Circulating Microemboli after Composite Replacement or Valve-sparing Aortic Root Surgery

Abstract

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 O₂ at 9 l/min. Results: 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.

Key words

Aorta - Valves - Aneurysm - Microembolism

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