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/ AVBIII) and permanent pacemaker implantation (PPI) in surgical aortic valve replacement (SAVR).

METHODS: We retrospectively analysed preoperative contrast-enhanced MDCT scans and procedural outcomes of patients affected by aortic valve stenosis who underwent SAVR at our centre (06/2016-12/2019). The study population was divided into two groups (AVB, nonAVB) and variables were compared with a Mann-Whitney-U-test or Χ2 test. Data were further analysed using point-biserial correlation, logistic regression, and Kaplan Meier.

RESULTS: A total of 155 (38% female) patients, mean age 71.2±6 years were enrolled in our study: conventional stented bioprosthesis (N=99), sutureless prosthesis (N=56). A postoperative AVBIII was observed in 11 patients (7.1%). AVB patients had significant greater calcifications in left coronary cusp (LCC) AV (nonAVB=181.0mm3 (82.7-316.9) vs AVB=424.8mm3 (115.9-563.2), p=0.044), LCC left ventricular outflow tract (LVOT) (nonAVB=2.1mm3 (0-20.1) vs AVB=26.0mm³ (0.1-138.0), p=0.048), right coronary cusp (RCC) LVOT (nonAVB=0mm³ (0-3.5) vs AVB=2.8mm3 (0-29.0), p=0.039) and consequently in Total LVOT (nonAVB=2.1mm3 (0-20.1) vs AVB=26.0mm³ (0.1-138.0), p=0.02) while their MIS was significantly shorter than in nonAVB patients (nonAVB=11.3mm (9.9-13.4) vs AVB=9.44mm (6.98-10.5). 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 a MDCT in preoperative diagnostic testing for all patients undergoing surgical AVR for further risk stratification.