The novel coil procedure was led by David Santiago-Dieppa, MD, a cerebrovascular and endovascular neurosurgeon at UC San Diego Health and associate professor of neurological surgery at the University of California San Diego School of Medicine. According to Santiago-Dieppa, chronic subdural hematoma is an increasingly common condition in neurosurgical practice, and patients stand to benefit from minimally invasive approaches that can reduce the need for repeat operations. The first patient treated with the new coil technology at UC San Diego Health is recovering well, an encouraging early signal as clinicians continue to evaluate the device’s potential. He emphasized that advances in both coil-based and liquid embolization technologies are giving physicians more options to tailor treatment to each patient’s anatomy and clinical needs, with the ultimate goal of more consistently treating the source of these brain bleeds and improving outcomes.

Chronic subdural hematoma develops when blood collects between the brain and its outermost covering, the dura mater, often following a minor head injury that may have seemed trivial at the time. Because the bleeding accumulates slowly over days or weeks, symptoms such as headaches, confusion, memory problems, gait difficulties, and drowsiness can emerge gradually and are sometimes mistaken for normal aging or dementia. The condition is becoming steadily more common for two converging reasons: the population is growing older, and a rising number of people take blood-thinning medications such as anticoagulants and antiplatelet drugs, which impair the body’s ability to stop even small bleeds. That demographic and pharmacological trajectory is what drives the projection that chronic subdural hematoma may top the list of adult cranial neurosurgical conditions within the decade.

For much of modern neurosurgical history, the standard treatment was surgical drainage, in which a surgeon drills one or more small holes in the skull to evacuate the accumulated blood. While often effective, surgery carries risks for elderly patients and, crucially, does not address the underlying vascular source that can allow fluid and blood to reaccumulate. Recurrence rates after drainage alone have historically been a persistent clinical challenge, forcing a subset of patients back to the operating room for repeat procedures that compound their risk and prolong recovery.

In recent years, a minimally invasive alternative called middle meningeal artery embolization has transformed the treatment landscape. The middle meningeal artery, or MMA, is a branch of the external carotid artery that supplies the dura mater and is intimately involved in the formation and persistence of chronic subdural hematomas. During embolization, physicians navigate a tiny microcatheter through the vasculature, typically from an access point in the groin or wrist, until it reaches the MMA. They then deploy an embolic material to block the artery, cutting off the blood supply that feeds the bleed and helping prevent it from returning. Rather than replacing surgery in every case, embolization is often combined with drainage or used in select patients as a stand-alone strategy, and studies have shown it can reduce the likelihood that patients will need additional procedures while potentially improving long-term outcomes.

As MMA embolization has gained widespread adoption, device developers have raced to improve how physicians seal the target artery. Two broad technological philosophies have emerged. Coil-based approaches use specialized metallic coils to mechanically obstruct blood flow within the vessel, while liquid embolic materials are designed to flow with the bloodstream and penetrate smaller vessel branches farther from the treatment site, occluding a more diffuse vascular network. Each strategy has trade-offs related to vessel anatomy, procedural control, and the completeness of closure. The newly introduced coil technology adopted at UC San Diego Health is engineered to help physicians shut down the artery more completely and efficiently than previous generations of embolization coils. Its flexible design allows delivery through small and tortuous blood vessels, and it can treat a longer section of the artery than earlier coils, potentially reducing the number of devices and steps required in a given procedure.

Santiago-Dieppa’s role in the technology extended beyond the operating room. Drawing on extensive experience performing MMA embolization procedures, he provided clinical insights during the device’s development phase, helping shape a tool intended to improve procedural efficiency and the quality of artery closure. That clinician-inventor feedback loop, in which frontline operators inform device design before and after regulatory approval, has become an increasingly important pathway for translating neurovascular innovations into routine practice. It also reflects a broader trend in which academic medical centers serve simultaneously as early adopters, evaluators, and co-developers of emerging technologies.

UC San Diego Health’s leadership in this field is not limited to device adoption. Researchers in the Department of Neurological Surgery at UC San Diego School of Medicine developed the Patency After Coil Embolization, or PACE, scoring system, a standardized method for measuring how completely blood flow through the middle meningeal artery has been eliminated after treatment. The system gives clinicians and researchers a common language for grading technical success, and early research suggests that more complete closure of the artery may be linked to better resolution of the brain bleed over time. By quantifying the degree of occlusion achieved with different devices and techniques, tools like the PACE score help determine which patients benefit most from which embolization strategy, moving the field toward evidence-based personalization.

