Maxime Lamarre-Cliche

The 2013 Canadian Hypertension Education Program recommendations for blood pressure measurement, diagnosis, assessment of risk, prevention, and treatment of hypertension.

We updated the evidence-based recommendations for the diagnosis, assessment, prevention, and treatment of hypertension in adults for 2013. This years update includes 2 new recommendations. First, among nonhypertensive or stage 1 hypertensive individuals, the use of resistance or weight training exercise does not adversely influence blood pressure (BP) (Grade D). Thus, such patients need not avoid this type of exercise for fear of increasing BP. Second, and separately, for very elderly patients with isolated systolic hypertension (age 80 years or older), the target for systolic BP should be < 150 mm Hg (Grade C) rather than < 140 mm Hg as recommended for younger patients. We also discuss 2 additional topics at length (the pharmacological treatment of mild hypertension and the possibility of a diastolic J curve in hypertensive patients with coronary artery disease). In light of several methodological limitations, a recent systematic review of 4 trials in patients with stage 1 uncomplicated hypertension did not lead to changes in management recommendations. In addition, because of a lack of prospective randomized data assessing diastolic BP thresholds in patients with coronary artery disease and hypertension, no recommendation to set a selective diastolic cut point for such patients could be affirmed. However, both of these issues will be examined on an ongoing basis, in particular as new evidence emerges.

The 2011 Canadian Hypertension Education Program Recommendations for the Management of Hypertension: Blood Pressure Measurement, Diagnosis, Assessment of Risk, and Therapy

We updated the evidence-based recommendations for the diagnosis, assessment, prevention, and treatment of hypertension in adults for 2011. The major guideline changes this year are: (1) a recommendation was made for using comparative risk analogies when communicating a patients cardiovascular risk; (2) diagnostic testing issues for renal artery stenosis were discussed; (3) recommendations were added for the management of hypertension during the acute phase of stroke; (4) people with hypertension and diabetes are now considered high risk for cardiovascular events if they have elevated urinary albumin excretion, overt kidney disease, cardiovascular disease, or the presence of other cardiovascular risk factors; (5) the combination of an angiotensin-converting enzyme (ACE) inhibitor and a dihydropyridine calcium channel blocker (CCB) is preferred over the combination of an ACE inhibitor and a thiazide diuretic in persons with diabetes and hypertension; and (6) a recommendation was made to coordinate with pharmacists to improve antihypertensive medication adherence. We also discussed the recent analyses that examined the association between angiotensin II receptor blockers (ARBs) and cancer.

A New Algorithm for the Diagnosis of Hypertension in Canada

Accurate blood pressure measurement is critical to properly identify and treat individuals with hypertension. In 2005, the Canadian Hypertension Education Program produced a revised algorithm to be used for the diagnosis of hypertension. Subsequent annual reviews of the literature have identified 2 major deficiencies in the current diagnostic process. First, auscultatory measurements performed in routine clinical settings have serious accuracy limitations that have not been overcome despite great efforts to educate health care professionals over several years. Thus, alternatives to auscultatory measurements should be used. Second, recent data indicate that patients with white coat hypertension must be identified earlier in the process and in a systematic manner rather than on an ad hoc or voluntary basis so they are not unnecessarily treated with antihypertensive medications. The economic and health consequences of white coat hypertension are reviewed. In this article evidence for a revised algorithm to diagnose hypertension is presented. Protocols for home blood pressure measurement and ambulatory blood pressure monitoring are reviewed. The role of automated office blood pressure measurement is updated. The revised algorithm strongly encourages the use of validated electronic digital oscillometric devices and recommends that out-of-office blood pressure measurements, ambulatory blood pressure monitoring (preferred), or home blood pressure measurement, should be performed to confirm the diagnosis of hypertension.

Effect of the renin-angiotensin system or calcium channel blockade on the circadian variation of heart rate variability, blood pressure and circulating catecholamines in hypertensive patients.

