The effect of losartan on global and focal cerebral perfusion and on renal function in hypertensives in mild early ischaemic stroke

The PASTIS trial: Testing tadalafil for possible use in vascular cognitive impairment

INTRODUCTION

There are few randomized clinical trials in vascular cognitive impairment (VCI). This trial tested the hypothesis that the PDE5 inhibitor tadalafil, a widely used vasodilator, increases cerebral blood flow (CBF) in older people with symptomatic small vessel disease, the main cause of VCI.

METHODS

In a double-blind, placebo-controlled, cross-over trial, participants received tadalafil (20 mg) and placebo on two visits ≥7 days apart (randomized to order of treatment). The primary endpoint, change in subcortical CBF, was measured by arterial spin labelling.

RESULTS

Tadalafil increased CBF non-significantly in all subcortical areas (N = 55, age: 66.8 (8.6) years) with greatest treatment effect within white matter hyperintensities (+9.8%, P = .0960). There were incidental treatment effects on systolic and diastolic blood pressure (-7.8, -4.9 mmHg; P < .001). No serious adverse events were observed.

DISCUSSION

This trial did not identify a significant treatment effect of single-administration tadalafil on subcortical CBF. To detect treatment effects may require different dosing regimens.

Effect of drug interventions on cerebral hemodynamics in ischemic stroke patients

The ischemic penumbra is sensitive to alterations in cerebral perfusion. A myriad of drugs are used in acute ischemic stroke (AIS) management, yet their impact on cerebral hemodynamics is poorly understood. As part of the Cerebral Autoregulation Network led INFOMATAS project (Identifying New Targets for Management and Therapy in Acute Stroke), this paper reviews some of the most common drugs a patient with AIS will come across and their potential influence on cerebral hemodynamics with a particular focus being on cerebral autoregulation (CA). We first discuss how compounds that promote clot lysis and prevent clot formation could potentially impact cerebral hemodynamics, before focusing on how the different classes of antihypertensive drugs can influence cerebral hemodynamics. We discuss the different properties of each drug and their potential impact on cerebral perfusion and CA. With emerging interest in CA status of AIS patients, either during or soon after treatment when timely reperfusion and salvageable tissue is at its most critical, the properties of these pharmacological agents may be relevant for modelling cerebral perfusion accuracy and for setting individualised treatment strategies.

Age-specific cerebral haemodynamic effects of early blood pressure lowering after transient ischaemic attack and non-disabling stroke

INTRODUCTION

There is limited knowledge of the effects of blood pressure (BP) lowering on cerebral haemodynamics after transient ischaemic attack (TIA) and non-disabling stroke, particularly at older ages. We aimed to evaluate changes in transcranial Doppler (TCD) haemodynamic indices in patients undergoing early blood pressure lowering after TIA/non-disabling stroke, irrespective of age.

PATIENTS AND METHODS

Among consecutive eligible patients attending a rapid-access clinic with suspected TIA/non-disabling stroke and no evidence of extra/intracranial stenosis, hypertensive ones underwent intensive BP-lowering guided by daily home telemetric blood pressure monitoring (HBPM). Clinic-based BP, HBPM, End-tidal CO2 and bilateral middle cerebral artery (MCA) velocity on TCD were compared in the acute setting versus one-month follow-up; changes were stratified by baseline hypertension (clinic-BP≥140/90) and by age (<65, 65-79 and ≥80).

RESULTS

In 697 patients with repeated TCD measures, mean/SD baseline systolic-BP (145.0/21.3 mmHg) was reduced by an average of 11.3/19.9 mmHg (p < 0.0001) at one-month (133.7/17.4 mmHg), driven by patients hypertensive at baseline (systolic-BP change = -19.0/19.2 mmHg, p < 0.001; vs -0.5/15.4, p = 0.62 in normotensives). Compared with baseline, a significant change was observed at one-month only in mean/SD MCA end diastolic velocity (EDV) (0.77/7.26 cm/s, p = 0.005) and in resistance index (RI) (-0.005/0.051, p = 0.016), driven by hypertensive patients (mean/SD EDV change: 1.145/6.96 cm/s p = 0.001, RI change -0.007/0.06, p = 0.014). Findings were similar at all ages (EDV change - ptrend=0.357; RI change - ptrend=0.225), including 117 patients aged ≥80. EDV and RI changes were largest in 100 patients with clinic systolic-BP decrease ≥30 mmHg (mean/SD EDV change = 2.49/7.47 cm/s, p = 0.001; RI change -0.024/0.063, p < 0.0001).

