Temporary monocular blindness associated with acute carotid thrombosis: a case report.

We report upon a patient with multiple, progressive episodes of temporary monocular blindness associated with acute thrombosis and a critical internal carotid artery stenosis. Carotid angiography demonstrated an anatomically compelling situation consisting of a critical reduction of flow distal to a preocclusive internal carotid artery stenosis accompanied by intraluminal thrombus. The patient was managed successfully by urgent thrombectomy and carotid endarterectomy. This case report highlights principles in management of patients with the unstable neurologic condition of temporary monocular blindness associated with an anatomically compelling situation demonstrated on angiography.

Current clinical concepts in perioperative anticoagulation.

Management of patients with significant risks for thromboembolism in the perioperative period requires consideration of both risks of thromboembolism and risks of anticoagulant therapy. Patients who are receiving warfarin therapy because of recent venous thromboembolism, nonvalvular atrial fibrillation, and mechanical heart valves are at increased risk during the interval when the warfarin is discontinued and when the international normalized ratio is at a subtherapeutic level. In patients with an acute venous thromboembolic event within the past month, the use of intravenous heparin appears to be justified both preoperatively and postoperatively. If the venous thromboembolic event was within the past 2 to 3 months, use of intravenous heparin appears justified in the postoperative period. More than 3 months after an acute episode of venous thrombophlebitis, the relatively low risk of recurrence does not appear to justify the risks of complications from intravenous heparin. Patients with increased risks of arterial embolism, specifically those with nonvalvular atrial fibrillation and mechanical heart valves, are generally not at sufficient risk of arterial embolism to justify use of intravenous heparin during the perioperative subtherapeutic international normalized ratio interval when warfarin is withheld. A potential increased risk of recurrent arterial embolism when the preceding event was within a month suggests that elective surgery should be deferred beyond a month whenever possible in such patients. The use of fixed-dose, subcutaneous low molecular weight heparin has been observed to have advantages over use of unfractionated intravenous heparin both in terms of safety and efficiency. Further refinements in management of patients with significant risks of thromboembolism may occur with increased experience with low molecular weight heparin.

Concurrence of anaphylaxis and acute heparin-induced thrombocytopenia in a patient with heparin-induced antibodies.

We report the occurrence of acute heparin-induced thrombocytopenia in a patient with anaphylaxis that began immediately after an intravenous bolus dose of unfractionated heparin. This case report is the first to document the concurrence of these 2 reactions to heparin. An abrupt fall in platelet count was documented immediately after the anaphylactic response. Study results for antibodies characteristic of heparin-induced thrombocytopenia were positive in 2 assays: serotonin release assay and heparin platelet factor 4 enzyme-linked immunosorbent assay. The patient's antibody was exclusively immunoglobulin G. Any explanation for the relationship between the antibody response observed and the histamine release remains speculative.

Iliac vein compression syndrome: case report and review of the literature.

Iliac vein compression syndrome is a clinical condition that occurs as a result of compression of the left iliac vein between the right iliac artery and the fifth lumbar vertebrae. Patients usually have marked edema of the left leg. We report a case of a 16-year-old man who sought medical attention with significant left lower leg edema and four previous episodes of left leg cellulitis. Evaluation demonstrated venous hypertension as a result of left iliac vein compression. The patient underwent surgical correction; his symptoms resolved. Details and management of the case are presented and discussed. A review of the current literature regarding this condition also is included.

Benzodiazepine receptor ligands with different intrinsic efficacies alter ethanol intake in alcohol-nonpreferring (NP) rats.

