Outcome after transcatheter aortic valve implantation (TAVI) depends on the patient risk profile, operator experience, progress in technology, and technique. We sought to compare the results of TAVI during the initiation phase and after certification to perform TAVI with the Medtronic CoreValve System without proctoring. A total of 165 consecutive patients was categorized into a first cohort of 33 patients treated before certification (November 2005 to December 2007) and a second cohort of 132 patients treated after certification (January 2008 to October 2010). The study end points were selected and defined according to the Valve Academic Research Consortium recommendations. Compared to cohort 2, the patients in cohort 1 more frequently had New York Heart Association class III–IV (100% vs 71%, p <0.001), hypertension (67% vs 39%, p = 0.004), and aortic regurgitation grade III–IV (46% vs 22%, p = 0.006) before TAVI. Over time, the patients in cohort 2 more frequently underwent a truly percutaneous approach (98% vs 82%, p = 0.002) without circulatory support (96% vs 67%, p <0.001) but with more concomitant percutaneous coronary intervention (11% vs 0%, p = 0.042) than the patients in cohort 1. They also more often received a 29-mm prosthesis (72% vs 24%, p <0.001), required less postimplantation balloon dilation (10% vs 27%, p = 0.008), and had less aortic regurgitation grade III–IV after TAVI (12% vs 30%, p = 0.010). The clinical outcome showed a nonsignificant reduction in the combined safety end point (30% to 17%) but a significant reduction in cerebrovascular events (21% to 7%, p = 0.020) and life-threatening bleeding (15% to 5%, p = 0.044) in cohort 2. However, the reduction in overall bleeding and vascular complications (25% and 14%, respectively) was not significant. In conclusion, TAVI became significantly less complex and was associated with better results over time but remained associated with a high frequency of periprocedural major cardiovascular complications.
Compared to patients who underwent transcatheter aortic valve implantation (TAVI) in the early days, patients treated later have been reported to benefit from improved procedural success rates, with subsequent improved survival. The developments of smaller delivery catheters, improvements in frame technology, and increased operator experience, in addition to changes in the baseline risk of patients, have played a role. In the present study, we describe the effect of our experience, in addition to changes in patient demographics, procedure, and outcome of TAVI with the Medtronic CoreValve System (MCS), in a cohort treated before (2005 to 2007) and after (January 2008) certification to perform TAVI as a solo center.
Methods
From November 2005 to October 2010, 165 consecutive patients with severe aortic stenosis underwent TAVI with the MCS. All patients were accepted for TAVI by Heart Team consensus by a cardiologist and cardiac surgeon who agreed that surgical aortic valve replacement was associated with a too high or prohibitive risk, using previously reported criteria. The treatment decision was made on the basis of a comprehensive analysis of symptoms, physical examination findings, laboratory assessment, 12-lead electrocardiographic findings, 2-dimensional transthoracic echocardiography, including continuous pulsed wave Doppler examination of the aortic valve for calculation of the aortic valve area and mean gradient according to the recommendations of the American Society of Echocardiography, and assessment of the coronary and peripheral arteries by angiography or MSCT. During the study period, 322 patients were screened, for whom the acceptance rate for TAVI increased from 23% in 2006 to 76% in 2009. The patients agreed to TAVI in writing.
The details of the device and the procedure have been previously reported. The first 5 patients underwent TAVI with the second-generation MCS, which is implanted using a 21Fr delivery catheter inserted into the common femoral (n = 4) or the subclavian (n = 1) artery using surgical exposure without the use of an arterial sheath. All other patients underwent TAVI with the third-generation MCS, which is delivered using an 18Fr arterial sheath inserted into the femoral artery using an echocardiographic-guided Seldinger technique and closure with a 10Fr Prostar (Prostar XL, Abbott Vascular, Illinois); except for 4 who underwent the subclavian approach. All patients underwent general anesthesia, and valve implantation was done using cine and fluoroscopic guidance.
