Safety and effectiveness of drug-eluting stents versus bare-metal stents in elderly patients with small coronary vessel disease

Drug-coated balloon for the treatment of small vessel disease: 9 months of angiographic results and 12 months of clinical outcomes of the PEPCAD China SVD study

BACKGROUND

Whether the drug-coated balloons (DCBs)-alone strategy was superior to plain old balloon angioplasty (POBA) in treating SVD remains unknown.

AIMS

We aimed to evaluate the efficacy and safety of DCBs for the treatment of coronary de novo small vessel disease (SVD) and provide further evidence for extending the clinical indications of DCBs. (ChiCTR1800014966).

METHODS

Eligible patients were randomized at a 2:1 ratio to receive DCB treatment or POBA in this prospective, multicenter clinical trial. The reference vessel diameter of lesions was visually assessed to be 2.0 to 2.75 mm. The primary endpoint of the study was angiographic in-segment late luminal loss (LLL) at the 9-month follow-up to demonstrate the superiority of DCB treatment to POBA in SVD. The composite clinical endpoints included clinically driven target lesion revascularization (CD-TLR), target lesion failure (TLF), major adverse cardiac events (MACEs), and thrombosis at the 12-month follow-up.

RESULTS

A total of 270 patients were enrolled (181 for DCB, 89 for POBA) at 18 centers in China. The primary endpoint of 9-month in-segment LLL in the intention-to-treat population was 0.10 ± 0.33 mm with DCB and 0.25 ± 0.38 mm with POBA (p = 0.0027). This difference indicated significant superiority of DCB treatment (95% CI: -0.22, -0.04, p_superiority  = 0.0068). The rates of the clinical endpoints-CD-TLR, TLF, and MACEs-were comparable between groups. No thrombosis events were reported.

CONCLUSIONS

DCB treatment of de novo SVD was superior to POBA with lower 9-month in-segment LLL. The rates of clinical events were comparable between the two devices.

Use of drug-eluting stents in elderly patients with acute myocardial infarction: An analysis of the Hungarian Myocardial Infarction Registry

BACKGROUND

Bare-metal stents (BMS) are frequently implanted in elderly patients instead of drug-eluting stents (DES). We aimed to compare the prognosis of patients treated for myocardial infarction with the two types of stents over the age of 75.

METHODS

Data of patients registered in the Hungarian Myocardial Infarction Registry, a mandatory nationwide programme for hospitals treating patients with myocardial infarction were processed. From patients included between January 2014 and December 2017 we created two groups according to DES and BMS implantation. The outcome measures included all-cause mortality, the composite of cardiac events (MACE), repeated revascularisation and transfusion. Propensity score matching was used to balance the groups and Cox proportional hazards' models to estimate the risk during the 1st year after the index event.

RESULTS

From 7383 patients (age: 81.08 ± 4.38 years) 3266 (44.2%) patients received DES. The PS-matched cohort included 5780 cases with balanced characteristics. In the DES group, the mortality (HR 0.66 [0.60-0.72]), MACE (HR 0.66 [0.60-0.72]) and the rate of transfusion (HR 0.84 [0.73-0.97]) were significantly lower. The PS-matched cohort showed a similar trend but with a lower rate of benefits with a 21% reduction of mortality and 23% of MACE. Difference in transfusion did not reach the level of significance. In multivariate models, stent type prevailed as an independent predictor of mortality and but not of transfusion.

CONCLUSIONS

Based on our analysis of a real-life, high-risk population, implantation of DES seems to be an advantageous strategy for elderly patients.

Approaches to treatment effect heterogeneity in the presence of confounding

The literature on causal effect estimation tends to focus on the population mean estimand, which is less informative as medical treatments are becoming more personalized and there is increasing awareness that subpopulations of individuals may experience a group-specific effect that differs from the population average. In fact, it is possible that there is underlying systematic effect heterogeneity that is obscured by focusing on the population mean estimand. In this context, understanding which covariates contribute to this treatment effect heterogeneity (TEH) and how these covariates determine the differential treatment effect (TE) is an important consideration. Towards such an understanding, this paper briefly reviews three approaches used in making causal inferences and conducts a simulation study to compare these approaches according to their performance in an exploratory evaluation of TEH when the heterogeneous subgroups are not known a priori. Performance metrics include the detection of any heterogeneity, the identification and characterization of heterogeneous subgroups, and unconfounded estimation of the TE within subgroups. The methods are then deployed in a comparative effectiveness evaluation of drug-eluting versus bare-metal stents among 54 099 Medicare beneficiaries in the continental United States admitted to a hospital with acute myocardial infarction in 2008.

