**4.2 Bifurcation lesion techniques**

Bifurcation of lesions in general is one of the most technically complex coronary interventions. Multiple classifications for bifurcation coronary lesions are available. The most common one is Medina classification which has three digits depending on true lesion involvement of vessels around bifurcation.

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

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

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

Using a GC with side holes. Again, side holes can cause a false sense of

Quick engagement and wiring followed by disengagement to minimize

Calcified ostial lesions that requires adjunct plaque modification such as atherectomy carries risk of causing aortic dissections. This can occur with simple angioplasty. The inflations time while performing angioplasty or stenting should be short as these vessels might be the only perfusion source of

inside the ascending aorta. A lot of operators recommend flaring the

protruding part with large balloon and high pressure to make the stent take the shape of the internal aorta. This step is important especially when future interventions are anticipated. Without this step, future engagement of the stent and PCI becomes a very difficult mission and almost impossible. There are special designed balloons that can help with achieving this step. A catheter with two balloons, two inflating ports, and three markers that identify the edges of the two balloons. Operators should use caution while using these double balloons as inflating proximal balloon inside the vessel can cause vessel injury. Sbazo technique is a unique technique where another wire is passed through the proximal stent cell and while advancing the stent the wire stops the advancement while assuring covering the ostium. The same technique can be used at a bifurcation ostium lesion while avoiding jailing the

Bifurcation of lesions in general is one of the most technically complex coronary interventions. Multiple classifications for bifurcation coronary lesions are available. The most common one is Medina classification which has three digits depending on

Missing the target: as operators try to match the proximal end of the stent to the ostium, it is not uncommon to miss the target ostial lesions. Locating the ostium is challenging and appropriate imaging views are critical here. To assure best view of ostial lesion, orthogonal views should be used. For ostial left main, superficial LAO/cranial and for RCA steep RAO and even lateral views are required depending on its origin. It is essential to know where the stent ends in regard to its radiopaque markers in order not to miss the ostium as some stents ends at the distant end of the radiopaque marker and others at the proximal end of the marker. In order to achieve good lesion coverage, stents are deployed to protrude couple of millimeters out of the coronary and

Phishing technique: it involves having the tip of the guide few millimeters close to the ostium without engagement then attempting to wire the coronary. If the ostium lumen can accommodate a micro catheter, then micro catheter can be used to approach the ostium with long wire to facilitate wiring the coronary. Steerable micro catheters are the most helpful when using this technique. Using a small 4 or 5Fr diagnostic catheter to engage and wire the coronary with a long wire then exchange with the appropriate guide catheter over the long

following techniques:

assurance.

ischemia.

wire.

the heart.

branch vessel.

**232**

**4.2 Bifurcation lesion techniques**

true lesion involvement of vessels around bifurcation.

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 the decision to choose one is related to several factors.

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 vessel and presence of trifurcation or proximal lesion.

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 balloons to avoid wire trapping complications.

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 level without compromise one of the bifurcation lumens.

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

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 ischemia by completely obstructing the coronary ostium.

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

the bifurcation. The second lumen can be used to wire the branch safely within the stent and provide support in challenging SB rewiring cases. However, this technique

When SB stenting is required, reverse crush, T-stenting, TAP or Culottes tech-

After wiring both the main vessel and its branch. A stent sized to the SB is placed into the branch vessel. To assure complete coverage of the lesion, part of the stent protrudes insides the MV. As the goal is to cover the whole bifurcation, the length of the protruding segment of stent correlates with the angulation angle. The smaller the angle the longer this protruding segment inside the MV. If the SB is taking off at 80° then theoretically, no part of stent should be protruding inside the MV. After SB stenting, a balloon loaded on the wire of the MV is used to crush the protruding segment of stent followed by stenting of the MV. The goal of mini crush that protruding segment of the stent would not jail the SB completely so if post stenting intra vascular imaging is performed, the distal part of the SB takeoff lumen will have two layers of stent, the protruding crushed segment of the SB stent and the MV stent while the proximal part will have only the MV stent. Rewiring the branch through the main stent struts and performing kissing balloon creating new carina is recommended. The lesion under the carina will have two layers of stents. If the segment of stent protruding inside the MV is long enough that when it is crushed by angioplasty/stenting the MV, the technique turns to crush stenting technique.

