Good early outcomes have been seen for all patients undergoing TAVI (Transcatheter Aortic Valve Implantation), including low risk patients, in figures from Victorian centres.

The 30-day outcomes for 601 patients with severe symptomatic aortic stenosis who underwent TAVI at the Alfred and Epworth Hospitals in Melbourne between 2008 and 2018 were comparable to those seen in international cohorts, according to investigators led by Dr Ed Quine of the Cardiology Department, Alfred Hospital.

Their review included 285 patients classified as low risk by the Society of Thoracic Surgeons Predicated Risk of Mortality (STS-PROM) risk score (<4%), who showed a 1.1% mortality rates (compared to 1.7% for intermediate risk and 1.4% for high risk patients.

There were also low rates of disabling stroke (0.4%, 1.3%, 0%, respectively) across all risk groups.

Rates of post-procedural permanent pacemaker insertion were also similar (21%, 27%, 26%, p=0.5) between low medium and high risk patients.

“Rates of post-procedural pacemaker represent a significant ongoing hurdle for TAVI in low-risk populations,” the study authors noted.

Findings from other studies suggested that pacemaker insertion rates may be lower with balloon-expandable valves in young, low-risk patients but data is needed on  long-term outcomes and durability, they wrote in Heart, Lung and Circulation.

Moderate or severe aortic regurgitation occurred in 9% of low risk patients at discharge, similar to the rates seen in other risk groups.

The study authors said the outcomes compared well to those seen in international studies of TAVI in low risk patients such as the Placement of Aortic Transcatheter Valves (PARTNER 3) and Medtronic trials.

They said the results highlighted the drawbacks of the STS-PROM scoring system in pre-procedural assessment for TAVI patients, given the significant difference in expected versus observed mortality.

The STS-PROM score may be more accurate in high-risk populations, but its overestimation of predicted mortality in low risk patients shows that better risk stratification tools are needed that incorporate additional factors such as frailty, they said.

The excellent outcomes also supports the ongoing use of the Heart Team model of patient selection for TAVI procedures, in order to account for features not currently included in risk prediction scores.

In the Australian cohort the average age of patients was 84 years, and most underwent TAVI with self-expanding devices (82%) rather than balloon expandable valves.