K. Vemmos

Impact of the time rate of blood pressure variation on left ventricular mass

Objectives Blood pressure (BP) changes are steeper in hypertensive than in normotensive individuals, whereas an increased rate of BP fluctuations is associated with medial hypertrophy of the carotid arteries. We evaluated the association between the rate of BP variation derived from ambulatory blood pressure monitoring (ABPM) data analysis and left ventricular mass (LVM). Methods ABPM and echocardiographic measurements of LVM were performed in 365 normotensive, 185 white-coat hypertensive (WCH) and 448 uncomplicated hypertensive individuals. Results The daytime and night-time rate of systolic blood pressure (SBP) and diastolic BP variation were significantly higher in hypertensive than in normotensive (P < 0.001) and WCH (P < 0.05) individuals. In the entire study population multiple linear regression models revealed independent determinants of LVM in the following rank order: body mass index (β + 0.266, P < 0.001), daytime SBP (β + 0.264, P < 0.001), male sex (β +0.220, P < 0.001), age (β + 0.203, P < 0.001), daytime heart rate (HR; β − 0.191, P < 0.001), daytime rate of SBP variation (β + 0.167, P < 0.001), and SBP dipping (β − 0.132, P < 0.001). A 0.1 mmHg/min increase in the daytime rate of SBP variation correlated with an increment of 7.087 g (95% confidence interval 4.775–9.399) in the LVM. The addition of the daytime rate of SBP variation in the multiple regression model for the prediction of LVM significantly increased the adjusted model R2 [R2 change 0.024 (2.4%); P for change < 0.001]. Conclusion Steeper BP variations may produce a greater stress on the left ventricular wall and may have an additive role to body habitus, BP and HR levels in the detection of cardiac hypertrophy. Target-organ damage in hypertensive patients, in addition to BP levels, dipping status and BP variability, may also be related to a steeper rate of BP oscillations.

Reproducibility of ambulatory blood pressure measurements in essential hypertension.

Background Data on the reproducibility of serial measurements of ambulatory blood pressure in hypertensive patients are lacking. The purpose of this study was to examine (1) the reproducibility of four consecutive ambulatory blood pressure measurements, and (2) the reproducibility of nocturnal falls in blood pressure in hypertensive patients. Methods Twenty patients with mild to moderate essential hypertension underwent four separate ambulatory blood pressure monitorings, on the same day of the week, at 30‐day intervals. Antihypertensive therapy was discontinued for 2 weeks before each recording. Comparing the mean values of blood pressure over 24 h, as well as diurnal, nocturnal and hourly periods, among the four recordings determined the reproducibility of blood pressure measurements. A day/night difference in mean systolic and in mean diastolic blood pressure defined the nocturnal fall in blood pressure. Results No significant differences were observed in either hourly, 24‐h, diurnal or nocturnal systolic blood pressure, diastolic blood pressure and heart rate, or in the nocturnal fall in systolic and diastolic blood pressure among the four recordings. Conclusions Hourly systolic blood pressure, diastolic blood pressure, heart rate, and nocturnal fall in blood pressure were reproducible in four ambulatory blood pressure monitorings recorded over 4 months. These findings suggest that ambulatory blood pressure monitoring is a reliable tool to monitor blood pressure changes.

Hypothyroidism as a protective factor in acute stroke patients.

Objective  It has been reported that hypothyroidism is associated with better survival in elderly persons. We investigated possible associations of thyroid status with clinical outcome in patients with acute stroke.

White-coat effect in normotension and hypertension.

ObjectivesThe difference between clinic and daytime ambulatory blood pressure is referred to as the white-coat effect. In this study, we investigated (i) the magnitude of the white-coat effect in subjects with different daytime ambulatory blood pressure levels, and (ii) the association of the white-coat effect with left ventricular mass. MethodsA total of 1581 subjects underwent clinic blood pressure readings, 24-h ambulatory blood pressure monitoring and left ventricular echocardiographic assessment. Their mean daytime systolic blood pressure varied from 88.0 to 208.9 mmHg and their mean daytime diastolic blood pressure from 40.3 to 133.0 mmHg. ResultsA negative correlation was found between the systolic or diastolic white-coat effect and the systolic or diastolic daytime ambulatory blood pressure (r = −0.22, P < 0.000 and r = −0.50, P < 0.000, respectively). Left ventricular mass significantly correlated with ambulatory blood pressure (P < 0.001), but there was no association between left ventricular mass and clinic blood pressure or white-coat effect. Furthermore, the white-coat effect was reversed at the highest level of systolic or diastolic daytime ambulatory blood pressure (systolic over 170 mmHg or diastolic over 100 mmHg) when systolic or diastolic daytime ambulatory blood pressure was higher than systolic or diastolic clinic blood pressure (ambulatory blood pressure hypertension). ConclusionsThe white-coat effect shows an inverse association with daytime ambulatory blood pressure level (systolic or diastolic), being significantly more prominent for levels below 140/80 mmHg for systolic/diastolic daytime ambulatory blood pressure and reversed with daytime ambulatory blood pressure levels above 170/100 mmHg.

