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Assessment of shunt by cardiac catheterization

Our concepts of heart disease are based on the enormous reservoir of physiologic and anatomic knowledge derived from the past 70 years' of experience in the cardiac catheterization laboratory.
As Andre Cournand remarked in his Nobel lecture of December 11, 1956, the cardiac catheter was the key in the lock.
By turning this key, Cournand and his colleagues led us into a new era in the understanding of normal and disordered cardiac function in huma

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Assessment of shunt by cardiac catheterization

  1. 1. Assessment of shunt by cardiac catheterization MSN Pavan Kumar,DM,NIMS,HYDERABD
  2. 2. Shunt by cardiac catheterization Our concepts of heart disease are based on the enormous reservoir of physiologic and anatomic knowledge derived from the past 70 years of experience in the cardiac catheterization laboratory. As Andre Cournand remarked in his Nobel lecture of December 11, 1956, the cardiac catheter was the key in the lock. By turning this key, Cournand and his colleagues led us into a new era in the understanding of normal and disordered cardiac function in humans
  3. 3. Shunt by cardiac catheterization In 1930, Klein reported 11 RT heart catheterizations, including passage to the RV and measurement of cardiac output using Ficks principle. In 1932, Padillo and coworkers reported right heart catheterization and measurement of cardiac output in two subjects In 1947, Dexter reported his studies on congenital heart disease The biggest change in the last 25 years has been the return to the therapeutic potential of the cardiac catheter.
  4. 4. Shunt by cardiac catheterizationDisease Present diagnostic catheterization indicationASD , VSD , PDA For pul. resistance and reversibility Of pulmonary HTNComplex Detailed characterization of lung segmental pulmonarypulmonary atresia vascular supply when noninvasive imaging methods incompletely define pulmonary artery anatomyPA with intact IVS Determination of coronary circulationSupravalvar AS useful to define relationship to CA originsTOF Anatomy when CAs, VSDs, Ao-PA collaterals cannot be sufficiently imaged otherwiseSingle ventricle Hemodynamics/PVR
  5. 5. Shunt by cardiac catheterization 1. L – R shunt 2. R – L shunt
  6. 6. Shunt by cardiac catheterizationWhen to suspect cardiac L – R shunt ? 1. Pulmonary artery [PA] blood oxygen saturation is >80%, the possibility of a left-to-right intracardiac shunt should be considered . Plan of management by catheterisation: 1. Diagnosis 2. Quantification of shunt 3. Hemodynamic load
  7. 7. Shunt by cardiac catheterization Left-to-right Intracardiac Shunts 1. Oximetry run 2. Flow ratio 3. Indicator dye dilution technique 4. Angiography 5. Pressure mearement
  8. 8. Shunt by cardiac catheterization1. Left-to-right Intracardiac Shunts - Oximetry run In the oximetry run the oxygen content or % saturation is measured in PA,RV,RA,VC. A left-to-right shunt may be detected and localized if a significant step- up in blood oxygen saturation or content is found in one of the right heart chambers A significant step-up is defined as an increase in blood oxygen content or saturation that exceeds the normal variability that might be observed if multiple samples were drawn from that cardiac chamber.
  9. 9. Shunt by cardiac catheterization1. Left-to-right Intracardiac Shunts - Oximetry run  Various methods used for oximetry run are 1. Oxygen content 2. Oxygen saturation  Spectrophotometry  Oxygen dissociation curve  Oxygen content = O2 bound to Hb + dissolved O2  Dissolved O2 = 3.26 * PaO2 / 100.  Oxygen saturation = O2 bound to Hb / O2 capacity * 100  Oxygen capacity = Hb * 13.6
  10. 10. Shunt by cardiac catheterization1. Left-to-right Intracardiac Shunts - Oximetry run  Oxygen content  The technique of the oximetry run is based on the pioneering studies of Dexter and his associates in 1947  Oxygen content was measured by Van Slyke technique , and other manometric studies  Proposed step up at atrial , ventricular , pulmonary artery level are 2%, 1%, 0.5%.  Disadvantages of oxygen content technique  15 – 30 min for obtaining a reading  Technically difficult to perform  Dependency on Hb content
  11. 11. Shunt by cardiac catheterization1. Left-to-right Intracardiac Shunts - Oximetry run Oxygen content  Manometric to spectrophotometric method  Spectrophotometric is technically easy and results are with 1 min  Oxygen content is calculated by saturation by = O2 sat. * Hb % * 1.36  When oxygen content is derived in this manner, rather than by direct oximetric technique, the value is no more accurate (presence of carboxyhemoglobin or hemoglobin variants with O2 capacity other than 1.36).
  12. 12. Shunt by cardiac catheterization1. Left-to-right Intracardiac Shunts - Oximetry runO2 content Vs O2 saturation Antman EM. Blood oxygen measurements in the assessment of intracardiac left to right shunts: a critical appraisal of methodology. Am J Cardiol 1980 Antman and coworkers – normal variation of both oxygen content and oxygen saturation of blood in the right heart chambers Pts. without intracardiac shunts who were undergoing diagnostic cath. Oxygen content and Oxygen saturation was calculated Finally it was concluded that O2 sat. and O2 content correlate well and also proposed that systemic blood flow and mixing of blood both determine step up of O2 levels
  13. 13. Shunt by cardiac catheterization1. Left-to-right Intracardiac Shunts - Oximetry run  Oxygen saturation :  O2 is determined by 1. O2 dissociation curve 2. Spectrophotometry
  14. 14. Shunt by cardiac catheterization1. Left-to-right Intracardiac Shunts - Oximetry run  O2 saturation – O2 dissociation curve Method of saturation calculation Major disadvantage of dissociation curve is its dependency on other factors
  15. 15. Shunt by cardiac catheterization1. Left-to-right Intracardiac Shunts - Oximetry run  O2 saturation by spectrophotometry : Based on Beers law Advantages : quick ,accurate, precise , subject to few errors , less dependency on Hb% . Disadvantages :  Inaccurate if large amounts of carboxy hemoglobin is present  Indocyanin green interfere with light source of spectrphotometry  Elevated bilirubin effect absorbtion of light
  16. 16. Shunt by cardiac catheterization1. Left-to-right Intracardiac Shunts - Oximetry run  O2 saturation by spectrophotometry : Disadvantages :  1% error at 95% O2 saturation  2.5% error at 70% O2 saturation  More accurate at 40-50%  Low values O2 saturation is not at all reliable if necessary saturations below 50% can be determined by blood gas method O2 saturation spectrophotometry is presently best method for oximetry
  17. 17. Shunt by cardiac catheterization1. Left-to-right Intracardiac Shunts - Oximetry run Procedure of oximetry run  2-mL sample from each of the following locations. 1. Left and/or right pulmonary artery & Main pulmonary artery 2. Right ventricle, outflow tract, mid & tricuspid valve . 3. Right atrium, low or near tricuspid valve , mid & high . 4. Superior vena cava, low (near junction with right atrium). 5. Superior vena cava, high (near junction with innominate vein). 6. Inferior vena cava, high (just at or below diaphragm). 7. Inferior vena cava, low (at L4-L5). 8. Left ventricle. 9. Aorta (distal to insertion of ductus).
  18. 18. Shunt by cardiac catheterization1. Left-to-right Intracardiac Shunts - Oximetry run Procedure of oximetry run  In performing the oximetry run, an end-hole catheter (e.g., Swan- Ganz balloon flotation catheter) or one with side holes close to its tip (e.g., a Goodale-Lubin catheter) can be used  The entire procedure should take less than 7 minutes.  If a sample cannot be obtained from a specific site because of ventricular premature beats, that site should be skipped until the rest of the run has been completed.
