CT angiography for diagnosis and subcategorization of unroofed coronary sinus syndrome.

Background: To evaluate the role of CT angiography (CTA) in the diagnosis and subcategorization of unroofed coronary sinus syndrome (URCS). Methods: We retrospectively analyzed 46 URCS patients diagnosed by CTA. Based on the defect location and size of coronary sinus (CS), URCS was divided into four types: complete defect as type I, partial defect of proximal CS as type II, partial defect of distal CS as type III, partial defect in which a communication occurs between CS and left atrial as type IV. According to presence of left superior vena cava (LSVC), all types were divided into 2 subtypes as a and b. All 46 patients underwent echocardiography. Results: According to subcategorization of URCS by CTA, type I was observed in 23 cases (Ia 7, Ib 16), type II in 10 cases (IIa 3, IIb 7), type III in 12 cases (IIIa 3, IIIb 9), and type IV in 1 case classified as IVb subtype. In these 46 cases, 21 were detected by echocardiography as URCS (46%). The sensitivity of echocardiography in detecting URCS was significantly lower compared with cardiac CTA (P<0.05). In type I patients, the mean CS diameter indexed to body surface area (CS index) was larger than other types (P<0.05). Thirty patients were successfully treated by surgery and the diagnosis of URCS was confirmed by operative findings. Among them, data were available in 22 cases for analysis; and patients with types I, II and IIIa differ significantly from those with types IIIb and IV (P<0.05) with respect to surgical repair. Conclusions: CTA and imaging reconstruction can provide excellent anatomical delineation of the heart, great vessels, and CS, and allows for precise diagnosis of URCS. This CTA classification scheme of URCS is simple and easy to use, and has important clinical implications for diagnosis and treatment.