Biomedical subjects
Publications and source records attributed to B F Waller.
Six patients undergoing aortic valve replacement had rare or unusual causes of isolated, pure aortic regurgitation. Two patients had congenitally bicuspid aortic valves with a false commissure (raphe) displaced to the aortic wall ("tethered bicuspid aortic valve"), two had floppy aortic valves, one had a congenital quadricuspid valve, and one had radiation-induced valve damage.
This report provides the anatomic basis for catheter balloon valvuloplasty procedures. The morphologic hallmark of mitral stenosis is commissural fusion and the major mechanism of successful balloon valvuloplasty is commissural splitting. Single and double dilating balloons are used to increase the cross-sectional orifice area of stenotic mitral valves. Double balloons appear to improve the luminal diameter and cross-sectional area compared with single balloons. This report also illustrates the anatomic basis for single and double balloon catheter placement and position using the transseptal approach.
Recent developments have taken place in the diagnosis of cardiovascular disorders in the area of cardiac imaging techniques. From a previous era of imaging by silhouettes (chest roentgenography, fluoroscopy, angiocardiography), we have emerged into an era of imaging by tomographic scanning (echocardiography, radionuclide tomography, computed tomography, magnetic resonance). A basic understanding of tomographic cardiac anatomy is the foundation for proper use and interpretation of these new imaging modalities. The present report provides a description of the techniques of tomographic cutting of necropsy cardiac specimens and illustrates some of the pathologic cardiac abnormalities cut in these tomographic planes. Part I of this report describes position of the heart and tomographic axis planes, preparation of the heart and methods of cutting at necropsy, and the short-axis, two-chamber, and four-chamber views of the heart.
Recent developments have enhanced the diagnosis of cardiovascular disorders in the area of cardiac imaging techniques. From an era of imaging by silhouettes (chest roentgenography, fluoroscopy, angiocardiography), we have emerged into an era of imaging by tomographic scanning (echocardiography, radionuclide tomography, computed tomography, magnetic resonance). A basic understanding of tomographic cardiac anatomy is the foundation for proper use and interpretation of these new imaging modalities. The present report provides a description of the techniques of tomographic cutting of necropsy cardiac specimens and illustrates some of the pathologic cardiac abnormalities cut in these tomographic planes. Part II of this report describes the long-axis method, methods using the body rather than the heart as the reference axis, and includes transverse, frontal, and parasagittal methods of imaging the heart.
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Double balloon percutaneous transluminal aortic valvuloplasty (PTAV) was performed on 149 patients (76 male (51%), mean age 76 +/- 11 years) whose symptoms included severe congestive heart failure in 127 cases (82%), syncope in 21 (14%) and angina in six (4%). Significant changes (P less than 0.05) in peak systolic (83 +/- 36 to 38 +/- 30 mmHg) and mean gradient (68 +/- 25 to 36 +/- 21 mmHg), and aortic valve area (0.6 +/- 0.2 to 1.0 +/- 0.4 cm2) were achieved in 130/149 patients (87%). Complications included an overall in-hospital mortality of 13%, (10.0% excluding the six deaths occurring in 18 moribund patients), a neurologic deficit incidence of 3%, and surgical arterial entry site repair 3.0% (14/47) of patients. Multivariate analysis identified congestive heart failure (NYHA Class IV), left ventricular ejection fraction, cardiac output and coronary artery disease as independent variables significantly affecting in-hospital mortality. Predictors of poor long-term survival were degree of heart failure, and coronary artery disease. The cumulative probability of survival at 24 months was 52 +/- 5% (excluding non-cardiac deaths, was 66 +/- 3%). Follow-up (mean time: 16 +/- 7 months) of 130 patients discharged alive revealed 41 late deaths (26 cardiac related). Sixty-two patients (70%) were symptomatically improved; 17 patients had symptom recurrence and underwent repeat valvuloplasty, and 10 patients valve replacement. Follow-up catheterization of 18 asymptomatic patients revealed that 11 patients had silently restenosed. These data indicate that aortic valvuloplasty is a palliative therapy for elderly patients, who are poor surgical candidates, with symptomatic calcific aortic stenosis with reasonable clinical success and long-term survival when considering their clinical status, but with a significant restenosis rate.
