Biomedical subjects

K M Fox

Publications and source records attributed to K M Fox.

At least 55 records · Page 3Linked to original sources

PubMed1998

Comparison of 201Tl, 99mTc-tetrofosmin, and dobutamine magnetic resonance imaging for identifying hibernating myocardium.

BACKGROUND: Both radionuclide perfusion tracers and contractile response to dobutamine have been used to identify hibernating myocardium. The aim was to compare 201Tl (thallium) single photon emission CT (SPECT), 99mTc-tetrofosmin (tetrofosmin) SPECT, and dobutamine cine MRI for identifying regions of reversible myocardial dysfunction. METHODS AND RESULTS: Thirty patients with 3-vessel coronary artery disease and impaired left ventricular function (mean LVEF, 24.0%; SD, 8.3%) scheduled for coronary bypass grafting were recruited. All underwent rest/dobutamine stress (5 to 10 microg . kg-1 . min-1) cine MRI, stress/rest tetrofosmin SPECT, and stress/redistribution and separate-day rest/redistribution thallium SPECT before surgery. Stress/redistribution thallium SPECT and resting MRI were repeated after surgery. In a 9-segment model, SPECT images were scored visually for tracer uptake, which was also measured from a polar plot of myocardial counts. MRI was scored visually for endocardial motion, myocardial thickening, and thickness. Five patients died before follow-up, and 2 declined postoperative investigation. In the remaining 23 patients, mean LVEF increased from 24.0% (SD, 8.3%) to 29.7% (SD, 11.1%) (P<0.05). Of 207 segments analyzed, 145 had significantly abnormal wall motion before surgery, and 82 of these improved function after revascularization. The criteria for predicting recovery of severely hypokinetic segments on preoperative imaging were tracer uptake graded "moderately reduced" or better, or positive inotropic response on dobutamine MRI. Late-rest thallium images showed the highest sensitivity (76%), compared with stress-redistribution thallium (68%) and rest tetrofosmin (66%) (P<0.05). All 3 tracer techniques were nonspecific (44%, 51%, and 49%, respectively). Redistribution of thallium after the resting injection was insensitive (18%) but highly specific (83%). Inotropic response to dobutamine was also insensitive (50%) but specific (81%). CONCLUSIONS: Radionuclide uptake is a sensitive but nonspecific predictor of myocardial functional recovery, whereas dobutamine MRI is specific but insensitive.

Adult↗

PubMed1998

The use of an implantable left ventricular assist device in a patient with cardiogenic shock following acute myocardial infarction.

We report the successful long-term use of an implantable left ventricular assist device in a 42-year old patient who suffered cardiogenic shock after an acute anterior myocardial infarction unresponsive to recanalisation of the infarct-related artery and intra-aortic balloon counterpulsation. Attempts to wean our patient from the assist device were not successful and the patient underwent cardiac transplantation after 35 weeks on device assistance. The intermediate and long-term use of an implantable left ventricular assist device may be lifesaving in post-myocardial infarction cardiogenic shock and may allow sufficient time for any stunned myocardium to recover. Should there be no recovery, the device acts as a bridge to cardiac transplantation.

Adult↗

PubMed1998

Ultrasound-guided compression of femoral pseudoaneurysm: an audit of practice.

