The emerging applications of cardiovascular magnetic resonance imaging in transcatheter aortic valve implantation

Multiparametric Outcome Assessment After Transcatheter Aortic Valve Implantation-A Systematic Review

Backround/Objectives: Aortic stenosis (AS) is the most commonly acquired valvular disorder. Patient risk stratification and the development of an accurate and reliable tool are crucial in identifying suitable candidates for TAVI. The present review summarized the current state of knowledge on the influence of selected factors on the outcomes and course of patients with AS undergoing transcatheter aortic valve implantation (TAVI). Methods: The inclusion criteria for the present systematic review were as follows: (1) studies indexed in the medical databases PubMed, MEDLINE, EMBASE, CINAHL, Web of Science, and Scopus; (2) full-text articles available in English; (3) papers published between 2013 and 2023; and (4) addressing the topic of assessing the impact of factors on the outcomes of patients with aortic stenosis undergoing TAVI. This review used PRISMA 2020 reporting guidelines for systematic reviews and meta-analyses. Results: One hundred and thirty-two studies were eligible for this review. The available studies showed an association of psychosocial and socioeconomic factors, valve parameters, comorbidities, clinical factors, treatment-related factors, biomarkers, and treatment methods with the outcomes of patients with AS undergoing TAVI. Conclusions: Given the conflicting results obtained regarding the impact of right ventricular dysfunction, paravalvular leaks, and treatment method on the mortality of patients undergoing aortic valve implantation, further research in these areas is needed. In view of the researchers' differing views on some of the factors affecting patient outcomes after TAVI, further analysis is needed to develop a new tool for assessing predictive outcomes in AS patients. This study is registered at PROSPERO (CRD42024612752).

Compliant Aortic Annulus Sizing With Different Elliptical Ratios Through a Valvuloplasty Balloon Catheter

OBJECTIVE

Aortic stenos (AS) is a heart valve disease that commonly affects the elderly. Transcatheter aortic valve implantation is a minimally invasive treatment that allows to replace the function of the diseased native valve with a prosthetic device, relying on catheters for device implantation. According to the current clinical guidelines, the choice of the implanted device is based on preoperative sizing determined by image-based technology. However, this assessment faces inherent limitations that can lead to sub-optimal sizing of the prosthesis; in turn, this can cause major post-operative complications like aortic regurgitation or cardiac electrical signal disruption.

METHOD

By utilizing balloon pressure and volume data, this article proposes an intra-operative method for determining the dimension of the aortic annulus which takes into account its compliance and geometric irregularity. The intra-balloon pressure-volume curves were obtained using an Automated Balloon Inflation Device operating a commercially available valvuloplasty balloon catheter. A sizing algorithm to estimate the dimensions of the annulus was integrated via a validated analytical model and a numerical model for balloon free-inflation. Tests were performed on circular and elliptical idealised aortic phantoms.

RESULTS

Experimental results confirm that the pressure-volume data processed with the sizing algorithm can be used to determine the circular annular diameter for all tissue rigidities.

CONCLUSION

The measurement of stiffer elliptical annulus phantoms shows good accuracy and high repeatability.

SIGNIFICANCE

This work represents substantial progress toward improving the selection of TAVI devices by using balloon catheters to improve the sizing of compliant aortic annuli with complex geometry.

Quantification of paravalvular leaks associated with TAVI implants using 4D MRI in an aortic root phantom made possible by the use of 3D printing

Introduction

Transcatheter aortic valve implantation (TAVI) has become an alternative to surgical replacement of the aortic valve elderly patients. However, TAVI patients may suffer from paravalvular leaks (PVL). Detecting and grading is usually done by echocardiography, but is limited by resolution, 2D visualization and operator dependency. 4D flow magnetic resonance imaging (MRI) is a promising alternative, which did not reach clinical application in TAVI patients. The aim of this study was applying 3D printing technologies in order to evaluate flow patterns and hemodynamics of PVLs following TAVI, exploiting 4D flow MRI and standard ultrasound.

Materials and methods

An MR-compatible, anatomically left ventricle, aortic root, and ascending aorta model was fabricated by combining 3D-printed parts and various soft silicone materials to match physiological characteristics. An Abbott Portico™ valve was used in continuous antegrade flow (12-22 l/min), retrograde flow with varying transvalvular pressures (60-110 mmHg), and physiological pulsatile hemodynamics (aortic pressure: 120/80 mmHg, cardiac output: 5 l/min) Time-resolved MR measurements were performed above and below the TAVI stent and compared with color Doppler ultrasound measurements in exactly the same setup.

Results

The continuous antegrade flow measurements from MRI largely agreed with the flowmeter measurements, and a maximum error of only 7% was observed. In the retrograde configuration, visualization of the paravalvular leaks was possible from the MR measurements, but flow was overestimated by up to 33%. The 4D MRI measurement in the pulsatile setup revealed a single main PVL, which was also confirmed by the color Doppler measurements, and velocities were similar (2.0 m/s vs. 1.7 m/s).

Discussion

4D MRI techniques were used to qualitatively assess flow in a patient-specific, MR-compatible and flexible model, which only became possible through the use of 3D printing techniques. Flow patterns in the ascending aorta, identification and quantification of PVLs was possible and the location and extent of PVLs were confirmed by ultrasound measurements. The 4D MRI flow technique allowed evaluation of flow patterns in the ascending aorta and the left ventricle below the TAVI stent with good results in identifying PVLs, demonstrating its capabilities over ultrasound by providing the ability to visualize the paravalvular jets in three dimensions at however, additional expenditure of time and money.

[Role of magnetic resonance imaging in patients with aortic stenosis before and after replacement of the valve]

Risk stratification among patients with aortic stenosis remains inadequate, and there is a clinical need for the correct identification of high-risk patients who would benefit from aortic valve intervention before developing left ventricular decompensation. Since the publication of the results of the PARTNER study, transcatheter aortic valve implantation (TAVI) has become the method of choice for aortic valve stenosis in inoperable patients and is a real alternative to conventional surgical replacement of the aortic valve in high-risk patients. In planning TAVI and postoperative monitoring of a patient from imaging methods, the leading role is played by echocardiography and multispiral computed tomography. However, in recent years, the interest of researchers in the use of magnetic resonance imaging in this category of patients has increased. The review article examines the potential role of magnetic resonance imaging in patients with aortic stenosis before and after TAVI.

Cardiac-CT and cardiac-MR cost-effectiveness: a literature review

Cardiovascular diseases are still among the first causes of death worldwide with a huge impact on healthcare systems. Within these conditions, the correct diagnosis of coronary artery disease with the most appropriate imaging-based evaluations is of utmost importance. The sustainability of the healthcare systems, considering the high economic burden of modern cardiac imaging equipments, makes cost-effective analysis an important tool, currently used for weighing different costs and health outcomes, when policy makers have to allocate funds and to prioritize interventions, getting the most out of their financial resources. This review aims at evaluating cost-effective analysis in the more recent literature, focused on the role of Calcium Score, coronary computed tomography angiography and cardiac magnetic resonance.