Interventionalists Get Pumped Up About Mechanical Chest Compression

	(A) Stent placement in patient during LUCAS chest compression. (B) TIMI 3 flow in left anterior descending artery after the procedure. Source: Kristoff Cornelis, MD, Antwerp Cardiovascular Institute Middelheim, Belgium

If Europe is any indication of where mechanical cardiopulmonary resuscitation (CPR) is heading, interventional cardiologists in the U.S. should get ready to welcome the devices into their cath labs. European researchers have begun to validate the technique in arrested patients undergoing PCI.

There is a general reluctance to take arrested patients to the cath lab, even though the majority of arrests are cardiac in origin. Two factors emerge as important reasons for this reluctance: unknown brain perfusion, which could lead to a poor outcome or cath lab death, and the challenges to perform CPR during a catheterization procedure, such as radiation exposure to hands or the need to stop frequently.

These data are borne from results of a survey of 75 interventional cardiologists conducted at the 2008 American College of Cardiology (ACC) meeting by HRA Associates at the behest of ZOLL Medical, makers of the AutoPulse cardiac support pump. Survey results showed that most cardiologists would consider intervention if adequate blood pressure was attained during resuscitation (65 percent); if they were confident that cerebral perfusion was maintained (85 percent); and if there were a device that could provide near normal perfusion, allow good visualization and perform chest compressions without human intervention (71 percent). However, only 5 percent of respondents had ever used such a device, and only 11 percent had seen one being used. 

Validation of devices

Preclinical studies have demonstrated improved hemodynamics when using an automated resuscitation device versus conventional CPR. Clinical studies also have shown the value of such devices with out-of-hospital and in-hospital cardiac arrest patients. Researchers have more recently begun to look at whether arrest patients treated out-of-hospital with mechanical CPR have an improved survival following PCI and whether mechanical CPR during PCI is feasible.

Kristoff Cornelis, MD, and colleagues from Antwerp Cardiovascular Institute Middelheim and AZ Maria Middelares in Belgium successfully applied CPR with the LUCAS chest compression device (Physio-Control) to five patients undergoing PCI. The two stable patients completely recovered, while the three unstable patients died, despite successful intervention and application of mechanical CPR. The study was presented at the 2008 European Resuscitation Council Congress. (See images at left)

The Belgian researchers reported that the LUCAS device was introduced into their emergency department more than a year ago and has been used in the cath lab during procedures complicated by cardiac arrest and cardiogenic shock or during procedures performed in patients already under mechanical CPR, started out-of-hospital or in the emergency department.

Larsen et al from Stavanger University Hospital, Norway, reported that the LUCAS device is suitable during cardiac cath and ensures an adequate systemic blood pressure. In their study, 13 patients within 13 months were treated with PCI while undergoing mechanical CPR (Resuscitation 2007 Dec;75[3]:454-9). The mean systolic and diastolic blood pressure obtained was 81 and 34 mmHg, respectively. Angiography and PCI were possible in all cases during ongoing automatic chest compression and there were no excessive intra-thoracic or intra-abdominal injuries. Three patients survived the procedure, but no patients were discharged alive.

Safety, ease of use

Several studies have validated the safety of these devices in terms of chest injuries. In one study, Sergio Timerman, MD, and colleagues from Sao Paulo University School of Medicine, Brazil, and Johns Hopkins University in Baltimore used the AutoPulse to measure the peak force generated with compression and the pressure generated by the compression (Resuscitation 2004;[61]:273-280).

Researchers found that the device generated a greater peak force (mean 125 kg) than manual CPR (51 kg). The mechanical device, however, distributed its force across the chest more uniformly, thereby, reducing the risk of injury. The mean force measured at the sternum for AutoPulse was 203 mmHg, while for manual CPR it was 1381 mmHg.

Bela Merkely, MD, director of the Cardiovascular Center at Semmelweis University in Budapest, Hungary, and colleagues perform about 2,500 PCIs a year, with approximately 1,500 of them being acute. Among the high-risk patients, many have cardiogenic shock and many are operated on after successful resuscitation. Within the last year and a half, interventional cardiologists have used the AutoPulse in nearly 100 cases.

Some of the benefits of using the device are that the design allows effective compression on a cath lab table; it safeguards the staff from x-ray exposure; it maintains the integrity of the sterile working area; and there are no compromises between PCI and other actions, according to Merkely.

As Grogaard et al put it, “Mechanical chest compression devices have shown encouraging results…. An early revascularization strategy would, therefore, seem reasonable, if ischemia is suspected, in a cardiac arrested patient with prolonged unsuccessful [advance cardiac life support].” (J Am Coll Cardiol 2007;50(11):1093-4)