Study Evaluates IVUS for Detecting Dissections in Femoropopliteal Vessels After PTA

July 11, 2018—Nicolas W. Shammas, MD, et al published results from the iDissection classification study in Journal of Invasive Cardiology (2018;30:240–244).

Intact Vascular, Inc., the manufacturer of the Tack endovascular system for precision dissection repair after balloon angioplasty, issued a press release on the publication of the results. According to Intact, the background of the iDissection classification study is that dissections after percutaneous transluminal angioplasty (PTA) are often overlooked, underdiagnosed, and left untreated, which can affect both short- and long-term clinical outcomes. The use of intravascular ultrasound (IVUS) has been found to help visualize the presence and severity of dissections not typically seen on angiography.

In the iDissection study, 15 patients with femoropopliteal disease were treated with atherectomy and adjunctive PTA. Angiographic and IVUS images utilizing ChromaFlo imaging (Philips) were obtained at baseline, postatherectomy, and postangioplasty and were evaluated for the presence and severity of dissections.

Dissections seen on angiography were graded per the National Heart, Lung, and Blood Institute scale, and IVUS images were graded using the iDissection classification. All images were independently adjudicated by multiple core laboratories. Although angiography identified eight dissections, IVUS revealed 46 dissections—a ratio of 6:1 in favor of IVUS.

The iDissection study demonstrated that significant dissections may not be thoroughly observed with angiography, yet are substantially more visible when using IVUS, potentially altering the course of patient treatment in real time.

In the Intact's press release, Dr. Shammas commented, “Angiography is a suboptimal test to visualize the peripheral arteries. It underestimates vessel size, the presence and extent of calcium, thrombus, and stenosis, and does not give a clear picture of optimal stent expansion and apposition. Moreover, the iDissection data confirms that angiography seriously underestimates the presence and severity of dissections following endovascular intervention. The iDissection study validates the need for more sophisticated imaging, such as IVUS, to evaluate acute procedural results.” Dr. Shammas is Founder and Research Director of Midwest Cardiovascular Research Foundation in Davenport, Iowa.