OBJECTIVE: To audit the practice of ultrasound-guided compression of femoral pseudoaneurysm in a specialist cardiac hospital. BACKGROUND: Femoral pseudoaneurysm is an important complication of invasive cardiac procedures. This may require surgical repair but more recently ultrasound-guided compression for ablating pseudoaneurysms has been described. We investigated the success of such a procedure. METHODS AND RESULTS: In a 26-month period, 56 patients were referred for ultrasound scanning to exclude the formation of a femoral pseudoaneurysm following transfemoral cardiac procedures. During this period, 5756 diagnostic cardiac catherisations and 1165 coronary angioplasties were performed in our hospital (total of 6921 procedures). Of the 56 patients, 20 patients (0.3% of 6921) were found to have a pseudoaneurysm. Ultrasound-guided compression was attempted in 11 patients and was successful in 7 patients (64%). Of the patients who had failed ultrasound-guided compression, 2 proceeded to surgical closure and 2 were treated conservatively with compression stockings to facilitate thrombosis of the pseudoaneurysm. Of those who did not have an attempted ultrasound-guided compression of the pseudoaneurysm (n=9), a conservative approach consisting of resting the leg was adopted to facilitate spontaneous thrombosis of the pseudoaneurysm; repeat ultrasound scanning was needed for follow-up and 1 patient required surgical closure in this group. CONCLUSIONS: In patients with a femoral pseudoaneurysm following an invasive cardiac procedure, ultrasound-guided compression may be useful as an immediate step to ablate the pseudoaneurysm. This avoids either prolonged leg rest and repeated ultrasound scanning or surgical intervention. However, ultrasound-guided compression is not always successful; in these patients, a period of conservative management with repeat ultrasound scanning is appropriate to allow for the possible spontaneous thrombosis of the pseudoaneurysm. Surgical closure is needed in those patients whose pseudoaneurysm is enlarging, painful or remain patent.

Adult↗

PubMed1998

Amlodipine versus diltiazem as additional antianginal treatment to atenolol. Centralised European Studies in Angina Research (CESAR) Investigators.

The antianginal efficacy and tolerability of amlodipine and diltiazem were compared in a double-blind randomized trial of 97 patients with angina resistant to atenolol alone. Both amlodipine and diltiazem significantly reduced the frequency of angina attacks (p <0.001) and glyceryl trinitrate consumption (p <0.05 to p <0.01). During Holter monitoring, both treatments reduced the overall frequency of ambulatory myocardial ischemia, although changes did not reach statistical significance. Exercise test parameters (total exercise time, time to angina, time to ST depression, and maximum ST depression) tended to improve with both treatments, but changes did not achieve statistical significance relative to baseline or to each other. Both drugs were generally well tolerated. Adverse events occurred in 15 patients in the amlodipine group (30%) and in 17 patients in the diltiazem group (36%), but patients taking diltiazem reported almost twice as many adverse events (30) patients taking amlodipine (18). Quality of life, as assessed by total Nottingham Health Profile Scores, was not significantly different between treatments. The addition of either once-daily amlodipine or twice-daily sustained release diltiazem improved symptoms in patients with angina resistant to atenolol alone, but diltiazem was associated with more frequent and more serious adverse events.

Adrenergic beta-Antagonists↗

PubMed1998

Family history and risk of osteoporotic fracture. Study of Osteoporotic Fractures Research Group.

The importance of family history of fractures as a risk factor for fractures is unclear. The aim of this study was to test the hypothesis that family history of fracture increased a woman's risk of hip, wrist and other osteoporotic fracture and determine whether the influence of family history is independent of low bone density. We tested this hypothesis in a prospective study of 9704 Caucasian women, age 65 years or older, by assessing family history and bone density of the radius and calcaneus at baseline; 7963 women had femoral bone density measurements two years later. Fractures occurring during an average of 7.1 years of follow-up since baseline and 5.2 years since the second examination were confirmed by radiographic report. After adjusting for age, risk of hip fracture was increased in those with a maternal (1.48; 95% CI = 1.03-2.11); sister's (1.83; 1.20-2.80) or brother's history of hip fracture (2.26; 1.16-4.42). Risk of wrist fracture was increased by maternal (1.52; 1.10-2.11) and paternal (2.41; 1.14-5.07) history of wrist fracture. Adjustment for bone density did not consistently and substantially affect the strength of the associations. Family history of hip fracture was not associated with an increased risk of wrist fracture and family history of wrist fracture did not increase the risk of hip fracture. We conclude that family history is an important risk factor for fracture that may act, at least in part, through means besides bone density. Furthermore, the effect of family history is not a general but site-specific predisposition to fracture.

Aged↗

PubMed1998

Long-term prognosis in unstable angina. The importance of early risk stratification using continuous ST segment monitoring.

