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Biomedical subjects

B F Waller

Publications and source records attributed to B F Waller.

At least 109 records · Page 6Linked to original sources
PubMed1989

Thermal compression and molding of atherosclerotic vascular tissue with use of radiofrequency energy: implications for radiofrequency balloon angioplasty.

The combined delivery of pressure and thermal energy may effectively remodel intraluminal atherosclerotic plaque and fuse intimal tears. To test these hypotheses with use of a non-laser thermal energy source, radiofrequency energy was delivered to postmortem human atherosclerotic vessels from a metal "hot-tip" catheter, block-mounted bipolar electrodes and from a prototype radiofrequency balloon catheter. Sixty-two radiofrequency doses delivered from a metal electrode tip produced dose-dependent ablation of atherosclerotic plaque, ranging from clean and shallow craters with histologic evidence of thermal compression at doses less than 40 J to tissue charring and vaporization at higher (greater than 80 J) doses. Lesion dimensions ranged between 3.14 and 3.79 mm in diameter and 0.20 and 0.47 mm in depth. Tissue perforation was not observed. To test the potential for radiofrequency fusion of intimal tears, 5 atm of pressure and 200 J radiofrequency energy were delivered from block-mounted bipolar electrodes to 48 segments of human atherosclerotic aorta, which had been manually separated into intima-media and media-adventitial layers. Significantly stronger tissue fusion resulted (28.5 +/- 3.3 g) with radiofrequency compared with that with pressure alone (4.8 +/- 0.26 g; p less than 0.0001). A prototype radiofrequency balloon catheter was used to deliver 3 atm of balloon pressure with or without 200 J radiofrequency energy to 20 postmortem human atherosclerotic arterial segments. In 10 of 10 radiofrequency-treated vessels, thermal "molding" of both normal and atherosclerotic vessel wall segments resulted with increased luminal diameter and histologic evidence of medial myocyte damage.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon↗
PubMed1989

Pathology of transluminal balloon angioplasty used in the treatment of coronary heart disease.

The author provides insight into what happens to arteries or saphenous vein bypass grafts with angioplasty. The morphologic and histologic changes in coronary arteries and saphenous vein bypass grafts subjected to balloon dilation procedures are described. Mechanisms of action, causes of restenosis, and effects of adjacent nondilated vessels are discussed, as well as why some interventional procedures work, others do not, and some have a promising future.

Adult↗
PubMed1988

The old-age heart: normal aging changes which can produce or mimic cardiac disease.

The elderly segment of our society may triple by the year 2050. Specific cardiovascular data on the normal aging heart will be needed to provide proper medical and surgical therapy for this patient group. This report reviews normal aging changes of the very elderly heart. Expected or normal aging changes include brown atrophy of the myocardium, increased subepicardial fat, focal amyloid deposits, sigmoid-shaped ventricular septum, and calcific deposits in the aortic valve, mitral annulus and epicardial coronary arteries. Certain normal aging changes may produce clinical heart disease: aortic valve calcium (aortic stenosis), mitral valve annular calcium (mitral stenosis), amyloid deposits (amyloid heart disease). Certain normal aging changes may mimic heart disease: sigmoid-shaped ventricular septum (hypertrophic cardiomyopathy), mitral leaflet "buckling" (floppy mitral valve).

Aged↗
PubMed1988

Morphologic correlates of coronary angiographic patterns at the site of percutaneous transluminal coronary angioplasty.

Over the last 10 years considerable interest has been paid in the angiographic recognition of successful percutaneous transluminal coronary artery angioplasty (PTCA), complication of the technique, and angiographic predictors of restenosis. This report summarizes various angiographic patterns visualized at the site of angioplasty and correlates these patterns with morphologic findings. Of 66 patients undergoing PTCA for chronic or unstable angina pectoris, 76 PTCA sites were available for analysis. The two most common angiographic patterns at the angioplasty site (intimal flap = 43%, intraluminal haziness = 38%) correlated morphologically with intimal-medial splits with localized dissections (79%). Shallow, superficial intimal lesions, laminated thrombus, and adventitial tears accounted for the remaining morphologic changes. Eight PTCA sites without morphologic injury corresponded to smooth wall changes and spasm at angiography.

Aortic Dissection↗
PubMed1988

Fine-needle aspiration of metastatic atrial myxoma.

