Should β Blockers No Longer Be Considered First-line Therapy for the Treatment of Essential Hypertension Without Comorbidities?

Current and Emerging Classes of Pharmacological Agents for the Management of Hypertension

Cardiovascular disease accounts for more than 17 million deaths globally every year, of which complications of hypertension account for 9.4 million deaths worldwide. Early detection and management of hypertension can prevent costly interventions, including dialysis and cardiac surgery. Non-pharmacological approaches for managing hypertension commonly involve lifestyle modification, including exercise and dietary regulations such as reducing salt and fluid intake; however, a majority of patients will eventually require antihypertensive medications. In 2020, the International Society of Hypertension published worldwide guidelines in its efforts to reduce the global prevalence of raised blood pressure (BP) in adults aged 18 years or over. Currently, several classes of medications are used to control hypertension, either as mono- or combination therapy depending on the disease severity. These drug classes include those that target the renin-angiotensin-aldosterone system (RAAS) and adrenergic receptors, calcium channel blockers, diuretics and vasodilators. While some of these classes of medications have shown significant benefits in controlling BP and reducing cardiovascular mortality, the prevalence of hypertension remains high. Significant efforts have been made in developing new classes of drugs that lower BP; these medications exert their therapeutic benefits through different pathways and mechanism of actions. With several of these emerging classes in phase III clinical trials, it is hoped that the discovery of these novel therapeutic avenues will aid in reducing the global burden of hypertension.

Optimal Organ Protection and Blood Pressure Control with the Single Pill Combination Lisinopril, Amlodipine and Indapamide in Arterial Hypertension

Aim. To evaluate the single pill combination with lisinopril, amlodipine and indapamide ability in additional angioprotection achievement in patients with arterial hypertension and high pulse wave velocity (PWV) regardless on previous antihypertensive therapy (AHT).Material and methods. To the open non-randomized study duration 12 weeks 40 patients were included taking triple AHT during 6 months. All participants underwent ambulatory 24 hour blood pressure (BP) monitoring, applanation tonometry (augmentation index and central BP), pulse wave velocity assessment, laboratory tests (HbA1c, serum uric acid, high sensitive C-reactive protein [hsCRP], serum uric acid).Results. We observed additional systolic BP (SBP) and diastolic BP (DBP) reduction by 16.9% and 22.11% on lisinopril, amlodipine and indapamide single pill combination. Lisinopril, amlodipine and indapamide single pill combination decreased 24 h mean SBP by 16.77%, and 24 h mean DBP -23.5% (ABPM data), PWV by 19.7%, augmentation index by 14.81%, central SBP by 11.9% (p<0,05). There were positive changes in hsCRP level (-13.0%, p<0.05) and serum uric acid (-9.0%, p<0.05).Conclusion. Lisinopril, amlodipine and indapamide single pill combination provided control BP, arterial elastic properties improving (augmentation index, PWV, central BP) and favorable influence on inflammation and serum uric acid level.

Acute effects of device-guided slow breathing on sympathetic nerve activity and baroreflex sensitivity in posttraumatic stress disorder

