A physician writing on a clipboard

When does a patient need early referral to a cerebrovascular neurosurgeon?

It’s never too early to refer a patient for aneurysms and other serious cerebrovascular conditions, according to neurosurgeon Joshua Catapano, MD.

  • April 30, 2025
Joshua Stephen Catapano, MD, smiles in a white lab coat, blue dress shirt and silver tie
Joshua Stephen Catapano, MD

According to Penn Medicine neurosurgeon Joshua Catapano, MD, it’s never too early to collaborate with a cerebrovascular surgeon and refer a patient for aneurysms, cavernous malformations, and other serious cerebrovascular conditions.

An early referral offers many benefits and can prevent risks, delays, and complications.

When does a patient need early referral to a cerebrovascular neurosurgeon?

Aneurysms and cavernous malformations are often managed with a “watch-and-wait” strategy in which providers recommend yearly scans in the community setting for lesions determined to be low-risk.

This approach carries its own risks. Misdiagnosis (and the potential for subsequent suboptimal treatment) are common. Additionally, decisions in the community setting may not be based on the latest evidence, the best testing modality, or the newest surgical approaches. Most critically, delaying referral to a cerebrovascular specialist may impede intervention when a lesion requires surgical intervention.

“Many primary care providers and neurologists don’t refer patients with lesions to a cerebrovascular surgeon early because they think the surgeon is automatically going to do surgery,” Dr. Catapano says. However, this is not always the case. “Some cases warrant surgery, but we are also happy to help community providers conservatively manage patients and monitor lesions for growth or changes.”

“When I collaborate with a community provider from early on, they have direct access to me,” says Dr. Catapano. “We discuss patients at length and, as a team, come up with what the best treatment management strategy is for them. And then they can call any time with questions.”

Benefits of early referral for neurovascular conditions

Referrals made late in the intervention process may inhibit long-term collaborative relationships among the provider, surgeon, and patient. Early referral allows the patient and community provider to establish a relationship with the surgeon before there is an urgent need for care. If and when the patient does require intervention, there are no delays.

In addition, early referral gives the provider access to a valuable resource over the course of patient management. “When I collaborate with a community provider from early on they have direct access to me,” Dr. Catapano observes. “We discuss patients at length and, as a team, come up with what the best treatment management strategy is for them. And then they can call any time with questions.”

Early referral also improves the patient-surgeon relationship, he adds. “It’s important that the patient and I build a relationship, whether we have one visit or we follow the patient for years. It improves the overall experience when it is time to perform surgery.”

Referral guidance for cerebrovascular events

In addition to offering patients the general benefits of early referral, Dr. Catapano offers referral guidance for each of the cerebrovascular conditions treated by the team at Penn Medicine.

Early referral for aneurysms

Patients who have been diagnosed with aneurysm should be referred to a specialist immediately—no matter the size, location, or appearance of the lesion, Dr. Catapano stresses.

In his experience, many providers wait until an aneurysm is 5 millimeters to refer to a surgeon. But aneurysm treatment decisions should be more nuanced than that, he says, especially because almost half of ruptured aneurysms are smaller than that threshold. Some aneurysms as small as 1 or 2 millimeters should be considered for surgery, based on angiogram testing that reveals translucence in the vessel wall.

In addition, aneurysm diagnosis is often based on computed tomography angiography (CTA), a less than reliable modality for this application. By comparison, angiograms offer higher resolution, and as a superior imaging modality, are often able to reverse aneurysm diagnoses. When this occurs, it relieves significant emotional anguish for patients and eliminates the need for yearly scans.

Early referral for cavernous malformations

Patients with cavernous malformations should also be referred early due to the risk of seizures, hydrocephalus, and other serious complications, which can occur even with smaller lesions.

Specialists are best able to assess the nuances of location, the key to cavernous malformation treatment decisions. In addition, Penn Medicine and other centers that handle a large volume of cavernous malformations often conduct clinical trials of novel treatment options which can provide potential treatment alternatives.

Early referral for AVMs

Neurologists often decide to monitor patients with arteriovenous malformations (AVM). However, these patients should be referred early for an angiogram to confirm the diagnosis and inform treatment decisions.

In this condition, an angiogram provides essential information regarding potentially dangerous locations for resection. In such cases, Penn Neurosurgery offers embolization or GammaKnife radiation, which can cure the lesion or shrink it in preparation for surgery.

Early referral for arteriovenous fistulas

Early referral to a specialist and angiogram are also essential for arteriovenous (AV) fistula. The test and expert assessment for AV fistula can differentiate between low-risk and high-risk lesions. High-risk lesions should be treated surgically as soon as possible by an AV fistula specialist, Dr. Catapano says.

Early referral for Moyamoya disease

Any patients with suspected Moyamoya disease should also be referred early to a specialist. Moyamoya treatment decisions involve many nuances, such as:

  • Moyamoya-like disease, also known as Moyamoya syndrome, which mimics the condition but is not the same
  • The “puff of smoke sign” on angiogram that is diagnostic for the disease
  • Symptoms that can be precursors to major events, which patients should be trained to look for
  • The importance of CT perfusion to understand blood flow in these patients

Early referral for carotid stenosis treatment

Many community providers use CTA and ultrasound to monitor carotid stenosis, Dr. Catapano says, but those are not adequate in many patients. He recommends early referral for angiography, especially in patients with 50 percent blockage or symptoms.

Early referral for subdural hematoma treatment

Patients with subdural hematoma should be monitored over time by a specialist who knows when and how to intervene. Some patients may never need treatment. However, some can be treated early and minimally invasively, which can prevent open surgery down the road, says Dr. Catapano.

About the Penn Cerebrovascular Disease Program

The cerebrovascular disease experts at Penn Medicine provide complete care for the spectrum of cerebrovascular disease, offering minimally invasive brain microsurgery, radiosurgery, and endovascular neurosurgery, as well as neurocritical care and neurorehabilitation services.

In addition, as one of only 12 institutions in the nation and the only hospital in our region to be designated a Center of Excellence for Cerebral Cavernous Malformation, Penn Medicine is home to one of the country’s few dedicated centers for patients with this condition.

Clinical consultations and referrals

For a second opinion or provider-to-provider consultation with a Penn Medicine cerebrovascular surgeon, call 877-937-7366 or refer a patient online.

Additional reading

Follow us

Physician updates straight to your inbox

Subscribe to receive the latest clinical updates and news for physicians—including research highlights, case reports, and expert perspectives.