IABP support is often initiated in the cardiac catheterization laboratory and continued through the perioperative period. Weaning from cardiopulmonary bypass may be difficult in cases where aortic cross-clamping is prolonged, revascularization is only partially achieved, or pre-existing myocardial dysfunction is present.
Separation from cardiopulmonary bypass may be marked by hypotension and a low cardiac index despite the administration of inotropic drugs. It is contraindicated in patients with aortic regurgitation because it worsens the magnitude of regurgitation. IABP insertion should not be attempted in case of suspected or known aortic dissection because inadvertent balloon placement in the false lumen may result in extension of the dissection or even aortic rupture. Similarly, aortic rupture can occur if IABP is inserted in patients with sizable abdominal aortic aneurysms.
Patients with end-stage cardiac disease should not be considered for IABP unless as a bridge to ventricular assist device or cardiac transplantation. IABP device placement should be avoided in patients with severe peripheral vascular disease. Percutaneous femoral IABP device insertion is contraindicated in the presence of bilateral femoral—popliteal bypass grafts. Uncontrolled sepsis and bleeding diathesis are relative contraindications to the placement of IABP device.
The IABP device has two major components: i a double-lumen 8. The balloon is made of polyethylene and is inflated with gas driven by the pump. Helium is often used because its low density facilitates rapid transfer of gas from console to the balloon.
It is also easily absorbed into the blood stream in case of rupture of the balloon. Smaller balloons are available for paediatric use. The IABP catheter is inserted percutaneously into the femoral artery through an introducer sheath using the modified Seldinger technique.
Alternative routes of access include subclavian, axillary, brachial, or iliac arteries. The catheter can also be inserted surgically using a transthoracic or translumbar approach, but this is associated with an increased periprocedural mortality.
Intraoperatively, balloon placement can be ascertained using transoesophageal echocardiography. The outer lumen of the catheter is used for delivery of gas to the balloon and the inner lumen can be used for monitoring systemic arterial pressure. The console is programmed to identify a trigger for balloon inflation and deflation. The most commonly used triggers are the ECG waveform and the systemic arterial pressure waveform.
The balloon inflates with the onset of diastole, which corresponds with the middle of the T-wave. The balloon deflates at the onset of LV systole and this corresponds to the peak of the R-wave.
Poor ECG quality, electrical interference, and cardiac arrhythmias can result in erratic balloon inflation. The balloon is set to inflate after the aortic valve closure which corresponds to the dicrotic notch on the arterial waveform and deflate immediately before the opening of the aortic valve which corresponds to the point just before the upstroke on the arterial pressure waveform. The cardiac cycle is monitored by continuous display of the arterial pressure waveform. Balloon inflation causes augmentation of diastolic pressure and a second peak is observed.
This peak is referred to as diastolic augmentation. However, the device should never be left unused in situ to prevent thrombosis. One complete cardiac cycle and the corresponding waveform of the IABP during inflation and deflation. Cheers Chris. Leave a Reply Cancel reply. We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. In case of sale of your personal information, you may opt out by using the link Do not sell my personal information.
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These cookies will be stored in your browser only with your consent. You also have the option to opt-out of these cookies. But opting out of some of these cookies may have an effect on your browsing experience. Krakauer et al. They stated that counterpulsation could beneficially affect hemodynamic measurements. Ventricular end-diastolic pressure can be decreased, thereby reducing myocardial tension with a proportionate decrease in myocardial oxygen consumption. The coronary arterial perfusion pressure is increased and this together with reduced myocardial tension and decreased systolic ejection time permits enhancement of coronary blood flow.
They concluded that the group of patients treated with balloon support early following the onset of the shock had a significant better prognosis. In Bregman and coworkers [ 14 ] developed a dual chamber balloon consisting of a large proximal and a small distal balloon which inflated first; the idea was to block distal blood flow and augment flow proximally to the brain and coronary arteries.
The development of catheters and balloons of polyurethane material enable prolonged periods of counterpulsation. In two different groups [ 15 , 16 ] reported the successful utilization of IABP in patients who were unable to be weaned from cardiopulmonary bypass. Therefore, IABP support opened a new era in the perioperative management of patients with ventricular dysfunction during cardiac surgery. Continuous evolution brought a method of insertion of the balloon catheter percutaneously without the need for surgical cut down [ 17 , 18 ].
