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| Introduction |
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| See Appendix for disclosures regarding authors financial relationships with industry.
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| Preamble |
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| 1. Introduction |
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Catheter-based therapies present new and potentially transformational technology for valvular and structural heart disease (2). The associated issues are complex, with multiple stakeholders: first and foremost, the patients receiving this therapy, but also including clinicians, inventors, industry, regulatory agencies, government and private payers, and professional societies. The purpose of this document is to capture all the core elements proportionally with the overarching goal of aligning the interests of all expert physicians including cardiologists; proceduralists; heart valve, heart failure, and imaging specialists; and imaging experts with other relevant stakeholders (regulators, payers, professional societies) in delivering the best possible patient-centered care. The role of societies is to realize this goal through ongoing development of expert consensus statements, guidelines, credentialing criteria, and training paradigms, thereby ensuring responsible diffusion of this technology.
1.1 Components of New Valve Technology Introduction
Several issues emerge with the introduction of this new technology.
These complexities are compounded by the multiple constituents involved—patients, competing physicians and practice centers, payers, and industry—each of which may have different goals. The intent of this document is to provide a platform of issues to be solved and provide some direction as to how this may be accomplished.
| 2. Heart Valve Surgery and Transcatheter Valve Therapy |
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Other issues with traditional aortic and mitral valve surgery include the fact that patients may not even be offered operation; in multiple series from different centers and in different countries, up to 40% of patients with severe aortic stenosis are treated medically (4–6). Some of these patients may be too sick because of associated medical comorbidities, and some may be considered too old to be offered surgery. Finally, some who may benefit the most from an operation may decline surgery even though they develop irreversible damage from the valve lesion that could have been treated.
These factors have led to the continuous development of less invasive strategies in an attempt to preserve the well-documented, long-term efficacy of standard procedures with lower mortality, lower morbidity, and less invasiveness. Such an improved risk-benefit ratio would result in a therapy that could be applied to more patients, as well as earlier in the course of their specific disease process. A critical question is whether there is a change in the risk-benefit ratio with these new therapies that is key to the multiple stakeholders—most importantly, patients and their families.
For these less invasive approaches to work and to be introduced in a rational, balanced, and least disruptive manner, a number of critical elements must be brought together (Table 1). Successful implementation of these principles and practices will, in our opinion, maximize the chances for the successful introduction of this new technology and treatment paradigms, ensuring greatest patient benefit.
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This heart team concept has been extended to valvular heart disease. In PARTNER (Placement of AoRTic TraNscathetER Valve Trial), the pivotal U.S. trial of a new device for transcatheter aortic valve replacement (TAVR), patients are routinely evaluated by "partners" of cardiologists and surgeons together to determine patient eligibility and optimal treatment strategy (9). This requires pre-procedural evaluation in valvular heart disease clinics, multidisciplinary team conferences, and joint performance of the procedure, as well as postoperative care. This same heart team principle has also proven to be extremely successful in centers participating in the U.S. pivotal trial of the first catheter-based approach for the treatment of mitral valve disease, EVEREST II (Pivotal Study of a Percutaneous Mitral Valve Repair System) (10). Such a heart team will be even more critical as the issues with structural heart disease become more complex, as the treatment expands to more centers, and as new technology is applied outside of the constraints of randomized clinical trials. The success of this team concept has been demonstrated in heart transplant centers in which patient treatment decisions and care are managed by heart failure cardiologists, transplant and ventricular assist device surgeons, experts in immunosuppression, as well as specialists in echocardiography and in anesthesia; all collaborate as a multidisciplinary team. Key members of the multidisciplinary team for structural heart valve disease management include primary cardiologists, interventional cardiologists, cardiac surgeons, noninvasive and heart failure cardiologists, echocardiographers and cardiac imaging specialists, cardiac anesthesiologists, nurse practitioners, physician assistants, research coordinators, administrators, dietary and rehabilitation specialists, and social workers. Each component will need to develop and implement specific protocols depending on the individual patient and specific technical procedure.
