Coronary artery grafting in high risk patients randomised to off pump or on pump surgery (CRISP)

Lead Research Organisation: University of Oxford
Department Name: Surgical Sciences


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Technical Summary

Conventional coronary artery bypass grafting (CABG) uses cardiopulmonary bypass (CPB) (?on-pump?) to support the circulation while the heart is temporarily stopped. CPB causes a systemic inflammatory response syndrome, which leads to multi-organ dysfunction, which although mild and reversible in the majority of patients can, contribute to overt morbidity and mortality, particularly in higher-risk patients. There is strong evidence from randomized trials, in low-risk populations, that OPCABG is at least as safe as ONCABG in terms of mortality and that OPCABG reduces several aspects of morbidity. There is less agreement on resource use consequences between on pump and off pump CABG. However, patients at high risk of operative mortality and morbidity have largely been excluded from these trials. The exclusion of high-risk patients from these trials is of key importance because there is consistent evidence from large prospective observational studies that OPCABG appears to reduce mortality and morbidity in such patients (although some studies have suggested a higher need for subsequent re-intervention with OPCABG). Although these observational studies have used propensity scoring and logistic regression analyses to minimize differences in baseline characteristics in the OPCABG and ONCABG groups they are nevertheless prone to all the potential limitations of non-randomized studies. CHOPS (CABG in High risk patients randomized to On Pump vs Off Pump Surgery) is proposed to test the hypothesis that OPCABG reduces mortality and morbidity in high-risk patients (without a higher risk of re-intervention) and to examine resource use .


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