Risk of Atrioventricular Block following Surgical Aortic Valve Replacement: A Computed Tomographic Analysis of Baseline Characteristics

Background: Postoperative complete atrioventricular block (AVB) is a frequent complication following surgical aortic valve replacement (SAVR). We aimed to determine the impact of anatomical variables and calcium load—assessed by preoperative multidetector computed tomography (MDCT) scan—to predict this outcome.

Method: From 2017 up to December 31, 2019, a preoperative MDCT was performed in patients affected by aortic valve stenosis for planning minimally invasive SAVR. Exclusion criteria were prior pacemaker implantation, endocarditis, prior valve interventions. Calcium load was calculated via 3mensio (Medical Imaging BV, the Netherlands). The study population was divided into two groups (AVB, non-AVB); baseline (clinical, echocardiogram, ECGs) and intraoperative characteristics were tested for normal distribution and compared with a no-parametric test (Mann–Whitney U-test) or Chi-square.

Results: A total of 155 (38% female) patients were included. Mean age was 71.2 ± 6 years, mean EuroSCORE II 2.8% ± 3. A total of 56 patients (36%) received a sutureless, while the rest a conventional bioprosthesis. A ministernotomy was performed in 109 patients (70%). A postoperative AVB was observed in 11 patients (7.1%), with higher but not significant prevalence in those who received a sutureless SAVR (10 vs. 5%; p = 0.2). The two groups were similar concerning mean age (non-AVB = 71.2 ± 6 vs. AVB = 70.9 ± 9 years; p = 0.8), EuroSCORE II (non-AVB = 2.8% ± 3 vs. AVB = 2.5% ± 1; p = 0.5), incidence of bicuspid valve (non-AVB = 31% vs. AVB = 27%; p = 0.8), CT-measured annulus area (non-AVB = 5 ± 1 vs. AVB = 5.4 ± 1 cm²; p = 0.3) and CT-measured membranous septum length (non-AVB = 12.6 ± 3 vs. AVB = 13.1 ± 2 mm; p = 0.6). Slight, but not significant differences were detected in LVEF (non-AVB = 57% ± 10 vs. AVB = 53.5% ± 12; p = 0.3) and right bundle branch block (non-AVB = 9% vs. AVB = 18%; p = 0.28). Calcium load and distribution differed significantly between groups, especially in the LVOT (see [Table]).

	Non-AVB	AVB	p-Value
Total AV calcium (mm3)	891.1 ± 624	1,239.0 ± 905	0.190
LCC calcium (mm3) AV	229.1 ± 193	386.2 ± 263	0.044
RCC calcium (mm3) AV	280.3 ± 263	432.8 ± 370	0.123
NCC calcium (mm3) AV	369.2 ± 291	419.1 ± 374	0.661
Total calcium LVOT (mm3)	66.0 ± 121	122.5 ± 130	0.02
LCC calcium LVOT (mm3)	33.5 ± 82	58.1 ± 62	0.048
RCC calcium LVOT (mm3)	6.2 ± 15	36.8 ± 89	0.039
NCC calcium LVOT (mm3)	26.3 ± 67	27.7 ± 26	0.116

Conclusion: Calcium load—as assessed by preoperative MDCT—was significantly higher in patients who developed a complete AVB following SAVR and thus is helpful in identifying patients at risk.

Publication History

Article published online:
03 February 2022