The preprocedural demographic, clinical, laboratory, and technical (electrocardiographic and echocardiographic) data were prospectively collected and entered in a dedicated database. Transthoracic echocardiography was performed 1 day before the procedure and within 7 days after TAVI. The details of the analysis have been previously reported. The Valve Academic Research Consortium recommendations were used for all separate and composite end points in the present study. The following separate clinical end points were collected during or immediately after TAVI: death, myocardial infarction, cerebrovascular complications, vascular and bleeding complications, and acute kidney injury (AKI). The following prosthetic valve associated end points were recorded: new left bundle branch block, new third-degree atrioventricular block, new permanent pacemaker implantation, and coronary obstruction. Finally, the therapy-specific end points were recorded, including ventricular perforation at any point resulting in cardiac tamponade, postimplantation balloon dilation, valve-in-valve implantation, and unplanned cardiopulmonary bypass with or without conversion to open surgical aortic valve replacement. All cerebrovascular events were evaluated and adjudicated by a vascular neurologist who reassessed such patients daily. The serum creatinine results ≤72 hours after the procedure were collected to identify the patients with AKI, and data on the red blood cell transfusions were recorded by our institution’s blood bank laboratory. Twelve-lead electrocardiographic recordings were obtained 1 day before treatment and 1 day after treatment, after which the electrocardiograms were examined by an independent cardiologist for the occurrence of new left bundle branch block.
To assess the effect of the experience on clinical outcome, the study population was divided into 2 patient cohorts. Cohort 1 (C-1) included the initial 33 patients treated from November 2005 to December 2007. Cohort 2 (C-2) included the subsequent 132 patients who were treated from January 2008 to October 2010. This distinction in time was made by receipt of certification in January 2008, attesting that our institution and team were qualified to perform TAVI without any additional assistance or the presence of a proctor. Also, 2005 to 2007 constituted the period during which TAVI evolved from a hybrid surgical approach with cardiopulmonary support to a truly percutaneous procedure (October 2006), with the gradual omission of circulatory support (December 2006).
The preprocedural, procedural, and in-hospital results were compared between the 2 groups. The categorical variables are presented as frequencies and percentages and were compared using the chi-square test or Fisher’s exact test. The normal and skewed continuous variables are presented as the mean ± SD and median (interquartile range), respectively. A comparison of the continuous variables was done using the Student t test or Wilcoxon rank sum test. Two-sided p values <0.05 were considered to indicate significance. All statistical analyses were performed using the Statistical Package for Social Sciences software, version 17.0 (SPSS, Chicago, Illinois).
Results
The baseline patient characteristics and procedural details of the entire population and the 2 cohorts are listed in Tables 1 and 2 , respectively. Compared to the C-2 patients, the C-1 patients were more symptomatic (New York Heart Association class III or IV, 100% vs 71%, p <0.001), more frequently had a history of hypertension (67% vs 39%, p = 0.004), and more often presented with aortic regurgitation grade III or greater (46% vs 22%, p = 0.006).
| Variable | Entire Cohort (n = 165) | Cohort 1 ⁎ (n = 33) | Cohort 2 ⁎ (n = 132) | p Value |
|---|---|---|---|---|
| Age (years) | 81 ± 8 | 82 ± 7 | 80 ± 8 | 0.39 |
| Men | 75 (46%) | 15 (46%) | 60 (46%) | 1.0 |
| Height (cm) | 167 ± 9 | 167 ± 8 | 167 ± 9 | 0.86 |
| Weight (kg) | 73 ± 13 | 73 ± 13 | 72 ± 13 | 0.77 |
