The Implication of Preoperative Computed Tomography Angiography for Surgical Aortic Valve Replacement
Shinichi Fukuhara*, Taichi Suzuki, Karen Kim, Himanshu Patel, Bo Yang
Cardiac Surgery, University of Michigan, Ann Arbor, MI
Dedicated computed tomography angiography (CTA) has been the standard imaging tool prior to transcatheter aortic valve replacement (TAVR). However, the role of TAVR CTA for surgical aortic valve replacement (SAVR) is almost unknown. We aimed to evaluate the utility of CTA and its clinical implication in patients undergoing a SAVR.
Between 2014 and 2022, 1503 consecutive SAVR procedures were performed. The rates of aortic root enlargement and preoperative TAVR CTA prior to SAVR increased over time from 5.4% and 4.7% in 2014 to 50.0% and 59.6% in 2022, respectively. Among 466 patients with TAVR CTA, 93 patients were excluded due to previous SAVR (n=76) and/or TAVR (n=4), stentless (n=25), mechanical (n=4) or rarely used stented prosthesis (n=1) implantation (duplication counted), yielding the final cohort of 373 patients who received two most commonly used stented bioprostheses with similar valve dimensions.
Median age was 68.0 years, 37.0% were female and 36.2% had a bicuspid valve. SAVR implantation techniques comprised no aortic root enlargement (n=239; 64.1%), conventional root enlargement (n=72; 19.3%) and novel root enlargement (n=62; 16.6%) with corresponding median implanted valve size of 25.0 mm (interquartile range [IQR] 25.0-27.0), 23.0 mm (IQR 23.0-25.0), and 27.0 mm (IQR 25.0-29.0) (p< 0.001), and significant prosthesis-patient mismatch (PPM) rate of 35.5%, 43.1% and 6.5%, respectively (p< 0.001). Compared with CTA perimeter-derived annulus diameter, implanted labeled valve size during SAVR was almost always smaller in patients with no root or conventional root enlargement, whereas significantly larger with novel root enlargement (Figure 1A). Based on the CTA parameters, theoretical suitable TAVR valve in each patient was determined using both self-expandable and balloon-expandable devices. Of these, 57 (15.3%) patients for self-expandable and 54 (14.5%) patients for balloon-expandable device were deemed anatomically unsuitable. Among patients with suitable TAVR anatomy, significant PPM was seen in 8.3% (theoretical self-expandable device) and 41.6% (theoretical balloon-expandable device). In the subgroup analysis of SAVR/theoretical TAVR comparison, novel root enlargement was the only option that demonstrated a lower PPM rate compared with theoretical self-expandable TAVR (3.2% vs. 20.0%; p=0.008) (Figure 1B).
Preoperative TAVR CTA and aortic root enlargement rates are steeply rising, considering the lifetime management of aortic valve disease. Implantable stented bioprosthesis size during SAVR procedure is much smaller than expected, but the risk of clinically relevant PPM and necessity of aggressive root enlargement can be predicted utilizing preoperative TAVR CTA, which may have a long-term favorable implication. Additionally, SAVR with novel root enlargement technique in experienced hands outperforms even self-expandable TAVRs regarding PPM occurrence, while the aortic root anatomy is optimized for future valve-in-valve TAVR.
(A) The relationship between computed tomography angiography (CTA) perimeter-derived aortic annulus diameter and implanted valve size. The labeled size of implanted valve was almost always smaller than the CTA annulus measurement with no root enlargement or conventional root enlargement. Novel root enlargement achieved implantation of larger valve size than the CTA annulus measurement in all patients. (B) Proportion of significant prosthesis patient mismatch (PPM) was significantly higher with no root enlargement or conventional root enlargement. Novel root enlargement technique outperformed CTA-derived theoretical self-expandable TAVR regarding PPM occurrence.
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