Central venous catheterization in a patient with double right internal jugular vein and persistent left-sided superior vena cava draining into the left atrium.

To the Editor

A 56-year-old, hypertensive female was posted for cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for adenocarcinoma of the ovary. Preoperatively, the patient underwent a series of routine investigations including a 2D echocardiogram and a computerized tomography (CT scan) of the abdomen and thorax. The CT scan of the thorax incidentally showed a persistent left superior vena cava (PLSVC) draining into the left atrium [Figure 1a]. Pulse oximetry showed oxygen saturation of 97% on room air, and preoperative arterial blood gas showed a normal PaO2. There was no comment on PLSVC and its draining connection into the left atrium on 2D echocardiogram.

Figure 1

(a) Two venousstructures (IJV) and carotid artery (CA) on an ultrasonography scan of the neck; (b) coronal images showing double superior vena cava with the left superior vena cava opening into the left atrium; (c) coronal images showing double IJV with the left superior vena cava opening into the left atrium; and (d) double IJV on coronal images

In the operating room, arterial catheterization was done for invasive blood pressure monitoring and central venous cannulation was planned. During ultrasonographic scanning of the right neck for internal jugular vein (IJV), two venous structures and carotid artery were seen. The two venous structures were traced distally, and it was found that they joined to become a single unit [Figure 1a-d]. Hence, one of the venous structures seen was cannulated after confirming guide wire position on ultrasound. Surgery lasted for 5 h and was uneventful.

Anatomical anomalies of the IJV such as duplication or fenestration of the vein are uncommon. They may be identified during surgical neck dissection, radiologically and during cadaveric dissections.[1] The presence of two venous structures on neck ultrasound during IJV catheter placement can cause confusion and difficulty in puncture site selection. If the two limbs of a duplicated IJV join the subclavian vein separately at a right angles, it can cause difficulty or failure in the guidewire advancement. The guidewire may also be misplaced either in axillary vein or upwards in the other limb of the duplicated IJV.[2] During the landmark technique (without ultrasonography) of IJV catheter placement, the presence of a duplicate IJV can also result into catheter malposition.

The presence of a PLSVC has various physiological and clinical implications.[3] The majority of the PLSVC drain into coronary sinus and only 0.03% of PLSVC drain into the left atrium in the absence of a coronary sinus or unroofed coronary sinus syndrome (UCSS)[4] or very rarely through the pulmonary vein.[5] The PLSVC draining into the left atrium is usually associated with a right to left shunt and carries the high risk of air or thromboembolism in to the systemic circulation and a great care should be taken to prevent it.[5] The exact type of UCSS in our case is not known, but since our patient was asymptomatic at presentation, we presume that this could be an incomplete type of UCSS. Isolated reports of double IJV or PLSVC draining into the right atrium or very rarely into the left atrium are available in literature, but these two uncommon findings are never reported in single patient.

In this case, central venous cannulation was successful as both IJVs united to form a single vein distally. The cannulation of the left IJV (in case of failure to cannulate the right IJV or upfront cannulation of left IJV) would have resulted in insertion of the catheter into the PLSVC and measured the left atrial pressure. Although measuring the left atrial pressure is a better indicator of the left ventricular end diastolic pressure, it will give an erroneous and misleading value of blood gas and mixed central venous oxygen saturation (if the presence of PLSVC draining into left atrium is unknown).

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Conflicts of interest

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