Alberto Formenti

Diagnostic accuracy of coronary computed tomography angiography: a comparison between prospective and retrospective electrocardiogram triggering.

OBJECTIVES The aim of this study was to compare the diagnostic performance of multidetector computed tomography (MDCT) with prospective electrocardiogram (ECG) triggering versus retrospective ECG triggering. BACKGROUND MDCT allows the noninvasive visualization of the coronary arteries. However, radiation exposure is a reason for concern. METHODS One hundred eighty consecutive patients scheduled for invasive coronary angiography were enrolled in this study. Twenty patients were excluded due to contraindications to sustain MDCT. Of the 160 remaining patients, 80 were studied with MDCT with prospective ECG triggering (Group 1) and 80 with a retrospective ECG triggering (Group 2). The individual radiation dose exposure was estimated. RESULTS In nonstented segments, the evaluability of Groups 1 and 2 was 96% versus 97%, respectively (p = 0.05), the accuracy in segment-based model was 93% versus 96%, respectively (p < 0.05) including diagnostic segments and 91% versus 94%, respectively (p < 0.01) including all segments, whereas the accuracy in a patient-based model was 98% in both groups. In stented segments the evaluability in Groups 1 and 2 was 92% versus 94%, respectively, and the accuracy was 93% versus 92%, respectively, including diagnostic stented segments and 90% versus 89%, respectively, including all stented segments. Group 1 presented lower radiation dose compared with Group 2 (5.7 +/- 1.5 mSv vs. 20.5 +/- 4.3 mSv, p < 0.01). CONCLUSIONS Prospective ECG-triggering computed tomography allows an accurate detection of coronary stenosis, despite a slight reduction of diagnostic performance, with a low radiation dose.

A Long-Term Prognostic Value of Coronary CT Angiography in Suspected Coronary Artery Disease

OBJECTIVES The aim of this study was to assess the long-term prognostic role of multidetector computed tomography coronary angiography (CTA) in patients with suspected coronary artery disease (CAD). BACKGROUND Use of CTA is increasing in patients with suspected CAD. Although there is a large body of data supporting the prognostic role of CTA for major adverse cardiac events in the intermediate term, its long-term prognostic role in patients with suspected CAD is not well studied. METHODS Between February 2005 and March 2008, 1,304 consecutive patients were prospectively studied with CTA for detecting the presence and assessing extent of CAD (disease extension and coronary plaque scores). Patients were classified according to the presence of normal coronaries and nonobstructive (<50%) and obstructive (>50%) coronary lesions. The composite rates of hard cardiac events (cardiac deaths and nonfatal myocardial infarctions) and all cardiac events (including late revascularization) were the endpoints of the study. RESULTS Seventy patients were excluded because their CTA data were uninterpretable. Of the remaining 1,234 patients, clinical follow-up (mean 52 ± 22 months) was obtained for 1,196 (97%). A total of 475 events were recorded, with 136 hard events (18 cardiac deaths and 118 nonfatal myocardial infarctions) and 123 late revascularizations. A total of 216 patients with early elective revascularizations were excluded from the survival analysis. Significant independent predictors of events in multivariate analysis were multivessel disease and left main CAD. Cumulative event-free survival was 100% for hard and all events in patients with normal coronary arteries, 88% for hard events and 72% for all events in patients with nonobstructive CAD, and 54% for hard events and 31% for all events in patients with obstructive CAD. Multivessel CAD was associated with a higher rate of hard cardiac events. CONCLUSIONS CTA provides prognostic information in patients with suspected CAD and unknown cardiac disease, showing excellent long-term prognosis when there is no evidence of atherosclerosis and allowing risk stratification when CAD is present.

Feasibility and accuracy of a comprehensive multidetector computed tomography acquisition for patients referred for balloon-expandable transcatheter aortic valve implantation

