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Biomedical subjects

V M Walley

Publications and source records attributed to V M Walley.

At least 19 recordsLinked to original sources
PubMed1998

Evaluation of porcine valves prepared by dye-mediated photooxidation.

BACKGROUND: Previous studies demonstrated that dye-mediated photooxidation can stabilize bovine pericardium. Here, photooxidized porcine valve cusp and root tissue were assessed in comparison to fresh and glutaraldehyde-treated samples. METHODS AND RESULTS: In an in vitro tissue solubility test, both photooxidized and glutaraldehyde-treated tissues were resistant to protein extraction compared to fresh tissue. A rat subcutaneous model was used to test in vivo stability and calcification potential. In this study, four of the six fresh leaflets were not visible because of resorption while both photooxidized and glutaraldehyde-treated tissues were biostable. Mineral contents of the rat explants were much lower for both fresh and photooxidized leaflets when compared with glutaraldehyde-treated leaflets. Also, the aortic root calcified whether treated or not with the most mineral being associated with glutaraldehyde-treated root. Analysis of photooxidized porcine valves explanted from the mitral position in sheep indicated a material that was biostable and contained only minor calcification, perhaps due to deformed stents. CONCLUSIONS: Porcine valve tissue treated by dye-mediated photooxidation is biostable and resistant to calcification, and has potential for use in heart valve bioprostheses.

Animals↗
PubMed1998

Implantable cardioverter-defibrillators and the pathologist: comment and cautionary notes.

This paper briefly reviews the components of, the clinical uses of, the techniques to place, and the complications related to implantable cardioverter-defibrillators (ICDs). Information useful in the specific identification of ICDs is presented. A series of recommendations for the autopsy examination or postmortem explantation of ICDs by the pathologist is given. Because of the serious risk of injury to the pathologist possible with postmortem discharges of ICDs which have not been deactivated, and because of the risk of device explosion if the ICD is incinerated, a number of cautionary notes are provided. A brief case with occurrence of accidental postmortem discharge of an active ICD is also presented.

Accidents, Occupational↗
PubMed1997

Arterial expression of the plasminogen activator system early after cardiac transplantation.

OBJECTIVES: Recent studies suggest that alterations in tissue thrombolysis as well as the inward migration of cells may be specific events that contribute to coronary artery narrowing after cardiac transplantation. Plasminogen activators and inhibitors play a central role in governing not only tissue thrombolysis, but also vascular cell migration. The purpose of this study was to examine arterial wall expression of the plasminogen activation system in coronary arteries during graft vascular disease initiation and progression. METHODS: Using in situ hybridization and immunocytochemistry, the expression patterns of uPA and PAI-1 in coronary arteries from cardiac allografts were compared to those of young individuals without disease. RESULTS: Both PAI-1 and uPA were over-expressed early after transplantation and as late as 27 months post grafting. Over-expression of these molecules preceded morphological evidence of graft vascular disease. Of special note was the adventitial expression of uPA and PAI-1 in microvessels and myofibroblasts. In contrast, the expression of uPA and PAI-1 in normal coronary arteries was confined to endothelial cells of the central lumen, as well as low levels of expression in intimal and medial smooth muscle cells. CONCLUSIONS: Despite morphologic similarities between normal and transplant coronary arteries, differences were noted in the vascular expression pattern of uPA and PAI-1. The exact role of these molecules in graft vascular disease requires further study; however, it is intriguing to consider that a local imbalance in the plasminogen system may contribute to arterial wall thrombosis and/or excessive cell migration and the genesis of complex vascular lesions.

Adolescent↗
PubMed1997

The clinical and pathologic manifestations of iatrogenically produced mesothelium-rich fragments of operative debris.

