Response of Femoral Venous Oxygen Tension to Graduated Pressure Stockings - Possible Relationship to Deep Vein Thrombosis

Venous oxygen tension (pO2) was measured in discrete samples of blood obtained through the femoral vein of cardiac catheterisation patients before, during and after application of sustained external graduated pressure in the form of compression stockings (T. E. D. Kendall). There was a significant reduction (p <0.05) of pO2 from the baseline value both 30 sec and one minute after the application of the pressure stockings. Thereafter, the pO2 rose to baseline values. Two minutes after the stockings were removed there was again a significant reduction (p <0.05) of pO2 from the baseline value. We suggest that the decrease in ivenous pO2 on application of external pressure may be a reflection of washing out of stagnant hypoxic blood from the venous valve pockets, which may be related to the formation of deep vein thrombosis (DVT).

Pravastatin and the development of diabetes mellitus: evidence for a protective treatment effect in the West of Scotland Coronary Prevention Study

BACKGROUND

We examined the development of new diabetes mellitus in men aged 45 to 64 years during the West of Scotland Coronary Prevention Study.

METHODS AND RESULTS

Our definition of diabetes mellitus was based on the American Diabetic Association threshold of a blood glucose level of >/=7.0 mmol/L. Subjects who self-reported diabetes at baseline or had a baseline glucose level of >/=7.0 mmol/L were excluded from the analyses. A total of 5974 of the 6595 randomized subjects were included in the analysis, and 139 subjects became diabetic during the study. The baseline predictors of the transition from normal glucose control to diabetes were studied. In the univariate model, body mass index, log triglyceride, log white blood cell count, systolic blood pressure, total and HDL cholesterol, glucose, and randomized treatment assignment to pravastatin were significant predictors. In a multivariate model, body mass index, log triglyceride, glucose, and pravastatin therapy were retained as predictors of diabetes in this cohort.

CONCLUSIONS

We concluded that the assignment to pravastatin therapy resulted in a 30% reduction (P:=0.042) in the hazard of becoming diabetic. By lowering plasma triglyceride levels, pravastatin therapy may favorably influence the development of diabetes, but other explanations, such as the anti-inflammatory properties of this drug in combination with its endothelial effects, cannot be excluded with these analyses.

Auditing the implementation of SIGN (Scottish Intercollegiate Guidelines Network) clinical guidelines

Clinical practice guidelines are increasingly being recognised as integral to the clinical effectiveness agenda. According to the recent Scottish White Paper, Scotland "leads the way in clinical effectiveness". The Scottish Intercollegiate Guidelines Network (SIGN), established in 1993, has produced over 20 clinical practice guidelines, and plans to produce at least as many more, while reviewing existing guidelines at a minimum of every two years. This represents a substantial investment of NHS resources. This paper investigates whether this investment is being recouped in Scottish NHS acute trusts via the implementation of SIGN guidelines, and whether their implementation is being audited properly. It is argued that without clinical audit, guideline implementation is unlikely to succeed. This has important ramifications for the implementation of clinical governance.

Health and efficiency: clinical effectiveness dissected

If the exclusive promotion of values inimical to our basic humanity extends to the health care policy arena, we face a defensive, restricted, impersonal and ultimately impoverished health care system. Americans known it already as 'managed-care'. This is why it is crucial for health policy analysts to make explicit the role of values in policy-making, especially that involving the input of 'value-neutral' economics. The nature of any clinical effectiveness policy will be determined by the understanding of cost-effectiveness employed in its design and implementation. Given that cost-effectiveness is nowadays usually defined according to health economists' criteria, the battle over the meaning of clinical effectiveness is a significant development in health economics' move to assume control of the NHS.

Differences between amlodipine and lisinopril in control of clinic and twenty-four hour ambulatory blood pressures

The anti-hypertensive efficacy of once-daily amlodipine (up to 10 mg) and lisinopril (up to 20 mg) were compared in terms of clinic and ambulatory blood pressure (BP) control, in an observer-blind, two-period crossover study. Following a 4-week placebo run-in period, patients underwent two active treatment phases each lasting 12 weeks and separated by a 4-week washout period. Sixty patients with a supine diastolic BP between 90 and 120 mm Hg were included, irrespective of whether or not they had received previous anti-hypertensive medication. Amlodipine reduced supine systolic and diastolic clinic BP significantly more than lisinopril (-20+/-2/-14+/-1 vs -11 3/-7+/-1 mm Hg; P=0.02/ P=0.001) 24 h post-dose. Clinic standing diastolic BP was also significantly reduced with amlodipine compared with lisinopril (P=0.05). Both drugs produced control of mean ambulatory BP relative to baseline over 24 h. Amlodipine showed more consistent control of BP over the 24-h period in contrast to lisinopril which exerted its greatest effect during the daytime.

Effects of colestipol alone and in combination with simvastatin on apolipoprotein B metabolism

The effects of colestipol therapy alone (20 g/d) or combined with simvastatin (20 mg/d) were examined in a group of eight male patients with primary moderate hypercholesterolemia (total cholesterol > or = 6.5 mmol/L [> or = 250 mg/dL]) who had undergone coronary artery bypass grafting more than 3 months previously. Colestipol therapy decreased total cholesterol by 14% (P < .001) and LDL cholesterol (LDL-C) by 23% (P < .001), while dual therapy decreased total cholesterol by 38% and LDL-C by 52% (both P < .001 versus baseline). No significant changes were observed in plasma triglyceride, VLDL cholesterol, or HDL cholesterol levels. VLDL subfraction turnovers were conducted at baseline and again on each regimen. ApoB kinetic parameters derived from a multicompartmental model suggested that colestipol therapy resulted in an expansion of the total VLDL apoB pool (36%, P < .05) that was largely due to a fall in the clearance rate of VLDL1 apoB (49%), while the LDL apoB pool decreased 23% as a result of diminished direct LDL input. The model used also revealed that addition of simvastatin to the resin therapy caused increases in the fractional transfer rates of VLDL2 to IDL and IDL to LDL together with a 37% increment in the LDL apoB fractional catabolic rate. Compared with baseline, combined therapy generated falls in both IDL (35%, P = .01) and LDL (37%, P < .04) apoB pools due to enhanced clearance of IDL (214%, P < .03) and reduced total input of LDL (39%, P < .003).

