Transcatheter Aortic Valve Implantation (TAVI): Is it Time for This Intervention to be Applied in a Lower Risk Population?

Conundrum of Classifying Subtypes of Pulmonary Hypertension-Introducing a Novel Approach to Classify "Borderline" Patients in a Population with Severe Aortic Stenosis Undergoing TAVI

Background: Transcatheter aortic valve implantation (TAVI) is an established therapeutic option in patients with severe aortic valve stenosis (AS) and a high surgical risk profile. Pulmonary hypertension (PH)—often co-existing with severe AS—is associated with a limited factor for prognosis and survival. The purpose of this study was to evaluate the prevalence of PH in patients undergoing TAVI, classify these patients based on right heart catheter (RHC) measurements in different PH subtypes, and analyze prognostic values on survival after TAVI. Methods: 284 patients with severe AS underwent an RHC examination for hemodynamic assessment prior to TAVI and were categorized into subtypes of PH according to the 2015 European Society of Cardiology (ESC) guidelines. TAVI patients were followed-up with for one year with regard to 30-days and 1-year mortality as primary endpoints. Results: 74 of 284 participants showed a diastolic pressure gradient (DPG) < 7 mmHg and a pulmonary vascular resistance (PVR) > 3 Wood units (WU) and could not be formally allocated to either isolated post-capillary PH (ipc-PH) or combined pre- and post-capillary PH (cpc-PH). Therefore, a new subgroup called “borderline post-capillary PH” (borderlinepc-PH) was introduced. Compared with TAVI patients with pre-capillary PH (prec-PH), ipc-PH patients suffering from borderlinepc-PH (HR 7.114; 95% CI 2.015−25.119; p = 0.002) or cpc-PH (HR 56.459; 95% CI 7.738−411.924; p < 0.001) showed a significantly increased 1-year mortality. Conclusions: Postcapillary PH was expanded to include the so-called “borderlinepc-PH” variant in addition to the ipc-PH and cpc-PH subtypes. The one-year survival after TAVI was significantly different between the subgroups, with the worst prognosis for borderlinepc-PH and cpc-PH.

Insulin like growth factor binding protein 2 (IGFBP-2) for risk prediction in patients with severe aortic stenosis undergoing Transcatheter Aortic Valve Implantation (TAVI)

INTRODUCTION

Severe aortic stenosis (AS) caused by degenerative calcification is the most frequent acquired valvular heart disease worldwide and mortality rates are considerably high. Transcatheter Aortic Valve Implantation (TAVI) is a well-established method for valve replacement in high risk patients with AS. However, there is a lack of reliable predictors for patients undergoing TAVI since commonly used scores were developed for surgical populations.

MATERIALS AND METHODS

208 patients subjected to TAVI were included in this study. Plasma samples were obtained before TAVI and were evaluated for IGFBP-2 using commercially available ELISA kits. IGFBP-2 levels were analyzed for their ability for risk prediction after TAVI.

RESULTS

IGFBP-2 levels measured before TAVI correlated significantly with left ventricular ejection fraction, EUROSCORE and other functional and prognostic parameters like the 6-minute walking test. When patients were retrospectively divided in two groups with a cut-off of serum IGFBP-2 levels of 275 ng/ml, IGFBP-2 was a strong predictor for 30-day and one-year mortality (3% vs. 11%, p = 0.05 and 18.2% vs. 46.2%; p < 0.001 respectively). Compared to an EUROSCORE above 20 or an STS score cut-off above 8, IGFBP-2 plasma levels above 275 ng/ml outperformed the established risk score for prediction of one-year mortality as assessed by NRI (0.65 95% CI 0.37-0.94; p < 0.001 and 0.54 95% CI 0.25-0.82; p < 0.001, respectively).

CONCLUSIONS

Our results indicate that IGFBP-2 could serve as new outcome predictor for patients undergoing TAVI procedure. By providing additional information to the commonly used EUROSCORE, IGFPB-2 analysis could further assist Heart Team decision making.

Temporal Trends and Clinical Consequences of Wait Times for Transcatheter Aortic Valve Replacement

Background:

Transcatheter aortic valve replacement (TAVR) represents a paradigm shift in the therapeutic options for patients with severe aortic stenosis. However, rapid and exponential growth in TAVR demand may overwhelm capacity, translating to inadequate access and prolonged wait times. Our objective was to evaluate temporal trends in TAVR wait times and the associated clinical consequences.

