Prognostic impact of echocardiographic mean transvalvular gradients in patients with aortic stenosis and low flow undergoing transcatheter aortic valve implantation

BACKGROUND

Blunted left ventricular hemodynamics reflected by a low stroke volume index (SVI) ≤35 mL/m² body surface area (low flow [LF]) in patients with severe aortic stenosis (AS) are associated with worse outcomes even after correction of afterload by transcatheter aortic valve implantation (TAVI). These patients can have a low or high transvalvular mean pressure gradient (MPG). We investigated the impact of the pre-interventional MPG on outcomes after TAVI.

METHODS

Patients with LF AS were classified into those with normal (EF ≥ 50%; LF/NEF) or reduced ejection fraction (EF < 50%; LF/REF) and were then stratified according to an MPG < or ≥ 40 mmHg. Patients with SVI >35 mL/m² (normal flow; NF) served as controls.

RESULTS

597 patients with LF/NEF, 264 patients with LF/REF and 975 patients with NF were identified. Among all groups those patients with a low MPG were characterized by higher cardiovascular risk. In patients with LF/REF, functional improvement post-TAVI was less pronounced in low-MPG patients. One-year survival was significantly worse in LF AS patients with a low vs. high MPG (LF/NEF 16.5% vs. 10.5%, p = 0.022; LF/REF 25.4% vs. 8.0%, p = 0.002), whereas no differences were found in NF patients (8.7% vs. 10.0%, p = 0.550). In both LF AS groups, a low pre-procedural MPG emerged as an independent predictor of mortality.

CONCLUSIONS

In patients with LF AS, an MPG cut-off of 40 mmHg defines two patient populations with fundamental differences in outcomes after TAVI. Patients with LF AS and a high MPG have the same favorable prognosis as patients with NF AS.

Effective Orifice Area of Balloon-Expandable and Self-Expandable Transcatheter Aortic Valve Prostheses: An Echo Doppler Comparative Study

Published data on the size-specific effective orifice area (EOA) of transcatheter heart valves (THVs) remain scarce. Here, we sought to investigate the intra-individual changes in EOA and mean transvalvular aortic gradient (MG) of the Sapien 3 (S3), CoreValve (CV), and Evolut R (EVR) prostheses both at short-term and at 1-year follow-up. The study sample consisted of 260 consecutive patients with severe aortic stenosis who underwent transcatheter aortic valve implantation (TAVI). EOAs and MGs were measured with Doppler echocardiography for the following prostheses: S3 23 mm (n = 74; 28.5%), S3 26 mm (n = 67; 25.8%), S3 29 mm (n = 20; 7.7%), CV 23 mm (n = 2; 0.8%), CV 26 mm (n = 15; 5.8%), CV 29 mm (n = 24; 9.2%), CV 31 mm (n = 9; 3.5%), EVR 26 mm (n = 22; 8.5%), and EVR 29 mm (n = 27; 10.4%). Values were obtained at discharge, 1 month, 6 months, and 1 year from implantation. At discharge, EOAs were larger and MGs lower for larger-size prostheses, regardless of being balloon-expandable or self-expandable. In patients with small aortic annulus size, the hemodynamic performances of CV and EVR prostheses were superior to those of S3. However, we did not observe significant differences in terms of all-cause mortality according to THV type or size. Both balloon-expandable and self-expandable new-generation THVs show excellent hemodynamic performances without evidence of very early valve degeneration.

Comprehensive assessment of the aortic valve in critically ill patients for the non-cardiologist. Part I: Aortic stenosis of the native valve