BACKGROUND The aim of this study was to assess the accuracy of a comprehensive multidetector computed tomography (MDCT) evaluation of the aortic annulus (AoA), coronary artery disease (CAD), and peripheral vessels in patients referred for transcatheter aortic valve implantation (TAVI). METHODS In 60 patients referred for TAVI, the following parameters were assessed with 64-slices MDCT and compared with transesophageal echocardiography (TEE), invasive coronary angiography (ICA), and peripheral angiography: AoA maximum diameter (Max-AoA-D(MDCT)), minimum diameter (Min-AoA-D(MDCT)), and area; lumen morphology index ([Max-AoA-D(MDCT)/Min-AoA-D(MDCT)]); length of the left, right, and non-coronary aortic leaflets; degree (grades 1-4) of aortic leaflet calcifications; distance between AoA and left main coronary ostium and between AoA and right coronary ostium CAD and peripheral vessel disease. RESULTS The Max-AoA-D(MDCT) and Min-AoA-D(MDCT) were 25.1 ± 2.8 and 21.2 ± 2.2 mm, respectively, with high correlation versus AoA diameter measured with TEE (r = 0.82 and 0.86, respectively). The area of AoA, systolic and diastolic lumen morphology index were 410 ± 81.5 mm(2), 1.19 ± 0.1 and 1.22 ± 0.11, respectively. Aortic leaflet calcification score was 3.3 ± 0.5. The lengths of left, right, and non-coronary aortic leaflets were 14.2 ± 2.4, 13.7.1 ± 2.1, and 14.5 ± 2.6 mm, whereas distances between AoA and the left main coronary ostium and between AoA, and the right coronary ostium were 13.7 ± 2.9 and 15.8 ± 3.5 mm, respectively. Feasibility, negative predictive value, and accuracy for CAD detection versus ICA were 87%, 100% (CI 100-100), and 96% (95% CI 94-100), respectively. All patients (N = 17) who were ineligible for TAVI were correctly detected by MDCT. CONCLUSIONS A comprehensive MDCT evaluation of patients referred for TAVI is feasible, provides more accurate assessment than TEE of AoA morphology, and may replace peripheral angiography in all patients and ICA in patients without significant CAD.

Coronary Artery Disease: Diagnostic Accuracy of CT Coronary Angiography—A Comparison of High and Standard Spatial Resolution Scanning

PURPOSE To compare the image quality, evaluability, diagnostic accuracy, and radiation exposure of high-spatial-resolution (HR, 0.23-mm) computed tomographic (CT) coronary angiography with standard spatial resolution (SR, 0.625-mm) 64-section imaging in patients at high risk for coronary artery disease (CAD) by using invasive coronary angiography (ICA) as the reference method. MATERIALS AND METHODS Written informed consent was obtained from all patients, and the study protocol was approved by the institutional ethical committee. Patients at high risk for CAD (n = 184) who were scheduled for ICA were randomly assigned for study with SR (n = 91) or HR (n = 93) coronary CT angiography before they underwent ICA. To compare the two groups, the Student t test or Wilcoxon test were used to evaluate differences in continuous variables. The χ(2) test or Fisher exact test were used, as appropriate, for categorical data. The McNemar test was used to compare the diagnostic performance of coronary CT angiography versus that of ICA in each group. RESULTS HR coronary CT angiography showed a higher image quality score (3.7 vs 3.4, P < .001) and evaluability (97% vs 92%, P < .002). In a segment-based analysis, HR coronary CT angiography showed a higher specificity, positive predictive value, and accuracy in comparison with SR coronary CT angiography (98%, 91%, and 99% vs 95%, 80%, and 95%, respectively; P < .001). Moreover, HR coronary CT angiography showed a better agreement with ICA for calcified plaques compared with SR coronary CT angiography and ICA (83% vs 53%, P < .001). In a patient-based analysis, HR coronary CT angiography showed higher specificity and accuracy compared with SR coronary CT angiography (91% and 98% vs 46% and 92%, respectively; P < .01). No differences in radiation exposure were found between the two groups. CONCLUSION Improved evaluability and accuracy were seen with HR compared with SR coronary CT angiography of calcified coronary artery lesions, suggesting a potential use for this technology in patients at high risk for CAD.

PROGNOSTIC VALUE OF MULTIDETECTOR COMPUTED TOMOGRAPHY CORONARY ANGIOGRAPHY IN DIABETES: EXCELLENT LONG-TERM PROGNOSIS IN PATIENTS WITH NORMAL CORONARY ARTERIES

OBJECTIVE To assess the prognostic role of multidetector computed tomography coronary angiography (MDCT-CA) in patients with diabetes with suspected coronary artery disease (CAD). Use of MDCT-CA is increasing in patients with suspected CAD. However, data supporting its prognostic value in patients with diabetes are limited. RESEARCH DESIGN AND METHODS Between January 2006 and September 2007, 429 consecutive diabetic patients were prospectively studied with MDCT-CA for detecting the presence and assessing the extent of CAD (disease extension and coronary plaque scores). Patients were classified according to the presence of normal coronary arteries and nonobstructive (<50%) and obstructive (≥50%) coronary lesions. The composite rates of hard cardiac events (cardiac death, nonfatal myocardial infarction, unstable angina) and all cardiac events (including revascularization) were the end points of the study. RESULTS Twenty-four patients were excluded because MDCT-CA data were not able to be interpreted. Of the remaining 405 patients, clinical follow-up (mean 62 ± 9 months) was obtained in 390 (98%). Multivariate analysis showed that predictors of hard and all events were obstructive CAD, three-vessel CAD, and left main coronary artery (LMCA) disease. Cumulative event-free survival was 100% for hard and all events in patients with normal coronary arteries, 78% for hard events and 56% for all events in patients with nonobstructive CAD, and 60% for hard events and 16% for all events in patients with obstructive CAD. Three-vessel CAD and LMCA disease were associated with a higher rate of hard cardiac events. CONCLUSIONS MDCT-CA provides long-term prognostic information for patients with diabetes with suspected CAD, showing excellent prognosis when there is no evidence of atherosclerosis and allowing risk stratification when CAD is present.

