**4. Special challenging cases of PCIs**

## **4.1 Aorto-ostial lesions**

Aorto-ostial lesions (RCA, left main, and bypass grafts) can be challenging for several reasons:

Engaging challenges: after selecting appropriate guide shape, engaging severe lesions most likely would cause dampening, possibly ischemia, dangerous arrhythmias, and subsequent hemodynamic effect. To avoid these issues or in cases with challenging coronary take offs, operators can use one or more of the following techniques:

In order to make bifurcation stenting simpler, the first decision is to decide whether the single-stent (provisional stenting) or the two-stent approach is the appropriate technique. There are significant data comparing provisional stenting to other two stent techniques. Both are acceptable techniques with good outcome and

Several techniques are used for bifurcation lesions. Deciding the best technique to use depends on multiple factors: medina classification, the angle between main and branch vessels, size difference of main and branch vessels, difficulty to rewire the sent struts, expected plaques shifting/angle changes post stenting and need for branch stenting distal to the bifurcation lesion, size and territory size of branch

Proximal optimization technique POT is an important step while performing any PCI and especially in the setting of bifurcation stenting. It refers to performing angioplasty inside the proximal segment of the stent/stents (making sure the distal end of the balloon at the level of side branch) to make sure proximal stent are well apposed and dilated to match the proximal vessel size. Injecting contrast while the balloon is inflated can help assuring well stent apposition when no contrast leak to distal vessel. POT allows safe rewiring and further intervention of the SB when required. It is important to perform POT at the right level, repeat it or perform kissing balloons if the SB was ballooned to optimize any possible distortion of the stent and to remove the SB wire before repeating POT or performing kissing

Final kissing balloon is recommended in all two stents techniques. Kissing balloons goal is to optimize the bifurcation carina and lumens of both vessel at this

IVUS-assisted bifurcation stenting has better outcome especially in distal left

For any bifurcation lesion, protecting both vessels, branch vessel (side branch SB) and main vessel (MV) by wiring them is recommended especially when branch vessel is 2 mm and larger in diameter. Even in Medina 0.1.0 lesions, wiring both vessel for protection is recommended. Acute vessel closure of large branch could occur when least expected especially in the setting of small bifurcation angle. It is very important to pre-determine the best views that allow the operator to evaluate the bifurcations accurately and assess the changes in both branches and main vessel at the same time with each step. Orthogonal views are important during all steps. There is no available guide catheter that allows simultaneous three balloon inflations or stent deployments. There are techniques that use two guide catheters one 7Fr and the other 6 or Fr to treat trifurcation lesion with the risk of inducing

Bifurcation lesions that carry the highest risk are true bifurcation lesions Medina

1.1.1 of distal left main involving ostial LAD and LCX. Unprotected left main is referred to any left main with no bypass to the LAD or LCX. It is important to recognize that intervention on unprotected left main carries a higher risk especially in the setting of left dominant system. Although recent emerging data suggest a similar outcome comparing PCI to CABG in such lesions even in diabetic patients, CABG still has the best data [11–13]. Discussion of the data is beyond this chapter. However, a simple decision-making approach is that the more complex anatomy, the more benefit CABG can provide especially in diabetic patients with low left ventricular ejection fractions [14]. It is important to recognize that diabetic patients have higher risk of restenosis and tend to have smaller vessels' lumen due to diffuse

main bifurcation lesion. Because fluoroscopy angiogram provides only twodimensional images, intravascular imaging with IVUS and/or OCT can be very helpful to understand the morphology of bifurcation stenosis if performed before

and after to evaluate the results and need for further intervention.

the decision to choose one is related to several factors.

*Coronary Artery Intervention Techniques DOI: http://dx.doi.org/10.5772/intechopen.93458*

vessel and presence of trifurcation or proximal lesion.

balloons to avoid wire trapping complications.

level without compromise one of the bifurcation lumens.

ischemia by completely obstructing the coronary ostium.

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