CONCLUSION

There was no evidence of worsening of TCD haemodynamic indices associated with BP-lowering soon after TIA/non-disabling stroke, irrespective of age and degree of BP reduction. In fact, EDV increase and RI decrease observed after treatment of hypertensive patients suggest a decrease in distal vascular resistance.

The Role of Sartans in the Treatment of Stroke and Subarachnoid Hemorrhage: A Narrative Review of Preclinical and Clinical Studies

Background: Delayed cerebral vasospasm (DCVS) due to aneurysmal subarachnoid hemorrhage (aSAH) and its sequela, delayed cerebral ischemia (DCI), are associated with poor functional outcome. Endothelin-1 (ET-1) is known to play a major role in mediating cerebral vasoconstriction. Angiotensin-II-type-1-receptor antagonists such as Sartans may have a beneficial effect after aSAH by reducing DCVS due to crosstalk with the endothelin system. In this review, we discuss the role of Sartans in the treatment of stroke and their potential impact in aSAH. Methods: We conducted a literature research of the MEDLINE PubMed database in accordance with PRISMA criteria on articles published between 1980 to 2019 reviewing: "Sartans AND ischemic stroke". Of 227 studies, 64 preclinical and 19 clinical trials fulfilled the eligibility criteria. Results: There was a positive effect of Sartans on ischemic stroke in both preclinical and clinical settings (attenuating ischemic brain damage, reducing cerebral inflammation and infarct size, increasing cerebral blood flow). In addition, Sartans reduced DCVS after aSAH in animal models by diminishing the effect of ET-1 mediated vasoconstriction (including cerebral inflammation and cerebral epileptogenic activity reduction, cerebral blood flow autoregulation restoration as well as pressure-dependent cerebral vasoconstriction). Conclusion: Thus, Sartans might play a key role in the treatment of patients with aSAH.

Cerebral Hemodynamic Evaluation After Cerebral Recanalization Therapy for Acute Ischemic Stroke

Cerebral recanalization therapy, either intravenous thrombolysis or mechanical thrombectomy, improves the outcomes in patients with acute ischemic stroke (AIS) by restoring the cerebral perfusion of the ischemic penumbra. Cerebral hemodynamic evaluation after recanalization therapy, can help identify patients with high risks of reperfusion-associated complications. Among the various hemodynamic modalities, magnetic resonance imaging (MRI), computed tomography perfusion, and transcranial Doppler sonography (TCD) are the most commonly used. Poststroke hypoperfusion is associated with infarct expansion, while hyperperfusion, which once was considered the hallmark of successful recanalization, is associated with hemorrhagic transformation. Either the hypo- or the hyperperfusion may result in poor clinical outcomes. Individual blood pressure target based on cerebral hemodynamic evaluation was crucial to improve the prognosis. This review summarizes literature on cerebral hemodynamic evaluation and management after recanalization therapy to guide clinical decision making.

Dynamic autoregulation of cerebral blood flow measured non-invasively with fast diffuse correlation spectroscopy

