Thorac Cardiovasc Surg 2014; 62 - OP25
DOI: 10.1055/s-0034-1367102

Microvascular alterations during surgical aortic valve replacement utilizing minimal extracorporeal circulation and conventional cardiopulmonary bypass

P. Donndorf 1, H. Park 1, B. Vollmar 2, A. Alms 3, G. Steinhoff 1, A. Kaminski 1
  • 1Universitäres Herzzentrum Rostock, Klinik und Poliklinik für Herzchirurgie, Rostock, Germany
  • 2Universität Rostock, Institut für Experimentelle Chirurgie, Rostock, Germany
  • 3Universität Rostock, Klinik und Poliklinik für Anästhesiologie und Intensivtherapie, Rostock, Germany

Objectives: Minimal extracorporeal circulation (MECC) systems have been introduced in surgical aortic valve replacement (AVR), offering possible perioperative benefits due to reduced hemodilution and no blood-air interface. Yet, the effects MECC systems on the intraoperative microvascular perfusion in comparison to conventional extracorporeal circulation (CECC) have not been studied so far.

Methods: In the current study we aimed to analyze alterations in microvascular perfusion at four pre-defined time-points (T1-T4) during surgical AVR utilizing Orthogonal polarization spectral imaging (OPS). Twenty patient scheduled for elective AVR were prospectively randomized for being operated utilizing either MECC or CECC. Changes in functional capillary density (FCD), blood flow velocity and vessel diameter were analyzed by a blinded investigator.

Results: After start of the extracorporeal circulation and aortic crossclamping (T2) both groups showed a significant drop of the functional capillary density as compared to the respective baseline values, but with a significantly higher FCD in patients operated with the MECC system (153.1 ± 15.0 cm/cm2 in CECC group vs. 160.8 ± 12.2 cm/cm2 in MECC group, p = 0.034). At T3, in the late phase of cardiopulmonary bypass, the FCD in both groups were still significantly impaired below the baseline value, (153.5 ± 14.6 cm/cm2 in CECC group, p < 0.05 vs. 'T1'; 159.5 ± 12.4 cm/cm2 in MECC group, p < 0.05 vs. 'T1'). Inter-group comparison, however, did not reveal a significant difference of the FCD between the two groups at the time-point T3 (p = 0.071). After termination of the cardiopulmonary bypass at the time-point T4 the FCD recovered in both groups to baseline values. Measurements of red blood cell velocity in post-capillary venules revealed no significant intraoperative changes during surgical AVR utilizing ether CECC or MECC. However, the blood flow velocity tended to be higher in the MECC group at the time-points T2 and T3 (0.542 ± 0.04 mm/s in CECC group at T2 vs. 0.552 ± mm/s in MECC group at T2, p = 0.42; and 0.550 ± 0.04 mm/s in CECC group at T3 vs. 0.554 ± mm/s in MECC group at T3,p = 0.41).

Conclusions: OPS imaging data reveal a certain degree of impairment regarding nutritive microvascular perfusion, represented by the FCD, during surgical AVR. Analysis of changes in the FCD, indicate that reduced hemodilution in MECC does not cause inferior microvascular tissue perfusion compared to conventional ECC during surgical AVR.