Between February 2006 and September 2015,
one hundred and forty-five patients (M:F=64:81,
mean age 60) affected by CTEPH underwent hemodynamic and CTPA evaluation at the Department of Cardio-Thoracic Surgery of our University Hospital.
All patients had undergone a cardiovascular examination with clinical,
functional and hemodynamic assessment (New York Heart Association class determination,
echocardiography,
Right Heart Catheterization) and a radiological evaluation through CTPA.
Finally,
cardio-surgical examination had been performed to verify eligibility criteria for PEA.
CTEPH diagnosis was based on values of Mean Pulmonary Artery Pressure (mPAP) ≥ 25 mmHg measured through RHC and on the presence of specific vascular and parenchymal signs on CTPA examination.
Of one hundred forty-five patients,
sixty-nine underwent Pulmonary Endarterectomy (PEA) and performed a clinical,
radiological and hemodynamic evaluation also after surgery.
Hemodynamic assessment considered the values of mean Pulmonary Artery Pressure (mPAP) and Pulmonary Vascular Resistance (PVR),
obtained through right heart catheterization.
Radiological evaluation included CTPA signs of pulmonary hypertension.
Radiological evaluation has been performed with an initial HRCT of Thorax performed in most with a 16-detector and in the lower part of patients with a 128-detector CT scanner; craniocaudal spiral scans were acquired,
with the patient in the supine position,
during an inspiratory breath-hold without contrast enhancement.
Scanning parameters were as follows: 120 kV ,
210 mAs,
slice thickness 0.75 mm with 0.5 mm acquisition increments,
time 11 s; the images were reconstructed using high spatial frequency (bone) algorithm and visualized with window level of −500/−700 HU and window width of 1,500/1,800 HU.
CTPA was obtained after intravenous injection (brachial anticubital vein) of 100 mL of nonionic water-soluble contrast agent,
at a rate of 4.0 ml,
followed by 40 ml of saline bolus chaser,
using a double syringe power.
Imaging was automatically started 5 s after detection of contrast enhancement in the main pulmonary artery (PA) (threshold,
80 HU) with bolus tracking.
Radiological parameters evaluated in our sample are listed in Table 1.
Pulmonary
vascular findings
|
Systemic
vascular findings
|
Cardiac findings
|
Parenchymal findings
|
TFD
Ø mPA
Ø left PA
Ø right PA
|
BAH
CC
Ø SVC
ØAV
|
Ø RA
Ø RV
Ø LV
RVFWT
ISB
Ø CS
TR
|
MP
|
|
Table.1 TFD thromboembolic filling defects, Ø mPA main pulmonary artery diameter,
BAH bronchial arteries hypertrophy,
CC collateral circles (inferior phrenic,
intercostal,
internal thoracic arteries),
Ø SVC superior vena cava diameter,
Ø AV azygos vein diameter,
Ø RA right atrium diameter,
Ø LV left ventricle diameter,
Ø RV right ventricle diameter,
RVFWT right ventricle free wall thickness,
ISB interventricular septum bowing,
Ø CS coronary sinus diameter,
TR tricuspid regurgitation,
MP mosaic perfusion.
The main pulmonary artery (mPA) diameter was measured proximal to its bifurcation,
perpendicular to the vessel wall.
Right and left ventricular short axes,
measured on a reformatted four-chamber view,
were defined as the largest distance between the interventricular septum and the free wall of ventricle.
Diameter of superior vena cava (SVC) was measured at the level of arch of azygos vein.
Tricuspid regurgitation was split in 4 grades of gravity according to the degree of contrast medium reflux into the inferior vena cava and hepatic veins [10].
In past years,
different scoring systems (modified Miller and Walsh scores and,
more recently,
Qanadli and Mastora scores) have been proposed for the quantification of clot burden with CTPA in acute pulmonary embolism [11-15].
We tried to create a new radiological CT-Score that could reflect hemodynamic changes in patients with chronic PE,
considering only radiological signs,
in particular we considered: unilateral or bilateral disease (U/B), pulmonary artery diameter (ØPA), mosaic perfusion pattern (MP) and tricuspid regurgitation (TR).
The new score was calculated as follows:
Score = U/B + ØPA + MP + TR
Scores assigned to each item are listed in Table 2.
The total score can reach a maximum value of 15.
Parameter
|
Score
|
DISEASE DISTRIBUTION
|
Unilateral=+1
|
Bilateral= +2
|
|
|
|
Ø PA
|
<2,9 cm= +0
|
≥2,9 cm and ≤3,4 cm= +1
|
≥3,5 cm and ≤3,9 cm= +2
|
≥ 4 cm= +3
|
|
MP
|
Absent= +0
|
Mild= +2
|
Moderate= +4
|
Severe= +6
|
|
TR
|
Grade 0= +0
|
Grade 1= +1
|
Grade 2= +2
|
Grade 3= +3
|
Grade 4= +4
|
|
Table 2. Score of each parameter for the New CT Score.
Radiological evaluation was made independently by two radiologists of our Department.
Discrepancies were resolved by consensus.
Hemodynamic study was performed with RHC,
the reference technique for the assessment of PH severity.
mPAP and Pulmonary Vascular Resistance (PVR) were measured through this invasive technique.
Pearson correlation was used to analyze linear associations between continuous radiological parameters and hemodynamic data for statistical analysis.
Student’s T-test was used to assess differences between pre- and post-surgical values of continuous radiological and hemodynamic parameters.
Comparisons of categorical radiological parameters were performed by Chi-square ,
McNemar Test or Wilcoxon signed-rank test.
Values of p<0.05 were considered statistically significant.
All analyses were performed with Stata/SE 12.1 Statistical Software.