  19. 19. Shunt by cardiac catheterization1. Left-to-right Intracardiac Shunts - Oximetry run site Average Range SVC 74% 67-83% IVC 78% 65-87% RA 75% 65-87% • IVC variation RV 75% 67-84% • RA variation PA 75% 67-84% LA 95% 92-98% • SVC and IVC difference LV 95% 92-98% FA 95% 92-98%
  20. 20. Shunt by cardiac catheterization1. Left-to-right Intracardiac Shunts - Oximetry run  Oxygen saturation abnormalities : Right heart saturation 1. Elevated PA saturation – high cardiac output , L to R shunt 2. Low PA saturation – low cardiac out put , low systemic arterial saturation , increased oxygen extraction . Left heart saturation 1. Elevated FA saturation – Pt.receiving O2 2. Low FA saturation – lung disease , pulmonary edema , R to L shunt
  21. 21. Shunt by cardiac catheterization1. Left-to-right Intracardiac Shunts - Oximetry run
  22. 22. Shunt by cardiac catheterization1. Left-to-right Intracardiac Shunts - Oximetry run Limitations of Oximetry Method 1. A primary source of error may be the absence of a steady state during the collection of blood samples. Error source Problem solving Prolonged because of technical Start from PCW-PA-RV-RA-VC difficulties If the patient is agitated (children) Sedation If arrhythmias occur during the Leave the site and go to next site oximetry run
  23. 23. Shunt by cardiac catheterization1. Left-to-right Intracardiac Shunts - Oximetry runLimitations of Oximetry Method2. Antman and coworkers , oxygen saturation influenced by the magnitude of systemic blood flow.  High levels of systemic flow tend to equalize the arterial and venous and low levels increase difference.
  24. 24. Shunt by cardiac catheterization1. Left-to-right Intracardiac Shunts - Oximetry run Limitations of Oximetry Method 3. Antman and colleagues , the influence of blood hemoglobin concentration may be important when blood O2 content (rather than O2 saturation) is used to detect a shunt
  25. 25. Shunt by cardiac catheterization1. Left-to-right Intracardiac Shunts - Oximetry run Limitations of Oximetry Method 4. Lacks sensitivity in detecting intracardiac shunts , Small shunts, however, are not consistently detected by this technique. 5. Variations in pulmonary venous saturation  Lower portion of lung has lower O2 saturation  Children CHD – atelectasis – compress the bronchus – desaturation of corresponding bronchus 4. d/t the presence of physiological shunt  Thebesian veins and coronary veins entering LV (R- L)  Bronchial veins draining in to LA / PV (R- L)  Bronchial artery to pulmonary artery (L – R )
  26. 26. Shunt by cardiac catheterization1. Left-to-right Intracardiac Shunts - Oximetry run 7. Various CHD where it is virtually impossible to calculate systemic and pulmonary blood flow  In a patient with a large L-R shunt caused by arterial collaterals entering the distal pulmonary vascular bed , it is impossible to obtain a blood sample distal to the shunt
  27. 27. Shunt by cardiac catheterization1. Left-to-right Intracardiac Shunts - Oximetry run
  28. 28. Shunt by cardiac catheterizationLeft-to-right Intracardiac Shunts - Indicator dye dilution technique  Indicator dye dilution technique is used to identify left to right shunt  Various dyes that are used are 1. Indocyanine green dye 2. Inhaled hydrogen , dissolved hydrogen in saline 3. Freon test 4. L – krypton – 85 5. Nitrous oxide test 6. T - 1824
  29. 29. Shunt by cardiac catheterizationLeft-to-right Intracardiac Shunts - Indicator dye dilution technique  For detection of left to right shunt dye is injected in to proximal chamber and sample is taken from distal chamber by densitometry and density of dye displayed over time  Usually it is injected in to PA and identified in aorta  Presence of L – R shunt is detected by early recirculation of dye on the down slope of the curve  In addition to identification curve can also predict the severity of shunt
  30. 30. Shunt by cardiac catheterizationLeft-to-right Intracardiac Shunts - Indicator dye dilution technique
