No complications from the TEE procedure were encountered.

RESULTS

In cases of suspected aortic dissection, TEE was equal to computed tomography (CT) scanning in identifying the type (DeBakey) and extent of thoracic aortic dissection. In addition, TEE provided information regarding functional status of the aortic valve, identified interluminal communications, and assessed blood flow and thrombus burden in the false lumen. TEE correctly identified true aneurysms, intraluminal thrombus, and plaques as possible sources of emboli. One false-positive CT scan result for aortic dissection was seen and was ruled out both by TEE and angiography.

CONCLUSION

Biplane TEE can be considered the method of choice in diagnosing disease of the thoracic aorta. Information from TEE can be obtained at the patient's bedside or in the operating suite, to assess surgical results before procedure termination and afterward for follow-up. Adjunctive magnetic resonance imaging, CT scanning, or aortography may be needed to assess extension of the disease process into the abdomen or pelvis or to plan surgical intervention.

Mentholated cigarettes decrease puff volume of smoke and increase carbon monoxide absorption

The influence of mentholated vs. regular cigarettes on selected chemical and topographic parameters was measured in 20 smokers in a pulmonary function laboratory. Half the subjects were black and half were white; half were menthol and half regular smokers. All subjects smoked both types of cigarettes, one on each of 2 days. Compared to regular cigarettes, mentholated cigarettes produced a significantly greater boost in carbon monoxide measured as both blood carboxyhemoglobin and end-expired carbon monoxide, despite the fact that mentholated cigarettes decreased average and total cumulative puff volumes and increased mean puff flow rates of inhaled smoke. These chemical and topographic differences were independent of race. No significant differences in depth of inhalation of the smoke or in the amount of insoluble smoke particulates delivered to or retained in the respiratory tract were noted between the two types of cigarettes. Mentholation of cigarettes may decrease volume of smoke inhaled but appears to increase exposure of smokers to toxic effects of carbon monoxide.

The popliteal artery as inflow for distal bypass grafting

OBJECTIVE

To examine the patency and limb salvage characteristics of the popliteal-distal artery saphenous-vein bypass in patients with minimal superficial femoral artery disease.

DESIGN

A retrospective review.

SETTING

A tertiary care university hospital in the Chicago, Ill, metropolitan area.

PATIENTS

Fifty-two popliteal-distal artery saphenous-vein bypasses for occlusive disease were performed in 51 patients between 1980 and 1993. The mean age at operation was 62 years (range, 37 to 85 years); 34 patients (67%) were male, 45 (88%) were smokers, 44 (86%) had diabetes, and 34 (67%) had coronary disease. The primary indications for operation were gangrene (21 patients [41%]), ulcer (15 patients [29%]), and rest pain (16 patients [31%]).

INTERVENTION

Bypass of diseased arterial segments was performed using popliteal-distal artery saphenous-vein bypass grafts. The proximal anastomoses were either to the above-knee popliteal artery (50%) or to the below-knee artery (50%), with outflow to tibial (79%) or pedal vessels (21%).

MAIN OUTCOME MEASURES

Overall patient survival, limb salvage, and primary and secondary graft patency.

RESULTS

Follow-up of graft patency ranged from 1 day to 11 years (mean follow-up, 2.7 years). The perioperative mortality was 2% and life-table survival was 94% at 1 year, 68% at 5 years, and 50% at 10 years. Primary patency was 90% at 1 month, 82% at 1 year, and 75% at 5 years. There were 14 primary graft failures, only two of which could be traced to progression of proximal disease; five failures occurred less than 30 days after operation. Six of these 14 patients contributed to secondary patency that was 96% at 1 month, 90% at 1 year, and 79% at 5 years. Limb salvage was 96% at 1 month, 90% at 1 year, and 87% at 5 years (seven major amputations were required). No significant differences in patency, limb salvage, or survival were observed on comparison of the level of the proximal or distal anastomosis, type of vein graft, or presence of comorbidities.

CONCLUSIONS

We conclude that popliteal-distal artery bypass provides excellent patency and limb salvage for patients with severe ischemia. The use of a popliteal artery inflow source is preferable in patients with a paucity of venous segments since progression of proximal disease rarely leads to graft failure.

Femorofemoral bypass for aortofemoral graft limb occlusion: a ten-year experience

PURPOSE

Aortofemoral bypass (AFB) is a durable reconstruction; however, graft limb occlusion occurs in 10% to 20% of patients and results in limb ischemia. Treatment of AFB limb occlusion has been debated, but many recommended femorofemoral bypass (FFB). FFB grafts have had excellent patency rates. The durability of FFB specifically for AFB limb occlusion has not been reported. This study retrospectively examined a 10-year experience with FFB for AFB limb occlusion to determine FFB performance.

METHODS

Between 1982 and 1992, FFB was performed on occluded AFB limbs in 22 patients (14 men and 8 women). Reoperation was performed for disabling claudication in five cases, but the remaining 17 patients (77%) had critical limb ischemia. FFB originated from the contralateral patent AFB limb in all cases. Distal anastomosis was to the common femoral artery (n = 8) or the profunda femoris (n = 14). FFB graft patency was confirmed by direct Doppler arterial examination over a mean follow-up of 47 months.

RESULTS

The cumulative life-table primary patency rate of FFB was 54% at 5 years. Reoperative procedures performed in nine cases resulted in a secondary patency rate of 84% at 5 years. The limb salvage rate was also 84% at 5 years, reflecting the impact of successful reoperation. Major amputations (two below-knee, one above-knee) were necessary in only three cases. There were no perioperative deaths after FFB, and the cumulative 5-year survival rate was 77%.

CONCLUSION

Aortic graft limb occlusion occurs less frequently than failure of infrainguinal grafts making the success of specific reoperative strategies difficult to document reliably. This study suggests that FFB is a safe and durable alternative for AFB limb failure. An aggressive policy of reoperation has resulted in successful extension of FFB graft function and an excellent rate of limb salvage.

Tobacco use as a distal predictor of mortality among long-term narcotics addicts

BACKGROUND

This study examined patterns of tobacco and narcotics use, associated morbidity, and subsequent mortality among long-term narcotics addicts.

METHODS

The analysis included 405 patients selected from admissions to the California Civil Addict Program during 1962 through 1964. Measures were obtained at admission and at two face-to-face interviews conducted in 1974-1975 and 1985-1986 and included use of narcotics, tobacco, alcohol, and other substances, as well as morbidity and mortality information.

