Cobalt vs Platinum Chromium Stents: Trial Results

randomized-controlled-trial PMID: 23549491

Cobalt vs Platinum Chromium Stents: Trial Results

Quick Summary: This 2013 study compared two types of heart stents made with different chromium alloys—one using cobalt-chromium and the other platinum-chromium—in real-world patients needing artery-opening procedures. Researchers found no major differences in safety or effectiveness after 18 months, with both stents showing similar rates of survival without heart attacks, the need for repeat procedures, or blood clots. This means both options work about the same for everyday heart patients.

What The Research Found

Researchers tested two advanced heart stents designed to keep arteries open and prevent re-narrowing. These stents release a drug called everolimus to reduce scar tissue buildup. The key difference? Their metal bases: one is cobalt-chromium (CoCr-EES, like Xience Prime), and the other is platinum-chromium (PtCr-EES, like Promus Element).

In simple terms, the study showed both stents performed equally well. Here's what they measured:
- Survival without death or heart attack: 93.9% for cobalt-chromium vs. 91.3% for platinum-chromium (no big difference).
- Survival without needing another procedure: 95.2% vs. 94.5% (similar results).
- Overall success (no death, heart attack, or repeat procedure): 90.6% vs. 88% (again, no clear winner).
- Risk of blood clots in the stent: 1.3% vs. 0.66% (very low and comparable for both).
- No cases of stents getting squished out of shape during use.

These findings held up in a diverse group of patients, proving both stents are reliable in everyday medical practice. Note: "Chromium" here means the metal in the stent's structure, not the mineral you get from food like broccoli or supplements.

Study Details

Who was studied: 300 real-world heart patients getting artery procedures (called revascularization). Everyone qualified—no one was left out based on their health issues or artery problems. They were split evenly: half got the cobalt-chromium stent, half the platinum-chromium one. All could handle long-term blood-thinning meds.
How long: Patients were followed for 18 months to track long-term results.
What they took: No pills or supplements—the "treatment" was the stent itself, placed during a heart procedure (percutaneous coronary intervention, or PCI). Both stents slowly release everolimus, a drug that stops artery walls from overgrowing, but the metal alloy (with chromium) is what sets them apart.

What This Means For You

If you're facing a heart stent procedure, this study offers good news: Whether your doctor chooses a cobalt-chromium or platinum-chromium stent, both seem to give similar protection against heart attacks, the need for fixes, or clots over about a year and a half. It doesn't change the basics—stents help keep blood flowing to your heart—but it shows these modern versions (introduced around 2013) are on par, so your care team can pick based on your specific needs, like artery shape or size.

Talk to your doctor about your options; this isn't about dietary chromium (which supports blood sugar but isn't related here). Overall, it builds confidence in these life-saving devices for managing heart disease.

Study Limitations

Keep these in mind to understand the full picture—science isn't perfect:
- Small group size: Only 300 people, so it might miss tiny differences in rare problems like clots.
- Not long enough: 18 months is solid but doesn't show what happens years later.
- Varied patients: Including everyone made results more real-life, but mixed artery types could hide small stent differences.
- No deep checks: It focused on big health outcomes, not detailed artery scans or procedure ease.
- Possible bias: Doctors knew which stent they used, which might influence results slightly.

Larger studies since then back up that these stents are safe, but always ask your cardiologist for the latest on your case. Source: PubMed (2013).

Key Findings

This randomized controlled trial found no statistically significant differences in clinical outcomes between cobalt chromium everolimus-eluting stents (CoCr-EES) and platinum chromium EES (PtCr-EES) at 18 months. Survival free from death/infarction was 93.9% (CoCr) vs. 91.3% (PtCr) (P=0.3), survival without revascularization was 95.2% vs. 94.5% (P=0.6), and survival free from death, infarction, or revascularization was 90.6% vs. 88% (P=0.4). Thrombosis rates were 1.3% (CoCr) vs. 0.66% (PtCr) (P=0.9). No longitudinal stent compression occurred. The study concluded that both stents perform similarly in real-world scenarios but acknowledged insufficient power to detect minor differences.

Study Design

A randomized, all-comers trial conducted in 2013 with 300 patients undergoing revascularization. Participants were randomized 1:1 to receive CoCr-EES or PtCr-EES. No exclusion criteria were applied, allowing inclusion of diverse clinical presentations and lesion types. Follow-up occurred at 18 months.

Dosage & Administration

This study evaluated stent platforms, not nutritional chromium supplementation. The CoCr-EES (Xience Prime) and PtCr-EES (Promus Element) were administered via percutaneous coronary intervention (PCI). Everolimus, an antiproliferative drug, was eluted from both stents; the difference lay in the metal alloy (cobalt-chromium vs. platinum-chromium).

Results & Efficacy

Mortality/Infarction: 93.9% (CoCr) vs. 91.3% (PtCr) survival (P=0.3).
Revascularization: 95.2% (CoCr) vs. 94.5% (PtCr) survival (P=0.6).
Composite Endpoint: 90.6% (CoCr) vs. 88% (PtCr) survival (P=0.4).
Stent Thrombosis: 1.3% (CoCr) vs. 0.66% (PtCr) (P=0.9).
Longitudinal Compression: No cases observed in either group.
All outcomes showed nonsignificant differences (P > 0.05), but the study lacked power to detect small effect sizes.

Limitations

Sample Size: Only 300 patients, insufficient to identify minor differences in rare events (e.g., thrombosis).
Short Follow-Up: 18-month duration may not capture long-term stent performance.
All-Comers Design: While enhancing generalizability, heterogeneity in lesion complexity or clinical factors could obscure subtle differences.
Single-Endpoint Focus: Did not assess angiographic or procedural metrics (e.g., late lumen loss).
No Blinding: Device trials often lack blinding, introducing potential bias.

Clinical Relevance

For interventional cardiology, this study suggests CoCr-EES and PtCr-EES have comparable safety and efficacy in real-world populations. However, the small sample size limits definitive conclusions. Clinicians should consider these results alongside larger trials (e.g., SPIRIT IV) that demonstrated CoCr-EES superiority over older stents. Notably, this research does not address nutritional chromium supplementation; the term "chromium" here refers to alloy components in stent design, not dietary intake. Future studies with larger cohorts and extended follow-up are needed to validate these findings.

Source: PubMed (2013)