A simplified approach to determine the ventriculoaortic junction diameter in the reimplantation procedures

Central MessageVentriculoaortic junction diameter was associated with effective height and cusp height after reimplantation; therefore, the postoperative optimal veitriculoaortic junction diameter is predictable.See Commentary on page 32. Ventriculoaortic junction diameter was associated with effective height and cusp height after reimplantation; therefore, the postoperative optimal veitriculoaortic junction diameter is predictable. See Commentary on page 32. In aortic valve–sparing procedures, sufficient effective height (EH) is essential for long-term aortic valve durability.1Schäfers H.J. Schmied W. Marom G. Aicher D. Cusp height in aortic valves.J Thorac Cardiovasc Surg. 2013; 146: 269-274Google Scholar The plication of the nodule of Arantius (central plication) and the free margin resuspension with polytetrafluoroethylene sutures are performed to obtain sufficient EH, but overcorrection brings the immobility of the cusp and the gap in the central coaptation zone. In the reimplantation procedure, reducing the ventriculoaortic junction (VAJ) diameter with the proximal suture line is another option for increasing the coaptation height2de Kerchove L. Mastrobuoni S. Boodhwani M. Astarci P. Rubay J. Poncelet A. et al.The role of annular dimension and annuloplasty in tricuspid aortic valve repair.Eur J Cardiothorac Surg. 2016; 49: 428-437Google Scholar; however, the degree of the reduction must be decided at the beginning of the procedure before the cusp configuration is completed. Originally, the internal radius of the VAJ was assumed to be two-thirds of the cusp height and the external diameter of VAJ was obtained by adding 4 to 6 mm to the internal diameter, which was equal to the graft diameter to be used.3David T.E. Feindel C.M. An aortic valve-sparing operation for patients with aortic incompetence and aneurysm of the ascending aorta.J Thorac Cardiovasc Surg. 1992; 103: 617-622Google Scholar David and colleagues4David T.E. David C.M. Feindel C.M. Manlhiot C. Reimplantation of the aortic valve at 20 years.J Thorac Cardiovasc Surg. 2017; 153: 232-238Google Scholar reported the excellent long-term outcomes of the procedure and clarified the validity of the theory. With the recent advancement of cardiac computed tomography (CT), aortic root anatomy has been well understood as performed before transcatheter aortic valve implantation. We characterized the postreimplantation root anatomy using cardiac CT and investigated the relationship among the intraoperatively measured cusp height (geometric height: GH), the EH, and the VAJ diameter. All image acquisitions were performed using a third-generation dual-source CT scanner. We used a standard protocol of electrocardiographically gated coronary arterial CT angiography. All image analyses were performed using a commercially available workstation (Ziostation2 version 2.9.7.1; AMIN Co, Ltd, Tokyo, Japan; Ziosoft Inc, Tokyo, Japan). The VAJ plane was semiautomatically defined by identifying the nadir of each aortic valvular hingeline (the nadir of each sinus). A perpendicular line was given from the top of the central coaptation of cusps to the VAJ plane, the distance from the intersection of them to the nadir of each sinus was measured, and then the average length of them was taken as the radius of VAJ. The length of the perpendicular from the top of central coaptation of cusps to the VAJ plane was defined as EH. The study protocol was reviewed and approved by our institutional review board, and the need for additional informed consent was waived (Brain and Heart Center, Himeji, B210050, October 15, 2021). Cardiac CT and the measurement of the values were performed in 27 patients (all had tricuspid aortic valve), and then we noticed that the EH after the reimplantation was approximately equal to the coaptation height (Figure 1, A). The proximal sutures in the reimplantation might cause restrictive effect for the hinge point of the cusps, which would induce such a phenomenon. Because of the difference in GH and EH of each cusp, the mean value of each (GH – EH) × 2 was adopted to compare to the VAJ diameter. There was correlation between the mean (GH – EH) × 2 and the VAJ diameter (Figure 1, B, and Table E1). Based on the results, the optimal VAJ diameter could be predicted by the intraoperatively measured GH and the target EH. Although the correlation was represented with the complex equation, the dots were included in the range of the simplified equation (the mean [GH – EH] × 2 ± 3 = VAJ diameter) (Figure 2 and Figure E1). To obtain sufficient EH even in the smallest cusp in each patient, the modified formula ([the minimum GH – the target EH] × 2 = VAJ diameter) was adopted in the latest 6 patients. Before tying down the aortic proximal sutures, we inserted a Hegar dilator of 2 to 3 mm smaller size than the estimated VAJ diameter into the left ventricular outflow tract, the sutures below the commissures were tied down tightly, and then the others were just taut (Figure E2). In those patients, postoperative VAJ diameter was almost identical to the estimated values, and the EH was above the target value (9 mm) in all cusps. In case of preoperative severe cusp prolapse with cusp bending, central plication was expected to be definitely necessary. Central plication might reduce cusp height; therefore, a smaller estimated VAJ diameter than that from the formula was adopted to obtain sufficient coaptation. We refer to echocardiography data from the Japanese normal population5Daimon M. Watanabe H. Abe Y. Hirata K. Hozumi T. Ishii K. et al.Normal values of echocardiographic parameters in relation to age in a healthy Japanese population: the JAMP study.Circ J. 2008; 72: 1859-1866Google Scholar and set the limit value of the reduced VAJ diameter >13 mm/m2 in avoidance of aortic stenosis caused by overreduction of VAJ diameter. In the meantime, there are no patients showing mean pressure gradient through aortic valve >15 mm Hg. In summary, a simplified formula using the intraoperatively measured GH and the target EH could predict the optimal VAJ diameter. Figure E2The proximal sutures are being tied with insertion of a Hegar dilator into the left ventricular outflow tract. In tricuspid aortic valve, we pull up the commissures vertically on the original position in the graft and then move the position slightly if minor prolapse exists. Major prolapse is corrected with cusp plication or free margin resuspension. The EH was 9.4 ± 0.4 mm in 6 patients with the simplified formula, whereas 7.0 ± 1.3 mm in the remaining 21 patients.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Table E1Measurements of cardiac computed tomography in the reimplantationLRNMeanGH, mm20.8 ± 2.021.1 ± 2.022.4 ± 2.3EH, mm7.7 ± 1.57.6 ± 1.67.9 ± 1.4GH – EH, mm13.1 ± 2.013.5 ± 2.414.5 ± 2.413.7 ± 1.7Basal ring radius, mm13.2 ± 1.613.9 ± 2.313.4 ± 1.813.5 ± 2.1L, Left coronary cusp; R, right coronary cusp; N, non coronary cusp; GH, geometric height; EH, effective height. Open table in a new tab L, Left coronary cusp; R, right coronary cusp; N, non coronary cusp; GH, geometric height; EH, effective height. Commentary: Standardized adaptation of aortic valve reimplantation to cusp geometryJTCVS TechniquesVol. 12PreviewThe goal of valve-preserving root replacement is the restoration of normal aortic valve form, coaptation, and thus function to achieve the best valve durability. To achieve this, the operation must accommodate the geometry of the cusps, which may differ in size. Several studies have shown that effective cusp height1 is a good indicator of valve configuration. In normal aortic valves, it has a close correlation with geometric cusp height.2,3 To achieve normal aortic configuration with adequate coaptation through valve-preserving surgery, modification of annular and sinotubular dimensions may be helpful.