For years, the lymphatic system has remained in the shadow of the circulatory system—little known, rarely discussed, yet crucial for maintaining balance in the body. The latest research shows that its efficiency may determine the success of therapy for one of the most dangerous diseases of our time: acute heart failure. 

A study published in the prestigious European Journal of Heart Failure by a team of scientists from Wroclaw Medical University and Duke University School of Medicine, titled “Lower extremity lymphatic flow is associated with diuretic response in acute heart failure,” demonstrated that the rate of lymph flow in the lower limbs of patients correlates with their response to diuretic treatment—the basic tool in acute heart failure therapy. 

Acute heart failure is a condition in which the heart is unable to pump sufficient blood. One of the most dangerous symptoms is fluid congestion—swelling of the lower limbs, fluid in the abdominal cavity, or lungs. Standard treatment involves administering diuretics, which help eliminate excess water from the body. Unfortunately, in some patients, these drugs are ineffective, a phenomenon known as diuretic resistance. 

Until now, kidney dysfunction was considered the primary cause of this resistance. However, studies by the teams from Wroclaw and Duke point to a key role of the lymphatic system—a delicate network of vessels responsible for collecting and transporting fluid from the spaces between cells back into the bloodstream. If lymph flow is slowed, the body’s dehydration process is impaired. 

To study lymph flow, researchers used an advanced lymphography technique with indocyanine green (ICG)—a fluorescent dye that highlights lymphatic pathways. Sixty-five patients hospitalized for acute heart failure were examined. The results were clear: patients whose lymph flowed faster and more efficiently showed better responses to diuretic treatment. 

These findings open a new treatment perspective: improving lymphatic system function could become a component of more effective heart failure therapy. Various supportive methods are currently being tested—from physical therapies (compression therapy, lymphatic drainage) and medical technologies to potential pharmacological therapies targeting lymphatic vessels. 

A connection was also noted between weaker lymph flow and higher aldosterone levels—a hormone that retains salt and water in the body, worsening swelling. This may indicate a new area for therapeutic intervention related to modulation of the renin-angiotensin-aldosterone system. 

Previously, the lymphatic system was often treated as a “secondary” part of the circulatory system. Research from Wroclaw and Duke shows that it may play a crucial role in the effectiveness of acute heart failure treatment. If further studies confirm these results, the lymphatic system will become a significant new therapeutic target, supporting both the heart and kidneys.