Research Spotlight

Zile, M. R., E. O’Meara, B. Claggett, M. F. Prescott, S. D. Solomon, K. Swedberg, M. Packer, J. J. V. McMurray, V. Shi, M. Lefkowitz and J. Rouleau (2019). “Effects of Sacubitril/Valsartan on Biomarkers of Extracellular Matrix Regulation in Patients With HFrEF.” J Am Coll Cardiol 73(7): 795-806.

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BACKGROUND: Myocardial fibrosis is an important pathophysiological mechanism underlying the development of heart failure (HF). Given the biochemical targets of sacubitril/valsartan, we hypothesized that circulating biomarkers reflecting the mechanisms that determine extracellular matrix (ECM) homeostasis, including collagen synthesis, processing, and degradation, are altered by sacubitril/valsartan in comparison to enalapril. OBJECTIVES: The purpose of this study was to examine the effects of sacubitril/valsartan on biomarkers of ECM homeostasis and the association between the rate of primary composite outcome (cardiovascular death or HF hospitalization) and these biomarkers. METHODS: Biomarkers at baseline (n = 2,067) and both baseline and 8 months after randomization (n = 1,776) included aldosterone, soluble ST2 (sST2), tissue inhibitor of matrix metalloproteinase (TIMP)-1, matrix metalloproteinase (MMP)-2, MMP-9, Galectin-3 (Gal-3), N-terminal propeptide of collagen I (PINP), and N-terminal propeptide of collagen III (PIIINP). The effects of sacubitril/valsartan on biomarkers were compared with enalapril. Baseline biomarker values and changes from baseline to 8 months were related to primary outcome. RESULTS: At baseline, the profibrotic biomarkers aldosterone, sST2, TIMP-1, Gal-3, PINP, and PIIINP were higher, and biomarkers associated with collagen degradation, MMP-2 and -9, were lower than published referent control values. Eight months after randomization, aldosterone, sST2, TIMP-1, MMP-9, PINP, and PIIINP had decreased more in the sacubitril/valsartan than enalapril group. At baseline, higher values of sST-2, TIMP-1, and PIIINP were associated with higher primary outcome rates. Changes from baseline to 8 months in sST-2 and TIMP-1 were associated with change in outcomes. CONCLUSIONS: Biomarkers associated with profibrotic signaling are altered in HF with reduced ejection fraction, sacubitril/valsartan significantly decreased many of these biomarkers, and these biomarkers have important prognostic value. These findings suggest that sacubitril/valsartan may reduce profibrotic signaling, which may contribute to the improved outcomes. (This Study Will Evaluate the Efficacy and Safety of LCZ696 Compared to Enalapril on Morbidity and Mortality of Patients With Chronic Heart Failure [PARADIGM-HF]; NCT01035255).

Zaidat, O. O., N. H. Mueller-Kronast, A. E. Hassan, D. C. Haussen, A. P. Jadhav, M. T. Froehler, R. Jahan, M. Ali Aziz-Sultan, R. P. Klucznik, J. L. Saver, F. R. Hellinger, Jr., D. R. Yavagal, T. L. Yao, R. Gupta, C. O. Martin, H. Bozorgchami, R. Kaushal, R. G. Nogueira, R. H. Gandhi, E. C. Peterson, S. Dashti, C. A. Given, 2nd, B. P. Mehta, V. Deshmukh, S. Starkman, I. Linfante, S. H. McPherson, P. Kvamme, T. J. Grobelny, M. S. Hussain, I. Thacker, N. Vora, P. R. Chen, S. J. Monteith, R. D. Ecker, C. M. Schirmer, E. Sauvageau, A. B. Chebl, C. P. Derdeyn, L. Maidan, A. Badruddin, A. H. Siddiqui, T. M. Dumont, A. Alhajeri, M. A. Taqi, K. Asi, J. Carpenter, A. Boulos, G. Jindal, A. S. Puri, R. Chitale, E. M. Deshaies, D. Robinson, D. F. Kallmes, B. W. Baxter, M. Jumaa, P. Sunenshine, A. Majjhoo, J. D. English, S. Suzuki, R. D. Fessler, J. Delgado-Almandoz, J. C. Martin and D. S. Liebeskind (2019). “Impact of Balloon Guide Catheter Use on Clinical and Angiographic Outcomes in the STRATIS Stroke Thrombectomy Registry.” Stroke 50(3): 697-704.

