Abstract: Objectives. The present study aimed to evaluate maternal and fetal outcomes in patients who underwent percutaneous balloon mitral valvuloplasty (PBMV) during antenatal care. Methods. Analysis of 117 pregnant women who underwent PBMV for rheumatic mitral stenosis. Demographic, clinical, echocardiographic, hemodynamic, and Doppler examinations were performed. The pregnant women were stratified according to New York Heart Association classification. Apgar scores were recorded at 1, 5, and 10 minutes to assess the neonatal outcomes. Results. In our study cohort, 74.36% underwent PBMV during their second trimester, at gestational age of 22.49 ± 5.82. Term birth, mode of delivery, birth weight, and Apgar score at 5 minutes were significantly associated with pregnancy and neonatal outcomes. Mitral valve area, mitral valve gradient, and pulmonary artery systolic pressure were significantly improved (P<.001) after PBMV. Pulmonary edema, medical termination of pregnancy, hypothyroidism, hepatitis B infection, pneumonia, and postprocedural delivery, as well as postprocedure severe mitral regurgitation requiring surgery in 2 patients, were the few complications observed. Mean fluoroscopy time was 4 minutes, 50 seconds, with 100% success rate. No maternal mortality was observed. Conclusion. PBMV is a safe and effective intervention for mitral stenosis in pregnant women, with favorable maternal and short-term neonatal outcomes. PBMV offers excellent results in terms of symptomatic relief, hemodynamic improvement, and 100% success rate. Hence, it could be regarded as a preferred choice of intervention in managing symptomatic moderate to severe rheumatic mitral stenosis in pregnant women.
J INVASIVE CARDIOL 2020;32(11):427-432.
Key words: Apgar score, mitral valve area, mitral valve gradient, NYHA class, pulmonary artery systolic pressure, rheumatic mitral stenosis
The overall prevalence of rheumatic mitral stenosis in developed countries is estimated at 1%-2%, but in developing countries it is much more prevalent and accounts for 40%-50% of the cardiac disease seen in pregnancy.1,2 It is a predominant valvular disease among pregnant women in developing countries.3 Rheumatic fever is the main cause of mitral stenosis, whereas other causes include calcification of mitral valve and congenital heart disease.4,5 During mitral stenosis, the reduced mitral valve area (MVA) to <1 cm2 increases the pressure in the left atrium and results in loss of atrial kick, which eventually leads to decrease in the cardiac output and development of congestive cardiac failure. The common symptoms of mitral stenosis include palpitation, chest pain, thromboembolism, hepatomegaly, ascites, and edema.4 It is associated with adverse maternal outcomes, including arrhythmia, pulmonary edema, and thromboembolism, as well as adverse neonatal events, including intrauterine growth retardation, preterm delivery, low birth weight, and neonatal or fetal morbidity or mortality.6
Although there are several non-invasive tests, echocardiography is the standard imaging tool to assess patients with mitral stenosis.4 Medical therapy, percutaneous balloon mitral valvuloplasty (PBMV), and surgical therapy are the different options available for mitral stenosis.5 However, medical treatment is the first line of management in symptomatic patients. PBMV is a minimally invasive intervention that can be considered in symptomatic and asymptomatic patients with mitral stenosis. Surgical intervention/mitral valve replacement surgery is indicated in patients with moderate or severe mitral stenosis when PBMV is contraindicated due to mitral regurgitation (MR).7
Several studies8-11 have evaluated and put forward the clinical, echocardiographic, and hemodynamic outcomes of PBMV in the population of pregnant women with mitral stenosis. Considering the paucity of literature, we aimed to evaluate the maternal and fetal outcomes in patients who underwent PBMV during pregnancy at our tertiary-care center.
The study was conducted between January 2006 and December 2019, and included 117 pregnant women who underwent PBMV for rheumatic mitral stenosis at a tertiary-care center. The pregnant women were classified according to New York Heart Association (NYHA) functional class. Approval was obtained from the institutional ethical committee before commencement of the study. Informed consent was obtained from the patients prior to the initiation of the study. All patients underwent clinical exam (cardiac and obstetric), electrocardiography, and echocardiography before the intervention. Drug history, such as diuretics (furosemide), digoxin, and beta-blockers, was noted.
