SinglePass has published a multicenter retrospective study of its Kronos biopsy-tract electrocautery technology in which all 120 consecutive procedures achieved technical tract closure and no clinically significant post-procedure bleeding events were identified during 30 days of follow-up. The patients underwent coaxial core needle biopsy of organs or masses including the liver, kidney, abdomen or mesentery and lung, after which the biopsy pathway was treated with electrocautery while the device was withdrawn. The study, published in the Journal of Vascular and Interventional Radiology, provides encouraging real-world evidence for an FDA-cleared technology intended to achieve hemostasis after percutaneous biopsy, but its retrospective noncomparative design means it cannot establish how much the device reduces bleeding versus standard care.
The numerical outcome is nevertheless striking because biopsy-tract hemorrhage remains one of the important complications of percutaneous tissue sampling, particularly when highly vascular organs are targeted or patients have factors that increase bleeding risk. Among the 120 patients, 74 underwent liver biopsies, 28 kidney biopsies, 10 abdominal or mesenteric procedures, five lung biopsies and three procedures involving other targets. Four small hematomas were observed during procedures, but the published abstract reports that they did not progress after electrocautery, and there were no subsequent bleeding interventions, transfusions, surgeries or bleeding-related readmissions through 30 days.
Why can a biopsy continue bleeding after the tissue sample has already been collected?
A percutaneous core biopsy requires a needle to travel through skin, soft tissue and often solid organ parenchyma before reaching the target. Even when the biopsy specimen itself is obtained without difficulty, that needle leaves a physical tract behind. Small blood vessels crossed along the route can continue to bleed after the needle is removed, and blood may accumulate internally where it is not immediately visible.
Most biopsies are completed safely with observation and natural clotting, but bleeding risk increases with certain organs, larger needles, coagulopathy, antithrombotic therapy and other clinical factors. Interventional radiologists can use several approaches to control tract bleeding, including gelatin-based material, coils or other embolic methods depending on the procedure. SinglePass is proposing a different approach: thermally coagulating tissue along the tract so hemostasis occurs mechanically as the device is withdrawn.
How does the Kronos electrocautery system work?
The FDA cleared the Kronos Electrocautery Device under 510(k) K232805 in April 2024 as a Class II electrosurgical cutting and coagulation accessory. The technology is designed to achieve hemostasis by coagulating soft tissue following percutaneous biopsy.
A newer SinglePass SP20 configuration received FDA clearance in February 2026. The FDA summary describes it as a single-use, battery-powered electrocautery instrument with a stainless-steel probe and a heated distal segment. A feedback system maintains an operating temperature of approximately 75 to 100 degrees Celsius while the clinician advances or withdraws the probe through the biopsy tract. Its labeled application covers soft tissue in the liver, kidney and lung following percutaneous biopsy.
That design is operationally appealing because it attempts to close the route immediately rather than waiting for bleeding to become clinically apparent and then treating the complication. Whether routine prophylactic cauterization is economically and clinically preferable to selective use in high-risk biopsies will require more comparative evidence.
Who were the 120 patients in the published study?
The study included 120 consecutive patients with a mean age of 62 years, and the sex distribution was almost even. Liver procedures accounted for 61.7% of the cohort, kidney biopsies for 23.3%, abdominal or mesenteric targets for 8.3%, lung procedures for 4.2% and other targets for the remainder. Common indications included liver masses, medical liver disease and medical renal disease.
Twenty-one patients, or 17.5%, were taking antithrombotic therapy, which was held according to Society of Interventional Radiology guidance. Slightly more than half of procedures were performed with ultrasound guidance and the remainder with CT. The authors reported an average procedure duration of approximately 17 minutes, while outpatients were discharged after an average observation period of roughly 2.8 hours.
These characteristics suggest the cohort included routine solid-organ biopsy practice rather than only an exceptionally high-risk bleeding population. That makes the zero clinically significant bleeding result interesting, but it also means the expected bleeding rate without the device may have been relatively low.
What happened to the four hematomas observed during biopsy?
