Coronary Revascularization in Diabetic Chronic Kidney Disease/End-Stage Renal Disease: A Nephrologist’s Perspective

ADAMTS13 Deficiency Shortens the Life Span of Mice With Experimental Diabetes

In patients with diabetes, impaired activity of ADAMTS13 (a disintegrin and metalloprotease with thrombospondin type 1 repeats, member 13), the plasma metalloprotease that cleaves highly thrombogenic von Willebrand factor multimers, is a major risk factor of cardiovascular events. Here, using Adamts13^-/- mice made diabetic by streptozotocin, we investigated the impact of the lack of ADAMTS13 on the development of diabetes-associated end-organ complications. Adamts13^-/- mice experienced a shorter life span than their diabetic wild-type littermates. It was surprising that animal death was not related to the occurrence of detectable thrombotic events. The lack of ADAMTS13 drastically increased the propensity for ventricular arrhythmias during dobutamine-induced stress in diabetic mice. Cardiomyocytes of diabetic Adamts13^-/- mice exhibited an aberrant distribution of the ventricular gap junction connexin 43 and increased phosphorylation of Ca²⁺/calmodulin-dependent kinase II (CaMKII), and with the consequent CaMKII-induced disturbance in Ca²⁺ handling, which underlie propensity for arrhythmia. In vitro, thrombospondin 1 (TSP1) promoted, in a paracrine manner, CaMKII phosphorylation in murine HL-1 cardiomyocytes, and ADAMTS13 acted to inhibit TSP1-induced CaMKII activation. In conclusion, the deficiency of ADAMTS13 may underlie the onset of lethal arrhythmias in diabetes through increased CaMKII phosphorylation in cardiomyocytes. Our findings disclose a novel function for ADAMTS13 beyond its antithrombotic activity.

Effect of revascularization strategy in patients with acute myocardial infarction and renal insufficiency with multivessel disease

BACKGROUND/AIMS

The aim of this study was to compare the risk of complications and outcome between infarct-related artery (IRA)-only revascularization and multivessel (MV) revascularization in patients with acute myocardial infarction (MI) with renal insufficiency and MV disease.

METHODS

A total of 1,031 acute MI patients with renal insufficiency and MV disease who were registered in the Korea Working Group on Myocardial Infarction were enrolled. They were divided into two groups (IRA-only revascularization group, n = 404; MV revascularization group, n = 627), and investigated the cumulative incidence of major adverse cardiac events (MACE) and the incidence of complications after percutaneous coronary intervention (PCI).

RESULTS

Complications after PCI occurred in 19.9% of all patients (206/1,031). Complications after PCI occurred more frequently in the MV revascularization group compared with the IRA-only revascularization group (20.1% [126/627] vs. 15.3% [62/404], respectively; p = 0.029]. The overall in-hospital mortality rate was 6.3%, and there was no significant difference between the groups (5.2% in the IRA-only revascularization group vs. 7.0% in the MV revascularization group; p = 0.241). The total incidence of MACE was 11.1%, and there was no significant difference between the groups (11.6% in the IRA-only revascularization group vs. 10.7% in the MV revascularization group; p = 0.636).

CONCLUSIONS

The incidence of complications after PCI was significantly lower in the IRA-only revascularization group compared with the MV revascularization group. However, there were no significant difference in the 12-month outcomes between groups in patients with acute MI and renal insufficiency with MV disease.

Cardiac risk assessment by gated single-photon emission computed tomography in asymptomatic end-stage renal disease patients at the start of dialysis

OBJECTIVES

This study assessed the impact of cardiac risk assessment using gated single-photon emission computed tomography (SPECT) on cardiac events in end-stage renal disease (ESRD) patients.

METHODS

We evaluated 215 asymptomatic patients who began dialysis between January 2005 and April 2009. Baseline electrocardiography and echocardiography were performed in all the patients. The subjects were stratified into low- and high-risk groups according to the baseline cardiac status, and gated SPECT was additionally recommended for the high-risk patients.

RESULTS

The study population consisted of 50 low- and 165 high-risk patients undergoing SPECT. Among the high-risk patients, 75 (45.5%) showed perfusion defects on SPECT and their overall cardiac-event rate per person-year of follow-up was 15.0%, significantly higher than 4.5% in high-risk group without perfusion defect and 1.2% in low-risk group. The presence of perfusion defect was a significant independent predictor of adverse cardiac events [hazard ratio (HR) 2.11; 95% confidence interval (CI) 1.05-4.24; P = .035]. When gated SPECT was added to the clinical and the echocardiographic variables, the prognostic stratification significantly improved (P < .001). However, coronary revascularization was not associated with improved cardiac event-free survival (HR 0.62; 95% CI 0.26-1.52; P = .296).