  31. 31. Shunt by cardiac catheterizationLeft-to-right Intracardiac Shunts - Indicator dye dilution technique  In adults indocyanine green dye dilution curve provides estimate of shunt magnitude  Shunt magnitude is smaller than oxymetric method  But flow ratio (Qp/Qs) are equal in both
  32. 32. Shunt by cardiac catheterizationLeft-to-right Intracardiac Shunts - Indicator dye dilution technique Advantages :  This technique can detect left-to-right shunts too small to be detected by the oxygen step-up method .  Thus if there is no evidence of a left-to-right shunt by this method, there is no need to perform an oximetry run.  The studies of Castillo and coworkers suggest that left-to-right shunts as small as 25% of the systemic output can be detected by standard pulmonary artery to systemic artery dye curves
  33. 33. Shunt by cardiac catheterizationLeft-to-right Intracardiac Shunts - Indicator dye dilution technique Disadvantages :  Although a simple pulmonary to systemic artery indocyanine green dye curve may detect the presence of a shunt, it does not localize it  Presence of aortic and mitral regurgitation may distort the slope and give rise to false positive results
  34. 34. Shunt by cardiac catheterizationLeft-to-right Intracardiac Shunts - Angiocardiography  Selective angiography is effective in visualizing and localizing the site of left-to-right shunts  Angiographic demonstration of anatomy has become a routine part of the preoperative evaluation of patients with congenital or acquired shunts and is useful in localizing the anatomic site of the shunt
  35. 35. Shunt by cardiac catheterizationLeft-to-right Intracardiac Shunts - Angiocardiography Lesion View Angio site ASD Steep LAO (60) cranial(15) PA angio - levophase VSD LAXO(60-30) –Perimembranous and mid LV angio muscular 4CV(LAO40-40) – posterior muscular and inlet RAO(30) – Anterior muscular and outlet PDA Lateral , LAO(60) , RAO caudal Pulmonary or Aortic angio AVSD 4CV(LAO40-40) Lv angio LV – RA 4CV(LAO40-40) Lv angio
  36. 36. Shunt by cardiac catheterizationLeft-to-right Intracardiac Shunts - Angiocardiography Angiograms in the LAXO in VSD
  37. 37. Shunt by cardiac catheterizationLeft-to-right Intracardiac Shunts - Angiocardiography Angiograms in the lateral position in patent ductus arteriosus
  38. 38. Shunt by cardiac catheterizationLeft-to-right Intracardiac Shunts - Angiocardiography Angiograms in the LAO position in RSOV to RA
  39. 39. Shunt by cardiac catheterizationLeft-to-right Intracardiac Shunts - Flow ratio  Qualitative by oximetry and next Quantitative by flow ratio  Quantification is done by Qp , Qs , Qp/Qs , Effevtive blood flow, L-R shunt , R-L shunt .  Qp and Qs are amount of blood flowing through pulmonary and systemic vascular bed  Qef is quantity of mixed venous blood that carries desaturated blood from systemic capillaries to be oxygenated by lungs  L-R and R-L shunt are amount of blood that bypass systemic and pulmonary vascular bed .
  40. 40. Shunt by cardiac catheterizationLeft-to-right Intracardiac Shunts - Flow ratio  Qp , Qs , Qeff are based on Ficks principle for calculation of cariac output  Cardiac output = VO2 / AVO2 difference
  41. 41. Shunt by cardiac catheterizationLeft-to-right Intracardiac Shunts - Flow ratio  Points of importance while calculation: 1. Oxygen consumption 2. Calculation of saturations 3. Oxygen content
  42. 42. Shunt by cardiac catheterizationLeft-to-right Intracardiac Shunts - Flow ratio  Oxygen consumption:  Oxygen consumption = oxygen inspired – oxygen expired Methods for OC are the Douglass bag , the polarographic method and paramagnetic method
  43. 43. Shunt by cardiac catheterizationLeft-to-right Intracardiac Shunts - Flow ratio  Oxygen consumption:  Emperical formulas : VO2 = 125 * BSA For boys, VO2 = 138.1 - 11.49 In(age) + 0.378 (heart rate). For girls, VO2 = 138.1 - 17.04 In(age) + 0.378 (heart rate).
