Patients who were diagnosed with PSAR and $\ge$mild functional mitral regurgitation (FMR), and underwent TAVR (Venus-A valve, Hangzhou QiMing Medical Equipment Co., Ltd.) at the Zhongshan Hospital Affiliated with Fudan University from June 2020 to June 2024 were enrolled. All patients were considered unsuitable for surgical valve replacement after a comprehensive evaluation. In addition, all patients had a follow-up of $\ge$1 month and underwent cardiac ultrasound examinations. The exclusion criteria were as follows: (1) patients with failed surgical bioprosthetic valves; (2) peak aortic valve pressure gradient measured by pre-TAVR echocardiography greater than 20 mmHg; (3) primary mitral regurgitation; (4) concomitant hypertrophic obstructive cardiomyopathy; and (5) concomitant left ventricular thrombus or infective endocarditis. This study was approved by the Ethics Committee of the the Zhongshan Hospital Affiliated with Fudan University (number: B2025-077), and all patients were informed and signed a consent form.

Based on whether FMR improved post-TAVR, patients were divided into the MR-improved group and the MR-nonimproved group according to echocardiography. Clinical information on the patients was collected from medical records and the catheterization laboratory information system for retrospective analysis. The baseline information of patients, such as hypertension, diabetes, pulmonary arterial hypertension, atrial fibrillation, heart failure, and renal insufficiency before surgery, was documented. Patients underwent multidetector computed tomography (CT) and echocardiography examinations, and postoperative follow-up echocardiography was performed. Parameters such as left ventricular ejection fraction (LVEF), left atrial and left ventricular dimensions, degree of aortic valve regurgitation, and mean transvalvular pressure of the aortic valve were recorded. MR grading was established according to the European Society of Echocardiography diagnostic criteria [5]. It was quantified as none or trace, mild, mild-moderate, moderate, moderate-severe, or severe. Grading of AR severity was based on the valve regurgitant jet area obtained from echocardiography: none, trace, mild, moderate, and severe. FMR, which was improved post-TAVR, was defined as $\ge$1 degree reduction in MR degree by echocardiography at one month postoperatively.

All patients underwent TAVR via intravenous anesthesia by the structural heart disease surgery team in the Department of Cardiology, Zhongshan Hospital. When using Venus, an auto-expandible device to treat AR, the length from the base of the left coronary sinus to the midpoint of the anterior mitral leaflet should be greater than 25 mm; otherwise, the mitral valve function would be affected. Patients had a follow-up visit at the outpatient department 30 days postoperatively, at which time transthoracic echocardiography (TTE) and electrocardiography (ECG) examinations were performed and perioperative endpoint events recorded. The definition of clinical outcomes followed the Valve Academic Research Consortium-3 (VARC-3) criteria [12]. The primary endpoints included all-cause death and cardiovascular death. The secondary endpoints included TAVR-related complications, such as myocardial infarction, major bleeding events, major vascular complications, acute kidney injury, stroke, endocarditis, new-onset atrial fibrillation, implantation of a new pacemaker, coronary artery obstruction, moderate or greater paravalvular leak, and rehospitalization.

Statistical analysis of the data was conducted using Stata 15.1 software (StataCorp LLC, College Station, TX, USA). The mean $\pm$ standard deviation (s) was used to represent normally distributed continuous variables, and proportions (%) were used for categorical variables. The comparison between the two groups was analyzed by an independent sample t-test and $\chi$² test. If the frequency was 5, Fisher’s exact probability method was used for comparisons between groups. A two-sided test was used. Univariable and multivariable logistic regression analyses were performed to evaluate the degree of correlation between MR improvement and clinical indicators. The quantitative data with a normal distribution among multiple groups were compared by analysis of variance, the quantitative data with a skewed distribution among multiple groups were compared by the Kruskal‒Wallis H test, the qualitative data between multiple groups were compared by the $\chi$² test, and the test level ($\alpha$) was 0.05. Baseline characteristics showing significant differences between the two groups were first analyzed using univariate regression. Those with a p-value 0.05 were then included in the multivariate regression model. In addition, several clinical factors with a strong correlation to mitral regurgitation (age, male, body mass index [BMI], left atrial diameter [LAD], and atrial fibrillation [AF]) were also incorporated into the univariate and multivariate regression analysis. Continuous variables in the model (age, BMI, LAD, left ventricle end-systolic dimension [LVEDs], and LVEF) were retained as continuous variables in the regression model.

A total of 111 patients were enrolled, including 52 with persistent MR, with a mean age of 72.47 $\pm$ 7.12 years; 69 were males, and 42 were females (Table 1).

