Vinay Malhotra, MD, a cardiologist at the Cardiac Study Center in Tacoma, Wash., evaluated in-stent restenosis (ISR) and chronic total occlusions (CTO) in the lecture series “The Latest Advances in Cardiovascular CT” on Saturday at Transcatheter Cardiovascular Therapeutics (TCT) conference in Washington, D.C.
Malhotra reported that 615,000 stents were implemented in the United States in 2005. Stent length and diameter varied in bare metal stents (BMS) and drug-eluting stents (DES). The median of BMS length was 16.4mm and 15.5mm in DES, while the median diameter was 3.3 in BMS and 3.0 in DES. Data from 16-slice CT was not as effective, according to Malhorta. He said that the positive predictive value varies, but there is a low prevalence of restenosis.
For stent visualization, Malhorta said you need to pay particular attention to quality data set. He also stressed the need to look for edge stenosis: “Don’t just look at stent, but look at the branches as well.”
Malhorta suggested that his fellow cardiologists invert the window level, which is his personal method. He also advised his colleagues to avoid motion artifacts and “make sure there is visualization and contrast; if not it usually indicates restenosis.”
Visualization of lumen within coronary artery stent by multidetector CT is improved, according to Malhorta. With CTO, the stent length is relevant. He said when the lumen interruption in stents was greater than 8mm, there was total occlusion, and in stents less than 8mm, there was subtotal occlusion. Malhorta stated that it is also 70 percent sensitive for occlusions.
Length of lesions is the main discriminator between the two approaches, Malhorta concluded.