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Biomedical subjects

D P Link

Publications and source records attributed to D P Link.

49 records · Page 3Linked to original sources

Arteriography before needle puncture or renal hilar lesions.

We report on 2 patients with cystic-appearing lesions in the renal hilus that were detected on urography. In 1 case an ultrasound study confirmed a cystic mass but an arteriogram revealed a renal artery aneurysm. The arteriogram before the contemplated puncture of the renal hilar mass prevented an inadvertent puncture. The information about the arterial anatomy helped preoperative planning, which resulted in successful repair of the aneurysm by microdissection and autotransplantation.

Adult↗

Palliative embolization of fibrosarcoma for control of tumor-induced hypoglycemia.

A 77-year-old woman with prior long-standing insulin-dependent diabetes presented with malignant hypoglycemia secondary to insulin-like substances excreted from a large unresectable fibrosarcoma of the left thigh. Partial embolization of the tumor supply from the deep femoral artery was performed using 150-250 microns polyvinyl alcohol foam particles. After embolization, the patient's serum glucose levels reverted to normal and she could be discharged from the hospital.

Aged↗

Histopathologic appearance of arterial occlusions with hydrogel and polyvinyl alcohol embolic material in domestic swine.

PURPOSE: This study observes the histologic changes resulting from a hydrogel embolic agent (polyacrylonitrile [PAN]) compared with polyvinyl alcohol particles (PVA) of similar size. MATERIALS AND METHODS: Hepatic and renal embolizations were performed in 13 domestic swine by selecting small (1-mm) branches utilizing a coaxial 3-F microcatheter. The hydrogel embolic agent (tantalum-loaded and plain) and PVA were delivered through microcatheters. The longest follow-up period was 8 weeks. Postmortem examination of the embolized tissues included gross examination and histologic analysis. RESULTS: Tantalum-loaded PAN particles were radiopaque and seen in groups fluoroscopically and individually with specimen radiography. Histologic studies showed similar luminal and cellular response to PVA and the hydrogel embolic agents. The arterial lesion induced by the hydrogel embolic agents led to an absence of the arterial wall locally in the area of deployment. Hydrogel embolic particles became surrounded in fibrous connective tissue with no arterial wall. PVA and porous hydrogel capsules produced an inflammatory response, resulting in less wall reorganization, and surrounding fibrous connective tissue at 8 weeks than the solid PAN particles. CONCLUSION: These hydrogel embolic create a permanent arterial occlusion by transmural arterial damage. Mechanical effects and, to a lesser degree, inflammatory changes are responsible.

Acrylic Resins↗

New videodensitometric method for measuring renal artery blood flow at routine arteriography: validation in the canine model.

A contrast medium was injected in the aortic arch and selectively in a renal artery to estimate the renal blood flow as a percentage of the cardiac output by the videodensitometric (VD) method. Twenty-six paired VD measurements in four mongrel dogs were obtained and the results compared to electromagnetic (EM) flow readings from the aortic arch and a renal artery. The relative renal blood flow estimated by the VD method averaged 9.1% and correlated with the EM flow average of 9.6% with r = 0.96. Previous in vitro investigations of relative flow in a model have now been validated in vivo. These results suggest that videodensitometry could be a clinical tool for measuring renal blood flow in conjunction with routine arteriography.

Absorptiometry, Photon↗

Assessment of cerebral blood flow in man by video dilution technique: a preliminary report.

Video dilution technique (VDT) is currently performed in conjunction with routine cerebral angiography to determine carotid blood flow in humans. Preliminary results indicate that the blood flows (as a percentage of cardial output) of the common, internal, and external carotid arteries are 8.5%, 5.5%, and 3.0%, respectively (SD less than 1%). In contradistinction to previous techniques, VDT provides a safe and highly accurate method of determining carotid blood flow in human subjects. The usefulness of this technique in normal and pathologic states is discussed.

