Increased markers of thrombogenesis in chronic atrial fibrillation: effects of warfarin treatment

OBJECTIVE

To determine whether chronic atrial fibrillation is associated with abnormalities in plasma fibrinogen, von Willebrand factor (vWF) (a marker of endothelial disturbance), or fibrin D- dimer (a measure of fibrin turnover); and if so, whether such levels are related to haemodynamic disturbance (enlarged left atrium, poor left ventricular function) or existing treatment with warfarin or aspirin. To investigate the effects of introducing warfarin in patients with atrial fibrillation on fibrinogen and D- dimer levels.

DESIGN

Cross sectional population sample controlled study and longitudinal study of patients undergoing anticoagulation.

SETTING

District general hospital.

SUBJECTS

87 patients (44 men and 43 women of mean (SEM) age 63.0 (1.0)) with chronic atrial fibrillation. At the time of the study, 37 were taking no antithrombotic medication (group 1), 31 were taking warfarin (including two on warfarin and aspirin) (group 2) and 19 were taking aspirin alone (group 3). They were compared with 158 population controls from a random population sample (the second Glasgow monitoring trends and determinants in cardiovascular disease study). As part of clinical treatment warfarin was introduced in 20 patients with chronic atrial fibrillation (14 men and six women of mean (SEM) (range) age 63.9 (2.35 (32-74) years).

RESULTS

Plasma fibrinogen remained significantly increased in patients of group 1 (no antithrombotic medication) compared with that of the population controls (median difference 1.23 g/l; 95% confidence interval (CI) 0.88 to 1.62, P < 0.0001). There was also a significant increase in plasma D-dimer levels (median difference 77 ng/ml; 95% CI 38 to 122, P < 0.01) and vWF (median difference 63 IU/dl; 95% CI 38 to 89, P < 0.0001). There was no significant difference in plasma fibrinogen (median difference 0.14 g/l; 95% CI -0.44 to 0.77, P = 0.65) or vWF (median difference 3.5 IU/dl; 95% CI - 41 to 41, P = not significant in patients of group 2 (warfarin treatment) compared with that of patients in group 1. Levels of D-dimer were significantly lower in group 2 (median difference 90 ng/ml, 95% CI 39 to 150, P < 0.0001) than in group 1. There were no significant differences in plasma fibrinogen (median difference 0.08 g/l; 95% CI - 0.52 to 0.77, P = 0.73), D-dimer (median difference - 34 ng/ml; 95% CI - 114 to 21.0, P = 0.25), or vWF (median difference 2%; 95% CI - 35 to 41, P = not significant) levels between patients of groups 1 and 3. There were no significant correlations between the coagulation indices and left atrial volume or ventricular function. There was a significant positive correlation between plasma fibrin D-dimer and vWF levels in patients of groups 1 and 3 (r = 0.52, P < 0.001). There was a significant reduction in median plasma fibrin D-dimer levels at 2 months after the introduction of warfarin (181 ng/ml v 80 ng/ml, P < 0.001), but no effect on plasma fibrinogen.

CONCLUSIONS

Increased median plasma fibrinogen and vWF levels were found in patients with chronic atrial fibrillation. Plasma D-dimer levels were also increased in patients with chronic atrial fibrillation not receiving warfarin, suggesting increased intravascular thrombogenesis in such patients. Introduction of warfarin normalised circulating fibrin D- dimer levels, suggesting that warfarin treatment was effective in preventing excessive fibrin turnover, consistent with the antithrombotic effects of warfarin. These results suggest three possible thrombotic markers to assess patients with atrial fibrillation who are at high risk of thrombogenesis; D-dimer also merits assessment as a measure of reduction in thrombotic risk in patients receiving warfarin.

Poisoning with antihypertensive drugs: diuretics and potassium supplements

Diuretics are widely prescribed to treat hypertension and oedema. The increasing use of these drugs opens the possibility of an increase in deliberate or accidental self-poisoning. However, experience with overdosage and toxicity with the diuretics remains very limited. In general, supportive therapy by the reduction of gastrointestinal absorption, monitoring of vital signs and the correction of hypertension and electrolyte abnormalities are indicated.

Poisoning with anti-hypertensive drugs: beta-adrenoceptor blocker drugs

The effects of poisoning with beta-blockers may be serious, but are usually self-limiting provided adequate support is given. If there is no evidence of toxicity and the degree of overdose is small, clinical observation may be all that is required. This review examines the cases of overdosage with beta-blockers reported in the literature, the presenting symptoms and possible strategems of management for such patients.

