Björn Plicht

Cerebral Embolization During Transcatheter Aortic Valve Implantation A Transcranial Doppler Study

Background— Transcatheter aortic valve implantation (TAVI) is associated with a higher risk of neurological events for both the transfemoral and transapical approach than surgical valve replacement. Cerebral magnetic resonance imaging has revealed more new, albeit clinically silent lesions from procedural embolization, yet the main source and predominant procedural step of emboli remain unclear. Methods and Results— Eighty-three patients underwent transfemoral (Medtronic CoreValve [MCVTF], n=32; Edwards Sapien [ESTF], n=26) and transapical (ESTA: n=25) TAVI. Serial transcranial Doppler examinations before, during, and 3 months after TAVI were used to identify high-intensity transient signals (HITS) as a surrogate for microembolization. Procedural HITS were detected in all patients, predominantly during manipulation of the calcified aortic valve while stent valves were being positioned and implanted. The balloon-expandable ES prosthesis caused significantly more HITS (mean [95% CI]) during positioning (ESTF, 259.9 [184.8–334.9]; ESTA, 206.1[162.5–249.7]; MCVTF, 78.5 [25.3–131.6]; P<0.001) and the self-expandable MCV prosthesis during implantation (MCVTF, 397.1 [302.1–492.2]; ESTF, 88.2 [70.2–106.3]; ESTA, 110.7 [82.0–139.3]; P<0.001). Overall, there were no significant differences between transfemoral and transapical TAVI or between the MCV and ES prostheses. No HITS were detected at baseline or 3-month follow-up. There was 1 major procedural stroke that resulted in death and 1 minor procedural stroke with full recovery at 3-month follow-up in the MCV group. Conclusions— Procedural HITS were detected by transcranial Doppler in all patients. Although no difference was observed between the transfemoral and the transapical approach with the balloon-expandable ES stent valve, transfemoral TAVI with the self-expandable MCV prosthesis resulted in the greatest number of HITS, predominantly during implantation.

Direct Assessment of Size and Shape of Noncircular Vena Contracta Area in Functional Versus Organic Mitral Regurgitation Using Real-Time Three-Dimensional Echocardiography

BACKGROUND Vena contracta width (VCW) as an estimate of effective regurgitant orifice area (EROA) is an accepted parameter of mitral regurgitation (MR) severity. However, uncertainty exists in cases in which VCW at the same time appears narrow in 4-chamber (4CH) view and broad in 2-chamber (2CH) view as common in functional MR with noncircular or slit-like regurgitant orifices. We therefore hypothesized that new real-time 3-dimensional color Doppler echocardiography (RT3DE) can be used for direct assessment of the size and shape of vena contracta area (VCA) in an en face view and to determine the potential error of conventional VCW measurement on estimation of EROA. METHODS RT3DE was performed in 57 patients with relevant MR of different etiologies. Manual tracing of VCA in a cross-sectional plane through the vena contracta was compared with VCW in 4CH and 2CH views. As a comparative approach to VCA-3D, EROA was calculated using the hemispheric and hemielliptic proximal isovelocity surface (PISA) area method. RESULTS Direct measurement of VCA-3D was feasible in all patients within 2.6 +/- 0.7 minutes. RT3DE revealed significant asymmetry of VCA in functional compared with organic MR (P < .001). Among all patients, VCW-4CH and VCW-2CH correlated only moderately to VCA-3D (r =.77; r =.80). Mean VCW correlated and agreed best with VCA-3D (r =.90). VCA-3D correlated and agreed well with EROA by hemielliptic PISA (r = .96, mean error: -0.09 +/- 0.14 cm(2)) compared with significant underestimation of hemispheric PISA in noncircular lesions. CONCLUSIONS Direct assessment of VCA using RT3DE revealed significant asymmetry of VCA in functional MR compared with organic MR, resulting in poor estimation of EROA by single VCW measurements.