Initial and late efficacy of everolimus-eluting stents for small and non-small coronary lesions from evaluating delayed late loss study

The aim of the present study was to evaluate the long-term outcomes at 2 years in patients in whom everolimus-eluting stents (EESs) were implanted in small and non-small vessels. A small vessel is an important risk factor for restenosis with BMSs, even in the first generation DESs. The 690 patients with 690 lesions implanted with an EES were enrolled and divided into two groups by vessel reference diameter (RD): >2.5 mm for non-small vessels (Non-S-group) and ≤2.5 mm for small vessels (S-group). Two years later, the 365 patients with no restenosis at 8 months who underwent angiography were enrolled into the late catch-up study. At the initial 8-month follow-up, the rates of restenosis and target lesion revascularization (TLR) of both groups were not significantly different (restenosis 3.9 vs 6.5%, p = 0.17; TLR 3.9 vs 6.5%, p = 0.17). At the late 2-year follow-up, there were no significant differences in the late loss (0.36 ± 0.66 vs 0.34 ± 0.50 mm, p = 0.14), net gain (1.50 ± 0.75 vs 1.26 ± 0.60 mm, p = 0.39), late catch-up restenosis rate (5.1 vs 3.4%, p = 0.38), TLR (4.9 vs 2.7%, p = 0.40), and delayed late loss (0.14 ± 0.58 vs 0.15 ± 0.49 mm, p = 0.10) between both groups. There is no correlation between delayed late loss and RD in all patients(r = -0.009) and in AMI patients (r = -0.004). These results demonstrate that the initial and late catch-up restenosis rates of small coronary vessels with EES placement were excellent, the same as for non-small coronary vessels. We suggest that involvement of small coronary arteries may not be a risk factor for restenosis and results of stenting for small coronary arteries with EES placement were excellent.

Improved outcomes of elderly patients treated with drug-eluting versus bare metal stents in large coronary arteries: results from the BAsel Stent Kosten-Effektivitäts Trial PROspective Validation Examination randomized trial

BACKGROUND

Drug-eluting stents (DES) improve outcomes in elderly patients with small coronary artery disease compared with bare-metal stents (BMS), but randomized data in elderly patients in need of large coronary stents are not available.

METHODS

Planned secondary analysis of patients ≥75 years recruited to the "BASKET-PROVE" trial, in which 2,314 patients undergoing percutaneous coronary intervention for large (≥3.0 mm) native vessel disease were randomized 2:1 to DES (everolimus- vs sirolimus-eluting stents 1:1) versus BMS. All patients received 12 months of dual antiplatelet therapy. The primary end point was a composite of cardiac death or nonfatal myocardial infarction at 2 years.

RESULTS

Comparison of DES versus BMS among 405 patients ≥75 years showed significantly lower rates of the primary end point for DES (5.0% vs 11.6%; hazard ration (HR) 0.64 [0.44-0.91]; P = .014). Rates of nonfatal myocardial infarction (1.2% vs 5.5%, hazard ration (HR) 0.44 [0.21-0.83]; P = .009), all-cause death (7.4% vs 14.4%; HR 0.7 [0.51-0.95]; P = .02), and target vessel revascularization (TVR) (2.3% vs 6.2%; HR 0.59 [0.34-0.99]; P = .046) were also lower, whereas stent thrombosis and bleeding rates were similar. In contrast, among patients <75 years (n = 1,909), the only significant benefit of DES was a reduced rate of TVR (4.0% vs 8.7%, HR 0.66 [0.55-0.80]; P < .0001).

CONCLUSIONS

In patients ≥75 years requiring large (≥3.0 mm) coronary stents, use of DES was beneficial compared with BMS and reduced the rate of ischemic events, mortality, and TVR. These data suggest that DES should be preferred over BMS in elderly patients.

Comparison among patients≥75 years having percutaneous coronary angioplasty using drug-eluting stents versus bare metal stents

Limited data are available on long-term efficacy and safety of drug-eluting stents (DES) in elderly patients who underwent PCI. A total of 635 consecutive patients aged ≥75 years who underwent PCI were enrolled at 2 European centers. Of these, 170 patients received at least 1 DES, whereas 465 patients received bare metal stent (BMS) only. Primary end point was the incidence of net adverse clinical events (NACE), defined as the occurrence of ischemic events or bleeding events, and was compared at a median follow-up of 31.2 months. Clinical follow-up information was available in 593 patients (93.4%). The duration of dual antiplatelet therapy was 12.3±5.1 months in the DES group and 3.8±7.4 months in the BMS group. The Kaplan-Meier estimate of NACE at 5 years was significantly lower in DES-treated patients (40.5%) than in BMS-treated patients (55.7%; p=0.009). This benefit was driven by a significant reduction in myocardial infarction (8.6% vs 16.6%; p=0.038) and target vessel revascularization rates (7.9% vs 21.9%; p=0.003) in the DES group, with no significant increase in the incidence of bleeding events (13.8% vs 12.2%; p=0.882). These results were confirmed at propensity score-adjusted Cox proportional hazard analysis. In conclusion, in patients≥75 years, the use of DES compared with BMS seems to reduce myocardial infarction and repeat revascularization rates at long-term follow-up, without an increase in bleeding despite longer duration of dual antiplatelet therapy. This net clinical benefit, resulting from persistent efficacy and safety over time, may support the use of DES as a reasonable option in patients≥75 years.