| Body mass index (kg/m 2 ) | 26.0 ± 4.0 | 26.2 ± 4.6 | 26.0 ± 3.8 | 0.77 |
| Body surface area (m 2 ) | 1.83 ± 0.19 | 1.84 ± 0.19 | 1.83 ± 0.20 | 0.83 |
| New York Heart Association class ≥III | 127 (77%) | 33 (100%) | 94 (71%) | <0.001 |
| Previous cerebrovascular event | 35 (21%) | 8 (24%) | 27 (21%) | 0.63 |
| Previous myocardial infarction | 43 (26%) | 7 (21%) | 36 (27%) | 0.48 |
| Previous coronary artery bypass graft surgery | 42 (26%) | 10 (30%) | 32 (24%) | 0.48 |
| Previous percutaneous coronary intervention | 46 (28%) | 8 (24%) | 38 (29%) | 0.60 |
| Diabetes mellitus | 38 (23%) | 8 (24%) | 30 (23%) | 0.85 |
| Hypertension | 73 (44%) | 22 (67%) | 51 (39%) | 0.004 |
| Glomerular filtration rate <60 ml/min | 90 (55%) | 20 (61%) | 70 (53%) | 0.43 |
| Chronic hemodialysis | 8 (5%) | 2 (6%) | 6 (5%) | 1.0 |
| Chronic obstructive pulmonary disease | 45 (27%) | 7 (21%) | 38 (29%) | 0.89 |
| Permanent pacemaker | 26 (16%) | 5 (15%) | 21 (16%) | 0.89 |
| Atrial fibrillation | 40 (25%) | 7 (21%) | 33 (25%) | 0.62 |
| Aortic valve annulus (mm) | 22.6 ± 2.2 | 22.7 ± 2.3 | 22.6 ± 2.2 | 0.97 |
| Aortic valve area (cm 2 ) | 0.64 ± 0.21 | 0.67 ± 0.17 | 0.63 ± 0.22 | 0.34 |
| Mean aortic gradient | 45 ± 17 | 48 ± 19 | 45 ± 16 | 0.38 |
| Aortic regurgitation grade III or greater | 44 (27%) | 15 (46%) | 29 (22%) | 0.006 |
| Mitral regurgitation grade III or greater | 23 (14%) | 7 (21%) | 16 (21%) | 0.18 |
| Logistic European System for Cardiac Operative Risk Evaluation | 13.1 (9.8–19.4) | 14.2 (10.5–18.7) | 12.6 (9.6–21.2) | 0.53 |
| Society of Thoracic Surgeons’ score | 4.6 (3.3–6.7) | 5.3 (3.0–8.0) | 4.6 (3.3–6.3) | 0.28 |
⁎ Cohort 1 and 2 included patients treated before (n = 33) and after (n = 132) institutional qualification and certification in January 2008 to perform TAVI as a solo center without additional assistance of a proctor, respectively.
| Variable | Cohort 1 (n = 33) | Cohort 2 (n = 132) | p Value |
|---|---|---|---|
| Vascular access | |||
| Surgical—femoral artery | 4 (12%) | 0 | 0.001 |
| Surgical—subclavian artery | 2 (6%) | 3 (2%) | 0.59 |
| Percutaneous—femoral artery | 27 (82%) | 128 (98%) | 0.002 |
| Circulatory support ⁎ | |||
| Extracorporeal membrane oxygenation | 2 (6%) | 1 (1%) | 0.10 |
| Left ventricular assist device | 9 (27%) | 4 (3%) | <0.001 |
| None | 22 (67%) | 126 (96%) | <0.001 |
| Additional interventions during procedure | |||
| Percutaneous transluminal angioplasty iliac artery | 3 (9%) | 2 (2%) | 0.055 |
| Percutaneous coronary intervention | 0 | 15 (11%) | 0.042 |
| Prosthesis size † (mm) | |||
| 26 | 25 (76%) | 36 (28%) | <0.001 |
| 29 | 8 (24%) | 94 (72%) | <0.001 |
| Therapy-specific results | |||
| Ventricular perforation resulting in cardiac tamponade | 1 (3%) | 0 | 1.0 |
| Postimplantation balloon dilation | 9 (27%) | 13 (10%) | 0.008 |
| Valve-in-valve implantation | 3 (9%) | 5 (4%) | 0.36 |
| Unplanned cardiopulmonary bypass use | 0 | 0 | 1.0 |
| Conversion to open surgical aortic valve replacement | 0 | 0 | 1.0 |
| Contrast volume (ml) | 211 ± 71 | 176 ± 83 | 0.041 |
| Duration of procedure (min) | 230 ± 74 | 257 ± 80 | 0.099 |
⁎ One patient died during induction of anesthesia.
† Two patients did not receive a valve (1 death during induction of anesthesia and 1 death after balloon valvuloplasty).
The C-2 patients more frequently underwent a truly percutaneous transfemoral approach (98% vs 82%, p = 0.002) without circulatory support (96% vs 67%, p <0.001) but more often underwent concomitant percutaneous coronary intervention during the TAVI procedure (11% vs 0%, p = 0.042). Because the 29-mm inflow valve became available in October 2007, a smaller proportion of C-1 patients received a 29-mm inflow valve (24% vs 72%, p <0.001). Thus, additional balloon dilation immediately after valve implantation was used less often in the C-2 patients (10% vs 27%, p = 0.008). The TAVI procedures in C-2 were also characterized by a reduced use of contrast media (176 vs 211 ml, p = 0.041).
