Cardiology

Solomon, S. D., J. J. V. McMurray, I. S. Anand, J. Ge, C. S. P. Lam, A. P. Maggioni, F. Martinez, M. Packer . . . and M. P. Lefkowitz (2019). “Angiotensin-Neprilysin Inhibition in Heart Failure with Preserved Ejection Fraction.” New England Journal of Medicine. Sep 1. [Epub ahead of print].

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BACKGROUND: The angiotensin receptor-neprilysin inhibitor sacubitril-valsartan led to a reduced risk of hospitalization for heart failure or death from cardiovascular causes among patients with heart failure and reduced ejection fraction. The effect of angiotensin receptor-neprilysin inhibition in patients with heart failure with preserved ejection fraction is unclear. METHODS: We randomly assigned 4822 patients with New York Heart Association (NYHA) class II to IV heart failure, ejection fraction of 45% or higher, elevated level of natriuretic peptides, and structural heart disease to receive sacubitril-valsartan (target dose, 97 mg of sacubitril with 103 mg of valsartan twice daily) or valsartan (target dose, 160 mg twice daily). The primary outcome was a composite of total hospitalizations for heart failure and death from cardiovascular causes. Primary outcome components, secondary outcomes (including NYHA class change, worsening renal function, and change in Kansas City Cardiomyopathy Questionnaire [KCCQ] clinical summary score [scale, 0 to 100, with higher scores indicating fewer symptoms and physical limitations]), and safety were also assessed. RESULTS: There were 894 primary events in 526 patients in the sacubitril-valsartan group and 1009 primary events in 557 patients in the valsartan group (rate ratio, 0.87; 95% confidence interval [CI], 0.75 to 1.01; P = 0.06). The incidence of death from cardiovascular causes was 8.5% in the sacubitril-valsartan group and 8.9% in the valsartan group (hazard ratio, 0.95; 95% CI, 0.79 to 1.16); there were 690 and 797 total hospitalizations for heart failure, respectively (rate ratio, 0.85; 95% CI, 0.72 to 1.00). NYHA class improved in 15.0% of the patients in the sacubitril-valsartan group and in 12.6% of those in the valsartan group (odds ratio, 1.45; 95% CI, 1.13 to 1.86); renal function worsened in 1.4% and 2.7%, respectively (hazard ratio, 0.50; 95% CI, 0.33 to 0.77). The mean change in the KCCQ clinical summary score at 8 months was 1.0 point (95% CI, 0.0 to 2.1) higher in the sacubitril-valsartan group. Patients in the sacubitril-valsartan group had a higher incidence of hypotension and angioedema and a lower incidence of hyperkalemia. Among 12 prespecified subgroups, there was suggestion of heterogeneity with possible benefit with sacubitril-valsartan in patients with lower ejection fraction and in women. CONCLUSIONS: Sacubitril-valsartan did not result in a significantly lower rate of total hospitalizations for heart failure and death from cardiovascular causes among patients with heart failure and an ejection fraction of 45% or higher. (Funded by Novartis; PARAGON-HF ClinicalTrials.gov number, NCT01920711.).

Mack, M. J. and M. B. Leon (2019). “Transcatheter Aortic-Valve Replacement in Low-Risk Patients. Reply.” New England Journal of Medicine 381(7): 684-685.

