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Impact of Tricuspid Valve Disease on the Outcome of Pregnancy in Egyptian Females with Mechanical Valve Prosthesis
Zeinab A. Ashour, M.Hassan Hussein,
Department of Cardiology and Department of Public
Faculty of Medicine, Cairo University
Cairo - Egypt
Introduction and Background
Patients and Methods
Background and Objective: The risk of pregnancy in patients with mechanical valve prosthesis has traditionally been attributed to the use of oral anticoagulants. The impact of residual hemodynamic Tricuspid valve disease (TVD) after corrective surgery has not been examined. Our aim was to determine the effect of TVD on fetal and maternal outcome of pregnancy in patients with mechanical valve prosthesis.
Methods: We examined the data of 101 pregnancies in 69 females with mechanical valve prosthesis. Their ages ranged from 19 to 45 years. Fourteen females with 21 pregnancies suffered from TVD severe enough to necessitate diuretic use (Alductone 100-150 mg daily and/or Frusemide 40mg).
Results: In presence of TVD, fetal wastage rate was significantly higher (81% versus 34%, p < 0.001). This was due to spontaneous abortions (52%), premature delivery (38%) and intrauterine fetal death (10%). No maternal complications occurred in females suffering from TVD, except for bleeding in one patient. Atrial fibrillation, left ventricular enlargement and Warfarin use in the first trimester were not significant determinants of outcome of pregnancy in terms of fetal loss or maternal complications.
Conclusion: The presence of TVD adversely affects the fetal outcome of pregnancy in patients with mechanical valve prosthesis. Warfarin use did not show a significant impact. Fetal loss may be due to placental insufficiency because of systemic congestion or reduced placental blood flow induced by diuretic use.
Introduction and background:
The risk of pregnancy in patients with mechanical valve prosthesis (VP) has traditionally been attributed to the use of oral anticoagulants necessary to maintain the integrity of the mechanical prosthesis. The impact of residual valvular lesions has not been a point of interest in these patients, as it is assumed that these were corrected at surgery. Whereas Mitral and Aortic valve replacements have proven to be successful and have stood the test of time, Tricuspid valve replacements have become unpopular due to the high incidence of thrombosis and malfunction (1-7) . Tricuspid valve repair can be done in several ways, by either a ring or an annuloplasty (5-7). However in rheumatic affection of the Tricuspid valve, other problems arise: the valve may not be solely incompetent, it may be stenotic as well; the incompetence may not be solely due to annular dilatation, actual fibrosis and shortening of the cusps may occur rendering repair more difficult. Finally, there have been reports about late occurrence of Tricuspid incompetence after Mitral valve replacement, that had not been present at the time of surgery (8) This is most probably due to progression of fibrosis in the cusps affected by rheumatic fever. The patients suffering from Tricuspid valve disease (TVD) after valve surgery are in a unique situation where the hemodynamic burden is purely due to the Tricuspid valve. This problem is of importance in Egypt, where rheumatic valvular heart disease is still common , affecting mainly the young population. As a consequence, a large portion of Egyptian females with VP are in the childbearing age. Those who do not suffer from TVD are prone to develop it with time. In this study we tried to determine the effect of TVD on the outcome of pregnancy in Egyptian females with VP in terms of maternal as well as fetal morbidity and mortality.
Patients and Methods:
Three hundred and forty eight (348) female patients were followed up in the Cairo University prosthetic valve clinic from 1986 to 1999. Of these, 70 patients became pregnant with a total of 108 pregnancies. Five patients were lost to follow up and three pregnancies are still ongoing. These were excluded from the analysis, leaving 67 patients with 100 pregnancies. All patients had mechanical prosthesis, 43 in the Mitral position, 12 in the Aortic position, and 12 had a double valve replacement. Fourteen patients with 23 pregnancies suffered from TVD, predominantly incompetence, which was clinically apparent and severe enough to necessitate diuretic use in form of Alductone 100-150 mg and/or Frusemide 40mg daily. The pregnancies were divided into two groups : Group A , in which the mother suffered from Tricuspid incompetence, and Group B, in which the mother did not have any clinically manifest TVD
Of 100 pregnancies, 56 (56%) resulted in a healthy baby. Fetal loss occurred in 44%, and was due to abortion in the 1st trimester ( 28%), intrauterine fetal death (4%), stillbirth (3 %), neonatal death due to meconium aspiration (1%), prematurity (2%), RH incompatibility (2%) and preterm death of the mother (4%). In 23 of the 100 pregnancies, the mother suffered from Tricuspid incompetence severe enough to necessitate diuretic use. These pregnancies did not fare well, 17 of them ending in an abortion or intrauterine fetal death. When comparing the results to those of patients not suffering from Tricuspid incompetence, there was a statistically significant difference.(p = 0.001) see table 1
Of the 100 pregnancies followed up, 15 developed complications and 5 ended fatally. The maternal complications included valve malfunction (thrombosis in 8 patients and infective endocarditis in 1 patient), postpartum hemorrhage (5 patients) , bleeding during pregnancy due to placenta brevia (1 patient), toxemia of pregnancy (1 patient) and Cesarean section was needed in 2 patients.
