Ambulatory blood pressure monitoring and echocardiography--noninvasive techniques for evaluation of the hypertensive patient

Methods of Blood Pressure Measurement to Predict Hypertension-Related Cardiovascular Morbidity and Mortality

PURPOSE OF REVIEW

As the evidence on different blood pressure phenotypes and their cardiovascular risks evolve, it is imperative to evaluate the reliability of office blood pressure (OBP), ambulatory blood pressure (ABP), and home blood pressure (HBP) measurements and their associations with cardiovascular morbidity and mortality.

RECENT FINDINGS

HBP is more reliable in diagnosis of hypertension than OBP or ABP. HBP correlates better with left ventricular mass index (LVMI). Increasing systolic HBP is associated with a higher risk of all-cause mortality, cardiovascular mortality, and cardiovascular events. An elevated systolic ABP is also associated with a higher risk of cardiovascular events and mortality. ABP is a better predictor of cardiovascular events than OBP in diabetics. ABP and HBP furnish additional information beyond OBP. They correlate better with cardiovascular outcomes and are more helpful with monitoring therapy than OBP. Comparative effectiveness studies of all three methods associating with cardiovascular outcomes are warranted.

Blood Pressure and Left Ventricular Hypertrophy in Patients on Different Peritoneal Dialysis Regimens

Objective

To examine the relation between the results of ambulatory 24-hour blood pressure monitoring (ABPM) and left ventricular mass index (LVMI), then to find the independent determinant for left ventricular hypertrophy (LVH) in peritoneal dialysis (PD) patients. Finally, to evaluate the differences in the clinical and cardiovascular characteristics between patients on continuous ambulatory PD (CAPD) and continuous cyclic PD (CCPD).

Design

An open, nonrandomized, cross-sectional study.

Setting

Divisions of nephrology and cardiology in a medical center.

Patients

Thirty-two uremic patients on maintenance PD therapy (22 patients on CAPD, and 10 on CCPD) without anatomical heart disease or history of receiving long-term hemodialysis.

Interventions

Home blood pressure (BP) and office BP were measured using the Korotkoff sound technique by sphygmomanometer. ABPM was employed for continuous measurement of BP. Echocardiography was performed for measurement of cardiac parameters and calculation of LVMI.

Main Outcome Measures

Multivariate logistic regression analysis was performed for independent determinant of LVH in PD patients. The differences in clinical and cardiovascular characteristics between CAPD and CCPD patients were compared.

Results

Simple regression analysis showed positive correlations between LVMI and the duration of hypertension, ambulatory nighttime BP/BP load/BP load > 30%, serum phosphate, calcium–phosphate product, ultrafiltration (UF) volume, and percentage of UF volume during the nighttime. A negative correlation was noted between LVMI and dipping. In multiple regression analysis, the duration of hypertension was the only variable linked to LVMI. In multivariate logistic regression analysis, only ambulatory nighttime systolic BP load > 30% had an independent association with LVH. There were correlations between office/home BP and ambulatory 24-hour BP. In addition, CCPD patients had higher LVMI, UF volume during the nighttime, and percentage of UF volume during the nighttime than those of CAPD patients.

Conclusions

In this study, ambulatory nighttime systolic BP load > 30% had an independent association with LVH. Office and home BP measurements were correlated with ABPM in PD patients. The result that CCPD patients had a higher LVMI than CAPD patients may be due to a relative volume overload during the daytime in CCPD patients.

Left ventricular hypertrophy and blood pressure control in automated and continuous ambulatory peritoneal dialysis patients

