*2.3.2 Sizing of guide catheter*

There are four available sizes for coronary interventions (**Table 8**). Amount of contrast used in PCI increases with increasing guide catheter size.5Fr guide catheters: rarely used. Allows for simple single vessel PCI.


#### **Table 8.**

*Different guide catheter designs per company and sizes.*

6Fr guide catheters:

coronary with 0.014 guide wire and secure guide engagement. This technique is mostly used for radial approach especially in patients with extensive

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

Consider longer sheath to provide good support through tortuous vessels. This

If more support is needed and guide catheter needed to be advanced inside the

Guide catheters are available with or without side holes. Side holes purpose to prevent coronary obstruction by allowing some blood flow especially when using severe ostial lesions. Some operators argue that although using side holes can help avoid dampening of pressure, it does not support much coronary support and only give operators a false sense of comfort. Interventional guide wires can come out of these side holes and make it to coronary and unless operators are aware of that potential issue, complications can occur. Lastly, side holes can increase contrast volume used and weaken the tip of the guide

Advancing any instrument can push the guide out (especially if not a good support guide) causing disengagement and vice versa; pulling instruments can create a suction mechanism and advance the guide catheter deep inside the coronary and cause complications (dissection, perforation, and ischemia). Operators can use this mechanism to their benefit to provide more support or

coronary, operator should perform that over a wire or a balloon.

disengage the guide when needed (i.e. stenting ostial left main).

In addition to tip shape and length, shaft length is another important characteristic. Shorter guide catheters are used in CTO, bypass grafts and internal mammillary artery IMA interventions to allow for more wire to reach lesions in retrograde CTO approach and distal lesion in the grafts, anastomosis or target bypassed vessel. Longer shafts are used in tall patients or patients with significant tortuous aorto-femoral vessels. Standard shaft length is 100 cm, short is 80 or 90 cm, and long is 110–115 cm. Operators can shorten the guide by

cutting a segment of the guide and connect them using sheath segment.

There are four available sizes for coronary interventions (**Table 8**). Amount of

**Outer lumen size (French) 5 6 7 8**

Boston Scientific/Wiseguide NA 0.066 0.076 0.086 Abbott/Viking NA 0.068 0.078 0.091 Boston Scientific/Mach1 NA 0.070 0.081 0.091 Cordis/Vista Brite Tip 0.056 0.070 0.078 0.088 Medtronic/Launcher NA 0.071 0.081 0.090

contrast used in PCI increases with increasing guide catheter size.5Fr guide catheters: rarely used. Allows for simple single vessel PCI.

**Manufacturer/guide design Inner lumen size (inch)**

Bleed back from the hemostasis valve after performing exchanges to avoid introducing air or building clots in the system. This is very important while performing complex interventions with multiple wires and balloons and after

tortuous vessels.

is mainly a femoral approach option.

catheter and make it prone to kink.

*2.3.2 Sizing of guide catheter*

*Different guide catheter designs per company and sizes.*

**Table 8.**

**214**

aspiration thrombectomy.

The workhorse size for most of PCI cases.

Allow for performing kissing rapid exchange balloons of almost any coronary size.

Does not allow simultaneous double stenting techniques.

Allow for simultaneous balloon and stent deployments but with limitation of size related to stent size.

Allow for rotational atherectomy max size Rotablator 1.5.

Limited on the size of covered stent that can be used. For Graftmaster covered stent (Max size 3.5 mm stent). Newer PK papyrus covered stent can fit in 5Fr for sizes up t0 4.0 mm and requires 6Fr guide for >4.0 mm stents.

7Fr guide catheters:

The most commonly used size in high risk interventions for technical support or in preparation to deal with complications:

Allow for simultaneous double stenting techniques.

Allow for rotational atherectomy max size Rotablator 1.75. Allows for two over the wire balloons.

8Fr guide catheter:

Limited in availability.

Used for high risk interventions and CTO.

Allow for rotational atherectomy max size Rotablator 2.0.

Required for complex CTO intervention where intravascular ultrasound (IVUS) directed true lumen reentry and balloon are required.