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Background and Purpose- Mechanical thrombectomy has been shown to improve clinical outcomes in patients with acute ischemic stroke. However, the impact of balloon guide catheter (BGC) use is not well established. Methods- STRATIS (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke) was a prospective, multicenter study of patients with large vessel occlusion treated with the Solitaire stent retriever as first-line therapy. In this study, an independent core laboratory, blinded to the clinical outcomes, reviewed all procedures and angiographic data to classify procedural technique, target clot location, recanalization after each pass, and determine the number of stent retriever passes. The primary clinical end point was functional independence (modified Rankin Scale, 0-2) at 3 months as determined on-site, and the angiographic end point was first-pass effect (FPE) success rate from a single device attempt (modified Thrombolysis in Cerebral Infarction, >/=2c) as determined by a core laboratory. Achieving modified FPE (modified Thrombolysis in Cerebral Infarction, >/=2b) was also assessed. Comparisons of clinical outcomes were made between groups and adjusted for baseline and procedural characteristics. All participating centers received institutional review board approval from their respective institutions. Results- Adjunctive technique groups included BGC (n=445), distal access catheter (n=238), and conventional guide catheter (n=62). The BGC group had a higher rate of FPE following first pass (212/443 [48%]) versus conventional guide catheter (16/62 [26%]; P=0.001) and distal access catheter (83/235 [35%]; P=0.002). Similarly, the BGC group had a higher rate of modified FPE (294/443 [66%]) versus conventional guide catheter (26/62 [42%]; P<0.001) and distal access catheter (129/234 [55%]; P=0.003). The BGC group achieved the highest rate of functional independence (253/415 [61%]) versus conventional guide catheter (23/55 [42%]; P=0.007) and distal access catheter (113/218 [52%]; P=0.027). Final revascularization and mortality rates did not differ across the groups. Conclusions- BGC use was an independent predictor of FPE, modified FPE, and functional independence, suggesting that its routine use may improve the rates of early revascularization success and good clinical outcomes. Clinical Trial Registration- URL: https://www.clinicaltrials.gov . Unique identifier: NCT02239640.

Ward, M. A., T. Hassan, J. S. Burdick and S. G. Leeds (2019). “Endoscopic vacuum assisted wound closure (EVAC) device to treat esophageal and gastric leaks: assessing time to proficiency and cost.” Surg Endosc Feb 11. [Epub ahead of print].

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BACKGROUND: Endoluminal vacuum therapy (EVAC) is an emerging procedure used to treat anastomotic leaks and/or perforations that would otherwise require surgery. The aim of this study was to determine time to proficiency in EVAC and the cost effectiveness of the procedure. METHODS: We retrospectively reviewed a prospectively maintained IRB approved database for all patients undergoing EVAC after esophageal and gastric complications between October 2013 and December 2017. Proficiency was determined by obtaining predicted estimates and analyzing the point at which average procedure time plateaued based on case volume. Total cost was calculated based on supplies and location where the procedure was performed. RESULTS: There were 50 patients (17 males, 33 female), with a mean age of 52.1 years. EVAC was placed in 23 (46%) patients with esophageal injuries and 28 (56%) with gastric injuries. Two advanced endoscopists performed all EVAC procedures in this study (1 surgeon, 1 gastroenterologist). The average procedure time for all patients was 43.5 min and the average wheel in/wheel out time for all patients was 75.6 min. Analysis of the trend based on average procedure times for EVAC revealed that proficiency was obtained after 10 cases. Total cost of the procedure is significantly lower in the GI lab compared to the operating room ($4528 vs. $11889). The majority of EVAC were performed in the GI lab (62%) compared to the operating room (38%). CONCLUSION: Successful outcomes in managing anastomotic leaks or intestinal perforations non-operatively has led to an increased interest in EVAC. For advanced endoscopists, time to proficiency is approximately 10 cases. Performing the procedure in the GI lab has a 2.5 reduction in total cost compared to the operating room.

