Oxidative stress in malignant and non-malignant phase hypertension

Malignant hypertension (MHT) is a rare and severe form of hypertension characterised by arteriolar necrosis and severe vascular damage, leading to stroke, myocardial infarction and death. We hypothesised that in addition to endothelial damage, MHT may be associated with increased oxidative stress. Lipid hydroperoxides (LHP, an index of oxidative damage) and plasma von Willebrand factor (vWf, an index of endothelial damage/dysfunction) were measured in 16 patients with MHT and compared with 16 non-malignant essential hypertensives and 32 normotensive controls. vWf was greater in MHT (mean 117 iU/dL) than in non-malignant hypertensives (97 iU/dL) or normotensive controls (100 iU/dL) (ANOVA P = 0.017). However, although LHP were greater in MHT (mean 10.6 micromol/L) than in normotensives (4.5 micromol/L, P < 0.001), the levels in MHT were similar to those in non-malignant hypertension (12.3 micromol/L). In conclusion endothelial damage (raised vWf) was more evident in MHT compared with both normotensive controls and with non-malignant hypertension, whilst oxidative stress (raised LHP) was increased to a similar extent in both hypertension groups when compared with normotensive controls. These observations raise the possibility abnormal oxidative stress is probably not the mechanism responsible for the endothelial damage seen in malignant phase hypertension.

Abnormal low-density lipoprotein subfraction profile in patients with untreated hypertension

BACKGROUND

Low-density lipoprotein (LDL) consists of a heterogeneous group of particles of varying size and electrophoretic mobility. A predominance of small, more mobile particles is a risk factor for cardiovascular disease.

AIM

To investigate the hypothesis that untreated patients with essential hypertension in the absence of vascular disease may exhibit abnormalities of LDL subfractions.

SETTING

Specialist hypertension clinic.

DESIGN

Cross-sectional study.

METHODS

Following disc polyacrylamide gel electrophoresis, the mean (LDL locus) and heterogeneity (LDL spread) of mobility was recorded in 41 patients (mean age 52.6 years, 24 men) presenting with untreated essential hypertension (in the absence of vascular disease or diabetes mellitus) and in 45 healthy controls (age 56.9 years, 22 men) recruited from primary-care lists.

RESULTS

Although there were no significant differences in total, low- or high-density lipoprotein cholesterol concentrations, LDL locus was significantly greater in the hypertensive group: mean (95%CI) 36.7 (35.7-37.6) vs. 34.8 (34.1-35.5), p=0.002. LDL locus was significantly elevated even in hypertensives with triglyceride concentrations below the median (<1.25 mmol/l). LDL spread was also greater in the hypertensive group, but not significantly: 5.6 (5.2-6.0) vs. 5.5 (5.3-5.8), p=0.10.

DISCUSSION

Hypertensive patients have a preponderance of smaller LDL subfractions. This dyslipidaemia is not readily detected by conventional lipid assays.

Baseline abnormalities of endothelial function and thrombogenesis in relation to prognosis in essential hypertension

The present study was designed to test the hypothesis that markers of a hypercoagulable state predict subsequent cardiovascular events in hypertensives. To do this, we performed a prospective follow-up analysis of 178 patients (86 male; mean age, 54 years (standard deviation, 15); mean blood pressure, 188/103 mmHg) recruited from a hypertension clinic in a city-centre teaching hospital serving a multi-ethnic population. The main outcome measures were clinical and echocardiographic details, and laboratory markers of thrombosis and haemostasis (fibrinogen, fibrin D-dimer, plasminogen activator inhibitor, soluble P-selectin, von Willebrand factor, and viscosity) that were measured at baseline. After a mean follow-up of 45 months (interquartile range, 37-54), 30 subjects experienced one of a number of endpoints that included death or adverse cardiovascular event. These patients were older (P<0.001) and had significantly higher plasma von Willebrand factor (P=0.015) and fibrin D-dimer levels (P=0.005) compared with those 148 who were free of endpoints at follow-up. There were no statistically significant differences in mean blood pressure, other measured parameters, and the left ventricular mass index between the groups. Using univariate 'time to event' analysis, only high (> or = median) baseline systolic blood pressures were associated with a shortened event-free survival (log rank test, P= 0.0078). We conclude that hypertensive patients who experienced a new cardiovascular event were much older and had more endothelial dysfunction and thrombogenesis than those who were free of complications. However, only high baseline systolic blood pressures were associated with a shortened event-free survival.

