Evaluation of balloon angioplasty of coarctation restenosis by magnetic resonance imaging

[Magnetic resonance imaging in long-term assessment after surgery for aortic coarctation]

OBJECTIVES

Spin echo or gradient echo magnetic resonance imaging provides enough information to plan patient management and can be completed with the use of three-dimensional magnetic resonance angiography to evaluate the need for reintervention, assess follow-up, or discharge the patient.

PATIENTS AND METHODS

From 1990-2003, we evaluated 101 patients after initial corrective surgery for aortic coarctation at the age of 3.1 +/- 3 years, with subsequent postoperative assessment at 1 year and again 12.4 +/- 4.2 years later. No mortality was registered during the follow-up. Corrective surgery was performed in 32 patients (31.6 %) before the first month of life. All the patients were evaluated with spin-echo and echo gradient and 34 were evaluated with magnetic resonance angiography. The patients were classified into two groups: group A consisted of 68 patients (11 < 1 month old) with no complications. End-to-end anastomosis was performed in 55, the Alvarez technique in five, the Waldhausen technique in six, and conduit in two. Group B consisted of 33 patients complicated with early aortic recoarctation (21 corrected before the age of 1 month). End-to-end anastomosis was performed in 29, the Alvarez technique in two, and grafting in two. During the follow-up, 43 reinterventions were performed. Isthmus diameter/descending aorta diameter at the diaphragmatic level and repaired site diameter/descending aorta diameter at the diaphragmatic level were measured.

RESULTS

Group A: the isthmus diameter/descending aorta diameter at the diaphragmatic level index was 0.92 +/- 0.08 and the repaired site diameter/ descending aorta diameter at diaphragmatic level index was 0.90 +/- 0.05. Twenty-three patients were assessed by means of three-dimensional magnetic resonance angiography, which revealed two late stenosis (one in a 10-year-old patient with an end-to-end anastomosis performed previously, and another in an 18-year-old patient with a proximal and distal obstructed conduit). Group B: the isthmus diameter/descending aorta diameter index was 0.84 +/- 0.1 and the repaired site diameter/ descending aorta diameter index was 0.82 +/- 0.11. Eleven patients were assessed by means of three-dimensional magnetic resonance angiography, which revealed five stenosis indexes (0.53-0.73) surgically corrected before the age of 2 months, four with an initial technique based on end-to-end anastomosis and one with a graft.

CONCLUSIONS

Our results support the influence of young age, the use of end-to-end anastomosis and grafts in recoarctation and their late influence on recurrent recoarctation. The patients in group A were discharged in childhood or adulthood after periodic follow-up every 5 years with magnetic resonance angiography for 18 years with results within the normal range, while patients in group B required longer follow-up.

Comparison of angioplasty and surgery for neonatal aortic coarctation

BACKGROUND

The efficacy of balloon dilatation as primary treatment for neonatal aortic coarctation remains controversial.

METHODS

A retrospective comparison between balloon angioplasty and surgery for the treatment of neonatal aortic coarctation was undertaken on 57 neonates younger than 40 days of age (angioplasty, 23 patients; surgery, 34 patients) treated between 1994 and 2004.

RESULTS

Cohorts were similar with respect to the preinterventional variables of age, weight, upper extremity systolic blood pressure, coarctation gradient, degree of aortic arch hypoplasia, associated conditions, and mean follow-up (angioplasty, 36 months; surgery, 38 months). Among the angioplasty group, 13 patients (57%) required surgery, and 8 required a second balloon dilatation, of whom 3 patients had an aortic aneurysm. Among the surgery cohort, 6 patients experienced recurrence (18%) after either SFA (3) or XETE anastomosis repair (3). All were successfully treated with balloon angioplasty. Actuarial freedom from any intervention was significantly greater in the surgery cohort as was the degree of aortic arch growth. At latest follow-up, antihypertensive medication was required in 3 of 9 angioplasty patients (33%) and 2 of 27 surgery patients (7%). No repeat intervention was required in the 13 patients who underwent angioplasty followed by surgery.