Objective To determine the effects of 8 weeks of therapy with amlodipine, ramipril or telmisartan on the autonomic system over 24 h in hypertensives. Methods After a placebo run-in, 57 patients were included in a prospective randomized open-label design protocol for therapy with amlodipine (5 mg for 4 weeks followed by 10 mg for 4 weeks, n = 22), or ramipril (2.5 mg for 1 week, 5.0 mg for 3 weeks and 10 mg for 4 weeks, n = 17) or telmisartan (80 mg for 8 weeks, n = 18). Autonomic functions were assessed by norepinephrine (NE) and epinephrine (E), as well as by the spectral analysis of heart rate variability (HRV). Results The 24-h ambulatory blood pressure, plasma NE and HRV demonstrated the characteristic day–night circadian rhythm in hypertensives. Higher values for SBP and DBP and for NE levels, as well as for spectral analysis components – low frequency band (LF) and low frequency/high frequency (LF/HF) ratio – were found during the day, whereas the HF was higher during the night. In patients treated with amlodipine, the HF decreased significantly during the night, while the LF and the LF/HF ratio increased during the day in association with the rise in NE. The therapy with telmisartan did increase the HF during the night and the day, while ramipril did not influence all HRV components during the night but significantly increased the HF, and decreased the LF/HF ratio during the day. No changes were observed in plasma NE with telmisartan or ramipril, but a 50% increase in NE levels throughout the 24-h period was found in amlodipine-treated patients. Conclusion These data suggest a sympathetic activation during the day and a decrease in parasympathetic activity during the night after therapy with amlodipine, correlated with increases in plasma NE. In contrast, the therapy with telmisartan significantly increased parasympathetic activity without changes in NE during the night and day. The therapy with ramipril increased the parasympathetic activity only during the day.

Integrating Drug Pharmacokinetics for Phenotyping Individual Renin Response to Angiotensin II Blockade in Humans

Abstract—Renin release into plasma has been used to investigate the drug dose-dependence of renin-angiotensin system inhibition because it is proportional to the interruption of the permanent negative feedback loop of angiotensin II on renin secretion. We investigated the 24-hour between-subject differences in renin profiles by analyzing the time-dependence of individual renin responses in 16 mildly sodium-depleted normotensive subjects exposed in a 4-period crossover study to single oral doses of 8- and 16-mg (C8 and C16) candesartan cilexetil and 80- and 160-mg (V80 and V160) valsartan. C8 had a similar effect to V160 in terms of the increase in active renin concentration and decrease in blood pressure. C16 had the strongest effect and V80 the weakest effect on renin release. Within- and between-subject variability was more marked for valsartan pharmacokinetics than for candesartan pharmacokinetics and influenced variability in renin response. To eliminate some of the variability caused by the pharmacokinetics of each drug, we corrected the area under time curve of plasma renin levels by that of plasma drug levels to obtain an individual normalized index of renin release or “renin/pharmacokinetic index”. In these experimental conditions, this index was found to be a reproducible individual characteristic affecting renin response, in addition to the pharmacokinetics and pharmacological properties of angiotensin II type-1 receptor antagonists. The pharmacokinetic–pharmacodynamic model of renin release described here could be of value for the identification and investigation of renin release abnormalities in patients with hypertension and for the comparison of renin-angiotensin system blockers.

Pharmacokinetic and Pharmacodynamic Effects of Midodrine on Blood Pressure, the Autonomic Nervous System, and Plasma Natriuretic Peptides: A Prospective, Randomized, Single-Blind, Two-Period, Crossover, Placebo-Controlled Study

