Transient ischemia does not limit subsequent ischemic regional dysfunction in humans: a transesophageal echocardiographic study during minimally invasive coronary artery bypass surgery.
OBJECTIVE
This study sought to assess the effects of sequential coronary artery occlusion during minimally invasive coronary artery bypass graft surgery (CABG) on hemodynamic variables and left ventricular systolic function by means of transesophageal echocardiography (TEE).


BACKGROUND
Clinical and experimental studies suggest a protective effect of ischemic preconditioning in patients with acute coronary syndromes. However, the effect of repetitive myocardial ischemia on myocardial mechanical function in humans is not completely understood.


METHODS
Seventeen patients with left anterior descending coronary artery (LAD) stenosis > or =70% and normal rest left ventricular systolic function referred for minimally invasive CABG underwent intraoperative TEE for assessment of regional left ventricular wall motion and measurement of hemodynamic variables at baseline (baseline 1), during a 5-min coronary occlusion (occlusion 1), after a 5-min reperfusion period (baseline 2) and a during a second coronary occlusion during bypass anastomosis (occlusion 2).


RESULTS
Left ventricular wall motion score (LVWMS) increased significantly from baseline (16.0) to occlusion 1 (21.4+/-3.1 [mean +/- SD], p < 0.05) and occlusion 2 (21.8+/-3.1, p < 0.05). No difference in LVWMS was noted between occlusions 1 and 2. Pulmonary artery systolic pressure increased significantly from baseline (25+/-6 mm Hg) to occlusion 1 (32+/-7 mm Hg, p < 0.05) and occlusion 2 (33+/-6 mm Hg, p < 0.05). Pulmonary artery diastolic pressure also increased significantly from baseline (12+/-4 mm Hg) to occlusion 1 (16+/-4 mm Hg, p < 0.05) and occlusion 2 (16+/-4 mm Hg, p < 0.05). No significant differences in pulmonary artery pressures were noted between occlusions 1 and 2.


CONCLUSIONS
Ischemic dysfunction was precipitated by the 5-min LAD occlusion, as shown by the increase in LVWMS and pulmonary artery pressure. However, a 5-min coronary occlusion and the resulting ischemia do not alter regional left ventricular systolic function during subsequent ischemia in humans.
Malkowski
M J
MJ
Department of Anesthesia, Allegheny General Hospital, Allegheny University of the Health Sciences, MCP-Hahnemann School of Medicine, Pittsburgh, Pennsylvania 15212-4772, USA. Malkowsk@pgh.auhs.edu
Kramer
C M
CM
Parvizi
S T
ST
Dianzumba
S
S
Marquez
J
J
Reichek
N
N
Magovern
J A
JA
D000368:Aged; D001794:Blood Pressure; D001026:Coronary Artery Bypass; D017548:Echocardiography, Transesophageal; D005260:Female; D006801:Humans; D019157:Ischemic Preconditioning, Myocardial; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000517:prevention & control*; D011651:Pulmonary Artery / Q000502:physiology; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000517:prevention & control*