Atrial myxoma is the most common primary neoplasm of the heart, but "metastatic" or embolic phenomena are rare. The first reported case of "metastatic" atrial myxoma diagnosed by fine-needle aspiration biopsy is presented. It occurred in a 54-yr-old woman with multiple metastatic lesions. The cytologic and histologic findings of the fine-needle aspiration biopsy and subsequent surgical excision are presented as is a discussion of the incidence, origin, and clinical findings of atrial myxoma and the characteristics of its emboli.

Biopsy, Needle↗
PubMed1988

Carotid plaque morphology: correlation of duplex sonography with histology.

This study attempted to determine whether images obtained during preoperative duplex scanning correlated with histologic studies of carotid endarterectomy plaque and, therefore, might be useful in subsequent studies of the importance of plaque morphology and intraplaque hemorrhage. Forty-six endarterectomy specimens from 44 patients with satisfactory preoperative images were evaluated. The plaques were marked for orientation at the time of removal, and each plaque was imaged by duplex scanning in a saline bath. Magnification radiographs were made. Specimens were embedded in paraffin and slices 6 mu thick were made for staining with hematoxylin and eosin, Masson's trichrome, a modified Verhoeff-vanGieson stain, and von Kossa's stain. Overall, correlation between the preoperative images and the histologic specimens were good to excellent in 42 of 46 specimens. Scanning did not identify three cases of extensive recent intraplaque hemorrhage, however, and one instance of plaque calcification was missed. We conclude that duplex images correlate well with histologic studies except in some cases of recent intraplaque hemorrhage. Duplex imaging is valuable in the correlation of plaque morphology with symptoms for long-term studies. The accuracy of the technique may be improved by using post-processing on static images and in vitro scanning of endarterectomy specimens.

Aged↗
PubMed1988

Radiofrequency balloon angioplasty. Rationale and proof of principle.

Post-angioplasty restenosis (PARS) in atherosclerotic lesions of medium and small arteries occurs in about one-third of cases in the first year following percutaneous transluminal angioplasty (PTA) (early PARS). PARS includes acute spasm, dissection with reclosure, elastic recoil, fibrocellular proliferative response, and progressive atheromatous disease. Fibrocellular proliferation (possibly initiated by platelet derived growth factor) is felt to be culpable in many cases of early PARS (months). Pharmacologic regimens, stents, and thermal welding of the intimal-medial cracks of PTA are among the interventions being developed to deal with PARS. Radiofrequency (RF) current as a source of thermal energy may be useful in combination with balloon angioplasty to reduce PARS. Ideally, this combination would (1) weld intimal-medial cracks of PTA; (2) mold plaque and normal vessel to increase lumen diameters without creating intimal-medial cracks; and (3) destroy medial smooth muscle cells and multipotential cells (cellular substrate of PARS). Canine in vivo studies have established the feasibility of RF-mediated vascular tissue welding. Human aortic specimens (N = 28) were manually dissected into intima-media and media-adventitia layers. Bipolar RF energy (650 KHz, total 300 J) and mechanical pressure (1 atm) (experimental group, N = 24) or mechanical pressure alone (control group, N = 4) were applied to the reapposed specimen layers in a special chamber. The chamber was modified with a bipolar electrode designed to reproduce that planned for an RF balloon angioplasty catheter. Welding was demonstrated in normal and atherosclerotic treated specimens (23/24 or 96%) but not controls (0/4).(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon↗
PubMed1988

Spindle cell sarcoma of the heart in childhood: light microscopic, ultrastructural, and immunohistochemical evidence for smooth muscle, endothelial, and fibroblastic differentiation.

We describe the clinical presentation and pathological features of a cardiac sarcoma that occurred within the right atrial cavity of a 14-year-old boy. The patient presented with a 2-month history of increasingly severe heart failure. Tumor tissue obtained by biopsy showed light microscopic features of leiomyosarcoma. Immunohistochemical reactions and ultrastructural studies provided evidence of tumor cell differentiation along three cell lines--smooth muscle, fibroblastic, and endothelial--suggestive of origin from a multipotent subendothelial reserve cell. Postmortem examination disclosed a large necrotic tumor filling the right atrial chamber. Implants were present on the pericardium, but there were no other metastatic lesions. The difficulty of making a diagnosis of these rare neoplasms when the tumor is small and potentially curable results in a grim prognosis.

Adolescent↗