2.1.1 The Role of the Primary Cardiologist
Typically, patients who are candidates for these procedures have been seen longitudinally in the course of their disease by primary cardiologists who have a unique perspective of patient and family dynamics. These physicians coordinate care, ensure complete evaluation, order and evaluate diagnostic studies, implement medical care, and ensure involvement of patients and families in the decision-making process. These primary cardiologists also resume care of the patient after the procedure and need to be cognizant of the follow-up needs and protocols; accordingly, these individuals are an essential component of the heart team to enhance patient-centered care. Primary cardiologists in concert with the surgeons and interventional cardiology teams will be central in applying scoring systems to evaluate risk-benefit profiles in this diverse group of patients (11,12). The patient's values and goals need to be central in benefit-risk assessment and treatment decisions.
2.1.2 Imaging Specialists
Mandatory imaging modalities necessary for a structural heart disease program include 2- and 3-dimensional transthoracic and transesophageal echocardiography, vascular computerized tomography with 3-dimensional reconstruction, cardiac magnetic resonance imaging, diffusion-weighted magnetic resonance imaging of the brain, and transcranial Doppler imaging.
Echocardiography will be critical, with collection of standardized definition sets. Such data will be best defined by large-scale registries such as the STS National Adult Cardiac Database and the American College of Cardiology-National Cardiovascular Data Registry (ACC-NCDR). The Valve Academic Research Consortium (VARC) Consensus Report, which established standardized endpoint definitions for transcatheter aortic valve therapy, is the first step in this direction (13). The American Society of Echocardiography (ASE) has developed specific definitions of severity of valvular lesions that could benefit from transcatheter valve therapy that will need to be incorporated in registry reporting (14,15).
An important screening component involves 3-dimensional reconstruction of the aortoiliac vasculature using multislice computerized tomography (MSCT). The current aortic transvalvular device delivery sheaths are large, ranging from 18- to 24-Fr in diameter. Although they are becoming smaller in diameter, access remains an issue. Accordingly, it is essential to identify absolute arterial diameters and specific abnormalities such as severe calcification or tortuosity of the aortoiliac vascular tree that may dictate an alternative access route.
2.1.3 Heart Failure Specialists
An increasing number of patients with advanced valvular heart disease have a component of left ventricular dysfunction. For patients with aortic stenosis, left ventricular dysfunction may render the assessment of the severity of the aortic stenosis difficult, thus complicating decision making about the need for or performance of a procedure. In addition, heart failure specialists will need to help assess the potential for reversibility of left ventricular dysfunction following TAVR. This will also be of particular importance for the treatment of mitral valve disease. Identification of appropriate patients with mitral insufficiency and heart failure who may benefit from a catheter-based approach is best accomplished by consultation with heart failure specialists.
2.2 Specialized Experienced Facilities
2.2.1 Regional Heart Centers
The concept of regional heart centers will be extremely important. Because of the myriad of specialists, imaging equipment, procedural facilities, and support infrastructure necessary to build a valve center, it is unlikely that accessibility to new transcatheter valve technology will be universal and immediate. In the United States, many cardiac surgical centers and catheterization laboratories have a very low volume of structural heart disease cases. In these centers, for example in patients with mitral regurgitation, mitral valve replacement is more frequently performed than is mitral valve repair, which is the preferred strategy (16). Outcomes for patients undergoing surgery for valvular heart disease have clearly been demonstrated to be related to center procedural volume (17). In England, Centers of Excellence with specific volume criteria for treatment of mitral valve disease have been proposed by the National Institutes for Health and Clinical Excellence (NICE) (18). The complexities of the management of valvular heart disease will require the infrastructure available only in regional referral centers with appreciable patient volume in valvular heart disease. The development of specialized regional centers will be controversial; a tenet of modern cardiovascular practice has been that each hospital that has experienced personnel should be able to do any and all indicated procedures. However, in the case of percutaneous valve repair/replacement, the specialized expertise, experience, imaging equipment, and facilities that will be required to optimize outcomes are not available in all programs. The analogy to regional transplant referral centers is apropos. Although access to care should not be as limited as it is with cardiac transplantation, patient populations will not be best served being treated in multiple institutions with relatively low volumes in the same geographic region. It must be remembered that the initial results of the first randomized trial of TAVR were achieved by a heart team of experienced surgeons and structural interventional cardiologists working together in high-volume tertiary care centers. We believe that the criteria for regulatory approval and reimbursement by the appropriate federal agencies should initially be based on similar criteria in terms of expertise and high valve procedure volumes in new, approved centers.
