Background: The Initial Rational Dispersion of TAVR and The Next Transition

Transcatheter aortic valve replacement (TAVR) has become the dominant form of valve replacement for relief of aortic stenosis. Its release in the USA involved orchestrated events executed by the Food and Drug Administration (FDA), the Centers for Medicare and Medicaid Services (CMS), the device manufacturers, and the professional cardiology and cardiac surgery medical societies. The results of this partnership have been laudable as reflected by both the volume of TAVR procedures performed and the steady improvement in clinical outcomes.

A renewed discussion and debate are now ongoing as CMS reconsiders its national coverage determination (NCD), i.e., the coverage requirements for hospitals and physicians performing TAVR. The debates have valid scientific, ethical, and clinical dimensions that occur in the hyper-competitive US health care system, which pits hospitals and physicians against each other for market share, consumes almost 20% of gross domestic product, and produces large profits to device and pharmaceutical companies as a result of their pricing to US patients, which is the highest in the world [ , ].

The MEDCAC Meeting

The Medicare Evidence Development & Coverage Advisory Committee (MEDCAC) met in July 2018 to review the 2012 NCD for TAVR. The basis for the request was essentially twofold: first, to question the principle of a volume-quality relationship for TAVR and second, to contend that minimum volume requirements limit access to care. CMS will use the meeting discussion and votes to inform the agency’s decision on a possible NCD revision that will be published in draft form in March 2019. After public comment, the decision will be finalized by June 2019.

In this issue of Cardiovascular Revascularization Medicine, Rogers and colleagues summarized the MEDCAC meeting’s content [ ]. Their contribution is useful to understand the various issues and arguments but has some clear biases and is superficial on several issues. For example, they twice cite the fact that the professional societies presented data on volume-outcome that were “unpublished,” thus reducing its credibility, but they fail to point out that Dr. Martin Leon and industry also presented data that were unpublished. The rather precipitous and unexpected calling of the MEDCAC meeting resulted in all parties presenting preliminary and unpublished data.

The timing of MEDCAC was unfortunate, with much wasted energy on the contents and perceived impacts on the number of sites based on an earlier draft of the 2018 AATS/ACC/SCAI/STS Expert Consensus Systems of Care Document: Operator and Institutional Recommendations and Requirements for Transcatheter Aortic Valve Replacement. The final document was published just two weeks prior to the MEDCAC panel and reflected input of literally hundreds of external comments of stakeholders and cardiovascular experts [ ]. The goal of the 2018 update was to provide guidance and support for a large number of TAVR centers also offering surgical aortic valve replacement (SAVR) throughout the U.S. with a rational balance between patient access to TAVR-SAVR therapy and quality outcomes. The document furthermore outlines a pathway to increased reliance on validated quality metrics and decreased reliance on volume requirements as a mature and tiered national system of care for valvular heart disease (VHD) is developed with an accreditation process. A companion document outlining the tiered system of VHD care, the “2018 Systems of Care Document: A Proposal to Optimize Care for Patients With Valvular Heart Disease: A Report of the American College of Cardiology Task Force on Health Policy Statements and Systems of Care,” is now in press [ ].

The MEDCAC Meeting

The Medicare Evidence Development & Coverage Advisory Committee (MEDCAC) met in July 2018 to review the 2012 NCD for TAVR. The basis for the request was essentially twofold: first, to question the principle of a volume-quality relationship for TAVR and second, to contend that minimum volume requirements limit access to care. CMS will use the meeting discussion and votes to inform the agency’s decision on a possible NCD revision that will be published in draft form in March 2019. After public comment, the decision will be finalized by June 2019.

In this issue of Cardiovascular Revascularization Medicine, Rogers and colleagues summarized the MEDCAC meeting’s content [ ]. Their contribution is useful to understand the various issues and arguments but has some clear biases and is superficial on several issues. For example, they twice cite the fact that the professional societies presented data on volume-outcome that were “unpublished,” thus reducing its credibility, but they fail to point out that Dr. Martin Leon and industry also presented data that were unpublished. The rather precipitous and unexpected calling of the MEDCAC meeting resulted in all parties presenting preliminary and unpublished data.