After wiring both vessels, loading a balloon on the MV wire, stenting the SB with significant part of stent protruding inside the MV is performed. The MV balloon then used to crush the protruding segment of the SB stent jailing the lumen of the branch completely with two layers of stents. Stenting of MV is then performed jailing the SB with additional layer of stent struts. Before that the SB wire is withdrawn to avoid wire trapping complications. Now, the SB is covered with three layers of stent struts which most likely will affect the flow of the SB. Thus, rewiring across these layers of stents is required and used to perform angioplasty to dilate the

It is similar to the crush technique but in reverse sequences. After wiring both vessels, the MV is stented then the SB is rewired across the MV stent struts which maybe challenging especially in the setting of true SB severe stenosis, and rewiring becomes more difficult with plaque shifting/angulation angle changes after stenting

completely inside the MV is deployed. At this point, depending on the angiographic

It is the most complicated technique but has a good supportive data. After wiring both vessels. The vessel with the hardest to rewire is stented first. Then alternating

the MV. A balloon angioplasty followed by stent that protrude partially or

results and the covering of diseased, the operator might crush the SB stent performing angioplasty inside the MV stent (followed by the rest of crush technique) or perform kissing balloon leaving segment of the protruding stent hanging

requires long wire (or extension wires) to make exchanges.

niques could be used.

*4.2.2 Mini crush technique*

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

*4.2.3 Crush stenting technique*

*4.2.4 Reverse crush technique*

in the lumen of the MV.

**235**

*4.2.5 Culottes' bifurcation stenting*

stent struts followed by performing kissing balloons.

disease which in turn increases the need for vessel revascularization due to more hemodynamically significant restenosis. The same percentage of stenosis could be tolerated better with less hemodynamic effect in larger non-diabetic vessels. If a patient is not a candidate for CABG, a hemodynamic support device should be considered depending on the severity of stenosis, calcification, the need for atherectomy or other lesion modification techniques, presence of aortic valve stenosis, and LV function. Even with normal LV function, operator should consider mechanical support with severe calcified lesions with high risk of acute vessel closure, low LVEF, prolonged ischemia or complication. Simultaneous kissing stents to minimize ischemia time is a good option especially in Medina 0.1.1 lesions. **Figure 4** shows a simple decision-making approach for bifurcation stenting.

#### *4.2.1 Provisional stenting*

Stenting from main vessel to main vessel or branch depends on size differences, angulation of the SB, and the easier vessel to rewire after jailing it in case further intervention is needed.

When the size difference is less between the SB and proximal MV compared to difference between distal lesion of MV and proximal vessel, then stenting from main vessel to the SB is a good option, otherwise, stenting from proximal to distal MV is most common especially in LAD bifurcation lesions. Stenting to SB like from proximal LCX to branch obtuse marginal is more common than stenting from proximal to distal LCX. Evaluating the SB flow is very important to make a decision whether it requires angioplasty or stenting. Before judging the branch flow, it is recommended to administer intracoronary nitroglycerin.

As long as SB has normal flow and is not at risk of closure, no further intervention is required. If SB flow is impaired, performing angioplasty of stent struts the next step. If the results of angioplasty weren't successful to improve the flow, or caused SB injury, stenting becomes required. For the same reason SB with normal flow or small lumen <2 mm should not be rewired unless poor flow is present as rewiring with or without angioplasty might cause more complications than benefits. When attempting to rewire the jailed SB through stent struts, there is always a concern of wiring under the stent or not able to wire the SB especially when POT is not performed. To avoid that, the MV wire can be used to rewire the SB as long as the operator does not withdraw the wire beyond the proximal edge of the stent. In this way, the operator can be assured that the wire is inside the stent. Another approach is to reverse wire the SB by wiring the MV stent with J tip wire and then the wire is withdrawn to the origin of SB. Lastly, a special twin pass micro-catheter loaded on the MV wire and passed till

**Figure 4.** *A simple decision-making approach for bifurcation stenting.*

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

the bifurcation. The second lumen can be used to wire the branch safely within the stent and provide support in challenging SB rewiring cases. However, this technique requires long wire (or extension wires) to make exchanges.

When SB stenting is required, reverse crush, T-stenting, TAP or Culottes techniques could be used.

