Cardiology

Mack, M., M. Hamandi and A. Gopal (2019). “TAC for TAVR: What Is the Score?” JACC Cardiovasc Imaging 12(1): 133-134.

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Abstract not available.

Mack, M. and M. Hamandi (2019). “Why Surgical Risk Algorithms Are Not Predictive of Transcatheter Aortic Valve Replacement Outcomes!” Circ Cardiovasc Interv 12(1): e007560.

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At least 12 risk algorithms have been constructed in various populations and differing periods to predict outcomes after surgical aortic valve replacement (SAVR). The 2 most widely used are the LES and the STS Predicted Risk of Mortality. The LES was developed in 1995 as an additive score (Additive EuroSCORE) and later converted to a logistic regression model. It was derived from a data set from 8 European countries and was based on a population sample of almost 15,000 patients undergoing all types of cardiac operations. There were 12 covariates identified that were predictive of early mortality in SAVR. The benefit of the LES is its user-friendliness, in that it requires only 18 data fields for the calculation. The shortcoming is that the algorithm is calculated on a relatively small sample size of a diverse set of cardiac operations from nearly 25 years ago. The LES has been repeatedly demonstrated to over-predict actual risk in the assessment of patients for whom surgery poses a high risk in the case of SAVR by a factor of 3. The STS Predicted Risk of Mortality has been more reflective of actual outcomes because it is SAVR specific (versus all cardiac surgical procedures) and based on more current data. An updated risk predictor, EuroSCORE II, was derived from more than 22 000 patients operated on in 2010 in 43 countries worldwide. It includes all cardiac procedures and now has 18 covariates predictive of surgical aortic valve mortality. Whether the accuracy of the EuroSCORE II model has been improved is a subject of debate. A renewed and intense interest has developed in predictive modeling for the management of patients with aortic stenosis because of the introduction of TAVR. When first introduced into clinical practice, TAVR was performed in the highest surgical risk patients. LES and STS Predicted Risk of Mortality were the 2 most common tools used for defining these high surgical risk patients and hence, were widely adopted for TAVR patient selection. However, it should not be surprising that the surgical risk scores have proven to be inaccurate for TAVR because of the fact that the risk algorithms were developed for one procedure and are being applied to a different one. Not only were the risk models neither developed nor validated for TAVR, but they do not take into consideration variables that may play a significant role in risk, including porcelain aorta, previous radiation therapy, liver disease, and frailty since the incidence of those factors were so low in the surgical population in which they were developed and validated. However, these risk scores have used because until now, because they were the best available. In 2016, a TAVR-specific risk model for in-hospital mortality was published. This model was based entirely on TAVR patients included in the STS/American College of Cardiology Transcatheter Valve Registry from 2011 to 2014. It was derived from a patient population of 13,718 and validated on 6,868 different patients in a subsequent time period. It included all commercially available valves in the United States and used 9 variables to predict in-hospital mortality with a C-statistic of 0.66. This is now in the process of being updated to predict 30-day and 1-year mortality after TAVR. (Excerpt from the introduction to, Taratini, G., et al., One-Year Outcomes of a European Transcatheter Aortic Valve Implantation Cohort According to Surgical Risk, Circ Cardiovasc Interv. 2019 Jan;12(1):e006724.)

Grayburn, P. A., A. Sannino and M. Packer (2018). “Proportionate and Disproportionate Functional Mitral Regurgitation: A New Conceptual Framework That Reconciles the Results of the MITRA-FR and COAPT Trials.” JACC Cardiovasc Imaging Dec 6. [Epub ahead of print].

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Traditional approaches to the characterization of secondary or functional mitral regurgitation (MR) have largely ignored the critical importance of the left ventricle (LV). We propose that patients with secondary MR represent a heterogenous group, which can be usefully subdivided based on understanding that the effective regurgitant orifice area (EROA) is dependent on left ventricular end-diastolic volume (LVEDV). According to the Gorlin hydraulic orifice equation, patients with heart failure, an LV ejection fraction of 30%, an LVEDV of 220 to 250 ml, and a regurgitant fraction of 50% would be expected to have an EROA of approximately 0.3 cm(2) independent of specific tethering abnormalities of the mitral valve leaflets. The MR in these patients is proportionate to the degree of LV dilatation and can respond to drugs and devices that reduce LVEDV. In contrast, patients with EROA of 0.3 to 0.4 cm(2) but with LVEDV of only 160 to 200 ml exhibit degrees of MR that are disproportionately higher than predicted by LVEDV. These patients appear to preferentially benefit from interventions directed at the mitral valve. Our proposed conceptual framework explains the apparently discordant results from 2 recent randomized controlled trials of mitral valve repair. The MITRA-FR (Percutaneous Repair with the MitraClip Device for Severe Functional/Secondary Mitral Regurgitation) trial enrolled patients who had MR that was proportionate to the degree of LV dilatation, and during long-term follow-up, the LVEDV and clinical outcomes of these patients did not differ from medically-treated control subjects. In comparison, the patients enrolled in the COAPT (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional Mitral Regurgitation) trial had an EROA approximately 30% higher but LV volumes that were approximately 30% smaller, indicative of disproportionate MR. In these patients, transcatheter mitral valve repair reduced the risk of death and hospitalization for heart failure, and these benefits were paralleled by a meaningful decrease in LVEDV. Thus, characterization of MR as proportionate or disproportionate to LVEDV appears to be critical to the selection of an optimal treatment for patients with chronic heart failure and systolic dysfunction.