Dietary fat purchasing habits in whites, blacks and Asian peoples in England--implications for heart disease prevention

The mortality and morbidity from coronary heart disease (CHD) is higher in people of South Asian origin than in whites, but is significantly lower in the black (Afro-Caribbean origin) community in the United Kingdom. To investigate whether this may be related to differences in fatty food intake, we performed a questionnaire survey of the weekly food purchasing habits and preparation methods in white, black (Caribbean) and Asian households in Birmingham. We interviewed 224 housewives from three ethnic groups (84 white, 76 black/Afro-Caribbean and 72 Asian). The highest quantity of fat in foods purchased per week was found in the Asian population (median 1409 g/week per person, interquartile range (IQR) 850-1952), which was significantly greater than black subjects, who had the lowest quantity of fat in foods purchased (1012 g/week per person, IQR 835-1388) (Mann-Whitney test:median differences 300.5, 95% C.I. 23.3-600.4, P = 0.029). The median quantity of fat in foods purchased by the white households was intermediate, at 1186 g/week per person (IQR 861-1711). There was a higher quantity of fat in foods purchased in the lower social classes (IV and V) in both the white and Asian populations. Butter, egg and milk consumption was significantly greater in Asians; with ghee consumption almost exclusive amongst this group (98%). Amongst whites and blacks, the commonest food preparation methods were grilling, boiling or poaching; whilst amongst Asians, frying was more common (chi 2 = 81.25, d.f. = 4, P < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Poisoning with anti-hypertensive drugs: calcium antagonists

Calcium antagonists are used increasingly to treat hypertension and other conditions, so the possibility of accidental or deliberate self-poisoning is substantially increased. These drugs account for a high proportion of deaths in cases of poisoning associated with cardiovascular drugs. Most of our present knowledge is with the older calcium antagonists, namely verapamil, nifedipine and diltiazem; newer sustained-release preparations of these drugs may produce serious toxicity in patients who initially appear well. This review discusses the cases reported in the literature, the presenting symptoms and the management of patients with calcium antagonist poisoning.

Alcohol, hypertension, coronary disease and stroke

1. The association between alcohol and hypertension has been recognized for several years. 2. However, it remains a paradox that if alcohol does cause hypertension there is little convincing evidence that alcohol is related to the cardiovascular complications of hypertension such as strokes and heart attacks. The relationship between alcohol and strokes remains inconclusive and there is evidence that moderate alcohol consumption may be protective against heart attacks. 3. It is possible, therefore, that alcohol does not so much cause hypertension, but rather a rapidly reversible rise in blood pressure which does not cause cardiovascular damage. When managing hypertensive patients, however, relevant counselling can bring about a useful fall in blood pressure.

Fibrinogen and cardiovascular disorders

Plasma fibrinogen is involved in blood coagulation and is an important determinant of blood viscosity and hence of blood flow. There is also considerable epidemiological evidence that elevated plasma fibrinogen levels are associated with an increased risk of cardiovascular disorders, including ischaemic heart disease, stroke and other thromboembolic events. This increase in plasma fibrinogen levels may promote a prothrombotic or hypercoagulable state, and may in part explain the risk of stroke and thromboembolism in conditions such as atrial fibrillation and cardiac dysfunction. This review examines the close association between plasma fibrinogen and various cardiovascular disorders.

Factors influencing coronary artery bypass graft patency

Coronary artery bypass surgery is one of the most frequently performed and successful operations in improving quality of life for patients with intractible angina. Unfortunately, there is accumulating evidence that angina will eventually return and consequently an increasing amount of repeat surgery is being undertaken. Subsequent operations have a reduced chance of benefit and many patients are only in early middle age at the time of initial surgery. It is obviously of paramount importance, therefore, to try and maintain graft patency for as long as possible. Various factors such as avoidance of certain surgical techniques, use of the internal mammary artery whenever possible, continued use of aspirin and attention to major risk factors are known to significantly influence graft patency. This review examines these factors in detail and provides practical advice on how to optimize long-term patency.

Have we identified the factors affecting prognosis following coronary artery bypass surgery?

