Milton Packer M.D.

Damman, K., M. Gori, B. Claggett, P. S. Jhund, M. Senni, M. P. Lefkowitz, M. F. Prescott, V. C. Shi, J. L. Rouleau, K. Swedberg, M. R. Zile, M. Packer, A. S. Desai, S. D. Solomon and J. J. V. McMurray (2018). “Renal Effects and Associated Outcomes During Angiotensin-Neprilysin Inhibition in Heart Failure.” JACC Heart Fail. Apr 11. [Epub ahead of print].

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OBJECTIVES: The purpose of this study was to evaluate the renal effects of sacubitril/valsartan in patients with heart failure and reduced ejection fraction. BACKGROUND: Renal function is frequently impaired in patients with heart failure with reduced ejection fraction and may deteriorate further after blockade of the renin-angiotensin system. METHODS: In the PARADIGM-HF (Prospective Comparison of ARNI with ACE inhibition to Determine Impact on Global Mortality and Morbidity in Heart Failure) trial, 8,399 patients with heart failure with reduced ejection fraction were randomized to treatment with sacubitril/valsartan or enalapril. The estimated glomerular filtration rate (eGFR) was available for all patients, and the urinary albumin/creatinine ratio (UACR) was available in 1872 patients, at screening, randomization, and at fixed time intervals during follow-up. We evaluated the effect of study treatment on change in eGFR and UACR, and on renal and cardiovascular outcomes, according to eGFR and UACR. RESULTS: At screening, the eGFR was 70 +/- 20 ml/min/1.73 m(2) and 2,745 patients (33%) had chronic kidney disease; the median UACR was 1.0 mg/mmol (interquartile range: 0.4 to 3.2 mg/mmol) and 24% had an increased UACR. The decrease in eGFR during follow-up was less with sacubitril/valsartan compared with enalapril (-1.61 ml/min/1.73 m(2)/year; [95% confidence interval: -1.77 to -1.44 ml/min/1.73 m(2)/year] vs. -2.04 ml/min/1.73 m(2)/year [95% CI: -2.21 to -1.88 ml/min/1.73 m(2)/year ]; p < 0.001) despite a greater increase in UACR with sacubitril/valsartan than with enalapril (1.20 mg/mmol [95% CI: 1.04 to 1.36 mg/mmol] vs. 0.90 mg/mmol [95% CI: 0.77 to 1.03 mg/mmol]; p < 0.001). The effect of sacubitril/valsartan on cardiovascular death or heart failure hospitalization was not modified by eGFR, UACR (p interaction = 0.70 and 0.34, respectively), or by change in UACR (p interaction = 0.38). CONCLUSIONS: Compared with enalapril, sacubitril/valsartan led to a slower rate of decrease in the eGFR and improved cardiovascular outcomes, even in patients with chronic kidney disease, despite causing a modest increase in UACR.

Packer, M. and D. W. Kitzman (2018). “Obesity-Related Heart Failure With a Preserved Ejection Fraction: The Mechanistic Rationale for Combining Inhibitors of Aldosterone, Neprilysin, and Sodium-Glucose Cotransporter-2.” JACC Heart Fail Mar 7. [Epub ahead of print].

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Obesity-related heart failure with a preserved ejection fraction (HFpEF) is an important phenotype prevalent in the community, especially in people with metabolic disorders (e.g., dyslipidemia, diabetes). These individuals exhibit a marked expansion of plasma volume, but ventricular distensibility is limited, most likely as a result of cardiac microvascular rarefaction acting in concert with myocardial and pericardial fibrosis. Consequently, the increase in plasma volume causes a disproportionate increase in cardiac filling pressures, leading to heart failure, even though systolic ejection is not impaired. The features of this syndrome appear to be related (in part) to the overproduction of adipocyte-derived cell-signaling molecules, including aldosterone and neprilysin. The resulting sodium retention and plasma volume expansion is exacerbated by their mutual actions to promote cardiac and systemic inflammation and fibrosis. Inhibitors of aldosterone, neprilysin and the sodium-glucose transporter-2 (SGLT2) can ameliorate the plasma volume expansion and pro-inflammatory and profibrotic pathways, potentially opposing the action of diverse adipocytokines. All 3 classes of drugs can reduce the quantity of visceral adipose tissue and ameliorate its abnormal biological properties. This mechanistic framework is supported by the results of large-scale randomized trials with mineralocorticoid receptor antagonists and SGLT2 inhibitors and is being further tested in an ongoing large-scale trial of neprilysin inhibition. The promise of using mineralocorticoid receptor antagonists, neprilysin inhibitors, and SGLT2 inhibitors (alone or in combination) in the management of obesity-related HFpEF suggests that physicians might finally have a phenotype of HFpEF that they can understand and treat.

