V2receptor antagonism with tolvaptan in heart failure

Diuretic Combination Therapy in Acute Heart Failure: An Updated Review

Loop diuretics are the cornerstone of decongestive therapy in patients presenting with acute heart failure and have been extensively studied in randomized clinical trials. Therefore, in current guidelines, they are the only drug with a class I recommendation to treat signs and symptoms of congestion when present. However, the percentage of patients achieving successful decongestion is suboptimal, and diuretic resistance frequently develops. Patients with a poor response to loop diuretics and those discharged with residual signs of congestion are characterized by a worse prognosis over time. Recently, a renovated interest in different diuretic classes sprouted among heart failure researchers in order to improve decongestion strategies and ameliorate short- and long-term clinical outcomes. Randomized clinical trials investigating associations among diuretic classes and loop diuretics have been performed but yielded variable results. Therefore, despite initial evidence of a possible benefit from some of these compounds, a definite way to approach diuretic resistance via diuretic combination therapy is still missing. The aim of this review is to summarize current clinical evidence on the use of diuretic combination therapy in patients with acute heart failure and to suggest a possible approach to avoid or counteract diuretic resistance.

Right Heart Function in Cardiorenal Syndrome

PURPOSE OF REVIEW

Since CRS is critically dependent on right heart function and involved in interorgan crosstalk, assessment and monitoring of both right heart and kidney function are of utmost importance for clinical outcomes. This systematic review aims to comprehensively report on novel diagnostic and therapeutic paradigms that are gaining importance for the clinical management of the growing heart failure population suffering from CRS.

RECENT FINDINGS

Cardiorenal syndrome (CRS) in patients with heart failure is associated with poor outcome. Although systemic venous congestion and elevated central venous pressure have been recognized as main contributors to CRS, they are often neglected in clinical practice. The delicate hemodynamic balance in CRS is particularly determined by the respective status of the right heart. The consideration of hemodynamic and CRS profiles is advantageous in tailoring treatment for better preservation of renal function. Assessment and monitoring of right heart and renal function by known and emerging tools like renal Doppler ultrasonography or new biomarkers may have direct clinical implications.

Emerging Treatments of Cardiorenal Syndrome: An Update on Pathophysiology and Management

Cardiorenal syndrome refers to combined cardiac and renal dysfunction that adversely impacts both organs and is also associated with severe clinical outcomes. The pathophysiology is believed to be multifactorial and complex. Increased central venous pressure and intra-abdominal pressure, overactivation of the Renin-Angiotensin-Aldosterone System (RAAS), systemic illnesses like sepsis, amyloidosis, diabetes are important factors in developing the cardiorenal syndrome. Our review article attempts to review the pathophysiology and treatment aspect of cardiorenal syndrome and explores potential therapeutic strategies that can be adopted for the management.

We searched PubMed, EMBASE, Google Scholar for relevant articles using different keywords and Medical Subject Headings, and finalized 38 articles to be included in our study. Cardiorenal syndrome management aims to eliminate venous congestion and fluid retention, which leads to improved cardiorenal status. This is usually achieved using pharmacologic agents like diuretics, vasodilators, inotropes, angiotensin-converting enzyme inhibitors (ACEIs)/angiotensin II receptor blockers (ARBs), neprilysin inhibitors, and extracorporeal methods like ultrafiltration. The use of therapeutic agents such as sodium-glucose co-transporter 2 inhibitors and tolvaptan (a vasopressin V2 receptor antagonist), and cardiac resynchronization therapy has also been shown to have potential benefits in managing the disease. These agents can be instrumental in the management and require large-scale clinical trials specifically aimed at improving cardiorenal outcomes based on severity and type of cardiorenal syndrome.

Vasopressin-receptor antagonists

Despite a crucial role in body fluid homeostasis, elevated vasopressin levels can also be pathological in conditions such as congestive heart failure, liver cirrhosis and the syndrome of inappropriate antidiuretic hormone secretion. The result of elevated vasopressin is renal water retention and hyponatremia, a low serum sodium concentration. Hyponatremia is associated with excess morbidity and mortality. Nonpeptide vasopressin-receptor antagonists represent a new drug class of small molecules that competitively inhibit one or more of the vasopressin receptors. There are three vasopressin receptors in humans, including V1a, V1b and V2. Selective V2- and combined V1a/V2-receptor antagonists have been developed for the treatment of hyponatremia resulting from congestive heart failure, liver cirrhosis and the syndrome of inappropriate antidiuretic hormone secretion. Two nonpeptide vasopressin-receptor antagonists, conivaptan and tolvaptan, have recently been approved by American and European drug authorities for clinical use. This article aims to provide a succinct and clinical update on nonpeptide vasopressin-receptor antagonists, including their mechanism of action, performance in randomized clinical trials and current clinical status.