Unrepaired Truncus Arteriosus Type 1 With Eisenmenger Syndrome and Recurrent Embolic Strokes: An Adult Case Report

Introduction

Truncus arteriosus is a rare congenital heart defect characterized by a single arterial trunk that overrides a ventricular septal defect (VSD) and gives rise to the systemic, pulmonary, and coronary circulations [1]. It accounts for approximately 1–2% of all congenital heart anomalies. According to the Collett and Edwards classification, Type I truncus arteriosus is defined by a short main pulmonary artery that bifurcates into right and left branches, both arising from the posterior aspect of the common arterial trunk [2]. The standard of care involves early surgical repair within the first few weeks of life to separate the circulations and close the VSD [3].

Without early surgical intervention, the exposure of the pulmonary vasculature to systemic pressures leads to rapid and irreversible remodeling of the pulmonary arterioles. This progression results in Eisenmenger syndrome, a condition defined by severe pulmonary vascular disease and pulmonary hypertension that exceeds systemic pressure, causing a reversal of the shunt from left-to-right to right-to-left (resulting in cyanosis) [4]. Adult survival without repair is exceptionally rare, and these patients face a multitude of multisystem complications, including chronic hypoxemia, arrhythmias, and heart failure.

A critical but often under-recognized complication in this population is the susceptibility to cerebrovascular accidents. The risk of thromboembolic stroke in Eisenmenger physiology is multifactorial, driven by secondary erythrocytosis (hyperviscosity), stasis of blood within dilated pulmonary arterial aneurysms, and the potential for paradoxical embolization across the septal defect. Management of these risks is challenging, as the bleeding risk associated with anticoagulation must be balanced against the thrombotic risk inherent to the disease.

This report describes the case of a 44-year-old woman with congenital Eisenmenger syndrome and unrepaired truncus arteriosus type 1 presenting with recurrent thromboembolic cerebral infarcts.

Case Report

A 44-year-old woman presented to the emergency department with her third neurologic event in 2 months. Each episode was characterized by transient aphasia, right-sided weakness, and vertigo lasting several minutes to hours, without full loss of consciousness. She had a known diagnosis of unrepaired truncus arteriosus type I with Eisenmenger physiology, diagnosed in childhood but never corrected surgically. She had no history of hemoptysis or overt bleeding. At baseline, her oxygen saturation (SpO2) ranged from 70% to 80% on room air, with cyanosis and digital clubbing. Her functional capacity was World Health Organization (WHO) Class II, and she denied exertional syncope or chest pain.

The neurological examination was non-focal. Brain magnetic resonance imaging (MRI), utilizing diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) sequences, revealed 3 acute embolic infarcts in the left frontal and parietal lobes (Figure 1). Computed tomography (CT) angiography of the head and neck showed no large-vessel occlusion or arterial dissection. No hemorrhagic foci were detected. A 48-hour Holter monitor showed no evidence of atrial fibrillation or other arrhythmias.

Transthoracic echocardiography revealed a 15-mm perimembranous VSD with bidirectional shunting and an overriding, severely calcified truncal valve with moderate regurgitation (Figure 2). The truncal valve had 3 thickened cusps with poor coaptation. Spectral Doppler demonstrated continuous left-to-right and right-to-left shunting across the VSD. The right ventricular systolic pressure was estimated at 114 mmHg, with right atrial dilation, moderate right ventricular hypertrophy, and preserved left ventricular ejection fraction (65%). Tricuspid annular plane systolic excursion measured 14 mm, and tricuspid annular tissue Doppler S’ velocity was 8.1 cm/s. Mild tricuspid regurgitation was noted (peak velocity 2.9 m/s).

Cardiac CT was performed to further delineate the anatomy. The sagittal view confirmed the truncal arteriosus anatomy with a dilated truncal root and severe circumferential calcification of the truncal valve (Figure 3). Axial imaging clearly demonstrated the type I configuration, with both the left and right pulmonary arteries originating directly from the posterior aspect of the ascending common arterial trunk (Figure 4). Additionally, the scan identified a posteriorly arising anomalous left main coronary artery coursing between the aorta and left atrium (Figure 5); this was judged to follow a non-malignant course.

Laboratory workup showed a hemoglobin of 19.2 g/dL, hematocrit of 62%, iron level of 32 μg/dL, and ferritin of 9 ng/mL, consistent with secondary erythrocytosis and iron deficiency. N-terminal pro-brain natriuretic peptide (NT-proBNP) was 454 pg/mL, and creatinine was 0.9 mg/dL. Liver enzymes (aspartate aminotransferase [AST]/alanine transaminase [ALT]) and bilirubin were within normal limits. Pregnancy was excluded by beta-human chorionic gonadotropin (beta-hCG) testing, and the patient was counseled on the high risks of pregnancy in Eisenmenger syndrome. Right heart catheterization was not performed due to the perceived risk of paradoxical embolism in the setting of recent cerebral infarcts, bidirectional shunting, and the lack of an interventional indication.

