Research Spotlight

Arnold, S. V., K. M. Chinnakondepalli, J. A. Spertus, E. A. Magnuson, S. J. Baron, S. Kar, D. S. Lim, J. M. Mishell, W. T. Abraham, J. A. Lindenfeld, M. J. Mack, G. W. Stone and D. J. Cohen (2019). “Health Status After Transcatheter Mitral-Valve Repair in Heart Failure and Secondary Mitral Regurgitation: COAPT Trial.” J Am Coll Cardiol 73(17): 2123-2132.

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BACKGROUND: In the COAPT (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional Mitral Regurgitation) trial, transcatheter mitral valve repair (TMVr) led to reduced heart failure (HF) hospitalizations and improved survival in patients with symptomatic HF and 3+ to 4+ secondary mitral regurgitation (MR) on maximally-tolerated medical therapy. Given the advanced age and comorbidities of these patients, improvement in health status is also an important treatment goal. OBJECTIVES: The purpose of this study was to understand the health status outcomes of patients with HF and 3+ to 4+ secondary MR treated with TMVr versus standard care. METHODS: The COAPT trial randomized patients with HF and 3+ to 4+ secondary MR to TMVr (n = 302) or standard care (n = 312). Health status was assessed at baseline and at 1, 6, 12, and 24 months with the Kansas City Cardiomyopathy Questionnaire (KCCQ) and the SF-36 health status survey. The primary health status endpoint was the KCCQ overall summary score (KCCQ-OS; range 0 to 100; higher = better; minimum clinically important difference = 5 points). RESULTS: At baseline, patients had substantially impaired health status (mean KCCQ-OS 52.4 +/- 23.0). While health status was unchanged over time in the standard care arm, patients randomized to TMVr demonstrated substantial improvement in the KCCQ-OS at 1 month (mean between-group difference 15.9 points; 95% confidence interval [CI]: 12.3 to 19.5 points), with only slight attenuation of this benefit through 24 months (mean between-group difference 12.8 points; 95% CI: 7.5 to 18.2 points). At 24 months, 36.4% of TMVr patients were alive with a moderately large (>/=10-point) improvement versus 16.6% of standard care patients (p < 0.001), for a number needed to treat of 5.1 patients (95% CI: 3.6 to 8.7 patients). TMVr patients also reported better generic health status at each timepoint (24-month mean difference in SF-36 summary scores: physical 3.6 points; 95% CI: 1.4 to 5.8 points; mental 3.6 points; 95% CI: 0.8 to 6.4 points). CONCLUSIONS: Among patients with symptomatic HF and 3+ to 4+ secondary MR receiving maximally-tolerated medical therapy, edge-to-edge TMVr resulted in substantial early and sustained health status improvement compared with medical therapy alone. (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients With Functional Mitral Regurgitation [The COAPT Trial] [COAPT]; NCT01626079).

Alonso-Hearn, M., G. Magombedze, N. Abendano, M. Landin and R. A. Juste (2019). “Deciphering the virulence of Mycobacterium avium subsp. paratuberculosis isolates in animal macrophages using mathematical models.” J Theor Biol 468: 82-91.

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Understanding why pathogenic Mycobacterium avium subsp. paratuberculosis (Map) isolates cause disparate disease outcomes with differing magnitudes of severity is important in designing and implementing new control strategies. We applied a suite of mathematical models: i) general linear, ii) and neurofuzzy logic, to explain how the host of origin of several Map isolates, Map genotype, host, macrophage-based in vitro model and time post-infection contributed to the infection. A logistic growth ordinary differential equation (ODE) model was applied to estimate within macrophage growth rates for the different Map isolates. The models revealed different susceptibilities of bovine and ovine macrophages to Map infection and confirmed distinct virulence profiles for the isolates, judged by their ability to grow within macrophages. Ovine macrophages were able to internalize Map isolates more efficiently than bovine macrophages. While bovine macrophages were able to internalize Map isolates from cattle with more efficiency, ovine macrophages were more efficient in internalizing ovine isolates. Overall, Map isolates from goat and sheep grew minimally within macrophages or did not grow but were able to persist by maintaining its initial population. In contrast, the ability of the bovine isolates and the non-domesticated animal isolates to grow to higher CFU numbers within macrophages suggests that these isolates are more virulent than the sheep and goat isolates, or that these isolates are better adapted to infect domestic ruminants. Overall, our study confirms the different virulence levels for the Map isolates and susceptibility profiles of host macrophages, which is crucial in increasing our understanding of Map infection.

