PubMed Health⌕ Search

Biomedical subjects

K L Baughman

Publications and source records attributed to K L Baughman.

107 records · Page 6Linked to original sources
PubMed1982

Nifedipine in unstable angina: a double-blind, randomized trial.

We assessed the efficacy of adding nifedipine to the conventional treatment of unstable angina in 138 patients in a prospective, double-blind, randomized, placebo-controlled trial. There was no difference between the two groups in the dose of conventional antianginal medication or in age, prior myocardial infarction, ejection fraction, or other risk factors. Failure of medical treatment (defined as sudden death, myocardial infarction, or bypass surgery within four months) occurred in 43 of 70 patients given placebo and in 30 of 68 given nifedipine. Kaplan-Meier survival-curve analysis of the number and time dependence of treatment failures demonstrated a benefit of nifedipine over placebo (P = 0.03). The benefit was particularly marked in patients with ST-segment elevation during angina (P = 0.02). Side effects (transient hypotension or diarrhea) required withdrawal of the drug from four patients given nifedipine and from one given placebo. We conclude that the addition of nifedipine to conventional therapy is safe and effective in unstable angina.

Adult↗
PubMed1982

Constrictive epicarditis as a cause of delayed or absent response to pericardiectomy: a clinicopathological study.

It is widely held that constrictive pericarditis is curable by pericardiectomy, and failure to respond reflects an underlying myocardial disease. Fibrous epicarditis could account for residual cardiac constriction, and delayed hemodynamic response in some patients is an alternative explanation. To examine this, we studied the 12 consecutive patients with otherwise normal hearts treated with extensive pericardiectomy for constrictive pericarditis over the past 7 years. Three hemodynamic responses to pericardiectomy were observed: (1) rapid response, where central venous pressure (CVP) fell below 10 cm H2O by 24 hours in two patients; (2) delayed response, where CVP fell below 10 cm H2O by 48 hours in six patients; and (3) no response of CVP in four patients. The CVPs remained critically elevated (greater than 25 cm H2O) in three patients with delayed response until a sclerotic epicardial peel was resected. Another patient whose CVP of 30 cm H2O showed no change after parietal pericardiectomy was thought to have amyloid cardiomyopathy but instead at autopsy had constrictive epicardial sclerosis not recognized at parietal pericardiectomy. Histologic features of parietal pericardium had no correlation with hemodynamic response, whereas epicardial histology did correlate with hemodynamic response in four patients. The data showed a spectrum of postpericardiectomy delayed hemodynamic responses, which in some patients may be due to a slowly resolving or fixed component of fibrous epicarditis that may be clinically misconstrued as a cardiomyopathy. Interruption of visceral pericardial tissue may be as important as resection of the parietal pericardium in patients with epicardial sclerosis.

Adolescent↗
PubMed1982

Early discharge following acute myocardial infarction. Long-term follow-up of randomized patients.

Long-term follow-up was obtained on 138 patients who participated in a prospective, randomized study comparing two weeks with three weeks of hospitalization following uncomplicated acute myocardial infarction. Follow-up information was available on 123 (89%) of all randomized patients. The mean follow-up period was 35 months for those patients who died and 99 months for those who survived. No differences were found between the two groups with respect to survival, cardiac-related deaths, frequency or severity of angina pectoris, subsequent myocardial infarction, incidence of congestive heart failure, number of ventricular aneurysms, or subsequent medical therapy. A significantly greater number of survivors in both groups stopped smoking and had a normal initial heart size than those who died. This long-term follow-up study further supports the conclusions of earlier short-term studies that two weeks of hospitalization is safe in patients with uncomplicated acute myocardial infarction.

Adult↗
PubMed1981

Transluminal coronary angioplasty of postmortem human hearts.

Twelve autopsy human hearts were submitted to coronary angiography and coronary arterial balloon angioplasty. The effect of angioplasty was determined by follow-up coronary angiography as well as gross and microscopy inspection of the coronary arteries dilated. Fifty-four dilations were performed in 24 coronary arteries. Angiographically 50 of the 54 dilations resulted in a mean (+/- standard deviation) increase in luminal diameter ranging from 1.9 +/- 0.9 to 2.7 +/- 0.8 mm. Failure to increase luminal size was usually related to a predilation coronary diameter greater than that of the inflated angioplasty balloon. Dilation resulted in mural disruption with intimal or medial tears, or both, in 65 percent of arteries dilated. Disruption was more frequent in arteries with atherosclerosis and calcification. The mechanism of luminal enlargement in coronary angioplasty may be focal damage to the arterial wall with intimal or medial splitting as opposed to plaque compression as initially suggested.

Adolescent↗
PubMed1981

Effects of coronary artery reperfusion on myocardial infarct size and survival in conscious dogs.