Diagnostic performance of two types of low radiation exposure protocol for prospective ECG-triggering multidetector computed tomography angiography in assessment of coronary artery bypass graft

BACKGROUND Multidetector computed tomography (MDCT) is useful in evaluation of coronary artery bypass graft (CABG). However, radiation exposure is a reason for concern. We compared diagnostic performance and effective dose of a new dedicated post-processing reconstruction algorithm with BMI-adapted scanning protocol (MDCT-XTe) vs. standard prospective ECG-triggering protocol (MDCT-XT) and retrospective ECG-triggering (MDCT-Helical), compared to invasive coronary angiography (ICA), in the assessment of grafts and nongrafted or distal runoff coronary arteries. METHODS One hundred and nineteen patients with 277 grafts were randomized to Group 1 based on BMI-adapted scanning protocol with prospective ECG-triggering (40 patients), Group 2 with prospective ECG-triggering (39 patients) and Group 3 (40 patients) with retrospective ECG-triggering. Data were acquired using 64-slice MDCT. RESULTS MDCT correctly assessed the patency of all CABG in 3 groups. After comparison with ICA, MDCT was able to correctly detect the occlusion or stenosis of CABG in all groups, with the exception of one case of Group 3. In Group 3 sensitivity, specificity, positive predictive value, negative predictive value and accuracy of CABG evaluation were 100%, 98.4%, 96.7%, 100% and 98.9%, respectively. In Groups 1 and 2 the diagnostic accuracy of CABG evaluation was 100%. Effective radiation dose was 3.5±1.4mSv in Group 1 vs. 7.4±2.6mSv in Group 2 vs. 27.8±9.4mSv in Group 3. CONCLUSIONS Our results indicated that MDCT-XTe and MDCT-XT have a diagnostic performance in the evaluation of CABG similar to MDCT-Helical, with a significant reduction of radiation exposure, specially for MDCT-XTe.

Low-dose CT coronary angiography with a novel IntraCycle motion-correction algorithm in patients with high heart rate or heart rate variability.

AIMS Motion artefacts due to high or irregular heart rate (HR) are common limitations of coronary computed tomography (CT) angiography (CCTA). The aim of the study was to evaluate the impact of a new motion-correction (MC) algorithm used in conjunction with low-dose prospective ECG-triggering CCTA on motion artefacts, image quality, and coronary assessability. METHODS AND RESULTS Among 380 patients undergoing CCTA for suspected CAD, we selected 120 patients with pre-scanning HR >70 bpm or HR variability (HRv) >10 bpm during scanning irrespective of pre-scanning HR or both conditions. In patients with pre-scanning HR <65 or ≥65 bpm, prospective ECG triggering with padding of 80 ms (58 cases) or padding of 200 ms (62 cases) was used, respectively. Mean pre-scanning HR and HRv were 70 ± 7 and 10.9 ± 4 bpm, respectively. Overall, the mean effective dose was 3.4 ± 1.3 mSv, while a lower dose (2.4 ± 0.9 mSv) was measured for padding of 80 ms. In a segment-based analysis, coronary assessability was significantly higher (P < 0.0001) with MC (97%) when compared with standard (STD) reconstruction (81%) due to a significant reduction (P < 0.0001) in severe artefacts (54 vs. 356 cases, respectively). An artefact sub-analysis showed significantly lower number of motion artefacts and artefacts related to chest movement with MC (16 and 4 cases) than with STD reconstruction (286 and 24 cases, P < 0.0001 and P < 0.05, respectively). The number of coronary segments ranked among those of excellent image quality was significantly higher with MC (P < 0.001). CONCLUSIONS The MC algorithm improves CCTA image quality and coronary assessability in patients with high HR and HRv, despite low radiation dose.