## *4.2.2 Mini crush technique*

disease which in turn increases the need for vessel revascularization due to more hemodynamically significant restenosis. The same percentage of stenosis could be tolerated better with less hemodynamic effect in larger non-diabetic vessels. If a patient is not a candidate for CABG, a hemodynamic support device should be considered depending on the severity of stenosis, calcification, the need for atherectomy or other lesion modification techniques, presence of aortic valve stenosis, and LV function. Even with normal LV function, operator should consider mechanical support with severe calcified lesions with high risk of acute vessel closure, low LVEF, prolonged ischemia or complication. Simultaneous kissing stents to minimize ischemia time is a good option especially in Medina 0.1.1 lesions. **Figure 4** shows a simple decision-making approach for bifurcation stenting.

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

Stenting from main vessel to main vessel or branch depends on size differences, angulation of the SB, and the easier vessel to rewire after jailing it in case further

When the size difference is less between the SB and proximal MV compared to difference between distal lesion of MV and proximal vessel, then stenting from main vessel to the SB is a good option, otherwise, stenting from proximal to distal MV is most common especially in LAD bifurcation lesions. Stenting to SB like from proximal LCX to branch obtuse marginal is more common than stenting from proximal to distal LCX. Evaluating the SB flow is very important to make a decision whether it requires angioplasty or stenting. Before judging the branch flow, it is

As long as SB has normal flow and is not at risk of closure, no further intervention is required. If SB flow is impaired, performing angioplasty of stent struts the next step. If the results of angioplasty weren't successful to improve the flow, or caused SB injury, stenting becomes required. For the same reason SB with normal flow or small lumen <2 mm should not be rewired unless poor flow is present as rewiring with or without angioplasty might cause more complications than benefits. When attempting to rewire the jailed SB through stent struts, there is always a concern of wiring under the stent or not able to wire the SB especially when POT is not performed. To avoid that, the MV wire can be used to rewire the SB as long as the operator does not withdraw the wire beyond the proximal edge of the stent. In this way, the operator can be assured that the wire is inside the stent. Another approach is to reverse wire the SB by wiring the MV stent with J tip wire and then the wire is withdrawn to the origin of SB. Lastly, a special twin pass micro-catheter loaded on the MV wire and passed till

recommended to administer intracoronary nitroglycerin.

*4.2.1 Provisional stenting*

intervention is needed.

**Figure 4.**

**234**

*A simple decision-making approach for bifurcation stenting.*

After wiring both the main vessel and its branch. A stent sized to the SB is placed into the branch vessel. To assure complete coverage of the lesion, part of the stent protrudes insides the MV. As the goal is to cover the whole bifurcation, the length of the protruding segment of stent correlates with the angulation angle. The smaller the angle the longer this protruding segment inside the MV. If the SB is taking off at 80° then theoretically, no part of stent should be protruding inside the MV. After SB stenting, a balloon loaded on the wire of the MV is used to crush the protruding segment of stent followed by stenting of the MV. The goal of mini crush that protruding segment of the stent would not jail the SB completely so if post stenting intra vascular imaging is performed, the distal part of the SB takeoff lumen will have two layers of stent, the protruding crushed segment of the SB stent and the MV stent while the proximal part will have only the MV stent. Rewiring the branch through the main stent struts and performing kissing balloon creating new carina is recommended. The lesion under the carina will have two layers of stents. If the segment of stent protruding inside the MV is long enough that when it is crushed by angioplasty/stenting the MV, the technique turns to crush stenting technique.

### *4.2.3 Crush stenting technique*

After wiring both vessels, loading a balloon on the MV wire, stenting the SB with significant part of stent protruding inside the MV is performed. The MV balloon then used to crush the protruding segment of the SB stent jailing the lumen of the branch completely with two layers of stents. Stenting of MV is then performed jailing the SB with additional layer of stent struts. Before that the SB wire is withdrawn to avoid wire trapping complications. Now, the SB is covered with three layers of stent struts which most likely will affect the flow of the SB. Thus, rewiring across these layers of stents is required and used to perform angioplasty to dilate the stent struts followed by performing kissing balloons.

#### *4.2.4 Reverse crush technique*

It is similar to the crush technique but in reverse sequences. After wiring both vessels, the MV is stented then the SB is rewired across the MV stent struts which maybe challenging especially in the setting of true SB severe stenosis, and rewiring becomes more difficult with plaque shifting/angulation angle changes after stenting the MV. A balloon angioplasty followed by stent that protrude partially or completely inside the MV is deployed. At this point, depending on the angiographic results and the covering of diseased, the operator might crush the SB stent performing angioplasty inside the MV stent (followed by the rest of crush technique) or perform kissing balloon leaving segment of the protruding stent hanging in the lumen of the MV.

