Mortality studies of machining fluid exposure in the automobile industry. V: A case-control study of pancreatic cancer.

Results are presented from a case-control study of 97 cases of pancreatic cancer nested in a cohort of workers from three automobile manufacturing plants. Risk was examined for lifetime exposure to straight, soluble, and synthetic metalworking fluids, as used in specific machining or grinding operations, as well as for constituents of the fluids. Pancreatic cancer was associated with exposure to synthetic fluids in grinding operations, with an odds ratio of 3.0 (95% CI: 1.2-7.5) among those with more than 1.4 mg/m3-years of exposure. We were unable to examine synthetic exposure in the absence of grinding because there was virtually no exposure to synthetics in machining operations in this study population. Although a disproportionately high percent of the cases were black, no black workers had any exposure to synthetic fluids, and no other measured exposure was found to be related to risk. Thus, the previously documented excess risk of pancreatic cancer among blacks in this cohort remains unexplained.

Cerebrovascular magnetic resonance angiography: a critical verification.

Because simultaneous noninvasive noncontrast imaging of cervical and cerebral vasculature and brain is possible with magnetic resonance angiography (MRA) and imaging (MRI), the following study was undertaken from July 1990 to January 1992. One hundred twenty-eight patients were examined with General Electric 1.5 Tesla MRI systems. Axially acquired volumetric three-dimensional time-of-flight MRA with 0.7 mm3 voxel size with regional maximum intensity projection after processing followed a two-dimensional time-of-flight localizing sequence. These two MRA sequences combined with spin-echo parenchymal brain MRI were compared with duplex scans, contrast angiograms, and surgical findings. Blinded readings by a radiologist and vascular surgeon allowed comparison of grades of luminal diameter narrowing (normal, mild, moderate, severe, and occluded) seen on MRA to be compared with those of Doppler and contrast angiography. Excluding 12 nondiagnostically imaged internal carotid arteries (10 MRA) and limiting duplex correlation to within 5 days of the MRA examination allowed critical appraisal of 182 internal carotid arteries. Exact correlation of grade of stenosis was obtained by the radiologist in 136 (74.7%) of 182 arteries and the surgeon in 138 (75.8%) of 182 arteries. Spearman rank correlation analysis found rank correlation coefficients of 0.88 (p < 0.001) and 0.83 (p < 0.001), respectively, for the radiologist and vascular surgeon. Disagreement one category apart was found by the radiologist in 35 studies (19.3%) and the surgeon in 28 studies (15.4%). Two or more grades of disagreement were found by the radiologist in 11 studies (6%) and the surgeon in 16 studies (8.8%). Contrast angiogram-MRA agreement was found in 86% of 36 internal carotid arteries. The degree of stenosis detected by MRA was concordant with surgical findings in 39 of 40 patients. Thus MRA emerges as a useful and accurate method of obtaining cerebrovascular evaluation in clinical practice.

Inferior vena cava bypass: experimental evaluation of externally supported grafts and initial clinical application.

Inferior vena caval obstruction is an unusual but important clinical problem for which adequate treatment previously has not been available. Recently, a polytetrafluoroethylene (PTFE) graft with external rigid spiral supports was developed that appeared particularly applicable to the venous system. In 18 dogs a 15 cm length of Impraflex was placed from the proximal right common iliac vein to the inferior vena cava (IVC) at the level of the renal veins after IVC and right iliac vein interruption. End-to-end and end-to-side iliac vein anastomoses were alternated, with and without distal femoral arteriovenous (AV) fistulas (AVFs). At 2 months, with a distal AV fistula, 11 of 12 (92%) grafts were patent, angiograms demonstrated no evidence of intraluminal clot, and there was no hind limb edema. Following AVF ligation 2 months after graft insertion, 10 grafts remained patent, but five developed some intraluminal thrombus and one of them progressed to complete occlusion. Four months after fistula ligation (6 months after graft insertion) 9 of 12 grafts (75%) remained patent. All six grafts without distal AVF were occluded within 1 week. This procedure was performed on one severely symptomatic patient who had IVC occlusion, and currently the patient shows marked improvement. Thus IVC bypass is possible when an externally supported PTFE prosthesis is complemented by a temporary AVF.

Selective streptokinase infusion: clinical and laboratory correlates.

Selective intra-arterial infusions of streptokinase (SK) were made in 50 arteries of 45 patients with a variety of acute thromboembolic conditions. The most common regimen was 5,000 units of SK/hour for 24 to 48 hours with a simultaneous heparin infusion of 250 to 500 units/hour. Significant lysis occurred in 80% of cases, with 74% of the patients benefiting clinically. Minor bleeding, usually from puncture sites, occurred in 30% of the patients. Major hemorrhages, requiring transfusion or surgery, developed in four patients (8%). No hemorrhagic strokes or fatalities were directly attributable to SK infusion. Coagulation parameters were determined before infusion, 4 and 24 hours after infusion, and every 24 hours thereafter. Significant alterations of coagulation parameters developed promptly, but were not very useful in predicting either clinical response or hemorrhage. Selective intra-arterial infusion of SK is a moderately effective and safe therapeutic technique in acute peripheral arterial thromboembolic disease. A comparison with prior reports suggests that selective low-dose infusion provides a moderate gain in benefit-risk ratio over systemic infusion.

