Systolic time intervals as possible predictors of pressure response to sustained beta-adrenergic blockade in arterial hypertension. A within-patient, placebo-controlled study

Blood pressure lowering efficacy of beta-1 selective beta blockers for primary hypertension

BACKGROUND

Beta blockers are commonly used to treat hypertension. The blood pressure reading is the primary tool for physicians and patients to assess the efficacy of the treatment. The blood pressure lowering effect of beta-1 selective blockers is not known.

OBJECTIVES

To quantify the dose-related effects of various doses and types of beta-1 selective adrenergic receptor blockers on systolic and diastolic blood pressure versus placebo in people with primary hypertension.

SEARCH METHODS

We searched the Database of Abstracts of Reviews of Effectiveness (DARE) for related reviews.We searched the following databases for primary studies: the Cochrane Hypertension Specialised Register (All years to 15 October 2015), CENTRAL via the Cochrane Register of Studies Online (2015, Issue 10), Ovid MEDLINE (1946 to 15 October 2015), Ovid EMBASE (1974 to 15 October 2015) and ClinicalTrials.gov (all years to 15 October 2015).The Hypertension Group Specialised Register includes controlled trials from searches of CAB Abstracts, CINAHL, Cochrane Central Register of Controlled Trials, EMBASE, Food Science and Technology Abstracts (FSTA), Global Health, LILACS, MEDLINE, ProQuest Dissertations & Theses, PsycINFO, Web of Science and the WHO International Clinical Trials Registry Platform (ICTRP).Electronic databases were searched using a strategy combining the Cochrane Highly Sensitive Search Strategy for identifying randomized trials in MEDLINE: sensitivity-maximizing version (2008 revision) with selected MeSH terms and free text terms. No language restrictions were used. The MEDLINE search strategy was translated into CENTRAL, EMBASE, the Hypertension Group Specialised Register and ClinicalTrials.gov using the appropriate controlled vocabulary as applicable. Full strategies are in Appendix 1.

SELECTION CRITERIA

Randomised, double-blind, placebo-controlled parallel or cross-over trials. Studies had to contain a beta blocker monotherapy arm with fixed dose. People enrolled into the studies had to have primary hypertension at baseline. Duration of studies had to be between 3 weeks to 12 weeks. Drugs in this class of beta blockers are atenolol, betaxolol, bevantolol, bisoprolol, esmolol, metoprolol, nebivolol, pafenolol, practolol.

DATA COLLECTION AND ANALYSIS

Two authors confirmed the inclusion of studies and extracted the data independently. Review Manager (RevMan) 5.3.5 was used to synthesise data.

MAIN RESULTS

We identified 56 RCTs (randomised controlled trials) that examined the blood pressure (BP) lowering efficacy of beta-1 selective blockers (beta-1 blocker) in 7812 primary hypertensive patients. Among the included trials, 26 RCTs were parallel studies and 30 RCTs were cross-over studies, examining eight beta-1 blockers. Overall, the majority of beta-1 blockers studied significantly lowered systolic blood pressure (SBP) and diastolic blood pressure (DBP). In people with mild to moderate hypertension, beta-1 selective blockers lowered BP by an average of -10/-8 mmHg and reduced heart rate by 11 beats per minute. The maximum BP reduction of beta-1 blockers occurred at twice the starting dose. Individual beta-1 blockers did not exhibit a graded dose-response effect on SBP and DBP over the recommended dose range.Most beta-1 blockers tested significantly lowered heart rate. A graded dose-response of beta-1 blockers on heart rate was evident. Higher dose beta-1 blockers lowered heart rate more than lower doses. Individually and overall beta-1 blockers did not affect pulse pressure, which distinguishes them from other classes of drugs.

AUTHORS' CONCLUSIONS

This review provides low quality evidence that in people with mild to moderate hypertension, beta-1 selective blockers lowered BP by an average of -10/-8 mmHg and reduced heart rate by 11 beats per minute as compared to placebo. The effect of beta-1 blockers at peak hours, -12/-9 mmHg, was greater than the reduction at trough hours, -8/-7 mmHg. Beta-1 selective blockers lowered BP by a greater magnitude than dual receptor beta-blockers and partial agonist beta-blockers, lowered BP similarly to nonselective beta-blockers. Beta-1 selective blockers lowered SBP by a similar degree and lowered DBP by a greater degree than diuretics, angiotensin converting enzyme inhibitors and angiotensin receptor blockers. Because DBP is lowered by a similar extent to SBP, beta-1 selective blockers do not reduce pulse pressure.