CONCLUSIONS

Primary angioplasty is palliative treatment for neonatal aortic coarctation, but it is the treatment of choice for recurrence after surgery. Surgery for neonatal aortic coarctation is associated with fewer reinterventions, improved aortic arch growth, no aortic aneurysm formation, and decreased need for antihypertensive medication when compared with neonates treated primarily with balloon angioplasty.

Magnetic resonance and computed tomographic evaluation of congenital heart disease

Magnetic resonance imaging (MRI) and contrast-enhanced computed tomography (CT) provide noninvasive visualization of morphologic changes in pediatric and adult patients with congenital heart disease, as well as the functional changes caused by the underlying morphologic abnormalities. Clinical experience with MRI is richer than that with fast CT, but CT appears to provide accurate and high-quality imagery for diagnosis. The two modalities may be complementary. That is, intracardiac anatomy is so well depicted by MRI, and CT provides exquisite images of the great vessels. Furthermore, in adult patients, MR and CT are helpful in demonstrating and quantitating physiologic changes superimposed by acquired cardiovascular disease on the underlying congenital malformations. Using MRI, spin echo acquisitions provide the image data for evaluation of morphologic changes, and gradient reversal techniques add functional and flow data to complement morphologic changes. Contrast-enhanced electrocardiographic (ECG)-gated multidetector and electron beam CT examination provide morphologic information and may be used as a data set for off-line functional quantitation.

MR imaging of congenital heart disease

MR examination of patients with congenital heart disease is a useful means of explicitly demonstrating chamber morphology and, in particular, morphologic changes caused by physiologic changes brought on by particular defects. Use of MR techniques allows characterization of chamber morphology for determination of cardiac connections and great artery relationships. The high-contrast resolution of spin echo acquisition provides important morphologic detail. Cine gradient echo techniques complement spin echo acquisition by providing functional and flow information. Although MR examination complements echocardiographic investigation in pediatric and adult patients, is may be useful for replacing angiocardiography, shortening examination time, and decreasing morbidity in diagnostic workups of these patients.

Extra-anatomic aortic bypass via sternotomy for complex aortic arch stenosis in children

OBJECTIVE

Recurrent aortic narrowing after repair of aortic coarctation or interrupted aortic arch, as well as diffuse, long-segment aortic hypoplasia, can be difficult to manage. Extra-anatomic ascending aorta-descending aorta bypass grafting through a sternotomy is an alternative approach for this problem.

METHODS

Since 1985, 19 patients aged 2 months to 18 years (mean 10.7 years) underwent extra-anatomic bypass with 10- to 30-mm Dacron grafts. The initial diagnosis was coarctation with hypoplastic arch in 15, interrupted aortic arch in 3, and diffuse long-segment aortic hypoplasia in 1. Seventeen of the children had a total of 22 previous operations: transthoracic interposition or bypass graft (n = 7), end-to-end anastomosis (n = 7), subclavian arterioplasty (n = 6), and synthetic patch (n = 2). The mean time from initial repair was 8.0 years (range 0.6-18 years). Three children had previous sternotomies. Cardiopulmonary bypass was avoided in all but 6 patients (5 with simultaneous intracardiac repairs).

RESULTS

No hospital or late deaths occurred. On follow-up from 4 months to 14.7 years (mean 7.9 years), no reoperations for recurrent stenosis were performed. Two patients have arm-to-leg pressure gradients: 20 mm Hg at rest in 1 patient and a 60-mm Hg systolic exercise gradient with no resting gradient in the other. One patient required exclusion of an aortic aneurysm at the old coarctation repair site 13 years after extra-anatomic bypass. Three children had subsequent successful cardiac operations.

CONCLUSIONS

Extra-anatomic bypass is an effective and relatively easy approach for selected cases of complex or reoperative aortic arch obstruction. It should be considered as an alternative operative technique for complex aortic arch reconstruction.

