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Biomedical subjects

J R Hampton

Publications and source records attributed to J R Hampton.

At least 73 records · Page 4Linked to original sources
PubMed1994

Methods of establishing criteria for purchasing coronary angiography in the investigation of chest pain.

BACKGROUND: Purchasers may now define how many clinical procedures they wish to buy. In the investigation of chest pain, coronary angiography provides a definitive diagnosis. In clinical practice, the use of coronary angiography varies, so purchasers may choose the sort of service they wish to buy. We reviewed the extent of variation in the investigation of patients in the Trent Region and present a system for establishing criteria for the purchase of coronary angiography. METHODS: Three studies are presented, based on patients referred to the three referral centres in the Trent Region. First, the appropriateness for investigation, defined as benefit outweighing risk, is determined by expert panel; second, an audit of patients referred for coronary angiography is presented; and third, the likelihood or probability of significant coronary disease is assessed by application of a logistic regression model. RESULTS: According to the panel criteria, 27 per cent of patients in one centre were judged inappropriate for coronary angiography, 28 per cent in the second centre and 10 per cent in the third. When referred for angiography, extent of anti-anginal medication, symptom severity, use of exercise testing, and result of and planned management after angiography varied widely among centres. The likelihood of significant coronary artery disease could be predicted in 86 per cent of patients. CONCLUSIONS: Variation in clinical practice does not make the purchasers' task easy. Based upon these studies and clinical trials of coronary artery bypass surgery and coronary angioplasty, we present potential performance indicators which may form the basis of contracts or be used as audit measures.

Coronary Angiography↗
PubMed1994

Implication of prescriptions for nitrates: 7 year follow up of patients treated for angina in general practice.

OBJECTIVE: To determine the demand placed on local cardiological services by patients prescribed nitrates for ischaemic heart disease. DESIGN: A follow up study of a cohort of patients identified in 1985. SETTING: Nottingham Health District. PATIENTS: Four hundred and ninety nine patients prescribed nitrates in 1985 for presumed ischaemic heart disease. MAIN OUTCOME MEASURES: Referral to medical outpatients, admittance to hospital with chest pain, cardiological investigations, and mortality. RESULTS: Over the seven year period 26% of patients were admitted urgently with chest pain and 15% were referred to the medical outpatient department--a referral rate of 6% a year. 4% of patients had an exercise test and 6% a coronary angiogram. The death rate was 6% a year and a higher proportion died of cardiovascular causes than would be expected in the general population. CONCLUSIONS: Prescription of nitrate is useful in the determination of the prevalence of ischaemic heart disease. Most patients with angina are still treated within the community, and the rate of specialist investigation remains low.

Adult↗
PubMed1994

Variations in the use of coronary angiography in three cities in the Trent Region.

OBJECTIVE: To establish the characteristics of patients referred for coronary angiography and the outcome of investigation. DESIGN: Prospective study. SETTING: Three regional referral centres at Sheffield, Leicester, and Nottingham. PATIENTS: All patients referred for investigation from 1 July 1988 to 30 June 1989. INTERVENTIONS: Coronary angiography for suspected ischaemic heart disease. MAIN OUTCOME MEASURES: Site and extent of coronary artery disease at coronary angiography and subsequent intervention. RESULTS: There was a range of clinical activity with a trend towards symptomatic control in Nottingham where patients tended to have more severe angina of long duration and extensive drug treatment. Important coronary lesions were often found and most patients needed coronary artery bypass surgery or angioplasty. In Leicester and Sheffield, where angiography was used prognostically, patients tended to have mild angina of shorter duration and less extensive medical treatment; significant coronary disease was often found but fewer patients were recommended for further intervention. CONCLUSIONS: Referral for coronary angiography seems to reflect philosophical differences among the referring physicians. Referring patients late in the disease process ensures that most have a subsequent intervention but the benefits of revascularisation may be denied to those with mild symptoms but extensive coronary disease.