Invasive Cardiologists then adopted this method; that transformed the entire field of IABP due to the aggressive expansion of indications for use of this device to different subsets of patients with advanced coronary artery disease unresponsive to medical management.
During the past decade major mechanical and engineering developments have allowed optimal timing of counterpulsation and on-line monitoring of blood pressure and cardiac output. The IABP console delivers a specific volume of gas through a pneumatic system into a balloon during a predetermined time interval followed by retrieval of the gas, Fig. The console contains:. Description of the circuit between the patient and the intraaortic balloon pump IABP.
The IABP console includes the following: 1 A gas cylinder usually helium, which has a theoretical advantage according to Hendrickx et al [ 14 ]; 2 a gas supply unit; 3 a monitoring system for recording the ECG and blood pressure; 4 a control unit that processes the ECG and generates a triggering signal. The latter unit is used for the timing of inflation and deflation of the balloon via activation of the valve unit, either opening the valve to supply gas or closing it to interrupt the gas flow.
Control unit which processes the electrocardiogram and develops a trigger signal; this is used for timing of balloon inflation and deflation by activating the valve unit and allowing either opening of the valve in order to deliver the gas, or closure of the valve unit in order to stop the gas flow.
Both Helium and Carbon dioxide have been used as driving gases, however the use of helium has theoretical advantages according to Hendrickx et al.
The latter statement confirmed by Kantrowitz and colleaques who stated that the balloon is limited by the volume of blood contained within the aorta just prior to inflation ie. The aortic volume doubles between a shock mean of 30 to 40 mm of Hg and a normal mean pressure of 80 to 90 mm of Hg. Further increases in pumping volume result only in distention of the aorta due to aortic elasticity and not in the effective pumping of the balloon.
While in many clinical situations volume of 40 cc are appropriate, it should be said that too large IAB increases vascular morbidity whereas too small IAB reduces the cardiac benefit. Diastolic augmentation is maximized when stroke volume is equal to balloon volume. If stroke volume is very low ie 25—30 ml or very high 95— ml augmentation will be decreased. The closer the balloon is to the aortic valve, the greater the diastolic pressure elevation.
It is obvious that local anatomical factors limit the position of the balloon within the aortic arch therefore the optimal balloon position will be that where the tip is situated distal to the left Subclavian artery take off.
The proximal balloon end should be lying above the renal vessels. Incorrect balloon position results in reduced diastolic augmentation or vascular morbidity due to direct intimal injury or plaque distortion and embolization or finally direct occlusion of the arterial lumen. Following the principle of counterpulsation, the IAB is deflated during systole which coincides with QRS —T interval R wave always triggers balloon deflation. In this manner balloon inflation during cardiac systole is prevented.
Haemodynamic function of the balloon. Cardiovascular consequences are mainly due to the effect on preload and afterload [ 20 ].
Intraaortic balloon counterpulsation is instituted by insertion of a catheter mounted with a distensible polyurethane balloon in the patients descending aorta.
Helium gas is shuttled from the balloon pump console. Inflation occurs immediately upon onset of diastole. Deflation occurs during isometric contraction. In a mechanical sense balloon inflation causes volume displacement. Total or regional blood flow is potentially improved with counterpulsation. Coronary circulation and perfusion to the aortic arch trifurcated vessels is potentially increased. Balloon inflation augments the intrinsic Windkessel effect, which augments peripheral perfusion [ 23 ].
At the time of deflation intraaortic blood volume is decreased with concomitant lowering of pressure. This process occurs at the end of diastole just as isovolumetric contraction is commencing and reduces the impedance against which the left ventricle must eject. Therefore decreasing afterload [ 24 ]. A decrease in aortic systolic pressure in the course of balloon pumping indicates proper systolic unloading and afterload reduction. According to Norman et al.
The Aortic valve during balloon pumping opens early therefore the isometric phase of LV contraction is decreased. This time interval is proportionally related to myocardial oxygen consumption [ 28 ]. Likewise there is an increase in Cardiac Output between 0. There is a shift of the curve to the left showing improvement of the left ventricular function.
This has been used as a prognostic indicator: by enlarged survivors show a sustained effect while non survivors show a shift to the right indicating ventricular deterioration. The relation between left ventricular diastolic pressure change and left ventricular diastolic volume change LV stiffness exhibits a trend towards reduced values [ 34 ], a fact that translates into an improvement in left ventricular compliance. DPTI reflects diastolic and subendocardial blood flow and depends on aortic diastolic pressure, left ventricular end diastolic pressure and diastolic duration.