CONCLUSIONS

Gated SPECT may provide additional prognostic information for cardiac risk stratification, particularly among high-risk patients starting dialysis.

A renal transplant patient with abdominal discomfort, vomiting and diarrhoea for 1 week

The patient is a 61-year-old diabetic male with history of renal transplant who presented to the emergency department with complaints of intermittent abdominal discomfort accompanied by multiple episodes of vomiting and diarrhoea. He had delayed seeking medical attention until his friends insisted that he come to the emergency department, since the abdominal discomfort was worsening. The patient's ECG revealed an ST-segment elevation myocardial infarction.

Use of drug-eluting stents in patients with coronary artery disease and renal insufficiency

Renal insufficiency (RI) has been shown to be associated with increased major adverse cardiovascular events after percutaneous coronary intervention. We reviewed the impact of RI on the pathogenesis of coronary artery disease and outcomes after percutaneous coronary intervention in the form of drug-eluting stent (DES) implantation in these high-risk patients. We searched the English-language literature indexed in MEDLINE, Scopus, and EBSCO Host research databases from 1990 through January 2009, using as search terms coronary revascularization, drug-eluting stent, and renal insufficiency. Studies that assessed DES implantation in patients with various degrees of RI were selected for review. Most of the available data were extracted from observational studies, and data from randomized trials formed the basis of a post hoc analysis. The outcomes after coronary revascularization were less favorable in patients with RI than in those with normal renal function. In patients with RI, DES implantation yielded better outcomes than did use of bare-metal stents. Randomized trials are needed to define optimal treatment of these high-risk patients with coronary artery disease.

Diabetic kidney disease in the older adult: an update

The kidneys are among the most prominent body organs affected by the process of aging, as both kidney morphology and function are known to change with age. However, special challenges emerge when the elderly patient also has diabetes complicated by kidney disease. Cases frequently progress from the early stages of diabetic nephropathy to advanced kidney impairment and end-stage renal disease, and the majority of patients suffer cardiovascular complications. However, many elderly patients with diabetes will lack the classic clinical features of diabetic kidney disease. Neither the efficacy nor safety of general treatment goals such as glycemic control, hypertension management and renin–angiotensin blockade have been adequately addressed in the aging diabetic kidney patient. These basic treatments for diabetic kidney disease are extrapolated from studies of mostly middle-aged individuals. Diabetic kidney guidelines do not adequately distinguish between age groups. Aggressive management must be measured against life expectancy in the elderly. The physician should be aware of these risks. Unfortunately, many elderly diabetic chronic kidney disease/end-stage renal disease patients are not prescribed the treatments that are available. Over a third of new end-stage renal disease cases among the elderly are due to diabetic kidney disease. Prognosis is poor, even for those who receive a kidney transplant.

Percutaneous coronary intervention versus coronary artery bypass grafting in patients with coronary artery disease and diabetic nephropathy: a single center experience

BACKGROUND

Patients with diabetic nephropathy (DN) and coronary artery disease (CAD) represent a subset of patients with high cardiovascular morbidity and mortality. The optimal revascularization strategy using either percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) remains controversial. The purpose of this study was to compare the clinical outcomes of PCI to CABG in DN patients with CAD.

METHODS

The clinical and angiographic records of DN patients with CAD who underwent either CABG (n=52) or PCI (n=48) were retrospectively analyzed.

RESULTS

The baseline characteristics were similar in the two groups except for the severity of the CAD. At 30 days, the death rate (PCI: 2.1% vs. CABG: 9.6%, p=0.21) and major adverse cardiac events (MACE) rate (PCI: 2.1% vs. CABG: 9.6%, p=0.21) were similar in comparisons between the PCI and CABG groups. At three years, the death rate (PCI: 18.8% vs. CABG: 19.2%, p=0.94) was similar between the PCI and CABG groups but the MACE rate (PCI: 47.9% vs. CABG: 21.2%, p=0.006) was higher in the PCI group compared to the CABG group. In addition, the repeat revascularization rate was higher in the PCI group compared to the CABG group (PCI: 12.5% vs. CABG: 1.9%, p=0.046).

CONCLUSIONS

The CABG procedure was associated with a lower incidence of MACE and repeat revascularization for up to three years of follow-up in DN patients with CAD. However, the overall survival rate was similar in the CABG and PCI groups. Therefore, CABG may be superior to PCI with regard to MACE and repeat revascularization.