Echocardiographic and ultrasonographic evaluation of cardiac and vascular hypertrophy in patients with essential hypertension

Carotid intima-media thickness measurements in intervention studies: design options, progression rates, and sample size considerations: a point of view

BACKGROUND

Carotid intima-media thickness (CIMT) measurements are currently widely used in randomized controlled trials (RCTs) to study the efficacy of interventions. In designing a RCT with CIMT as a primary outcome, several ultrasound options may be considered. We discuss the various options and provide a pooled estimate of CIMT progression. In addition, we quantify the effect of these choices on the sample size for a RCT.

SUMMARY OF COMMENT

To estimate the average CIMT progression rate, we performed a pooled analysis using CIMT progression rates of control groups from published RCTs. The pros and cons of the following ultrasound options are discussed: which arterial segments may be studied; whether near and far wall CIMT measurements should be performed; whether a single image (1 angle of interrogation) or multiple images (more angles of interrogation) should be used; whether a manual or an automated edge detection reading system should be used; and whether images should be read in a random fashion or in batches. The pooled analysis showed an annual rate of change in mean common CIMT of 0.0147 mm (95% CI, 0.0122 to 0.0173) and in mean maximum CIMT of 0.0176 mm (95% CI, 0.0149 to 0.0203).

CONCLUSIONS

Given the current evidence together with our experience with recently developed ultrasound protocols, we favor the use of mean maximum CIMT rather than mean common CIMT as the primary outcome measure in RCTs designed to evaluate the efficacy of pharmacological and nonpharmacological interventions in carotid artery atherosclerosis.

Reduced nocturnal fall in blood pressure, assessed by two ambulatory blood pressure monitorings and cardiac alterations in early phases of untreated essential hypertension

To investigate whether in recently diagnosed essential hypertensives a reduced nocturnal fall in blood pressure (BP), established on the basis of two 24-h ambulatory blood pressure monitorings (ABPM) is related to a greater cardiovascular damage. In all, 355 consecutive, recently diagnosed, never-treated essential hypertensives referred for the first time to our outpatient clinic were included in the study. Each patient underwent the following procedures: (1) two 24-h ABPMs performed within 3 weeks, (2) 24-h urinary collection for microalbuminuria, (3) nonmydriatic photography of ocular fundi, (4) echocardiography, (5) carotid ultrasonography. We defined nondipping profile as a night-day systolic and diastolic fall < or =10 % (mean of two ABPMs). A dipper BP profile was found in 238 patients, whereas in 117 patients a nondipper profile was present. The two groups were similar for age, gender, body mass index, smoking habit, clinic BP, 48-h BP and heart rate, while, by definition, night-time systolic and diastolic BP were significantly higher in nondippers than in dippers (130/81 vs 121/74 mmHg, P < 0.0001).The prevalence of left ventricular hypertrophy (LVH) defined by four different criteria: (a) LV mass index (LVMI) > or = 125 g/m(2) in both genders; (b) LVMI > or = 134 gm(2) in men and > or = 110 in women; (c) LVMI> or = 125 g/m(2) in men and > or = 110 g/m(2) in women; (d) LVMI > or = 51 g/m(2.7) in men and > or = 47 g/m(2.7) in women was significantly higher in nondippers than in dippers (a: 12 vs 7%, P < 0.05; b: 16 vs 7%, P < 0.01; c: 20 vs 11%, P < 0.01; d: 35 vs 23% P < 0.02) and this finding was associated with a significant increase in aortic root and left atrium dimensions. There were no differences between the two groups in the prevalence of carotid and retinal changes and microalbuminuria. In conclusion our findings suggest that never-treated hypertensives with a reduced BP fall in the night time, defined on the basis of two ABPMs, have a higher prevalence of TOD than dippers, in terms of echocardiographic LVH. In this population setting, cardiac structural alterations are a more sensitive marker of the impact of the nocturnal BP load on cardiovascular system than other extracardiac signs of TOD.

Left ventricular concentric remodelling and extracardiac target organ damage in essential hypertension

Left ventricular (LV) concentric remodelling is an adaptive change in cardiac geometry frequently observed in arterial hypertension. This study was addressed to investigate the extent of extracardiac target organ damage (TOD) in patients with LV concentric remodelling. Two groups of never-treated essential hypertensives, 31 with normal LV geometry (group I, relative wall thickness: 0.39) and 31 with LV concentric remodelling (group II, relative wall thickness: 0.47) matched for age, sex, body mass index and mean 24-h systolic blood pressure (BP), were included in the study. They underwent clinical and laboratory examination, 24-h ambulatory BP monitoring (ABPM), 24-h urinary collection for microalbuminuria, non-mydriatic photography of ocular fundi, echocardiography and carotid ultrasonography. In both groups age (I: 51 +/- 11 years; II: 51 +/- 11 years), body mass index (I: 25 +/- 3 kg/m(2); II: 26 +/- 3 kg/m(2)), clinic and 24-h ABPM values (I: 149 +/- 11/95 +/- 8, 142 +/- 11/91 +/- 7 mm Hg; II: 150 +/- 11/98 +/- 9, 142 +/- 12/92 +/- 9 mm Hg) were similar by design. There were no differences between patients with normal LV geometry and with LV concentric remodelling in LVM index (97 +/- 16 vs 99 +/- 16), carotid intima-media thickness (0.7 +/- 0.02 vs 0.7 +/- 0.02) and carotid plaques prevalence (35% vs 35%). Furthermore, no significant differences among the two groups were found in the prevalence of retinal changes and microalbuminuria. These results suggest that in hypertensive patients with similar BP and LVMI levels, LV concentric remodelling is not associated with more prominent TOD.

