Value of delayed-enhancement cardiovascular magnetic resonance imaging in predicting myocardial viability after surgical revascularization.
BACKGROUND
Despite the accepted utility of delayed-enhancement MRI in identifying irreversible myocardial injury, no study has yet assessed its role as a viability tool exclusively in the setting of coronary artery bypass surgery (CABG), and no study has repeated delayed-enhancement MRI late after revascularization. In a clinical trial in which patients underwent CABG by either the off-pump or on-pump surgical technique, we hypothesized that (1) preoperative delayed-enhancement MRI would have high diagnostic accuracy in predicting viability and (2) the occurrence of perioperative myocardial necrosis would affect late regional wall motion recovery.


RESULTS
Fifty-two patients undergoing multivessel CABG were studied by preoperative and early (day 6) and late (6 months) postoperative cine MRI for global and regional functional assessment and delayed-enhancement MRI for assessment of irreversible myocardial injury. Preoperatively, 611 segments (21%) had abnormal regional function, whereas 421 segments (14%) showed evidence of hyperenhancement. At 6 months after revascularization, 57% (343 of 611) of dysfunctional segments improved contraction by at least 1 grade. When all preoperative dysfunctional segments were analyzed, there was a strong correlation between the transmural extent of hyperenhancement and the recovery in regional function at 6 months (P<0.001). Of a total of 96 previously dysfunctional but nonenhancing or minimally hyperenhancing myocardial segments that did not improve regional function at 6 months, 35 (36%) demonstrated new perioperative hyperenhancement in the early postoperative MRI scan.


CONCLUSIONS
Delayed-enhancement MRI is a powerful predictor of myocardial viability after surgery, suggesting an important role for this technique in clinical viability assessment.
Selvanayagam
Joseph B
JB
University of Oxford Centre for Clinical Magnetic Resonance Research, University of Oxford, John Radcliffe Hospital, Oxford, UK.
Kardos
Attila
A
Francis
Jane M
JM
Wiesmann
Frank
F
Petersen
Steffen E
SE
Taggart
David P
DP
Neubauer
Stefan
S
D000368:Aged; D015331:Cohort Studies; D003287:Contrast Media / Q000008:administration & dosage*; D001026:Coronary Artery Bypass; D047549:Coronary Artery Bypass, Off-Pump; D005260:Female; D005500:Follow-Up Studies; D019786:Gadolinium DTPA / Q000008:administration & dosage*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D015428:Myocardial Reperfusion Injury / Q000175:diagnosis* / Q000473:pathology / Q000517:prevention & control; D009206:Myocardium / Q000473:pathology*; D009336:Necrosis; D015588:Observer Variation; D011184:Postoperative Period; D016032:Randomized Controlled Trials as Topic
D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA