Prognostic Value of Stress Myocardial Single-photon-emission Computed Tomography in the Elderly
Table 2: Major Studies Evaluating the Prognostic Value of SPECT MPS in the Elderly Author
Patients Mean (n)
Steingart et al., 200223 Kawamura et al., 200318
Lima et al., 200324 Valeti et al., 200515
De Winter et al., 200522 Schinkel et al., 200525 Zafrir et al., 200520 Nagao et al., 200726
Hachamovitch et al., 20098
576 201
328 247 294 247 162 175
5,200
7.0 4.1
2.8 6.4 2.2 4.0 3.7 4.6
2.8 Event Type
Follow-up (years)
All-cause death, myocardial infarction Cardiac death, myocardial infarction, coronary revascularisation
Cardiac death, myocardial infarction Cardiac death
All-cause cardiac death
All-cause cardiac death, myocardial infarction Cardiac death, myocardial infarction Cardiac death, myocardial infarction, coronary revascularisation Cardiac death
SPECT MPS = single-photon-emission computed tomography myocardial perfusion scintigraphy.
Figure 3: Risk Classification of Patients ≥75 Years of Age Categorised by Duke Treadmill Score or Summed Stress Score
Duke treadmill score (ETT)
6% 26% 0.9
Figure 4: Risk-adjusted Survival Curves Free of Cardiac Death
1.0
Event Rate in
0.9 1.1
1.1 0.8 0.8 2.5 3.2 1.5
1.3
Event Rate in
Low-risk Group High-risk Group (%/year )
(%/year) 6.1 4.5
3.0 5.8 1.9
10.1 14.5 6.8
5.9
0.8
68%
Summed stress score (EX-Tl SPECT)
35% 49%
In patients with normal (Nl) stress perfusion and gated ejection fraction (EF); abnormal (Abnl) stress perfusion and normal EF; normal stress perfusion and abnormal EF; and abnormal stress perfusion and EF. Differences across survival curves were significant (p
16% Low-risk Intermediate-risk High-risk
ETT = exercise treadmill test; Ex-Tl 201 SPECT = exercise thallium-201 single-photon- emission computed tomography. Source: Valeti et al., 2005.15
MPS-derived prognostic variable was the presence of perfusion defects in more than two coronary vascular supply territories, which was suggestive of multivessel CAD.18
Studies conducted with SPECT
MPS demonstrated that elderly patients who performed a pharmacological stress test had higher hard event rates than those undergoing an exercise test.19
To partially explain these findings it EUROPEAN CARDIOLOGY
should be noted that the non-randomised prescription of a pharmacological stress test in patients unable to exercise may lead to the selection of a subgroup with worse prognosis. In the previously mentioned study from Hachamovitch et al., patients undergoing pharmacological stress testing were older and more frequently presented markers of increased cardiovascular risk (e.g.
prior
myocardial infarction or revascularisation, diabetes, hypertension, etc.) compared with patients in the exercise stress group.8
Less widely investigated is the value of stress MPS for the prognostic characterisation of very old patients (≥80 years of age) with known or suspected CAD. The use of pharmacological stress testing is particularly frequent in this type of population with common difficulties with exercise. Zafrir et al. studied an octogenarian population (mean age 83 years) evaluated by exercise (29%) or dypiridamole (71%) stress MPS, confirming that event-free survival was significantly lower in patients with an abnormal scan than in those with a normal scan.20
These data 51
0.7 0 400
Nl perfusion + NI EF Abnl perfusion + NI EF
800 Time (days)
Nl perfusion + low EF Abnl perfusion + low EF
1,200 1,600
Survival
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