Hypertension, non-dipper blood pressure (BP) pattern and decrease in daily urine output have been associated with left ventricular hypertrophy (LVH) in peritoneal dialysis (PD) patients. However, there is lack of data regarding the impact of different PD regimens on these factors. We aimed to investigate the impact of circadian rhythm of BP on LVH in end-stage renal disease patients using automated peritoneal dialysis (APD) or continuous ambulatory peritoneal dialysis (CAPD) modalities. Twenty APD (7 men, 13 women) and 28 CAPD (16 men, 12 women) patients were included into the study. 24-h ambulatory blood pressure monitoring (ABPM) and transthoracic echocardiography besides routine blood examinations were performed. Two groups were compared with each other for ABPM measurements, BP loads, dipping patterns, left ventricular mass index (LVMI) and daily urine output. Mean systolic and diastolic BP measurements, BP loads, LVMI, residual renal function (RRF) and percentage of non-dippers were found to be similar for the two groups. There were positive correlations of LVMI with BP measurements and BP loads. LVMI was found to be significantly higher in diastolic non-dippers compared to dippers (140.4 ± 35.3 vs 114.5 ± 29.7, respectively, P = 0.02). RRF and BP were found to be independent predictors of LVMI. Non-dipping BP pattern was a frequent finding among all PD patients without an inter-group difference. Additionally, higher BP measurements, decrease in daily urine output and non-dipper diastolic BP pattern were associated with LVMI. In order to avoid LVH, besides correction of anemia and volume control, circadian BP variability and diastolic dipping should also be taken into consideration in PD patients.

Hypertension 2005: an evidence-based approach to diagnosis and treatment – an American perspective

Midway into the first decade of the 21st century, evidence-based medicine has become the predominant methodology for the education and practice of medicine. In the ascent to this pre-eminent position, evidence-based medicine has challenged several methodologies through which medicine was taught and practiced throughout the 20th century, including the clinical anecdote, the concept that medicine is an art, the notion that the physician acts as the filter through which medical knowledge is individualized for the patient, and to some extent, the application of principles of pathophysiology to guide individual patient care. Indeed, it appears that in many cases, this mechanism-based approach to disease has been replaced by a broad strokes population-based approach based on outcomes research. However, as in the law, evidence is open to interpretation, varying opinion and nuance. Perhaps nowhere is this more evident than in the field of hypertension, which arguably can be credited with developing the field of evidence-based medicine with randomized clinical trials in the early 1960s and early adaptation and promotion of outcomes-based research, beginning with the first Joint National Committee report on prevention, detection, evaluation and treatment of high blood pressure in the 1970s. The purpose of this chapter is to review the evidence in the diagnosis and treatment of essential hypertension, focusing on the following areas. First, use of ambulatory and home blood pressure monitoring as diagnostic and prognostic tools; second, recent clinical trials in the treatment of essential hypertension that form the basis of evidence-based therapeutics; and third, presentation of the key features of the Joint National Committee (JNC) 7, which forms the current basis of treatment for essential hypertension.

Respiratory changes in the E/A wave pattern can be an early sign of diastolic dysfunction: an echocardiographic long-term follow-up study

BACKGROUND

The left ventricular filling pattern may show changes during respiration, which are generally used in the diagnosis of diastolic dysfunction. The clinical importance of the respiratory E/A wave pattern change has been investigated in a limited number of studies. The aim of the present study was to assess the diastolic function of hypertensive patients with respiratory changes in mitral flow over a long-term follow-up period.

MATERIAL/METHODS

Our study included 107 newly diagnosed and untreated hypertensive patients (49 males; mean age, 46±10 years) with respiratory changes during transthoracic echocardiography (TTE). In addition, the patient group was classified into 2 groups according to the change in E/A pattern by the Valsalva maneuver. After a mean follow-up period of 44±7 month, 90% of the hypertensive patients and the entire control group were re-examined.

RESULTS

Relaxation abnormalities developed in 84% of the patients (58/80) in the Valsalva-positive group after the follow-up period. The frequency of relaxation abnormalities was 60% in the Valsalva-negative group and 3.1% in the control group (p<0.001). Based on multivariate regression analysis, the echocardiographic predictors of the development of relaxation impairment were mitral E velocity, A velocity, deceleration time, isovolumetric contraction time, E/E' ratio, and the presence of respiratory change. The most important parameter for the development of an abnormal relaxation pattern was the presence of respiratory change after adjustment according to the changes with the Valsalva maneuver.

CONCLUSIONS

Respiratory change in mitral flow can be evaluated as an early sign of diastolic dysfunction in patients with hypertension.

