Robert M.A. van der Boon

Timing, Predictive Factors, and Prognostic Value of Cerebrovascular Events in a Large Cohort of Patients Undergoing Transcatheter Aortic Valve Implantation

Background— The objective of this study was to evaluate the timing, predictive factors, and prognostic value of cerebrovascular events (CVEs) after transcatheter aortic valve implantation. Methods and Results— The study included 1061 consecutive patients who underwent transcatheter aortic valve implantation with a balloon-expandable (64%) or self-expandable (36%) valve. CVEs were classified as acute (⩽24 hours), subacute (1–30 days), or late (>30 days). CVEs occurred in 54 patients (5.1%; stroke, 4.2%) within 30 days after transcatheter aortic valve implantation (acute in 54% of cases). The predictors of acute CVEs were balloon postdilation of the valve prosthesis (odds ratio, 2.46; 95% confidence interval,1.07–5.67) and valve dislodgment/embolization (odds ratio, 4.36; 95% CI, 1.21–15.69); new-onset atrial fibrillation (odds ratio, 2.76; 95% CI, 1.11–6.83) was a predictor of subacute CVEs. Late CVEs occurred in 35 patients (3.3%; stroke, 2.1%) at a median follow-up of 12 months (3–23 months). The predictors of late CVEs were chronic atrial fibrillation (2.84; 95% CI, 1.46–5.53), peripheral vascular disease (hazard ratio, 2.02; 95% CI, 1.02–3.97), and prior cerebrovascular disease (hazard ratio, 2.04; 95% CI, 1.01–4.15). Major stroke was associated with 30-day (odds ratio, 7.43; 95% CI, 2.45–22.53) and late (hazard ratio, 1.75; 95% CI, 1.01–3.04) mortality. Conclusions— In a large cohort of patients undergoing transcatheter aortic valve implantation, the rates of acute and subacute CVEs were 2.7% and 2.4%, respectively. While balloon postdilation and valve dislodgment/embolization were the predictors of acute CVEs, new-onset atrial fibrillation determined a higher risk for subacute events. Late events were determined mainly by a history of chronic atrial fibrillation and peripheral and cerebrovascular disease. The occurrence of major stroke was associated with increased early and late mortality. These results provide important insights for the implementation of preventive measures for CVEs after transcatheter aortic valve implantation.

Left Bundle-Branch Block Induced by Transcatheter Aortic Valve Implantation Increases Risk of Death

Background— Transcatheter aortic valve implantation (TAVI) is a novel therapy for treatment of severe aortic stenosis. Although 30% to 50% of patients develop new left bundle-branch block (LBBB), its effect on clinical outcome is unclear. Methods and Results— Data were collected in a multicenter registry encompassing TAVI patients from 2005 until 2010. The all-cause mortality rate at follow-up was compared between patients who did and did not develop new LBBB. Of 679 patients analyzed, 387 (57.0%) underwent TAVI with the Medtronic CoreValve System and 292 (43.0%) with the Edwards SAPIEN valve. A total of 233 patients (34.3%) developed new LBBB. Median follow-up was 449.5 (interquartile range, 174–834) days in patients with and 450 (interquartile range, 253–725) days in patients without LBBB (P=0.90). All-cause mortality was 37.8% (n=88) in patients with LBBB and 24.0% (n=107) in patients without LBBB (P=0.002). By multivariate regression analysis, independent predictors of all-cause mortality were TAVI-induced LBBB (hazard ratio [HR], 1.54; confidence interval [CI], 1.12–2.10), chronic obstructive lung disease (HR, 1.56; CI, 1.15–2.10), female sex (HR, 1.39; CI, 1.04–1.85), left ventricular ejection fraction ⩽50% (HR, 1.38; CI, 1.02–1.86), and baseline creatinine (HR, 1.32; CI, 1.19–1.43). LBBB was more frequent after implantation of the Medtronic CoreValve System than after Edwards SAPIEN implantation (51.1% and 12.0%, respectively; P<0.001), but device type did not influence the mortality risk of TAVI-induced LBBB. Conclusions— All-cause mortality after TAVI is higher in patients who develop LBBB than in patients who do not. TAVI-induced LBBB is an independent predictor of mortality.

