Schematic Clock Diagram to Assess Aortic Paravalvular Leak

To the Editor, Paravalvular leak (PVL) following valve replacement/repair is a known complication. 2D and 3D transesophageal echocardiography (TEE) is an effective tool to diagnose this complication as it helps in localizing PVLs. PVLs following aortic valve replacement (AVR) have been reported in relation to the cusps, but it does not pinpoint their location as the cusps span an arc of roughly 120o. By convention, for reporting PVLs following mitral valve repair/replacement, a schematic clock diagram has proven helpful as it correlates both 2D TEE and the surgeon’s view. However, a schematic clock diagram has not been described for PVLs following AVR. We, therefore, propose a schematic clock diagram to localize PVL after AVR, aiming to narrow the area of interest to a 30o arc. The purpose of this communication is to improve the reporting of aortic PVLs to a narrower arc to supplement the current convention of reporting in relation to the cusps. According to the anatomy of the aortic root, the noncoronary sinus is adjacent to the interatrial septum, the right coronary sinus is adjacent to the right ventricular outflow tract, and the left coronary sinus is related to the left atrium posteriorly and anterior mitral leaflet inferiorly.[1] The commissure of the noncoronary cusp (NCC) and left coronary cusp (LCC) is located at the midpoint of anterior mitral leaflet.[2] By convention, the aortic valve is situated at the 12 o’clock position of the mitral valve in the surgeon’s view [Figure 1a].[3] We can consider the aortic valve annular circumference to be another analog clock. In keeping with the same directions of the analog clock for the mitral valve, we propound the schematic clock diagram for the aortic valve wherein the 6 o’clock position of the aortic valve will be apposed to the 12 o’clock position of the mitral valve [Figure 1b]. The commissure of NCC and LCC will correspond to the 6 O’clock position in the suggested schematic clock for the aortic valve [Figure 1a and b]. The cusps of the aortic valve form an equilateral triangle during systole.[4] Therefore, the commissure of RCC and LCC will correspond to the 10 O’clock position. Similarly, the commissure of RCC and NCC will correspond to the 2 O’clock position.Figure 1: (a) Surgeon’s view with native aortic and mitral valves. RCC- Right coronary cusp, LCC- Left coronary cusp, AV-Aortic valve, MV- Mitral Valve, AML-Anterior mitral leaflet, PML- Posterior mitral leaflet, LAA- Left atrial Appendage. (b) Surgeon’s view with prosthetic aortic and mitral valves. Prosthetic AV-Prosthetic Aortic valve, Prosthetic MV-Prosthetic Mitral Valve, LAA- Left atrial Appendage. (c): Midesophageal aortic valve short-axis view on transesophageal echocardiography with native aortic valve. RA – Right atrium, LA– Left atrium, NCC – Non coronary cusp, RCC – Right coronary cusp, LCC – Left coronary cusp, RV – Right ventricle, AV – Aortic valve. (d): Midesophageal aortic valve short-axis view on transesophageal echocardiography with prosthetic aortic valve. RA – Right atrium, LA – Left atrium, RV – Right ventricle, Prosthetic AV – Prosthetic aortic valveThe prosthetic aortic valve can be evaluated by TEE imaging in short and long-axis views. The aortic valve long-axis views have an inherent limitation of only imaging two opposite points of the prosthetic ring and, therefore, may fail to detect jets originating outside the imaging plane. However, in the aortic valve short-axis view, the entire circumference of the sewing ring can be imaged so that PVLs can be localized accurately.[5] In the aortic valve short-axis view on TEE, the NCC and LCC commissure appears at the upper middle part of the screen, corresponding to 6 o’clock on the surgeon’s view [Figure 1c and d]. We hope that the proposed schematic clock diagram for the aortic valve will aid in accurately locating PVLs just like the schematic clock diagram for the mitral valve. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.