#### *4.2.5 Culottes' bifurcation stenting*

It is the most complicated technique but has a good supportive data. After wiring both vessels. The vessel with the hardest to rewire is stented first. Then alternating

applied after the MV stent has been deployed and kissing balloon inflation has been performed. In particular, TAP stenting was developed to ensure full SB ostium coverage by DES struts. To achieve this, the SB stent is delivered with intentional minimal protrusion inside the MV with an uninflated balloon positioned in the MV across the SB take-off. After SB stent deployment, kissing balloons inflation is immediately performed with the stent's balloon and the MV balloon. Further kissing balloon inflations with noncompliant balloons may be advisable in the case of suboptimal stent expansion. During the practice of TAP stenting, the operator should pay attention to and try to limit as much as possible the protrusion inside the MV which influences the length of the neo-carina. Nevertheless, similar to crush techniques, two main determinants of neo-carina length should be recognized: the SB take-off angle and the "quality" of pre-TAP kissing inflation. The impact of the SB take-off angle is quite intuitive: when the SB has a "T" shape take-off, small or absent SB stent protrusion inside the MV is needed to cover the SB ostium successfully. On the other hand, acute SB angles (Y-shapes) are associated with longer, oval-shaped SB ostia. Such an anatomic configuration implies the need for wider protrusion of the SB stent inside the MV, resulting in a longer neo-carina.

Engaging, performing angiogram and interventions on RIMA/LIMA carries higher risk for multiple reasons. LIMA is a vessel with high risk for dissection during any instrumentation. Most patients that requires LIMA interventions have significant underlying native vessel a baseline with possible occlusion of other bypass grafts. In a lot of clinical scenarios, LIMA could be the only source of

Grafts/LIMA interventions could be performed via any approach. Left radial or distal left radial has the advantage of avoiding complications of femoral approaches and avoid left subclavian issues. Most common LIMA interventions are related to anastomosis at the LAD, left subclavian pseud or true stenosis, and ostial lesions at the takeoff from left subclavian. Lesions in the body of LIMA are less common. When using femoral approach, a lot of operators prefer to use a short LIMA guide which allows for more wire to reach distally to distal LAD after the anastomosis. Short GC usually is not required when using left radial approaches and if needed,

Distal anastomosis interventions: in early post-operative days, grafts angiogram (especially arterial grafts LIMA, RIMA, radial) might appear concerning for a dissection or spasm and this could be related to the post-operative shock or vasoactive medication. Most of the times, graft has not yet matured, and later imaging would confirm that. Stenosis at the anastomosis is mostly related to operative technical issues during post-operative period vs. true progression of CAD during the months or years after. Intervention if truly indicated should be performed quickly but safely specially in fresh LIMA-LAD anastomosis. Operator should minimize occluding the target grafts with the guide catheter as much as safely possible. Direct stenting is a good option if a stent could be passed without ballooning. Fresh anastomosis and sutures might be frail and over inflation of the balloon or stent should be avoided. Stent is sized based on the size of the bypassed vessel. One of the challenges in SVG anastomosis interventions is sizing the stent. It is very common that SVG is much larger than the target bypassed vessel. Proximal optimization technique using balloon diameter sized to SVG to dilate the segment of stent inside SVG. Data suggests good outcome post PCI of LIMA-LAD if performed by experience operator. Proximal optimization technique to the size of the LIMA has a lower risk especially in

shortening the guide catheter is a technique that can be used.

**4.3 Grafts interventions**

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

perfusion for the heart.

early days post bypass.

**237**

wires positions to wire the SB through stent struts followed by performing angioplasty to dilate struts to the nonstented vessel. This step might require several balloons' angioplasty with escalating sizes. Then, stenting the SB jailing the first stented vessel. Again, here alternating wire positions are performed followed by final kissing balloon. The advantage of this technique is complete coverage of the lesions with stents. However, double coverage of proximal MV with two layers of stents and new carina have been controversial and suspected to increase risk of thrombosis. Most recent evidence suggests no difference between this technique and other two stents techniques in terms of stent thrombosis. Culottes' technique is best used when the branched vessels are close in diameter to the MV to avoid stent size mismatch and the angulation angle is acute below 70°.