RESULTS

For the 405 addicts interviewed initially in 1974-1975, the average age was 36.7 years, the mean age at onset of smoking was 13.1 years, and first narcotics use occurred at 18.4 years. Ninety-eight percent reported experience with cigarette smoking, 84% were currently smoking, and 31% tested positive for opiates by urinalysis. In 1985-1986, at the second interview, among the 328 interviewed, 74% reported current smoking and 32% tested positive for opiates. Seventy-seven (19%) had died. Major proximal causes of death included drug overdose, violence, and alcohol-related conditions. The death rate of the smokers identified in 1974-1975 was four times that of nonsmokers. The only other distal variable that predicted mortality was disability status in 1974-1975.

CONCLUSIONS

Smoking status and disability history were major distal predictors of subsequent death. However, tobacco-attributable mortality was directly substantiated as a proximal cause of death by only 16% of the death certificates.

Aortic diameter as a function of age, gender, and body surface area

BACKGROUND

An aortic aneurysm is defined as a 50% or greater increase in diameter compared with normal levels or the level of the left renal vein. However, normal diameters for many aortic segments are not known, and the aortic segment at the left renal vein may be enlarged. The purpose of this study was to determine normal diameters of the thoracic and abdominal aortas in relationship to age, gender, and body size.

METHODS

Aortic diameters (ADs) were determined at four anatomic levels: thoracic aorta, abdominal aorta at the celiac axis, renal arteries, and midway between the renal arteries and the bifurcation. ADs were determined with the use of a video analyzer and an electronic caliper. Computed tomographic scans (n = 389) obtained for nonvascular diagnoses were analyzed according to gender, age, height, weight, and body surface area (BSA).

RESULTS

At all levels and in each decade the AD is significantly greater in men than in women (p < 0.0001). BSA is a better predictor of size than height or weight. AD increased with age at all levels, and there was a positive correlation between the AD and BSA and gender. Expected ADs for each aortic segment may be calculated according to regression equations. Age-, gender-, and BSA-matched patients with abdominal aortic aneurysms revealed significant enlargements in all proximal aortic segments.

CONCLUSIONS

AD at a given level is a function of gender, age, and BSA. When these variables are known, it is possible to calculate an expected AD. The AD is greater at all levels in patients with abdominal aortic aneurysms and in men compared with women.

Prevalence of walking impairment in young, healthy adults

64 students' mean walking distance was greater than that of a presurgical group studied by Regensteiner and colleagues. The students were also faster. Between the distance and speed measures, r = .08.

Rapid smoking of menthol and nonmenthol cigarettes by black and white smokers

White subjects took significantly more puffs of cigarette smoke before stopping than did black subjects in a modified, controlled-dose rapid smoking procedure. Paradoxically, however, no racial differences were detected for changes in carbon monoxide levels, or changes in cardiovascular variables (systolic and diastolic blood pressure, and heart rate). Due to the cooling and topical anesthetic properties of menthol, it was hypothesized that menthol and regular cigarette smokers would take more puffs from menthol cigarettes than from regular cigarettes before stopping in the controlled-dose rapid smoking procedure. However, no difference was observed for the number of puffs taken from regular as opposed to menthol cigarettes (cigarette type condition) and no differences were found for Cigarette Preference (regular smokers vs. menthol smokers).

Popliteal venous aneurysms

Popliteal venous aneurysms are rarely reported but represent a potentially life-threatening condition requiring accurate diagnosis and surgical resection. Newer techniques including magnetic resonance imaging, computed tomography, and color flow duplex imaging offer new noninvasive methods to define popliteal fossa venous abnormalities. Excision of the aneurysm with venous reconstruction removes the embolic source and maintains prograde venous flow. A posterior surgical approach to the popliteal fossa is recommended to facilitate exposure. Early control of venous outflow is needed to avoid thromboembolism. This report describes the diagnosis and treatment of popliteal venous aneurysms in three patients with a review of the English-language literature.

Carotid endarterectomy with an occluded contralateral carotid artery

Five hundred twenty-six patients who underwent carotid endarterectomy were separated by reviewing those 81 (15%) patients with an occluded contralateral carotid artery and those 445 (85%) with nonocclusion. The population characteristics and surgical indications were similar between the occluded and nonoccluded groups. Ipsilateral plus contralateral perioperative stroke occurred during 11 of 445 operations (2.5%) in which the contralateral carotid was patent, and during which no patient was hemorrhagic. Those patients with contralateral artery occlusion had ipsilateral plus contralateral stroke in 4 of 81 cases of (4.9%) (NS). Intracerebral hemorrhage was responsible for two of four strokes after carotid endarterectomy with contralateral occlusion (p = 0.001). Restenosis to greater than 50% by duplex scanning was more rapid in the occluded group with primary closure (no patch) (p = 0.025) and for men (p = 0.025). Although perioperative safety is comparable, patients with contralateral carotid occlusion may have a greater risk of intracranial hemorrhage and a more rapid rate of restenosis in some subgroups.

Upper extremity bypass grafting. A 15-year experience

OBJECTIVE

To analyze the perioperative morbidity and mortality, long-term patient survival, and patency characteristics of arterial bypass related to upper extremity ischemia.

DESIGN

This is a retrospective review of sequential patients undergoing upper extremity arterial bypass during a 15-year period at a single tertiary-care teaching hospital. Data are expressed in a 5-year life-table format and interpreted using log-rank analysis.

PATIENTS

Seventy-four patients with upper extremity ischemia undergoing arterial bypass, which included 95 separate operations.

MAIN OUTCOME MEASURES

Operative morbidity and mortality, life-table survival, life-table bypass graft patency, and limb salvage are reported.

RESULTS

There was no operative mortality, and there was a single major amputation. Survival rate was 86% at 5 years, and overall patency rate was 61.2% at 5 years, with autogenous conduits superior at all sites compared with prosthesis (70.9% vs 37.7%). Secondary operation was inferior to primary bypass (66% vs 48%) and associated with higher morbidity (22% vs 5%). All far distal forearm prosthetic bypass grafts failed within 1 year.

CONCLUSIONS

Primary upper extremity bypass with venous conduit is a safe, durable procedure, after which prolonged patient survival can be expected.

Descending thoracic aorta-to-femoral artery bypass: ten years' experience with a durable procedure

PURPOSE

Arterial bypass from the descending thoracic aorta to the femoral system provides successful perfusion when an approach to the abdominal aorta is undesirable. This review of a large series with a decade of experience was conducted to better define patency data and the natural history of patients after this operation.

METHODS

During a 10-year period, 21 patients, 18 men and 3 women (mean age 57 years), underwent descending thoracic aorta to left femoral artery bypass with femorofemoral bypass. These were placed to convert axillopopliteal or axillofemoral grafts (12 patients) to a more permanent inflow source. The axillary bypasses had been previously placed to allow removal of infected aortic grafts and had undergone a total of 14 revisions or thrombectomies before conversion. In addition, patients had this procedure after multiple failed attempts (at least two) at intraabdominal aortic repair (five patients) or to avoid exploration of the abdomen after extensive retroperitoneal dissection or radiation (four patients). Surgical technique involved a seventh interspace thoracotomy with a transdiaphragmatic retroperitoneal anterior axillary line tunnel to the left groin.

