ESCR 2016 / P-0024
Certificate of Merit
Quantitative myocardial perfusion measured before and after invasive treatment using advanced CT-technology
Congress: ESCR 2016
Poster No.: P-0024
Type: Scientific Poster
Keywords: Cardiac, CT-Quantitative, Diagnostic procedure, Ischaemia / Infarction
Authors: T. Rienmüller1, C. Baumgartner1, V. Makarenko2, V. Bereznitskiy2, I. Rychina2, P. Ourednicek3, R. Rienmüller1; 1Graz/AT, 2Moscow/RU, 3Brno/CZ

Results

12 patients have been included in the study so far: 4 with indication for aortic valve replacement and 8 with indication for coronary bypass surgery. There were no patients undergoing coronary dilatation/stenting.

 

Physiological Parameters

The measured physiological parameters of the patients are listed in Tab. 1 (mean±SD (range)). We could observe an increase in heart rate (HR, see Fig. 3) and rate pressure product (RPP, see Fig. 5), and a non statistically significant decrease in systolic/diastolic blood pressure (SBP/DBP, see Fig. 4) comparing before and after surgical treatment. For the computation of RPP and SBP one patient in the bypass group after surgery had to be excluded because of missing SBP values.

 

Tab. 1: Physiological Parameters

Parameter Before Surgery

After Surgery

p-value

Heart Rate (bpm)  64.3±13.5 (50-96)

 77.5±11.7 (57-95)

 0.015

SBP (mmHg) 137.3±19.6 (110-165)

129.3±19.4 (100-170)

 0.21

DBP (mmHg)  82.3±11.6 (70-100)

 80±8.1 (68-90)

 0.7
RPP (mmHg/min) 8907±2674 (5738-15360)

9945±2416 (7000-13430)

 0.44

 

Ventricular Parameters

Tables 2, 3  and 4 illustrate the results of ventricular parameters before and after surgery. The results show that the LVMM decreases for all groups, however not statistically significant. Figure 6 shows the decrease in LVMM for each patient in the aortic valve replacement group. The end diastolic volume (EDV) and the cardiac output (CO) diminish in all groups after surgery as well. In the aortic valve replacement group statistical significance cannot be achieved primarily due to the low number of patients within this group.

 

Tab. 2: Ventricular Parameters all patients

Parameter Before Surgery After Surgery p-value
LVMM (g)  185±25 (159-243)  176±26 (135-230)  0.55
EDV (ml)  150.5±42.5 (83.4-249.3)  103.6±30.9 (54.8-155.6)  0.015
CO (l/min)  6.8±1.1 (5.3-8.8)  5.4±1.2 (3.5-7)  0.02

 

Tab. 3: Ventricular Parameters coronary bypass group

Parameter Before Surgery After Surgery p-value
LVMM (g)  169.9±8.9 (158.5-179.4)  163.5±17.1 (153.11-181.62)  0.78
EDV (ml)  148.5±18.4 (132.3-181.9)  102.7±21.9 (84.3-143.4)  0.004
CO (l/min)  6.6±0.9 (5.3-8.3)  5.4±1.1 (3.7-7)  0.02

 

Tab. 4: Ventricular Parameters aortic valve replacement group

Parameter Before Surgery After Surgery p-value
LVMM (g)  210.6±22.7 (191.9-243.38)  201.6±22.9 (174.7-229.92)  0.69
EDV (ml)  154±72.8 (83.4-249.3)  105.3±48.7 (54.8-155.6)  0.34
CO (l/min)  7.1±1.5 (5.6-8.8)  5.3±1.7 (3.5-6.8)  0.3

 

Myocardial Blood Flow (MBF)

Table 5 shows the results of estimated myocardial blood flow values before and after surgery for all patients and both patient groups separately. An average increase in MBF after surgery can be observed in all groups. In the aortic valve replacement group all individual patients and in the bypass surgery group all patients except patient 1 and 3 show an increase in MBF (see Fig. 7). In patient 3 of this group the decrease in MBF can be attributed to a decrease of the HR from 79 to 65 bpm.

 

Tab. 5: Myocardial blood flow before and after treatment

Patient group Before Surgery After Surgery p-value
All patients (n=12)
 73.1±17 (40-99)  84±12.8 (58-106)  0.09
Coronary bypass group (n=8)
 70.9±18.2 (40-94)  80±12.8 (58-97)  0.2
Aortic valve group (n=4)
 77.5±15.9 (62-99)  92±9.5 (86-106)  0.17

 

As proposed by Uren et al. 1994, the MBF value in each patient was corrected for the respective RPP by multiplying the MBF value with the average RPP of the group and dividing by the patient's individual RPP. The results of these corrected MBF values are shown in Tab. 6 and Fig. 8 and 9. Again, we can observe an increase in MBF of 10 ml/100g/min on average in all groups, however this increase is not statistically significant.

 

Tab. 6: Myocardial blood flow before and after treatment corrected by RPP

Patient group Before Surgery After Surgery p-value
All patients (n=12)
 75.2±15.2 (49-97)  85.1±11.0 (65-104)  0.16
Coronary bypass group (n=7)
 70.9±12.4 (47-90)  80±9.2 (62-90)  0.12
Aortic valve group (n=4)
 84.1±22.4 (61-104)  94± 15.8 (78-113)  0.68

 

As expected, the results of MBF show a good correlation with the heart rate. The RPP is a good indicator for myocardial oxygen consumption and shows a an excellent correlation with MBF (see Tab. 7, Fig. 10 and Fig. 11).

 

Tab. 7: Correlation coefficients with MBF

 Parameter Correlation coefficient before surgery (p-value) Correlation coefficient after surgery (p-value) Correlation coefficient total (p-value)
HR
 0.84 (<0.01)  0.54 (0.07)  0.76 (<0.01)
SBP  0.3 (0.26)  0.51 (0.1)  0.28 (0.2)
RPP  0.76 (<0.01)  0.75 (<0.01)  0.77 (<0.01)
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