Abstract: We identified four studies (13 reports), with 2818 participants, and one ongoing study. Overall certainty of evidence ranged from high to very low. There is probably little or no difference between TAVI and SAVR for the following short-term outcomes: all-cause mortality (RR 0.69, 95% CI 0.33 to 1.44; SAVR 11 deaths per 1000, TAVI 8 deaths per 1000 (95% CI 4 to 16); 2818 participants; 4 studies; moderate-certainty evidence); stroke (RR 0.73, 95% CI 0.42 to 1.25; SAVR 21 strokes per 1000, TAVI 16 strokes per 1000 (95% CI 9 to 27); 2818 participants; 4 studies; moderate-certainty evidence); MI (RR 0.82, 95% CI 0.42 to 1.58; SAVR 14 MI per 1000, TAVI 11 MI per 1000 (95% CI 6 to 21); 2748 participants; 3 studies; moderate-certainty evidence); and cardiac death (RR 0.71, 95% CI 0.32 to 1.56; SAVR 10 cardiac deaths per 1000, TAVI 7 cardiac deaths per 1000 (95% CI 3 to 16); 2818 participants; 4 studies; moderate-certainty evidence). TAVI may reduce the risk of short-term rehospitalisation, although the confidence interval also includes the possibility of no difference in risk between groups (RR 0.64, 95% CI 0.39 to 1.06; SAVR 30 cases per 1000, TAVI 19 cases per 1000 (95% CI 12 to 32); 2468 participants; 2 studies; low-certainty evidence). TAVI, compared with SAVR, probably increases the risk of PPM implantation (RR 3.65, 95% CI 1.50 to 8.87; SAVR 47 per 1000, TAVI 170 cases per 1000 (95% CI 70 to 413); number needed to treat for an additional harmful outcome (NNTH) = 7; 2683 participants; 3 studies; moderate-certainty evidence). We are uncertain whether TAVI, compared with SAVR, affects the LOS in days, although it appears to be associated with shorter LOS. TAVI, compared with SAVR, reduces the risk of atrial fibrillation (RR 0.21, 95% CI 0.15 to 0.30; 2683 participants; 3 studies), AKI (RR 0.30, 95% CI 0.16 to 0.58; 2753 participants; 4 studies), and bleeding (RR 0.31, 95% CI 0.16 to 0.62; 2753 participants; 4 studies) (all high-certainty evidence). Our meta-analysis indicates that, in the short term, TAVI probably has little or no mortality difference compared to SAVR for severe AS in individuals with low surgical risk. Similarly, there is probably little or no difference in risk of stroke, MI, and cardiac death between the two approaches. TAVI may reduce the risk of rehospitalisation, but we are uncertain about the effects on LOS. TAVI reduces the risk of atrial fibrillation, AKI, and bleeding. However, this benefit is offset by the increased risk of PPM implantation. Long-term follow-up data are needed to further assess and validate these outcomes, especially durability, in the low surgical risk population.

Plain-language summary: The four clinical trials included 2818 participants who were randomly allocated to undergo either TAVI or surgical aortic valve replacement (SAVR). The trials were multicentre and took place in Australia, Canada, France, Japan, the Netherlands, New Zealand, the USA, Denmark, and Sweden. Moderate-certainty evidence from clinical trials shows that, in the short term (i.e. during hospitalisation and up to 30 days of follow-up), there is probably little or no difference between TAVI compared with SAVR in risk of death due to any cause, stroke (insult to the brain), myocardial infarction (injury or death of heart muscle), or death due to cardiac causes (e.g. myocardial infarction or failure of the heart muscle pump). Low-certainty evidence shows that TAVI may reduce the risk of rehospitalisation compared with SAVR. We are uncertain whether TAVI, compared with SAVR, affects the length of hospital stay, although it appears to be associated with shorter duration of hospitalisation. High-certainty evidence shows that fewer people had atrial fibrillation (a type of irregular heart rhythm), acute kidney injury (insult to the kidney), and bleeding when they underwent TAVI, compared with SAVR. However, moderate-certainty evidence shows that TAVI probably increases the risk of permanent pacemaker implantation (a device that is placed to artificially set the heart rhythm), compared with SAVR. We consider the overall quality of evidence to be moderate for most relevant outcomes (death, stroke, myocardial infarction, cardiac death, and risk of permanent pacemaker implantation), with the exception of rehospitalisation (low-quality evidence) and length of hospital stay (very low quality evidence). The evidence for atrial fibrillation, acute kidney injury, and bleeding was of high quality.