Central and Peripheral Circulation Differ during Off-Pump Coronary Artery Bypass Grafting.

BACKGROUND

Off-pump coronary artery bypass grafting (OPCAB) is an alternative to on-pump coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB). During OPCAB, the temporary use of an intracoronary shunt and inotropic medication or catecholamines should keep the central hemodynamics constant. Nevertheless, the need for conversion to on-pump CABG often occurs unexpectedly, most likely due to circulation instability. Circulation instability can appear first in peripheral body parts; therefore, peripheral microcirculation might serve as a predictor for the upcoming conversion to on-pump CABG. We investigated the impact of coronary artery ligation and shunt insertion during OPCAB on cutaneous microcirculation (cLDP) with Laser Doppler Perfusion Technology and transcutaneous oxygen partial pressure ( ).

METHODS

In a pig model of OPCAB, peripheral circulation was evaluated after cLDP (N = 17) and (N = 6) monitoring. Systolic, diastolic, and mean arterial pressure were also observed to prove the independence of perfusion measurement results from hemodynamic parameters.

RESULTS

Ligation time during cLDP and monitoring were 101 49 s and 83 33 s, respectively. Shunt time was 11 3 min during cLDP and 13 2 min during measurement. Ligation of the left anterior descending coronary artery (LAD) reduced cLDP significantly to 88 14% ( = 0.007) and to 71 25% ( = 0.038). Inserting a temporary shunt into the LAD significantly improved cLDP ( = 0.006) and ( = 0.015) compared to ligation. cLDP was restored to 99%, and was restored to 91% of the baseline level before ligation. All hemodynamic parameters remained stable and did not change significantly during OPCAB.

CONCLUSIONS

Although hemodynamic parameters stayed constant, peripheral microcirculation was influenced markedly during OPCAB. Inserting a temporary shut into the LAD leads to a complete normalization of peripheral microcirculation, regarding evaluation by cLDP and .