Acute arterial thrombosis associated with cocaine abuse

PURPOSE: Cocaine-induced arterial thrombosis is uncommon, and most reported cases involved small-diameter vessels such as the cerebral and coronary arteries. This study was undertaken to review our experience with peripheral arterial thrombosis presumed caused by cocaine abuse. METHODS: Hospital records were reviewed for all patients admitted over 10 years with acute arterial occlusion involving the peripheral arterial system. Patients with confirmation of cocaine use or of its derivative, crack cocaine, within 24 hours of hospital admission formed the basis of this study. Symptoms at presentation, management, and outcome in these patients were reviewed. RESULTS: Three hundred eighty-two patients with acute peripheral arterial occlusion were identified during the study period. The presumptive diagnosis of cocaine-induced arterial occlusion was made in 5 patients (4 men, mean age 38 years). Cocaine use was achieved via intranasal inhalation in 2 patients (40%), whereas the 3 remaining patients smoked crack cocaine (60%). The mean time between cocaine use and onset of arterial thrombosis was 9.2 hours (range, 2-20 hours). Symptoms at presentation included acute limb ischemia without pedal Doppler signals (3 patients, 60%) and abdominal pain without femoral pulses (2 patients, 40%). Arterial occlusion was confirmed on angiograms in all patients, which revealed aortic thrombosis in 1 patient (20%), iliac thrombosis in 2 patients (40%), superficial femoral artery thrombosis in 1 patient (20%), and popliteal artery occlusion in 1 patient (20%). Surgical thrombectomy was successfully performed in 4 patients (80%), and 1 patient (20%) underwent successful thrombolytic therapy for femoropopliteal artery occlusion. There was no perioperative mortality. All 5 patients who were discharged were available for follow-up (mean, 36 months; range, 6-75 months). There was 1 late death from myocardial infarction. In 1 patient recurrent lower extremity arterial thrombosis developed after 28 months, which was successfully treated with thrombolytic therapy. CONCLUSIONS: Our study underscores cocaine abuse as a potential cause of acute arterial thrombosis. Cocaine-induced arterial thrombosis should be suspected in patients with recent history of cocaine abuse with acute limb ischemia without an identifiable source or overt cardiovascular risk factors. Prompt angiography with operative or endovascular intervention should be performed to avert arterial ischemic sequelae.     

Abdominal aortic surgery in patients with human immunodeficiency virus infection

PURPOSE: Human immunodeficiency virus (HIV) infection is known to cause acquired immune deficiency syndrome, which has been associated with a wide array of cardiovascular pathologies. This report examined the clinical outcome of patients infected with HIV who underwent abdominal aortic reconstruction for aneurysm or occlusive disease. METHODS: Hospital and clinic records of all patients with HIV infection who underwent an abdominal aortic operation were reviewed during an 11-year period. Relevant risk factors and clinical variables were assessed for surgical outcome. RESULTS: Forty-eight HIV patients (mean age 54 +/- 13 years) were identified who underwent abdominal aortic bypass grafting during the study period. Indications for aortic operation included aneurysm (n = 20) and aortoiliac occlusive disease (n = 28). All patients underwent successful aortic reconstructions without intraoperative mortality. Postoperative complications and in-hospital mortality occurred in 16 patients (33%) and 7 patients (15%), respectively. The mean follow-up period was 41 months. Life-table survival rates in aneurysm and occlusive patients at 60 months were 43.2% +/- 5.3% and 46.3% +/- 7.4% (not significant), respectively. Multivariate analysis showed that low CD4 lymphocyte counts (< 200/microL, P <0.05) and hypoalbuminemia (<3.5 g/dL, P <0.05) were risk factors for postoperative complications. CONCLUSION: Perioperative morbidity and mortality rates are high in HIV patients undergoing an abdominal aortic operation. Low CD4 lymphocyte counts and hypoalbuminemia are associated with poor clinical outcomes in HIV patients undergoing abdominal aortic reconstruction.     

