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Right heart bypass for left circumflex coronary artery bypass grafting
Y Suematsu1, T Ohtsuka, K Miyaji
1Department of Cardiothoracic Surgery, University of Tokyo, Japan.
Insights
Right heart bypass (RHB) effectively stabilizes hemodynamics during off-pump coronary artery bypass grafting (CABG) by mitigating heart displacement effects. This technique offers a promising solution for managing hemodynamic disturbances in complex LCX surgeries.
Area of Science:
- Cardiovascular Surgery
- Medical Devices
- Hemodynamics
Background:
- Heart displacement during off-pump coronary artery bypass grafting (CABG) for left circumflex artery (LCX) exposure causes significant hemodynamic instability.
- Maintaining stable hemodynamics is crucial for patient safety during complex cardiac procedures.
Purpose of the Study:
- To evaluate the efficacy of right heart bypass (RHB) in stabilizing hemodynamics during LCX exposure in off-pump CABG.
- To compare the effects of RHB with Trendelenburg positioning on hemodynamic parameters.
Main Methods:
- Utilized a heparin-coated centrifugal pump for RHB without an oxygenator in a canine model.
- Continuously monitored hemodynamic parameters including aortic flow and mean arterial pressure.
- Assessed the impact of LCX exposure, Trendelenburg positioning, and varying RHB flows on hemodynamic stability.
Main Results:
- LCX exposure significantly decreased aortic flow and mean arterial pressure.
- Trendelenburg positioning partially recovered these hemodynamic values.
- RHB at 50% flow significantly improved hemodynamics, while 100% flow increased left atrial pressure.
Conclusions:
- RHB is highly effective in improving hemodynamics during LCX exposure in off-pump CABG.
- Appropriate RHB flow can provide safe hemodynamic assistance, though careful titration is necessary.
- RHB presents a viable strategy to manage hemodynamic disturbances in challenging LCX revascularization procedures.
Abstract:
Displacement of the heart to expose the left circumflex artery (LCX) causes hemodynamic disturbance during off-pump coronary artery bypass grafting (CABG). We applied right heart bypass (RHB) using a heparin-coated centrifugal pump without an oxygenator in an attempt to stabilize the hemodynamics. Five mongrel dogs (15.5-20 kg) were used. Hemodynamic parameters were continuously monitored at a fixed rate of 80 beats/min. The LCX was exposed with the use of an Octopus Tissue Stabilizer. After baseline data were obtained, each dog was placed in the Trendelenburg position. Finally, RHB was established with different pump flows. LCX exposure caused a significant decrease in aortic flow (to 33.1% +/- 13.1% of the baseline value) and arterial mean pressure (to 68.3% +/- 8.5%) (P < 0.001). Trendelenburg positioning caused these values to recover to 57.1% +/- 6.7% and 72.5% +/- 7.7%, respectively. RHB with 50% flow significantly improved the hemodynamic values, although 100% flow significantly increased LAP by 134.8% +/- 19.7% (P < 0.01). Tilting of the canine heart to expose the LCX caused significant deterioration of the hemodynamic values. Trendelenburg positioning was moderately effective, and RHB very effective, in improving the hemodynamics. In a limited number of cases, an appropriate flow of RHB may provide safe hemodynamic assistance during off-pump CABG of the LCX.