Diving deeper into the ABYSS trial, a new sub-analysis suggests that patients with MI and preserved LVEF who stop taking their beta-blockers experience significant rises in heart rate and BP, potentially increasing their risk of adverse events.
- Beta-blockers are still widely considered standard care post-MI, but many physicians wonder if the evidence supporting their use is out of date, prompting the ABYSS trial.
- ABYSS (n=3.7k) was an RCT originally designed to show that post-MI patients could safely stop taking their beta-blockers.
- The trial’s original results failed to prove noninferiority compared to continued treatment, supporting a “better safe than sorry” approach to beta-blockers post-MI.
Now ABYSS’ new sub-analysis gives insights as to why beta-blockers help reduce adverse outcomes post-MI by examining the differences in blood pressure and heart rate before and after discontinuing the drugs.
- The average resting heart rate was 63 bpm at baseline and increased by ~10 bpm after stopping treatment.
- Stopping beta-blockers also increased blood pressure by 3.7 mmHg for systolic and 3.3 mmHg for diastolic from baseline after six months.
While those differences don’t seem huge, they add up over time, especially for a heart already weakened by MI, and the effects of stopping beta-blockers were even more pronounced in the trial’s hypertension subgroup (n=1.6k).
- For hypetensive patients who kept taking beta-blockers, the composite rate of death, MI, stroke, or CV rehospitalization was 21.7% compared to 25.4% in those who stopped at four years.
- In patients without hypertension, the composite was in 17.4% of those who continued treatment and 19.5% of those who stopped.
So is there an argument to discontinuing beta-blockers after a while? Some doctors say improving patient quality of life is part of it, but it’s worth noting that ABYSS examined this too and found no improvement in quality of life after stopping.
The Takeaway
Researchers might have originally ventured into the ABYSS trial looking for proof that we can say goodbye to beta-blockers sooner, but this sub-analysis supports the opposite, and it seems like the benefits justify their long-term prescription after all.