Compared to patients without FMR improvement, significantly less patients in the FMR-improved group were diagnosed with renal insufficiency (0% vs. 10%, p = 0.015), left bundle branch block (0% vs. 8%, p = 0.030), and more were diagnosed with hypertension (80% vs. 56%, p = 0.007), and right bundle branch block (10% vs. 0%, p = 0.018). There were no significant differences in age, male sex, height, weight, body mass index, smoking, hyperlipidemia, diabetes mellitus, atrial fibrillation, previous percutaneous coronary intervention (PCI), permanent pacemaker (PPM), peripheral vascular disease, symptoms, atrioventricular block, New York Heart Association (NYHA) functional class III or IV, hemoglobin, serum creatinine, N-terminal pro-B-type natriuretic peptide, alanine aminotransferase (ALT), or Society of Thoracic Surgeons (STS) risk score between the two groups (Table 1). The TTE examination showed that patients in the MR-improved group had a lower ejection fraction (49.45 $\pm$ 8.05 vs. 60.53 $\pm$ 7.75, p 0.001) and a larger LVEDs (41.91 $\pm$ 8.19 vs. 38.10 $\pm$ 6.96, p = 0.010). A greater proportion of patients in the MR-improved group had moderate or greater tricuspid regurgitation (TR) (22% vs. 5%, p = 0.014). No significant differences were found between these two groups in left atrial end dimension (LAED), left ventricle end-diastolic dimension (LVEDd), interventricular septal thickness (IVS), left ventricular outflow tract diameter (LVOTD), aortic valve peak velocity, mean valve gradient, effective orifice area, severe AR, moderate or greater TR, pulmonary artery systolic pressure (PASP), aortic annulus area, aortic annulus perimeter, or aortic annulus long axis diameter (Table 2).

The overall decrease in MR severity after TAVR was observed only in the MR-improvement group (preoperative vs. postoperative day 1 vs. postoperative month 1, p = 0.001), whereas postoperative AR severity significantly improved in both groups (preoperative vs. postoperative day 1 vs. postoperative month 1, p 0.001) (Fig. 1A–D). Fig. 2 shows the AR and MR findings before TAVR and at 1-month post-TAVR on echocardiography.

Fig. 1.

Changes of AR and MR before and after TAVR were assessed in both groups. (A) MR degree at baseline, 1-day post-TAVR, and 1-month post-TAVR in MR improved group. (B) MR degree at baseline, 1-day post-TAVR, and 1-month post-TAVR in MR non-improved group. (C) AR degree at baseline, 1-day post-TAVR, and 1-month post-TAVR in MR improved group. (D) AR degree at baseline, 1-day post-TAVR, and 1-month post-TAVR in MR non-improved group. MR, mitral regurgitation; AR, aortic regurgitation; TAVR, transcatheter aortic valve replacement.

Fig. 2.

The echocardiography examination showing the AR and MR before TAVR and 1-month post-TAVR. (A) The echocardiography examination showed severe MR before TAVR. (B) The echocardiography examination showed trace MR one-month post-TAVR. AR, aortic regurgitation; MR, mitral regurgitation; TAVR, transcatheter aortic valve replacement.

There was no significant difference in primary and secondary endpoints in patients with or without improvement of MR who underwent TAVR in the hospital and 1 month after the operation. All-cause death or cardiac death did not occur in the two groups. During hospitalization, bleeding events, major vascular complications, stroke, new-onset atrial fibrillation, new-onset left bundle branch block, new-onset atrioventricular block, permanent pacemaker implants and moderate-to-severe paravalvular leaks were 0%, 2%, 0%, 11%, 19%, 18%, 19%, and 11% in the MR improved group and 4%, 2%, 4%, 13%, 12%, 23%, 13%, and 13% in the MR nonimproved group, respectively. In the 1-month follow-up, 2% stroke, 2% new-onset atrioventricular block, 2% new permanent pacemaker implantation, 8% paravalvular leak (PVL), and 4% rehospitalization were observed in the MR-improved group. The non-improved MR group had 4% bleeding events, 2% stroke, 4% new left bundle block, 2% new-onset atrioventricular block, 2% permanent pacemaker, 7% moderate or greater paravalvular leaks, and 9% rehospitalization (Table 3).

The results of univariable and multivariable logistic regression analyses for the FMR improvement are shown in Table 4. Age, male, BMI, LAD, and AF were incorporated into the univariable and multivariable logistic regression analysis. Among the variables, MR degree, LVEDs, hypertension, and LVEF were associated with FMR improvement (all p 0.05). In the multivariable analysis, higher MR degree, lower LVEF, and suffering from hypertension were independently associated with FMR improvement in patients post-TAVR (Table 4).

This study also has some limitations. First, the lack of CT parameters for FMR restricted our further investigation on tenting height, valve leaflet motion, and mitral calcification, which should be taken into consideration in future studies. Second, the number of patients in our study is small, and more patients should be enrolled in future research. Third, further screening and study of the population with the presence of $\ge$ moderate MR after TAVR should be followed. Finally, the follow-up time was limited, and the results should be further confirmed by future studies with larger sample sizes and prolonged follow-up.