Data from the new CoreValve study underscore how limited the STS PROM score is right now. The average score of the patients enrolled in the surgical arm of this study was 7.5%, which means that 7.5 % of the patients who underwent SAVR were predicted by the scoring system to die during the first 30 days after surgery. But the actual rate was 4.5%, "substantially lower," said the CoreValve report. STS PROM scoring resulted in a substantial overcall on predicted risk.
When TAVR was first introduced, experts had two caveats about its potential to completely replace SAVR. The first was uncertainty about the long-term durability (think 10 or more years) of TAVR. The second was uncertainty about the short- and intermediate-term safety and efficacy of TAVR, especially for the patients for whom conventional SAVR was a reasonable option.
Doubts about short- and intermediate-term efficacy arose with the first-generation TAVR device, Sapien, because of the issue of paravalvular leak and the inability of TAVR to surpass SAVR outcomes in the PARTNER I results, but those doubts have now been mostly swept away from by the CoreValve results, which established CoreValve as superior to SAVR and made it the current standard for essentially all patients who need their aortic valve replaced. Even if paravalvular leak is still an issue for some patients, patients treated with CoreValve, TAVR overall did significantly better after 1 year than SAVR in the CoreValve trial, which means that TAVR was best regardless of whether paravalvular leak was an issue for some patients. And this was in patients who represented a wide range of STS PROM risk, with close to 10% of enrolled patients having a score of less than 4%. A subanalysis showed that the low-risk patients derived as much benefit from CoreValve TAVR, compared with SAVR, as did higher-risk patients.
The long-term durability question still remains for now, but the substantial mortality benefit in the CoreValve trial seen after 1 year probably trumps that.
Researchers designed the TAVR trials to methodically progress through a spectrum of patient risk levels. As recently as a year ago, several experts told me that no way in the near future could TAVR be an option for low-risk patients with STS PROM scores of less than 4%. But that is not how it has worked out. Patients, cardiac surgeons, and cardiologists embraced TAVR way faster and tighter than anyone expected just a few years ago.
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