The effects of coronary artery reperfusion at 1 and 3 hours after coronary artery occlusion were examined on myocardial infarct size and survival in conscious dogs. Left circumflex coronary artery occlusion was induced by inflating an hydraulic occluder and confirmed thereafter by measuring the absence of coronary blood flow. Of the 77 dogs that underwent coronary artery occlusion, 18 died within 1 hour. Of the 59 remaining dogs, permanent coronary artery occlusion was carried out in 31 dogs, 12 underwent reperfusion after 1 hour and 16 underwent reperfusion after 3 hours. Survival at 1 week was enhanced significantly (p < 0.01) by reperfusion carried out at either 1 or 3 hours; only 29% of dogs with permanent coronary artery occlusion survived, whereas 83% and 75% of dogs survived 1 week with reperfusion at 1 hour and 3 hours, respectively. Average infarct size at 1 week was smaller in dogs with reperfusion (NS). The inability to reach statistical significance was most likely the result of two factors: (1) There was a marked variation in infarct size in dogs with permanent coronary artery occlusion--infarcts averaged 21.3 +/- 7.5% and ranged from 0.7-72.6% of the left ventricle. (2) Dogs that died 1-7 days after coronary artery occlusion had significantly (p < 0.05) larger infarcts (40 +/- 4% of left ventricle) than those that survived 1 week in any of the three groups. Thus, if all dogs had survived 1 week, a beneficial effect on infarct size could have been demonstrated. Nevertheless, coronary artery reperfusion at either 1 or 3 hours after coronary artery occlusion induces a striking beneficial effect on survival, which is of the utmost clinical significance.

Animals↗
PubMed1980

Scanning electron microscopy after coronary transluminal angioplasty of normal canine coronary arteries.

Percutaneous coronary transluminal angioplasty is currently being proposed as a possible treatment for some patients with significant coronary arterial lesions. In this study scanning electron microscopy was used to assess the morphologic changes caused by the angioplasty balloon catheter in normal canine coronary arteries. Balloon inflation uniformly caused endothelial denudation with virtually immediate dense platelet adhesion to the subendothelial matrix. This platelet adhesion was unaffected by pretreatment with aspirin (35 mg/kg body weight) or heparin (2,000 units). However, intravenous administration of low molecular weight dextran almost completely prevented platelet adhesion to the exposed subendothelial connective tissues. It is concluded that even in normal canine coronary arteries (1) loss of endothelium is seen after transluminal angioplasty; (2) this endothelial damage stimulates platelet adhesion and thrombus formation; and (3) the immediate layering of platelets can be prevented by administration of low molecular weight dextran.

Animals↗
PubMed1980

Transluminal angioplasty: correlation of morphologic and angiographic findings in an experimental model.

The morphologic consequences of transluminal angioplasty of stenotic atherosclerotic coronary arteries are unknown. This study describes the production of aortoiliac atherosclerosis in rabbits and reports the morphologic changes after transluminal angioplasty of stenotic arterial lesions. Atherosclerotic lesions were evaluated angiographically before and after transluminal angioplasty and were studied histologically and by electron microscopy after angioplasty. Moderatley stenotic aortic segments showed denudation of endothelial cells and deposition of a carpet of platelets enmeshed in fibrin. Medial and intimal compression were not seen. Intimal plaque disruption and splitting of atheromatous plaques were observed in more stenotic vessels where dilatation during angioplasty is relatively greater. Transluminal angioplasty, therefore, acutely causes desquamation of endothelial cells and superficial plaque elements, splitting of atheroma and subsequent deposition of platelets and fibrin in the area of angioplasty. This experimental model may be useful to evaluate the morphologic changes after angioplasty and might be used in further studies to determine the long-term pathophysiologic changes after transluminal angioplasty.

Animals↗
PubMed1977

Controlled comparison of amikacin and gentamicin.

Amikacin or gentamicin was used to treat 174 patients with suspected severe gram-negative infections in a prospective, randomized, double-blind trial. Enteric gram-negative bacilli were pathogenic in 71 cases (39 treated with amikacin, and 32 with gentamicin). Amikacin was effective in 10 to 12 bacteremias, 21 of 24 urinary-tract infections, two of five pneumonias and four of six other serious tissue infections. The toal favorable response rate was 77 per cent for amikacin and 78 per cent for gentamicin. Nephrotoxicity and auditory toxicity could be evaluated in 124 and 67 cases respectively. Definite nephrotoxicity developed in five of 62 (8 per cent) receiving amikacin and seven of 62 (11 per cent) given gentamicin, and possible nephrotoxicity developed in four patients in both groups. Definite ototoxicity developed in four patients in both groups. Definite otoxicity developed in two of 34 (6 per cent) and three of 30 (10 per cent) respectively. These differences were not statistically significant (by chisquare analysis, P greater than 0.05). The results indicate that amikacin is effective against severe gram-negative infections and is not more and not less ototoxic or nephrotoxic than gentamicin.