#### *4.2.6 V stenting*

This technique is best used in bifurcation lesion Medina class 0.1.1 where the proximal MV is not involved or when the lesion is barely involving the proximal MV. After wiring both vessels, angioplasty of both vessels might be required regardless to pass stents followed by simultaneous kissing stenting. Stenting is step wise fashion with deploying one stent at time is feasible using 6F GC as long as it is followed by kissing balloons. Otherwise, performing kissing stent requires 7F GC.

#### *4.2.7 Double barrel kissing stents technique*

As in the case of V stenting, this technique requires 7F GC. It can be quick minimizing ischemia time and thus useful for large left main vessel with bifurcation disease involving LAD and LCX. After wiring both vessels, simultaneous stenting is performed creating double barrel in the proximal MV. Clearly, the stents in the proximal MV are not fully deployed and they are crushed against each other and the relationship between these barrels are not as simple it might appear. They are mostly twisted around each other and the size difference might affect the morphology of each stent within that part, i.e., one stent could be circle, the other is D shaped where in perfect scenario they both should have D shaped appearance with full apposition against the vessel. Clearly, re-accessing can be very challenging, which makes this technique less suitable for small vessel bifurcation lesions and for patients with expected need for further revascularization.

#### *4.2.8 T-stenting technique*

Bifurcation lesions that are appropriate for T stenting are lesions where the angulation angle is between 70 and 90°. The steps include wiring both vessels, performing necessary pre ballooning if needed, and then stenting the SB followed by stenting MV jailing the SB stent. A helpful technique to assure full coverage of bifurcation lesion is to leave inflated balloon inside the MV first then pulling he stent of the SB till it faces the resistance from the inflated MV balloon and then deflating that balloon followed by deploying the SB stent and finally stenting the MV. Depending on the results, rewiring through the MV stent struts might be necessary, followed by performing kissing balloons. When the angulation angle is less than 70, this approach is called TAP.

#### *4.2.9 T-stenting and small protrusion technique TAP*

It is a modification of the T-stenting technique aimed at optimizing "bail-out" SB stent implantation after MV treated by the "provisional" approach. Thus, it is

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

wires positions to wire the SB through stent struts followed by performing angioplasty to dilate struts to the nonstented vessel. This step might require several balloons' angioplasty with escalating sizes. Then, stenting the SB jailing the first stented vessel. Again, here alternating wire positions are performed followed by final kissing balloon. The advantage of this technique is complete coverage of the lesions with stents. However, double coverage of proximal MV with two layers of stents and new carina have been controversial and suspected to increase risk of thrombosis. Most recent evidence suggests no difference between this technique and other two stents techniques in terms of stent thrombosis. Culottes' technique is best used when the branched vessels are close in diameter to the MV to avoid stent

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

This technique is best used in bifurcation lesion Medina class 0.1.1 where the proximal MV is not involved or when the lesion is barely involving the proximal MV. After wiring both vessels, angioplasty of both vessels might be required regardless to pass stents followed by simultaneous kissing stenting. Stenting is step wise fashion with deploying one stent at time is feasible using 6F GC as long as it is followed by kissing balloons. Otherwise, performing kissing stent requires 7F GC.

As in the case of V stenting, this technique requires 7F GC. It can be quick minimizing ischemia time and thus useful for large left main vessel with bifurcation disease involving LAD and LCX. After wiring both vessels, simultaneous stenting is performed creating double barrel in the proximal MV. Clearly, the stents in the proximal MV are not fully deployed and they are crushed against each other and the relationship between these barrels are not as simple it might appear. They are mostly twisted around each other and the size difference might affect the morphology of each stent within that part, i.e., one stent could be circle, the other is D shaped where in perfect scenario they both should have D shaped appearance with full apposition against the vessel. Clearly, re-accessing can be very challenging, which makes this technique less suitable for small vessel bifurcation lesions and for

Bifurcation lesions that are appropriate for T stenting are lesions where the angulation angle is between 70 and 90°. The steps include wiring both vessels, performing necessary pre ballooning if needed, and then stenting the SB followed by stenting MV jailing the SB stent. A helpful technique to assure full coverage of bifurcation lesion is to leave inflated balloon inside the MV first then pulling he stent of the SB till it faces the resistance from the inflated MV balloon and then deflating that balloon followed by deploying the SB stent and finally stenting the MV. Depending on the results, rewiring through the MV stent struts might be necessary, followed by performing kissing balloons. When the angulation angle is

It is a modification of the T-stenting technique aimed at optimizing "bail-out" SB stent implantation after MV treated by the "provisional" approach. Thus, it is

size mismatch and the angulation angle is acute below 70°.

patients with expected need for further revascularization.

