Role of ambulatory blood pressure monitoring in the assessment and prognosis of patients with borderline hypertension.

The role of ambulatory blood pressure (ABP) monitoring in the assessment of mild/borderline hypertension (BHT) is unclear. The aim of this study was to test the hypothesis that measurement of ABP in borderline hypertensives differentiates patients with true mild hypertension from those with isolated clinic hypertension (raised office BP but normal ABP) and that a raised ABP identifies a subgroup who are more likely to progress to and require treatment over 1 year. Consecutive untreated patients with BHT (n = 127, 44 +/- 13 years, 45% male) were divided into two groups according to awake ABP: Group 1 (normal ABP < or = 136/86, n = 48), and Group 2 (abnormal ABP > 136/86, n = 79). Left ventricular mass index (LVMI) was greater (116 +/- 30 vs 101 +/- 25 g/m2, p < 0.01) and the proportion of patients with an increased LVMI was significantly higher (34% vs 17%, p = 0.05) in Group 2. During 1 year of follow-up, significantly more patients in Group 2 (34%) required antihypertensive treatment compared with Group 1 (8%, p = 0.01). ABP monitoring usefully discriminates between patients with true BHT and those with isolated clinic hypertension. An elevated awake ABP on initial assessment is associated with a higher LVMI and a greater likelihood of progression to moderate hypertension requiring pharmacological treatment.

Variability of diurnal changes in ambulatory blood pressure and nocturnal dipping status in untreated hypertensive and normotensive subjects.

An absent or diminished blood pressure (BP) fall during sleep (so-called "nondipping") has been associated with a higher risk of cardiovascular complications, but the long-term reproducibility of dipper status and the relationship between diurnal changes in BP and perceived sleep quality have not been previously documented in untreated hypertensive patients. Ambulatory BP (ABP) and dipping status were examined in 79 subjects (69 hypertensives and 10 normotensives) at 0, 6, and 12 months. Fifty-six percent of subjects had no change in their dipping status, the majority (53%) dipping normally on all three occasions. However, 44% of patients had variable dipping status, and normal nighttime dipping in BP was observed more often when patients perceived their sleep quality to be good during the period of ABP recording. These results highlight significant intrasubject variability in the diurnal fluctuations in ABP and dipper status, which may in part reflect day-to-day variations in sleep disturbance during ABP monitoring. Classifying hypertensive patients into dippers or nondippers on the basis of a single ABP recording is unreliable and potentially misleading.

Clinical implications of white coat hypertension: an ambulatory blood pressure monitoring study.

Within routine clinical practice, white coat hypertension (where blood pressure is persistently higher in the presence of the doctor or nurse but normal outside the medical setting) makes the diagnosis and management of hypertension difficult. There are conflicting data regarding the prevalence and significance of white coat hypertension. This study has used ambulatory blood pressure monitoring to detect the presence of white coat hypertension in 186 patients referred to an out-patient hypertension unit. The presence of white coat hypertension was defined as an average office blood pressure (measured on three occasions over a 2-month period) of >140/90 mm Hg and an ambulatory awake blood pressure < or = 136/86 mm Hg. The prevalence of white coat hypertension in those patients with borderline hypertension (diastolic blood pressure 90-99 mm Hg) and those with mild-to-moderate hypertension (diastolic blood pressure > or = 100 mm Hg) was determined. Echocardiography was used to assess left ventricular mass index in patients with and without white coat hypertension. The prevalence of white coat hypertension in the total group was 23%. However, the prevalence was higher (33%) in those patients with borderline hypertension compared to 9% of those patients with mild-to-moderate hypertension. There was a statistically significant increase in left ventricular mass index in patients with no evidence of white coat hypertension (125 gm/m2) compared to those with white coat hypertension (102 gm/m2). We conclude that, if office blood pressure is used to identify patients with hypertension who may require treatment, some patients will be incorrectly diagnosed and may be treated inappropriately. We recommend that ambulatory blood pressure monitoring is used in the routine assessment of all newly diagnosed hypertensive patients. Furthermore, we recommend echocardiography in patients with borderline hypertension as some will already have an increased left ventricular mass index.

Twenty-four hour ambulatory blood pressure: a sample from a normal British population.

The aims of this study were to determine 24 h blood pressure (BP) levels in a sample taken from a normal British population, and to investigate factors contributing to variation within the sample. Two hundred and eighty-two Caucasian subjects, with no known hypertension or cardiovascular disease were recruited from local light industry and a general practice population. Office and 24 h BPs were measured. The mean office BP was 120/75, ambulatory mean awake 115/72 and mean asleep 97/58 mm Hg. Males had a small but significantly higher mean office and awake BP but there were no differences in asleep BP. Multiple step-wise regression with age, gender, weight and height showed age to be the best predictor of variation in office BP and awake and asleep diastolic BP. However, age accounted for only a small amount of the variation and did not contribute towards the variation in systolic BP. The two standard deviation upper limits for this population for awake, asleep and overall BP were 136/86, 121/73 and 131/82 mm Hg, respectively. In conclusion, these data providing information on 24 h BP in a healthy British population may be of value in the clinical interpretation of 24 h ambulatory BP recordings in patients with suspected hypertension.

