Clinical Cut-Offs & Results Interpretation Guide

Pulse Wave Velocity (PWV)

Variables: cfPWV (m/s), central BP

Cut-offs (ESC / AHA):

• <10 m/s – normal arterial compliance

• 10–12 m/s – borderline stiffness

• >12 m/s – elevated stiffness (CKD, LVH, vascular ageing)

• >14 m/s – high-risk phenotype

Why clinically useful:

• Predicts CV mortality better than brachial BP

• Identifies vascular ageing and CKD progression risk

• Important pre-operative risk marker

References: ESC Arterial Stiffness Consensus; AHA Vascular Function Statement.

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Augmentation Index (AIx / AIx@75)

Variables: Wave reflection magnitude, vascular compliance

Cut-offs:

• Men: <25% normal

• Women: <35% normal

• >40–45% – increased vascular load

• >50% – impaired buffering capacity

Why clinically useful:

• Predicts peri-operative BP instability

• Indicates endothelial dysfunction

• Sensitive to autonomic imbalance

References: AtCor Medical; London Arterial Studies.

Variables: VO₂peak, Anaerobic Threshold (AT), VE/VCO₂ slope, HRR

Cut-offs (ATS/ACSM):

VO₂peak (% predicted)

• 80% normal

• 60–80% mild impairment

• 40–60% moderate

• <40% severe (major surgical risk)

Anaerobic Threshold (AT)

• 11 mL/kg/min → low risk

• 8–11 → moderate risk

• <8 → high peri-operative risk

VE/VCO₂ slope

• <30 normal

• 30–36 moderate inefficiency

• 36 prognostic marker (HF, PH, CKD)

Why clinically useful:

• Best predictor of peri-operative mortality

• Essential for risk stratification before TEER, major orthopaedics, and cancer surgery

• Quantifies metabolic and ventilatory reserve

References: ATS/ACCP CPET Guidelines; ACSM; HF Consensus.

Variables: FEV₁, FVC, FEV₁/FVC ratio

Cut-offs (ATS/ERS):

• FEV₁ % predicted:

  • 80% normal

  • 70–79 mild

  • 60–69 moderate

  • 50–59 moderately severe

  • <50% severe

• FEV₁/FVC <0.70 → obstructive defect

Why clinically useful:

• Identifies airflow obstruction

• Provides objective baseline for anaesthesia and surgery

• Vital for TEER and major ortho pre-assessment

References: ATS/ERS Spirometry Standards.

Variables: 24-hour BP, dipping index, AASI, morning surge

AHA ABPM cut-offs:

• 24h avg <130/80

• Day <135/85

• Night <120/70

Dipping:

• Normal: 10–20%

• Non-dipper: <10%

• Reverse dipper: ↑ BP at night (major risk)

Morning Surge:

• 55 mmHg = stroke risk

AASI:

• <0.40 normal

• 0.40–0.50 borderline

• 0.50 arterial stiffness

Why clinically useful:

• Detects masked hypertension

• Predicts renal decline

• Strong predictor of stroke and MI

References: AHA 24-hour BP Guidelines; Kario MSURGE.

(Use age 70–85 normative tables)

Chair Stand (30s)

• ≥10 normal

• 8–9 mild frailty

• ≤7 frailty

8-Foot Up-and-Go

• ≤6 sec normal

• 7–9 mild

• ≥10 frailty

• ≥12 high fall risk

2-Minute Step Test

• ≥60 steps normal

• 40–59 moderate

• ≤39 frailty

Why clinically useful:

• Predicts surgical outcomes

• Predicts readmission risk

• Identifies mobility decline

References: Rikli & Jones Senior Fitness Test Manual.

Variables: static/dynamic balance, postural control

4-Stage Balance Test (CDC/WHO)

• Fail tandem ≥10 sec → impairment

• Single-leg <5 sec → fall risk

• Single-leg <2 sec → severe frailty

Why clinically useful:

• Predicts fall risk > 2 years

• Indicates vestibular/autonomic dysfunction

References: CDC STEADI; WHO Falls Guidelines.

Gait Speed (4 m)

• 0.8 m/s normal

• 0.6–0.8 pre-frail

• <0.6 frail

• <0.4 severe frailty

TUG

• <10 sec normal

• 20 frail

• 30 very high fall risk

Why clinically useful:

• Best single predictor of loss of independence

• Strong predictor of mortality in frail older adults

References: Fried Frailty Criteria; Podsiadlo & Richardson (1991).

HRV

• RMSSD <20 ms → parasympathetic withdrawal

• SDNN <30 ms → low autonomic resilience

• LF/HF >2.5 → sympathetic dominance

Orthostatic

• SBP drop ≥20 mmHg OR DBP ≥10 mmHg → OH

• HRV recovery >2 min → autonomic blunting

Why clinically useful:

• Predicts falls, syncope, peri-op instability

• Tracks autonomic neuropathy & recovery

References: Task Force on HRV (1996); autonomic dysfunction literature.