Brief report

Investigation of aortocoronary artery bypass grafts by multislice spiral computed tomography with electrocardiographic-gated image reconstruction

Coronary artery atherosclerosis resulting in ischemic cardiac disease is the leading cause of mortality in the United States. In symptomatic patients, invasive diagnostic methods like catheter angiography, intravascular ultrasound, or vascular endoscopy may be used. However, for primary prevention of atherosclerotic coronary artery disease in asymptomatic patients, non-invasive methods are more commonly utilized like stress imaging, single-photon emission computed tomography (SPECT) and coronary artery calcification scoring. Coronary computed tomographic angiography (CCTA) is an excellent diagnostic tool for detection of coronary artery plaque and ability to identify resultant stenoses with an excellent negative predictive value which can potentially result in optimal exclusion of the presence of coronary artery disease. Long term follow up after a negative CCTA has repeatedly demonstrated very low incidence of future adverse coronary events, attesting its predictive value. CCTA based management is associated with improved CAD outcome in stable angina. Coronary CTA is valuable in acute chest pain evaluation in the emergency department helping in better triage. CT perfusion and CT-FFR are both very promising tools for assessment of hemodynamic significance of coronary artery stenosis.

L'athérosclérose des artères coronaires entraînant une cardiopathie ischémique est la principale cause de mortalité aux États-Unis. Chez les patients symptomatiques, des méthodes de diagnostic invasives comme l'angiographie par cathéter, l'échographie intravasculaire ou l'endoscopie vasculaire peuvent être utilisées. Cependant, pour la prévention primaire de la coronaropathie athérosclérotique chez les patients asymptomatiques, des méthodes non invasives sont plus couramment utilisées, comme l'imagerie d'effort, la tomographie par émission monophotonique (SPECT) et la notation de la calcification des artères coronaires. L'angiographie coronarienne par tomodensitométrie (CCTA) est un excellent outil de diagnostic pour la détection de la plaque coronarienne et la capacité d'identifier les sténoses résultantes avec une excellente valeur prédictive négative, ce qui peut permettre d'exclure de manière optimale la présence d'une maladie coronarienne. Le suivi à long terme après une CCTA négative a démontré à plusieurs reprises une très faible incidence d'événements coronariens indésirables futurs, ce qui atteste de sa valeur prédictive. La prise en charge basée sur la CCTA est associée à une amélioration de l'issue de la maladie coronarienne dans l'angine stable. L'angiographie coronarienne est précieuse dans l'évaluation des douleurs thoraciques aiguës aux urgences, car elle permet un meilleur triage. La TDM de perfusion et la TDM-FFR sont deux outils très prometteurs pour évaluer l'importance hémodynamique de la sténose des artères coronaires.

To assess the effect of DuraGraft (Somahlution Inc, Jupiter, Fla), an intraoperative graft treatment, on saphenous vein grafts in patients undergoing isolated coronary artery bypass grafting.

Within patients, 2 saphenous vein grafts were randomized to DuraGraft or heparinized saline. Multidetector computed tomography angiography at 1, 3, and 12 months assessed change in wall thickness (primary end point at 3 months), lumen diameter, and maximum narrowing for the whole graft and the proximal 5-cm segment. Safety end points included graft occlusion, death, myocardial infarction, and repeat revascularization.

At 3 months, no significant changes were observed between DuraGraft- and saline-treated grafts (125 each) for wall thickness, lumen diameter, and maximum narrowing. At 12 months, DuraGraft-treated grafts demonstrated smaller mean wall thickness, overall (0.12 ± 0.06 vs 0.20 ± 0.31 mm; P = .02) and in the proximal segment (0.11 ± 0.03 vs 0.21 ± 0.33 mm; P = .01). Changes in wall thickness were greater in the proximal segment of saline-treated grafts (0.09 ± 0.29 vs 0.00 ± 0.03 mm; P = .04). Increase in maximum graft narrowing was larger in the proximal segment in the saline-treated grafts (4.7% ± 12.7% vs 0.2% ± 3.8%; P = .01). Nine DuraGraft and 11 saline grafts had occluded or thrombosed. One myocardial infarction was associated with a saline graft occlusion. No deaths or revascularizations were observed.

