The role of Beta-blockers as first-line therapy in hypertension

Too much of a good thing: a case report of traumatic drop attacks and syncope due to orthostatic hypertension

Background

Orthostatic hypertension (OHT) is the clinical opposite to orthostatic hypotension and is an under-recognized and poorly understood clinical phenomenon. Patients may experience disabling symptoms such as dizziness, chest pain, and shortness of breath. In addition, OHT is associated with important clinical outcomes such as silent cerebral infarcts and cognitive decline.

Case summary

We present the case of a 67-year-old female who experienced frequent drop attacks with and without transient loss of consciousness causing various injuries. A range of standard diagnostic procedures did not yield an explanation for her symptoms but head-up tilt (HUT) testing showed OHT and induced most of her symptoms. Upon initiation of doxazosin, an alpha-blocking drug, she was free of symptoms and blood pressure response was normal on the repeat HUT test.

Discussion

To our knowledge, this is the first report of syncope due to OHT. Orthostatic hypertension is a heterogeneous condition and may occur in young, otherwise healthy individuals but also in older patients with cardiovascular comorbidities. It is thought that symptoms occur because of excessive venous pooling (causing a drop in cardiac output) or adrenergic hypersensitivity (resulting in cerebral vasoconstriction or acute rise in cardiac afterload). Since our patient had a marked response to an alpha-blocking agent, we think baroreflex hypersensitivity is the most likely cause of her complaints. Though syncope is probably rare, OHT should be regarded as a possible explanation of orthostatic symptoms.

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.

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.

The decline effect in cardiovascular medicine: is the effect of cardiovascular medicine and stent on cardiovascular events decline over the years?

The term decline effect is referred to a diminution of scientifically discovered effects over time. Reasons for the decline effect are multifaceted and include publication bias, selective reporting, outcomes reporting bias, regression to the mean, scientific paradigm shift, overshadowing and habituation, among others. Such effects can be found in cardiovascular medicines through medications (e.g., aspirin, antithrombotics, proton pump inhibitor, beta-blockers, statins, estrogen/progestin, angiotensin converting enzyme inhibitor etc.), as well as with interventional devices (e.g., angioplasty, percutaneous coronary intervention, stents). The scientific community should understand the various dimensions of the decline effects, and effective steps should be undertaken to prevent or recognize such decline effects in cardiovascular medicines.

Characteristics, drug combinations and dosages of primary care patients with uncontrolled ambulatory blood pressure and high medication adherence

Most studies on the prevalence and determinants of resistant hypertension (RH) do not account for white coat hypertension, medication non-adherence, or use of suboptimal treatment dosages. We studied the characteristics, drug combinations, and dosages of patients on at least three antihypertensives of different classes who had uncontrolled blood pressure on 24-hour ambulatory blood pressure monitoring and high medication adherence measured by electronic monitoring. The data were collected as part of the baseline measures of a hypertension control trial. Of 140 monitored primary care patients, all with uncontrolled office blood pressure, 69 (49%) were on at least three antihypertensives of different classes. Of these 69, 15 (22%) were controlled on ambulatory blood pressure monitoring, 20 (29%) were uncontrolled and non-adherent, leaving only 34 (49%) adherent to their medications and having uncontrolled ambulatory hypertension (uncontrolled RH). Thirty-one (91%) of the 34 uncontrolled RH patients were prescribed a diuretic, of which 24 were on hydrochlorothiazide 25 mg. Less than half of the patients on angiotensin-converting enzyme inhibitor, angiotensin receptor blocker, or calcium channel blocker were prescribed maximal doses of these agents. Half of the RH can be attributed to white coat effect and poor medication adherence, and all of the remaining patients were on apparently suboptimal drug combinations and/or dosages. Primary care physicians need to be educated regarding the optimal treatment of RH.

Epidemiology, pathophysiology, and treatment of hypertension in ischaemic stroke patients

Stroke continues to be one of the leading causes of mortality and morbidity worldwide. There are 2 main types of stroke: ischaemic strokes, which are caused by obstruction of the blood vessels leading to or within the brain, and haemorrhagic strokes, which are induced by the disruption of blood vessels. Stroke is a disease of multifactorial aetiology that may develop as an end state in patients with serious vascular conditions--most notably, uncontrolled arterial hypertension--thereby necessitating the effective control of this risk factor to prevent stroke or its recurrence. This paper focuses specifically on the epidemiology and pathogenesis of ischaemic stroke mainly in chronically hypertensive patients and pays particular attention to the efficacy of a select group of routinely used major antihypertensive drugs (i.e., angiotensin-converting enzyme inhibitors, angiotensin II type 1 receptor blockers, and calcium channel blockers) in the treatment of strokes.