*4.2.7 Double barrel kissing stents technique*

*4.2.8 T-stenting technique*

**236**

less than 70, this approach is called TAP.

*4.2.9 T-stenting and small protrusion technique TAP*

*4.2.6 V stenting*

applied after the MV stent has been deployed and kissing balloon inflation has been performed. In particular, TAP stenting was developed to ensure full SB ostium coverage by DES struts. To achieve this, the SB stent is delivered with intentional minimal protrusion inside the MV with an uninflated balloon positioned in the MV across the SB take-off. After SB stent deployment, kissing balloons inflation is immediately performed with the stent's balloon and the MV balloon. Further kissing balloon inflations with noncompliant balloons may be advisable in the case of suboptimal stent expansion. During the practice of TAP stenting, the operator should pay attention to and try to limit as much as possible the protrusion inside the MV which influences the length of the neo-carina. Nevertheless, similar to crush techniques, two main determinants of neo-carina length should be recognized: the SB take-off angle and the "quality" of pre-TAP kissing inflation. The impact of the SB take-off angle is quite intuitive: when the SB has a "T" shape take-off, small or absent SB stent protrusion inside the MV is needed to cover the SB ostium successfully. On the other hand, acute SB angles (Y-shapes) are associated with longer, oval-shaped SB ostia. Such an anatomic configuration implies the need for wider protrusion of the SB stent inside the MV, resulting in a longer neo-carina.

### **4.3 Grafts interventions**

Engaging, performing angiogram and interventions on RIMA/LIMA carries higher risk for multiple reasons. LIMA is a vessel with high risk for dissection during any instrumentation. Most patients that requires LIMA interventions have significant underlying native vessel a baseline with possible occlusion of other bypass grafts. In a lot of clinical scenarios, LIMA could be the only source of perfusion for the heart.

Grafts/LIMA interventions could be performed via any approach. Left radial or distal left radial has the advantage of avoiding complications of femoral approaches and avoid left subclavian issues. Most common LIMA interventions are related to anastomosis at the LAD, left subclavian pseud or true stenosis, and ostial lesions at the takeoff from left subclavian. Lesions in the body of LIMA are less common. When using femoral approach, a lot of operators prefer to use a short LIMA guide which allows for more wire to reach distally to distal LAD after the anastomosis. Short GC usually is not required when using left radial approaches and if needed, shortening the guide catheter is a technique that can be used.

Distal anastomosis interventions: in early post-operative days, grafts angiogram (especially arterial grafts LIMA, RIMA, radial) might appear concerning for a dissection or spasm and this could be related to the post-operative shock or vasoactive medication. Most of the times, graft has not yet matured, and later imaging would confirm that. Stenosis at the anastomosis is mostly related to operative technical issues during post-operative period vs. true progression of CAD during the months or years after. Intervention if truly indicated should be performed quickly but safely specially in fresh LIMA-LAD anastomosis. Operator should minimize occluding the target grafts with the guide catheter as much as safely possible. Direct stenting is a good option if a stent could be passed without ballooning. Fresh anastomosis and sutures might be frail and over inflation of the balloon or stent should be avoided. Stent is sized based on the size of the bypassed vessel. One of the challenges in SVG anastomosis interventions is sizing the stent. It is very common that SVG is much larger than the target bypassed vessel. Proximal optimization technique using balloon diameter sized to SVG to dilate the segment of stent inside SVG. Data suggests good outcome post PCI of LIMA-LAD if performed by experience operator. Proximal optimization technique to the size of the LIMA has a lower risk especially in early days post bypass.

second layer of stent depends on the results of angioplasty, size of the vessel, and long-term outcome. If the mechanism of restenosis is under expanded stent, fibrotic tissue, calcifications underneath the stent or hyper intimal hyperplasia, the treatment is targeting the underlying tissue. Available treatment options are those used for adjunct plaque modifications (brachytherapy, LASER, and intravascular lithotripsy).

