Apostolos Tzikas

Three dimensional evaluation of the aortic annulus using multislice computer tomography: are manufacturer's guidelines for sizing for percutaneous aortic valve replacement helpful?

AIMSnTo evaluate the effects of applying current sizing guidelines to different multislice computer tomography (MSCT) aortic annulus measurements on Corevalve (CRS) size selection.nnnMETHODS AND RESULTSnMultislice computer tomography annulus diameters [minimum: D(min); maximum: D(max); mean: D(mean) = (D(min) + D(max))/2; mean from circumference: D(circ); mean from surface area: D(CSA)] were measured in 75 patients referred for percutaneous valve replacement. Fifty patients subsequently received a CRS (26 mm: n = 22; 29 mm: n = 28). D(min) and D(max) differed substantially [mean difference (95% CI) = 6.5 mm (5.7-7.2), P < 0.001]. If D(min) were used for sizing 26% of 75 patients would be ineligible (annulus too small in 23%, too large in 3%), 48% would receive a 26 mm and 12% a 29 mm CRS. If D(max) were used, 39% would be ineligible (all annuli too large), 4% would receive a 26 mm, and 52% a 29 mm CRS. Using D(mean), D(circ), or D(CSA) most patients would receive a 29 mm CRS and 11, 16, and 9% would be ineligible. In 50 patients who received a CRS operator choice corresponded best with sizing based on D(CSA) and D(mean) (76%, 74%), but undersizing occurred in 20 and 22% of which half were ineligible (annulus too large).nnnCONCLUSIONnEligibility varied substantially depending on the sizing criterion. In clinical practice both under- and oversizing were common. Industry guidelines should recognize the oval shape of the aortic annulus.

Timing and potential mechanisms of new conduction abnormalities during the implantation of the Medtronic CoreValve System in patients with aortic stenosis.

AIMSnNew-onset left bundle branch block (LBBB) and complete atrioventricular block (AV3B) frequently occur following transcatheter aortic valve implantation (TAVI). We sought to determine the timing and potential mechanisms of new conduction abnormalities (CAs) during TAVI, using the Medtronic CoreValve System (MCS).nnnMETHODS AND RESULTSnSixty-five consecutive patients underwent TAVI with continuous 12-lead ECG analysis. New CAs were defined by the occurrence of LBBB, RBBB, and/or AV3B after the following pre-defined time points: (i) crossing of valve with stiff wire, (ii) positioning of balloon catheter in the aortic annulus, (iii) balloon valvuloplasty, (iv) positioning of MCS in the left ventricular outflow tract (LVOT), (v) expansion of MCS, (vi) removal of all catheters. A new CA occurred during TAVI in 48 patients (74%) and after TAVI in 5 (8%). Of the 48 patients with procedural CAs, a single new CA occurred in 43 patients (90%) and two types of CAs in 5 (10%). A new LBBB was seen in 40 patients (83%), AV3B in 9 (19%), and RBBB in 4 (8%). The new CA first occurred-in descending order of frequency-after balloon valvuloplasty in 22 patients (46%), MCS expansion in 14 (29%), MCS positioning in 6 (12%), positioning of balloon catheter in 3 (6%), wire-crossing of aortic valve in 2 (4%), and after catheter removal in 1 patient (2%). Patients who developed a new CA during balloon valvuloplasty had a significantly higher balloon/annulus ratio than those who did not (1.10±0.10 vs. 1.03±0.11, P=0.030). No such relationship was found with the valve/annulus ratio.nnnCONCLUSIONnTranscatheter aortic valve implantation with the MCS was associated with new CAs in 82% of which more than half occurred before the actual valve implantation. It remains to be elucidated by dedicated studies whether new CAs can be reduced by appropriate balloon sizing-a precept that also holds for valve size given the observed directional signal of the valve size/aortic annulus ratio.

