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Biomedical subjects

D Waters

Publications and source records attributed to D Waters.

At least 127 records · Page 7Linked to original sources
PubMed1992

Successful treatment of severe heart failure caused by idiopathic giant cell myocarditis.

A 53-year-old woman presented with increasing dyspnea over one month and signs of severe heart failure. A right ventricular biopsy revealed giant cell myocarditis. She was treated with a combination of cyclosporine, imuran and prednisone and improved dramatically--left ventricular ejection fraction increased from 13 to 66%. That such a response is possible has important implications with respect to both the etiology and treatment of this rare disorder.

Autoimmune Diseases↗
PubMed1992

Interventions that beneficially influence the evolution of coronary atherosclerosis. The case for calcium channel blockers.

Calcium channel blockers have been shown to retard the development of atherosclerosis in rabbits fed cholesterol-rich diets. The mechanism accounting for this effect is controversial but may be by stimulation of cholesteryl ester hydrolase activity in smooth muscle cells, by amelioration of hypercholesterolemia-induced endothelial dysfunction, or by inhibition of smooth muscle cell proliferation and migration. The effect of calcium channel blockers on the evolution of coronary atherosclerosis in humans has been assessed in two clinical trials. In the Montreal Heart Institute trial, nicardipine did not influence the overall rate of progression and regression; however, nicardipine-treated patients experienced significantly less progression of minimal lesions, defined as stenoses of < or = 20% severity. In the International Nifedipine Trial on Antiatherosclerotic Therapy, nifedipine had no effect on overall progression and regression but reduced the rate of appearance of new coronary lesions. These studies constitute a potentially important new approach to the management of coronary atherosclerosis.

Animals↗
PubMed1992

Syncope: a symptom of coronary artery spasm after cardiac transplantation.

Two cases of coronary spasm in cardiac transplant recipients in which the presenting symptom was syncope without chest pain are reported. Diagnosing coronary spasm in transplant patients appears to be important because, based upon the few cases in the literature, prognosis is very poor. Coronary spasm may be related to accelerated atherosclerosis occurring in the transplanted heart.

Coronary Artery Disease↗
PubMed1991

Newer concepts in the treatment of unstable angina pectoris.

Unstable angina patients should be hospitalized and treated with antianginal drugs to control their symptoms and with aspirin or heparin to reduce the risk of myocardial infarction. Heparin is probably preferable to aspirin acutely, because it also reduces the risk of refractory angina. However, aspirin therapy should be started before heparin is discontinued, to prevent the rebound in symptoms, and continued long-term. Unless specifically contraindicated, coronary arteriography should be performed to identify patients who might benefit from coronary bypass surgery or angioplasty. Control of risk factors is important for long-term outcome.

Angina, Unstable↗
PubMed1991

Regression of coronary atherosclerosis: an achievable goal? Review of results from recent clinical trials.

During the past decade, large, placebo-controlled, randomized trials have demonstrated that the incidence of coronary events can be reduced by treating hyperlipidemia. In studies with angiographic end points, marked lowering of total and low-density-lipoprotein cholesterol with comparable increases in high-density-lipoprotein cholesterol retards the progression of coronary atherosclerosis and favors regression. In the Cholesterol-Lowering Atherosclerosis Study (CLAS), such therapy also prevented the appearance and worsening of atherosclerotic lesions in coronary bypass grafts. In the recently reported Familial Atherosclerosis Treatment Study (FATS), in which coronary lesions were measured quantitatively, treatment induced clear regression of coronary atherosclerosis and also markedly decreased coronary events. The beneficial effect on coronary lesions in these studies appears to be proportional to the degree of lipid lowering. In addition, new evidence suggests that aspirin and calcium antagonists might prevent the development of early coronary lesions. The identification and aggressive treatment of patients with high serum cholesterol levels can have a major impact on the development and evolution of coronary atherosclerosis.

Angiography↗
PubMed1991

Detection of early human T-cell lymphotropic virus type I antibody patterns during seroconversion among transfusion recipients.