In order for this approach of specialized regional centers to be implemented, detailed lists of facilities and personnel experience in addition to pre- and post-procedural care protocols, as well as complication management strategies, must be developed and then implemented. An analogy to this approach may be the New York State Department of Health program for performance of primary percutaneous coronary intervention centers without onsite surgery that has set up specific requirements with physician oversight, periodic review, and feedback (19). Key to this program, all data must use standardized forms and be sent to a central data registry for reporting. A similar national central data repository needs to be constructed for valve therapy.
2.2.2 Procedure Setting: Modified Catheterization Laboratory and Hybrid Operating Room
Two major approaches have been developed, both with specific advantages and specific proponents. The core tenet of both is that superior imaging is mandatory. In addition, sterility is of paramount importance.
2.2.2.1 Modified Conventional Cardiac Laboratory
This approach can utilize a conventional cardiac catheterization laboratory with some modifications. A specific drawback is the size of the conventional catheterization room, which is typically 600 square feet. Such a room can support conventional angiography and percutaneous coronary intervention. In addition, for treatment of some types of structural heart disease, these conventional rooms can also be used as such for closure of a patent foramen ovale, a paravalvular leak, and a left atrial appendage occlusion, although for each of these procedures, the rooms typically need to have biplane imaging equipment and be integrated with real-time echocardiography procedural guidance. A modified room of this design can also be used for hybrid surgical procedures where the left internal mammary artery is placed to the left anterior descending, and the remaining stenoses are treated percutaneously. For transcatheter valve therapy, the room needs to be large enough to accommodate anesthesia equipment, echocardiography machines, intra-aortic balloon pumps, and cardiopulmonary bypass machines. If a conventional cardiac catheterization laboratory is to be used, adaptation to meet surgical sterility standards including airflow exchanges is essential.
2.2.2.2 Hybrid Operating Room
Another type of surgical "hybrid" room has attracted great interest. These are rooms that are focused on newer procedures such as percutaneous aortic and pulmonary valve implantation, hybrid percutaneous/surgical coronary and valve/coronary procedures, and some composite hybrid aortic arch and descending thoracic and abdominal aortic approaches with aortic stent grafts. These rooms are typically larger (800 to 900 square feet) than hybrid coronary angiographic rooms. Catheterization laboratory–quality X-ray imaging is a requisite but is supplemented by a variety of alternative imaging modalities, particularly transesophageal echocardiography and 3-dimensional intravascular ultrasound images. In addition, other technologies, such as rotational angiography, computed tomography (CT), or at the very least, real-time interactive access to magnetic resonance imaging and CT images, need to be available because these newer imaging modalities are expected to play a larger role in the field with real-time 3-dimensional reconstruction of CT images and "road-mapping" of important structures.
An important, yet unresolved issue is the location of these new-generation hybrid rooms. Placement of the new hybrid rooms in an operating room suite environment affords accessibility to the operating suite infrastructure and personnel, whereas placement in the catheterization laboratory provides wider availability to catheterization laboratory personnel and catheter-based equipment. These are important issues because hybrid teams may have very different skill sets if they come from the background of surgery, whereas a hybrid team with a background of interventional cardiology may not have the same skill set. Maintenance of separate teams may not be efficient. Alternatively, cross-training 1 team may dilute the experience. Current procedural teams function best with both disciplines involved and with both catheterization laboratory and operating room personnel participating. No matter where the procedural room is located—catheterization laboratory or operating suites—equal access by both specialties is required.
The location of patient care post-procedure is of considerable importance. Coronary care units are very experienced with hemodynamic assessment but are not accustomed to dealing with very large-bore catheter- and sheath-vessel access issues nor surgical incisions and chest drainage tubes. In addition, surgical units are most accustomed to dealing with the rapidly changing hemodynamics occurring after aortic valve replacement. This part of the field will continue to evolve as the technology becomes smaller with percutaneous vascular access closure devices. It will be important to centralize the immediate post-procedural care of these patients in 1 location on a single clinical service at the individual center to maximize expertise, team training, and the development of clinical protocols.
| 3. Scientific Literature |
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The pivotal PARTNER trial has received a great deal of interest. Specific details about patient selection, protocols used, endpoints, and statistical evaluation are crucial.
