Wk Kim

Early SAPIEN transcatheter heart valve dysfunction due to tissue ingrowth in an octogenarian

A high-risk 83-year-old woman (Euroscore: 29 %, STSscore: 7 %) presented with severe aortic stenosis New York Heart Association class III. The interdisciplinary heart team considered her to be high-risk due to severe peripheral occlusive disease, which required several previous interventions, chronic renal insufficiency, diabetes mellitus and frailty. The patient thus received an Edwards SAPIEN XT prosthesis by transapical implantation using the 24F Ascendra-II sheath, in July 2011. The procedure went uneventfully and the patient was discharged 10 days after surgery. On discharge the patient received aspirin, clopidogrel (3 months) and low molecular heparin until full mobilization as antithrombotic therapy. ECG revealed good left ventricular and aortic valve prosthesis function with a small paravalvular leakage at that time (Fig. 1). Six months later her ambulatory follow-up visit was unremarkable, as well with persistently good aortic valve function (Fig. 1). After 1 year, the patient was readmitted to our hospital due to recurrent cardiac decompensations. She had to undergo leg amputation due to ulcus cruris caused by severe peripheral occlusive disease which was treated several times interventionally as well as surgically, prior to readmission. Her post-operative course after that procedure had been uneventful without any signs of wound healing problems. Several wound swabs and pathological examinations of the amputated limb could exclude any bacterial infection. At admission to our hospital, the patient showed no typical signs of infection. Initial blood chemistry before aortic replacement revealed a slightly raised CRP, but normal WBC count (Table 1). Transesophageal echocardiography revealed severe transvalvular aortic valve regurgitation and presence of one immobile leaflet at this time. Even though there were no direct clinical signs of endocarditis according to DUKE criteria, neither vegetations nor any positive blood cultures, the patient was evaluated for conventional redo procedure to definitively exclude an infectious event. Intraoperatively, the aortic valve prosthesis was in a stable intra-annular position. There were neither any macroscopic vegetations nor any paravalvular leak or dehiscence. The noncoronary leaflet occurred to be retracted (Fig. 2). The SAPIEN XT prosthesis was explanted and sent for further histological examination (Fig. 3). The native calcified aortic valve leaflets were then resected and a 25 mm Medtronic Hancock prosthesis was successfully implanted. Tricuspid valve repair was performed in addition. In total, cross clamp time was 75 min and bypass time 110 min. The post-operative course was uneventful, the patient was extubated the same day and had a good further recovery, despite the need for some temporary renal support. Discharge echocardiography showed sufficient aortic valve prosthesis with a mean gradient of 6 mmHg and a sufficient tricuspid valve repair with a mean gradient of 3 mmHg. J. Blumenstein (&) A. Van Linden W. K. Kim W. Skwara M. Schoenburg M. Arsalan J. Kempfert T. Walther Department of Cardiac Surgery, Kerckhoff-Klinik Heartcenter, Benekestrasse 2-8, 61231 Bad Nauheim, Germany e-mail: j.blumenstein@kerckhoff-klinik.de

Transcatheter aortic valve implantation in Germany

Over the past years, there has been a tremendous evolution of transcatheter aortic valve implantation (TAVI) that turned a novel revolutionary approach to a mature concept. Peri-procedural complications and mortality rates have markedly decreased; hence, TAVI became an integral component of the treatment strategy for patients with severe aortic stenosis and now is the preferred therapy in elderly patients with moderate to high or prohibitive operative risk. This successful development would not have been possible without the joint efforts of clinicians, scientists, engineers, and many others from around the world. In this context, Germany has been one of the forerunners in implanting transcatheter heart valves, as evidenced not only by the high numbers of procedures, but in particular by some individual pioneering achievements. Here, we picture German contributions in the field of TAVI that had impact on clinical practice, including first-in-man experience, CE mark trials, randomized studies, large registries, and other procedurally relevant aspects.