Reversal of subclinical left ventricular dysfunction by antihypertensive treatment: a prospective trial of nebivolol against metoprolol

OBJECTIVES

To assess the effects of antihypertensive treatment on subclinical left ventricular dysfunction and to compare the effects of nebivolol with metoprolol.

METHODS

This is a prospective, randomized, parallel, active-controlled, PROBE design study (ClinicalTrials.org: NCT00942487) in 60 patients (53±9 years, 67% men) with arterial hypertension, left ventricular hypertrophy, normal ejection fraction, and no coronary heart disease, randomized to either a nebivolol-based or a metoprolol-based treatment, who had conventional and tissue Doppler echocardiography, at rest and during dobutamine stress, at baseline and after 6 months.

RESULTS

SBP and DBP, and resting heart rate decreased by 13, 13, and 12%, respectively, on nebivolol, and by 11, 13, and 7%, respectively, on metoprolol (all, P<0.01). Mean longitudinal early diastolic velocity increased by 16% (P<0.05) on nebivolol compared with 9% (P=not significant) on metoprolol (P=not significant for intergroup differences), whereas flow propagation velocity increased by 34% on nebivolol (P<0.05) and did not change on metoprolol (P<0.01 for intergroup differences). Mean longitudinal displacement increased by 10% on nebivolol (P<0.05) and did not change on metoprolol (P<0.05 for intergroup differences), whereas ejection time increased by 5% on nebivolol (P<0.05) and did not change on metoprolol. All the other parameters of left ventricular function were not different between the two treatment arms.

CONCLUSION

Patients with mild-to-moderate hypertension have a beneficial effect from 6-month antihypertensive treatment on diastolic longitudinal left ventricular function; effects are significant with nebivolol, but not with metoprolol.

Isometric arm counter-pressure maneuvers to abort impending vasovagal syncope

OBJECTIVES

We hypothesized that isometric arm exercises were able to increase blood pressure (BP) during the phase of impending vasovagal syncope and allow the patient to avoid losing consciousness.

BACKGROUND

Hypotension is always present during the prodromal phase of vasovagal syncope.

METHODS

We evaluated the effect of handgrip (HG) and arm-tensing in 19 patients affected by tilt-induced vasovagal syncope. The study consisted of an acute single-blind, placebo-controlled, randomized, cross-over tilt-table efficacy study and a clinical follow-up feasibility study.

RESULTS

In the acute tilt study, HG was administered for 2 min, starting at the time of onset of symptoms of impending syncope. In the active arm, HG caused an increase in systolic blood pressure (SBP) from 92 +/- 10 mm Hg to 105 +/- 38 mm Hg, whereas in the placebo arm SBP decreased from 91 +/- 11 mm Hg to 73 +/- 21 mm Hg (p = 0.008). Heart rate behavior was similar in the two arms. In the active arm, 63% of patients became asymptomatic, versus 11% in the control arm (p = 0.02); conversely, only 5% of patients developed syncope, versus 47% in the control arm (p = 0.01). The patients were trained to self-administer arm-tensing treatment as soon as symptoms of impending syncope occurred. During 9 +/- 3 months of follow-up, the treatment was actually performed in 95/97 episodes of impending syncope (98%) and was successful in 94/95 (99%). No patients suffered injury or other adverse morbidity related to the relapses.

CONCLUSIONS

Isometric arm contraction is able to abort impending vasovagal syncope by increasing systemic BP. Arm counter-pressure maneuvers can be proposed as a new, feasible, safe, and well accepted first-line treatment for vasovagal syncope.

The analysis of systolic and diastolic time intervals: a more sensitive non-invasive method in the assessment of left ventricular dysfunction in the patients with essential hypertension

Time indices and volumetric parameters were investigated in patients with essential hypertension subdivided into three groups according to the WHO stage classification. The ratio of ejection time (ET) and pre-ejection period (PEP), ET/PEP remained within normal range in WHO-I but decreased significantly in WHO-II and reached extremely low values in WHO-III. ET did not change in WHO-I and WHO-II but became significantly reduced in WHO-III. Prolongation of PEP in WHO-II and WHO-III increased with progression of hypertensive stage. Isovolumic relaxation time (IRT) showed the same pattern as the prolongation of PEP; positive correlation between PEP and IRT was observed (r=0.55). On the other hand, significant changes of volumetric parameters were only observed in WHO-III. These results indicated that the time indices were a more sensitive parameter than the volumetric ones in the assessment of left ventricular dysfunction in the patients with essential hypertension.