The timing of MEDCAC was unfortunate, with much wasted energy on the contents and perceived impacts on the number of sites based on an earlier draft of the 2018 AATS/ACC/SCAI/STS Expert Consensus Systems of Care Document: Operator and Institutional Recommendations and Requirements for Transcatheter Aortic Valve Replacement. The final document was published just two weeks prior to the MEDCAC panel and reflected input of literally hundreds of external comments of stakeholders and cardiovascular experts [ ]. The goal of the 2018 update was to provide guidance and support for a large number of TAVR centers also offering surgical aortic valve replacement (SAVR) throughout the U.S. with a rational balance between patient access to TAVR-SAVR therapy and quality outcomes. The document furthermore outlines a pathway to increased reliance on validated quality metrics and decreased reliance on volume requirements as a mature and tiered national system of care for valvular heart disease (VHD) is developed with an accreditation process. A companion document outlining the tiered system of VHD care, the “2018 Systems of Care Document: A Proposal to Optimize Care for Patients With Valvular Heart Disease: A Report of the American College of Cardiology Task Force on Health Policy Statements and Systems of Care,” is now in press [ ].

Volume Thresholds and Quality of Care

TAVR is a high-end cardiovascular procedure that requires skilled teams and significant institutional resources to produce optimal outcomes and benefits to patients. There is irrefutable evidence gleaned from the STS/ACC TVT Registry for both a learning curve-volume relationship and yearly case volume relationship and risk-adjusted mortality during the initial 5-year period after TAVR commercial release [ , , ]. Additional important analysis of the volume-outcome relationship in TAVR from the TVT registry data is underway using data from current practices and technologies that hopefully can be fast-tracked for peer-review publication for CMS scrutiny prior to their finalizing an updated TAVR NCD.

The quality of a single low-volume site, however, cannot accurately be assessed due to statistical uncertainty discussed in detail in the consensus document, at the MEDCAC panel, and in a recent Dehmer commentary [ ]. Utilizing 3-year rolling data from an individual site will help mitigate this quality evaluation conundrum. The planned development of composite measures of TAVR quality incorporating bleeding, stroke, and vascular complications in addition to 30-day and 1-year risk-adjusted mortality will further enable better assessment of quality. Additional planned metrics such as “alive and improved at one-year” incorporating patient-reported outcomes from the Kansas City Cardiomyopathy Questionnaire (KCCQ) will even further enhance our quality assessment of overall VHD care and patient selection.

Rogers and colleagues also minimize mortality differences between sites with low and high volumes despite their statistical significance. An absolute 1% difference in mortality should not be trivialized and may represent a doubling of mortality rate.

Since the MEDCAC panel, Wassef and colleagues [ , ] further corroborated the learning curve and volume-outcome relationship in TAVR with patient data gleaned from sites representing three continents. All-cause mortality was significantly higher in the low-volume compared with the high-volume (8.8% vs. 3.9%; p=0.003) centers. The early safety endpoint was worse for low-volume sites (34.3% vs. 26.4%; p=0.01), as well as major bleeding (11.1%, vs. 4.9%; p = 0.037).

Patients, families and clinicians alike intuitively appreciate the volume-quality relationship. This is apparent whether admiring Stephen Curry’s basketball acumen, a concert violist, or a professional golfer — skills honed by hours of practice. It is why the patient, family and the referring clinician typically ask or know the answer to the question, “How many of these do you do?”

The different justification of volume thresholds for SAVR and PCI is not well-articulated in the Rogers review. A good surgical program is needed to provide many patients with the SAVR option. Secondly, surgical expertise is critical during TAVR when things do not go well with perforations, ischemia, shock, and other problems needing a surgical solution. High-risk PCI in patients with critical aortic stenosis — often necessary prior to TAVR — is an inappropriate procedure for either low-volume PCI operators or low-volume PCI hospitals. Likewise, acute coronary occlusion during TAVR and future PCIs that must be performed through TAVR struts are also not for low-volume operators. These volume thresholds have the goals of being sure sites can provide these services with some assurance of quality. It is challenging coming up with exact volume thresholds and quality indicators to achieve these goals.