balloon mitral valvotomy in pregnancy: maternal and fetal outcomes

Balloon Mitral Valvotomy in Pregnancy:Maternal and Fetal Outcomes

Anup Gupta, MD, Yash Y Lokhandwala, MD, Purnima R Satoskar, MD, and Vinita S Salvi, MD

Background: Rheumatic mitral valve stenosis contrib-utes to significant morbidity in pregnancy. Surgicalcommissurotomy has been performed during pregnancyin patients with severe mitral stenosis for several de-cades, but the efficacy and safety of percutaneous bal-loon mitral valvotomy (BMV) in this subset has notbeen clearly defined.

Study Design: In 1996 and 1997, 40 pregnant womenaged 24 6 5 years underwent BMV at 21 6 11 weeks ofpregnancy. Special shielding was used during BMV tolimit radiation to the fetus, except in those who were toundergo medical termination of pregnancy subse-quently. A detailed echocardiographic evaluation wasperformed before and after BMV. After the BMV, the 29patients in whom pregnancy was continued were as-sessed every 2 weeks for symptoms and fetal growth.

Results: The BMV procedure was successful in 39 pa-tients with an increase in mitral valve area from0.8 6 0.2 cm2 to 1.7 6 0.2 cm2 (p < 0.001) andmarked symptomatic relief. Fluoroscopy time was7.8 6 1.9 minutes. Eleven patients whose BMV wasperformed before 20 weeks of pregnancy, subsequentlyunderwent medical termination of pregnancy unevent-fully. Eighteen patients had a normal delivery, three un-derwent cesarean section for fetal distress, one had apreterm delivery, and there was one stillbirth. Four pa-tients are continuing pregnancy and two are lost to fol-lowup. Fullterm delivery data were available in 23 ba-bies, whose birth weights were 2.32 6 0.5 kg. None ofthese babies needed any special care and were healthy atdischarge.

Conclusions: During pregnancy, BMV by the Inouetechnique is feasible, safe, and effective. There is markedsymptomatic relief, along with excellent maternal andfetal outcomes. (J Am Coll Surg 1998;187:409–415.© 1998 by the American College of Surgeons)

Rheumatic mitral valve disease is the most commonform of organic heart disease encountered in Indiaduring pregnancy. Mitral stenosis (MS) leads to sig-nificant maternal and fetal mortality and morbidi-ty.1,2 The hemodynamic stress of pregnancy, alongwith thromboembolism and atrial fibrillation mayprecipitate acute pulmonary edema and cardiogenicshock in patients with mitral stenosis. Surgical mitralvalvotomy has been performed in many critically illpregnant women.3 Closed or open surgical commis-urotomy, however, carries a significant morbidity.3-9

Balloon mitral valvotomy results in excellent im-mediate hemodynamic improvement in selected pa-tients with mitral stenosis.10-12 Use of this techniquein pregnant patients with mitral stenosis has beenrestricted by risk of radiation exposure to the fetus.13

The purpose of this study was to prospectively exam-ine fetal and maternal outcomes following balloonmitral valvotomy.

METHODSFrom January 1996 to December 1997, 40 pregnantwomen aged 24 6 5 years underwent percutaneousballoon valvotomy for severe rheumatic mitral steno-sis. Clinical features of the patients are summarizedin Table 1. Nine patients had New York Heart Asso-ciation class 4 dyspnea, 23 had class 3 symptoms, andeight had class 2 symptoms. All patients except onewere in sinus rhythm. In 22 patients, the diagnosis ofMS had been made before the current pregnancy. Inthe 18 patients in whom MS had never been diag-nosed, seven were multigravida. Twenty patientswere on regular penicillin prophylaxis, all 40 weretaking diuretics, 21 were on beta-blockers, and sixwere taking digoxin. The time of intervention was21 6 11 weeks (range, 6 weeks to 36 weeks) of am-enorrhea. Eleven patients were primigravida. The se-verity of MS and the morphology of the mitral valve(MV) was assessed before valvotomy using two di-mensional (Fig. 1A) and color Doppler echocardiog-

Received May 4, 1998; Accepted June 24, 1998.From the Departments of Cardiology (Gupta, Lokhandwala) and Obstetrics(Satoskar, Salvi), King Edward Memorial Hospital, Mumbai, India.Correspondence address: Yash Lokhandwala, Department of Cardiology, KEMHospital, Parel, Mumbai-400012, India.

409© 1998 by the American College of Surgeons ISSN 1072-7515/98/$19.00Published by Elsevier Science Inc. PII S1072-7515(98)00201-4

raphy. The echocardiographic MV score was6.6 6 0.8; a higher score, especially more than 8,denoted more deformed valves.14 No patient had ev-idence of left atrial thrombus at echocardiography.The MV area was 0.8 6 0.2 cm2 and there were sig-nificant gradients recorded across the MV, as out-lined in Table 2.