RESULTS

There was no perioperative mortality. The mean hospital visit was 15.1 days and intensive care stay 4.3 days. There was no perioperative myocardial infarction, stroke, or renal failure that necessitated dialysis. With a follow-up period of 1 to 121 months (mean 44), the 4-year patency rate was 100%. A single graft failed at 49 months but was renewed by thrombectomy and femorofemoral bypass. Thus the extended patency rate was 86%, but the secondary patency rate remained 100% throughout. Since the thoracic operations, patients have required five femoropopliteal, three femorotibial, two profunda, and two femorofemoral operations.

CONCLUSIONS

Descending thoracic aorta-to-femoral artery grafting is a safe, extremely durable arterial bypass configuration. It is an excellent reconstruction for survivors of aortic graft infection, those who have had multiple failures of aortic grafts, and patients for whom abdominal exploration would be hazardous.

Management of sudden profuse bleeding from varicose veins

Varicose vein bleeding of the lower extremities is an unusual but pressing indication for treatment and can be lethal. This series reviews operative and injection treatment of such veins in patients with bleeding. During a 49-month period 14 patients (eight men and six women) with a mean age of 62.1 years (range, 23 to 93 years) were seen after venous bleeding related to varicosities of the lower extremity. They described between one and five episodes of bleeding (mean, 2.4), but only one patient required transfusion. The site of bleeding was the lower calf or foot in 11 and affected the thigh in three patients. One was in the third trimester of pregnancy. Nine patients had lesions involving clustered small 1 mm or less diameter varicose veins, whereas five had large diffuse varicose vein formation. None had evidence of coagulopathy, and the inciting episode was either unknown or related to minor trauma. Treatment of eight patients with small-diameter veins was instituted with 0.2% sodium tetradecyl injection with a 30-gauge needle, thrombosing veins within 5 cm of the bleeding focus. A total of 13 ml solution (1.0 to 27 ml) per patient was used during two or three treatment periods (mean, 2.5 treatment periods) spaced 2 weeks apart. Six patients were treated by means of standard vein-stripping techniques or local branch removal at the bleeding site. Effective thrombosis was achieved in all eight patients with small (less than 1 mm) varicose veins treated with sclerosis. In five patients who underwent surgery there was effective resolution of the hemorrhage. One patient with small-diameter varicose veins clustered about the ankle underwent operative treatment and had venous stasis ulceration requiring compression dressings for healing. In all 14 cases control of bleeding was obtained, with follow-up to 49 months (mean, 21.3 months); one had rebleeding from a site 32 cm remote from the original injected area 11 months after treatment. Bleeding from small-diameter varicose veins of the lower extremity can be controlled effectively by sclerosing techniques with sodium tetradecyl. Larger veins are managed with operative removal. Combining these techniques provides efficient management of often-elderly patients, many in an outpatient setting.

Limb-threatening ischemia complicated by perigenicular infection

When graft infection or infection of the medial leg or popliteal fossa precludes a standard approach to revascularization of the ischemic leg, the literature suggests amputation may be the most prudent course because of excessive perioperative mortality and morbidity of attempts to reestablish axial flow. The purpose of this study is to define the outcome of revascularization when limb-threatening ischemia is complicated by perigenicular infection. Of 1020 infrainguinal reconstructions performed since 1984, nine (0.9%) presented with limb-threatening ischemia and graft or wound infections involving the popliteal fossa (6) or medial thigh or calf wounds (3) which precluded standard revascularization in the five women and four men. Risk factors for infection included diabetes mellitus (5/9), wound hematoma at initial operation (2/9), and intravenous drug abuse (1/9); Staphylococcus aureus was the predominant organism in all infected wounds and two popliteal fossa infections. The other deep infections grew group D streptococci, Enterococcus, and Salmonella. Extra-anatomic reconstruction was performed from the femoral (7) and iliac vessels (2) extending to the below-knee popliteal (2), the anterior tibial (4) and the peroneal (3) arteries using vein (5), and PTFE (4) in a lateral tunnel which avoiding the plane of the infection. Postoperative complications included MI (1), early graft thrombosis (2), and osteomyelitis of the femur (1); there were no deaths. With a mean follow-up of 19 months (3-57 months), primary graft patency was 66% and secondary patency was 78%, resulting in salvage of 66% of extremities at risk. These data demonstrate the safety and efficacy of extra-anatomic reconstruction for maintaining axial flow when limb-threatening ischemia is complicated by perigenicular infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Interleukin-1 beta and tumor necrosis factor-alpha release in normal and diseased human infrarenal aortas

The presence of chronic inflammatory cells in the adventitia and media of abdominal aortic aneurysms and aortic occlusive disease suggest an immunologic response. The purpose of this study is to determine whether normal or diseased infrarenal aortas liberate the inflammatory cytokines tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta). Twenty-six infrarenal aortic biopsies (5 aortic occlusive disease, 15 abdominal aortic aneurysms, and 6 cadaveric donors) were weighed, minced into small pieces, and incubated in media for 48 hours. Conditioned media was harvested at 48 hours and assayed for IL-1 beta or TNF-alpha with use of an ELISA assay. Comparison of groups was performed with a one-way analysis of variance. The constitutive IL-1 beta produced by abdominal aortic aneurysms was significantly different than that in cadaveric donors (908 +/- 194 pg/ml [SE] vs 100 +2- 30 pg/ml). There was no statistically significant difference between abdominal aortic aneurysms and aortic occlusive disease (908 +/- 194 pg/ml vs 604 +/- 256 pg/ml) or aortic occlusive disease and cadaveric donor (604 +/- 256 vs 100 +/- 30). In time-course studies for the release of IL-1 beta, abdominal aortic aneurysms demonstrated maximal release at 48 hours. IL-1 beta release was augmented by lipopolysaccharide in all categories. A dose response curve demonstrated maximal IL-1 beta release on stimulation with 5 micrograms/ml LPS. Constitutive TNF-alpha production was low, ranging from 13 +/- 1.5 pg/ml in cadaveric donor, to 20 pg/ml in aortic occlusive disease, and 24 +/- 11 pg/ml in abdominal aortic aneurysms. There was no augmentation in TNF-alpha with lipopolysaccharide.(ABSTRACT TRUNCATED AT 250 WORDS)

Axillary-popliteal artery bypass provides successful limb salvage after removal of infected aortofemoral grafts

Axillary-popliteal artery bypasses were placed to revascularize 28 extremities for 17 patients who were undergoing removal of infected aortofemoral grafts. Polytetrafluoroethylene (PTFE [polytef]) material was anastomosed to the above-knee popliteal artery in 22 cases and to the below-knee popliteal artery in six limbs. All but one patient had axillary-popliteal grafts in place before excision of the aortic graft. In 12 groins, vein-patch angioplasty was performed after removal of the infected aortic graft to provide retrograde pelvic perfusion and maintain femoral patency for future reconstruction. Three patients (18%) died of septic-related, multisystem organ failure. With a mean follow-up of 25 months, primary patency was 75% at 1 year and 43% at 2 years. Secondary patency, maintained by thrombectomy (n = 7), revision (n = 3), and conversion to warfarin sodium (Coumadin) therapy (n = 6) was 100% at 2 years, and limb salvage was achieved for all surviving patients.