Acute outcomes after MitraClip therapy in highly aged patients: results from the German TRAnscatheter Mitral valve Interventions (TRAMI) Registry.

AIMS The influence of age on baseline demographics and outcomes of patients selected for MitraClip has not been previously investigated. METHODS AND RESULTS Baseline demographics and acute outcomes in 1,064 patients from the German TRAMI registry were stratified by age (525 patients ≥76 years and 539 patients <76 years). In elderly patients, logistic EuroSCORE was higher (25[15-40]% vs. 18[10-31]%, p<0.0001) and the proportion of women was greater (47.2% vs. 29.3%, p<0.0001). Elderly patients were more likely to have preserved left ventricular ejection fraction >50% (40.1% vs. 21.8%, p<0.0001) and degenerative mitral regurgitation (DMR, 35.3% vs. 25.6%, p<0.01). Age was the most frequent reason for non-surgical treatment in the elderly (69.4% vs. 36.1%, p<0.0001). The intrahospital MACCE (death, myocardial infarction, stroke) was low in both groups (3.5% vs. 3.4%, p=0.93) and the proportion of non-severe mitral regurgitation at discharge was similar (95.8% vs. 96.4%, p=0.73). A logistic regression model did not reveal any significant impact of age on acute efficacy and safety of MitraClip therapy. In both groups, the majority of patients were discharged home (81.8% vs. 86.2%, p=0.06). CONCLUSIONS Elderly and younger patients have similar benefits from MitraClip therapy. Age was the most frequent cause for denying surgery in elderly patients.

Intramural hematoma and penetrating ulcers: indications to endovascular treatment.

Intramural hematoma (IMH) of the aorta and penetrating aortic ulcer (PAU) are important variant forms of classic double-barrel aortic dissection in patients presenting with acute aortic syndrome. Recent insights provided by modern high-resolution imaging are currently challenging previous pathophysiologic concepts underlying IMH and PAU, suggesting a close relationship of both entities. Thoracic endovascular aortic repair (TEVAR) offers a less invasive approach to the treatment of affected patients with very encouraging early to midterm results. This review discusses current indication for TEVAR in IMH and PAU patients in the view of an improved understanding of these diseases.

Effect of dynamic flow rate and orifice area on mitral regurgitant stroke volume quantification using the proximal isovelocity surface area method.

OBJECTIVES This study sought to determine the effect of dynamic variations of mitral regurgitant flow rate (MRFR) and effective regurgitant orifice area (EROA) on mitral regurgitant stroke volume (MRSV) quantification using 4 different single-point and time-integral proximal isovelocity surface area (PISA) methods using magnetic resonance imaging (MRI) for reference. BACKGROUND Using PISA provides measures of MRFR, but calculating MRSV is challenging because of dynamic variations in the flow profile dependent on the underlying mechanism of mitral regurgitation (MR). Although various single-point and time-integral approaches have been described to overcome this limitation, uncertainty exists about the accuracy and feasibility of these methods in routine clinical practice. METHODS In 73 patients with MR of different etiologies, MRSV was calculated from an apical 4-chamber view using the following 4 hemispheric PISA methods: 1) PISA-velocity-time integral (VTI) = midsystolic MRFR by PISA x regurgitant flow VTI/peak velocity; 2) simplified PISA = midsystolic MRFR/3.25; 3) serial PISA = sum of instantaneous MRFRs over serial 2-dimensional frames; and 4) M-mode PISA = time-integral of MRFRs from color M-mode. The MRSV by MRI was calculated from mitral inflow minus aortic outflow. RESULTS Single-point PISA methods yielded greater underestimation of MRSV (mean error: -13.3 +/- 10.2 ml [PISA-VTI]; -13.5 +/- 10.3 ml [simplified PISA]), particularly in functional MR, compared with time-integral PISA methods accounting for variations of MRFR and EROA over time (mean error: -8.0 +/- 6.4 ml [M-mode PISA]; -8.7 +/- 7.4 ml [serial PISA]). CONCLUSIONS Depending on the underlying mechanism of MR, dynamic variations of MRFR and EROA revealed important limitations of MRSV calculation using single-point and time-integral PISA methods.

