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    A minimally invasive robotic surgery approach to perform totally endoscopic coronary artery bypass on beating hearts

    , Article Medical Hypotheses ; Volume 124 , 2019 , Pages 76-83 ; 03069877 (ISSN) Alamdar, A ; Hanife, S ; Farahmand, F ; Behzadipour, S ; Mirbagheri, A ; Sharif University of Technology
    Churchill Livingstone  2019
    The currently available robotic systems rely on rigid heart stabilizers to perform totally endoscopic coronary artery bypass (TECAB) surgery on beating hearts. Although such stabilizers facilitate the anastomosis procedure by immobilizing the heart and holding the surgery site steady, they can cause damage to the heart tissue and rupture of the capillary vessels, due to applying relatively large pressures on the epicardium. In this paper, we propose an advanced robotic approach to perform TECAB on a beating heart with minimal invasiveness. The idea comes from the fact that the main pulsations of the heart occur as excursions in normal direction, i.e., perpendicular to the heart surface. We... 

    Design and Fabrication of Engineered Biomaterials for Tissue Engineering Applications such as Cardiovascular System

    , M.Sc. Thesis Sharif University of Technology Khayat Norouzi, Sara (Author) ; Shamlou, Amir (Supervisor)
    Cardiovascular diseases are the leading cause of death all over the world, even more common than cancers. The first reason of mortality in Iran according to statistics is the occlusion of coronary arteries. Unfortunately almost one third of patients doesn’t have enough blood vessels to be used in the bypass surgery and need artificial vessels. These artificial blood vessels with small diameters (less than 6 mm) will fail quickly. As a result there is an increasing demand for tissue engineered blood vessels which are capable of enduring high blood pressures. An artificial blood vessel should mimic both structure and mechanical properties of the real one. Blood vessels have layered structures,... 

    Simulation of Competitive Flow in the Coronary Arteries Bypass

    , M.Sc. Thesis Sharif University of Technology Azimi Nejad, Milad (Author) ; Firoozabadi, Bahar (Supervisor)
    Atherosclerosis is one of the most important factors for mortality and morbidity in the world. Coronary artery bypass graft (CABG) is applied for treatment of this disease which in this surgery, the patient vessels, such as internal thoracic artery and saphenous vein, are harvested and grafted to the coronary arteries. The graft success and its performance in short and long-term are depended on the much factors e.g. the severity of stenosis in the coronary artery. It should be noted that the low level of stenosis in the coronary artery causes the creation of undesirable phenomenon of competitive flow in the grafts after the surgery which this phenomenon has been reported as a cause of graft... 

    Design an Analysis of a Heartbeat Motion Compensation Controller in a Robotic Coronary Artery Bypass Graft Surgery

    , M.Sc. Thesis Sharif University of Technology Rahmati, Zahra (Author) ; Behzadipour, Saeed (Supervisor)
    The Coronary artery bypass grafting surgery is one of the most complicated and invasive surgeries, in which the chest is cleaved up to 20 cm. Also, heart motion with 1-2Hz frequency bothers surgeons to perform on. This leads surgeons to get interested in minimally invasive robotic surgery methods. The idea is to synchronize the robot motion with heart, in order for surgeons to perceive it stationary. This needs 3 major stages: online taking of data, estimate the future heart motion, and control the robot. First studies employ visual seroving for control demand. Later studies, although differ in data collection methods, rely on classic error-based feedback controllers, such as PID. Fast... 

    Design, Analysis, and Experimental Study of a Slave Robot for Minimally Invasive Beating Heart Surgery

    , Ph.D. Dissertation Sharif University of Technology Alamdar, Alireza (Author) ; Farahmand, Farzam (Supervisor)
    In this study, a practical approach for robotic beating heart surgery was proposed. This approach eliminates lateral movements of the heart and compensates for normal heart movement by using 1 DOF heart stabilizer and 1 DOF heart compensator simultaneously. It is a compromise between complete fixation of the heart, which damages the heart tissue, on one hand and complex and impractical compensation of the free heart movement on the other. One of the core components of the proposed system is the slave robot, which includes a 1 DOF compensator and a 4 DOF tool holder robot. Based on the selected laparoscopic tool, a modified agile-eye mechanism for activating the wrist was introduced,... 

    Patient-specific fluid–structure interaction simulation of the LAD-ITA bypass graft for moderate and severe stenosis: A doubt on the fractional flow reserve-based decision

    , Article Biocybernetics and Biomedical Engineering ; Volume 42, Issue 1 , 2022 , Pages 143-157 ; 02085216 (ISSN) Tajeddini, F ; Firoozabadi, B ; Pakravan, H. A ; Ahmadi Tafti, S. H ; Sharif University of Technology
    Elsevier B.V  2022
    Fractional flow reserve (FFR)-based decision improves the outcomes of percutaneous coronary intervention (PCI) for some patients, while its effectiveness in improving the results of coronary artery bypass graft (CABG) is unclear, in particular for moderate stenosis. It may be due to the fact that FFR cannot take into account the impacts of competitive flow (CF), intimal hyperplasia (IH), as well as compliance mismatch (CMM). As a result, two questions arise 1) whether FFR is a sufficient factor to decide to perform the CABG for patients with moderate to severe stenosis or not and 2) whether post-operative FFR shows the effectiveness of a graft. To shed light on this matter, two...