Adult↗
PubMed1977

Systemic mastocytosis in a patient with polycythemia vera treated with radioactive phosphorus.

Systemic mastocytosis occurred as a fatal event in a patient with long-standing polycythemia vera. The patient had been treated over the course of 21 yr with radioactive phosphorus. Possible relationships between mastocytosis and polycythemia vera, and also between mastocytosis and treatment with ionizing radiation, are discussed. Histopathologic and electron microscopic findings are illustrated. Difficulties in establishing the diagnosis of mast cell disease in this setting are also described.

Biopsy↗
PubMed1976

Concentrations of gentamicin and amikacin in human kidneys.

High kidney concentrations of gentamicin or amikacin, measured by an enzymological assay, were found in 9 of 10 patients who died during therapy with these aminoglycosides. Renal cortical concentrations of gentamicin ranged from 140 to 540 mug/g of tissue, with medullary levels of 128 to 230 mug/g. Concentrations of amikacin ranged from 365 to 1,030 mug/g in the cortex and from 270 to 718 mug/g in the medulla. The only patient with low kidney concentrations was an infant who received a single dose of gentamicin. Tissue levels were high in patients with both normal and abnormal renal function. Our results indicate that gentamicin and amikacin are concentrated in renal cortical and medullary tissue.

Aged↗
PubMedDate not supplied

Severe lymphocytic endothelialitis associated with coronary artery spasm in a heart transplant recipient.

Coronary artery spasm plays an important role in ischemic heart disease, particularly variant angina. We report the case of a 59-year-old man who developed severe diffuse coronary artery spasm 11 months after he received a heart transplant. The spasm was reversed by a single dose of sublingual nitroglycerin; however, the patient died 9 days later of Pneumocystis carinii pneumonia. Postmortem examination of this patient's heart revealed accelerated arteriosclerosis, with a prominent diffuse lymphocytic endothelialitis in the coronary arteries. The lymphocytic endothelialitis was characterized by the presence of numerous T lymphocytes and macrophages in the subendothelial space and by histologic changes suggesting injury to the endothelial cells. Although an association does not prove a causal relationship, the findings of accelerated arteriosclerosis and lymphocytic endothelialitis in a patient with coronary artery spasm suggests that these processes may be etiologically linked.

Coronary Artery Disease↗
PubMedDate not supplied

Comparison of rejection in the atrioventricular node and bundles with the working myocardium in transplanted hearts.

At present the monitoring of heart transplant patients for rejection is done by endomyocardial biopsy. It has been proposed that ECG assessments of conduction delay may provide a noninvasive means of detecting rejection. To determine whether rejection in the atrioventricular node and conduction bundles reflects rejection in the working myocardium, we studied 21 transplanted hearts from 21 cardiac allograft recipients. Twenty of the hearts were obtained at autopsy, and one was obtained from a patient who underwent a second transplant procedure. The atrioventricular conduction tissues, the ventricular and atrial free walls, and the interventricular and interatrial septa from these hearts were examined for histologic evidence of rejection. Of the 21 hearts, 17 showed histologic changes of acute allograft rejection. Of the 17, rejection involved the conducting system and the myocardium equally in 11. In 6 of the 17 hearts, rejection involved the working myocardium more severely than it did the conducting system. Of interest, nonrejection pathologic changes were also noted in the conducting systems of several hearts. Severe accelerated arteriosclerosis was found in the artery to the atrioventricular node in one case, and lesser degrees of accelerated arteriosclerosis in this artery were found in two additional cases. In one case, lymphoid infiltrates, consistent with posttransplant lymphoproliferative disorder, were noted in the vicinity of the atrioventricular node, and several hearts demonstrated operative trauma or ischemic changes that appeared to involve the conducting system. These results suggest that although there may be a morphologic basis for using electrophysiologic changes in the conducting system to monitor heart allograft recipients for rejection, caution should be exercised in interpreting these changes.

Adult↗
PubMedDate not supplied

Persistent pulmonary hypertension after heterotopic heart transplantation: a case report.

Right-sided failure occurring in the donor heart immediately after transplantation is primarily caused by increased recipient pulmonary artery pressure and resistance and represents one of the leading causes of perioperative mortality associated with orthotopic heart transplantation. After transplantation pulmonary hypertension gradually declines, returning to near normal levels within 30 days of transplantation. This article describes a case report of the persistence of pulmonary hypertension after heterotopic heart transplantation. The heterotopic position was utilized because of marked elevation of the pulmonary artery resistance (18 Wood units) calculated at the time of operation. Cardiac catheterization data-obtained during the subsequent 6 months of follow-up showed persistent elevation of pulmonary artery pressure and pulmonary vascular resistance. The patient, however, clinically continues to feel well and remains asymptomatic without signs of right-sided heart failure. Indications, suggested advantages, and demonstrated disadvantages of heterotopic heart transplantation are discussed.