Frequency, determinants, and prognostic effects of acute kidney injury and red blood cell transfusion in patients undergoing transcatheter aortic valve implantation

Objectives: To determine the frequency and independent predictors of acute kidney injury (AKI) in addition to the prognostic implications of both AKI and periprocedural red blood cell (RBC) transfusions on 30 day and cumulative late mortality in patients undergoing transcatheter aortic valve implantation (TAVI). Background: RBC transfusions have been reported to predict AKI following TAVI. Data on the prognostic implications of both factors, however, are lacking. Methods: 126 consecutive patients underwent TAVI with the Medtronic CoreValve Revalving System. AKI was defined according to the valve academic research consortium definitions as an absolute increase in serum creatinine ≥0.3 mg dL−1 (≥26.4 μmol L−1) or a percentage increase ≥50% within 72 hr following TAVI. Results: Five patients on chronic haemodialysis and three intraprocedural deaths were excluded, leading to a final study population of 118 patients. AKI occurred in 19% of the patients necessitating temporary haemodialysis in 2%. Independent predictors of AKI included: previous myocardial infarction (OR: 5.72; 95% CI: 1.64–19.94), periprocedural (<24 hr) RBC transfusions (OR: 1.29; 95% CI: 1.01–1.70), postprocedural (<72 hr) leucocyte count (OR: 1.18; 95% CI: 1.02–1.37), and logistic EuroSCORE (OR: 1.08; 95% CI: 1.01–1.14). In patients with AKI, 30‐day mortality was 23% and cumulative late mortality (median: 13 months) was 55%. AKI (OR: 5.47; 95% CI: 1.23–24.21) and postprocedural leucocyte count (OR: 1.20; 95% CI: 1.03–1.38) were independent predictors of 30‐day mortality while AKI (HR: 2.79; 95% CI: 1.36–5.71) was the only independent predictor of late mortality. Conclusions: AKI following TAVI occurred in 19% of the patients. RBC transfusion was found to be an independent predictor of AKI, which in turn predicted both 30‐day and cumulative late mortality.

Changes in mitral regurgitation after transcatheter aortic valve implantation

Objectives: To assess the acute and intermediate changes in mitral regurgitation (MR) severity after transcatheter aortic valve implantation (TAVI) with the CoreValve Revalving SystemTM (CRS). Background: Following surgical aortic valve replacement, improvement in MR is reported in 27–82% of the patients. The changes in MR severity following CRS implantation are unknown. Methods: Transthoracic echocardiography was performed in 79 consecutive patients before and after treatment, and at the first outpatient visit. Left ventricular dimensions and ejection fraction (LVEF), left atrial (LA) size, and aortic gradient were measured. MR was assessed by color flow mapping and was graded as none, mild, moderate, or severe. It was defined as organic or functional. The depth of CRS implantation was measured by angiography. Results: Post‐treatment, the mean gradient decreased from 48 ± 16 mm Hg to 9 ± 5 mm Hg (P < 0.0001). There was no significant change in the left ventricular dimensions, LA size, and LVEF. MR pretreatment was mild, moderate, or severe in 57%, 18%, and 1% of the patients, respectively. It was defined as organic in 27 patients (36%) and functional in 27 patients (36%). The degree of MR remained unchanged in 61% of the patients, improved in 17%, and worsened in 22%. MR improvement was associated with a lower baseline LVEF (P = 0.02). There was no association between the changes in MR severity and the depth of CRS implantation. Conclusions: Most patients who underwent TAVI had some degree of MR. Overall there was no change in the degree of MR post‐treatment. Patients in whom MR improved had a lower LVEF at baseline.

Assessment of the aortic annulus by multislice computed tomography, contrast aortography, and trans-thoracic echocardiography in patients referred for transcatheter aortic valve implantation.

