Standardized evaluation framework for evaluating coronary artery stenosis detection, stenosis quantification and lumen segmentation algorithms in computed tomography angiography.

Though conventional coronary angiography (CCA) has been the standard of reference for diagnosing coronary artery disease in the past decades, computed tomography angiography (CTA) has rapidly emerged, and is nowadays widely used in clinical practice. Here, we introduce a standardized evaluation framework to reliably evaluate and compare the performance of the algorithms devised to detect and quantify the coronary artery stenoses, and to segment the coronary artery lumen in CTA data. The objective of this evaluation framework is to demonstrate the feasibility of dedicated algorithms to: (1) (semi-)automatically detect and quantify stenosis on CTA, in comparison with quantitative coronary angiography (QCA) and CTA consensus reading, and (2) (semi-)automatically segment the coronary lumen on CTA, in comparison with expert's manual annotation. A database consisting of 48 multicenter multivendor cardiac CTA datasets with corresponding reference standards are described and made available. The algorithms from 11 research groups were quantitatively evaluated and compared. The results show that (1) some of the current stenosis detection/quantification algorithms may be used for triage or as a second-reader in clinical practice, and that (2) automatic lumen segmentation is possible with a precision similar to that obtained by experts. The framework is open for new submissions through the website, at http://coronary.bigr.nl/stenoses/.

Technical aspects of total revascularization in off-pump coronary bypass via sternotomy approach.

BACKGROUND: Cardiopulmonary bypass and cardioplegic arrest result in known physiologic inflammatory, coagulopathic, and embolic states that may result in end-organ damage. Interest in off-pump complete coronary revascularization using sternotomy exposure is therefore increasing. METHODS: Using specific surgical and anesthetic techniques, we have been able to achieve total revascularization using off-pump coronary artery bypass grafting procedures (OP-CAB) through a sternotomy approach. Exposure techniques and local stabilization are tailored to individual vessels and cardiac regions. Vascular control is achieved with silicone-elastomer loops, occluders, and shunts. Poor ventricular function, advanced age, and other comorbid conditions, in and of themselves, were not considered contraindications to OP-CAB. Cardiomegaly or situations of small, intramyocardial, or heavily calcified vessels were relative contraindications to OP-CAB. RESULTS: Of 141 sternotomy OP-CAB cases, 132 (93.6%) were completely off-pump. The mean number of OP-CAB grafts per patient in the cases that were completely off-pump was 3.3 (range, 1 to 6). The 30-day operative mortality was 0%. There were four instances of intraoperative cardiac arrest, precipitated by vascular occlusion of the right coronary artery or manipulating a cardiomegalic heart. Advanced age (> or = 80 years) or profound ventricular dysfunction (ejection fraction < or = 0.25) was present in a considerable percentage of patients (10.6% and 9.9%, respectively). CONCLUSIONS: Off-pump coronary artery bypass grafting is successful for total revascularization in large numbers of patients. Anatomic factors, including cardiomegaly and small, intramyocardial, or heavily calcified vessels are possible contraindications to OP-CAB. Patients at highest risk for undergoing cardiopulmonary bypass, including those of advanced age and having ventricular dysfunction, are precisely the ones in whom OP-CAB may be the most useful.