Although coronary artery bypass graft (CABG) surgery has been an established therapeutic alternative for more than 20 years in the palliation of symptoms of ischaemic heart disease, the associated risk factors for subsequent mortality and morbidity in these patients remain unclear. This is pertinent, as CABG surgery does not affect the underlying pathological process and different factors affect the early and late postoperative outcomes. As one objective of CABG surgery is to provide symptomatic relief of angina, it is desirable to identify (and perhaps modify) the factors affecting prognosis and outcome. An awareness of these factors will allow better patient selection and the development of better screening and therapeutic interventions.

A comparative study of risk factors for acute myocardial infarction amongst men of Indo-origin in Trinidad and the UK

A high cardiovascular mortality rate exists amongst people of Indo-origin in Trinidad (third generation migrants) and the United Kingdom (first generation migrants). To investigate the differences in cardiovascular risk factors in these two populations, we surveyed all male patients of Indo-origin with acute myocardial infarction, admitted over a similar 8-week period to the Coronary Care Units of a district general hospital in Birmingham, United Kingdom and a similar hospital in San Fernando, Trinidad. Nineteen patients (mean age 62.2 years +/- S.D. 2.58) were admitted to the Birmingham hospital (UK Group) and fifty-five (mean age 58.1 years +/- S.D. 1.44) to the San Fernando hospital (Trinidad Group). There was no age difference between the groups (P = 0.18). There was a significantly greater proportion of smokers in the Trinidad group (70.9% vs. 63.2%, chi 2 = 4.56, P = 0.03), which also had a higher proportion of diabetics (36.4% vs. 31.6%) and hypertensives (34.5% vs. 31.6%). Mean systolic and diastolic blood pressures were higher in hypertensives from the Trinidad group (Trinidad group 146.6 mmHg +/- 16.9/93.4 mmHg +/- 11.4 vs. UK group 120.8 mmHg +/- 25.4/75.0 mmHg +/- 13.4; P < 0.05). The mean waist to hip ratio was greater in the Trinidad group (1.01 +/- S.D. 0.06) when compared to the UK group (0.95 +/- S.D. 0.05) (paired t-test, P < 0.01). Only six Trinidadian males performed regular exercise and only four of the UK group did so.(ABSTRACT TRUNCATED AT 250 WORDS)

The failure of malignant hypertension to decline: a survey of 24 years' experience in a multiracial population in England

INTRODUCTION

The widespread use of antihypertensive medication and the increasing frequency of diagnosis of mild-to-moderate hypertension should mean that malignant-phase hypertension should be becoming less common, and this trend has been reported elsewhere. No decline in the incidence of malignant hypertension has been apparent in our practice in a district general hospital in a city centre.

OBJECTIVE AND METHODS

To investigate the incidence and mode of clinical presentation of patients presenting with malignant hypertension, we performed a retrospective survey of the number of patients presenting with malignant hypertension to our hospital, over the 24-year period from 1970 to 1993. We identified a total of 242 patients (155 male, 87 female; mean +/- SD age 50.1 +/- 13.3 years) with malignant hypertension.

RESULTS

There were no significant differences in the number of patients presenting each year, the mean age or the presenting systolic and diastolic blood pressures over the period surveyed. At presentation, 131 patients (54.1%) had no previous history of hypertension; 161 (66.5%) were receiving no antihypertensive therapy and only 70 (28.9%) were receiving antihypertensive treatment (with no record of therapy in 11 patients). The most common presenting symptoms included visual disturbance in 62 (25.6%), headaches in 29 (12.0%), headaches and visual disturbance in 24 (9.9%), heart failure in 19 (7.9%), stroke or transient ischaemic attack in 17 (7.0%) and dyspnoea in 13 (5.4%), although 23 patients (9.5%) were asymptomatic. The most common presenting complications were heart failure [27 patients (11.1%)], stroke [23 patients (9.5%)], angina [10 patients (4.1%)], myocardial infarction [nine patients (3.7%)] and chronic renal failure [77 patients (31.7%)]. In the whole group the majority (147 patients, 60.5%) had no complicating clinical features. Primary or essential hypertension was the most common underlying cause in 137 patients (56.4%). Secondary causes of hypertension (mainly renal disease) were identified in 97 patients (39.9%).

