Cardiology

Gelijns, A. C., A. J. Moskowitz, P. T. O’Gara, G. Giustino, M. J. Mack, D. M. Mancini, E. Bagiella, J. Hung, G. Ailawadi, M. B. Leon, M. A. Acker, J. H. Alexander, N. W. Dickert, W. C. Taddei-Peters and M. A. Miller (2021). “Transcatheter mitral valve repair for functional mitral regurgitation: Evaluating the evidence.” J Thorac Cardiovasc Surg 162(5): 1504-1511.

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OBJECTIVES: Two trials (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional Mitral Regurgitation Trial and Percutaneous Repair with the MitraClip Device for Severe Functional/Secondary Mitral Regurgitation Trial) were published in 2018 evaluating the effectiveness and safety of transcatheter repair for patients with heart failure with significant functional mitral regurgitation, which yielded different results. This article reviews the strength of the evidence, differences in trial designs, ethical and implementation implications, and delineates future research needs to help guide the appropriate dissemination of transcatheter repair for functional patients with mitral regurgitation. METHODS: The National Heart, Lung, and Blood Institute convened a workshop of interdisciplinary experts to address these objectives. RESULTS: Transcatheter repair of functional mitral regurgitation can provide significant benefits in terms of heart failure hospitalizations, survival, and quality of life when appropriate heart failure candidates with moderate to severe or severe mitral regurgitation while on optimal guideline-directed medical therapy can be identified. Key ingredients for success are preoperative evaluation and management and postoperative care by an interdisciplinary heart team. CONCLUSIONS: Given the discordance observed between trials, ongoing innovation in patient management, and potential expansion of indications for use, the evidence base must be expanded to optimize appropriate implementation of this complex therapy. This will require more complete capture of outcome data in real-world settings for all eligible candidates whether or not they receive this therapy. Inevitably, the indications for use of this therapy will expand, as will the devices and therapeutic approaches for this population, necessitating the study of comparative effectiveness through randomized trials or observational studies. Moreover, given the substantial variations in care delivery, conducting implementation research to delineate characteristics of the optimal care model would be of benefit.

Brener, M. I., P. Grayburn, J. Lindenfeld, D. Burkhoff, M. Liu, Z. Zhou, M. C. Alu, D. A. Medvedofsky, F. M. Asch, N. J. Weissman, J. Bax, W. Abraham, M. J. Mack, G. W. Stone and R. T. Hahn (2021). “Right Ventricular-Pulmonary Arterial Coupling in Patients With HF Secondary MR: Analysis From the COAPT Trial.” JACC Cardiovasc Interv 14(20): 2231-2242.

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OBJECTIVES: The aim of this study was to determine the prognostic impact of right ventricular (RV)-pulmonary arterial (PA) coupling in patients with heart failure (HF) with severe secondary mitral regurgitation (SMR) enrolled in the COAPT (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients With Functional Mitral Regurgitation) trial. BACKGROUND: RV contractile function and PA pressures influence outcomes in patients with SMR, but the impact of RV-PA coupling in patients randomized to transcatheter edge-to-edge repair (TEER) vs guideline-directed medical therapy (GDMT) is unknown. METHODS: RV-PA coupling was assessed by the ratio of RV free wall longitudinal strain derived from speckle-tracking echocardiography and noninvasively measured RV systolic pressure. Advanced RV-PA uncoupling was defined as RV free wall longitudinal strain/RV systolic pressure ≤0.5%/mm Hg. The primary endpoint was a composite of all-cause mortality or HF hospitalization at 24-month follow-up. RESULTS: A total of 372 patients underwent speckle-tracking echocardiography, and 70.2% had advanced RV-PA uncoupling. By multivariable analysis, advanced RV-PA uncoupling was strongly associated with an increased risk for the primary 24-month endpoint of death or HF hospitalization (HR: 1.87; 95% CI: 1.31-2.66; P = 0.0005). A similar association was present for all-cause mortality alone (HR: 2.57; 95% CI: 1.54-4.29; P = 0.0003). The impact of RV-PA uncoupling was consistent in patients randomized to TEER and GDMT alone. Compared with GDMT alone, the addition of TEER improved 2-year outcomes in patients with (48.0% vs 74.8%; HR: 0.51; 95% CI: 0.37-0.71) and those without (28.8% vs 47.8%; HR: 0.51; 95% CI: 0.27-0.97) advanced RV-PA uncoupling (P(interaction) = 0.98). CONCLUSIONS: In the COAPT trial, advanced RV dysfunction assessed by RV-PA uncoupling was a powerful predictor of 2-year adverse outcomes in patients with HF and SMR. (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients With Functional Mitral Regurgitation [The COAPT Trial]; NCT01626079).