Objective: We sought to determine the level of agreement and the reproducibility of trans‐thoracic echocardiography (TTE), contrast aortography (CA) and multislice computed tomography (MSCT) for the assessment of the aortic annulus, in patients referred for Transcatheter Aortic Valve Implantation (TAVI). Background: Correct measurement of the aortic annulus is important for TAVI. Methods: The dimensions of the aortic annulus were measured using TTE, CA and MSCT in 70 patients with severe aortic stenosis, referred for TAVI. Agreement between imaging techniques and interobserver variability was assessed using the Bland ‐ Altman method and a linear regression model. Results: The MSCT Coronal view provided the largest mean annulus diameter (26.3 mm) followed by CA (24.4 mm), MSCT Mean (23.7 mm), TTE (22.6 mm), and MSCT Sagittal (21.8 mm) view. Differences in the annulus measurements were significant: MSCT Coronal view versus CA (mean, 95% confidence interval, Pearsons correlation) 2.0 mm, −1.9 to 6.0 mm, r = 0.72, CA versus MSCT Mean 0.2 mm, −3.3 to 3.7 mm, r = 0.76, MSCT Mean versus TTE 1.3 mm, −2.9 to 5.5 mm, r = 0.61, TTE versus MSCT Sagittal view 0.9 mm, −3.6 to 5.4 mm, r = 0.59, CA versus TTE 1.5 mm, −3.0 to 5.9 mm, r = 0.57. Interobserver variability was: TTE (mean, 95% confidence interval, Pearsons correlation) 0.29 mm, −4.2 to 4.8 mm, r = 0.57, CA 0.14 mm, −3.5 to 3.8 mm, r = 0.77, MSCT Mean 0.20 mm, −1.4 to 1.8 mm, r = 0.95. Conclusions: We found significant differences in the dimensions of the aortic annulus measured by MSCT, CA, and TTE. Interobserver variability for TTE and CA was substantially higher compared with MSCT.

Anatomy of the Mitral Valvular Complex and Its Implications for Transcatheter Interventions for Mitral Regurgitation

Mitral regurgitation (MR) poses a significant clinical burden in the adult population, which is expected to increase even more with the ever prolonging life expectancies in developed countries. New technology has brought MR, once exclusively the arena of cardiac surgeons, to the attention of interventional cardiologists. A variety of device-oriented transcatheter strategies have evolved in recent years. A comprehensive understanding of mitral valvular anatomy is crucial for the selection of patients, the implementation of devices, and further refinements of these transcatheter techniques if they are eventually to produce procedural and clinical success. The aim of this review is to elucidate the morphology of the mitral valvular complex, integrating key anatomical features into the developing transcatheter options for the treatment of MR.

Correlates on MSCT of paravalvular aortic regurgitation after transcatheter aortic valve implantation using the medtronic corevalve prosthesis

Background: To investigate the causes of paravalvular aortic regurgitation (PAR) after the implantation of the Medtronic CoreValve prosthesis (MCRS). Methods and Results: Fifty‐six patients underwent MSCT before TAVI with a MCRS and PAR was assessed with transthoracic echocardiography (TTE) between 5 and 10 days after TAVI. The aortic annulus smallest and largest orthogonal diameters and the mean diameter from the area were determined on MSCT on an axial image at the nadir of all three native leaflets. PAR was related to relevant anatomical structures on MSCT according to a clockface in the orientation of the parasternal short axis view on TTE. PAR ≥ 1 was present in 25% of the patients and was associated with a larger annulus, a lower degree of over sizing and with more aortic root calcification. On MSCT post TAVI malapposition was seen predominantly at the aorto‐mitral fibrous continuity and the aspect of the largest diameter of the aortic annulus on the inside curve of the ascending aorta. PAR was predominantly seen at these two anatomic locations and less frequent in the area that contains the ventricular membranous septum and the area between the non‐ and right coronary sinus. Conclusions: Mild to moderate PAR is common after TAVI with the MCRS. The availability of additional (larger) prosthesis sizes in combination with improved sizing based on mean annulus diameter (e.g., DCSA) may help to reduce PAR.

In-hospital complications after transcatheter aortic valve implantation revisited according to the Valve Academic Research Consortium definitions.