Effects of acute exercise on hemorheological, endothelial, and platelet markers in patients with chronic heart failure in sinus rhythm

BACKGROUND

Chronic heart failure (CHF) is associated with an increased risk of thrombosis and thromboembolic events, including stroke and venous thromboembolism. which may be related to a prothrombotic or hypercoagulable state. Acute vigorous exercise has been associated with activation of hemostasis, and this risk may well be particularly increased in patients with CHF.

HYPOTHESIS

The study was undertaken to determine whether acute exercise would adversely affect abnormalities of hemorheological (fibrinogen, plasma viscosity, hematocrit), endothelial (von Willebrand factor), and platelet markers (soluble P selectin) in patients with CHF.

METHODS

We studied 22 ambulant outpatients (17 men; mean age 65+/-9 years) with stable CHF (New York Heart Association class II-III and a left ventricular ejection fraction of < or =40%) who were exercised to exhaustion on a treadmill. Results were compared with 20 hospital controls (patients with vascular disease, but free of CHF) and 20 healthy controls.

RESULTS

Baseline von Willebrand factor (p = 0.01) and soluble P-selectin (p = 0.006) levels were significantly elevated in patients with CHF when compared with controls. In the patients with CHF who were exercised, plasma viscosity, fibrinogen, and hematocrit levels increased significantly, both immediately post exercise and at 20 min into the recovery period (repeated measures analysis of variance, all p<0.05). There was a positive correlation between exercise workload and the maximal changes in plasma viscosity in the patients with CHF (Spearman r = 0.5, p = 0.02). Plasma viscosity levels increased with exercise in the hospital control group, although no other exercise-induced changes were noted in this group.

CONCLUSION

The present study indicates that the hemorheological indices. fibrinogen, and hematocrit specifically increase during acute exercise in patients with CHF. Although moderate exercise should be encouraged in patients with CHF, vigorous exercise should probably be avoided in view of its potential prothrombotic effects in this high-risk group of patients.

A cross-sectional, diurnal, and follow-up study of platelet activation and endothelial dysfunction in malignant phase hypertension

To investigate the hypothesis that abnormalities of thrombogenesis and endothelial damage/dysfunction are greater in malignant hypertension (MHT) compared with uncomplicated nonmalignant essential hypertension (EHT) > 160/90 mm Hg), we measured markers of endothelial function (von Willebrand factor) platelet activation (soluble P-selectin) and fibrinogen in 18 consecutive patients with MHT, 50 patients with untreated EHT, and 34 healthy control subjects. We also investigated whether there was any diurnal variation in the measured indices, as well as the effects of good blood pressure (BP) control after 6-month follow-up. Mean plasma fibrinogen and von Willebrand factor levels were both highest in the MHT group, intermediate in the nonmalignant hypertension group and lowest in the normotensive control subjects (P < .001). Similarly, mean soluble P-selectin levels were higher in both hypertensive groups compared to normotensive control subjects (P = .033). There was no significant diurnal variation in plasma fibrinogen, soluble P-selectin, and von Willebrand factor levels over the 24-h study period among the MHT patients. At 6-month follow-up and a reduction in mean BP, there was no significant change in mean plasma fibrinogen levels (P = .25), but both soluble P-selectin (P < .001) and von Willebrand factor (P = .0025) were significantly reduced. In conclusion, malignant hypertension is associated with abnormal endothelial damage (elevated von Willebrand factor), platelet activation (soluble P-selectin), and fibrinogen levels, which may be related to the pathogenesis of this condition, as well as the development of complications. These abnormalities do not undergo any significant diurnal variation and may be beneficially altered by BP reduction.

A pilot study of homocyst(e)ine levels in essential hypertension: relationship to von Willebrand factor, an index of endothelial damage

