"Polarizing" microplegia improves cardiac cycle efficiency after CABG for unstable angina.
BACKGROUND
Myocardial protection during coronary artery bypass grafting (CABG) for unstable angina (UA) still represents a major challenge, ought to the risk for further ischemia/reperfusion injury. Few studies investigate the biochemical, hemodynamic and echocardiographic results of microplegia (Mic) in UA.


METHODS
Eighty UA-patients undergoing CABG were randomized to Mic (Mic-Group) or standard 4:1 blood Buckberg-cardioplegia (Buck-Group). Troponin-I and lactate were sampled from coronary sinus at reperfusion (T1), and from peripheral blood preoperatively (T0), at 6 (T2), 12 (T3) and 48 (T4) hours. Cardiac index (CI), indexed systemic vascular resistances (ISVR), Δp/Δt, cardiac cycle efficiency (CCE), and central venous pressure (CVP) were collected preoperatively (T0), and since Intensive Care Unit (ICU)-arrival (T1) to 24h (T5). Echocardiographic E-wave (E), A-wave (A), E/A, peak early-diastolic TDI-mitral annular-velocity (Ea), and E/Ea investigated the diastolic function and Wall Motion Score Index (WMSI) the systolic function, preoperatively (T0) and at 96h (T1).


RESULTS
Mic-Group showed lower troponin-I and lactate from coronary sinus (p=.0001 for both) and during the postoperative course (between-groups p=.001 and .0001, respectively). WMSI improved only after Mic (time-p=.001). Higher CI Δp/Δt and CCE (between-groups p=.0001), with comparable CVP and ISVR (p=N.S.) were detected after Mic. Diastolic function improved in both groups, but better after Mic (between-groups p=.003, .001, and .013 for E, E/A, and Ea, respectively). Mic resulted in lower transfusions (p=.006) and hospitalization (p=.002), and a trend towards lower need/duration of inotropes (p=.04 and p=.041, respectively), and ICU-stay (p=.015).


CONCLUSIONS
Microplegia attenuates myocardial damage in UA, reduces transfusions, improves postoperative systo-diastolic function, and shortens hospitalization.
Division of Cardiac Surgery, University of Verona Medical School, Italy. frankono@libero.it
Francesco
F
Onorati
Francesco
F
Santini
Rajesh
R
Dandale
Grazia
G
Ucci
Kostantinos
K
Pechlivanidis
Tiziano
T
Menon
Bartolomeo
B
Chiominto
Alesssandro
A
Mazzucco
Giuseppe
G
Faggian
D000368:Aged; D000789:Angina, Unstable / Q000503:physiopathology* / Q000601:surgery*; D001026:Coronary Artery Bypass / Q000379:methods*; D005260:Female; D006324:Heart Arrest, Induced / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000503:physiopathology / Q000517:prevention & control*; D011446:Prospective Studies; D016037:Single-Blind Method; D016896:Treatment Outcome