Methods:

In this population-based study in Ontario, Canada, we identified all TAVR referrals from April 1, 2010, to March 31, 2016. The primary outcome was the median total wait time from referral to procedure. Piecewise regression analyses were performed to assess temporal trends in TAVR wait times, before and after provincial reimbursement in September 2012. Clinical outcomes included all-cause death and heart failure hospitalizations while on the wait list.

Results:

The study cohort included 4461 referrals, of which 50% led to a TAVR, 39% were off-listed for other reasons, and 11% remained on the wait list at the conclusion of the study. For patients who underwent a TAVR, the estimated median wait time in the postreimbursement period stabilized at 80 days and has remained unchanged. The cumulative probability of wait-list mortality and heart failure hospitalization at 80 days was ≈2% and 12%, respectively, with a relatively constant increase in events with increased wait times.

Conclusions:

Postreimbursement wait time has remained unchanged for patients undergoing a TAVR procedure, suggesting the increase in capacity has kept pace with the increase in demand. The current wait time of almost 3 months is associated with important morbidity and mortality, suggesting a need for greater capacity and access.

Transcatheter vs. surgical aortic valve replacement and medical treatment : Systematic review and meta-analysis of randomized and non-randomized trials

BACKGROUND

Transcatheter aortic valve replacement (TAVR) has emerged as the procedure of choice for patients with severe aortic stenosis (AS) and high perioperative risk. We performed a meta-analysis to compare the mortality related to TAVR with medical therapy (MT) and surgical aortic valve replacement (SAVR).

METHODS

A systematic literature search was conducted by two independent investigators from the database inception to 30 December 2014. Relative risk (RR) and odds ratio (OR) were calculated and graphically displayed in forest plots. We used I ² for heterogeneity (meta-regression) and Egger's regression test of asymmetry (funnel plots).

RESULTS

We included 24 studies (n = 19 observational studies; n = 5 randomized controlled trials), with a total of 7356 patients in this meta-analysis. Mean age had a substantial negative impact on the long-term survival of AS patients (OR = 1.544; 95% CI: 1.25-1.90). Compared with MT, TAVR showed a statistically significant benefit for all-cause mortality at 12 months (OR = 0.68; 95% CI: 0.49-0.95). Both TAVR and SAVR were associated with better outcomes compared with MT. TAVR showed lower all-cause mortality over SAVR at 12 months (OR = 0.81; 95% CI: 0.68-0.97). The comparison between SAVR and TAVR at 2 years revealed no significant difference (OR = 1.09; 95% CI: 1.01-1.17).

CONCLUSION

In AS, both TAVR and SAVR provide a superior prognosis to MT and, therefore, MT is not the preferred treatment option for AS. Furthermore, our data show that TAVR is associated with lower mortality at 12 months compared with SAVR. Further studies are warranted to compare the long-term outcome of TAVR versus SAVR beyond a 2-year follow-up period.

Soluble ST2 predicts 1-year outcome in patients undergoing transcatheter aortic valve implantation

BACKGROUND

Soluble ST2 (sST2) has been introduced as a novel biomarker in patients suffering from heart failure for risk stratification. In this study, we sought to investigate whether sST2 is useful for risk stratification and prediction of mortality in patients undergoing transcatheter aortic valve implantation (TAVI).

MATERIALS AND METHODS

A total of 274 patients undergoing TAVI were included in this study (149 female; age 81 ± 1 years; EUROSCORE 25 ± 1; STS score 3·8 ± 0·2). Plasma samples were obtained preinterventional and analysed for sST2. Patients were followed up 1 month and 1 year after TAVI.

RESULTS

In a Cox regression analysis, sST2 plasma concentration was associated with increased mortality (changes per pg/mL sST2 concentration; HR 1·00006 95% (1·00004-1·00009); P < 0·001). A cut-off by means of the Youden Index was calculated (10 070·27 pg/mL), and patients were retrospectively divided into two cohorts, in those above (31·3%) and those below (68·7%) this value. These two groups were then compared regarding mortality both after 30 days and 1 year: whereas 1-month mortality did not differ (7·0% vs. 10·3%, OR 1·50 95% CI (0·60-3·79; P = 0·46)), patients with a sST2 concentration above the cut-off of 10 070·27 pg/mL showed a significantly worse outcome after 1 year (49·2% vs. 23·2%; OR 3·21 95% CI (1·70-6·04); P < 0·001). After correction for confounders in a multivariate Cox regression analysis, sST2 (1·0002 95% CI (1·0001-1·0003); P = 0·001) concentration remained associated with mortality.

CONCLUSIONS

sST2 levels were associated with 1-year mortality after TAVI. Based on these results, we assume that sST2 might help to identify patients at high risk for death in whom conservative treatment should be considered.