Upsides, Downsides for TAVR, Minimally Invasive AVR

NEW YORK (Reuters Health) – Minimally invasive aortic valve replacement (miAVR) seems to be associated with a lower risk of midterm mortality, while transcatheter aortic valve replacement (TAVR) was associated with shorter hospitalizations and a lower risk of acute kidney injury (AKI) in a meta-analysis of matched cohort studies.

The authors highlight an “urgent need” for head-to-head randomized trials.

“Most of the available literature focuses on the comparison of TAVR and classic SAVR,” Dr. Abdelrahman Abushouk of Beth Israel Deaconess Medical Center and Harvard Medical School and Dr. Ahmed Bendary of Benha University in Egypt told Reuters Health in a joint email.

“No randomized trials have attempted to compare TAVR and miAVR, and observational studies have inherent biases,” they said. “We tried to perform a pooled analysis of only matched observational studies in an attempt to reduce potential bias.”

The significantly higher mid-term all-cause mortality with TAVR compared with miAVR “is consistent with longer term follow-up data from randomized controlled trials comparing TAVR to classic SAVR in either intermediate or even low surgical risk patients. The data showed that the large effect size favoring TAVR seen in the first year of follow-up wanes with time,” they said. “In other words, TAVR might be losing ground by years.”

That said, they added, “some caution should be exerted in interpreting these data, taking into consideration the observational nature of the included studies, and the potential for unmeasured confounders.”

As reported in Open Heart, the researchers searched the literature from 2002 (TAVR inception) through 2019 and identified 11 cohort studies, seven of which were matched or propensity matched.

As Drs. Abushouk and Bendary noted, higher rates of midterm (one year or more) mortality were seen with TAVR (risk ratio, 1.93). However, no significant differences between the two procedures were observed with respect to rates if one- month mortality (RR, 1.00), stroke (RR, 1.08) or bleeding (RR, 1.45).

TAVR patients were more likely to have paravalvular leakage (RR, 14.89), but less likely to experience acute kidney injury (RR, 0.38).

By contrast, the hospital length of stay was significantly longer for miAVR (mean difference, 1.92), although heterogeneity was high.

The quality of evidence was low-to-moderate for all outcomes, according to the Grading of Recommendations Assessment, Development and Evaluation assessment.

Overall, TAVR was associated with lower acute kidney injury rate and shorter length of hospitalization, yet higher risks of midterm mortality and paravalvular leakage.

The authors conclude, “Given the increasing adoption of both techniques, there is an urgent need for head-to-head randomized trials with adequate follow-up periods.”

Dr. Bendary said that, personally, he “would immediately…advocate TAVR for that older age patient with severe aortic stenosis (and) multiple comorbidities such as renal impairment and high bleeding risk. On the other hand, miAVR may be my way to go with a younger, healthier patient with severe aortic stenosis whose life expectancy is longer.”

Dr. Abushouk added, “A randomized controlled trial is needed comparing TAVR, classic SAVR, and miAVR, with powered subgroup analyses according to age, surgical risk, and access/incision site, as well as an extended follow-up to generate data on long-term outcomes of such comparisons.”

Dr. Sanjiv Patel, an interventional cardiologist at MemorialCare Heart and Vascular Institute at Orange Coast Medical Center in Fountain Valley, California, said he found it “interesting that the miAVR had a more favorable mortality rate.”

Like the authors, he noted in an email that a randomized controlled trial is needed to further investigate and validate the differences and efficacy between the two procedures.

“Until further data are available, low-risk patients can undergo either TAVR or miAVR,” he told Reuters Health. “However, for higher-risk patients, I believe transfemoral TAVR is the safest and most effective option.”

SOURCE: Open Heart, online January 17, 2021.

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