New Kidney Stone Tech Slashes Complications, Aims to Set New Standard

PLEASANTON, CA – February 26, 2026 – By Amanda Clark

Newly published clinical data on a revolutionary kidney stone treatment system is challenging long-held standards of success in urology, promising a future with significantly fewer post-procedure complications and a lower burden on the healthcare system. Calyxo, Inc.'s CVAC System, an all-in-one device for clearing kidney stones, demonstrated in two major studies that it not only removes stones with remarkable efficiency but also drastically reduces the rate of unplanned emergency visits, hospitalizations, and retreatments for patients over the long term.

The findings, detailed in the peer-reviewed Journal of Endourology, suggest a paradigm shift away from simply declaring a patient 'stone-free' and toward a more precise, predictive measure: minimizing the volume of stone fragments left behind.

A New Benchmark for Success

The most compelling evidence comes from the ASPIRE randomized controlled trial, the first study to track outcomes for a stone aspiration procedure over a two-year period. Patients treated with the CVAC System in a procedure known as Steerable Ureteral Renal Evacuation (SURE) experienced 73% fewer healthcare consumption events (HCEs) compared to those who underwent standard ureteroscopy with a basket to retrieve fragments. The study documented only three such events in the CVAC group versus 20 in the standard care group.

This dramatic reduction in long-term problems is attributed to the system's ability to leave behind an exceptionally small amount of residual stone volume (RSV). A second study, CLEARANCE, reinforced this, showing the second-generation CVAC System achieved a 96% mean clearance rate, leaving a mean RSV of just 14.1 mm³.

For decades, the benchmark for a successful kidney stone procedure has been the 'stone-free rate' (SFR), a binary measure that often varies based on imaging quality and definition. The ASPIRE trial, however, used high-resolution CT scans to prove that RSV is a far more reliable predictor of a patient's future. Patients with lower RSV were significantly less likely to experience the painful and costly complications that often follow traditional procedures.

“ASPIRE challenges how we define success in kidney stone removal,” said Thomas Chi, M.D., M.B.A., Professor and Chair for the University of Alabama at Birmingham Department of Urology, and senior author on the ASPIRE publication. “The study identifies residual stone volume as an important predictor of patient outcomes and shows that minimizing stone volume with the CVAC System can reduce unplanned hospital visits, events that carry substantial clinical and economic impact.”

The Economic Ripple Effect

The clinical benefits for patients—less pain, anxiety, and disruption—are mirrored by a profound potential economic impact. Kidney stone disease is a major driver of healthcare costs in the United States, projected to reach $4.1 billion in annual direct treatment costs by 2030. A significant portion of this expense comes from managing the aftermath of procedures, where residual fragments can lead to infection, blockage, and the need for further intervention.

The 73% reduction in HCEs observed in the ASPIRE trial points to a direct path for substantial cost savings. Fewer emergency department visits, hospital readmissions, and repeat surgeries would alleviate financial pressure on patients, insurers, and hospitals alike. Furthermore, the second-generation CVAC System has demonstrated improved procedural efficiency. The CLEARANCE trial reported a mean procedure time of just 46.4 minutes, a significant reduction from the first-generation device, freeing up valuable and expensive operating room time.

An Integrated Approach to Stone Removal

Unlike traditional multi-step procedures that involve breaking stones with a laser and then attempting to retrieve the pieces with a small basket, the CVAC System offers an integrated solution. The single, steerable device combines direct visualization, laser lithotripsy, microjet irrigation, and active vacuum aspiration. As the laser pulverizes the stone, the system simultaneously and continuously suctions the fragments out of the kidney.

This unique mechanism not only ensures a more complete cleaning but also enhances safety. A critical concern during ureteroscopy is the buildup of pressure within the kidney, which can lead to complications. By providing continuous fluid outflow through a dedicated channel, the CVAC System is designed to maintain safe, low intrarenal pressure throughout the procedure.

“These data demonstrate that the safety and efficacy of the second-generation CVAC System are consistent with the first-generation platform, while delivering meaningful improvements in procedural efficiency,” noted Brian Eisner, M.D., Chair of Urology at Tulane University School of Medicine and lead author on the CLEARANCE publication. He added that the findings “support its role as a standard of care for kidney stone removal across a broad range of stone burdens.”

A Path Forward Paved with Promise and Precaution

The prospect of a "one-and-done" treatment that minimizes long-term suffering has generated significant optimism among urologists. The ability to effectively clear large stone burdens in a single, minimally invasive session offers a compelling alternative to more invasive surgeries like percutaneous nephrolithotomy (PCNL).

However, the rollout of this advanced technology has not been without challenges. In February 2025, Calyxo issued an "Urgent Device Field Correction" notice for the CVAC System. The alert identified a newly discovered risk when the device is used in patients with high-viscosity (thick) fluid in their kidneys. In such cases, the system's outflow could be impeded, leading to a dangerous buildup of intrarenal pressure that could result in serious injury. At the time of the notice, one patient death had been reported in relation to this issue.

In response, the company issued updated instructions, advising physicians to immediately stop fluid inflow if outflow appears slow or absent and to avoid using the system if visibility is obscured by opaque fluid. This incident underscores that, like any powerful medical tool, the CVAC System's optimal performance and safety depend on proper training and careful patient selection.

The compelling long-term data offers a clear vision for a future with fewer complications from kidney stones. Yet, the safety advisory serves as a critical reminder of the diligence required as the medical community weighs the device's immense potential against the nuances of its real-world application.