摘要
Background Despite the accepted utility of delayed enhancement MRI in identi fying irreversible myocardial injury,no study has yet assessed its role as a via bility 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 enha ncement MRI would have high diagnostic accuracy in predicting viability and (2) the occurrence of perioperative myocardial necrosis would affect late regional w all motion recovery. Methods and Results Fifty two patients undergoing multive ssel CABG were studied by preoperative and early (day 6) and late (6 months) pos toperative cine MRI for global and regional functional assessment and delayed e nhancement 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%(3 43 of 611) of dysfunctional segments improved contraction by at least 1 grade. W hen all preoperative dysfunctional segments were analyzed, there was a strong co rrelation between the transmural extent of hyper enhancement and the recovery in regional function at 6 months (P< 0.001). Of a total of 96 previously dysfunctional but nonenhancing or minimally hyperenhanci ng myocardial segments that did not improve regional function at 6 months, 35(36 %) demonstrated new perioperative hyperenhancement in the early postoperative M RI scan. Conclusions Delayed enhancement MRI is a powerful predictor of myocar dial viability after surgery, suggesting an important role for this technique in clinical viability assessment.
Background Despite the accepted utility of delayed enhancement MRI in identi fying irreversible myocardial injury,no study has yet assessed its role as a via bility 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 enha ncement MRI would have high diagnostic accuracy in predicting viability and (2) the occurrence of perioperative myocardial necrosis would affect late regional w all motion recovery. Methods and Results Fifty two patients undergoing multive ssel CABG were studied by preoperative and early (day 6) and late (6 months) pos toperative cine MRI for global and regional functional assessment and delayed e nhancement 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%(3 43 of 611) of dysfunctional segments improved contraction by at least 1 grade. W hen all preoperative dysfunctional segments were analyzed, there was a strong co rrelation between the transmural extent of hyper enhancement and the recovery in regional function at 6 months (P< 0.001). Of a total of 96 previously dysfunctional but nonenhancing or minimally hyperenhanci ng myocardial segments that did not improve regional function at 6 months, 35(36 %) demonstrated new perioperative hyperenhancement in the early postoperative M RI scan. Conclusions Delayed enhancement MRI is a powerful predictor of myocar dial viability after surgery, suggesting an important role for this technique in clinical viability assessment.
