Among patients with CAD referred for delayed-enhancement CV magnetic resonance who had regional myocardial wall thinning, limited scar burden was associated with improved contraction of the heart and reversal of myocardial wall thinning after revascularization.
This finding suggests that myocardial thinning is potentially reversible,” Dipan J. Shah, MD, from Duke Cardiovascular Magnetic Resonance Center, Duke University Medical Center, and colleagues reported.
Dipan J. Shah
Researchers evaluated 1,055 patients with known CAD undergoing delayed-enhancement CV magnetic resonance (CMR) imaging from August 2000 through January 2008.
Of the patients screened, 19%had regional wall thinning, which was defined as end-diastolic wall thickness ≤5.5 mm). According to the abstract, wall thinning affected a mean 34% of left ventricular surface area. In these regions, the mean extent of scarring was 72%, and 18% of thinned regions had limited scar burden (defined as ≤50% of total extent).
The researchers also studied 42 patients with regional wall thinning undergoing revascularization and follow-up cine-CMR. In this group, there was an inverse relationship between scar extent in the thinned region and regional and global contractile improvement (P<.001 for both). In thinned regions with limited scar burden, end-diastolic wall thickness after revascularization increased from 4.4 mm to 7.5 mm (P<.001), according to the abstract.
According to multivariable analysis, scar extent was strongly associated with contractile improvement (slope coefficient, –0.03; 95% CI, –0.04 to –0.02) and reversal of thinning (slope coefficient, –0.05; 95% CI, –0.06 to –0.04).
“We believe our study provides new insights into the pathophysiology of thinned myocardium and more broadly the process of reversible ischemic injury,” Shah and colleagues wrote. “The data show that thinned myocardium may consist of limited scar tissue and can recover function — concepts that are both inconsistent with current views.”
Disclosure:Shah reports serving as a consultant to Astellas Pharmaceuticals; receiving grants pending from Astellas Pharmaceuticals, Methodist Hospital Research Institute and Siemens Medical Solutions; and receiving payment for lectures from AstraZeneca, Lantheus Medical Imaging and Takeda. See the full study for a list of the other researchers’ disclosures.