12-phase flow (12)

1. 1FRAME
   Confirm scope: chronic cognitive impairment attributable to cerebrovascular disease (VCI continuum — vascular MCI → vascular dementia) in an older adult; not acute confusion (delirium) or a primary neurodegenerative amnestic syndrome (NINDS-AIREN)
   inputs: age, cognitive_symptom_timeline
   advance: Chronic cognitive impairment with a plausible cerebrovascular basis established; acute/rapid course excluded or pivoted (NINDS-AIREN)
2. 2ENTRY
   Capture trigger: step-wise/fluctuating executive-predominant decline, post-stroke/TIA cognitive impairment under surveillance, high vascular-risk burden with cognitive + gait/continence change, or significant cerebrovascular burden on imaging (VASCOG)
   inputs: cognitive_symptom_timeline
   advance: Entry trigger documented with onset, tempo, and relationship to vascular events (VASCOG)
3. 3CONTEXT
   Informant history; ADL/IADL baseline; full cerebrovascular-event history (stroke/TIA topography, focal deficits, temporal link); complete vascular-risk profile (HTN/DM/AF/dyslipidemia/smoking/carotid/OSA); medication review (anticholinergic/sedative burden + antithrombotic/anticoagulant status); caregiver availability + decision-making capacity (AHA/ASA VCID)
   inputs: informant_history, functional_status_adl_iadl, cerebrovascular_event_history, vascular_risk_factors, current_meds, caregiver_and_capacity
   actions: workup.cga, workup.beers_screen
   advance: Informant-corroborated functional baseline, cerebrovascular-event timeline, and modifiable-risk profile established (AHA/ASA VCID)
4. 4RED_FLAGS
   Acute new focal deficit / suspected acute stroke (route to acute stroke pathway — not this engine), rapidly progressive (<1-2y → CJD/autoimmune/paraneoplastic), NPH triad (gait + urinary incontinence + cognition — potentially reversible), superimposed delirium (acute fluctuating inattention), and young/familial pattern (CADASIL/hereditary small-vessel) (NINDS-AIREN; AHA/ASA VCID)
   inputs: cognitive_symptom_timeline, gait_continence_pseudobulbar
   actions: workup.acute_stroke, workup.delirium
   advance: No red flag, or red flag pivots case to the appropriate pathway (acute stroke / rapid-dementia / NPH evaluation / delirium / hereditary workup) (NINDS-AIREN)
5. 5INITIAL_WORKUP
   Executive-weighted objective cognitive testing (MoCA preferred over MMSE for subcortical/executive deficits) + functional assessment; depression screen (GDS-15); anticholinergic burden (ACB); reversible-cause labs B12/TSH + CMP/CBC; vascular-risk labs HbA1c + lipid panel; structural brain MRI to grade infarcts/lacunes/white-matter hyperintensities (Fazekas)/microbleeds/atrophy and confirm temporal/topographic link (NINDS-AIREN; VASCOG)
   inputs: depression_screen, b12, tsh, hba1c, lipid_panel, structural_brain_mri, functional_status_adl_iadl
   actions: workup.dementia, calc.moca, calc.gds_15, calc.acb_scale, panel.metabolic, panel.cmp, panel.cbc, panel.tsh
   advance: Executive-weighted cognitive/functional profile quantified; reversible/contributing causes excluded or treated; MRI cerebrovascular burden graded with temporal/topographic link assessed (NINDS-AIREN)
6. 6BRANCHING_WORKUP
   Etiology and source workup: carotid duplex / CTA-MRA for large-artery disease, ECG/Holter/extended monitoring for AF, echocardiography for cardioembolic source, vascular-risk completion; mixed-dementia assessment with AD biomarkers (amyloid PET / CSF Aβ42:40 + p-tau / plasma p-tau217) when an amnestic/insidious component coexists; NOTCH3 genetics + skin biopsy if CADASIL suspected; targeted rapid-dementia workup if course is rapid (NINDS-AIREN; AHA/ASA VCID)
   inputs: cerebrovascular_event_history, cognitive_domain_pattern
   advance: Stroke etiology classified (large-artery / cardioembolic / small-vessel / other), mixed-AD contribution resolved, and hereditary/rapid workup launched if indicated (NINDS-AIREN)
7. 7DIFFERENTIAL
   Vascular dementia subtype assignment (post-stroke/multi-infarct, strategic single-infarct, subcortical small-vessel/Binswanger, mixed AD+vascular [common], hereditary CADASIL, post-hemorrhage) vs Alzheimer disease (insidious amnestic, no infarct burden), DLB (early visual hallucinations/parkinsonism/RBD/fluctuation), FTD (early behavioral/language, younger), NPH (gait+incontinence+cognition triad, reversible), pseudodementia (vascular/post-stroke depression), reversible (B12/TSH/meds), delirium (acute fluctuating inattention) (VASCOG)
   inputs: cognitive_domain_pattern, cerebrovascular_event_history
   advance: Most-likely VaD subtype (or mixed/alternative diagnosis) assigned with phenotype + imaging support; siblings differentiated (VASCOG)
8. 8RISK_STRATIFICATION
   Stage severity — vascular MCI vs mild vs moderate vs severe via functional (CDR/FAST proxy) + executive-weighted MoCA trajectory; quantify residual recurrent-stroke risk and modifiable-risk gap (BP, LDL, HbA1c, AF anticoagulation status, carotid stenosis, smoking); anticholinergic cognitive burden (ACB) as a reversible contributor (AHA/ASA VCID)
   inputs: functional_status_adl_iadl, vascular_risk_factors
   actions: calc.moca, calc.acb_scale
   advance: Stage assigned; residual vascular-event risk and modifiable-risk gap quantified to drive intensity of secondary prevention (AHA/ASA VCID)
9. 9TREATMENT
   Cornerstone is AGGRESSIVE SECONDARY VASCULAR PREVENTION to slow progression (BP control to guideline target, etiology-appropriate antithrombotic, high-intensity statin, glycemic + lipid optimization, smoking cessation, AF anticoagulation per CHA2DS2-VASc, carotid revascularization evaluation, exercise/diet/weight); cholinesterase inhibitor/memantine only as a modest/uncertain-benefit option (consider chiefly if mixed AD pathology — NOT a strong recommendation); treat post-stroke/vascular depression, pseudobulbar affect (dextromethorphan-quinidine), and apathy; non-pharm + caregiver education/respite + ACP/capacity/driving as in dementia generally; BPSD — trigger search + non-pharm FIRST then time-limited low-dose antipsychotic for severe danger (boxed mortality; AVOID if Lewy features), avoid benzodiazepines; deprescribe anticholinergics/sedatives; rehab/PT-OT, falls + functional support; NPH shunt-evaluation referral if triad present (AHA/ASA VCID; VASCOG)
   inputs: vascular_risk_factors, current_meds, cognitive_domain_pattern, caregiver_and_capacity
   advance: Aggressive secondary-prevention bundle initiated to modifiable-risk targets; non-pharm/caregiver/ACP cornerstone in place; depression/PBA/apathy and BPSD pathways and rehab/falls support addressed (AHA/ASA VCID)
10. 10DISPOSITION
    Predominantly outpatient with stroke-prevention/neurology/geriatrics co-management and rehab (PT/OT/SLP); inpatient for acute stroke/TIA superimposed, superimposed delirium, BPSD crisis with danger, or caregiver breakdown; NPH neurosurgical referral if triad; long-term-care planning in advanced disease (AHA/ASA VCID)
    inputs: caregiver_and_capacity
    advance: Care setting and multidisciplinary referrals (stroke prevention clinic, rehab, social work, caregiver support) confirmed (AHA/ASA VCID)
11. 11MONITORING
    Vascular-risk target surveillance (BP, LDL, HbA1c, antithrombotic/anticoagulation adherence, smoking status) at each visit; cognitive/functional re-assessment (executive-weighted MoCA + ADL/IADL) every 6-12 months and after any new vascular event (watch for step-wise drops); recurrent stroke/TIA vigilance; ChEI tolerability (GI, bradycardia/syncope) if a trial is used; caregiver burden screening at each visit; deprescribing follow-through (AHA/ASA VCID)
    inputs: functional_status_adl_iadl, vascular_risk_factors, current_meds
    actions: calc.moca, calc.acb_scale
    advance: Monitoring cadence set; vascular-risk targets being met; no untreated recurrent event, intolerable ChEI ADR, or caregiver crisis (AHA/ASA VCID)
12. 12FOLLOWUP
    Reinforce and re-titrate secondary prevention at each visit (BP/LDL/HbA1c/anticoagulation/smoking); advance care planning revisited at each transition; driving/finances/capacity reviewed; caregiver respite and support referral; rehab continuity and falls prevention; palliative/end-of-life planning and ChEI/memantine deprescribing decision in advanced (severe) disease (VASCOG)
    inputs: caregiver_and_capacity
    advance: Secondary-prevention plan re-titrated to target; ACP documented; caregiver support arranged; next cognitive review and goals-of-care interval scheduled (VASCOG)