|Year : 2008 | Volume
| Issue : 4 | Page : 387
Intra Aortic Balloon Pump (IABP): Past, Present and Future
Jatin D Dedhia1, Kotemane R Naren Chakravarthy2, Aamer B Ahmed3
1 SpR in Anaesthetics, Leicester Royal Infirmary, Leicester, LE5 1WW, United Kingdom
2 SpR in Anaesthetics, Leicester General Hospital, Leicester, LE5 4PW, United Kingdom
3 Consultant Cardiothoracic Anaesthetist, Glenfield General Hospital, Leicester, LE3 1WW, United Kingdom
|Date of Acceptance||22-May-2008|
|Date of Web Publication||19-Mar-2010|
Aamer B Ahmed
Consultant Cardiothoracic Anaesthetist, Glenfield General Hospital, Leicester, LE3 1WW
Source of Support: None, Conflict of Interest: None
Intra Aortic Balloon Pump (IABP) is the most commonly used mechanical circulatory assist device in cardiac patients. IABP can improve ventricular function by decreasing the preload and increasing systolic output with significant improvement in myocardial oxygen supply/demand ratio. Pre-operative IABP therapy in 'high-risk' coronary patients has been shown to reduce hospital mortality and shorten ICU stay significantly, compared with controls. The introduction of sheathless insertion kits has reduced the incidence of vascular complication rates. Pro-Active Counter Pulsation is a new IABP system which automatically detects the irregular pattern and result is an improvement in the haemodynamic effect of IABP during periods of arrhythmia. Today, continued improvements in IABP technology permit safer use and earlier intervention to provide haemodynamic support. These developments have made the IABP a mainstay in the management of ischemic and dysfunctional myocardium. This review article aims to provide basic concept of IABP to hospital doctors especially anaesthetists, intensivists cardiologists and cardiac surgeons. It discusses the common indications, contraindications, the physiologic aspects of IABP, the equipment needed to facilitate IABP, the use of the IABP in special situations and complications of its use.
Keywords: Intra Aortic Balloon Pump, Coronary blood flow, Oxygen supply/demand, ProActive Counter Pulsation, Console.
|How to cite this article:|
Dedhia JD, Naren Chakravarthy KR, Ahmed AB. Intra Aortic Balloon Pump (IABP): Past, Present and Future. Indian J Anaesth 2008;52:387
|How to cite this URL:|
Dedhia JD, Naren Chakravarthy KR, Ahmed AB. Intra Aortic Balloon Pump (IABP): Past, Present and Future. Indian J Anaesth [serial online] 2008 [cited 2020 Feb 22];52:387. Available from: http://www.ijaweb.org/text.asp?2008/52/4/387/60652
| Introduction|| |
IABP is the most common mechanical circulatory assistance device used in clinical practice since the last 35 years.
Initially mechanical support was developed in 1951 and was used for open intra-cardiac operations (heart-lung machine). This device could perform the entire functions of the cardio-pulmonary system. Later, to help the patients with acute left ventricular systolic dysfunction in association with excessive preload, assist pumps were devised, which work by temporary diversion of excess preload from the heart and its return to the patient. This helps the failing heart to recover.
In 1960s, the concept of counter-pulsation was introduced. The fundamental basis of this concept was dependence of coronary blood flow on diastolic blood pressure. This was achieved by rapid withdrawal of arterial blood from the femoral artery during systole and by its re-infusion during diastole. Thus, systolic unloading and diastolic augmentation were accomplished. This concept led to the development of the intra-aortic balloon pump (IABP) by Moulopoulosetal. ,
More recently, sophisticated and innovative devices have been developed which are capable of delivering a greater degree of assistance to the failing left ventricle (LV) for a longer period (circulatory assist with an auxiliary pump). These devices have a variety of booster pumps that remove blood from the left heart or from the ascending aorta during systole and return it to the aorta during diastole, thereby augmenting the diastolic blood pressure. An abdominal left ventricular assist device (LVAD) is capable of assisting the left ventricle three to five times as much as an IABP.
Despite the increasing popularity of using circulatory assist devices with an auxiliary pump, these were associated with few drawbacks - like lack of control over the after load and the neurohormonal component, which occurs due to changes in stroke volume, association with trauma to blood elements and haemolysis. But IABP offers a simple method of circulatory assist that can achieve ventricular improvement (decrease in preload) and increase in systolic output with significant improvement in myocardial oxygen supply/demand ratio. Today, continued improvements in IABP technology permit safer use and earlier intervention to provide haemodynamic support. Preoperative IABP-therapy in 'high-risk' coronary patients have been shown to reduce hospital mortality and shorten ICU stay significantly, compared with controls.  These developments have made the IABP a mainstay in the management of ischemic and dysfunctional myocardium.
