Limitations to the Value of the Sapphire Trial

Abstract

The Sapphire trial was organised as a randomised trial to compare carotid endarterectomy (CEA) with carotid angioplasty and stenting (CAS) using a protection device in so called high risk patients. The trial concluded that CEA and CAS were similar as far as stroke and death are concerned but CAS was superior when other complications were taken into account. The trial was flawed for several reasons. It was commercially funded and the inventor of the protection device was one of the investigators and therefore not in equipoise. The end points of the trial favoured CAS by making a biochemical myocardial event an end point. The surgeons doing CEA in the trial did relatively few CEA’S per year and had a high stroke and death rate. These surgeons also excluded over 400 patients from the trial because they were said to be too difficult or risky to operate on. The precise reasons for this exclusion have never been made clear except that the surgeons were probably inexperienced. Finally the patients were heterogeneous, more than 70% being asymptomatic or suffering from recurrent stenosis. For all of these reasons the Sapphire trial’s conclusions that CAS is equivalent to CEA in high risk patients cannot be scientifically justified.