Inclusion criteria. All patients with severe mitral stenosis (MVA ≤1.5 cm2; with symptoms stage D or without symptoms stage C), or very severe mitral stenosis (MVA ≤1.0 cm2; with symptoms stage D or without symptoms stage C), who underwent PBMV with favorable valve morphology (Wilkins score ≤8) were included in the analysis.12
Exclusion criteria. Patients with moderate to severe MR at baseline, severe aortic or tricuspid valve disease that required surgery, recent thromboembolic stroke, presence of left atrial thrombi as confirmed by electrocardiography, and moderate to severe mitral stenosis with unsuitable valve morphology (Wilkins score >8) were excluded from the analysis.
Data collection. Demographics, including clinical characteristics of the pregnant women (maternal age, gestation weeks, gravidity, and number of fetuses) were recorded. The severity of mitral stenosis was assessed using two-dimensional and Doppler echocardiography, with special emphasis on mitral valve morphology, and echocardiographic mitral valve scores were assigned using criteria described by Wilkins et al.13 Two-dimensional planimetry was used to measure MVA. The MVA, mean diastolic mitral gradient, and pulmonary artery systolic pressure were assessed before and after PBMV.
Percutaneous balloon mitral valvuloplasty. The pregnant women, during antenatal care (ANC), underwent PBMV under local anesthesia using the Inoue balloon technique with transseptal, anterograde left-sided cardiac approach.14 Following transseptal puncture, an Inoue balloon was positioned in the mitral orifice. The balloon was inflated in a stepwise manner until the indentation in the balloon created by the stenotic valve was no longer visible.
Maternal outcome was recorded by assessing standard hemodynamics, including transmitral pressure gradient and pulmonary artery pressure, during the procedure. All hemodynamic measurements were obtained both before and immediately after PBMV. Heparin was given (100 IU/kg of body weight) after transseptal puncture. To minimize radiation exposure, left ventriculography was not performed. Fluoroscopy was used only when necessary. The patients’ abdomens and pelvises were shielded with a folded 5-mm lead shield throughout the procedure. Color Doppler technique was used to assess interatrial communication and severity of MR.15
Post PBMV, an MVA of ≥1.5 cm2 or an increase in MVA of >25% in comparison with baseline, and in the absence of severe MR, was considered to be a successful optimal outcome. Clinically, two-dimensional and Doppler echocardiographic studies were also performed after 24-48 hours in all patients.15 The course of further pregnancy was followed up regularly in the outpatient clinic after patient discharge.
When each patient was admitted for delivery, the mode of delivery was selected based on obstetrics indications, such as hydramnios/oligohydramnios, premature rupture of membranes >12 hours, placenta previa, and fetal distress.
Neonatal outcome was recorded by the pediatrician. Apgar scores16 were recorded at 1, 5, and 10 minutes to assess the neonatal outcomes (Table 1). Apgar scoring was repeated in cases with a low score. Apgar scores ≥7 were considered excellent condition, scores 4-6 as moderately depressed, and scores <3 as severely depressed.15
After birth, the infant and mother were followed in the cardiology outpatient clinic at 1 month, 3 months, 6 months, and 1 year. Each infant’s developmental milestones and physical and mental development were assessed and recorded during each follow-up visit.
Statistical analysis. R i3220.127.116.11 statistical software and Microsoft Excel were used to analyze the data. Continuous data were represented in the form of mean ± standard deviation and categorical variables were represented using the frequency table. Pre- and postprocedure data were compared using the Wilcoxon signed-rank test. Proportion/binomial test was used to study single proportions. A P-value <.05 was considered statistically significant.
Demographics, including clinical characteristics of the pregnant women, are provided in Table 2. A total of 117 pregnant women, mean age 24.87 ± 4.21 years, were considered for the study, with most patients (49.57%) in the age range of 20-25 years. Mean gestational age of the pregnant women was 22.49 ± 5.82 weeks. Most of the pregnancies were either gravida 1 (41.03%) or gravida 2 (35.04%), with only 1 twin pregnancy. Most of the pregnant women (63.25 %) were in NYHA functional class III. However, none of the patients had atrial fibrillation.
