TAVI delivers positive mid-term outcomes in Asian patients
Asian patients undergoing transcatheter aortic valve implantation (TAVI) show favourable mid-term clinical and safety outcomes despite their unique clinical characteristics, according to a Singapore study. These outcomes are also comparable with well-established European and North American studies.
“Multiple Western studies have also proposed that TAVI … is more cost-effective [than surgical aortic valve replacement (SAVR)] in high-risk or inoperable patients, and future trials are needed to determine if this holds true for the Asian population,” researchers said. [Circulation 2012;125:1102-9]
A total of 59 patients (mean age 76.8 years; 61.0 percent male) from a major academic medical centre in Singapore were recruited in this prospective study. Their mean body surface area was 1.6 m2 and mean logistic EuroSCORE was 18.7 percent. The primary outcomes were 2-year survival rates, periprocedural complications, symptom improvement, valvular function and assessment of learning curve.
Patient survival was 93.2 percent at 30 days, 86.0 percent at 1 year and 79.1 percent at 2 years. At 30 days following TAVI, the rates of stroke, life-threatening bleeding, acute kidney injury, major vascular complication and new permanent pacemaker implantation were 1.7, 5.1, 25.0, 5.1 and 6.8 percent, respectively. Within 1 year, 29.3 percent of patients were rehospitalized, and 47.1 percent of these were cardiovascular-related. [Singapore Med J 2017;58:543-550]
The rates of composite outcomes were as follows: device success 93.2 percent, early safety 79.7 percent, clinical efficacy 66.1 percent and time-related valve safety 84.7 percent.
Univariate analysis revealed that logistic EuroSCORE (hazard ratio [HR], 1.07; p<0.001), baseline estimated glomerular filtration rate (HR, 0.97; p=0.048) and acute kidney injury (HR, 5.33; p=0.022) predict 2-year all-cause mortality. Furthermore, multivariate analysis found nontransfemoral (non-TF) TAVI as a predictor of cardiovascular-related 2-year mortality (HR, 14.64; p=0.008).
“Overall, this study has demonstrated that TAVI provides good mid-term outcome data and symptomatic improvement, with comparable procedural complication rates, for Asian patients,” researchers said. “With the ongoing development of smaller TF-TAVI delivery sheaths, the risk of vascular complications may be further reduced.”
Also, the risk of paravalvular (PVL) leak may be reduced with the increasing use of three-dimensional computed tomography measurement of aortic annulus, together with enhanced delivery systems that allow for repositioning of the valve for optimized valve placement, and the development of novel TAVI valves with special sealing cuffs and skirts. [Eur Heart J 2016;37:803-10]
“In the SAPIEN 3 observational study … the propensity score analysis demonstrated that TAVI was superior to SAVR in the primary composite outcomes of mortality, strokes, and moderate or severe aortic regurgitation. This is encouraging, as it suggests that TAVI may also be a suitable alternative for intermediate-risk patients,” researchers said. [Lancet 2016;doi:10.1016/S0140-6736]
The current study has several limitations, including its small sample size that provided low statistical power and its failure to determine whether TF access or non-TF access was safer, as this was not a randomized controlled trial. Likewise, researchers could not conclude if patients preferred TAVI over SAVR in terms of safety and efficacy. No independent clinical events committee was also present to evaluate the outcomes of the study.
“In addition, no echocardiography core laboratory was used in the study; thus, all echocardiographic data was site-reported, which may increase the risk of measurement bias. Furthermore, it was challenging to assess the severity of PVL using transthoracic echocardiography,” researchers said.
“Lastly, although TAVI is a less invasive treatment for severe AS, no quality-of-life data was obtained. Nevertheless, we did use the conventional NYHA classification to monitor improvement in symptoms,” they added.