Long-term evaluation of composite sequential bypass for limb-threatening ischemia

When sufficient vein for a completely autogenous femorotibial artery bypass is not available, composite sequential grafting by using vein combined with polytetrafluoroethylene material is a surgical option. This study reviews what is currently the largest collection of these grafts and focuses on technical aspects and long-term patency characteristics. During a 7-year period 67 composite sequential bypasses were used to manage rest pain (38), ulcer (18), or gangrene (11) in 62 patients (mean age, 66 years). Fifty-two percent were men, and 51% had diabetes. This method was used as a primary reconstruction in 30, a second bypass in 16, and in 21 it was used after multiple other failed bypasses. Femoral to above-knee popliteal (44) and below-knee popliteal (23) 6 mm polytetrafluoroethylene grafts were placed. Then extensions of greater saphenous (57) or lesser saphenous (10) vein were anastomosed to the anterior tibial (19), posterior tibial (26), or peroneal (22) arteries. Fifty-three percent were maintained on long-term warfarin (Coumadin) anticoagulation, and 33% were maintained on aspirin. No deaths occurred in the perioperative period. Bypass patency was ascertained by a Doppler pressure and waveform analysis, with mean follow-up of patency or to the time of graft failure of 33 months (1 to 91 months). Three-year patient survival was 72%. Cumulative life-table primary patency of 72% (1-year), 64% (2-year), and 48% (3-year) was calculated. Two grafts are functioning 7 years after placement. Limb salvage was 84% at 2 years and 70% at 4 years. At the time of failure, five grafts retained a patent venous bypass segment, which allowed prompt reconstruction of the proximal portion. In a comparison of grafts with early failure and those with long-term patency, the SVS/ISCVS runoff score, vein diameter, tibial artery diameter, and coagulation status were similar. However, patients with the popliteal anastomosis above the knee had 2-year patency of 72% compared with 46% for those with below-knee anastomoses. This technique, when possible, appears preferable to an all prosthetic tibial bypass.

Assessment of adherence to a low-fat diet for breast cancer prevention

BACKGROUND

The relationships between self-reported adherence to a low-fat diet in healthy women between the ages of 44 and 69 and a number of correlates of this self-reported behavior were examined in an attempt to improve monitoring of adherence to nutritional intervention trials for breast cancer prevention.

METHODS

Dietary fat intake in 87 women who completed 6 months of nutritional intervention was reduced from 38.2 +/- 5.9% to 21.7 +/- 7.8% of total energy intake (P less than 0.005). Reported total calorie intake was reduced by approximately 20%.

RESULTS

Body weight decreased by 2.7% from 68.1 +/- 11.2 kg to 66.3 +/- 11.9 kg (P less than 0.05). Fasting total plasma cholesterol levels decreased from 205 +/- 31 mg/dl to 184 +/- 29 mg/dl (P less than 0.05). Fasting plasma triglyceride levels did not change significantly (97 +/- 44 mg/dl vs 101 +/- 55 mg/dl). Relative percentage changes in body weight correlated with percentage changes in dietary fat intake (r = 0.23, P less than 0.05).

CONCLUSION

Self-reported changes in dietary behavior correlated significantly with objective changes in body weight and fasting cholesterol in these healthy women encouraged to consume a low-fat diet for prevention of breast cancer.

Aneurysm or occlusive disease--factors determining the clinical course of atherosclerosis of the infrarenal aorta

Atherosclerosis of the infrarenal aorta results in distinct clinical entities--aortoiliac occlusive disease (AOD) and abdominal aortic aneurysm (AAA). Although loss of collagen has been implicated in AAA, collagen accumulation plays a role in AOD. In vivo collagen-gene expression can be assessed using complementary DNA for collagen types I and III alpha-chains. The purpose of this study is to compare total collagen (type I + III) and collagen types I and III messenger RNA in AAA, AOD and normal aorta. Specimens were collected from the infrarenal aorta during operation for AOD (n = 7), AAA (n = 7), autopsy, or organ procurement (normal; n = 7). Northern transfer analysis of total RNA was used to compare mRNA levels for type I and III collagen. After preliminary extraction, specimens were hydrolyzed for hydroxyproline analysis used to calculate total collagen (type I + III). Relative levels of type I (pro-a1[1]) mRNA were greater in both AOD (0.77 +/- 0.35) and AAA tissue (0.94 +/- 0.24; p = 0.6) than in normal aorta (0.02 +/- 0.03). Type III (pro-a1[III]) mRNA levels were also greater in AOD (2.52 +/- 0.19; p = 0.09) and AAA tissue (3.15 +/- 1.3) than in normals (0.97 +/- 0.47). Total collagen concentration was increased in AOD (45.6% +/- 3.1% dry weight; p less than 0.05) but not AAA tissue (27.8% +/- 4%) when compared to normal aorta (34.7% +/- 2.3%). Collagen type I and III gene expression is greater in older, diseased aorta, yet collagen accumulated only in AOD. This implies a similar synthetic response in both AOD and AAA. Thus, proteolytic degradation in AAA appears to determine collagen content and possibly the clinical course of the atherosclerotic process.