Patients with posttraumatic stress disorder (PTSD) have elevated sympathetic nervous system reactivity and impaired sympathetic and cardiovagal baroreflex sensitivity (BRS). Device-guided slow breathing (DGB) has been shown to lower blood pressure (BP) and sympathetic activity in other patient populations. We hypothesized that DGB acutely lowers BP, heart rate (HR), and improves BRS in PTSD. In 23 prehypertensive veterans with PTSD, we measured continuous BP, ECG, and muscle sympathetic nerve activity (MSNA) at rest and during 15 min of DGB at 5 breaths/min ( n = 13) or identical sham device breathing at normal rates of 14 breaths/min (sham; n = 10). Sympathetic and cardiovagal BRS was quantified using pharmacological manipulation of BP via the modified Oxford technique at baseline and during the last 5 min of DGB or sham. There was a significant reduction in systolic BP (by -9 ± 2 mmHg, P < 0.001), diastolic BP (by -3 ± 1 mmHg, P = 0.019), mean arterial pressure (by -4 ± 1 mmHg, P = 0.002), and MSNA burst frequency (by -7.8 ± 2.1 bursts/min, P = 0.004) with DGB but no significant change in HR ( P > 0.05). Within the sham group, there was no significant change in diastolic BP, mean arterial pressure, HR, or MSNA burst frequency, but there was a small but significant decrease in systolic BP ( P = 0.034) and MSNA burst incidence ( P = 0.033). Sympathetic BRS increased significantly in the DGB group (-1.08 ± 0.25 to -2.29 ± 0.24 bursts·100 heart beats^-1·mmHg^-1, P = 0.014) but decreased in the sham group (-1.58 ± 0.34 to -0.82 ± 0.28 bursts·100 heart beats^-1·mmHg^-1, P = 0.025) (time × device, P = 0.001). There was no significant difference in the change in cardiovagal BRS between the groups (time × device, P = 0.496). DGB acutely lowers BP and MSNA and improves sympathetic but not cardiovagal BRS in prehypertensive veterans with PTSD. NEW & NOTEWORTHY Posttraumatic stress disorder is characterized by augmented sympathetic reactivity, impaired baroreflex sensitivity, and an increased risk for developing hypertension and cardiovascular disease. This is the first study to examine the potential beneficial effects of device-guided slow breathing on hemodynamics, sympathetic activity, and arterial baroreflex sensitivity in prehypertensive veterans with posttraumatic stress disorder.

Implication of different initial beta blockers on treatment persistence: atenolol vs new-generation beta blocker, a population-based study

AIM

Potential heterogeneity within the same class of drug in terms of persistence may lead to different clinical implications. Given that the increased risks of mortality and cardiovascular events are due, in part, to the lack of persistent use of antihypertensive medications, the objective of this study was to evaluate 1-year persistence of new-generation beta blockers compared to atenolol in antihypertensive treatment-naïve patients.

METHODS

A total of 9978 patients aged 18 years or older with hypertension newly diagnosed in 2012, without hypertension-related complication and initiated treatment with beta blocker monotherapy during 2012 were included in the analysis. Rate and duration of treatment and drug persistence were compared between atenolol and new-generation beta blockers. Hazards of discontinuation in nonatenolol compared to atenolol were evaluated using a multivariate Cox proportional model.

RESULTS

The rate of treatment persistence was higher in the nonatenolol group (57.35% vs 53.40%, P<.0001), and the time to treatment discontinuation was earlier in the atenolol group with a minimal difference in the average (243.2 vs 254 days, P<.0001). New-generation beta blockers demonstrated a lower risk of treatment discontinuation (HR: 0.91, 95% CI: 0.86-0.96) compared to atenolol; a notable improvement was observed with carvedilol and nebivolol (HR: 0.74, 95% CI: 0.69-0.80 and HR: 0.79, 95% CI: 0.70-0.89, respectively), whereas betaxolol showed a substantially greater hazard for discontinuation compared to atenolol.

CONCLUSIONS

This study demonstrated a meaningful improvement in treatment persistence with new-generation beta blockers compared to atenolol, with betaxolol as exception.

Kidney function and population-based outcomes of initiating oral atenolol versus metoprolol tartrate in older adults

BACKGROUND

Atenolol and metoprolol tartrate are commonly prescribed β-blockers. Atenolol elimination depends on kidney function, whereas metoprolol tartrate does not. We hypothesized that compared to metoprolol tartrate, initiating oral atenolol treatment would be associated with more adverse events in older adults, with the association most pronounced in patients with lower baseline estimated glomerular filtration rates (eGFRs).

STUDY DESIGN

Population-based matched retrospective cohort study.

