Prediction of long-term segmental and global functional recovery of hibernating myocardium after revascularisation based on low dose dobutamine and late gadolinium enhancement cardiovascular magnetic resonance

Abstract

BackgroundThis study sought to evaluate the relation between long-term segmental and global functional outcome after revascularisation in patients with chronic ischaemic left ventricular dysfunction (LVD) and baseline markers of viability: late gadolinium enhancement (LGE) transmurality and contractile reserve (CR).MethodsForty-two patients with chronic ischaemic LVD underwent low-dose dobutamine- (LDD) and late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) before surgical or percutaneous revascularisation. Regional and global left ventricular (LV) functions and LGE were repeatedly assessed 6 ± 1 and 35 ± 6 months after revascularisation. In total, 319 at baseline dysfunctional and successfully revascularised segments were available for statistical analysis.ResultsThe likelihood of long-term functional improvement was directly related to the presence of CR and inversely related to both the LGE and the degree of contractile dysfunction at baseline. The time course of functional improvement was protracted, with significantly more delay in segments with more extensive LGE (p = 0.005) and more severe contractile dysfunction at baseline (p = 0.002). The presence of CR was the predictor of earlier functional improvement (p < 0.0001). Using a definition of viable segment as a segment without any LGE or with any LGE and producing CR during LDD stimulation, ≥55% of viable segments from all dysfunctional and revascularised segments in a patient was the only independent predictor of significant improvement (≥5%) in the left ventricular ejection fraction (LVEF) after revascularisation, with a 72% sensitivity and an 80% specificity (AUC 0.76, p = 0.014). Reverse LV remodelling was observed in patients who had a significant amount of viable myocardium successfully revascularised.ConclusionsIn patients with chronic ischaemic LVD, improvement of dysfunctional but viable myocardium can be considerably delayed. Both the likelihood and the time course of functional improvement are related to the LGE, CR and the degree of contractile dysfunction at baseline. At 35 ± 6 months after revascularisation, patients with ≥55% of viable segments from all dysfunctional and revascularised segments significantly improve LVEF and experience reverse LV remodelling. A combination of LDD–CMR and LGE–CMR is a simple and powerful tool for identifying which patients with impaired LV function will benefit from revascularisation.

Ischemic Mitral Regurgitation: Abnormal Strain Overestimates Nonviable Myocardium

“…Prior studies demonstrate that LV segments with 50–75% transmural infarct have a 10% chance of functional recovery, which reduces to zero for >75% infarct transmurality [9, 23, 24]. We can apply this data to our findings.…”

Utility of cardiac magnetic resonance for evaluation of mitral regurgitation prior to mitral valve surgery

“…However, a wide array of data has shown MR improvement to be linked to LV reverse remodeling (57)(58)(59). In this regard, the predictive utility of viability assessment via CMR is well established: transmural extent of viable myocardium on CMR is well known to predict LV reverse remodeling following surgical or percutaneous (PCI) revascularization (60). For example, among a cohort of 50 CAD patients undergoing elective coronary revascularization, Kim et al showed that dysfunctional but viable myocardium on pre-procedural DE-CMR predicted post-revascularization recovery of LV function (61).…”

“…For example, among a cohort of 50 CAD patients undergoing elective coronary revascularization, Kim et al showed that dysfunctional but viable myocardium on pre-procedural DE-CMR predicted post-revascularization recovery of LV function (61). Other studies have shown viability assessment via DE-CMR to predict reduction in LV chamber size among patients undergoing elective coronary bypass graft surgery, as well as among patients undergoing PCI (60,62,63). Of interest, absence of viable myocardium within the mitral apparatus has been shown to stratify likelihood of MR following acute MI, suggesting this approach may predict longitudinal risk for MR in post-MI patients being considered for coronary revascularization (21).…”

Integrative Cardiac Reserve

“…Methods to monitor this part of the myocardium and its recovery of function are needed. Cardiovascular magnetic resonance (CMR) with its high spatial resolution could provide qualitative and quantitative, global and regional information on myocardial anatomy and function [42] . In combination with a gadolinium-based contrast agent, CMR allows an accurate quantification of the myocardial scar [43] and predicts the likelihood of functional recovery after revascularization [44,45] .…”

“…At 35 ± 6 months after revascularization, patients with ≥ 55% of viable segments from all dysfunctional and revascularized segments had significantly improved LV ejection fraction and experienced reverse LV remodeling. A combination of low-dose dobutamine CMR and late gadolinium enhancement CMR is a simple and powerful tool for identifying which patients with impaired LV function will benefit from revascularization [49] .…”