Prevention of coronary heart disease with pravastatin in men with hypercholesterolemia. West of Scotland Coronary Prevention Study Group

BACKGROUND

Lowering the blood cholesterol level may reduce the risk of coronary heart disease. This double-blind study was designed to determine whether the administration of pravastatin to men with hypercholesterolemia and no history of myocardial infarction reduced the combined incidence of nonfatal myocardial infarction and death from coronary heart disease.

METHODS

We randomly assigned 6595 men, 45 to 64 years of age, with a mean (+/- SD) plasma cholesterol level of 272 +/- 23 mg per deciliter (7.0 +/- 0.6 mmol per liter) to receive pravastatin (40 mg each evening) or placebo. The average follow-up period was 4.9 years. Medical records, electrocardiographic recordings, and the national death registry were used to determine the clinical end points.

RESULTS

Pravastatin lowered plasma cholesterol levels by 20 percent and low-density-lipoprotein cholesterol levels by 26 percent, whereas there was no change with placebo. There were 248 definite coronary events (specified as nonfatal myocardial infarction or death from coronary heart disease) in the placebo group, and 174 in the pravastatin group (relative reduction in risk with pravastatin, 31 percent; 95 percent confidence interval, 17 to 43 percent; P < 0.001). There were similar reductions in the risk of definite nonfatal myocardial infarctions (31 percent reduction, P < 0.001), death from coronary heart disease (definite cases alone: 28 percent reduction, P = 0.13; definite plus suspected cases: 33 percent reduction, P = 0.042), and death from all cardiovascular causes (32 percent reduction, P = 0.033). There was no excess of deaths from noncardiovascular causes in the pravastatin group. We observed a 22 percent reduction in the risk of death from any cause in the pravastatin group (95 percent confidence interval, 0 to 40 percent; P = 0.051).

CONCLUSIONS

Treatment with pravastatin significantly reduced the incidence of myocardial infarction and death from cardiovascular causes without adversely affecting the risk of death from noncardiovascular causes in men with moderate hypercholesterolemia and no history of myocardial infarction.

Metabolism of apolipoprotein B in primary moderate hypercholesterolaemia: effects of acipimox and cholestyramine therapy

The effects of combined therapy with acipimox (1250 mg/day) and cholestyramine (20 g/day) were examined in a group of 7 subjects with primary moderate hypercholesterolaemia (total cholesterol >=7 mmol/L). Radiolabeled VLDL subfraction turnovers were performed at baseline, during acipimox therapy and during combined therapy. Acipimox and combined therapies lowered plasma low density lipoprotein (LDL)-cholesterol by 20% (P<0.001) and 27% (P<0.001) respectively. The marked fall in LDL-cholesterol associated with acipimox therapy, was due to a reduced production rate of LDL (apolipoprotein) apoB. This is shown to be a result of reduced direct LDL apoB production, reduced IDL to LDL transfer consistent with inhibition of hepatic triglyceride lipase, and with a reduction in the overall throughput of VLDL1 apoB. With combined therapy both reduced production and increased catabolism of apoB containing LDL precursors and of LDL itself have to be invoked to explain the fall in plasma LDL-cholesterol.

Heart rate variability in left ventricular hypertrophy

BACKGROUND

Electrocardiographic left ventricular hypertrophy and strain are associated with increased cardiac morbidity and mortality. Impaired cardiac autonomic function, assessed non-invasively by spontaneous heart rate variability on Holter monitoring, is associated with an increased risk of sudden death after myocardial infarction.

AIM

To study the effect of left ventricular hypertrophy on heart rate variability.

PATIENTS

36 controls and 154 patients with left ventricular hypertrophy (94 with hypertension and 60 with aortic valve disease).

SETTING

Tertiary referral centre.

METHODS

Heart rate variability was measured on 24 h Holter recordings by non-spectral methods. Left ventricular mass index and fractional shortening were measured by echocardiography.

RESULTS

Patients with left ventricular hypertrophy had a higher left ventricular mass index (P < 0.001) and reduced heart rate variability (P < 0.001) compared with those of the controls. A continuous inverse relation was apparent between heart rate variability and left ventricular mass index (r = -0.478, P < 0.001). Heart rate variability was not affected by age, the presence of coronary artery disease in patients with left ventricular hypertrophy, or beta blocker treatment for hypertension. Multivariate analysis showed that left ventricular mass index is the most important determinant of heart rate variability.

CONCLUSION

Heart rate variability is significantly reduced in patients with left ventricular hypertrophy secondary to hypertension or aortic valve disease. A continuous inverse relation exists between heart rate variability and left ventricular mass index. Impaired cardiac autonomic function in left ventricular hypertrophy may contribute to the mechanism of sudden death.

Overproduction of small very low density lipoproteins (Sf 20-60) in moderate hypercholesterolemia: relationships between apolipoprotein B kinetics and plasma lipoproteins

An analysis of apolipoprotein (apo) B turnovers conducted in subjects with moderate hypercholesterolemia was performed to discover relationships that may exist between apoB kinetic parameters and plasma lipid and lipoprotein levels. A group of 21 subjects with plasma cholesterol in the range 250-300 mg/dl and triglyceride < 265 mg/dl were injected with tracers of 131I-labeled very low density lipoprotein 1 (VLDL1, Sf 60-400) and 125I-labeled VLDL2 (Sf 20-60) prepared by cumulative flotation ultracentrifugation. The metabolism of apoB in these fractions was followed through intermediate density (IDL, Sf 12-20) to low density (LDL, Sf 0-12) lipoprotein. The most consistent feature giving rise to the higher apoB levels that occurred in VLDL2, IDL, and LDL in the hypercholesterolemic group was increased input of VLDL2 (787 +/- 607 (SD) mg/day vs. 349 +/- 213 in normals, P < 0.01). VLDL1 apoB input was variably affected and not significantly different from normal. However, the plasma residence time of this subfraction was increased (0.15 +/- 0.07 days vs. 0.08 +/- 0.03 days in normals, (P < 0.001) due to a decreased fractional rate of direct catabolism. Fractional transfer rates (FTR) down the delipidation cascade and other fractional rates of direct catabolism were, overall, not significantly different from normal. The plasma residence time of VLDL2 apoB and LDL apoB was similar in hypercholesterolemic and normal subjects, while that of IDL apoB was slightly increased. Variation in LDL apoB mass within the hypercholesterolemic group correlated with VLDL1 apoB input (r = 0.58, P = 0.006), the fractional rate of transfer from IDL to LDL (r = 0.61, P = 0.003), and direct LDL input (r = 0.64, P = 0.002). The proportion of LDL apoB mass derived by direct, i.e., VLDL-independent input, varied from 5 to 50% and was inversely correlated with plasma triglyceride (r = -0.53, P = 0.014) and positively with HDL2 (r = 0.66, P = 0.002). In addition, the amount of direct LDL input was related to the amount of VLDL1 removed by direct catabolism (r = 0.53, P = 0.013). The analysis indicated that moderate hypercholesterolemia arose principally from overproduction of small VLDL, while variation in VLDL1 input and the IDL to LDL conversion rate (presumably hepatic lipase-mediated) modulated the extent of the elevation in LDL apoB.

Association between myotonic dystrophy and primary hyperparathyroidism

A case of primary hyperparathyroidism in a patient with myotonic dystrophy is reported. A 56-year old female with myotonic dystrophy, admitted to hospital with a urinary tract infection, had widespread muscle atrophy and myotonia with bilateral cataracts. Biochemical findings of normal renal function but raised blood calcium, depressed blood phosphate and increased parathyroid hormone, were consistent with a diagnosis of primary hyperparathyroidism. Thallium scanning of the parathyroids showed an area of discordant thallium suggesting a parathyroid adenoma. When the left lower parathyroid was later excised, histology was consistent with the diagnosis of parathyroid adenoma. As far as the authors are aware this is the first report of myotonic dystrophy and primary hyperparathyroidism in the same patient.

The role of nuclear cardiology in hypertension

In view of the increased risk of cardiac events in systemic hypertension, particularly in patients with left ventricular hypertrophy, it is important to have reliable methods of assessing cardiac structure and function and myocardial perfusion in these patients. While echocardiography is the noninvasive method of choice for measuring the severity of left ventricular hypertrophy there is no alternative at present to invasive coronary angiography to define accurately coronary artery anatomy. Nuclear cardiological investigations are extremely useful in the assessment of systolic and diastolic function at rest and during exercise. Furthermore, myocardial perfusion imaging is of value in identifying myocardial ischaemia and assessing the functional importance of coronary artery lesions. Recent studies have also suggested that nuclear cardiology investigations may be the best way to identify nonfunctioning but viable areas of the myocardium which may benefit from revascularization.

Double-blind comparison of amlodipine and nifedipine retard in the treatment of mild to moderate hypertension

The efficacy and safety profiles of amlodipine (5-10 mg once daily) and nifedipine retard (20-40 mg twice daily) were compared in 111 hypertensive patients (sitting DBP in 95-115 mmHg) during eight weeks of treatment in a randomised double-blind parallel group study. BP was measured 22-24 hours after the daily dose of amlodipine and 10-12 hours after a dose of nifedipine retard. Baseline sitting BPs of 175/105 mmHg and 168/104 mmHg were significantly reduced (P < 0.05) to 157/93 mmHg and 151/92 mmHg at the end of treatment in response to mean daily doses of amlodipine 7.3 mg and nifedipine retard 58.9 mg. There were no clinically significant changes in heart rate with either treatment. Three patients in the amlodipine group and five patients in the nifedipine retard group could not be considered in analysis. The total numbers of adverse events (considered related or possibly related to treatment) (42 vs. 36) as well as the numbers of patients experiencing such events (22 vs. 22) were similar in the amlodipine and nifedipine retard treated groups, respectively, but with a greater incidence of headaches in response to nifedipine retard and of oedema in response to amlodipine. Five patients in each treatment group discontinued therapy due to such events. Overall the results showed once daily amlodipine as equivalent to twice daily nifedipine retard in the management of mild to moderate hypertension.