A trend was seen toward an increase in all-cause mortality over time (3% to 11%). The time and cause of death in the 15 patients in C-2 were as follows; 3 intraprocedural (induction of anesthesia, left ventricular outflow tract rupture, and electromechanical dissociation in 1 each), 11 in-hospital (major stroke in 3, heart failure in 2, sepsis in 2, pneumonia in 2, asystole in 1, and pneumothorax during permanent pacemaker implantation in 1), and 1 sudden death immediately after discharge. Despite this, a trend was seen toward a reduction of the combined safety end point at 30 days from 30% to 17% ( Table 3 ). The latter was predominantly caused by a reduction in life-threatening bleeding events occurring during or immediately after TAVI (15% to 5%, p = 0.044). However, a significant reduction occurred in cerebrovascular complications (21% to 7%, p = 0.020), mainly because of a reduction in transient ischemic attacks (12% to 1%, p = 0.006). Computed tomography of the brain was performed in all patients who experienced a major or minor stroke and revealed that the cause of the insult was ischemic in origin (embolus) in 81% and due to hemodynamic changes during the procedure (watershed) in 19% of the patients.
| Variable | Cohort 1 (n = 33) | Cohort 2 (n = 132) | p Value |
|---|---|---|---|
| In-hospital clinical outcome | |||
| Thirty day or in-hospital death | |||
| All-cause | 1 (3%) | 15 (11%) | 0.20 |
| Cardiovascular cause | 1 (3%) | 10 (8%) | 0.47 |
| Periprocedural myocardial infarction (<72 hours) | 1 (3%) | 0 | 0.20 |
| Spontaneous myocardial infarction (>72 hours) | 0 | 0 | 1.0 |
| Cerebrovascular complication | 7 (21%) | 9 (7%) | 0.020 |
| Major stroke | 3 (9%) | 7 (5%) | 0.69 |
| Minor stroke | 0 | 1 (1%) | 1.0 |
| Transient ischemic attack | 4 (12%) | 1 (1%) | 0.006 |
| Vascular complication | 6 (18%) | 19 (14%) | 0.59 |
| Major | 3 (9%) | 7 (5%) | 0.69 |
| Minor | 3 (9%) | 12 (9%) | 1.0 |
| Bleeding complication <24 hours | 8 (24%) | 33 (25%) | 0.95 |
| Life-threatening or disabling | 5 (15%) | 6 (5%) | 0.044 |
| Major | 3 (9%) | 18 (14%) | 0.48 |
| Minor | 0 | 9 (7%) | 0.12 |
| Bleeding complication >24 hours | 2 (6%) | 6 (5%) | 1.0 |
| Life-threatening or disabling | 1 (3%) | 3 (2%) | 1.0 |
| Major | 0 | 3 (2%) | 0.61 |
| Minor | 1 (3%) | 0 | 0.20 |
| Acute kidney injury | 9 (27%) | 18 (14%) | 0.056 |
| Stage 1 | 6 (18%) | 15 (11%) | 0.38 |
| Stage 2 | 1 (3%) | 2 (2%) | 1.0 |
| Stage 3 | 2 (6%) | 1 (1%) | 0.10 |
| In-hospital reintervention | 0 | 2 (2%) | 1.0 |
| Combined safety end point at 30 days † | 10 (30%) | 22 (17%) | 0.076 |
| Prosthetic-valve associated outcome | |||
| Conduction disturbances | |||
| Left bundle branch block | 14 (42%) | 61 (46%) | 0.70 |
| Pacemaker for third-degree atrioventricular block | 4 (12%) | 18 (14%) | 0.58 |
| Pacemaker for other than third-degree atrioventricular block | 2 (6%) | 5 (4%) | 0.63 |
| Coronary obstruction | 1 (3%) | 0 | 0.20 |
| Echocardiography results | |||
| Aortic valve area (cm 2 ) | 1.69 ± 0.53 | 1.76 ± 0.55 | 0.60 |
| Mean aortic gradient | 11 ± 6 | 9 ± 3 | 0.013 |
| Aortic regurgitation grade III or greater | 10 (30%) | 16 (12%) | 0.010 |
| Mitral regurgitation grade III or greater | 6 (18%) | 14 (10%) | 0.24 |
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