In this ppt i am going to discuss how to do cardiac catheterisation study, oximetry study and how to analyse its data in a patient with VSD who came to our hospital

1. 1
CATH
MEET
UNIT IAA
Presenter-Praveen Gupta
28-01-2017
Cath Study in
a patient with
VSD

2. History
 A 40 year old female resident of Bankura, West Bengal came to JIPMER
hospital cardiology OPD with chief complaints of
 Dypnoea on exertion NYHA Class III since 2 month
 Chest pain since last one month
2

3. On examination
 Cyanosis+/Clubbing +/Icterus-/LAP-
 Pulse- 71 beats per min
 BP-110/70 mmhg
 CVS-S1S2 + S2 Loud
 RS-Bilateral NVBS+
 SPO2-90%
3

4. Investigation
 Hb-15.5
 Platelet count 1.5 lacs
 RBS-74
 BUN-33
 S.Creatinine-1.4
 Uric acid-2.5
 HIV-NR
 HBsAg-NR
 Anti HCV- Negative
 Body weight-37 kgs
 Height-144 cms
4

5. Investigation
 ECG-Normal sinus rhythm at 60 beats per minute, right axis deivation,
right ventricular hypertrophy
 Echocardiography Large muscular VSD with bidirectional shunt was
present, Severe tricuspid regurgitaion with RVSP 130 mmhg, IAS was
intact, no PDA, CoA, Normal biventricular function
5

6. Course in the hospital
 VSD with Severe pulmonary hypertension
 Planned for cardiac catheterization to look for feasbility for surgical repair.
 But cardiac catheterization was not possible in view of logistic reason so
patient was discharged and advised to follow up in cardiology OPD.
 Patient was started on tablet Sildenafil 25 mg TDS
 Patient again visited JIPMER after six month
 During this admission her Spo2 was 95%, and she was found to be HCV
positive
 So cath study was planned
6

7. Cath study (Oximetery run )
Pre-oxygenation Post oxygentaion (100%
O2)
SVC 58.8% 70.8%
IVC 74.9% 75.9%
Right atrium 62% 84%
Right ventricle 77.3% 91.1%
Pulmonary artery 87.4% 91.2%
Pulmonary vein 92.7% 98.3%
Left atrium 88.1% 96%
Left ventricle 96% 99.3%
Aorta 92.1% 94.5%
Mixed venous oxygen
satuation
62.82% 72.07
7

8. Saturation pre-oxygenation
62.0
%
77.3
%
58.8%
96 %
87.4
%
92.1
% 88.1
%
74.9 %
92.7
%
8

9. Saturation postoxygenation
84.0
%
91.1
%
70.8%
99.3
%
91.2
%
94.5
% 96 %
75.9 %
98.3
%
9

10. Pressure in various cardiac chamber during cath
study(Post-oxygenation)
Systolic pressure
(mmhg)
Diastolic pressure
(mmhg)
Mean
Pressure(mmhg)
Right atrium 6
Left atrium 6
Pulmonary artery 88 40 62
Aorta 98 67 77
10

11. Oxygen content calculation
Chamber Oxygen content calculation Oxygen
content
SVC 0.136X10X70.8+0.03X63 98.17
IVC 0.136 X 10 X 75.9 + 0.03 X 52 104.784
Pul Artery 0.136 x 10 x91.2 + 0.03 x 132 127.992
Pul venous 0.136 X 10 X 98.3 + 0.03 X 450 147.188
Aorta 0.136 x 10 x 94.5 + 0.03 x 40.4 140.64
Mixed
venous
oxyg
saturation
3 x SCV + 1 X IVC/ 4 99.82
11

12. Cath study data
BSA 1.22 m2
Vmax 150 x BSA 184.37
Qs(Systemic blood
flow)
Vmax/Ao2-MVo2 4.51
Qp(Pulmonary
blood flow)
Vmax/Pvo2-Pao2 9.60
Qp/QS 9.60/4.51 2.12
EBF(Effective
blood flow)
Vmax/Pvo2-MVo2 4.091
12

13. Cath study data
PVR Pa(mean)-LA(mean)/Qp 62-6/9.60 5.88 wood unit
SVR Ao(mean)-RA(mean)/Qs 77-6/4.51 15.63 wood unit
PVR/SVR 5.88/12.41 0.3761
L-R Shunt PBF-EBF 9.60-4.091 5.509
R-L Shunt SBF-EBF 4.51-4.091 0.419
13

14. Conclusion
 VSD/Severe PAH/Bidirectional shunt/moderate pulmonary vascular
resistance
 Plan-Medical management with intracardiac repair for VSD
14

15. Shunt Determinations
 Normally, PBF and SBF are equal
 With abnormal communication between intracardiac chambers or great vessels, blood flow is
shunted from the systemic circulation to the pulmonary circulation (left-to-right shunt), from
the pulmonary circulation to the systemic circulation (right-to-left shunt), or in both
directions (bidirectional shunt).
 Most commonly method for shunt determination, oximetric method
 Unexplained pulmonary artery oxygen saturation > 80% raise suspicion for left-to-right shunt
 Unexplained arterial desaturation (<93%) indicate a right-to-left shunt
 If arterial desaturation persists after the patient takes several deep breaths or after
administration of 100% oxygen, a right-to-left shunt is likely
15

