**3. Helpful tips to address difficulties performing basic steps of PCI**

## **3.1 Difficulty wiring**

Wiring the true lumen during PCI is the initial and most important step. Operators can face several difficulties and some solutions are listed:

1.Severe stenotic lesions:

Find the microchannel using multiple views and use escalating wire technique to provide more support to the wire tip.

Use a micro catheter or balloon to support wire's tip.


Adjust the wire tip to the most angulated vessel. Use angulatedmicro-catheter like super cross 45-90-120° or steerablemicro-catheter. Use dual lumen micro-catheter.

Use knuckled wire retro wiring technique: advancing knuckled wire in the main vessel beyond the takeoff of the branch angulated vessel then withdrawing

lesion preparation and intra-coronary Nitroglycerin, fluoroscopy based quantitative

*Cardiac Diseases - Novel Aspects of Cardiac Risk, Cardiorenal Pathology and Cardiac Interventions*

To assure good results, operator can use stent imaging enhancement technology (Available on Phillips Fluoroscopy system) and intravascular imaging. Most operators use post dilatation with balloon to achieve good angiographic results. This step has been shown to improve angiographic results. Clinically, the benefit and long-term outcome of this step is a complex question to answer as it has multiple variables and cofounders. It is related to the clinical presentation acute myocardial infarction vs. stable angina, type of lesion and stent generation. Best data support this step for bare metal stents and first-generation drug eluting stents. For second and third generation DES, the data are controversial [11–13]. Significant evidence supports this step [14]. However, some question it as it might lead to microvascular injury or distal embolization in the setting of acute myocardial infarction. It is best to make individual

Operator should minimize the number of stents used by using single stent and avoid stents overlap. This can be challenging in long lesions with significant discrepancy between proximal and distal vessel size or in challenging distal lesion in tortuous vessel. Using shorter and multiple stents might be required if other tech-

Stent restenosis is related to target vessel size (smaller have higher risk), stent length (longer higher risk), small diameter stents, undersized stent, stent drug type and body response (inflammation), ostial lesions, venous grafts lesions especially distal anastomosis to target vessel, presence of diabetes mellitus and calcifications. Appropriate oversizing might have beneficial results and reduce target lesion revascularization. Stents thrombosis risk increases with premature stopping of anti-platelets therapy, stents overlap, bifurcation lesions, stent edge dissection, stent's struts malapposition, time from implantation, poor distal flow post intervention, presence of diabetes mellitus and chronic kidney disease, reduced left ventricular systolic function. There are some data to subject larger vessel and especially RCA has more risk

**3. Helpful tips to address difficulties performing basic steps of PCI**

Wiring the true lumen during PCI is the initial and most important step.

Find the microchannel using multiple views and use escalating wire technique

2.Tortuous vessels and lesions: use wires with strong shaft support and torque

Use angulatedmicro-catheter like super cross 45-90-120° or steerablemicro-catheter.

Use knuckled wire retro wiring technique: advancing knuckled wire in the main vessel beyond the takeoff of the branch angulated vessel then withdrawing

Operators can face several difficulties and some solutions are listed:

Use a micro catheter or balloon to support wire's tip.

Adjust the wire tip to the most angulated vessel.

measurement and using intravascular imaging (IVUS or OCT).

decision to perform post dilatation in acute myocardial infarction cases.

niques for increasing support for delivery are not successful.

of thrombosis.

**3.1 Difficulty wiring**

transmission.

**230**

1.Severe stenotic lesions:

3.Angulated target vessels:

Use dual lumen micro-catheter.

to provide more support to the wire tip.

slowly toward till the tip of the wire engage the target vessel. This technique is helpful to wire a jailed branch vessel and assuring the wire is not between stent and vessel wall (under stent).