OBJECTIVE: This report describes the clinical manifestations that may be associated with the amalgams of mesothelium and other debris which can be created iatrogenically when body cavities are opened or otherwise physically disturbed. METHODS: One autopsy and four surgical pathology cases are reviewed. Three of the studied patients had had recent cardiac surgery, one a laparotomy, and the fifth a thoracotomy. RESULTS: The series of five patients in this report demonstrates a wide range of manifestations when these tissue and debris amalgams are created. If the fragments gain an ingress to the vasculature, they may embolize and cause infarcts; if the origin of the amalgams is unappreciated, they may be confused with neoplasms; in other circumstances, the amalgams may represent incidental accompaniments of surgical specimens. CONCLUSION: Pathologists and clinicians should be aware of this recently described entity; only in the last couple of years has its pathogenesis been recognized. This report reviews an, until now, undescribed broad spectrum of clinical manifestations of these amalgams of iatrogenically created mesothelial and other operative debris.

Aged↗
PubMed1996

Cardiac transplantation after mechanical circulatory support: a Canadian perspective.

BACKGROUND: To assess the relative efficacy of cardiac transplantation after mechanical circulatory support with a variety of support systems, we analyzed our consecutive series of patients who had and did not have mechanical support before transplantation. METHODS: A review of 209 patients undergoing cardiac transplantation from 1984 to May 1995 was performed. Group 1 consisted of 110 patients who were maintained on oral medications while awaiting transplantation, and group 2 consisted of 60 patients who required intravenous inotropic support. Group 3 included 39 patients who had transplantation after mechanical circulatory support for cardiogenic shock. The indication for device implantation was acute onset of cardiogenic shock in 38 patients and deterioration while awaiting transplantation in 1 patient. The support systems were an intraaortic balloon pump in 13 (subgroup 3A), a ventricular assist device in 7 (subgroup 3B), and a total artificial heart in 19 patients (subgroup 3C). RESULTS: After transplantation, infection was more common in group 3 (56%) than in group 1 (28%) or group 2 (32%) (p = 0.005). Survival to discharge was lower for group 3 (71.7%) than for group 1 (90.9%) or 2 (88.3%) (p = 0.009). For mechanically supported patients, survival to discharge was 84.6% in subgroup 3A, 71.4% in subgroup 3B, and 63.1% in subgroup 3C (p = not significant). CONCLUSIONS: Transplantation after mechanical support offers acceptable results in this group of patients for whom the only alternative is certain death. Patient selection and perioperative management remain the challenge to improving these results.

Administration, Oral↗
PubMed1996

Contraction bands in visceral and vascular smooth muscle.

Smooth muscle contraction bands (SMCBs) have been described in the gastrointestinal tract, subsequent to acute ischemia, and in the coronary arteries of animals and individuals with a sudden death; in these circumstances SMCBs have been postulated to serve as a premortem marker, and suggested as diagnostically useful. The present investigation was undertaken to determine whether the presence of SMCBs could be correlated with a premortem clinical condition. Retrospectively, the routinely prepared histological sections from 76 autopsy and 93 surgical cases were screened semiquantitatively for the presence of SMCBs. The autopsy sections examined included the gastrointestinal tract, the prostate, and the coronary arteries, as well as all other smooth muscle-containing tissues; the surgical specimens included: coronary artery endarterectomies; saphenous vein bypass grafts; temporal artery biopsies; prostatic curettings; colectomies; varicose veins; leiomyomas of uterus, bowel, and skin; and, leiomyosarcomas. The clinical and pathology reports were reviewed for patient demographics, major clinical diagnoses, presence of shock, details of any resuscitation attempts, time interval to postmortem, and the cause of death. SMCBs were evident in 100% of the gastrointestinal and prostate, and in 96% of the coronary artery autopsy sections examined. All surgical specimens were positive for SMCBs, the exceptions being leiomyomas (positive in 13 of 22; 60%) and leiomyosarcomas (4 of 5; 80%); SMCBs in surgical specimens were less prominent when compared with those observed in autopsy tissue. No correlation was found between the presence of SMCBs and any clinical or demographic parameter assessed, because of the virtual universal occurrence of the SMCBs. The presence of less distinct SMCBs in surgical specimens may very well be artifactual, akin to myocardial and skeletal muscle contraction bands. The observation that SMCBs at autopsy are virtually ubiquitous suggests that they are best considered an agonal phenomenon, and a nonspecific pathological finding.