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Kaul’s major concern is that there were fewer primary end-point events in the Placement of Aortic Transcatheter Valves (PARTNER) 3 trial than in earlier trials. He states that the inclusion of rehospitalization in the composite primary end point led it to become the main driver for the superiority of TAVR and also introduced a bias against surgery owing to the number of concomitant procedures performed in the surgical group. In PARTNER 3, the primary end point was specifically chosen to account for the lower event rate expected in low-risk patients and was powered on the basis of anticipated event rates from previous PARTNER trials. The sample size assumed a composite end-point event rate of 16.6% in the surgery group and 14.6% in the TAVR group. In fact, the primary event rates were 15.1% and 8.5%, respectively, and all components of the composite end point directionally favored TAVR. Rehospitalization was included because we believe it is a meaningful adverse outcome in low-risk patients, and it has been used as the sole primary end point in other recent trials. The higher rate of concomitant procedures in surgery (26.4% vs. 7.9%), mentioned both by Kaul and by Perella and Anwar, is a reflection of real-world surgical practice. The heart team at each site concluded before randomization that either approach, surgery or TAVR, would yield the best possible outcome. Since those patients who had a concomitant procedure did not have a higher rate of primary end-point events, there was no bias against surgery. Data available at the 10-year follow-up should give further insight into the risks and benefits of each approach, especially among patients who underwent concomitant coronary revascularization. Baldetti et al. noted a higher incidence of new-onset LBBB among patients who underwent TAVR, which suggests the possibility of the unfavorable prognostic effect of mechanical dyssynchrony. We agree and have recently published an analysis of patients in the earlier, higher-risk trials that shows worse left ventricular systolic function and more adverse clinical outcomes in patients with new LBBB. Precisely for these reasons, all patients will be followed with clinical, echocardiographic, and electrocardiographic assessment annually for 10 years. Finally, Savas et al. express concern that the higher rate of mild paravalvular leak with TAVR may lead to increased late mortality, citing data from a PARTNER trial involving high-risk patients. Although we share their concern, subsequent analyses of intermediate-risk patients have not shown an increase in mortality with mild paravalvular regurgitation.4 Nonetheless, all patients will be carefully followed for 10 years to address this concern. (Authors’ response to several commentaries on their previously published studies: Mack MJ, Leon MB, Thourani VH, et al. Transcatheter aortic-valve replacement with a balloon-expandable valve in low-risk patients. N Engl J Med 2019;380:1695-1705 and Leon MB, Smith CR, Mack MJ, et al. Transcatheter or surgical aortic-valve replacement in intermediate-risk patients. N Engl J Med 2016;374:1609-1620.)

Rangaswami, J., S. Bangalore, B. Kaplan, K. A. Birdwell, A. C. Wiseman, P. A. McCullough and D. M. Dadhania (2019). “Cardiovascular disease care fragmentation in kidney transplantation: a call for action.” Kidney Int 96(3): 568-571.

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Kidney transplantation (KT) is the treatment of choice for end-stage kidney disease, offering the highest survival benefit among all the different renal replacement therapies. Long-term renal allograft and patient survival have shown substantial improvements over time: however, death with a functioning allograft remains the leading cause of late allograft loss, with cardiovascular disease (CVD)–related deaths representing a major cause of mortality. Although recipients of KT have a lower risk of CVD as compared with the 10- to 20-fold increased risk in patients on dialysis, their risk of CVD is substantially higher than that in the general population3 (Figure 1). The transplantation milieu represents the confluence of several traditional and nontraditional cardiovascular risk factors intrinsic to the backdrop of chronic kidney disease (CKD). The entry point of a patient with advanced CKD into transplantation juxtaposes several patient- and donor-related cardiovascular risk factors including preexisting diabetes and hypertension, dialysis vintage, chronic inflammation, allograft quality, donor age, and donor vascular disease. Several post-transplant risk factors are superimposed on this background, such as the chronic effects of immunosuppression with calcineurin inhibitors and steroids, episodes of allograft rejection, new-onset diabetes post-transplantation, and left ventricular hypertrophy. Reduction in CVD-related morbidity and mortality after KT poses challenges across several interfaces: the pre–kidney transplant cardiovascular evaluation, the period of active transplant listing, and post-transplant CVD care. According to the United States Renal Data System 2017 annual report, 18,021 kidney transplant procedures were performed in the United States in 2015, out of the 83,978 wait-listed candidates on maintenance dialysis alone, with a steady increase in the cumulative number of recipients living with a functioning kidney transplant.3 This mandates the need for a coordinated effort across these interfaces to optimize long-term patient and allograft outcomes. On behalf of the Cardiovascular Work Group of the Kidney Pancreas Community of Practice of the American Society of Transplantation, we summarize key factors that may contribute to CVD care fragmentation in KT and offer suggestions for optimizing CVD care delivery in this high-risk population. (Excerpt from text, p. 568-569; no abstract available.)

