Search PubMed⌕ Search

Biomedical subjects

T J Ryan

Publications and source records attributed to T J Ryan.

At least 127 records · Page 7Linked to original sources
PubMed1995

Significance of silent myocardial ischemia during exercise testing in women: report from the Coronary Artery Surgery Study.

To evaluate the significance of silent myocardial ischemia during exercise testing in women compared to men, we analyzed the data on 1087 women and 3834 men who underwent exercise testing and coronary angiography from the Coronary Artery Surgery Study (CASS) registry. The patients were divided into three groups on the basis of the results of exercise testing: group 1, silent ischemia (253 women, 853 men); group 2, symptomatic ischemia (156 women, 1250 men); and group 3, no ischemia (678 women, 1731 men). The survival rate at 12 years for women was 80% for group 1, 75% for group 2, and 86% for group 3 (p = 0.0022); the survival rate for men was 69% for group 1, 69% for group 2, and 76% for group 3 (p < 0.001). In both men and women with silent ischemia, the 12-year survival rate was related to the severity of coronary artery disease (CAD) and ranged from 79% for women with one-vessel CAD to 46% for men with three-vessel CAD. Survival at 12 years was enhanced by coronary artery bypass graft surgery as compared to medical treatment in patients with silent ischemia and three-vessel CAD for men (61% vs 46%, respectively, p = 0.0014) but not for women (45% vs 50%, respectively, p = 0.98). These data suggest that silent ischemia in women and men adversely affects survival rate and that men may gain more benefit from coronary artery bypass graft surgery than women when three-vessel CAD is present.

Cardiac Catheterization↗
PubMed1995

Right coronary artery stenosis: an independent predictor of atrial fibrillation after coronary artery bypass surgery.

OBJECTIVES: This study attempted to determine the importance of severe proximal right coronary artery disease as a predictor of atrial fibrillation in patients after coronary artery bypass surgery. BACKGROUND: Studies in patients undergoing noncardiac surgery have suggested that ischemia in the right coronary artery distribution is associated with a high incidence of atrial fibrillation. However, the importance of right coronary artery disease as a predictor of atrial fibrillation after bypass surgery is unknown. METHODS: The occurrence of sustained postoperative atrial fibrillation was studied prospectively in 168 consecutive patients undergoing coronary artery bypass grafting. Patients were followed up postoperatively until discharge. Severe right coronary artery stenosis was defined as > or = 70% lumen narrowing. RESULTS: Of 104 patients with proximal or mid right coronary artery stenosis, 45 (43%) had atrial fibrillation postoperatively compared with 12 (19%) of the 64 patients without significant right coronary disease (p = 0.001). Univariate predictors of atrial fibrillation included right coronary artery stenosis (p = 0.001), advancing age (p = 0.0001) and lack of beta-adrenergic blocking agent therapy after bypass surgery (p = 0.0004). Multivariate adjusted risk of developing atrial fibrillation after bypass surgery increased with the presence of severe right coronary artery disease (odds ratio 3.69, 95% confidence interval [CI] 1.61 to 8.48), advancing age (odds ratio 2.24/10 years, CI 1.48 to 3.41) and male gender (odds ratio 2.36, CI 1.01 to 5.49). The use of beta-blockers postoperatively was associated with a protective effect (odds ratio 0.4, CI 0.17 to 0.80). CONCLUSIONS: The presence of severe right coronary artery stenosis is an independent and powerful predictor of atrial fibrillation after coronary artery bypass surgery. In association with age, gender and postoperative beta-blocker therapy, these variables can be used to identify patients at increased risk for developing this arrhythmia.

Aged↗
PubMed1995

Guidelines for training in adult cardiovascular medicine. Core Cardiology Training Symposium (COCATS). Task Force 7: training in cardiovascular research.

It is vital to the future intellectual health of cardiovascular medicine and the welfare of patients with cardiovascular disease that all future cardiologists be familiar with the principles and tools of research. Training in research requires the intense involvement of productive and established investigators. Those trainees preparing for a career in investigative cardiology require a carefully developed but flexible educational plan that will permit them to be successful in their research careers over an extended period.

