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Case Report
Safety and Feasibility of the Radial Approach for Primary Angioplasty in Acute Myocardial Infarction During Pregnancy
June 2002
Even though myocardial infarction during pregnancy is a rare occurrence, it is associated with a 37–50% mortality rate.1 Acute myocardial infarction (AMI) in pregnancy was first described by Katz in 1922 and has a reported incidence of 1 in 10,000 pregnancies.2 The treatment for AMI in a nongravid patient is either thrombolysis or percutaneous transluminal coronary angioplasty (PTCA).3 Recently, primary stenting and the use of antiplatelet agents during coronary interventions have been shown to improve the outcome of patients with myocardial infarction.4 There are only a few reports on primary angioplasty in AMI during pregnancy in the literature and none about primary angioplasty via the transradial approach in this setting.
We report here a case of successful primary angioplasty in AMI performed via the transradial approach in a 37-year-old, 14-week pregnant woman. The risks and benefits of the transradial approach for primary angioplasty during pregnancy are discussed below.
Case Report. A 37-year-old woman gravida 4, para 3 presented at 14 weeks of gestation to the emergency department within 8 hours of substernal chest pain onset. The pain was constricting, severe in intensity and not relieved by sublingual nitroglycerin spray. Her previous deliveries were normal. Her cardiac risk factors were heavy cigarette smoking, hypercholesterolemia and a family history of ischemic heart disease. She denied any drug abuse except minerals and vitamins during pregnancy. On physical examination, she was hemodynamically stable and cardiovascular examination was within normal limits. Initial electrocardiogram showed ST-segment elevation in leads V1–V3, but at the time of hospitalization there was Q wave in the same leads (Figure 1). Her CPK was 1,389 IU/L with MB fraction of 189 IU/L. Troponin I was 9.08 IU/L. Echocardiography demonstrated moderate hypokinesia of the anterior wall and *severe hypokinesia of the septum with mild left ventricular systolic dysfunction (50% left ventricular ejection fraction) without left ventricular thrombus. The patient had persistent chest pain despite treatment with intravenous aspirin, heparin and nitrates. Because the risk to the mother and fetus were thought to be lower with primary angioplasty than with thrombolysis and also because our usual protocol for acute myocardial infarction is primary angioplasty, the patient was taken to the cardiac catheterization laboratory for coronary angiography and possible intervention. A full obstetric team was present in the catheterization laboratory for continuous monitoring. Abdominal shielding was placed to protect the fetus from radiation. Coronary angiography was performed via the right radial approach. Fluoroscopy time was minimal in consideration of fetal hazards. Coronary angiography revealed a dominant right system with normal right coronary, left main and circumflex arteries. The left anterior descending coronary artery was 3.5 mm in caliber with a 95% eccentric stenosis in the proximal segment and distal TIMI 2 flow (Figure 2).
Given our usual protocol and because of the high risk associated with thrombolysis in this patient, we decided to perform primary angioplasty via the radial approach. As per our protocol for the transradial approach, the patient received 5,000 IU of heparin along with 3 mg of verapamil. Subsequent activated clotting time (ACT) was 222 seconds. A 6 French EBU 4 guiding catheter (Medtronic, Inc., Minneapolis, Minnesota) was inserted and the lesion was crossed with an 0.014´´ BMW guidewire (Guidant Corporation, Temecula, California). The lesion was dilated with a 3.5 x 20 mm Viva balloon (Boston Scientific/Scimed, Inc., Maple Grove, Minnesota) inflated first at 5 atmospheres (atm) for 15 seconds and then at 8 atm for 1 minute (Figure 3). Optimal PTCA result with TIMI 3 distal flow was subsequently achieved and persisted even after 5 minutes (Figure 4). Because of optimal PTCA results and possible deleterious side effects of ticlopidine, we did not implant a stent. Total fluoroscopic time was 13 minutes. Given the low incidence of acute myocardial infarction during pregnancy, the patient was evaluated for potential hypercoagulable states. Anticardiolipin antibodies, lupus anticoagulant, protein C and S, PT and PTT were within normal limits. The patient was kept on low-molecular-weight heparin for 5 days and discharged on day 8 uneventfully on 160 mg of aspirin daily. After 2 months of follow-up, she was asymptomatic (New York Heart Association class I) with normal left ventricular function (62% left ventricular ejection fraction) on echocardiogram.
