Elderly patients with aortic stenosis and medium surgical risk experienced better than expected results after undergoing traditional surgical aortic valve replacement, according to research presented at the 53rd Annual Meeting of The Society of Thoracic Surgeons (STS; 21-25 January 2017, Houston, Texas).
“In an era that includes both surgery and transcatheter aortic valve implantation (TAVI), it is clear that the treatment for aortic stenosis has changed,” says Vinod H Thourani, from Emory University in Atlanta, USA, who led the study. “But even with the availability of the relatively new TAVI procedure, surgery remains a safe and effective way to treat aortic stenosis in intermediate-risk, elderly patients.”
Thourani and colleagues from 15 other institutions performed an in-depth analysis of surgical outcomes in patients who participated in the Placement of Aortic Transcatheter Valves (PARTNER-IIA) trial. In the PARTNER-IIA trial, conducted from December 2011 to November 2013, 1,011 severe aortic stenosis, intermediate-risk patients were randomised in 57 North American centres to surgery. Of these, 937 patients had surgical valve implantation and ultimately composed the study group for this research. The mean age was 82 years old, and 55% were male.
In their analyses, researchers found that the operative mortality was 4.1%, somewhat lower than the STS predicted risk models—a tool for surgeons to predict the patient risk of death or illness following open aortic valve replacement. “The outcomes in intermediate-risk patients who received surgery were excellent, showing that mortality is non-inferior to TAVI,” says Thourani. “This was better than expected.”
According to Thourani, approximately 15% of all patients undergoing surgery in the USA are categorised as intermediate risk. TAVI was approved in the USA in late 2011, providing an alternative therapy for high-risk patients with aortic stenosis who previously were refused surgery. Prior to TAVI, surgery was the only effective long-term therapeutic option for patients.
In addition to a lower than expected mortality rate from surgery, researchers were surprised to learn that prosthesis-patient mismatch was common, with 33% of patients receiving a surgical valve that was too small. However, according to Thourani, this did not affect the mortality. The study also showed a greater risk of in-hospital stroke among surgical cases. “In the past, there were no formal neurological assessments, meaning that previous rates possibly were understated,” explains Thourani. “The PARTNER-IIA study was one of the first times that neurological evaluations following the surgical procedure were conducted, so further research in this area is required.”
“Patients with aortic stenosis must realise how important it is that they are evaluated by a dedicated heart valve team that can help them understand the variety of options available and shepherd them into the most informed decision,” says Thourani.
Future research includes a randomised PARTNER-III study that will evaluate TAVI and surgery in low-risk patients.