Nov 9, 2026 · @Yoon Hang Kim MD

Yoon Hang Kim MD Board-Certified in Preventive Medicine | Integrative & Functional Medicine Physician

About Dr. Kim Dr. Yoon Hang Kim is a board-certified physician with over 20 years of clinical experience in integrative and functional medicine. A graduate of the University of Arizona Center for Integrative Medicine's Osher Fellowship under Dr. Andrew Weil, he holds certifications in preventive medicine, medical acupuncture, and integrative and holistic care. Dr. Kim specializes in low dose naltrexone (LDN) therapy, autoimmune conditions, chronic pain, integrative oncology, fibromyalgia, chronic fatigue syndrome, mast cell activation syndrome, and mold toxicity. He is the author of eight books — including MCAS: Epidemic in Plain Sight and LDN Primer — and has published more than 25 peer-reviewed articles. Professional: www.yoonhangkim.com | Clinical: www.directintegrativecare.com

⚠️ Important: This article is for educational purposes only and does not constitute medical advice, diagnosis, or treatment. The information presented here reflects published research and publicly available professional biographies as of the date of publication. Always consult your own healthcare provider before making clinical decisions. Dr. Kim has no financial relationship with MIPS or Dr. Spencer.

Introduction: When Mast Cells, Veins, and Dysautonomia Collide

If you live with mast cell activation syndrome, you already know that MCAS rarely travels alone. Postural orthostatic tachycardia syndrome (POTS), Ehlers-Danlos syndrome (EDS), chronic pelvic pain, and debilitating fatigue often show up together — a clinical overlap so common that many practitioners now refer to it informally as "the triad" or "the pentad" depending on how many co-travelers a given client carries.

What gets less attention is the vascular piece of the puzzle. Pelvic venous disease — compression or obstruction of the iliac veins, incompetent ovarian veins, and related structural abnormalities — can quietly drive or worsen symptoms that look and feel identical to MCAS flares, POTS episodes, and chronic pelvic pain. Until recently, these vascular contributors were rarely evaluated in the MCAS population.

That is starting to change, in large part because of the clinical and research work coming out of one center in Colorado: Minimally Invasive Procedure Specialists (MIPS), led by interventional radiologist Dr. Elizabeth "Brooke" Spencer.

This article explores what MIPS does, what their published research actually shows, and how their approach fits into the broader care of clients living with MCAS and its overlapping conditions.

Who Is Dr. Brooke Spencer?

Dr. Elizabeth "Brooke" Spencer, MD, FSIR, is the medical director and CEO of Minimally Invasive Procedure Specialists (MIPS) in Highlands Ranch, Colorado. She is not an allergist-immunologist or a mast cell specialist in the traditional sense. She is an interventional radiologist — and a highly accomplished one — whose clinical focus sits squarely on complex venous disease.

Her training tells the story:

• Medical degree (1995): University of Vermont
• Diagnostic radiology residency (2000): Duke University
• Interventional radiology fellowship (2001): Mallinckrodt Institute of Radiology, Washington University in St. Louis
• Board certification: Vascular and Interventional Radiology, American Board of Radiology
• Fellowship designation: Fellow of the Society of Interventional Radiology (FSIR)

Her professional biography describes extensive hands-on experience in reopening obstructed deep veins, treating pelvic venous disease, and managing superficial venous disorders. This is important context: Dr. Spencer's connection to the MCAS world is not that she manages mast cell mediators or prescribes cromolyn. Her connection is that she treats the vascular pathology that may be silently contributing to the symptom burden many MCAS clients carry — especially those with concurrent POTS.

What MIPS Does Best: Pelvic Venous Interventions

MIPS is not trying to be everything to everyone. What they do — and do well — is identify and treat structural venous problems that standard imaging frequently misses. Their core interventions include:

Iliac vein stenting for clinically significant venous obstruction or compression, including May-Thurner syndrome — a condition where the left common iliac vein is compressed by the overlying right common iliac artery. This is far more common than most clinicians realize, and it can produce pelvic pain, lower extremity swelling, and hemodynamic changes that fuel orthostatic intolerance.

