IABP

Intra-aortic balloon counterpulsation is an important supportive tool to the failing heart as a bridge to tide over a temporary crisis.

1. IABP INTRA-AORTIC BALLOON COUNTERPULSATION Dr. VISHAL VANANI Jaslok Hospital and Research Centre April 2015

2. HISTORY Kantrowitz  described augmentation of coronary blood flow by retardation of the arterial pressure pulse in animal models in 1952 . In 1958, Harken  suggested the removal of some of the blood volume via the femoral artery during systole and replacing it rapidly in diastole as a treatment for left ventricular (LV) failure, so called diastolic augmentation.

3. HISTORY In the 1960s , Moulopoulos and colleagues  from the Cleveland Clinic developed an experimental prototype of an IABP whose inflation and deflation were timed to the cardiac cycle. In 1968, Kantrowitz reported improved systemic arterial pressure and urine output with the use of an IABP in two subjects with cardiogenic shock, one of who survived to hospital discharge.

4. HISTORY Balloon catheters were 15 French and needed to be surgically grafted into the femoral arteries. Percutaneous IABs in sizes 8.5-9.5 French (rather than 15 French used earlier) were introduced in 1979, and shortly after this, Bergman and colleagues described the first percutaneous insertion of IABP. The first prefolded IAB was developed in 1986 .

5. CARDIAC PHYSIOLOGY

6. PRELOAD Preload refers to the amount of stretch on the ventricular myocardium prior to contraction . Starling’s law described how an increase of volume in the ventricle at the end of diastole resulted in an increase in the volume of blood pumped out. Preload is often referred to as “filling pressure ”. Factors affecting preload include: Aortic insufficiency Circulating blood volume Mitral valve disease Some medications (i.e. Vasoconstrictors, vasodilators)

7. AFTERLOAD Afterload is the resistance that the heart must overcome in order to eject the blood volume from the left ventricle Afterload takes several forms: The mass of blood that must be moved, measured by the hematocrit Aortic end diastolic pressure (AEDP). Arteriole resistance Afterload can be affected by: Aortic stenosis Arterial vasoconstrictors and vasodilators Hypertension Peripheral arterial constriction

8. OXYGEN CONSUMPTION Myocardial Oxygen Consumption Depends on Systolic wall stress Intra-ventricular pressure Afterload End diastolic volume Wall thickness

9. HOW IABP HELPS?

10. IABP – HOW IT WORKS A flexibile catheter – into the descending aorta. Correct positioning – Important When inflated, the balloon blocks 85-90% of the aorta . This balloon displaces the blood that is in the aorta. This is known as counter pulsation This sudden inflation moves blood superiorly and inferiorly to the balloon. When the balloon is suddenly deflated, the pressure within the aorta drops quickly.

11. WHY HELIUM? Helium: Low Density Soluble

12. IABP – HOW IT HELPS Inflation of the balloon occurs at the onset of diastole. At that point, maximum aortic blood volume is available for displacement because the left ventricle has just finished contracting and is beginning to relax, and the aortic valve is closed. The pressure wave that is created by inflation forces blood superiorly into the coronary arteries. This helps perfuse the heart. Blood is also forced inferiorly increasing perfusion to distal organs (brain, kidneys, tissues, etc.)

13. IAB INFLATION Balloon inflated during diastole Increasing aortic pressure and Increasing coronary blood flow Increases Myocardial O2 delivery

14. IAB DEFLATED The balloon remains inflated throughout diastole. At the onset of systole, the balloon is rapidly deflated. The sudden loss of aortic pressure caused by the deflation reduces afterload. The left ventricle does not have to generate as much pressure to achieve ejection since the blood has been forced from the aorta. This lower ejection pressure reduces the amount of work the heart has to do resulting in lower myocardial oxygen demand.

15. Hemodynamic Effects of IABP Aorta ↓ systolic pressure, ↑ diastolic pressure Left ventricle ↓ systolic pressure, ↓ end-diastolic pressure , ↓ volume , ↓ wall tension Heart ↓ Afterload, ↑ Cardiac Output, ↓ O2 Demand Blood flow ↑ coronary blood flow

16. HEMODYNAMICS : Summary Afterload Myocardial oxygen demand Coronary flow Cardiac output

17. INDICATIONS Refractory unstable angina Persistent myocardial ischemia ( preop or postop) Acute myocardial infarction Complications of acute MI Cardiogenic shock Refractory LV failure Acute MR and VSD Support for high-risk catheterization or failed PCI Refractory ventricular arrhythmias As a bridge to cardiac transplantation Support during transport Preoperative IABP (high-risk patients) Cardiac surgery, High risk CABG Weaning from cardiopulmonary bypass Postcardiotomy LV systolic failure unresponsive to inotropes

18. CONTRAINDICATIONS Severe aortic insufficiency Dissecting aortic aneurysm Descending thoracic aortic atheroma Aorto -iliac-femoral occlusive disease Lower extremity ischemia Dynamic LVOTO Chronic end-stage heart disease with no anticipation of recovery Aortic stents End-stage cardiomyopathies Severe atherosclerosis End stage terminal disease Abdominal aortic aneurysm Uncontrolled sepsis Severe peripheral vascular disease Major arterial reconstruction surgery Blood dyscrasias (Thrombocytopenia )

