Improvement of regional and global left ventricular function in magnetic resonance imaging after recanalization of true coronary chronic total occlusions.

BACKGROUND: Successful recanalization of true chronic total occlusion (CTO) has been linked to a decrease in cardiac mortality. We evaluated the effect of CTO recanalization on LVEF and regional wall motion using paired cardiac magnetic resonance imaging (cMRI) studies.

METHODS AND RESULTS: 43 patients underwent contrast enhanced cMRI prior to and 9 months after successful recanalization of a true CTO defined as thrombolysis in myocardial infarction flow 0 and duration of occlusion of more than 3 months. Regional wall motion was analyzed using the AHA model. For each segment the wall thickness (WT) was measured over the duration of one heart cycle and segmental wall thickening (SWT) was calculated. Left ventricular ejection fraction (LVEF) and volumes were measured. LVEF significantly increased by 2.4 ± 6.0% (p = 0.01). The increase was confined to patients with baseline LVEF below the median of 49.3% (4.1 ± 7.0%, p = 0.01) compared to 0.6 ± 4.0 (p = 0.48) in patients with baseline LVEF higher than the median. Segmental wall motion analysis was performed in 706 myocardial segments. SWT significantly increased in segments within the perfusion territory of the CTO vessel (5.1 ± 30.4%, p = 0.01), especially in dysfunctional segments at baseline with SWT(init) <45% (13.3 ± 24.3%, p < 0.001). In addition, SWT significantly increased in segments of non-CTO vessels (4.1 ± 32.1%, p < 0.01).

CONCLUSIONS: In conclusion, in patients with successful recanalization of CTO left ventricular ejection fraction and regional wall motion are significantly improved, especially in patients with decreased LVEF and in dysfunctional segments.