Ninety-degree anterior cardiac displacement in off-pump coronary artery bypass grafting: the Starfish cardiac positioner preserves stroke volume and arterial pressure.
OBJECTIVE
In off-pump coronary surgery through sternotomy, exposure of posterior circumflex branches causes circulatory deterioration in both patients and pigs. We assessed cardiac pump function when displacing the pig heart anteriorly with a suction cardiac positioner.


METHODS
Six pigs (+/-80 kg) underwent sternotomy for hemodynamic instrumentation using catheter-tipped manometers and paced at 80 beats/min. Ultrasound flow probes were placed around the aorta and proximal coronary arteries. The heart was retracted anteriorly to 90 degrees with the Starfish cardiac positioner attached to the apex by means of suction (-400 mm Hg). Retraction was guided by cardiac output monitoring.


RESULTS
Anterior displacement to 90 degrees facilitated full exposure of posterior arteries. Stroke volume and mean arterial pressure decreased to 94% +/- 13% (mean +/- SD, p = 0.135) and 95% +/- 13% (p = 0.09) of control values, respectively. Right and left ventricular end-diastolic pressure increased to 129% +/- 37% (p = 0.009) and to 128% +/- 57% (p = 0.235), respectively. Coronary flow remained unchanged. Additional 15-degree head-down positioning increased stroke volume to 113% +/- 17% (p = 0.015) and mean arterial pressure to 113% +/- 25% (p = 0.087) at the expense of further increased right and left ventricular end-diastolic pressure (186% +/- 63%, p < 0.001 and 157% +/- 49%, p < 0.001, respectively).


CONCLUSIONS
When lifting the porcine heart ninety degrees anteriorly, the Starfish cardiac positioner facilitated exposure of posterior branches and, when guided by cardiac output, preserved stroke volume and arterial pressure.
Experimental Cardiology Laboratory, Heart Lung Institute, Heart Lung Center Utrecht, Utrecht University Medical Center, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands. exp.cardio@hli.azu.nl
Paul F
PF
Gründeman
Cees W J
CW
Verlaan
Wim Jan
WJ
van Boven
Cornelius
C
Borst
D000818:Animals; D001794:Blood Pressure; D047549:Coronary Artery Bypass, Off-Pump / Q000295:instrumentation*; D003326:Coronary Circulation; D003971:Diastole; D004867:Equipment Design; D005260:Female; D018475:Head-Down Tilt; D006321:Heart; D006801:Humans; D008297:Male; D013045:Species Specificity; D013314:Stress, Mechanical; D013318:Stroke Volume; D013396:Suction; D034421:Sus scrofa