16. Oximetric Method
 The oximetric method is based on blood sampling from various cardiac chambers for
determination of oxygen saturation
 Left-to-right shunt is detected when a significant increase in blood oxygen saturation is found
between two right-sided vessels or chambers
 Obtains blood samples from all right-sided locations
 A full saturation run obtains samples from the high and low IVC; high and low SVC; high,
middle, and low right atrium; RV inflow and outflow tracts and midcavity; main pulmonary
artery; left or right pulmonary artery; pulmonary vein and left atrium, if possible; left
ventricle; and distal aorta
16

17. Shunt Quantification
 To determine left to- right shunt, PBF and
SBF required
 Principles of Fick cardiac output are used
to quantify intracardiac shunts
 PBF is oxygen consumption/ difference in
oxygen content across pulmonary bed
 SBF is oxygen consumption/difference in
oxygen content across the systemic bed
 Effective blood flow (EBF) is the fraction
of mixed venous return received by the
lungs without contamination by shunt flow
 In the absence of a shunt, PBF, SBF, and
EBF are all equal
17

18. Shunt Quantification
where PvO2, PaO2, SaO2, and MvO2 are the oxygen content (in milliliters of
oxygen per liter of blood) of pulmonary venous, pulmonary arterial, systemic
arterial, and mixed venous blood, respectively
18

19. Shunt Quantification
 The mixed venous oxygen content is the average oxygen content of blood in the
chamber proximal to the shunt.
 When assessing a left-to-right shunt at the level of the right atrium, one must
calculate the mixed venous oxygen content on the basis of the contributing blood
flow from the IVC, SVC, and coronary sinus.
 The most commonly used method is the Flamm formula
19

20. Shunt Quantification
 Assuming conservation of mass, the size of a left-to-right shunt, when no associated right-to-
left shunt is present, is simply
LR shunt = PBF − SBF
 When there is evidence of a right-to-left shunt in addition to a left to- right shunt (also
referred to as a bidirectional shunt), the approximate size of the left-to-right shunt is
LR shunt = PBF − EBF
 Approximate size of the right-to-left shunt is
RL shunt = SBF − EBF
20

21. Shunt Quantification
 Flow ratio PBF/SBF (or Qp/Qs) is used clinically to determine the significance of the shunt
 Ratio of less than 1.5 indicates a small left-to-right shunt
 Ratio of 1.5 to 2.0, a moderate-sized shunt
 Ratio of 2.0 or higher indicates a large left-to-right shunt
 A flow ratio of less than 1.0 indicates a net right-to-left shunt
21

22. Various formula used are---
 A-VO2 is the arterial-venous oxygen saturation
difference
 Hgb is the hemoglobin concentration (mg/dL),
and the constant 1.36 is the oxygen-carrying
capacity of hemoglobin (expressed in mL O2/g
Hgb)
 Systemic vascular resistance (SVR) in absolute
units is calculated with the following equation:
 Aom and RAm are the mean pressure (in mm Hg)
in the aorta and right atrium, respectively, and Qs
is systemic cardiac output (in liters/min).
 The constant 80 is used to convert units from mm
Hg/liter/ min (Wood units) to the absolute
resistance units dyne-sec • cm−5
22

23. Various formula used are---
 where PAm and LAm are mean pulmonary
artery and left atrial pressure, respectively, and
Qp is PBF.
 If mean left atrial pressure has not been
measured directly, mean pulmonary capillary
wedge pressure is commonly substituted for it,
although errors can occur because of this
substitution.
 In the absence of an intracardiac shunt, Qp is
equal to systemic cardiac output.
 PVR describes the pressure across the major
pulmonary vessels and the precapillary
arterioles and pulmonary
23

24. 24

25. Operative criteria in a patient with intracardia shunt
25

26. Operative criteria
26
 The use of a PVR of 6 Wood units m2 and a PVR∶SVR ratio of 0.3 as limits for considering
operation in PAH-CHD was proposed in a previously published consensus
 20% decrease in PVR from baseline during the acute vasodilator test was considered
sufficient to define a positive response but not to characterize operability
 More recently, during the 5th World Symposium on Pulmonary Hypertension of the World
Health Organization (Nice, France, February 2013), a PVR of 4 Wood units m2 was proposed
as a limit for considering surgery, and a PVR of 4–8 Wood units m2 as the range in which
patients should be discussed case by case.

27. Operative criteria
27
 The Pediatric Task Force also concluded that at present, there is no
established protocol for the vasodilator test in children and no evidence to
use it for prognostic purposes.
 There has been debate about what to do with patients with elevated PVR
(e.g., PVR > 8–10 Wood units m2and PVR∶SVR > 0.5), in particular since
the answer will not be the same for patients at different ages

28. 28