AIMS: To assess the ability of clinical characteristics, admission ECG and continuous ST segment monitoring in determining long-term prognosis in unstable angina. METHODS: Two hundred and twelve patients with unstable angina (mean age 59 years), presenting within 24 h of an acute episode of angina were recruited at three hospitals and treated with standardized medical therapy. All patients kept chest pain charts and underwent ST segment monitoring for 48 h. The occurrence of death, myocardial infarction, and need for revascularization was assessed over a median follow-up of 2.6 years. RESULTS: The risk of death of myocardial infarction was greatest in the first 6-8 weeks after admission. Admission ECG ST depression and the presence of transient ischaemia predicted increased risk of subsequent death or myocardial infarction, whereas a normal ECG predicted a good prognosis. In 14 patients, ST segment monitoring provided the only evidence of recurrent ischaemia, and 72% of this group suffered an adverse event. Transient ischaemia and a history of hypertension were the most powerful independent predictors of death or myocardial infarction. CONCLUSIONS: Adverse events in unstable angina occur early after admission and can be predicted by clinical and ECG characteristics, and by the presence of transient ischaemia during ST segment monitoring. Risk stratification by these simple assessments can identify patients with unstable angina at high risk.

Adult↗

PubMed1998

Mobility after hip fracture predicts health outcomes.

OBJECTIVES: Balance and gait are essential to physical functioning and the performance of activities of daily living. The objective of this study was to determine the predictive value of a balance and gait test on subsequent mortality, morbidity, and healthcare utilization among older hip fracture patients. DESIGN: A prospective study of hip fracture recovery. SETTING: Patients with a new hip fracture admitted from the community to one of eight Baltimore hospitals and followed in their homes for 2 years postfracture. PARTICIPANTS: A total of 306 patients with hip fracture, 65 years of age and older, who completed a gait and balance assessment at 2 months postfracture. MEASUREMENTS: The relationship between gait and balance test performance at 2 months postfracture and mortality, physician visits, rehospitalizations, nursing home placement, and falls up to 24 months postfracture was assessed by Cox proportional hazards and least squares regression. RESULTS: After adjusting for age, sex, race, and comorbidity, the balance score and the summary mobility score predicted mortality. A 17% increase in the risk of mortality was demonstrated for each unit decrease in the balance score (range 0-17), and a 10% increase was demonstrated for each decrease in the summary score (range 0-26). Unsteady balance during immediate standing, turning, sitting down, and rising from a chair were associated significantly with increased mortality. Poor balance, but not poor gait, was associated with an increase in hospitalizations up to 24 months postfracture. Both poor balance and poor gait were associated with nursing home placement, with 20% and 17% increased odds, respectively. Mobility did not predict future physician visits or falls. CONCLUSIONS: These findings demonstrate that balance and gait are predictive of future health outcomes for older hip fracture patients.

Aged↗

PubMed1998

Accuracy of medical records in hip fracture.

OBJECTIVE: To determine the accuracy of diagnoses and procedure codes in medical records for hip fracture patients. DESIGN: A validation sample of hip fracture medical records was used to compare the facesheet data with progress notes, operative reports, and discharge summaries for patients in a prospective study of functional recovery. SETTING: Eight Baltimore hospitals with the highest volume of older hip fracture patients. PATIENTS: Study subjects were 343 community-dwelling patients, 65 years of age and older, admitted to one of eight Baltimore hospitals between January 1990 and June 1991 with a diagnosis of hip fracture. MAIN OUTCOME MEASURES: Facesheet diagnosis codes were compared with admitting notes, discharge summary, and/or progress notes. The abstracted surgical procedure was compared with postoperative radiographs. RESULTS: Excess coding of diagnoses on the hospital facesheet was evident in 12% of charts. In 17% of charts, a complication identified in the chart was not coded on the facesheet. More complications with low severity were omitted. Agreement between the abstractor's procedure review and radiograph readings for arthroplasty was 84%. In 15% of patients, the abstractor coded total arthroplasty when hemiarthroplasty was done. CONCLUSIONS: Discrepancy between the hospital facesheet and the medical record and between the abstracted surgical procedure and radiographs was found for hip fracture patients. This may make findings from health outcomes research relying on administrative databases uncertain and reimbursement inaccurate.