Discussion. AMI during pregnancy is a rare event, with a reported incidence of 1 in 10,000 pregnancies.2 Because of increasing maternal age and a growing smoking habit reported in women, this rate may increase. The reported mortality rate is 37–50% and increases when infarction occurs in the third trimester, in patients under 35 years of age, and in patients who give birth within 2 weeks of infarction and/or undergo a caesarean section.1 Therefore, timely and appropriate management is critical for a better clinical outcome.
In instances when thrombolytic therapy was used in pregnancy complicated by thromboembolic disease,5 there was a resultant increase in maternal mortality (1.2%), pregnancy loss (5.8%) and bleeding (8.1%) compared to normal pregnancy. Thrombolytic therapy was consequently considered a relative contraindication during pregnancy due to the increased risk of maternal and fetal hemorrhage.5 However, one case of systemic and two cases of intracoronary thrombolysis for AMI have been reported in the literature.6–8 The use of antiplatelet agents is the mainstay of percutaneous coronary intervention to prevent ischemic complications, including subacute stent thrombosis. But there is very limited information available in the literature about their use and possible bleeding complications in pregnancy. Sebastian et al. reported a case of primary stenting in AMI during pregnancy with the combined use of abciximab, ticlopidine and aspirin.9 No bleeding complications occurred in the mother or her child, but the authors observed a complete inhibition of platelet aggregation to adenosine diphosphate in the cord blood related to the treatment, which may predispose the infant to intracranial hemorrhage during vaginal delivery.
Furthermore, the teratogenic effects and safety of ticlopidine and abciximab during pregnancy have not been studied and it is not known whether these drugs are excreted in breast milk. However, low-dose aspirin has been used during pregnancy without side effects.10 Despite the significant controversy surrounding the relative benefits of primary PTCA versus thrombolysis in AMI when both are feasible, PTCA is the treatment of choice in patients with AMI and contraindications to thrombolysis. Even though AMI during pregnancy is an indication for PTCA, this is a rare occurrence, and experience is therefore limited as is the availability of percutaneous coronary intervention in the setting of AMI worldwide. To date, there are only 12 reports of coronary intervention during pregnancy available in the literature, but all procedures were performed using the transfemoral approach. Primary PTCA may require intensive anticoagulation, including glycoprotein IIb/IIIa receptor inhibition in addition to heparin and aspirin. Coronary intervention in these patients via the transfemoral approach is associated with an increased incidence of access-site complications.11,12 These vascular bleeding complications are an important cause of increased patient morbidity, longer hospital stay and higher hospital cost.13 There are reports of successful primary PTCA in AMI via the transradial approach,14–16 but there is not a single report on primary PTCA during pregnancy via the transradial approach. We successfully performed transradial primary PTCA in our 14-week pregnant patient. The total procedure time was 32 minutes and total fluoroscopy time was 13 minutes. In our center, we regularly use the transradial approach for elective as well as emergency coronary interventions, including primary PTCA. The average procedure duration of coronary angiography reported by our group was 18 ± 9 minutes and decreased progressively with experience and catheter strategy.17,18 The ACCESS study also confirmed the similarity of total procedure time and fluoroscopy time between transradial and transfemoral approaches in experienced hands, and reported procedure times of transradial PTCA (40 ± 24 minutes) to be similar to transfemoral PTCA (38 ± 24 minutes; p = 0.603) as well as similar fluoroscopy times in the two groups (13 ± 11 minutes for transradial approach versus 11 ± 10 minutes for transfemoral approach; p = 0.061). The ACCESS study concluded that in experienced hands, the transradial technique yields results comparable with those of transfemoral PTCA with near elimination of bleeding vascular complications.19 The CARAFE study also showed near similarity of procedure duration and x-ray time between transfemoral and transradial approaches during coronary angiography, with a total procedure time of 11.2 ± 3.3 minutes by the femoral approach and 12.4 ± 5.8 minutes by the right radial approach.20
We hypothesized that there might be less radiation hazard to the fetus using the transradial approach, apart from fewer vascular bleeding complications compared to the transfemoral approach.
It has already been proven that patient comfort is higher with the transradial approach. In the setting of AMI in pregnancy treated by percutaneous coronary intervention, the transradial approach may help to avoid extra mental and traumatic stress and thus reduce the risk of fetal loss or premature delivery. Earlier patient discharge may result in a decrease in procedure cost.
As the safety of primary PTCA during pregnancy complicated by AMI is established, treatment via the transradial approach may be a safer and more feasible alternative to the transfemoral approach, with fewer fetal and maternal complications due to the reduction in total x-ray exposure and procedure time. This approach is associated with a steep learning curve and requires good technical skills.
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