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Pressure characteristics in arterial grafts for coronary bypass surgery
T Tedoriya1, M Kawasuji, N Sakakibara
1First Department of Surgery, Kanazawa University School of Medicine, Japan.
Insights
Internal thoracic and gastroepiploic artery grafts used in coronary artery bypass surgery show lower diastolic pressures than the ascending aorta. Anatomical factors likely explain the reduced blood flow capacity in these arterial grafts.
Area of Science:
- Cardiovascular Surgery
- Biomedical Engineering
- Vascular Physiology
Background:
- Coronary artery bypass grafting (CABG) frequently utilizes arterial grafts.
- Understanding the hemodynamic properties of these grafts is crucial for optimizing surgical outcomes.
- Internal thoracic artery (ITA) and gastroepiploic artery (GEA) are common arterial conduits in CABG.
Purpose of the Study:
- To compare the hemodynamic properties, specifically pressure waveforms, of ITA and GEA grafts against the ascending aorta.
- To investigate the factors influencing blood flow capacity in arterial grafts used for CABG.
Main Methods:
- Simultaneous recording of pressure waveforms from the ascending aorta and arterial grafts (ITA and GEA) in 28 CABG patients before cardiopulmonary bypass.
- Measurement of systolic, diastolic, and mean pressures.
- Calculation of mean systolic and diastolic pressures based on waveform areas and time.
Main Results:
- No significant difference in systolic pressure was observed between the ascending aorta and the arterial grafts.
- Diastolic pressures were significantly lower in ITA (55±7 mmHg) and GEA (51±6 mmHg) grafts compared to the ascending aorta (64±9 mmHg).
- Mean pressures were also lower in ITA (65±9 mmHg) and GEA (59±7 mmHg) grafts compared to the ascending aorta (75±9 mmHg).
- ITA grafts exhibited higher diastolic and mean pressures than GEA grafts.
- Arterial graft pressure waveforms showed narrower contours and a distinct notch compared to the ascending aorta.
Conclusions:
- Reduced diastolic pressure in arterial grafts, particularly GEA, may contribute to their inferior flow capacity.
- The anatomical characteristics of the arterial grafts are likely responsible for the observed hemodynamic differences.
- Further research into graft selection and modification may improve long-term patency and function.
Abstract:
The haemodynamic properties of arterial grafts were studied by measuring the pressure waveform at the tip of the grafts in 28 patients who underwent coronary artery bypass surgery (CABG). The internal thoracic and gastroepiploic arteries were harvested as pedicles for CABG. Pressure wave of the ascending aorta and arterial grafts were simultaneously recorded with an electrocardiogram under stable haemodynamic conditions before cardiopulmonary bypass. Systolic, diastolic and mean pressures were measured, and mean systolic and diastolic pressures calculated for systolic and diastolic areas divided by time. The ascending aorta showed high sustained diastolic pressure that decreased gradually. Pressures in the internal thoracic and gastroepiploic artery grafts had narrow contours and decreased rapidly. Pressure waveforms in the internal thoracic and gastroepiploic artery grafts had a notch between the systolic and diastolic contours. There was no difference in systolic pressure between the ascending aorta and internal thoracic and gastroepiploic artery grafts. Diastolic pressures were 64(9), 55(7), and 51(6) mmHg in the ascending aorta and internal thoracic and gastroepiploic artery, respectively. Mean(s.d.) pressures were 75(9), 65(9) and 59(7) mmHg in the ascending aorta and internal thoracic and gastroepiploic artery grafts, respectively. Diastolic and mean pressures in the internal thoracic artery grafts were significantly lower than in the ascending aorta but significantly higher than in the gastroepiploic artery grafts. The mean(s.d.) calculated diastolic pressure in the internal thoracic artery grafts was significantly lower than in the ascending aorta but significantly higher than in the gastroepiploic artery grafts. The inferior capacity of flow through the arterial grafts may be mainly attributable to reduced diastolic pressure, which is caused by anatomical characteristics.(ABSTRACT TRUNCATED AT 250 WORDS)