Excimer laser-assisted femoral angioplasty: early results

The ability to ablate atheroma without generating heat makes the excimer laser wavelength a promising intraluminal technique for the treatment of arterial occlusive disease. This series reviews a preliminary experience treating patients with superficial femoral arterial disease admitted with limb-threatening ischemia or claudication. Twenty-six diseased superficial femoral arteries (5 stenotic and 21 occluded) were treated in 23 consecutive patients. Patients with claudication (18) reluctant to undergo bypass or with limb-threatening ischemia (8) at extremely high risk for surgery were included. There were 10 men and 13 women with a mean age of 67 years. A 308 nm excimer laser with an over-the-wire catheter (19) or balloon-centered end-on catheter (7) was used followed by balloon angioplasty. Twenty-four procedures were performed percutaneously, and two were performed with the vessel open in the operating room. Technical success, defined as disobliteration confirmed by angiography and greater than 0.15 increase of the ankle/brachial index, was achieved in 15 of 26. Eleven of 21 occlusions (52%) and four of five stenoses (80%) were opened. Only two of 11 lesions longer than 10 cm were successfully treated. Unsuccessful attempts (technical failure) occurred in 11 of 26 patients and resulted in four elective and one emergency femoral-popliteal bypass. Five patients were discharged with their claudication unchanged, and one had an elective amputation. Six arterial perforations with three arteriovenous fistulas occurred, all resolved without operation. No unanticipated limb loss occurred. In the 15 successful cases, the mean ankle/brachial index increase was 0.34. Seven (47%) of these 15 remain patent with a mean follow-up of 9.5 months (1.5 to 14 months).(ABSTRACT TRUNCATED AT 250 WORDS)

New uses of the laser in thoracic and cardiovascular surgery

Lasers have been accepted in general thoracic surgery as resectional tools which allow precise hemostasis and maximal salvage of normal lung tissue. Used endoscopically, with or without associated photodynamic therapy, we have provided acceptable palliation in some patients with obstructing tumors of the tracheobronchial tree and esophagus. Cardiovascular uses of the laser have been under extensive investigation at our medical center for many years. We have demonstrated that laser-assisted anastomosis of small vessels is possible, that early tensile strength and patency are excellent, but that long-term aneurysm formation is excessive. In addition, CO2 laser injury of the arterial intima leads to a marked increase in atheromata formation in animal models of atherosclerosis; this may be eliminated with the excimer laser. We have begun using the excimer laser to open obstructed peripheral and coronary arteries. New technology is emerging which allows dual fiber catheters which allow identification of tissue in an artery, ie calcium, atheromata, clot, media, etc. and instantaneous computer sensing/integration which initiates "fire" or "no fire" signals in the enclosed laser system, thus decreasing the chance of vessel perforation. These technologies, in association with balloon angioplasty, intravascular stents, and atherectomy devices are offering exciting alternate therapy for patients with obstructing atherosclerosis.

Arterial abnormalities of the shoulder in athletes

Vascular lesions of the shoulder may be misinterpreted as one of the more familiar shoulder abnormalities by a treating physician. We are reporting on 13 athletes who were found to have symptoms related to compression of the subclavian or axillary artery or their tributaries. Nine were amateur or professional baseball pitchers. Severe arm fatigue or finger ischemia, secondary to embolization, were presenting symptoms. Arm fatigue was noted in all pitchers. After complete history and physical examination, including auscultation for bruits in functional positions, all athletes were evaluated by noninvasive tests (Doppler and Duplex scanning). Arteriography was performed with positional testing, recreating overhead activity, and complete radiographic visualization of the dye to the digital arteries. Two patients were found to have subclavian artery aneurysm. The remaining athletes were found to have compression of the subclavian artery beneath the anterior scalene muscle (five patients), the axillary artery beneath the pectoralis minor (two patients), both arterial segments (two patients), and one was found to have arterial compromise at the level of the humeral head. Branch artery compression was also noted. One pitcher occluded the posterior circumflex humeral artery with embolization to the digit. The two patients with subclavian aneurysms underwent saphenous vein bypass with cervical rib resection. All of the other athletes except one underwent resection of a 2 to 3 cm segment of the anterior scalene muscle or pectoralis minor muscles. All returned to their previous level of activity except one patient who developed impingement type symptoms and required acromioplasty. He is currently undergoing rehabilitation. Proper recognition of vascular compromise in the upper extremity of athletes is essential to avoid the catastropic complications of arterial thrombosis.

Arterial abnormalities of the hand in athletes

Vascular lesions of the hand may be seen in athletes exposed to repetitive blunt trauma. Thirteen athletes seen from 1983 to 1988 experienced symptoms related to hand ischemia. Nine were professional baseball catchers. The majority of patients complained of chronic symptoms, including cold hypersensitivity (four patients), finger numbness (one), finger coolness (three), and finger blanching (three). Two patients had acute symptoms with sudden posttraumatic hand ischemia with finger and palmar pain. Diagnosis was established by history and physical examination and confirmed by noninvasive testing. Testing included use of Doppler examination and cold tolerance examination with thermistors. Two athletes required angiographic evaluation because of severe ischemia and continuous pain. All patients in this group were managed nonoperatively. Those with chronic complaints were counseled regarding cold avoidance and instructed to increase their glove padding. The two patients with acute symptoms required vasodilator (papaverine chloride) infusion, followed by intravenous heparin and dextran. All baseball catchers returned to their sport with dissipation of symptoms.

A comparative study of intraoperative angioscopy and completion arteriography following femorodistal bypass

A prospective comparison of the findings on standard completion arteriography with those seen using videoangioscopy was done following 49 cases of "femorodistal" bypass grafting in 47 patients. The two techniques were compared with respect to the detection of technical defects, modification of the surgical procedures, early graft patency (72 hours), and complications. Completion arteriography was specific (95%) but only moderately sensitive (67%) compared with angioscopy for detection of technical problems. Following angioscopy, significant alterations in the surgical procedure were noted in 5 (10%) of the 49 cases. Early graft failure occurred in 3 (6.1%) cases but none were identifiably due to technical problems. Four patients suffered postoperative myocardial infarctions, 2 (4.2%) of which were fatal; no patients had contrast-induced allergies or renal failure. Angioscopy was measurably more accurate for the detection of technical problems than completion arteriography, but offered little information about distal arterial anatomy that may have an impact on graft patency or the use of antithrombotic therapy.

Distal embolization as a presenting symptom of aortic aneurysms

The records of 302 patients who underwent abdominal aortic aneurysm (AAA) repair between 1985 and 1990 were reviewed. Two hundred and forty-eight patients (82%) were asymptomatic, while 32 patients (11%) had ruptured aneurysms. During this period, 15 patients (5%) presented with distal embolization as the first manifestation of their AAA. The preoperative embolic event resulted in limb-threatening ischemia in 3 patients, digital ischemia in 11, and calf myonecrosis in 1. CT scan was performed in 14 of 15 patients demonstrating irregular, heterogeneous thrombus within the AAA. Only two of the AAAs were larger than 5 cm. Angiography demonstrated occlusive lesions but was not diagnostic for AAA in seven patients and resulted in three episodes of embolization. AAA was repaired with a tube graft in 4 patients while a bifurcated graft was required in 11 patients for aneurysmal (in 4 patients) and occlusive disease (in 7 patients) of the iliac arteries. All cases employed a transperitoneal approach, systemic heparin, and distal occlusion prior to aortic clamping. Complications included three major (below-knee) and five minor amputations, developing or worsening renal failure in five patients (33%), and death in two (13%). In comparison, mortality was 5% for elective repair and 66% for rupture during this same period. CT scan was safer and more informative than angiography. The morbidity of patients with AAA presenting with emboli is comparable with rupture. The risk of embolization does not correlate with size and indicates the potentially dangerous nature of small AAAs.