Ovarian and gonadal vein embolization for incompetent veins with pathologic reflux — backward flow that contributes to pelvic congestion, pain, and vascular instability.

Sclerotherapy for selected abnormal veins when indicated.

What makes MIPS distinctive in the MCAS and POTS space is not the procedures themselves — other interventional radiology practices perform these. The distinction is that Dr. Spencer and her team actively evaluate for these vascular contributors in clients who already carry multisystem diagnoses like POTS, EDS, MCAS, and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Their website explicitly lists these conditions as frequently co-occurring with — and potentially caused by — pelvic venous disease.

That last phrase deserves a measured read. "Potentially caused by" is a practice-level clinical claim, not an established causal relationship across all of these conditions. The published research, which we will examine next, supports it most strongly for POTS and orthostatic intolerance — not for MCAS itself.

The POTS–Pelvic Venous Disease Connection: What the 2026 Research Shows

The strongest evidence for MIPS's approach comes from a 2026 publication: "Association and post-iliac vein stenting symptom improvement of postural orthostatic tachycardia syndrome and orthostatic intolerance with pelvic venous disorders: two retrospective studies."

This paper examined two related datasets:

1. An Emory University cardiology population of clients with POTS and orthostatic intolerance, evaluated for concurrent pelvic venous disorders and the diagnostic performance of different imaging modalities.
2. A MIPS clinical population of 271 female clients with POTS or orthostatic intolerance who underwent iliac vein stenting between June 2019 and November 2024. The two study populations partially overlapped.

The key findings were clinically meaningful:

• Clients who received iliac vein stenting reported significant quality-of-life improvements.
• Standard imaging — ultrasound, CT, and MRI — frequently missed pelvic venous disease. The investigators concluded that these modalities may not adequately exclude pelvic venous pathology without expert clinical review.

These results are encouraging, and they point to a real, underrecognized contributor to dysautonomia symptoms. But as with all good science, context matters.

What the study does well:

• It draws on a substantial clinical sample (271 clients).
• It highlights a genuine diagnostic gap — pelvic venous disease is frequently missed on routine imaging.
• It reports patient-centered outcomes (quality of life), not just hemodynamic measurements.

What the study cannot tell us — yet:

• These were retrospective studies, not randomized controlled trials. Selection bias is inherent in the design.
• The treated population was entirely female, which limits generalizability.
• Improvement after stenting does not isolate the specific contribution of the procedure from other concurrent treatments, placebo response, or natural disease trajectory.
• The authors themselves acknowledged the need for additional prospective trials to examine both clinical and hemodynamic effects.

The honest interpretation: pelvic venous disease appears to be a treatable contributor in a meaningful subset of clients with POTS. That is a legitimate and clinically important finding. It is not the same as saying iliac stenting is an established treatment for all POTS — and it says even less about MCAS directly.

Where MCAS Fits In — And Where It Doesn't

Here is where we need to be precise, because precision is how we protect our clients from both overtreatment and missed opportunities.

MCAS is defined by three consensus criteria:

1. Recurrent, episodic symptoms consistent with mast cell mediator release affecting two or more organ systems.
2. Objective laboratory evidence of mast cell mediator elevation during a symptomatic episode compared with baseline.
3. Clinical improvement with medications that target mast cell mediators or their effects.

That diagnostic framework is biochemical and immunological. It has nothing to do with venous hemodynamics.

So when MIPS lists MCAS among conditions associated with pelvic venous disease, the question becomes: associated how? The most plausible clinical connection runs through POTS and shared symptom burden, not through direct mast cell biology. Many clients with MCAS also have POTS. Many clients with POTS have unrecognized pelvic venous compression. When you treat the venous compression, the POTS improves — and when POTS improves, the overall symptom load drops, which can look and feel like an improvement in MCAS as well.