  44. 44. Shunt by cardiac catheterizationLeft-to-right Intracardiac Shunts - Flow ratio LaFarge C.G., Miettinen O.S. The estimation of oxygen consumption. Cardiovasc Res. 1970
  45. 45. Shunt by cardiac catheterizationLeft-to-right Intracardiac Shunts - Flow ratio  Calculation of saturation : PAO2 and FAO2 are usually calculated by blood samples MVO2 and PVO2 calculations are most important MVO2
  46. 46. Shunt by cardiac catheterizationLeft-to-right Intracardiac Shunts - Flow ratio  MVO2 at atrium level 1. At rest = 3SVC + IVC / 4 Flamms formula weights blood returning from the superior vena cava more heavily than might be expected on the basis of relative flows in the superior and inferior cavae. 2. During bicycle ergometry = SVC + 2IVC / 3 3. Directly taking SVC saturation as MVO2
  47. 47. Shunt by cardiac catheterizationLeft-to-right Intracardiac Shunts - Flow ratio  Calculation of saturation PVO2 NOT usually entered LA vs PVO2 Assumed valve if not calculated ≥ 95% FA saturation < 95% Take FA sat. 1. d/t R – L shunt assume 98% as PVO2 2. Not d/t R – L shunt take FA saturation
  48. 48. Shunt by cardiac catheterizationLeft-to-right Intracardiac Shunts - Flow ratio  Oxygen content : Oxygen in blood is present bound to Hb and dissolved content Oxygen content = O2 with Hb + O2 dissolved O2 with Hb = 13.6 * Hb in gm/dl * % saturation O2 dissolved = 3.26mlO2/L at oxygen tension of 100 mm hg Importance of dissolved oxygen – while breathing room air and breathing oxygen Eg: oxygen tension is 50 mm hg – O2 dissolved is 1.83 oxygen tension is 500 mm hg – O2dissolved is 16.3
  49. 49. Shunt by cardiac catheterizationLeft-to-right Intracardiac Shunts - Flow ratio  Additional information that can be obtained are Bidirectional shunt Double left to right shunt
  50. 50. Shunt by cardiac catheterizationLeft-to-right Intracardiac Shunts - Flow ratio  Bidirectional shunt : estimation and quantification of each L-R and R-L shunts can be done by oxymetric help in catheterisation L – R = Qp – Qeff R – L = Qs – Qeff NET SUNT = (L-R) – (R-L)
  51. 51. Shunt by cardiac catheterizationLeft-to-right Intracardiac Shunts - Flow ratio  Double left to right shunt : Not only identification but also quantification double L-R shunt can be done by oxymetry  Method 1: S = F * A – B /C – A S = L – R shunt in to the chamber F = Blood flowing in to the chamber A = O2 sat. In chamber receiving shunted blood B = O2 sat. in chamber proximal to the shunt C = O2 sat. in pulmonary vein
  52. 52. Shunt by cardiac catheterizationLeft-to-right Intracardiac Shunts - Flow ratio  Double L – R shunt Method 2 : 1. Calculate L – R shunt(Qp – Qeff) by convention 2. Calculate L – R shunt of proximal chamber assuming PAO2 to be saturation in that chamber 3. See the difference between step 1 and 2
  53. 53. Shunt by cardiac catheterizationLeft-to-right Intracardiac Shunts - Hemodynamic overload PVR = PA – PCWP / Qp SVR = AORTA – RA /Qs PVRI = PA – PCWP / CARDIAC INDEX = (PA – PCWP / Qp) * BMI PVRI/SVRI Reversibility testing when required 1. MAP > 40 mm hg 2. PVRI > 8 wood units 3. PVRI/SVRI > 0.5
  54. 54. Shunt by cardiac catheterizationSuspesion Of Right to Left Intracardiac Shunts Any patient with cyanosis or arterial desaturation <95% Supine position of the patient - Alveolar hypoventilation , Excessive sedation from the premedication COPD or other pulmonary parenchymal disease Pulmonary congestion secondary to the cardiac disease , L – R shunt Assume a more upright posture , take deep breaths , cough Administer 100% oxygen Persisting hypoxia indicates L – R cardiac shunt
  55. 55. Shunt by cardiac catheterizationDetection Of Right to Left Intracardiac Shunts Catheterisation aims in R – L shunts are 1. Detection 2. localisation 3. magnitude of shunt Various methods available in cahteterisation for R – L 1. Indicator dye dilution technique and other indicators 2. Angiography 3. Oximetry run
  56. 56. Shunt by cardiac catheterization1. Left-to-right Intracardiac Shunts - Indicators Attempts to measure right-to-left shunts in patients with cyanotic heart disease date back at least to 1941 Prinzmetal , Benenson and Hitzig studied regarding R-L identification Ether injected intravenously in patientsNormal subjects the ether is Patients with R – L shunt cause aeliminated by the lungs and prickly, burning sensation of thethus does not reach the facesystemic circulation
  57. 57. Shunt by cardiac catheterization1. Left-to-right Intracardiac Shunts - Indicators Prinzmetal then measured the time necessary for an intravenous injection of a dilute solution of saccharin to be tasted. This time is equal to the transit time from a peripheral vein through the lungs, through the left heart, and then to the systemic circulation. By increasing the concentration of the saccharin, he found that a second, much shorter appearance time occurred in patients with cyanotic heart disease because of the presence of a right-to-left shunt bypassing the pulmonary circulation.
