Percutaneous balloon mitral valvuloplasty during a twin gestation. (Case Histories).

ABSTRACT: Although percutaneous balloon mitral valvuloplasty is known to be a safe and effective procedure during a singleton pregnancy, its use during a twin gestation is limited to a single report with a poor obstetric outcome. In the case we are reporting, a 29-year-old nulliparous patient with a twin gestation was seen at 24 weeks' gestation with congestive heart failure caused by previously undiagnosed mitral stenosis. She had successful percutaneous balloon mitral valvuloplasty, and two healthy infants were subsequently delivered at 36 weeks' gestation.

SUCCESS with percutaneous balloon mitral valvuloplasty for the management of severe mitral stenosis during pregnancy has been amply demonstrated for singleton pregnancies. However, search of the literature yielded only one report in which a woman with a twin gestation had balloon mitral valvuloplasty, resulting in improved maternal condition, but with development of fetal growth restriction, preterm delivery, and neonatal death of both twins. (1) The following is the first report of a successful pregnancy outcome after percutaneous balloon mitral valvuloplasty for severe mitral stenosis complicating a twin gestation.

CASE REPORT

A 29-year-old primigravida with a 24-week twin gestation had a near syncopal episode while at work. The patient is a nurse, and at the end of her shift she complained of feeling light-headed and dizzy. Her blood pressure was found to be 60/palpable. She was taken immediately to the emergency room, where she received an intravenous fluid bolus of approximately 1,500 mL. Hydration led to improved blood pressure, but shortness of breath developed, and the patient was found to have pulmonary edema.

The patient was transferred to a hospital with obstetric facilities, where she was admitted to the intensive care unit. An echocardiogram showed moderate mitral stenosis, with an estimated mitral valve surface area of 1.4 [cm.sup.2] (normal, 4 to 6 [cm.sup.2]). Mild atrial enlargement and mild aortic regurgitation were also noted. Telemetry revealed sinus tachycardia; there were no episodes of atrial fibrillation, flutter, or supraventricular tachycardia. The patient was stabilized with furosemide, metoprolol, and digoxin. Fetal heart rate monitoring of both fetuses remained reassuring during this time.

The patient's medical history was unremarkable. She had no record of rheumatic fever; her prepregnancy exercise tolerance was good, and she had no history of palpitations, chest pain, or shortness of breath. The course of her pregnancy, a spontaneous conception of diamnioticdichorionic twins, had also been unremarkable until this point.

The patient was discharged home on day 8. She continued to take both metoprolol and digoxin, and was placed on bedrest. She had close outpatient follow-up by her obstetrician, perinatologist, and cardiologist. From a cardiovascular standpoint, she remained stable with a sedentary level of activity, and her condition was considered a functional New York Heart Association class III. Fetal growth, measured by ultrasonography, remained appropriate for gestational age and concordant for both twins. At 30 weeks' gestation, repeat echocardiogram showed further deterioration. The mitral valve surface area measured 1.2 [cm.sup.2], and was associated with moderate pulmonary hypertension. The decision was made by her cardiologist to proceed with valvuloplasty.

Percutaneous balloon mitral valvuloplasty was done without complication. Using the transseptal technique, a balloon was inflated sequentially at 22.0 to 26.5 mm diameter in the mitral orifice. A postprocedure echocardiogram showed the mitral valve surface area improved to 2.2 [cm.sup.2]. The Table shows hemoclynamic measurements before and after valvuloplasty. The patient did receive prophylactic tocolysis with magnesium sulfate perioperatively. She remained asymptomatic for the remainder of her pregnancy.

Spontaneous labor commenced at 36 weeks' gestation. The patient received antibiotics for prophylaxis against subacute bacterial endocarditis. Twin A was delivered vaginally. He weighed 5 lb 4 oz, and had Apgar scores of 9 at 1 minute and 9 at 5 minutes. Because of a prolonged bradycardia, twin B was delivered by low transverse cesarean section. He weighed 5 lb 9 oz, and had Apgar scores of 6 at 1 minute and S at 5 minutes. The patient's postpartum course was unremarkable, and she was discharged from the hospital on postoperative day 3.

DISCUSSION

The normal hemodynamic changes associated with pregnancy are usually well tolerated. This case report points Out that in the presence of mitral stenosis, even a previously asymptomatic patient can become seriously compromised by these anticipated hemodynamic changes. The narrowed mitral valve surface area causes a decrease in cardiac output and an increase in pulmonary artery pressure. As pregnancy progresses, the intravascular volume normally increases. The effort required to pump increasingly greater volumes across a fixed narrowing potentiates cardiovascular decompensation.

