Aims: 

Cardiac tamponade (CT) is a life threatening condition that is caused by sudden or gradual compression of the heart. The circulatory redistribution following CT leads to severe gastrointestinal (GI) microcirculatory impairment and subsequent inflammatory complications after resuscitation. We hypothesized that complement activation plays main roles in the development of these changes, and therefore our aim was to characterize the effects of C5a antagonist (C5aA) treatment on GI microcirculatory changes in a large animal model of CT.

Methods: 

In anaesthetized, ventilated and thoracotomized minipigs (n=7) CT was induced for 60 min by intrapericardial administration of colloid solution, meanwhile the mean arterial pressure (MAP) was kept between 40–45 mmHg. Group 2 (n=6) was treated with C5a-A at the 45^th minute of PT. Sham operated group served as control (n=6). Macrohemodynamic changes were monitored for 240 min, plasma big endothelin (bigET; ELISA) was measured from blood samples. The microcirculation of the small intestinal mucosa was recorded by intravital video-microscopy (Cytoscan A/R). Patterns of microperfusion and red blood cell velocity (RBCV) changes were determined before PT, before the administration of C5aA and at the end of post-tamponade phase.

Results: 

During CToscillating microperfusion has been observed, accompanied by reduced RBCV. After relieving CT the MAP decreased despite an increased bigET level, while cardiac output was normalized. The C5aA treatment decreased the oscillatory pattern of microperfusion and significantly increased RBCV (320±48 vs 650±11 mm/s) and it also reduced the plasma bigET concentration (5.2±3.8 vs 26±0.8 fmol/ml).

Conclusion: 

Elevation of plasma bigET level is a significant factor in the development of GI microcirculatory disturbances following CT. C5aA treatment is effectively modulates bigET changes and the GI complications of CT.

Support: 

ETT 442/2009, OTKA K75161; TÁMOP4.2.1; TÁMOP-4.2.2; TÉT JP 16/09