A prospective randomized study to evaluate stress response during beating-heart and conventional coronary revascularization.
BACKGROUND
Cardiopulmonary bypass (CPB) is associated with a systemic stress hormonal response, which can lead to changes in hemodynamics and organ perfusion. We examined perioperative stress hormone release in low-risk patients undergoing coronary artery bypass grafting with and without cardiopulmonary bypass.


METHODS
Fifty-two patients undergoing primary coronary artery bypass grafting by the same surgeon were randomly assigned into either on-pump (n = 26) or off-pump (n = 26) groups. The on-pump coronary artery bypass grafting group underwent mildly hypothermic (35 degrees C) pulsatile cardiopulmonary bypass with arterial line filtration. Arterial blood samples were collected preoperatively, at the end of operation, and at 1, 6, and 24 hours postoperatively. Plasma levels of vasopressin and cortisol were measured using radioimmunoassay. Anesthetic management was standardized.


RESULTS
Both groups had similar demographic makeup and extent of revascularization (on-pump coronary artery bypass grafting, 2.8 +/- 1.0 grafts versus off-pump coronary artery bypass grafting, 2.4 +/- 0.9 grafts; p = 0.20). No mortality or major morbidity was observed and there were no crossovers. The cardiopulmonary bypass and aortic cross-clamp times in the on-pump coronary artery bypass grafting group were 63 +/- 24 and 33 +/- 11 minutes, respectively. In both groups there was a similar and significant rise in cortisol and vasopressin levels in the early postoperative phase, with a partial recovery toward baseline values observed at 24 hours postoperatively. Repeated measures analysis of covariance showed no significant difference between the groups with time for both hormones (cortisol, p = 0.40; vasopressin, p = 0.30).


CONCLUSIONS
Despite the avoidance of cardiopulmonary bypass, off-pump coronary artery bypass grafting surgery triggers a systemic stress hormone response that is comparable to conventional surgical revascularization. The neurohormonal environment during beating-heart surgery should be further explored.
Velissaris
Theodore
T
Wessex Cardiothoracic Centre, Southampton General Hospital, Tremona Road, Southampton SO16 6YD, United Kingdom. theo@velissaris.com
Tang
Augustine T M
AT
Murray
Matthew
M
Mehta
Rajnikant L
RL
Wood
Peter J
PJ
Hett
David A
DA
Ohri
Sunil K
SK
D000368:Aged; D015415:Biomarkers; D002315:Cardiopulmonary Bypass / Q000009:adverse effects*; D001026:Coronary Artery Bypass; D047549:Coronary Artery Bypass, Off-Pump; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007036:Hypothermia, Induced; D007431:Intraoperative Complications / Q000097:blood / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000097:blood / Q000209:etiology*; D011446:Prospective Studies; D013312:Stress, Physiological / Q000097:blood / Q000209:etiology*; D018746:Systemic Inflammatory Response Syndrome / Q000097:blood / Q000209:etiology; D014667:Vasopressins / Q000097:blood
D015415:Biomarkers; D014667:Vasopressins; D006854:Hydrocortisone