Reduction of Microembolic Signals with a Single-Clamp Strategy in Coronary Artery Bypass Surgery: A Pilot Study
Background: Neurologic deficits are perhaps the most feared form of adverse outcome following cardiac surgery. Aortic trauma generates emboli and hence harbors the potential for neurocognitive injury. The single aortic clamp strategy of coronary artery bypass grafting (CABG) aims at reducing aortic manipulation. We hypothesized that this strategy will lead to a reduction in the number microembolic signals (MES) evaluated by transcranial Doppler (TCD), a surrogate measure of cerebral embolism.
Methods: This pilot study was based on a prospective analysis of 22 patients in whom CABG was performed either with a single aortic clamp (SC group) or with a conventional multiple aortic side-clamp technique (MC group). The 2 groups did not differ with respect to mean age (60 ± 6 years versus 65 ± 8 years, not statistically significant [NS]) or EuroSCORE (2.1 ± 1.5 versus 2.9 ± 2, P = NS). The neurocognitive evaluation was based on the mini-mental state examination (MMSE). The preoperative MMSE values for the SC and MC groups were similar (29.5 ± 0.5 and 29.2 ± 1, respectively; P = NS).
Results: The total number of solid-particle embolization signals secondary to aortic manipulation was lower in the SC group than in the MC group (72 ± 28 versus 127 ± 69, P = .02). Neurocognitive performance was moderately reduced in both groups compared with preoperative values. This reduction was more pronounced in the MC group than in the SC group (22.2 ± 4.1 versus 25.3 ± 1.6, P = .02). One patient in the MC group had a reversible ischemic neurologic deficit (P = NS). There were no deaths or perioperative myocardial infarctions in either group.
Conclusions: The single-clamp CABG strategy led to a reduction in MES, indicating a less pronounced embolic burden than with the conventional side-clamp CABG strategy. This strategy translated into a better performance in postoperative neurocognitive testing in the SC group of patients.
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