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Biomedical subjects

J F King

Publications and source records attributed to J F King.

At least 37 records · Page 2Linked to original sources
PubMed1991

Catheter balloon valvuloplasty of stenotic aortic valves--Part II: Balloon valvuloplasty during life subsequent tissue examination.

This review describes 23 patients with aortic valve stenosis who underwent balloon valvuloplasty during life and had subsequent valve tissue examined at the time of aortic valve replacement or at necropsy. Of 23 stenotic aortic valves, 17 were examined within 30 days (early) after balloon dilation. Of these 94% had nonrheumatic (nonfused commissures) etiologies for the aortic stenosis. Of the 6 valves examined after 30 days (late) (restenosis), mechanisms of restenosis involve refusion of split commissures and probable elastic recoil. Clinical prediction of the aortic stenosis etiology prior to balloon valvuloplasty may help predict short- and long-term success of the dilation procedure.

Adult↗
PubMed1990

Percutaneous transluminal aortic valvuloplasty--the acute outcome and follow-up of 149 patients who underwent the double balloon technique.

Double balloon percutaneous transluminal aortic valvuloplasty (PTAV) was performed on 149 patients (76 male (51%), mean age 76 +/- 11 years) whose symptoms included severe congestive heart failure in 127 cases (82%), syncope in 21 (14%) and angina in six (4%). Significant changes (P less than 0.05) in peak systolic (83 +/- 36 to 38 +/- 30 mmHg) and mean gradient (68 +/- 25 to 36 +/- 21 mmHg), and aortic valve area (0.6 +/- 0.2 to 1.0 +/- 0.4 cm2) were achieved in 130/149 patients (87%). Complications included an overall in-hospital mortality of 13%, (10.0% excluding the six deaths occurring in 18 moribund patients), a neurologic deficit incidence of 3%, and surgical arterial entry site repair 3.0% (14/47) of patients. Multivariate analysis identified congestive heart failure (NYHA Class IV), left ventricular ejection fraction, cardiac output and coronary artery disease as independent variables significantly affecting in-hospital mortality. Predictors of poor long-term survival were degree of heart failure, and coronary artery disease. The cumulative probability of survival at 24 months was 52 +/- 5% (excluding non-cardiac deaths, was 66 +/- 3%). Follow-up (mean time: 16 +/- 7 months) of 130 patients discharged alive revealed 41 late deaths (26 cardiac related). Sixty-two patients (70%) were symptomatically improved; 17 patients had symptom recurrence and underwent repeat valvuloplasty, and 10 patients valve replacement. Follow-up catheterization of 18 asymptomatic patients revealed that 11 patients had silently restenosed. These data indicate that aortic valvuloplasty is a palliative therapy for elderly patients, who are poor surgical candidates, with symptomatic calcific aortic stenosis with reasonable clinical success and long-term survival when considering their clinical status, but with a significant restenosis rate.

Aged↗
PubMed1990

An investigation of the maternal antecedents of perinatal mortality in 2 large teaching hospitals.

Perinatal mortality reviews are a form of quality assurance, and the classification of perinatal mortality would be most useful if it assisted in strategies for prevention. Whilst the value of clinicopathological (autopsy) and separate neonatal classifications is recognized, the Whitfield classification, modified for Australian conditions and applied to 393 cases, clearly identified the major obstetric problems leading to perinatal death, and may therefore contribute to continuing improvement in prenatal care.

Birth Weight↗
PubMed1989

Percutaneous transluminal aortic valvuloplasty: acute outcome and follow-up of 125 patients.

