Cerebral Perfusion in Hypertensives with Carotid Artery Stenosis: A Comparative Study of Lacidipine and Hydrochlorothiazide

Pharmacological interventions for asymptomatic carotid stenosis

BACKGROUND

Carotid artery stenosis is narrowing of the carotid arteries. Asymptomatic carotid stenosis is when this narrowing occurs in people without a history or symptoms of this disease. It is caused by atherosclerosis; that is, the build-up of fats, cholesterol, and other substances in and on the artery walls. Atherosclerosis is more likely to occur in people with several risk factors, such as diabetes, hypertension, hyperlipidaemia, and smoking. As this damage can develop without symptoms, the first symptom can be a fatal or disabling stroke, known as ischaemic stroke. Carotid stenosis leading to ischaemic stroke is most common in men older than 70 years. Ischaemic stroke is a worldwide public health problem.

OBJECTIVES

To assess the effects of pharmacological interventions for the treatment of asymptomatic carotid stenosis in preventing neurological impairment, ipsilateral major or disabling stroke, death, major bleeding, and other outcomes.

SEARCH METHODS

We searched the Cochrane Stroke Group trials register, CENTRAL, MEDLINE, Embase, two other databases, and three trials registers from their inception to 9 August 2022. We also checked the reference lists of any relevant systematic reviews identified and contacted specialists in the field for additional references to trials.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs), irrespective of publication status and language, comparing a pharmacological intervention to placebo, no treatment, or another pharmacological intervention for asymptomatic carotid stenosis.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures. Two review authors independently extracted the data and assessed the risk of bias of the trials. A third author resolved disagreements when necessary. We assessed the evidence certainty for key outcomes using GRADE.

MAIN RESULTS

We included 34 RCTs with 11,571 participants. Data for meta-analysis were available from only 22 studies with 6887 participants. The mean follow-up period was 2.5 years. None of the 34 included studies assessed neurological impairment and quality of life. Antiplatelet agent (acetylsalicylic acid) versus placebo Acetylsalicylic acid (1 study, 372 participants) may result in little to no difference in ipsilateral major or disabling stroke (risk ratio (RR) 1.08, 95% confidence interval (CI) 0.47 to 2.47), stroke-related mortality (RR 1.40, 95% CI 0.54 to 3.59), progression of carotid stenosis (RR 1.16, 95% CI 0.79 to 1.71), and adverse events (RR 0.81, 95% CI 0.41 to 1.59), compared to placebo (all low-certainty evidence). The effect of acetylsalicylic acid on major bleeding is very uncertain (RR 0.98, 95% CI 0.06 to 15.53; very low-certainty evidence). The study did not measure neurological impairment or quality of life. Antihypertensive agents (metoprolol and chlorthalidone) versus placebo The antihypertensive agent, metoprolol, may result in no difference in ipsilateral major or disabling stroke (RR 0.14, 95% CI 0.02 to1.16; 1 study, 793 participants) and stroke-related mortality (RR 0.57, 95% CI 0.17 to 1.94; 1 study, 793 participants) compared to placebo (both low-certainty evidence). However, chlorthalidone may slow the progression of carotid stenosis (RR 0.45, 95% CI 0.23 to 0.91; 1 study, 129 participants; low-certainty evidence) compared to placebo. Neither study measured neurological impairment, major bleeding, adverse events, or quality of life. Anticoagulant agent (warfarin) versus placebo The evidence is very uncertain about the effects of warfarin (1 study, 919 participants) on major bleeding (RR 1.19, 95% CI 0.97 to 1.46; very low-certainty evidence), but it may reduce adverse events (RR 0.89, 95% CI 0.81 to 0.99; low-certainty evidence) compared to placebo. The study did not measure neurological impairment, ipsilateral major or disabling stroke, stroke-related mortality, progression of carotid stenosis, or quality of life. Lipid-lowering agents (atorvastatin, fluvastatin, lovastatin, pravastatin, probucol, and rosuvastatin) versus placebo or no treatment Lipid-lowering agents may result in little to no difference in ipsilateral major or disabling stroke (atorvastatin, lovastatin, pravastatin, and rosuvastatin; RR 0.36, 95% CI 0.09 to 1.53; 5 studies, 2235 participants) stroke-related mortality (lovastatin and pravastatin; RR 0.25, 95% CI 0.03 to 2.29; 2 studies, 1366 participants), and adverse events (fluvastatin, lovastatin, pravastatin, probucol, and rosuvastatin; RR 0.76, 95% CI 0.53 to1.10; 7 studies, 3726 participants) compared to placebo or no treatment (all low-certainty evidence). The studies did not measure neurological impairment, major bleeding, progression of carotid stenosis, or quality of life.