Aged↗

PubMed1998

The surgical treatment of morbid obesity.

Obesity is the second leading cause of preventable death in the United States according to C. Everett Koop, M.D., former Surgeon General of the United States. The use of tobacco is the leading cause, but in the near future, obesity will become the first. Estimates of the percentage of adult Americans who are overweight range from 35% to 50%. Those who are morbidly obese (100 pounds or more overweight), number approximately 8 million. There is no doubt that obesity is a significant public health problem, particularly when its comorbidities are considered: diabetes, hyperlipidemia, hypertension, gastroesophageal reflux, cardiovascular disease, degenerative arthritis, cholelithiasis, respiratory insufficiency, cancer, sleep apnea, and many others. Serious medical problems are usually present in patients with morbid obesity. When significant long-term weight loss is accomplished for these patients, the comorbidities almost always improve or disappear entirely.

Journal Article↗

PubMed1998

Can C reactive protein or troponins T and I predict outcome in patients with intractable unstable angina?

OBJECTIVE: To determine whether a single blood test for the measurement of C reactive protein, or troponin I or T concentrations could be used to stratify patients with intractable unstable angina awaiting transfer for coronary angiography by correlating these values with coronary anatomy and transient myocardial ischaemia. DESIGN: Prospective study. SETTING: Tertiary cardiac unit. PATIENTS: All patients admitted to their local hospital with ischaemic chest pain, uncontrolled by medical treatment, in whom acute myocardial infarction had been excluded by serial measurement of creatine kinase and lack of Q waves on ECG. INTERVENTION: Coronary angiography and ST segment monitoring for 24 hours. MAIN OUTCOME MEASURES: Concentrations of C reactive protein, troponins T and I, coronary anatomy, presence of transient myocardial ischaemia. RESULTS: Median C reactive protein, troponin I, and troponin T concentrations were 17.1 mg/dl (4.8 to 203.9), 0.05 microgram/l (0 to 7.8), and 0.0 microgram/l (0 to 2.51), respectively. Seven patients (10%) had normal coronaries and 14, 20, and 31 had one, two, or three vessel coronary disease, respectively. Nineteen (26%) had transient myocardial ischaemia, 33 (46%) had complex lesion morphology, and six (8%) had intracoronary thrombus. Of the three markers, troponin T alone was higher in patients with multivessel disease (p < 0.05) and in those with transient myocardial ischaemia (p < 0.05), but there was no significant relation between C reactive protein, troponin T or I and lesion morphology or thrombus. CONCLUSIONS: In patients transferred to a tertiary centre with intractable chest pain, C reactive protein and troponin I are not predictive of transient myocardial ischaemia or lesion morphology, both of which are surrogate markers of outcome. Troponin T is, however, raised in patients with multivessel disease or transient myocardial ischaemia. These serum protein assays cannot be used to stratify the risk of patients with unstable angina who are awaiting transfer to the tertiary centre.

Adult↗

PubMed1998

Current roles and future possibilities for low-molecular-weight heparins in unstable angina.

Intravenous unfractionated heparin (UFH) is associated with several limitations, including short duration of action, poor bioavailability, unpredictable anticoagulant response, a risk of heparin-induced thrombocytopenia (HIT), and disease reactivation following early discontinuation. Because of these limitations, there is interest in the development of newer antithrombotic strategies. Low-molecular-weight heparins (LMWHs) offer potential benefits over standard heparin and allow the opportunity for subcutaneous self-administration for longer periods. In the acute phase of unstable angina, LMWHs have been shown to be superior to placebo and at least as effective as UFH in reducing death, myocardial infarction and recurrent angina. Trials of longer-term therapy with LMWHs are in progress. Although animal studies have suggested that LMWHs, by reducing neo-intimal proliferation, may prevent restenosis following coronary angioplasty, clinical trials have been disappointing. However, an initial study with the LMWH enoxaparin (Lovenox/Clexane) and ticlopidine after elective stenting (ENTICES) showed a reduction in stent thrombosis and ischaemic events. This has led to a further trial of antiplatelet therapy versus Lovenox plus antiplatelet therapy for patients with an increased risk of stent thrombosis (ATLAST). Further studies are assessing the role of diffusion and pressure-driven and mechanical devices to deliver high and sustained local intravascular concentrations of heparin.