Computed tomography for evaluation of arterial disease in the popliteal fossa

The clinical details, arteriograms, and computerized tomographic (CT) scans of 28 patients with popliteal arteriopathies were reviewed retrospectively to determine the usefulness of CT for the diagnosis and treatment of these disorders. Arteriography diagnosed 70% and CT diagnosed 98% of the 45 popliteal disorders. Popliteal aneurysms were not detected by arteriography because of occlusion in seven (20%) patients and intraaneurysmal thrombus that produced no luminal compromise in two. Thrombus was identified by CT in 22 of 24 patient aneurysms and suspected as the source of digital embolization in 7. Graft aneurysms were identified by CT in two cases, but one was not detected by arteriography because of graft occlusion. Two mycotic aneurysms were identified, one by arteriography and not by CT because of misinterpretation of a periarterial hematoma. Popliteal entrapment was diagnosed by CT in three cases, and in two cases occlusion precluded diagnosis of entrapment by arteriography. Adventitial cystic disease was diagnosed accurately by CT in three cases, and in two there were no characteristic arteriographic abnormalities. In cases of entrapment and cystic disease, the CT findings allow the surgeon to plan his approach through a posterior incision, which in these two instances facilitates surgical technique. CT provides detail of the arterial wall, intraarterial contents, and surrounding musculoskeletal anatomy, all of which are useful for accurate evaluation of arterial disorders of the popliteal fossa.

Narcotics Addicts: Effect of Family and Parental Risk Factors on Timing of Emancipation, Drug Use Onset, Pre-Addiction Incarcerations and Educational Achievement

The family background characteristics of 756 male heroin users were examined to determine the effects of selected family risk factors on the timing of onset of emancipation and drug use, on pre-addiction incarcerations and on educational attainment. These risk factors included family size, birth order, socioeconomic status, family drug use, parental history of alcoholism, parental absence, and family history of incarceration. The two measures of age of emancipation were age on leaving school and age on leaving home. Age of onset of regular use was measured for the following drugs: tobacco, alcohol, marijuana and heroin. Incarceration measures included the occurrence of juvenile detention and the time spent in prison prior to first addiction. Educational attainment was a score on a California State achievement test. Larger family size, higher birth order, parental alcoholism and parental absence were found to have a cumulatively negative effect on how young the respondents were when they first left home and when they first used particular drugs regularly, on their level of tested academic achievement, and on their probability of juvenile detention. Implications for social policies designed to prevent drug abuse are discussed.

Collagen types and matrix protein content in human abdominal aortic aneurysms

Deficiencies of total collagen, type III collagen, and elastin have been proposed to explain aneurysm formation. Infrarenal aortas were collected from 19 patients (age 70 +/- 7 years) undergoing operative repair of abdominal aortic aneurysms (diameter 7 +/- 2 cm) and from 13 autopsies (age 63 +/- 17 years) of patients without aneurysm disease (controls). Wall thickness and collagen and elastin concentration were determined in full-thickness aorta. Collagen types I and III were measured after digestion with cyanogen bromide, which solubilized nearly 90% of total collagen for typing. Cyanogen bromide peptides were separated by sequential carboxymethylcellulose and agarose chromatography and quantified by peak area measurement with computerized image analysis. Histologic examination revealed prominent inflammatory cell infiltration and deficient, fragmented elastin in the aneurysms. Aortic wall thickness was similar in aneurysms and in control specimens. In the aneurysms, collagen was increased (37% +/- 16% vs 24% +/- 5%; p less than 0.05) and elastin was decreased (1% +/- 1% vs 12% +/- 7%; p less than 0.001), expressed as a percentage of delipidized, decalcified dry weight. Collagen type I accounted for 74% +/- 4% of aneurysm and 73% +/- 4% of control collagen solubilized for typing, and collagen type III accounted for 26% +/- 4% of aneurysm and 27% +/- 4% of control collagen solubilized for typing. Neither patients with a family history of aneurysms nor those without a history of aneurysms had collagen type III deficiency. Atherosclerotic abdominal aortic aneurysms are associated with an inflammatory process and may result from elastin degradation and not a deficiency of type III collagen.

Weight reduction for breast cancer prevention by restriction of dietary fat and calories: rationale, mechanisms and interventions

A large body of epidemiologic evidence and data drawn from animal feeding studies have led to the feasibility testing of clinical breast cancer prevention trials based on the restriction of dietary fat intake. The animal data strongly suggest that restricting calories as well as fat inhibits breast cancer promotion. Body fat correlates with dietary fat intake in human populations. Obese postmenopausal women have increased levels of circulating bioavailable estrogen capable of promoting breast cancer growth. We propose that restriction of dietary fat intake will decrease total calorie intake and result in a loss of body fat in postmenopausal women. This loss of fat will decrease estrogen production from adrenal androgens and increase bioavailable estrogen, leading to decreased promotion of estrogen-dependent breast tumors. Intervention programs targeted at weight reduction via restriction of calories, reduction of dietary fat and increased physical activity are logical, practical and measurable strategies for reducing the risk of breast cancer in women at moderate to increased risk. Failure to account for variations in adherence to a restricted-fat diet in past feasibility studies has cast doubt on the hypothesis that restricting dietary fat intake can be utilized to reduce the risk of breast cancer. Current studies examining nutritional, hormonal and physiologic data in conjunction with evidence of adherence to dietary and lifestyle change will likely clarify the hormonal and physiologic effects of this potential nutritional strategy for breast cancer prevention.

Upper extremity arterial injury in athletes

Between 1983 and 1986, 23 athletes were evaluated for arm and hand complaints. Eleven players had symptoms of thoracic outlet compression. Severe arm fatigue (eight patients) and finger ischemia (three patients) were the presenting symptoms. In the remaining 12 athletes, symptoms of hand ischemia were predominant. Noninvasive testing with Doppler ultrasonography and duplex scanning (positional testing and finger systolic pressure recording) and cold immersion were used to aid in diagnosis. In the 11 athletes with thoracic outlet compression, arteriography confirmed the finding with compression of the subclavian artery in five, the axillary artery in one, both subclavian and axillary arteries in two, posterior humeral circumflex artery in one, and subclavian aneurysm in two. Compression of the suprascapular artery was identified in four, the subscapular artery in two, and the posterior humeral circumflex artery in one. Thrombosis of a first baseman's ulnar artery and occlusion of the palmar arch in a frisbee player were documented by arteriography. Decompression of the thoracic outlet consisted of anterior scalenectomy in five, pectoralis minor muscle division in one, and resection of both muscles in two. Removal of cervical rib with interposed vein graft was performed in the two players with arterial aneurysm. Hand ischemia in the remaining athletes was treated conservatively with Dextran-heparin infusion for acute ischemia. Repeat noninvasive study of all players demonstrated absence of compression in their playing position, and all have resumed their playing careers. Hand ischemia in athletes can be evaluated noninvasively and treated conservatively. Resection of hypertrophied muscles to decompress the thoracic outlet together with release of branch artery compression in selected athletes promotes perfusion to arm and shoulder muscles and helps to avoid the catastrophic complication of repetitive trauma leading to sudden arterial thrombosis.