The PARTNER trial was basically 2 parallel trials that enrolled the highest-risk patients ever seen in any cardiovascular trial by virtue of their age and severity of comorbid conditions: 1) PARTNER Cohort A, which randomized high-risk surgical patients to either traditional aortic valve replacement or to TAVR by either a transfemoral or transapical approach; and 2) PARTNER Cohort B in which patients who were inoperable were randomized to either a TAVR by a transfemoral approach or to conventional medical therapy, which typically consisted of balloon aortic valvuloplasty. Screening required an evaluation by 2 experienced cardiac surgeons to agree on the surgical risk using the STS Predicted Risk of Mortality score (20) and was rigorous, with approximately one quarter to one third of screened patients subsequently enrolled. The primary endpoint was death from any cause at 1 year.
The results of PARTNER Cohort B have recently been published (9) and included 358 patients deemed unsuitable for conventional aortic valve replacement because of predicted probability of
50% mortality or at risk for a serious irreversible complication by 30 days. At 1 year, all-cause mortality with TAVR was 30.7% versus 50.7% with medical therapy (hazard ratio: 0.55, 95% confidence interval: 0.40 to 0.74). Despite the marked improvement in survival and event-free survival, there were some significant safety hazards, particularly a higher incidence of major strokes (5.0% versus 1.1%) as well as increased major vascular complications (16.2% versus 1.1%) with TAVR, both of which may impact early and longer-term outcome adversely. Longer-term outcomes will be required.
These results were received enthusiastically; however, they have important implications. First, they can be applied only in patients similar to those in the study (i.e., those patients deemed to be inoperable). Second, they are the result of treatment by very experienced operators working as a heart team in a hybrid operating room or similar facility with a specific device and do not necessarily apply to other devices.
The preliminary results of the PARTNER Cohort A trial were presented and, when published, will also have important implications. The primary endpoint of the trial was met, with TAVR found to be noninferior to aortic valve replacement for all-cause mortality at 1 year (TAVR versus aortic valve replacement, 24.2% versus 26.8%, respectively, p=0.001 for noninferiority). Death at 30 days was lower than expected in both arms of the trial: TAVR mortality (3.4%) was the lowest reported in any series, despite an early generation device and limited previous operator experience. Aortic valve replacement mortality (6.5%) was lower than the expected operative mortality (11.8%). Furthermore, both TAVR and aortic valve replacement were associated with important but different peri-procedural hazards: major strokes at 30 days (3.8% versus 2.1%, p=0.20) and 1 year (5.1% versus 2.4%, p=0.07), and major vascular complications were more frequent with TAVR (11.0% versus 3.2%, p<0.001). Major bleeding (9.3% versus 19.5%, p<0.001) and new onset atrial fibrillation (8.6% versus 16.0%, p<0.001) were more frequent with aortic valve replacement.
The trial investigators also concluded that "a multidisciplinary valve team approach benefits patients and is recommended for all future valve centers." These results cannot be extrapolated to evaluate the outcome of this procedure in patients who are excellent candidates for conventional aortic valve replacement. For this to occur, more randomized controlled studies will need to be performed.
The 30-day mortality in PARTNER Cohort A (3.4%) and PARTNER Cohort B (5.2%) is better than published European registry mortality (8.5%) (21–23). This raises questions about the "generalizability" of these trial results after commercialization in the United States. Responsible diffusion of this technology with close monitoring of outcomes after commercialization will be critical to maintain these results. The incidence of neurologic events (5.5% at 30 days, 8.3% at 1 year) and major vascular complications (11%) that occur in patients undergoing TAVR also needs to be addressed. The role of embolic protection, smaller delivery systems, and post-procedure anticoagulation remains to be determined.