Walters, D. C., E. Arning, T. Bottiglieri, E. E. W. Jansen, G. S. Salomons, M. N. Brown, M. A. Schmidt, G. R. Ainslie, J. B. Roullet and K. M. Gibson (2019). “Metabolomic analyses of vigabatrin (VGB)-Treated mice: GABA-transaminase inhibition significantly alters amino acid profiles in murine neural and non-neural tissues.” Neurochem Int.

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The anticonvulsant vigabatrin (VGB; Sabril(R)) irreversibly inhibits GABA transaminase to increase neural GABA, yet its mechanism of retinal toxicity remains unclear. VGB is suggested to alter several amino acids, including homocarnosine, beta-alanine, ornithine, glycine, taurine, and 2-aminoadipic acid (AADA), the latter a homologue of glutamic acid. Here, we evaluate the effect of VGB on amino acid concentrations in mice, employing a continuous VGB infusion (subcutaneously implanted osmotic minipumps), dose-escalation paradigm (35-140mg/kg/d, 12 days), and amino acid quantitation in eye, visual and prefrontal cortex, total brain, liver and plasma. We hypothesized that continuous VGB dosing would reveal numerous hitherto undescribed amino acid disturbances. Consistent amino acid elevations across tissues included GABA, beta-alanine, carnosine, ornithine and AADA, as well as neuroactive aspartic and glutamic acids, serine and glycine. Maximal increase of AADA in eye occurred at 35mg/kg/d (41+/-2nmol/g (n=21, vehicle) to 60+/-8.5 (n=8)), and at 70mg/kd/d for brain (97+/-6 (n=21) to 145+/-6 (n=6)), visual cortex (128+/-6 to 215+/-19) and prefrontal cortex (124+/-11 to 200+/-13; mean+/-SEM; p<0.05), the first demonstration of tissue AADA accumulation with VGB in mammal. VGB effects on basic amino acids, including guanidino-species, suggested the capacity of VGB to alter urea cycle function and nitrogen disposal. The known toxicity of AADA in retinal glial cells highlights new avenues for assessing VGB retinal toxicity and other off-target effects.

Vardeny, O., B. Claggett, J. Kachadourian, A. S. Desai, M. Packer, J. Rouleau, M. R. Zile, K. Swedberg, M. Lefkowitz, V. Shi, J. J. V. McMurray and S. D. Solomon (2019). “Reduced loop diuretic use in patients taking sacubitril/valsartan compared with enalapril: the PARADIGM-HF trial.” Eur J Heart Fail.

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AIMS: To assess differences in diuretic dose requirements in patients treated with sacubitril/valsartan compared with enalapril in the Prospective comparison of ARNI with ACEI to Determine Impact on Global Mortality and morbidity in Heart Failure (PARADIGM-HF) trial. METHODS AND RESULTS: Overall, 8399 patients with New York Heart Association class II-IV heart failure and reduced LVEF were randomized to sacubitril/valsartan 200 mg bid or enalapril 10 mg twice daily. Loop diuretic doses were assessed at baseline, 6, 12, and 24 months, and furosemide dose equivalents were calculated via multiplication factors (2x for torsemide and 40x for bumetanide). Percentages of participants with reductions or increases in loop diuretic dose were determined. At baseline, 80.8% of participants were taking any diuretics (n = 6290 for loop diuretics, n = 496 for other diuretics); of those, recorded dosage data for loop diuretics were available on 5487 participants. Mean baseline furosemide equivalent doses were 48.2 mg for sacubitril/valsartan and 49.6 mg for enalapril (P = 0.25). Patients treated with sacubitril/valsartan were more likely to reduce diuretic dose and less likely to increase diuretic dose relative to those randomized to enalapril at 6, 12, 24 months post-randomization, with an overall decreased diuretic use of 2.0% (P = 0.02), 4.1% (P < 0.001), and 6.1% (P < 0.001) at 6, 12, and 24 months, respectively, with similar findings in an on-treatment analysis. CONCLUSION: Treatment with sacubitril/valsartan was associated with more loop diuretic dose reductions and fewer dose increases compared with enalapril, suggesting that treatment with sacubitril/valsartan may reduce the requirement for loop diuretics relative to enalapril in patients with heart failure with reduced ejection fraction.