Effects of atenolol withdrawal in patients on triple antihypertensive therapy

The objective of this study was to examine the contribution of beta-blockade to antihypertensive treatment regimens including an angiotensin converting enzyme inhibitor or a calcium antagonist. The effects on BP control, adverse events, and plasma active renin concentration of removing atenolol from standard triple therapy (bendrofluazide and atenolol together with captopril or nifedipine) were assessed in a double-blind, randomised, parallel-group study, of eight weeks' duration in 46 patients from the Glasgow Blood Pressure Clinic. Blood pressures rose in patients randomised to placebo-atenolol compared with those who continued active-atenolol although the difference did not achieve statistical significance. However, the proportion of patients with controlled blood pressure (supine systolic BP < 140 mmHg plus supine diastolic BP < 95 mmHg) fell from 31% to 0% over the study period in patients given placebo-atenolol. There was a trend for BP control to deteriorate most when atenolol was withdrawn from nifedipine treated patients, but the 95% confidence intervals for the difference from captopril-treated patients were wide. Few side-effects were seen and these did not differ quantitatively between the study groups. Plasma active renin concentration was initially higher in captopril-treated patients, and increased on withdrawal of atenolol in both groups. Our findings suggest that beta-blockers make a clinically relevant contribution to treatment regimens including angiotensin converting enzyme inhibitors or calcium antagonists when given as part of standard triple antihypertensive therapy.

Effects of simvastatin on apoB metabolism and LDL subfraction distribution

Seven moderately hypercholesterolemic subjects were studied before and after 10 weeks of simvastatin therapy (20 mg/day). Therapy reduced low density lipoprotein (LDL) cholesterol by 39% (p < 0.001), whereas high density lipoprotein and very low density lipoprotein (VLDL) cholesterol were unchanged. Apolipoprotein (apo) B-containing lipoproteins were divided into VLDL1 (Sf 60-400), VLDL2 (Sf 20-60), intermediate density lipoprotein (IDL) (Sf 12-20), and LDL (Sf 0-12), and metabolic changes were sought in dual-tracer VLDL1 and VLDL2 turnover studies. VLDL1 apoB pool size was unaltered by therapy, as were its rates of synthesis, catabolism, and delipidation to VLDL2. Similarly, the VLDL2 apoB pool size was unchanged, but its metabolic fate was altered. The IDL pool size fell significantly (27%, p < 0.01) due entirely to an increased fractional catabolism of the lipoprotein. In our subjects, the circulating mass of LDL apoB decreased (49%, p < 0.01) primarily due to a reduction in its synthesis. Before therapy, 30% of the apoB entering the delipidation cascade in these hyperlipidemic subjects was converted to LDL. On therapy the input remained the same, but direct catabolism from VLDL2 and IDL was increased (p < 0.05), and as a result only 16% eventually appeared in LDL. These kinetic changes were associated with a fall in particle cholesteryl ester content throughout the delipidation cascade. We also observed a link between LDL kinetics and its subfraction distribution. Simvastatin influences the metabolism of LDL, IDL, and VLDL2 but not VLDL1.

Comparison of captopril, hydralazine and nifedipine as third drug in hypertensive patients

The antihypertensive, biochemical and adverse effects of captopril, hydralazine, nifedipine and placebo were compared in 160 patients with BP inadequately controlled by atenolol 100 mg daily plus bendrofluazide 5 mg daily. Treatments were given for up to 12 weeks. Beta-blocker and thiazide were continued unchanged. All three active drugs reduced supine BP relative to placebo; mean BP changes attributable to active treatment (95% confidence intervals): captopril 13.4/10.3 mmHg (0.6/4.0 to 26.2/16.6), hydralazine 15.0/10.0 mmHg (1.7/3.4 to 28.3/16.6), nifedipine 16.8/8.1 mmHg (4.0/1.8 to 29.6/14.4). There were no significant differences between the agents. Results for erect BP were similar. Target BP (< 140/95 mmHg) was achieved more frequently on captopril (33%), hydralazine (29%) and nifedipine (17%) than on placebo (10%). Compared with the other treatments captopril increased serum potassium concentration (P = 0.01), and hydralazine reduced serum cholesterol concentration (median changes: captopril -0.2 mmol/l, hydralazine -0.8 mmol/l, nifedipine -0.2 mmol/l, and placebo +0.2 mmol/l, P < 0.001). Overall, side-effects did not differ significantly between the groups; withdrawals resulting from adverse reactions: captopril 15%, hydralazine 24%, nifedipine 22%, and placebo 3% (chi 2 = 8.2, P = 0.04). Captopril, hydralazine and nifedipine did not differ significantly in efficacy and tolerability when added to atenolol and bendrofluazide. However, there were trends in favour of captopril, on which drug the highest proportion of patients had their BP controlled and the lowest proportion were withdrawn because of side-effects. Thus, of the drugs tested, captopril appears to be the best option as third drug in hypertension.

Probucol reduces plasma lipid peroxides in man

Although primarily used as a lipid lowering drug, probucol also possesses anti-oxidant activity and has been shown in animal models to inhibit or delay the progression of atherosclerosis. It has been suggested that this anti-atherosclerotic effect may occur through inhibition of free radical oxidation of low density lipoprotein. The aim of this study was to investigate the effects of probucol on free radical activity in hyperlipidaemic patients. Plasma lipid peroxides were measured before probucol treatment, at 4 and 12 weeks treatment and then 4 weeks after stopping probucol. Lipid peroxide concentrations were significantly reduced during and 4 weeks after stopping treatment with probucol, when compared with baseline values. There were no changes in plasma vitamin E concentrations. The results of this study indicate that probucol reduces lipid peroxidation in patients, an effect which may occur through a free radical scavenging action.

Candoxatril, a neutral endopeptidase inhibitor: efficacy and tolerability in essential hypertension

OBJECTIVE

To examine the efficacy and tolerability of the neutral endopeptidase inhibitor, candoxatril (UK 79,300) as monotherapy in essential hypertension.

DESIGN

Double-blind, placebo-controlled, parallel-group study of 28 days' duration.

SETTING

Three hospital outpatient departments participating in the Glasgow Blood Pressure Clinic (Glasgow, UK).

PATIENTS

Forty patients with essential hypertension with diastolic blood pressure 95-114 mmHg after a 2-4 week placebo run-in period.

