2.1 Patient Population and Study Design
Between March 2010 and June 2018, 181 consecutive patients who underwent
MVR with a bioprosthetic valve were identified from the institutional
database at Saitama Medical Center, Jichi Medical University. As per the
inclusion criteria, we included patients who underwent bioprosthetic MVR
with or without concomitant procedures. We excluded 53 patients in whom
the dominant valve dysfunction was MS, and those without preoperative or
postoperative echocardiographic data were missing. Finally, 128 patients
were included. The patient’s medical records were reviewed. Emergency
surgery was defined as an operation performed within 24 hours of
hospitalization.
Doppler transthoracic echocardiography was performed at discharge. The
estimated EOA of the implanted mitral valve was calculated using the
formula: 220/pressure half-time (PHT). The effective orifice area index
(EOAI) was defined as the bioprosthetic EOA/body surface area (BSA), and
PPM was defined as an EOAI was ≤ 1.2
cm2/m2, as described in the previous
report.12
Follow-up data were obtained from the clinical records or via telephone
interview. The follow-up rate was 98.4%; the patient status was
confirmed in 126 patients at least 1 year postoperatively, excluding
those who died within a year postoperatively. The mean follow-up period
was 4.4 ± 2.2 years. The study protocol was approved by the
Institutional Review Board of Jichi Medical University (January 15 2020,
S19-123).