Author + information
- Ranjit Shah, MBBS,
- Jonathan M. Gleadle, BM, BCh, DPhil and
- Joseph B. Selvanayagam, MBBS, DPhil∗ ()
- ↵∗Flinders University, College of Medicine and Public Health, Sturt Road, Bedford Park, South Australia 5042, Australia
We read with interest the recent study by Winther et al. (1) that addressed the best noninvasive or invasive test for predicting cardiac prognosis in asymptomatic chronic kidney disease (CKD) patients. In this study, 154 patients referred for kidney transplantation assessment underwent coronary artery calcium score, coronary computed tomography angiography, single-photon emission computed tomography, and invasive coronary angiography and were followed up for a mean of 3.7 years. The primary endpoint was major adverse cardiac events (MACE) defined as 1 of the following events: cardiac death, cardiac arrest with successful resuscitation, ST-segment elevation myocardial infarction, non–ST-segment elevation myocardial infarction, or coronary revascularization. The secondary endpoint was all-cause mortality. Coronary artery calcium and abnormal coronary computed tomography angiography and invasive coronary angiography findings were predictive of MACE even after adjustment for renal transplantation and presence of more than 3 risk factors during follow-up.
This study is important, as patients with advanced renal failure have a high cardiovascular risk and cardiovascular mortality accounts for one-half of all deaths in patients with end-stage renal disease receiving dialysis (2,3). Furthermore, although renal transplantation significantly improves survival, cardiovascular disease is still one of the most frequent causes of death accounting for 35% to 50% of all-cause mortality (4). All current screening options have some limitations and there is no consensus about the optimal mode of screening.
The study raises some important questions that require clarification. First, it appears that the treating clinicians were not blinded to the results of the study investigations. Hence, patients who had revascularization procedures in relation to the baseline cardiac evaluation do not appear to have been excluded from follow-up, and these patients (5%) are counted as part of MACE outcome. This is inappropriate and artificially increases the number of MACE events. Second, we are not informed if medical therapy was altered as a result of the study investigations. Third, the units for the laboratory findings are not given, and we are surprised by the very low levels of mean hemoglobin in their population (7.3 g/dl).
Finally, we would like to mention other noninvasive methods of evaluation for coronary artery disease that are being currently studied in the renal failure population. Blood oxygen level–dependent (BOLD) cardiac magnetic resonance (CMR) uses the paramagnetic properties of deoxygenated hemoglobin as an intrinsic contrast and can thus directly indicate the oxygenation status of the myocardium. The BOLD CMR technique can be particularly useful in CKD participants, as it has a high sensitivity to detect myocardial ischemia, and does not involve exposure to radiation or extrinsic contrast agents. In a recent study, BOLD CMR demonstrated significant blunted myocardial oxygenation response to stress in asymptomatic CKD patients (5), and may have prognostic value.
Please note: The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- 2018 American College of Cardiology Foundation
- Winther S.,
- Svensson M.,
- Jorgensen H.S.,
- et al.
- Parnham S.F.,
- Gleadle J.M.,
- De Pasquale C.G.,
- Selvanayagam J.B.
- Dimeny E.M.
- Parnham S.,
- Gleadle J.M.,
- Bangalore S.,
- et al.