Cerebral autoregulation (CA) maintains cerebral blood flow (CBF) in the presence of systemic blood pressure changes. Brain injury can cause loss of CA and resulting dysregulation of CBF, and the degree of CA impairment is a functional indicator of cerebral tissue health. Here, we demonstrate a new approach to noninvasively estimate cerebral autoregulation in healthy adult volunteers. The approach employs pulsatile CBF measurements obtained using high-speed diffuse correlation spectroscopy (DCS). Rapid thigh-cuff deflation initiates a chain of responses that permits estimation of rates of dynamic autoregulation in the cerebral microvasculature. The regulation rate estimated with DCS in the microvasculature (median: 0.26 s-1, inter quartile range: 0.19 s-1) agrees well (R = 0.81, slope = 0.9) with regulation rates measured by transcranial Doppler ultrasound (TCD) in the proximal vasculature (median: 0.28 s-1, inter quartile range: 0.10 s-1). We also obtained an index of systemic autoregulation in concurrently measured scalp microvasculature. Systemic autoregulation begins later than cerebral autoregulation and exhibited a different rate (0.55 s-1, inter quartile range: 0.72 s-1). Our work demonstrates the potential of diffuse correlation spectroscopy for bedside monitoring of cerebral autoregulation in the microvasculature of patients with brain injury.

Low blood pressure during the acute period of ischemic stroke is associated with decreased survival

OBJECTIVES

There is no agreement on optimal blood pressure (BP) level during the acute phase of stroke, because studies on the relation between BP and stroke outcome have shown contradicting results. The aim of this study was to compare the relationship of admission, maximal, discharge BP and its components during hospitalization for the first-ever acute ischemic stroke with total mortality after stroke.

METHODS

In 532 consecutive patients (mean age 66 ± 10 years, 59% of men) hospitalized for their first-ever ischemic stroke, the association between BP and total mortality during a median follow-up of 66 weeks (interquartile range 33-119 weeks) was analyzed.

RESULTS

In multivariate analysis, both admission mean BP (MBP) and discharge SBP quartiles were independent predictors of mortality and outperformed other parameters of BP. After multivariate adjustments, patients with admission MBP below 100 mmHg had a higher risk of death than those with MBP between 100-110 and 110-121 mmHg, whereas the risk of mortality did not differ from the group with admission MBP above 122 mmHg. Similarly, patients with discharge SBP below 120 mmHg had an increased risk of death as compared to groups with SBP between 120-130 and 130-141 mmHg, whereas the risk of death was similar to that with discharge SBP above 141 mmHg.

CONCLUSION

Among patients hospitalized for their first-ever ischemic stroke, the risk of all-cause death is significantly increased in those with admission MBP below 100 mmHg and discharge SBP below 120 mmHg, even after adjustments for other confounders.

Interventions for deliberately altering blood pressure in acute stroke

BACKGROUND

It is unclear whether blood pressure should be altered actively during the acute phase of stroke. This is an update of a Cochrane review first published in 1997, and previously updated in 2001 and 2008.

OBJECTIVES

To assess the clinical effectiveness of altering blood pressure in people with acute stroke, and the effect of different vasoactive drugs on blood pressure in acute stroke.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (last searched in February 2014), the Cochrane Database of Systematic reviews (CDSR) and the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2014, Issue 2), MEDLINE (Ovid) (1966 to May 2014), EMBASE (Ovid) (1974 to May 2014), Science Citation Index (ISI, Web of Science, 1981 to May 2014) and the Stroke Trials Registry (searched May 2014).

SELECTION CRITERIA

Randomised controlled trials of interventions that aimed to alter blood pressure compared with control in participants within one week of acute ischaemic or haemorrhagic stroke.

DATA COLLECTION AND ANALYSIS

Two review authors independently applied the inclusion criteria, assessed trial quality and extracted data. The review authors cross-checked data and resolved discrepancies by discussion to reach consensus. We obtained published and unpublished data where available.