SETTING & PARTICIPANTS

Older adults (mean age, 75 years) in Ontario, Canada, prescribed oral atenolol versus metoprolol tartrate from April 2002 through December 2011. The 2 groups were well matched (n=75,257 in each group), with no difference in 31 measured baseline characteristics. Patients with end-stage renal disease were ineligible, and 4.6% of patients had chronic kidney disease (median eGFR, 38mL/min/1.73m(2) assessed through a database algorithm).

PREDICTORS

β-Blocker type and eGFR.

OUTCOMES

A composite outcome of hospitalization with bradycardia or hypotension and all-cause mortality were assessed in 90-day follow-up.

RESULTS

Compared to metoprolol tartrate, initiating atenolol treatment was not associated with higher risk of hospitalization with bradycardia or hypotension (incidence, 0.71% vs 0.79%; relative risk, 0.90; 95%CI, 0.80-1.01). Atenolol treatment initiation was associated with lower 90-day risk of mortality than metoprolol tartrate (incidence, 0.97% vs 1.44%; relative risk, 0.68; 95%CI, 0.61-0.74). Lower eGFR did not modify either association (P for interaction=0.5 and 0.6, respectively).

LIMITATIONS

Heart rate and blood pressure were not available in our data sources, and effects ascertained from observational studies are subject to residual confounding.

CONCLUSIONS

Contrary to our expectation, we found that atenolol versus metoprolol tartrate was associated with lower 90-day risk of mortality in patients regardless of eGFR, with no difference in risk of hospitalization with bradycardia or hypotension.

Central blood pressure: current evidence and clinical importance

Pressure measured with a cuff and sphygmomanometer in the brachial artery is accepted as an important predictor of future cardiovascular risk. However, systolic pressure varies throughout the arterial tree, such that aortic (central) systolic pressure is actually lower than corresponding brachial values, although this difference is highly variable between individuals. Emerging evidence now suggests that central pressure is better related to future cardiovascular events than is brachial pressure. Moreover, anti-hypertensive drugs can exert differential effects on brachial and central pressure. Therefore, basing treatment decisions on central, rather than brachial pressure, is likely to have important implications for the future diagnosis and management of hypertension. Such a paradigm shift will, however, require further, direct evidence that selectively targeting central pressure, brings added benefit, over and above that already provided by brachial artery pressure.

β-Blockers

Objective: To review the pharmacology, pharmacokinetics, and pharmacodynamic properties of commonly used β-blockers (atenolol, carvedilol, metoprolol succinate, metoprolol tartrate, and nebivolol). Data Sources: A MEDLINE literature search (1966-May 2013) was performed using the following key terms: hypertension, β-blockers, atenolol, carvedilol, metoprolol tartrate, metoprolol succinate, nebivolol, pharmacology, pharmacodynamics, pharmacokinetics, blood pressure, metabolic, lipid, central aortic pressure, diabetes, and insulin resistance. References from publications reviewed were included. Study Selection and Data Extraction: English-language articles identified were reviewed. Animal studies and studies in patients for a primary diagnosis of coronary artery disease were excluded. Data Synthesis: β-Blockers are no longer recommended first-line therapy for primary hypertension, based on data showing that β-blockers are inferior to other antihypertensives and no better than placebo, in spite of provision of blood pressure reduction. Because atenolol is the β-blocker used in 75% of these studies, uncertainty about widespread application to all β-blockers exists. Different pharmacological and physiological properties, both within β-blockers and compared with other antihypertensives, may explain divergent effects. Evidence shows that β-blockers have a truncated effect on central aortic pressure, an independent predictor of cardiovascular events, compared with other antihypertensive classes; differences within the class may exist, but the evidence is inconclusive. Metabolic effects differ within the β-blocker class, with evidence that carvedilol causes less metabolic dysregulation. Conclusion: Emerging evidence reveals physiological differences within the β-blocker class and in comparison to other antihypertensives. These differences provide insight into the diverse clinical effects β-blockers provide in cardiovascular disease.

