Patients with severe aortic stenosis (AS) tend to develop concentric left ventricular (LV) hypertrophy due to continuous pressure overload. Transcatheter aortic valve implantation (TAVI) induces LV reverse remodelling caused by reduced wall stress and can be monitored by magnetic relaxation times using cardiovascular magnetic resonance (parametric CMR).

 

T2 mapping is an appropriate monitoring parameter for myocardial reverse remodelling and correlates with clinical outcome in patients who underwent TAVI.

 

The aim of this study was to investigate the impact of parametric CMR regarding T2 mapping on long-term myocardial tissue adaptations and clinical status after TAVI in two years follow-up.

From October 2017 to October 2020 a total of 20 patients with severe AS undergoing TAVI (aged 82.2±4.8 years) completed CMR before intervention (pre-TAVI), at 3-months (3-FU), 12-months follow-up (12-FU) and 24-months follow-up (24-FU) for assessment of myocardial remodelling by T2 mapping. Clinical status was compared by New York Heart Association (NYHA) class and 6-minutes walking test (6-MWT). Furthermore, patients were devided into two subgroups according to T2 time of 68.6 ms, which was the median of all T2 values in 24-FU. The high-T2 (≥68.6 ms; n=10) and the low-T2 subgroup (<68.6 ms; n=10) were compared in terms of clinical status again.

 

Results: 

After TAVI T2 relaxation times did not significantly decrease during 3-FU (pre-TAVI vs. 3-FU: 68.9±3.7 vs. 66.8±4.0 ms; p=0.7082), but remarkably decreased in 12-FU (pre-TAVI vs. 12-FU: 68.9±3.7 vs. 63.2±1.9 ms; p=0.0289) and even more in 24-FU (pre-TAVI vs. 24-FU: 68.9±3.7 vs. 61.6±2.6 ms; p=0.0013). A highly significant improvement of NYHA class could be observed in all patients (pre-TAVI vs. 24-FU: 2.5±0.7 vs. 1.2±0.5; p<0.0001), whereas 6-MWT distance only improved by tendency. Regarding the high-T2 and low-T2 subgroups during 24-FU, 6-MWT distance did not significantly change during follow-up in both groups, but patients in low-T2 subgroup tended to have longer 6-MWT distances than those in high-T2 during all follow-up examinations. The same observation could be made for NYHA class with less limitation of physical activity in low-T2 subgroup (low-T2 vs. high-T2: pre-TAVI 2.3±0.7 vs. 2.5±0.7; 24-FU 1.0±0.0 vs. 1.4±0.5; p=0.0386).

 

In patients who underwent TAVI, decreased T2 times over time assessed by parametric CMR are associated with LV reverse remodelling and clinical improvement in long-term follow-up of two years. In combination with clinical evaluation, CMR can monitor myocardial adaptation and guide further diagnostic and therapeutic action.