Susceptibility of the right and left canine atria to fibrillation in hyperglycemia and hypoglycemia

The objective of this study was to investigate the changes in the refractory period and in the susceptibility to fibrillation of canine atria associated with different levels of glycemia, and the differences in these parameters between the two atria. In 20 anesthetized, open-chest dogs weighing 24 kg, the effective refractory period was measured by atrial pacing with a run of 8 stimuli (S1-S1 350 ms) followed by a progressively earlier S2 until no stimulation of the atrial tissue occurred. The susceptibility to fibrillation was assessed by applying DC at 2, 3, and 4 V for 3 seconds, 7 times each, on the atrial appendage. If fibrillation occurred and persisted for 3 minutes, a transthoracic synchronized shock was delivered (200 J). The refractory period and the susceptibility to fibrillation were assessed under normoglycemia first, and then under hypo and hyperglycemia, in the right and left atrium successively, in random order. The incidence of induced atrial fibrillation in the right atrium was: hypoglycemia 31.96% (132 of 413 attempts); normoglycemia 24.11% (81 of 336; p < 0.05); and hyperglycemia 20.23% (85 of 420). Results for the left atrium were hypoglycemia 52.06% (215 of 413); normoglycemia 40.18% (135 of 336; p < 0.005); and hyperglycemia 32.86% (138 of 420; p < 0.05). Sustained atrial fibrillation (> 3 minutes) occurred significantly more often under hypo rather than hyperglycemia and stimulated the left rather than the right atrium. The refractory period was shortest under hypoglycemia in the left atrium and longest under normo or hyperglycemia in the right atrium.(ABSTRACT TRUNCATED AT 250 WORDS)

Ambulatory blood pressure monitoring in acute stroke: pathophysiology of the time rate of blood pressure variation and association with the 1-year outcome.

ObjectivesTime rate of blood pressure (BP) variation is a measure of the speed of BP fluctuations derived from a computerized analysis of ambulatory BP monitoring. The aim of this study was to identify pathophysiological differences in the time rate of BP variation between stroke subtypes, on the basis of the Trial of Org 10172 in Acute Stroke Treatment criteria, in the acute phase and to examine the impact of time rate of BP variation on outcome at 1 year after stroke. Patients and methodsA consecutive series of 109 first-ever stroke patients, who fulfilled our inclusion criteria, underwent 24 h ambulatory BP monitoring within 24 h after the onset of stroke. On the basis of the patients’ Modified Rankin Scale score at 1 year after stroke, the study population was divided into two groups: patients with a positive (n=73) and those with a negative outcome (n=36). ResultsThe 24-h rate of systolic BP variation is higher in patients with large artery atherosclerosis [0.692 mmHg/min; 95% confidence interval (CI) 0.627–0.757] compared with those with lacunar strokes (0.609 mmHg/min; 95% CI 0.579–0.640) or strokes of unknown etiology (0.586 mmHg/min; 95% CI 0.522–0.649). Moreover, patients with higher 24-h rates of systolic BP variation were more likely to have a negative outcome at 1 year (odds ratio 1.96; 95% CI 1.16–3.32). Moreover, each 0.1 mmHg/min increase in the 24-h rate of SBP variation was associated with a 1.96-fold increase in the odds of a negative outcome (95% CI 1.16–3.32). ConclusionTime rate of BP variation shows significant differences between stroke subtypes in the acute phase of the event, and it is associated with outcome at 1 year. Lowering the time rate of BP variation, in the acute phase, might lead to better outcomes in patients who have had a cerebrovascular incident.

Ambulatory blood pressure monitoring in acute stroke: the importance of time rate of blood pressure variation.

We read with great interest the work of Sico et al. [1]. The authors conclude that it is unlikely that guidelines will recommend the routine application of ambulatory blood pressure (ABP) monitoring among patients with stroke, until controlled trial data support interventions on the basis of the ABP data. The authors reviewed 23 articles fulfilling their inclusion criteria. So far, it is the largest and most complete systematic review of ABP monitoring in cerebrovascular diseases and, therefore, we congratulate the authors for undertaking this project.