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.

Transcatheter Aortic Valve Implantation With the Edwards SAPIEN Versus the Medtronic CoreValve Revalving System Devices A Multicenter Collaborative Study: The PRAGMATIC Plus Initiative (Pooled-RotterdAm-Milano-Toulouse In Collaboration)

OBJECTIVES The aim of this study was to compare outcomes after transfemoral transcatheter aortic valve implantation with the Medtronic CoreValve (MCV) versus the Edwards SAPIEN/SAPIEN XT transcatheter heart valve (ESV) for severe aortic stenosis. BACKGROUND No large matched comparison study has been conducted so far evaluating both commercially available devices. METHODS The data from databases of 4 experienced European centers were pooled and analyzed. Due to differences in baseline clinical characteristics, propensity score matching was performed. Study objectives were Valve Academic Research Consortium outcomes at 30 days and 1 year. RESULTS In total, 793 patients were included: 453 (57.1%) treated with the MCV and 340 (42.9%) with the ESV. After propensity matching, 204 patients were identified in each group. At 30 days, there were no differences in all-cause mortality (MCV, 8.8% vs. ESV, 6.4%; hazard ratio [HR]: 1.422; 95% confidence interval [CI]: 0.677 to 2.984; p = 0.352), cardiovascular mortality (MCV, 6.9% vs. ESV, 6.4%; HR: 1.083; 95% CI: 0.496 to 2.364; p = 0.842), myocardial infarction (MCV, 0.5% vs. ESV, 1.5%; HR: 0.330; 95% CI: 0.034 to 3.200; p = 0.339), stroke (MCV, 2.9% vs. ESV, 1.0%; HR: 3.061; 95% CI: 0.610 to 15.346; p = 0.174), or device success (MCV, 95.6% vs. ESV, 96.6%; HR: 0.770; 95% CI: 0.281 to 2.108; p = 0.611). Additionally, there were no differences in major vascular complications (MCV, 9.3% vs. ESV, 12.3%; HR: 0.735; 95% CI: 0.391 to 1.382; p = 0.340) or life-threatening bleeding (MCV, 13.7% vs. ESV, 8.8%; HR: 1.644; 95% CI: 0.878 to 3.077; p = 0.120). MCV was associated with more permanent pacemakers (22.5% vs. 5.9%; HR: 4.634; 95% CI: 2.373 to 9.050; p < 0.001). At 1 year, there were no differences in all-cause (MCV, 16.2% vs. ESV, 12.3%; HR: 1.374; 95% CI: 0.785 to 2.407; p = 0.266) or cardiovascular (MCV, 8.3% vs. ESV, 7.4%; HR: 1.145; 95% CI: 0.556 to 12.361; p = 0.713) mortality. CONCLUSIONS No differences between the 2 commercially available transfemoral transcatheter aortic valve implantation devices were observed at the adjusted analysis in Valve Academic Research Consortium outcomes except for the need for permanent pacemakers with the MCV.

Incidence, Predictors, and Implications of Access Site Complications With Transfemoral Transcatheter Aortic Valve Implantation

Our study objective was to assess the incidence, predictors, and implications of access site complications related to transfemoral transcatheter aortic valve implantation (TAVI). We pooled the prospective TAVI databases of 5 experienced centers in Europe enrolling only transfemoral cases for this analysis. Access site complications were defined according to the Valve Academic Research Consortium end-point definitions. The global transfemoral TAVI database contained 986 patients. Percutaneous access and closure was performed in 803 patients (81%) and a surgical strategy in 183 (19%). Incidences of major vascular complications, life-threatening/disabling bleeding, and major bleeding were 14.2%, 11%, and 17.8% respectively. In the patient cohort with a completely percutaneous access strategy, major vascular complications and life-threatening/disabling bleedings were related to closure device failure in 64% and 29%, respectively. Female gender (odds ratio 1.63, 95% confidence interval 1.12 to 2.36) and use of >19Fr system (2.87, 1.68 to 4.91) were independent predictors for major vascular complications. Female gender (odds ratio 2.04, 95% confidence interval 1.31 to 3.17), use of >19Fr system (1.86, 1.02 to 3.38), peripheral arterial disease (2.14, 1.27 to 3.61), learning effect (0.45, 0.27 to 0.73), and percutaneous access strategy (2.39, 1.16 to 4.89) were independently associated with life-threatening/disabling bleedings. In conclusion, transfemoral TAVI is associated with a >10% incidence of major vascular-related complications. A considerable number of these events is related to arteriotomy closure failure. Arterial sheath size and female gender are important determinants of major vascular complications and life-threatening/disabling bleeding.

