Direct Interstitial Decongestion in an Animal Model of Acute-on-Chronic Ischemic Heart Failure

Cardio-Renal Syndrome: Latest Developments in Device-Based Therapy

Background: Cardio-renal syndrome (CRS) is a complex condition involving bidirectional dysfunction of the heart and kidneys, in which the failure of one organ exacerbates failure in the other. Traditional pharmacologic treatments are often insufficient to manage the hemodynamic and neurohormonal abnormalities underlying CRS, especially in cases resistant to standard therapies. Device-based therapies have emerged as a promising adjunct or alternative approach, offering targeted intervention to relieve congestion, improve renal perfusion, and modulate hemodynamics. This study aimed to evaluate the efficacy and safety of various device-based therapies in CRS management, utilizing DRI2P2S classification to categorize interventions as dilators, reducers, interstitial modulators, pullers, pushers, and shifters. Methods: A comprehensive analysis of clinical trial data and observational studies involving device-based therapies in patients with CRS was conducted, with a focus on hemodynamic endpoints, renal and cardiac function, symptom relief, and adverse events. Devices included in the analysis were splanchnic denervation systems (dilators), devices for central and pulmonary pressure reduction (reducers), and systems targeting interstitial fluid (fluid shifters), among others. A systematic literature review from 2004 to 2024 was performed using databases including PubMed, Embase, and ClinicalTrials.gov, following PRISMA guidelines for study selection. Data were extracted on patient demographics, device type, trial design, outcomes, and follow-up duration. Results: Device-based therapies demonstrated varying levels of efficacy in CRS, with significant improvements observed in specific parameters. Notable results were a reduction in central venous pressure and improved diuretic responsiveness in acute CRS cases, while also stabilizing or improving renal function. Other relevant endpoints were fewer heart failure hospitalizations and a reduction in renal adverse events, reduced tissue congestion and improved quality of life scores. However, some devices presented challenges, including procedure-related complications and a learning curve for optimal device implantation. Conclusions: Device-based therapies offer a valuable addition to the CRS treatment paradigm, particularly in cases unresponsive to conventional diuretics and other pharmacologic measures. Each of them addresses specific pathophysiological components of CRS and shows promise in improving clinical outcomes. Nevertheless, further large-scale, long-term trials with comprehensive endpoints are needed to establish these therapies' roles in standard care and to optimize patient selection criteria. Enhanced understanding of device mechanisms and refinement of trial endpoints will be key to maximizing the impact of these therapies on quality of life and clinical outcomes for CRS patients.

Device therapies for heart failure with reduced ejection fraction: a new era

Even with significant advancements in the treatment modalities for patients with heart failure (HF), the rates of morbidity and mortality associated with HF are still high. Various therapeutic interventions, including cardiac resynchronization therapy, Implantable Cardiovascular-Defibrillators, and left ventricular assist devices, are used for HF management. Currently, more research and developments are required to identify different treatment modalities to reduce hospitalization rates and improve the quality of life of patients with HF. In relation to this, various non-valvular catheter-based therapies have been recently developed for managing chronic HF. These devices target the pathophysiological processes involved in HF development including neurohumoral activation, congestion, and left ventricular remodeling. The present review article aimed to discuss the major transcatheter devices used in managing chronic HF. The rationale and current clinical developmental stages of these interventions will also be addressed in this review.

Advances in preclinical surgical therapy of cardiovascular diseases

Cardiovascular disease is the most common cause of death worldwide, resulting in millions of deaths annually. Currently, there are still some deficiencies in the treatment of cardiovascular diseases. Innovative surgical treatments are currently being developed and tested in response to this situation. Large animal models, which are similar to humans in terms of anatomy, physiology, and genetics, play a crucial role in connecting basic research and clinical applications. This article reviews recent preclinical studies and the latest clinical advancements in cardiovascular disease based on large animal models, with a focus on targeted delivery, neural regulation, cardiac remodeling, and hemodynamic regulation. It provides new perspectives and ideas for clinical translation and offers new methods for clinical treatment.

