Renal function in advanced heart failure

The role and application of current pharmacological management in patients with advanced heart failure

In the last decades, several classifications and definitions have been proposed for advanced heart failure (ADVHF) patients, including clinical, functional, hemodynamic, imaging, and electrocardiographic features. Despite different inclusion criteria, ADVHF is characterized by some common items, such as drug intolerance, low arterial pressure, multiple organ dysfunction, chronic kidney disease, and diuretic use dependency. Additional features include fatigue, hypotension, hyponatremia, and unintentional weight loss associated with a specific laboratory profile reflecting systemic multiorgan dysfunction. Notably, studies evaluating guideline-directed medical therapy recently endorsed by guidelines in stable HF, including the 4 drug classes all together (i.e., betablocker, mineral corticoid antagonist, renin angiotensin inhibitors/neprilysin inhibitors, and sodium glucose transporter inhibitors), remain scarcely analyzed in ADVHF and New York Heart Association (NYHA) Class IV. Additionally, due to the common conditions associated with advanced stages, the balance between drug tolerance and potential benefits of the contemporary use of all agents is questioned. Therefore, less hard endpoints, such as exercise tolerance, quality of life (QoL) and self-competency, are not clearly demonstrated. Specific analyses evaluating outcome and rehospitalization of each drug provided conflicting results and are often limited to subjects with stable conditions and less advanced NYHA class. Current European Society of Cardiology/American Heart Association (ESC/AHA) Guidelines do not indicate the type of treatment, dosage, and administration modalities, and they do not suggest specific indications for ADVHF patients. Due to these concerns, there is an impelling need to understand what drugs may be used as the first line, what management leads to the better outcome, and what is the best treatment algorithm in this setting. In this paper, we summarize the most common pitfalls and limitations for the use of the traditional agents, and we propose a personalized approach aiming at preserve drug tolerance and maintaining adverse event protection and satisfactory QoL.

Specific Afferent Renal Denervation Prevents Reduction in Neuronal Nitric Oxide Synthase Within the Paraventricular Nucleus in Rats With Chronic Heart Failure

Renal denervation (RDN) has been shown to restore endogenous neuronal nitric oxide synthase (nNOS) in the paraventricular nucleus (PVN) and reduce sympathetic drive during chronic heart failure (CHF). The purpose of the present study was to assess the contribution of afferent renal nerves to the nNOS-mediated sympathetic outflow within the PVN in rats with CHF. CHF was induced in rats by ligation of the left coronary artery. Four weeks after surgery, selective afferent RDN (A-RDN) was performed by bilateral perivascular application of capsaicin on the renal arteries. Seven days after intervention, nNOS protein expression, nNOS immunostaining signaling, and diaphorase-positive stained cells were significantly decreased in the PVN of CHF rats, changes that were reversed by A-RDN. A-RDN reduced basal lumbar sympathetic nerve activity in rats with CHF (8.5%±0.5% versus 17.0%±1.2% of max). Microinjection of nNOS inhibitor L-NMMA (L-N^G-monomethyl arginine citrate) into the PVN produced a blunted increase in lumbar sympathetic nerve activity in rats with CHF. This response was significantly improved after A-RDN (Δ lumbar sympathetic nerve activity: 25.7%±2.4% versus 11.2%±0.9%). Resting afferent renal nerves activity was substantially increased in CHF compared with sham rats (56.3%±2.4% versus 33.0%±4.7%). These results suggest that intact afferent renal nerves contribute to the reduction of nNOS in the PVN. A-RDN restores nNOS and thus attenuates the sympathoexcitation. Also, resting afferent renal nerves activity is elevated in CHF rats, which may highlight a crucial neural mechanism arising from the kidney in the maintenance of enhanced sympathetic drive in CHF.