Supra-annular valves like CoreValve bio prosthetic makes coronary access challenging. The goal is to a use a guide catheter to cross the cells of the bio prosthetic valve at the level of the coronary. Best approach is to use a 0.5 shorter guide catheter than usually used. Wire assisted technique to manipulate the GC to sit within the bio prosthetic and at the appropriate cell level to cross toward the coronary ostium. Manipulating the GC with a 0.035″ guide wire should be performed within the lumen of the aorta and away from the aortic wall to avoid aortic or coronary ostium injury. Guide wire makes the GC stiff and moving the GC quickly could cause the GC to jump quickly and damage the coronary ostium. Once the GC is in a good trajectory and directed toward the coronary ostium, GC should be advanced slowly

Percutaneous coronary interventions have always been crucial in medical care. Now more than ever, with rapidly evolving percutaneous interventions and less surgical interventions, coronary percutaneous interventions are priority. Developing required technical skills and mastering basic and complicated intervention techniques have never been as important as they are now. Before proceeding with any intervention, all necessary equipment and medications should be available. Other essential requirements for any successful intervention include planning, having competency in required techniques, early recognition, and being prepared to

Medicine (Interventional Cardiology), VA Medical Center, Indiana University

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

**4.5 Post aortic valve replacement coronary intervention**

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

toward the ostium.

manage complications.

**Conflict of interest**

**Author details**

Imran Khalil

**239**

The author declares no conflict of interest.

School of Medicine, Indianapolis, Indiana

provided the original work is properly cited.

\*Address all correspondence to: elimrans@hotmail.com

**5. Conclusion**

SVG are prone to thrombosis. Microvascular thrombosis can lead to bad outcomes. Using distal embolic protection (**Table 15**) in cardiac vessels interventions has showed benefits in interventions on SVGs especially with thrombotic lesions. The goal of distal embolic protection is to minimize/stop any thrombi from traveling distally to microvasculature. These devices cannot be used for all SVGs interventions. Distally to the target lesion, vessel should have about 4 cm safe landing segment where the device can be deployed. Severe stenotic lesions (especially aortoostial lesions) make using distal embolic protection technically challenging or impossible. Some operators advocate in such cases with difficulty passing the embolic protection device is to perform direct stenting if it allows. Fibrotic lesions (instent restenosis) with no friable thrombotic material, might not benefit from embolic protection. Direct stenting is another approach to minimize distal embolization and microvascular obstruction when feasible. Aneurysmal changes in SVG are very common which makes stent sizes difficult. Sizing should be based on the nonaneurysmal segment and post dilation can be used when needed. Proximal embolic protection devices are still available but are not used as much as the distal one during PCI on SVGs. The idea of these devices to reduce the thrombi that can travel upwards and cause organ ischemia specifically a stroke.

No reflow phenomena is common during any coronary or graft intervention. It is more common with thrombotic lesions and thought to be related to microvascular thrombosis and/or dysfunction. In addition to minimize clot burden with embolectomy, angioplasty and stenting to trap clots, administrating of microvascular active medications nitroprusside, verapamil and/or adenosine is necessary.

#### **4.4 Instent restenosis treatment**

Simple focal restenosis is usually treated with DES. The era of DES changed the approach of instent restenosis treatment. A second and a third layer of stents can be used to treat the lesion especially focal lesions in the body of the stent or edge of stent whether the prior used stent was a BMS or DES. Treatment of instent restenosis can be very challenging due to the variable potential underlying pathophysiology of stent restenosis: undersized, under expanded stent, presence of calcification, neoatherosclerosis, fibrotic tissue or presence of diffuse instent restenosis. Understanding the mechanism of restenosis is the main step to choose the appropriate treatment strategy. Intravascular imaging with IVUS or OCT if possible can be very helpful. However, most of the time these imaging catheters cannot cross the restenosis. In these setting, ballooning might be the only option.

In case of diffuse instent neoatherosclerosis cutting balloons is not a good option especially if the prior stents are well sized and fully apposed. The decision of adding a


#### **Table 15.** *Distal embolization protection devices.*

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

second layer of stent depends on the results of angioplasty, size of the vessel, and long-term outcome. If the mechanism of restenosis is under expanded stent, fibrotic tissue, calcifications underneath the stent or hyper intimal hyperplasia, the treatment is targeting the underlying tissue. Available treatment options are those used for adjunct plaque modifications (brachytherapy, LASER, and intravascular lithotripsy).
