The impact of calcium volume and distribution in aortic root injury related to balloon-expandable transcatheter aortic valve replacement

Background A detailed assessment of calcium within the aortic root may provide important additional information regarding the risk of aortic root injury during transcatheter heart valve replacement (TAVR). Objective We sought to delineate the effect of calcium volume and distribution on aortic root injury during TAVR. Methods Thirty-three patients experiencing aortic root injury during TAVR with a balloon-expandable valve were compared with a control group of 153 consecutive TAVR patients without aortic root injury (as assessed by post-TAVR multidetector CT). Using commercial software to analyze contrast-enhanced pre-TAVR CT scans, calcium volume was determined in 3 regions: (1) the overall left ventricular outflow tract (LVOT), extending 10 mm down from the aortic annulus plane; (2) the upper LVOT, extending 2 mm down from the annulus plane; and (3) the aortic valve region. Results Calcium volumes in the upper LVOT (median, 29 vs 0 mm3; P < .0001) and overall LVOT (median, 74 vs 3 mm3; P = .0001) were higher in patients who experienced aortic root injury compared with the control group. Calcium in the aortic valve region did not differ between groups. Upper LVOT calcium volume was more predictive of aortic root injury than overall LVOT calcium volume (area under receiver operating curve [AUC], 0.78; 95% confidence interval, 0.69–0.86 vs AUC, 0.71; 95% confidence interval, 0.62–0.82; P = .010). Upper LVOT calcium below the noncoronary cusp was significantly more predictive of aortic root injury compared to calcium underneath the right coronary cusp or the left coronary cusp (AUC, 0.81 vs 0.68 vs 0.64). Prosthesis oversizing >20% (likelihood ratio test, P = .028) and redilatation (likelihood ratio test, P = .015) improved prediction of aortic root injury by upper LVOT calcium volume. Conclusion Calcification of the LVOT, especially in the upper LVOT, located below the noncoronary cusp and extending from the annular region, is predictive of aortic root injury during TAVR with a balloon-expandable valve.