Interventional radiology is known for being one of the most challenging specialties for coders and auditors. Coding correctly for embolization procedures can be particularly tricky due to the multiple coding considerations involved. This article delves into the specifics of coding for middle meningeal artery embolization (MMAE), the procedure itself, and its clinical applications, especially in the treatment of chronic subdural hematomas (cSDH).
Arteries of the Meninges
Coding for Middle Meningeal Artery Embolization (MMAE)
What is the correct code to bill for the embolization of middle meningeal artery (MMA)? Is it CPT code 61624 or 61626 since the MMA is part of the external carotid artery (ECA)?
For this procedure, selective catheter placements and angiograms were done on the bilateral common carotid arteries (intracranial), bilateral ECAs and bilateral MMAs, along with the embolization. The coder might consider using codes 36222-50, 36227-50, 75894, and 75898 and be unsure whether to assign the 61626 or the 61624.
The pathology being treated is CNS (brain tumor called meningioma), so 61624 applies. If for subdural bleeding next to the brain (in the CNS) via the MMA, we would still report 61624. Remember, it is not the vessel you are embolizing, but the pathology you are treating, when it comes to the embolization code, however the catheter placement is based on catheter tip location.
CPT code 61624 is defined as "Transcatheter permanent occlusion or embolization (eg, for tumor destruction, to achieve hemostasis, to occlude a vascular malformation), percutaneous, any method; central nervous system (intracranial, spinal cord)."
There is no separate code for the radiological supervision and interpretation component of the procedure with all road mapping and intraprocedural guidance (75894) and completion angiography (75898) being included with the surgical code. All other components of the embolization procedure may be coded separately.
Understanding Embolization Procedures
Embolization is the therapeutic introduction of various substances into the circulation to occlude vessels. The goals of embolization may be adjunctive, curative, or palliative.
Note: A prophylactic embolization is when the physician opts to occlude a different vessel from the one that is the target of the planned intervention. The most common example is when prior to treatment of a liver tumor (37243), the gastric artery or gastroduodenal artery may be embolized prior to treating the liver tumor. In these instances, code 37242 is assigned rather than 37243.
The number of vessels treated does not determine the number of embolization codes assigned, rather the number of organs being treated determines the number of embolization codes assigned.
Clinical Applications of MMAE
MMAE has emerged as an effective, minimally invasive treatment for chronic subdural hematomas (cSDH). The pathological cause of cSDH is hypothesized to result from elevated angiogenic factors due to chronic dural injury and inflammation. This results in thin and fragile capillaries along the subdural outer membrane of the hematoma, which captures its blood supply from the middle meningeal artery (MMA).
Middle Meningeal Artery Embolization
Study on MMAE for cSDH Treatment
A study querying all MMAE cases up to October 7th, 2020, from the TriNetX Analytics Network, included 191 patients (mean age: 71.2 ± 13.5, 73.3% male, 69.6% White, 13.6% Black/African American, and 16.8% other). Essential hypertension (71.3%), heart disease (62.8%), type 2 diabetes mellitus (27.2%), nicotine dependence (23.6%), chronic kidney disease (19.4%), and overweight/obesity (19.4%) were among the most prevalent comorbidities.
At presentation, 20.4% and 40.3% were on antiplatelet and anticoagulation therapy, respectively. The study reinforces that MMAE is a safe and effective minimally invasive procedure for the treatment of cSDH.
Inclusion and Exclusion Criteria
- Inclusion Criteria: Confirmed diagnosis of nontraumatic chronic subdural hemorrhage (ICD I62.03) and nontraumatic subdural hemorrhage (ICD I62.00) who had one of the following Current Procedural Terminology (CPT) codes 61624 or 61626 for transcatheter permanent occlusion or embolization within one month of the cSDH diagnosis.
- Exclusion Criteria: Patients younger than 18 years old, patients who had a diagnosis of cerebral AVM (ICD Q28.2), malignant neoplasm of the brain (ICD C71), malignant neoplasm of the head, face, and neck (ICD C76.0), epistaxis (ICD R04.0), and cerebral aneurysm/acquired cerebral arteriovenous fistula (ICD I67.1) because the embolization could be for a separate indication.
Clinical Outcomes of MMAE
Clinical outcomes from the study are presented in Table 3 (below). The 180-day mortality for the study was 6.3% in the MMAE cohort; however, the mortality of the control group when propensity-matched for baseline characteristics and comorbidities was 0.52-5.2% (1-10 patients), signifying that the true mortality rate for our cohort is between 1.0-5.8%% rather than 6.3%.
The survival probability at the end of the time window (i.e., 180 days) was 92.3% and 96.7% for the MMAE and control cohorts, respectively (p-value=0.063). Additionally, Figure 4 demonstrates CCI measured for patients in the MMAE cohort. The mean CCI was 7.6 (95% CI: 4.8-10.3), 8.5 (95% CI: 2.1-14.9), and 3.6 (95%: CI 3.2-4.1) for patients that died within 6 months, 6 months-5 years, and those still alive post-MMAE, respectively.
With the cohort, 7.3% of patients required craniectomy/craniotomy, and 0.52-5.2% required twist drill/burr hole within 180-days post-MMAE.
Table 1: Baseline Characteristics of the MMAE Cohort
| Characteristic | Value |
|---|---|
| Mean Age at MMAE | 71.2 ± 13.5 years |
| Male | 73.3% |
| White | 69.6% |
| Black/African American | 13.6% |
| Other/Unknown | 16.8% |
| Craniectomy/Craniotomy Prior to Admission | 12.0% |
| Previous Twist Drill/Burr Hole Prior to Admission | 15.7% |
| Antiplatelet Medication within Three Months of Admission | 20.4% |
| Anticoagulation Medication Prior to Admission | 40.3% |
Table 2: Common Comorbidities of the MMAE Cohort
| Comorbidity | Percentage |
|---|---|
| Essential Hypertension | 71.3% |
| Other Heart Diseases within Ten Years | 62.8% |
| Ischemic Heart Diseases within Ten Years | N/A |
| Smoking | N/A |
| Type 2 Diabetes | 27.2% |
Our study provides additional evidence reinforcing the existing results in the literature that MMAE can be safe and effective in treating cSDH. MMAE has been previously reported as an effective standalone therapy even in the setting of midline shifts slightly greater than 5 mm and thickness above 10 mm in specific patient populations (i.e., asymptomatic or mildly symptomatic patients).
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