Post on 22-Dec-2015
transcript
Long-term predictive value of assessment of coronary atherosclerosis by contrast- enhanced
coronary computed tomography angiography: meta-analysis and systematic review
Department of Clinical Radiology, Ludwig-Maximilians University, Munich, Germany
Fabian Bamberg MD MPH
Background• CT technology has progressed rapidly resulting in robust
diagnostic accuracy for coronay plaque / stenosis detection
• Coronary CT angiography increasingly penetrates clinical practices
• Beyond diagnostic value: potential prognostic value for occurrence of cardiovascular events
• To date: Small sample size studies with limited evidence
• Important to appropriately design future outcome studies and consideration of the public health impact
RCA: No Plaque Proximal LAD:Presence of Plaque
RCA: Significant Stenosis
Examples of Cardiac CTA Findings
AimTo perform a systematic review of studies that assessed the prognostic value of coronary CT angiography findings on a combined cardiovascular endpoint and pooled available evidence in a meta-analysis
Methods I – Study selection• PubMed, EMBASE, and the Cochrane library through
January 2010• Medical Subject Heading: “cardiac/coronary CTA" in
combination with "mortality", or "survival analysis", or "outcome", or "death", or "prognosis/prognostic“
• Expert opinions• References of review articles
Methods II - Inclusion Criteria• Cohort studies (prospective or retrospective) of >100 subjects who
were followed for >1 year• ≥16-slice CT and electron-beam CT • Studies in patients with stable presentation, i.e. stable angina• Two independent investigators abstracted information on:
– Population– Technical equipment– Study quality: endpoint committee, blinded CT results and outcome
assessment, exclusion of subjects after enrollment, and endpoint definition)
– CT predictors studies and associated HR
• Discordancy solved by consensus
Methods III - Statistics• Primary objective: risk associated with significant coronary stenosis
(>50% luminal narrowing) and a combined CV endpoint • Secondary: Each stenosis, 3-VD, presence non-obstructive plaque• Between-study heterogeneity: Q-statistic and I2 statistic • Publication bias: funnel plots• Meta-regression: sources of heterogeneity
– Age, gender, BMI, Hx CAD– CT Technique– Type of endpoint (all-cause mortality vs. combined endpoint),– Study quality
Results – Study selection
Results – Study selection
• 7,335 subjects: 59.1±2.6 years, 62.8% male
• FU: 20.4 months (14 to 78)• 82% single-center design• 55% Europe or 36% US
• 100% suspected CAD • 18% additionally w/ known CAD
• 64% 64-slice CT technology• 18% 16-slice technology 18% EBCT
Results – Primary endpoint – sign. stenosis• 3,670 participants, FU 21.9 months• 252 (6.8%) outcome events (62% revascularizations)
Results – Primary Endpoint – sign. stenosis• Q-statistic: p<0.001• I2-test: 71.8% of the variability between-study heterogeneity• No sign of asymmetry of funnel plot (z=1.34, p=0.18)
Results - Meta-regression – primary endpointVariable Studies N events / N Hazard ratio (95% CI) P
Average age
>58 years*
≤58 years
4
5
126/1657
126/2013
19.83 (10.04 – 39.16)
7.17 (4.23 – 12.15)
0.02
Revasc. in Endpoint
Not included
Included
3
6
55/1241
197/2429
6.15 (3.22 – 11.74)
15.41 (8.92 – 26.62)
0.03
Study Quality
Higher
lower
5
4
106/2157
146/1513
16.83 (10.08 – 28.11)
5.86 (3.34 – 10.29)
0.001
No heterogeneity: proportion of males, obesity, history of CAD, CT technology used (64-slice vs. other), follow-up time, potential overfitting of the models
Secondary predictors
CT Angiography Finding Events HR* (95%-CI) I2 P Z P
LM Coronary Stenosis 142 6.64 (2.6 – 17.3) 71.9% 0<0.01 0.49 0.62
Per Coronary Stenosis 145 1.35 (1.1 – 1.7) 95.1% <0.01 0.41 0.52
3-Vessel disease 125 2.50 (1.9-3.3) 0% 0.55 0.32 0.87
Any Atherosclerotic Plaque 244 4.51 (2.2 – 9.4) 26.7% 0.33 0.96 0.32
Segment with any plaque 163 1.23 (1.17 – 1.29) 7.6% 0.35 -0.7 0.50
Segment with NCAP 124 1.29 (1.2 – 1.4) 0% 0.13 0.27 0.91
Heterogeneity due to revascularization in endpoints (both p<0.01) and higher prevalence of history of CAD (both p=0.05).
n
Summary• Coronary CT findings are strong predictors of CV events in
symptomatic subjects • Independent of coronary artery calcification and cardiovascular
risk factors• Choice of endpoints, classification of CT findings, and study
population introduced substantial heterogeneity• Basis to homogenize reporting standards for cardiac CT, to
determine appropriate design of prospective randomized trials, and to estimate the potential impact on health care systems