International Journal of Cardiovascular ResearchISSN: 2324-8602

All submissions of the EM system will be redirected to Online Manuscript Submission System. Authors are requested to submit articles directly to Online Manuscript Submission System of respective journal.

Case Report, Int J Cardiovasc Res Vol: 3 Issue: 4

Multidetector Computer Tomography in Congenital Heart Disease

Claudia Pujol Salvador1, Julia Lemmer1, Farid Pouralikhan1, Michael Pörner2, Vasiliki Trigas1, Siegrun Mebus1, Stefan Martinoff2 and Harald Kaemmerer1*
1Department of Pediatric Cardiology and Congenital Heart Disease, Deutsches Herzzentrum München, Technische Universität München, München, Germany
2Institute of Radiology and Nuclear Medicine, Deutsches Herzzentrum München, Technische Universität München, München, Germany
Corresponding author : Prof. Dr. Harald Kaemmerer
Deutsches Herzzentrum München, Department of Pediatric Cardiology and Congenital Heart Disease, Deutsches Herzzentrum München, Technische Universität München, München, Germany
Phone: +49-89-1218-3011; Fax: +49-89-1218-3013
E-mail: [email protected]
Received: June 05, 2014 Accepted: July 09, 2014 Published: August 04, 2014
Citation: Salvador CP, Lemmer J, Pouralikhan F, Pörner M, Trigas V, et al. (2014) Multidetector Computer Tomography in Congenital Heart Disease. Int J Cardiovasc Res 3:4. doi:10.4172/2324-8602.1000175

Abstract

Multidetector Computer Tomography in Congenital Heart Disease

Objectives: Extracardiac pathology is common in patients with congenital heart disease. Multidetector computer tomography can be a useful tool for detection. To date, there are only scarce reports regarding “incidental“ non-cardiac findings during cardiac computer tomography. Aims of this study were to analyze indications, implementation, and timing of multidetector computer tomography in patients with congenital heart disease. Materials and methods: During 32 months, 195 patients were retrospectively included in our analysis. Type of congenital heart disease, timing of the procedure (preoperative, postoperative, follow-up, native), explored areas (thorax, cranium, abdomen, sternum, neck and extremities), and indications were disclosed. Results: During the study period, 250 scans were performed in 195 patients. Mean age was 23.0 ± 17.1 years (minimum 3 days, maximum 73 years); 48.2% were younger than 20 years. Almost 71% had undergone reparative cardiovascular surgery. Complex congenital heart disease (26.5%) and left-ventricular heart obstructions (22.5%) were the most common defects referred to computer tomography. In 19.5% of patients more than one scan was necessary. The tests were most performed in the postoperative/ postinterventional (36%) and long-term follow-up (30.4%) periods. Most indications focused on the thorax (55.5%), particularly when cardiovascular complications were suspected. Assessment of cerebral pathology was the second most frequent indication (25%). Final diagnosis was achieved in 94% of cases. Conclusions: Extracardiac pathology is frequent in patients with congenital heart disease, mainly in younger patients and with complex cardiac pathology. Multidetector computer tomography is a very useful tool when cardiovascular complications or cerebral pathology is suspected. Therefore, a good cooperation between radiologists and congenital cardiologists is mandatory.

Keywords: Multidetector computer tomography; Congenital heart disease; Extracardiac pathology

Keywords

Multidetector computer tomography; Congenital heart disease, Extracardiac pathology