High prevalence of cardiac and extracardiac target organ damage in refractory hypertension

OBJECTIVE

Target organ damage (TOD) in chronically treated hypertensives is related to effective blood pressure (BP) control. The aim of this study was to evaluate the prevalence of cardiac and extracardiac TOD in patients with refractory hypertension (RH) compared with well-controlled treated hypertensives (C).

METHODS

Fifty-four consecutive patients with RH (57 +/- 10 years), selected according to WHO/ISH guidelines definition, and 51 essential hypertensives (55 +/- 10 years) with satisfactory BP control obtained by association therapy, underwent the following procedures: (1) clinic BP measurement; (2) blood sampling for routine chemistry examinations; (3) 24 h urine collection for microalbuminuria; (4) non-mydriatic retinography; (5) echocardiogram; (6) carotid ultrasonogram. In order to exclude 'office resistance' (defined as clinic BP > 140/90 mmHg and average 24 h BP </= 125/79 mmHg), all patients with RH were subjected to 24-hour ambulatory BP monitoring.

RESULTS

Both groups were similar for age, gender, body surface area, smoking habit and duration of hypertension, glucose, creatinine and lipid levels. By definition, clinic BP was significantly higher in RH than C (161 +/- 19/96 +/- 9 versus 127 +/- 6/80 +/- 5 mmHg, respectively, P < 0.01). The increased prevalence of left ventricular hypertrophy (LVH) and carotid intima-media (IM) thickening (40 versus 12%, P < 0.01, according to a non-gender-specific partition value of 125 g/m2; and 36 versus 14%, P < 0.01, according to IM thickness > or =1.0 mm, respectively); a higher prevalence of carotid plaques (65 versus 32%, P < 0.05), a more advanced retinal involvement (grade II and III, 73 and 5% versus 38 and 0%, P < 0.01) and a greater albumin urinary excretion (22 +/- 32 mg/24 h versus 11 +/- 13 mg/24 h, P < 0.01) were found in RH compared to C.

CONCLUSIONS

Our study suggests that RH is a clinical condition associated with a high prevalence of TOD at cardiac, macro- and microvascular level and consequently with high absolute cardiovascular risk, which needs a particularly intensive therapeutic approach aimed to normalize BP levels and to induce TOD regression.

Target organ damage and non-dipping pattern defined by two sessions of ambulatory blood pressure monitoring in recently diagnosed essential hypertensive patients

OBJECTIVE

To evaluate in a selected population of patients with a recent diagnosis of hypertension whether a reduced nocturnal fall in blood pressure, confirmed by two 24 h ambulatory blood pressure monitoring (ABPM) sessions is associated with more prominent target organ damage (TOD).

METHODS

The study was structured in two phases: in the first, 141 consecutive, recently diagnosed, never-treated essential hypertensives underwent 24 h ABPM twice within 3 weeks; in the second phase, 118 of these patients showing reproducible dipping or non-dipping patterns underwent the following procedures: (1) routine blood chemistry, (2) 24 h urinary collection for microalbuminuria, (3) amydriatic photography of ocular fundi, (4) echocardiography and (5) carotid ultrasonography.

RESULTS

The 92 patients with (>10%) night-time fall in systolic blood pressure (SBP) and diastolic blood pressure (DBP) (dippers) in both monitoring sessions were similar for age, gender, body surface area, smoking habit, clinic BP, 24 h and 48 h BP to the 26 patients with a < or = 10% nocturnal fall (non-dippers) in both sessions. The prevalence of left ventricular hypertrophy (LVH) (defined by two criteria: (1) LV mass index > or = 125 g/m2 in both genders; (2) LV mass index > or = 120 and 100 g/m2 in men and women, respectively) and that of carotid intima-media (IM) thickening (IM thickness > or = 0.8 mm) were significantly higher in non-dippers than in dippers (23 versus 5%, P < 0.01; 50 versus 22%, P < 0.05; and 38 versus 18%, P < 0.05, respectively). There were no differences among the two groups in the prevalence of retinal changes and microalbuminuria. The strength of the association of LV mass index with night-time BP was slightly but significantly greater than that with daytime BP.

CONCLUSIONS

This study suggests that a blunted reduction in nocturnal BP, persisting over time, may play a pivotal role in the development of some expressions of TOD, such as LVH and IM thickening, during the early phase of essential hypertension, despite similar clinic BP, 24 h and 48 h BP levels observed in non-dippers and dippers.