In 1985, we began studying athletic fatalities in Marion County, Indiana (city of Indianapolis, population 779,966) U.S.A. We previously reported the data for calendar year 1985. The reviewed cases include all sudden, unexpected, or traumatic deaths of conditioned, competitive athletes in Marion County. This follow-up is a review of all athletic fatalities in Marion County that occurred from January 1986 through July 1988. All deaths during or immediately after athletic activity were reviewed, whether or not the participant was a conditioned athlete. Natural disease, especially heart disease without prior diagnosis, continues to be the most prevalent modality of death.
Previous studies have established the feasibility of combining tissue heat generated by radio-frequency (RF) current and mechanical pressure to manage problems of percutaneous transluminal angioplasty (PTA) that are thought to cause postangioplasty restenosis (PARS). In the current in vitro study of normal and atherosclerotic human aortic layers (intima-media and media-adventitia) separated artificially, the purposes were to identify a dose-response relationship between the total RF energy delivered and the resultant weld strength between vascular tissues and to study the histologic correlates. Twenty-eight control and 100 experimental specimens were evaluated. The mean weld strength for all specimens with no RF current (at 0 J) was 4.1 g +/- 2.0; at 100 J, 5.9 g +/- 2.8; at 200 J, 28.5 g +/- 3.3; at 300 J, 50.0 g +/- 5.5; and at 500 J, 82.0 g +/- 8.2. Inspection of treated specimens revealed vascular molding (depression in the surface corresponding in dimensions to those of the electrode gap in the treatment chamber). Histologic examination revealed necrosis in the region underlying the electrode gap, a hypocellular fusion zone, indistinct boundaries between welded specimen parts, and transition zones to normal histologic characteristics at either end of each specimen. RF energy combined with mechanical pressure produces dose-dependent thermal welds in artificially dissected vascular tissues, molding of vascular tissue, and cellular destruction in the media. These findings may have clinical application in the management or prevention of all forms of PARS in humans and in the treatment of spontaneous aortic dissection.
Despite widespread use of coronary balloon angioplasty, advances in angioplasty technology, and improvements in operator technique, restenosis at the angioplasty site is the major problem limiting the long-term efficacy of this procedure. The article reviews morphologic-histologic observations at angioplasty restenosis sites, speculates about the connection between the acute injury patterns of balloon angioplasty and the development of restenosis, and briefly reviews the currently understood pathways to restenosis and possible approaches to its reduction or elimination.
Surgical resection of a cardiac myxoma was performed in 14 patients at the Indiana Heart Institute at St. Vincent Hospital and Health Care Center in Indianapolis from 1974 to 1989. Thirteen were located in the left atrium and one in the right atrium. The 10 women and four men ranged in ages from 28 to 75 years. Surgical complications included one perioperative death, one late death and one late recurrence requiring reoperation. Physicians must be highly suspicious to correctly diagnose this unusual but surgically correctable entity. Two-dimensional echocardiography is the diagnostic technique of choice for both early diagnosis of a cardiac myxoma and late follow-up after resection.
Cardiovascular disease continues to be the single most common generic cause of sudden and unexpected deaths. Atherosclerotic coronary heart disease and acute myocardial infarction are the most prevalent forms of fatal cardiac disease observed at autopsy. Other cardiac lesions are frequently listed as causes of death, but the prevalence of such lesions as incidental findings in the general population is unknown. In this study, 470 consecutive forensic autopsies were evaluated for minor and major anomalies. The most frequently observed major congenital finding was floppy mitral valve (5%). Tunneled coronary arteries, considered minor congenital findings, were seen in 29%. Atherosclerotic coronary heart disease was the most common major acquired finding, observed in 16% of cases. Of the 470 hearts, only 8% were considered normal.
