Hemodynamic Vise

Transcript of the video: Hemodynamic vise is the term given to compression of a vertical vein, which ascends to the brachiocephalic vein, between a bronchus and pulmonary artery. This produces a vicious cycle and that is why it is known as hemodynamic vise in certain types of congenital heart diseases which have a vertical vein.

This is the typical location of the hemodynamic vise, between the pulmonary artery and left bronchus. When the vertical vein ascends, it is compressed by these two. When it is compressed, pulmonary venous drainage is obstructed partially, which leads to increase in the pulmonary venous pressure. Pulmonary venous pressure is transmitted back on to the pulmonary arterial pressure. So pulmonary arterial pressure increases, which will increase the compression. And, when the pulmonary venous pressure rises further, it will again increase the pulmonary arterial pressure. So that is the vicious cycle which can occur in total anomalous pulmonary venous connection, with a vertical vein draining upwards, usually on the left side, producing worsening of pulmonary venous pressures and pulmonary arterial pressures. Hence it is known as hemodynamic vise.

Though the hemodynamic vise is typically located on the left side, occasionally, it can occur on the right side as well. Sometimes there is a right vertical vein, which rises upwards between the right pulmonary artery and the right bronchus. Then also, it can produce compression and cause a similar situation like the hemodynamic vise on the left side. This is much less common.

The previous two descriptions of hemodynamic vise was in total anomalous pulmonary venous connection. It has also been reported in partial anomalous pulmonary venous connection. In a case of cor-triatriatum, pulmonary veins from the part of right lung and the whole of left lung, formed the vertical vein and ascended up. So there was a hemodynamic vise compression between the pulmonary artery and left bronchus, as in a typical total anomalous pulmonary venous connection. The right sided remaining pulmonary veins, joined the additional chamber in cor-triatriatum. The other parts which were anomalous formed the common venous chamber and ascended up as a vertical vein, which was compressed by the hemodynamic vise. While the remaining right sided veins drained into the additional chamber, which was part of the cor-triatriatum. You know that in cor-triatriatum sinister, on the left side, there is an additional left atrial chamber. So that is why it is called three chambered atrium. Cor-triatriatum can also occur on the right side, then it is known as cor-triatriatum dexter. That is still rarer. All these anomalies are rare, and much less common than the hemodynamic vise occurring on the left side in typical total anomalous pulmonary venous connection or TAPVC.