BACKGROUND Midodrine is an alpha-agonist prodrug of desglymidodrine (DGM) that has been reported to be of clinical benefit in patients with neurocardiogenic syncope. Its effects may be mediated not only by its hypertensive properties but also by its neurohumoral influences independent of blood pressure (BP). OBJECTIVE The present study aimed to simultaneously characterize the effects of midodrine on BP, plasma catecholamines, plasma atrial natriuretic peptide (ANP), and power spectral analysis of heart rate (HR) in healthy volunteers. METHODS This was a prospective, randomized, single-blind, 2-period, crossover study in which a single, oral, 5-mg dose of midodrine was compared with placebo. The washout period between midodrine and placebo was 1 week. The study parameters included plasma DGM (as measured by high-performance liquid chromatography [HPLC]); systolic and diastolic BP (as measured with an oscillometric monitor); HR; plasma catecholamines (measured by HPLC); plasma ANP, also known as venous return (measured by a radio-immunoassay); and low- and high-frequency HR variation (calculated from computerized 5-minute electrocardiographic recordings). All study parameters were measured simultaneously 12 times just before and over a period of 8 hours after drug administration. RESULTS Fifteen healthy nonsmoking male subjects (14 white, 1 black; mean [SD] age, 28.6 [4.7] years; weight, 74.5 [16.4] kg; seated BP, 109.9 [9.0]/73.6 [9.5] mm Hg; seated HR, 63.8 [8.4] bpm) were randomized. No significant effects of midodrine on BP were observed. At Cmax, midodrine decreased norepinephrine from 188.4 (30.6) to 162.5 (29.8) pg/mL (P = 0.011) and HR from 57.2 (7.3) to 54.9 (6.6) bpm (P = 0.022). A significant correlation was found between DGM concentration and HR ( varphi -0.61; P = 0.014). A DGM-related increase in plasma ANP (+29.6 [90.0] fmoL/mL) was observed. CONCLUSION This study in healthy male volunteers found that midodrine has sympatholytic influences that are independent of BP but related to augmented venous return.

Impaired 11-β Hydroxysteroid Dehydrogenase Type 2 Activity in Sweat Gland Ducts in Human Essential Hypertension

Abstract—The enzyme 11-&bgr; hydroxysteroid dehydrogenase type 2 plays a major role in blood pressure regulation. It metabolizes glucocorticoid hormones into derivatives with low affinity for the mineralocorticoid receptor, preventing its permanent occupancy by circulating cortisol, which is 100- to 1000-fold more abundant than aldosterone in the plasma. Inactivating mutations of the enzyme result in severe hypertension, as seen in children with apparent mineralocorticoid excess syndrome. In patients with essential hypertension, however, attempts to evidence enzyme deficiency have been inconclusive. In this pilot study, its catalytic activity was measured directly in aldosterone-sensitive sweat gland ducts collected from skin biopsy samples of 10 male normotensive subjects and 10 subjects with essential hypertension (more than 140 to 90 mm Hg) with no sign of hypermineralocorticism. Isolated ducts were assayed for nicotinamide-dinucleotide-dependent dehydrogenase activity (transformation of tritiated corticosterone into tritiated-11 dehydrocorticosterone, as measured by high-pressure liquid chromatography). Hypertensive patients exhibited significantly lower 11-&bgr; hydroxysteroid dehydrogenase type 2 activity (9.7±4.7 femtomoles per 3 mm length of duct and per 10 minutes incubation, median±SD) than did normotensive subjects (15.9±2.6). Such defect was undetectable using the classical urinary corticosteroid metabolism indexes, probably because of compensatory mechanisms. Relations between these findings and blood pressure levels should benefit from direct enzyme measurements in the vasculature. In conclusion, this cross-sectional study points to partial 11-&bgr; hydroxysteroid dehydrogenase type 2 deficiency as a novel feature of essential hypertension, which should stimulate search for new signaling pathways and therapeutical targets.

Unreliability of Home Blood Pressure Measurement and the Effect of a Patient-Oriented Intervention