MAIN RESULTS

We included 26 trials involving 17,011 participants (8497 participants were assigned active therapy and 8514 participants received placebo/control). Not all trials contributed to each outcome. Most data came from trials that had a wide time window for recruitment; four trials gave treatment within six hours and one trial within eight hours. The trials tested alpha-2 adrenergic agonists (A2AA), angiotensin converting enzyme inhibitors (ACEI), angiotensin receptor antagonists (ARA), calcium channel blockers (CCBs), nitric oxide (NO) donors, thiazide-like diuretics, and target-driven blood pressure lowering. One trial tested phenylephrine.At 24 hours after randomisation oral ACEIs reduced systolic blood pressure (SBP, mean difference (MD) -8 mmHg, 95% confidence interval (CI) -17 to 1) and diastolic blood pressure (DBP, MD -3 mmHg, 95% CI -9 to 2), sublingual ACEIs reduced SBP (MD -12.00 mm Hg, 95% CI -26 to 2) and DBP (MD -2, 95%CI -10 to 6), oral ARA reduced SBP (MD -1 mm Hg, 95% CI -3 to 2) and DBP (MD -1 mm Hg, 95% CI -3 to 1), oral beta blockers reduced SBP (MD -14 mm Hg; 95% CI -27 to -1) and DBP (MD -1 mm Hg, 95% CI -9 to 7), intravenous (iv) beta blockers reduced SBP (MD -5 mm Hg, 95% CI -18 to 8) and DBP (-5 mm Hg, 95% CI -13 to 3), oral CCBs reduced SBP (MD -13 mmHg, 95% CI -43 to 17) and DBP (MD -6 mmHg, 95% CI -14 to 2), iv CCBs reduced SBP (MD -32 mmHg, 95% CI -65 to 1) and DBP (MD -13, 95% CI -31 to 6), NO donors reduced SBP (MD -12 mmHg, 95% CI -19 to -5) and DBP (MD -3, 95% CI -4 to -2) while phenylephrine, non-significantly increased SBP (MD 21 mmHg, 95% CI -13 to 55) and DBP (MD 1 mmHg, 95% CI -15 to 16).Blood pressure lowering did not reduce death or dependency either by drug class (OR 0.98, 95% CI 0.92 to 1.05), stroke type (OR 0.98, 95% CI 0.92 to 1.05) or time to treatment (OR 0.98, 95% CI 0.92 to 1.05). Treatment within six hours of stroke appeared effective in reducing death or dependency (OR 0.86, 95% CI 0.76 to 0.99) but not death (OR 0.70, 95% CI 0.38 to 1.26) at the end of the trial. Although death or dependency did not differ between people who continued pre-stroke antihypertensive treatment versus those who stopped it temporarily (worse outcome with continuing treatment, OR 1.06, 95% CI 0.91 to 1.24), disability scores at the end of the trial were worse in participants randomised to continue treatment (Barthel Index, MD -3.2, 95% CI -5.8, -0.6).

AUTHORS' CONCLUSIONS

There is insufficient evidence that lowering blood pressure during the acute phase of stroke improves functional outcome. It is reasonable to withhold blood pressure-lowering drugs until patients are medically and neurologically stable, and have suitable oral or enteral access, after which drugs can than be reintroduced. In people with acute stroke, CCBs, ACEI, ARA, beta blockers and NO donors each lower blood pressure while phenylephrine probably increases blood pressure. Further trials are needed to identify which people are most likely to benefit from early treatment, in particular whether treatment started very early is beneficial.

Cerebral autoregulation and acute ischemic stroke

Cerebral autoregulation tightly controls blood flow to the brain by coupling cerebral metabolic demand to cerebral perfusion. In the setting of acute brain injury, such as that caused by ischemic stroke, the continued precise control of cerebral blood flow (CBF) is vital to prevent further injury. Chronic as well as acute elevations in blood pressure are frequently associated with stroke, therefore, understanding the physiological response of the brain to the treatment of hypertension is clinically important. Physiological data obtained in patients with acute ischemic stroke provide no clear evidence that there are alterations in the intrinsic autoregulatory capacity of cerebral blood vessels, except perhaps in infarcted tissue. While it is likely safe to modestly reduce blood pressure by 10-15 mm Hg in most patients with acute ischemic stroke, to date, there are no controlled trial data to indicate that reducing blood pressure is beneficial. There may be subgroups, such as those with persistent large vessel occlusion, large infarcts with edema causing increased intracranial pressure or local mass effect, or chronic hypertension, in which blood pressure reduction may lead to impaired cerebral perfusion in noninfarcted tissue.

