B-type natriuretic peptide in patients after percutaneous trans-coronary-sinus mitral annuloplasty

Functional mitral regurgitation (MR) remains a significant clinical problem. Surgical valve repair carries a high procedural risk. Thus, percutaneous techniques are under development. One of the most advanced devices for percutaneous mitral annuloplasty (PTMA) is the Carillon™ device. B-type natriuretic peptide (BNP) is a marker of haemodynamic status in heart failure patients. So far, its usefulness in patients after PTMA is unknown.

Thirteen consecutive patients after successful implantation of the Carillon™ device were enrolled. PTMA was achieved through the coronary sinus in order to improve leaflet coaptation. Before PTMA, immediately after, and at one month follow-up, transthoracic echocardiography was performed. Furthermore, plasma BNP levels, the six-minute walk test (6MWT) and the Naughton treadmill exercise test were evaluated before PTMA and after one month.

In patients after successful PTMA, significant improvement in echocardiographic parameters was maintained at one-month follow-up: vena contracta (0.31 ± 0.03 vs. 0.64 ± 0.03 cm, p < 0.05), effective regurgitant orifice area (0.2 ± 0.02 vs. 0.32 ± 0.05 cm², p < 0.05), MR jet area/left atrial area (32.33 ± 1.98 vs. 47.06 ± 2.3%,p < 0.05) and regurgitant volume (27.84 ± 2.17 vs. 45.25 ± 7.47 mL, p < 0.05). Both the duration of the exercise test (4.3 ± 0.45 vs. 3.12 ± 0.18 min, p < 0.05) and 6MWT (320 ± 29.63 vs. 295.2 ± 13.4 m, p < 0.05) improved. Furthermore, improvement of the NYHA class was observed. Despite that, mean BNP levels remained unchanged (405.3 ± 133.9 vs. 596.5 ± 245.2 pg/mL, p = 0.191; after and before the procedure, respectively). In some patients with device located above the annulus level, an increase in BNP leve ls was observed.

BNP seems to be useless for the assessment of patients after PTMA. This may be related to mechanical stress on the annulus and atrial wall caused by the device itself.