Klinik und Poliklinik für Innere Medizin II, Hospital of the University Regensburg, Franz-Josef-Strauss-Allee 11, D-93053 Regensburg, Germany
online publish-ahead-of-print 30 November 2004 .
* Corresponding author. Tel: +49 941 944 7258; fax: +49 941 944 7235. E-mail address: christian.hengstenberg{at}klinik.uni-regensburg.de
In grown-up individuals with congenital heart disease, further congenital and acquired co-morbidity is common and has an important effect on outcome and treatment. In 1520% of congenital heart disease, cognitive and intellectual impairment may be present as a feature of co-existing heritable or chromosomal syndromes. Such patients are surviving into adult life with increasing frequency due to a more active treatment approach in childhood.
One problem in the management of adult patients with congenital heart disease is certainly the monitoring of both the cardiac condition and the associated co-morbidity. With the more recent developments in cardiac imaging, there has been a shift from invasive to non-invasive imaging such as magnetic resonance imaging (MRI). This technique provides a 3D reconstruction of anatomy in very high resolution. Especially in the case of coarctation, the MRI technique has been shown to be at least similarly useful for the non-invasive evaluation of the thoracic aorta as compared to high-resolution CT scanning, but without the limitation of radiation.1 With both techniques, there can be substantial variations in two subsequent measurements, wherefore care is to be taken when interpreting the change in diameters in repetitive examinations.1
Coarctation of the aortaa phenotype associated with different disease entities
Coarctation of the aorta may be present as the sole morphology or be associated with a variety of different conditions, such as atrial septal defect,2 aplasia cutis congenital,3 complex disorders involving several systems such as craniofacial anomalies,4 Kabuki make-up (congenital mental retardation) syndrome,5 or Alagille syndrome.6 Furthermore, there are reports that coarctation can also be present in patients with neurofibromatosis where, in a large international database, cardiovascular malformations (including coarctation) were reported in 2.3%, representing a higher proportion of cardiovascular malformations than expected.7 These results indicate that all individuals with neurofibromatosis have careful cardiac auscultation and blood pressure monitoring as part of every examination.7
Arterial hypertension and follow-up of patients with successful repair of coarctation of the aorta
Despite the surgical correction of aortic coarctation, arterial hypertension may persist in adult patients. Arterial hypertension is a dangerous co-morbidity with a high risk of development of atherosclerosis and cardiovascular endpoints, most notably stroke and premature coronary atherosclerosis. The measurement of arterial blood pressure and left ventricular (LV) mass can be assessed in adult patients by several methods, including ambulant blood pressure, 24 h blood pressure monitoring, ECG, echocardiography, and MRI.
In the paper by Vriend et al.,8 in this issue of the European Heart Journal, 107 patients were examined 20 years after surgical correction (mean age at surgery 8 years) with MRI, blood pressure recording, and B mode ultrasound of the carotids. Significant residual narrowing was defined as a remaining pressure gradient of >30 mmHg with resting or exercise-induced hypertension and/or site of repair-to-diaphragmatic aorta ratio <0.7. Thirty-four patients fulfilled these criteria and were consecutively excluded from the study. Seventy-three patients were included in this study, of which 33 (45%) had arterial hypertension. The observation that almost half of patients with no or low gradient on their surgical site have a high degree of arterial hypertension is confirmed by other studies of similar size.9,10 Echocardiographic parameters of LV hypertrophy (LV mass, wall thickness, and diastolic function) have been shown to be dependent on the degree of hypertension rather than on the degree of residual gradient. However, in the study by Vriend et al.,8 a more detailed phenotyping was carried out including MRI scanning and intima-media measurements of the common carotid artery. Multivariable regression analysis was performed and, in post-coarctation patients, mild residual descending aortic narrowing was a strong predictor for systolic blood pressure and carotid intima-media thickness. These data contribute to the discussion of whether the threshold for re-intervention in these patients should be reconsidered in order to improve long-term outcome.
The diagnosis of recurrence of coarctation is dependent on the diagnostic procedure used. An international expert committee has defined an invasively measured gradient of greater than 20 mmHg across the coarctation site in the presence of right arm hypertension to be significant. This gradient has been considered an indication for intervention.11 As mentioned above, invasive diagnostic measures have largely been replaced by non-invasive imaging modalities. Most recent guidelines of the ESC define a significant (re)coarctation as a resting arm/leg blood pressure gradient 30 mmHg and resting or exercise-induced hypertension.12 However, patients with mild residual gradients have been shown to frequently suffer from (mildly) elevated blood pressure, which is associated with an elevated cardiovascular risk. However, controlled or randomized studies are missing, registry data are limited, and local series are potentially affected by selection and reporting bias. To date, there are no data indicating that a further reduction of the gradient below any particular threshold will have clinical benefit.
In the study of Vriend et al.,8 in this issue, it has been shown that with mild residual descending aortic narrowing, but without significant residual gradient, there is a high prevalence of elevated blood pressure and carotid intima-media thickness. The results of the study suggest investigating whether a further reduction of mild residual aortic narrowing in surgically corrected coarctation patients might prevent additional organ damage and ameliorate prognosis. In view of the very good efficacy and safety of transcatheter techniques (i.e. stenting), the definition of successful treatment of aortic coarctation might need to be revised and most of such patients with mild residual aortic narrowing might be suitable candidates. However, so far there are no large multi-sited registries available collecting large data sets and long-term follow-up data of these patients in order to issue more detailed treatment recommendations, including re-intervention or pharmacotherapy only.
In view of the severe cardiovascular complications that might arise from long-standing and undertreated arterial hypertension, it becomes apparent from the study of Vriend et al.,8 that a careful follow-up for hypertension is needed in post-coarctectomy patients. A linear and continuous relationship has been shown between the severity of residual aortic narrowing and blood pressure or common carotid intima-media thickness in post-coarctectomy patients. For this purpose, the authors suggest to include 24 h blood pressure monitoring in the follow-up routine of post-coarctectomy patients, as single office blood pressure readings might not be sufficient to detect mild residual hypertension.
Future developments for congenital heart disease in adults
The number of adult patients with congenital heart disease will continue to increase, and will soon exceed the number of children with this entity. Therefore, management of co-morbidity in grown-up individuals with congenital heart disease requires close communication between the various cardiac and non-cardiac specialists involved. For the cardiology team, a thorough examination and understanding of the respective pathophysiology is required. It therefore seems important to establish a hierarchical system with dedicated specialist centres and defined referral units in order to ensure, in adult life, the continuation of the excellent level of health care provided to them during childhood. Furthermore, since many recommendations are based on well-observed clinical experiences rather than evidence-based clinical trials, there is a need for the creation of multinational registries including long-term follow-up data.
Footnotes
References
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