The effect of antihypertensive treatment on headache and blood pressure variability in randomized controlled trials: a systematic review

Antihypertensive drugs reduce headache but it is unclear whether there are differences between drug classes. Calcium channel blockers (CCBs) decrease variability in systolic blood pressure (SBPV) and stroke risk more than other classes, possibly due to decreased vascular tone. If so, there might be a correlation between drug-class effects on variability in SBP and on headache. We determined antihypertensive class effects on SBPV and headache during follow-up in a systematic review of randomized controlled trials. We determined pooled estimates of treatment effect on group variability in BP (variance ratio, VR) and on the odds ratio for headache (OR) by random-effects meta-analysis. Antihypertensive drugs reduced the incidence of headache compared to placebo (OR = 0.75, 95% CI 0.69-0.82, p < 0.0001, 198 comparisons, 43,672 patients), but there was significant heterogeneity between drug classes (p = 0.0007) with a greater effect of beta-blockers compared to placebo (VR = 0.49, 0.33-0.68, p < 0.0001, 16 trials) or all other drug classes (OR = 0.73, 0.62-0.85, p = 0.0002, 49 trials) and a lack of effectiveness of CCBs (vs. placebo-OR = 0.95, 0.79-1.15, 65 trials; vs. other drugs-OR = 1.19, 1.05-1.35, p = 0.009, 101 trials). Drug-class effects on headache were opposite to effects on variability in SBP (vs. other drugs: CCB-VR = 0.81, 0.71-0.85, p < 0.0001; beta-blocker VR = 1.17, 1.07-1.28, p < 0.0001), but were unrelated to differences in mean SBP. Antihypertensive drugs reduce headache but the effect differs between classes, corresponding to their effects on SBPV and the risk of stroke. This may partly be explained by consistent antihypertensive class effects on vascular tone in the peripheral (variability) and cerebrovascular circulations (headache).

A Randomized Placebo Controlled Trial of Early Treatment of Acute Ischemic Stroke with Atorvastatin and Irbesartan

Background

Cholesterol and blood pressure lowering therapies are effective in the secondary prevention of ischemic stroke.

Aim

To determine whether 30 days of treatment with atorvastatin, or irbesartan, initiated within 96 h of symptom onset improves recovery from acute ischemic stroke.

Methods

Eighty-one patients with acute ischemic stroke participated in this double-blind, placebo-controlled, randomized trial of atorvastatin (80 mg) vs. placebo, and/or irbesartan (150 mg) vs. placebo. Fifty-two patients (randomized 53 ± 22 h after onset of symptoms) completed the 30-day primary outcome follow-up.

Results

The primary outcome, maximal brain infarct size at days 3 and 30 measured by perfusion computed tomography, was not significantly altered by random assignment to irbesartan (1088 (IQR 216, 2594) mm2 at day 3, compared with 398 (144, 2053) mm2 among the placebo group, P=0·79 controlling for baseline values; and 822 (159, 1717) mm2 at day 30, cf 280 (76, 1330) mm2; P=0·63); or atorvastatin (454 (107, 1765) mm2 cf 825 (265, 2509) mm2 at day 3; P=0·33; and 462 (43, 1399) mm2 cf 280 (128, 1559) mm2 at day 30, P=0·79). There were no other significant differences among the treatment groups with the exception of: • high sensitivity C-reactive protein concentrations, which were lower in the irbesartan treatment group at day 30 (mean difference 12·6 mg/L; 95% CI: −25·1, −0·1; P=0·048); and • the mean cerebral blood flow in the affected cerebral hemisphere at 30 days after stroke, which was significantly reduced by random assignment to irbesartan compared with placebo in both the affected cerebral hemisphere (−7·5 mL/100 mL/min (95% CI: −1·7 to −13·4, P=0·01)) and in the unaffected hemisphere (−7·3 mL/100 mL/min (95% CI: −1·3, −13·4; P=0·02)). Atorvastatin therapy was well tolerated, but irbesartan therapy was associated with an increased rate of withdrawal from therapy ( n=10 (29%), compared with n=3 (9%) who withdrew from placebo, P=0·04).