This review article discusses the common indications and contraindications [Table 1], the physiologic aspects of IABP, the equipment needed to facilitate IABP, the use of the IABP in special situations and complications of its use.
Establishing intra-aortic balloon counterpulsation requires the insertion of the catheter and connecting it to the console.
| Balloon Pump Console|| |
The drive console consists of a pressurized gas reservoir, a monitor for ECG and pressure wave recording, adjustments for inflation/deflation timing and triggering selection switches. It is portable, light weight and has the option of mains and battery operation. There are two types of consoles, Stationary and Portable. Stationary consoles are used at the bedside and for short distance transport. Portable consoles are used for long distance transfer. The gases used for inflation are either helium or carbon dioxide. Helium has low density and rapid diffusion coefficient. However carbon dioxide has an increased solubility in blood, which reduces the potential consequences of gas embolization following a balloon rupture. A standard console comprises the following features:
- Rear panel which consists of DC input, IAB fill and drain port, helium supply, and patient connections
- Monitor which displays alarms, ECG , IAB status, pressure source, operation mode, battery and helium indicators,
- Key pad controls
- Recorder to record ECG, pressure and balloon pressure waveform
- System battery which displays charge status and portable operation
- Doppler storage facility
Balloon catheters are presented in a sterile insertion kit and are disposable and single use only. Balloon catheters are made of polyurethane and are manufactured in sizes varying from 8.5F to 10.5F. For children sizes are available between 4.5F to 7F. The adult catheters have a standard length of 32.5 inches. The volume of the balloon is 30-40 ml in adults and 2.5-25 ml in children.
The balloon catheter is placed via the femoral artery using a modified Seldinger technique. The patient is heparinised prior to insertion of catheter providing there are no contra-indications such as recent surgery. After cardiac surgery patient should be given low-molecular weight dextran at 20ml.hr -1 instead of heparin. The balloon is fully collapsed applying 30ml vacuum with 60ml syringe. The femoral artery is punctured and a J-shaped guide wire is inserted to the level of the aortic arch and then the needle is removed. An 8Fr to 10.5Fr dilator/sheath combination is used to enlarge the arterial puncture side. The balloon is threaded over the guide wire into the descending aorta just below the left subclavian artery [Figure 2]. The sheath is pulled back to connect with the cuff on the balloon hub. The correct placement of the IAB is in the descending aorta with its tip at the distal aortic arch (below the origin of the left subclavian artery).
Doppler ankle pressures should be monitored and compared with the pre-insertion value. Vascular complication rates are lower after IABP insertion using smaller sized catheter and a sheathless technique. The sheathless method of insertion should be preferred in patients with diabetes mellitus and peripheral vascular disease , .
Physiology of coronary circulation
Myocardial blood supply is from the right and left coronary arteries. The dependence of coronary blood flow on diastolic pressure is due to the mechanical compression of coronary blood vessels within the myocardium during systole. Left heart pressures are much higher than the right side. As a result the right side of the heart is better perfused during systole compared to the left side. The coronary vascular bed is auto regulated balancing myocardial oxygen supply and demand [Table 2]. Coronary vascular resistance is influenced by neural, metabolic and haemodynamic factors. The coronary arteries are innervated by the sympathetic and parasympathetic nervous systems. Alpha receptor stimulation causes vasoconstriction while stimulation of the beta-2 receptor and the vagus nerve causes vasodilatation. Regional perfusion is regulated by metabolic factors. Several mediators such as carbon dioxide, adenosine, hydrogen ions, phosphate, prostaglandins and potassium cause vasodilatation. When coronary perfusion pressure falls to below 60 mmHg, auto regulation is lost, the coronary vessels become maximally dilated and blood flow depends only on perfusion pressure. Haemodynamic factors that affect coronary perfusion include arterial pressure (diastolic pressure), diastolic time and the intra-ventricular pressure.
Physiologic effects of IABP therapy:
After confirming the correct placement, the balloon is connected to a drive console. The IABP is a volume displacement device designed to provide partial assistance to the left ventricle by inflation and deflation of IAB catheter synchronized to the patient's cardiac cycle [Figure 3].