Benzodiazepine (BDZ) receptor ligands with varying intrinsic efficacies [RO19-4603, 0.02-0.15 mg/kg; FG 7142 1-16 mg/kg; DMCM, 1-8 mg/kg; RO16-6028 (bretazenil), 8-32 mg/kg] in modulating GABAergic activity were examined for the ability to alter palatability-induced ethanol (EtOH) intake in the alcohol-nonpreferring (NP) line of rats. NP rats on a 22-hour fluid-deprivation schedule were given 2-hour daily access to a 10% (v/v) EtOH/3% (g/v) polycose solution and water. Average EtOH intake was 2.1 +/- 0.2 g/kg/2 hours, and water intake was 17.1 +/- 0.9 ml/2 hours. During the initial 15 minutes of the 2-hour session, RO19-4603, the imidazothienodiazepine partial inverse agonist reduced EtOH intake to 19% of control values at 0.04 mg/kg and completely suppressed drinking of the EtOH solution at 0.15 mg/kg. Twenty-four-hour postdrug administration, the 0.08-mg/kg dose of RO19-4603 completely suppressed drinking of the EtOH solution at the 60-minute interval, and the 0.15-mg/kg dose reduced intake to 20% of control levels at the 15-minute interval. FG 7142, the partial beta-carboline inverse agonist reduced EtOH drinking at the 60-minute interval with the 1-mg/kg dose, and the 16-mg/kg dose reduced water intake at the 15-minute interval. DMCM, the full beta-carboline inverse agonist, significantly reduced water intake at 15 minutes (4 and 8 mg/kg), and the same doses caused a substantial increase in EtOH drinking at the 120-minute interval. The anxiolytic agent bretazenil (16 and 32 mg/kg) increased EtOH consumption during the initial 15 minutes to 270% to 425% of control levels, and water intake increased by the end of the 2-hour session to as much as 210% of control following administration of the 32-mg/kg dose. These findings support existing evidence suggesting that BDZ receptor ligands may modify neuronal processes that mediate some reinforcing and/or aversive properties of alcohol. They further demonstrate a potential importance of the GABAA-BDZ receptor complex in mediating palatability- (environmentally) induced EtOH drinking even in rats selectively bred for low alcohol preference.

Severe upper limb ischemia.

Severe upper limb ischemia is uncommon, and patterns typical of lower limb ischemia are seldom seen. The conditions of 31 patients with actual or threatened gangrene or severe disability were evaluated from 1969 through 1978. Causes of ischemia included emboli, arteriosclerotic occlusions, trauma, thoracic outlet compression, and small-artery occlusions associated with Raynaud's phenomenon, rheumatoid arthritis, or scleroderma. Five patients had emboli from lesions in peripheral arteries, and two patients had ulnar artery occlusions. Twenty-three patients had operations with no deaths. There was one operative failure. Operative angiograms were used routinely. Patients with emboli from the heart received heparin sodium after operation. Sympathectomy improved the conditions of two patients with Raynaud's phenomenon and of one patient with ulnar artery occlusion. One third of the patients had significant arteriosclerotic lesions in other locations.

Myocardial distribution of asanguineous solutions retroperfused under low pressure through the coronary sinus.

Asanguineous retroperfusion of the coronary sinus can penetrate a significant microvascular bed in proximity to myocardial cells. Myocardial regions permeated by this technique are located in the apex, septum, endocardium, and free wall of the left ventricle. Retrograde drainage patterns heavily favor the Thebesian-sinusoid system over the capillary-arterial route by more than a 3:1 ratio. Microscopic india ink preparations, regional flow studies, and retrograde roentgenograms indicate that asanguineous cardioplegic agents and core cooling can penetrate important regions of the heart at a microvascular level and may be an alternative route when routine antegrade perfusion via the coronary arteries is unavailable or disadvantageous. Because the flows established are primarily venous (Thebesian), the use of this route for chronic revascularization may be limited as the metabolic implications have not been fully investigated.

Aneurysm of anomalous right subclavian artery.

A 67-year-old man presented with a mediastinal mass and multiple arterial emboli to the right hand caused by an aneurysm of an anomalous right subclavian artery. Operative management was successful. We have reviewed other reported cases of this lesion.

Tracheo-innominate artery erosion: Successful surgical management of a devastating complication.