Objectives: To determine the occurrence of in‐hospital complications after transcatheter aortic valve implantation (TAVI) according to the Valve Academic Research Consortium (VARC) criteria in addition to the length of stay (LOS). Background: The absence of uniformity in endpoint definitions challenges the comparison between previously reported major adverse cerebro‐ and cardiovascular event rates after TAVI. To address this, in 2009, the VARC was established aiming to provide standardized endpoint definitions for TAVI clinical trials. Methods: Between November 2005 and September 2010, we prospectively enrolled 150 consecutive patients who underwent TAVI with the Medtronic CoreValve System in our institution. Complications, prosthetic valve associated endpoints, and therapy‐specific endpoints were defined according to the definitions provided by the VARC. Results: The mean age (±SD) was 81 (±7) years and 55% were female. Thirty‐day or in‐hospital mortality was 11%, and the 30‐day combined safety endpoint was 22%. Seventy‐six patients (51%) had ≥1 cardiovascular and/or noncardiovascular complication of whom 16 also underwent a new permanent pacemaker implantation (PPI). In the 74 patients with uneventful TAVI, 12 patients (8%) underwent PPI. TAVI was truly uneventful in 62 patients (41%). Bleeding complications were observed most frequently (31%), followed by acute kidney injury (18%), vascular complications (16%), and stroke/TIA (11%). The median LOS in patients with a complicated and a truly uncomplicated TAVI was 14.0 (8.0–20.5) and 8.0 (7.0–10.8) days, respectively (P < 0.001). Conclusion: TAVI was associated with ≥1 cardiovascular and/or noncardiovascular event in 51% of the patients; new PPI was needed in another 8%, and TAVI was truly uncomplicated in 41%. Complications and need for new PPI significantly prolonged LOS.

Frequency of Conduction Abnormalities After Transcatheter Aortic Valve Implantation With the Medtronic-CoreValve and the Effect on Left Ventricular Ejection Fraction

New conduction abnormalities occur frequently after transcatheter aortic valve implantation (TAVI). The relation between new conduction disorders and left ventricular (LV) systolic function after TAVI is unknown. The purpose of the present prospective, single-center study was to investigate the effect of TAVI on LV systolic function in relation to TAVI-induced conduction abnormalities. A total of 27 patients had undergone electrocardiography and transthoracic echocardiography the day before and 6 days after TAVI with the Medtronic-CoreValve system. The LV ejection fraction (EF) was calculated using the biplane Simpson method. The systolic mitral annular velocities and longitudinal strain were measured using speckle tracking echocardiography. After TAVI, 18 patients (67%) had new conduction abnormalities; 4 (15%) had a new paced rhythm and 14 patients (52%) had new left bundle branch block. In the patients with new conduction abnormalities, the EF decreased from 47 ± 12% to 44 ± 10%. In contrast, in those without new conduction abnormalities, the EF increased from 49 ± 12% to 54% ± 12%. The change in EF was significantly different among those with and without new conduction abnormalities (p <0.05). In patients without new conduction abnormalities, an improvement was found in the systolic mitral annular velocities and longitudinal strain (p <0.05). In contrast, in patients with new conduction abnormalities, the changes were not significant. In conclusion, the induction of new conduction abnormalities after TAVI with the Medtronic-CoreValve was associated with a lack of improvement in LV systolic function.

Optimal projection estimation for transcatheter aortic valve implantation based on contrast-aortography: validation of a Prototype Software.

We investigate the accuracy of a new software system (C‐THV, Paieon) designed to calculate the optimal projection (OP) view for transcatheter aortic valve implantation (TAVI) based on two aortograms, and its agreement with the operators choice. An optimal fluoroscopic working view projection with all three aortic cusps depicted in one line, is crucial during TAVI. In our institution selection of the OP is based on multislice computed tomography (MSCT). Seventy‐three consecutive patients referred for TAVI were divided into two groups. For the first group (53 patients, retrospective cohort) we compared the OP views estimated by C‐THV with the ones estimated by MSCT. For the second group (20 patients, prospective cohort), we compared the OP views estimated by C‐THV with the operators choice during TAVI. For the retrospective cohort, the mean absolute difference (mean ± SD) between C‐THV and MSCT was 6.6 ± 4.9 degrees. In 77% of the cases the mean difference between C‐THV and MSCT was <10 degrees. For the prospective cohort, the mean absolute difference (mean ± SD) between C‐THV and the operators choice was 5.5 ± 3.4 degrees. A mean difference of <10 degrees was found in 90% of the cases. In this study we found that the C‐THV software estimated the OP view for TAVI with good accuracy. The level of agreement between C‐THV and either the MSCT or the operators choice was deemed satisfactory, with the vast majority of observed differences being <10 degrees.