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Circulating microemboli after composite replacement or valve-sparing aortic root surgery
A Nötzold1, T Gerriets, J Eggers
1Department of Cardiac Surgery and Neurology, Medical University of Lübeck, Germany. noetzold@medinf.mu-luebeck.de
Background:
The purpose of this study was to determine whether microembolic signals (MES) occur after valve-sparing operations on the aortic root. One of the advantages of these procedures relates to the freedom of macroemboli without anticoagulation. Whether this holds true for circulating microemboli has not yet been verified.
Methods:
For comparison, 8 male patients (mean age: 51.8 +/- 12.8 years) were investigated 20.5 +/- 8.4 months after implantation of a mechanical composite graft (group I) and 9 female and 7 male patients (mean age 55.0 +/- 13.4 years) 23.5 +/- 20.0 months after valve-sparing replacement of the aortic root (group II). The middle cerebral artery was insonated for 2 periods of 30 min, breathing room air or O 2 at 9 l/min.
Result:
Breathing room air, the amount of MES was considerably smaller in group II (0.94 +/- 1.95 vs. 56.1 +/- 58.9 per 30 min, p = 0.006). The difference was less pronounced (0.5 +/- 1.3 vs. 28.9 +/- 42.6 per 30 min, p = 0.009) breathing oxygen. Breathing oxygen reduced MES significantly in group I (p < 0.05) but not in group II (p > 0.05).
Conclusions:
Aortic valve-sparing operations induce MES at a significantly lower rate than composite aortic valve replacement using a mechanical valve.
Insights
Valve-sparing aortic root surgery generates fewer microembolic signals (MES) compared to mechanical valve replacement. This finding suggests a safer profile for valve-sparing procedures regarding microemboli.
Area of Science:
- Cardiovascular Surgery
- Neurology
- Biomedical Engineering
Background:
- Aortic root surgery aims to preserve the native valve, potentially avoiding anticoagulation.
- The risk of microemboli after valve-sparing aortic root operations remains unquantified.
- Mechanical valve replacement is associated with macroemboli risks, necessitating anticoagulation.
Purpose of the Study:
- To investigate the occurrence of microembolic signals (MES) following valve-sparing aortic root operations.
- To compare MES rates between valve-sparing surgery and mechanical composite graft replacement.
- To assess the impact of oxygen breathing on MES in both surgical groups.
Main Methods:
- Two patient groups were compared: mechanical composite graft (n=8) and valve-sparing aortic root replacement (n=16).
- Middle cerebral artery was monitored for MES during two 30-minute periods.
- Patients underwent monitoring while breathing room air and 9 L/min oxygen.
Main Results:
- Significantly fewer MES were detected in the valve-sparing group (0.94/30 min) compared to the mechanical graft group (56.1/30 min) breathing room air (p=0.006).
- Similar differences persisted during oxygen breathing (0.5/30 min vs. 28.9/30 min, p=0.009).
- Oxygen breathing reduced MES in the mechanical graft group (p<0.05) but not in the valve-sparing group (p>0.05).
Conclusions:
- Aortic valve-sparing operations result in a substantially lower rate of microembolic signals compared to mechanical aortic valve replacement.
- These findings suggest valve-sparing surgery may offer a reduced risk of microembolic events.
- Further research is warranted to fully elucidate the embolic profile of different aortic root repair strategies.