Conclusions

Treatment with atorvastatin and irbesartan, initiated on day 3 after acute ischemic stroke, did not appear to substantially modify infarct growth.

Vasoactive drugs for acute stroke

BACKGROUND

It is unclear whether blood pressure (BP) should be altered actively during the acute phase of stroke.

OBJECTIVES

To assess the effect of lowering or elevating BP in people with acute stroke, and the effect of different vasoactive drugs on BP in acute stroke.

SEARCH STRATEGY

We searched the Cochrane Stroke Group Trials Register (last searched June 2009), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 4, 2009), MEDLINE (1966 to October 2009), EMBASE (1980 to October 2009), and Science Citation Index (1981 to October 2009).

SELECTION CRITERIA

Randomised trials of interventions that would be expected, on pharmacological grounds, to alter BP in patients within one week of the onset of acute stroke.

DATA COLLECTION AND ANALYSIS

Two review authors independently applied the trial inclusion criteria, assessed trial quality, and extracted data.

MAIN RESULTS

We identified 131 trials involving in excess of 18,000 patients; a further 13 trials are ongoing. We obtained data for 43 trials (7649 patients). Among BP-lowering trials, beta receptor antagonists lowered BP (early systolic BP (SBP) mean difference (MD) -6.1 mmHg, 95% CI -11.4 to -0.9; late SBP MD -4.9 mmHg, 95% CI -10.2 to 0.4; late diastolic BP (DBP) MD -4.5 mmHg, 95% CI -7.8 to -1.2). Oral calcium channel blockers (CCB) lowered BP (late SBP MD -3.2 mmHg, 95% CI -5.4 to -1.1; early DBP MD -2.5, 95% CI -5.6 to 0.7; late DBP MD -2.1, 95% CI -3.5 to -0.7). Nitric oxide donors lowered BP (early SBP MD -10.3 mmHg, 95% CI -17.6 to -3.0). Prostacyclin lowered BP (late SBP MD, -7.7 mmHg, 95% CI -15.6 to 0.2; late DBP MD -3.9 mmHg, 95% CI -8.1 to 0.4). Among BP-increasing trials, diaspirin cross-linked haemoglobin (DCLHb) increased BP (early SBP MD 15.3 mmHg, 95% CI 4.0 to 26.6; late SBP MD 15.9 mmHg, 95% CI 1.8 to 30.0). None of the drug classes significantly altered outcome apart from DCLHb which increased combined death or dependency (odds ratio (OR) 5.41, 95% CI 1.87 to 15.64).

AUTHORS' CONCLUSIONS

There is not enough evidence to evaluate reliably the effect of altering BP on outcome after acute stroke. However, treatment with DCLHb was associated with poor clinical outcomes. Beta receptor antagonists, CCBs, nitric oxide, and prostacyclin each lowered BP during the acute phase of stroke. In contrast, DCLHb increased BP.

Blood pressure lowering with valsartan is associated with maintenance of cerebral blood flow and cerebral perfusion reserve in hypertensive patients with cerebral small vessel disease

BACKGROUND

The purpose of this study was to determine the effect of systemic blood pressure-lowering treatment with an angiotensin II receptor blocker, valsartan, on cerebral hemodynamics in patients with hypertension and evidence of cerebral small vessel disease.

METHODS

We used positron emission tomography and acetazolamide challenge tests to measure cerebral blood flow (CBF) and cerebrovascular reserve (CVR) in 8 patients with hypertension (mean age 70.8 years) with lacunar infarcts and white matter lesions before and after valsartan therapy.

RESULTS

Systemic blood pressure was significantly decreased from baseline after treatment with valsartan. The baseline global CBFs before and after treatment were 38.2 +/- 5.6 mL/min/100 g and 39.9 +/- 9.0 mL/min/100 g, respectively. The CVRs before and after treatment were 52.2 +/- 18.4% and 39.7 +/- 18.9%, respectively. Differences in these parameters were not significant. Both regional CBF and CVR in the corona radiata with moderate or severe white matter lesions were also preserved after valsartan therapy compared with those before treatment.