Amino acids do not alter the insulin-induced activation of the insulin signaling pathway in neonatal pigs

Feeding stimulates protein synthesis in skeletal muscle and liver of neonates and this response can be reproduced in muscle by the infusion of insulin or amino acids and in liver by the infusion of amino acids, but not insulin. Activation of insulin signaling components leading to translation initiation is associated with the feeding-induced stimulation of muscle protein synthesis in neonates. In this study, we examined the individual roles of insulin and amino acids in the activation of insulin signaling components leading to translation initiation, specifically, the insulin receptor (IR), insulin receptor substrate 1 (IRS-1), phosphatidylinositol 3-kinase (PI 3-kinase), protein kinase B (PKB) and ribosomal protein S6. Insulin secretion was blocked by somatostatin in food-deprived, 7-d-old pigs (n=8-12/group); insulin was infused to achieve plasma levels of approximately 0, 17, 52, and 255 pmol/L (approximately 0, 2, 6, 30 microU/mL), and amino acids were clamped at food-deprived or fed levels. In skeletal muscle, insulin increased the activation of IR, IRS-1, PI 3-kinase, PKB and S6 and stimulated protein synthesis. In liver, insulin increased the activation of IR, IRS-1, PI 3-kinase, PKB and S6, but had no effect on protein synthesis. Raising amino acids from the food-deprived to the fed level did not alter the insulin-induced activation of IR, IRS-1, PI 3-kinase and PKB but increased S6 phosphorylation and protein synthesis in skeletal muscle and liver. The results suggest that the stimulation of protein synthesis in muscle by insulin involves activation of insulin signaling components, and the stimulation of protein synthesis in muscle and liver by amino acids occurs by mechanisms independent of the early steps of this pathway. Furthermore, amino acids do not alter the insulin-stimulated activation of early steps in the insulin signaling pathway.     

Endovascular treatment of an endoleak causing rupture of a previously bypassed popliteal aneurysm. A case report

Enlargement of a previously bypassed popliteal aneurysm is rare. However, the possibility exists for persistent aneurysm expansion via geniculate collaterals. The authors report herein a patient who underwent successful endovascular treatment of a ruptured popliteal aneurysm that had been previously bypassed and presumably excluded.     

The magnetic resonance imaging of musculoskeletal hemorrhage

Hematomas in the extremities can present clinically as a soft tissue mass. Hematomas can usually be distinguished from neoplasia on MR by the signal patterns of hemoglobin breakdown products, which are dependent on the chemical bonding and oxidation state of hemoglobin iron. Beginning with a discussion of relevant atomic electronic structure, this review will examine how oxyhemoglobin, deoxyhemoglobin, methemoglobin, and hemosiderin, the principal iron compounds occurring in the various stages of a hematoma, affect its appearance on MRI. Received: 26 August 1999 Revision requested: 6 October 1999 Revision received: 27 October 1999 Accepted: 27 October 1999     

Is misoprostol safe for labor induction in twin gestations?

OBJECTIVE: To compare the safety and efficacy of intravaginal misoprostol to oxytocin for the induction of labor in twin gestations. METHODS: All twin gestations that underwent induction of labor with misoprostol or oxytocin during a 4-year period were identified from the Mount Sinai obstetrical database. Only twins > or = 34 weeks with a vertex presenting twin A were included. Labor and delivery characteristics, maternal complications and neonatal outcomes were compared between the two groups. RESULTS: Of 134 patients with twins, 57 initially received misoprostol and 77 received oxytocin. These groups had similar demographics, but women who received misoprostol had less cervical dilation (0.8 vs. 2.2 cm, p < 0.0001) and were less likely to be multiparous (19% vs. 44%, p = 0.003). There was a shorter length of induction to delivery (7.8 hours vs. 15.1 hours, p = 0.001) and a trend toward a lower cesarean section rate (16.9% vs. 31.6%, p = 0.06) in the oxytocin-only group. There were no cases of uterine rupture or maternal mortality in this series. There were no significant differences in neonatal outcomes between the two groups, but the sample size was underpowered to detect significant differences between the groups. CONCLUSIONS: Misoprostol and oxytocin both appear to be safe and efficacious for use in inductions of labor in twins in this limited retrospective investigation. The safety of these agents with regard to neonatal outcomes should be confirmed by larger studies.