Conservative medical treatment of symptomatic mitral stenosis includes bed rest, sodium restriction, and medications. Beta-blockers are used to slow the heart rate and thereby improve ventricular filling time and cardiac output. Digoxin can be used to slow the heart rate and as prophylaxis for tachyarrhythmias. Diuretics are administered cautiously to treat volume overload.

Percutaneous balloon valvuloplasty of the mitral valve should be considered when medical management is unsuccessful. Numerous case reports show the safety and efficacy of the procedure during pregnancy. (1-7) Because of the paucity of data regarding this procedure during a multiple gestation pregnancy, we were hesitant about our patient's procedure. The one previously reported patient with twins did improve from a New York Heart Association class TV to class I after the procedure. This improvement in maternal condition did not improve the pregnancy outcome, however. She was delivered prematurely (32 weeks) of infants weighing 1.0 and 1.5 kg who both died of respiratory failure at 48 hours. (1)

With the worsening of our patient's cardiovascular status despite conservative treatment, we considered the balloon valvuloplasty to be the best option for maternal well-being. Magnesium sulfate was used as prophylaxis against contractions during the procedure. The cardiologist encountered some difficulty in passing catheters through the venous system, which appeared to be due to compression of the vessels by the gravid uterus. By shifting her weight from side to side, the catheters were able to pass unobstructed. Otherwise, the procedure was unremarkable. This case suggests that balloon mitral valvuloplasty can be as safe and effective during a twin gestation as in a singleton pregnancy, with successful outcomes for mother and infants.

TABLE

Hemodynamic Measurements Before and After Mitral Valvuloplasty

                                                       Mitral Valve
                      Mitral Gradient  Cardiac Output  Surface Area
                          (mm Hg)         (L/min)         (cm2)

Before valvuloplasty        9.2             4.4            1.2
After valvuloplasty         2.5             4.8            2.2

                      Pulmonary Catheter  Pulmonary Artery
                        Wedge Pressure    Systolic Pressure
                           (mm Hg)             (mm Hg)

Before valvuloplasty          20                 50
After valvuloplasty           10                 39

References

(1.) Esteves CA, Ramos AI, Braga SL, et al: Effectiveness of percutaneous balloon mitral valvotomy during pregnancy. Am J Cardiol 1991; 68:930-934

(2.) Ben Farhat M, Maatouk F, Betbout F, et al: Percutaneous balloon mitral valvuloplasty in eight pregnant women with severe mitral stenosis. Eur Heart J 1992; 13:1658-1664

(3.) Dommisse J, Commerford PJ, Levetan B: Balloon valvuloplasty for severe mitral valve stenosis in pregnancy. a report of 11 cases. S Afr Med J 1996; 86:1194-1196

(4.) Glantz JC, Pomerantz RM, Cunningham MJ, et al: Percutaneous balloon valvuloplasty for severe mitral stenosis during pregnancy: a review of therapeutic options. Obstet Gynecol Surv 1993; 48:503-508

(5.) Mangione JA, Zuliani MF, Del Castillo JM, et al: Percutaneous double balloon mitral valvuloplasty in pregnant women. Am J Cardiol 1989; 64:99-102

(6.) Onderoglu L, Tuncer ZS, Oto A, et al: Balloon valvuloplasty during pregnancy. Int J Gynaecol Obslet 1995; 49:181-183

(7.) Oto MA, Kabuku M, Ovunc K, et al: Percutaneous balloon valvuloplasty for severe mitral stenosis in pregnancy. four case reports. Angiology 1997; 48:463-467

RELATED ARTICLE: KEY POINTS

* The normal hemodynamic changes associated with pregnancy are usually well tolerated.

* In the presence of mitral stenosis, previously asymptomatic women can become seriously compromised by the decreased cardiac output caused by the stenosis and the increased intravascular volume of pregnancy.

* Percutaneous balloon mitral valvuloplasty is known to be a safe and effective procedure during a singleton pregnancy.

* This procedure also appears to be safe and effective in the presence of a twin gestation.

From the Department of Maternal-Fetal Medicine, Sarasota Memorial Hospital, Sarasota, Fla.

Reprint requests to Felice Baron, MD, Perinatal Center of Sarasota Memorial Hospital, 1921 Waldemere St, Suite 401, Sarasota, FL 34239.