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Limitations to the value of the Sapphire trial
1University of Leicester, University Hospitals of Leicester NHS Trust.
Insights
The Sapphire trial compared carotid endarterectomy (CEA) and stenting (CAS) in high-risk patients. Despite findings of similar stroke and death rates, the trial
Area of Science:
- Vascular Surgery
- Interventional Cardiology
- Clinical Trial Methodology
Background:
- Carotid endarterectomy (CEA) and carotid angioplasty with stenting (CAS) are procedures to prevent stroke.
- The Sapphire trial aimed to compare CEA and CAS in high-risk patients.
Purpose of the Study:
- To critically evaluate the methodology and conclusions of the Sapphire trial.
- To assess the scientific validity of the trial's findings regarding CEA versus CAS in high-risk patients.
Main Methods:
- Review of the Sapphire trial's design, funding, and patient selection.
- Analysis of reported endpoints, surgeon experience, and patient characteristics.
- Identification of potential biases and limitations within the trial.
Main Results:
- The Sapphire trial concluded CEA and CAS had similar stroke/death rates, but CAS had fewer complications.
- Significant methodological flaws were identified, including commercial funding, lack of investigator equipoise, biased endpoints, and surgeon inexperience.
- High patient exclusion rates and heterogeneous patient populations (including asymptomatic individuals) raise concerns about generalizability.
Conclusions:
- The Sapphire trial's conclusions regarding the equivalence of CAS and CEA in high-risk patients are not scientifically justified due to identified flaws.
- Methodological weaknesses undermine the reliability of the trial's findings.
- Further rigorous trials are needed to definitively compare CEA and CAS in specific patient populations.
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.
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