Bleeding with the artificial heart: Gastrointestinal hemorrhage in CF-LVAD patients

Continuous-flow left ventricular assist devices (CF-LVADs) have significantly improved outcomes for patients with end-stage heart failure when used as a bridge to cardiac transplantation or, more recently, as destination therapy. However, its implantations carries a risk of complications including infection, device malfunction, arrhythmias, right ventricular failure, thromboembolic disease, postoperative and nonsurgical bleeding. A significant number of left ventricular assist devices (LVAD) recipients may experience recurrent gastrointestinal hemorrhage, mainly due to combination of antiplatelet and vitamin K antagonist therapy, activation of fibrinolytic pathway, acquired von Willebrand factor deficiency, and tendency to develop small intestinal angiodysplasias due to increased rotary speed of the pump. Gastrointestinal bleeding in LVAD patients remains a source of increased morbidity including the need for blood transfusions, extended hospital stays, multiple readmissions, and overall mortality. Management of gastrointestinal bleeding in LVAD patients involves multidisciplinary approach in stabilizing the patients, addressing risk factors and performing structured endoluminal evaluation with focus on upper gastrointestinal tract including jejunum to find and eradicate culprit lesion. Medical and procedural intervention is largely successful and universal bleeding cessation occurs in transplanted patients.

Heart Failure and Kidney Disease

Kidney disease is commonly found in heart failure (HF) patients. They share many risk factors and common pathophysiological pathways which often lead to mutual dysfunction. Both haemodynamic and non-haemodynamic mechanisms are involved in the development of renal impairment in heart failure patients. Moreover, the presence of a chronic kidney disease is a significant independent predictor of worse outcome in chronic as well as in acute decompensated HF. As a consequence, an accurate evaluation of renal function plays a key role in the management of HF patients. Serum creatinine levels and glomerular filtration rate (GFR) estimates are the corner stones of renal function evaluation in clinical practice. However, to overcome their limits, several emerging glomerular and tubular biomarkers have been proposed over the last years. Alongside the renal biomarkers, imaging techniques could complement the laboratory data exploring different pathophysiological pathways. In particular, Doppler evaluation of renal circulation is a highly feasible technique that can effectively identify HF patients prone to develop renal dysfunction and with a worse outcome. Finally, some classes of drugs currently used in heart failure treatment can affect renal function and their use can be influenced by the presence of chronic kidney disease.

Integration of renal sensory afferents at the level of the paraventricular nucleus dictating sympathetic outflow

The sympathetic nervous system has been identified as a major contributor to the pathophysiology of chronic heart failure (CHF) and other diseases such as hypertension and diabetes, both in experimental animal models and patients. The kidneys have a dense afferent sensory innervation positioning it to be the origin of multimodal input to the central nervous system. Afferent renal nerve (ARN) signals are centrally integrated, and their activation results in a general increase in sympathetic tone, which is directed toward the kidneys as well as other peripheral organs innervated by the sympathetic nerves. In the central nervous system, stimulation of ARN increases the neuronal discharge frequency and neuronal activity in the paraventricular nucleus (PVN) of the hypothalamus. The activity of the neurons in the PVN is attenuated during iontophoretic application of glutamate receptor blocker, AP5. An enhanced afferent renal input to the PVN may be critically involved in dictating sympathoexcitation in CHF. Furthermore, renal denervation abrogates the enhanced neuronal activity within the PVN in rats with CHF, thereby possibly contributing to the reduction in sympathetic tone. Renal denervation also restores the decreased endogenous levels of neuronal nitric oxide synthase (nNOS) in the PVN of rats with CHF. Overall, these data demonstrate that sensory information originating in the kidney excites pre-autonomic sympathetic neurons within the PVN and this "renal-PVN afferent pathway" may contribute to elevated sympathetic nerve activity in hyper-sympathetic disease conditions such as CHF and hypertension.

Calibrating the impact of dual RAAS blockade on the heart and the kidney - balancing risks and benefits

Overactivity of the renin-angiotensin-aldosterone system (RAAS) plays a key role in the pathophysiology of heart failure (HF) and chronic kidney disease (CKD). RAAS antagonists can significantly improve clinical outcomes, but monotherapy blocks but one step of the RAAS and can be bypassed through compensatory mechanisms. Providing more complete RAAS blockade by deploying drugs with complementary actions seemed logical - hence the practice of using dual (or triple) RAAS inhibitors. However, RAAS antagonists also exhibit dose-limiting side effects, including acute kidney injury, hyperkalaemia and hypotension, which blunt their overall effectiveness. Despite achieving better RAAS blockade, several trials failed to show clinical outcome improvements. Patients with concomitant CKD and HF (cardiorenal syndrome) are at the greatest risk of these adverse events and therefore the least able to benefit, yet they also have the worst prognosis. This paradox, where those most in need have fewest therapeutic options, poses three questions which are the focus of this review: whether (i) novel therapies that prevent adverse effects can restore therapeutic benefits to patients who would otherwise be RAAS-therapy intolerant, (ii) there are any validated alternatives to their use and (iii) newer approaches to the detection of fluid congestion are ready for implementation.

