Coronary-Driven Cerebral Revascularization in Type 2a Takayasu Arteritis: A Rare Multisystem Collateral Phenotype

Abstract

Takayasu arteritis (TA) is a chronic, granulomatous large-vessel vasculitis affecting the aorta and its branches. This report describes a 33-year-old woman with longstanding, unsupervised disease who developed extensive collateral revascularization, including rare coronary-carotid and coronary-vertebral pathways. Coronary angiography revealed normal epicardial coronary arteries but demonstrated collateral filling of the carotid system from the left coronary circulation. Computed tomography angiography identified complete occlusion of all aortic arch branches and extensive systemic, thoracic, pelvic, and visceral collateral pathways, including the Winslow pathway.

The axillary, carotid, and vertebral arteries were supplied by new channels from the internal thoracic, intercostal, paraspinal, pelvic, and coronary arteries. This case shows a rare pattern of collateral blood flow that maintains blood supply to the brain and upper limbs in advanced Type 2a TA. It highlights the importance of using multiple imaging methods to map these complex networks for diagnosis, risk assessment, and procedural planning.

Introduction

Takayasu arteritis (TA) is a rare, idiopathic, chronic, granulomatous vasculitis that predominantly involves the aorta and its major branches, leading to progressive stenosis, occlusion, or aneurysmal degeneration of large arteries. Clinically, it often presents with an initial systemic inflammatory phase characterized by constitutional symptoms, followed by a chronic phase in which ischemic manifestations reflect established vascular damage and collateral formation [1,2]. Angiography remains the cornerstone for defining the pattern of arterial involvement and for classifying TA.

The widely used Numano (Hata) angiographic classification divides TA into six types based on segmental aortic and branch involvement, with Types 1 and 2a predominantly affecting the aortic arch and its branches [3]. In comparative cohorts from Japan and India, arch involvement (Types I/IIa) has been reported as more frequent in Japanese patients, whereas abdominal aortic and renal artery disease (Types IV/V) is relatively more common in Indian patients, although all patterns can occur in both populations [3,4].

Chronic occlusion of major vessels in TA stimulates extensive collateral circulation. In aorto-occlusive disease, systemic-systemic and visceral-systemic collateral pathways such as the internal thoracic-epigastric (Winslow) pathway, intercostal-paraspinal networks, and iliac-lumbar-epigastric arcs have been well characterized on computed tomography (CT) angiography and catheter angiography [5,6]. Similar pathways have been documented in TA, where the Winslow pathway and chest wall collaterals may significantly contribute to limb and visceral perfusion and may even manifest clinically as prominent abdominal wall vessels [4,7]. Reports of coronary-to-cerebral collateralization in TA, however, remain rare.

This report presents a case of Type 2a TA with complete occlusion of the aortic arch branches, in which cerebral and upper extremity perfusion was maintained by an exceptionally rich network, including direct coronary-carotid, as well as extensive thoracic, abdominal, pelvic, and Winslow pathway collaterals.

Case presentation

A 33-year-old woman presented with chest pain of two weeks' duration and exertional dyspnea. She had a prior diagnosis of TA in 2009, had been lost to follow-up, and had received unsupervised steroid therapy. Her medical history also included a previous cerebrovascular accident with residual left hemiparesis.

On examination, her blood pressure was 100/60 mmHg in both arms without discrepancy. Her pulse was of low volume with a heart rate of 108 beats/minute, and her temperature was 98.6°F. Cardiovascular and respiratory examinations were unremarkable. Laboratory investigations, including erythrocyte sedimentation rate, electrocardiogram, and transthoracic echocardiography, were within normal limits.

Invasive coronary angiography demonstrated normal epicardial coronaries: the left main coronary artery, a Type 3 left anterior descending artery, a nondominant circumflex artery, and a dominant right coronary artery were angiographically normal. However, prominent coronary-carotid collaterals were observed, with filling of the left common carotid artery in the setting of occluded brachiocephalic and left subclavian arteries (Figure 1A). Computed tomography (CT) aortography using a 128-slice system revealed complete occlusion of all branches of the aortic arch with absent opacification and thinning of the involved arteries. Bilateral complete stenosis of the proximal common carotid arteries with no contrast opacification is shown in Figure 1B.

Figure 1. Coronary angiogram and CT aortography.

Prominent coronary-carotid collaterals were observed, with filling of the left common carotid artery (A) and bilateral complete stenosis of the proximal common carotid artery (B)

CT: computed tomography

Bilateral proximal subclavian arteries were occluded, whereas the axillary arteries were reformed via lateral thoracic arteries and collaterals from the left coronary artery (Figure 2A). Additional systemic and collateral pathways included connections from the internal iliac and lumbar arteries to the lower intercostal arteries, and a collateral arising from the deep circumflex branch of the left common femoral artery that anastomosed with the internal costal arteries (Figure 2B).

Figure 2. VRT image of thoracic, pelvis, and abdominal cavity.

(A) Bilateral proximal subclavian arteries were occluded (yellow arrows), whereas the axillary arteries were reformed via lateral thoracic arteries (blue arrows). (B) Additional systemic and systemic collateral pathways included connections from bilateral internal iliac arteries to lower intercostal arteries (yellow arrows) and a collateral arising from the deep circumflex branch of the left common femoral artery, anastomosing with internal costal arteries (blue arrow)

VRT: volume rendering technique

Bilateral terminal portions of the common carotid arteries were reformed via internal mammary arteries through the Winslow pathway, involving the inferior epigastric, superior epigastric, and internal mammary arteries (Figure 3).

Figure 3. MIP image of abdominal and thoracic cavity.