INTERVENTIONS

Twenty-eight days' treatment with candoxatril 200 mg twice daily or matching placebo capsules.

MAIN OUTCOME MEASURES

Changes in supine and erect blood pressure, and volunteered side effects during double-blind treatment.

RESULTS

When measured at the end of the dose interval, the fall in supine blood pressure following candoxatril was not significantly greater than that after placebo. Compared with placebo, a significant effect for candoxatril was seen only for systolic blood pressure in the erect posture; the fall in erect diastolic blood pressure attributable to candoxatril was insignificant. Median plasma atrial natriuretic peptide concentration increased in candoxatril-treated patients and decreased in the placebo group. No stimulation of the renin-aldosterone axis was seen. There was a non-significant trend towards greater urinary excretion of cyclic guanosine monophosphate after candoxatril. Mean plasma concentration of candoxatril at (UK 73,967--the active metabolite of candoxatril) reached a peak of 1010 +/- 437 ng/ml after acute dosing, and 1328 +/- 405 ng/ml after chronic dosing; time to maximum concentration was 2 h in each case. Candoxatril was well-tolerated; numbers of adverse events did not differ between active treatment and placebo.

CONCLUSIONS

Although atrial natriuretic peptide levels were significantly increased, candoxatril 200 mg twice daily for 28 days did not produce a clinically relevant fall in blood pressure. Our results cast some doubt upon the role of neutral endopeptidase inhibition in the treatment of unselected hypertensive patients.

Symptomatic and silent myocardial ischaemia in hypertensive patients with left ventricular hypertrophy

OBJECTIVE

To assess the prevalence of symptomatic and silent myocardial ischaemia in patients with hypertensive left ventricular hypertrophy.

DESIGN

Cross sectional study.

SETTING

University department of medical cardiology.

PATIENTS

90 patients (68 men and 22 women; mean age 57 (range 25 to 79)) with left ventricular hypertrophy due to essential hypertension.

INTERVENTIONS

48 hour ambulatory ST segment monitoring (all patients), exercise electrocardiography (n = 79), stress thallium scintigraphy (n = 80), coronary arteriography (n = 35).

RESULTS

43 patients had at least one episode of ST segment depression on ambulatory electrocardiographic monitoring. The median number of episodes was 16 (range 1 to 84) with a median duration of 8.6 (range 2 to 17) min. Over 90% of these episodes were clinically silent. 26 patients had positive exercise electrocardiography and 48 patients had reversible thallium perfusion defects despite chest pain during exercise in only five patients. 18 of the 35 patients who had coronary arteriography had important coronary artery disease. Seven of these patients gave no history of chest pain.

CONCLUSIONS

Symptomatic and silent myocardial ischaemia are common in hypertensive patients with left ventricular hypertrophy, even in the absence of epicardial coronary artery disease.

Significance of ventricular arrhythmias in systemic hypertension with left ventricular hypertrophy

Hypertensive patients with the electrocardiographic (ECG) pattern of left ventricular (LV) hypertrophy and strain are at increased risk of sudden death. It has been suggested that ventricular arrhythmias may be responsible. The prevalence and significance of ventricular arrhythmias was therefore studied in 90 hypertensive patients with LV hypertrophy and strain by undertaking 48-hour ambulatory ECG monitoring, ECG signal-averaging and programmed ventricular stimulation. Complex ventricular ectopic activity (Lown grade greater than or equal to 3) was detected in 59 patients (66%). Eleven patients (12%) had episodes of nonsustained ventricular tachycardia. There were no sustained arrhythmias either on ambulatory ECG monitoring or induced by programmed ventricular stimulation. Only 1 patient had ventricular late potentials recorded by the signal-averaged electrocardiogram. Therefore, there was little to suggest an underlying arrhythmogenic substrate in these patients. In conclusion, whereas ventricular arrhythmias occur often in patients with LV hypertrophy associated with systemic hypertension, their significance, if any, remains to be established.

Felodipine extended release in mild to moderate hypertension

A multi-centre study was carried out to examine the antihypertensive effect and adverse event profile of felodipine in an extended-release (ER) formulation given once daily as monotherapy. Doses of 5 mg, 10 mg or 20 mg felodipine ER were compared with placebo in 183 patients with mild or moderate hypertension. All antihypertensive medication was discontinued on entering a 4-week placebo run-in period. If, at the end of the run-in period, supine diastolic blood pressure was in the range greater than 95 less than 120 mmHg, patients were randomly allocated to double-blind treatment with felodipine, 5 mg, 10 mg or 20 mg, or placebo, to be taken once daily for 4 weeks. Supine and standing blood pressure, heart rate and body weight were measured every 2 weeks during the trial. Assessments were made 24 hours after intake of the study drug. Adverse events were recorded at each review. Over the 4-week treatment period, a dose-related decrease in supine diastolic blood pressure was observed, this reduction occurring already during the first 2 weeks of active treatment. In the placebo group and the felodipine 5 mg, 10 mg and 20 mg groups, supine blood pressure (systolic/diastolic) decreased by 7/6 mmHg, 9/8 mmHg, 12/10 mmHg and 14/11 mmHg, respectively. Supine diastolic blood pressure reduction in the felodipine 10 mg group and both systolic and diastolic blood pressure reductions in the 20 mg group were significantly greater than with placebo. Standing diastolic blood pressure reduction was significantly greater in all three dose groups on felodipine compared with placebo.(ABSTRACT TRUNCATED AT 250 WORDS)

Postprandial lipemia, fenofibrate and coronary artery disease

This report describes the response of patients with severe coronary artery disease to a dynamic fat load test and monitors the change induced by fenofibrate therapy. The presence of disease was associated with prolonged and exaggerated hypertriglyceridemia following the meal and with lower basal HDL cholesterol and HDL subfraction masses. A further indicator of risk was the persistence of increased amounts of retinyl palmitate in the plasma of severely affected individuals 24 h after its ingestion with the meal. These observations are consistent with the proposal that the clearance of chylomicrons and their remnants is impaired in coronary atherosclerosis. Fenofibrate reduced alimentary lipemia following the fat load in both normo- and hypercholesterolemic subjects. This was associated with a 10% rise in plasma HDL cholesterol levels. The improvement in chylomicron catabolism probably derived from a 37% increase (P less than 0.001) in lipoprotein lipase activity induced by fenofibrate. Hepatic lipase on the other had was only slightly affected by treatment.

