DSR, or Direct Sodium Removal, is an emerging therapy for heart failure that pulls excess sodium directly out of the body through the lining of the abdomen. Unlike traditional diuretics (water pills), which force the kidneys to flush out sodium and water together, DSR bypasses the kidneys entirely. This makes it particularly relevant for people whose kidneys have stopped responding well to diuretics, a problem known as diuretic resistance.
How DSR Works
The basic concept borrows from peritoneal dialysis, a technique kidney patients have used for decades. A thin tube called a catheter is placed into the peritoneal cavity, the space inside your abdomen that surrounds your intestines. Through that tube, a specially formulated solution is infused and left to sit for about two hours. During that dwell time, sodium from your blood crosses through the peritoneal membrane (the thin tissue lining your abdomen) and into the solution. The fluid is then drained out, taking the sodium with it.
What makes DSR different from standard peritoneal dialysis is the solution itself. DSR uses a sodium-free 10% dextrose solution. Because this fluid contains zero sodium, it creates a steep concentration gradient: sodium in your blood has nowhere to go but into the solution. Early animal and human studies found that more than half of the total sodium removal happens within the first two hours, which is why the procedure uses a two-hour dwell as its standard timeframe. Each session uses about one liter of solution.
Why Sodium Matters in Heart Failure
In heart failure, the heart can’t pump blood efficiently. The body responds by holding onto sodium and water, trying to maintain blood pressure and circulation. Over time, this creates a vicious cycle: fluid builds up in the lungs, legs, and abdomen, making the heart work even harder. Doctors typically prescribe loop diuretics to force the kidneys to excrete that extra sodium and water.
The problem is that many heart failure patients eventually develop diuretic resistance. Their kidneys adapt and stop responding to even high doses of these medications. When that happens, fluid keeps accumulating, symptoms worsen, and hospitalizations become frequent. This is the gap DSR is designed to fill. By removing sodium through the abdomen instead of the kidneys, it offers an alternative route that doesn’t depend on kidney function at all.
What the Clinical Evidence Shows
DSR has been studied in two key clinical trials: RED DESERT and SAHARA. Both enrolled patients with heart failure who were taking high doses of diuretics (at least 80 mg of furosemide or equivalent daily) and still struggling with fluid overload. In these studies, loop diuretics were withdrawn entirely, and serial DSR sessions were used to achieve and maintain a balanced fluid state.
The results were striking across several measures. Patients saw improvements in volume status, kidney function, and cardiovascular markers. Their response to diuretics normalized, allowing dramatically lower doses when diuretics were eventually reintroduced. Heart failure severity improved by one full NYHA class, which is the standard scale doctors use to rate how much the condition limits daily activity (going from Class III, where mild exertion causes symptoms, to Class II, where only moderate exertion does, for example). Perhaps most notably, none of the patients in these studies were rehospitalized for fluid overload, and their predicted one-year mortality dropped by 75% based on established heart failure risk models.
Who Is Eligible for DSR
DSR is not for every heart failure patient. The clinical trials targeted a specific population: people with a confirmed heart failure diagnosis who were already on high-dose diuretics and still retaining fluid. To qualify, patients needed a systolic blood pressure of at least 100 mmHg and kidneys that still had some baseline function (an eGFR above 30, which roughly means the kidneys are working at about 30% or better). Patients with elevated potassium levels were excluded because withdrawing diuretics tends to raise potassium further, which can be dangerous.
In practical terms, DSR is aimed at the sickest subset of heart failure patients: those who have run out of options with conventional diuretic therapy and face repeated hospital stays for congestion.
The Alfapump Device
The technology behind DSR is being developed by Sequana Medical, a company that created a fully implantable pump called the alfapump. Rather than requiring manual infusion and drainage each time, this device automates the process. The alfapump received FDA approval for commercialization in 2024 and is eligible for Medicare and Medicaid reimbursement, with additional new technology reimbursement available to help cover costs.
The device was originally developed for a different condition, refractory ascites (fluid buildup in the abdomen from liver disease), and has since been adapted for the heart failure application. The implantable design is significant because DSR works best as a repeated, ongoing therapy rather than a one-time procedure. Having an automated system removes the burden of frequent manual treatments.
How DSR Fits Into Heart Failure Treatment
DSR is not replacing standard heart failure medications. The established treatment pathway still starts with combinations of drugs that reduce strain on the heart and help the kidneys excrete fluid. Current guidelines emphasize natriuresis-guided diuretic therapy, meaning doctors measure how much sodium patients are actually excreting and adjust doses accordingly. DSR enters the picture when that standard approach fails.
One of the more interesting findings from the clinical studies is that DSR didn’t just serve as a bridge. After treatment, patients’ diuretic response actually improved, suggesting that removing the excess sodium burden may help “reset” the kidneys’ ability to respond to medications. This could mean that some patients who undergo DSR might eventually return to lower, more effective diuretic doses rather than needing the therapy indefinitely, though longer-term data will clarify how durable that benefit is.