Lower Extremity Lymphatic Flow/Drainage Assessment by Indocyanine Green Fluorescent Lymphography in Heart Failure Patients

The purpose of this study was to present a protocol for visualizing lymphatic flow in patients with heart failure (HF) by using indocyanine green fluorescence lymphography. We studied 37 subjects: 20 patients with acute heart failure (AHF) and lower limb edema, 7 patients with chronic heart failure (CHF) without lower limb edema, and 10 control subjects (no HF, no limb edema). All subjects were assessed at rest, and 11 subjects (6 control and 5 with CHF) were assessed again after a 10-minute walk. The lymph flow was visualized in all selected patients without complications. At rest, there was either no lymph flow or minimal lymph flow in all control subjects and patients with CHF, whereas the majority of patients with AHF demonstrated significant lymph flow. This study describes a new method to visualize/assess lymphatic flow in patients with HF, allowing for continuous, real-time tracking of lymphatic flow in the lower extremity.

Advances in lymphedema: An under-recognized disease with a hopeful future for patients

Lymphedema has traditionally been underappreciated by the healthcare community. Understanding of the underlying pathophysiology and treatments beyond compression have been limited until recently. Increased investigation has demonstrated the key role of inflammation and resultant fibrosis and adipose deposition leading to the clinical sequelae and associated reduction in quality of life with lymphedema. New imaging techniques including magnetic resonance imaging (MRI), indocyanine green lymphography, and high-frequency ultrasound offer improved resolution and understanding of lymphatic anatomy and flow. Nonsurgical therapy with compression, exercise, and weight loss remains the mainstay of therapy, but growing surgical options show promise. Physiologic procedures (lymphovenous anastomosis and vascularized lymph node transfers) improve lymphatic flow in the diseased limb and may reduce edema and the burden of compression. Debulking, primarily with liposuction to remove the adipose deposition that has accumulated, results in a dramatic decrease in limb girth in appropriately selected patients. Though early, there are also exciting developments of potential therapeutic targets tackling the underlying drivers of the disease. Multidisciplinary teams have developed to offer the full breadth of evaluation and current management, but the development of a greater understanding and availability of therapies is needed to ensure patients with lymphedema have greater opportunity for optimal care.

Relationship of Vascular Endothelial Growth Factor C, a Lymphangiogenesis Modulator, With Edema Formation, Congestion and Outcomes in Acute Heart Failure

BACKGROUND

Although vascular endothelial growth factor C (VEGF-C) is a known lymphangiogenesis modulator, its relationship with congestion formation and outcomes in acute heart failure (AHF) is unknown.

METHODS

Serum VEGF-C levels were measured in 237 patients hospitalized for AHF. The population was stratified by VEGF-C levels and linked with clinical signs of congestion and outcomes.

RESULTS

The study's population was divided in VEGF-C tertiles: low (median [Q25-Q75]: 33 [15-175]), medium (606 [468-741]) and high (1141 [968-1442] pg/mL). The group with low VEGF-C on admission presented with the highest prevalence of severe lower-extremity edema (low VEGF-C vs medium VEGF-C vs high VEGF-C): 30% vs 13% vs 20%; P = 0.02); the highest percentage of patients with ascites: 22% vs 9% vs 6%; P = 0.006; and the lowest proportion of patients with pulmonary congestion: 22% vs 30% vs 46%; P = 0.004. The 1-year mortality rate was the highest in the low VEGF-C tertile: 35% vs 28% vs 18%, respectively; P = 0.049. The same pattern was observed for the composite endpoint (death and AHF rehospitalization): 45% vs 43% vs 26%; P = 0.029. The risks of death at 1-year follow-up and composite endpoint were significantly lower in the high VEGF-C group.

CONCLUSIONS

Low VEGF-C was associated with more severe signs of congestion (signs of fluid accumulation) and adverse clinical outcomes.