Percutaneous transluminal aortic valvuloplasty was performed on 125 patients (59 men [47%], mean age 76 +/- 13 years) between July 1986 and May 1988, with presenting symptoms of severe congestive heart failure in 88 (70%), moribund state in 15 (12%) and syncope in 17 (14%). Surgical valve replacement was considered unsuitable in 79% of cases. A multiple balloon technique was utilized in 119 patients (95%). Valvuloplasty produced significant changes in peak pressure gradient (87 +/- 38 to 32 +/- 17 mm Hg), mean pressure gradient (70 +/- 26 to 30 +/- 13 mm Hg) and valve area (0.6 +/- 0.2 to 1.0 +/- 0.3 cm2). Complications included: in-hospital mortality in 10% (6 of 13 deaths in moribund patients), neurologic deficit in 3% and myocardial infarction in 2%. Arterial repair was required at 12 (4%) of 325 entry sites. Multivariate analysis identified severe congestive heart failure, preprocedure left ventricular ejection fraction and cardiac output as the only independent variables significantly affecting mortality. The cumulative probability of survival at 12 months was 62 +/- 6% and, excluding non-cardiac deaths, was 77 +/- 5%. At a mean of 12 +/- 4 months' follow-up, 55 of 72 patients were symptomatically improved; 10 patients with symptom recurrence underwent repeat valvuloplasty and 5 had valve replacement. Cardiac catheterization was repeated in 12 symptomatically improved patients, 9 of whom had valve restenosis. These data indicate that aortic valvuloplasty should be considered a palliative therapy for elderly patients with symptomatic calcific aortic stenosis who are poor surgical candidates.

Aged↗
PubMed1989

Aortic annular tear after valvuloplasty: the role of aortic annulus echocardiographic measurement.

Following percutaneous transluminal aortic valvuloplasty, 2/100 patients (2%) developed significant aortic insufficiency as a result of an aortic annular tear. Both patients underwent emergency aortic valve replacement and survived the operation. One patient died 4 weeks postoperatively from sepsis and multiorgan failure, and the other patient had a benign postoperative course. In both cases, the balloon area significantly exceeded the aortic annular area and caused the complication. Review of the balloon area-aortic annular area ratio in our series showed that a value of less than 1.2 was not associated with this complication.

Aged↗
PubMed1989

Stimulation of atrial natriuretic peptide and vasopressin during percutaneous transluminal aortic valvuloplasty.

The objective of this study was to determine the effects of transient aortic valve occlusion (balloon valvuloplasty) on vasoactive hormones in patients with heart failure. Plasma atrial natriuretic peptide, vasopressin, aldosterone, adrenocorticotropic hormone (ACTH), and plasma renin activity were measured before, immediately after, and 30 minutes and 18 to 24 hours following balloon inflation in 18 patients. Mean right atrial and pulmonary wedge pressures were 6 and 18 mm Hg before inflations, respectively, and were unchanged after balloon inflations (5 and 13 mm Hg, respectively). Systemic systolic/diastolic pressures were 139 +/- 8/65 +/- 4 mm Hg before occlusion, decreased to 47 +/- 5/34 +/- 3 mm Hg during occlusion, and returned to baseline after occlusions. Baseline atrial natriuretic peptide levels were 267 +/- 43 pg/ml and increased to 513 +/- 71 pg/ml after balloon inflations. Vasopressin levels before occlusion were 9.1 +/- 2.2 pg/ml and increased to 21.4 +/- 4.8 pg/ml after balloon inflations. Plasma renin activity was 5.4 +/- 1.4 ng/ml/hr before inflations and was not significantly changed after balloon inflations. No clinically significant changes in plasma sodium, potassium, creatinine, and osmolality were observed after the procedure. Aldosterone increased from 23 +/- 4 to 40 +/- 7 ng/dl 10 minutes after the last inflation. Plasma ACTH measured in seven patients with increased aldosterone was 28 +/- 8 pg/ml before and increased to 295 +/- 157 pg/ml 10 minutes after balloon inflations. The increases in natriuretic peptide and vasopressin were likely due to elevated intracardiac and decreased arterial pressures, respectively; they persisted in spite of no clinically significant changes in filling pressures 12 to 24 hours after the procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗
PubMed1989

Risk factors and the anatomic distribution of coronary artery disease.