Renal Denervation Improves Exaggerated Sympathoexcitation in Rats With Heart Failure: A Role for Neuronal Nitric Oxide Synthase in the Paraventricular Nucleus

Renal denervation (RDN) has been postulated to reduce sympathetic drive during heart failure (HF), but the central mechanisms are not completely understood. The purpose of the present study was to assess the contribution of neuronal nitric oxide synthase (nNOS) within the paraventricular nucleus (PVN) in modulating sympathetic outflow in rats with HF that underwent RDN. HF was induced in rats by ligation of the left coronary artery. Four weeks after surgery, bilateral RDN was performed. Rats with HF had an increase in FosB-positive cells in the PVN with a concomitant increase in urinary excretion of norepinephrine, and both of these parameters were ameliorated after RDN. nNOS-positive cells immunostaining, diaphorase staining, and nNOS protein expression were significantly decreased in the PVN of HF rats, findings that were ameliorated by RDN. Microinjection of nNOS inhibitor N(G)-monomethyl l-arginine into the PVN resulted in a blunted increase in lumbar sympathetic nerve activity (11±2% versus 24±2%) in HF than in sham group. This response was normalized after RDN. Stimulation of afferent renal nerves produced a greater activation of PVN neurons in rats with HF. Afferent renal nerve stimulation elicited a greater increase in lumbar sympathetic nerve activity in rats with HF than in sham rats (45±5% versus 22±2%). These results suggest that intact renal nerves contribute to the reduction of nNOS in the PVN, resulting in the activation of the neurons in the PVN of rats with HF. RDN restores nNOS and thus attenuates the sympathoexcitation commonly observed in HF.

Focus on renal congestion in heart failure

Hospitalizations due to heart failure are increasing steadily despite advances in medicine. Patients hospitalized for worsening heart failure have high mortality in hospital and within the months following discharge. Kidney dysfunction is associated with adverse outcomes in heart failure patients. Recent evidence suggests that both deterioration in kidney function and renal congestion are important prognostic factors in heart failure. Kidney congestion in heart failure results from low cardiac output (forward failure), tubuloglomerular feedback, increased intra-abdominal pressure or increased venous pressure. Regardless of the cause, renal congestion is associated with increased morbidity and mortality in heart failure. The impact on outcomes of renal decongestion strategies that do not compromise renal function should be explored in heart failure. These studies require novel diagnostic markers that identify early renal damage and renal congestion and allow monitoring of treatment responses in order to avoid severe worsening of renal function. In addition, there is an unmet need regarding evidence-based therapeutic management of renal congestion and worsening renal function. In the present review, we summarize the mechanisms, diagnosis, outcomes, prognostic markers and treatment options of renal congestion in heart failure.

Role of renal sensory nerves in physiological and pathophysiological conditions

Whether activation of afferent renal nerves contributes to the regulation of arterial pressure and sodium balance has been long overlooked. In normotensive rats, activating renal mechanosensory nerves decrease efferent renal sympathetic nerve activity (ERSNA) and increase urinary sodium excretion, an inhibitory renorenal reflex. There is an interaction between efferent and afferent renal nerves, whereby increases in ERSNA increase afferent renal nerve activity (ARNA), leading to decreases in ERSNA by activation of the renorenal reflexes to maintain low ERSNA to minimize sodium retention. High-sodium diet enhances the responsiveness of the renal sensory nerves, while low dietary sodium reduces the responsiveness of the renal sensory nerves, thus producing physiologically appropriate responses to maintain sodium balance. Increased renal ANG II reduces the responsiveness of the renal sensory nerves in physiological and pathophysiological conditions, including hypertension, congestive heart failure, and ischemia-induced acute renal failure. Impairment of inhibitory renorenal reflexes in these pathological states would contribute to the hypertension and sodium retention. When the inhibitory renorenal reflexes are suppressed, excitatory reflexes may prevail. Renal denervation reduces arterial pressure in experimental hypertension and in treatment-resistant hypertensive patients. The fall in arterial pressure is associated with a fall in muscle sympathetic nerve activity, suggesting that increased ARNA contributes to increased arterial pressure in these patients. Although removal of both renal sympathetic and afferent renal sensory nerves most likely contributes to the arterial pressure reduction initially, additional mechanisms may be involved in long-term arterial pressure reduction since sympathetic and sensory nerves reinnervate renal tissue in a similar time-dependent fashion following renal denervation.