Reduction in treatment delay by paramedic ECG diagnosis of myocardial infarction with direct CCU admission.

OBJECTIVES: To establish the feasibility of training paramedics of diagnose acute myocardial infarction by ECG before hospital admission and whether direct paramedic coronary care admission, arranged by very high frequency (VHF) radio communication with the coronary care unit (CCU), would reduce delay of thrombolysis treatment. DESIGN: Prospective controlled study. SETTING: District general hospital CCU and a local district ambulance paramedic service. PATIENTS: 124 patients with ECG evidence of myocardial infarction or ischaemia admitted directly to the CCU by the paramedic service were compared with 123 patients admitted by the emergency department and subsequently transferred to the CCU. MAIN OUTCOME MEASURES: ECG diagnostic accuracy by paramedics, and interval durations for CCU admission and thrombolysis. RESULTS: ECG diagnostic accuracy by the paramedics was 87.5% in the training phase and 92% in admission. The total call to thrombolysis interval was reduced from 154 to 93 minutes and the "door to needle" interval was reduced from 97 to 37 minutes. CONCLUSIONS: Trained paramedics can reliably diagnose myocardial infarction by ECG. The use of a direct admission procedure, by a VHF radio link to the CCU, substantially reduces the time interval for thrombolytic treatment after acute myocardial infarction.

Review: calcium antagonists and diuretics; a useful combination in the management of hypertension?

The use of the combination of a calcium antagonist with a thiazide diuretic for the treatment of hypertension has been the subject of much debate over a number of years. Early studies, with few subjects, demonstrated little benefit, but more recent research using larger numbers of subjects has shown quite clear additional antihypertensive effects of this combination. Combination therapy has an important role in the treatment of patients who do not respond to monotherapy, and the combination of a calcium antagonist and thiazide diuretic may be useful in the successful treatment of these patients.

Double-blind, parallel, comparative multicentre study of a new combination of diltiazem and hydrochlorothiazide with individual components in patients with mild or moderate hypertension.

OBJECTIVE: To compare the antihypertensive efficacy and tolerability of a new combination preparation of diltiazem (150 mg) and hydrochlorothiazide (12.5 mg) with the individual constituents in patients with mild/moderate hypertension. DESIGN: Multi-centre, double-blind, randomised parallel group study. PATIENTS: Seventy-one patients with essential hypertension were recruited to the study. TREATMENT: Following completion of the placebo run-in period 63 patients fulfilled the prerandomisation criteria and entered the 10 week treatment period. Patients were randomised to receive either the combination preparation (D 150 mg/H 12.5 mg), diltiazem (150 mg) or hydrochlorthiazide (12.5 mg). The dosage was increased in three patients who had not attained target blood pressure (BP) control after 6 weeks. OUTCOME MEASURES: Response to treatment assessed by change from baseline in clinic and 24 h ambulatory BP. RESULTS: The proportion of patients achieving target BP (a reduction in resting supine diastolic blood pressure (DBP) to below 90 mm Hg or a reduction of 10 mm Hg from baseline) was 80% in the combination group, 55% in the diltiazem group, and 38% in the hydrochlorothiazide group. The respective figures for reduction in supine DBP from baseline were 13.5 mm Hg, 11.2 mm Hg and 5.9 mm Hg. A similar treatment order appeared throughout each of the efficacy variables. BP control throughout the 24 h dosing interval was demonstrated by ambulatory BP monitoring. Each treatment was well tolerated. CONCLUSION: This study provides clear evidence of the efficacy of combination therapy with diltiazem and hydrochlorothiazide in the management of patients with hypertension.

Raised ambulatory blood pressure in type 1 diabetes with incipient microalbuminuria.

Whether raised blood pressure precedes, follows or develops in parallel with the onset of microalbuminuria, remains unclear. Previous studies, using conventional blood pressure recordings, have yielded discrepant results. Ambulatory blood pressure (ABP) monitoring detects borderline hypertension more reliably, and correlates more closely with end-organ damage. We have therefore compared ABP and left ventricular dimensions in normotensive insulin-dependent diabetic patients with or without microalbuminuria, and matched nondiabetic control subjects. Those diabetic patients with microalbuminuria, and to a lesser extent those without, had higher 24 h mean arterial blood pressure than matched non-diabetic control subjects, with corresponding increases of left ventricular mass, interventricular septal width and posterior wall thickness. These observations suggest that raised arterial blood pressure is present at an early stage of 'incipient' microalbuminuria.