MR imaging of coarctation of the aorta and its postoperative complications in adults: assessment with spin-echo and cine-MR imaging

To evaluate the ability of ECG-gated spin-echo (SE)-MR imaging vs. cine-MR imaging to assess coarctation of the aorta, 11 patients aged 15-45 years, with known or suspected coarctation of the aorta, and five patients suspected of re-stenosis or postoperative false-aneurysms after coarctation repair were examined by multisection SE-MR imaging and single-section multiphase cine-MR imaging on a 1.0 Tesla device. Aortography was performed in 15, and surgery in 14 of these 16 patients. Qualitatively, the location, severity, and length of the coarctation were shown in all cases with MR imaging, as well as the relationship with the arteries arising from the aortic arch. The respective sensitivities and specificities in the assessment of severity of stenoses were 86% and 100% for SE MR images, and 100% and 100% for cine-MR images. Cine-MR imaging was superior to SE imaging in stenosis diameter assessment with contrast angiography as reference, as well as to identify the site of leakage in cases of postoperative pseudoaneurysm. Pre-stenotic dilation or post-stenotic aneurysm, collateral channels, and associated malformations were better identified on SE images. Quantitatively, a better stenosis diameter correlation was found between cine-MR images and angiography than between SE-MR images and angiography (r=0.99 vs. r=0.78; p=0.001 vs. p=0.004), related to overestimation of stenoses with SE-MR imaging. The use of a combination of spin-echo and cine-MR imaging correlates well with conventional angiographic findings in this small series of patients with coarctation of aorta or postoperative pseudoaneurysmal complications. Cine-MRI can provide anatomic information that is equivalent to angiography for surgical planning.

Balloon angioplasty of recurrent coarctation: a 12-year review

OBJECTIVES

This study was undertaken to investigate the long-term outcome of balloon angioplasty for recurrent coarctation of the aorta in a large series of patients.

BACKGROUND

Balloon angioplasty has become the standard treatment for residual or recurrent aortic coarctation. Despite the widespread use of this treatment modality, there are few data outlining the long-term outcome of a large patient cohort.

METHODS

Clinical, echocardiographic, hemodynamic and angiographic data on 90 consecutive patients who underwent balloon angioplasty between January 1984 and January 1996 were reviewed.

RESULTS

Mean systolic pressure gradients were reduced from 31 +/- 21 to 8 +/- 9 mm Hg after dilation (p = 0.0001). The mean diameter of the stenotic site, measured in the frontal and lateral views, increased by 38% and 35%, respectively (p = 0.001). Neurologic events occurred in two patients, with one death. An aortic tear occurred in one patient, requiring surgical intervention. Optimal results were defined as a postprocedure gradient < 20 mm Hg and were obtained acutely in 88% of patients. At long-term follow-up (12 years), 53 (72%) of 74 patients with an early optimal result remained free from reintervention. Transverse arch hypoplasia, defined as an arch dimension < 2 SD below the mean for age, was the primary predictor of the need for reintervention.

CONCLUSIONS

Although the majority of patients undergoing percutaneous balloon angioplasty for recoarctation of the aorta will achieve long-term benefit, the need for further surgical intervention in those with transverse arch hypoplasia remains high.

Mechanism of balloon angioplasty in children with arterial stenosis assessed by intravascular ultrasound and angiography

Fifteen patients were examined before and immediately after balloon angioplasty with a 4.3F, 30 MHz rotational tip intravascular ultrasound system. In 12 (80%) patients, 13 procedures could be analyzed because of sufficient image quality. The lesions for intravascular ultrasound (IVUS) study consisted of pulmonary arterial stenosis in 4 patients, Blalock-Taussig shunt stenosis in 3, coarctation of the aorta in 2, subclavian artery stenosis in 1, renal artery stenosis in 1, and ductus arteriosus in 1. Three distinctive morphologic types were identified: Group I had arterial stretching (3 patients); group IIa had superficial tearing (3); group IIb had deep intimal-medial tearing (5); group III had dissection (2). In the narrowest site, minimal and maximal luminal diameters, luminal area before and after balloon angioplasty were 3.5 +/- 1.8 mm vs 4.5 +/- 2.5 mm, 4.1 +/- 2.1 mm vs 5.4 +/- 3.5 mm, and 49.8 +/- 30.2 mm vs 88.3 +/- 45.2 mm2, respectively. The recoil value of group IIb with appropriate balloon angioplasty was approximately 0.3. IVUS may be an useful modality for evaluating the morphologic mechanism of dilatation after balloon angioplasty.

Evaluation of aortic coarctation after surgical repair: role of magnetic resonance imaging and Doppler ultrasound

OBJECTIVE

To compare the usefulness of magnetic resonance imaging (MRI) and Doppler ultrasound with that of cross sectional echocardiography and oscillometric blood pressure measurement for the evaluation of aortic coarctation after surgical repair.