CONCLUSIONS

Cerebral hemodynamics were preserved after blood pressure lowering with valsartan therapy. Valsartan could be a feasible antihypertensive regimen in terms of cerebral circulation in patients with cerebral small vessel disease.

Effect of cilnidipine vs losartan on cerebral blood flow in hypertensive patients with a history of ischemic stroke: a randomized controlled trial

OBJECTIVES

The aim of this study was to compare the effects of antihypertensive agents on cerebral blood flow (CBF) in hypertensive patients with previous ischemic stroke.

MATERIALS AND METHODS

In this double-blind, multi-center, non-inferiority trial, 196 patients were randomized to cilnidipine 10-20 mg or losartan 50-100 mg once daily for 4 weeks. Baseline and follow-up CBF as measured by single photon emission computed tomography were obtained in 167. The primary endpoint was the global CBF change. The secondary endpoints were the CBF change in the hemisphere ipsilateral to the index stroke, non-impairment of global CBF and blood pressure (BP) reduction.

RESULTS

Global CBF increased significantly in the cilnidipine arm (9.0 +/- 29.6%, P = 0.0071) and the losartan arm (11.4 +/- 31.4%, P = 0.0012), and these changes were not different between the two groups (P = 0.607). However, the estimated difference in percentage global CBF change between the two groups was -2.43% (97.5% CI, -13.06% to 8.21%), which crossed the predetermined non-inferiority margin of -8.6%. Ipsilesional hemispheric CBF change, non-impairment of global CBF and BP reduction were similar in the two groups.

CONCLUSIONS

This trial failed to prove the non-inferiority of cilnidipine to losartan regarding global CBF change. Both the treatments, however, increase the global CBF despite BP lowering.

Interventions for deliberately altering blood pressure in acute stroke

BACKGROUND

It is unclear whether blood pressure should be altered actively during the acute phase of stroke. This is an update of a Cochrane review first published in 1997, and previously updated in 2001.

OBJECTIVES

To assess the effect of altering blood pressure in people with acute stroke, and the effect of different vasoactive drugs on blood pressure in acute stroke.

SEARCH STRATEGY

We searched the Cochrane Stroke Group Trials Register (last searched July 2007), the Cochrane Database of Systematic Reviews and Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 2 2008), MEDLINE, EMBASE and other databases, reference lists of relevant publications and contacted researchers in the field.

SELECTION CRITERIA

Randomised controlled trials of interventions that aimed to alter blood pressure in patients within one week of acute ischaemic or haemorrhagic stroke.

DATA COLLECTION AND ANALYSIS

Two review authors independently applied the inclusion criteria, assessed trial quality and extracted data.

MAIN RESULTS

Twelve trials involving 1153 participants were included (603 participants were assigned active therapy and 550 participants received placebo/control). The trials tested angiotensin converting enzyme inhibitors (ACEI), angiotensin receptor antagonists (ARA), calcium channel blockers (CCBs), clonidine, glyceryl trinitrate (GTN), thiazide diuretic and mixed antihypertensive therapy. One trial tested phenylephrine. At 24 hours after randomisation ACEIs reduced systolic blood pressure (SBP, mean difference, MD -6 mmHg, 95% confidence interval, CI -22 to 10) and diastolic blood pressure (DBP, MD -5 mmHg, 95% CI -18 to 7), ARA reduced SBP (MD -3, 95% CI -7 to 2) and DBP (MD -3, 95% CI -6 to 0.4), iv CCBs reduced SBP (MD -32 mmHg, 95% CI -65 to 1) and DBP (MD -13 mmHg, 95% CI -31 to 6), oral CCBs reduced SBP (MD -13 mmHg, 95% , CI -43 to 17) and DBP (MD -6 mmHg, 95% CI -14 to 2), GTN reduced SBP (MD -10 mmHg, 95% CI -18 to -3) and DBP (MD -1 mmHg, 95% CI -5 to 3) while phenylephrine, non-significantly increased SBP (MD 21 mmHg, 95% CI -13 to 55) and DBP (MD 1 mmHg, 95% CI -15 to 16). Functional outcome and death were not altered by any of the drugs.