Ahmad, F. S., M. A. Kallen, K. E. Schifferdecker, K. L. Carluzzo, S. E. Yount, J. M. Gelow, P. A. McCullough, S. E. Kimmel, E. S. Fisher and D. Cella (2019). “Development and Initial Validation of the PROMIS(R)-Plus-HF Profile Measure.” Circ Heart Fail 12(6): e005751.

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Background Bringing together generic and heart failure (HF)-specific items in a publicly available, patient-reported outcome measure may facilitate routine health status assessment for improving clinical care and shared decision-making, assessing quality of care, evaluating new interventions, and comparing groups with different conditions. Methods and Results We performed a mixed-methods study to develop and validate the PROMIS(R)-Plus-HF (Patient-Reported Outcomes Measurement Information System(R)-Plus-Heart Failure) profile measure-a HF-specific instrument based on the generic PROMIS. We conducted 8 focus groups with 61 patients with HF and phone interviews with 10 HF clinicians. The measure was developed via an iterative process of reviewing existing PROMIS items and developing and testing new HF items. In a 600-patient sample, we estimated reliability (internal consistency; test-retest, with n=100 participants). We conducted validity analyses using Pearson r and Spearman rho correlations with Kansas City Cardiomyopathy Questionnaire subscores. In a longitudinal sample, we performed responsiveness testing (paired t tests) with 75 patients with HF receiving interventions with expected health status improvement. The PROMIS-Plus-HF measure comprises 86 items (64 existing; 22 new) across 18 domains. Internal consistency reliability (Cronbach alpha) coefficients ranged from 0.52 to 0.96, with alpha>/=0.70 in 12 of 17 domains. Test-retest intraclass correlation coefficients were >/=0.90. Correlations with Kansas City Cardiomyopathy Questionnaire subscores supported expected convergent (r/rho>0.60) and divergent validity (r/rho<0.30). In the longitudinal sample, 10 of 18 domains had improved (P<0.05) scores from baseline to follow-up. Conclusions The PROMIS-Plus-HF profile measure-a complete assessment of physical, mental, and social health-exhibited good psychometric characteristics and may facilitate patient-centered care and research. Subsets of domains and items can be used depending on the clinical or research purpose.

Abu Ahmad, N., M. Raizman, N. Weizmann, B. Wasek, E. Arning, T. Bottiglieri, O. Tirosh and A. M. Troen (2019). “Betaine attenuates pathology by stimulating lipid oxidation in liver and regulating phospholipid metabolism in brain of methionine-choline-deficient rats.” FASEB Journal May 23. [Epub ahead of print].