An interaction between homocyst(e)ine and the endothelium in hypertensive patients may promote thrombogenesis and atherogenesis, leading to adverse cardiovascular events. We hypothesized that homocyst(e)ine levels are abnormal in patients with essential hypertension, and that this may be related to an adverse effect on the vascular endothelium. Accordingly, we compared plasma levels of homocyst(e)ine and von Willebrand factor (marking endothelial damage) in 83 patients (43 men; mean age 54 +/- standard deviation 15.9 years) with essential hypertension (> 160/90 mm Hg), with levels in 25 healthy normotensive controls (13 men; mean age 56+/-11.8 years). Baseline levels of the markers and other clinical indices were then related to adverse cardiovascular events at follow-up. Plasma homocyst(e)ine (P = .0001) and von Willebrand factor (P = .031) levels were significantly higher in hypertensives compared to controls. After a mean follow-up of 76 patients for 45 months (range, 1 to 66 months), 17 subjects experienced an end point of either cardiovascular death (n = 10) or adverse cardiovascular event (n = 7). Comparing these 17 with the 59 free of an end point, the former were older (P = .0002) and had a longer duration of known hypertension (P = .018). There was a nonsignificant trend toward higher median plasma homocyst(e)ine levels in the patients sustaining a vascular end point (P = .07). In this pilot study, we suggest that essential hypertension may be associated with increased plasma homocyst(e)ine levels, but that this amino acid is unrelated to endothelial damage (von Willebrand factor), clinical indices, or prognosis.

Dyslipidaemia in patients with malignant-phase hypertension

Low-density lipoprotein (LDL) consists of a heterogeneous group of particles of differing size, density and electrophoretic mobility, smaller particles being more atherogenic. A high proportion of small LDL particles is an independent risk factor for cardiovascular disease. We hypothesized that patients with malignant phase hypertension (MHT), the most severe form of hypertension, would demonstrate a more atherogenic LDL subfraction profile than either non-malignant hypertension (NMHT) or normotensive controls. We compared 16 patients with MHT to 41 patients with untreated NMHT and 45 normotensive controls. LDL subfraction profile was measured by disc polyacrylamide gel electrophoresis using a validated scoring system to calculate the mean size (locus) and heterogeneity (spread) of LDL subfraction mobilities. A higher LDL locus indicates a greater proportion of small LDL subfractions. LDL cholesterol levels were similar in all three groups (p=0.23). High-density lipoprotein cholesterol (HDL-C) levels were significantly lower (p<0.001) and serum triglyceride concentrations significantly higher (p=0.02) in the MHT group, compared to normotensive controls. LDL locus was greater in the NMHT group than in the normotensive controls and intermediate in the MHT group (p=0.008). There was no significant difference in LDL spread (p=0.26). Serum triglyceride concentrations were not significantly higher after adjusting for confounding variables. MHT is associated with an abnormal lipid profile, characterized by low HDL-cholesterol concentration. This dyslipidaemia may be partly responsible for the vascular complications and the poor prognosis of these patients.

Effect of acute exercise on the raised plasma fibrinogen, soluble P-selectin and von Willebrand factor levels in chronic atrial fibrillation

BACKGROUND

There is increasing evidence that chronic atrial fibrillation (AF) is associated with a prothrombotic or hypercoagulable state.

HYPOTHESIS

This study was undertaken to determine whether short-term exercise in patients with chronic AF would shift the overall hemostatic balance toward a more prothrombotic state with a reduction in fibrinolytic potential.

METHODS

We recruited 20 patients (13 men; mean age 65 years +/- 11 standard deviation [SD]) with chronic AF who were not treated with antithrombotic therapy and exercised them to exhaustion using a multistage treadmill exercise (standard Bruce) protocol. Blood samples were taken pre exercise, immediately after cessation of exercise, and at 20 min post exercise. The prothrombotic state was quantified by fibrinogen (an index of hemorheology and a coagulation factor), soluble P-selectin (sP-sel, marking platelet activation), von Willebrand factor (vWF, an index of endothelial dysfunction), and plasminogen activator inhibitor-1 (PAI-1, a regulator of fibrinolytic activity) levels. There were two groups of age- and gender-matched controls in sinus rhythm: (1) healthy controls, and (2) "hospital controls" who were patients with vascular disease.

RESULTS

Baseline levels of vWf (p = 0.034) and fibrinogen (p < 0.0001), but not sP-sel (p = 0.075) were significantly elevated in patients with AF compared with both control groups in sinus rhythm. The PAI-1 levels were highest in the hospital control patients, but not in chronic AF (p = 0.041). Following treadmill exercise, achieving a mean metabolic equivalent of 4.9 METS (+/- 1.75 SD) and total exercise duration of 4.9 min (+/- 2 SD), there was a significant rise in plasma fibrinogen (repeated measures analysis of variance [ANOVA] p = 0.047) and a reduction in PAI-1 levels (p = 0.025) in patients with AF. There were no significant changes seen in vWf (p = 0.308) or sP-sel (p = 0.071) levels. No significant changes in these indices were seen in hospital controls (all p = not significant), despite a much longer duration of exercise with greater workload.