Measurement of the aortic annulus size by real-time three-dimensional transesophageal echocardiography.

Abstract We sought to determine the level of agreement and the reproducibility of two-dimensional (2D) transthoracic (2D-TTE), 2D transesophageal (2D-TEE) and real-time three-dimensional (3D) transesophageal echocardiography (RT3D-TEE) for measurement of aortic annulus size in patients referred for transcatheter aortic valve implantation (TAVI). Accurate preoperative assessment of the dimensions of the aortic annulus is critical for patient selection and successful implantation in those undergoing TAVI for severe aortic stenosis (AS). Annulus size was measured using 2D-TTE, 2D-TEE and RT3D-TEE in 105 patients with severe AS referred for TAVI. Agreement between echocardiographic methods and interobserver variability was assessed using the Bland-Altman method and regression analysis, respectively. The mean aortic annuli were 21,7 ± 3 mm measured with 2D-TTE, 22,6 ± 2,8 mm with 2D-TEE and 22,3 ± 2,9 mm with RT3D-TEE. The results showed a small but significant mean difference and a strong correlation between the three measurement techniques (2D-TTE vs. 2D-TEE mean difference 0,84 ± 1,85 mm, r = 0,8, p < 0,0001; 2D-TEE vs. 3D-TEE 0,27 ± 1,14 mm, r = 0,91, p < 0,02; 2D-TTE vs. 3D-TEE 0,58 ± 2,21 mm, r = 0,72, p = 0,02); however, differences between measurements amounted up to 6,1 mm. Interobserver variability for 2D-TTE and 2D-TEE was substantially higher compared with RT3D-TEE. We found significant differences in the dimensions of the aortic annulus measured by 2D-TTE, 2D-TEE and RT3D-TEE. Thus, in patients referred for TAVI, the echocardiographic method used may have an impact on TAVI strategy.

Guidance of percutaneous transcatheter aortic valve implantation by real-time three-dimensional transesophageal echocardiography – A single-center experience

Percutaneous transcatheter aortic valve implantation (TAVI) is an evolving interventional therapy for high-risk, non-surgical patients with severe, symptomatic aortic valve stenosis (AS). As a standard procedure, 2D transesophageal echocardiography has been used for the preinterventional assessment of the native valve and measurement of the aortic annulus as well as for intraprocedural guidance. Recently, a new matrix array, transesophageal probe for real-time three-dimensional echocardiography (RT3D-TEE) has been introduced. We applied this new technique to monitor percutaneous aortic valve implantation and described our initial experiences with this method in patients undergoing TAVI. We hypothesized that RT3D-TEE provides improved evaluation of the native aortic valve and annulus dimension due to unlimited scan plane orientation. This new technology should also enable accurate guiding of percutaneous cardiac interventions by providing immediate information on prosthesis position and function in real-time. In our preliminiary clinical experience real-time three-dimensional transesophageal echocardiography (RT3D TEE) was demonstrated to provide improved guiding of percutaneous aortic valve replacement by superior spatial visualisation of the cardiac structures and facilitated the detection of procedure-related complications. Due to the advantages of real-time 3D TEE monitoring, this technique might improve the outcome of patients treated with percutaneous aortic valve replacement.