Brain↗

Assessment of peripheral blood flow in man by video dilution technique: a preliminary report.

Video dilution technique is now available for clinical use in evaluating patients with peripheral vascular disease. The measurements can easily be performed in any modern angiographic suite. The only additional equipment required is a videodensitometer, video tape recorder, and a strip chart recorded. The new technique has been developed and tested in a hydrodynamic model and compared to volumetric flows. Further, the video dilution technique has been compared to electromagnetic flow readings using a canine model to measure the cerebral, renal, splanchnic, and extremity circulation and has proven to be extremely accurate (n = 389; r = 0.99). By applying the technique to patients with peripheral vascular disease, it is possible to evaluate the hemodynamic significance of stenotic lesions and arteriovenous shunts. Other uses of video dilution technique include evaluating the effects of vasoactive drugs and the adequacy of transluminal angioplasty.

Adult↗

Alteration of renal blood flow during sequential embolization of the canine kidney.

Experimental embolization of the renal artery with cross-linked dextran (CLD) microspheres was performed in 6 dogs. The blood flow was monitored by electromagnetic flow meter (EM) in 3 dogs and by video dilution technique (VDT), adapted to an angiographic digital subtraction system, in a second group of 3 dogs. Retrograde flow in the embolized renal artery was detected by 99Tcm microspheres. Sequential emboli produce a predictable and equal flow response with both measuring techniques. Thus, the less invasive VDT can be used in the clinical setting to optimize and control embolization procedures. This type of flow monitoring has great potential in alerting the angiographer when approaching the risk level for retrograde flow.

Animals↗

On-line monitoring of sequential blood flow reduction during splenic embolization.

Partial embolization of the spleen has been well established for the treatment of hypersplenism. A weakness of the technique is the lack of an objective method to quantitate the flow reduction during the procedure. The video dilution technique (VDT) has earlier been used to measure blood flow in regional arteries using video cassette replay. By adapting the VDT concept of relative flow to digital subtraction angiography, it is possible to calculate the flow reduction instantly following each injection of embolic material. We present a case of partial splenic embolization where the flow in the splenic artery was reduced to a predetermined level of 50 per cent of baseline flow. The clinical results were excellent. By observing the clinical results of partial embolization, terminated at different levels of flow reduction, it will be possible to optimize the results and prevent overembolization.

Aged↗

Carotid blood flow in man determined by video dilution technique: 1. Theory, procedure, and normal values.

The blood flows in the common, internal, and external carotid arteries were determined as a percentage of the cardiac output by video dilution technique in 20 normal subjects during routine angiography. Nine women and 11 men, ages 19-63 years, displayed a mean flow in the common carotid of 8.5% (SD +/- 0.9%; n = 40); internal carotid, 5.3% (SD +/- 1.0%; n = 24); and external carotid, 3.2% (SD +/- 0.4%; n = 24). Relative flow is calculated by a modification of the Stewart-Hamilton principle. The technique is fast, simple, highly accurate, and avoids the errors connected with previous videodensitometric mean transit time techniques. The method can be used in routine angiography without prolonging the catheterization procedure or adding to the patient's risk or cost.

Adult↗

Carotid blood flow in man determined by video dilution technique: II. Vascular abnormalities.

Carotid blood flows were evaluated in 31 individuals with vascular abnormalities using the video dilution technique. In patients with stenoses, angiographically estimated at 70%, blood flow was usually, but not always, measured less than normal. The technique proved to be useful in the evaluation of the efficiency of collateral arterial pathways and in the evaluation of superficial temporal-middle cerebral arterial bypass grafts. It was also helpful in estimating contralateral increase in arterial flows with cross compression techniques for the preoperative evaluation of patients subjected to carotid sacrifice. In a limited number of patients video dilution flows correlated with the degree or proximal arterial spasm and were useful in the preoperative study of these patients. The demonstration of flow abnormalities in patient with seizure disorders may be useful in the medical and surgical management of these individuals.

Adult↗