Summary Coronary artery disease (CAD) associated with left ventricular systolic dysfunction is a condition related to poor prognosis. There is a lack of robust evidence in many aspects related to this condition, from definition to treatment. Ischemic cardiomyopathy is a spectrum ranging from stunned myocardium associated with myocardial fibrosis to hibernating myocardium and repetitive episodes of ischemia. In clinical practice, relevance lies in identifying the myocardium that has the ability to recover its contractile reserve after revascularization. Methods to evaluate cellular integrity tend to have higher sensitivity, while the ones assessing contractile reserve have greater specificity, since a larger mass of viable myocytes is required in order to generate contractility change. Since there are many methods and different ways to detect viability, sensitivity and specificity vary widely. Dobutamine-cardiac magnetic resonance with late gadolinium enhancement has the best accuracy is this setting, giving important predictors of prognostic and revascularization benefit such as scar burden, contractile reserve and end-systolic volume index. The latter has shown differential benefit with revascularization in some recent trials. Finally, authors discuss interventional procedures in this population, focusing on coronary artery bypass grafting and evolution of evidence from CASS to post-STICH era.
Background
The evaluation of coronary disease by SYNTAX score I (SSI) is used to grade coronary complexity. Following SSI, two other scores were developed: SYNTAX score II (SSII) and residual SYNTAX score (rSS). Nevertheless, there is still a lack of evidence about the prognostic significance of these scores among patients undergoing CABG.
Purpose
Our aim was to evaluate the relation of the SSI, SSII and rSS score with outcomes in a long-term follow-up after elective CABG.
Methods
This is a single center, registry-based study. Baseline SSI was calculated from patients undergoing CABG by interventional cardiologists. SSI results were considered as usual: <23, 23–32 and >32. SSII and rSRR were then calculated and categorized in tertiles: <21.4, 21.4–29.4 and >29.4 for SSII and 0, 1–5 and >5 for rSS. Primary outcome was a composite of overall death, myocardial infarction, additional revascularization, or stroke (MACCE).
Results
Data were obtained from 559 patients. Median follow-up was 6 years (IQR: 4.9–9.8) and 170 events were documented. The Kaplan-Meier curves (figure 1) showed significant differences of MACCE in higher SSI, SSII and rSS (p=0.039, 0.033, <0.001 respectively). After multivariate adjustment, rSS, ejection fraction (EF) and age were found to be independent predictors of MACCE (p<0.001, 0.034 and 0.006, respectively).
Figure 1
Conclusion
In this sample SSI, II and residual were associated with the occurrence of events. However, just the rSS remained an independent predictor of MACCE together with age and EF.
Background
T1 mapping is a magnetic resonance imaging (MRI) technique that enables the identification of myocardial structural changes during acute ischemic injury. However, it is not known whether these structural changes are present in patients with chronic effort induced ischemia.Thus, we sought to document the possible T1 mapping changes in chronic coronary artery disease (CAD) patients with documented myocardial ischemia.
Methods
Multivessel CAD patients from MASS V Trial with indication of myocardial revascularization, were evaluated for the presence of ischemia by myocardial scintigraphy. MRI with T1 mapping was performed in all patients. Based on the results of the scintigraphy, the myocardial segments were identified as ischemic and non-ischemic segments. The corresponding segments of scintigraphy and MRI were compared in relation to native T1 map (NT1), post-contrast T1 (CAT1) and extracellular volume (ECV).
Results
Of the 720 myocardial segments analyzed, there were 161 ischemic and 559 non-ischemic segments. Comparing ischemic vs non-ischemic segments, respectively, NT1 was 1022.7 (980.0–1052.0) versus 1029.3 (985.0–1066.3), p=0.57, ECV results were 25.4 (24.0–28.1) versus 26.4 (25.3–29.9), p=0.75 and CAT1 results were 492 (461.9–515.4) versus 488 (469.2–521.7), p=0.09. Myocardial segments supplied by obstructive coronary arteries were compared to those supplied by non-obstructive coronary arteries in relation to NT1 and ECV. NT1 values in obstructive and non-obstructive territories were, respectively, 1024.7 (998.5–1043.5) versus 1036.8 (1008.6–1046.9), p=0.30 and ECV results were 26.8 (24.4–29.9) versus 26.8 (24.4–30.0), p=0.90.
Conclusion
In this study, MRI identified structural similarities between chronic ischemic myocardium compared to the non-ischemic myocardium. This finding supports myocardial tissue stability in the presence of stress induced ischemia.
Funding Acknowledgement
Type of funding source: Foundation. Main funding source(s): Zerbini Foundation and also by the FAPESP (2011/ 20876-2)
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