Histopathology of Embolic Debris Captured During Transcatheter Aortic Valve Replacement

Background— Recent transcatheter aortic valve replacement studies have raised concerns about adverse cerebrovascular events. The etiopathology of the embolized material is currently unknown. Methods and Results— A total of 40 patients underwent transcatheter aortic valve replacement with the use of a dual filter–based embolic protection device (Montage Dual Filter System, Claret Medical, Inc). Macroscopic material liberated during the transcatheter aortic valve replacement procedure was captured in the device filter baskets in 30 (75%) patients and sent for histopathologic analysis. The captured material varied in size from 0.15 to 4.0 mm. Amorphous calcified material (size, 0.55–1.8 mm) was identified in 5 patients (17%). In 8 patients (27%), the captured material (size, 0.25–4.0 mm) contained valve tissue composed of loose connective tissue (collagen and elastic fibers) with focal areas of myxoid stroma, with or without coverage by endothelial cells and intermixed with fibrin. In another 13 (43%) patients, collagenous tissue, which may represent elements of vessel wall and valvelike structures, was identified. In 9 patients (30%), thrombotic material was intermixed with neutrophils (size, 0.15–2.0 mm). Overall, thrombotic material was found in 52% of patients, and tissue fragments compatible with aortic valve leaflet or aortic wall origin were found in 52% (21/40) of patients. Conclusions— Embolic debris traveling to the brain was captured in 75% of transcatheter aortic valve replacement procedures where a filter-based embolic protection device was used. The debris consisted of fibrin, or amorphous calcium and connective tissue derived most likely from either the native aortic valve leaflets or aortic wall.

Frequency and Causes of Stroke During or After Transcatheter Aortic Valve Implantation

Transcatheter aortic valve implantation (TAVI) is invariably associated with the risk of clinically manifest transient or irreversible neurologic impairment. We sought to investigate the incidence and causes of clinically manifest stroke during TAVI. A total of 214 consecutive patients underwent TAVI with the Medtronic-CoreValve System from November 2005 to September 2011 at our institution. Stroke was defined according to the Valve Academic Research Consortium recommendations. Its cause was established by analyzing the point of onset of symptoms, correlating the symptoms with the computed tomography-detected defects in the brain, and analyzing the presence of potential coexisting causes of stroke, in addition to a multivariate analysis to determine the independent predictors. Stroke occurred in 19 patients (9%) and was major in 10 (5%), minor in 3 (1%), and transient (transient ischemic attack) in 6 (3%). The onset of symptoms was early (≤24 hours) in 8 patients (42%) and delayed (>24 hours) in 11 (58%). Brain computed tomography showed a cortical infarct in 8 patients (42%), a lacunar infarct in 5 (26%), hemorrhage in 1 (5%), and no abnormalities in 5 (26%). Independent determinants of stroke were new-onset atrial fibrillation after TAVI (odds ratio 4.4, 95% confidence interval 1.2 to 15.6), and baseline aortic regurgitation grade III or greater (odds ratio 3.2, 95% confidence interval 1.1 to 9.3). In conclusion, the incidence of stroke was 9%, of which >1/2 occurred >24 hours after the procedure. New-onset atrial fibrillation was associated with a 4.4-fold increased risk of stroke. In conclusion, these findings indicate that improvements in postoperative care after TAVI are equally, if not more, important for the reduction of periprocedural stroke than preventive measures during the procedure.

