A subgroup of patients who experienced an out-of-hospital cardiac arrest (OHCA) that did not respond to standard advanced cardiac life support (ACLS), were immediately transported to a cardiac care center, and placed on a device similar to a heart-lung bypass machine were more likely to have survived with good brain function six months later than similar patients who received standard care at the site where the OHCA occurred. The study was presented at the American College of Cardiology's 70th Annual Scientific Session.
"This study--the largest randomized clinical trial that has been conducted to address this question--shows that a hyperinvasive approach is a feasible and effective treatment strategy for OHCA," said Jan Blohlávek, MD, PhD, professor of medicine at Charles University in Prague, Czech Republic, and lead author of the study.
Although the primary endpoint (six-month survival with good brain function as assessed by a validated scale for measuring cerebral performance after a cardiac arrest) was not met, the trial was stopped prematurely because the hyperinvasive approach showed efficacy in subgroups of patients.
Cardiac arrest occurs when a sudden malfunction of the heart's electrical system causes the heart to begin beating very erratically, which interrupts blood flow to the heart and brain. According to the Centers for Disease Control and Prevention, about 375,000 people have an OHCA every year in the U.S. The survival rate after an OHCA is about 12%. To survive, the patient must receive immediate cardiopulmonary resuscitation (CPR) to increase blood flow to the heart and brain and an electrical shock from a defibrillator to stop the abnormal heart rhythm.
The study involved 256 patients who experienced a witnessed OHCA. The patients' median age was 57 years and 92% were men. About 45% had high blood pressure and 20% had a history of coronary artery disease. They were randomly assigned to receive either standard advanced cardiac life support or hyperinvasive support.
Patients in the standard-care group (the S group) were treated at the site where the OHCA occurred with manual CPR, defibrillation, medications to reverse the cardiac arrest and other elements of usual care for a cardiac arrest. Patients in the hyperinvasive group (the H group) received mechanical CPR using a device that provided automatic chest compression and were transported immediately to a cardiac center where--if their heartbeat was not restarted en route--they were placed on an extracorporeal membrane oxygenation (ECMO) machine. This machine temporarily takes over the work of the heart and lungs by infusing fresh oxygen into the blood and pumping blood to the body's organs and tissues.