Adult↗
PubMed1994

Evidence of inadequate investigation and treatment of patients with heart failure.

OBJECTIVE: To determine the referral rates to hospital and level of investigation of patients with heart failure, and to assess whether they are receiving optimum management. DESIGN: A retrospective survey. SETTING: Nottingham Health District. PATIENTS: 505 patients receiving loop diuretic treatment prescribed by their general practitioner. MAIN OUTCOME MEASURES: Referral to hospital as an inpatient or outpatient for assessment of assumed cardiac failure; investigations--electrocardiography, chest radiography, and echocardiography; treatment with angiotensin converting enzyme inhibitors. RESULTS: Only 56% of patients prescribed loop diuretics fulfilled the diagnostic criteria for heart failure. Of these, 74% had been referred to hospital, of whom 80% had had an electrocardiograph, 75% a chest radiograph, but only 31% an echocardiogram. Only 17% of patients with heart failure were being treated with angiotensin converting enzyme inhibitors in conjunction with loop diuretics. CONCLUSIONS: Patients with heart failure in the Nottingham Health District are not being adequately investigated or receiving the optimum treatment.

Aged↗
PubMed1994

Choosing the right beta-blocker. A guide to selection.

beta-Blockers have been in clinical use for 30 years, and have an accepted role in (among others) the treatment of high blood pressure, the secondary prevention of myocardial infarction and the treatment of arrhythmias. Their place in the treatment of heart failure is currently under investigation. The drugs available in the 1970s and early 1980s were subjected to intense investigation. A new generation of beta-blockers, including some such as carvedilol and bucindolol, with vasodilating properties, is now appearing. As yet these later agents have not been the subject of large clinical trials. Clinical practice involves the treatment of individual patients with defined dosages of particular drugs. It is, therefore, not acceptable to base practice on theories derived from the clinical pharmacology of a particular drug, on the results of small trials or on a meta-analysis of results from a number of trials that were individually inadequate. Clinical practice must follow the results of large-scale trials in defined populations. The major trials in hypertension, myocardial infarction, arrhythmias and heart failure provide the best evidence for the use of individual beta-blockers in each of these clinical situations. In patients with high blood pressure, beta-blockers do not seem to have any particular advantage over other hypotensive agents. In myocardial infarction, relatively late use of a beta-blocker undoubtedly reduces fatality, though the value of early treatment is less clear. beta-Blockers are not powerful antiarrhythmics, but they do appear to prevent sudden death. Their possible role in heart failure is perhaps the most interesting current field of beta-blocker research. There are very few comparative studies of beta-blockers, and it is difficult to make precise recommendations. None of the new generation of beta-blockers has yet been used in a trial that is large enough trial for any of them to be accepted for routine use in preference to older drugs. The use of individual beta-blockers, as with any drug, should follow the results of clinical trials. Propranolol and atenolol have been studied most intensely in hypertension. For secondary prevention of myocardial infarction, the evidence is best for timolol. Sotalol is probably the best antiarrhythmic among the beta-blockers. Whether any individual beta-blocker is best for heart failure remains to be seen.

Adrenergic beta-Antagonists↗
PubMed1993

The effect of lorcainide on arrhythmias and survival in patients with acute myocardial infarction: an example of publication bias.

Ninety-five patients with suspected acute myocardial infarction were randomly allocated on admission to hospital on a double blind basis to treatment with lorcainide, a Class 1C anti-arrhythmic drug, or matching placebo. Treatment was continued for 6 weeks. Twenty-four-hour ECG tape recordings were made immediately on admission, on the sixth or seventh day after admission, and again just before the end of the treatment period. Lorcainide was shown to be an effective anti-arrhythmic agent. The study was not designed to evaluate the effect of lorcainide on survival, but there were nine deaths among the 49 patients treated with lorcainide compared with only one in the patients given placebo. These findings are consistent with the results of the First and Second Cardiac Arrhythmia Suppression trials (CAST and CAST-II). This study was carried out in 1980 but was not published at the time: it now provides an interesting example of 'publication bias'.