Balloon mitral valvotomy procedureTo limit fetal radiation exposure during the cath-

eterization procedure, patients were wrapped cir-cumferentially in a lead apron covering the abdomenfrom the subcostal margin to the symphysis pubis,except in those who were to undergo elective medicaltermination of pregnancy (MTP) after the BMVprocedure. Cardiac catheterization was performedunder local anesthesia via the femoral vessels. A 6Fpigtail catheter was passed into the ascending aorta.Except in patients with severe pulmonary hyperten-sion, a pulmonary arterial catheter was not inserted,to limit the radiation exposure.

Balloon mitral valvotomy was performed usingthe well-established Inoue balloon technique.15

Transseptal catheterization of the left atrium was per-formed using the Brockenbrough technique, afterwhich 100 U/kg of intravenous heparin was admin-istered. The transmitral gradient was recorded (Fig.2). A spring guide wire was placed inside in the leftatrium, over which the Inoue balloon catheter waspassed and maneuvered across the mitral valve. Theballoon was inflated (Fig. 3) up to a predetermineddiameter (height in cm/10 1 10) to achieve splittingopen of the fused MV commissures. Measurements

of the transmitral gradient were repeated after theinflation. Two-dimensional and color Doppler echo-cardiography were repeated 24 hours after balloonmitral valvotomy. The patients were transferred tothe obstetric ward after 24 hours.

Obstetric evaluationBefore the procedure, an ultrasound examination

was performed to document gestation age, placentallocalization, and absence of congenital anomalies.After BMV, medical termination of pregnancy wasperformed in patients who had not completed 20weeks of pregnancy. The remaining patients werekept under observation in the obstetric ward for 10to 14 days. Subsequently, they were advised antenatalfollowup every 2 weeks. The patients were readmit-ted at 35 to 36 weeks of gestation.

Fetal growth was monitored by maternal weightgain, serial fundal height, clinical palpation, and ul-trasonography. Fetal well-being was monitored byserial fetal heart auscultation, daily fetal kick countchart, bi-weekly nonstress test (electronic fetal heartrate monitoring), and biophysical profile.

Spontaneous labor was awaited in all patients un-less there was an obstetric indication for induction oflabor. Cervical prostaglandin gel and oxytocin dripwas used in patients requiring induction. Cesareansection was performed under general anesthesia.

Definitions and statistical analysisSuccessful BMV was defined as a 50% or more

increase in MV area without any major complica-tions (death and severe mitral regurgitation). Lowbirth weight was defined as less than 2.5 kg, in accor-dance with standard criteria. Continuous variablesare expressed as mean 6 S.D. The significance of thedifference between continuous variables was assessedby the Student’s t-test.

RESULTS

Balloon mitral valvotomyThe BMV procedure was successful in 39 of 40

patients. Symptomatic status improved markedly asshown in Table 1. There was an increase in the MVarea from 0.8 6 0.2 to 1.7 6 0.15 cm2 (p , 0.001)and a significant decrease in the transmitral pressuregradients, as shown in Table 2. The left atrial pressurefell from 32 6 9 to 16 6 10 mmHg (p , 0.05).Echocardiography revealed that both MV commis-sures were split (Figure 1B) in 22 patients, and only 1MV commissure was split in 17 patients. Neither

Table 1. Clinical Characteristics

CharacteristicBefore balloon

mitral valvotomyAfter balloon

mitral valvotomy

GravidaPrimi 11 —Multi 29 —

Weight (kg), 50 26 —50–60 14 —

Height (cm), 140 5 —140–150 23 —. 150 12 —

Class of dyspneaGrade 2 8 6Grade 3 23 1Grade 4 9 1

Hemoglobin (gm%), 9 14 —9–11 20 —. 11 6 —

410 Gupta et al Balloon Mitral Valvotomy in Pregnancy J Am Coll Surg

commissure was split in the solitary patient who de-veloped severe mitral regurgitation from a tear of theanterior mitral leaflet and had to undergo mitralvalve replacement. The procedure time was 35 6 7minutes, and the fluoroscopy time was 7.8 6 1.9minutes. The balloon diameter used was 24 61.2 mm (range, 22 to 28 mm).

Mitral regurgitation was seen after BMV in sixpatients, in five of whom it was insignificant(# grade 1/3). In the solitary patient who developed

severe mitral regurgitation after BMV, urgent MVreplacement was performed successfully and she sub-sequently underwent MTP uneventfully. Two pa-tients developed lower limb venous thrombosis afterBMV, which resolved with intravenous heparin ther-apy over the next few days. One patient with a post-BMV MV area of 1.6 cm2, died suddenly 3 dayslater, probably from a massive pulmonary thrombo-embolism. A postmortem examination was notperformed.

