A miniature right heart support system improves cardiac output and stroke volume during beating heart posterior/lateral coronary artery bypass grafting.
BACKGROUND
Certain heart manipulations carried out to access anastomotic sites during beating heart coronary artery bypass (OPCAB) compromise hemodynamics, and these risks can affect end-organ perfusion and limit patient selection. Evidence suggests that right heart support (RHS) augments left ventricular preload and provides hemodynamic stability. This study evaluated hemodynamic measures in OPCAB with RHS with respect to individual target vessels and general target distribution groups.


METHODS
Beating heart surgery was performed on 52 patients with left ventricular preload managed with RHS. The average patient age was 69.9 years, and the average ejection fraction was 42.9% +/- 10.9%. Measurements of cardiac output, stroke volume, mean arterial pressure (MAP), heart rate, and cardiac index (CI) were taken at baseline, during each anastomosis with the optimal heart position, and when the RHS was momentarily interrupted prior to heart release. Anastomoses were categorized individually and into posterior/lateral (n = 91) or anterior/right (n = 90) groups and divided into the following output groups based on CI with optimal heart positioning without RHS: group 1 (low output; CI < 1.8), group 2 (marginal output; 1.8 < or = CI < 2.2), group 3 (acceptable output; CI > or = 2.2), and group 4 (output unchanged or increased).


RESULTS
One hundred eighty-one vessels were grafted with an average of 3.5 per patient. Significant reductions in CI, MAP, and stroke volume were observed for all target vessels when RHS was briefly off, especially for posterior and lateral target vessels (12%-26% decrease). In both posterior/lateral and anterior/right target vessel groups, RHS improved CI and MAP in > or = 90% of the anastomoses (groups 1-3). Without RHS, 60% of posterior/lateral and 54% of anterior/right target positions resulted in critically low or marginal output (groups 1 and 2). There was one bypass conversion and no surgical interruptions, intraoperative intra-aortic balloon pump placements, or deaths.


CONCLUSIONS
Augmenting left ventricular preload with RHS improves hemodynamic measures during OPCAB for all target vessel positions and provides critical support in a large number of anastomoses.
Lundell
Dwight C
DC
Banner Heart Hospital, Mesa, Arizona 85206, USA. dlundell@avtek.com
Crouch
John D
JD
D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure / Q000502:physiology; D002302:Cardiac Output / Q000502:physiology*; D001026:Coronary Artery Bypass / Q000379:methods*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006353:Heart-Assist Devices; D006801:Humans; D008297:Male; D008875:Middle Aged; D013318:Stroke Volume / Q000502:physiology