Adult↗
PubMedDate not supplied

Arteriolar vasculitis on endomyocardial biopsy: a histologic predictor of poor outcome in cyclosporine-treated heart transplant recipients.

The histologic pattern of severe, potentially lethal cardiac rejection in transplant recipients who are treated with cyclosporine may be difficult to distinguish from mild or moderate rejection. The purpose of this study was to determine whether specific histologic abnormalities seen on endomyocardial biopsy could identify which histologic patterns of rejection are associated with progression to graft dysfunction or graft failure. We performed a blinded, retrospective analysis of endomyocardial biopsies from our initial 19 transplant recipients. Group 1 was composed of five patients who developed graft failure or dysfunction after transplantation. Group 2 was composed of the remaining 14 patients with normal hemodynamics and function at heart catheterization 1 year after transplantation. Seventeen histologic parameters were semiquantitatively graded, and comparisons between the two groups were made with the Student's t test. Of the 17 parameters, only arteriolar vasculitis was significantly increased in group 1 versus group 2 biopsies (p = 0.002). Arteriolar vasculitis was identified in four of five patients in group 1 and was unique to group 1. Of 53 group 1 biopsies, eight patients had foci of arteriolar vasculitis and were seen up to 88 days before graft failure. Therefore the finding of arteriolar vasculitis on endomyocardial biopsy may identify high risk rejection episodes in transplant recipients who are treated with cyclosporine.

Adult↗
PubMedDate not supplied

Use of theophylline for treatment of prolonged sinus node dysfunction in human orthotopic heart transplantation.

Sinus node dysfunction may complicate heart transplantation in over 50% of cases, leading to prolonged bradyarrhythmias in 20% of recipients. Permanent pacemaker implantation, the standard treatment for such persistent rhythm disturbances, can result in significant complications in this setting. A protocol with theophylline, a methylxanthine known to reverse the sinus node electrophysiologic abnormalities observed in transplant patients, was initiated at our institution in October 1989 to treat posttransplantation bradyarrhythmias and to reduce the need for pacemaker implantation. Patients with sinus or nodal bradycardia or sinus arrest were given theophylline orally; the drug was initiated in 15 of 38 patients (39.5%), 3 to 24 days after transplantation. Mean duration of treatment was 57.4 days (range, 20 to 105 days). Normal sinus rhythm with a rate of more than 90 beats/min was restored in 14 of 15 patients (93.3%). Permanent pacing was required in one patient. Transplant recipients before October 1989 (group 1, n = 112) were compared with subsequent transplant recipients (group 2, n = 38). These groups did not differ significantly in incidence of bradyarrhythmias or potential risk factors for posttransplantation sinus node dysfunction, though a greater preoperative use of amiodarone occurred in group 2. Permanent pacemaker requirement was significantly reduced from 16.1% in group 1 to 2.6% in group 2 (p < 0.05) with the introduction of theophylline. Theophylline is effective treatment for posttransplantation bradyarrhythmias, thereby resulting in a reduced need for pacemaker implantation.

Adult↗
PubMedDate not supplied

Complications of endomyocardial biopsy in heart transplant patients.

Despite the increasing use of alternative techniques, endomyocardial biopsy remains the primary method for diagnosing cardiac allograft rejection. Improved patient longevity and an increasing number of transplantation centers are resulting in an increase in the number of biopsies performed. Although endomyocardial biopsy is usually considered a safe procedure, no large studies of the risks of endomyocardial biopsy specifically in the transplant population have been undertaken. To determine the risk of endomyocardial biopsy in these patients, we reviewed 2454 endomyocardial biopsies performed from January 1983 to December 1990 in 133 cardiac allograft patients at our institution. At the time of each endomyocardial biopsy, a worksheet was completed detailing the patient's interval history, the site of vascular introduction, the number of attempts, the number of specimens, and any complications encountered. A total of 74 (3.0%) complications occurred. Fifty-six (2.3%) complications were associated with catheter insertion, including carotid puncture (1.8%), vasovagal reaction (0.1%), and prolonged bleeding (0.4%). Complications during biopsy included arrhythmias (0.25%) and conduction abnormalities (0.2%). In addition, we observed five episodes (three patients) of allergic reaction to a reusable bioptome and one case of pacemaker dislodgement. All complications were without significant long-term sequelae. In contrast to the cardiomyopathy population, no ventricular perforations or deaths occurred. Thus although endomyocardial biopsy has some risk, it continues to be a safe and effective way of monitoring rejection.

Adult↗