Left ventricular hypertrophy and mortality in hypertension: an analysis of data from the Glasgow Blood Pressure Clinic

Three thousand seven hundred and eighty-three patients with non-malignant hypertension attending the Glasgow Blood Pressure Clinic between 1968 and 1983 were followed prospectively for an average of 6.5 years. Left ventricular hypertrophy (LVH) was present at the outset in 34.5% of the men, and 12.8% had ST-T changes. The corresponding figures for women were 21.5% and 8.8%. The prevalence of LVH increased with the severity of hypertension and was higher for a given blood pressure level in men than in women. All-cause age-adjusted mortality, expressed as deaths per 1000 patient-years, was 27.6 for men with normal electrocardiographs, 43.2 for men with LVH only (P less than 0.001) and 56.9 for men with LVH and ST-T changes (P less than 0.001). Similar trends were seen in women. The excess risk associated with LVH, with or without ST-T changes, could not be explained by age, increased blood pressure at referral to the clinic, or smoking habit, when these factors were considered either separately or in combination (regression analysis). Thus, our study demonstrates that LVH, with or without ST-T changes is an independent risk factor for mortality in hypertensive patients.

Acipimox in combination with low dose cholestyramine for the treatment of type II hyperlipidaemia

1. This study was designed to examine the effects of acipimox 250 mg three times daily and cholestyramine 4 g three times daily on plasma lipids and lipoproteins in 28 hypercholesterolaemic individuals in a prospective double-blind placebo controlled parallel group fashion. 2. Combined treatment with the two agents produced a mean reduction of 27% in plasma total cholesterol and a 32% fall in LDL cholesterol. Plasma triglyceride was reduced by 13% due to a 38% decrement in VLDL cholesterol. 3. In comparison treatment with cholestyramine alone resulted in a 12% fall in plasma cholesterol and a 15% fall in LDL cholesterol. In this group triglycerides and VLDL showed no significant change. 4. Studies of HDL subfraction mass showed that the addition of acipimox to resin therapy produced a mean increment of 45% in HDL2. 5. These results demonstrate the effectiveness of such a well tolerated low dosage combination therapy.

Simultaneous measurement of left ventricular function and perfusion

A new radiopharmaceutical, methylisobutyl isonitrile (MIBI), has been developed as a technetium-99m-labelled alternative to thallium 201 for myocardial imaging. By virtue of the high specific activity of 99mTc, some 600 MBq may be administered as a 0.3 ml bolus, permitting the acquisition of a first-pass nuclear angiogram at rest and at peak exercise. The agent was assessed in ten sequential patients referred for routine cardiac catheterisation, who also underwent an exercise electrocardiographic (ECG) test. Good quality nuclear angiograms, planar perfusion and tomographic perfusion images were obtained; the results correlated well with the catheterisation data. Of 30 myocardial segments for which wall motion was judged normal/abnormal from the nuclear angiogram, results concordant with contrast studies were obtained in 27 (90%). In the case of the 50 segments analysed from the perfusion images, concordant results were obtained in 43 (86%) from the planar studies and in 42 (84%) from the tomographic studies. All normal segments were classified correctly.

The effects of felodipine in angina pectoris

The clinical response to felodipine, in addition to a beta-blocker, was evaluated and compared with placebo in this double-blind cross-over study. Twenty patients with exertional angina pectoris completed the study. Felodipine reduced the number of angina attacks and the Glyceryl Trinitrate (GTN) consumption. The median exercise capacity was increased 33% after 4 weeks' felodipine treatment compared with placebo. At maximal exercise, systolic blood pressure and rate pressure product were reduced by felodipine while no change was seen in heart rate or ST-depression. Felodipine reduced both supine and erect blood pressure. The mean supine blood pressure at rest was 138/82 mm Hg after four weeks' placebo treatment compared with 114/71 mmHg after felodipine 5-10 mg b.i.d. Felodipine has overall a modest but significant anti-anginal benefit when combined with a beta-blocker.

The safety of felodipine

Hypertensive patients, particularly the elderly, may often suffer from other diseases. Therefore, antihypertensive compounds should not negatively affect such disorders. Felodipine is a calcium antagonist that has potentially beneficial effects in angina pectoris and congestive heart failure. Further, it does not adversely affect lung function in asthmatic patients or glucose tolerance in patients with diabetes. Preliminary investigations also indicate that felodipine has no negative influence on plasma lipid levels. Although felodipine seems to be safe in most patients, treatment with felodipine should at present be avoided in pregnant women, since digital anomalies have been observed in rabbit fetuses. The adverse effects seen during treatment with felodipine are usually mild and transient and generally related to the vasodilatory action of the drug, the most common being ankle edema, headache, flushing, dizziness, and palpitations. The only significant drug interactions with felodipine occur with inducers and inhibitors of the cytochrome P-450 system, which is responsible for the metabolism of felodipine.