BACKGROUND Home blood pressure (BP) measurement (HBPM) is recommended for the diagnosis and follow-up of high BP. It is unclear how this aspect of BP monitoring has evolved over the years and whether interventions could influence patient adherence to HBPM guidelines. METHODS After a questionnaire-based cross-sectional study performed in 2010, a passive, multimodal intervention, focused on improving adherence to HBPM guidelines, was implemented. A second study was conducted in 2014 to measure its effect. RESULTS In 2010 and 2014, 1010 and 1005 patients, respectively, completed the questionnaire. In 2010 and 2014, 82% and 84% of patients, respectively, self-measured their BP. Reporting of HBPM and adherence to recommended procedures was suboptimal. Only 34.0% of patients in 2010 and 31.7% in 2014 brought > 80% of their measurements to their doctor. Only 49.6% in 2010 and 52.9% in 2014 prepared > 80% of the time for HBPM. Only 48.1% in 2010 and 52.1% in 2014 rested for 5 minutes > 80% of the time before HBPM. Only 15% of patients in 2010 and 18% in 2014 were defined as sufficiently compliant with all HBPM procedures. Paired analysis of a subset of 535 patients who participated in the 2010 and 2014 studies showed no clinically significant differences in reliability between the 2 surveys. CONCLUSIONS Adherence to HBPM guidelines was suboptimal in 2010 and still is in 2014 despite a passive, multimodal intervention. Active training in HBPM procedures should be studied. Greater automation could improve HBPM reliability.

Comparison of Different Automated Office Blood Pressure Measurement Devices: Evidence of Nonequivalence and Clinical Implications

BACKGROUND Automated office blood pressure (AOBP) measuring devices are increasingly recommended as preferred blood pressure (BP) diagnostic tools, but it is unclear how they compare and how clinical environments impact their performance. METHODS This prospective randomized factorial parallel 4-group study compared BP estimates by BpTRU (VSM MedTech, Vancouver, BC, Canada) and Omron HEM 907 (Omron Healthcare, Kyoto, Japan) devices in closed vs open areas. Patients diagnosed with hypertension were recruited during office visits. After baseline open-room AOBP measurement with the BpTRU, patients had a second BP measurement with either the BpTRU or HEM 907 in either open or closed areas. Absolute BP levels and differences between the first and second measurements were compared. Diagnostic performance was also assessed. RESULTS Two hundred fifty-eight patients were studied. Their mean age was 66.2 ± 12.0 years, and 62% were men. The mean of first AOBP estimates was 127.4/73.3 mm Hg. Analyses of subsequent measurements revealed no influence of open or closed areas on BP means and diagnostic performance. Conversely, the Omron HEM 907 exceeded BpTRU systolic BP measurements by 4.6 mm Hg (< 0.01) in closed areas and by 3.9 mm Hg (< 0.01) in open areas. The discrepancy between devices was amplified at lower BP levels. CONCLUSIONS Although different areas did not influence BP estimates, the Omron HEM 907 significantly exceeded BpTRU measurements on average and especially at lower BP levels. These differences should be considered when interchanging devices and could have clinical decision impacts in a population of patients treated for hypertension. Our results support the constant use of only 1 device type in a given clinic.

Lack of Clinical Benefit of Thromboprophylaxis in Patients Hospitalized in a Medical Unit Over a 10-year Span

Background Thromboprophylaxis for hospitalized patients with a high risk of venous thromboembolic events (VTEs) is strongly recommended but is not universally applied on medical units. Outside of randomized trials, there is minimal evidence that the usual medications reduce the incidence of clinically significant VTE. Methods We conducted a retrospective cohort study including all patients admitted into a teaching medical unit during years 2001-2002, 2003-2004, 2005-2006, 2007-2008 and 2009-2010. Inclusion criteria for the analysis were having one or more risk factors for a VTE and no contraindication to thromboprophylaxis. Results Of 2,369 patients reviewed, 1,302 satisfied the inclusion criteria. Between years 2001-2002 and 2009-2010, the proportion of patients receiving thromboprophylaxis increased from 29.2% to 76.4% (P < 0.0001) and the duration of thromboprophylaxis increased from 63% of hospital stay to 84% (P = 0.004). There was no statistically significant association between the number of risk factors and the rate of thromboprophylaxis. Overall, only 32 patients suffered from a VTE with no decrease in VTE incidence between years 2001-2002 and 2009-2010. A total of 107 patients had a bleeding event, and there was no statistically significant change in the incidence of bleeding during our study period. Conclusions In our medical units, we found a statistically significant increase in the use of the thromboprophylaxis practice. However, this was not associated with any statistically significant impact on the VTE incidence. This suggests that patients given thromboprophylaxis could be better selected.