| Objectives:Previous studies have shown that viable myocardium predicts recovery of left ventricular (LV) dysfunction after revascularization. Our aim was to evaluate the diagnostic value of late gadolinium-enhanced cardiovascular magnetic resonance imaging (LGE-CMR) in predicting cardiac functional improvement of patients with coronary artery disease (CAD) and LV dysfunction who underwent coronary artery bypass grafting (CABG).Methods:From November2009to September2012,63patients with CAD and LV dysfunction referred for first-time isolated CABG in department of adult cardiovascular surgery of our institute were prospectively enrolled, LV functional parameters and scar tissue were assessed by LGE-CMR at baseline and6months after surgery. Patency of grafts was evaluated by computed tomography angiography (CTA)6months post-CABG. Predictors for global functional recovery were analyzed.Results:11patients were excluded, including6with graft failure and5for other reasons, leaving a final study population of52patients. The baseline left ventricular ejection fraction (LVEF) was (32.7±9.2)%, which improved to (41.6±11.0)%6months later. Among all52patients,32had global functional recovery (improved LVEF by≥5%), while20had not (improved LVEF by<5%). Based on the American Heart Association (AHA)17-segment format, a total of884segments were analyzed, of which688(77.8%) segments were determined to be dysfunctional preoperatively. Six months after CABG,305(44.3%) segments showed functional improvement. In viable and normal segments (≤50%LGE),291/467(62.3%) improved contraction, while in scar segments (>50%LGE), only14/221(6.3%) improved contraction post-surgery (P<0.001). Multivariate logistic regression analysis showed that the most significant predictor for global functional recovery was the number of scar segments (Odds Ratio2.864,95%Confidence Interval1.172-6.996, P=0.021). Receiver Operator Characteristic (ROC) analysis demonstrated that≤4scar segments predicted global functional recovery with a sensitivity and specificity of85.0%and87.5%, respectively [(area under curve, AUC)=0.91, P<0.001). Comparison of ROC curves also indicated that scar tissue was superior to viable myocardium in predicting cardiac functional recovery (AUC0.91versus0.65, P<0.001). After multivariate analysis, patients were divided into two groups (<4scar segments, n= 31and>4scar segments, n=21) according to the number of scar segments. The median follow-up time was14.0months (range,6-38months) and no patients lost to follow-up. During follow-up time, one patient suffered from nonfatal myocardial infarction in patients with≤4scar segments. While in patients with>4scar segments, one patient had rehospitalization for heart failure, one had recurrence of angina pectoris, two patients had ventricular arrhythmia. The mid-term cardiovascular events (CVEs)-free survival rate was significantly higher in patients with≤4scar segments than in patients with>4scar segments (96.8%versus81.0%, log-rank test, P=0.020).Conclusions:1.Our findings indicated that scar segments based on LGE-CMR is an independent predictor of cardiac functional recovery in patients with impaired LV function who underwent surgical revascularization.2. Based on AHA17-segment format, patients with≤4scar segments could improve global LV function significantly post-fevascularization, while patients with more such segments did not.3. These observations may be helpful for cardiovascular surgeons to determine which patients are most likely to benefit from surgical revascularization. Objectives:Left ventricular ejection fraction (LVEF) and left ventricular (LV) volumes have been shown to be significant predictors of cardiovascular events (CVEs) in patients with coronary artery disease (CAD) and chronic myocardial infarction (CMI) in recent years. With the rapid development of late gadolinium-enhanced cardiovascular magnetic resonance imaging (LGE-CMR), precise delineation of infarct size and hemi-quantitative measurement of myocardial scar is now possible. Previous studies have shown that viable myocardium can predict improvement of LV dysfunction as well as long-term prognosis after revascularization therapy. Information on the relative merits of myocardial scar tissue to predict outcome in patients undergoing coronary artery bypass grafting (CABG) is lacking. The purpose of this study was to explore the relationship between myocardial scar assessed by LGE-CMR and adverse CVEs in CABG-treated patients with CMI.Methods:A total of140patients with CAD and CMI who underwent CABG in the department of adult cardiovascular surgery of our institute between April2009and May2013were included. LGE-CMR was performed in all patients before surgery. LV function and LV volumes were measured. Scar tissue was derived from LGE-CMR using17-segment analysis suggested by American Heart Association (AHA). The outcome of surgery was documented and follow-up was carried out periodically. In combination with other potential risk factors, Cox proportional hazards analysis was used and conducted to explore the relationship between myocardial scar and adverse CVEs post-surgery.Results:Six patients lost to follow-up were excluded from the present study and leaving a final population of134patients. Intra-aortic balloon pump (IABP) therapy was employed in one patient who suffered from low cardiac output syndrome (LCOS). Two death occurred after CABG due to systemic circulation failure. Eleven patients (8.3%) suffered from CVEs during a mean follow-up time of (29.2±13.0) months, including4rehospitalizations for heart failure,3recurrence of angina pectoris,2ventricular arrhythmia and2nonfatal myocardial infarction Patients were divided into two groups according to whether or not CVEs occurred (patients with CVEs, n=14and