Risk Stratification Ontario Cardiac Rehabilitation Pilot Project.

Risk StratificationRisk Stratification

Ontario Cardiac Rehabilitation Pilot Project

Recommendation: CACR Recommendation: CACR

“ …programs consistently use some form of risk stratification for all their patients entering cardiac rehabilitation…”

Why risk stratify?Why risk stratify?

Ensure safety of the patientIdentify patient’s prognosis and

progression variables – direct intervention

Assess long term outcomesAssist in allocation of resources

Risk Stratification GuidelinesRisk Stratification Guidelines

AACVPRACCACPAHACACRDuke treadmill score

AACVPR GuidelinesAACVPR Guidelines

Guidelines for Cardiac Rehabilitation and Secondary Prevention Programs, AACVPR, Human Kinetics, 1999

Low Moderate High Functional Capacity

>7 METs < 5 METs

LVEF >50% 40-49% <40%

History Uncomplicated

MI, CABG, PTCA, no CHF

CA survivor, cardiogenic shock post MI or CABG, CHF, post procedure ischemia

Signs or symptoms

Assymptomatic Signs, symptoms

5-6.9 METs Signs, symptoms <5 METs

Dysrhythmia Nil

Complex ventricular arrhythmias, rest or exercise

Hemodynamics Normal with exercise

Abnormal with exercise

Depression Nil Clinically significant depression

CACR GuidelinesCACR Guidelines

Prognosis score (short-term absolute risk)– GXT: functional capacity– Ischemia, CCS class or max ST depression– LVEF– Dysrhythmias

Heart hazard score (long-term absolute risk)– Smoking– Lipids– BP– Diabetes– Psychological distress

Absolute vs. relative riskAbsolute vs. relative risk

Absolute: probability of suffering an acute CVD related event within a finite time period – Short-term (<5-10yrs)– Long-term (>10 yrs)

Relative: ratio between two levels of absolute riskIndividual’s absolute risk

Absolute risk of low-risk reference population

Short-term Absolute RiskShort-term Absolute Risk

< 5 yr risk of future cardiac eventLinked to prognostic variablesAssist in:

– optimizing safety of exercise – allocating resources

Short Term Absolute RiskShort Term Absolute Risk

Functional Capacity (METs)

Score Pt’s Score

> 12 0

> 10 1

> 9 2

> 8 3

> 7 5

> 6 7

< 6 10

Short Term Absolute RiskShort Term Absolute Risk

LVEF (%) Score Pt’s Score

> 55 0

45 - 54 3

36 - 44 7

< 35 15

Short Term Absolute RiskShort Term Absolute RiskIschemic Burden: use one of following

Score Pt’s Score

History CCS Class I 0

CCS class II 3

CCS class III 5

CCS class IV 7

ST dep. @ MaxHR None 0

1 mm 3

1- 2 mm 7

> 2 mm 10

Myocardial Perfusion None 0

Mild-mod, 1 vessel 3

Mod, multivessel 7

Severe, single-multi 15

Short Term Absolute RiskShort Term Absolute Risk

Dysrhythmias Score Pt’s Score

None 0

Atrial 2

Isolated PVC, <10/hr 3

Isolated PVC, >10/hr 6

Nonsustained VT 8

Recurrent VT 15

Hx VF MI < 6hr 6

MI > 6hr 15

No MI with ischemia 15

No MI no ischemia 12

Short Term Absolute RiskShort Term Absolute Risk

Sum of:Functional capacity scoreLVEF scoreIschemic burden scoreDysrhythmia score

Long Term Absolute RiskLong Term Absolute Risk

Risk of disease progressionIncreasing number of points reflects

increasing ‘exposure’ of heart hazard10 year absolute risk of CVD

development/progressionOnly traditional risk factors

Disease Progression RiskDisease Progression RiskHeart Hazard Women Men Pt’s score

Age, yrs

< 34 - 9 - 1

35 – 39 - 4 0

40 – 44 0 1

45 – 49 3 2

50 – 54 6 3

55 – 59 7 4

60 – 64 8 5

65 – 69 9 6

70 – 74 10 7

> 75 15 10

Disease Progression RiskDisease Progression RiskHeart Hazard: Cholesterol Women Men Pt’s scoreTotal: <4.14 mmol/L -3 -2

4.15-5.17 0 0

5.18-6.21 1 1

6.22-7.24 2 2

>7.25 3 3

LDL: <2.59 mmol/L -2 -1

2.60-3.36 0 0

3.37-4.14 1 1

4.15-4.92 3 2

>4.93 5 3

HDL: <0.9 mmol/L 5 2

0.91-1.16 2 1

1.17-1.29 1 0

1.30-1.55 0 -1

>1.56 -3 -2

Disease Progression RiskDisease Progression RiskHeart Hazard: BP (mmHg) Women Men Pt’s score

Systolic

<120 -3 0

120-129 0 0

130-139 1 1

140-159 2 2

>160 3 3

Diastolic

<80 0 0

80-84 0 0

85-89 1 1

90-99 2 2

>100 3 3

Disease Progression RiskDisease Progression Risk

Heart Hazard Women Men Pt’s score

Diabetes

Yes 6 4

No 0 0

Psychological distress

Yes 4 4

No 0 0

Smoking

Yes 4 4

No 0 0

Long Term Absolute RiskLong Term Absolute Risk

Sum of: Age score Lipid (TC, LDL, HDL) score BP score Diabetes score Psychosocial distress score Smoking score