Adult↗
PubMed1995

Coronary angioplasty versus bypass grafting. Cost-benefit considerations.

Both PTCA and CABG are effective strategies for coronary revascularization. The initial cost of PTCA is 60% to 75% less than that of CABG. PTCA patients, however, often require repeat procedures secondary to restenosis and incomplete revascularization. Despite this, the cost of PTCA is still approximately half that of CABG at 1 year but approaches that of CABG at 3 years. The BARI SEQOL trial will be available in 1996 and will analyze cost differences as well as quality of life for PTCA versus CABG up to 5 years after revascularization. Patients with single-vessel disease can be treated effectively with PTCA or medications. Although PTCA is more expensive, patients have less angina and better exercise tolerance. Many patients with single-vessel disease are now treated with PTCA, who in the past would have been treated medically. Undoubtedly, this change has added to the increasing cost of health care. Although certain patient groups, such as those with three-vessel disease and low ejection fraction and left-main disease, have a significant mortality advantage when revascularized surgically, many patients with symptomatic two-vessel and three-vessel disease can be treated either with CABG or PTCA with no difference in mortality and MI. To reach this equivalent outcome, however, PTCA patients require more interventional procedures. As a result, at 3 years, there is no cost savings with PTCA. Physicians in the United States have been able to choose the mode of revascularization for patients based on clinical judgment and preference, which has been financed by third-party payers. Given the escalating costs of health care in a country with limited resources, physicians failing to consider costs and benefits may find their choices limited secondary to lack of funding and restrictive policies. Future treatment of CAD will most likely be influenced by aggressive lipid-lowering therapy to prevent secondary cardiac events and possibly by gene therapy to prevent restenosis.

Angioplasty, Balloon, Coronary↗
PubMed1995

The epidemiology of Mycobacterium bovis infection in brushtail possums (Trichosurus vulpecula Kerr) in the Hauhungaroa Ranges, New Zealand.

The prevalence of Mycobacterium bovis infection in the wild possum population around the perimeter of the Hauhungaroa Ranges, New Zealand, was determined by a cross-sectional study, and risk factors associated with tuberculosis were identified. Of 6083 possums necropsied, 128 (2.1%) showed gross lesions suggestive of tuberculosis infection, and 76 (1.25%) were subsequently confirmed as tuberculous on histopathological examination. Considering only traplines where tuberculosis was detected, adult possums were 1.9 times as likely to be infected as immature animals, and the total prevalence was 5.4% in males compared with 3.9% in females. Adult females were 3.64 times as likely to be infected as immature females, whereas there was no significant age difference for males (odds ratio = 1.46, p=O.29). Immature males were 3.12 times as likely to be infected as immature females. Possums in poor condition were more likely to be found infected than possums in good condition. Tuberculous possums were found in 27 local clusters of infection. The correlation between the prevalence of tuberculosis in possums in zones and the incidence of tuberculosis in cattle on adjoining properties was 0.4 (p<O.05).

Journal Article↗
PubMed1994

Right ventricular infarction.

Right ventricular infarction complicates up to half of inferior left ventricular infarctions. The term represents a spectrum of disease from mild, asymptomatic right ventricular dysfunction to cardiogenic shock, and it includes transient ischemic myocardial dysfunction as well as myocardial necrosis. Right ventricular infarction is associated with considerable morbidity and mortality, and its presence defines a high-risk subgroup of patients with inferior left ventricular infarction. Diagnosis of this condition requires a high degree of suspicion based on clinical findings and the early recording of the electrocardiogram through right precordial leads, as well as elevated right-sided filling pressures out of proportion to left-sided filling pressures. The proper management of right ventricular infarction requires sustaining adequate right ventricular preload with volume loading and maintenance of atrioventricular synchrony, reduction of right ventricular afterload (particularly when left ventricular dysfunction is present), and inotropic support of the right ventricle. Early reperfusion with fibrinolytic therapy or direct angioplasty is also warranted. Survivors of right ventricular infarction generally have a restoration of normal right ventricular function with resolution of hemodynamic abnormalities.

Echocardiography↗
PubMed1994

Proteolytic enzymes in wound healing: the role of enzymatic debridement.