Anti-Arrhythmia Agents↗
PubMed1993

Impact of hospital thrombolysis policy on out-of-hospital response to suspected myocardial infarction.

The treatment of acute myocardial infarction changed when several trials reported that thrombolytic agents given within a few hours of infarction improved outcome. We present data from the Nottingham Heart Attack Register comparing 1982-84, when thrombolysis was not available, and 1989-90, when it was hospital policy to give thrombolysis to all patients who arrived within 6 hours of the onset of symptoms, in the absence of a specific contraindication. The number of patients referred with symptoms suggestive of acute myocardial infarction increased by 75% from 1982 to 1990; a diagnosis of "possible infarction" was made in about half of all patients in 1982-84 and 23% in 1989-90. Our current thrombolytic policy has had little impact on patient and general practitioner (GP) behaviour. The GP was contacted by most patients. The median time between the onset of a patient's symptoms and admission to hospital when the GP was involved was 229 min in 1982-84 and 210 min in 1989-90; when he was not involved in arranging the admission median times to admission were 89 min and 75 min, respectively. By 6 hours from symptom onset, 60% of patients had been admitted; by 12 hours, about 70% were in hospital and by 24 hours, 80%. Of 7855 patients admitted with suspected acute myocardial infarction in 1989-90, 4465 were admitted within 6 hours of symptom onset. Of these, 736 (16%) patients received a thrombolytic drug. 389 (9%) patients had a specific, documented contraindication to thrombolysis. Although we estimate that the policy has saved about 8 lives per year, it is not surprising that there has been no improvement in overall case fatality after myocardial infarction.

Emergency Medical Services↗
PubMed1993

Postinfarct heart failure: role of diuretic therapy.

There can be no doubt that ACE inhibitors prolong survival in patients with a low ejection fraction. There is no evidence whether or not diuretics have the same effect. The pathophysiology of asymptomatic patients with poor left ventricular function differs from that of patients with the clinical syndrome of heart failure, and different treatments may well be needed. Diuretics still have a crucial role in the relief of symptoms.

Cardiac Output, Low↗
PubMed1993

The appropriateness of the use of cardiovascular procedures. British versus U.S. perspectives.

To determine whether patients are less likely to receive an inappropriate procedure in countries that devote fewer resources to health care than does the United States, we studied how appropriately coronary angiography and coronary artery bypass surgery were performed in the Trent region of the United Kingdom. The medical records of 320 patients who underwent coronary angiography and 319 who underwent coronary artery bypass surgery in 1987 and 1988 were randomly selected for review. Despite the United Kingdom's more limited use of coronary angiography and coronary artery bypass surgery, a substantial proportion were still performed for less than appropriate reasons, by both U.S. and U.K. criteria. Merely reducing the rate of use of these procedures will not be sufficient to eliminate such inappropriate use.

Aged↗
PubMed1993

The effect of the angiotensin converting enzyme inhibitor, enalapril, on exercise tolerance and abnormalities of limb blood flow and respiratory function in patients with severe heart failure.

Ten patients with severe (NYHAIII) heart failure were compared with 10 age-matched healthy subjects in terms of oxygen uptake and minute ventilation at rest and during exercise and calf and forearm blood flow measured by venous occlusion plethysmography at rest and after a standardized exercise test. Patients performed a symptom-limited treadmill exercise test and were then treated with enalapril for 5 weeks; the various measurements were repeated at weekly intervals. Oxygen consumption (VO2) at rest was similar in the patients and controls. During exercise, patients VO2 tended to be lower at each workload, but this was not affected by enalapril treatment. Minute ventilation was higher at rest and at each exercise stage in the patients than in the control subjects, and this was significantly reduced by enalapril treatment. Compared with the controls (2.94 +/- 0.10 and 2.93 +/- 0.20 ml.100 ml-1.min-1) forearm and calf blood flow measured by venous occlusion plethysmography was reduced at rest in the patients (1.34 +/- 0.18 and 1.24 +/- 0.11 ml.100 ml-1.min-1). but was significantly increased by enalapril treatment (1.73 +/- 0.15 and 1.60 +/- 0.16 ml.100 ml-1.min-1). Submaximal leg exercise to a fixed VO2 showed attenuation of the normal vasoconstriction in the forearm and vasodilatation of the calf; enalapril treatment changed these responses significantly towards normal but a marked abnormality of flow pattern persisted.