Is carotid endarterectomy beneficial in prevention of recurrent stroke?

Of 456 consecutive carotid endarterectomies performed at the University of California, San Diego, 127 were in patients who had sustained a previous completed stroke and had recovered with minimal but permanent neurologic deficits (PNDs). Operative mortality for the entire series was 0.9%, but it was 3.1% for the stroke group. A postoperative PND was observed in 2.1% of patients without neurologic deficits but occurred in 3.9% of the patients after stroke. A 97% one-to-ten-year follow-up was obtained. The total early and late serious morbidity and mortality in this surgically treated series of patients after stroke was 24% at five years. We conclude that carotid endarterectomy for the prevention of recurrent stroke carries a high risk and may not be superior to nonoperative treatment.

Should aortography be used routinely in the elective management of abdominal aortic aneurysm?

Until recently aortography was performed routinely for elective abdominal aortic aneurysm at our institution. A death resulting from this procedure prompted us to evaluate this policy by a retrospective study of 105 elective aneurysm patients. These studies identified 21 renal artery stenoses, 2 renal artery aneurysms, 2 cases of multiple renal arteries, 8 celiac stenoses, 6 superior mesenteric artery stenoses or occlusions, and a number of peripheral occlusive processes and associated iliac aneurysms. However, the impact of these findings on surgical management was limited to six renal artery reconstructions: one for reimplantation of a renal artery arising from the aneurysm, one for serious hypertension, and four in normotensive patients with severe arterial stenosis. No celiac or mesenteric reconstructions were undertaken, and no visceral complications ensured. In only one patient, the one with renal artery reimplantation, was the angiographic information unsuspected and significant for operative management. This did not appear to justify the risk and expense involved in routine preoperative aortography.

The current status of carotid artery surgery.

The natural history of extracranial cerebrovascular disease and available alternatives in its treatment are reviewed. An evaluation of the evidence suggests that carotid endarterectomy is the treatment of choice in patients with transient ischemic deficits, provided that an anatomically appropriate lesion can be identified. These patients have a 25-38% chance of stroke if untreated, which can be reduced to 5-10% by carotid endarterectomy. Patients with asymptomatic carotid stenosis who are good operative risks are also candidates for surgery, although this issue remains controversial. Patients with small asymptomatic ulcerated carotid plaques have a relatively benign prognosis and should not undergo preventive carotid surgery. Carotid surgery is occasionally indicated in patients with vertebral basilar insufficiency and carotid stenoses, fibromuscular dysplasia, or carotid kinks associated with symptoms of ischemia. Carotid endarterectomy may be performed with an overall mortality of 1-2% and morbidity of 2-5% if the patients are carefully selected and the surgical team is expert.

Nonaneurysmal suppurative aortitis.

Two patients had nonaneurysmal suppurative aortitis. In one, the aortic ruptured and the patient died. The second patient had Salmonella sepsis and occlusion of the infrarenal aorta. He was treated with aortic resection and extra-anatomic bypass, but died 20 months later of an unrelated illness. Patients with Salmonella sepsis who are over 50 years of age or who are suspected of having aortic atherosclerosis should be evaluated carefully for aortitis since rupture or aneurysm formation is associated with a dismal prognosis.

Pulmonary haemodynamics and function immediately after canine left lower lobe preservation.

After temporary reimplantation of the left lower lobe in dogs, the effects of various preservation techniques on the canine lung were assessed. Vascular resistance, shunt fraction, weight gain, and airway pressure were found to reflect and predict the effectiveness of various preservation techniques compared with reported survival data.

Esophagogastrostomy. Analysis of 55 cases.

At the New York University Medical Center from January, 1969, through December, 1973, esophagogastrostomies were performed in 56 patients. In 30 (Group A), fundoplications were combined with the esophagogastrostomies; in the other 26 (Group B), esophagogastrostomies only were performed. These two groups have been compared in an effort to determine the effectiveness of fundoplication in preventing gastric reflux following esophagogastrostomy. The operative mortality rate (10 per cent) and the 3 year survival rate (20 per cent) were approximately equal in the two groups. Clinical evidence of reflux was noted in 10 per cent of Group A and 47 per cent of Group B patients, while complications of reflux were noted in 5 per cent of Group A and in 33 per cent of Group B patients. The results of the present study suggest that fundoplication, while not prolonging survival, does prevent the symptoms and complications of gastric reflux and improves the quality of survival in these unfortunate patients. This leads us to recommend the routine use of fundoplication with esophagogastrostomy in patients with carcinoma of the esophagus and gastric cardia.