Cardio–Splenic Relationship in Patients Receiving Trans-Catheter Aortic Valve Replacement

Figure 1. Measurement of splenic volume using abdominal computed tomography imaging. Spleen (green) in horizontal section was traced by the software in each slice (A). Three-dimensional image of spleen was displayed (B). SYNAPSE VINCENT software, version 2.0003, developed by Fujifilm in Tokyo, Japan, was used to measure splenic volume. Using the software’s preset algorithm for extracting elliptical tissue, the software automatically recognized the spleen when the long axis of the spleen was specified from a multi-slice computed tomography scan cross-sectional image (spleen was traced and colored in green in each slice). All the recognized splenic images were constructed in three dimensions and output as an image, and its splenic volume was automatically calculated. In cases where necessary, manual adjustments were made to the trace before arriving at the final measurements. For the independent variable, we indexed the value of splenic volume. R, right; L, left.

Figure 2. Distribution of splenic volume index obtained before transcatheter aortic valve replacement.

Figure 3. Representative cases of high splenic volume index (A) and low splenic volume index (B). Spleen was colored in green in horizontal section image and was colored in red in three-dimensional constructed image. (A) Patient 1 was 76-year-old woman. Body height was 160 cm and body weight was 72.3 kg. Her splenic volume index was calculated as 199.5 mL/m2. (B) Patient 2 was 86-year-old man. His body height was 161 cm and body weight was 76.8 kg. His splenic volume index was calculated as 35.5 mL/m2. Splenic volume was larger in patient 1 compared to patient 2 in both 2-dimensional and 3-dimenstional imaging. R, right; L, left.

Figure 4. Cutoff of splenic volume index to estimate the primary outcome. The primary outcome was defined as 2-year cardiac death or heart failure readmission. A cutoff of splenic volume index was calculated at 70.2 mL/m2 by receiver operating characteristics analysis and shown as a red circle in this curve. SVI, splenic volume index; HF, heart failure.

Figure 5. Cumulative incidence of the primary endpoint during 2-year observation period after the index discharge. Cumulative incidence was stratified into two groups by SVI at a cutoff of 70.2 mL/m2. A higher SVI was associated with greater cumulative incidence of the primary outcome. SVI, splenic volume index. The primary outcome was defined as cardiac death or heart failure readmission. * p < 0.05 by log-rank test.