The area under the left ventricular systolic pressure curve, which reflects myocardial oxygen demand, is termed tension time index TTI. TTI decreases with balloon deflation due to a decrease in systolic blood pressure. A value of 1.
An EVR of less than 0. Phillips et al. Bolooki et al. It has to be clarified that TTI as an index of oxygen demand only accounts for pressure; on the other hand myocardial oxygen consumption is a function of force that is proportional to both pressure and volume, therefore although EVR will only reflect the decrease in pressure IABC produces a decrease in volume as well as pressure.
As a consequence the decrease in myocardial oxygen consumption will be underestimated. Balloon inflation displaces blood proximally increasing coronary perfusion by also increasing diastolic pressure and the diastolic perfusion gradient [ 37 , 38 ]. There are various animal studies that assessed the contribution of the intra aortic balloon on myocardial perfusion.
Results were variable. Kern et al. In ischaemic animal models with low systemic arterial pressure myocardial oxygen consumption became dependent on coronary flow. IABP had little effect on perfusion to myocardial regions supplied by occluded coronary vessels.
Gewirtz et al. McDonald et al. However Folland and associates [ 42 ] contradicted this report. They observed relieved anginal symptoms in a population with coronary artery disease and concomitant severe aortic disease.
They concluded that improvement in coronary flow must occur with pumping. Freedman and associates [ 43 ] called myoconservation technique the initiation of IABC. He stated that the balloon action stimulated collateral circulation in the area surrounding the core of myocardial damage.
Fuchs et al. Kern and associates [ 45 ] assessed intracoronary flow velocity during catheterization in 12 patients treated with IABC.
They concluded that IABC augments proximal coronary blood flow velocity by doubling the coronary flow velocity integral. During counterpulsation aortic end diastolic pressure is lowered.
Applying Laplaces low, lowering of aortic end diastolic pressure during static work refers to development and maintenance of ventricular pressure before opening of the aortic valve will decrease the amount of tension generated at the time the aortic valve opens. Therefore reducing myocardial oxygen consumption.
Akyurekli et al. This was carried out by counterpulsating dogs while their coronary arteries were perfused from an extracorporeal source. The perfusion pressure was lowered to produce acute cardiac failure. During hypotension, aortic compliance increases which causes the aortic wall to expand with inflation of the balloon, therefore blood volume displacement does not occur.
Moreover at the time of deflation, aortic pressure will not be lowered. Static work and myocardial oxygen consumption will therefore not be lowered. Peripheral blood flow is determined by pressure, resistance, length and viscosity.
Balloon inflation during diastole increases the arterial pressure, which increases the arterial-venous gradient and thus improves flow. In addition balloon inflation in diastole displaces stroke volume and thus activation of the aortic baroreceptors inhibits the medullary vasoconstrictor reflex. Peripheral resistance decreases, which, as demonstrated by Poiseuilles low improves blood flow.
The impact of IABC on splachnic blood flow has also been studied. Landreneau et al. The IABP group was found to have a return to preshock splachnic visceral perfusion without the hyperemic reperfusion phenomenon seen in control animals.
They concluded that IABPC during hemorrhagic shock appears to improve vasomotor control of splachnic blood flow by eliminating the hyperemic reperfusion phenomenon resulting in less reperfusion injury. Swartz et al. This paper is worth mentioned because it outlines the variables that influence diastolic pressure augmentation during balloon inflation [ 50 ].
The variables are:. Balloon Volume: When the balloon volume is equal to the stroke volume the diastolic augmentation is maximized. Balloon diameter and occlusivity: The greatest augmentation occurs with complete aortic occlusion. Stroke volume: If stroke volume is less than 25 ml little diastolic augmentation can be expected.
Arterial pressure: The significance of aortic elasticity is illustrated by the fact that aortic volume doubles between a mean arterial pressure of 30 mmHg and a normal mean pressure of 90 mmHg. Our group [ 51 ] calculated an algorithm for optimal balloon sizing in order to improve diastolic augmentation and minimise patient-balloon mismatching. This of course is dependent on the case mix and stratifying patients according to the Euroscore, one would obviously suggest that IABP usage correlates with ascending scoring.