CONCLUSION

Patients with chronic AF have increased vWf and fibrinogen levels compared with sinus rhythm. Exercise to exhaustion influences the hypercoagulable state in chronic AF, with a rise in plasma fibrinogen and possible increase in fibrinolytic activity. Nevertheless, acute exercise does not appear to have a significant influence on endothelial dysfunction or platelet activation in patients with AF.

Should patients with hypertension receive antithrombotic therapy?

The main complications of hypertension, i.e. coronary heart disease, ischaemic strokes and peripheral vascular disease (PVD), are usually related to thrombosis. Increasing evidence also suggests that hypertension fulfils the components of Virchow's triad, thus conferring a prothrombotic or hypercoagulable state, as evident by abnormalities of haemostasis, platelets and endothelial function. It therefore seems plausible that use of antithrombotic therapy may help prevent these thrombosis-related complications of hypertension. Indeed, hypertensive patients with an estimated 10-year CHD risk > or = 15% will have their cardiovascular risk reduced by 25% using antihypertensive treatment, but the addition of aspirin further reduces major cardiovascular events by 15%. Recent guidelines recommend the use of aspirin 75 mg daily for hypertensive patients who have no contraindication to aspirin, in one of the following categories: (i) secondary prevention - cardiovascular complications (myocardial infarction, angina, non-haemorrhagic stroke, peripheral vascular disease or atherosclerotic renovascular disease); and (ii) primary prevention - those with blood pressure controlled to < 150/90 mmHg and one of: (a) age > or = 50 years and target organ damage (e.g. LVH, renal impairment, or proteinuria); (b) a 10-year CHD risk > or = 15%; or (c) type II diabetes mellitus. However, some of the risks of aspirin administration, namely increased incidence of major bleeding events, may possibly outweigh the benefits, especially in low-risk individuals.

Matrix metalloproteinase-9 and tissue inhibitor metalloproteinase-1 levels in essential hypertension. Relationship to left ventricular mass and anti-hypertensive therapy

To test the hypothesis that the activity of enzymes degrading the extracellular matrix in hypertensive patients are abnormal, and that the treatment of hypertension will normalise these abnormalities, we measured the serum levels of metalloproteinase MMP-9, and its inhibitor, tissue metalloproteinase inhibitor (TIMP-1). Thirty-two patients with untreated hypertension (BP 168/96) had significantly lower levels of both MMP-9 and TIMP-1 when compared to 24 matched normotensive controls (BP 123/80) (P<0.001). There was no significant correlation between MMP-9 and TIMP-1 levels (P>0.2). In the patients, there were no significant correlations observed between left ventricular mass, Doppler V(E)/V(A) ratio (an index of diastolic function), blood pressure, left ventricular mass index and either MMP-9 or TIMP-1 levels (all P=NS). Levels of MMP-9 and TIMP-1 were not significantly altered after 2 months of antihypertensive treatment of 29 patients despite mean blood pressure falling from 170/96 to 143/85 mmHg (P<0.001). Correspondingly, there were also no significant alterations in indices of diastolic function and left ventricular mass. Our study suggests that the proteolytic activities of MMP-9 and TIMP-l are depressed in hypertensive patients and were not significantly affected by short-term antihypertensive treatment. The relationship between collagen metabolism in hypertensive subjects, especially in those with cardiac hypertrophy, and the effects of treatment needs to be further explored in larger trials over a longer period of time.

Setting up a heart emergency centre

We describe the setting up of a 'heart emergency centre' linked to a pre-existing coronary care unit. The 'heart emergency centre' offers a new and efficient way of providing a fast and effective system for the assessment and management of patients with cardiac emergencies. This set-up can result in significant improvements in 'door to needle' time for thrombolysis, which has been shown to be beneficial both in terms of morbidity and mortality following myocardial infarction.

A longitudinal psychopathological schedule

A schedule is described for rating the symptoms of mental illness over a period of time which includes several episodes. The reliability was measured in a study involving six raters. The sources of information required were studied, in 20 patients, by comparing an interview with the patient, a similar interview with an informant and an analysis of the case records. A synopsis of interview and record data are necessary to obtain adequate information about longitudinal psychopathology and 'lifetime' diagnosis.

Hypomania following complex partial seizures. A report of three cases

Depressive disorders are commonly found among selected groups of patients with epilepsy, but hypomania is seldom seen. Three cases of hypomania seen at a unit specialising in epilepsy are presented. The cases are of interest because of their association with recent seizures, and location in the non-dominant temporal lobe.