Introduction

Congenital heart diseases (CHD) are the most common types of birth defects. The overall incidence is about 75/1,000 live births. For the moderate and severe forms, the incidence of CHD is about 6/1,000 live births [1]. Advances in medical and surgical care have improved the survival of these patients [2]. At present, more than 80-85% of patients reach adulthood [3]. It is estimated that there are about 2,800 CHD-adults per 1 million populations, with more than half of them having moderate or high complexity defects [2]. Because of complications, previous corrective surgery, and palliative surgery, up to 75% of these patients will require life-long follow-up [2,3].
Cardiac imaging is the cornerstone for the diagnosis, pre- and postoperative evaluation and follow-up of patients with CHD. Besides echocardiography and cardiac catheterization, magnetic resonance imaging (MRI) and computer tomography (CT) are gaining importance. These techniques do not depend on acoustic windows. permit the depiction of extracardiac structures and 3D reconstruction [4].
Multidetector computer tomography (MDCT) provides great resolution imaging [5]. Sedation is not needed as the images are taken in very short time, which makes it especially indicated in young children [4]. Furthermore, it is feasible in patients with pacemakers, mechanical prosthesis, metallic conduits and coils, while MRI is contraindicated in those cases or shows metallic artifact [6].
In general cardiology, it is particularly useful for the study of coronary artery disease [5]. Non cardiac findings have been reported in 15% to 67% of cases during coronary MDCT in adult population, with different clinical relevance [5,7]. Many of extracardiac pathologies concentrate in the pulmonary region. Hunold et al. [8] reported 29% pulmonary disease, of which 1.1% was suspected tumors.
MDCT provides excellent representation of cardiovascular anatomic structures in patients with CHD [9,10]. It enables to assess systemic and pulmonary circulation, coronary artery blood flow, collateral circulation and shunt status [6,11]. On the other hand, CHD patients also suffer from extracardiac pathologies that can require MDCT.
The purpose of this study was to investigate the role of MDCT in patients with CHD, and to highlight the importance of cooperation between radiologists and cardiologists. It provides useful information regarding the frequency and type of CHD that require MDCT, the regions of interest and most common indications. It also informs about technical information such as need of contrast medium and number of procedures required to achieve a final diagnosis.

Materials and Methods

Study design
We retrospectively analyzed 195 consecutive patients who underwent MDCT in our institution. MDCT was indicated according to clinical symptoms, when other imaging techniques were insufficient to achieve diagnosis or were contraindicated (for example, MRI and pacemaker). Patients with contrast medium allergy, orthopnoea and renal failure were excluded. Informed consent was mandatory.
Patients with CHD were classified into native (not surgically treated), after reparative or palliative surgery, and interventionally treated. The number of surgical or interventional procedures was noted. The type of CHD was divided into 8 groups: complex heart anomalies (like transposition of the great arteries, truncus arteriosus communis; groups 1-3), outflow tract obstructions (right or left sided; groups 4-5), shunts (pretricuspid, posttricuspid; groups 6-7) and others (group 8).
Timing of MDCT (native, preoperative, postoperative, long-term follow-up) and indications were taken into consideration.
The explored anatomic regions were divided into 6 groups: thorax, cranium, abdomen, sternum, neck and extremities. The need of contrast medium was also noticed.
Technical considerations
MDCT was performed with the patient in supine position, using a 128-slices CT (Dual-Source CT, SOMATOM Definition, Siemens AG, Forchheim, Germany). Iomeprol (Imeron®, Altana, Konstanz, Germany) was used as contrast medium whenever necessary. Application- and flow-rate were adjusted according to patient’s age and weight. Contrast was injected either by hand or with a syringe pump (Injektron CT2, Medtron, Saarbrücken, Germany). After contrast administration, an isotonic sodium chloride solution (Delta Select®, Delta Select GmbH, Pfullingen, Germany) was given to flush. Prospective ECG-triggering was used to reduce X-ray time. For optimal imaging quality, a goal heart rate of 65 bpm was targeted by using Beta-blockers (bisoprolol) when necessary.
The images were interpreted and post processed on a workstation. Axial source, multiplanar reconstruction, maximum intensity projection, and volume-rendered images were used for the assessment. The images were analyzed by a radiologist and a pediatric cardiologist with training in radiology for more than 5 years.
Statistical analysis
Data are presented numerically, as percentages or as means ± standard deviation (SD). Data were processed using SPSS 15.0 (SPSS Inc, Chicago, IL).