19. COMPLICATIONS Transient loss of peripheral pulse Limb ischaemia Thromboembolism Compartment syndrome Retroperitoneal hematoma Local vascular injury—false aneurysm, haematoma , bleeding from the wound Aortic perforation and/or dissection Cardiac tamponade Thrombocytopenia Infection / sepsis Malpositioning causing cerebral or renal compromise Renal failure and bowel ischemia Heparin induced thrombocytopenia Balloon rupture (can cause gas embolus) Balloon entrapment

20. HOW TO INTRODUCE

21. IABP Kit Contents Introducer needle Guide wire Vessel dilators Sheath IABP (34 or 40cc) Gas tubing 60-mL syringe Three-way stopcock Arterial pressure tubing (not in kit )

22. IAB Sizing Chart

23. INSERTION TECHNIQUE Percutaneous S heath less With Sheath Surgical insertion Femoral cut down Trans-thoracic

24. The IABP device has two major components: A double-lumen 8.0-9.5 French catheter with a 25-50 ml balloon attached at its distal end; and A console with a pump to drive the balloon. The balloon is made of polyethylene and is inflated with gas driven by the pump.

25. POSITIONING The end of the balloon should be just distal to the takeoff of the left subclavian artery Position should be confirmed by fluoroscopy or chest x-ray

26. HOW TO ADJUST IABP

27. OPERATION MODE

28. OPERATION MODES Automatic Tracks cardiac cycle, cardiac rhythm and adjusts automatically Semiautomatic Operator must adjust inflation & deflation Manual Operator must adjust inflation & deflation & can set fixed rate

29. TRIGGER SOURCE During a cardiac arrest, the IABP can provide very effective perfusion in conjunction with external compressions. Since there is no ECG signal and no arterial pressure wave to trigger the pump, an internal trigger is selected. This trigger detects the flow of blood caused by compressions and inflates the balloon providing improved circulation. Good, consistent compressions are a must for this to work!

30. IAB FREQUENCY

31. AUGMENTATION

32. TIMINGS

33. TIMING OF COUNTER PULSATION UASBP UASBP ADBP UADBP UADBP ASBP DABP

34. INTRAAORTIC BALLOON COUNTERPULSATION Timing of inflation : First identify the dicrotic notch (when the aortic valve closes ) If inflation is too early the balloon inflates before the aortic valve closes and pumps blood backwards into the LV, and ↑ LVEDV & LVEDP, Increased left ventricular wall stress or afterload, Aortic regurgitation, Increased MV02 demand. If inflation is too late there will be sup-optimal coronary perfusion

35. INTRAAORTIC BALLOON COUNTERPULSATION Early inflation :

36. INTRAAORTIC BALLOON COUNTERPULSATION Late inflation :

37. INTRAAORTIC BALLOON COUNTERPULSATION Timing of deflation: If deflation is too early there will be inadequate afterload reduction and sub-optimal coronary perfusion If deflation is too late the balloon remains inflated too long, causing ↑ afterload because the heart is trying to pump against an inflated balloon

38. INTRAAORTIC BALLOON COUNTERPULSATION Early deflation:

39. EARLY DEFLATION Waveform Characteristics: Assisted aortic end diastolic pressure may be ≤ the unassisted aortic end diastolic pressure. Assisted systolic pressure may rise. Physiologic Effects: Sub-optimal coronary perfusion. Potential for retrograde coronary and carotid blood flow. Sub-optimal after load reduction & Increased MV02 demand.

40. INTRAAORTIC BALLOON COUNTERPULSATION Late deflation:

41. LATE DEFLATION Waveform Characteristics: Assisted aortic end diastolic pressure may be equal to the unassisted aortic end diastolic pressure. Rate of rise of assisted systole is prolonged. Diastolic augmentation may appear widened. Physiologic Effects: Afterload reduction is essentially absent. Increased MV02 consumption due to T he left ventricle ejecting against a greater resistance IAB may impede left ventricular ejection and increase the afterload

42. MAINTENANCE CARE Ankle flexion and extension one to two hourly Use pressure relieving mattress Change ECG electrodes daily. Change occlusive dressing daily Secure balloon catheter at several points along the limb .

43. OBSERVATIONS Observe hourly at catheter insertion site For signs of bleeding Signs of infection Signs of blood in sheath If blood or brown dust is observed within the lumen, immediately place the IABP on 'Standby '. The catheter will have to be removed immediately .

44. OBSERVATIONS Check hourly for left radial pulse Put SaO2 probe on left hand Assess the limb distal to the insertion One hourly Observe and record peripheral pulses, capillary refill, skin, temperature Observe the waveform to ascertain that the timing is correct

45. WEANING of IABP Timing of weaning Patient should be stable for 24-48 hours Decreasing inotropic support Decreasing pump ratio From 1:1 to 1:2 or 1:3 Decrease augmentation Monitor patient closely If patient becomes unstable, weaning should be immediately discontinued

46. IABP REMOVAL Discontinue heparin six hours prior Check platelets and coagulation factors Deflate the balloon Apply manual pressure above and below IABP insertion site Remove balloon while alternating pressure above and below insertion site to expel clots Apply constant pressure to the insertion site for a minimum of 30 minutes Check distal pulses frequently

47. KEY POINTS The primary goal of intra-aortic balloon pump (IABP) treatment is to increase myocardial oxygen supply and decrease myocardial oxygen demand. Decreased urine output after the insertion of IABP can occur because of juxta -renal balloon positioning. Haemolysis from mechanical damage to red blood cells can reduce the haematocrit by up to 5 %. Suboptimal timing of inflation and deflation of the balloon produces haemodynamic instability. An IABP is thrombogenic ; always anticoagulate the patient. Never switch the balloon off while  in situ .

48. ….THANK YOU….