New insights into hypertension-associated erectile dysfunction

PURPOSE OF REVIEW

Erectile dysfunction is recognized as a quality-of-life disorder that needs to be treated. Currently, it is estimated to affect as many as 30 million American men. Thirty percent of hypertensive patients complain of erectile dysfunction. The understanding of common mechanisms involved in the cause of erectile dysfunction associated with hypertension, and the investigation of antihypertensive drugs that impact erectile dysfunction, will provide important tools toward identifying new therapeutic targets that will improve the quality of life for patients in these conditions.

RECENT FINDINGS

Hypertension and erectile dysfunction are closely intertwined diseases, which have endothelial dysfunction as a common base. During hypertension and/or erectile dysfunction, disturbance of endothelium-derived factors can lead to an increase in vascular smooth muscle (VSM) contraction. Hypertension can lead to erectile dysfunction as a consequence of high blood pressure (BP) or due to antihypertensive treatment. However, growing evidence suggests erectile dysfunction is an early sign for hypertension. Also, some phosphodiesterase-5 inhibitors used to treat erectile dysfunction can improve BP, but the link between these conditions has not been totally understood.

SUMMARY

This review will discuss the interplay between hypertension and erectile dysfunction, exploring newest insights regarding hypertension-associated erectile dysfunction, as well as the effect of antihypertensive drugs in erectile dysfunction patients.

Use of carvedilol in hypertension: an update

β-blockers are effective antihypertensive agents and, together with diuretics, have been the cornerstone of pioneering studies showing their benefits on cardiovascular morbidity and mortality as a consequence of blood pressure reduction in patients with hypertension. However, evidence from recent meta-analyses have demonstrated no benefit afforded by atenolol compared with placebo in risk of mortality, myocardial infarction, or stroke, and a higher risk of mortality and stroke with atenolol/propranolol compared with other antihypertensive drug classes. Thus, the effect of these agents on cardiovascular morbidity and mortality in hypertensive patients, especially their use in uncomplicated hypertension, has remained largely controversial. However, it is recognized that the clinical studies used in these meta-analyses were mainly based on the older second-generation β-blockers, such as atenolol and metoprolol. Actually, considerable heterogeneity in, eg, pharmacokinetic, pharmacological, and physicochemical properties exists across the different classes of β-blockers, particularly between the second-generation and newer third-generation agents. Carvedilol is a vasodilating noncardioselective third-generation β-blocker, without the negative hemodynamic and metabolic effects of traditional β-blockers, which can be used as a cardioprotective agent. Compared with conventional β-blockers, carvedilol maintains cardiac output, has a reduced prolonged effect on heart rate, and reduces blood pressure by decreasing vascular resistance. Studies have also shown that carvedilol exhibits favorable effects on metabolic parameters, eg, glycemic control, insulin sensitivity, and lipid metabolism, suggesting that it could be considered in the treatment of patients with metabolic syndrome or diabetes. The present report provides an overview of the main clinical studies concerning carvedilol administered as either monotherapy or in combination with another antihypertensive or more frequently a diuretic agent, with particular focus on the additional benefits beyond blood pressure reduction.

Nebivolol: impact on cardiac and endothelial function and clinical utility

Endothelial dysfunction is a systemic pathological state of the endothelium characterized by a reduction in the bioavailability of vasodilators, essentially nitric oxide, leading to impaired endothelium-dependent vasodilation, as well as disarrangement in vascular wall metabolism and function. One of the key factors in endothelial dysfunction is overproduction of reactive oxygen species which participate in the development of hypertension, atherosclerosis, diabetes, cardiac hypertrophy, heart failure, ischemia-reperfusion injury, and stroke. Because impaired endothelial activity is believed to have a major causal role in the pathophysiology of vascular disease, hypertension, and heart failure, therapeutic agents which modify this condition are of clinical interest. Nebivolol is a third-generation β-blocker with high selectivity for β1-adrenergic receptors and causes vasodilation by interaction with the endothelial L-arginine/ nitric oxide pathway. This dual mechanism of action underscores several hemodynamic qualities of nebivolol, which include reductions in heart rate and blood pressure and improvements in systolic and diastolic function. Although nebivolol reduces blood pressure to a degree similar to that of conventional β-blockers and other types of antihypertensive drugs, it may have advantages in populations with difficult-to-treat hypertension, such as patients with heart failure along with other comorbidities, like diabetes and obesity, and elderly patients in whom nitric oxide-mediated endothelial dysfunction may be more pronounced. Furthermore, recent data indicate that nebivolol appears to be a cost-effective treatment for elderly patients with heart failure compared with standard care. Thus, nebivolol is an effective and well tolerated agent with benefits above those of traditional β-blockers due to its influence on nitric oxide release, which give it singular hemodynamic effects, cardioprotective activity, and a good tolerability profile. This paper reviews the pharmacology structure and properties of nebivolol, focusing on endothelial dysfunction, clinical utility, comparative efficacy, side effects, and quality of life in general with respect to the other antihypertensive agents.