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A high coronary calcium burden may adversely affect the image quality of contrast-enhanced CT coronary angiography (CTCA), however the impact on diagnostic accuracy and overall utility of CTCA in this setting is controversial. We sought to assess the clinical outcome, coronary intervention rate and concordance of CTCA with alternative imaging modalities in the setting of an elevated calcium score.
We examined CTCA examinations performed at our institution with a calcium score of >600 and analyzed interpretability and findings. Scans were performed with a 320 detector-row CT scanner. Utilizing a search of death notices, structured patient interview and medical records review, downstream investigations, cardiovascular events, revascularization and mortality were recorded.
60 patients with a calcium score >600 had CTCA performed on the same day. CTCA findings were: Mild disease 28% Moderate 33%, Severe disease 32%, Non-diagnostic: 7%. During the period of follow-up (median= 1.75 years), 31 (53%) of patients underwent further assessment for coronary disease, 8 patients (13%) underwent revascularization and there were 2 non-cardiovascular and 1 cardiovascular death. No patient with mild or moderate disease at CTCA had subsequently demonstrated ischemia, was deemed to require PCI or suffered cardiac mortality. Event-free survival of those with severe and mild/moderate disease at CTCA were significantly different (p<0.01). The negative predictive value of CTCA for subsequent PCI and all cause mortality was 97% (100% for cardiac mortality only). The positive predictive value of CTCA for revascularization or CV death was 42%.
In patients with an elevated coronary calcium score, a negative CTCA implies an excellent short-term outcome and appears to exclude clinically significant coronary disease. Although the false positive rate of CTCA in this population is high, in the majority of patients no further investigation is required irrespective of coronary calcium burden.
Poster Sessions, Expo North
Saturday, March 09, 2013, 3:45 p.m.-4:30 p.m.
Session Title: Imaging: CT/Multimodality III
Abstract Category: 20. Imaging: CT/Multimodality
Presentation Number: 1181-343
- 2013 American College of Cardiology Foundation