Comparison of Blood Pressure Control and Left Ventricular Hypertrophy in Patients on Continuous Ambulatory Peritoneal Dialysis (CAPD) and Automated Peritoneal Dialysis (APD)

This study aimed to investigate the influence of different peritoneal dialysis regimens on blood pressure control, the diurnal pattern of blood pressure and left ventricular hypertrophy in patients on peritoneal dialysis. Forty-four patients undergoing peritoneal dialysis were enrolled into the study. Patients were treated with different regimens of peritoneal dialysis: 26 patients on continuous ambulatory peritoneal dialysis (CAPD) and 18 patients on automated peritoneal dialysis (APD). All patients performed 24-hour ambulatory blood pressure monitoring (ABPM) and echocardiography. Echocardiography was performed for measurement of cardiac parameters and calculation of left ventricular mass index (LVMI). There were no significant differences in average of systolic and diastolic blood pressure during 24-hour, daytime, and nighttime between CAPD and APD groups. There were no significant differences in diurnal variation of blood pressure, systolic and diastolic blood pressure load, and LVMI between CAPD and APD groups. LVMI was associated with 24 hour systolic blood pressure load (r = 0.311, P < 0.05) and daytime systolic blood pressure load (r = 0.360, P < 0.05). In conclusion, this study found that there is no difference in blood pressure control, diurnal variation of blood pressure and left ventricular hypertrophy between CAPD and APD patients. The different peritoneal dialysis regimens might not influence blood pressure control and diurnal variation of blood pressure in patients on peritoneal dialysis.

Principles and techniques of blood pressure measurement

Although the mercury sphygmomanometer is widely regarded as the gold standard for office blood pressure measurement, the ban on use of mercury devices continues to diminish their role in office and hospital settings. To date, mercury devices have largely been phased out in United States hospitals. This situation has led to the proliferation of nonmercury devices and has changed (probably forever) the preferable modality of blood pressure measurement in clinic and hospital settings. In this article, the basic techniques of blood pressure measurement and the technical issues associated with measurements in clinical practice are discussed. The devices currently available for hospital and clinic measurements and their important sources of error are presented. Practical advice is given on how the different devices and measurement techniques should be used. Blood pressure measurements in different circumstances and in special populations such as infants, children, pregnant women, elderly persons, and obese subjects are discussed.

Arterial stiffness correlated with cardiac remodelling in patients with chronic kidney disease

BACKGROUND

It is well known that both pressure and volume overloads contribute to left ventricular hypertrophy (LVH) and left ventricular dilatation in patients with chronic kidney disease (CKD). Few studies have evaluated the association between increased pulse wave velocity (PWV) and LVH in CKD patients not yet receiving dialysis. The purpose of this study was to assess the relationship between arterial stiffness and cardiac remodelling in patients with CKD, and to determine the independent factors associated with increased left ventricular mass index (LVMI) and left ventricular volume index (LVVI).

METHODS

This cross-sectional study included 96 patients with CKD. Echocardiography and measurement of arterial stiffness by PWV were performed. Clinical and echocardiographic parameters were compared and analysed.

RESULTS

Associated with the increase of PWV, there were significant trends for progressive increase in LVMI, LVH, LVVI, left ventricular dilatation and left atrium in CKD patients. Multivariate regression analysis revealed that decreased PWV, in addition to increased haemoglobin and the use of beta-blocker, was an independent determinant associated with decrease in LVMI and LVVI.

CONCLUSION

Our study demonstrated the progressive structural remodelling of left ventricle and left atrium in CKD patients associated with increased severity of arterial stiffness. PWV was an important determinant of LVMI and LVVI in CKD patients.

The effects of left ventricular hypertrophy on the respiratory changes in transmitral Doppler flow patterns of hypertension patients

BACKGROUND

Left ventricular early diastolic fillings can be reduced by inspiration. However, the effects of left ventricular hypertrophy on such changes have not been studied before. This study was undertaken to investigate whether respiratory changes in transmitral Doppler flow were affected by left ventricular hypertrophy in hypertension patients.

METHODS

Eighty-three patients (mean age 46 +/- 8 years, 49 males) with untreated essential hypertension were included in this study. Transmitral Doppler flow velocity was measured both at end-expiration and end-inspiration. Left ventricular mass was measured by M-mode echocardiography. We divided patients into two groups based on the presence of left ventricular hypertrophy or not.

RESULTS

Twenty-one patients were diagnosed to have left ventricular hypertrophy. In patients without left ventricular hypertrophy, the peak early filling velocity decreased significantly (from 74 +/- 15 to 71 +/- 18 cm s(-1), P = 0.003), the peak atrial velocity increased significantly (from 65 +/- 17 to 74 +/- 15 cm s(-1), P < 0.001) and the early filling to atrial velocity ratio decreased significantly (from 1.2 +/- 0.3 to 1.1 +/- 0.3, P < 0.001) from end-expiration to end-inspiration. In patients with left ventricular hypertrophy, the parameters of transmitral Doppler flow pattern did not change during respiration.

