Quantitative Measurement of Myocardial Perfusion by Cardiac CT in Patients
Quantitative Measurement of Myocardial Perfusion by Cardiac CT in Patients
It is a common understanding that patients with coronary heart disease are suffering, among
 others, from reduced myocardial perfusion. In order to increase (normalize) the reduced
 perfusion, when a conventional approach failed, coronary bypass surgery, coronary vessel
 dilatation or stenting are performed. The similar situation with reduced myocardial perfusion
 may be found in patients with stenosis of the aortic valve, where aortic valve replacement
 may increase myocardial perfusion by left-ventricular remodelling. However, there is
 presently no method established to measure myocardial perfusion quantitatively and
 noninvasively before and after a therapeutic intervention.

 Data of pre- and post-therapeutic myocardial perfusion, quantitatively measured in
 ml/100g/min would strengthen the indication for specific therapeutic approach and enable an
 objective control of effectiveness of the applied therapy.

 Hypothesis:

 There is a measureable difference in quantitative myocardial perfusion values before (lower)
 and after (higher) interventional or surgical procedure.

 The goal of the study is to measure myocardial perfusion by advanced CT technology (e.g. iCT
 256 Brilliance ) quantitatively in ml/100g/min in three groups of patients:

 1. Before and after coronary bypass surgery

 2. Before and after coronary vessel dilatation/stenting

 3. Before and after aortic valve replacement.

 The investigators will not assign specific interventions to the subjects of these three
 groups. Therefore, the research is strictly observational.

 Design:

 Prospective study to measure quantitatively myocardial perfusion in the above mentioned three
 groups of patients with simultaneous control and registration of all essential, physiological
 determinants of myocardial perfusion immediately prior to each CT study. The CT myocardial
 perfusion measurements will be performed directly after the indication for intervention or
 surgery and on the last day before discharge from hospital.

 All the collected data (determinants) inclusively the CT-studies will be anonymised and
 archived on a local server. The investigators of the University of Medical Computed Sciences
 and Technology, Innsbruck / Austria will perform the evaluation of the myocardial perfusion
 measurements and all statistical analysis independently of the CT-studies performing
 physicians.
Reliability of the hypothesis:

 On phantom studies simulating myocardial perfusion measurements and in animal studies we
 could confirm that using advanced CT technology (as e.g. "iCT 256 Brilliance") it is possible
 to measure myocardial perfusion in absolute values - in ml/100g/min. These myocardial
 perfusion measurements did not differ from those received by EBCT (Electron Beam Computed
 Tomography). Based on these experimental results and based on the quantitative measurements
 of myocardial perfusion in 1500 patients studied by EBCT at the Medical University of Graz
 the hypothesis may be done that using the above mentioned iCT 256 technology, it should be
 possible to measure myocardial perfusion quantitatively in a daily clinical practice.

 Ethical aspects:

 The study will be performed according to the international regulations (ISO 14144:212-01) and
 in agreement with the "Declaration of Helsinki". After oral and written explanation of the
 planned study and by signing the study agreement by patient and by responsible physician,
 patients participation is voluntary. The patients participating can leave the study any time
 without negative sequels for him or her. There is no financial restitution for the patients.

 Patients will be informed about (very rare) possible allergoid-toxic reactions during and
 after intravenous contrast agent application. For possible emergency well trained medical
 staff and equipment is present. About renal insufficiency: renal failure (creatinin clearance
 <60ml/min [GFR (Glomerulo Filtration Rate)will be calculated according the
 Cockroft-Gault-Formula, GFR {ml/min}=((40-age)*weight{kg}*0,85{only for women}]/serum
 creatinin [mg/dl]*72) above.

 The applied X-ray dose (CT) may and will be reduced by:

 reduction of KV (kilovoltage) from 120 to 100 or 80 in dependance of patients weight,
 reduction of MA (milliamper)by using iterative image reconstruction allgorithm (iDOSE). These
 technical approaches represent the best possibility to reduce X-ray dose for the patient. As
 the coronary heart disease with stenotic lesions above 50% is a disease mainly of an elderly
 men (in female mostly after menopause and in male after 50 years of age) the risk for X-Ray
 dose related genetic defects is very low. The expected applied X-Ray doses by the above
 mentioned approach will be very low and therefore the risk of X-Ray induced malignancy may be
 regarded as very low too.