patients without CVEs, n=120). Univariate analysis showed that LVEF、Left ventricular end-diastolic volume index (LVEDVI)、 Left ventricular end-systolic volume index (LVEDVI)、 spatial extent、 the number of scar segments、 late gadolinium enhancement (LGE) score、 New York Heart Association (NYHA) function class were significantly associated with CVEs after CABG. After adjustment for multiple confounders (such as age, sex, comorbidities etc), Cox proportional hazards analysis revealed that only the number of scar segments as determined by LGE-CMR appeared significantly related with CVEs post-CABG (hazard ratio [HR]2.783,95%confidence interval [CI]1.116-6.939, P=0.028). Receiver Operator Characteristic (ROC) analysis indicated that>6scar segments can predict CVEs after CABG with a sensitivity and specificity of78.6%and91.7%, respectively (area under curve, AUC=0.915, P<0.001). After Cox proportional hazards analysis, all patients were divided into two groups (<6scar segments, n=113and≥6scar segments, n=21) according to the number of scar segments. Kaplan-Meier analysis demonstrated that CVEs-free survival rate was significantly higher in patients with<6scar segments than those with≥6scar segments (97.3%versus47.6%, log-rank test, P<0.001).Conclusions:1. The number of scar segments on LGE-CMR is the most significant predictor associated with CVEs in patients with CAD and CMI after CABG.2. The17-segment analysis recommended by AHA demonstrated that patients with≥6scar segments have a higher CVEs rate after surgery.3. Larger clinical trials are needed to prove the certain association between myocardial scar and adverse CVEs in patients with CMI after CABG. Objectives:Although coronary artery bypass grafting (CABG) has been shown to be an effective treatment for coronary artery disease (CAD) and left ventricular (LV) dysfunction, patients with congestive heart failure (CHF) as well as LV enlargement are known to have inferior prognosis. Previous published studies have demonstrated that these patients could benefit from CABG combined with surgical ventricular reconstruction (SVR). However, a continuing controversy concerning the best management regimen for patients with CAD and CHF still exists between CABG+SVR and isolated CABG (I-CABG). The purpose of this study was to evaluate whether CABG combined with SVR leads to recovery of function and improvement of prognosis compared withI-CABG for patients withLV aneurysm and CHF.Methods:We conducted a retrospective study comparing patients with CHF and left ventricular ejection fraction (LVEF)≤35%(measured by cardiovascular magnetic resonance imaging) who received either I-CABG or CABG+SVR in the department of adult cardiovascular surgery of our institute from April2009to June2013. Patients who underwent CABG+SVR were compared with those control patients who met criteria for CABG+SVR by ventriculogram or late gadolinium-enhanced cardiovascular magnetic resonance imaging (LGE-CMR) but only received I-CABG. Baseline characteristic of all patients, operative data, postoperative outcomes and follow-up were collected by chart review. The primary end points were cardiovascular events (CVEs) occurred during follow-up, including death (cardiac or non-cardiac), rehospitalization for CHF, ventricular arrhythmia (VA), recurrent angina pectoris, nonfatal myocardial infarction. The secondary end points included perioperative complications, improvement in LVEF/left ventricular end-diastolic diameter (LVEDD), and New York Heart Association (NYHA) class during follow-up.Results:A total of120patients who met criteria undergoing I-CABG (n=60) versus CABG+SVR (n=60) were included in the present study. There were104male and16female patients with a mean age at operation of58.2±7.6years. I-CABG patients matched very well with those who underwent CABG+SVR and there was no significant difference in all baseline characteristics or LGE-CMR data between these two groups. The CABG+SVR patients had significantly longer operation time (226.2±48.4versus246.4±51.4, P=0.028), cardiopulmonary bypass time (101.5±24.2versus118.7±36.6, P=0.003) as well as cross-clamp time (66.4±18.4versus76.2±21.6, P=0.009) than I-CABG patients, but fewer distal anastomoses (3.4±0.8versus3.0±0.9, P=0.004). Intra-aortic balloon pump (IABP) therapy was used in3patients in I-CABG group and4patients in CABG+SVR group (P=1.000). Death occurred in2patients who underwent I-CABG and the operative mortality was similar between these two groups (3.3%versus0.0%, P=0.476). The mean follow-up time was (28.0±14.8) months and2patients were lost to follow-up. The follow-up success rate was98.3%. LVEF (by Echocardiography) improvement≥5%was observed in63.2%of I-CABG patients compared with86.4%for CABG+SVR patients (P=0.004). The I-CABG patients experienced more rehospitalizations for CHF than CABG+SVR patients (19.3%versus6.8%, P=0.045) and78.9%of I-CABG versus93.2%of CABG+SVR patients improved to NYHA class I or II (P=0.026). Kaplan-Meier analysis indicated that the3-year CVEs-free survival rate was significantly lower in I-CABG patients than CABG+SVR patients (75.9%vs91.7%, log-rank test, P=0.009).Conclusions:The present study compared the efficacy of I-CABG with that of CABG+SVR in patients with CAD and CHF. Based on our outcomes, we conclude that1. CABG+SVR resulted in decreased symptoms, fewer rehospitalizations for CHF and better improvements in LVEF as well as NYHA class.2. The additional SVR procedure should be offered to appropriately selected patients with LV enlargement and CHF in whom SVR still holds its ground.3. Nevertheless, multicenter, prospective, randomized controlled clinical trials are needed to further compare these two surgical strategies including I-CABG and CABG+SVR. |
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