Aged↗
PubMed1993

Sensitivity and specificity of the initial working diagnosis in acute myocardial infarction: implications for thrombolysis.

Diagnosing acute myocardial infarction promptly allows all eligible patients to be considered for thrombolysis. Objective evidence from the first electrocardiograph may be inadequate and often the doctor must base his immediate management on limited information; an incorrect initial working diagnosis might deny some patients the benefits of thrombolysis or expose others to inappropriate, expensive and potentially harmful treatment. We were interested to find out how accurate our junior doctors were in their assessment of patients admitted with a suspected MI. All patients entered onto the Nottingham Heart Attack Register admitted with suspected acute MI from 1982 to 1986 and 1989 were identified. The initial working diagnosis on admission was obtained from the patient case record. A final diagnosis was assigned according to strictly defined criteria using 'cardiac' enzyme and electrocardiographic results. Sensitivity and specificity of the initial working diagnosis was calculated. Using the initial working diagnosis as a 'screening' test, we found that, while our doctors successfully identified patients with myocardial ischaemia, they were less good at recognizing acute MI--an admission diagnosis of 'MI' carried a sensitivity of 55% and specificity of 88%. This may explain the low utilization of thrombolysis in the Nottingham hospitals. In the first full year since thrombolysis became available, we estimated that we might have exposed 65 patients to the risks of thrombolysis inappropriately and we might have missed treating 244 patients.

Diagnosis, Differential↗
PubMed1993

Significance of smoking in patients receiving thrombolytic therapy for acute myocardial infarction. Experience gleaned from the International Tissue Plasminogen Activator/Streptokinase Mortality Trial.

BACKGROUND: Despite the fact that smoking is a well-established risk factor for the development of coronary artery disease, some investigators have noted that hospital mortality after acute myocardial infarction is lower in patients who smoke than in nonsmoking patients. To evaluate the association of smoking with mortality during hospitalization after thrombolytic therapy and 6 months afterward, we analyzed the results of the International Tissue Plasminogen Activator/Streptokinase Mortality Trial. METHODS AND RESULTS: Patients were divided into three groups: nonsmokers (those who never smoked), ex-smokers, and active smokers. Multivariate and univariate comparisons were made with respect to baseline characteristics and clinical outcome. There were 2,366 nonsmokers, 2,244 ex-smokers, and 3,649 active smokers. The baseline characteristics of nonsmoking patients differed significantly from the ex-smokers and active smokers. The nonsmoking group included more women than the ex-smokers or active smokers (45% versus 10.6% and 17.6%, respectively), was older (67 +/- 10 years versus 64 +/- 10 years and 58 +/- 11 years), had a higher rate of diabetes mellitus (16.3% versus 11.1% and 7.5%), and had a worse Killip class at admission. Nonsmoking patients and ex-smokers experienced more in-hospital reinfarction than active smokers (4.7% and 5% versus 2.7%, p < 0.0001, respectively). Nonsmokers experienced more in-hospital shock than the ex-smokers or active smokers (9.2% versus 6.4% and 5.8%, p < 0.0001), stroke (1.9% versus 1.8% and 0.8%, p < 0.0001), and bleeding (7.2% versus 6.5% and 4.4%, p < 0.0001). They also experienced a higher in-hospital and 6-month mortality (12.8% and 17.6%) than ex-smokers (8.2% and 12.1%) or active smokers (5.4% and 7.8%) (p < 0.0001). A multivariate analysis accounting for all baseline characteristics demonstrated a significant association between nonsmoking and increased hospital mortality, with an odds ratio of 1.42 (confidence limits, 1.15-1.72). Among active smokers, there was a nonsignificant trend for mortality rates to decrease with increasing numbers of cigarettes smoked per day. CONCLUSIONS: This retrospective analysis indicates that smokers receiving thrombolytic therapy after acute myocardial infarction have significantly better hospital and 6-month outcome than nonsmokers or ex-smokers. However, smokers sustained their infarction at a significantly earlier age than nonsmokers, and strenuous efforts should continue to be made to decrease the incidence of new and continued smoking.

