Myocardial fibrosis amount predictive of long-term survival after aortic valve replacement
Azevedo CF. J Am Coll Cardiol. 2010;56:278–287.
Kramer CM. J Am Coll Cardiol. 2010;56:288–289.
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Quantitative assessment of myocardial fibrosis was associated with the degree of left ventricular functional improvement, as well as all-cause mortality, study results suggested.
Researchers from the Heart Institute, University of Sao Paulo Medical School, Brazil, examined 54 patients scheduled to undergo aortic valve replacement via contrast-enhanced MRI between 2001 and 2003. They used delayed enhancement for quantitative assessment of myocardial fibrosis and quantified interstitial myocardial fibrosis by histological analysis of myocardial samples gathered during CABG.
There was a positive correlation between the amount of myocardial fibrosis measured by histopathology and by contrast-enhanced MRI (r=0.69, P<.001), whereas the amount of myocardial fibrosis had an inverse relationship with the degree of LV functional improvement after surgery (histopathology: r=–0.42, P=.04; contrast-enhanced MRI: r=–0.47, P=.02). Kaplan-Meier analyses indicated that higher degrees of myocardial fibrosis accumulation were linked with worse long-term survival. Independent predictors of all-cause mortality — as determined by multivariate Cox regression analyses — were patient age and the amount of myocardial fibrosis.
“This is the first study to demonstrate that the amount of myocardial fibrosis, either by histopathology or by contrast-enhanced MRI, is also a predictor of long-term survival after aortic valve replacement,” the researchers wrote. “In the future, this marker of chronic myocardial injury, which can be noninvasively quantified by contrast-enhanced MRI, might have the potential to be useful in the difficult decision-making process regarding the best moment to indicate a valve replacement surgery in patients with severe aortic valve disease.”
In an editorial accompanying the study, Christopher M. Kramer, MD, with the departments of medicine and radiology and the CV imaging center at the University of Virginia Health System in Charlottesville, said this study is an important demonstration of the role of myocardial fibrosis in aortic valve disease.
“As the list of conditions associated with fibrosis that can be imaged by cardiac magnetic resonance grows, the imaging community must look toward ways of fine-tuning the imaging to delineate microscopic fibrosis,” Kramer wrote. “Once that is finalized, turning the identification of fibrosis into therapeutic advances is an essential next step.”
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Comparable effectiveness observed between platinum chromium and stainless steel stents
Kereiakes D. J Am Coll Cardiol. 2010;56:264-271.
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A platinum chromium alloy stent proved to be equally efficacious and safe when compared with a stainless steel stent, according to results from the PERSEUS WH randomized controlled study.
“The PERSEUS WH trial provides the necessary assurance of safety and relative efficacy of the novel platinum chromium Taxus Element paclitaxel-eluting stent (Boston Scientific) platform, demonstrating noninferiority to the Taxus Express paclitaxel-eluting stent (Boston Scientific) with respect to the incidence of target lesion failure at 12 months and the severity of residual angiographic stenosis at 9 months,” the researchers reported.
They attained these results through the intent-to-treat analysis of 1,262 patients who were either treated with a stainless steel stent (Express; n=320) or a platinum chromium stent (Element; n=942). Patients had de novo coronary atherosclerotic lesions with a length ≤28 mm in reference vessels ≥2.75 m to ≤4 mm in diameter. The primary endpoint was the 12-month rate of target lesion failure, whereas the secondary endpoint was the 9-month angiographic in-segment percentage diameter stenosis.
The platinum chromium stent was noninferior to the stainless steel stent in regards to the incidence of target lesion failure (platinum chromium, 5.57% vs. stainless steel, 6.14%) and diameter stenosis (platinum chromium, 3.09% vs. stainless steel, 3.12%). Researchers also reported no differences in clinical outcomes at 12 months between stent groups, as well as infrequent stent thrombosis (stainless steel, 0.3% vs. platinum chromium, 0.4%).
“No safety concerns regarding either the novel metal alloy or modified stent design were observed,” the researchers said. “The PERSEUS WH trial demonstrates successful transfer of paclitaxel-eluting stent technology from stainless steel to a platinum chromium alloy platform.”
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