We postulated that Tricuspid incompetence may aggravate the tendency to post partum hemorrhage, and increase the likelihood of infective endocarditis, however the presence of TVD did not have any impact on the maternal outcome of pregnancy. (see table 1) The most common and most serious complication was acute valvular malfunction. In all cases of acute valvular obstruction, the patient had received heparin in the 1st trimester with the exception of a woman who developed infective endocarditis. Five of these patients died and 4 needed reoperation, which was performed successfully. This led us to examine the effect of type anticoagulation on the outcome of pregnancy (see table 2).
Table 1: Effect of TVD on the outcome of pregnancy
Anticoagulation during the first trimester
Of the 100 pregnancies in patients with VP, 66 were put on a strict regimen of subcutaneous heparin, 5000 IU every eight hours or 10 000 IU every 12 hours. As most of these patients were from remote rural areas, a proper follow up of aPTT was not possible. In the other 34 pregnancies, the mother continued oral anticoagulant (warfarin) intake, so as to adjust the prothrombin time to 2.5 of the control and later, when INR became available, to adjust the INR to 2 - 2.5 . Of the 66 pregnancies initially put on heparin, 38 (57.5%) resulted in a healthy baby versus 18 out of 34 (52.9%) in the group on Warfarin. The difference was statistically insignificant (see table 2). As mentioned before, maternal outcome was affected by the type of anticoagulation used.
Table 2: Effect of Warfarin use in the 1st trimester on the outcome of pregnancy
We attempted to determine the role of TVD on both fetal and maternal outcome of 100
pregnancies in Egyptian females with VP. The fetal loss rate was high, 46 %. Of these, 28
% were due to abortions in the 1st trimester. Other causes included
intrauterine fetal death, meconium aspiration, RH incompatibility and maternal death
during pregnancy . Warfarin embryopathy was noted only in one case of stillborn twins. The
fetal loss rate reported in the literature varies from 8.5 % to 66% (9-20).
The presence of TVD necessitating diuretic use was associated with a higher degree of fetal loss. This has not been previously reported in the literature,only one investigator mentions repeated miscarriages as an indication for Tricuspid annuloplasty (21). It may be due to the use of diuretics, the low cardiac output or due to the systemic congestion present in these cases, and needs further evaluation to determine the cause. Given the fact that 11% (38 of 348 patients ) of the female population with VP followed up at Cairo University and 20 % (14 of 68) patients of those who became pregnant have residual Tricuspid incompetence warranting diuretic use, this phenomenon should be investigated. TVD did not affect maternal outcome, although few reports mentioned an increased likelihood of infective endocarditis (22,23).
The use of Warfarin in the first trimester is still controversial. It is reported to be teratogenic especially when taken drin the 6th to 12th week of gestation (24). However, recent reports have indicated that the much feared Warfarin embryopathy is extremely rare (12,14) and that fetal loss may be dose dependent (15). Furthermore there have been reports that even full heparinization does not provide reliable anti-coagulation to the mother, thus putting her at risk for thromboembolism and valvular malfunction (12-16). When comparing in our series females who received Warfarin during the first trimester with those who received heparin no significant difference was found as concerns fetal outcome. However, 60% of the complication rate in mothers was due to mechanical valve obstruction and 53% was due to thrombo-embolism, all of which occurred in patients who were put on heparin in the 1st trimester. This confirms the findings of other investigative groups that heparin does not provide adequate protection against thromboembolism in these patients. Other maternal complications were all pregnancy related except for post partum hemorrhage in one patient, which could only be explained by the oral anticogulant therapy. They included malpositions necessitating Cesarean sections, placenta brevia, toxemia of pregnancy and post partum hemorrhage due to retained placenta. The maternal complication rate was 14.8%, which is quite comparable to international figures ranging from 10 % to 15% .(12, 17, 18).
We conclude that patients with VP have a high incidence of fetal loss and maternal complications Warfarin did not seem to have a significantly worse effect on the fetal outcome of pregnancy compared to heparin, but was more effective in preventing thromboembolic complications and valvular malfunction in the mother. TVD was associated with an extremely high rate of fetal loss, and this association warrants further investigation and studies
References:1- Kouchoukos NT; Stephenson LW: Indications for and resluts of tricuspid valve replacement. Adv Cardiol 1976;17:199-206
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