By deflating the balloon just prior to the ventricular systole, inertial resistance to blood flow is reduced and left ventricular afterload falls. This results in increased stroke volume and cardiac output (10-40%), decrease in heart rate and pulmonary artery wedge pressures.
Inflation of the balloon at the commencement of the diastole results in increased aortic diastolic pressure (up to 70%). Since diastolic blood flow is responsible for 70% of cardiac perfusion, coronary and cardiac flow should theoretically increase. There is a fall in peak systolic arterial pressure of 5%-15%, with no change in mean arterial pressures.
The ultimate aim is to increase myocardial oxygen supply and decrease myocardial oxygen demand.
Inflation and deflation need to be correctly timed to the patient's cardiac cycle. There are seven triggering modes on the Arrow International IABP console.
- ECG PATTERN: The height, width and slope of a positively or negatively deflected QRS complex are analysed by the IABP machine. This is the preset (default) trigger mode.
- ECG PEAK: The height and slope of a positively or negatively deflected QRS complex are analysed by the IABP machine. This is the trigger mode of choice in wide complex rhythms.
- A-FIB: The QRS complex is analysed in the same manner as in the peak mode. This is the trigger mode of choice in varying R-R intervals as in atrial fibrillation.
- V PACE: Ventricular signal is used as the trigger signal. This is the trigger mode of choice in 100% ventricular or AV paced rhythms.
- A PACE: Atrial spike is used as the trigger signal. This is the trigger mode of choice in 100% atrial paced rhythms.
- ARTERIAL PRESSURE: Systolic upstroke of the arterial pressure waveform as the trigger signal. This is the trigger mode of choice where ECG signals are distorted or unavailable.
- INTERNAL: The balloon inflates and deflates at a preset rate regardless of the patient's cardiac activity. This mode is used in situations where there is no cardiac output or ECG is unavailable.
Timing and weaning
Inflation of the IAB should occur at the beginning of diastole, coinciding with the dicrotic notch on the arterial waveform. Deflation of the balloon should occur immediately prior to the arterial upstroke. Balloon synchronization starts usually at a beat ratio of 1:2. Weaning from the IABP may begin by gradually decreasing the balloon augmentation ratio. It must be ensured that the patient has a sufficiently high platelet count (>100 000/mm 3 ) prior to removal. Direct pressure to the arterial puncture site should be applied for duration of 30 minutes after removal.
| ProActive Counter Pulsation:|| |
ProActive Counter Pulsation is a new IABP system which incorporates two new and unique technologies, the WAVE timing algorithm and the ability to monitor the Arterial Pressure (AP) signal from a Fibre Optic Source (FOS) using the Fiber Optix™ IAB catheter. WAVE is an acronym for the Windkessel Aortic Valve Equation, which automatically sets inflation timing to occur precisely at the time of the Aortic Valve Closure (AVC).
The WAVE algorithm converts the arterial pressure (AP) waveform to understand the patient's aortic flow in the cardiac cycle [Figure 4]. Aortic valve closure occurs at the lowest point in the flow wave, after peak flow occurs. Timing is set within each beat (intra-beat) for that specific beat, as it occurs. This results in highly accurate inflation timing, which is specific to that beat, for that patient at that moment in time.
For setting deflation timing, during an arrhythmia the IABP system automatically detects the irregular pattern and sets a conservative deflation to occur while assessing the balloon's performance in relation to the patient's cardiac cycle. The combination of the WAVE inflation timing with automatic 'R'-Wave deflation timing results in real-time, beat to beat timing, which corresponds to the changes in the patient's cardiac cycle. The result is an improvement in the haemodynamic effect of IABP during periods of arrhythmia.
The Fiber Optix™ IAB catheter [Figure 5] incorporates fibre optic sensor technology into the tip of the IAB catheter. Once zeroed prior to insertion, it does not require any further maintenance, such as re-zeroing or flush systems. It is immune to electrical interference, patient movement or activities that interfere with the quality of the arterial pressure signal, such as transport.
- Selects ECG and AP signal sources upon connection
- Changes ECG and AP sources as required to maintain triggering
- Selects trigger mode based on patient conditions such as heart rate and rhythm
- Selects timing method based on available signals
- Sets and adjusts timing in response to patient's needs.
Use of low molecular weight dextran and prophylactic heparin will reduce the incidence of IABP related vascular complications, the majority of which are thromboembolic in nature. Other complications are listed in [Table 3].
