Early- and mid-term outcomes after transcatheter aortic valve implantation. Data from a single-center registry

Introduction

Aortic stenosis (AS) is the most common valvular heart disease in elderly patients and is associated with worse clinical outcomes [1]. Surgical aortic valve replacement (AVR) was for decades the standard treatment for patients with symptomatic, severe AS [2]. Transcatheter aortic valve implantation (TAVI) is a less invasive treatment option for elderly, high-risk patients with symptomatic severe AS than AVR. More importantly, TAVI improves survival [3] and quality of life [4] as compared to medical treatment in inoperable patients. Transcatheter aortic valve implantation is also non-inferior to AVR regarding survival in selected patients [5]. A successful TAVI procedure requires complex selection of patients, including detailed imaging information of the aortic valve anatomy and the peripheral arteries, and also critical clinical assessment by an interdisciplinary heart team [6]. The TAVI program started in 2008 in our institution, resulting in a single-center, prospective registry evaluating the safety and efficacy of consecutive TAVI procedures.

Aim

Thus, we sought to evaluate early- and mid-term clinical outcomes after TAVI in a single-center setting.

Material and methods

The study protocol was approved by the institutional Ethical Board. A total of 101 consecutive high-risk elderly patients with severe symptomatic AS undergoing TAVI were enrolled. Patient screening and selection was performed by a multidisciplinary heart team supported by clinical and imaging resources. TAVI procedures were performed using Edwards Sapien, Edwards Sapien XT, Edwards Sapien 3 (Edwards Lifesciences, Irvine, USA) Medtronic Corevalve (Medtronic Inc., Minneapolis, USA) and JenaValve (JenaValve Technology, Munich, Germany). Access routes were transfemoral and transapical. Procedures were performed under general anesthesia or analgosedation [7]. Antiplatelet therapy consisted of acetylsalicylic acid life-long and clopidogrel for 1 month, if the prolonged therapy was not required due to previous percutaneous coronary intervention (PCI). Anticoagulation was continued only if indicated. Baseline characteristics as well as procedural and outcome data were collected. Endpoints of the study included all-cause mortality at discharge, 30 days, 6 months and 12 months. Cardiovascular mortality, cerebrovascular events, myocardial infarction, bleeding complications, vascular or access site-related complications and acute kidney injury were also assessed. All endpoints were assessed according to the recommendations of the Valve Academic Research Consortium (VARC) [8, 9].

Statistical analysis

Continuous variables are presented as the median (interquartile range (IQR)) or mean value with standard deviation, where applicable. Categorical variables are expressed as numbers (percentages). The mortality rates during follow-up are presented using the Kaplan-Meier curve. Changes in categories of NYHA (New York Heart Association) and CCS (Canadian Cardiovascular Society) grade between baseline and follow-up were tested using the 2 test.
All tests were two-tailed, and a p value < 0.05 was considered statistically significant. All statistical analysis was performed using SPSS 15.0 (SPSS, Inc., Chicago, IL, USA).

Results

A total of 101 patients underwent an elective TAVI procedure between November 2008 and November 2014 for degenerative AS (100%). All patients were scheduled by the heart team for TAVI. The median age was 81.0 (76.0–84.0) years, and 60.4% were female. All patients were symptomatic, 83.2% presenting with NYHA class III + IV. The median aortic valve area (AVA) was 0.7 (0.5–0.8) cm2 and the median value of maximal/mean transaortic gradient was 89.5 (59.0–119.0)/54.5 (34.0–74.0) mm Hg. All patients were considered high-risk according to logistic EuroSCORE I 16.5 (7.0–23.0)% and STS (Society of Thoracic Surgeons) score 15.4 (4.0–24.0)%. Baseline characteristics of the patients are presented in Table I. Procedural data and results are presented in Table II. The TAVI procedures were performed in the catheterization laboratory (71%), hybrid room (27.7%) and operating room (1.9%) using either general anesthesia (91%) or analgosedation (9%). The transfemoral approach was the most commonly used (Table II). All patients underwent balloon aortic valvuloplasty prior to valve deployment. All patients received only one prosthesis, so no valve-in-valve procedure was necessary. Conversion to open heart surgery was required in 2 (2.0%) cases. In-hospital course data are presented in Table III. A total of 30% of patients were discharged to a rehabilitation clinic, while 60.2% of patients were discharged home and 9.8% of patients were sent back to the referring hospital. Immediate (in-hospital) clinical outcomes are provided in Table IV.
Short-term clinical outcomes within the first 30 days after TAVI are presented in Table IV. Cumulative all-cause mortality was 10.9%. All deaths were due to cardiovascular causes. The overall rate of cerebrovascular accidents after 30 days was 5.0%. The TAVI was effective in symptomatic alleviation (Figure 1), showing a reduction of dyspnea from 83.2% of patients in NYHA class III + IV at baseline to 13.2% at 30-day follow-up (p < 0.001) and CCS class III + IV in 64.7% of patients at baseline to 2.9% at 30 days (p < 0.001).
Midterm (6- and 12-month) clinical outcomes are presented in Table IV. Cumulative all-cause mortality for 6 and 12 months was 15.8% and 17.8%, respectively. All deaths were due to cardiovascular causes. The TAVI was still effective in symptom alleviation (Figure 1), showing a reduction of dyspnea from 83.2% of patients in NYHA class III + IV at baseline to 5.6% at 6 months and 4.9% at the 12-month follow-up (p < 0.001, Figure 1 A). CCS class III + IV was present only in 1.9% of patients after 6 and 12 months (both p < 0.001, Figure 1 B). Figure 2 represents the all-cause mortality rate during 12-month follow-up. Echocardiographic data at 30 days, 6 months and 12 months are provided in Table V. Only 1 patient had a severe aortic regurgitation (AR) associated with paravalvular leak after Medtronic CoreValve implantation (Table IV). New pacemaker implantation was required in 16 (15.8%) patients after 12 months due to third or high grade second degree atrioventricular block. The in-hospital rate of new pacemaker implantation was only 8.9%.