A comparison of amlodipine, verapamil and placebo in the treatment of mild to moderate hypertension. Amlodipine Study Group

This is a double blind parallel group comparison in patients with mild-moderate hypertension, of amlodipine, verapamil and placebo. One hundred and sixty patients entered the double blind phase. In the amlodipine group the mean supine and standing systolic pressures at week 12 were respectively lowered from baseline by 11.9 mmHg and 11.3 mmHg more than for the placebo group (P = 0.0001). Diastolic blood pressures were also significantly reduced. With verapamil the mean supine and standing systolic blood pressure at week 12 were reduced by 7.7 mmHg and 8.3 mmHg more on verapamil than on placebo (P = 0.0083). Blood pressures of the amlodipine group were lower 24 hour post-dose than verapamil 12 hours post dose. The responder rates after eight weeks of double blind therapy were amlodipine 72.3%, verapamil 47.8% and placebo 32.6%. Body weight after verapamil increased by mean 0.9 kg, after amlodipine by 0.2 kg and after placebo decreased by 0.2 kg. Six patients were withdrawn because of adverse effects (3 amlodipine, 2 verapamil, 1 placebo). The number of patients with adverse effects possibly related to therapy were 22/53 for amlodipine, 19/54 for verapamil and 14/53 for placebo. Both drugs were, overall, well tolerated, effective and had no unexpected adverse effects.

Pathophysiologic assessment of left ventricular hypertrophy and strain in asymptomatic patients with essential hypertension

To investigate the significance of the electrocardiographic (ECG) pattern of left ventricular hypertrophy and strain, two groups of asymptomatic patients with essential hypertension were compared. The patients were similar in terms of age, smoking habit, serum cholesterol and blood pressure levels, but differed in the presence (Group I, n = 23) or absence (Group II, n = 23) of the ECG pattern of left ventricular hypertrophy and strain. Group I patients had significantly more episodes of exercise-induced ST segment depression (14 versus 4, p less than 0.05) and reversible thallium perfusion abnormalities (11 of 23 versus 3 of 23, p less than 0.05) despite similar exercise capacity and absence of chest pain. Nonsustained ventricular tachycardia was detected on 24 h ambulatory ECG monitoring in two patients in Group I, but no patient in Group II. Coronary arteriography performed in 20 Group I patients demonstrated significant coronary artery disease in 8 patients. This study has shown that there is a subgroup of hypertensive patients with ECG left ventricular hypertrophy and strain who have covert coronary artery disease. This can be detected by thallium perfusion scintigraphy, and may contribute to the increased risk known to be associated with this ECG abnormality.

Comparison of enalapril and atenolol in mild to moderate hypertension

PURPOSE

Short-term therapy with angiotensin converting enzyme (ACE) inhibitors for hypertension is effective and well tolerated, and compared with beta blockers, may cause fewer adverse reactions. Furthermore, enalapril has been observed to have a greater effect on systolic blood pressure than beta blockers. We therefore decided to compare the ACE inhibitor enalapril and the beta blocker atenolol as monotherapy in a double-blind study of patients with mild to moderate hypertension.

PATIENTS AND METHODS

After a four-week placebo run-in period, 162 patients were allocated randomly to receive atenolol (50 to 100 mg daily) or enalapril (20 to 40 mg daily) for 12 weeks. To assess the influence of these drugs on quality of life, a series of psychologic tests was performed, and a subset of patients also underwent treadmill exercise and pulmonary function tests.

RESULTS

In 147 patients who completed the study, enalapril reduced supine blood pressure by 19/12 mm Hg, compared with 9/7 mm Hg for atenolol (p less than 0.001/p less than 0.005). The modest blood pressure response to atenolol was not due to poor compliance. A target blood pressure of 140/90 mm Hg or less was achieved by 35 percent of enalapril-treated atenolol (p less than 0.01). The frequency and severity of adverse effects with the two drugs were similar, and few important differences emerged from the quality-of-life assessments.

CONCLUSION

At the doses used, enalapril induced a greater short-term blood pressure response than atenolol; long-term studies of its safety and efficacy are required.

Effect of combined therapy with bezafibrate and cholestyramine on low-density lipoprotein metabolism in type IIa hypercholesterolemia

This study was designed to examine the influence of combined therapy with bezafibrate and cholestyramine on plasma lipids and on the metabolism of low-density lipoprotein (LDL). Twenty-one type II hyperlipidemic subjects were treated with bezafibrate alone or in combination with cholestyramine. A 17% fall in plasma cholesterol was seen with bezafibrate, and addition of cholestyramine produced an additional 9% reduction in this lipid. The effectiveness of the combination therapy was mediated through a 47% decrement in very-low-density lipoprotein (VLDL) cholesterol, a 37% reduction in LDL cholesterol, and a 15% increase in the level of that lipid in high-density lipoprotein (HDL). Plasma triglyceride fell 43% when bezafibrate was given alone, and did not change further when cholestyramine was added. The metabolism of LDL was examined in nine individuals to determine the mechanism underlying these changes. No significant modification in LDL synthetic rate was incurred with either drug regimen, whereas the fractional catabolic rate of LDL via the receptor pathway rose by 66% with bezafibrate alone and by 79% (compared to baseline) following the addition of cholestyramine. Plasma HDL rose during bezafibrate therapy due to an increase in the HDL3 subfraction. Compositional analysis of LDL showed a reduction in cholesterol ester and an increase in triglyceride and phospholipid during combined drug therapy. These results demonstrate that combined therapy with bezafibrate and cholestyramine markedly improves the lipoprotein profile in type II hyperlipidemia. The drugs appear to be complementary in their actions upon the LDL receptor pathway.