Women = sum of scores x 1.5Men = sum of scores x 1.4

CACR Guidelines: Overall RiskCACR Guidelines: Overall Risk

Low - Moderate

High Very High

Risk of Disease Progression < 7 7-14 >14

Risk of Acute Cardiac Event <7 7-14 >14

Total <14 14-28 >28

Canadian Guidelines for Cardiac Rehabilitation & CVD Prevention, CACR, 1999

Use of Risk Stratification ScoresUse of Risk Stratification Scores

Low S/T & L/T risk Minimal or no intervention

Low S/T, high L/T riskHome or unsupervised

programs & heart hazard modification

High S/T & L/T risk Supervised exercise & structured heart hazard

modification

Clinical ApplicationClinical Application

High or very high short term risk:

Supervised exercise Consider ECG

monitoring Higher degree of

supervision May need to hold

exercise until further investigation

Satellite sites: refer to coordinating centre

High or very high long term risk:

Structured approach to heart hazard modification

Educational tool for patients

Case Study #1Case Study #1

Medical History IWMI May 2000 Cath: LM, LAD, Cx

normal; RCA 100% distally; LVEF 76%

PTCA/stent RCA, 100% to 0

GXT: 8.3 METs, no angina, no ST changes, no arrhythmias

Heart Hazards 63 yrs., male BP: 130/78 BMI: 28.2 Girth: 98 cm Physical activity: 75

min/week TC 4.8, LDL 2.7, HDL

1.12, Tg 2.25, FBG 4.8 D/c smoking x 25 yrs

Case Study #1: S/T RiskCase Study #1: S/T Risk

Variable Pt’s Results Range Pt’s Score

FC (METs) 8.3 >8 3

LVEF 76% >55 0

Ischemic Burden

No ST depression

No ST depression

0

Dysrhythmias None None 0

Total 3 = low-mod

Case Study #1: L/T RiskCase Study #1: L/T Risk

Heart Hazard Pt’s value Range Pt’s score (M)

Age 63 60 - 64 5

T-Chol 4.8 4.15 – 5.17 0

LDL-C 2.7 2.60 – 3.36 0

HDL-C 1.12 0.91 – 1.16 1

SBP 130 130 –139 1

DBP 78 <80 0

Diabetes No No 0

Psychological distress

HADS n/a, none

No o

Smoking D/C 25 yrs No 0

Total 7 X 1.4=9.8 = high

Case Study # 1Case Study # 1

Low-Mod S/T risk High L/T risk Total = 12.8, low-mod overall risk Cardiac rehab program:

– Home exercise program: 200-400 min/wk, resistance training

– Nutrition counselling: weight control, dyslipidemia

– Pharmacotherapeutic intervention: Baycol

Case Study #1: OutcomesCase Study #1: Outcomes

Clinical variable Intake score Exit score

Smoking No No

BP 130/78 120/72

Physical activity 75 min/wk 305 min/wk

BMI 28.2 27.6

Waist, girth 98 92

T-chol 4.8 3.5

LDL-C 2.7 1.8

HDL-C 1.12 1.17

Triglycerides 2.25 1.26

Glucose 4.8 4.1

FC (METs) 8.3 8.8

CACR Risk score 12.1-low-mod 5.6 – low-moderate

Case Study #2Case Study #2

Medical History IWMI 1992, PTCA RCA PTCA RCA x 2 1993 Recurrent angina 2000,

cath: LAD 70%, Cx 100%, RCA 95/90%, LVEF 34%

PTCA/stent RCA mid and distal

GXT: 6.1 METs, ST depression to 3 mm, assymptomatic, frequent PVCs & couplets

Heart Hazards 71 yr old male D/C smoking x 35 yrs BP 168/68 No regular exercise BMI 27.5, girth 103 cm TC 4.3, LDL 1.7, HDL 1.3,

Tg 2.77, FBG 5.6

Case Study #2: S/T RiskCase Study #2: S/T Risk

Variable Pt’s Results Range Pt’s Score

FC (METs) 6.1 >6 7

LVEF 34% <35 15

Ischemic Burden

3 mm ST depression

>2mm 10

Dysrhythmias Freq PVC PVC>10/hr 6

Total 38 = very high

Case Study #2: L/T RiskCase Study #2: L/T Risk

Heart Hazard Pt’s value Range Pt’s score (M)

Age 71 70 – 74 7

T-Chol 4.3 4.15 – 5.17 0

LDL-C 1.7 <2.59 -1

HDL-C 1.3 1.30 – 1.55 -1

SBP 168 >160 3

DBP 68 <80 0

Diabetes No No 0

Psychological distress

HADS n/a, none

No o

Smoking D/C 35 yrs No 0

Total 8 X 1.4=11.2 = high

Case Study #2:Case Study #2:

Very high S/T risk High L/T risk Total = 49.2, very high overall risk Cardiac rehab program:

– Referred back to cardiologist, exercise initially on hold, now returned to supervised exercise, ExRx below ischemia, telemetry monitoring, booked for CABG July 2001.

– BP monitored, multiple therapy