As shown in Table 3, most of the patients (74.36%) underwent PBMV during the second trimester at a mean gestational age of 22.49 ± 5.82 weeks; most of the patients (52 .14%) had a Wilkins score of 7, and 1 patient who had Wilkins score of 9 underwent PBMV as bailout procedure; she underwent medical termination of pregnancy (MTP). Antenatal trimester and Wilkins score had a significant association with PBMV. A significant improvement in MVA (P<.001) was found following PBMV, while mitral valve gradient and pulmonary artery systolic pressure were significantly reduced (P<.001). Eleven patients (9.40%) who previously underwent PBMV and presented with restenosis in this pregnancy were again symptomatic during this second pregnancy and therefore underwent PBMV. However, 106 patients (90.60%) in the study had not undergone previous PBMV.
As presented in Table 4, gestational age at the time of delivery was 37.22 ± 1.21 weeks. The majority (64.96%) were full-term pregnancies with healthy neonates; 2 neonates (1.70 %) were stillbirths (born without signs of life after 28 weeks of gestation) and 3 pregnancies (2.55 %) were medically terminated (1 during the first trimester, 1 at 20 weeks, and 1 at 22 weeks of gestation) for reasons unrelated to the present study. Vaginal and cesarean delivery rates of live births were 53.57% and 46.43%, respectively.
Among the 112 live births, 107 neonates (95.53%) were ≥2.5 kg and 5 neonates (4.47%) were ≤2.5 kg. Using Friedman’s test, we concluded that distribution of Apgar score was significantly different for at least 2 timepoints (P<.001). Using pairwise Wilcoxon sign-rank test with Bonferroni correction post hoc, we concluded that the distribution of Apgar score was significantly different at each timepoint (adjusted P<.001). Most of the neonates (70.94 %) had 5-minute Apgar scores of ≥7.
Mean gestational age of neonates with 5-minute Apgar score <7 (n = 29) was 37.35 ± 1.04 weeks. Of these 29 neonates, 13 were preterm births (<37 weeks) while 16 were full-term births (>37 weeks). Term birth, birth weight, and Apgar score at 5 minutes were significantly associated with pregnancy and neonatal outcomes.
As shown in Table 5, mean fluoroscopy time was observed to be 4 minutes, 50 seconds. Procedural success rate was 100%, and 2 patients developed postprocedure severe MR requiring surgery; both required mitral valve replacement. These patients were on medications, diuretics, and beta-blockers during the period between PBMV and surgery; they tolerated the postprocedural period well until delivery and underwent mitral valve replacement at 6 months post delivery. No pericardial effusion and maternal mortality were observed post intervention. Pulmonary edema (1.71%), MTP and stillbirth (4.27%), hypothyroidism (0.85%), hepatitis B infection (0.85%), pneumonia (1.71%), and postprocedural delivery (within 24 hours) (2.56%) were the few complications observed after PBMV.
Our study provides maternal and neonatal outcomes of PBMV for mitral stenosis among pregnant women in relation with fluoroscopy time and Apgar score. Studies have reported PBMV to be the most accepted intervention for pregnancy-associated rheumatic mitral stenosis, with precise assessment of clinical status and commissure morphology of the patients.3,10,17
Surgery/intervention during pregnancy is associated with several complications and significant maternal or fetal mortality, with hypothermia-induced uterine contractions and reduced placental flow.10 However, increase in MVA, as well as decreases in mitral valve gradient and pulmonary systolic blood pressure, will reduce the complications for the mother and fetus. Similarly, in our study, all hemodynamic parameters significantly improved after PBMV. Joshi et al18 also observed significant increase in mean MVA (1.49 ± 0.23 cm2 vs 1.60 ± 0.26 cm2; P<.05) and significant decrease in mean mitral gradient (19.13 mm Hg vs 8.9 mm Hg; P<.05) during follow-up immediately post procedure. Kumar et al2 reported significant increase in MVA from baseline value of 0.93 ± 0.17 cm2 to 1.75 ± 0.27 cm2 (P<.001) and significant decrease in pulmonary artery pressure from 43.05 ± 15.88 mm Hg to 22.31 ± 6.36 mm Hg (P<.001) after intervention.