AUTHORS' CONCLUSIONS

There is insufficient evidence to evaluate the effect of altering blood pressure on outcome during the acute phase of stroke. In patients with acute stroke, CCBs, ACEI, ARA and GTN each lower blood pressure while phenylephrine probably increases blood pressure.

Transdermal glyceryl trinitrate lowers blood pressure and maintains cerebral blood flow in recent stroke

High blood pressure (BP) is common in acute stroke and is independently associated with a poor outcome. Lowering BP might improve outcome if it did not adversely affect cerebral blood flow (CBF) or cerebral perfusion pressure. We investigated the effect of glyceryl trinitrate ([GTN] an NO donor) on quantitative CBF, BP, and cerebral perfusion pressure in patients with recent stroke. Eighteen patients with recent (<5 days) ischemic (n=16) or hemorrhagic (n=2) stroke were randomly assigned (2:1) to transdermal GTN (5 mg) or control. CBF (global, hemispheric, arterial territory, and lesion, using xenon computed tomography) and BP (peripheral and central) were measured before and 1 hour after treatment with GTN. The effects of GTN on CBF and BP were adjusted for baseline measurements (ANCOVA). GTN lowered peripheral systolic BP by (mean) 23 mm Hg (95% CI, 2 to 45; P=0.03) and central systolic BP by 22 mm Hg (95% CI, 0 to 44; P=0.048). In contrast, GTN did not alter CBF (mL/min per 100 g): global -1.2 (95% CI, -6.5 to 4.2; P=0.66) and ipsilateral hemisphere -1.4 (95% CI, -7.6 to 4.9; P=0.65) or area of stroke oligemia, penumbra, or core (as defined by critical CBF limits). Contralateral CBF did not change: hemisphere 0 (95% CI, -7 to 6; P=0.96). GTN did not alter cerebral perfusion pressure or zero-filling pressure. Significant reductions in BP after transdermal GTN are not associated with changes in CBF or cerebral perfusion pressure or cerebral steal in patients with recent stroke. Trials need to assess the effect of lowering BP on functional outcome.

Effect of Vasoactive Therapy on Cerebral Circulation

Many questions regarding blood pressure management after acute stroke remain unanswered, resulting in an ongoing debate about whether to treat hypertension acutely and how aggressively blood pressure should be lowered. This review discusses normal and altered cerebrophysiology and provides evidence supporting and opposing the active management of blood pressure within the first 24 hours after stroke. Commonly used intravenous antihypertensive agents and their cerebrovascular effects are reviewed, and therapeutic recommendations are given based on the available evidence.

Possible pathophysiologic mechanisms supporting the superior stroke protection of angiotensin receptor blockers compared to angiotensin-converting enzyme inhibitors: clinical and experimental evidence

Stroke is a major cause of death and disability and its incidence increases linearly with age and the level of systolic and diastolic blood pressure. Stroke, besides being a cause of long-term disability for the affected person, also imposes a significant burden on society and healthcare costs. Although good blood pressure control is very critical for stroke prevention, angiotensin receptor blockers (ARBs) may be superior to angiotensin-converting enzyme inhibitors (ACEIs) for the same degree of blood pressure control. This hypothesis has clinical and experimental support. ARBs prevent stroke incidence by blocking the angiotensin II (AII), AT1 receptors preventing brain ischaemia and allowing AII to stimulate the unoccupied AT2 receptors, which improve brain ischaemia. ACEIs, by reducing AII generation, are less effective in preventing stroke. This hypothesis provides evidence that AII plays an important role in the prevention of stroke. Certain ARBs like losartan, and telmisartan, irbesartan and candesartan possess additional properties which may play a role in stroke prevention, which is independent of AII. These include antiplatelet aggregating, hypouricemic, antidiabetic and atrial antifibrillatory effects. However, the most critical factor in stroke prevention is good blood pressure control irrespective of drug used.