Persistent left superior vena cava with absent right superior vena cava detected during emergent coronary artery bypass grafting surgery

PLSVC occurs in 0.3 % of patients with normal hearts and in 4.5 % of patients with congenital heart disease [1, 2]. PLSVC with absent RSVC (also known as isolated PLSVC) in visceroatrial situs solitus is a very rare venous malformation, occurring in 0.07 to 0.15 % of patients with pacemaker implantations and in 0.09 to 0.13 % of postmortem cases involving congenital heart disease [3–5]. Of those patients with PLSVC, 46 % have other congenital cardiac anomalies, including atrial septal defects, endocardial cushion defects, and tetralogy of Fallot [3].

TEE examinations typically allow for good visualization of RSVC in both the mid-esophageal (ME) bicaval and the ME ascending aorta short-axis views. The combined use of these views is useful for detecting an absent RSVC (Fig. 3). Diagnosis of PLSVC can be confirmed by TEE. In ME views, PLSVC can be depicted close to the left atrial appendage (Fig. 2a). A dilated CS is characteristic of PLSVC and easily visualized in the ME four-chamber view by retroflexing the probe (Fig. 2b). In cases of an absent RSVC, severely increased venous blood flow can result in a giant CS. Enlargement of the CS diameter by more than 1 cm may indicate right atrial hypertension due to anomalous venous return through the CS [6].

In 10 % of PLSVC cases, PLSVC drains into the left atrium (LA) [6]. This causes significant right to left shunt, cyanosis, and paradoxical embolization. Furthermore, drugs can flow directly in the systemic circulation when administered from the left arm. When PLSVC drains into the LA directly, surgical correction should be performed by using an intracardiac baffle [7]. Therefore, when PLSVC is detected by TEE, its entry should be carefully observed. Contrast echocardiography with agitated saline might be helpful for the diagnosis of PLSVC with absent RSVC. Although TEE is very useful for the diagnosis of these venous malformations, it is not so popular in the ordinary clinical setting. Other diagnostic tools such as venous angiography, computed tomography (CT), and magnetic resonance imaging (MRI) could directly visualize these malformations. In the present case, a definitive diagnosis was confirmed with preoperative CT.

PLSVC with absent RSVC itself causes no hemodynamic disturbance [2, 8]. However, various clinical implications are present for establishing CPB and central venous access. In this case, venous drainage for CPB was successful by cannulation into the RA, because bicaval cannulation was not required for the CABG. However, the right-sided open-heart surgical procedure requires venous blood drainage not only from both the superior and inferior vena cava but also from the PLSVC. Direct insertion of the cannula into the CS could result in injury to the CS [9]. The punctuation site for central venous access is a difficult issue. As CS catheterization creates the risk of perforation of the heart, central venous access via the femoral vein might be the safer alternative over that via the SVC [6].

Another issue with abnormal venous drainage is that it sometimes strongly influences the cardiac conduction system. A dilated CS stretches both the atrioventricular node and His-bundle tissue, which can cause tachyarrhythmia and atrioventricular block [6]. Particularly in patients with absent RSVC, sinus node dysfunction occasionally occurs because the early conduction tissue is close to the cardinal venous tissue [4]. Although the patient maintained a sinus rhythm preoperatively, arrhythmias certainly represent an issue that anesthesiologists should carefully note preoperatively.