Adolescent↗
PubMed1996

Right heart failure due to ventricular adiposity: 'adipositas cordis'--an old diagnosis revisited.

Adiposity of the heart is characterized by an increase in the amount of epicardial and other adipose tissue. The most pronounced changes involve the right ventricle. The adipocytes may be interposed between myocytes, and in severe cases the normal mechanics and function of the ventricle are impaired. Adiposity of the heart is usually an incidental finding at autopsy, and only rarely is it of clinical significance. This report describes a 46-year-old female with multiorgan failure secondary to bronchopneumonia, purulent pericarditis, tamponade and sepsis, whose clinical course was altered due to severe adiposity of the heart, so-called 'adipositas cordis'.

Adipose Tissue↗
PubMed1996

Bacterial pericarditis after heart transplantation: successful management of two cases with catheter drainage and antibiotics.

OBJECTIVE: To describe the diagnosis and management of bacterial pericarditis after heart transplantation. PATIENTS AND METHODS: Two patients with Staphylococcus aureus pericarditis after heart transplantation were successfully treated conservatively with closed catheter drainage and antibiotics. RESULTS: The patients were alive three and six years, respectively, following surgery. At follow-up, right heart catheterization demonstrated normal hemodynamics in one patient and a pattern of constrictive pericarditis in the other patient which was man-aged with furosemide. CONCLUSIONS: Conservative management of bacterial pericarditis by closed catheter drainage and antibiotics can be considered in selected patients after heart transplantation.

Adult↗
PubMed1996

Coronary stenting in acute myocardial infarction--patency demonstrated postmortem.

This report describes a patient with an acute anterior myocardial infarction treated by primary angioplasty and stenting of the infarct-related artery. The patient died 48 h later and at postmortem examination, patency of the stented artery was demonstrated, despite the adverse conditions which preceded death.

Angioplasty, Balloon, Coronary↗
PubMed1995

Determinants of hospital survival after cardiac transplantation.

To identify the preoperative factors that influence hospital survival after transplantation we analyzed our consecutive experience of 183 transplantations in 179 patients over a 10-year period. There were 151 male and 29 female transplant recipients ranging in age from 10 days to 70 years (mean, 48 +/- 1 years). Diagnoses included coronary disease in 110 patients, cardiomyopathy in 55 patients, valvular disease in 6 patients, and congenital heart disease in 9 patients. Seventy-seven had undergone a previous cardiac operation, and 30 patients required preoperative mechanical support. Forty patients received hearts from donors who were 40 years old or older (range, 40 to 62 years). Ischemic time was greater than 240 minutes in 32 cases, and pulmonary vascular resistance was greater than 3 Wood units in 40 patients (range, 3.1 to 10.0 Wood units). Cyclosporine induction was used in 52 patients, whereas 128 recipients received polyclonal antibody prophylaxis. There were 25 hospital deaths. Recipient diagnosis, use of mechanical support, donor age, and the immune suppression protocol were related to hospital survival according to univariate analysis. Using multiple logistic regression, only the method of immune suppression induction and the use of mechanical assists were significant independent determinants of survival. In conclusion, we believe that extended ischemic times and donor age do not adversely affect the early success of transplantation, whereas induction with immune globulin may reduce early mortality. Patients requiring mechanical support before transplantation continue to be a challenge.

Adolescent↗
PubMed1995

Long-term experience with the Ionescu-Shiley pericardial valve.