Role of Lymphatics in Heart Failure

The lymphatic system plays a crucial, yet often overlooked, role in maintaining fluid homeostasis, and its dysregulation is a key feature of heart failure (HF). Lymphatic dysregulation in patients with HF typically results from a combination of self-perpetuating congestive mechanisms, such as increased fluid filtration, decreased lymph drainage into the central venous system, impaired lymph vessel integrity, dysfunctional lymphatic valves, and dysfunctional renal lymphatic system. These pathomechanisms collectively overwhelm the lymphatic system and hinder its ability to decongest the interstitial space with subsequent manifestation and progression of clinical congestion. Targeting the lymphatic system to counteract these congestive pathomechanisms and facilitate interstitial fluid removal represents a novel pathway to treat congestion in HF. In this study, we discuss the physiological roles of the lymphatic system in fluid homeostasis and the pathophysiological alteration of these roles in HF. We also discuss innovative technologies that aim to use the lymphatic system pathway to treat congestion in HF and provide future directions related to these approaches.

Device-based therapies for decompensated heart failure

PURPOSE OF REVIEW

Despite improvements in medical therapies, patients with heart failure continue to suffer significant morbidity and mortality. Acute decompensated heart failure (ADHF) remains a common and serious medical condition with a myriad of implications on patient survival and quality of life, and heart failure related readmissions persist [1-3].

RECENT FINDINGS

From the detection of prehospitalization decompensation and inpatient management of ADHF to stabilization of cardiogenic shock and durable mechanical circulatory support, device-based therapies are utilized across the spectrum of heart failure management. At present, there are numerous device-based therapies commonly used in clinical practice and many more devices in the early clinical-trial phase aimed at attenuation of ADHF.

SUMMARY

In this review, we examine recent updates in the breadth and use of devices-based therapies in these three main domains: ambulatory heart failure, acute decompensated heart failure, and cardiogenic shock. Device-based therapies for decompensated heart failure will continue to grow in number, indication, and complexity, making recognition and familiarity with available technologies of increased importance for research and clinical practice.

Role of the Renal Lymphatic System in Heart Failure

PURPOSE OF REVIEW

The lymphatic system plays a major but overlooked role in maintaining fluid homeostasis. Given the unique fluid homeostasis functions of the kidneys, dysregulation of the renal lymphatic system underlies the development of self-propagating congestive pathomechanisms. In this review, we outline the roles of the renal lymphatic system in heart failure (HF).

RECENT FINDINGS

Studies have uncovered several pathomechanisms involving the renal lymphatic system in congestive states, such as impaired interstitial draining by the renal lymphatic system, impaired structure and valves of renal lymphatics, lymphatic-induced increase in renal reabsorption of water and sodium, and development of albuminuria with proteinuria-induced renal lymphangiogenesis. These self-propagating mechanisms result in "renal tamponade" with manifestations of cardiorenal syndrome and inappropriate renal response to diuretics. Dysregulation of the renal lymphatic system is integral to the development and progression of congestion in HF. Targeting renal lymphatics may provide a novel pathway to treat intractable congestion.

Transcatheter interventions for heart failure

Despite significant advances in the medical management of patients living with heart failure, there continues to be significant morbidity and mortality associated with the condition. There is a growing need for research and development of additional modalities to fill the management and treatment gaps, reduce hospitalisations and improve the quality of life for patients living with heart failure. In the last decade, there has been a rapid rise in the use of non-valvular catheter-based therapies for the management of chronic heart failure to complement existing guideline-directed management. They target well-defined mechanistic and pathophysiological processes critical to the progression of heart failure including left ventricular remodelling, neurohumoral activation, and congestion. In this review, we will explore the physiology, rationale, and current stages of the clinical development of the existing procedures.

Device-based therapy for decompensated heart failure: An updated review of devices in development based on the DRI2P2S classification

Congestive heart failure (HF) is a devastating disease leading to prolonged hospitalization, high morbidity and mortality rates, and increased costs. Well-established treatments for decompensated or unstable patients include medications and mechanical cardiac support devices. For acute HF decompensation, new devices are being developed to help relieve symptoms and recover heart and renal function in these patients. A recent device-based classification scheme, collectively classified as DRI2P2S, has been proposed to better describe these new device-based therapies based on their mechanism: dilators (increase venous capacitance), removers (direct removal of sodium and water), inotropes (increase left ventricular contractility), interstitials (accelerate removal of lymph), pushers (increase renal arterial pressure), pullers (decrease renal venous pressure), and selective (selective intrarenal drug infusion). In this review, we describe the new class of medical devices with the most current results reported in preclinical models and clinical trials.

