Transcript Association between Traditional Risk Assessment and the

Usefulness of Coronary Computed Tomography
Angiography For Early Triage of Patients with
Acute Chest Pain - The Rule Out Myocardial
Infarction Using Computer Assisted Tomography
(ROMICAT) Trial
Udo Hoffmann, Fabian Bamberg, Claudia U. Chae, John H. Nichols,
Ian S. Rogers, Sujith K. Seneviratne, Quynh A. Truong, Ricardo C.
Cury, Suhny Abbara, Michael D. Shapiro, Jamaluddin Moloo, Javed
Butler, Maros Ferencik, Hang Lee, Ik-Kyung Jang, Blair A. Parry,
David F. Brown, James E. Udelson, Stephan Achenbach, Thomas J.
Brady, John T. Nagurney
Department of Radiology, Emergency Medicine, and Cardiology Division,
Massachusetts General Hospital and Harvard Medical School, Boston MA
Disclosures
Research Grants:
Siemens Medical Solutions, Amersham/GE
Healthcare, Bracco Diagnostics, NIH
Advisory Boards:
Vital Images, Bayer Healthcare/Siemens
Medical Solutions
Early Risk Stratification and Triage in the ED
- 6 Million present with chest pain to ED annually
- ECG, initial biomarkers, and clinical presentation and
traditional risk factors – no safe triage possible
(Nagurney, JAMA 2006)
- low threshold to admit, >80% have no ACS,
$8Billion annually healthcare cost
- 1-5% of missed ACS cause 20% of ED malpractice
costs
Improvement of the initial ED evaluation needed!
Preliminary coronary CTA Studies
- coronary MDCT is feasible in the acute care setting
- low to intermediate risk patients - absence of CAD
has 100% NPV for ACS – found in 40% of patients
Hoffmann et al Circulation 2006
- very low risk patients - CT may be cost saving
alternative to myocardial perfusion stress testing
Raff et al JACC 2007
- normal coronary CTA has excellent NPV for MACE
within 15 months
Rubinshtein et al. Circulation 2007
Remaining Questions for Patient Management
1. Confirmation in larger cohorts
2. Safety of Stenosis based Triage
3. Relevance of detected Stenosis
4. Incremental Value of non-calcified plaque
for exclusion of ACS
ROMICAT I - Specific Aims
1. Determine the prevalence of coronary
atherosclerotic plaque and stenosis in
patients with acute chest pain and low to
intermediate for ACS
2. Determine the diagnostic accuracy of
these findings for ACS
3. Determine whether this information is
incremental to current risk assessment
ROMICAT I – Study Design
Observational, double-blinded Cohort Study
Cardiac CT Analysis - blinded to caregiver
and subjects
1. Presence of atherosclerotic plaque per
coronary segment
a. Calcified plaque
b. Non-calcified plaque
Neg. ECG
Neg. Trop
2. Presence of significant coronary artery
stenosis (>50%)
Standard clinical care
Acute
Chest
Pain
ED
Index
Hospitalization
6 month FU
t
ROMICAT I - Methods
Inclusion Criteria
- >5 min of chest pain <24h
- Normal initial Biomarker
- Admitted to Rule out MI
- Normal sinus rhythm
Exclusion Criteria
-
positive initial Troponin
-
Diagnostic ECG changes
-
Creatinine >1.3 mg/dl
-
Known CAD
Coronary MDCT
- 64-slice MDCT (Siemens, Forchheim, Germany)
- Beta-Blocker if HR>65 bpm, Nitro
- ~20 ml + 80ml contrast agent (Iodhexodol 320)
- tube current: ~850 mAs, tube voltage: 120 kV
Primary Endpoint
ACS* (NSTEMI or UAP) during Index Hospitalization and MACE during 6month follow-up adjudicated by independent committee
*According to AHA/ACC/ESC Guidelines
18 month Screening and Enrollment
Protocol Eligible
Subjects (n = 658)
Enrolled Subjects (n =
412)
Study Population (n =
368)
• Physician Denied (n = 19)
• Patient Refusal (n = 124)
• Missed to Ongoing Recruitment (n =
103)
Incomplete Scan (n=17)
• Interference with Clinical Care (n = 10)
• Claustrophobia/Nausea (n = 3)
• Contrast Extravasation (n = 3)
• Scanner Malfunction (n = 1)
Complete Scan (n=27)
• History of Stent Placement (n = 10)
• History of CABG (n = 17)
ROMICAT I – Demographics and Risk Factors
Age (years, mean  SD)
52.7±12
Male Gender (n, %)
223 (61%)
Race (n, %)
African American
Caucasian
Asians
Others
31 (8%)
313 (85%)
4 (1%)
20 (6%)
No. of risk factors (median, IQR)
TIMI Score (low/intermediate/high) in %
ACS during index hospitalization (%, n)
Unstable angina pectoris (%, n)
Myocardial infarction (%, n)
MACE during six month follow- up (%, n):
Recurrent chest pain:
Outpatient evaluation (PCP)
Readmission without testing
Readmission with testing
2 (1)
94.3/ 5.4/ 0.3
31 (8%)
23 (74%)
