IVUS vs. Angiography

Intravascular ultrasound (IVUS) is a valuable adjunct to angiography, providing new insights in the diagnosis of and therapy for coronary disease. Angiography depicts only a 2D silhouette of the lumen, whereas IVUS allows tomographic assessment of lumen area, plaque size, distribution, and composition. The safety of IVUS is well documented, and the assessment of luminal dimensions represents an important application of this modality.

In general IVUS is recommended for complex lesions: bifurcation lesions, long lesions, diabetics, left main and particularly restenosis lesions. But, there are very few cases where IVUS is not useful. The lesions one should  avoid doing IVUS in are situations where we have calcified tortuous anatomy, maybe hemodynamically unstable patients where it’s an emergency and you just need to get in there and get it fixed. Maybe a situation where we’re dealing with a small, very small artery, and there isn’t much doubt that the only size stent we are  going to be able to use is a 2.5mm drug-eluting stent and going in there and IVUS-ing a baseline is probably not going to change the mind.

 

Sometimes, we can see a somewhat sharp turn artery as a diseased vessel on angiogram which can be rule out by IVUS-ing. Once should not stenting the anxiety related reactions of chest pain with normal coronaries which only confirmed by a doubtful angiography.

IVUS  really helps us figure out where to land our stent. We’ve known for a long time that we want to land the distal end of our stent in as normal an artery segment as we can. Of course, the problem with angiography is we underestimate mild disease. So sometimes the vessel looks pretty good just beyond the lesion, but when we are  looking at that same region on ultrasound, many times we can see pretty severe disease in there.
In the future there will probably be this type of integrated IVUS-angiographic system called AIM, which stands for Angiographic IVUS Mapping, It is  believed by doctors , so you could look at the angiogram and see where your lesion is, put a cursor on there and the IVUS image would automatically link right to that spot.

In IVUS-guided versus non–IVUS-guided procedures, the incidence of stent thrombosis was reduced by 53% (0.55% vs 1.16%; P = .004), the incidence of MI was reduced by 38% (3.47% vs 5.59%; P < .0001), and the incidence of major adverse cardiovascular events (MACE, a composite of stent thrombosis, cardiac death, and MI) was reduced by 34% (4.9% vs 7.4%; P < .001).
IVUS guidance changed the procedure 74% of the time. IVUS use was associated with longer stent length and larger stent size without increasing periprocedural MI or the number of stents utilized. The majority of stents used in the study were of the latest generation and marketed globally. No additional safety issues were identified in the procedures in the study in which IVUS was used to place stents, noted the company.


References :
1-Michael C.Foster ,MD.FACC

2- Relationship Between Intravascular Ultrasound Guidance and ClinicalOutcomes After Drug-Eluting Stents: The ADAPT-DES StudyRunning title:Witzenbichler et al.; IVUS and DES Outcomes-Circulation , 2013