  58. 58. Shunt by cardiac catheterization1. Left-to-right Intracardiac Shunts - Indicators He estimated the percent right-to-left shunt by the following formula: where A is the smallest concentration of saccharin to be tasted by way of the long circuit and C is the smallest concentration of saccharin to be tasted by the short circuit. But these methods are so indegenious and used now a days
  59. 59. Shunt by cardiac catheterization1. Left-to-right Intracardiac Shunts - Indicator dye dilution technique  Indicator dye dilution technique are used identify R – L shunt  Various indicators that are used are 1. Indocyanine green dye 2. Ascorbic acid 3. Hydrogen 4. Krypton – 85  Dye is injected in the right of heart proximal to presumed shunt, and detected from systemic artery  Presence and quantification of right to left shunt can be done.
  60. 60. Shunt by cardiac catheterization1. Left-to-right Intracardiac Shunts - Indicator dye dilution technique Identification
  61. 61. Shunt by cardiac catheterization1. Left-to-right Intracardiac Shunts - Indicator dye dilution technique Quantification
  62. 62. Shunt by cardiac catheterization2. Left-to-right Intracardiac Shunts - Oximetry  The site of right-to-left shunts may be localized if blood samples can be obtained from a PV , LA , LV , and Aorta  The PV blood of patients with arterial hypoxemia caused by an intracardiac right-to-left shunt is fully saturated with oxygen.  The site of a right-to-left shunt may be localized by noting which left heart chamber is the first to show desaturation .(STEP DOWN).  By calculation of Qeff quantification of total R – L can be determined by Qs – Qeff
  63. 63. Shunt by cardiac catheterization2. Left-to-right Intracardiac Shunts - Oximetry Disadvantages of oxymetry in R – L shunt: 1. The main disadvantage of this technique is that a PV and the LV must be entered. This is not as easy in adults as it is in infants, in whom the LA is entered routinely by way of the foramen ovale. 2. Quantification of desaturation that’s significant has not been adequately determined like L – R shunt.
  64. 64. Shunt by cardiac catheterization1. Left-to-right Intracardiac Shunts - Angio cardiography  Angiography helps in assessing appropriate anatomy in patients with R – L shunt. Infundibular narrowing & R-L Retrograde LV angiogram shunt into aorta is seen in the RV demonstrates a solitary malaligned VSD angio in RAO
  65. 65. Shunt by cardiac catheterization1. Left-to-right Intracardiac Shunts - Angio cardiography Right & anterior AO connected to right- sided (anterior) morphologically RV and left & posterior pulmonary artery (PA) connected to left-sided (posterior) morphologically left ventricle
  66. 66. Shunt by cardiac catheterization1. Left-to-right Intracardiac Shunts - Angio cardiography DORV with side-by-side great artery relationship and subaortic subpulmonic and doubly commited VSD
  67. 67. Thank you

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