The other completed pivotal randomized trial is the EVEREST II trial of the MitraClip, which randomized patients with severe mitral regurgitation to surgery or a catheter-based approach. The MitraClip was used to perform an "Alfieri-type" approximation of the free edges of the mitral leaflets for the treatment of either functional mitral regurgitation due to annular dilation or structural mitral regurgitation due to mitral leaflet abnormalities (10). Although less effective at reducing mitral regurgitation, percutaneous repair was associated with superior safety and comparable improvements in clinical outcomes at 12 months compared with mitral valve surgery (10).
| 4. Technological Improvement |
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The situation is even more complex for the transcatheter mitral valve approaches. Some of these will involve using percutaneous technology to create the equivalent of an Alfieri stitch to treat structural mitral regurgitation. Others will involve manipulation of catheters to deliver energy to shrink the mitral annulus or to deliver a variety of bands to decrease the diameter, as well as other approaches that will be combined. Again, each of these approaches will have specific device deployment issues and considerations. Some of these new technologies and deployment approaches will be aimed at expanding either the number or types of valves that can be treated successfully; some of these will make the procedure easier. The number of new devices, however, will contribute to the growing complexity of the field.
| 5. Operator Training |
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The creation of clinical fellowships for training in transcatheter valves is also quite problematic at the current time. Since there is not commercial approval for any aortic or mitral device in the United States, the potential for training exists only in current trial centers. There are only 30 to 40 centers currently with experience in transcatheter aortic valves and approximately 20 centers with transcatheter mitral valves. The procedure volume at each of these centers is currently limited by the constraints of trial enrollment, and experience at the senior staff level is limited, which further constrains fellowship training. The most advantaged individuals for transcatheter valve training are those who are currently fellows in programs that are trial centers. The training of other individuals, especially those who have completed their fellowships and are currently in practice, is also currently being addressed by our societies. The questions being asked include: What is the requisite experience to gain the necessary expertise to be proficient in the procedures? What is the length of training necessary to gain proficiency? Are 3-month fellowships sufficient, or do they need to be 6 months or 1 year? How are these fellowships to be funded? Is 1 common training pathway sufficient for cardiologists and surgeons alike, or are there different fellowships with some commonality? Should cardiologists and surgeons interested in being trained in valvular heart disease be trained as teams?
In our opinion, the professional societies should assume the leading role in establishing the minimal performance criteria and helping to build the infrastructure for these fellowships. Abrogating the responsibility for training to commercial sponsors who have a regulatory responsibility for training in their devices is not sufficient. The establishment of these criteria is beyond the scope of this document; however, the appropriate committees in the professional societies are currently establishing operator and institutional requirements for transcatheter valve performance.
| 6. Protocols for Care |
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| 7. Assessment of Outcomes |
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| 8. Summary |
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In order to address the challenges ahead for the responsible diffusion of this innovative transformational technology, it is critical that the professional societies, industry, payers, and regulatory agencies work together. The leadership of the ACCF and STS in consultation with multiple leaders within the primary and interventional cardiology and cardiac surgical communities, regulators, and payers make the following recommendations (Table 2).
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| Appendix |
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This table represents the relationships of committee members with industry and other entities that were determined to be relevant to this document. These relationships were reviewed and updated in conjunction with all meetings and/or conference calls of the writing committee during the document development process. The table does not necessarily reflect relationships with industry at the time of publication. A person is deemed to have a significant interest in a business if the interest represents ownership of 5% or more of the voting stock or share of the business entity, or ownership of $10,000 or more of the fair market value of the business entity; or if funds received by the person from the business entity exceed 5% of the person's gross income for the previous year. Relationships that exist with no financial benefit are also included for the purpose of transparency. Relationships in this table are modest unless otherwise noted.
| Footnotes |
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STS requests that this document be cited as follows: Holmes DR Jr, Mack MJ. Transcatheter valve therapy: a professional society overview from the American College of Cardiology Foundation and The Society of Thoracic Surgeons. Ann Thorac Surg 2011;92:380-9.
Reprints are available from Elsevier Inc, Reprint Department, FAX: 212-633-3820; e-mail: reprints{at}elsevier.com.
Permissions: Multiple copies, modification, alteration, enhancement, and/or distribution of this document are not permitted without the express permission of STS. Please contact healthpermissions{at}elsevier.com.
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