Aged↗
PubMed1993

After correcting for worse baseline characteristics, women treated with thrombolytic therapy for acute myocardial infarction have the same mortality and morbidity as men except for a higher incidence of hemorrhagic stroke. The Investigators of the International Tissue Plasminogen Activator/Streptokinase Mortality Study.

BACKGROUND: In the prethrombolytic era, women with myocardial infarction were reported to have a worse outcome than men. This analysis evaluates the association of sex with morbidity and mortality after thrombolytic therapy. METHODS AND RESULTS: Data were analyzed from 8261 of the 8387 randomized patients with acute myocardial infarction who received thrombolytic therapy in the International Tissue Plasminogen Activator/Streptokinase Mortality Study (baseline data were missing for 126 patients) and were followed for 6 months. Women made up 23% (n = 1944) of the study population. Baseline characteristics were worse in women: they were 6 years older, were more likely to have a history of previous infarction (P < .01), antecedent angina (P < .01), hypertension (P < .0001), or diabetes (P < .0001); were in a higher Killip class on admission (P < .0002); and received thrombolytic therapy 18 minutes later than men (P < .0001). Fewer women were smokers (P < .0001). Women had a higher hospital (12.1% versus 7.2%, P < .0001) and 6-month mortality (16.6% versus 10.4%, P < .0001) and were more likely to develop cardiogenic shock (9.1% versus 6.3%, P < .0001), bleeding (7.2% versus 5.3%, P < .01), and hemorrhagic (1% versus 0.3%, P < .001) or total stroke (2.2% versus 1.1%, P < .0001) during hospitalization. Reinfarction rates and requirement for angioplasty or surgery did not differ. After correction for worse baseline characteristics, women had similar morbidity and mortality apart from a significantly higher incidence of hemorrhagic stroke, which remained significant even after accounting for weight and treatment allocation (odds ratio, 2.90; P < .01). CONCLUSIONS: After thrombolytic therapy for acute myocardial infarction, women have similar morbidity and mortality to men but suffer from a higher incidence of hemorrhagic stroke.

Aged↗
PubMed1992

A comparison of the effects of captopril and flosequinan in patients with severe heart failure.

Angiotensin converting enzyme inhibitors have greatly improved the treatment of patients with chronic heart failure but they are not effective in all patients, and their use may be limited by side effects. There is, therefore, a need to investigate new drugs and to compare their efficacy with angiotensin converting enzyme inhibitors. Flosequinan is a new direct-acting vasodilator that has been shown to be effective in placebo-controlled studies. Patients with chronic heart failure in NYHA classes II or III who remained symptomatic despite at least 80 mg of frusemide daily were recruited from two centers. Following a single-blind placebo run-in period, the patients were randomized double blind to either the addition of captopril or flosequinan for 6 weeks. Following a further 2-week placebo washout period, they were then given the alternative treatment. Symptom-limited treadmill exercise times, scores of perceived exertion, and corridor walk tests were measured at two weekly intervals during the study. Twenty-five patients entered the study, 16 of whom completed without a change in diuretic dose. Five patients were withdrawn while taking captopril and two while taking flosequinan; two were withdrawn during the placebo washout period. For those patients who completed the study, flosequinan increased treadmill exercise tolerance from a mean (SEM) placebo time of 11.5 (1.0) minutes by 2.4 (0.6) (p = 0.0002) and captopril from 12.0 (0.8) minutes by 1.2 (0.6) minutes (p = 0.08). Comparison of the other measures of efficacy revealed no difference between the groups. In this short-term study flosequinan appeared to be equal in efficacy to captopril.