8 (26%)
68
50
5
13
0
(18%)
(74%)
(7%)
(19%)
ROMICAT I – Prevalence of Plaque and Stenosis
CAD categories with relevance for early triage of
patients with ACP in the ED
Non-obstructive Plaque 31.2%
N= 115/368
Significant stenosis
detected or not excluded 18.4%
N= 68/368
No CAD - 50.4%
(no plaque and no
stenosis)
N= 185/368
ROMICAT I – CAD and ACS
No CAD
Nonobstructive Plaque
Significant stenosis
detected or not excluded
No ACS
7 ACS
• non-stenotic ACS
• small vessel disease
24 ACS
NSTEMI with significant stenosis
40-year old male who presented 3 hours after the
onset of substernal chest pain, inconclusive initial
evaluation in the ED, Troponin positive 8 hours after
ED presentation, underwent invasive coronary
angiography with stenting of an 80% mid LAD
NSTEMI without significant stenosis in CT
Subject
Coronary CTA Finding
of Non-obstructive
Plaque
Troponin
Stress Nuclear Perfusion
Imaging
Coronary
Angiography/
Intervention
Clinical
Outcome
76-year old prox RCA, prox LCX,
female
and prox and mid LAD
Negative
inferolateral area of ischemia
None
UAP
78-year old
Subject
female
Negative
Troponin
inferolateral area of ischemia
Stress Nuclear Perfusion
Imaging
apical area of ischemia,
hypokinesis inferolateral region
inferolateral area of ischemia
None
None
Coronary
Angiography/
None
Intervention
UAP
Clinical
Outcome
UAP
None
30% stenosis in mid
LAD/None
None
95% PLV,
50% 1st
septal branch/ stent
PLV
None
UAP
NSTEMI
40% D2 ostium,
70%
D3 ostium
30%
stenosis
in mid
stenosis/None
LAD/None
NSTEMI
NSTEMI
LM, prox, mid, and dist.
Coronary
CTA
Finding
LAD;
PDA
of Non-obstructive
Mid RCA
Plaque
72-year old
male
76-year old prox RCA, prox LCX,
52-year old
Mid LAD
female
and prox and mid LAD
male
78-year old LM, prox, mid, and dist.
63-year old Prox and mid RCA, mid
female
LAD; PDA
male
and dist. LAD
72-year old
Mid RCA
male
53-year old
LM and dist. LAD
male old
52-year
Mid LAD
male
Negative
Negative
2nd set pos.
(+6.8h)
Negative
3rd set pos.
(+5.7h)
Negative
2nd set pos.
2nd(+6.6h)
set pos.
(+6.8h)
inferolateral area of ischemia
None
apical area of ischemia,
hypokinesis inferolateral region
None
None
UAP
NSTEMI
UAP
59-year
63-year old
female
male
Prox and OM1
mid RCA, mid
and dist. LAD
rd
3Negative
set pos.
(+5.7h)
None
80%PLV,
PDA stenosis/
95%
50% 1st
stent
PDAstent
septal
branch/
PLV
UAP
NSTEMI
53-year old
male
LM and dist. LAD
2nd set pos.
(+6.6h)
None
40% D2 ostium,
70% D3 ostium
stenosis/None
NSTEMI
59-year old
female
OM1
Negative
None
80% PDA stenosis/
stent PDA
UAP
NSTEMI with small vessel disease
59-year old female with typical chest pain, nondiagnostic ECG and negative serial Troponin,
coronary CTA – plaque in OM 1, invasive coronary
angiography demonstrates 95% stenosis of the PDA
NSTEMI with PDA stenosis
ROMICAT I – Diagnostic Accuracy
1. Triage Criterion: Presence of any plaque
Plaque
No
Plaque
ACS
No
ACS
Sens: 100% (0.88-1.00)
31
154
NPV: 100% (0.98-1.00)
Spec: 54% (0.49-0.60)
0
183
PPV: 17% (0.12-0.23)
2. Triage Criterion: Presence of significant Stenosis (>50%)
ACS
No
ACS
Sens: 77% (0.59-0.90)
Sign.
Stenosis
24
44
NPV: 98% (0.95-0.99)
No
Stenosis
7
Spec: 87% (0.82-0.90)
293
PPV: 35% (0.24-0.48)
Results – Stenosis and ACS
• specificity of significant stenosis for ACS was lower
in subjects ≥65 years of age (58% vs. 91%) because
of increased prevalence of CAC (84% vs. 39%;
p<0.0001)
• in 34 patients a significant stenosis was detected
• 20 had ACS
• 14 had no ACS or MACE after 6 months
severe RCA lesion, no
regional LV
dysfunction, normal
stress SPECT study,
diagnosis of ‘non
cardiac chest pain’.
Incremental Value of coronary CTA to TIMI
AUC for the
detection of ACS
during index
hospitalization
Extent of plaque,
presence of
stenosis, TIMI risk
score (AUC: 0.88,
0.82 vs. 0.63;
respectively, all
p<0.0001).
Summary
- confirmation - Absence of any CAD in 50% of
patients - 100% NPV for ACS – may enable early safe
and early discharge from the ED
- triage criterion of 50% stenosis is not perfect
because of non-stenotic ACS and limited spatial
resolution of coronary CTA
- significant stenosis is detected in 10% of patients by
coronary CTA – about 40% of these were discharged
with a diagnosis of non-cardiac chest pain
- incremental value of non- calcified plaque for early
triage is limited
Thank you!
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