To determine the long-term durability of the Ionescu-Shiley valve, we analyzed our experience with this valve at the University of Ottawa Heart Institute. To 1988, 780 patients have had aortic valve replacement (AVR = 528) or mitral valve replacement (MVR = 252). Of the aortic valves, 310 were standard profile and 218 were low profile. Of the mitral valves, 143 were standard profile and 109 were low profile. Actuarial survival at 10 years was as follows: AVR, 62% +/- 3%; MVR, 58% +/- 4%; p = 0.42. At 14 years, the results were AVR, 44% +/- 1% and MVR, 46% +/- 5%; p = 0.40. Reoperation was required in 197 patients. Structural failure was present in 85% of these valves, with leaflet tears alone in 69%, tears with calcification in 21%, and calcification alone in 10%. Leaflet tears occurred in 95% after AVR and in 78% after MVR (p = 0.006) and were seen in 95% of low-profile valves and 87% of standard-profile valves (p = 0.16). The actuarial freedom from reoperation at 10 years was: AVR, 58% +/- 3%; MVR, 62% +/- 5%; p = 0.49. At 13 years, these rates were 38% +/- 4% for AVR and 25% +/- 9% for MVR (p = 0.79). For AVR, the 10-year rate of freedom from reoperation was 57% +/- 4% for standard-profile valves and 57% +/- 8% for low-profile valves (p = 1.0). Similarly for MVR, the 10-year freedom from reoperation was 61% +/- 6% for standard-profile valves and 68% +/- 8% for low-profile valves.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1995

Comparative results with the St. Jude Medical and Medtronic Hall mechanical valves.

This study compared the clinical performance of the St. Jude Medical and Medtronic Hall mechanical valves in isolated aortic or mitral valve replacement. From 1984 to 1993, 349 St. Jude Medical valves (aortic 237, mitral 112) and 465 Medtronic Hall valves (aortic 272, mitral 193) were implanted in 814 patients at the University of Ottawa Heart Institute. The patients had similar preoperative characteristics. The hospital mortality rate for aortic valve replacement was 3.4% with the St. Jude Medical valve and 5.8% with the Medtronic Hall valve (p = 0.26) and the rate for mitral valve replacement was 8.9% with the St. Jude Medical valve and 11.9% with the Medtronic Hall valve (p = 0.54). Actuarial estimates of survival and freedom from complications were calculated. At 5 years the actuarial probability of survival (including hospital deaths) for aortic valve replacement was 86% +/- 3% with the St. Jude Medical valve and 68% +/- 4% with the Medtronic Hall valve (p = 0.0001) and for mitral valve replacement was 75% +/- 7% with the St. Jude Medical valve and 70% +/- 4% with the Medtronic Hall valve (p = 0.54). The most common cause of late death was cardiac failure and no deaths were caused by structural failure. The 5-year probability of freedom from bleeding after aortic valve replacement was 99% +/- 1% with the St. Jude Medical valve and 95% +/- 2% with the Medtronic Hall valve (p = 0.06) and after mitral valve replacement 99% +/- 1% with the St. Jude Medical valve and 97% +/- 2% with the Medtronic Hall valve (p = 0.37). The 5-year probability of freedom from thromboembolism after aortic valve replacement was 88% +/- 4% with the St. Jude Medical valve and 81% +/- 3% with the Medtronic Hall valve (p = 0.08) and after mitral valve replacement was 85% +/- 7% with the St. Jude Medical valve and 77% +/- 5% with the Medtronic Hall valve (p = 0.17). Reoperation was uncommon and there were no cases of structural valve failure. The 5-year actuarial estimate of freedom from reoperation therefore for aortic valve replacement was 99% +/- 1% with the St. Jude Medical valve and 96% +/- 2% with the Medtronic Hall valve (p = 0.09) and for mitral valve replacement was 98% +/- 2% with the St. Jude Medical valve and 95% +/- 3% with the Medtronic Hall valve (p = 0.40).(ABSTRACT TRUNCATED AT 400 WORDS)

Actuarial Analysis↗
PubMed1995

Potential cardiotoxicity with the use of DuP-941: a case report.

OBJECTIVE: To describe the clinical and pathological features of a patient with probable cardiotoxicity related to a newer chemotherapeutic agent, DuP-941. PATIENT AND METHODS: A 42-year-old woman with metastatic breast carcinoma treated with only DuP-941 developed, and died of, heart failure for which no other explanation was apparent. RESULTS: Clinically the patient's heart failure resembled that associated with anthracycline cardiotoxicity, as did the pathological features seen at autopsy. CONCLUSION: DuP-941 is a new chemotherapeutic drug that may supplant some uses of the anthracyclines because the former may have less cardiotoxicity. This report suggests that in some cases DuP-941 may have cardiotoxic effects as well.

Adult↗