Imaging in Valve Procedures for an Optimal Patient Outcome
Can you tell us about your position and the structural heart disease program at Northwell Health?
I am a structural heart interventionalist and director of a program that specializes in structural heart procedures, both valvular heart disease and adult congenital heart disease. Our hybrid program encompasses a multidisciplinary team that includes structural interventionalists and cardiothoracic surgeons, in addition to imaging specialists, including computed tomography (CT) specialists, structural echocardiographers, and a whole host of physicians and health care practitioners to support this team. Procedures we perform include valve-in-valve implantation in any valve position, transcatheter aortic valve replacement (TAVR), mitral procedures, including MitraClip (Abbott Vascular) and some of the newer technologies for transcatheter mitral valve repair and replacement, including the Pascal device (Edwards Lifesciences) for repair and the Tendyne transcatheter mitral valve system (Abbott Vascular) for replacement, as well as an assortment of other procedures such as atrial septal defect closure, patent foramen ovale closure, paravalvular leak closure, ventricular septal defect closure, and left atrial appendage occlusion. Any non-coronary cardiac intervention is covered within our division. Furthermore, this division is housed within the department of cardiothoracic surgery.
Structural interventionalists work hand-in-hand with the surgeons, who, along with the patients and their referring physicians, make true multidisciplinary and shared decision-making a reality.
How long has your center been performing TAVR?
We were part of the original CoreValve U.S. pivotal trial, and have gone through the evolution of TAVR procedures in patients, starting from the inoperable and high-risk patients, transitioning to the intermediate risk, and most recently, incorporating low-risk patients in the CoreValve Evolut Low Risk trial/registry.
Can you discuss the most recent TAVR trial data presented at the American College of Cardiology (ACC)’s Scientific Sessions?
The low-risk data recently presented at ACC, both for PARTNER and CoreValve, is truly ground-breaking. The data is enlightening us as to how these transcatheter technologies can be applied to an entire disease state and not just isolated risk populations. It changes the story as to how we as a multidisciplinary team will approach patients with aortic stenosis. Patients will no longer undergo screening based on surgical risk; instead, they will be evaluated based on their anatomy and other comorbidities to determine their risk profile for transcatheter therapies. If a patient is considered high risk for TAVR, the question becomes whether surgery is the best option, and by using the most up-to-date imaging, how can we best optimize this surgical result.
Furthermore, we will need to ask, what is in the best interest of the patient over his or her lifetime? With younger, low-risk patients, we cannot think solely about the first valve implantation, but must consider what the next 10, 20, or 30 years will bring for patients in terms of their healthcare needs and what long-term treatment strategies will suit them best. This may include coronary re-access for patients with coronary artery disease, need for valve-in-valve implantation for biological failure and concerns over patient-prosthesis mismatch, altered anticoagulation regimens in patients with varied bleeding risk profiles, and management algorithms for conduction abnormalities related to TAVR. Overall, we use a shared decision-making format with the patient and our other practitioners to arrive at the best solution for each individual patient.
What is the imaging pathway for your TAVR patients?
All of our patients undergoing imaging assessment for aortic stenosis, irrespective of surgical risk, receive a transthoracic echocardiogram to evaluate valve hemodynamics, and a cardiac structural CT angiogram, as well as a CT angiography (CTA) of the abdomen and pelvis, to assess anatomy for valve sizing and transcatheter device determination, best access approach, and potential application for cerebral embolic protection. The CT angiography results and/or history of prior coronary artery disease will determine whether the patient needs a dedicated coronary angiogram. Many of our younger patients now forgo the invasive angiogram with our improved non-invasive workup.
Can you tell us how syngo TrueFusion (Siemens Healthineers) imaging co-registration is used in your patients?
During any structural heart procedure where a CTA cardiac structure has been performed prior, we overlay the CT onto the fluoroscopic image for intraprocedural guidance. In addition, when we do cases with intraprocedural transesophageal echocardiogram (TEE), we can utilize the TEE data and overlay that information onto the fluoroscopy image for added intraprocedural guidance. For TAVR, the majority of our cases are now done under conscious sedation so we typically won’t use TEE fusion imaging, but we routinely use overlay for CT-fluoro fusion imaging. Fusion imaging becomes particularly helpful for TAVR access, in conjunction with ultrasound guidance, and placement of cerebral embolic protection. In addition, our experience of fusion with mitral and tricuspid valve therapies is growing as the technologies continue to evolve in this space.
What other advantages are offered by the ability to have a CT overlay on fluoroscopy with syngo TrueFusion?