Discussion

The study provides data on clinical outcomes of in-hospital, 30-day, 6- and 12-month follow-up after TAVI in our center. In our study, the all-cause mortality rate at 30 days remains below the estimated risk by logistic EuroSCORE I and STS score (10.9% vs. 14% and 12%, respectively), which is comparable to data published by other European TAVI centers [10–15]. This may be due to careful patient selection by the multidisciplinary Heart Team also in terms of the particular device and access site. All deaths within the first 30 days and 6 and 12 months following TAVI were due to cardiovascular causes. The incidence of in-hospital cerebrovascular incidents was comparable to rates reported in other registries. In Germany, periprocedural stroke after TAVI was reported in 1.7% to 2.3% [15], whereas the stroke rates in the French registry were 3.4% [11], and 4.1% in the UK [14]. A 30-day rate of 4.9% of cerebrovascular incidents is relatively high but still comparable with other data. Technological improvement, more standardized procedural techniques and cerebral protection during the procedure may help in reducing these disabling adverse events. However, recent studies evaluating cerebral protection devices have not shown any benefit [16]. The incidence of cerebrovascular events at 6 and 12 months was 7%, probably due to new onset of atrial fibrillation. The bleeding rate in the periprocedural period was relatively high, reaching 27.7%, with the need of red blood cell infusion in 25.7% of patients. This event rate is higher than previously published [10–15], and we thought it might have been a result of the operator’s learning curve and only associated with in-hospital course. However, we performed an additional data review and found that the majority of bleeding complications were associated with gastrointestinal tract bleeding, probably linked to anticoagulation/antiplatelet therapy. Bleeding complications and red blood cell transfusion may be linked with impaired outcome after TAVI [17]. Acute kidney injury was quite frequent in our cohort of patients after TAVI (69%); however, more than 60% of them had chronic renal failure at baseline. Dialysis was required in only 5% of subjects. Evidence on the safety and efficacy of TAVI in patients with acute kidney injury is incoherent. Data by Gargiulo et al. showed that postoperative acute kidney injury significantly increased early and 1-year all-cause and cardiovascular mortality, but also early myocardial infarction, life-threatening bleeding, need for transfusion, and dialysis [18]. However, in a study by Goebel et al., preoperative chronic kidney disease did not increase the risk of mortality and acute kidney injury after TAVI [19]. Paravalvular leak (PVL) also remains a significant complication associated with TAVI, which may cause higher mortality rates in a long-term follow-up [2]; however, there are some data suggesting no influence on the mid-term outcomes [20]. In our subset of patients, PVL was not a significant clinical issue. Pacemaker implantation following TAVI occurred in 15.8% of patients within 12 months, which is concordant with other data [21–25]. The in-hospital pacemaker implantation rate was 8.9%, so there is a constant need for performing scheduled follow-up visits for TAVI patients to diagnose and treat new conduction disturbances.
Our study had a relatively small sample size, which is a consequence of the limited reimbursement for TAVI in Poland overall. The results are influenced by operators’ learning curve for TAVI procedures. The completeness of follow-up is about 98%, and thus we cannot exclude underreporting of events.

Conclusions

The TAVI is a favorable treatment option for elderly patients with severe AS who are at a high risk for surgery. A mortality rate of < 20% after 12 months seems acceptable given the high-risk population enrolled.

Conflict of interest

The authors declare no conflict of interest.

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