The systemic collateral pathway of Winslow is demonstrated, formed by the internal mammary artery (yellow arrow), the superior epigastric artery (red arrow), and the inferior epigastric artery (blue arrow)

MIP: maximum intensity projection

Visceral-systemic collaterals were also seen between the common hepatic artery and the internal thoracic artery (Figure 4).

Figure 4. MIP image of the abdominal and thoracic cavity axial image.

Visceral-systemic collateral (red arrow) pathway is noted between the common hepatic artery (blue arrow) and the right internal iliac artery (yellow arrow)

MIP: maximum intensity projection

Overall, multiple systemic and visceral collateral pathways were identified, supporting cerebral and upper limb perfusion in the context of arch-vessel occlusion. The angiographic pattern was consistent with Numano Type 2a TA. The patient was managed with medical immunosuppressive therapy and close follow-up.

Discussion

TA is characterized by progressive large-vessel inflammation culminating in luminal stenosis or occlusion. Once a critical obstruction develops, tissue survival depends on the development and recruitment of collateral channels through the remodeling of preexisting arterioles and, to some extent, neoangiogenesis [1,2]. Systemic-systemic collateral pathways involving intercostal and paraspinal arteries are commonly observed in chronic aorto-occlusive conditions, including TA [5].

In arch-vessel occlusive disease, cerebral perfusion is usually safeguarded by the vertebrobasilar circulation and the circle of Willis. When TA leads to occlusion of the brachiocephalic, carotid, and subclavian arteries, a so-called "bald arch" pattern, conventional posterior-to-anterior compensation may be insufficient, and a variety of alternative collaterals emerge from internal thoracic, intercostal, paraspinal, abdominal, and pelvic arteries [4-6]. Prominent Winslow pathway collaterals linking the internal thoracic, epigastric, and external iliac systems have been described in TA with middle aortic syndrome, sometimes visible as engorged abdominal wall vessels and associated with limb ischemia or hypertension [7].

In this patient, there was a textbook expansion of these systemic routes, including intercostal, paraspinal, chest wall, iliac, and epigastric collaterals, as well as a well-developed Winslow pathway. Collectively, these channels reconstituted distal carotid, vertebral, and subclavian territories.

Beyond systemic routes, only a small number of reports describe coronary arteries directly supplying cerebral vessels in TA. Uzunlar et al. reported what was considered the first case of coronary-carotid collaterals, with left anterior descending and circumflex arteries feeding the carotid circulation in a patient with arch-vessel occlusion [8]. Singhal and Pathak later described right coronary artery collaterals to both carotid arteries and the right subclavian artery in TA, again in the setting of severe arch involvement but structurally normal coronary arteries [9]. More recently, Chupin et al. described coronary-vertebral collaterals in a severe case of TA with a bald arch [10].

This case aligns with this rare group but is distinctive because coronary collaterals supplied both carotid and vertebral arteries concurrently. These coronary pathways coexisted with extremely rich systemic and Winslow collaterals, demonstrating a multilayered redundancy of cerebral inflow. To the authors' knowledge, such a combination of coronary-carotid and coronary- vertebral collaterals, together with extensive systemic-systemic and visceral-systemic channels in Type 2a TA, is very uncommon in the literature and further extends the spectrum of adaptive collateralization in this disease.

Coronary arteries acting as donor vessels for cerebral circulation raise the possibility of coronary steal, in which brisk extracardiac flow could theoretically compromise myocardial perfusion. However, consistent with prior reports, this patient had angiographically normal epicardial coronary arteries and no demonstrable myocardial ischemia, suggesting that in some cases these collaterals represent a well-tolerated adaptation rather than a clinically significant steal phenomenon [9,10]. Nonetheless, awareness of this potential is important, particularly if symptoms of angina or perfusion defects are present.

From a procedural standpoint, recognition of such collateral is critical. Harvesting the internal thoracic artery for coronary bypass or performing thoracic or abdominal surgery may inadvertently compromise vital collateral pathways, as demonstrated in both TA and aortoiliac occlusive disease [5-7]. The angiographic pattern in this patient, with complete involvement of the arch and its branches but without clear dominant abdominal aortic or renal lesions, corresponds to Numano Type 2a disease [3].

This pattern has been associated with a high burden of cerebrovascular and upper extremity ischemia, making collateral assessment particularly relevant [3,4]. Modern CT angiography and digital subtraction angiography provide complementary information: CT delineates the three-dimensional course of systemic and visceral collaterals, while coronary angiography defines intracardiac donor vessels and dynamic filling patterns. Case series and reviews of TA imaging emphasize that thorough mapping of collateral routes influences decisions about revascularization, graft selection, and long-term surveillance [4,5,7].

In summary, this case demonstrates that in advanced Type 2a TA with arch occlusion, the body may recruit multiple hierarchical collateral networks, including coronary, internal thoracic, paraspinal, abdominal, and pelvic vessels, to preserve cerebral and upper extremity perfusion. Recognizing these patterns is essential for accurate risk assessment and safe planning of surgical or endovascular interventions.

Conclusions

This case highlights an exceptionally rare collateral phenotype in advanced Type 2a TA, characterized by simultaneous coronary-carotid collateralization coexisting with extensive systemic and visceral collateral networks, including the Winslow pathway. These findings expand the spectrum of adaptive vascular remodeling described in TA and demonstrate the remarkable capacity of chronic arterial occlusion to recruit unconventional pathways for maintaining cerebral and upper extremity perfusion. Comprehensive multimodality imaging is indispensable for accurately delineating these collateral routes, guiding risk stratification, and informing surgical or endovascular planning to prevent inadvertent disruption of critical collateral circulation. Recognition of such complex collateral anatomy is essential for optimizing management in patients with advanced large-vessel occlusive disease.