CONCLUSION

Respiratory changes in the transmitral Doppler flow velocity are blunted by left ventricular hypertrophy in hypertension patients. This phenomenon is probably contributed by the increased left ventricular wall stiffness in the left ventricular hypertrophy.

Principles and techniques of blood pressure measurement

The gold standard for clinical blood pressure measurement continues to be readings taken by a physician using a mercury sphygmomanometer, but this is changing as mercury is gradually being phased out. The oscillometric technique, which primarily detects mean arterial pressure, is increasingly popular for use in electronic devices. Other methods include ultrasound (used mainly to detect systolic pressure) and the finger cuff method of Penaz, which can record beat-to-beat pressure noninvasively from the finger. The preferred location of measurement is the upper arm, but errors may occur because of changes in the position of the arm. Other technical sources of error include inappropriate cuff size and too rapid deflation of the cuff. Clinic readings may be unrepresentative of the patient's true blood pressure because of the white coat effect, which is defined as the difference between the clinic readings and the average daytime blood pressure. Patients with elevated clinic pressure and normal daytime pressure are said to have white coat hypertension. There are three commonly used methods for measuring blood pressure for clinical purposes: clinic readings, self-monitoring by the patient at home, and 24-hour ambulatory readings. Self-monitoring is growing rapidly in popularity and is generally carried out using electronic devices that work on the oscillometric technique. Although standard validation protocols exist, many devices on the market have not been tested for accuracy. Such devices can record blood pressure from the upper arm, wrist, or finger, but the arm is preferred. Twenty-four-hour ambulatory monitoring has been found to be the best predictor of cardiovascular risk in the individual patient and is the only technique that can describe the diurnal rhythm of blood pressure accurately. Ambulatory monitoring is mainly used for diagnosing hypertension, whereas self-monitoring is used for following the response to treatment. Different techniques of blood pressure measurement may be preferred in certain situations. In infants the ultrasound technique is best, whereas in pregnancy and after exercise the diastolic pressure may be hard to measure using the conventional auscultatory method. In obese subjects it is important to use a cuff of the correct size.

Blood pressure reduction in the morning yields beneficial effects on progression of chronic renal insufficiency with regression of left ventricular hypertrophy

Self-monitoring values of blood pressure may better reflect the average long-term blood pressure value than sporadic measurements in the physician's office and be more useful for blood pressure control. In the present study, we compared the results of self-monitoring of blood pressure values, especially in the morning, with office blood pressure, and related these to progression of chronic renal insufficiency and left ventricular hypertrophy (LVH). Thirty-four patients were selected from 316 subjects with chronic renal insufficiency (average serum creatinine 1.72 +/- 0.15 mg/dl, mean age 52.6 +/- 3.5 yrs) in accordance with the following criteria (1) office blood pressure was less than 140/90 mmHg, (2) blood pressure was controlled with amlodipine (5-20 mg/day) combined with benazepril (2.5 mg/day), (3) morning blood pressure was greater than 150/90 mmHg at 6-9 AM and (4) LVH had been determined by echocardiography (posterior wall thickness; PWT > or = 12 mm). The patients were assigned to 2 groups at random and were given: (1) guanabenz (GB; 2-8 mg at I I PM, n = 17) or (2) placebo (n = 17). Two years later, the average blood pressure of both groups as measured in the office was not significantly different: however, BP in the morning was significantly reduced from 158 +/- 6 to 134 +/- 4 mmHg in GB treated group (P< 0.001). In 14 of 17 patients in GB treated group, LVH resolved and there was only mild progression of nephropathy (serum creatinine: 1.69 +/- 0.18 to 1.81 +/- 0.19 mg/dl). In 12 of 14 patients in placebo group, whose morning blood pressure remained at greater than 150/90 mmHg, LVH was retained and there was moderate progression of nephropathy (serum creatinine: 1.73 +/- 0.14 to 2.62 +/- 0.50mg/dl). From these results, it is suggested that antihypertensive treatment with combination therapy based on self-monitoring BP is cardio-renoprotective in patients with chronic renal insufficiency and LVH.