Intraluminal coronary shunting preserves regional myocardial perfusion and function.
BACKGROUND
Coronary artery hemostasis during offpump coronary artery bypass (OPCAB) may be achieved with extraluminal coronary occlusion or intraluminal coronary shunting. We sought to determine with a normal porcine beating-heart model whether coronary shunting preserves regional myocardial perfusion and function compared with coronary occlusion.


METHODS
Six pigs (50-60 kg) underwent sternotomy and instrumentation. Two pairs of ultrasonic crystals were placed in the distribution of t h e left anterior descending (LAD) and left circumflex (LCx) arteries for measurement of fractional change in area (FCA), an index of regional contractility. Regional myocardial blood flow (RMBF) was determined with radiolabeled microspheres. Data were recorded for each animal at baseline and after LAD arteriotomy and vascular control with (1) a 1.5-mm intraluminal shunt, (2) proximal occlusion, and (3) proximal and distal occlusion.


RESULTS
One pig experienced ventricular fibrillation during LAD manipulation and was excluded from the study. Data were summarized for the remaining 5 animals. Coronary shunting maintained RMBF and function (FCA) compared with baseline. Proximal occlusion led to 50% (P =.05) and 47% (P =.04) decreases in RMBF and FCA, respectively, in the LAD region. Proximal and distal occlusion led to 55% (P =.03) and 51% (P = 02) decreases in RMBF and FCA, respectively, in the LAD region. There were no significant changes in RMBF or FCA in the LCx (control) region.


CONCLUSIONS
Intraluminal coronary shunting is capable of preserving distal myocardial perfusion and function in a normal porcine heart. Coronary occlusion, in contrast, significantly reduces regional perfusion and function. More frequent use of intracoronary shunting may facilitate OPCAB by minimizing ischemia and hemodynamic compromise.
Sepic
Jerome
J
Division of Cardiac Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts. jsepic@partners.org
Wee
Jon O
JO
Soltesz
Edward G
EG
Laurence
Rita G
RG
Aklog
Lishan
L
D000818:Animals; D006328:Cardiac Catheterization; D001026:Coronary Artery Bypass / Q000379:methods*; D003326:Coronary Circulation / Q000502:physiology*; D005260:Female; D006439:Hemodynamics; D006488:Hemostasis, Surgical / Q000379:methods*; D008297:Male; D009200:Myocardial Contraction / Q000502:physiology*; D017202:Myocardial Ischemia / Q000517:prevention & control; D013552:Swine