Packer, M. (2018). “Role of the sodium-hydrogen exchanger in mediating the renal effects of drugs commonly used in the treatment of type 2 diabetes.” Diabetes Obes Metab 20(4): 800-811.

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Diabetes is characterized by increased activity of the sodium-hydrogen exchanger (NHE) in the glomerulus and renal tubules, which contributes importantly to the development of nephropathy. Despite the established role played by the exchanger in experimental studies, it has not been specifically targeted by those seeking to develop novel pharmacological treatments for diabetes. This review demonstrates that many existing drugs that are commonly prescribed to patients with diabetes act on the NHE1 and NHE3 isoforms in the kidney. This action may explain their effects on sodium excretion, albuminuria and the progressive decline of glomerular function in clinical trials; these responses cannot be readily explained by the influence of these drugs on blood glucose. Agents that may affect the kidney in diabetes by virtue of an action on NHE include: (1) insulin and insulin sensitizers; (2) incretin-based agents; (3) sodium-glucose cotransporter 2 inhibitors; (4) antagonists of the renin-angiotensin system (angiotensin converting-enzyme inhibitors, angiotensin receptor blockers and angiotensin receptor neprilysin inhibitors); and (5) inhibitors of aldosterone action and cholesterol synthesis (spironolactone, amiloride and statins). The renal effects of each of these drug classes in patients with type 2 diabetes may be related to a single shared biological mechanism.

Packer, M. (2018). “Potential mechanisms underlying differences in the effect of incretin-based antidiabetic drugs on the risk of major atherosclerotic ischemic events.” J Diabetes Complications Mar 24. [Epub ahead of print].

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Among the incretin-based antidiabetic drugs, there is an understandable preference for the use of DPP-4 inhibitors over long-acting GLP-1 analogs, because the former are orally effective and do not require daily subcutaneous injections. However, physicians should not assume that incretin-based drugs have similar effects on the risk of atherosclerotic ischemic events simply because they share a common ability to enhance signaling through the GLP-1 receptor. Unlike DPP-4 inhibitors, long-acting GLP-1 analogs can reduce the risk of major adverse ischemic cardiovascular events, even when administered for only a few years. This benefit cannot be explained by their effects on blood glucose and cannot be replicated by sitagliptin and saxagliptin, possibly because DPP-4 inhibitors simultaneously enhance the plaque-destabilizing effects of endogenous proinflammatory chemokines. (Excerpt from text, p. 2; no abstract available.)

Packer, M. (2018). “Inferential characterization of the dose-response relationships of neurohormonal antagonists in chronic heart failure: A novel approach based on large-scale trials with active comparators.” Int J Cardiol. Mar 11. [Epub ahead of print].

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BACKGROUND: Current guidelines for the treatment of heart failure strongly recommend the use of inhibitors of the renin-angiotensin system and sympathetic nervous system in all patients with a reduced ejection fraction who can tolerate these drugs. Yet, there is no consensus about the efficacy of low doses of these drugs or the likely shape of the dose-response relationship for these agents. METHODS: Inferences were made by examining the effects of drugs in placebo-controlled trials before the protocol-specified opportunity for uptitration and by reassessing the results of large-scale trials with active comparators that inadvertently produced different intensities of neurohormonal blockade. RESULTS: In the case of inhibitors of the renin-angiotensin system, low starting doses appear to be effective in many patients, and 3-5 fold increases in dose do not have a mortality advantage over low doses. By contrast, in the case of beta-adrenergic blockers, although low starting doses appear effective in improving outcomes, achievement of target doses may yield substantial incremental mortality benefits, even such doses are accompanied by only small additional decreases in heart rate. CONCLUSION: When treating patients with heart failure to reduce mortality, the totality of evidence supports a relatively flat dose-response relationship for inhibitors of the renin-angiotensin system but a steep dose-response relationship for beta-adrenergic receptor blockers.