DuraGraft demonstrated a favorable effect on wall thickness at 12 months, particularly in the proximal segment. Longer-term follow-up in larger studies is needed to evaluate the effect on clinical outcomes.

Coronary artery disease (CAD) continues to be a leading cause of morbidity and mortality worldwide. Although invasive coronary angiography has previously been the gold standard in establishing the diagnosis of CAD, there is a growing shift to more appropriately use the cardiac catheterization laboratory to perform interventional procedures once a diagnosis of CAD has been established by noninvasive imaging modalities rather than using it primarily as a diagnostic facility to confirm or refute CAD. With ongoing technological advancements, noninvasive imaging plays a pre-eminent role in not only diagnosing CAD but also informing the choice of appropriate therapies, establishing prognosis, all while containing costs and providing value-based care. Multiple imaging modalities are available to evaluate patients suspected of having coronary ischemia, such as stress electrocardiography, stress echocardiography, single-photon emission computed tomography myocardial perfusion imaging, positron emission tomography, coronary computed tomography (CT) angiography, and magnetic resonance imaging. These imaging modalities can variably provide functional and anatomical delineation of coronary stenoses and help guide appropriate therapy. This review will discuss their advantages and limitations and their usage in the diagnostic pathway for patients with CAD. We also discuss newer technologies such as CT fractional flow reserve, CT angiography with perfusion, whole-heart coronary magnetic resonance angiography with perfusion, which can provide both anatomical as well as functional information in the same test, thus obviating the need for multiple diagnostic tests to obtain a comprehensive assessment of both, plaque burden and downstream ischemia. Recognizing that clinicians have a multitude of tests to choose from, we provide an underpinning of the principles of ischemia detection by these various modalities, focusing on anatomy vs physiology, the database justifying their use, their prognostic capabilities and lastly, their appropriate and judicious use in this era of patient-centered, cost-effective imaging.

Depuis l’introduction de la génération de scanners 64-barettes, l’exactitude et la robustesse du diagnostic de la maladie coronaire ont progressé. L’intérêt majeur du scanner cardiaque est l’exclusion de la maladie coronaire par son excellente valeur prédictive négative. Actuellement, ses applications s’étendent grâce aux innovations aussi bien en terme d’évolution technologique des systèmes de scanner ou des stents implantés, que de l’évolution des procédures chirurgicales comme le TAVI.

Since the introduction of the 64-generation scanners, the accuracy and robustness of the diagnosis of coronary artery disease has progressed. The main advantage of cardiac CT is the exclusion of coronary artery disease by its excellent negative predictive value. Currently, cardiac CT applications extend thanks to innovations both in terms of technological development systems scanner or stents implanted, that the evolution of surgical procedures such as TAVI.

To assess the accuracy of coronary CTA in detection of coronary artery bypass graft patency, occlusion and stenosis.

Twenty-four patients with past history of coronary bypass surgery were included in this study and underwent MDCT coronary angiography. Invasive coronary angiography was done within 2 weeks of MDCT coronary angiography. All grafts considered patent were then evaluated for the presence of significant stenosis. Significant stenosis was defined as reduction in diameter of more than 50%.

All the MDCT scans were interpretable and a total number of 78 CABG conduits were analyzed. At MDCT angiography 4 (5.2%) grafts were classified as occluded and 74 (94.8%) grafts were patent. Significant stenosis was detected in 7 (9.4%) out of the 74 patent grafts. At invasive coronary angiography; when occlusion and significant stenosis pooled together they were 9 grafts; 4 arterial and 5 venous. All these 9 grafts were detected at MSCT (sensitivity is 100%). In 67 out of 69 grafts occlusion or significant stenosis was correctly ruled out (specificity 97.1%). The diagnostic accuracy of MDCT angiography when compared with invasive angiography was 97.4%. The negative predictive value was 100% and positive predictive value was 81.8%.

MDCT coronary angiography is an accurate imaging technique for the evaluation of CABG patency and in detection of graft stenosis and confirms of previous studies using 64 MDCT.