AUTHORS' CONCLUSIONS

Although there is no high-certainty evidence to support pharmacological intervention, this does not mean that pharmacological treatments are ineffective in preventing ischaemic cerebral events, morbidity, and mortality. High-quality RCTs are needed to better inform the best medical treatment that may reduce the burden of carotid stenosis. In the interim, clinicians will have to use other sources of information.

Psychometric and EEG changes after carotid endarterectomy

The influence of carotid stenosis and its surgical treatment on brain function is still poorly defined. We therefore performed a study to assess psychometric and quantified EEG findings after carotid endarterectomy (CEA). Sixty-nine non-demented patients (aged 72 ± 7 years) with severe carotid stenosis (≥ 70%) eligible for CEA were studied. Forty patients (group A) had unilateral stenosis, and 29 patients (group B) had bilateral stenosis. Before and 5 months after CEA all the patients were evaluated by the Trail Making Test A, the Symbol Digit Test, and spectral EEG analysis. At baseline, compared to group A, group B patients performed slowly the Trail Making Test A (Z: 1.45 ± 1.4 vs. 0.76 ± 1.3; p <  0.05), but not the Symbol Digit Test (Z: 0.83 ± 1.38 vs. 0.64 ± 1.26; p = 0.59). Altogether, the patients with at least one abnormal psychometric test were 29% (group A: 26%; group B: 33%, p = 0.56). The EEG did not differ significantly between patients of group A compared to group B. After CEA, psychometric tests improved (mean Z score from 0.73 ± 1.12 to 0.45 ± 1.15, p <  0.05). The improvement was similar in group A and B. The EEG mean dominant frequency improved only in group B patients and it was related to the improvement in psychometric tests (r = 0.43, p = 0.05). Low psychometric performance was detectable in about 1/ 3 of non-demented patients with severe carotid stenosis. CEA improved mental performance and, in patients with severe bilateral stenosis, accelerated the EEG frequency.

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).

Untreated hypertension decreases heritability of cognition in late middle age

Hypertension is a risk factor for cognitive decline, but the mechanisms underlying the effects of hypertension on cognition, particularly in midlife, are unclear. We examined whether hypertension modifies genetic influences on individual differences in cognition. Nine cognitive domains and general cognitive ability were assessed in a sample of 1,237 male twins aged 51-60 who were divided into three blood pressure groups: non-hypertensive; medicated hypertensive; and unmedicated hypertensive. Heritability was significantly lower among unmedicated hypertensives compared to medicated hypertensives and non-hypertensives for visual-spatial ability (p = 0.013) and episodic memory (p = 0.004). There were no heritability differences between non-hypertensives and medicated hypertensives. In addition, there were no significant differences in mean level cognition across the three blood pressure groups. These results suggest that in middle-aged men, untreated hypertension suppresses normal genetic influences on individual differences in certain domains of cognition prior to the emergence of hypertension-related effects on cognitive performance. These results further suggest that antihypertensive medication may protect against or reverse this effect.

