Introduction Cardiac biomarker release is ubiquitous following surgical and trans-catheter aortic valve replacement (SAVR and TAVI), preventing accurate discrimination between release due to focal myocardial infarction (MI) and global myocardial injury (Figure 1). Furthermore, the need for peri-procedural revascularisation in TAVI is debated. Cardiovascular magnetic resonance (CMR) late gadolinium enhancement imaging (LGE) is the most sensitive imaging method to detect post-procedural new MI. Our study aimed to compare rates of new MI using CMR LGE before and 6m after TAVI and SAVR.
Methods Ninety six patients with severe aortic stenosis undergoing TAVI (n = 57) and SAVR (n = 39) were prospectively recruited and identical scans performed prior to (median 1 day) and 6m following aortic valve replacement. The presence of significant coronary artery disease (CAD) was determined by the occurrence of a >50% stenosis in any major epicardial vessel. Areas of LGE were quantified with computer-assisted planimetry (2SD; cmr42, Circle CVI). Presence of new LGE was determined by direct comparison of pre and post-procedure scans.
Results The SAVR group was younger, less symptomatic, had less 3 vessel CAD and were at lower surgical risk than the TAVI group. Most (87%) SAVR implants were bioprosthetic and most TAVI implants were Medtronic CoreValve (79%) (86% Transfemoral). Thirty-four (60%) patients had non-revascularised CAD at the time of TAVI. MI pattern LGE was present at baseline in 24 TAVI (42%) and 9 SAVR (24%) patients. The rate of new MI was greater in the SAVR group than the TAVI group (SAVR, n = 10 (26%) vs. TAVI, n = 3 (5%), p = 0.004). Absolute mean mass of new MI was similar between groups (SAVR 1.1g ± 0.6g vs. TAVI 2.0g ± 1.4g, p = 0.395) as was infarct mass as a percentage of left ventricular mass (SAVR 1.0 ± 0.4% vs. TAVI 2.2 ± 1.3%, p = 0.268) (Figure 2). None of the SAVR and only one of the TAVI infarcts were detected clinically (Figure 1 – blue dot). 34 patients (60%) in the TAVI group had non-revascularised CAD at the time of TAVI, of whom only 3 (9%) had new MI. In the SAVR group, 16 patients (41%) underwent concurrent coronary artery bypass grafting (CABG). Patients undergoing CABG were less likely to have a new MI than those not requiring concurrent revascularisation (CABG 6.3% vs. no CABG 39.1%, p = 0.021). There was no difference in mean cardiopulmonary bypass time (New MI 88.5 ± 31.1 vs. No new MI 114.5 ± 47.4min, p = 0.112) and aortic cross clamp time according to LGE status (New MI 66 ± 25 vs. No New MI 84 ± 42min, p = 0.164).
Conclusions MI is an infrequent complication of TAVI but is more common following SAVR. Infarct size is small following both procedures. The low new infarct rate in TAVI, especially in the context of high rates of non-revascularised CAD, is reassuring and strengthens the notion that coronary revascularization prior to TAVI may be unnecessary.
- Aortic Valve Replacement
- Myocardial Infarction
- Cardiovascular Magnetic Resonance
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