Beta-Blockers in the Management of Hypertension and/or Chronic Kidney Disease

This minireview provides current summaries of beta-blocker use in the management of hypertension and/or chronic kidney disease. Accumulated evidence suggests that atenolol is not sufficiently effective as a primary tool to treat hypertension. The less-than-adequate effect of beta-blockers in lowering the blood pressure and on vascular protection, and the unfavorable effects of these drugs, as compared to other antihypertensive agents, on the metabolic profile have been pointed out. On the other hand, in patients with chronic kidney disease, renin-angiotensin system blockers are the drugs of first choice for achieving the goal of renal protection. Recent studies have reported that vasodilatory beta-blockers have adequate antihypertensive efficacy and less harmful effects on the metabolic profile, and also exert beneficial effects on endothelial function and renal protection. However, there is still not sufficient evidence on the beneficial effects of the new beta-blockers.

Impact of heart rate on central hemodynamics and stroke: a meta-analysis of β-blocker trials

BACKGROUND

In a meta-analysis, we investigated effects of β-blockers on central hemodynamic measurements and explored the impact of heart rate (HR) on central hemodynamics and the risk of stroke.

METHODS

We searched randomized controlled trials that compared β-blockers with other classes of antihypertensive drugs in reducing central systolic blood pressure (cSBP) and augmentation index (cAI) and in preventing stroke. A random-effects model was used to compute pooled estimates.

RESULTS

In 9 trials (n = 754), β-blockers were less efficacious in reducing cAI than all the other classes of drugs (8.6%, P < 0.001). β-blockers were also less efficacious in reducing cSBP than angiotensin converting enzyme inhibitors (7.7 mm Hg, P = 0.02) and angiotensin receptor blockers (3.6 mm Hg, P = 0.005) but not the other classes of drugs (P ≥ 0.50). In a meta-regression analysis of these 9 trials, the baseline-adjusted difference in HR between randomized groups was associated with cAI (7.0% increase for each 10 bpm decrease in HR, P = 0.02), which was associated with cSBP (1.2 mm Hg increase for each 1% increase in cAI, P = 0.009). In 5 outcome trials, the pooled OR of stroke was 1.23 (P < 0.001), which would be accounted for by the difference in cSBP derived from the above meta-regression analysis.

CONCLUSIONS

Slowing HR with β-blockers may increase cAI and in turn may decrease cSBP less than with other classes of drugs. This mechanism might account for a smaller reduction in the risk of stroke when using β-blockers to treat hypertension.

Central hemodynamics in prehypertension: effect of the β-adrenergic antagonist nebivolol

The aim of the current study was to characterize the effects of the novel β-adrenergic antagonist nebivolol on central aortic blood pressures, arterial properties, and nitroxidergic activity in individuals with prehypertension. Prehypertension is emerging as a major risk factor for several adverse cardiovascular consequences. Increased pulse wave velocity, aortic augmentation index, and aortic blood pressures have been linked with augmented risk of cardiovascular disease and mortality. While the effects of antihypertensive drugs on these parameters in hypertensive patients have been studied, there are limited data so far in prehypertension. Fifty individuals with prehypertension were randomized to either nebivolol (5 mg per day) or placebo in a double-blind clinical trial. Patients underwent measurement of pulse wave velocity as well as aortic blood pressure and aortic augmentation index via pulse wave analysis at baseline and 8 weeks. Patients also had blood and urine biochemistries done at each visit. Nebivolol achieved significant reductions in central aortic systolic (P=.011), diastolic (P=.009), and mean arterial blood pressure (P=.002). Pulse wave velocity trended toward improvement but did not achieve significance (P=.088). Nitric oxide production, measured as urinary nitrite/nitrite excretion, also rose substantially in the nebivolol group (by approximately 60%, P=.030). Central blood pressures can be effectively lowered by β-blockade while patients are still in the prehypertension phase, and the effects may be coupled to improve nitric oxide release by the drug.