Successful management of a patient with tracheo-innominate artery erosion requires the rapid institution of specific resuscitative and operative measures. Ten patients seen at the Charity Hospital of Louisiana in New Orleans and 127 documented cases from the world literature were analyzed regarding predisposing factors, diagnostic features, resuscitative measures and operative treatment. Diagnoses associated with abnormal neck positioning were seen in 48% of patients with tracheo-innominate erosions. In 69% of 96 instances, the site of erosion was located at the cannula end and implicates excessive anterior pressure. Caution is recommended in those patients with abnormal neck positions, low placed tracheostomy stomas and individuals with asthenic habitus. Resuscitative measures were highly successful when the tracheal ballon was inflated or when the method of retrosternal finger pressure was used. All personnel providing care for patients with tracheostomies should be aware of the initial measure of ballon inflation. Operative measures which permanently interrupted the innominate artery in the area of possible future erosion were the most successful. Of the 22 cases in which the innominate artery was sacrificed, only one had evidence of cerebral ischemia. Timely institution of proper measures can result in salvage of an unexpected number of these otherwise dramatic fatalities.

Protective effect of methylprednisolone on the heart during ischemic arrest.

Although corticosteroids have been shown to stabilize lysosomal membranes and prevent release of hydrolytic enzymes, the mechanism of membrane stabilization remains obscure. The few reports regarding the use of steroids in myocardial ischemia have been conflicting. This study was undertaken to determine if a pharmacologic dose of the glucocorticoid methylprednisolone would protect the heart during ischemic cardiac arrest. A randomized double-blind study was performed in 25 dogs. Biochemical and hemodynamic parameters were assessed during and after cardiopulmonary bypass and after 30 minutes of ischemic cardiac arrest. Animals were divided into two groups. Group I served as controls and consisted of dogs injected intravenously with the vehicle of methylprednisolone 18 hours and 1 hour prior to experiment. Group II comprised dogs injected with methylprednisolone, 30 mg. per kilogram, IV, at the same time periods. Blood pH, gases, and electrolytes were measured; aortic, left atrial, and left ventricular pressures were monitored; the first derivative of the left ventricular pressure (dp/dt max.) was also determined. Arterial and coronary sinus blood samples were assayed for lactate levels and activity of the lysosomal enzyme, beta-glucuronidase. Left ventricular muscle was assayed for the nucleotides cyclic adenosine 3',5' monophosphate (AMP) and cyclic guanosine 3',5' monophosphate (GMP). Following restoration of coronary flow, mean aortic and left ventricular systolic pressures and left ventricular contractility as determined by dp/dt max. and dp/dt max./IP were depressed in both groups as expected but were significantly higher in Group II than in Group I (p less than 0.05). An increase in levels of both cyclic nucleotides occurred in each group during ischemia, but this increase in cyclic GMP was significantly greater in Group I (p less than 0.05). beta-glucuronidase activity and myocardial potassium loss as determined in coronary sinus blood were both significantly greater in Group I than in Group II (p less than 0.05). Results of this study demonstrate that pretreatment with a pharmacologic dose of methylprednisolone significantly enhances cardiac recovery after ischemia. Lysosomal membrane stability and modulation of cyclic GMP levels may be critical determinants in the mechanism of cardiac ischemia.

Cardiac contusion: a capricious syndrome.

Cardiac contusions are being recognized with frequency. Among 507 patients with non-penetrating chest injuries, 210 had serial electrocardiograms sufficient to evaluate the heart. Forty-five of these 210 patients (21%) had cardiac contusions. These 45 patients and 3 others who were confirmed to have cardiac contusions at necropsy, comprise the 48 patients in this series. Life-indangering cardiac complications occurred in 14 (29%) of the 48 patients, and 4 patients died. The development of cardiac complications following cardiac contusions appears to have a significant relationship to the presence of shock, hypoxia and to factors related to the severity of multiple injuries. These observations have therapeutic implications in management of patients with cardiac contusions through prevention of hypovolemia and hypoxia and avoidance of fluid overload as well as treatment of specific cardiac complications.