Direct Quantification of Mitral Regurgitant Flow Volume by Real-Time Three-Dimensional Echocardiography Using Dealiasing of Color Doppler Flow at the Vena Contracta

BACKGROUND Real-time 3-dimensional color Doppler echocardiographic (RT3DE) imaging has recently been demonstrated to provide accurate direct measurement of vena contracta area (VCA). The quantification of mitral regurgitant (MR) flow directly at the lesion using color Doppler echocardiography, however, has been prevented because of multiple aliasing from high flow velocities. Recent studies, however, have demonstrated that flow at the vena contracta is laminar, with a narrow velocity spectrum that should allow the dealiasing of color Doppler flow velocities for the accurate measurement of MR flow. This hypothesis was tested in an in vitro flow model and initial patient application, with magnetic resonance imaging (MRI) used as a reference. METHODS In an in vitro flow model, MR jets of flow rates from 5 to 60 mL/s were produced through asymmetric orifices of 0.2 to 0.6 cm(2). From RT3DE data sets, MR flow was calculated by the automated integration of the nonaliased color Doppler velocities over the VCA, with aliasing avoided by maximum baseline shift. Aliased flow was calculated as VCA times the Nyquist velocity times the number of aliasing transitions derived from the maximum continuous-wave Doppler velocity. Total MR flow was calculated as the sum of nonaliased and aliased flow. This approach was also clinically evaluated in 23 patients for the measurement of MR stroke volume against MRI and the hemispheric and hemielliptic proximal isovelocity surface area methods. RESULTS In vitro RT3DE imaging of VCA was feasible in all flow stages without color Doppler aliasing. Flow rates calculated from RT3DE data sets showed excellent correlation with actual flow rates (r = 0.99), with a mean difference of -0.05 +/- 0.5 mL/s (not significant by t test). In vivo, good correlation and agreement were found between MR stroke volume by dealiasing and MRI (r = 0.91, -1.8 +/- 7.1 mL; not significant by t test), with better correlation and agreement compared with hemispheric proximal isovelocity surface area (r = 0.81, -17.4 +/- 9.4 mL, P < .05) and hemielliptic proximal isovelocity surface area (r = 0.89, -11.7 +/- 7.4 mL, P < .05). CONCLUSIONS Dealiasing of color Doppler flow at the vena contracta is feasible and appears promising for measuring MR severity quantitatively. This novel approach can be readily implemented in current systems to provide rapid semiautomated MR flow volume and MR fraction.

Incidence, outcome and correlates of residual paravalvular aortic regurgitation after transcatheter aortic valve implantation and importance of haemodynamic assessment.

AIMS Residual paravalvular aortic regurgitation (PAR) after transcatheter aortic valve implantation (TAVI) is common. We therefore evaluated incidence, determinants and outcome of PAR after TAVI. METHODS AND RESULTS Data from 167 consecutive transcatheter TAVI patients were analysed. PAR was graded by angiography and the pressure gradient between diastolic aortic pressure and left ventricular end-diastolic pressure (∆PDAP-LVEDP) after implantation. TAVI was technically successful in all patients. Mortality was 9% and 20% at 30 days and one year, respectively. Post-procedural PAR was absent in 54 patients (32.3%). Mild PAR was found in 89 (53.3%), moderate in 21 (12.6%), and moderate-to-severe in three patients (1.8%). Cardiovascular mortality at 30 days and one year was increased in patients with moderate and moderate-to-severe PAR compared to patients with no and mild PAR (46% vs. 4% and 73% vs. 7%, respectively, p<0.001). Receiver operating characteristic curve analysis suggested ∆PDAP-LVEDP ≤18 mmHg as a novel predictor of mortality, with an area under the curve of 0.97. CONCLUSIONS In patients undergoing TAVI, moderate and moderate-to-severe PAR was observed in 14.4% and associated with increased cardiovascular mortality. A pressure gradient ∆PDAP-LVEDP≤18 mmHg carries adverse prognosis and requires further intervention.

Risk and outcomes of complications during and after MitraClip implantation: Experience in 828 patients from the German TRAnscatheter mitral valve interventions (TRAMI) registry

To analyze risk and outcomes of complications during and after MitraClip implantation using multicenter data from the prospective German Transcatheter Mitral Valve Interventions (TRAMI) registry.