[PP.17.07] DIFFERENCES IN BLOOD PRESSURE AND BLOOD PRESSURE VARIABILITY IN THE ACUTE PHASE OF LOBAR AND DEEP INTRACREBRAL HEMORRHAGE

Objective: Intracerebral hemorrhage (ICH) subtypes differ in underlying pathophysiology and outcome. Deep ICH is strongly associated with hypertension whereas lobar ICH in suspected to result mainly from cerebral amyloid angiopathy. However, little is known about acute blood pressure (BP) and blood pressure variability (BPV) in these different subtypes of ICH. Design and method: A total of 61 consecutive first-ever ICH patients registered in the Athens Stroke Registry underwent 24-hour ambulatory BP monitoring (ABPM) within 24 hours of haemorrhage onset. ICH was categorized based on topography, to deep and lobar. Stroke severity was measured using the National Institutes of Health Stroke Scale (NIHSS). Functional outcome was measured at 3 months using the modified Rankin Scale (mRS). BPV was defined as the standard deviation (SD) of blood pressure recordings made by ABPM. The Students t-test and the Chi-square test were used to compare between the two ICH subtypes; continuous variables were tested for normal distribution; p < or = 0.05 was used to indicate statistical significance. Results: The study population consisted of 45 deep and 16 lobar ICH. No differences were observed in age, gender, HASBLED score, and history of hypertension, diabetes mellitus, smoking, and alcohol consumption between the two groups. Comparisons regarding stroke severity (NIHSS) and functional outcome (mRS) revealed no significant difference (p = 0.82 and p = 0.59, respectively). The mean systolic BP 24 h was significantly higher in the deep ICH group compared to the lobar ICH group (165 ± 16 vs 155 ± 16 mmHg, p = 0.04). Mean diastolic BP 24 h was also higher in patients with deep haemorrhage compared to those with lobar ICH (97 ± 14 vs 89 ± 15 mmHg, p = 0.05). No significant differences were observed between the two groups for systolic or diastolic BPV (p = 0.62 and 0.9, respectively). Conclusions: Mean systolic and diastolic BP during the first 24 hours of ICH is higher in deep as compared to lobar haemorrhage. Further research is needed in order to explore the association between BP with outcome in different ICH subtypes.

[PP.17.14] ASSOCIATION BETWEEN BLOOD PRESSURE VARIABILITY AND FUNCTIONAL OUTCOME IN DIFFERENT ISCHEMIC STROKE SUBTYPES

Objective: Blood pressure variability (BPV) has been associated with worse outcomes after acute ischemic stroke (IS). The aim of this study was to investigate whether this association varies in the in different IS subtypes. Design and method: A total of 239 consecutive first-ever acute stroke patients registered in the Athens Stroke Registry underwent 24-hour ambulatory BP monitoring (ABPM) within 24 hours of stroke onset. Strokes were categorized according to the TOAST classification. Functional outcome was measured at 3 months using the modified Rankin Scale (mRS), and was dichotomised to either good (mRS < or = 2) or poor (mRS > 2). BPV was defined as the standard deviation (SD) of blood pressure recordings made by ABPM. Stroke severity was measured using the National Institutes of Health Stroke Scale (NIHSS). Logistic regression analysis was used to test whether systolic or diastolic BPV predicted functional outcome, after adjusting for age, stroke severity and history of hypertension, diabetes, hyperlipidaemia and smoking. Coefficients and 95% confidence interval (CI) were used to indicate effect size; p < or = 0.05 was used to indicate statistical significance. Results: IS was attributed to small vessel disease in 64 cases, to large artery atherosclerosis (LAA) in 54 cases and to cardioembolism in 77 cases. The remaining 44 cases were classified as cryptogenic stroke or of unknown origin. The mean age of the study population was 69.3 (10.1) and 64% were males. The median NIHSS at admission was 5 (0–33) and median mRS at 3 months was 2 (0–6). Mean SBP and DBP at admission were 161 (28) mmHg and 90 (12) mmHg, respectively. The logistic regression analysis revealed that higher diastolic BPV was independently associated with poor functional outcome at 3 months only in lacunar strokes (coefficient 0.30, CI 0.99–1.72, p = 0.05). No significant association was observed between BPV and functional outcome in IS caused by LAA (p = 0.38) or cardioembolism (p = 0.38). Conclusions: Increased diastolic BPV 24 hours after lacunar IS is associated with worse functional outcomes at 3 months. Further work is required to reproduce this finding in an independent cohort, and to explore possible underlying mechanisms.