Inverse Relationship Between Membranous Septal Length and the Risk of Atrioventricular Block in Patients Undergoing Transcatheter Aortic Valve Implantation.
OBJECTIVES
This study sought to examine whether imaging of the atrioventricular (AV) membranous septum (MS) by computed tomography (CT) can be used to identify patient-specific anatomic risk of high-degree AV block and permanent pacemaker (PPM) implantation before transcatheter aortic valve implantation (TAVI) with self-expandable valves.


BACKGROUND
MS length represents an anatomic surrogate of the distance between the aortic annulus and the bundle of His and may therefore be inversely related to the risk of conduction system abnormalities after TAVI.


METHODS
Seventy-three consecutive patients with severe aortic stenosis underwent contrast-enhanced CT before TAVI. The aortic annulus, aortic valve, and AV junction were assessed, and MS length was measured in the coronal view.


RESULTS
In 13 patients (18%), high-degree AV block developed, and 21 patients (29%) received a PPM. Multivariable logistic regression analysis revealed MS length as the most powerful pre-procedural independent predictor of high-degree AV block (odds ratio [OR]: 1.35, 95% confidence interval [CI]: 1.1 to 1.7, p = 0.01) and PPM implantation (OR: 1.43, 95% CI: 1.1 to 1.8, p = 0.002). When taking into account pre- and post-procedural parameters, the difference between MS length and implantation depth emerged as the most powerful independent predictor of high-degree AV block (OR: 1.4, 95% CI: 1.2 to 1.7, p < 0.001), whereas the difference between MS length and implantation depth and calcification in the basal septum were the most powerful independent predictors of PPM implantation (OR: 1.39, 95% CI: 1.2 to 1.7, p < 0.001 and OR: 4.9, 95% CI: 1.2 to 20.5, p = 0.03; respectively).


CONCLUSIONS
Short MS, insufficient difference between MS length and implantation depth, and the presence of calcification in the basal septum, factors that may all facilitate mechanical compression of the conduction tissue by the implanted valve, predict conduction abnormalities after TAVI with self-expandable valves. CT assessment of membranous septal anatomy provides unique pre-procedural information about the patient-specific propensity for the risk of AV block.
['Hamdan|Ashraf|A|', 'Guetta|Victor|V|', 'Klempfner|Robert|R|', 'Konen|Eli|E|', 'Raanani|Ehud|E|', 'Glikson|Michael|M|', 'Goitein|Orly|O|', 'Segev|Amit|A|', 'Barbash|Israel|I|', 'Fefer|Paul|P|', 'Spiegelstein|Dan|D|', 'Goldenberg|Ilan|I|', 'Schwammenthal|Ehud|E|']
D000368:Aged D000369:Aged, 80 and over D001021:Aortic Valve D001024:Aortic Valve Stenosis D054537:Atrioventricular Block D006328:Cardiac Catheterization D002304:Cardiac Pacing, Artificial D005260:Female D006346:Heart Septum D006350:Heart Valve Prosthesis D019918:Heart Valve Prosthesis Implantation D006801:Humans D016015:Logistic Models D008297:Male D061330:Multidetector Computed Tomography D015999:Multivariate Analysis D016017:Odds Ratio D011237:Predictive Value of Tests D018570:Risk Assessment D012307:Risk Factors D012720:Severity of Illness Index D016896:Treatment Outcome
atrioventricular block membranous septum CT permanent pacemaker TAVI implantation depth