Figure 1. Echocardiographic parasternal short axis view showing a stenotic mitral valve (MV) with fused commissures(A). After BMV, both medial and lateral commissures are open (arrows) (B).

411Vol. 187, No. 4, October 1998 Gupta et al Balloon Mitral Valvotomy in Pregnancy

Maternal outcomesOf the 11 women who underwent BMV before

20 weeks of pregnancy, nine underwent MTP bysuction and evacuation performed under sedationand local anesthesia. One patient aborted spontane-ously after the BMV before MTP could be done, andone patient underwent MTP by instillation ofethacridine lactate.

Of the 29 women who underwent BMV after 20weeks of pregnancy, 18 subsequently had fulltermvaginal deliveries, including outlet forceps applica-tion in three patients. Three patients underwent ce-sarean section for fetal distress. One patient deliveredat 36 weeks of gestation. One patient who did notfollowup in the ninth month for antenatal care de-spite reduced fetal movement for a week, directlypresented with an intrauterine fetal death and deliv-ered a macerated baby. Two patients were lost to fol-lowup, and 4 patients are awaiting delivery. None ofthe patients who delivered had any peripartum car-diac complication such as pulmonary edema, conges-tive heart failure, or bacterial endocarditis. Motherswere discharged 10 to 14 days after delivery.

Fetal outcomesFullterm delivery data were available in 23 ba-

bies, as outlined above. Neonatal birth weights were2.32 6 0.5 kgs. The birth weight was 2.26 6 0.4 kgand 2.35 6 0.5 when BMV was performed in thesecond and third trimesters, respectively (p 5 NS).Ten babies (43%) had low birth weight (three of sixhad second trimester BMV and seven of 17 had thirdtrimester BMV, p 5 NS). None of these babies

needed any special supportive measures and were dis-charged in healthy condition. The preterm babyweighed 1.7 kg and did well thereafter.

DISCUSSIONMitral stenosis produces symptoms from pulmonarycongestion, left atrial stretch leading to atrial fibrilla-tion, and low cardiac output. The additional hemo-dynamic stress of pregnancy leads to worsening ofpulmonary congestion. Anemia and infection mayalso lead to precipitation of pulmonary edema in thissetting. Ideally, if severe MS (MV area , 1 cm2) isdiagnosed before pregnancy, it should be relieved byBMV or surgery before conception. Otherwise, thesepatients tolerate pregnancy poorly, with high mater-nal and fetal morbidity and mortality,1,2 and the fre-quent need for emergent intervention during preg-nancy. Even patients with moderate MS (MV area1–1.5 cm2) may develop severe dyspnea during thesecond trimester because of increased blood volumeand cardiac output. In India, because of illiteracy,poverty, and an inadequate health care structure, pa-tients with severe MS are often seen in a pregnantstate, as apparent from the current study.

Surgical commissurotomy of the mitral valveduring pregnancy was first performed in 1952.16,17

Since then, both open (with cardiopulmonary by-pass) and closed surgical mitral commisurotomieshave been performed for relief of mitral stenosis inpregnant women. Use of cardiopulmonary bypassand hypothermia has been associated with a 15% to33% incidence of fetal mortality.5 In addition, thelongterm effects of cardiopulmonary bypass on thefetus are not known. Closed mitral commisurotomycarries a lower risk of fetal demise, although a 5% to15% of fetal abortion after surgery has been associ-ated with this technique as well.5 Moreover, if per-formed close to term, the pain and inflammation ofthe intercostal incision often prevents adequate bear-ing down during labor.

Balloon mitral valvotomy is a relatively safe pro-cedure that has become widely prevalent over the lastdecade. In our center, over 2500 BMVs have beenperformed with a 1% incidence of major complica-tions. For patients with MS from restenosis after pre-vious surgical commisurotomy, BMV is also feasibleand safe.18 With increasing experience and the intro-duction of the Inoue balloon catheter, fluoroscopytime for BMV has significantly shortened.19 Hence,over the last few years, a few large volume centershave offered BMV for pregnant women with severe

Table 2. Mitral Valve Anatomy and HemodynamicsBefore and after Balloon Mitral Valvotomy

Beforeballoon mitral

valvotomy

Afterballoon mitral

valvotomy

Mitral valve area (cm2) 0.8 6 0.2 1.7 6 0.15Transmitral valve gradient

Peak 42 6 7 14 6 5Mean 26 6 7 9 6 5

Mean left atrial pressure 32 6 9 16 6 10Peak pulmonary arterial

pressure 66 6 24 47 6 16Mitral valve commissures

MedialFused 40 8Open 32

LateralFused 40 11Open 29

Both commissures were split after BMV in 22 patients.