Five hundred consecutive coronary artery segments histologically narrowed 76 to 95% in cross-sectional area by atherosclerotic plaque were classified into concentric and eccentric luminal types. Of the 500 segments, 365 (73%) were eccentric and 185 (27%) were concentric. Of the eccentric lesions, an arc of disease-free wall accounted for 2.3 to 32% (mean 16.6%) of the circumference of the internal elastic membrane. The average thickness of the coronary artery media was thinner in diseased segments (mean 88.4 micron) compared to disease-free wall segments in the same vessel (mean 202.9 micron). The presence of disease-free wall segments has clinical importance in at least three areas: (1) the accuracy with which angiography reflects the morphologic features of the diseased vessel, (2) coronary artery spasm, and (3) the mechanism of coronary balloon angioplasty and subsequent "restenosis" of previously dilated vessels.
Cardiac manifestations of secondary tumors of the heart may exert their effects directly by endocardial, myocardial, epicardial, or cavitary deposits (metastatic lesions), indirectly via tumor products such as in carcinoma, or mediated by therapy (chemotherapy, radiation) to treat the primary neoplasm. Part I of this review summarizes the frequency of metastatic cardiac involvement by various tumors and discusses pericardial manifestations (effusion, tamponade, constriction), one of the most common consequences of direct cardiac involvement by secondary tumors.
Cardiac manifestations of secondary tumors of the heart exert their effects directly by endocardial, myocardial, epicardial or cavitary deposits (metastatic lesions); indirectly via tumor products such as carcinoma; or mediated by therapy (chemotherapy, radiation) to treat the primary neoplasm. Part II of this review summarizes certain direct effects of noncardiac tumors on the heart including superior and inferior vena cava syndromes, pulmonary artery and vein obstruction or compression, myocardial implants, and intracavitary metastases. Many of these direct effects may be noninvasively diagnosed by computed tomography, magnetic resonance imaging and/or two-dimensional echocardiography.
Abrupt reclosure of atherosclerotic vessels after percutaneous transluminal balloon angioplasty has been blamed on traumatic dissections and elastic recoil of the vessel wall. Thermal energy with compression produces fusion of separated arterial wall layers, and heat appears to alter the elastic recoil of the vessel wall. Radiofrequency (RF) thermal energy has been used to perform vascular anastomoses and thermal angioplasty. A simple in vivo experiment was designed to describe and quantitate vascular tissue weld strength produced by a range of RF thermal energy levels. Canine carotid arteries were compressed between a pair of modified bipolar forceps that applied RF energy, causing occlusive tissue welds between the apposed intimal surfaces. The strength of the welds was evaluated by measuring the perfusion pressure required to reopen the vessel lumen. A dosimetry range of 0 to 205 joules showed a typical dose-response curve for the relationship between energy applied and bond strength, plateauing at approximately 300 mm Hg. Light microscopy showed fusion of the inner surfaces of the vessel with preservation of vessel wall architecture. Additionally inflation of a bipolar RF balloon catheter in the normal canine carotid lumen produced an alteration of vessel profile angiographically and histologically. Results of these preliminary experiments suggest that balloon angioplasty with adjunctive RF thermal energy may have benefits in reducing the factors causing acute failure of conventional percutaneous transluminal balloon angioplasty.
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The complexity and cost of cardiovascular medical care dictate research to deliver high quality and cost-conscious cardiovascular care. This goal is aided by modeling medical decision making. To be useful, the modeling must be based on real data so that the results can serve as a guide to actual practice. It is suggested that a registry of randomized clinical trials and larger data bases in cardiovascular disease and health care delivery be established. The registry would be a resource for those desiring to model decision making. The registry would contain key words allowing retrieval by modelers accessing the registry and would contain contact information for consideration of possible collaborative work. The initiation of such a registry should contain plans for its evaluation to determine whether the registry itself is a cost-effective tool to encourage the needed research.
Although various public health preventive efforts and prescribed pharmacologic treatment methods will have long-term benefits in the reduction of coronary artery atherosclerosis and subsequent cardiac events, the immediate and short-term future in the treatment of coronary artery disease will focus on several interventional devices designed to remodel or remove causes of acute and chronic coronary artery obstruction. Certain clinical-morphologic aspects of these interventional devices or techniques that result in remodeling of the coronary lumen shape (balloon angioplasty, thermal probes, intravascular stents) or removal of obstructing material (lasers, atherectomy devices) are reviewed. Two new areas in the pathology of atherosclerotic plaque (plaque fissures, eccentric plaque) and their clinical relevance in coronary heart disease are described.