Thông tin tài liệu
FIG 10.4 Ideal fetal position, with the fetal left chest anterior The cannula has an unobstructed pathway from the maternal abdomen to the left ventricular apex Once the apex is punctured, the guidewire and coronary angioplasty catheter are positioned for balloon dilation across the aortic valve (Modified from Tworetzky W, Wilkins-Haug L, Jennings RW, et al Balloon dilation of severe aortic stenosis in the fetus: potential for prevention of hypoplastic left heart syndrome: candidate selection, technique, and results of successful intervention Circulation 2004;110[15]:2127.) Laparotomy is reserved only for select cases in which optimal fetal positioning is unable be achieved with external version or imaging is limited.26 Under ultrasound guidance, a 19-gauge cannula and stylet needle are advanced through the maternal abdomen, uterine wall, and fetal chest wall, and the LV apex is punctured (Fig 10.5, Video 10.1) After stylet removal and evidence of blood return confirming intracardiac cannula position, a 0.014-inch guidewire is manipulated across the LV outflow tract into the ascending aorta A coronary angioplasty balloon is advanced over the wire, positioned across the aortic valve annulus, and inflated, typically at least two times, to 100% to 120% of the size of the aortic annulus (Video 10.2).13,27 FIG 10.5 Needle insertion into the left ventricular apex and aimed toward the left ventricular outflow tract Technical success is confirmed by color Doppler demonstrating a broader jet of antegrade flow across the aortic valve and/or the presence of aortic regurgitation (Video 10.3) After cannula removal, the fetus is monitored for at least 30 minutes in the operating room The most common complications, which occur in up to 40% of fetuses, are bradycardia, ventricular dysfunction, and hemopericardium.23 Bradycardia and dysfunction are treated with intracardiac epinephrine and atropine, typically with brisk response.28 If the hemopericardium is small and hemodynamically insignificant, then no intervention is performed If the hemopericardium is moderate to large and/or there is associated hemodynamic instability, then pericardiocentesis is performed In 2017 the Boston group reported technical success in 101 of 123 patients (83%) who underwent fetal aortic valvuloplasty from 23.9 to 32 weeks Greater success, up to 94%, was noted in the latter half of the experience, as would be expected after an initial learning curve An 11% risk of fetal demise (14 of 123) was also reported, mostly from the early experience from 2000 to 2008 Most of these deaths occurred within 24 hours of the procedure.29 The use of laparotomy has also substantially decreased with greater experience with fetal cardiac intervention.26 Importantly, no significant maternal morbidity has been noted.29,30 Postnatal Outcome and Management Technically successful fetal aortic valvuloplasty has been shown to alter the hemodynamics31; myocardial performance as determined by both tissue Doppler imaging and strain mechanics25,32,33; and growth of left-sided heart structures in utero.23 In 2014 the Boston group reported the postnatal outcomes of the first 100 patients who underwent fetal aortic valvuloplasty Most importantly, technically successful intervention resulted in larger left-sided heart structures at the time of birth (Fig 10.6) Among live-born patients (n = 88), 31 were managed as biventricular from birth and seven were converted to a biventricular circulation after various stages of single ventricle palliation Of the technically successful interventions, 45% resulted in a biventricular outcome postnatally.34 FIG 10.6 Four-chamber views of the heart in two patients, with the preintervention fetal echocardiograms on the left and the postnatal echocardiograms on the right (A–B) This patient had a technically unsuccessful fetal aortic valvuloplasty and was managed with staged
Ngày đăng: 22/10/2022, 11:21
Xem thêm:
