Ischemic Attack, TransientStrokeTiclopidineCerebrovascular DisordersPlatelet Aggregation InhibitorsCarotid StenosisEndarterectomy, CarotidAspirinRecurrenceCarotid Artery DiseasesCarotid Artery, InternalBrain IschemiaRisk FactorsProspective StudiesIntracranial Embolism and ThrombosisCerebral InfarctionIntracranial EmbolismFollow-Up StudiesTime FactorsCerebral AngiographyDipyridamoleTreatment OutcomeUltrasonography, Doppler, TranscranialMagnetic Resonance AngiographyAtrial FibrillationEchocardiography, TransesophagealRisk AssessmentCarotid ArteriesAnticoagulantsGreat BritainReferral and ConsultationPrognosisTomography, X-Ray ComputedRetrospective StudiesFibrinolytic AgentsSeverity of Illness IndexCerebrovascular CirculationPatient SelectionEnglandPredictive Value of TestsCohort StudiesAge FactorsIncidenceVertebrobasilar InsufficiencyEmbolismMyocardial IschemiaAcute DiseaseMyocardial InfarctionCardiovascular DiseasesMagnetic Resonance ImagingEndarterectomyMigraine DisordersIntracranial ArteriosclerosisIschemiaComplement Membrane Attack ComplexNeurologyAmaurosis FugaxIntracranial Arterial DiseasesMoyamoya DiseaseDouble-Blind MethodSecondary PreventionCalciumCerebral HemorrhageBrainDose-Response Relationship, DrugRiskCerebral ArteriesSulfinpyrazoneSeptember 11 Terrorist AttacksDrug Therapy, CombinationClinical Trials as TopicArterial Occlusive Diseases