Thermal coronary angiography: A method for assessing graft patency and coronary anatomy in coronary bypass surgery (original) (raw)
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European Journal of Cardio-Thoracic Surgery, 2003
Objective: Intraoperative coronary angiography has always been favoured by cardiac surgeons. Thermal coronary angiography (TCA) is a useful method for intraoperative control of graft patency. It detects heat differences between tissues, provides easy-to-interpret angiographic images and even measures the flow of the grafts quantitatively. Methods: Between January 2000 and January 2002, TCA has been used in scheduled coronary bypass operations. Upon completion of each distal anastomosis, the perfusion of the distal arterial tree from the graft was evaluated with a thermal camera. Results: TCA was applied to 1401 patients, mean age 60.97^9.61 years, who underwent simple coronary artery bypass grafting (CABG) procedures. A total of 4105 thermal images were obtained including 2161 venous, 1355 single internal thoracic artery (ITA), 56 bilateral ITA and 477 radial artery grafts. Image quality was not sufficient in 34 grafts (1.57%) due to either deep intramyocardial vessels or excessive epicardial fat tissue. Technical failures in three ITA anastomoses were detected and revised before the cross-clamp was removed. Flow-restricting lesions distal to the anastomosis on the left anterior descending artery (LAD) in nine patients were managed with a secondary distal bypass graft (five patients) or plaque splitting and anastomotic revision (four patients). Endarterectomy was combined in seven patients since the graft flow and the distal visualization was not satisfactory, although the anastomoses were performed on a good lumen. Angiographically undetected diagonal arteries were revascularized in 11 patients with totally occluded LAD vessels. Conclusion: Thermal imaging provides decisive coronary angiographies, and detects the perfusion area and flow of the implanted graft. It allows real-time detection of technical failures, reveals unexpected occluding plaques or any kind of flow-restricting lesions, and gives the chance of refinement of the anastomosis during the arrest period. We believe that the thermal imaging technique is a safe, noninvasive and feasible method to document the quality of the myocardial revascularization intraoperatively.
Medicina (Kaunas, Lithuania), 2009
Thermography is a relatively new contact-free method used in experimental and clinical studies and in cardiovascular surgery to investigate the myocardium and coronary artery function. Objects of complex study included mongrel dogs and patients with coronary artery disease who underwent cardiac surgery. For active dynamic thermography, we used a thermovision camera "A20V" (FLIR Systems, USA). Our data indicate that both experimental and clinical study performed on beating hearts could be an important approach to interoperation inspection of autovenous graft function. An infrared camera also can be successfully used to determine the extent of ischemic damage to the myocardium, heart, and blood vessels during surgery as a significant prognostic tool for evaluating outcome after cardiac operation.
The Journal of Thoracic and Cardiovascular Surgery, 2006
Objectives: Intraoperative application of thermal coronary angiography based on dynamic infrared imaging leads to useful qualitative information concerning coronary artery bypass graft flow and anatomy. Additional quantitative flow estimation is desirable to detect graft failures. The aim of this study was to develop a heat-transfer model for quantitative flow estimation in an experimental setup. The first clinical results in coronary artery bypass grafting are reported.
Technology and Health Care, 2018
BACKGROUND: In this paper a method is proposed to evaluate the heart's coronary vessels' status based on the elimination of large coronary branches from IR-thermal image. This method makes it possible to determine nutrient cardiac blood circulation by calculation of the rate of heat spreading in small coronary vessels in the myocardium at hypothermia and hyperthermia under the conditions of artificial blood circulation. OBJECTIVE: The objective of the paper includes a theoretical substantiation of the proposed method for evaluation of the heart's coronary vessels' status and an experimental investigation of the efficiency of the method. METHODS: In the experiment, the dynamics of temperature distribution in the myocardium were registered by using thermal imaging cameras Flir i7 and Thermo Cam E300. RESULTS: Processing of the myocardium's thermographic images and the results of heat spreading modeling make it possible to single out the temperature profiles of the visible myocardium zones and to establish the presence of coronary arteries in them. CONCLUSIONS: The method makes it possible to monitor the heart temperature at hypothermia and hyperthermia; additionally, it makes it possible to evaluate the efficiency of the coronary artery bypass graft surgery performed during open heart operation.
Intravascular thermography: Immediate functional and morphological vascular findings
European Heart Journal, 2004
Aim To investigate safety, feasibility, and injurious effect on endothelial cells of a thermography catheter as well as effect of flow on measured temperature in nonobstructive arteries. Methods and results Safety and feasibility were tested in both rabbit aortas and pig coronary arteries. Evaluation of endothelial damage by the catheter (acute, 7 and 14 days) was performed in pig coronaries using Evans Blue, scanning electron microscopy (SEM) and Factor-VIII antibody and compared with normal arteries and arteries that underwent intravascular ultrasound (IVUS). The effect of flow on temperature heterogeneity was analysed both in vitro and in vivo conditions. All procedures were successful without any adverse events; intra-and inter-operator variability was low. Intracoronary use of the catheter was associated with acute but reversible deendothelialization, paralleling the findings associated with IVUS use. Changes in flow velocities under physiologic flow conditions did not significantly influence the temperature differences measured both in vitro and in vivo; temperature heterogeneity was more pronounced in absence of flow. Conclusion Intracoronary thermography using a dedicated catheter is safe and feasible with a similar degree of de-endothelialization as IVUS. Temperature heterogeneity remained unchanged under normal physiologic flow conditions allowing clinical use of thermography.
Post-mortem thermal angiography: a pilot study on swine coronary circulation
International Journal of Legal Medicine
Thermal imaging (TI) allows the detection of thermal patterns emitted from objects as a function of their temperature in the longinfrared spectrum and produces visible images displaying temperature differences. The aim of this pilot study was to test TI to visualize the coronary circulation of swine hearts. Thirty swine hearts were prepared for ex situ coronarography, and thermal images were acquired through a FlirOne thermal camera (FLIR Systems®) paired with a Google Android Smartphone. Coronary arteries were cannulated, namely the anterior interventricular artery, the circumflex branch of the left coronary artery, and the right coronary artery. The heart was cooled, and contrast medium (CM) consisting of distilled water heated to 40°C was injected in a coronary vessel, while thermal images were captured. These steps were repeated for each coronary vessel and under experimentally simulated coronary heart disease. Thermal imaging coronarography (TIC) allowed a clear representation of the morphology and course of the coronary vessels and of experimentally simulated coronary heart disease, moreover, demonstrated to be easy to perform during or after autopsies on ex situ hearts, non-destructive, reproducible, and cheap. On the basis of these preliminary results, TIC might allow a subsequent more focused and comprehensive cardiopathological examination of the heart, which remains mandatory for the definitive diagnosis of coronary heart disease. Although these preliminary results seem encouraging, further systematic studies on human hearts, both normal and pathological, are necessary for estimating the sensitivity and specificity of the proposed method and to draw any definitive conclusion. Keywords Thermal imaging. Post-mortem coronarography. Cardiopathology. Post-mortem imaging. Ex situ coronarography Highlights • Thermal imaging allows the clear imaging of swine coronary vessels. • Thermal imaging recognizes simulated occlusion/sub-occlusion of coronary arteries. • Thermal imaging coronarography (TIC) is cheap and easy to perform. • TIC might be performed during the autopsy or even later and in a different setting. • TIC is reproducible and non-destructive.