Coronary
Haemodynamic Support Devices for Complex and High-risk Percutaneous Coronary Intervention
Kay Woon Ho and Vladimír Džavík Peter Munk Cardiac Centre, University Health Network, Toronto
Abstract
Patients at high risk, such as those with marked left ventricular dysfunction, acute coronary syndromes with unstable haemodynamics and arrhythmias, as well as single target vessels that supply a large area of myocardium, are undergoing percutaneous coronary intervention (PCI) with increasing frequency. Percutaneous haemodynamic support devices, including intra-aortic balloon counterpulsation pumps, percutaneous cardiopulmonary support and left ventricular assist devices, have been developed as adjunctive therapies during these complex procedures. Improvements in haemodynamic profiles with the use of these devices enhance procedural safety, allowing successful PCI to be performed in a more stable environment. Nevertheless, the use of these devices is associated with potentially serious complications and solid evidence for their routine use in high-risk PCI is lacking. Ongoing improvements in device designs and deployment techniques may eventually allow earlier, prophylactic use of support devices. Until then, the use of haemodynamic support devices should be individualised after careful consideration of the potential benefits and risks involved.
Keywords Percutaneous coronary intervention (PCI), percutaneous haemodynamic support, cardiogenic shock
Disclosure: Vladimír Džavík receives partial funding from the Brompton Funds Professorship in Interventional Cardiology and has received speaker’s honoraria from Abiomed Inc. Kay Woon Ho has no conflicts of interest to declare. Received: 7 December 2010 Accepted: 23 February 2011 Citation: Interventional Cardiology, 2011;6(1):17–24 Correspondence: Vladimír Džavík, Interventional Cardiology Program, Peter Munk Cardiac Centre, University Health Network, 6–246 EN Toronto General Hospital, 200 Elizabeth Street, Toronto, Ontario, Canada, M5G 2C4. E:
vlad.dzavik@
uhn.on.ca
Techniques and devices used in percutaneous coronary intervention (PCI) have evolved significantly since the inception of the procedure. Procedural and patient outcomes have improved, while more complex coronary lesions in high-risk patients are being attempted with increasing frequency. High-risk procedures are carried out in patients with marked left ventricular dysfunction, acute coronary syndromes – often with unstable haemodynamics and cardiac arrhythmias – as well as single target vessels that are survival- dependent or supply a large area of myocardium. Haemodynamic compensatory mechanisms are often extremely limited in such patients and transient ischaemia during PCI can rapidly lead to a downward spiral of haemodynamic collapse and death. Unsurprisingly, intervention in these high-risk situations often demands the prophylactic use of circulatory support devices. The use of intracoronary stents in the majority of PCI cases has dramatically reduced the incidence of abrupt closure and flow-limiting dissections. As a result, the focus of circulatory support during PCI has shifted from the maintenance of coronary perfusion, using techniques such as anterograde coronary perfusion or coronary sinus retroperfusion, to systemic haemodynamic stabilisation with mechanical support devices.1,2
Indications for haemodynamic support
devices have expanded from support during haemodynamic collapse to include prophylactic insertion for high-risk PCI. Percutaneous haemodynamic support devices can be classified into three major types, namely, the intra-aortic balloon counterpulsation pump (IABP), percutaneous cardiopulmonary support (CPS) and left ventricular
© TOUCH BRIEFINGS 2011
assist devices (VADs). The limitations and benefits of each device are summarised in Table 1. Evidence of their use in acute myocardial infarction (AMI)/emergent PCI and in elective high-risk PCI will be reviewed in detail.
Intra-aortic Balloon Counterpulsation The concept of using counterpulsation to support the failing heart was first described by Harken in 1958.3
In 1962, Moulopoulos
developed the counterpulsation principle and described the use of a single-chambered intra-aortic balloon positioned in the descending thoracic aorta.4
The balloon inflation begins with closure of the aortic valve until the onset of ventricular systole, when the balloon is rapidly deflated. Inflation of the balloon during diastole was postulated to augment coronary perfusion by displacing intra-aortic blood towards the coronary tree. Decreased pressure caused by deflation of the balloon results in reduced afterload and, consequently, less left ventricular work (see Figures 1 and 2). Six years later, Kantrowitz described the first clinical experience with IABP in patients in cardiogenic shock.5 Continued advancement in IABP technology over the years has led to expanded clinical applications and adoption of its use worldwide. A review of the IABP utility has revealed haemodynamic support during or after cardiac catheterisation as the most common clinical indication.6
Widespread availability in the modern cardiac catheterisation laboratory, familiarity with the device, its relatively low cost and ease of insertion are key advantages of the IABP. In addition to this, haemolysis is
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