Accuracy of device landing zone calcium volume measurement with contrast-enhanced multidetector computed tomography

BACKGROUND The extent of aortic valve calcification is an important determinant of procedural success in transcatheter aortic valve implantation (TAVI). We sought to validate device landing zone calcium volume (DLZ-CV) measurements on contrast-enhanced multidetector computed tomography (MDCT) with non-contrast-enhanced scans as reference. METHODS We determined DLZ-CV in 141 patients undergoing transfemoral TAVI. Non-contrast-enhanced images were analyzed using a threshold of 130 HU as reference (DLZ-CV130). For contrast-enhanced scans, we applied various thresholds including 450 HU (DLZ-CV450), 850 HU (DLZ-CV850), mean aortic attenuation (AttenAo) + 2 SD (DLZ-CV2SD), AttenAo + 4 SD (DLZ-CV4SD), AttenAo + 4 SD + 5 mm3 volume filter (DLZ-CV4SD+), and based on visual estimation (DLZ-CVvis). We compared DLZ-CV values between patients with versus without paravalvular leak (PVL), and between patients with versus without post-dilatation stratified by the type of prosthesis. RESULTS All DLZ-CV measurements on contrast-enhanced scans significantly differed from DLZ-CV130 (p < 0.001 for all comparisons). The best approximation to DLZ-CV130 was achieved with DLZ-CV4SD+ (508 mm3 [332-772]; Pearson correlation: R = 0.87, p < 0.001; Bland-Altman: mean difference 1339 mm3 [limits of agreement 79;2600]). Moreover, DLZ-CV4SD+ allowed for discrimination of PVL ≥1° or the need for post-dilatation in patients receiving self-expanding prostheses. Procedural outcome using balloon-expandable prostheses was independent of DLZ-CV. CONCLUSION Measurement of DLZ-CV using contrast-enhanced scans with unadjusted thresholds results in incorrect estimation of the calcium volume. The use of a scan-specific individual HU threshold including a volume filter (DLZ-CV4SD+) provides the best approximation to the reference and allows for discrimination of PVL ≥ 1° in patients receiving the Acurate neo prosthesis.

The Future of TAVI

Transcatheter aortic valve implantation (TAVI) has emerged as the established therapy for patients with severe, symptomatic native aortic stenosis at high operative risk. Many articles on this topic start with this or a similar introduction, which reflects the enormous progress that has been witnessed in recent years, hence reaching the current high standard. However, before dealing with the future of TAVI, it is valuable to examine its history, to understand the dynamic progress of this novel treatment option. The initial experience was dominated by multiple challenges, including significant paravalvular regurgitation (PVL), aortic root injury, malpositioning, device embolization, conduction disturbances, and access-related complications. Bail-out measures such as conversion to conventional surgery or implantation of a second valve were frequently required. Device-related issues included difficult implantation techniques, limited availability of sizes, and large stiff delivery systems (Figure 1). Further problems were related to patient selection, inappropriate sizing, and lack of operator experience. It is remarkable that TAVI became successful within a relatively short period of time, particularly when compared with other interventional therapies. Among numerous factors that contributed to improved outcomes, there are a few milestones of TAVI therapy that should be highlighted:

Outcome of thrombus aspiration in STEMI patients: a propensity score-adjusted study

The use of thrombus aspiration (TA) prior to primary percutaneous coronary intervention (PPCI) has undergone a radical change in intervention guidelines. The clinical implications, however, are still under scrutiny. This study investigated the clinical effects and outcome of TA before PPCI in patients with ST-segment elevation myocardial infarction (STEMI). Overall 1027 patients with STEMI were analyzed in this retrospective, propensity score-adjusted, multicenter study. The primary endpoints were in-hospital and long-term mortality. There were 418 patients in the TA group and 609 in the conventional PPCI group. The in-hospital mortality rate was significantly higher in the TA group (8.7 vs. 5.0%; P = 0.03). During long-term follow-up [median follow-up duration 689 days (IQR 405–959)] the mortality rates were similar (TA 14.3%, conventional PPCI 15.0%; P = 0.85). Survival analysis for the complete observation period revealed no significant benefit of TA [hazard ratio (HR) 1.12; 97.5% CI 0.90–0.71; P = 0.63]. There were also no significant differences between the groups in the following secondary endpoints: composite of cardiovascular death and non-fatal reinfarction at discharge (P = 0.39), post-PPCI thrombolysis in myocardial infarction flow-grade-3 (P = 0.14), left ventricular ejection fraction (P = 0.47), and non-fatal reinfarction during follow-up (P = 0.17). Rehospitalization rate (1.82 vs. 10.3%; P < 0.0001) and Canadian Cardiovascular Society (CCS) grading (P = 0.02) during follow-up were significantly lower in the TA group. In our cohort the in-hospital mortality rate was significantly higher for TA patients, but during long-term follow-up the mortality rates did not differ. The incidence of rehospitalization and CCS grading were lower in the TA-treated patients.