Vascular complication rates vary from 6%-24%. Patients with longer balloon duration have increased risk of a major complication.  Limb ischemia leads to fasciotomy or amputation. Aortic dissection is managed by balloon removal. Thromboembolic complication can be reduced by proper evaluation of peripheral circulation by palpating pedal pulses and documenting ankle pressures on hourly basis.  Absent pulses after IAB removal may need thrombectomy. In the event of visceral arterial occlusion therapy is dictated by specific end organ dysfunction. False aneurysm which are generally associated with previous wound infection, require operative repair.
Balloon rupture is attributed to rough handling and is recognised by failure to achieve diastolic augmentation and by appearance of blood in balloon shaft. Prompt recognition of cerebral air embolism secondary to IABP rupture requires a high level of suspicion and is confirmed by CT scan of Head.  Treatment consists of immediate discontinuation of counter pulsation, the application of suction to the balloon, placing the patient in Trendelenburg's position, and IAB replacement. IAB entrapment is unusual sequela of balloon membrane rupture and needs open removal.  Excessive advancement of balloon causes intermittent obstruction of arch vessels. When the caudal end of the IAB is located within the abdominal aorta, renal and mesenteric obstruction can occur. The use of fluoroscopy during balloon placement and chest roentgenogram should eliminate this problem.
Septic complications include fever, bacteremia, superficial and deep wound infection. Positive blood cultures will guide to appropriate antibiotic therapy. Wound infections may need surgical intervention.
Haemorrhagic complications results from bleeding from insertion site or systemic anticoagulation therapy. Groin wound hemorrhage can often be controlled with compressive dressing. Complication due to systemic anticoagulation therapy consists of correcting the coagulopathy and removing IAB. Balloon-dependent patients can be adequately protected with low molecular weight dextran.
Haemodynamic monitoring plays an important role in the management of patients with heart failure. The variables which help in assessment include heart rate, central venous pressure, arterial blood pressure, pulmonary artery pressure, pulmonary capillary wedge pressure and cardiac output.
Heart rate reflects cardiac performance, bearing in mind it may also be affected by other factors. Central arterial blood pressure such as that from the femoral artery is more accurate in the presence of peripheral vasoconstriction. Central venous pressure (CVP) is usually reliable in the absence of heart failure. Pulmonary artery pressure (PAP) and pulmonary capillary wedge pressure (PCWP) are very useful in the presence of heart failure. They are measured using a Swan-Ganz pulmonary artery flotation catheter. The device helps to measure left and right sided filling pressures and diagnose rare complications. Variations in central venous oximetry reflect changes in cardiac output in a linear fashion in the presence of stable oxygen consumption. Cardiac output measurements are undertaken by the thermo-dilution technique and are taken at 6 to 8 hour intervals and at any time when the plan of therapy or the patient condition is changed.
| Data Acquisition|| |
Data acquisitionincludescalculationofclinicallyuseful data. They are cardiac index, left to right shunt, stroke volume, stroke index, stroke work, left ventricular stroke work index and systemic vascular resistance. These parameters can be calculated using appropriate formulas. 
1) Cardiac index = CI (l/min/m2) = cardiac out put /body surface area
2) Stroke volume = SV (ml) = cardiac output / heart rate
3) Stroke work = SW (g.m) = MAP - PCWP/HR
4) Left ventricular stroke work index = LVSWI
(g.m/m 2 ) = SW/BSA
5) Systemic vascular resistance = SVR (dyne/sec/cm -5 ) = (MAP - CVP) 80/CO
(MAP - mean arterial blood pressure, PCWP - pulmonary capillary wedge pressure, CO - cardiac output, HR - heart rate, BSA - body surface area, CVP - central venous pressure)
It may be best to position the patients horizontally to gain the full benefits of balloon counterpulsation to the coronary circulation.  The efficacy of diastolic augmentation can be assessed by clinical improvement in patient's condition and haemodynamic parameters. Clinically, an awake comfortable patient with reduced frequency and severity of angina is a good sign. Other signs include a change in skin temperature, reduction in sweating, a decrease in heart rate and episodes of arrhythmia, an improvement in urine output and the appearance of peripheral pulses. Haemodynamic parameters include a reduction in PCWP, an increase in arterial blood pressure, cardiac output and stroke work index.