Results

During a study period of 32 months, 195 patients (111 men and 84 women) underwent 250 MDCT. Mean age was 23.0 ± 17.1 years (minimum 3 days, maximum 73 years); 48.2% were younger than 20 years (Figure 1).
Figure 1: Distribution of MDCT according to age and gender.
Up to 31 (15.9%) patients had a native CHD. In 138 (70.8%) patients had prior reparative surgery, 13 (6.7%) patients had prior palliative surgery and 13 (6.7%) patients had previously undergone an interventional procedure. The number of surgeries was: one in 61 (31.3%) patients, two in 34 (17.4%), three in 25 (12.8%), four in 18 (9.2%), five in 11 (5.6%) and six or more in 15 (7.7%) patients.
Patients were classified into 8 diagnostic groups: complex CHD (groups 1-3) (51 patients, 25.6%), left heart obstruction (group 4) 44 patients (22.5%), right heart obstruction (group 5) 36 patients (18.4%), post-tricuspid shunts (group 6) 22 patients (11.3%), pretricuspid shunts (group 7) 18 patients (9.2%) and other types of CHD (group 8) 24 patients (12.3%). The results are shown in Table 1.
Table 1: Diagnostic subgroups and number of patients included.
The number of examinations (or explorations) required was: one MDCT in 157 (80.5%) patients, two scans in 29 (14.9%) patients, three in four (2.1%) patients, four in two (1.0%) patients and five in three (1.5%) patients.
Timing of MDCT is presented in Figure 2. Postoperative/ postinterventional time was the most frequent time for MDCT (90 tests, 36%), followed by long-term follow-up (76 tests, 30.4%). The least frequent were preinterventional/preoperative (49 tests, 19.6%) and native CHD (35 tests, 14%).
Figure 2: Timing and demands of MDCT-studies in the course of the congenital heart anomaly.
Thorax was the most explored region (n= 172, 55.5%), followed by cranium (n= 72; 23.2%), abdomen (n= 44; 14.2%), sternum (n= 13; 4.2%), neck (n= 6; 1.9%) and extremities (n=3; 1.0%).
Most indications concentrated in diagnosis of extracardiac pathology or assessment of complications. The most common were: cerebral vascular disease (26.6%), pulmonary thromboembolism (19.3%), pathology around sternotomy (8%), aortic complications (aneurysm or dissection, 14.6%), inflammation/infection (18%), choanal atresia (2%), haemoptysis (2.6%), vascular anomalies (2%) and others (6.7%). A final diagnosis was achieved in 94% of cases.
Intravenous contrast medium was used in 208 (83.2%) scans. Four patients required oral contrast medium as well, and in one patient it was also administrated through a cutaneous fistula. No allergic reactions were reported.

