Nicolo Piazza

Early and Persistent Intraventricular Conduction Abnormalities and Requirements for Pacemaking After Percutaneous Replacement of the Aortic Valve

OBJECTIVES In this retrospective study, we examined the incidence of post-procedural conduction abnormalities and the need for pacing in patients undergoing percutaneous implantation of the aortic valve. BACKGROUND Safety and feasibility studies have suggested anecdotally the occurrence of conduction abnormalities and requirements for pacing after percutaneous implantation of the aortic valve. METHODS We examined the standard 12-lead electrocardiograms (ECGs) of 40 consecutive patients in whom a CoreValve Revalving System (CoreValve, Paris, France) was implanted between November 2005 and March 2008. We examined the 12-lead ECG before treatment, after treatment, and at 1-month follow-up. We documented the requirements for temporary or permanent pacemaking. RESULTS The mean age of patients was 82 +/- 7 years. Post-procedural mortality at 72 h was 0%. There was a significant increase in the frequency of left bundle branch block (LBBB) after percutaneous aortic valve replacement (15% before treatment vs. 55% after treatment, p = 0.001). Although the incidence of LBBB had decreased after follow-up of 1 month, it did not reach statistical significance, with the proportion decreasing from 55% to 48% (p = 0.63). The only 2 patients with pre-treatment right bundle branch block became dependent on temporary pacing immediately after valve implantation and subsequently needed permanent pacing. A temporary and permanent pacemaker was required in 20% and 18% of patients, respectively. CONCLUSIONS In this study, there was a significant increase in the frequency of LBBB after percutaneous insertion of the aortic valvar prosthesis. Patients with pre-existing right bundle branch block may be at risk for the development of complete heart block and subsequent need for pacing.

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

AIMS To evaluate the effects of applying current sizing guidelines to different multislice computer tomography (MSCT) aortic annulus measurements on Corevalve (CRS) size selection. METHODS AND RESULTS Multislice 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). CONCLUSION Eligibility 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.

Geometry and Degree of Apposition of the CoreValve ReValving System With Multislice Computed Tomography After Implantation in Patients With Aortic Stenosis

OBJECTIVES Using multislice computed tomography (MSCT), we sought to evaluate the geometry and apposition of the CoreValve ReValving System (CRS, Medtronic, Luxembourgh, Luxembourgh) in patients with aortic stenosis. BACKGROUND There are no data on the durability of percutaneous aortic valve replacement. Geometric factors may affect durability. METHODS Thirty patients had MSCT at a median 1.5 months (interquartile range [IQR] 0 to 7 months) after percutaneous aortic valve replacement. Axial dimensions and apposition of the CRS were evaluated at 4 levels: 1) the ventricular end; 2) the nadir; 3) central coaptation of the CRS leaflets; and 4) commissures. Orthogonal smallest and largest diameters and cross-sectional surface area were measured at each level. RESULTS The CRS (26-mm: n = 14, 29-mm: n = 16) was implanted at 8.5 mm (IQR 5.2 to 11.0 mm) below the noncoronary sinus. None of the CRS frames reached nominal dimensions. The difference between measured and nominal cross-sectional surface area at the ventricular end was 1.6 cm(2) (IQR 0.9 to 2.6 cm(2)) and 0.5 cm(2) (IQR 0.2 to 0.7 cm(2)) at central coaptation. At the level of central coaptation the CRS was undersized relative to the native annulus by 24% (IQR 15% to 29%). The difference between the orthogonal smallest and largest diameters (degree of deformation) at the ventricular end was 4.4 mm (IQR 3.3 to 6.4 mm) and it decreased progressively toward the outflow. Incomplete apposition of the CRS frame was present in 62% of patients at the ventricular end and was ubiquitous at the central coaptation and higher. CONCLUSIONS Dual-source MSCT demonstrated incomplete and nonuniform expansion of the CRS frame, but the functionally important mid-segment was well expanded and almost symmetrical. Undersizing and incomplete apposition were seen in the majority of patients.

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

AIMS New-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). METHODS AND RESULTS Sixty-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. CONCLUSION Transcatheter 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.

Persistent conduction abnormalities and requirements for pacemaking six months after transcatheter aortic valve implantation

AIMS Early conduction abnormalities and need for pacemaking after transcatheter aortic valve implantation (TAVI) is well recognised. It is still unknown, however, if these conduction abnormalities are persistent, and what is the need for permanent pacemaking after 1-month follow-up. In this prospective study, we examined the incidence of post-procedural and 6-month conduction abnormalities and need for permanent pacemaking after TAVI. METHODS AND RESULTS We examined the 12-lead electrocardiogram (ECG) of 91 consecutive patients in whom a Medtronic CoreValve ReValving System was implanted between November 2005 and April 2009. We evaluated the ECGs before treatment, after treatment, at 1-month and 6-month follow-up. The requirement and timing of permanent pacemaking was documented. The mean age of patients was 81±7 years and the mean logistic EuroSCORE was 16±9%. Median duration of follow-up was 213 days (IQR 64, 519). There was a 39% increase in the frequency of LBBB after TAVI (15% before treatment vs. 54% after treatment, p<0.001). Importantly, there was no significant change in the frequency of LBBB from after treatment to 1- or 6-month follow-up (54% after treatment vs. 42% at 1-month follow-up, p=0.45, and 54% after treatment vs. 45% at 6-month follow-up, p=0.39). Permanent pacemaking was required in 17/91 (19%) of patients. A permanent pacemaker was implanted in 8/17 patients (47%) within seven days of TAVI, in 6/17 (35%) at 7-30 days, and in 3/17 (18%) after 30 days. Male gender, previous myocardial infarction, pre-existing right bundle branch block, actual diameter (mm) of the inflow portion of the CoreValve frame post-implantation and depth of implantation were predictors for new LBBB; pre-treatment QRS duration (msec) and septal wall thickness were predictors for permanent pacemaking. CONCLUSIONS These results suggest that early conduction abnormalities occurring after TAVI persist at 6-months follow-up. Patient-related, anatomical-related, and procedure-related factors need to be considered in the pathogenesis of conduction abnormalities after TAVI.

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.

Implantation of two self‐expanding aortic bioprosthetic valves during the same procedure—Insights into valve‐in‐valve implantation (“Russian doll concept”)

Transcatheter aortic value implantation has gained acceptance as a treatment for elderly patients considered high risk for surgical aortic valve replacement. There are still, however, many unresolved clinical and technical issues. The occurrence of transcatheter aortic valve‐in‐valve implantation has been reported anecdotally. Aside from a single case report, there is little literature on this topic. This study was conducted to evaluate the procedural, imaging, and clinical outcomes of patients who underwent transcatheter valve‐in‐valve implantation with two self‐expanding aortic valve bioprostheses during the same procedure. We discuss also the potential valve of on‐line quantitative angiography for assessing the depth of valve implantation and the need to implant a second valve.

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.