Heart Transplant Patients Clinical Trial
Official title:
Head to Head Comparison of Multidetector Coronary Tomography and Conventional Coronary Angiogram in the Setting of Systematic Screening of Coronary Vasculopathy After Orthotopic Heart Transplantation.
Coronary vasculopathy remains the leading cause of decreased survival after the first year post-transplantation. It is mainly asymptomatic because of the denervation of the heart transplant. Currently, annual invasive coronary angiogram is performed to ensure the lack of coronary narrowing. But invasive coronary angiography caries risks of serious adverse events and some concern rise from its repetition in that population. Recent advance in coronary multidetector computed tomography (CT) may allow non invasive visualization of the coronary tree. But, it remains unknown if the encouraging data observed in native coronary artery analysis can be extrapolated to transplant heart recipients. Indeed, only very small sample size studies (20 patients) have been conducted in this particular setting. Thus, the investigators decide to assess the diagnostic accuracy of the 64-row CT and 256-row CT compared to the gold standard coronary angiogram in a larger sample size study. The practice aim of this study is to determine if the conventional invasive coronarography can be switched by the 64-row CT or the 256-row CT to assess coronary anatomy especially for the patient without any coronary artery disease (CAD) or those with CAD not suitable for percutaneous coronary intervention.
Background:
Heart transplantation is a major advance in the care of patient with terminal heart failure.
But, despite the spectacular prognosis improvement obtained with this treatment, coronary
vasculopathy remains the leading cause of decreased survival after the first year
post-transplantation (8% of death at 1 year, 42% at 5 years). This coronary artery disease
(CAD) has a particular feature involving immunological and inflammatory process, also
favoured by classical risk factors in the context of immunosuppression, with rapid and
diffuse involvement. Because of the denervation of the transplant heart, it remains mainly
asymptomatic and let non invasive stress tests with poor accuracy for CAD screening. It
explains the current use of systematic coronary angiogram to transplant heart recipient's
survey.
But coronary angiogram remains an invasive technique and exposed to potential serious
adverse events.
The recent advance in coronary multidetector computed tomography (CT) may allow non invasive
visualization of the coronary tree. Indeed, 64-row CT has already showed its accuracy for
the screening of CAD in symptomatic patient in sinus rhythm. However, they are very few
studies in the setting of heart transplantation with small sample size and mainly using
16-row CT. Only two small sample size studies (20 patients each) have been conducted using
64-row CT in the setting of heart transplant recipients. None of them compared X-Ray and
contrast iodine exposure.
Aim :
Our primary aim is to compare the diagnostic accuracy value of the 64-row CT and 256-row CT
to the gold standard (conventional coronary angiogram) in the setting of CAD screening in a
large population of heart transplant recipients (= 110 pts). We make the assumption that the
sensitivity of CT is enough to allow switching the coronary angiogram by CT for the
screening of asymptomatic CAD in heart transplant recipients without CAD or with CAD not
suitable for revascularization.
We plan also to compare X-Ray and contrast agent exposure.
Methods :
All the transplant heart patients systematically followed in the cardiovascular and thoracic
surgery service will be prospectively included. All the patients will sign the informed
consent, then CT will be performed 24 H before the coronary angiogram.
multidetector coronary computed tomography : The Electrocardiogram (ECG)-gated
contrast-enhanced multidetector computed tomography coronary angiography will be performed
with a 64 or 256-row CT Philips, Brilliance. The contrast medium (Iomeron*, ioméprol,
Bracco-Altana Pharma GmbH) mean quantity used is 80-100 ml. The CT scan parameters, adapted
to the patient's weight, include 120 kV, 800mA, 0.625 mm slice thickness, 0.42-s rotation
time and 0.2 pitch. To determine X-Ray exposure, Dose Length Product (Gycm) will be
measured.
After the scan, the reconstruction will be performed at 40 and 75 % of the cycle using ECG
gating. Additional reconstructions at different phase can be performed in case of coronary
calcification or motion artefacts.
A semi quantitative analyse (N=normal, I=intermediate, S=stenosis) of coronary narrowing
will be performed blindly to coronary angiogram results by two experienced radiologists. The
CT quality will be determined using a quality scale (scale from 1 to 5).
A Calcification score will also be determined. A segment analyse will be performed according
to AHA classification (17 segments model). Only more than 1.5 mm diameter vessel segments
will be analysed.
Coronary angiogram :
According to good practice, patients will receive 0.9 % saline serum intravenously at a dose
of 1000 ml per 12 H before and 1000 ml per 12 H after contrast medium injection.
Coronary angiogram will be performed according to standard protocol, using radial access
with 4 or 5 French sheath under continuous invasive survey of blood pressure and ECG
monitoring. The contrast medium quantity used (Hexabrix*, sodium and méglumine ioxaglate,
Guerbet) as the X-Ray dose era product (Gy.cm²) will be measured.
Quantitative coronary analysis will be performed by two experienced interventional
cardiologists blind to the CT results. Significant stenosis is defined by a > 50% vessel
narrowing.
Serum creatinine will be controlled the day before, the day after and 72 H after the
coronary angiogram.
Statistical analysis :
Comparison of the two techniques will be done by segments, by artery and by patients with
determination of the sensitivity, specificity, positive and negative predictive value of CT
for the screening of significant coronary stenosis (> 50%). Statistical analysis will be
made with Statview 5.0.
Ethical comity :
All the patient receive and sign an informed consent. The ethical comity (CPP Ile-de-France
VI) approves the protocol and the French Society of Cardiology supported the study.
Expected Calendar :
We plan to perform the CT during systematic annual hospitalisation for invasive coronary
angiogram. In the cardiovascular department, approximately 8 patients benefit from coronary
angiogram per week. Thus we plan to include 110 patients within 30 months, taking in account
the exclusion criteria and the availability of both techniques.
;
Allocation: Non-Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Single Group Assignment, Masking: Open Label, Primary Purpose: Diagnostic
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