The demise of primary profundaplasty

Although the importance of the profunda femoris artery in maintenance of lower extremity integrity was recognized in the earliest days of modern vascular surgery, disappointment with the performance of primary profundaplasty has emerged fully only in recent years. During the 10 year period from 1977 to 1987, only 17 patients were subjected to this procedure at Northwestern Memorial Hospital. The nine men and eight women averaged 65.6 years in age and exhibited the usual precursors of arterial insufficiency: a history of smoking in 12 patients (71 percent), clinical coronary artery disease in 8 patients (47 percent), hypertension in 7 patients, diabetes mellitus in 6 patients, hyperlipidemia in 2 patients, and uremia in 1 patient. Four patients exhibited hemodynamic improvement after profundaplasty (ankle-brachial index increase of greater than 0.15). Four required amputation postoperatively, and a fifth exhibited hemodynamic failure 9 months postoperatively and required amputation. Two patients required subsequent femoral-to-peroneal bypass to improve distal arterial perfusion. One patient died after the procedure, for a 5.9 percent mortality rate. Thus, the fact that profundaplasty has proved disappointing in the treatment of severe arterial insufficiency deserves emphasis at this time.

Multiple aneurysms in Behçet's disease

Behçet's disease is characterized by recurrent ulcers of the mouth and genitalia and relapsing iritis. It is now recognized as a chronic multisystem disease affecting the skin, mucous membranes, eye, joints, central nervous system, and blood vessels. One of the known vascular complications of Behçet's disease is aneurysm formation or venous thrombosis. The two patients with Behçet's disease in this report developed multiple aneurysms over a short time span. Vascular surgeons dealing with young adults with peripheral aneurysms must be aware of this uncommon yet challenging clinical entity.

The effect of distal arterial anatomy on the success of popliteal aneurysm repair

The success of bypass grafting for popliteal aneurysms may be compromised by the natural history of these lesions. During a 9-year period 35 patients had repair of 48 popliteal aneurysms. Elective repair was performed in 26 limbs and the remaining 22 limbs required urgent or emergent treatment after aneurysm thrombosis (16) or embolic digital ischemia (six). Retrospective review of preoperative and intraoperative arteriograms and CT or ultrasound scans was done to define the relationship of distal runoff anatomy to initial symptoms and long-term grafting success during a mean follow-up of 48 months. Only five of 48 limbs (10%) had three continuous tibial vessels and a patent pedal arch. Twenty-six limbs (55%) had one or no named calf vessels and 11 limbs had incomplete pedal arches. When thrombosis or symptomatic embolism occurred, the anatomy was significantly worse; 15 of 22 such limbs (68%) had one or no patent tibial vessels and seven had incomplete pedal arches. Nineteen of 28 aneurysms examined by CT or ultrasound scanning showed intraluminal thrombus. Eight of 13 patent aneurysms with intraluminal thrombus had one or no patent tibial vessels. The 5-year graft patency rate was 74% for the entire study group. Bypass for repair of asymptomatic aneurysms had a patency rate of 91% at 5 years vs 54% for symptomatic patients (p less than 0.05). Patients with popliteal aneurysms often have advanced tibial disease that appears worse in those with symptoms. The occurrence of a patent popliteal aneurysm with intraluminal thrombus and advanced runoff disease suggests that chronic microembolism may be an etiologic factor in the tibial disease observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Improved long-term patency of infragenicular polytetrafluoroethylene grafts

This article reviews late graft patency and the incidence of postoperative complications in 75 infragenicular polytetrafluoroethylene bypass grafts (20 posterior tibial, 26 anterior tibial, and 29 peroneal). All patients received a heparin infusion after operation and were switched to warfarin before discharge to maintain coagulation parameters (prothrombin time and partial thromboplastin time) approximately twice that of control subjects. Primary procedures were done in 14 patients (19%), and the remaining patients had one or more previous procedures. Ninety-seven percent of patients had limb-threatening ischemia. Graft patency was confirmed by interval examinations and Doppler ankle pressure measurements. The mean follow-up was 36 months, and long-term graft patency (4 years) was determined by life-table analysis. The 2-year cumulative patency rate for this group was 45% and the 4-year patency rate was 37%. The latter is significantly better than the patency rates of 12% reported for similar untreated randomized grafts. Anticoagulation was subtherapeutic in 15 patients at the time of graft thrombosis, and if these were excluded, the 2- and 4-year patency rates were 58% and 50%, respectively. Hematomas requiring drainage occurred in 10 patients (13.3%) and six patients (8%) developed wound infections, but graft infection occurred in only two patients. Two patients (2.6%) developed late bleeding complications necessitating cessation of the warfarin. There was one fatal perioperative myocardial infarction (1.3%) and four late deaths, none of which were related to the warfarin therapy. Although the incidence of postoperative hematoma and wound infection was increased, late complications occurred infrequently.(ABSTRACT TRUNCATED AT 250 WORDS)

Firewalking

Firewalking is known throughout recorded history and around the world. Ordinarily it is associated with religious beliefs or mystical states of mind in which the gods or unusual mental powers provide extraordinary protection for true believers or those with proper training. However, firewalking commonly involves hot materials of low heat capacity and poor thermal conductivity and sometimes the use of insulation. The excited or trance-like states of firewalkers contribute to the firewalkers' subjective experience but are not required for a successful walk. We conclude that elementary knowledge of physics and psychology is sufficient to explain the known observations of firewalking.

Workplace smoking policies: attitudes of union members in a high-risk industry

We surveyed members of a medium-size national union representing workers in high-risk industries to assess workers' support for union and company programs to help smokers break the habit and policies that restrict smoking. Two surveys were conducted that involved 690 respondents in 1984 and 593 respondents in 1985. Respondents overwhelmingly (82%) favored restrictions on smoking in the workplace but less than half agreed that companies or unions should be concerned about workers smoking off the job. For both smokers and nonsmokers, beliefs that cancer has specific causes and can be prevented strongly predict support for workplace smoking control policies. Exposure to company occupational health training also influenced smokers and nonsmokers to support selected smoking control policies. These and other findings led to the conclusion that: (1) educating workers about cancer may promote support for smoking control policies, and (2) smoking control policies are more acceptable in the context of a strong company health and safety program.