DESIGN

Prospective study. Aortic diameters measured by cross sectional echocardiography, MRI, and angiography (selected cases) and functional data determined by physical examination, oscillometric blood pressure measurement, and continuous wave Doppler.

SETTING

Tertiary referral centre.

PATIENTS

40 patients aged 2-28 years (mean 10.6 years) who had had surgical correction of aortic coarctation (mean follow up 5.7 years).

RESULTS

In all patients MRI gave diameter measurements of the aortic arch and the thoracic aorta whereas in half of them cross sectional echocardiographic measurement of the isthmic region failed. The correlation coefficient for aortic diameters measured by MRI and angiography was 0.97 and that between MRI and echocardiography was 0.89. Peak velocities in the descending aorta correlated better with residual narrowing of the aortic isthmus or distal aortic arch or both than systolic blood pressure gradients between the upper and lower limbs. A peak velocity of < 2 m/s in the descending aorta during systole excluded important restenosis. Prolongation of anterograde blood flow during diastole always indicated a morphological abnormality--either important restenosis or aneurysmal dilatation.

CONCLUSIONS

MRI was better than cross sectional echocardiography for imaging the aortic arch after coarctation repair and measuring its diameter. Peak velocity in the descending aorta correlated better with residual stenosis than did the systolic blood pressure gradient between the upper and lower limbs and this index could be used to indicate a need for MRI.

Balloon angioplasty for aortic recoarctation in children: initial and follow up results and midterm effect on blood pressure

OBJECTIVE

To assess the direct and follow up results of balloon angioplasty for aortic recoarctation with respect to the type of initial operation and to determine the midterm effect on systolic blood pressure.

DESIGN

Prospective study of invasive haemodynamic and angiographic data and non-invasive data on upper body blood pressure.

SETTING

Tertiary referral centre for paediatric cardiology.

SUBJECTS

24 infants and children (age 0.3-16.2 years, mean 5.9 years) who had had surgical correction for coarctation (end to end anastomosis (14 patients) subclavian flap angioplasty (nine), patch angioplasty (one)).

MAIN OUTCOME MEASURES

Peak systolic gradient over the recoarctation and aortic diameters before and directly after angioplasty and at follow up. Upper body blood pressure before and after angioplasty and at latest follow up.

RESULTS

Mean peak systolic gradient initially decreased from 35 (15) to 12 (9) mm Hg (p < 0.001) and was 9 (10) mm Hg at follow up after 1.4 (0.5) years. Patients with a subclavian flap repair showed a slight further decrease in the residual gradient at follow up (p < 0.05). The coarctation diameter increased from 5.3 (2.6) to 7.7 (2.5) mm (p < 0.001), and a further increase to 9.3 (2.9) mm (p < 0.01) was present at follow up after 1.4 (0.5) years without significant changes in other aortic diameters. Upper body systolic blood pressure decreased from 138 (24) to 115 (17) mm Hg after balloon angioplasty, and the effect on blood pressure persisted at a mean follow up of 3.7 years. One patient died of ventricular failure. Femoral artery thrombosis occurred in three patients. In one patient a small aneurysm occurred that had not increased at follow up. In one patient restenosis after angioplasty was redilated successfully. In one patient dilatation of a residual stenosis after angioplasty failed.

CONCLUSION

Balloon angioplasty for recoarctation is effective and is associated with accelerated growth of the dilated segment at follow up in many patients. The complication rate is acceptable. Midterm follow up shows persistent relief of upper body hypertension in most patients.

