By: Faisal Latif, MD, FSCAI and Suresh Mulukutla, MD, FSCAI

Transcatheter aortic valve replacement (TAVR) is increasingly performed in patients who are at high surgical risk for surgical aortic valve replacement. The frequency of coronary artery disease is as high as 70% in patients with severe aortic stenosis¹. It is routine practice to perform pre-operative coronary angiography and PCI in patients for whom TAVR is planned. However, many patients require post-TAVR coronary angiography and intervention. Depending on the type of the percutaneous valve, this may not be as easy as it is in the absence of a percutaneous valve. In this tip-of-the-month, we discuss nuances and tips & tricks which can be employed for coronary angiography in these patients.  

Issues related to coronary angiography in post TAVR patients

A variety of percutaneous valves are available for commercial use. Many factors affect the final position of the outflow portion of the transcatheter heart valve, with respect to the coronary takeoff, including valve height, implant depth and coronary distance from the annulus. Further, the type of valve also has an important impact on the ability to selectively engage the coronary ostia. Coronary angiography is usually not difficult in patients with optimally positioned sub-coronary percutaneous valves, such as the Sapien. On the other hand, selective coronary angiography can be very challenging or even impossible following implantation of partially supra-coronary valves, such as the CoreValve. Catheters can get caught up in the crown of the stent frame of such valves or may be unable to get past the stent struts to selectively engage the coronary arteries. Higher than optimal placement of the valve and placement of a valve within another percutaneous valve (to treat aortic insufficiency after placement of the first valve) can make selective coronary engagement impossible.  

Diagnostic coronary angiography in post TAVR patients

In a case series of 1000 patients, 35 patients required coronary angiography post TAVR. Coronary angiography was successful with standard trans-femoral diagnostic catheters in all cases with a sub-coronary valve, mainly the Sapien XT². However, selective angiography was possible in only 3 out of 15 patients with a valve that covered the coronary ostia (mainly CoreValve). Table 1 below summarizes the types of valves in this study and the catheters for coronary angiography suggested by the authors. 

Table 1—Types and properties of commonly used trans-catheter valves along with recommendations for catheters for diagnostic coronary angiography². LCA = Left Coronary Artery; RCA = Right Coronary Artery

A 0.035-inch J wire protruding from the tip of the diagnostic catheter should prevent the catheter tip from catching on the crowns located at the top of the stent frame in a supra-coronary valve.

PCI in post TAVR patients

PCI in patients with sub-coronary valves can usually be performed with standard PCI guiding catheters unless the valve has been placed too high. Special care should be taken with guide catheter engagement and withdrawal in patients with supra-coronary valves. Entrapment of an extra-back up guide catheter after PCI, in the frame of a CoreValve Evolut, was reported which resulted in fatal left main dissection. The authors have published instructive images and videos which demonstrate the possible reason for entrapment and a more optimal method of engaging the left main³. In some cases, non-selective engagement with a guide catheter can allow advancement of one or more supportive guide wires to stabilize the guide and allow PCI. The use of micro-catheters and guide extension can be considered. A left radial approach may allow better negotiation within the aortic stent and valve leaflets compared with a right radial approach⁴. Based on individual case reports, useful guide catheters for include IM and JL4 guides for the left main and AR1 and JR 3.5 guides for the RCA⁵.

Best practices for post-TAVR PCI posted by the makers of the Evolut TAVR platform include the following-

1. Perform aortography to identify the coronary take-off.
2. Cannulate the coronary ostia through the middle of the valve frame cell at the level of the coronary takeoff. If there is difficulty with the frame cell directly coaxial to the ostium, use another cell. Avoid cannulation of the ostia from below the coronary takeoff.
3. Always remove the guide catheter over a wire.
4. Disengage the guide catheter from ostium, then withdraw through the frame cell. If there is difficulty removing the guide catheter from the ostium, use a balloon to disengage prior to pulling.
5. Counting alternating diamonds from below, the top of the sealing skirt is at 2.5 diamonds, and the top of the commissure point is at 5 diamonds.

The experience of Left Main (LM)-PCI during of following TAVR has been reported⁶. There is no difference in one-year mortality in patients undergoing planned TAVR plus LM-PCI compared with those undergoing TAVR alone (p = 0.83) and was not different between protected and unprotected LM-PCI. However, patients undergoing LM-PCI because of a complication of TAVR carry a higher mortality at 30 days (15.8% vs. 3.4%; p = 0.013). In this study, nine patients required LM-PCI at a median time interval of approximately 1-year post-TAVR. There were no reported issues with engaging the LM ostium in any of the nine patients, including four patients who had a CoreValve. 

Conclusions

The utilization of TAVR is expanding rapidly with trials ongoing in low-risk patients as well. Access to coronary arteries will become increasingly important due to longer life expectancy in patients at low and intermediate surgical risk. Coronary angiography and PCI is typically not an issue following sub-coronary valves like the Sapien. However, engagement of coronary ostia after implantation of supra-coronary valves, such as the CoreValve, can be challenging. There have been some concerns about the appropriateness of placing supra-coronary valves in younger patients who may require multiple coronary angiographic and PCI procedures over their lifetime. Further refinements and innovation in the design of catheters (both diagnostic and interventional) for these patients is needed. In the meantime, a careful understanding of valve structure and its relation to the coronary ostia, along with great caution in catheter advancement and withdrawal in the case of supra-coronary valves, is required. Reaching out to an experienced TAVR operator in the case of difficulties or even before an anticipated case can be very valuable.     

 References:

1. Hamm CW, Möllmann H, Holzhey D, et al. The German Aortic Valve Registry (GARY): in-hospital outcome. Eur Heart J. 2014;35(24):1588-98.
2. Blumenstein J, Kim WK, Liebetrau C, et al. Challenges of coronary angiography and intervention in patients previously treated by TAVI. Clin Res Cardiol. 2015 Aug;104(8):632-9.
3. Harhash A, Ansari J, Mandel L, et al. STEMI after TAVR: procedural challenge and catastrophic outcome. JACC Cardiovasc Interv. 2016; 9(13): 1412-3.
4. Greenberg G, Kornowski R. Coronary angioplasty after self-expandable transcatheter aortic valve implantation. J Invasive Cardiol. 2013; 25(7):361-3.
5. Khan A, Gilani S, Dharmashankar K, et al. Percutaneous coronary intervention after transcatheter aortic valve replacement; approach and challenges. J Am Coll Cardiol 2016;68(4):432-33.
6. Chakravarty T, Sharma R, Abramowitz Y, et al. Outcomes in Patients With Transcatheter Aortic Valve Replacement and Left Main Stenting: The TAVR-LM Registry. J Am Coll Cardiol 2016;67(8):951-60.