Angina, Unstable↗

PubMed1998

The European trial on reduction of cardiac events with perindopril in stable coronary artery disease (EUROPA).

BACKGROUND: Angiotensin-converting enzyme (ACE) inhibitors have an accepted place in the treatment of hypertension and heart failure. However, at present they have no specific role in the prevention or treatment of coronary artery disease: evidence from animal experiments and some of the large ACE inhibitor cardiac studies makes this effect well worth testing. OBJECTIVE: The objective of EUROPA is to assess the effects of perindopril (an ACE inhibitor) on outcome in patients with stable coronary artery disease, but no clinical heart failure. METHODS: This is a double-blind, placebo-controlled, multicentre study with a duration of 3.5 years. It is proposed to recruit 10500 patients from 24 countries in Europe. The primary end-point is a combined one: total mortality, non-fatal acute myocardial infarction, unstable angina pectoris and cardiac arrest with successful resuscitation are included; the outcome is studied in patients with proven coronary artery disease and no clinical heart failure. Secondary end-points consist of these events individually calculated. The first patient was recruited in October 1997, and it is planned to finish recruitment by the end of 1998.

Adolescent↗

PubMed1998

EUROPA substudies, confirmation of pathophysiological concepts. European trial on reduction of cardiac events with perindopril in stable coronary artery disease.

In patients with coronary disease, ACE inhibitors may improve endothelial function in the coronary arteries as well as peripheral arteries, and may have anti-proliferative effects which might result in retardation of progression of coronary artery disease. In order to verify these pathophysiological concepts, a series of substudies will be conducted as part of the EUROPA programme. Angiographic and intravascular ultrasound examination of coronary arteries will be performed in approximately 400 patients before and after 3 years' treatment with either perindopril or placebo, in order to assess progression and possible regression of coronary lesions. B-mode ultrasonography of the brachial artery will be used as a model for changes in the coronary arteries, to assess endothelial function in response to ischaemia (reactive hyperaemia) and to vasoconstriction (cold pressor test). Three hundred patients will be investigated before and at different intervals after initiation of study treatment. In addition genetic characterization will be performed of patients participating in EUROPA in order to assess whether specific genotypes do respond more or less favourably to perindopril. In addition, the effect of perindopril will be investigated in patients with diabetes type II, since ACE inhibition in such patients may improve microvascular function and renal function. Integration of these substudies, as well as detailed analysis of other specific subgroups in EUROPA, will help us understand the effects of treatment with perindopril in patients with stable coronary artery disease.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1997

Proxy reporting in five areas of functional status. Comparison with self-reports and observations of performance.

Proxy ratings of functional status were compared with subject self-reports in five domains relevant to the study of older persons and with observations of subject performance in two areas (physical and instrumental functioning). Data were derived from 233 proxy-subject pairs evaluated in a prospective study of hip fracture patients aged 65 years or more in Baltimore, Maryland (1990-1991). Agreement between proxy and subject reports was highest for a summary measure of instrumental functioning and lowest for a measure of depression. Proxies tended to report more disability than did subjects, although bias varied by function. Patterns of agreement for proxy reports versus observations of performance compared with patterns for proxy reports versus subject reports were lower for measures of instrumental functioning, and bias was generally more extreme for instrumental and physical functioning measures. The authors conclude that agreement and bias differ by functional domain, by the way summary measures are created and scored, and by the criterion against which proxy reports are compared.

Activities of Daily Living↗

PubMed1997

Pathophysiology of transient myocardial ischemia in acute coronary syndromes. Characterization by continuous ST-segment monitoring.

