SWEDEHEART Affirms SAVR’s Long-term Benefits in Young, Low-Risk AS

An analysis of the SWEDEHEART registry supports current guideline recommendations that surgical management is appropriate and has long-term benefits for young patients with aortic stenosis and low surgical risk.

“I think the most important takeaways from the study are that for younger, low-risk patients there is a substantial median survival after SAVR, eg > 10 years in low-risk patients aged 75-79 years, while age does not seem to be as important for survival in intermediate- and high-risk patients,” Andreas Martinsson, MD, PhD (Sahlgrenska University Hospital, Gothenburg, Sweden), the study’s lead author, said in an email. “This information is important for heart-team discussion given that the overall long-term follow-up after TAVR is restricted, especially in pure low-risk populations.”

Issues surrounding life expectancy in relation to age, surgical risk, and prosthesis longevity are becoming more important for decision-making. A recent Swedish registry study found a median survival time in SAVR patients of approximately 9.5 years, with significant variations by age. Another study of SAVR patients in the United Kingdom reported survival of 15 years in those 65 to 69 years of age, 10.6 years in those 70 to 79 years, and 6.3 years in those aged 80 or older. The new findings are in line with current guidelines. The European Society of Cardiology/European Association for Cardio-Thoracic Surgery recommend SAVR in low-risk patients under age 75, while the American Heart Association/American College of Cardiology recommend surgery in those under age 65 or with a life expectancy of more than 20 years.

In an accompanying editorial in the Journal of the American College of Cardiology, Natalie Glaser, MD, PhD (Stockholm South General Hospital, Sweden), says the study by Martinsson and colleagues “confirms the excellent long-term survival after SAVR, especially in younger and low-risk patients.”

Commenting for TCTMD, Hemal Gada, MD (UPMC Pinnacle, Harrisburg, PA), added that the findings validate the practice of the heart team, particularly the growing importance of lifetime management.

“As the study suggests, the majority of people that have severe aortic stenosis and need treatment would be defined as 'low risk.' If they're low-risk patients and under the age of 70, then you have to think about lifetime implications of the valves,” he said. “You have to think about what is repeat TAVR, repeat surgical management, going to look like down the road.”

Gada added that the data are welcome given that the evidence base for both SAVR and TAVI is deficient with regards to longer-term follow-up of low-risk cohorts.

Good Survival in Young, Low-Risk Patients

For their study, Martinsson and colleagues analyzed data on 8,353 patients age 60 years and older enrolled in the SWEDEHEART registry who underwent isolated SAVR between 2001 and 2017 and were classified prior to surgery as low-, intermediate-, or high-risk using either the logistic EuroSCORE or EuroSCORE II. Overall, 85% of patients were in the low-risk category.

Median survival was 10.9 years among those at low risk, 7.3 years for those at intermediate risk, and 5.8 years for those at high risk. In Kaplan-Meier analysis, cumulative 5-year mortality rates were 16.5% for low risk, 30.7% for intermediate risk, and 43% for high risk. A sensitivity confirmed the results of the primary analysis.

Looking at survival in relation to risk and age showed a median survival time of approximately 16 years in low-risk patients on the lower end of the age spectrum (60 to 64 years), compared with 6 years among those 85 and older. Similarly, cumulative 5-year mortality was much lower in the younger low-risk patients at 6.8%, compared with 37.7% in those 85 and over.

Among patients at low surgical risk, age was associated with 5-year mortality (HR 1.30 per 5-year increase; 95% CI 1.23-1.37), whereas it was not in the intermediate- (HR 1.04; 95% CI 0.93-1.16) or high-risk patients (HR 1.01; 95% CI 0.87-1.18). A regression analysis of low-risk patients who were age- and sex-matched to high- and intermediate-risk patients, was consistent with the findings of the primary analysis (P < 0.001).

Additionally, analysis by gender of the entire cohort found a mild female survival advantage (10.3 years vs 10 years in men; P = 0.004). The finding remained consistent regardless of surgical risk group.

Considering Both Evidence and Preference

To TCTMD, Martinsson said it is important that patients are involved in the decision-making process, and that they are well-informed about the pros and cons of TAVI and surgery.

“It is important that the patients understand the currently available evidence (or lack thereof) so that they, together with the physician, can make the best choice,” he added.

Gada agreed, adding that it’s also often necessary to dissect out what is driving patient preference, particularly with regard to those who are young, low risk, but adverse to surgery.

“Is it a fear of surgery, or is there actually some sort of quality-of-life implication that they are thinking about, and is it valid?” he said. For many patients the answer may be yes. “The impact of the surgical intervention is actually more significant in someone that is otherwise completely healthy. You're basically taking someone with a good quality-of-life and reducing them down to whatever utility a postsurgical state gives them, which is a much larger decrement than it would be for someone who's intermediate or high risk [and] has a host of comorbidities.”

Glaser notes that while the study by Martinsson and colleagues “conveys important information,” large RCTs comparing TAVI and SAVR in low-risk patients, including PARTNER, PARTNER 2, and PARTNER 3, used Society of Thoracic Surgery-Predicted Risk of Mortality (STS-PROM) to assess surgical risk rather than EuroSCORE, making a comparison between those studies and the current SWEDEHEART analysis not possible.

Gada said while the scores each have a role and are important, surgical risk is less and less being viewed by those numbers alone.

“We look at a whole host of different things, including the frailty assessment, including their age. This study validates that practice and shows that it definitely matters,” he said.