When to consider cardiovascular magnetic resonance in patients undergoing transcatheter aortic valve replacement?

White paper on mitigating risk factors for acute kidney injury in TAVR: A protocol to decrease TAVR-associated AKI

Acute kidney injury (AKI) after transcatheter aortic valve replacement (TAVR) portends a poor prognosis. In the TVT registry, AKI after TAVR occurred in 10% of the patients. The etiology of AKI after TAVR is multifactorial but contrast volume remains one of the few modifiable risk factors. As patients referred for TAVR have multiple touch points within a siloed healthcare system, there remains an unmet clinical need of a well-defined clinical pathway to minimize the risk of AKI from the time of referral for TAVR to the completion of the procedure. This white paper aims to provide such a clinical pathway.

Preoperative TAVR Planning: How to Do It

Transcatheter aortic valve replacement (TAVR) is a well-established treatment option for patients with severe symptomatic aortic stenosis (AS) whose procedural efficacy and safety have been continuously improving. Appropriate preprocedural planning, including aortic valve annulus measurements, transcatheter heart valve choice, and possible procedural complication anticipation is mandatory to a successful procedure. The gold standard for preoperative planning is still to perform a multi-detector computed angiotomography (MDCT), which provides all the information required. Nonetheless, 3D echocardiography and magnet resonance imaging (MRI) are great alternatives for some patients. In this article, we provide an updated comprehensive review, focusing on preoperative TAVR planning and the standard steps required to do it properly.

Cardiac structural changes after transcatheter aortic valve replacement: systematic review and meta-analysis of cardiovascular magnetic resonance studies

BACKGROUND

Transcatheter aortic valve replacement (TAVR) is increasingly used to treat patients with severe aortic stenosis (AS). Cardiovascular magnetic resonance imaging (CMR) provides reliable and reproducible estimates for assessment of cardiac structure and function after TAVR. The goal of this study was to conduct a systematic review and meta-analysis of the literature to assess left ventricular (LV) volumes, mass and function by CMR after TAVR.

METHODS

Using Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines, we searched PubMed and Embase for studies reporting CMR findings before and at least 1 month after TAVR. Main factors of interest were LV end-diastolic volume index (LVEDVi), LV end-systolic volume index (LVESVi), LV mass index (LVMi), and left ventricular ejection fraction (LVEF). Standardized mean differences (SMD) were pooled by random effects meta-analytic techniques.

RESULTS

Of 453 screened publications, 10 studies (published between 2012 and 2018) were included. A total of 305 patients completed pre- and post-TAVR follow-up CMR (mean age range 78.6-85.0 years, follow-up range 6-15 months). Random effects analysis showed TAVR resulted in reduced LVEDVi (SMD: -0.25, 95% CI: - 0.43 to - 0.07, P = 0.006), LVESVi (SMD: -0.24, 95% CI: - 0.44 to - 0.05, P = 0.01), LVMi (SMD: -0.82, 95% CI: - 1.0 to - 0.63, P < 0.001) and increased LVEF (SMD: 22, 95% CI: 6 to 38%, P = 0.006). Heterogeneity across studies was low (I2: 0%, Pheterogeneity > 0.05 for all). The median reduction was 4 ml/m2 (IQR: 3.1 to 8.2) for LVEDVi, 5 ml/m2 (IQR: 3.0 to 6.0) for LVESVi, and 15.1 g/m2 (IQR: 11.8 to 18.3) for LVMi. The median increase for LVEF was 3.4% (IQR 1.0 to 4.6%).

CONCLUSIONS

CMR demonstrates reverse LV remodeling occurrs within 6-15 months after TAVR, with reductions in LVEDVi, LVESVi and LVMi, and increased LVEF.

MRI evaluation prior to Transcatheter Aortic Valve Implantation (TAVI): When to acquire and how to interpret

Transcatheter Aortic Valve Implantation (TAVI) is increasingly being used in patients with severe aortic stenosis who are not candidates for surgery. ECG-gated CT angiography (CTA) plays an important role in the preoperative planning for these devices. As the number of patients undergoing these procedures increases, a subset of patients is being recognized who have contraindications to iodinated contrast medium, either due to a prior severe allergic type reaction or poor renal function. Another subgroup of patients with low flow and low gradient aortic stenosis is being recognized that are usually assessed for severity of aortic stenosis by stress echocardiography. There are contraindications to stress echocardiography and some of these patients may not be able to undergo this test. Non-contrast MRI can be a useful emerging modality for evaluating these patients. In this article, we discuss the emerging indications of non-contrast MRI in preoperative assessment for TAVI and describe the commonly used MRI sequences. A comparison of the most important measurements obtained for TAVI assessment on CTA and MRI from same subjects is included. Teaching Points • MRI can be used for preoperative assessment of aortic annulus. • MRI is an alternate to CTA when iodinated contrast is contraindicated. • Measurements obtained by non-contrast MRI are similar to contrast enhanced CTA. • MRI can be used to assess severity of aortic stenosis.