Four small intraprocedural hematomas developed but did not progress after electrocautery tract treatment. Through the 30-day follow-up period, investigators reported no clinically significant bleeding, blood transfusions, additional interventional procedures, surgery or bleeding-related hospital returns. In a subgroup of 65 patients with available laboratory comparisons, none experienced a hemoglobin decline greater than 1.5 g/dL attributable to post-biopsy bleeding.
No procedure-related deaths were reported. Five patients died while in hospice during the follow-up period, but the study investigators did not attribute those deaths to the biopsy or tract-closure procedure. These details matter because simply reporting “zero bleeding” without describing follow-up could obscure delayed complications. The 30-day assessment provides more meaningful reassurance than a result limited to the first hour after biopsy.
Does zero bleeding in 120 patients prove Kronos prevents biopsy hemorrhage?
No. This is the most important limitation of the study. There was no contemporary control group undergoing comparable biopsies without Kronos, so researchers cannot calculate a relative reduction in bleeding attributable to the device. A zero-event rate may reflect device performance, careful patient selection, skilled operators, appropriate management of blood-thinning medicines, the baseline safety of modern image-guided biopsy or some combination of those factors.
Retrospective studies are also vulnerable to differences in documentation and patient follow-up. Investigators can review medical records for clinically apparent events, but subtle outcomes may be captured less consistently than in a prospective protocol requiring standardized imaging and laboratory testing for every participant.
The publication therefore supports feasibility and an absence of an obvious safety signal. It does not yet prove that routine tract cauterization is superior to standard biopsy management or that every biopsy patient should receive the device.
What type of study would provide stronger evidence?
A prospective controlled trial could randomize similar patients to Kronos-assisted tract closure or standard management and use prespecified definitions for bleeding, transfusion, hemoglobin decline, additional procedures and hospital observation. Stratification by organ and baseline bleeding risk would be especially useful because a renal biopsy, liver tumor biopsy and lung biopsy do not carry identical complication profiles.
A larger high-risk population would also clarify where the technology creates the greatest value. If post-biopsy hemorrhage is already extremely uncommon in low-risk patients, prophylactically treating everyone may offer limited incremental benefit. Conversely, demonstrating a meaningful reduction among patients with vascular lesions, difficult organ anatomy or elevated bleeding risk could support a clearer targeted use case.
Why could a battery-powered single-use system matter to interventional radiologists?
Procedure-room simplicity is often commercially important for devices intended to be added to an existing workflow. A single-use battery-powered cautery system does not require a large external electrosurgical generator to perform its tract-hemostasis function, potentially reducing setup and allowing the device to be deployed where image-guided biopsies are already taking place.
The technology is also designed to fit directly into the end of the biopsy procedure rather than requiring an entirely separate intervention. Once the tissue sample has been obtained, the operator can treat the access tract during withdrawal. That could be attractive if the device demonstrably reduces complications or observation requirements without materially extending procedure time.
Commercial success, however, will depend on reimbursement, device cost and proof that avoiding a small number of bleeding complications offsets routine use. Clinical enthusiasm for a mechanically elegant solution does not automatically translate into economical adoption.
How should hospitals interpret the 100% technical success result?
Technical success indicates that operators were able to use the device as intended across all included cases. That is valuable for assessing usability and feasibility, particularly when a new device must function across different imaging modalities and target organs. It does not mean all biopsies were clinically perfect, nor does it establish comparative efficacy.
The more meaningful clinical observation is the absence of major bleeding events during follow-up, but that finding needs a denominator and comparator before hospitals can estimate how many complications would actually be prevented. The next stage of evidence should therefore move from “can this safely close biopsy tracts?” toward “which patients benefit enough to justify using it routinely?”
SinglePass now has FDA-cleared hardware and a published multicenter dataset supporting real-world feasibility. What it does not yet have is definitive evidence quantifying superiority over conventional tract management. That gap makes the study encouraging rather than conclusive, and it gives the company a clear clinical-development question for its next prospective trial.