 Design:

 Prospective study to measure quantitatively myocardial perfusion in the above mentioned three
 groups of patients with simultaneous control and registration of all essential, physiological
 determinants of myocardial perfusion immediately before the CT study. The CT myocardial
 perfusion measurements will be performed directly after the indication for intervention or
 surgery and on the last day before discharge from hospital.

 All the collected data (determinants) including the CT-studies will be anonymised and
 archived on a local server. These anonymised data may be approached only by members of Graz
 University of Technology, Institute of Health Care Engineering who will perform the
 evaluation of the myocardial perfusion measurements and the statistical analysis
 independently of the CT-studies performing physicians.

 Practical procedure:

 1. In supine position on CT table the blood pressure and the heart rate will be measured
 and registered.

 2. In all patients a standard native cardiac CT for evaluation of coronary calcification by
 Agatston score will be performed.

 3. In all patients myocardial perfusion will be measured in inspiration and contrast agent
 application where by the amount of contrast agent and the applied dose is related to
 patient weights as shown below:

 Patient Perfusion 210mg Iodine/ml Expected dose weight [kg] / [kV/mAs] / [ml] / per
 shoot [mSv](milli Sievert)

 <60 80/80 40 0.21/ 60-70 80/100 50 0.25/ 70-90 80/120 60 0.30/ 90-100 100/90 70 0.40/
 >100 100/100 80 0.43

 4. Standard cardiac CT will be performed to evaluate coronary arteries and left ventricular
 volumes.

 5. In supine position on CT table the blood pressure and the heart rate will be measured
 and registered.

 Quantitative evaluation:

 The calculation of the myocardial perfusion succeeds in all slices with visible left
 ventricular myocardium using a modification of the formula described by K.Miles and model
 based approaches.

 The calculation of the left ventricular volumes succeeds by use of the vendors software.

 Statistic:

 All personal and measured data will be anonymised, tested, analysed and evaluated in Graz
 University of Technology.

 The numerical values will be expressed as mean +/- SD (min, max, 95% CI). p-values of 0.05
 will be regarded statistically significant. Paired test and or Wilcoxon signed-rank tests
 will be used. X² analyses will be used to compare categoric variables. Additionally
 correlation analyses (Pearson, Spearman) will be performed and method of classification (pre-
 vs. postoperative) will be applied. All calculation will be done by SPSS 21.0 (SPSS, Chicago,
 Il, USA) or by Matlab statistic toolbox or R.

 The neccessary number of studied patients is based on the results of 64 patients studied
 before and after aortic valve replacement in whom the myocardial perfusion was measured
 before and four months after surgery.

 Pre-operative: Mean=74 (SD=21) ml/100g/min Post 4 Months: Mean=78 (SD=20) ml/100g/min.
 Difference= +4ml/100g/min. With 0.5 supposed correlation of the measured values the standard
 deviation of the differences may be estimated as 20ml/100g/min.

 By alpha=0.05, 1-beta=0.80, n=209 patients is needed.

 In addition to the pre- and post surgery evaluation, statistical models explaining the
 influence of collected data on the quantitaitve myocardial perfusion will be computed.

 As a drop-out quote of 10% may be expected it is neccessary to study in each group of
 patients 230 patients. This means total 690 patients.

 All data will be registered in database and tested for plausibility.
Inclusion Criteria:

 in cohort: Coronary Bypass Surgery:

 o presence of at least one coronary stenotic lesion above 50% with clinical indication for
 coronary bypass surgery

 in cohort: Coronary Stenting: o presence of at least one coronary stenotic lesion above 50%
 with indication for coronary vessel dilatation/stenting

 in cohort: Aortic Valve Replacement

 o presence of aortic valve disease (stenosis) with clinical indication for aortic valve
 replacement without coronary vessel stenosis above 50%

 for all three cohorts:

 -  list of medication timely related to the procedure

 -  signed informed consent

 Exclusion Criteria:

 for all three cohorts:

 -  intolerance to contrast agent

 -  multiple myeloma, pheochromocytoma, thyroid dysfunction, acute infection

 -  renal failure

 -  severe arrhythmia

 -  pregnancy

 -  reduction of cognitive capabilities to understand the purpose and the extent of the
 study

 -  participation in a medical-scientific study using X-rays in the last ten years

 -  lack of Russian knowledge to fill the forms

 -  lack of signed study agreement -