Alam, A. (2021). “Effect of Near Monopoly in the Left Ventricular Assist Device Market.” Am J Cardiol Oct 24;S0002-9149(21)00957-7. [Epub ahead of print].

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These 2 devices were the most implanted LVADs in the world. However, on June 3, 2021, Medtronic announced that it would stop distribution of the HVAD, given the malfunctioning of the device’s start and stop mechanisms in addition to a high frequency of neurologic events. With HVADs no longer being implanted, will HM3 now monopolize the LVAD market? Herein a brief overview of LVADs that are within the horizon of our time.[No abstract; excerpt from article].

Fan, J., K. Hammonds, B. Izekor, C. Jones, P. McGrade, J. B. Michel and R. J. Widmer (2021). “Association of Maximum Troponin Levels With Diagnosis of Acute Myocardial Infarction and Elevated Risk of Mortality.” Ochsner J 21(3): 261-266.

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Background: Cardiac troponins I and T are highly sensitive and specific markers for acute myocardial infarction (AMI). However, a wide range of non-AMI conditions can also cause significant elevations in cardiac troponins. Given the deleterious impact of misdiagnosis of AMI, the ability to risk-stratify patients who present with an elevated troponin is paramount. We hypothesized that the maximum troponin level would be more predictive of mortality and the diagnosis of AMI than the initial troponin level or change in troponin level. Methods: Patient records from a 9-hospital system (n=30,173) in Texas were reviewed during a 24-month period in 2016-2017. Data collected for patients aged ≥40 years included International Classification of Diseases, Tenth Revision diagnoses, troponin I, demographic data (age, sex, smoking history, and chronic medical conditions), and death during hospitalization. We used logistic regression with the Firth penalized likelihood approach to determine the predictive ability of initial, maximum, and change in troponin level for mortality and the diagnosis of AMI. Results: Demographic characteristics of our cohort included a median age of 70 years, with 48.05% male and 51.95% female. The most common preexisting risk factor was hypertension in 78.81% of the cohort. Notable findings from the logistic regression include the predictive ability of maximum troponin on the odds of death by 0.7% for each unit of increase in troponin value. Also, the odds of AMI increased by 3.1% for each unit of increase in the maximum troponin value. Conclusion: Regardless of the level, a detectable amount of troponin in the serum results in a significantly elevated risk of mortality. Many patients with elevated troponin levels leave the hospital without a specific diagnosis, which can lead to poor outcomes because a detectable troponin does not represent a no-risk population. Our study demonstrates that maximum troponin level is a more sensitive and specific predictor of mortality than initial or change in troponin. Similarly, maximum troponin is the most predictive of AMI vs other causes of troponin elevation, likely because of the correlation between rising troponin levels and cardiomyocyte damage. Further studies are needed to correlate maximum troponin levels and clinical manifestations, which may be helpful in redefining AMI so that AMI can be distinguished more easily from non-AMI diagnoses.

Squiers, J. J. and J. M. DiMaio (2021). “SYNTAX Score II 2020: A Remake Worth the Price of Admission?” J Am Coll Cardiol 78(12): 1239-1241.

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The SYNTAX score has been widely applied in clinical trial design and clinical practice to objectively measure and stratify the anatomical complexity of coronary artery disease (CAD) (1). Calculation of the SYNTAX score to inform heart team decision-making for patients with multivessel CAD has also been recommended in the 2014 American guidelines and 2018 European guidelines. Defining the complexity of CAD by the SYNTAX score has proven useful as an independent predictor of long-term survival and major adverse cardiovascular events (MACE) in patients undergoing percutaneous coronary intervention (PCI) but not those undergoing coronary artery bypass grafting (CABG). Thus, the value of the SYNTAX score for treatment selection between CABG and PCI by the heart team is uncertain. [No abstract; excerpt from article].