The institution has also been deeply involved in the clinical trial infrastructure supporting liquid embolic agents. J. Scott Pannell, MD, director of neurointerventional surgery, endovascular neurosurgeon, and neurointerventional radiologist at UC San Diego Health, and professor of neurological surgery and radiology at UC San Diego School of Medicine, served as a site investigator for the EMBOLISE clinical trial, which evaluated the addition of MMA embolization to standard treatment for chronic subdural hematoma. Evidence from that national trial and others supported the recent FDA approval of a liquid embolic for this indication, and Pannell’s involvement helped bring new embolization techniques and clinical research opportunities to patients in San Diego. He noted that the growing body of evidence supporting MMA embolization has fundamentally changed how physicians approach the condition, and that liquid embolic technologies offer a primary option that may allow more complete treatment in select patients. In his view, participation in trials such as EMBOLISE has been critical to understanding how these therapies can improve patient outcomes.

The convergence of these developments, from next-generation coils to approved liquid embolics and standardized occlusion scoring, points toward a future in which chronic subdural hematoma treatment becomes more predictable, effective, and accessible for the growing number of patients diagnosed each year. Physicians can now select among mechanical and liquid occlusion strategies based on vascular anatomy, the extent of dural supply, and patient-specific risk factors, rather than relying on a one-size-fits-all surgical approach. UC San Diego Health, nationally recognized for its treatment of complex brain, spine, and cerebrovascular disorders and ranked among the nation’s best in neurology and neurosurgery in the 2026-2027 U.S. News Best Hospitals rankings, continues to advance this evolution through research, clinical trials, and multidisciplinary care for conditions ranging from stroke and aneurysms to traumatic brain injury. As the population ages and anticoagulant use rises, the ability to treat the vascular source of chronic brain bleeds through a catheter rather than a craniotomy may prove to be one of the most consequential shifts in neurosurgery this decade.

Subject of Research: Minimally invasive middle meningeal artery embolization technologies for chronic subdural hematoma

Article Title: First health system on West Coast to use new brain bleed technologies

Article References: First health system on West Coast to use new brain bleed technologies. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: chronic subdural hematoma, middle meningeal artery embolization, neurosurgery, embolization coils, liquid embolic, UC San Diego Health, EMBOLISE trial, PACE score, minimally invasive procedures, brain bleed, neurointerventional surgery, aging population

The team, led by Florian Nima Fleckenstein and Federico Collettini of the Department of Diagnostic and Interventional Radiology at Charité Universitätsmedizin Berlin, turned to transarterial embolization, a minimally invasive technique in which physicians thread catheters through the arterial system and deliberately plug the vessels feeding a bleeding site. The breast is an anatomically treacherous territory for this kind of emergency. Roughly sixty percent of its blood supply arrives through perforating branches of the internal mammary artery, also called the internal thoracic artery, which runs along the inside of the chest wall. The remaining forty percent comes from perforators of the thoracoacromial and lateral thoracic arteries and from terminal branches of the third to eighth intercostal arteries. This complex, multifocal supply means that a bleeding breast tumor can drain blood at alarming speed. The internal mammary artery alone can carry flow rates of up to about 63 milliliters per minute, enough to produce a life-threatening loss of blood within minutes.

On admission, the patient underwent a contrast-enhanced computed tomography scan, which revealed the enormous exophytic mass with extensive invasion of the pectoral muscle and multiple prominent feeding arteries arising from the left internal mammary artery, the superior thoracic artery, the thoracoacromial artery and the lateral thoracic artery. Notably, the scan showed no active contrast extravasation, meaning no vessel was visibly spurting contrast dye at that moment, and no pseudoaneurysm or significant tumor blush appeared on subsequent digital subtraction angiography. In many clinical settings the absence of a visible bleeding point would argue against embolization. Here, the interdisciplinary team of gynecologists, anesthesiologists and interventional radiologists decided to embolize empirically, occluding every identified tumor-feeding artery because the macroscopic bleeding from the ulcerated tumor was extensive and initial attempts at tamponade, pressing to compress the bleeding surface, had failed.

The first procedure was technically elegant. Through a 2.5 French hydrophilic microcatheter, small enough to navigate deep into the arterial tree, the team delivered two detachable-style Hilal microcoils and polyvinyl alcohol particles measuring 355 to 500 micrometers. The two agents serve complementary purposes. Coils provide a mechanical scaffold that blocks larger vessels outright, while the microscopic PVA particles travel further downstream, lodging in the small vessels inside the tumor to reduce arterial pressure within the tissue. The post-embolization angiogram confirmed complete occlusion of the feeding arteries while preserving flow in the parent subclavian artery, and coils were placed in the distal internal mammary artery specifically to prevent blood from sneaking backward into the treated segment, a phenomenon known as retrograde recanalization. The visible bleeding stopped, and the patient was transferred to the intensive care unit.