Systemic management of patients on IABP
Other systems need careful attention and management in patients on IABP. These include renal, respiratory, haematological, nutritional and neuropsychiatric management. A decrease in cardiac output and blood pressure due to cardiac failure results in decrease in renal plasma flow and renal impairment. In high-risk patients undergoing OPCAB (off pump coronary artery bypass), routine preoperative insertion of IABP electively reduces the incidence of acute renal failure.  . Haemodialysis may be required in patients with high potassium, uraemia, fluid overload and severe acidosis. Patients admitted with acute myocardial infarction frequently have pulmonary congestion. Mechanical ventilation is required for patients with respiratory failure secondary to cardiac failure, after general anaesthesia and cardiac or respiratory arrest.
The presence of central lines and invasive catheters need antibiotic prophylaxis.  Hyperthermia increases myocardial oxygen consumption and should be treated aggressively. Anticoagulant therapy should be instituted in patients on IABP. Neuro-psychiatric problems can be challenging to deal with and are usually due to prolonged cardiopulmonary bypass. In ITU, haloperidol is used successfully in the treatment of these problems. In patients receiving IABP therapy for more than 2 days nutritional support should be instituted as soon as possible.  Ambulation of patients should be instituted as soon as the IABP catheter is removed.
IABP in special circumstances
Patients with impaired cardiac function are at highrisk of developing complications when undergoing general anaesthesia and surgery. Use of IABP support preoperatively for non-cardiac surgery in high-risk patients may be useful in providing haemodynamic stability. , IABP increases coronary blood flow and improves tissue perfusion in patients with septic shock.  The use of IABP has been recommended for patients with blunt cardiac injury and overdose of certain drugs, who fail to respond to conventional treatment. , IABP in conjunction with cardiopulmonary resuscitation has been shown to improve coronary perfusion pressure. 
IABP therapy has been used in children with cardiac anomalies and heart failure. IABP therapy can serve as an alternative to ECMO- membrane oxygenators. 
Trouble shooting when using IABP
Problems may arise while using the equipment for counterpulsation. A knowledge of the basic problem encountered will increase efficiency in management [Table 4].
Recent advances and conclusion
IABP therapy for patients with cardiovascular and systemic conditions is currently well established. Preoperative intra aortic balloon pump therapy in high risk patients has been significantly cost-beneficial.  In the modern-day practice of IABP therapy, complication rates are generally low.  Advances in technology have permitted patients to be treated with greater safety and effectiveness. Recently IABP balloon catheter which can be used in patients irrespective of their physical size has been developed. A long soft tip is used, which is designed to avoid damage to blood vessels and the catheter can be used as a multifunctional balloon catheter, that allows simultaneous percutaneous coronary intervention (PCI). The safety of this catheter has been proven in scientific studies.  Reports show that specially trained critical care paramedics can safely transfer IABP dependant patients to definitive cardiac surgical care without additional medical escorts.  IABP therapy will continue to have a lead role in providing temporary mechanical cardiovascular support in near future.
| References|| |
|1.||Moulopoulos SD, Stephen R, Topaz S et al. Extracorporeal assistance to the circulation and intra-aortic balloon pumping. Trans Am Soc Artif Int Org 1962;7:85-89. |
|2.||Moulopoulos SD, Topaz S, Kolff WJ. Diastolic balloon pumping (with carbon dioxide) in the aorta - A mechanical assistance to the failing circulation. Am Heart J 1962;63:669-75. |
|3.||Christenson JT, Simonet F, Schmuziger M. The intraaortic balloon pump as preoperative therapy in highrisk coronary patients. Journal of Congestive Heart Failure& Circulatory Support 2000;1:127-131. |
|4.||Anwar A, Mooney MR, Stertzer SH, et al. Intra-aortic balloon counter-pulsation support for elective coronary angioplasty in the setting of poor left ventricular function: A two centre experience. J Invasive Cardio 1990;2:175-80. |