Modern Approaches for the Treatment of Heart Failure: Recent Advances and Future Perspectives

Heart failure (HF) is a progressively deteriorating medical condition that significantly reduces both the patients' life expectancy and quality of life. Even though real progress was made in the past decades in the discovery of novel pharmacological treatments for HF, the prevention of premature deaths has only been marginally alleviated. Despite the availability of a plethora of pharmaceutical approaches, proper management of HF is still challenging. Thus, a myriad of experimental and clinical studies focusing on the discovery of new and provocative underlying mechanisms of HF physiopathology pave the way for the development of novel HF therapeutic approaches. Furthermore, recent technological advances made possible the development of various interventional techniques and device-based approaches for the treatment of HF. Since many of these modern approaches interfere with various well-known pathological mechanisms in HF, they have a real ability to complement and or increase the efficiency of existing medications and thus improve the prognosis and survival rate of HF patients. Their promising and encouraging results reported to date compel the extension of heart failure treatment beyond the classical view. The aim of this review was to summarize modern approaches, new perspectives, and future directions for the treatment of HF.

The interstitial compartment as a therapeutic target in heart failure

Congestion is the single most important contributor to heart failure (HF) decompensation. Most of the excess volume in patients with HF resides in the interstitial compartment. Inadequate decongestion implies persistent interstitial congestion and is associated with worse outcomes. Therefore, effective interstitial decongestion represents an unmet need to improve quality of life and reduce clinical events. The key processes that underlie incomplete interstitial decongestion are often ignored. In this review, we provide a summary of the pathophysiology of the interstitial compartment in HF and the factors governing the movement of fluids between the interstitial and vascular compartments. Disruption of the extracellular matrix compaction occurs with edema, such that the interstitium becomes highly compliant, and large changes in volume marginally increase interstitial pressure and allow progressive capillary filtration into the interstitium. Augmentation of lymph flow is required to prevent interstitial edema, and the lymphatic system can increase fluid removal by at least 10-fold. In HF, lymphatic remodeling can become insufficient or maladaptive such that the capacity of the lymphatic system to remove fluid from the interstitium is exceeded. Increased central venous pressure at the site of the thoracic duct outlet also impairs lymphatic drainage. Owing to the kinetics of extracellular fluid, microvascular absorption tends to be transient (as determined by the revised Starling equation). Therefore, effective interstitial decongestion with adequate transcapillary plasma refill requires a substantial reduction in plasma volume and capillary pressure that are prolonged and sustained, which is not always achieved in clinical practice. The critical importance of the interstitium in the congestive state underscores the need to directly decongest the interstitial compartment without relying on the lowering of intracapillary pressure with diuretics. This unmet need may be addressed by novel device therapies in the near future.

Novel Therapeutic Devices in Heart Failure

Heart failure (HF) constitutes a significant clinical problem and is associated with a sizeable burden for the healthcare system. Numerous novel techniques, including device interventions, are investigated to improve clinical outcome. A review of the most notable currently studied devices targeting pathophysiological processes in HF was performed. Interventions regarding autonomic nervous system imbalance, i.e., baroreflex activation therapy; vagus, splanchnic and cardiopulmonary nerves modulation; respiratory disturbances, i.e., phrenic nerve stimulation and synchronized diaphragmatic therapy; decongestion management, i.e., the Reprieve system, transcatheter renal venous decongestion system, Doraya, preCardia, WhiteSwell and Aquapass, are presented. Each segment is divided into subsections: potential pathophysiological target, existing evidence and weaknesses or unexplained issues. Novel therapeutic devices represent great potential in HF therapy management; however, further evidence is necessary to fully evaluate their utility.