Risk Stratification
Ontario Cardiac Rehabilitation Pilot Project
Recommendation: CACR
“ …programs consistently use some
form of risk stratification for all their
patients entering cardiac
rehabilitation…”
Why risk stratify?
Ensure safety of the patient
 Identify patient’s prognosis and
progression variables – direct
intervention
 Assess long term outcomes
 Assist in allocation of resources

Risk Stratification Guidelines
AACVPR
 ACC
 ACP
 AHA
 CACR
 Duke treadmill score

AACVPR Guidelines
Low
Functional
Capacity
LVEF
History
Signs or
symptoms
Dysrhythmia
Hemodynamics
Depression
Moderate
< 5 METs
>7 METs
>50%
Uncomplicated
MI, CABG, PTCA,
no CHF
Assymptomatic
Nil
Normal with
exercise
Nil
High
40-49%
<40%
CA survivor, cardiogenic
shock post MI or CABG,
CHF, post procedure
ischemia
Signs, symptoms Signs, symptoms <5
METs
5-6.9 METs
Complex ventricular
arrhythmias, rest or
exercise
Abnormal with exercise
Clinically significant
depression
Guidelines for Cardiac Rehabilitation and Secondary Prevention Programs, AACVPR,
Human Kinetics, 1999
CACR 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 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 risk
Individual’s absolute risk
Absolute risk of low-risk reference population
Short-term Absolute Risk
< 5 yr risk of future cardiac event
 Linked to prognostic variables
 Assist in:

– optimizing safety of exercise
– allocating resources
Short Term Absolute Risk
Functional
Capacity (METs)
Score
> 12
0
> 10
>9
>8
>7
>6
<6
1
2
3
5
7
10
Pt’s Score
Short Term Absolute Risk
LVEF (%)
> 55
45 - 54
Score
0
3
36 - 44
< 35
7
15
Pt’s Score
Short Term Absolute Risk
Ischemic Burden: use
one of following
History
ST dep. @ MaxHR
Myocardial Perfusion
Score
CCS Class I
0
CCS class II
3
CCS class III
5
CCS class IV
7
None
0
1 mm
3
1- 2 mm
7
> 2 mm
10
None
0
Mild-mod, 1 vessel
3
Mod, multivessel
7
Severe, single-multi
15
Pt’s Score
Short Term Absolute Risk
Dysrhythmias
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
Pt’s Score
Short Term Absolute Risk
Sum of:
 Functional capacity score
 LVEF score
 Ischemic burden score
 Dysrhythmia score
Long Term Absolute Risk
Risk of disease progression
 Increasing number of points reflects
increasing ‘exposure’ of heart hazard
 10 year absolute risk of CVD
development/progression
 Only traditional risk factors

Disease Progression Risk
Heart Hazard
Women
Men
< 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
Age, yrs
Pt’s score
Disease Progression Risk
Heart Hazard: Cholesterol
Total:
LDL:
HDL:
Women
Men
-3
-2
4.15-5.17
0
0
5.18-6.21
1
1
6.22-7.24
2
2
>7.25
3
3
-2
-1
2.60-3.36
0
0
3.37-4.14
1
1
4.15-4.92
3
2
>4.93
5
3
5
2
0.91-1.16
2
1
1.17-1.29
1
0
1.30-1.55
0
-1
>1.56
-3
-2
<4.14 mmol/L
<2.59 mmol/L
<0.9 mmol/L
Pt’s score
Disease Progression Risk
Heart Hazard: BP (mmHg)
Women
Men
<120
-3
0
120-129
0
0
130-139
1
1
140-159
2
2
>160
3
3
<80
0
0
80-84
0
0
85-89
1
1
90-99
2
2
>100
3
3
Systolic
Diastolic
Pt’s score
Disease Progression Risk
Heart Hazard
Women
Men
Yes
6
4
No
0
0
Yes
4
4
No
0
0
Yes
4
4
No
0
0
Diabetes
Psychological distress
Smoking
Pt’s score
Long 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 1.5
Men = sum of scores x 1.4
CACR 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
<14
14-28
>28
Total
Canadian Guidelines for Cardiac Rehabilitation & CVD Prevention, CACR, 1999
Use of Risk Stratification Scores
Low S/T & L/T risk
Low S/T, high L/T risk
High S/T & L/T risk
Minimal or no intervention
Home or unsupervised
programs & heart hazard
modification
Supervised exercise &
structured heart hazard
modification
Clinical 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 #1
Medical History
Heart Hazards





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






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 Risk
Pt’s Results
Range
Pt’s Score
FC (METs)
8.3
>8
3
LVEF
76%
>55
0
No ST
depression
None
No ST
depression
None
0
Variable
Ischemic
Burden
Dysrhythmias
Total
0
3 = low-mod
Case Study #1: L/T Risk
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
Heart Hazard
Total
7 X 1.4=9.8 = high
Case 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: Outcomes
Clinical variable
Intake score
Exit score
No
No
130/78
120/72
75 min/wk
305 min/wk
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
12.1-low-mod
5.6 – low-moderate
Smoking
BP
Physical activity
BMI
CACR Risk score
Case 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 Risk
Pt’s Results
Range
Pt’s Score
FC (METs)
6.1
>6
7
LVEF
34%
<35
15
3 mm ST
depression
Freq PVC
>2mm
10
PVC>10/hr
6
Variable
Ischemic
Burden
Dysrhythmias
Total
38 = very high
Case Study #2: L/T Risk
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
Heart Hazard
Total
8 X 1.4=11.2 = high
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