Within twelve hours she received palliative radiation therapy to the left breast, intended to shrink the tumor and reduce further bleeding risk. But forty-eight hours after the first embolization, the hemorrhage returned with full force, again dropping her blood pressure and threatening her life. Repeat imaging told a story that illustrates why these cases are so difficult. The left internal mammary artery had partially reopened, and multiple previously silent feeding arteries had sprung into action, arising from the left subclavian artery and the fifth intercostal artery on the same side. The tumor’s vascular network had effectively rerouted itself around the blockages.

The second procedure escalated the arsenal. The team again used particles and coils, but this time added a liquid embolic agent, Histoacryl, a cyanoacrylate glue that solidifies on contact with blood and can be pushed into vessels too small or too fast for solid agents to capture. They continued until there was complete stasis, a full stoppage of flow, in the target vessels. Yet bleeding persisted from the medial portion of the tumor. That detail prompted a crucial diagnostic insight: because the internal mammary arteries run bilaterally on both sides of the sternum and are connected through a network of collateral channels, the tumor could be fed from the opposite side of the chest. Catheterizing the right internal mammary artery with a dedicated internal mammary catheter revealed multiple collateral feeding arteries crossing over to supply the left thoracic wall and tumor. Embolizing the right-sided vessels with the same liquid embolic finally stopped the bleeding completely.

The team also systematically excluded other potential supply routes, catheterizing both inferior epigastric arteries in the abdomen to check whether the tumor drew blood from below the chest. They found no extravasation and no tumor-related vascularization there. In the days and weeks that followed, no further bleeding episodes occurred, and despite the aggressive bilateral embolization, no skin necrosis developed, a reassuring sign that the chest wall tissue tolerated the loss of its embolized vessels. The patient ultimately died four weeks later from liver failure caused by extensive hepatic metastases, underscoring that the procedure was palliative throughout: it controlled a catastrophic symptom but could not alter the underlying cancer.

The authors dissect three mechanisms that likely explain the recurrent hemorrhage, and their analysis carries lessons for any center managing similar emergencies. First, they invoke a phenomenon recognized in trauma surgery, in which injured internal mammary arteries retract into the partially contracted pectoralis muscle. Initial hemostasis may occur because of arterial spasm and low blood pressure, and when the muscle relaxes and the spasm resolves, delayed bleeding can erupt. In this case, emergency radiation therapy causing tumor necrosis may have further released tissue pressure that had been tamponading the bleeding vessels. Second, the sheer complexity of tumor vascularity means smaller collaterals can open after embolization, particularly from the contralateral internal mammary artery and the intercostal arteries, a mechanism the authors concede interventional radiology cannot fully anticipate before it manifests. Third, the reopening of the left internal mammary artery may have reflected incomplete embolization with coils and particles, and might have been prevented by using liquid embolics more aggressively from the start. They note, however, that the rationale for particles is deeper penetration into the tumor’s vascular bed to lower arterial pressure within the tissue, an advantage especially when no discrete arterial bleeding point is visible on imaging.

Life-threatening hemorrhage from locally advanced, fungating breast cancer is rare, which is precisely why the evidence base is thin and management guidelines are scarce. Surgical options are often limited when a tumor has invaded the chest wall, and patients in this condition are frequently too unstable for major operations. The Berlin case, along with the handful of previously reported instances of particle embolization and transcatheter embolization for recurrent locally advanced breast cancer, suggests that interventional radiology can fill this gap, buying time and comfort for patients in otherwise desperate straits. The authors emphasize that success depended on effective interdisciplinary planning among gynecologists, anesthesiologists and radiologists, and their central message is sober but practical: transcatheter arterial embolization is a rapid and effective way to stabilize these patients and facilitate further treatment, but the complexity of tumor blood supply means clinicians should expect recurrent hemorrhage and be prepared for aggressive, repeated procedures rather than assuming a single session will suffice.

Subject of Research: Repeated emergency transarterial embolization to control life-threatening hemorrhage from ulcerating locally advanced breast carcinoma

Article Title: Repeated emergency embolization for life-threatening bleeding from ulcerating breast carcinoma: a case report

Article References: Fleckenstein, F. N., Pietzner, K., Gebauer, B., & Collettini, F. (2025). Repeated emergency embolization for life-threatening bleeding from ulcerating breast carcinoma: a case report. CVIR Oncology, 1(1), Article 9. https://doi.org/10.1007/s44343-025-00009-z

Image Credits: AI Generated

DOI: 10.1007/s44343-025-00009-z

Keywords: breast cancer, hemorrhage, transarterial embolization, interventional radiology, locally advanced tumor, internal mammary artery, liquid embolic, case report, tumor vascularity, palliative care, Repeated, emergency