Techniques and results of variceal pressure measurements.

Pressure in esophageal varices can be measured by puncture of a varix, or using an endoscopic gauge or by means of an endoscopic balloon. Puncture is usually regarded as an invasive technique in contrast with the other two. Puncture technique has been considered as the "gold standard" to which other methods of measurement should be compared but its results have not been analyzed critically until recently. The pressure gauge has given reliable pressure measurements in vitro, but results in vivo are still controversial. The new technique using an endoscopic balloon has been assessed in vitro and in vivo, and has given reliable pressure measurements. Studies have been performed by either using the needle puncture technique or the endoscopic gauge. It has been shown that pressure in esophageal varices varies during respiratory cycle, but that the pressure gradient between varices and esophageal lumen (transmural pressure) remains unchanged. Similarly, during Valsalva's maneuver, transmural pressure remains unchanged in most cases in spite of a rise in variceal pressure. Pressure in esophageal varices correlated with portal pressure in spite of possible difference in their respective values. The effects of pharmacological substances on variceal pressure has also been investigated using the above mentioned techniques. Non-invasive techniques should allow measurement and studies on a broader scale.