Biomedical subjects
Publications and source records attributed to V M Walley.
The pathologic findings in two low-profile Ionescu-Shiley bioprostheses that failed because of cusp tears are presented. Both valves were in the mitral position, one in place 28 months and the other 40 months. Observation of the valves and their tears suggests that stress at the cusp alignment stitches may be important in the genesis of the tears.
The experience of the University of Ottawa Heart Institute with valvular replacement by Ionescu-Shiley bovine pericardial bioprostheses has been recently reviewed. The focus of the present study is to examine the patterns of valve failure in a subgroup of these prostheses, those that required explanation for valve failure caused specifically by cusp wear and tears. A total of 22 aortic and six mitral standard-profile valves failed in this way. Twenty-five of these valves were reassessed and are the subject of this paper. Twenty-eight holes and 56 cusp tears occurred in these valves in locations which, along with coexistent pathologic findings, suggested that the cusp commissural suture/alignment stitch was the point of their origin. The importance of this observation and postulation about the genesis of these cases of valve failure lies in the potential for improvement of this valve's performance by modifications of its manufacture.
A 61-year-old World War II fighter pilot sustained a gunshot injury to the right fibula and an arteriovenous fistula subsequently developed. Angiographic examination 44 years later for evaluation of an abdominal aortic aneurysm showed an unusually shaped aneurysm and the right arteriovenous fistula with antegrade dilation of the ipsilateral arterial system in continuity with the aneurysm. We hypothesize that this arteriovenous fistula, which involved the peroneal and anterior tibial arteries of the right leg of 44 years' duration, was responsible for the development of this man's abdominal aortic aneurysm.
In cardiac procedures that use access to the right atrium, the coronary sinus is at risk of accidental trauma and subsequent thrombosis as demonstrated by the two cases reported in this paper. The thromboses occurred in the setting of right heart failure and after procedures that involved catheterization or cannulation of the right atrium. A review of the literature revealed only rare instances of this complication, but, with the increasing use of the right atrium and coronary sinus for diagnostic and therapeutic purposes, injury to the coronary sinus must be considered.
Laser angioplasty has been limited by the lack of precise control of thermal and acoustic vascular injury. Pulsed excimer lasers, by contrast, have a capacity to affect target tissue without heat dispersion or damage to surrounding structures. The ablative properties of three excimer wavelengths, krypton fluoride (249 nm), xenon chloride (308 nm), and xenon fluoride (351 nm), were investigated with the use of fresh human cadaveric normal and atherosclerotic femoral arteries. Light and electron microscopy demonstrated clean cuts with histologically normal edges. There was no evidence of either thermal or acoustic damage with any of the wavelengths studied. The depth of ablation varied directly with the number of pulses and inversely with tissue density while the incision width remained constant. The excimer laser appears to offer significant advantages over its conventional counterparts for the ablation of atherosclerotic plaque.
A large gastric arteriovenous malformation was an incidental finding at autopsy in a 74-year-old man. Gastric arteriovenous malformations are themselves unusual, and this one was even more so, as there were massive deposits of amyloid in the walls of the constituent vessels. The nature of the amyloid was confirmed by histochemical and electron microscopic techniques. This appears to be an unusual form of localized amyloidosis.
To determine the clinical, hemodynamic and pathological features that contribute to major cardiac complications after vascular surgery, six patients with early postoperative cardiogenic shock (group 1) were analysed retrospectively and compared to nine patients without complications (group 2) who were carefully analysed prospectively. Four group 1 patients had elective repair of an abdominal aortic aneurysm, one had repair of a false iliac artery aneurysm and one had a femoropopliteal graft inserted. Four group 2 patients had elective repair of an abdominal aortic aneurysm and five had aortobifemoral reconstruction. The Goldman multifactorial index was similar in both groups and indicated an expected death rate of 2% and a morbidity rate of 5%. In group 1, the earliest sign of cardiovascular compromise was an elevated pulmonary wedge pressure during operation. Postoperatively, electrocardiographic evidence of myocardial ischemia was present in all six patients and preceded cardiogenic shock. Autopsy of the four patients who died demonstrated triple-vessel disease in all but recent occlusion in only one patient. There was evidence of extensive subendocardial infarction in all four. Angiography of the two survivors in group 1 also demonstrated triple-vessel disease. The authors conclude that by using ordinary clinical methods it is difficult to identify patients likely to have major complications postoperatively. Elevated pulmonary wedge pressures or electrocardiographic evidence of myocardial ischemia may be early warning signs of impending cardiac catastrophe and should be treated aggressively. The underlying pathophysiology appears to be perioperative stress in a setting of severe triple-vessel coronary artery disease.
A case in which unusually large deposits of Tamm-Horsfall protein were identified in perinephric adipose tissue is presented. The deposition around the kidney in this case was most likely due to calyceal rupture, secondary to distal ureteric obstruction. The peculiar gross and microscopic appearance of these deposits, their intense staining with the periodic acid--Schiff technique, and their association microscopically with epithelial fragments raised the possibility of infiltration by mucin-producing adenocarcinoma. The localization of Tamm-Horsfall protein in the deposits by the immunoperoxidase technique helped to confirm their true nature.
We describe a baby with external and internal anomalies of the Majewski form of the short rib-polydactyly (SRP) syndromes. Previously unreported abnormal vertebral bodies, delayed ossification of the sternum and fibulae, and a diencephalic hamartoma are noted. These abnormalities and minimal histologic abnormality at the chondro-osseous junction suggest that this syndrome may be heterogeneous or more variable than previously known.