mitral stenosis. While BMV during pregnancy car-ries a very low maternal and fetal mortality, as seen inour study, the longterm effects of radiation to thefetus need to be addressed. However animal and hu-man data20-22 suggest that no increase in the incidenceof congenital malformation or abortion occurs withfetal radiation exposure , 5 rads, and a maximumfluoroscopy time of 16 minutes.21,22 In the cur-rent study, the mean fluoroscopy time was7.8 6 1.9 minutes, which was well within this limit.Only in one patient did the fluoroscopy time exceed

16 minutes, but she subsequently underwent MTPanyway. With proper precautions, the radiation ex-posure to the fetus can be kept minimal and shouldnot have deleterious consequence in the longterm.Patients who are hemodynamically stable and wantto continue their pregnancy should ideally undergothe procedure after the second trimester of pregnancyto minimize the risk of fetal damage after radiationexposure.

As seen in our study, adequate MV dilationcould be obtained in 39 of 40 patients. The MV

Figure 2. Pressure tracing before balloon mitral valvotomy. (A) There is a large transmitral gradient, indicated by thearrowheads. LA, left atrium, LV, left ventricle. Pressure tracing after balloon mitral valvotomy. (B) The pressures in theleft atrium (LA) and left ventricle (LV) in diastole have equalized.


area increased from 0.8 6 0.2 cm2 to1.7 6 0.15 cm2. This was accompanied by a markedfall in the mean transmitral gradient from26 6 7 mmHg to 9 6 5 mmHg. These postBMVindices signify good hemodynamic status, and car-diac output can now be expected to increase ade-

quately during effort such as straining during labor.The fall in the left atrial pressures from32 6 9 mmHg to 16 6 10 mmHg seen in our studyrelieved the pulmonary venous congestion and pre-vented the development of pulmonary edema.

In pregnant women, some technical problemsmay be encountered during the BMV procedure.The hypercoagulable state in pregnancy necessitatesa quick transseptal puncture, after which heparin canbe administered. In the present study two patientsdeveloped venous thrombosis in the lower limbs.Since then, it has been our practice to continue subu-taneous heparin, twice daily for 7 days after the BMVprocedure. The gravid uterus may compress and dis-tort the inferior vena cava, making passage of cathe-ters difficult. In view of the above, we dispensed withinsertion of a catheter into the pulmonary artery inpatients without severe pulmonary arterial hyperten-sion, as assessed by the color Doppler examination.The elevated diaphragm near term may alter theusual lie of the interatrial septum, making it morehorizontal. This is crucial to assess before performingthe transseptal puncture. The high cardiac outputstate of pregnancy produces higher gradients acrossthe MV, which should be kept in mind while assess-ing the result of BMV during the procedure.

Severe mitral regurgitation is known to occur af-ter BMV in 2% of patients,23 from rupture of majorchordae or tears of the MV leaflets. This complica-tion may also be seen in 3% of patients after closedsurgical commisurotomy.23 Severe mitral regurgita-tion is more likely to result when BMV is performedfor calcific, severely deformed valves that are desig-nated to have a high MV score (more than 8) onechocardiography.24 This complication is often un-predictable and may also occur in valves that are lessdeformed. The MV score was 6 in the solitary patientwho developed severe mitral regurgitation in ourstudy. Mild mitral regurgitation, which was seen infour of our patients, is benign and is usually fromexcessive commissural splitting or a minor chordalrupture.

This study found a high incidence (43%) of lowbirth weight. This, at first sight, is surprising, becauseafter BMV the cardiac output and uteroplacentalflow would be expected to improve. Along with im-proved maternal health after BMV, these factors areexpected to promote fetal health. There is however, a45% incidence of low birth weight in our hospital inchildren of women without heart disease. This highincidence is multifactorial; ours is a free public hos-pital, with the majority of patients belonging to the

Figure 3. (A) The Inoue balloon catheter is being inflated across themitral valve. The “waist” (arrow) is the site of the stenosis. (B) Fullyinflated balloon, with disappearance of the waist.


lower socioeconomic strata of society. Chronic un-dernourishment, frequent pregnancies, and anemiaare common in these patients. Viewed in this light,the 43% incidence of low birth weight after BMVseems reasonable. To really assess the impact of BMVin improving fetal growth, one would have to com-pare this group with a concurrently untreated groupof pregnant women with severe MS, which is notfeasible. It was heartening that all babies did wellafter birth.

This study illustrates that BMV by the Inoueballoon technique is feasible, largely safe, and effec-tive when performed on pregnant women. There ismarked symptomatic relief following the procedure,accompanied by significant improvement in hemo-dynamic parameters. The maternal and fetal out-comes are excellent when proper precautions aretaken.

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balloon mitral valvotomy in pregnancy: maternal and fetal outcomes

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