Abstract
Background: The sympathoadrenal and the renin-angiotensin system (RAS) are involved in blood
pressure regulation. They are known to be activated during cardiac surgery. We investigated
the influence of preoperative RAS-blockade using angiotensin-converting-enzyme inhibitors
(ACEI) on hemodynamic variables and on the perioperative need for exogenous catecholamines.
Methods: 240 patients undergoing coronary artery bypass grafting (CABG) or valve surgery were
divided into three matched groups (group A: pre- and postoperative ACEI; group B:
ACEI only pre-, not postoperatively; group C: no ACEI). In these three groups we analyzed
hemodynamic variables, the need for catecholamines and the incidence of a “post-perfusion
syndrome" or systemic inflammatory response syndrome (SIRS) with impaired microcirculation.
Results: There were significant differences in the intra- and postoperative need for catecholamines
in groups A and B compared to C (intraop. A: 35 %, B: 35 %, C: 15 %; postop. A: 21.2
%, B: 16.2 %, C: 10 %) (p < 0.05). In the ACEI groups (A and B) there were 9 patients
with a postoperative SIRS, only 2 cases in group C. Furthermore 4 patients of group
B suffered from disturbances of the intestinal microcirculation postoperatively. Conclusions: Long-term ACEI treatment before cardiac surgery raises the perioperative need for
catecholamines. Patients with preoperative long-term use of ACEI who do not receive
ACEI postoperatively face an increased risk of impaired microcirculation. The inhibition
of angiotensin-ll (AT II) generation causes the vasodilatatory effects of ACEI, and
could be one reason for a post-perfusion syndrome or a SIRS.
Key words
Angiotensin converting enzyme inhibitors - Postperfusion syndrome - SIRS - CAGB -
Microcirculation
