Baseline CT-Based Risk Factors for Atrioventricular Block after Surgical AVR

Background We aimed to evaluate the impact of membranous interventricular septum (MIS) length and calcifications of the native aortic valve (AV), via preoperative multidetector computed tomography (MDCT) scan, on postoperative atrioventricular block III (AVB/AVB III) and permanent pacemaker implantation in surgical aortic valve replacement (SAVR). Methods We retrospectively analyzed preoperative contrast- enhanced MDCT scans and procedural outcomes of patients affected by AV stenosis who underwent SAVR at our center (June 2016-December 2019). The study population was divided into two groups (AVB and non-AVB), and variables were compared with a Mann- Whitney ' s Utest or chi-square test. Data were further analyzed using point biserial correlation and logistic regression. Results A total of 155 (38% female) patients (mean age of 71.2 +/- 6 years) were enrolled in our study: conventional stented bioprosthesis (N = 99) and sutureless prosthesis (N = 56) were implanted. A postoperative AVB III was observed in 11 patients ( 7.1%). AVB patients had significant greater calcifications in left coronary cusp ( LCC) -AV ( non- AVB = 181.0mm(3) [82.7- 316.9] vs. AVB = 424.8mm(3) [115.9-563.2], p = 0.044), LCC left ventricular outflow tract (LVOT) (non-AVB = 2.1mm(3) [0-20.1] vs. AVB = 26.0 mm(3) [0.1-138.0], p = 0.048), right coronary cusp ( RCC) -LVOT (non-AVB = 0mm(3) [ 03.5] vs. AVB = 2.8mm(3) [0-29.0], p = 0.039), and consequently in total LVOT (nonAVB = 2.1mm(3) [0-20.1] vs. AVB = 26.0mm(3) [0.1-138.0], p = 0.02), while their MIS was significantly shorter than in non-AVB patients (non-AVB = 11.3mm [9.9-13.4] vs. AVB = 9.44mm [6.98-10.5]; p=0.014)). Partially, these group differences correlated positively (LCC-AV, r =0.201, p = 0.012; RCC- LVOT, r = 0.283, p = 0.001) or negatively ( MIS length, r = 0.202, p <= 0.008) with new-onset AVB III. Conclusion We recommend including an MDCT in preoperative diagnostic testing for all patients undergoing surgical AVR for further risk stratification.

Automated summary

This study aimed to evaluate the impact of membranous interventricular septum (MIS) length and calcifications of the native aortic valve (AV) on postoperative atrioventricular block III (AVB/AVB III) and permanent pacemaker implantation in surgical aortic valve replacement (SAVR). Preoperative multidetector computed tomography (MDCT) scans and procedural outcomes were retrospectively analyzed. The results showed that patients with AVB had more severe calcifications in specific areas and a shorter MIS length. Therefore, we recommend including MDCT in preoperative diagnostic testing to further stratify the risk for patients undergoing surgical AVR.