Cardiovascular risk stratification in hypertensive patients: impact of echocardiography and carotid ultrasonography

BACKGROUND

Decision about the management of hypertensive patients should not be based on the level of blood pressure alone, but also on the presence of other risk factors, target organ damage (TOD) and cardiovascular and renal disease.

OBJECTIVE

To evaluate the impact of echocardiography and carotid ultrasonography in a more precise stratification of absolute cardiovascular risk.

METHODS

Never-treated essential hypertensives (n = 141; 73 men, 68 women, mean age 46 +/- 11 years) referred for the first time to our out-patient clinic were included in the study. They underwent the following procedures: (1) family and personal medical history, (2) clinical blood pressure (BP) measurement, (3) routine blood chemistry and urine analysis, (4) electrocardiogram, (5) echocardiogram, (6) carotid ultrasonogram. Risk was stratified according to the criteria suggested by the 1999 WHO/ISH guidelines. TOD was initially evaluated by routine procedures only, and subsequently reassessed by using data on cardiac and vascular structure obtained by ultrasound examinations (left ventricular hypertrophy (LVH) as left ventricular mass index (LVMI) > 134 g/m2 in men and > 110 g/m2 in women; carotid plaque as focal thickening > 1.3 mm).

RESULTS

According to the first classification 20% were low-risk patients, 50% medium-risk, 22% high-risk and 8% very-high-risk patients. A marked change in risk stratification was obtained when TOD was assessed by adding ultrasound examinations: low-risk patients 18%, medium-risk 28%, high-risk 45%, very-high-risk patients 9%.

CONCLUSIONS

The detection of TOD by ultrasound techniques allowed a much more accurate identification of high-risk patients, who represented a very large fraction (45%) of the patient population seen at our hypertension clinic. In particular, a large proportion of patients classified as at moderate risk by routine investigations were instead found to be at high risk when ultrasound examinations were added. The results of this study suggest that cardiovascular risk stratification only based on simple routine work-up can often underestimate overall risk, thus leading to a potentially inadequate therapeutic management especially of low-medium risk patients.

Impact of nocturnal fall in blood pressure on early cardiovascular changes in essential hypertension

OBJECTIVE

To evaluate in a selected population of subjects with a recent diagnosis of hypertension whether a blunted nocturnal fall in blood pressure is associated with more advanced cardiac and vascular damage.

METHODS

One hundred and eleven recently diagnosed and never-treated patients with mild essential hypertension underwent 24-h ambulatory blood pressure monitoring (ABPM), echocardiography and carotid ultrasonography.

RESULTS

The 78 patients with normal (> 10%) night-time fall in systolic blood pressure (SBP) and diastolic blood pressure (DBP) (dippers) were similar to the 33 patients with a small (< or = 10 %) fall (non-dippers) for age, sex, body surface area, smoking habit, clinic and 24-h blood pressure. There were no differences between dippers and non-dippers in left ventricular mass index (104 versus 105 g/m2), common carotid internal diameter (5.8 versus 5.9 mm), intima-media thickness (0.66 versus 0.64 mm) and carotid plaques prevalence (25 versus 29%). Furthermore, no differences were found in the correlation of daytime and night-time SBP and DBP with left ventricular mass and carotid wall thickness. When the 77 men and 34 women were analysed separately, similar results were obtained.

CONCLUSION

These results suggest that a blunted reduction in night-time blood pressure does not play a major role in the development of cardiovascular changes during the early phase of essential hypertension.

Intima-media thickness of the carotid artery in hypertensive subjects and hypertrophic cardiomyopathy patients

While hypertension is known to cause left ventricular and vascular hypertrophy, the relationship between alterations of vascular and cardiac structures in patients with hypertrophic cardiomyopathy has not been fully clarified. We measured intima-media thickness of carotid arteries by ultrasonography in patients with hypertrophic cardiomyopathy (n = 16), normotensive subjects (n = 358), and hypertensive subjects (n = 386) in a cohort of 7940 male employees of a bus company. Our object was to determine whether vascular alteration occurs in hypertrophic cardiomyopathy similarly as in hypertension. Hypertrophic cardiomyopathy (wall thickness > or = 15 mm; asymmetrical hypertrophy without hypertension) was screened with family history and electrocardiography followed by echocardiography. The intima-media thickness in patients with hypertrophic cardiomyopathy (mean, 0.61 mm) did not differ from that of normotensive subjects (0.60 mm) but was significantly less than that of hypertensive subjects with left ventricular hypertrophy (wall thickness > or = 14 mm; n = 22; 0.73 mm). In a scatterplot of intima-media thickness versus interventricular septal thickness, these two parameters were significantly correlated in normotensives and hypertensives. The patients with hypertrophic cardiomyopathy distributed outside the 95% confidence range of the normotensive and hypertensive subjects. In summary, the increase in intima-media thickness of the carotid artery paralleled left ventricular hypertrophy in normotensive and hypertensive subjects. Patients with hypertrophic cardiomyopathy had a normal intima-media thickness regardless of the hypertrophied left ventricle. Thus, information on intima-media thickness may be useful in differentiating hypertensive left ventricular hypertrophy from hypertrophic cardiomyopathy.