CONCLUSION

Our experience suggests that malignant hypertension is still common, with a small proportion of hypertensives presenting each year. In particular, the incidence has failed to decline in Birmingham. The incidence rate in the population served by our hospital is approximately 1-2 cases per 100,000 per year. An awareness of the different presenting clinical features is required to allow better recognition and management of this life-threatening condition.

Abnormalities of rheology and coagulation in hypertension

While the arterial tree is exposed to increased pressure flow, paradoxically the complications of hypertension are mainly thrombotic rather than haemorrhage. Improved techniques have allowed the identification of haemorrheological indices, coagulation factors and markers of arteriolar endothelial and platelet dysfunction which potentially contribute to thrombus formation (thrombogenesis) in patients with hypertension. These factors may be important in the pathogenesis, complications and prognosis of such patients. The purpose of this review is to examine the complex relationship between hypertension and blood rheology, platelets and related components of the coagulation system.

Acute myocardial infarction: a rare complication of the thrombotic tendency in nephrotic syndrome

The association of nephrotic syndrome with a hypercoagulable state and vascular thrombosis is well recognised. We present a case of acute anterior myocardial infarction in a young man with nephrotic syndrome secondary to minimal change glomerulonephritis, in which subsequent coronary angiography showed no evidence of atherosclerotic coronary artery disease and thrombotic occlusion of an otherwise normal left anterior descending coronary artery was the likely cause of presentation.

Hormone replacement therapy and blood pressure in hypertensive women

There remains anxiety about the use of hormone replacement therapy (HRT) in postmenopausal women with hypertension. We therefore conducted a prospective open study of sequential changes in BP in 75 women referred to our hypertension clinic who required HRT for amelioration of menopausal symptoms. There were no significant differences in mean systolic or diastolic BPs following the introduction of HRT over a median follow-up time of 14 months (interquartile range 8-32 months), despite a significant rise in mean body weight for individual patients which was statistically significant at three, nine and 12 months following the introduction of HRT. No differences in BP were seen in relation to type of menopause, ethnic origin, history of previous pregnancy-induced hypertension or the type of HRT preparation used. Our data suggest that HRT is safe in hypertensive women who should not therefore be denied this therapy if they have menopausal symptoms, although careful supervision is necessary.

Cardioversion of atrial fibrillation: how important is a long arrhythmia duration?

A long duration of atrial fibrillation is usually considered as an adverse feature for successful cardioversion of atrial fibrillation and the maintenance of sinus rhythm. This often leads to the exclusion of such patients from being considered for this procedure. We report three patients in whom atrial fibrillation was present for a long duration (one for 2 years, two for 10 years), and successful cardioversion to sinus rhythm was achieved. Proper selection of patients with atrial fibrillation with an understanding of all features predicting a successful outcome will often allow a good result.

Hypertension and the heart

The heart is of great importance in systemic hypertension; it has a role in its pathogenesis but also suffers its consequences. Heart disease is, therefore, often found in hypertensive patients. Patients with hypertension may develop left ventricular hypertrophy, cardiac failure and atherosclerotic vascular problems, such as coronary artery disease, as well as strokes and peripheral vascular disease. There have been a great many advances in our understanding of the pathogenesis of hypertensive heart disease as well as its epidemiology over the last decade and these are reviewed briefly here.

Treatment of atrial fibrillation in a district general hospital

OBJECTIVE

To assess current strategies used to investigate and manage acute atrial fibrillation in hospital.

DESIGN

Prospective survey of all acute admissions over 6 months.

SETTING

District general hospital serving a population of 230,000 in north east Glasgow.

SUBJECTS

2686 patients admitted as emergency cases over 6 months.

RESULTS

Of the 2686 patients, 170 (age range 38-95, mean (SD) 73.5 (10.6) years; 70 men (41%) and 100 women (59%)) were admitted with atrial fibrillation. The principal underlying medical conditions were ischaemic heart disease in 79 (46.5%), rheumatic heart disease in 26 (15.3%), and thyroid disease in six (3.5%). Cardiac failure was present on admission in 61 (36%), cerebrovascular events in 23 (14%), and myocardial infarction in 17 (10%). Of those with a history of atrial fibrillation (102 (60%) including 10 with paroxysmal atrial fibrillation) treatment on admission included digoxin in 71 (70%), warfarin in 20 (20%), and aspirin in 17 (17%); the aspirin was predominantly given for concomitant vascular disease. The mean (SD) inpatient stay was 16 days (19.7) (range 1-154) largely due to the patients with stroke. Thyroid function tests were performed in only 63% and echocardiography in 33%. Overall, the rate of introduction of anticoagulation (seven patients) and attempted cardioversion (21 patient: 19 pharmacological and two electrical) was surprisingly low. Only 49 patients (34% of those not on warfarin) had contraindications to anticoagulation: these included peptic ulcer or gastrointestinal bleeding in 18 (12%), dementia in eight (6%), chronic renal failure or dialysis in eight (6%), and alcohol excess in four (3%).