Differences in the importance of risk factors according to the anatomic location of coronary artery disease (CAD) were assessed in 4722 men and 1069 women who underwent arteriography. Examined characteristics included total and high-density lipoprotein (HDL)-cholesterol, triglycerides, obesity, smoking, alcohol consumption, diabetes, and hypertension. Of these risk factors, the ratio of total to HDL-cholesterol showed the highest correlation with the overall severity of CAD (r = 0.24, men; r = 0.38, women); in contrast, its relation to left main (LM) disease was much lower (r = 0.10, men; r = 0.08 women) than were correlations with stenotic disease in the left anterior descending, circumflex, and right coronary arteries. Other risk factors also showed weaker associations with LM disease than with stenoses in other vessels, and none was related to increased LM disease after controlling for disease in other vessels. For example, as compared with men who had no significant CAD, those with 1-, 2-, and 3-vessel disease had mean increases in total cholesterol of 12, 18, and 19 mg/dl, respectively. In contrast, after adjusting for disease in other vessels, LM disease (present in 293 men) was associated with only a 4 mg/dl increase in mean cholesterol levels (P = 0.20). These results indicate that the relation of risk factors to CAD differs according to the location of the stenotic disease, and that LM disease is poorly predicted by the standard risk factors.

Adult↗
PubMed1989

Biologic variation of common hematologic laboratory quantities in the elderly.

Analytic, within-subject, and between-subject biologic variations were estimated for leukocytes, erythrocytes, hemoglobin, hematocrit, mean cell volume (MCV), mean cell hemoglobin (MCH), mean cell hemoglobin content (MCHC), platelets, and a three-component differential count (lymphocytes, monocytes, and granulocytes in terms of both concentration and percentage of leukocytes) in cohorts of 12 male and 12 female healthy elderly subjects. The assays were performed with an Ortho ELT-800 automated analyzer. The estimates of within-subject biologic variation were similar to published data on young subjects, indicating that this aspect of homeostasis is not compromised in the elderly. The data were used to derive objective analytic goals; goals were surpassed except for assays of erythrocytes, hematocrit, and the derived MCV, MCH, and MCHC. The changes required for serial results to be significantly different were determined and found to be generally valid because most quantities have no heterogeneity of within-subject variation. All quantities had significant individuality; in consequence, conventional population-based reference values are of limited utility, and screening using reference limits will not detect latent or early disease in many subjects.

Aged↗
PubMed1989

Restenosis after angioplasty: mechanisms and clinical experience.

The conundrum of restenosis remains the most significant challenge in revascularization techniques. This article reviews the current understanding of restenosis based upon laboratory investigations, clinical experience, and the efficacy of mechanical and pharmacologic interventions that have been attempted to prevent and/or reduce its occurrence. However, terminology really comes into play because restenosis is really the mechanism by which the body heals and is not a rapid deposition of atherosclerotic plaque.

Angioplasty, Balloon, Coronary↗
PubMed1988

Maternal mortality in British Columbia in 1971-86.

We reviewed the 56 maternal deaths in British Columbia in 1971-78 and 1979-86 identified through the provincial Ministry of Health and compared the findings with data for the two preceding 8-year periods. The maternal death rate, defined as the number of deaths directly or indirectly related to pregnancy or delivery per 100,000 live births, decreased from 42 in 1955-62 to 5 in 1979-86. In the same interval the number of direct obstetric deaths decreased from 100 to 10 and the number of indirect deaths from 29 to 8. The number of deaths due to abortion decreased from 32 to 1. There was no change in the number of deaths among North American Indians. There was also no change in the number of deaths due to hypertension, most of which were avoidable; these findings have stimulated intensive teaching efforts to increase recognition and improve management of the problem. Review of maternal deaths can help identify deficiencies in the quality of care and can direct measures aimed at further reducing the maternal death rate.

British Columbia↗
PubMed1988

Beta-mimetics in preterm labour: an overview of the randomized controlled trials.