Proteolytic enzymes are a family of proteins that serve to degrade necrotic debris derived from cell breakdown. They are produced endogenously often as precursor proteins whose activation is precisely regulated. These activated enzymes serve many functions in normal as well as pathological situations. In particular they are involved in the regulation of cell maturation and multiplication; collagen synthesis and turnover; the development and removal of the perivascular fibrin cuffs found in venous insufficiency and leg ulceration as well as the removal of dead tissues following inflammation. As a limited number of enzymes perform all these functions, it is difficult to predict the effects of applying synthetic proteolytic enzymes to a wound. Many such enzymes are currently commercially available and being promoted as alternatives to surgical wound debridement. It is important for their use to be considered in the context of their interaction with endogenous proteases, their physiological role in tissue, their ability to reach a desired target and the stage of wound healing at the time they are applied.

Cell Division↗
PubMed1994

Differences in compensatory vessel enlargement, not intimal formation, account for restenosis after angioplasty in the hypercholesterolemic rabbit model.

BACKGROUND: In de novo human atherosclerosis, compensatory vessel enlargement limits the effect of intimal plaque formation on lumen narrowing. We hypothesized that arterial remodeling may also play an important role in determining the chronic lumen size after angioplasty and tested this hypothesis using the hypercholesterolemic rabbit iliac artery angioplasty model. METHODS AND RESULTS: Morphometric analysis of histological cross-sectional areas of vessels from animals killed immediately after angioplasty (acute group, n = 11) were compared with the same areas from animals killed 4 weeks after the procedure (chronic group, n = 37), when restenosis occurs in this model. The area circumscribed by the internal elastic lamina (IEL) increased by 20% from acute to 4 week follow-up after angioplasty (acute group, 2.36 +/- 0.45 mm2, chronic group, 2.84 +/- 0.89 mm2). Over the same time period, intimal area increased by 0.82 mm2. Despite this increase in intimal area, lumen area decreased by only 0.34 mm2 because of the compensatory enlargement of the IEL area. In the chronic group, polynomial regression analysis revealed a quadratic relation between intimal area and lumen area (R2 = .35, P < .001). A lumen area of 0.45 mm2 (the nadir of the quadratic relation) was used to divide the chronic group into two subgroups: restenotic (n = 21; lumen area, < 0.45 mm2) and nonrestenotic (n = 16; lumen area, > 0.45 mm2). By definition, there was a significant difference in lumen area between the two subgroups (0.15 +/- 0.15 mm2 for restenotic; 0.73 +/- 0.18 mm2 for nonrestenotic). Surprisingly, the intimal areas in the two subgroups were virtually identical (2.41 +/- 0.92 mm2 for restenotic, 2.49 +/- 0.69 mm2 for nonrestenotic, P = NS). The difference in the lumen area between restenotic and nonrestenotic vessels was a result of the significantly greater IEL area in the nonrestenotic subgroup (3.22 +/- 0.83 mm2 for nonrestenotic, 2.56 +/- 0.84 mm2 for restenotic, P < .05). In both restenotic and nonrestenotic vessels, the IEL area increased with increases in intimal area. In the restenotic arteries, the slope of this correlation was < 1, showing inadequate compensatory enlargement for the intimal plaque. In the nonrestenotic vessels, the slope was > 1, limiting the effect of intimal plaque on luminal narrowing. CONCLUSIONS: These data indicate that the iliac artery in an atherosclerotic rabbit model compensates for intimal formation after angioplasty by vessel enlargement. Furthermore, the degree of vessel enlargement is more important than intimal area in determining the chronic lumen size.

Angioplasty, Balloon↗
PubMed1994

United Nations and nongovernmental organizations. Healthy skin for all.

The International League of Dermatologic Societies, the International Foundation for Dermatology, and the International Society of Dermatology: Tropical, Ecological, and Geographic, are the leading nongovernmental dermatology organizations that communicate with United Nations agencies such as the World Health Organization and UNESCO. The common goal of health for all must include healthy skin for all, and it therefore must include concepts such as primary health care, disability, wound healing, and advancement of women as well as the control and elimination of specific diseases such as leprosy.

Dermatology↗