Giri, J. S., M. Szerlip, C. Devireddy, D. A. Cox, C. Kavinsky, P. Genereux, S. S. Naidu, C. Bruner, J. Struck, J. Kurz and J. Dunham (2019). “SCAI 2018 Think Tank Proceedings: “What should the role of the surgeon be in TAVR, both as a co-operator and in-patient evaluation for TAVR?” Catheter Cardiovasc Interv 93(1): 178-179.

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The Society for Cardiovascular Angiography and Interventions (SCAI) Think Tank is held annually bringing together expert opinion from interventional cardiologists, administrative partners, and select members of the cardiovascular industry community in a collaborative venue. During the SCAI 2018 Scientific Session, topics in interventional cardiology felt to be relevant to the contemporary practice of the field were identified with the goals of defining the state of the field, current challenges, and future directions. . . Consensus emerged around several points relevant to the specific questions outlined above: 1. Preoperative evaluation by the heart team should remain intact. However, the group felt that the appropriate preprocedure evaluation should consist of a cardiac surgeon and a cardiologist who are both experienced in evaluating patients for TAVR. There was consensus that the current mandate of “TAVR clearance” based on the judgment of two cardiac surgeons is redundant and outdated. Given the equipoise between traditional surgical AVR and TAVR in a growing proportion of cases that is likely to include even low‐risk cases in the near future, it was felt that patients needed to participate in a shared decision‐making model involving a balanced discussion of risk and benefit involving both specialties rather than a perspective from only two cardiac surgeons, who may or may not be familiar with the pros and cons of TAVR. 2. The specialty of a TAVR operator is less important than his/her ability to both evaluate the potential TAVR patient and technically perform the case in a competent fashion. Rather than emphasizing which specialty should be present in the operating room or procedure suite, the group felt that the most important issue was assuring that any operators nominally performing the procedure have both the requisite training and experience to meaningfully contribute to the planned procedure. 3. Given continual advances in the procedure mentioned above, the concept of TAVR continuing to be a mandated two‐operator procedure appears to be a case of “swimming against the tide.” Thus, consensus was reached to recommend against a mandatory 62‐modifier code for TAVR going forward. Rather, an optional 62‐modifier could be used when physicians from two different specialties participated in the procedure or an 82‐modifier when physicians from the same specialty work together. This would allow for either a single operator or two operators from the same or different specialties to perform the TAVR procedure, with potential cost savings in the former scenario. 4. Instead, an optional 62‐modifier code could be used similar to what is done in other procedures in which “co‐surgeons” are deemed necessary to complete a complex procedure. The optional 62‐modifier could be used when physicians from two different specialties participated in the procedure or an 82‐modifier when physicians from the same specialty work together. This would allow for either a single operator or two operators from the same or different specialties to perform the TAVR procedure. Additionally, the heart team evaluation could determine which specific TAVR procedures may benefit from “co‐operators” and which would have good results with a single operator. Importantly, in cases where two operators are deemed advantageous, the heart team would choose the most appropriate two operators to successfully perform the case, regardless of specialty. (Excerpts from text, p. 178-179; no abstract available.)

Elsaid, O., V. Gulati, K. Tecson, M. Friedman and J. Kluger (2018). “Ventricular electrical delay as a predictor of arrhythmias in patients with cardiac resynchronization implantable cardioverter defibrillator.” Scand Cardiovasc J Dec 20: 1-16. [Epub ahead of print].

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BACKGROUND: Left ventricular (LV) remodeling and clinical response to cardiac resynchronization therapy (CRT) is inversely related to electrical dyssynchrony, measured as LV lead electrical delay (QLV). Presence of atrial or ventricular arrhythmia is correlated with worsening heart failure and LV remodeling. OBJECTIVE: We sought to assess the association of QLV with arrhythmic events in CRT recipients. METHODS: We identified patients implanted with a CRT device at our center. QLV interval was measured and corrected for baseline QRS (cQLV). We performed multivariable Logistic regression to assess the effect of cQLV on the occurrence of atrial/ventricular arrhythmic events. RESULTS: Sixty-nine patients were included in analyses. The cQLV was significantly shorter in patients with atria tachycardia/supraventricular tachycardia (AT/SVT) events compared to patients without AT/SVT events (43.4 +/- 22% vs. 60.3 +/- 26.7%, P = 0.006). In contrast, no significant difference in cQLV was observed between patients with and without ventricular tachycardia/fibrillation (VT/VF) events (46.2 +/- 25.4% vs. 56 +/- 25.7%, P = 0.13). cQLV was significantly shorter in patients with new onset AT/SVT events compared to those without (38.3 +/- 22.2% vs. 55.7 +/- 25.7%, P = 0.028). In contrast, no significant difference in cQLV was observed between patients with and without new onset VT/VF events (44.2 +/- 25.2% vs. 56.3 +/- 25.5%, P = 0.069). Following adjusted analyses, cQLV was a significant predictor of AT/SVT, but not for VT/VF. CONCLUSION: cQLV is a simple measure that can identify a vulnerable cohort of CRT patients at increased risk for atrial tachyarrhythmias, and hence can predict reverse remodeling and clinical response to CRT treatment.