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Biomedical subjects

C B Heilman

Publications and source records attributed to C B Heilman.

27 records · Page 2Linked to original sources

Enlargement of basilar artery aneurysms following balloon occlusion--"water-hammer effect". Report of two cases.

Two patients with distal basilar aneurysms were treated with intra-aneurysmal balloon occlusion. After apparently successful therapy, follow-up angiograms demonstrated aneurysm enlargement with balloon migration distally in the sac. Geometric mismatch between the base of the balloons and the aneurysm neck together with transmitted pulsation through the 2-hydroxyl-ethylmethacrylate (HEMA)-filled balloon directly contributed to aneurysm enlargement. In this report, the authors discuss the problems of progressive aneurysm enlargement due to a "water-hammer effect" and the possibility of hemorrhage following subtotal occlusion.

Adult↗

Temporary balloon occlusion of a proximal vessel as an aid to clipping aneurysms of the basilar and paraclinoid internal carotid arteries: technical note.

One aneurysm of the basilar artery and three large, paraclinoid aneurysms of the internal carotid artery (ICA) were treated with the aid of intraoperative temporary balloon occlusion of the vessel. Optimal clip placement was confirmed using intraoperative angiography. This technique provided excellent proximal vascular control and for the large aneurysms of the paraclinoid ICA obviated the need for surgical exposure of the ICA in the neck. We think this is a useful adjunct in the surgical management of aneurysms of both the basilar artery and proximal ICA.

Adult↗

Elimination of a cirsoid aneurysm of the scalp by direct percutaneous embolization with thrombogenic coils. Case report.

Cirsoid aneurysms of the scalp are notoriously difficult lesions to manage. The authors report a patient in whom a large traumatic cirsoid aneurysm of the scalp was eliminated using a combined neurosurgical and interventional neuroradiological approach. Transarterial embolization was utilized to reduce arterial blood supply to the fistula. Thrombogenic Gianturco spring coils were then introduced via direct percutaneous puncture of the aneurysm. The aneurysm thrombosed and the multiple tortuous scalp vessels disappeared. One month after embolization, a small area of skin necrosis over the aneurysm necessitated surgical excision of the lesion. The thrombosed aneurysm was easily resected with minimal blood loss. Percutaneous embolization with thrombogenic coils in this case was a safe and effective ablative technique.

Adult↗

Flow dynamics in the human carotid artery: I. Preliminary observations using a transparent elastic model.

PURPOSE: We developed an elastic, transparent, life-size model of the cranial vessels that allowed us to visualize carotid artery flows directly, and wish to report our observations and recorded data. MATERIALS AND METHODS: The brachiocephalic arteries of 12 adult cadavers were cannulated and infused with acrylic. The heads were dissolved in alkali and, using a "lost wax" technique, a silicone model that reflected the shape and size of the original artery was produced. These models were connected to a closed circuit of flowing fluid. The fluid was rendered opaque by injecting isobaric dyes at various points in the streams. RESULTS: These dye opacified slipstreams showed a relatively low flow area visible in the posterior and lateral aspect of the carotid bulb that acted as an internal buffer, and directed the more posterior lateral slipstreams anteriorly and at the same time increased their velocity. The cervical internal carotid artery was relatively straight and showed flow patterns that were essentially laminar. In the petrous internal carotid artery, the dye-opacified slipstreams began a helical flow pattern, and areas of flow reversal became apparent along the inner aspect (lesser curvature) of the bend. The central slipstreams tended to flow in a straighter line, passing close to, and sometimes striking the wall of, the outer portion (greater curvature) of the bend. In the cavernous internal carotid artery, helical flow continued. The central slipstreams struck the outer surface (greater curve) of the arterial bend. The point that the central slipstream struck the wall was more distal during systole than during diastole. At the supraclinoid section laminar flow again became established. Certain slipstreams selectively entered individual cranial branches. CONCLUSION: The model we describe should allow more accurate study of complicated flow dynamics in vessels supplying the brain.

Blood Flow Velocity↗

Iotrol, a new myelographic agent: 1. Radiography, CT, CSF clearance, and brain penetration.

Four new myelographic agents, metrizamide, iopamidol, iohexol, and iotrol, were studied in the subarachnoid space of cynomolgus monkeys. Plain films and computed tomographic scans documented the transport of each material throughout the space and into the brain. At the concentration used (300 mg I/ml), all gave good radiopacity for myelography and delineation of the cerebral subarachnoid space. All four cleared similarly from the ventricular system. Metrizamide, however, penetrated the brain in greater degree and persisted longer than the other three agents. Next in persistence was iopamidol and least, and both statistically equal, iotrol and iohexol.

Animals↗

Flow in experimental berry aneurysms: method and model.

This study addresses two basic questions: What are the flow dynamics in aneurysms? Can these flows be modified to enhance retention of adhesive? Using Pyrex glass bifurcations, fluid flow was studied in a variety of aneurysms placed at varying positions around the bifurcations. Indicators injected into the slipstreams were recorded and studied both by stop-frame high-speed movie analysis and with 35 mm slides. Even at low-flow rates, a central slipstream strikes the apex of bifurcations, and may be partly responsible for the initial production of berry aneurysms. A low-pressure zone occurs at the lateral angle of bifurcations, probably explaining the formation of endovascular cushions. Flow into symmetrically placed narrow neck aneurysms did not occur. Indicator entered the aneurysm in a turbulent fashion only when there was orifice (lip) asymmetry. Both lip asymmetry and rapid flow favor intraaneurysmal turbulent flow.

Cerebrovascular Circulation↗

Endovascular packing of carotid bifurcation aneurysm with polyester fiber-coated platinum coils in a rabbit model.

PURPOSE: To assess the value of endovascular packing of intracranial bifurcation aneurysms with commercially available coils. METHODS: Carotid bifurcation aneurysms were surgically created in 12 New Zealand rabbits with subsequent assessment of the extent of aneurysm ablation following endovascular packing with polyester fiber-coated platinum coils. RESULTS: Follow-up angiograms obtained from 29 to 108 days postprocedures showed various degrees of aneurysm ablation. Complete obliteration of aneurysm dome occurred in seven out of eight rabbits, while ablation of aneurysm neck was successful in only one out of eight. No spontaneous thrombosis was observed in seven control animals over a 3-month period. Coils of various configurations used in this experiment all maintained stable intraaneurysmal position. Histologic examination of treated aneurysms consistently demonstrated extensive proliferation of spindle cells on the coil surface and in interstices between coils with channels lined by cells resembling endothelial cells. Organized thrombus was not a prominent feature. CONCLUSION: Endovascular packing of human bifurcation aneurysms with current commercially available polyester fiber-coated platinum coils may not result in complete obliteration of the aneurysm with reendothelialization occurring across the aneurysm neck.

Animals↗