Intra-operative quality assessment of coronary artery bypass grafts

Abstract

Early coronary artery bypass graft (CABG) failure is a troubling complication that may result in a wide range of problems, including refractory angina, myocardial infarction, low cardiac output, arrhythmia, and fatal heart failure. Early graft failures are related to poor quality and size of the distal native vascular bed, coagulation abnormalities, or technical problems involving the graft conduits and anastomoses. Unfortunately, graft failure is difficult to detect during surgery by visual assessment, palpation, or conventional monitoring. We evaluated the accuracy and utility of a transit-time, ultrasonic flow measurement system for measurement of CABGs. There were no differences between transit-time measurements and volumetric-time collected samples in an in vitro circuit over a range of flows from 10 to 100ml/min (Bland and Altman Plot, 1.96 SD). Two hundred and ninety-eight CABGs were examined in 125 patients. Graft flow rate was proportional to the target vessel diameter. Nine technical errors were detected and corrected. Flow waveform morphology provided valuable information related to the quality of the anastamosis, which led to the immediate correction of technical problems at the time of surgery.

Continuous flow phantom for the calibration of an ultrasonic transit-time flowmeter

“…No papers regarding a TTFM flow phantom designed with silicone tubes in the measurement regions were found. Water has been the most cited fluid (Bednarik and May, 1995;Drost, 1978;Gordon, 1995), except for cases in which salt solutions were employed in ex vivo veins and arteries (Amaral and Michelini, 1997;Beldi et al, 2000;Groom et al, 2001;Lundell et al, 1993). The use of hydrostatic pressure for pressurization was found in the Transonic System calibration manual (Transonic…, 2009).…”

“…Among the TTFM calibration phantoms found in the literature, some use hydrostatic pressurization (Gordon, 1995;Transonic…, 2009) while others employ peristaltic pumps (Beldi et al, 2000;Groom et al, 2001). The materials employed in the measurement region ranged from synthetic materials, such as latex (Drost, 1978;Transonic…, 2009) and dialysis tubing (Bednarik and May, 1995;Gordon, 1995), to biological materials, such as saphenous human vein grafts (Beldi et al, 2000;Groom et al, 2001), carotid arteries of rats (Amaral and Michelini, 1997), sheep (Lundell et al, 1993) and pigs (Beldi et al, 2000).…”

“…The materials employed in the measurement region ranged from synthetic materials, such as latex (Drost, 1978;Transonic…, 2009) and dialysis tubing (Bednarik and May, 1995;Gordon, 1995), to biological materials, such as saphenous human vein grafts (Beldi et al, 2000;Groom et al, 2001), carotid arteries of rats (Amaral and Michelini, 1997), sheep (Lundell et al, 1993) and pigs (Beldi et al, 2000). Water is the working fluid that is normally employed, but there are also reports of the use of saline solution in experiments with biological materials (Beldi et al, 2000;Groom et al, 2001). Furthermore, there is a case where red blood cells were dissolved in bypass fluid (Normosol -R) (Groom et al, 2001).…”

“…Water is the working fluid that is normally employed, but there are also reports of the use of saline solution in experiments with biological materials (Beldi et al, 2000;Groom et al, 2001). Furthermore, there is a case where red blood cells were dissolved in bypass fluid (Normosol -R) (Groom et al, 2001).…”

“…Known methods do not have a common experimental protocol and incur a high implementation cost (Amaral and Michelini, 1997;Bednarik and May, 1995;Beldi et al, 2000;Gordon, 1995;Groom et al, 2001;Lundell et al, 1993;Transonic…, 2009), which indicates the importance of establishing a well-defined method for TTFM calibration that is inexpensive and has an easy acquisition phantom.…”