Platelet dysfunction and acquired von Willebrand syndrome in patients with left ventricular assist devices

OBJECTIVES

Unexplained bleeding events are a severe complication in patients with left ventricular assist devices (LVADs). Platelet dysfunction and acquired von Willebrand syndrome (AVWS) may contribute to bleeding tendencies. Yet, comprehensive data with respect to platelet function and AVWS in LVAD patients in terms of bleeding events are scarce.

METHODS

Thirty-nine HeartMate II patients were included in this study. Data of at least two time points were available for each patient. Platelet function was analysed via light transmission aggregometry in 19 patients without LVAD, 28 in early (≤14 days) and 30 in late postimplantation states (≥30 days). Von Willebrand factor (VWF) antigen, VWF collagen binding capacity and VWF multimeric analyses were performed in 26 patients without LVAD, 39 in early and 33 in late postimplantation states to diagnose AVWS. Bleeding complications were recorded for 39 patients in the early and 33 in the late postoperative period.

RESULTS

Platelet dysfunction was detectable in 18 of 19 without LVAD and in all patients following LVAD implantation. Platelet aggregation values did not change over time (without-early, P = 0.27, n = 14; early-late, P = 0.17, n = 21). AVWS was not diagnosed in patients without LVAD, except for one. On LVAD, 33 of 39 patients had AVWS in the early and all in the late period (n = 33). Bleeding events occurred in 44% of patients in the early and in 64% of patients in the late period.

CONCLUSIONS

According to our data, platelet aggregation is often impaired in LVAD patients even without an implanted LVAD. Additionally, appearance of AVWS seems to be closely linked to LVAD implantation.

Efficacy and safety of high dose versus low dose furosemide with or without dopamine infusion: the Dopamine in Acute Decompensated Heart Failure II (DAD-HF II) trial

AIMS

The role of low-dose dopamine infusion in patients with acute decompensated heart failure (ADHF) remains controversial. We aim to evaluate the efficacy and safety of high- versus low-dose furosemide with or without low-dose dopamine infusion in this patient population.

METHODS AND RESULTS

161 ADHF patients (78 years; 46% female; ejection fraction 31%) were randomized to 8-hour continuous infusions of: a) high-dose furosemide (HDF, n=50, 20mg/h), b) low-dose furosemide and low-dose dopamine (LDFD, n=56, 5mg/h and 5 μg kg(-1)min(-1) respectively), or c) low-dose furosemide (LDF, n=55, furosemide 5mg/h). The main outcomes were 60-day and one-year all-cause mortality (ACM) and hospitalization for HF (HHF). Dyspnea relief (Borg index), worsening renal function (WRF, rise in serum creatinine (sCr) ≥ 0.3mg/dL), and length of stay (LOS) were also assessed. The urinary output at 2, 4, 6, 8, and 24h was not significantly different in the three groups. Neither the ACM at day 60 (4.0%, 7.1%, and 7.2%; P=0.74) or at one year (38.1%, 33.9% and 32.7%, P=0.84) nor the HHF at day 60 (22.0%, 21.4%, and 14.5%, P=0.55) or one year (60.0%, 50.0%, and 47%, P=0.40) differed between HDF, LDFD, and LDF groups, respectively. No differences in the Borg index or LOS were noted. WRF was higher in the HDF than in LDFD and LDF groups at day 1 (24% vs. 11% vs. 7%, P<0.0001) but not at sCr peak (44% vs. 38% vs. 29%, P=0.27). No significant differences in adverse events were noted.

CONCLUSIONS

In ADHF patients, there were no significant differences in the in-hospital and post-discharge outcomes between high- vs. low-dose furosemide infusion; the addition of low-dose dopamine infusion was not associated with any beneficial effects.

The cardiorenal syndrome in heart failure: cardiac? renal? syndrome?