The unique physiological balance of benefits of IABP, include support of the coronary circulation [ 52 , 53 ], as well as reduction in left ventricular stress and reduction in cardiac work-load [ 54 ]. Temporary support of the left ventricular function due to cardiac failure, due to myocardial infarction or due to intraoperative injury. However the efficacy of IABP is dependent upon the phase of myocardial ischaemia or the time elapsed from initiation of myocardial infarction as well as the stage of left ventricular function.
The value of the balloon pump as a circulatory assist device in the treatment of cardiogenic shock is well established [ 55 — 57 ]. Singh et al. Triple Vessel disease with moderately preserved left ventricular function and good distal targets. Significant mechanical lesions such as mitral insufficiency or ischaemic ventricular septal defect. Various clinicians must agree that during ischaemic episodes there is a potential window of opportunity were adequate hemodynamic support would ensure that adequate myocardium would remain viable to allow resumption of function, following coronary artery bypass grafting [ 59 , 60 ].
This is the concept of myoconservation and where the intraaortic balloon pump exerts major impact. Gold and associates [ 61 ] showed that the usage of IABP abolishes the pain, ameliorates ST segment elevation and prevents left ventricular tachyarrhytmia.
The same group showed that [ 62 ] if the balloon treatment was followed with a CABG then outcome was statistically better than if the balloon treatment had not been instituted. In unstable patients especially in the presence of left ventricular dysfunction, the use of IABP allows safe performance of diagnostic studies followed by surgical intervention. Zhang et al. Langou and associates [ 64 ] report in 75 patients following the same regimen they had a 5.
Furthermore a study of 55 patients with a similar presentation who were operated on without IABP, Although the majority are not controlled non-matched series, they however still indicate that patients who are refractory to maximal medical therapy can be operated on with IABP stabilization with a low operative mortality and a low peri-operative infarction rate [ 65 , 66 ].
Incremental risk factors for death include the subgroup of patients with poor left ventricular function, left main stem disease, left ventricular hypertrophy, unfavourable coronary anatomy, diabetic obese females and concomitant end-stage aortic valve disease.
In Theory, IABP could be used during acute myocardial infarction in order to decrease the size of the infarct, to support the cardiac function, to prevent infarct extension and to reduce complications associated with the event. Miller and associates [ 67 ] published their clinical experience at St. O Rourke et al. In cardiogenic shock, the pump is having a hard time pumping — so stroke work is something you want to try to reduce — which is exactly what balloon deflation does.
Rapid deflation of the balloon creates an area of lowered pressure in the aorta just ahead of the emptying left ventricle. Sort of like suction. The suction helps empty the ventricle with each beat, and takes some of the workload off of the cardiogenic heart.
Almost everyone with cardiogenic shock died before the invention of the IABP because there was no way to assist the failing LV — now the survival numbers are pretty good. The two big bad timing errors are early inflation and late deflation. Early inflation is just that — the inflation knob is turned too far to the left, and the inflation wave actually comes before the dicrotic notch. To the left of it. This means that the balloon is inflating before the aortic valve closes, pumping backwards into the LV, which is already having a hard time emptying itself….
Late deflation is when the balloon remains inflated too long — the heart is trying now to pump against an inflated balloon. The deflation knob has been turned too far to the right — move it back towards the center. In the current Datascope cs- this rate can be adjusted down to a rate of 50 BPM? It depends on why the balloon went in. Remember that there are two main reasons for an IABP — to help keep tight lesions open in the coronary arteries inflation , or to help a failing LV in cardiogenic shock deflation.
In that situation, anticoagulation is really of critical importance — do you want to be the one that let the patient clot off her brand new stents? The second situation is more difficult, but hopefully somewhat predictable. What is there to recover? The goal of ballooning this patient is to get them through that period of time, with the balloon functioning as an LVAD — a left-ventricular assist-device. Catch the latest Perfusion news or peruse our article archive.
February 8, Frank What is an intra-aortic balloon pump? How much volume do es the balloon hold? The balloon itself can hold different volumes, 34cc, 40cc, and 50cc.
Why do they use helium? What are tight lesions? What is stable angina? Unstable angina? How do I know if the balloon is working? What are V-waves? Why do they come and go? What is cardiogenic shock? How can I tell if the balloon is working?
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