The effects of antiepileptic drugs on vascular risk factors: A narrative review

Impact of age on cerebrovascular dilation versus reactivity to hypercapnia

This study quantified the effect of age on cerebrovascular reactivity and cerebrovascular conductance while accounting for differences in grey matter volume in younger (YA: n = 12; 24 ± 4 years, six females) and older adults (OA: n = 10; 66 ± 7 years; five females). Cerebral blood flow velocity (CBFV; transcranial Doppler) in the middle cerebral artery (MCA), MCA cross-sectional area (CSA), intracranial volumes (magnetic resonance imaging), and mean arterial pressure (MAP; Finometer), were measured under normocapnic and hypercapnic (6% carbon dioxide) conditions. Cerebral blood flow (CBF) was quantified from CBFV and MCA CSA and normalized to grey matter volume. Grey matter volume was 719 ± 98 mL in YA and 622 ± 50 mL in OA (P = 0.009). Cerebrovascular reactivity (%ΔCBF/ΔP_ETCO₂) was not different between YA and OA. In contrast, cerebrovascular conductance (CBF/MAP) in response to hypercapnia was reduced in OA (P = 0.02). Of note, MAP increased more with hypercapnia in OA compared with YA. Therefore, the central hemodynamic response to hypercapnia compensated for a diminished dilatory response downstream from the MCA so that the CBF response to hypercapnia per unit of brain mass was not affected by age. This impairment was not detected by traditional measures of cerebrovascular reactivity.

The heart of epilepsy: Current views and future concepts

Cardiovascular (CV) comorbidities are common in people with epilepsy. Several mechanisms explain why these conditions tend to co-exist including causal associations, shared risk factors and those resulting from epilepsy or its treatment. Various arrhythmias occurring during and after seizures have been described. Ictal asystole is the most common cause. The converse phenomenon, arrhythmias causing seizures, appears extremely rare and has only been reported in children following cardioinihibitory syncope. Arrhythmias in epilepsy may not only result from seizure activity but also from a shared genetic susceptibility. Various cardiac and epilepsy genes could be implicated but firm evidence is still lacking. Several antiepileptic drugs (AEDs) triggering conduction abnormalities can also explain the co-existence of arrhythmias in epilepsy. Epidemiological studies have consistently shown that people with epilepsy have a higher prevalence of structural cardiac disease and a poorer CV risk profile than those without epilepsy. Shared CV risk factors, genetics and etiological factors can account for a significant part of the relationship between epilepsy and structural cardiac disease. Seizure activity may cause transient myocardial ischaemia and the Takotsubo syndrome. Additionally, certain AEDs may themselves negatively affect CV risk profile in epilepsy. Here we discuss the fascinating borderland of epilepsy and cardiovascular conditions. The review focuses on epidemiology, clinical presentations and possible mechanisms for shared pathophysiology. It concludes with a discussion of future developments and a call for validated screening instruments and guidelines aiding the early identification and treatment of CV comorbidity in epilepsy.

Poststroke epilepsy: update and future directions

Stroke is among the most common causes of epilepsy after middle age. Patients with poststroke epilepsy (PSE) differ in several respects from patients with other forms of structural-metabolic epilepsy; not least in age, age-related sensitivity to side effects of antiepileptic drugs (AEDs), and specific drug-drug interaction issues related to secondary-stroke prophylaxis. Encouragingly, there has lately been remarkable activity in the study of PSE. Three developments in PSE research deserve particular focus. First, large prospective trials have established the incidence and risk factors of PSE in the setting of modern stroke care. Stroke severity, cortical location, young age, and haemorrhage remain the most important risk factors. Second, although more studies are needed, epidemiological data indicate that the risk of PSE may be influenced, for instance, by statin treatment. Third, studies are emerging regarding the treatment and prognosis of PSE. Levetiracetam and lamotrigine may be well tolerated treatment options and seizure freedom is achieved in at least a similar proportion of patients as in other epilepsies. Furthermore, new animal models such as photothrombotic stroke gives hope of a more clear understanding of PSE epileptogenesis in the near future. In summary, PSE shows indications of maturing into an independent epilepsy research field. This review summarizes recent advances in our understanding of PSE and provides an update on management issues such as diagnosis, AED selection, and prognosis. Finally, future research challenges in the field are outlined.

Metabolic syndrome and anticonvulsants: A comparative study of valproic acid and carbamazepine

PURPOSE

The aim of this study was to compare the risk of metabolic syndrome (MS) and evaluate related factors for MS among people with epilepsy treated with valproate (VPA) or carbamazepine (CBZ).

METHODS

A total of 213 adult patients with epilepsy treated with VPA (n=118) or CBZ (n=95) monotherapy were included in the study. Participants were evaluated for the presence of MS, diagnosed according to the National Cholesterol Education Program Adult Treatment Panel III criteria.

RESULTS

In the multiple logistic regression analysis, the risk of MS in CBZ- and VPA-treated patients was similar (odds ratio [OR]=0.99; 95% confidence interval [CI], 0.43-2.26; P=0.979). A lower proportion of CBZ-treated patients had abnormally low levels of high-density lipoprotein cholesterol (OR=0.10; 95% CI, 0.02-0.42; P=0.002), whereas a lower proportion of VPA-treated patients had abnormally high concentrations of fasting blood glucose (OR=0.30; 95% CI, 0.13-0.69; P=0.004). Females treated with VPA tended to have a higher risk of MS (OR=1.48; 95% CI, 0.50-4.41; P=0.485) compared to males (OR=0.74; 95% CI, 0.28-1.96; P=0.551), although this difference was not statistically significant.

CONCLUSION

Although the overall risk of MS was similar in patients with epilepsy who were treated with VPA or CBZ, the distribution of MS components differed between treatment groups. Patients treated with CBZ or VPA less frequently had decreased high-density lipoprotein cholesterol levels or increased blood glucose concentrations, respectively. Females on VPA treatment could be at higher risk of MS than males.

Cardiac functions of voltage-gated Ca(2+) channels: role of the pharmacoresistant type (E-/R-Type) in cardiac modulation and putative implication in sudden unexpected death in epilepsy (SUDEP)

Voltage-gated Ca(2+) channels (VGCCs) are ubiquitous in excitable cells. These channels play key roles in many physiological events like cardiac regulation/pacemaker activity due to intracellular Ca(2+) transients. In the myocardium, the Cav1 subfamily (L-type: Cav1.2 and Cav1.3) is the main contributor to excitation-contraction coupling and/or pacemaking, whereas the Cav3 subfamily (T-type: Cav3.1 and Cav3.2) is important in rhythmically firing of the cardiac nodal cells. No established cardiac function has been attributed to the Cav2 family (E-/R-type: Cav2.3) despite accumulating evidence of cardiac dysregulation observed upon deletion of the Cav2.3 gene, the only member of this family so far detected in cardiomyocytes. In this review, we summarize the pathophysiological changes observed after ablation of the E-/R-type VGCC and propose a cardiac mechanism of action for this channel. Also, considering the role played by this channel in epilepsy and its reported sensitivity to antiepileptic drugs, a putative involvement of this channel in the cardiac mechanism of sudden unexpected death in epilepsy is also discussed.