BACKGROUND: Transient ischemia in stable coronary disease peaks in the morning, reflecting increased myocardial oxygen demand and coronary vasomotor tone after walking. In acute coronary syndromes, however, ischemia may result from transient thrombus formation or coronary spasm at the site of a ruptured plaque. We report on the pathophysiological mechanisms underlying transient ischemia in acute coronary syndromes despite optimal therapy, on the basis of analysis of heart rate changes preceding ischemia and its circadian variation. METHODS AND RESULTS: Two hundred fifty-six patients with unstable angina or non-Q-wave myocardial infarction underwent continuous ST-segment monitoring for 48 hours while receiving maximal medical therapy. All ischemic episodes were characterized by their timing, duration, association with pain, and heart rate changes before the onset of ischemia. During 10,629 hours of monitoring, 44 patients (17.2%) had 176 episodes of transient ischemia. The mean heart rate at onset of ischemia was 68 +/- 12.8 bpm, and > 55% of ischemic episodes were not preceded by a significant increase in heart rate. Ischemic activity had a single nocturnal peak, with 64% of all episodes occurring between 10 PM and 8 AM, this nocturnal preponderance being evident for episodes with or without a preceding increase in heart rate. The characteristics and timing of transient ischemia were similar in unstable angina and non-Q-wave myocardial infarction, but transient ischemia was more frequent (27.3% versus 15.1%; P < .05) and prolonged (median, 20 versus 13.5 minutes; P < .01) in non-Q-wave myocardial infarction. CONCLUSIONS: In acute coronary syndromes, transient ischemia has a low threshold, occurs predominantly without an increase in myocardial oxygen demand, and is present mainly at night rather than in the morning. These findings in patients receiving maximal medical therapy suggest significant pathophysiological differences underlying transient ischemia compared with stable coronary disease.

Acute Disease↗

PubMed1997

Asynchronous left ventricular wall motion in unstable angina.

The objective of the study was to assess the nature of left ventricular wall motion disturbances in patients with unstable angina and the relative contributions of the severity of symptoms and the severity of coronary artery disease (CAD) to their genesis. A prospective examination was performed on 30 patients with unstable angina (UA) with triple CAD, 34 matched patients with chronic stable angina (CSA) (20 with triple CAD and 14 with isolated left anterior descending (LAD) artery disease), and compared to 21 normals. LV cavity size was normal in all three groups. Twenty-two of 30 patients with UA had marked (>3 mm) abnormal long axis shortening during isovolumic relaxation time (IVRT), 65% of LV sites being abnormal. In CSA, minor (<3 mm) shortening during IVRT occurred in 7 patients with triple CAD, and in 5 with LAD disease, with 12% of LV sites involved in both groups, P<0.001 vs. UA. The incidence of other long axis abnormalities, including reduced extent and peak rate of shortening and lengthening as well as the delay in the onset of shortening and lengthening was increased between patients with CSA and triple CAD compared with LAD but not between the two groups of patients with triple CAD, CSA and UA. Transmitral E/A ratio was also reduced in the two groups with triple vessel disease, CSA and UA. Thus, the incidence of minor long axis abnormalities is similar in CSA and UA and is related to the severity of CAD. However, abnormal shortening during IVRT is more severe and generalised in UA but not in CSA with triple vessel disease. We suggest that these abnormalities of wall motion bear a close relation to the development of instability within the setting of CAD.

Aged↗

PubMed1997

How European cardiologists perceive the role of calcium antagonists in the treatment of stable angina.

Some 100 European cardiologists discussed calcium antagonists' role in the management of stable angina. Sixty-two percent of those involved used calcium antagonists rather than beta-blockers as first line therapy; 46% were prepared to use calcium antagonists in patients who had had a myocardial infarction more than 6 months previously. Only one tenth would use calcium antagonists in angina patients with left ventricular dysfunction. There was a broad preference for the use of heart rate-moderating calcium antagonists in most forms of stable angina. The discussions also underlined the diagnostic importance of angiography, exercise testing and lipid profile analysis.

Adrenergic beta-Antagonists↗

PubMed1997

An intergenerational program for persons with dementia using Montessori methods.

An intergenerational program bringing together older adults with dementia and preschool children in one-on-one interactions is described. Montessori activities, which have strong ties to physical and occupational therapy, as well as to theories of developmental and cognitive psychology, are used as the context for these interactions. Our experience indicates that older adults with dementia can still serve as effective mentors and teachers to children in an appropriately structured setting.

Aged↗