CT fusion imaging for TAVR allows us to obtain ideal iliofemoral access. You can choose a spot on the common femoral artery that is away from calcium and plaque in order to get an optimal access approach. For alternative access TAVR such as percutaneous subclavian, transcaval, extra-thoracic transinnominate, or even direct aortic, you can optimize entry by choosing the exact location in the artery or abdominal aorta for access, and use the CT overlay to guide you to that location. In addition, fusion imaging helps to obtain the optimal co-planar angle for deployment, particularly important when doing valve-in-valve procedures in patients with homografts or fluoroscopically-silent valves, as well as providing important information about the location of coronary arteries. Its ability to show a vascular roadmap of the great vessels for cerebral embolic protection has become increasingly important as we have increased our applications of this technology.
You are partnering with imaging companies such as Siemens Healthineers. Can you tell us about it?
Augmented imaging reality, or the use of fusion imaging within the catheterization laboratory, has been integrated into our structural heart workflow for years. As transcatheter technology evolves and we do more complex interventions on the heart, we need improved imaging information within the laboratory for decision making at the time of the procedure. The concept of fusion imaging has grown significantly; the quality of the data we are getting now, as compared to 10 years ago, helps us to perform our procedures successfully. We started with a focus on the valve outflow space and paravalvular leaks for procedural guidance, but now, as we move into the transcatheter mitral valve and tricuspid space, real-time image information is becoming of utmost value. These partnerships with our imaging companies are essential as we work to optimize outcomes and improve reproducibility.
Are you using syngo TrueFusion in all your valve procedures?
Yes, we have integrated this technology into our program for all structural heart interventions. It depends on the intervention, which will determine if it is a case utilizing TEE fusion imaging, CT fusion imaging, or a combination of both modalities (what we have termed triple fusion) that will be applied to the patient. It is in active use within our transcatheter mitral valve repair and replacement program. The mitral valve is not well visualized under fluoroscopy, and we feel the use of echocardiography and fusion imaging helps us to optimize procedural outcomes.
Do you use syngo TrueFusion during valve positioning?
Fusion imaging is valuable for valve positioning in TAVR, as well as in mitral, pulmonic, and tricuspid valve procedures. We have refined TAVR protocols to the point that fusion imaging has become less of a need; that being said, in select cases utilizing fusion imaging during TAVR has allowed us to use minimal to no contrast during valve deployment. This is particularly beneficial for cases using a retrievable TAVR valves. For the inflow valve space, everything is dependent upon imaging, whether it is TEE or fusion, to help position the valve in the appropriate location.
How has your pre-procedure planning for TAVR changed over time?
It has definitely evolved over the years, because of the improvement in transcatheter technologies, such as smaller access approaches and improved valve technologies. For TAVR, the pre-procedure planning process has been refined to the point where it has become much more efficient. We have streamlined scheduling and acquisition of testing and, within the multidisciplinary team, we are reviewing imaging in a more rapid, yet thorough, fashion. Extensive discussions around pre-procedure planning have now transitioned to other valve spaces that remain a continuous work in progress.
Will the use of CT be central for these decisions?
I do think CT imaging has the best image resolution to date to provide anatomic description and aid us in making procedural decisions. As CT imaging further improves, the anatomic information provided will get even better. That being said, we now have 4D magnetic resonance imaging (MRI) capabilities with improved imaging resolution. Currently, MRI is not to the same level as CT, but it has improved significantly over the years and now, with flow information, it does offer more insight into physiology and has become a great additive technology to our multimodality imaging.
Are there still imaging deficits that need to be addressed?
Each technology has its limitations, but as these technologies evolve, they become less and less. For example, echocardiography, whether it be transesophageal echo or intracardiac echo, needs to continue to improve field of view and image resolution to better visualize small catheters and wires, in addition to the large devices we put into the heart. For CT and fluoroscopy co-registration, an ability to merge multiple phases of the CT scan onto the x-ray will definitely help to improve intraprocedural guidance. For MRI, better image resolution will definitely be a step forward. Increasing our ability to utilize all imaging modalities in a standard manner will decrease the use of fluoroscopy and reduce the amount of radiation exposure within the room. Reducing radiation exposure to the patient and the operator is a necessary, vital goal as our profession continues to perform more and more complex cardiac interventions.
It sounds like the need for imaging will only grow.
In the past, surgeons would do open heart procedures, which were very invasive and complicated, with limited imaging. In collaboration with our surgeons, we see that they too are now using CT and additional imaging to help guide surgical interventions. Today, cardiovascular imaging is of the utmost importance to optimize our outcomes for minimally invasive heart surgery and transcatheter procedures. Moving forward, it is the imaging aspect of all disease states that should help us to decide the best therapeutic option(s) for the patient and guide our intraprocedural interventions, whether via an open surgical, hybrid, robotic, or purely transcatheter approach.
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This article is supported by Siemens Healthineers.
Disclosure: Dr. Chad Kliger reports speaking honorarium for Siemens Healthineers and Philips Healthcare, and speaking honorarium/consulting for Edwards Lifesciences and Medtronic.
Dr. Chad Kliger can be contacted at ckliger@northwell.edu.
