Persistent Pulmonary Hypertension in Corrected Congenital Left Circumflex Artery to Coronary Sinus Fistula: A Case Report and Literature Review.

Background: Coronary artery fistulas (CAFs) are rare congenital anomalies, with the left circumflex artery to coronary sinus (LCx-CS) fistula representing an uncommon subtype. Pulmonary hypertension (PHTN) may arise as a consequence of large, unrepaired CAFs. While most patients experience improvement following surgical repair, there are instances where PHTN persists, necessitating ongoing monitoring and pharmacological intervention. Case Description: We present the case of a middle-aged woman with no significant medical history who presented with dyspnea. She was found to have PHTN secondary to a large LCx-CS fistula. She underwent surgical ligation of the fistula. Postoperatively, the patient remained symptomatic, with elevated pulmonary arterial pressure persisting, prompting the initiation of triple therapy comprising macitentan, selexipag, and sildenafil. This therapeutic regimen significantly resolved her symptoms and improved her functional capacities. Discussion: This case highlights the hemodynamic implications associated with a long-standing LCx-CS fistula. Although congenital, such anomalies can remain asymptomatic for extended periods. The most likely hypothesis is that a large chronic fistula can cause irreversible histopathological changes to the pulmonary microvasculature, resulting in a "point of no return" and leading to persistent symptoms even after anatomical correction. In most reported scenarios, the surgical or interventional correction of CAF results in symptom resolution and hemodynamic improvement. However, the described case illustrates an atypical presentation, revealing the potential for sustained elevation of pulmonary arterial pressures. Consequently, this necessitates ongoing pharmacological management. Conclusion: While LCx-CS fistulas are infrequent and often asymptomatic, chronic fistula cases may result in various complications and symptomatic presentations. The case illustrates a rare case of persistent PHTN in a corrected LCx-CS fistula. Thorough follow-up, early diagnosis, and timely interventions, complemented by pharmacotherapy when necessary, are essential in managing these complex clinical scenarios.