Evidencia científica en el tratamiento de la hipertensión arterial crónica en la prevención del ictus

Hypertension represents a relative risk of stroke up to 5 times. It is associated to ischaemic and haemorrhagic stroke. Hypertension produces an increase in brain vessels resistance and loss of the physiological mechanism of autoregulation, and it can be measured with transcranial doppler. Clinical trials have established that reducing blood pressure is effective in primary prevention of ischaemic and haemorrhagic stroke in hypertensive patients and in secondary prevention in hypertensive and non-hypertensive patients, even with small reductions in blood pressure. There is no evidence of superiority of a definite drug, although drugs that have proven efficacy in clinical trials are recommended in clinical practice.

Relationship Between Blood Pressure and Stroke Risk in Patients With Symptomatic Carotid Occlusive Disease

Background and Purpose— Blood pressure lowering in patients with a previous transient ischemic attack (TIA) or stroke reduces the risk of recurrent stroke and coronary vascular events. However, there is uncertainty about the risks and benefits in patients with severe carotid occlusive disease, particularly those with a carotid occlusion or bilateral ≥70% carotid stenosis in whom cerebral perfusion is often impaired and may depend directly on systemic blood pressure. Therefore, we studied the effect of carotid artery disease on the relationship between blood pressure and stroke risk in patients with recent TIA or stroke.

Methods— We compared the relationship between blood pressure (systolic and diastolic blood pressures, pulse pressure) and stroke risk in TIA and stroke patients with documented stenosis of at least 1 carotid artery [European Carotid Surgery Trial (ECST) and North American Symptomatic Carotid Endarterectomy Trial (NASCET)] with that in TIA and stroke patients with a low prevalence of carotid disease [United Kingdom Transient Ischaemic Attack (UK-TIA) Aspirin Trial]. In ECST and NASCET, we also determined the relationship between blood pressure and stroke risk in patients with unilateral carotid occlusion and patients with bilateral ≥70% carotid stenosis.

Results— Stroke risk on medical treatment increased with blood pressure in ECST and NASCET, but the relationships were less steep than in the UK-TIA trial. The relationship between blood pressure and stroke risk was not affected by the presence of a unilateral carotid occlusion but was significantly affected by the presence of bilateral carotid stenosis ≥70% (interaction: systolic blood pressure, P =0.002; diastolic blood pressure, P =0.03; pulse pressure, P =0.003). In this group, the relationship was inverted because of the high stroke risks at lower blood pressures. This interaction was not present after carotid endarterectomy and was not present for the risk of myocardial infarction.

Conclusions— The risk of stroke increases with blood pressure in the great majority of patients with symptomatic carotid artery disease, but the relationship is less steep than in other patients with TIA or stroke. The relationship is unaffected by unilateral carotid occlusion alone but is inverted in patients with bilateral ≥70% carotid stenosis, suggesting that aggressive blood pressure lowering may not be advisable in this group. These patients represent only a few percent of all patients with TIA or stroke but have a high risk of recurrent stroke.

Cerebrospinal fluid cytoskeleton proteins in patients with subcortical white-matter dementia

The cerebrospinal fluid (CSF) levels of two cytoskeleton proteins, tau and the light subunit of neurofilament protein (NFL), both considered to reflect cerebral white-matter components, were investigated in a group of patients with a subtype of vascular dementia called 'subcortical white-matter dementia' (SWD). The group consisted of 25 demented patients with frontosubcortical brain syndromes, white-matter changes on computed tomography or magnetic resonance imaging and vascular disease or pronounced vascular risk factors. CSF-NFL was increased, whereas CSF-tau was normal, suggesting a differential involvement of the cytoskeleton in this patient group. The albumin ratio and the apolipoproteinE4 (ApoE4) allele status were also investigated. The albumin ratio was increased, indicating damage to the vessel walls with breakdown of the blood-brain barrier. No relationship was found between ApoE4 alleles and CSF levels of tau or NFL in this patient group. Besides presenting original data, the disease status of SWD is also discussed.