EQUIPMENT FOR
TRANSSEPTAL PUNCTURES
PETER LEONG-SIT, DAVID CALLANS
The transseptal puncture was originally described in the late 1950s by Drs. John Ross, Edwin Brockenbrough, and Eugene Braunwald.1,2 Over several years, with experiments on canines, human cadavers, and then patients, they developed the most basic equipment required for a percutaneous transseptal puncture. Although the initial reported series of 450 transseptal punctures in 1962 gave rise to relatively low complication rates,3 major complications occurred, such as aortic puncture, pericardial tamponade, systemic arterial embolism, and inferior vena cava perforation.4 Expectedly, there have been many advances in technology and in the equipment used over the last 5 decades. These improvements allow the clinician to perform a safer transseptal puncture and more frequently avoid the many possible complications. More recent publications would suggest that the procedure still has tangible risks: a 2.7% risk of pericardial effusion, a 1.0% risk of pericardial tamponade, and a 0.4% risk of a neurologic event.5
The basic set of tools required for the procedure includes a wire to guide the insertion of sheaths into the heart, a long needle to puncture the interatrial septum, and a long sheath to traverse the septum. Optional auxiliary tools to assist in a safer procedure include air filters, X-ray contrast dye, pressure lines, various forms of echocardiography, and catheters placed for anatomic reference. Emerging tools include laser or radiofrequency assistance to puncture the interatrial septum, needle systems with additional safety features, and equipment designed for use with internal jugular vein access.
Needles
Arguably, the most critical advance in the percutaneous transseptal puncture was the invention and modification of the transseptal needle. Most of this work was originally done by Ross, who invented the transseptal needle, and by Brockenbrough, who modified it to a version not dissimilar to the modern needle. Since that time, several manufacturers have devised versions of the transseptal puncture needle. All versions of the needle are long, curved, and stainless steel, and designed to be introduced via the right femoral vein. The needles have an arrow-shaped handle that indicates the direction of the needle tip and that allows for steerable control of the rotational direction of the needle tip (Figure 5.1). The needles are 18-gauge in adult-sized sheaths (19-gauge in pediatric needles) and taper to a size of 21-gauge. The curve of the needle between the shaft and the needle tip varies with different size options. For example, St. Jude Medical has a series of transseptal needles. The Brockenbrough (BRK) is a small-curved needle with a shaft-to-needle-tip angle of approximately 19°, whereas the BRK-1 is a large-curved needle with an angle of approximately 55°. Pediatric options also include the BRK-2 with an intermediate curve. The length of the needle also varies depending on the length of the sheath being used. The majority of sheaths require a standard-length needle of 71 cm (pediatric needles are 56 cm). Longer sheaths with steerable mechanisms, such as the Agilis NxT Steerable Introducer sheath (St. Jude Medical Inc, St. Paul, MN), require a longer needle of 98 cm. All needles come with a stylet that fills the lumen of the needle and extends beyond the needle tip. The stylet is used when introducing the needle into a sheath; it prevents the needle tip from scraping the inner lumen of the sheath.
Introducers and Sheaths
Many sheaths are available for use with the transseptal puncture needle. The shape and curve of the sheath are designed to first assist in providing support to the transseptal needle during the transseptal puncture and, more importantly, to give support and stability to the mapping or ablation catheter to reach various parts of the left atrium and ventricle. Manufacturers have designed several different sheaths to serve this purpose.
General design features of these sheaths include a side port with a hemostasis valve. All come with a dilator that fits within the lumen of the sheath and extends beyond the sheath tip to add structural support during cannulation of the vein as well as during transseptal puncture.
Generally, sheaths can be categorized as steerable or fixed. An example of a basic multi-purpose fixed sheath would be the Mullins-style sheath manufactured by several companies. The sheath is approximately 60 cm long with a large distal curve of 180° and a diameter of 6 cm. It is generally softer and more pliable than newer sheaths and provides less structural support to the catheter. St. Jude Medical, Inc, C. R. Bard, Inc, and Boston Scientific, Inc have each developed a series of sheaths with varying curves (Figure 5.2
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