Aortic stenosis (AS) causes left ventricular outflow obstruction. Severe AS has major haemodynamic implications in critically ill patients, in whom increased cardiac output and oxygen delivery are often required. Transthoracic echocardiography (TTE) plays a key role in the AS severity grading. In this review, we will give an overview of how to use the simplified Bernoulli equation to convert the echo Doppler measured velocities (cm s-1) to AS peak and mean gra-dient (mm Hg) and how to calculate the aortic valve area (AVA), using the continuity equation, based on the principle of preservation of flow. TTE allows quantification of compensatory left ventricular (LV) hypertrophy, assessment of LV systolic function, and determination of LV diastolic function and LV loading. Subsequently, the obtained results from the TTE study need to be integrated to establish the AS severity grading. The pitfalls of echocardiographic AS severity assessment are explained, and how to deal with inconsistency between AVA and mean gradient. The contribution of transoesophageal echocardiography, low-dose dobutamine stress echo (in case of low-flow low-gradient AS), echocardiography strain imaging, cardiac magnetic resonance imaging, cardiac multidetector computed tomography and the relatively new concept of Flow Pressure Gradient Classification to the work-up for aortic stenosis is discussed. Finally, the treatment of AS is overviewed. Elective aortic valve replacement is indicated in patients with severe symptomatic AS. In the ICU, afterload reduction by vasodilator therapy and treatment of pulmonary and venous congestion by diuretics could be considered.

Transcatheter valve-in-valve implantation in degenerated aortic bioprostheses: are patients with small surgical bioprostheses at higher risk for unfavourable mid-term outcomes?

Background

To examine outcomes of valve-in-valve (ViV) transcatheter aortic valve implantation (TAVI) according to the inner diameter (ID) of the degenerated aortic valve bioprosthesis.

Methods

We analyzed survival, stroke, permanent pacemaker (PPM) implantation, paravalvular (PV) leakage, acute kidney injury and vascular complications in fifty-nine patients during a ten-year period. Patients were stratified according to the ID of the indwelling degenerated biological aortic valve (true ID ≤ and >20 mm). Differences in post-procedural transvalvular gradients and hospital re-admissions were analyzed.

Results

The median age of the small diameter group and large diameter group was eighty-one and eighty years, respectively. Median logistic EuroSCORE I was 23.9% and 26.2% and median Society of Thoracic Surgeons (STS) score was 5.7% and 7.8% for the small and large groups, respectively. Survival, stroke, PPM implantation, PV leakage, acute kidney injury and vascular complications did not reach any statistically significant difference between both groups. Postprocedural transvalvular gradients differed significantly according to the true ID of the degenerated bioprosthetic valve and consequently of the respective TAVI valve. There was a significant difference with regard to hospital readmissions according to the true ID.

Conclusions

TAVI ViV implantation for aortic bioprostheses with small true IDs of ≤20 mm is associated with comparable mid-term mortality and periprocedural stroke rate compared to implantation into larger bioprostheses. However, the periprocedural and mid-term transvalvular gradients, as well as hospital re-admission rates are significantly higher in the small diameter group.

Effective orifice area and hemodynamic performance of the transcatheter Edwards Sapien 3 prosthesis: short-term and 1-year follow-up

Aims

The Edwards Sapien 3 heart valve prosthesis (S3) is commonly used for transcatheter aortic valve implantation (TAVI) and is available in three sizes. To date no data has been published on the effective orifice area (EOA) and the hemodynamic performance of the three different S3 sizes. The aim of this study was to measure the size-specific EOA and hemodynamic performance of the S3 in short-term and 1-year follow-up.

Methods and results

One hundred and thirteen consecutive patients treated by TAVI with a S3 prosthesis at the Heart Clinic Zurich between May 2014 and July 2015 were included. Clinical data were extracted from the Swiss TAVI registry. The EOA was calculated using Doppler echocardiography (peri-interventionally and at discharge) and by 3D-biplane transoesophageal echocardiography (peri-interventionally). Mean transvalvular gradients (dPmean) were additionally calculated with Doppler echocardiography at 30 days and 1 year. Results were analysed separately for the 23 mm (n = 42; 37%), 26 mm (n = 46; 41%), and 29 mm (n = 25; 22%) prostheses. At discharge, the EOAs were 1.6 ± 0.2 cm2 (23 mm S3), 2.0 ± 0.2 cm2 (26 mm S3), and 2.7 ± 0.2 cm2 (29 mm S3), p < 0.001. The dPmeans at discharge were 10.9 ± 6.0 mmHg (23 mm S3), 10.4 ± 3.5 mmHg (26 mm S3), and 8.9 ± 2.8 mmHg (29 mm S3), p = 0.235, and did not significantly change over time within any of the S3 sizes.