Radiation exposure during fluoroscopy is hazardous to the unborn child.19 Hence, shielding the patient’s abdomen and pelvis may reduce the risk of radiation for both mother and fetus. The same was accomplished in our study to prevent adverse outcomes. Moreover, fetal abnormalities due to radiation exposure mostly occur before 20 weeks of gestation; thus, PBMV is usually performed during the second trimester.19 Therefore, in our study, the intervention was carried out during the second trimester at a mean gestational age of 22.48 ± 5.80 weeks. Only 1 pregnant woman underwent PBMV during the first trimester; she underwent MTP at a later date for reasons unrelated to the current study.
The literature has reported that PBMV is ineffective when the Wilkins score is >10 and it is associated with higher incidence of severe MR.20 In our study, all the pregnant women had Wilkins scores <10 and their results confirm that PBMV is effective to implement. One patient who had a Wilkins score of 9 underwent PBMV as bailout procedure; she later underwent MTP. It has been reported that Inoue balloon size of 26 mm is associated with lesser degree of MR and provides better results, and the same was observed in our study.
Although PBMV was 100% successful in the current study, patients with MR increased post PBMV. This might be due to a higher calcification score and a lower MVA, before PBMV.21 However, in some cases, it could not be predicted by clinical characteristics of the patient or by features of the valve/subvalvular apparatus.22 Therefore, there are no exact predictors to assess the development of MR post PBMV.
PBMV needs significant radiation time for fluoroscopy guidance for precise employment of the dilating balloon. As it is known that radiation exposure with fluoroscopy has adverse effects on fetuses, fluoroscopy time must be shortened. This can be achieved by using the Inoue technique rather than using a double-balloon intervention.23 Our study results were in accordance with this observation. The mean fluoroscopy time in our study was 4 minutes, 50 seconds. This time reflects the expertise of interventional cardiologists performing PBMV at a tertiary-care center. A recent case series from South India by Pillai et al24 found the mean fluoroscopy time to be 5.4 ± 5.8 minutes (range, 1.8-29 minutes), whereas Joshi et al18 reported the mean fluoroscopy time of their entire group to be 3.97 minutes.
Neonates with low Apgar score (0-3) at 5 minutes may suffer from adverse short-term and long-term neurodevelopmental abnormalities and neonatal mortality.25 With moderate Apgar scores (4-6), similar adverse outcomes will be evidenced, at lower magnitude.12,26 Conversely, in neonates with Apgar scores of ≥7 at 5 minutes, the adverse neonatal outcomes may progressively reduce.27 In our study, the mean Apgar score was 7.00 ± 0.75 at 5 minutes and 8.27 ± 0.48 at 10 minutes, which was similar to other reports.28,29 Thus, it can be concluded that children delivered at our institution had low risk of neonatal and infantile mortality.
Overall, our findings affirm that PBMV could be considered as relatively safe and effective for the management of mitral stenosis. PBMV offers excellent results in terms of symptomatic relief, hemodynamic improvement, and reduced fluoroscopy time, with a 100% success rate. Significant functional improvement goes hand in hand with hemodynamic improvement; furosemide and digoxin were discontinued in 80% and 70% of patients, respectively. There were no maternal deaths in our study. In contrast, mortality from surgical closed mitral commissurotomy was as high as 3%,30-32 while mortality from open commissurotomy reached 5%.33-36 Maternal and neonatal outcomes were observed immediately after the study (short term). Hence, long-term maternal and fetal outcome studies with large sample sizes must be conducted to reach a definitive conclusion.
Study limitations. This is a single-center study and it is not possible to elaborate on the results by comparison with a control group (either medically managed patients or healthy pregnant women).
PBMV is a safe, effective, and less-invasive intervention for rheumatic mitral stenosis in pregnant women with favorable maternal and short-term neonatal outcomes. Hence, with no contraindications, this could be recommended as a preferred choice of intervention in managing symptomatic moderate to severe rheumatic mitral stenosis in pregnant women.
From the Department of Cardiology, Jawaharlal Nehru Medical College, Belagavi, Dr Prabhakar Kore Hospital and Medical Research Center, Belagavi, Karnataka, India.
Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. The authors report no conflicts of interest regarding the content herein.
Manuscript accepted March 23, 2020.
Address for correspondence: Dr Vaibhav Bansidhar Patil, Assistant Professor, Department of Cardiology, Jawaharlal Nehru Medical College, Dr Prabhakar Kore Hospital and Medical Research Center, Belagavi, Karnataka, 590010, India. Email: firstname.lastname@example.org
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