DES Shows Slight Edge Over BMS in Patients with Kidney Disease

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More than 40% of older patients in need of percutaneous coronary intervention (PCI) have preexisting chronic kidney disease (CKD), according to a large registry study of Medicare patients published in the October 25, 2011, issue of the Journal of the American College of Cardiology. The study suggests that some of these patients may have better outcomes with drug-eluting stents (DES) vs. bare metal stents (BMS), especially in terms of death and myocardial infarction (MI).

Thomas T. Tsai, MD, MSc, of Denver VA Medical Center (Denver, CO), and colleagues examined outcomes data from the linked American College of Cardiology National Cardiovascular Data Registry (NCDR) and the Center for Medicare and Medicaid Services national claims databases to analyze 283,593 patients 65 years of age and older who underwent stent implantation with a DES (77.1%) or BMS (22.9%) between 2004 and 2007.

Patients were classified into 5 groups according to their estimated glomerular filtration rate (eGFR):

• Normal renal function (eGFR ≥ 60 ml/min/1.73 m²)
• Mild CKD (eGFR 45-59 ml/min/1.73 m²)
• Moderate CKD (eGFR 30-44 ml/min/1.73 m²)
• Severe CKD (eGFR < 30 ml/min/1.73 m²)
• Long-term dialysis

High CKD Prevalence

Overall, CKD was found in 42.8% of patients. The prevalence of mild, moderate, and severe CKD increased with age, whereas the prevalence of dialysis decreased. In addition, the proportion of patients with coexisting comorbidities increased with CKD severity.

Increasing severity of CKD was found to be associated with higher rates of mortality, MI, revascularization, and bleeding. In patients with severe CKD, the 30-month mortality rate was 32.7% (95% CI 31.2-34.1), while in patients on long-term dialysis, mortality escalated to 51.9% (95% CI 49.8-54.0). Dialysis patients had the highest adjusted rates of death (adjusted HR 3.55; 95% CI 3.36-3.74), MI (adjusted HR 2.11; 95% CI 1.91-2.31), and major bleeding (adjusted HR 2.27; 95% CI 1.97-2.60). This group also had significant increases in revascularization not seen in any other group.

Propensity-score matching showed an advantage with DES. Of 121,942 matched pairs, those who received a DES had lower 30-month death rates in most renal function categories compared with BMS (table 1).

Table 1. Death Rates at 30 Months by Stent Type and Renal Function Status

 
DES-treated patients also experienced overall lower rates of MI compared with BMS-treated patients (7.2% vs. 8.2%, P < 0.001). This was also seen in terms of lower adjusted 30-month MI rates in patients with normal renal function or mild, moderate, or severe CKD.

Overall revascularization rates at 30 months were slightly lower in the DES vs. BMS patients (18.1% vs. 18.4%, P < 0.001). Furthermore, there appeared to be a differential reduction in revascularization rates for DES vs. BMS (interaction P < 0.01) in patients with normal renal function only. Major bleeding rates at 30 months were slightly lower with DES compared with BMS (3.9% vs. 4.1%, P = 0.04). After adjustment, DES use in the severe CKD subgroup was associated with significant reductions in the incidence of 30-month hospitalizations for bleeding, whereas no differences were seen in the other groups.

Dr. Tsai and colleagues point out that no safety hazard was detected with the use of DES vs. BMS in this high-risk elderly population. They acknowledge that although a mortality benefit for DES has not been demonstrated in randomized, controlled trials, “this limitation could reflect limited follow-up, the enrollment of only low-risk patients with low event rates, or a relatively small number of patients.”

In the absence of a definitive randomized, controlled trial, they conclude, “this is the largest registry study to date that suggests that DES appear to be safe in older patients with varying levels of CKD undergoing PCIs.”

Differences Not That Great

But Morton J. Kern, MD, of the University of California, Irvine (Irvine, CA), told TCTMD in a telephone interview that while the researchers are to be congratulated on conducting such a large and involved study, the differences they found between DES and BMS are not great enough for him to recommend DES as the stent of choice in patients with CKD.

“There seems to be a little edge favoring DES but not in severe kidney disease,” he said. “At least it’s not worse, so that’s a good thing. It’s not surprising that the worse the kidney disease is, the worse people do, but honestly, there isn’t much here to overwhelmingly state that DES make a huge difference. If you want to prevent MI, then DES might be a better choice in patients with mild or moderate disease, but for long-term survival with GFR less than 30, nothing is going to help.”

Dr. Kern added that he would not expect to see a safety signal since nothing definitive has been suggested regarding greater risk of DES in patients with kidney disease.

Study Details 

BMS patients were significantly older with a higher prevalence of smoking and history of congestive heart failure, peripheral arterial disease, stroke, and chronic lung disease compared with patients treated with DES.

Patients receiving DES were more likely to have had a previous PCI and present for an elective PCI.

  

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Source:
Tsai TT, Messenger JC, Brennan JM, et al. Safety and efficacy of drug-eluting stents in older patients with chronic kidney disease: A report from the linked CathPCI registry-CMS claims database. J Am Coll Cardiol. 2011;58:1859-1869.

 

 

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