Discussion

This study shows the importance of MDCT in about half of CHD patients for the diagnosis and assessment of extracardiac pathology, such as pulmonary thromboembolism or cerebral vascular disease. More than half of indications concentrate in the thoracic region. Immediate postoperative/post interventional period and long-term follow-up are the most frequent times of MDCT. Contrast medium is required in most cases and no adverse reactions have been reported. MDCT is therefore a safe technique.
Besides cardiac illness, this study shows that patients with CHD present frequently with associated extracardiac pathology. Earlier reports focused on the anatomical depiction of CHD and informed about extracardiac lesions as incidental diagnosis. In this regard, Bayraktutan reported 26% of extracardiovascular lesions in a cohort of 105 patients with CHD. The most common diagnosis was pneumonia and pulmonary edema [6]. Since non-invasive techniques provide great anatomical and functional accuracy, their use has increased in the last decades. Prakash et al. pointed out that these techniques are growing while diagnostic catheterisation decreases. On the other side, interventional catheterization shows a steady increase and surgery increases modestly [12].
The study presented here shows that most common indications concentrated in thoracic area, in order to diagnose/exclude vascular complications (suspected pulmonary embolism, aneurysm/ dissection, vascular anomalies, and hemoptysis). Another nonnegligible indication was the assessment of cerebral complications in 26.6%. Inflammation was the third indication for MDCT (18% in our series).
On the other side, the most frequent timing for MDCT was the immediate cardiac postoperative period (36%). That is probably why more than 50% of the tests were performed in the thoracic area. Regarding cerebral pathology, Wolman et al. [13] described 15.8% of cerebral complications after cardiac surgery, especially due to embolization. Moderate to severe atherosclerosis increased five-fold the risk of having a cerebral event [13].
MDCT has several advantages. First of all, it permits to acquire high-definition images in a very short time. Furthermore, it allows defining vascular structures of 1-2 mm [14]. In cardiology, MDCT is the non-invasive method of choice for the evaluation of coronary anomalies and coronary artery disease [15,16]. Some studies pointed out that MDCT is also valid for the study of shunt-size, location and flow direction [14]. It is a method of choice in patients with metallic devices and pacemakers [14]. MDCT also allows the analyses of cardiac dimensions and function [17,18], with less definition for segmental contraction compared to MRI. Function of prosthetic valves can also be assessed [18].
However, MDCT has some disadvantages. The most important S radiation and use of contrast medium. This is especially of importance in patients with CHD, who need to undergo frequent imaging and interventions in their lifetime. In this study, almost 20% of patients underwent 2 or more procedures.
Regarding radiation damage, a dose of 1 mSv per year leads to a lifetime probability of fatal cancer of 4–5 new cases among 100,000 patients exposed. Hoffman et al. [19] analysed, in the multicentric study “European Heart Survey on adult congenital heart disease”, the cumulative radiation dose in patients with CHD. The average cumulative effective dose per patient was 0.46 mSv. CT-scans contributed to radiation exposure in 39%, being the second source of radiation behind angiography. Patients with higher radiation were those who more often needed controls of the aorta, like coarctation of the aorta and Marfan syndrome [19]. Taking into account that almost half of the patients of this study were younger than 20 years, optimization of the procedure (like ECG trigger) and the lowest required radiation should be used. Recent innovations (ultra-highpitch, very large detectors, advanced reconstruction algorithms, and the step-and-shoot models) [20] permit to get lower radiation doses with a good “signal-to-noise ratio”.
The results of this study show that MDCT should be available in tertiary centers with a department for CHD. Because of the frequent non cardiac manifestations of patients with CHD on MDCT, a strong cooperation between congenital cardiologists and radiologists is mandatory. While congenital cardiologists focus on cardiac anatomy [21], radiologists provide a meaningful overview of extracardiac structures. Radiologists should also have a background in CHD in order to avoid misdiagnoses.

Limitations

This study has several limitations that must be taken into account. First of all, it should be interpreted in light of the limitations imposed by the retrospective and descriptive nature of the study design; hence, selection of the study patients was not random. Direct comparison or validation with other techniques such as MRI or cardiac catheterization was not performed. Nevertheless, it is our opinion that the CT represents the gold standard technique in several scenarios. Furthermore, most indications for MDCT were based on clinical findings. We cannot exclude extracardiac diagnosis in asymptomatic patients.

Conclusion

Extracardiac pathology is frequent in patients with CHD, especially in younger patients and with complex cardiac pathology. Hence, MDCT is a fundamental tool when suspecting vascular complications or cerebral pathology and should be available in all tertiary centers with a department of congenital heart disease.
Because extracardiac findings are frequent in CHD, a strong cooperation between radiologists and congenital cardiologists is mandatory.

Acknowledgments

Claudia Pujol received a grant of the Spanish Society of Cardiology for investigation in foreign countries.

References






















Track Your Manuscript

Scheduled supplementary issues

View More »

Media Partners