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Oct200901

3

First Head-to-Head Comparison of Effective Radiation Dose from Low-Dose 64-Slice CT with Prospective ECG-Triggering versus Invasive Coronary Angiography

Heart. 2009; 95(20):1656-1661

B A Herzog, C A Wyss, L Husmann, O Gaemperli, I Valenta, V Treyer, U Landmesser and P A Kaufmann

OBJECTIVES: To compare effective radiation dose of low-dose 64-slice CTCA using prospective ECG-triggering versus diagnostic invasive coronary angiography (CA). Background: Reduction of radiation burden of multidetector computed tomography coronary angiography (CTCA) has remained an important task.

METHODS: 42 patients referred for elective invasive CA owing to suspected coronary artery disease (CAD) were prospectively enrolled to undergo a low-dose CTCA without calcium scoring within the same day before CA. Dose-area product of diagnostic invasive CA and dose-length product of CTCA were measured, converted into effective radiation dose and compared using Mann-Whitney U tests. In addition, accuracy of CTCA to detect CAD (coronary artery narrowing >50%) was assessed using invasive CA as standard of reference. On an intention-to-diagnose basis all non-evaluative vessels were included in the analysis and censored as positive.

RESTULTS: The estimated mean effective radiation dose was 8.5 (4.4) mSv (range 1.4–20.5 mSv) for diagnostic invasive CA, and 2.1 (0.7) mSv (range 1.0–3.3 mSv) for CTCA (p<0.001). 19 patients (42.9%) had no CAD by invasive CA. 40 (95.2%) patients have been correctly classified as having CAD (23/23) or no CAD (17/19). Over 97% (551/567) of segments were evaluable. Vessel-based analysis revealed sensitivity, specificity, positive and negative predictive value of 94.2% (CI 0.8% to 1.0%), 94.8% (CI 09% to 1.0%), 89.0% (CI 0.8% to 1.0%), 97.4% (CI 09% to 1.0%) and an accuracy of 94.6%.

CONCLUSIONS: Low dose CTCA allows evaluation of CAD with high accuracy, but delivers a significantly less effective radiation dose to patients compared to diagnostic invasive CA.

PMID: 19581273

Aug200916

1

Prognostic Value of a Comprehensive Cardiac Magnetic Resonance Assessment Soon After a First ST-Segment Elevation Myocardial Infarction

JACC Cardiovasc Imaging. 2009; 2(7):835-842

Bodi V, Sanchis J, Nunez J, Mainar L, Lopez-Lereu MP, Monmeneu JV, Rumiz E, Chaustre F, Trapero I, Husser O, Forteza MJ, Chorro FJ, Llacer A

OBJECTIVES: To evaluate the prognostic value of a comprehensive cardiac magnetic resonance (CMR) assessment soon after a first ST-segment elevation myocardial infarction (STEMI). Background: CMR allows for a simultaneous assessment of wall motion abnormalities (WMA), WMA with low-dose dobutamine (WMA-dobutamine), microvascular obstruction, and transmural necrosis. This approach has been proven to be useful to predict late systolic recovery soon after STEMI. Its prognostic value and the relative prognostic weight of these indexes are not well-defined.

METHODS: We studied 214 consecutive patients with a first STEMI treated with thrombolytic therapy or primary angioplasty discharged from hospital. In the first week (7 +/- 1 day after infarction), with CMR we determined the extent (number of segments) of WMA, WMA-dobutamine, microvascular obstruction, and transmural necrosis.

RESULTS: During a median follow-up of 553 days, 21 major adverse cardiac events (MACE) including 4 cardiac deaths, 6 nonfatal myocardial infarctions, and 11 readmissions for heart failure were documented. The MACE was associated with a larger extent of WMA (8 +/- 4 segments vs. 5 +/- 3 segments, p < 0.001), WMA-dobutamine (6 +/- 4 segments vs. 4 +/- 3 segments, p = 0.004), microvascular obstruction (3 +/- 3 segments vs. 1 +/- 2 segments p <0.001), and transmural necrosis (7 +/- 3 segments vs. 3 +/- 3 segments, p < 0.001). In a complete multivariate analysis that included baseline characteristics, electrocardiogram, biomarkers, angiography, ejection fraction, left ventricular volumes, and all CMR indexes, WMA/segment (hazard ratio: 1.29 [95% confidence interval: 1.11 to 1.49], p = 0.001) and the extent of transmural necrosis/segment (hazard ratio: 1.30 [95% confidence interval: 1.12 to 1.51], p < 0.001) were the only independent prognostic variables.

CONCLUSIONS: A comprehensive CMR assessment is useful for stratifying risk soon after STEMI, but only the extent of systolic dysfunction and of transmural necrosis provide independent prognostic information.

PMID: 19608133