Myocardial microvascular disease and major adverse cardiovascular events in patients with end-stage renal disease: rationale and design of the MICROCARD study.

Background: Myocardial ischaemia, a consequence of coronary artery disease, is a major cause of death in patients with end-stage renal disease (ESRD). The pathophysiology and clinical presentation of coronary artery disease in ESRD patients seem to differ from non-ESRD patients with higher implication of myocardial microvascular disease (MMD), higher mortality, fewer myocardial infarctions, less significant coronary stenosis and low efficacy of well-established drugs such as statin and angiotensin-converting enzyme inhibitors. No study has investigated the presence of MMD and its clinical impact in ESRD patients.

Methods: We designed an observational prospective cohort study to investigate the prevalence of MMD and its association with major adverse cardiovascular events (MACE) in ESRD patients with a positive non-invasive test for myocardial ischaemia. Patients eligible for inclusion are those>18 years old receiving dialysis and/or undergoing investigation for kidney transplantation, who are referred to our renal clinic and meet all the inclusion criteria but none of the exclusion criteria. Patients with a positive test for myocardial ischaemia will be enrolled in the 'invasive group'. They will be further examined to detect simultaneously epicardial coronary stenosis by coronary angiography and MMD using pressure wire measurement of fractional flow reserve and coronary flow reserve followed by calculation of the index of microcirculatory resistance. Patients with a negative test for myocardial ischaemia will be enrolled in a 'control group' designed to verify whether the invasive group is indeed at high risk for MACE. Both groups will be followed up for 2 years to compare the incidence of MACE.

Conclusion: The MICROCARD study will phenotype MMD and will investigate its relation with the incidence of MACE in ESRD patients with myocardial ischaemia. Clinicaltrial.gov NCT01291771.