|5.||Kreidieh I, Davies DW, Lim R, Nathan AW, Dymond DS, Banim SO. High-risk coronary angioplasty with elective Intra-Aortic balloon pump support. Int J Cardiol 1992;35:147-52. |
|6.||Erdogan, Hasan Basri, et al. In which patients should sheathless iabp be used? An analysis of vascular complications in 1211 cases. Journal of Cardiac Surgery 2006; 21:342-346. |
|7.||Menon P, Totaro P, Youhana A, Argano V. Reduced vascular complication after IABP insertion using smaller sized catheter and sheathless technique. Eur J Cardiothorac Surg 2002;22:491-492. |
|8.||Shin H, Yozu R, Sumida T, Kawada S. Acute ischemic hepatic failure resulting from Intra-Aortic balloon pump malposition. Eur J Cardiothorac 2000;17:492-494. |
|9.||Cook L, Pillar B, McCord G, Josephson R. Intra-aortic balloon pump complications: A five-year retrospective study of 283 patients, Heart Lung 1999;28:195-202. |
|10.||Meharwal ZS, Trehan N. Vascular complications of intra-aortic balloon insertion in patients undergoing coronary reavscularization: analysis of 911 cases. Eur J Cardiothorac Surg 2002;21:741-747. |
|11.||Cruz-Flores S, Diamond AL, Leira EC. Cerebral air embolism secondary to intra-aortic balloon pump rupture. Neurocritical Care 2005;2:49-50. |
|12.||Richenbacher WE, William S. Pierce. Management of complications of intraaortic ballon counterpulsation. In: John A. Waldhausen, Mark B. Orringer. Complication in Cardiothoracic Surgery. Mosby Year Book Inc;1991:97-102. |
|13.||Hooshang Bolooki. Haemodynamic monitoring, data acquisition and assessment of efficacy of diastolic augmentation. In:Clinical application of the Intra-Aortic Balloon Pump, 3rd edition, Blackwell Publishing 1984;13:261-262. |
|14.||Khir, Ashraf W et al. Intra-aortic balloon pumping: Does posture matter? Artificial Organs 2005;29:36-40. |
|15.||Vohra, Hunaid A, Dimitri, Wadih R. Elective intraaortic balloon counter-pulsation in high-risk off-pump coronary artery bypass grafting. Journal of Cardiac Surgery 2006;21:1-5. |
|16.||Arnold M, Reed WA. Surgery in the chest. In: Kaplan BM(ed): Antimicrobial therapy. Philadelphia: WB Saunders Co,1974:312. |
|17.||Paccagnella A, Calo M, Cipolotti G, et al. Total Parenteral nutrition in patients with intra aortic balloon counterpulsation. Scandinavian J Thorac Cardiovasc Surg 1993; 27: 35-40. |
|18.||Grotz R L,Yeston N S. Intra-aortic balloon counterpulsation in high-risk cardiac patients undergoing non-cardiac surgery. Surgery 1989;1:106. |
|19.||Masaki E, Takinami M, Kurata Y, et al. Anesthetic management of high-risk cardiac patients undergoing noncardiac surgery under the support of intra-aortic balloon pump. J Clin Anesth 1999;11:342-347. |
|20.||Mercer D, Doris P, Salerno TA. Intra-aortic balloon pump counterpulsation in septic shock. Can J Surg 1981;24:643-45. |
|21.||David J S, Gueugniaud P Y, Hepp A, et al. Severe heart failure secondary to 5-fluorouracil and low doses of folinic acid: Usefulness of an intra-aortic balloon pump. Crit Care Med 2000;28:3558-60. |
|22.||Demas C, Flancbaum L, Scott G. The intra-aortic balloon pump as an adjunctive therapy for severe myocardial contusion. Am.J.Emerg.Med 1987;5:499-502. |
|23.||Emmerman C L, Pinchak A C, Hagen J F, Hancock D. Haemodynamic effects of the intra-aortic balloon pump during experimental cardiac arrest. Am J Emerg Med 1989;7:378-83. |
|24.||Pinkney K A, Minich L L,Tani L Y et al. Current results with intra-aortic balloon pumping in infants and children. Ann Thorac Surg 2002;73:887-91. |
|25.||Christenson JT, Simonet F, Schmuziger M. Economic impact of preoperative intra-aortic balloon pump therapy in high-risk coronary patients. Ann Thorac Surg 2000;70:510-515. |
|26.||James J. Ferguson, Marc Cohen, Freedman RJ, et al. The current practice of intra-aortic balloon counterpulsation: results from the Benchmark Registry. Journal of the American College of Cardiology 2001;38:1456-1462. |
|27.||Tsutsui, Nobumasa et al. Optimization and safety of the intra-aortic balloon pumping balloon catheter. Journal of Artificial Organs 2007;10:143-148. |
|28.||MacDonald, Russell1; Farquhar, Steve. Transfer of intra-aortic balloon pump-dependent patients by paramedics. Prehospital Emergency Care 2005;9:449-453. |
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
[Table 1], [Table 2], [Table 3], [Table 4]