Complex patient subgroups that will be discussed in this chapter include:
Cardiogenic shock patients
CTO Manual Online case: 113
PCI Manual Online case: 62
Transcatheter aortic valve replacement (TAVR) is increasingly being performed for symptomatic aortic stenosis patients, even those at low surgical risk. Coronary angiography and percutaneous coronary intervention (PCI) is often required in TAVR patients and carries unique challenges, such as coronary artery engagement, especially in patients with self-expanding valves, which extend above the coronary ostia .
Given frequent difficulty in engaging the coronary arteries in TAVR patients, preprocedural CT angiography can be performed to help understand the three-dimensional geometric interaction among the valve prosthesis, the aortic root, and the coronary ostia to help predict and prepare for potential challenges of coronary reaccess ( Fig. 24.1 ) .
However, use of CT angiography in prior TAVR patients has several limitations :
CT cannot be performed in urgent or emergent situations, such as in patients with an acute coronary syndrome requiring urgent coronary angiography and PCI.
CT angiography requires contrast administration that increases the risk of contrast-induced acute kidney injury after additional contrast administration during cardiac catheterization.
Motion artifact and image quality may limit the ability to visualize leaflet orientation of the transcatheter valve relative to the coronary ostia, making it difficult to determine whether the commissural post may impede the ability to reaccess the coronary arteries.
Monitoring is performed as described in Chapter 2: Monitoring .
Medication administration is performed as described in Chapter 3: Medications .
Given frequent challenges associated with engagement in prior TAVR patients, femoral access may be preferred.
Coronary engagement should be performed with extreme care aiming for coaxial positioning, and avoiding deep coronary artery intubation .
Engagement depending on depth of valve implantation
If the Evolut-PRO CoreValve is positioned optimally (skirt below coronary ostia), it is feasible to engage the coronary artery in a coaxial manner, assuming the native aortic valve leaflets will not interfere with the path to the coronary ostium ( Fig. 24.2 , panel A).
If the valve is deployed high ( Fig. 24.2 , panel B) coronary obstruction would not occur due to the narrow waist of the valve and sufficient sinus of Valsalva width . However, selective coronary angiography would be difficult in this scenario and would have to occur from a diamond above the ostium, given that the supra-annular valve and its covered segment (e.g., sealing skirt) would be above the level of the ostium. A straighter catheter with a short tip, such as a Judkins right (JR) 4, could be used in this scenario, even for left main artery engagement .
Engagement depending on the position of the transcatheter valve commissures in relation to those of the native aortic valve
The circumferential sealing skirt of the Evolut-PRO CoreValve is 13 mm in height (14 mm in the 34-mm Evolut-R), however it rises up to 26 mm at the commissural insertion point ( Fig. 24.3 ). If a commissure ends up being positioned directly in front of the coronary ostium coaxial engagement of the coronary ostia would be challenging, if not impossible . Engagement also depends on the width of the sinus of Valsalva that determines the space between the valve frame and the coronary ostia; the wider the sinus the more room there is to manipulate a catheter toward the coronary ostia. A narrow sinus would require a very acute angle for the catheter to be pointing toward the ostia for a nonselective coronary angiogram. If selective engagement is required, a coronary wire would have to be manipulated into the coronary artery, and the guide, or a guide catheter extension, would then have to be railed into the ostium. This represents the most difficult scenario: a valve commissure overlying a low coronary ostium in a patient with a narrow sinus of Valsalva. The aforementioned description does not account for the native aortic leaflet height and severity of calcification facing the left and right sinuses. A tall and bulky leaflet may extend beyond the 13- or 14-mm sealing skirt of the repositionable Evolut-PRO self-expanding valve and would likely further add to the challenge of coronary reaccess .
Left coronary artery : Smaller catheters, such as a JL3.5 or JL3, are frequently used to engage the left main. On the contrary, engagement of the RCA can usually be managed with a JR4 catheter. There are reports of XB guide catheter kinking and entrapment through the valve diamonds ( Fig. 24.4 ) . The following measures may minimize the risk of catheter entrapment:
Crossing the stent frame perpendicularly through a diamond at the same level with the coronary ostium.
Using catheters with favorable geometry (e.g., left Judkins for left and right Amplatz for the right coronary artery).
Using a balloon and/or a guidewire to back the catheter out of the coronary ostium.