Immediate Reduction in Left Ventricular Wall Stress Post Transcatheter Aortic Valve Replacement

Abstract

Background: Patients with aortic stenosis (AS) may have other competing comorbidities to account for their symptoms. Left ventricular wall stress (LVWS) is increased in patients with severe AS and is likely to be an indicator of AS severity, however the immediate effects of transcatheter aortic valve replacement (TAVR) have not been documented. We assessed acute changes in LVWS post TAVR. Methods: Six patients (median age 82 years (IQR 81.8–84)) undergoing TAVR for severe, symptomatic AS (median AV V max: 4.1 m/s (3.8–4.4), AVA 0.7 cm2 (0.68–0.85)) underwent MRI within 24 hours prior to TAVR. CMR-derived volumes were integrated with invasive haemodynamic data obtained using conductance catheters, to construct pressure-volume (PV) loops immediately before and after valve implantation. Pressures obtained on PV-loops were used to derive regional end-systolic (ES) and end-diastolic (ED) LVWS pre- and post-intervention (for 7 contiguous SAX planes). Results: TAVR was associated with a significant reduction in average ES-LVWS (7.8 to 5.7 × 103 N/m2, p = 0.046). There was a non-significant trend to suggest a reduction in median LV-ESP (133 mmHg pre, 129 mmHg post, p = 0.6), LV-EDP (15 mmHg pre, 13 mmHg post, p = 0.46) as well as a trend to suggest a reduction in maximum regional ES-LVWS (9.8 to 9.2 × 103 N/m2, p = 0.5) and minimum regional ES-LVWS (5.6 to 4.9 × 103 N/m2, p = 0.46). In contrast there was no significant change in ED-LVWS following TAVR (average ED-LVWS 2.3 to 2.3, p = 0.46, maximum ED-LVWS 2.6–2.8 × 103 N/m2, p = 0.46). Conclusion: In patients with severe, symptomatic AS, TAVR is associated with an immediate reduction in end-systolic wall stress, however end-diastolic wall stress is unchanged.