From a cohort of human T-cell lymphotropic virus type I (HTLV-I) exposed transfusion recipients (N = 71) enrolled in the Jamaican Transfusion Study, 11 were selected for detailed laboratory evaluation. All recipients were followed at monthly intervals for 6 months and then bimonthly up to 1 year for evidence of HTLV-I seroconversion. Without regard to results on screening assays, pretransfusion and posttransfusion samples were tested with two licensed HTLV-1 whole-virus screening enzyme immunoassays (EIAs), recombinant EIAs for antibody against tax (p40x) and p21e envelope, standard whole virus Western blot (WB), WB enhanced with recombinant p21e, and radioimmunoprecipitation assay (RIPA). In the early period posttransfusion, antibody to gag core protein was predominant with anti-p24 generally appearing before anti-p19. Recombinant anti-p21e envelope protein, in EIA and WB format, was frequently the earliest envelope reactivity detected, while anti-gp46 in WB and anti-gp61/68 in RIPA system appeared later. Anti-tax antibodies appeared later in the time course of seroconversion. The whole-virus EIAs were less sensitive than the confirmatory assays. The combination of WB and RIPA or WB enhanced with recombinant p21e appeared equally effective in confirming samples as positive by the Public Health Service two gene group confirmatory algorithm. However, specificity of this assay approach could not be addressed in this study.

Adolescent↗
PubMed1991

Assessment of pancreatic function in screened infants with cystic fibrosis.

Previously we have reported that 37% of infants with cystic fibrosis diagnosed by neonatal screening with the dried blood spot immunoreactive trypsin assay have pancreatic sufficiency. However, 34 of the 78 infants had pancreatic function tests an average 2.3 years after diagnosis, thus it was possible that the percentage with neonatal pancreatic sufficiency was underestimated, due to the loss of pancreatic function with time in some infants. To assess this hypothesis we have assessed pancreatic function at the time of diagnosis in a further 20 infants since the completion of the previous study. Results of fecal fat determinations and/or pancreatic stimulation tests indicate that 10 (50%) of these infants have pancreatic sufficiency. Combining these results with those of the previous study, 31 of 64 patients (48%) have pancreatic sufficiency at this early age. We have also monitored the progression of pancreatic disease in the 39 patients with pancreatic sufficiency recognized to date. Eleven have developed pancreatic insufficiency and require enzyme replacement therapy. Five others have shown further improvement of colipase secretion with age. We conclude that the dried blood immunoreactive trypsin screening program for cystic fibrosis does recognize patients with pancreatic sufficiency, and at diagnosis nearly half the patients are in this category. To date, 28% of patients with pancreatic sufficiency have demonstrated a variable decline in pancreatic function with age.

Cystic Fibrosis↗
PubMed1991

Clinical and angiographic features and prognostic significance of early postinfarction angina with and without electrocardiographic signs of transient ischemia.

