In Degenerative Mitral Stenosis Stroke Risk is Higher for Patients Without AF

There is increased risk for stroke or systemic embolism in patients with degenerative mitral stenosis without atrial fibrillation.

A study published in IJC Heart & Vasculature found that patients with degenerative mitral stenosis without atrial fibrillation (AF) are at highest risk for stroke or systemic embolism.

Data for this study were sourced from health registries in Denmark. Patients (N=1162) who were diagnosed with degenerative mitral stenosis between 1997 and 2018 were evaluated for ischemic stroke or systemic embolism risk.

The included patients had a mean age of 69.9 (SD, 14.8) years, 71.2% were women, average CHA2DS2-VASc score was 3.5 (SD, 1.9), and 11.4% had a prior stroke or systemic embolism. A subset of 36.2% of patients had co-occurring AF. The AF cohort was older, more had comorbidities, they had higher CHA2DS2-VASc scores, and more took anticoagulants and vitamin K antagonists compared with the patients without AF.

During the first year after degenerative mitral stenosis diagnosis, the incidence rate (IR) of ischemic stroke or systemic embolism was higher for the subgroup without AF (IR, 7.58 vs 6.63 per 100 person-years) whereas the all-cause mortality rate was lower (IR, 17.0 vs 27.28 per 100 person-years) compared with the AF group, respectively.

After the initial year, the IRs of ischemic stroke or systemic embolism were 5.15 per 100 person-years for both patients with and without AF who did not have a prior thromboembolic (TE) event compared with 29.61 per 100 person-years for patients without AF and a prior TE event and 19.53 per 100 person-years for those with AF and a prior TE event. The all-cause mortality rate was lowest for the patients without AF with a prior TE event (IR, 10.39 per 100 person-years), followed by patients without AF and no prior TE event (IR, 17.86 per 100 person-years), patients with AF and no prior TE event (IR, 25.22 per 100 person-years), and patients with AF and a prior TE event (IR, 44.25 per 100 person-years).

As current guidelines recommend that DMS patients should be treated with anticoagulation only with concurrent AF, our results call for additional studies to establish if DMS patients without AF could benefit from stroke prevention therapy.

Stratified by treatment recommendations based on CHA2DS2-VASc scores, patients in the no treatment indication group who did not have AF had an IR for ischemic stroke or systemic embolism of 4.39 per 100 person-years, which was higher than the patients with AF who fit the criteria for treatment consideration (IR, 2.07 per 100 person-years).

In a sensitivity analysis that used a 10-day quarantine period between degenerative mitral stenosis diagnosis and follow-up, similar trends were observed.

The findings of this study may be limited by not having access to data about severity of mitral stenosis.

These data indicated that stroke risk was highest for patients with degenerative mitral stenosis who did not have co-occurring AF. The study authors wrote, “As current guidelines recommend that DMS [degenerative mitral stenosis] patients should be treated with anticoagulation only with concurrent AF, our results call for additional studies to establish if DMS patients without AF could benefit from stroke prevention therapy.”

Disclosure: Multiple authors declared affiliations with industry. Please refer to the original article for a full list of disclosures.

References:

Steiner DK, Søgaard P, Jensen M, Larsen TB, Lip GYH, Nielsen PB. Risk of stroke or systemic embolism in patients with degenerative mitral stenosis with or without atrial fibrillation: a cohort study. Int J Cardiol Heart Vasc. Published online October 7, 2022. doi:10.1016/j.ijcha.2022.101126