Early changes in N-terminal pro-B-type natriuretic peptide levels after transcatheter aortic valve replacement and its impact on long-term mortality

BACKGROUND N-terminal pro-hormone B-type natriuretic peptide (NT-proBNP) levels correlate with higher peri-procedural mortality after transcatheter aortic valve replacement (TAVR). The long-term prognostic value of NT-proBNP within the first days after TAVR, however, remains unclear. This study examined early changes in NT-proBNP prior to and within 6 days after TAVR, the diagnostic value of this biomarker regarding aortic regurgitation (AR), and its prognostic value regarding one-year mortality. METHODS AND RESULTS NT-proBNP concentrations were measured in 504 consecutive patients undergoing transapical (TA) or transfemoral (TF) TAVR before and directly after TAVR as well as 4 h and 1, 2, 3, and 6 days after TAVR. The follow-up period was 1 year. NT-proBNP was elevated in all patients at baseline (median 2141 ng/L [IQR 1021-5319 ng/L]). NT-proBNP changes in the first 6 days after TAVR showed significant differences depending on the approach, with a greater and more prolonged rise evident in TA-TAVR patients. NT-proBNP was an independent predictor of mortality in TA patients with AR, with an AUC of 0.794 (95% CI 0.663-0.925; P = 0.003) when measured on day 3 after TAVR. For TF patients with AR and reduced left ventricular systolic function, the AUC for prediction of mortality was 0.897 (95% CI 0.778-1.0; P = 0.004) on day 2. CONCLUSIONS The prognostic information of early post-procedural NT-proBNP concentrations is superior to pre-procedural values regarding all-cause mortality within 1 year. Post-procedural NT-proBNP must be interpreted in relation to the TAVR approach. NT-proBNP predicts mortality in TF-TAVR patients with AR and reduced left ventricular function.

Patient Outcomes of Self-expanding versus Balloon Expandable Transcatheter Valves in the Heavily Calcified Aortic Annulus

Objective: Aim of this study was to evaluate the performance of different transcatheter aortic valve prostheses in heavily calcified aortic annuli. Methods: Between, January 2011 and May 2015, 1119 patients received transcatheter aortic valve implantations (TAVI) at our institution. 278 of these patients (age 81.8 ± 6.2 years, logistic EuroSCORE 24.2 ± 12.6%) were identified at multi-slice CT (MSCT) screening, of having a heavily calcified aortic annulus. This was defined as a calcium score of greater than the 75% (>3600 AU) on MSCT. 128 patients were treated with self-expanding and 150 patients with balloon expandable TAVI prostheses. Clinical endpoints were procedural complications, device success (VARC II) and 30 day all-cause mortality. Results: 30 day mortality was comparable between the groups (self-expanding 6.3% versus balloon expandable 6.7%, p = 0.89). Residual aortic regurgitation > Grade II was higher in the self-expanding group (16.7% versus 4.7%, p = 0.0001). Procedural failure was also increased in the self-expanding group (25.8% versus 15.3%, p = 0.03). Other major complication rates like annular rupture (1.6% versus 1.3%, p = 0.87), stroke (2.3% versus 4%, p = 0.44), new onset pace maker implantation (12.5% versus 13.3%, p = 0.84) and conversion to conventional surgery (4.7% versus 3.3%, p = 0.56) were comparable between the groups. Conclusion: TAVI in high risk surgical patients, with severely calcified aortic annuli, is feasible with both self-expanding and balloon expandable prosthesis. However, procedural complications and residual aortic regurgitation are lower when using balloon expandable prostheses.

