Results
Baseline characteristics
The baseline data of the patients were shown in Table 1. Compared with
the mechanical MVR group, the bioprosthetic MVR group had a larger left
atrium (49.5 [IQR, 46.0-55.5]mm vs. 46.0 [IQR, 40.3-48.9]mm,
p<0.05), a larger thickness of the left interventricular
septum (11.0 [IQR, 10.0-11.8]mm vs. 10.0 [IQR, 9.0-10.8]mm in
the mechanical MVR group, p<0.05), and a smaller mitral ring
area (2.3 [IQR, 2.0-2.6]mm2vs. 2.6[IQR,
2.4-2.9]mm2, p<0.05). There were no
significant differences in left ventricular ejection fraction, left
ventricular end-diastolic diameter and left ventricular end-systolic
diameter between the two groups. There were no statistically significant
differences in gender, age, blood pressure, BMI, laboratory parameters
and co-morbidities between the two groups.
Electrophysiology study and ablation
The ablation strategies and results of the two groups were shown in
Table 2. In the bioprosthetic MVR group, all the 12 patients underwent
CPVA. The bilateral PVI rate was 100%. Seven patients underwent MI
ablation with bidirectional MI block in 5 of the 7 patients (71.4%).
Nine patients underwent CTI ablation with a 100% CTI block rate. In the
mechanical
MVR group, all the 58 patients underwent CPVA. Bilateral PVI was
achieved in all the patients. MI ablation was performed in 36 cases
(64.3%). Bidirectional MI block was achieved in 21 of the 36 cases
(58.3%). Unidirectional mitral block was achieved in one case, and MI
block was not verified in one case. Forty-seven patients (83.9%)
underwent CTI ablation, bidirectional CTI line block was achieved in
44/47 (93.6%) patients. CTI block was not verified in one case. The
prevalence of ethanol infusion in vein of Marshall was significantly
higher in the bioprosthetic MVR group than in the mechanical MVR group
(33.3%vs.0.0%, p<0.001). There was no significant difference
of MI block rate between the two groups. There were 2 cases (3.4%) of
pseudoaneurysm and 1 case of acute cerebral infarction in the
mechanical
MVR group. No complication was observed in the bioprosthetic MVR group.
Follow-up results
After a follow-up of median 23.4 (6.1, 36.5) months, the incidence of
the endpoint events (33.3% vs. 30.4%) was not significantly different
between the two groups (log-rank p = 0.48, Fig.1). One case (8.3%) had
early recurrence in the bioprosthetic MVR group, and two cases (3.4%)
had early recurrence in the mechanical MVR group (p = 0.964). As shown
in Table 3, Cox univariate and multivariate regressions were used to
identify risk factors for AF recurrence. Univariate analysis showed that
blood glucose level was related to the recurrence of AF after catheter
ablation (p = 0.039). However, there was no significant risk factor
related to the endpoint event in multivariate analysis.
Eight patients had bleeding events with clinical symptoms in the
mechanical MVR group, mainly manifested as hematuria and nasal
hemorrhage, all of which used warfarin. The INR values were between 2.37
and 4.0 at occurrence of the bleeding events. No significant clinical
bleeding events were observed in the bioprosthetic MVR group (p =
0.368).