CONCLUSION

Standard investigations were inadequately used in patients with atrial fibrillation and there was a reluctance to perform cardioversion or to start anticoagulant treatment.

Management of paroxysmal atrial fibrillation

Paroxysmal atrial fibrillation is a common, poorly understood and difficult-to-treat arrhythmia. Although it tends to be treated in a similar fashion to chronic atrial fibrillation, its pathophysiology is different, and drugs commonly used for chronic atrial fibrillation may have only limited value in treating paroxysmal atrial fibrillation. A broad range of presenting clinical symptoms may be associated with this arrhythmia, and even in the asymptomatic patient, there may be a risk of serious thromboembolic events. In symptomatic patients, effective control of paroxysms with antiarrhythmic therapy can often be difficult, and the role of anticoagulation remains controversial. This review attempts to clarify these issues, by surveying the range of therapies available.

An audit of emergency echocardiography in a district general hospital

Eighty patients (43 M, 37 F), aged 23-89 years who were referred for emergency echocardiography over a 12-month period were prospectively studied in order to determine the reasons for emergency echocardiography and the influence of its results on patient management. The most frequent emergency request was to clarify whether the basis for cardiomegaly in a haemodynamically unstable patient was pericardial effusion or left ventricular dilatation. Other reasons for requests were for assessment for source of systemic emboli, acute complications of myocardial infarction, endocarditis, valve dysfunction and cardiac trauma. As a consequence of the emergency echocardiography, management was immediately influenced in 19 patients. This study has provided information on the specific settings in which emergency echocardiography can be justified.

Unilateral pulmonary artery agenesis: a rare cause of haemoptysis and pleuritic chest pain

Haemoptysis and pleuritic chest pain are common presentations of cardiopulmonary disease. While a number of common disorders may explain these symptoms, occasionally unusual causes may emerge which should be considered in the differential diagnosis especially if pulmonary embolism is unlikely; so that inappropriate anticoagulation or thrombolytic therapy is avoided. We present a case of unilateral pulmonary artery agenesis, who presented with pleuritic chest pain and haemoptysis, and was initially treated as a case of pulmonary thromboembolism.

The acute porphyrias

The porphyrias are a heterogeneous group of rare inborn errors of metabolism caused by inherited enzyme defects in the haem biosynthetic pathway, resulting in overproduction of porphyrins. The porphyrias can be distinguished biochemically but may be difficult to differentiate clinically. Considerable advances have been made in the understanding of the enzymology and molecular biology of the porphyrias. The acute attack of porphyria may be a life-threatening condition, and an understanding of its many precipitating factors, clinical features and management is of importance in a disease with a significant mortality.

Sudden death in epilepsy: an avoidable outcome?

In a retrospective survey of mortality among the first 1000 unselected patients referred to the Epilepsy Research Unit at the Western Infirmary in Glasgow between 1985 and 1990, a total of 18 deaths were identified. Three patients had committed suicide and one each had died of status epilepticus in hospital, a subdural haematoma and a myocardial infarction. The remaining 12 deaths (67%) were sudden (median age 32 years; range 22-68 years). Poor seizure control and poor compliance with antiepileptic drug therapy were recorded in only three (25%) of these patients. There was a change in antiepileptic drug regimen in five (28%) in the month before death. Only two (17%) underwent postmortem examination. In nine of the 12 patients dying suddenly, the primary cause of death was not listed as epilepsy but as asphyxia (3), aspiration (2) and one each of ischaemic heart disease, myocardial infarction, asystole and drowning (in the bath). 'Status epilepticus' was assumed to have been responsible for the other three deaths, two of which were unwitnessed. Sudden death in people with epilepsy is an entity of great concern. Appropriate death certification and mandatory postmortem examination are essential to provide a truer picture of this neglected phenomenon.

Adrenaline in allergic emergencies

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