Diagnostic accuracy of multidetector computed tomography coronary angiography in 325 consecutive patients referred for transcatheter aortic valve replacement

BACKGROUND Multidetector computed tomography (MDCT) provides detailed assessment of valve annulus and iliofemoral vessels in transcatheter aortic valve replacement (TAVR) patients. However, data on diagnostic performance of MDCT coronary angiography (MDCT-CA) are scarce. The aim of the study is to assess diagnostic performance of MDCT for coronary artery evaluation before TAVR. METHODS A total of 325 consecutive patients (234 without previous myocardial revascularization, 49 with previous coronary stenting, and 42 with previous coronary artery bypass graft [CABG]) underwent invasive coronary angiography and MDCT before TAVR. MDCT-CA was performed using the same data set dedicated to standard MDCT aortic annulus evaluation. Multidetector computed tomography-CA evaluability and diagnostic accuracy in comparison with invasive coronary angiography as criterion standard were assessed. RESULTS The MDCT-CA evaluability of native coronaries was 95.6%. The leading cause of unevaluability was beam-hardening artifact due to coronary calcifications. In a segment-based analysis, MDCT-CA showed sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for detecting ≥50% stenosis of 91%, 99.2%, 83.4%, 99.6% and 98.8%, respectively. The MDCT-CA evaluability of coronary stents was 82.1%. In a segment-based analysis, MDCT-CA showed sensitivity, specificity, PPV, NPV, and accuracy for detecting ≥50% in-stent restenosis of 94.1%, 86.7%, 66.7%, 98.1%, and 88.3%, respectively. All CABGs were correctly assessed by MDCT-CA. In a patient-based analysis, MDCT-CA showed sensitivity, specificity, PPV, NPV, and accuracy of 89.7%, 90.8%, 80.6%, 95.4%, and 90.5%, respectively. CONCLUSIONS Multidetector computed tomography-CA allows to correctly rule out the presence of significant native coronary artery stenosis, significant in-stent restenosis, and CABG disease in patients referred for TAVR.

Additional clinical role of 64-slice multidetector computed tomography in the evaluation of coronary artery variants and anomalies

It is unknown whether multidetector computed tomography (MDCT) has an additional clinical value compared to invasive coronary angiography (ICA) in the characterization of congenital coronary artery anomalies (CAA). We studied 2757 consecutive patients with 64-slice MDCT and classified CAA according to anatomical criteria and pathophysiology-clinical relevance. The prevalence of anatomical variants was: left dominance circulation (8%), absence of left main artery (1.3%), presence of intermediate ramus (22.6%), origin of conus branch from aorta (10.6%) and of the sinus node branch from the left circumflex coronary artery (15.3%). Among 380 CAA (13.8 %) detected with MDCT, 322 (85%) were an occasional finding. In the remaining 58 patients, MDCT performed after ICA confirmed CAA in 40 (69%) cases and detected or provided additional and more detailed informations in 18 (31%). Of these 18 patients, 14 showed malignant CAA. MDCT is the ideal method for the evaluation of CAA, not only allowing a precise anatomic visualization of coronary tree, but also adding important details in malignant congenital anomalies.

Coronary stent evaluation with coronary computed tomographic angiography: comparison between low-osmolar, high-iodine concentration iomeprol-400 and iso-osmolar, lower-iodine concentration iodixanol-320.

BACKGROUND Reliability of coronary angiography by multidetector row CT (MDCT-CA) for stent evaluation is still a matter for debate, and it is unknown whether contrast medium characteristics may affect diagnostic performance of MDCT-CA. OBJECTIVE We compared iomeprol-400 with iodixanol-320 to evaluate coronary stents with MDCT-CA. METHODS We randomly assigned 254 patients undergoing coronary stent follow-up with the use of MDCT-CA to iomeprol-400 at 5.0 mL/sec flow rate (group 1; n = 83), iodixanol-320 at 6.2 mL/sec flow rate (group 2; n = 87), and iodixanol-320 at 5.0 mL/sec flow rate (group 3; n = 84). Heart rate (HR) immediately before and at the end of scanning, HR variation, premature heart beats, and heat sensation by visual analog scale during scanning were recorded. Mean attenuation was measured in the aortic root and coronary arteries. Image quality score and type of artifacts were assessed. RESULTS Mean attenuation was significantly lower in group 3 than in the other groups. In group 3, stent evaluability was significantly higher and artifact rate was significantly lower than in group 2 (99% vs. 91% and 4% vs. 15%) and group 1 (99% vs. 92% and 4% vs. 17%), respectively, mainly because of a significant lower rate of beam-hardening artifacts (3 cases in group 3 vs. 22 and 27 in groups 2 and 3, respectively). In group 3, visual analog scale, HR at the end of imaging, and number of patients with premature heart beats during the scan were significantly lower than in the other groups. CONCLUSIONS Iodixanol-320 provides better image quality of coronary stents, allowing higher MDCT-CA evaluability, than iomeprol-400.