Читать книгу Interventional Cardiology - Группа авторов - Страница 263

Coronary stents are challenging to evaluate on CTA because of partial voluming artifact that causes apparent enlargement of the stent and obscures the lumen (Figure 10.1c). This is exaggerated with smaller stents and overlapping or bifurcation stents.

To evaluate for in‐stent restenosis (ISR), the in‐stent lumen must be directly visualized (Figure 10.1b). Contrast enhancement distal to the stent could be secondary to retrograde filling by collaterals. Improvement in CTA technology has led to an improvement in evaluation of ISR. A recent meta‐analysis evaluated 35 studies with data from 2656 patients that used CTA to diagnose ISR. Not only did CTA have a high sensitivity and specificity for detection of ISR but also by demonstrating a high positive and low negative Likelihood Ratio, the authors concluded that CTA was an excellent test to rule in and rule out ISR, and serve as a good screening test. CTA was more sensitive for stents with a diameter of >3mm, more accurate for stents with thickness <100microns and less accurate at higher heart rates [28].

CTA has been shown to be reliable in excluding ISR in stents implanted in the left main (LM) and proximal left anterior descending/circumflex (LAD/Cx), as these stents have larger lumens [29]. This is important because routine angiographic surveillance 6 months after PCI for LM STEMI is recommended [30] and CTA is considered appropriate for this purpose [31].