Medical management focused on stroke prevention and pulmonary vasodilation. Dual antiplatelet therapy (aspirin 81 mg and clopidogrel 75 mg daily) was initiated given the recurrent embolic strokes in the absence of documented atrial fibrillation, balanced against the high bleeding risk that precluded full anticoagulation. She was started on sildenafil (20 mg 3 times daily) and macitentan (10 mg daily). These therapies were well tolerated, with a gradual improvement in SpO2 from 72% to 86% over 2 weeks. Continuous low-flow oxygen at 2–3 L/min was prescribed, primarily for nocturnal use and symptom relief.

At the 6-month follow-up, the patient remained neurologically intact with improved exertional tolerance and stable WHO class II symptoms. Her resting SpO2 was 85–88% on therapy. Repeat hemoglobin declined to 17.1 g/dL after the initiation of iron supplementation and improved hydration. She continued dual antiplatelet therapy with no reported bleeding events.

Discussion

This case highlights the exceptional natural course of uncorrected truncus arteriosus type 1 in adulthood and underscores the critical importance of a multidisciplinary approach to manage the sequelae of chronic cyanosis, particularly thromboembolic risk, in patients for whom surgical repair is no longer feasible.

Truncus arteriosus is a severe congenital anomaly that typically carries a poor prognosis without early intervention. The vast majority of untreated infants die within the first year of life due to intractable heart failure [1,2]. Survival into the fourth or fifth decade without surgical repair, as seen in our patient, is extraordinarily rare and accounts for less than 10% of cases of natural (untreated) disease [2,5]. In a landmark survival analysis by Niwa et al, adult survivors with Eisenmenger syndrome had a median survival of 53 years, yet those with complex anatomy like truncus arteriosus generally had higher mortality rates compared with patients with simple shunts [5]. Our patient’s presentation aligns with this rare survivor cohort, demonstrating that with careful medical optimization, longevity is achievable even in the presence of severe pulmonary vascular disease.

A defining feature of this case was the recurrence of embolic strokes, a well-recognized but devastating complication of Eisenmenger syndrome. The pathophysiology of stroke in this population is distinct from that in the general population. It involves a triad of: (1) secondary erythrocytosis leading to hyperviscosity and sludging in cerebral microvessels; (2) in situ pulmonary thrombosis extending into the systemic circulation; and (3) paradoxical embolization across the VSD [6,7]. In a study by Silversides et al, pulmonary thrombi were detected in 20% of Eisenmenger patients, significantly increasing the risk of systemic embolic events [6]. Our patient presented with multiple cortical infarcts, strongly suggesting an embolic etiology likely facilitated by the bidirectional shunting across her large VSD [4,7].

The management of thrombotic risk in this setting is a clinical dilemma. While anticoagulation (eg, warfarin) is standard for embolic stroke, it carries a high risk of life-threatening pulmonary hemorrhage in Eisenmenger patients [7,8]. European Society of Cardiology guidelines recommend a cautious, individualized approach [8]. Given that our patient had no documented atrial fibrillation or deep vein thrombosis, and considering the catastrophic risk of hemoptysis, we opted for dual antiplatelet therapy (DAPT) rather than full anticoagulation. This conservative strategy aligns with data from Yuan et al, which suggests that targeted therapy combined with antiplatelet agents may provide a safer risk-benefit profile for patients without overt arrhythmias [9].

Regarding pulmonary hypertension, our patient was treated with a combination of a phosphodiesterase-5 inhibitor (sildenafil) and an endothelin receptor antagonist (macitentan). The “treat-and-repair” concept was not feasible in this case due to the irreversibility of her pulmonary vascular disease (Eisenmenger physiology), rendering her inoperable [10]. However, advanced pulmonary vasodilator therapy has been shown to improve functional class and survival in this population [11]. The significant improvement in our patient’s oxygen saturation (from 70% to 88%) supports the findings of Dimopoulos et al, who demonstrated survival benefits with advanced therapies even in established Eisenmenger syndrome [11]. Additionally, although nocturnal oxygen therapy remains controversial, we employed it for symptomatic relief, while acknowledging that randomized trials like those by Sandoval et al have not definitively proven a survival benefit [12].

Finally, the identification of the anomalous left main coronary artery arising posteriorly from the truncal root adds another layer of complexity to this case. While coronary anomalies are common in truncus arteriosus (occurring in up to 50% of cases) [1,3], they are usually addressed during neonatal repair. In an adult survivor, the primary concern is whether the course is inter-arterial (malignant), causing ischemia. Fortunately, our patient’s anomaly followed a benign retro-aortic course, requiring no intervention.

In summary, this report confirms that while uncorrected truncus arteriosus is historically lethal, adult survival is possible. Management must shift from “correction” to “preservation”, focusing on rigorous stroke prevention, pulmonary vasodilation, and avoidance of interventions that could destabilize the delicate physiology.

Conclusions

This case highlights the exceptional natural course of uncorrected truncus arteriosus in adulthood. It underscores that for patients with Eisenmenger physiology where surgical repair is not feasible, a multidisciplinary approach focusing on tailored antithrombotic and pulmonary vasodilator therapies is essential for stroke prevention and clinical stability. In this specific case, a conservative strategy using DAPT and targeted pulmonary vasodilators resulted in neurological stability and improved oxygenation at the 6-month follow-up.