Controversy continues about the use of beta-mimetic drugs in preterm labour. One reason for this is that the adequately controlled trials of these drugs have all been small and have thus provided very imprecise estimates of their effects. We have therefore conducted a 'meta-analysis' using data relating to 890 women who participated in the 16 methodologically acceptable controlled trials of these agents in the treatment of preterm labour. This analysis demonstrates an unequivocal effect of beta-mimetic tocolytic administration in delaying delivery, and this is reflected in a reduction in the frequency of preterm birth and low birthweight. However, no beneficial effect of this treatment on perinatal mortality or severe neonatal respiratory disorders could be detected.

Adrenergic beta-Agonists↗
PubMed1987

Risk factors among patients undergoing repeat aorta-coronary bypass procedures.

It is estimated that as many as 7% of patients who have an aorta-coronary bypass operation will require a second bypass procedure within 10 to 12 years. Using information from the Milwaukee Cardiovascular Data Registry, we matched 166 men who underwent two coronary bypass operations at least 6 months apart, between 1968 and 1981, with 428 patients who had a single procedure. Patients were matched according to date of operation and left ventricular wall motility function for analysis of risk factors for repeat operation. Elevated triglyceride levels were found to be the strongest risk factors associated with reoperation. In addition, both younger age and less complete revascularization during the first operation were significant predictive factors of repeat operation. The results suggest that efforts to reduce plasma triglyceride levels and ensure adequate revascularization may significantly reduce the need for repeat coronary bypass.

Age Factors↗
PubMed1987

A randomized trial of electronic fetal monitoring in preterm labor.

Intrapartum electronic fetal heart rate (FHR) monitoring and fetal blood gas sampling were compared with periodic auscultation of FHR in a multicentered randomized trial of preterm singleton pregnancies with fetal weights of 700-1750 g. Two hundred forty-six pregnancies were studied (electronic FHR monitoring N = 122, auscultation N = 124). Perinatal or infant death was associated with 14% of pregnancies with electronic FHR monitoring and 15% with auscultation. No significant differences were noted in the prevalence of low five-minute Apgar scores, intrapartum acidosis, intracranial hemorrhage, or frequency of cesarean section (P greater than .10). Compared with electronic FHR monitoring, intrapartum auscultation as done in this study is unlikely to be associated with detectable differences in perinatal outcomes within the high-risk setting of preterm labor.

Apgar Score↗
PubMed1984

Perinatal changes in a digoxin-like immunoreactive substance.

An endogenous digoxin-like immunoreactive substance(s) (DLIS) exists in the serum of premature and full term infants not receiving digoxin. We followed serum changes in DLIS concentration sequentially over the first 14 postnatal days in 24 premature neonates who did not receive digoxin in the intensive care nursery. All infants had measurable levels (greater than 0.6 ng/ml) of DLIS in their serum. There was a distinct peak in DLIS concentration in 19 of 24 infants occurring at 4 +/- 1.6 (SD) days after birth (range, 1-8 days). No peak was found in five infants. The peak serum level of DLIS obtained in the first 8 days of life was negatively correlated with gestational age and birth weight. DLIS levels in amniotic fluid remained constant from 16 to 33 weeks of gestation but rose from 33 wk to term. DLIS concentrations in umbilical artery, umbilical vein, and maternal serum at normal full term delivery suggested that DLIS was of fetal origin. DLIS and digoxin concentrations are additive when present in the same serum sample if measured by standard radioimmunoassay methods.

Aging↗
PubMed1981

Two-dimensional echocardiography in the diagnosis of left atrial myxoma.

We performed M-mode echocardiograms on 11 patients who later had left atrial myxomas removed at operations. Seven of these 11 patients were also examined with two-dimensional echocardiography. M-mode echocardiography showed the characteristic pattern of a left atrial mass entering the mitral orifice during diastole in nine of the 11 patients. M-mode echocardiographic findings were equivocal in two patients because a short tumour stalk prevented significant motion of the tumour. Cross-sectional echocardiography clearly showed a left atrial mass attached by a stalk to the interatrial septum in all seven patients examined, including one patient in whom the tumour was immobile. Three-dimensional measurements of tumour size made from orthogonal cross-sectional echocardiographic planes were within 6 mm of similar measurements made on the excised tumours.

Adolescent↗