That is a clinically meaningful chain. But it is an indirect one. Stenting a compressed iliac vein does not reduce tryptase levels. It does not stabilize mast cell membranes. What it may do is reduce the hemodynamic stress that triggers autonomic dysregulation, which in turn may reduce the physiological triggers that provoke mast cell degranulation in susceptible individuals.

This is the kind of nuance that matters enormously in clinical practice — and it is exactly the kind of nuance that gets lost when a center is described simply as an "MCAS treatment center." MIPS is not treating MCAS. MIPS is treating a vascular contributor to the symptom complex that many MCAS clients carry. That is a different thing, and it is worth understanding clearly.

Clinical Pearl: Questions to Ask Before Referral

If you are a clinician considering a referral to MIPS — or a client considering a consultation — the following questions can help clarify expectations and maximize the value of the visit:

"Do you evaluate MCAS itself, or do you evaluate venous disease in clients who also have MCAS?" This is the single most important framing question. It sets the scope of what the consultation will and will not address.

"What symptoms and objective findings would make venous intervention appropriate in my case?" Not every client with POTS has pelvic venous compression, and not every compression requires intervention. Understanding the clinical threshold matters.

"Which expected benefits relate to pelvic pain, which to orthostatic intolerance, and which — if any — to documented MCAS?" This forces specificity. A client who expects mast cell stabilization from a vein stent will be disappointed. A client who understands that the stent targets hemodynamic stress can set realistic expectations.

"What are your complication rates, reintervention rates, and long-term follow-up outcomes for clients with my profile?" Any interventional procedure carries risk. Informed consent requires knowing the numbers, not just the success stories.

"If a procedure is recommended, how will you coordinate with my allergist-immunologist and autonomic specialist?" MCAS and POTS clients typically have multiple specialists. Siloed care is dangerous care. Coordination should be the rule, not the exception.

Contact Information: MIPS is located at 8671 South Quebec Street, Suites 130 and 200, Highlands Ranch, CO 80130. Appointments can be scheduled by calling 303-805-7477.

Work with Dr. Kim

Dr. Kim provides integrative and functional medicine consultations for clients navigating MCAS, POTS, chronic pain, autoimmune conditions, and complex multisystem disease. His practice, www.directintegrativecare.com, is a membership-based telemedicine model available in Iowa, Illinois, Missouri, Georgia, Florida, and Texas — no insurance hassles, no rushed visits, and a physician who actually understands the conditions you are dealing with.

For professional consulting, speaking engagements, and mentorship inquiries: www.yoonhangkim.com

References

1. Spencer EB, et al. Association and post-iliac vein stenting symptom improvement of postural orthostatic tachycardia syndrome and orthostatic intolerance with pelvic venous disorders: two retrospective studies. eClinicalMedicine. 2026;92:103772. doi:10.1016/j.eclinm.2026.103772
2. Pelling MM, Brown MT, Gilliland CA, Cutchins A. Left common iliac vein stenting in a case of postural orthostatic tachycardia syndrome/pelvic pain overlap. Cureus. 2024;16(2):e53974. doi:10.7759/cureus.53974
3. Valent P, Akin C, Bonadonna P, et al. Proposed diagnostic algorithm for patients with suspected mast cell activation syndrome. J Allergy Clin Immunol Pract. 2019;7(4):1125-1133.e1. doi:10.1016/j.jaip.2019.01.006
4. Afrin LB, Self S, Menk J, Lazarchick J. Characterization of mast cell activation syndrome. Am J Med Sci. 2017;353(3):207-215. doi:10.1016/j.amjms.2016.12.013
5. Minimally Invasive Procedure Specialists (MIPS). Professional biography and services. Accessed November 2026. https://myveindr.com

Dr. Yoon Hang Kim is the author of MCAS: Epidemic in Plain Sight and LDN Primer*, both available on Amazon, and is the founder of the LDN Support Group. For clinical consultations, visit www.directintegrativecare.com. For professional inquiries, visit www.yoonhangkim.com.*