A.Kocher Technique: A Simplified Universally Applicable Approach for Aortic Root Enlargement

The implantation of a small prosthesis during surgical aortic valve replacement (SAVR) should generally be avoided because patient–prosthesis mismatch is a known risk factor for adverse outcomes. Several techniques have been described to facilitate aortic root enlargement among others by Nicks, Manouguian, Rastan, Konno, Nuñez, and their colleagues.^1–4

Recently, the topic has gained traction with the Y incision proposed by Bo Yang. ⁵ Prompted by his very important work, we developed our own technique to further simplify root enlargement and facilitate a broader applicability. Our modification of aortic root enlargement, a hybrid between the simple Nicks procedure and the more complex but effective Y-incision, aims to provide a reliable enlargement of more than 2 sizes without the need for aortic transection or previous planning for root enlargement.

This report presents a 68-year-old female patient with severe aortic valve stenosis (mean pressure gradient = 50 mm Hg; aortic valve area = 0.7 cm²) and an annular diameter of 21 mm. Following cardioplegic arrest, a routine hockey-stick incision into the mid-noncoronary sinus was made. At this point, the surgeon still had the option to go for a regular AVR or to enlarge the annulus. If enlargement is required after decalcification and sizing, the incision can be continued downwards into the nadir of the noncoronary sinus. The cut was extended through the attachment line of the noncoronary cusp and directed leftwards precisely to the center of the bottom line of the subaortic curtain (i.e., the middle of the left/noncommissure). The cut to the right ended at the fibrous trigone. This inversed T-shaped incision ran slightly above and in parallel to the hinge line of the anterior mitral valve leaflet. The distance of the incision at the base was measured; our experience has shown that, on average, the created opening measures 2.5 cm in length, corresponding to roughly 110° of the aortic annular circumference. A curved patch out of a regular 30 mm aortic tube graft was tailored with the base congruous to the size of the annular incision plus an extra 4 mm in width for a 2 mm suture margin on both sides of the patch. Toward the sinotubular junction, the width of the aortic graft was increased by 1 cm to create a neo noncoronary sinus. The cranial end of the patch was tapered in a triangular fashion for closure of the aortotomy. The patch was implanted using a 4.0 polypropylene running suture. Pledgeted sutures for valve prosthesis implantation were placed in a standard fashion at the left and right coronary sinus. Within the patch, sutures were placed without pledgets horizontally and continued in an almost straight suture line starting slightly below the tips of the left/noncommissures and right/noncommissures. This technique allows for an almost anatomical prosthetic valve implantation with only a slight tilting in the noncoronary neo sinus. Both coronary ostia were uncompromised because the implantation line followed the insertion line in the left and noncoronary sinus as in standard prosthetic valve implantation. The aortotomy was closed including the remaining patch.

In summary, the root enlargement as proposed by Alfred Kocher and performed routinely at our institution is eclectic as it combines several considerations of the previously known techniques resulting in a simplified broadly applicable, reproducible enlargement procedure. Furthermore, we could show that with this simple procedure, a 2 sizes larger valve prosthesis could be implanted in all our patients. This aortic root enlargement is called the A.Kocher Technique at our center.