Differences in Vascular Risk Factors Between Etiological Subtypes of Ischemic Stroke

Abstract

Background-To understand the mechanisms of stroke and to target prevention, we need to know how risk factors differ between etiological subtypes. Hospital-based studies may be biased because not all stroke patients are admitted. If risk factors differ between patients who are admitted and those who are not, then case-control studies will be biased. If the likelihood of admission also depends on stroke subtype, then case-case comparisons may also be biased. Methods-We compared risk factors and ischemic stroke subtypes (TOAST classification) in hospitalized and nonhospitalized patients in 2 population-based stroke incidence studies: the Oxford Vascular Study (OXVASC) and Oxfordshire Community Stroke Project (OCSP). We also performed a meta-analysis of risk factor-stroke subtype associations with other published population-based studies. Results-In OXVASC and OCSP, stroke subtypes differed between hospitalized (293 of 647) and nonhospitalized patients (PϽ0.0001), with more cardioembolic strokes (odds ratio [OR], 1.8; 95% CI, 1.3 to 2.6) and fewer lacunar strokes (OR, 0.4; 95% CI, 0.3 to 0.7). Premorbid blood pressure and cholesterol were higher in hospitalized patients (both PϽ0.0001). Risk factor-stroke subtype associations in hospitalized patients were consequently biased (Pϭ0.001). Meta-analysis of data from all patients in OXVASC, OCSP, and 2 other studies demonstrated consistent risk factor-stroke subtype associations. However, contrary to previous hospital-based studies, there was only a weak (OR, 1.4; 95% CI, 1.1 to 1.8) and inconsistent (P heterogeneity ϭ0.01) association between small-vessel stroke and hypertension and no association with diabetes (OR, 1.0; 95% CI, 0.7 to 1.3). Conclusions-Prevalences of risk factors and stroke subtypes differ between hospitalized and nonhospitalized patients with ischemic stroke, which may bias hospital-based risk factor studies. Meta-analysis of population-based studies suggests that vascular risk factors differ between stroke subtypes.

Risk factors associated with ischemic heart disease occurence in acute ischemic stroke patients

“…In this meta-analysis only the cardioembolic subtype of IS showed an association with atherosclerosis. In the Erlangen study 23 , AH even showed a 22,23 . Thus the relation between AH and ischemic stroke is much weaker, than it is in IHD.…”

“…Schultz and Rothwell 22 showed in their meta-analysis of two population based stroke incidence studies involving more than 196000 patients, that vascular risk factors differ between the IS subtypes. In this meta-analysis, AH was surprisingly associated only with small vessel disease subtype of IS and not even with the atherosclerotic type.…”

Holter Monitoring and Loop Recorders: From Research to Clinical Practice

“…22 In 20-40 % of patients, the cause of ischaemic stroke cannot be determined after a complete diagnostic evaluation including ambulatory Holter monitoring for 24 hours or longer. [23][24][25][26][27] Two multicentre randomised controlled trials tested the hypothesis An observational study on 60 patients with cryptogenic stroke showed that ILRs might have a higher diagnostic yield than ambulatory Holter monitoring lasting 7 days. 28 This finding is consistent with results from the CRYSTAL AF trial, in which the mean time between randomisation and the first episode of AF was longer than a week (38 ± 28 days).…”

Odyssey of Patent Foramen Ovale: Closure in Cryptogenic Stroke: The Canary in the Coal Mine of Clinical Trials?

“…They may be more common in younger patients,1 in whom traditional stroke and atherosclerotic risk factors are less common, although there is no particular age cutoff above or below which cryptogenic stroke cannot be diagnosed. As a result, estimated stroke recurrence rates of 1.6% at 7 days, 4.2% at 30 days, 5.6% at 90 days, 14% to 20% at 2 years, and 33% at 5 years may be particularly devastating given the large number of patient‐years at risk for the young 1…”

“…In addition, as a group, these trials suffered from a number of problems that affected their ability to distinguish the impact of medical versus device therapy. First, expected rates of recurrence after cryptogenic stroke used to design these studies were based largely on population/epidemiologic studies from the 1990s and early 2000s 1. In the interim, technological improvements in neuroimaging (diffusion weighted magnetic resonance imaging, computed tomography angiography) and adoption of prolonged ECG monitoring and echocardiography into the workup for stroke7 likely increased the sensitivity of stroke diagnosis and the likelihood of identifying stroke etiology.…”