TAVI vs Minimally Invasive AVR Yields Surprising Findings: Meta-analysis

Compared with minimally invasive aortic valve replacement (miAVR) surgery, TAVI is associated with lower rates of acute kidney injury (AKI) and shorter hospitalizations, but higher rates of midterm mortality and paravalvular leak, according to a new meta-analysis.

“Most of the available literature focuses on the comparison of TAVR and classic SAVR,” senior author Abdelrahman Abushouk, MD (Beth Israel Deaconess Medical Center, Boston, MA), told TCTMD in an email. “No randomized trials have attempted to compare TAVR and miAVR and observational studies have inherent biases.”

“The present study is the first of its kind in the literature that pooled data comparing TAVR versus miAVR with a higher degree of certainty and statistical power,” study co-author Ahmed Bendary, MD (Benha University, Egypt), added. “Our results, albeit not necessarily practice-changing, will of course help the interventional cardiologists, surgeons, and the heart team as a whole in deciding on the best option for each individual patient with AS through an informed [discussion using] best-attainable evidence.”

The findings were published online this week in Open Heart, with lead author Ahmed Sayed, MD (Ain Shams University, Cairo, Egypt).

Higher Midterm Mortality for TAVI

For the analysis, the investigators included 11 cohort studies spanning 2009 to 2019 comparing TAVI with minimally invasive AVR only, seven of which were either multivariate or propensity-matched. The final study cohort consisted of 4,674 patients (mean 82 years) undergoing either TAVI (n = 2,346) or minimally invasive AVR (n = 2,328) and followed for an average of 26.7 months.

Among five studies with available data, there were no differences observed between the procedures for 30-day mortality, but midterm mortality (defined as follow up of at least 1 year) was higher for TAVI among data from four studies. TAVI showed more paravalvular leak in five studies, less AKI in four studies, and shorter hospital length of stay in six studies. Additionally, there were no differences observed for stroke and major bleeding.

TAVI vs Minimally Invasive AVR Outcomes

*Mean difference

Initially, the researchers observed no difference in AF between TAVI and minimally invasive AVR, but found less postoperative AF when looking solely at transfemoral TAVI, a group in which newer-generation valves were more prevalent, “though heterogeneity was still high” (RR 0.14; 95% CI 0.04-0.48).

Call for More Randomized Data

Bendary said one of the most notable findings from the study was the higher rate of midterm mortality for TAVI over surgery. “This is consistent with longer-term follow-up data from RCTs comparing TAVR to classic SAVR in either intermediate- or even low-surgical-risk patients, which showed that the large effect size favoring TAVR seen in the first year of follow-up wanes with time,” he said in an email. “In other words, TAVR might be losing ground” as the years go by.

At this point, however, Bendary said he would choose TAVI “for that older age patient with severe AS who [has] multiple comorbidities, such as renal impairment and high bleeding risk. On the other hand, minimally invasive AVR may be my way to go with a younger healthier patient with severe AS whose life expectancy is expectedly longer.”

“Although the surgical risk stratification still plays a role in patient selection, TAVR is rapidly moving towards the low-surgical-risk category,” Abushouk added. “Its comparative outcomes to minimally invasive AVR in these patients are still to be determined. One of the main recommendations of our article is a call to develop evidence-based criteria to determine which patients, especially those of young age, may benefit from either procedure.”

Commenting on the study for TCTMD, Vinod Thourani, MD (Piedmont Heart Institute, Atlanta, GA), said the results are difficult to interpret given the design of the retrospective analysis. “Propensity matching patients who are not candidates for surgery, be it open or minimally invasive, is fraught with equipoise in the exact patient populations that are compared,” he commented. “The main rationale is that the TAVR patients were considered to not be good candidates for surgery. Therefore, despite their STS scores, [they] have comorbidities that have excluded them from surgical therapy.”

The researchers advocate for the need for future randomized trials comparing TAVI to minimally invasive AVR alone “given the increasing adoption of both techniques.”

Yet, Bendary said that comparison is unlikely to happen. “Do you think in a world of a driving force for augmented benefit, that industry providing transcatheter valves would be interested in funding a trial comparing two less-invasive approaches for treating patients with severe AS? I don't think so.”

Thourani agreed, noting that an unpublished PARTNER 3 substudy looking at minimally invasive versus open surgery showed no differences in outcomes. “And, moreover, transfemoral TAVR in low-risk patients still did better than minimally invasive.” Further long-term TAVI data are warranted, however, he added.

Nonetheless, Abushouk said future successful patient outcomes will rely upon “collaboration between professional societies and using the heart team approach.”