PURPOSE: The goal of the study was to characterize the clinical and angiographic characteristics and the prognostic significance of early postinfarction angina associated or unassociated with ST-T changes. PATIENTS AND METHODS: Four hundred forty-nine consecutive patients surviving an acute myocardial infarction and catheterized before hospital discharge were included. They were closely monitored in the coronary care unit and a 12-lead electrocardiogram (ECG) was promptly obtained before the administration of nitroglycerin whenever chest pain suggestive of ischemia occurred. Complete follow-up information was obtained for all patients a mean of 14 +/- 8 months after the qualifying infarction. RESULTS: Early postinfarction angina occurred in 164 patients. Transient ST-T changes were documented during pain in 79 patients and were absent in 85. Compared with patients without postinfarction angina, patients with angina without ST-T changes were older and had a more frequent past history of angina (42% versus 28%, p = 0.01). They also more often had a non-Q-wave myocardial infarction with lower peak creatine kinase blood level elevation. At angiography, patients with angina had more extensive coronary artery disease (1.9 +/- 0.8 diseased vessels per patient versus 1.6 +/- 0.8, p less than 0.05) and more left ventricular segments at jeopardy by a significant coronary artery stenosis (1.5 +/- 1.1 versus 1.2 +/- 1.1, p less than 0.05). The presence of ST-T changes during chest pain was associated with a further increase in the severity of coronary artery disease (2.1 +/- 0.8 diseased vessels per patient, p less than 0.05) and with a less well-developed collateral circulation (18% versus 34% of patients, p = 0.01) that was more often compromised by a coronary artery stenosis (22% versus 8% of patients, p = 0.008). In-hospital infarct extension occurred in 2% of patients without angina, 3.5% of patients with angina without ECG changes, and 28% of patients with angina and ST-T changes (p less than 0.01). The 2-year survival was similar in the first two groups (90% and 96%), and poorer (83%, p = 0.02) in patients with ST-T changes. Survival rates without myocardial infarction were respectively 80%, 78%, and 67% (p less than 0.004). CONCLUSION: A gradient in the severity of coronary artery disease and in the extent of myocardium at jeopardy exists from patients with no postinfarction angina to patients with angina and to patients with angina accompanied by ECG signs of ischemia. The presence of ST-T changes during pain indicates a much less favorable clinical outcome.

Angina Pectoris↗
PubMed1991

Percutaneous mitral valvuloplasty in surgical high risk patients.

Among 126 consecutive patients undergoing percutaneous mitral valvuloplasty, 34 were judged to be at high risk for surgery on the basis of age greater than 70 years (n = 13), New York Heart Association functional class IV (n = 11), ejection fraction less than or equal to 35% (n = 3), severe pulmonary hypertension (n = 7), need for associated coronary bypass (n = 4) or additional valve surgery (n = 20) or severe pulmonary disease (n = 3). Baseline features of the high risk group were substantially worse than those of the other patients: age (65 +/- 11 versus 49 +/- 12 years; p = 0.0001) and echocardiographic score (9.4 +/- 1.8 versus 8.2 +/- 1.5; p = 0.005) were higher, whereas cardiac output (2.9 +/- 0.9 versus 4.1 +/- 1.2 liters/min; p = 0.0001) and mitral valve area (0.9 +/- 0.4 versus 1.1 +/- 0.3 mm2; p = 0.002) were lower. Three high risk patients experienced technical failures and three others had major complications. Among the remaining 28 patients, 18 (65%) had a complete hemodynamic success, 4 (14%) an incomplete success and 6 (21%) hemodynamic failure. Stepwise logistic regression analysis retained echocardiographic score as the only factor independently predictive of success. The percent increase in mitral valve area also correlated with echocardiographic score (r = 0.51, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Multivariate clinical models and quantitative dipyridamole-thallium imaging to predict cardiac morbidity and death after vascular reconstruction.

Patients with peripheral vascular disease have a high prevalence of coronary artery disease and are at increased risk for cardiac morbidity and death after vascular reconstruction. The present study was undertaken to assess the value of 18 clinical parameters, of 7 clinical scoring systems, and of quantitative dipyridamole-thallium imaging for predicting the occurrence of postoperative myocardial infarction or cardiac death. Vascular surgery was performed in 125 patients. Thirteen postoperative cardiac events occurred, including 10 cardiac deaths and 3 nonfatal infarctions. Clinical parameters were not useful in predicting postoperative outcome. All 63 patients with normal scan results or fixed perfusion defects underwent surgery uneventfully, whereas 21% (13/62) of patients with reversible defects had a postoperative cardiac complication. By use of quantitative scintigraphic indexes we found that patients with reversible defects could be stratified into intermediate and high-risk subgroups with postoperative event rates of 5% (2/47) and 85% (11/13), respectively, despite intensive postoperative monitoring and antianginal medication. Thus in patients unable to complete a standard exercise stress test, postoperative outcome cannot be predicted clinically, whereas dipyridamole-thallium imaging successfully identified all patients who had a postoperative cardiac event. By use of quantification we found that patients with reversible defects can be stratified into an intermediate risk subgroup that can undergo surgery with minimal complication rate and a high-risk subgroup that requires coronary angiography.