Patency of laser-assisted anastomoses in small vessels: one-year follow-up

Laser-assisted arterial anastomoses can now be performed with satisfactory short-term patency. This study was undertaken to evaluate patency and aneurysm formation with a 1-year follow-up. A microscopically guided CO2 laser was used to anastomose 1.5 to 2.0 mm carotid arteries in 24 rabbits. Under X6 to X40 magnification, 60 to 70 mW were delivered with a spot size of approximately 0.32 mm. One carotid artery underwent laser anastomosis; the opposite served as a sutured control (10-0 nylon sutures). The 48 end-to-end anastomoses were evaluated for patency and aneurysm formation at 3, 6, and 12 months. Aneurysms were defined as a 1.5 times increase in diameter at the anastomotic site. The vessels underwent microscopic examination. All laser-assisted and sutured anastomoses were patent up to 1 year. At 3 months, one of eight sutured and one of eight laser anastomoses were aneurysmal; stenosis was noted in one laser anastomosis. At 6 months, one of eight laser and 0 of eight sutured anastomoses were aneurysmal. At 12 months, one of eight rabbits had died; of the remaining seven, three of seven laser and zero of seven sutured anastomoses were aneurysmal. In total, five of 23 (21.7%) aneurysms developed with the laser technique and one of 23 (4.3%) with the suture technique (p less than 0.05). Laser-assisted anastomoses are technically feasible, and patency at 1 year is equal to those performed with the suture technique. Aneurysm formation is a consistent problem that demands further investigation.

Arterial aneurysm model using laser energy

Continuous wavelength laser energy can be used to perform arterial anastomoses, but all experimental series report an incidence of anastomotic aneurysm formation. To elucidate the mechanism of aneurysm production, controlled injuries of the arterial wall were created with a pulsed CO2 laser beam (40-50 mW). One carotid and one femoral artery of 10 New Zealand rabbits were injured with laser and the contralateral vessel was exposed surgically as a sham operation. At reoperation 8 to 11 weeks later, all 40 arteries were patent. None of the carotid shams, one carotid laser, two femoral shams, and eight femoral laser vessels (80%) were aneurysmal. Histologic examination revealed extensive medial necrosis with fragmentation of the internal elastic lamina in the area of these aneurysms. Femoral vessels were significantly smaller than carotids (P less than 0.001) and the high incidence of aneurysm formation in the former may be due to the relatively greater area of injury. This new model of aneurysm formation after laser injury suggests a need for further study prior to clinical application of this technology, especially in vessels smaller than 2 mm in diameter.

Technical defects as a cause of early graft failure after femorodistal bypass

Technical defects threaten the early patency of infrainguinal bypass grafts. We reviewed 849 cases of femorodistal bypass to determine the incidence of technical graft failure, as well as other causes of early graft occlusion. The efficacy of adjunctive intraoperative arteriography was assessed. Early graft failure occurred in 62 (7.3%) cases and was due to technical defects in nine (14.5%) cases. Embolization caused early failure in six (9.7%) cases, coagulation disorders caused occlusion in ten (16.1%) cases, and failure was due to inadequate runoff in seven (11.3%) cases. No identifiable cause of graft thrombosis was found in 30 (48%) cases, but thrombectomy and empiric anticoagulation therapy salvaged 25 of these grafts. Intraoperative arteriography was very specific (98%) and moderately sensitive (76%) for the detection of technical defects in this series. Technical defects appear not to be the most common cause of early infrainguinal bypass graft failure and were found in only 1% of all cases reviewed. Critical attention must be given to other causes, such as emboli, and particularly to disorders of the host coagulation system that may threaten the success of the procedure.

Blockade of contralateral carotid sinus nerve enhances ipsilateral nerve action potentials under halothane anaesthesia

In 10 dogs, one carotid sinus was isolated from the systemic circulation without disturbing its sympathetic innervation. The isolated sinus was connected to a servo-controlled pressure generator which kept mean intrasinus pressure, pulse pressure, and frequency of pulsation constant. The carotid sinus baroreceptor nerve action potentials (NAP) were measured, together with the intransinus and systemic pressures. Following control measurements, the end-tidal concentrations of halothane in oxygen were varied between 0.0 and 2%, in random increments of 0.5%, each with 30 min of stabilization. The carotid sinus NAP response to halothane was biphasic in a dose-dependent manner. The series was repeated after neural blockade of the contralateral sinus with 1% lignocaine 2-3 ml. This blockade enhanced all NAP responses (P less than 0.001), suggesting that a central inhibitory effect, initiated by the contralateral sinus, had been removed.

The reoperative potential of infrainguinal bypass: long-term limb and patient survival

The present study reviews the fate of patients undergoing reoperation after failure of infrainguinal bypass grafts. During a 10-year period, 202 patients with failed distal bypass grafts had 389 infrainguinal reoperative procedures, an average of 1.9 reoperations per patient. Including the initial procedure and subsequent reoperations, a total of 591 operations were performed in this group. Secondary bypass was performed in 101 patients, a tertiary procedure in 51, a fourth bypass in 30, and more than four operations were required in 20 patients. Reoperation was performed to treat severe ischemia (rest pain, ulceration, or gangrene) in 377 of 389 cases (97%). Repetitive bypass was performed with autogenous vein in 21 cases (7.4%), composite grafts in 16 patients (5.6%), and polytetrafluoroethylene in 247 cases (87%). The remaining 105 reoperations were thrombectomy in 77 cases, thrombectomy plus distal angioplasty in 20 cases, and profundaplasty in eight cases. The distal anastomosis was to the popliteal artery in 14% of reoperative cases and to the tibial or peroneal artery in 59%. Mean follow-up for all patients was 70 months. Four operative deaths occurred in 389 reoperations (1.0%), and there were 35 late deaths. The cumulative life-table 5-year survival rate for all patients was 80%. The operative morbidity rate was 12.3%, including wound infection in 3.1% and hematoma in 6.4%. Sixty-seven cases required major amputation, below-knee in 48 (72%) and above-knee in 19 (28%). The 5-year limb salvage rate was 59%. Cumulative graft patency was 37% at 5 years. The 80% 5-year survival rate may reflect aggressive management of associated carotid and coronary artery disease. The demonstrated long survival indicates that recurrent ischemia after distal bypass failure requires attention. In this study, re-operation provided long-term limb salvage in most cases without significant compromise in patient safety or amputation level if amputation was required.