How reliable is the electrocardiogram in detecting left ventricular hypertrophy in hypertension?

This paper assesses the sensitivity and specificity of the electrocardiogram in detecting left ventricular hypertrophy in 75 hypertensive patients. Each patient underwent a 12 lead electrocardiogram and echocardiogram. Left ventricular mass index, using echocardiogram, was calculated according to the Penn convention and left ventricular hypertrophy was assessed by standard electrocardiographic criteria. The electrocardiogram was found to be very specific but insensitive in the detection of left ventricular hypertrophy as compared with the echocardiogram. Other non-voltage dependent markers appeared to have similar reliability. We conclude that the electrocardiogram may be unreliable in the detection of left ventricular hypertrophy in hypertensive patients. Accurate assessment of left ventricular hypertrophy, in these patients should be by echocardiography.

Type III collagen mutations cause fragile cerebral arteries.

Premature vascular aneurysms and fragility of cerebral arteries are commonly associated with type III collagen mutations and physical signs suggesting a generalized abnormality of connective tissue. Sometimes these traits are clearly genetically transmitted. Here we present seven examples of early cerebrovascular aneurysms or fragility including five examples of carotid cavernous sinus aneurysms. With one exception in which we suspect the mutation is too small to be detected, all of them had easily visible abnormalities of their type III collagen proteins. Further work in progress will eventually allow the characterization of their mutations at gene sequence level and will be followed by the ability to prevent transmission of the mutant genes in these families.

Prediction of "critical" coronary disease: are the "Consensus Conference" guidelines adequate?

Presenting features of 100 patients with significant left main coronary stenosis (LMCS) were reviewed. All presented with angina--on minimal exertion in 45, moderate exertion in 38, and severe exertion in 6--and 11 had unstable angina. Although the resting ECG was normal in 44, exercise testing was positive in 92% of patients tested. The authors conclude that symptoms and the resting ECG alone are unhelpful in predicting "critical" coronary disease. However, application of a management plan similar to that suggested by the Consensus Conference on coronary artery surgery would have selected the vast majority of such patients for angiography.

Blood pressure variability in health, hypertension and autonomic failure.

24h intra-arterial pressure monitoring was used to examine blood pressure variability in 5 normal volunteers, 137 subjects with suspected or established essential hypertension and 9 subjects with autonomic failure. Subjects with autonomic failure showed increased short-term blood pressure variability while active but reduced values at rest. Heart rate variability was low at all times. 24h recordings were reduced to hourly mean values and two indices of variability derived - day-night difference and average hourly change. For blood pressure, subjects with autonomic failure showed negative values of the former but high values of the latter; both indices of heart rate variability were low. In the remaining group, the relationship of these indices to constitutional factors, mean blood pressure and indices of physical activity during the study was explored. Day-night difference in systolic pressure was negatively correlated with mean pressure and average hourly change positively related to age. No other relationship was significant.

The safety of ambulatory intra-arterial pressure monitoring: a clinical audit of 1000 studies.

Between 1973 and 1981 1000 successful studies involving ambulatory monitoring of intra-arterial blood pressure were performed using percutaneous cannulation of the brachial artery. We have reviewed the clinical effects of these studies and 35 other cases where attempted cannulation was unsuccessful. One major complication occurred, when an infected haematoma arising at the cannulation site led to the formation of a false aneurysm. In only one other case was distal pulsation diminished following the study. There were 157 reported "minor" complications in 122 studies, including haematoma, haemorrhage, transient paraesthesiae in median nerve territory, and evidence of micro-emboli. A limited study using pulsed wave Doppler ultrasound revealed no significant alteration in arterial lumen size or flow in 20 subjects. The procedure was therefore associated with a much smaller incidence of clinical problems than has been reported with other investigations involving cannulation of the brachial artery.

Haemostatic variables and the outcome of myocardial infarction.

In a study of 272 patients with myocardial infarction (MI) the 68 who died within 1 year had significantly higher levels of factor VIIIR:Ag, factor VIII:C, fibrinogen, alpha 1 antitrypsin and alpha 2 macroglobulin than those who survived. The mean white cell count (WCC) and peak creatine kinase (CK) were also significantly higher in those who died compared with the survivors. There was considerable intercorrelation between many of the haemostatic variables, WCC and CK as well as between many of the clinical predictors of outcome and the laboratory variables. The differences in haemostatic variables between those who died and those who survived may merely reflect the size of the infarct; alternatively, the haemostatic system may influence prognosis following an MI.