New conduction abnormalities after TAVI—frequency and causes

Transcatheter aortic valve implantation (TAVI) is increasingly used to treat patients with aortic stenosis who are considered to be too high-risk for surgical replacement of the aortic valve. Although the procedural risks are decreasing, the occurrence of new conduction abnormalities remains a vexing issue. Both left bundle branch block and atrioventricular dissociation can affect prognosis after TAVI. Understanding the intimate relationship between the atrioventricular conduction axis and the aortic root, in addition to elucidation of factors related specifically to the procedure, devices, and patients, might help to reduce these conduction abnormalities. The purpose of this Review is to assess, and offer insights into, the available information on the frequency of new conduction abnormalities associated with TAVI, their anatomical and procedural causes, and their clinical consequences.

Pacemaker dependency after transcatheter aortic valve implantation with the self-expanding Medtronic CoreValve System

BACKGROUND/OBJECTIVES To determine pacemaker (PM) dependency at follow-up visit in patients who underwent new permanent pacemaker implantation (PPI) following transcatheter aortic valve implantation (TAVI). METHODS Single center prospective observational study including 167 patients without previous PM implantation who underwent TAVI with the self-expanding Medtronic CoreValve System (MCS) between November 2005 and February 2011. PM dependency was defined by the presence of a high degree atrioventricular block (HDAVB; second [AV2] and third degree [AV3B]), or a slow (<30 bpm) or absent ventricular escape rhythm during follow-up PM interrogation. RESULTS A total of 36 patients (21.6%) received a new PM following TAVI. The indication for PM was AV2B (n=2, 5.6%), AV3B (n=28, 77.8%), postoperative symptomatic bradycardia (n=3, 8.3%), brady-tachy syndrome (n=1, 2.8%), atrial fibrilation with slow response (n=1, 2.8%) and left bundle branch block (n=1, 2.8%). Long term follow-up was complete for all patients and ranged from 1 to 40 months (median (IQR): 11.5 (5.0-18.0 months). Of those patients with a HDAVB, 16 out of the 30 patients (53.3%) were PM independent at follow-up visit (complete or partial resolution of the AV conduction abnormality). Overall, 20 out of the 36 patients (55.6%) who received a new PM following TAVI were PM independent at follow-up. CONCLUSION Partial and even complete resolution of peri-operative AV conduction abnormalities after MCS valve implantation occurred in more than half of the patients.

Aortic annulus dimensions and leaflet calcification from contrast MSCT predict the need for balloon post-dilatation after TAVI with the Medtronic CoreValve prosthesis

AIMS We compared the measurement of aortic leaflet calcification on contrast and non-contrast MSCT and investigated predictors of the need for balloon post-dilatation after TAVI. METHODS AND RESULTS In 110 patients, who had TAVI with a Medtronic CoreValve prosthesis (MCS) for symptomatic aortic stenosis, calcification of the aortic root was measured on non-contrast MSCT (conventionally) and on contrast MSCT (signal attenuation >450 Houndsfield units). Calcium volume was underestimated on contrast- when compared to non-contrast MSCT: median (IQ-range)=759 (466 to 1295) vs. 2016 (1376 to 3262) and the difference between the two methods increased with higher calcium volumes (correlation coefficient r=0.90). Calcium mass was only slightly underestimated on contrast vs. non-contrast MSCT: median (IQ-range)=441 (268 to 809) vs. 555 (341 to 950) and there was no association between the differences and increasing calcium mass (r=0.17). Balloon post-dilatation was performed for significant aortic regurgitation after TAVI in 11 of 110 patients. When compared to controls, the patients who required balloon post-dilatation had higher aortic leaflet calcium on contrast CT (p<0.01), higher aortic annulus diameters (p<0.01) and higher annulus to prosthesis area ratio (p=0.01). ROC curves demonstrated that aortic root or aortic leaflet calcium measured on either contrast- or non-contrast MSCT showed excellent discrimination for the requirement of balloon post-dilatation (area under ROC >0.80 for all), whereas the discriminatory value of aortic annulus dimensions was moderate (area under ROC=0.69) and that of prosthesis to annulus ratio was poor (area under ROC=0.36). CONCLUSIONS Dense aortic leaflet calcification measured on contrast MSCT discerned well the need for balloon post-dilatation after TAVI with an MCS for significant PAR. Non-contrast MSCT may no longer be needed to quantify aortic root calcium before TAVI.