Cardiovascular Computed Tomography Aortic Valve Calcification, Myocardial Fibrosis And Adverse Outcome Following Transcatheter Aortic Valve Replacement

Introduction: There is evidence to suggest that subtype of aortic stenosis (AS), degree of myocardial fibrosis (MF) and level of aortic valve calcification (AVC) are associated with adverse cardiac outcome in AS. Since little is known about their respective contribution, we sought to investigate their relative importance and interplay as well as association with adverse cardiac events. Methods: 100 consecutive patients with severe AS and indication for transfemoral transcatheter aortic valve replacement (TAVR) were prospectively enrolled between January 2017 and October 2018. Patients underwent transthoracic echocardiography, multi detector computed tomography (MDCT) and left ventricular endomyocardial biopsy at the time of TAVR. Results: The final study cohort consisted of 92 patients with completed study protocol comprising of 39 (42.4 %) normal ejection fraction high gradient (NEFHG), 13 (14.1 %) low EF high gradient (LEFHG), 25 (27.2 %) low EF (flow) low gradient (LEFLG) and 15 (16.3 %) paradoxical low flow low gradient (PLFLG) AS. The high gradient phenotype (NEFHG and LEFHG) showed the largest amount of AVC (807 ± 421; 813 ± 281 mm 3 respectively) as compared to the low gradient phenotype (LEFLG and PLFLG; 503 ± 326; 555 ± 594 mm 3 respectively, p<0.05). Conversely, MF was most prevalent in low output phenotypes (LEFLG>LEFHG>PLFLG>HEFHG, p<0.05). This was paralleled by larger cardiovascular mortality within 400 days post TAVR (LEFLG n=7>PLFLG n=4>LEFHG n=2>NEFHG n=1). Within LEFLG AS, patients with larger AVC (>476.8 mm 3 ) had larger MF (40.2%) and higher cardiovascular mortality (n=5) as compared to patients with less AVC (≤476.8 mm 3 , 17.1% MF, p=0.027, cardiovascular mortality n=2). Conclusion: MF is associated with adverse cardiovascular outcome following TAVR which is most prevalent in low ejection fraction situations. Within the low ejection fraction low gradient subtype large AVC was associated with high amounts of MF and adverse cardiovascular outcome.