Aged↗
PubMed1992

Comparative efficacy of diuretics: benefit versus risk: results of clinical trials.

Although several large trials have been conducted with the aim of establishing the need for, and the best approach to, the treatment of hypertension, none have specifically addressed the question of the best use of diuretics. Analysing the trials to obtain specific answers about diuretics is therefore difficult, and particularly so because of differences in trial design and in the medications used. Comparisons between active treatment and no therapy have tended to show that active treatment is associated with a significant reduction in the incidence of strokes and a small reduction in myocardial infarction and death. Comparisons of treatment strategies, as opposed to comparisons of particular drugs, are hard to interpret and some conclusions that have been drawn about a harmful effect of diuretics are probably misleading. Trials comparing diuretics and beta-blockers suggest that these types of drug have similar effects on clinical events although the most recently published study suggests that diuretics are more effective than beta-blockers in preventing myocardial infarction. Therefore, it seems that what matters is blood pressure reduction, not the means by which this is achieved. The biochemical effects of diuretics are probably not important, but only one trial has investigated the use of a low dose of diuretics.

Blood Pressure↗
PubMed1992

Management of myocardial infarction: implications for current policy derived from the Nottingham Heart Attack Register.

OBJECTIVE: A register of patients with heart attacks in the Nottingham Health District has been maintained since 1973. Data from 1982 to 1984 inclusive, a period before trials of thrombolytic therapy started in Nottingham, were analysed to provide background information for the introduction of a policy of routine thrombolysis for appropriate patients. DESIGN: Data were collected prospectively on all patients transported to hospital in the Nottingham Health District with suspected myocardial infarction in the years 1982-84 and on patients treated at home during that time. SETTING: Two district general hospitals responsible for all emergency admissions in the health district. PATIENTS: 6712 patients admitted to hospital with suspected myocardial infarction and 1887 patients found dead on arrival at hospital. Approximately 1500 patients in whom a myocardial infarction was suspected were treated at home, but only 125 were identified who had a definite or probable infarction. RESULTS: Among the patients admitted within 24 hours of the onset of symptoms, the median delay from onset to hospital admission was 174 minutes; 25% of patients were admitted within 91 minutes. The only factor that seemed to affect the time taken was the patient's decision to call a general practitioner or an emergency ambulance. If a general practitioner referred the patient to hospital the median delay was 247 minutes, compared with 100 minutes when the patient summoned an ambulance. Ninety three per cent of all patients were transported by ambulance. The median time from the call for the ambulance to hospital arrival was 29 minutes. Once a patient was admitted to hospital, the time to admission and general practitioner involvement seemed relatively unimportant as predictors of outcome. Patients admitted more than nine hours after onset of symptoms with a diagnosis of definite or probable infarction had a poorer outcome than those admitted earlier (in-hospital mortality 22.4% v 13.1%). The fatality rates of those admitted to a coronary care unit or to an ordinary medical ward are similar. CONCLUSION: Although the introduction of thrombolytic therapy has brought with it an increased awareness of the need to minimise any delay in time to admission, it seems that in a predominantly urban area like Nottingham, patients with a suspected heart attack will continue to be admitted to hospital most quickly if an ambulance crew rather than a general practitioner is called. Because the ambulance crew was in contact with such patients for only a short time it seems unlikely that administration of a thrombolytic drug in the ambulance would be helpful.

Coronary Care Units↗