Variability of the aortic annulus measured in different planes with multislice computed tomography: Implications on clinical strategy

Introduction: Precise imaging of the aortic annulus is crucial for proper patient selection and safe performance of transcatheter aortic valve implantation (TAVI). However, accurate and reproducible 3-dimensional measurement is not trivial and prone to certain sources of error. Aim of our study was to determine the variation of annular dimensions acquired with multislice computed tomography (MSCT) in different planes parallel to the true annular plane and to verify whether there is any effect on clinical strategy. Methods: 146 patients with severe aortic stenosis who underwent TAVI between January 2012 to September 2012 and had pre-procedural MSCT were included in this retrospective study. Using a customized software (3 mensio Medical Imaging B.V., BS Bilthoven, The Netherlands) the effective annulus diameter was derived by planimetry of the annular area (pr2). By shifting the original annular plane in a stretched axial view towards aortic and left ventricular outflow tract (LVOT) direction taking 1 mm and 2 mm steps, in total 4 parallel images (towards aorta with 1 mm (AnnAo1) and 2 mm (AnnAo2) distance, towards LVOT with 1 mm (AnnLV1) and 2 mm (AnnLV2) distance from the original annular plane) were obtained. We examined the deviation of the annulus size in all different planes and analyzed the impact on the choice of valve prosthesis or TAVI strategy. Results: Mean age was 82 ± 5 years and logistic Euroscore 25.8 ± 13.6%. Effective annulus diameter was 22.6 ± 2.7 mm. The paired T-Test revealed a significant difference of annulus size when acquired in AnnAo1 (22.2 ± 2.1 mm; p < 0.001) and AnnAo2 (21.4 ± 2.4 mm; p < 0.001), while values in direction to the LVOT were almost identical (AnnLV1 22.8 ± 2.1 mm; AnnLV2 22.7 ± 2.1 mm; ns respectively). With respect to choice of valve prosthesis size, measurements in parallel planes AnnAo1, AnnAo2, AnnLV1 and AnnLV2 would have implied change of strategy in 26, 63, 15 and 17 patients with smaller valve size in 22 (15.1%), 63 (43.2%), 8 (5.5%) and 11 (7.5%) and larger valve size in 4 (2.7%), 0, 7 (4.8%) and 6 (4.1%) patients, respectively. Only measurements in AnnAo2 would have resulted in omittance of TAVI in 9 cases given too small annulus sizes. Conclusion: Variability of the aortic annulus in different axial planes increases towards aortic direction and shows no relevant difference when measured in orientation to LVOT.

Ventricular septum defect after TAVI: Rare but happens

Introduction: In the past years the numbers of transcatheter aortic valve implanation (TAVI) procedures performed have increased exponentially. With increasing numbers even rare complications of this relatively new technique were identified. Aim of this study was to analyze incidence of ventricular septum defect (VSD) after TAVI. Methods: A total of 510 high risk patients treated by TAVI through our interdisciplinary heart team were analyzed. Results: 4/510 (0.8%) patients (2 female, EuroSCORE: 20 ± 6%; STSscore: 5 ± 2%) suffering VSD after TAVI (Transfemoral = 3, Transapical = 1) procedure were identified. Three patients had received balloon expandable Edwards Sapien (1), Sapien XT (2) valves and one patient a self expandable valve (Symetis Accurate). In two patients postdilatation was performed due to severe aortic insufficiency during procedure leading to VSD. Postprocedural echocardiography and angiography revealed in a mild VSD in one patient with no further treatment and moderate/severe VSD in three patients. One patient received a second transcatheter valve, which was implanted transapically leading to VSD occlusion. Two patients received conventional aortic valve replacement due to severe aortic regurgitation with patch occlusion of the VSD. In all cases postinterventional echocardiography revealed a sufficient aortic valve prosthesis without VSD. One patient unfortunately died on POD six due to AV-Block III. All other patients survived. Conclusion: VSD after TAVI is a rare and unusual complication. It seems to be independent from different valve models but may be related to excessive calcifications. Further therapy consisting of a second TAVI procedure or surgical correction is warranted and leads to acceptable outcomes.