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Methyl-donor deficiency is a risk factor for neurodegenerative diseases. Dietary deficiency of the methyl-donors methionine and choline [methionine-choline-deficient (MCD) diet] is a well-established model of nonalcoholic steatohepatitis (NASH), yet brain metabolism has not been studied in this model. We hypothesized that supplemental betaine would protect both the liver and brain in this model and that any benefit to the brain would be due to improved liver metabolism because betaine is a methyl-donor in liver methylation but is not metabolically active in the brain. We fed male Sprague-Dawley rats a control diet, MCD diet, or betaine-supplemented MCD (MCD+B) diet for 8 wk and collected blood and tissue. As expected, betaine prevented MCD diet-induced NASH. However, contrary to our prediction, it did not appear to do so by stimulating methylation; the MCD+B diet worsened hyperhomocysteinemia and depressed liver methylation potential 8-fold compared with the MCD diet. Instead, it significantly increased the expression of genes involved in beta-oxidation: fibroblast growth factor 21 and peroxisome proliferator-activated receptor alpha. In contrast to that of the liver, brain methylation potential was unaffected by diet. Nevertheless, several phospholipid (PL) subclasses involved in stabilizing brain membranes were decreased by the MCD diet, and these improved modestly with betaine. The protective effect of betaine is likely due to the stimulation of beta-oxidation in liver and the effects on PL metabolism in brain.-Abu Ahmad, N., Raizman, M., Weizmann, N., Wasek, B., Arning, E., Bottiglieri, T., Tirosh, O., Troen, A. M. Betaine attenuates pathology by stimulating lipid oxidation in liver and regulating phospholipid metabolism in brain of methionine-choline-deficient rats.

Mack, M. J., M. B. Leon, V. H. Thourani, R. Makkar, S. K. Kodali, M. Russo, S. R. Kapadia, S. C. Malaisrie, D. J. Cohen, P. Pibarot, J. Leipsic, R. T. Hahn, P. Blanke, M. R. Williams, J. M. McCabe, D. L. Brown, V. Babaliaros, S. Goldman, W. Y. Szeto, P. Genereux, A. Pershad, S. J. Pocock, M. C. Alu, J. G. Webb and C. R. Smith (2019). “Transcatheter Aortic-Valve Replacement with a Balloon-Expandable Valve in Low-Risk Patients.” New England Journal of Medicine 380(18): 1695-1705.

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BACKGROUND: Among patients with aortic stenosis who are at intermediate or high risk for death with surgery, major outcomes are similar with transcatheter aortic-valve replacement (TAVR) and surgical aortic-valve replacement. There is insufficient evidence regarding the comparison of the two procedures in patients who are at low risk. METHODS: We randomly assigned patients with severe aortic stenosis and low surgical risk to undergo either TAVR with transfemoral placement of a balloon-expandable valve or surgery. The primary end point was a composite of death, stroke, or rehospitalization at 1 year. Both noninferiority testing (with a prespecified margin of 6 percentage points) and superiority testing were performed in the as-treated population. RESULTS: At 71 centers, 1000 patients underwent randomization. The mean age of the patients was 73 years, and the mean Society of Thoracic Surgeons risk score was 1.9% (with scores ranging from 0 to 100% and higher scores indicating a greater risk of death within 30 days after the procedure). The Kaplan-Meier estimate of the rate of the primary composite end point at 1 year was significantly lower in the TAVR group than in the surgery group (8.5% vs. 15.1%; absolute difference, -6.6 percentage points; 95% confidence interval [CI], -10.8 to -2.5; P<0.001 for noninferiority; hazard ratio, 0.54; 95% CI, 0.37 to 0.79; P = 0.001 for superiority). At 30 days, TAVR resulted in a lower rate of stroke than surgery (P = 0.02) and in lower rates of death or stroke (P = 0.01) and new-onset atrial fibrillation (P<0.001). TAVR also resulted in a shorter index hospitalization than surgery (P<0.001) and in a lower risk of a poor treatment outcome (death or a low Kansas City Cardiomyopathy Questionnaire score) at 30 days (P<0.001). There were no significant between-group differences in major vascular complications, new permanent pacemaker insertions, or moderate or severe paravalvular regurgitation. CONCLUSIONS: Among patients with severe aortic stenosis who were at low surgical risk, the rate of the composite of death, stroke, or rehospitalization at 1 year was significantly lower with TAVR than with surgery. (Funded by Edwards Lifesciences; PARTNER 3 ClinicalTrials.gov number, NCT02675114.).