Dissection following balloon angioplasty of aortic coarctation: review of the literature

Balloon angioplasty of the coarctation of the aorta can result in intimal or medial or even adventitial dissections as demonstrated by in vitro studies and animal experiments. As a typical sign of stretching of the aortic wall, patients complain of pain during the angioplasty procedure. In the literature, aortic wall rupture and ventricular fibrillation during the procedure are reported. Additional sudden deaths can occur within 40 hours after the procedure. Mortality ranges from 0.1% to 2.5%. By transesophageal echocardiography, monitoring of balloon angioplasty, control of the positioning of the balloon, and control of the results and detection of complications are possible. Intimal as well as medial dissections can be detected with observed healing for intimal but also medial dissections. In order to avoid the patient's discomfort, intraaortic ultrasound will be used in the future, when major methodological improvements are done. Computed tomography demonstrates medial dissections but is not able to visualize intimal dissections. Using computed tomography and magnetic resonance after angioplasty of the coarctation of the aorta, irregularities are described in up to 17% of the patients. For angiography, a low detection rate of medial dissections has to be expected, when not biplane angiographies of the whole thoracic aorta are performed. Medial dissections can be seen, but intimal dissections are missed. In conclusion, a review of the literature demonstrates a high incidence of intimal and medial dissections after angioplasty of the coarctation of the aorta with spontaneous healing in most patients. As is the way with coronary angioplasty, aortic wall ruptures are rare, but stand-by surgery is necessary.

Balloon angioplasty of native coarctation of the aorta in adolescents and young adults

Balloon angioplasty of native coarctation of the aorta was performed in 35 consecutive adolescents and young adults, aged 14 to 37 years (mean 22.6 +/- 7.1). Twenty-eight (80%) patients had isolated discrete coarctation, six (17.1%) had tubular hypoplasia of the aortic isthmus, and one (2.9%) had hypoplasia of the post-coarctation aorta. The peak systolic pressure gradient decreased from 78.5 +/- 23.9 to 15.7 +/- 11.6 mm Hg (p less than 0.001), and the mean coarctation diameter increased from 4.7 +/- 2.4 to 13.1 +/- 2.7 mm (p less than 0.001) immediately after angioplasty. Patients with discrete-type coarctation had significantly less residual gradient than patients with long-segment tubular coarctation (12.3 +/- 10.7 vs 27.2 +/- 6.6 mm Hg, p less than 0.01). On recatheterization and angiography in 26 patients at 12.6 +/- 1.5 months after dilatation, there was no significant change in gradient (15.5 +/- 13.3 mm Hg) and diameter (13.1 +/- 1.8 mm) from the immediate post-angioplasty results. However, two patients had an increase in gradient and three had small aortic aneurysms with no change in appearance on restudy after 2 years. After 3 to 67 months' (mean 32.7 +/- 19.2) follow-up, all patients showed continued clinical improvement. Hypertension was relieved in 37.5% (12/32) and improved in 59.4% (19/32). Our experience suggests that balloon angioplasty of native aortic coarctation in adolescents and young adults is safe and highly effective with sustained improvement on intermediate-term follow-up.

Nuclear magnetic resonance imaging of the palliative operation for hypoplastic left heart syndrome

Electrocardiographic-gated nuclear magnetic resonance (NMR) imaging has been shown to be effective for the evaluation of congenital heart disease, particularly in supracardiac regions. This study evaluated the postoperative status after a stage I palliative operation (Norwood procedure) for hypoplastic left heart syndrome. The NMR images from three patients were compared with those of angiography and depicted all components of the reconstructed supracardiac and intracardiac anatomy after this operation. Nonobstructive anastomosis of the main pulmonary artery to the proximal aorta was clearly demonstrated in each patient. The caliber of the central or branch pulmonary artery, patency and caliber of the systemic to pulmonary artery shunt and the size of the atrial communication were also depicted in each patient and these findings corresponded with angiographic results. The results suggest that NMR imaging is effective for assessing the results of initial palliative surgery for hypoplastic left heart syndrome, which seems to be important for managing patients before subsequent definitive surgery.

Balloon angioplasty of coarctation of the aorta evaluated with intravascular ultrasound imaging

Intravascular ultrasound images were employed to evaluate aortic coarctation before and after balloon angioplasty. Measurements obtained with use of an ultrasound imaging catheter correlated well with measurements made with digital aortography, both in the area of coarctation and in areas proximal and distal to it. The intravascular ultrasound images dramatically revealed dissection of the aortic wall and an intimal flap that was not appreciated on cineaortography or digital subtraction angiography. Intravascular ultrasound imaging may yield important morphologic information unavailable by other imaging techniques. Such information may allow more precise definition of the results of intravascular procedures and improve understanding of lesion characteristics predictive of a successful outcome.