Conclusions

Post-TAVI, the EOAs of the three different S3 prosthesis sizes differ significantly, the transvalvular gradients, however, are comparable. Mean transvalvular gradients remain stable over time and document good prosthesis function after 1 year.

Trifecta has lower gradient and less prosthesis-patient mismatch than Mosaic Ultra in the aortic position: A prospective randomized study

OBJECTIVE

When aortic valve replacement is needed, a biological valve is usually implanted in patients older than age 60 to 65 years. A large valvular opening area is important to avoid prosthesis-patient mismatch and facilitate reverse left ventricular remodeling. The Trifecta biological valve (St Jude Medical, St Paul, Minn) is, because of its design, believed to reduce transvalvular gradient compared with other biological valves, especially in smaller annuli. Several retrospective studies have compared transvalvular gradients of implanted valves prostheses using the respective manufacturers given size and not the actual annulus size measured by a metric sizer. This makes comparison of the hemodynamic properties of different valve brands and sizes difficult. We therefore performed a prospective randomized study, using the same metric sizer to measure annulus size, and compared hemodynamic profiles of the Trifecta to our standard Mosaic Ultra biological valve (Medtronic, Minneapolis, Minn).

METHODS

Ninety elective patients with small to medium annulus diameter undergoing aortic valve replacement were randomized to either Trifecta or Mosaic Ultra. After native valve removal and decalcification, a Hegar-sizer was used to measure true annulus size. Then the largest possible valve of either brand was implanted according to the randomization protocol. Echocardiography was performed 6 months postoperatively.

RESULTS

Baseline parameters of the 2 cohorts were comparable. There were lower transvalvular gradients in the Trifecta compared with the Mosaic Ultra group for the given annulus sizes. Severe prosthesis-patient mismatch was present in 28% of patients in the Mosaic group and 3% of patients in the Trifecta group.

CONCLUSIONS

Trifecta showed lower transvalvular gradients and less severe prosthesis-patient mismatch compared with Mosaic Ultra for the given annulus sizes. ClinicalTrials.gov Protocol ID: 2011/2596/REK.

The effects of 21 and 23 milimeter aortic valve prosthesis on hemodynamic performance and functional capacity in young adults

OBJECTIVE

Early and medium-term improvement of functional capacity and regression of left ventricular hypertrophy was evaluated in the young adult patient group following application of 21 mm or 23 mm bileaflet aortic mechanical valve prosthesis due to aortic stenosis. Methods : Twenty two patients (10 male, 12 female; mean age 27+-8.2 (19-43)) who underwent isolated aortic valve replacement due to rheumatic aortic stenosis, were included in the study. 21 mm and 23 mm bileaflet mechanical prosthesis was used respectively in eight and fourteen patients. The mean body surface area was 1.86 m(2) and 1.68 m(2) respectively in 23 mm and 21 mm prosthesis while 1.73 ±0.25 m(2) for the whole group. Functional capacity was New York Heart Association (NYHA) class II in 9 patients and class III in thirteen patients. Implantation was performed without enlarging the aortic root in all except four patients. In all patients transvalvular gradients, effective orifice area and the diameter of left ventricle were measured with transthoracic echocardiography during rest and after maximal exercise. Mean follow-up was 34±12 months (range 11-57 months).

RESULTS

There were no postoperative complications or deaths. All the patients were assessed as NYHA class I with regards to functional capacity (p=0.01). Significant improvements were determined in postoperative mean transvalvular gradient (p=0.005) and left ventricular mass index (p=0.01) when compared with preoperative values.

CONCLUSION

Our findings show that replacement with 21 mm and 23 mm mechanical prosthesis provides a significant improvement in regression of symptoms and increase of functional capacity in young adults in early and mid-period without increasing mortality and morbidity.