Packer, M. (2019). “What causes sudden death in patients with chronic heart failure and a reduced ejection fraction?” Eur Heart J Aug 7. [Epub ahead of print].

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Sudden death characterizes the mode of demise in 30-50% of patients with chronic heart failure and a reduced ejection fraction. Occasionally, these events have an identifiable pathophysiological trigger, e.g. myocardial infarction, catecholamine surges, or electrolyte imbalances, but in most circumstances, there is no acute precipitating mechanism. Instead, adverse left ventricular remodelling and fibrosis creates an exceptionally fragile and highly vulnerable substrate, which can be characterized using the model developed in theoretical physics of ‘self-organizing criticality’. This framework has been applied to describe the genesis of avalanches, nodes of traffic congestion unrelated to an accident, the abrupt system-wide failure of electrical grids, and the initiation of cancer and neurodegenerative diseases. Self-organizing criticality within the ventricular myocardium relies on complex adaptations to progressive stress and stretch, which evolve inevitably to an abrupt end (termed ‘cascading failure’), even though the rate of deterioration of the underlying disease process has not changed. The result is acute circulatory collapse (i.e. sudden death) in the absence of an identifiable triggering event. Cascading failure in a severely remodelled or fibrotic heart can become manifest electrically as a first-time ventricular tachyarrhythmia that is responsive to the shock delivered by an implantable cardioverter-defibrillator (ICD). Alternatively, it may present as an acute mechanical failure, which is manifest as (i) asystole, bradyarrhythmia, or electromechanical dissociation; or (ii) incessant ventricular fibrillation that persists despite repetitive ICD discharges; in both instances, the sudden deaths cannot be prevented by an ICD. This conceptual framework explains why anti-remodelling and antifibrotic interventions (i.e. neurohormonal antagonists and cardiac resynchronization) reduce the risk of sudden death in patients with heart failure in the absence of an ICD and provide incremental benefits in those with an ICD. The adoption of anti-remodelling and antifibrotic treatments may explain why the incidence of sudden death in clinical trials of heart failure has declined dramatically over the past 10-15 years, independent of the use of ICDs.

Packer, M. and P. A. Grayburn (2019). “Contrasting Effects of Pharmacological, Procedural, and Surgical Interventions on Proportionate and Disproportionate Functional Mitral Regurgitation in Chronic Heart Failure.” Circulation 140(9): 779-789.

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Two distinct pathways can lead to functional mitral regurgitation (MR) in patients with chronic heart failure and a reduced ejection fraction. When remodeling and enlargement of the left ventricle (LV) cause annular dilatation and tethering of the mitral valve leaflets, there is a linear relationship between LV end-diastolic volume and the effective regurgitant orifice area of the mitral valve. These patients, designated as having proportionate MR, respond favorably to treatments that lead to reversal of LV remodeling and a decrease in LV volumes (eg, neurohormonal antagonists and LV assist devices), but they may not benefit from interventions that are directed only at the mitral valve leaflets (eg, transcatheter mitral valve repair). In contrast, when ventricular dyssynchrony causes functional MR attributable to unequal contraction of the papillary muscles, the magnitude of regurgitation is greater than that predicted by LV volumes. These patients, designated as having severe but disproportionate MR, respond favorably to treatments that are directed to the mitral valve leaflets or their supporting structures (eg, cardiac resynchronization or transcatheter mitral valve repair), but they may derive little benefit from interventions that act only to reduce LV cavity size (eg, pharmacological treatments). This novel conceptual framework reflects the important interplay between LV geometry and mitral valve function in determining the clinical presentation of patients, and it allows characterization of the determinants of functional MR to guide the most appropriate therapy in the clinical setting.