The effect of a long-acting somatostatin analogue on portal and systemic haemodynamics in cirrhosis

Current interest in the pharmacological manipulation of portal pressure centres on the long-acting somatostatin analogue SMS 201-995. Nine haemodynamically stable cirrhotic patients who had previously bled from oesophageal varices had wedged and free hepatic venous pressures and cardiac index measured, using a Swan-Ganz catheter, before and at 60, 120 and 180 min after beginning a 60-min infusion of 25 microgram/h of SMS 201-995. Seven clinically similar patients had the same measurements performed without SMS 201-995. In all patients cardiac index was found to decrease and systemic vascular resistance increase at 60 min, although heart rates and arterial blood pressures were unchanged. The group given SMS 201-995 was significantly different from the control group in sustaining a fall in wedged hepatic venous pressure and trans-hepatic venous gradient at 60 min. SMS 201-995 causes a fall in portal pressure without a significant systemic haemodynamic effect.

Regression of electrocardiographic left ventricular hypertrophy following treatment of primary hyperaldosteronism

The electrocardiograms (ECGs) of a series of 34 patients with primary hyperaldosteronism (PHA), 17 treated surgically (group I) nine treated medically (group II) and eight treated with/by both surgery and drug therapy (group III) were analysed to determine whether the treatment of PHA resulted in an improvement in the ECG changes of left ventricular hypertrophy (LVH) and also whether there was a difference in this improvement between medically and surgically treated patients. There was a significant reduction of blood pressure in the group as a whole (186/111 to 141/95 mmHg, P less than 0.001) and within each of the treatment groups (group I 183/108 to 137/98 mmHg, group II 188/112 to 147/93 mmHg, group III 193/115 to 144/92 mmHg). This reduction within each group was of a similar magnitude. There were reductions in both precordial voltages (SV1 + RV5) from 3.68 mV to 2.79 mV (P less than 0.01) and in the number of patients with ECG LVH from 15 to 8 (P less than 0.05). Again the reductions were of similar magnitude in each of the groups: group I 3.78 to 2.77 mV, group II 3.78 to 2.84 mV, group III 3.39 to 2.77 mV. Thus the improvement in blood pressure achieved by the treatment of PHA is accompanied by a reduction in precordial voltages and the number of patients with ECG-LVH. This improvement is independent of the type of treatment used.

Thrombin and plasmin activity in coronary artery disease

Basal plasmin and thrombin activity in plasma were assessed by radioimmunoassay of the fibrinogen derivatives containing the sequence B beta 15-42 and of fibrinopeptide A respectively in a cross sectional controlled study of men with coronary artery disease. Compared with healthy controls (n = 33) men with angiographically defined coronary artery disease (n = 98) had a modest but significant increase in concentrations of fibrinopeptide A, indicating an activated coagulation system. Concentrations of B beta 15-42 were similar in those with coronary artery disease and in the controls. The enhanced thrombin activity in coronary artery disease is in keeping with current evidence suggesting an association between coronary artery disease and a hypercoagulable state.

24-hour control of blood pressure by once daily doxazosin: a multicentre double-blind comparison with placebo

The antihypertensive efficacy of the new, once daily, alpha 1-adrenoceptor inhibitor, doxazosin, was compared with placebo in 40 patients with mild to moderate hypertension. Following a dose titration the mean final daily doxazosin dose in 20 patients was 13.1 mg. Through-the-day blood pressure control was assessed by frequent measurements during 24 h hospitalisation in the 9 th week of double-blind treatment compared with similar measurements made during a 2 week single-blind placebo run-in. Mean reductions in standing and supine systolic and diastolic blood pressure during doxazosin treatment were statistically significantly greater than during placebo treatment at most hourly time points during the 24 h post-dose period. Twenty-four post-dose the mean falls in standing and supine diastolic blood pressure during doxazosin treatment were statistically significant when compared with placebo. Adverse effects during doxazosin treatment were generally minor and were tolerated or disappeared with continued therapy. No patients were withdrawn from the study due to adverse effects. We conclude that once daily doxazosin provides smooth and effective blood pressure control throughout a 24 h post-dose period.

Comparison of amlodipine and verapamil in the treatment of mild to moderate hypertension

One hundred sixty patients with mild to moderate essential hypertension entered this double-blind parallel group comparison of amlodipine, verapamil, and placebo. Sixteen centers from the United Kingdom and Norway participated in this multicenter study. Administration of amlodipine (2.5 mg with adjustment to 5.0 mg and to 10.0 mg o.d.) or verapamil (80 mg b.i.d. titrating to 160 mg b.i.d.) for 8 weeks to patients with mild to moderate hypertension was associated with clinically important and statistically significant decreases in both supine and standing blood pressures. After 8 weeks of double-blind therapy, the mean (amlodipine-placebo) difference in the falls from baseline in blood pressures measured 24 h postdose were -11.9/-7.0 mm Hg (supine) and -11.4/-6.3 mm Hg (standing). The corresponding figures were -7.7/-4.6 mm Hg and 8.3/-4.0 mm Hg for verapamil (12 h postdose). Mean reductions from baseline of the amlodipine group exceeded those of the verapamil group by 2-4 mm Hg for all pressure measurements, and this difference was statistically significant for diastolic blood pressures. Responder rates were 72, 48, and 33% for amlodipine, verapamil, and placebo, respectively. Mean doses at 8 weeks were 9.1 mg (amlodipine) and 296 mg (verapamil). There were no significant changes in pulse rate. Both active drugs maintained their antihypertensive effect through the day (0-12 h postdose) with amlodipine showing a sustained 24-h effect. Twenty-two patients in the amlodipine, 19 in the verapamil, and 14 in the placebo groups had side effects possibly related to treatment.(ABSTRACT TRUNCATED AT 250 WORDS)