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Heparin-associated thrombocytopenia with thrombosis is a rare but serious complication in patients receiving heparin therapy. We report a case of a patient with this complication who had massive thrombosis within the descending thoracic aorta detected by transesophageal echocardiography. Our case suggests that a transesophageal echocardiographic examination can be useful in the early diagnosis of heparin-associated thrombocytopenia and thrombosis.
An unusual case of mitral annular calcification presenting as a left atrial mass is discussed. The differential diagnosis of left atrial masses with particular reference to their echocardiographic features is reviewed.
Histologic estimation of coronary artery stenoses (CAS) provides the 'gold-standard' for clinicopathologic correlations and medicolegal investigations, yet little evidence supports histology as a reproducible diagnostic measure, and none addresses the effect of training on its use. To study these questions, 20 randomly selected Movat-stained coronary artery cross-sections were reviewed 3 times, at 3-month intervals, by six clinical pathologists (CPs), six pathology residents (Res), seven anatomic pathologists (APs), and two cardiovascular pathologists (CVPs). Before the third iteration, a guide to CAS assessment with illustrations was provided. Inter- and intraobserver reproducibility were determined using interclass correlation coefficients (ICC) (0.40-0.75 = fair-good; > or = 0.76 = excellent agreement beyond chance). Surprisingly, all study groups had excellent interobserver reproducibility. Before training, at Time 1, the scores were CPs, 0.77; Res, 0.89; APs, 0.93; and CVPs, 0.93. After training, at Time 3, the results were CPs, 0.81; Res, 0.91; APs, 0.86; and CVPs, 0.88. Intraobserver reproducibility for CPs overall was good (ICC, 0.74), and excellent for Res, APs, and CVPs (0.89, 0.94, and 0.97, respectively). In conclusion, statistical analysis failed to demonstrate any significant effect of training or experience on observer reproducibility.
The authors have recently investigated the histologic estimation of coronary artery stenoses (CAS) to determine its reproducibility and the effect of training on reproducibility. The present study extends this work, examining the accuracy, the sensitivity, and the specificity of the estimation of CAS. Further, the effect of one histologic variable (i.e., arterial lumen shape) on the evaluation of CAS is examined. As described previously, 20 randomly selected Movat-stained coronary artery cross-sections were reviewed three times, at 3-month intervals, by six clinical pathologists (CPs), six pathology residents (Res), seven anatomic pathologists (APs), and two cardiovascular pathologists (CVPs). Before the third iteration, training in CAS assessment was provided. In the present study, for comparison with observer estimates, image analysis was used to establish the actual percent CAS and determine observer accuracy. The results of this study showed, paradoxically, that greater experience did not correlate with greater accuracy: The CPs consistently had the highest accuracy scores and the CVPs consistently had the lowest. Training, however, improved the accuracy scores of all groups. Stenotic arterial cross-sections with residual lumens showing concentric or eccentric polymorphous shapes were consistently underestimated compared to image analysis, while lumens with a eccentric slitlike shape were consistently overestimated.
This article describes a 42-year-old male patient with a longstanding history of insulin-dependent diabetes mellitus, systemic arterial hypertension, and chronic renal failure. The patient had severe mitral annular calcification (MAC) identified at autopsy. This MAC was of an amorphous, caseous-appearing type; it displaced the posterior mitral valve leaflet and extruded into the myocardium of the lateral and posterolateral left ventricle to involve the epicardial surface. The MAC produced extramural erosion of the wall, and dissection into the media, of the first left/obtuse marginal coronary artery. This coronary artery involvement by, and other complications of, MAC are discussed.
BACKGROUND: Despite the increasing use of stents, few reports have described human coronary artery morphology early and late after stenting. METHODS AND RESULTS: Histology was performed on 55 stents in 35 coronary vessels (32 native arteries and 3 vein grafts) from 32 patients. The mean duration of stent placement was 39+/-82 days. Fibrin, platelets, and neutrophils were associated with stent struts </=11 days after deployment. In stents implanted for </=3 days, only 3% of struts in contact with fibrous plaque had >20 associated inflammatory cells compared with 44% of struts embedded in a lipid core and 36% of struts in contact with damaged media (P<0.001). Neointimal growth determined late histological success, and increased neointimal growth correlated with increased stent size relative to the proximal reference lumen area. Neointimal thickness was greater for struts associated with medial damage than struts in contact with plaque (P<0.0001) or intact media (P<0.0001). When matched for time since treatment, neointimal cell density in stented arteries was similar to that in unstented arteries that had undergone balloon angioplasty and showed similar proteoglycan deposition. CONCLUSIONS: Morphology after coronary stenting demonstrates early thrombus formation and acute inflammation followed by neointimal growth. Medial injury and lipid core penetration by struts result in increased inflammation. Neointima increases as the ratio of stent area to reference lumen area increases. Deployment strategies that reduce medial damage and avoid stent oversizing may lower the frequency of in-stent restenosis.
It is now apparent that light microscopy and histochemistry failed to identify correctly the nature and composition of pigments in various gastrointestinal tract melanoses. In most instances it was thought that the pigment was melanin or a melanin-like substance. Electron microscopy (EM) and electron-probe energy dispersive x-ray analysis have rectified these errors and have shown the following: in melanosis coli the pigment granules contain lipofuscin; in melanoses ilei the pigment granules may contain either silicates and titanium or hemosiderin; and in melanosis duodeni the pigment granules contain iron sulfide. In melanosis esophagi it is not clear what the pigment is; it could be melanin or lipofuscin.