There has been increasing interest on the so-called cardiorenal syndrome (CRS), defined as a complex pathophysiological disorder of the heart and kidneys whereby acute or chronic dysfunction in one organ may induce acute or chronic dysfunction in the other. In this review, we contend that there is lack of evidence warranting the adoption of a specific clinical construct such as the CRS within the heart failure (HF) syndrome by demonstrating that: (a) the approaches and tools regarding the definition of kidney involvement in HF are suboptimal; (b) development of renal failure in HF is often confounded by age, hypertension, and diabetes; (c) worsening of renal function (WRF) in HF may be largely independent of alterations in cardiac function; (d) the bidirectional association between HF and renal failure is not unique and represents one of the several such associations encountered in HF; and (e) inflammation is a common denominator for HF and associated noncardiac morbidities. Based on these arguments, we believe that dissecting one of the multiple bidirectional associations in HF and constructing the so-called cardiorenal syndrome is not justified pathophysiologically. Fully understanding of all morbid associations and not only the cardiorenal is of great significance for the clinician who is caring for the patient with HF.

Renal dysfunction in heart failure

Renal dysfunction is a common, important comorbidity in patients with both chronic and acute heart failure (HF). Chronic kidney disease and worsening renal function (WRF) are associated with worse outcomes, but our understanding of the complex bidirectional interactions between the heart and kidney remains poor. When addressing these interactions, one must consider the impact of intrinsic renal disease resulting from medical comorbidities on HF outcomes. WRF may result from any number of important processes. Understanding the role of each of these factors and their interplay are essential in understanding how to improve outcomes in patients with renal dysfunction and HF.

Current status of mechanical circulatory support: a systematic review

Heart failure is a major public health problem and its management requires a significant amount of health care resources. Even with administration of the best available medical treatment, the mortality associated with the disease remains high. As therapeutical strategies for heart failure have been refined, the number of patients suffering from the disease has expanded dramatically. Although heart transplantation still represents the gold standard therapeutical approach, the implantation of mechanical circulatory support devices (MCSDs) evolved to a well-established management for this disease. The limited applicability of heart transplantation caused by a shortage of donor organs and the concurrent expand of the patient population with end-stage heart failure led to a considerable utilization of MCSDs. This paper outlines the current status of mechanical circulatory support.

Renal function has an effect on cardiovascular mortality in patients with dilated cardiomyopathy

BACKGROUND

Chronic heart failure (CHF) is a major and growing public health problem resulting from the cardiac damage caused by a variety of disease processes. CHF has many comorbid conditions such as hypertension, coronary artery disease, peripheral artery disease and chronic kidney disease (CKD). Some of the chronic conditions may have an effect on cardiac mortality in CHF patients. We have investigated the effect of renal dysfunction on cardiovascular mortality in patients with ischemic dilated cardiomyopathy (DCM) and nonischemic DCM.

METHODS

Six hundred and thirty-seven patients with DCM were evaluated between January 2003 and January 2011. All individuals in the study population were admitted to the cardiology clinic because of decompensated heart failure. In this prospective observational study, a total of 637 patients [409 men, 228 women, 18-94 years old, mean age 63 ± 13 years; New York Heart Association (NYHA) functional class II-IV] with diagnoses of ischemic (402) and nonischemic (235) DCM were enrolled in the study. Baseline glomerular filtration rate was calculated using the Cockcroft-Gault equation.

RESULTS

By the end of the study, 228 patients had died due to cardiovascular reasons. Both DCM types had similar cardiovascular mortality [151 patients with ischemic DCM (37%) vs. 77 patients with nonischemic DCM (32%); P = NS]. Renal dysfunction had an effect on cardiovascular mortality in patients with ischemic and nonischemic DCM (respectively, glomerular filtration rate 54 ± 24, 56 ± 24; P < 0.001).

CONCLUSION

We have demonstrated that renal function is a prognostic risk marker in patients with ischemic and nonischemic DCM.

Telemonitoring in chronic heart failure: a systematic review

Heart failure (HF) is a growing epidemic with the annual number of hospitalizations constantly increasing over the last decades for HF as a primary or secondary diagnosis. Despite the emergence of novel therapeutic approached that can prolong life and shorten hospital stay, HF patients will be needing rehospitalization and will often have a poor prognosis. Telemonitoring is a novel diagnostic modality that has been suggested to be beneficial for HF patients. Telemonitoring is viewed as a means of recording physiological data, such as body weight, heart rate, arterial blood pressure, and electrocardiogram recordings, by portable devices and transmitting these data remotely (via a telephone line, a mobile phone or a computer) to a server where they can be stored, reviewed and analyzed by the research team. In this systematic review of all randomized clinical trials evaluating telemonitoring in chronic HF, we aim to assess whether telemonitoring provides any substantial benefit in this patient population.