Canada↗
PubMed1991

Diltiazem at reperfusion reduces neutrophil accumulation and infarct size in dogs with ischaemic myocardium.

STUDY OBJECTIVE: The aim was to demonstrate the ability of diltiazem to protect the ischaemic myocardium in the course of coronary reperfusion, and to establish if an interaction with neutrophils is implied. DESIGN: Ischaemia was induced by occluding the left anterior descending coronary artery for 90 min followed by 6 h of reperfusion with a residual critical stenosis left in place. Three groups were studied: group 1 (control) received a saline perfusion; group 2 was given a bolus injection of 400 micrograms.kg-1 of diltiazem 10 min before reperfusion, followed by 4 micrograms.kg-1.min-1 perfusion until termination of experiment; group 3 was made neutropenic by injecting a neutrophil antiserum produced in rabbits and was then treated with diltiazem, as in the second group. SUBJECTS: 60 mongrel dogs of either sex were allocated at random into one of the three groups the day before the experiment. MEASUREMENTS AND MAIN RESULTS: Diltiazem plasma concentrations ranged from 68.6(SEM 10.0) to 102.5(15.2) micrograms.litre-1 during the study. Transmural collateral blood flow, measured with 153Gd microspheres 15 min after occlusion, and area at risk, evaluated by Evans blue perfusion, did not differ among the three groups. Infarct size, estimated by triphenyltetrazolium staining of heart slices and expressed as a percentage of area at risk, was less (p less than 0.05) in the diltiazem [20.5(5.2)%] and diltiazem plus neutropenia [17.6(5.4)%] groups compared to controls [39.8(6.9)%] but neutropenia added no significant benefit to diltiazem alone. The animals treated with diltiazem alone had lower serum creatine kinase levels than controls, at 5719(891) v 14,333(2885) IU.litre-1, p less than 0.05. The neutrophilia seen in controls was virtually absent in diltiazem dogs. Myocardial neutrophil accumulation estimated by scintigraphy of 111In labelled autologous neutrophils was much less in diltiazem than in control dogs, at 3948(1228) v 11,021(2081) 111In-neutrophil.g-1 of infarct, p less than 0.02. CONCLUSIONS: Diltiazem given during reperfusion reduces infarct size by a mechanism that includes an inhibition of neutrophil accumulation in the post-ischaemic myocardium.

Animals↗
PubMed1991

Role of diltiazem in the treatment of silent myocardial ischemia.

Silent myocardial ischemia is a frequent finding when Holter monitoring is done in patients with advanced coronary disease. Silent ischemia is associated with a worse prognosis in patients with stable or unstable angina, survivors of myocardial infarction, and populations at risk for coronary disease. Whether medical therapy for silent ischemia improves prognosis is not known. In a randomized, placebo-controlled, multicenter trial of 60 patients with documented coronary disease, positive exercise tests, and ischemic episodes on Holter monitoring, long-acting diltiazem reduced ischemic episodes by 50% compared to placebo, from a mean of 5.6 to 2.8 (p less than 0.0001). Efficacy was maintained over 24 h and diltiazem also significantly improved exercise test parameters. Three smaller studies also demonstrated that diltiazem effectively reduces ambulatory ischemia; however, results with nifedipine are conflicting, with several studies showing no benefit. In contrast, beta-blockers reliably reduce ischemic episodes. The role of medical therapy for silent ischemia will be clarified only when its effect upon morbidity and mortality are determined.

Adult↗
PubMed1991

Pericardial patch angioplasty.

The authors describe the case of a man with severe left coronary ostial stenosis who was treated with direct left main angioplasty with a pericardial patch. This approach may be superior to artery bypass grafting in certain patients.

Coronary Angiography↗