Drug-eluting stents: a study of international practice

Do responses to news matter? Evidence from interventional cardiology

We examine physician responses to a global information shock and how these impact their patients. We exploit international news over the safety of an innovation in healthcare, the drug-eluting stent. We use data on interventional cardiologists' use of stents to define and measure cardiologists' responsiveness to the initial positive news and link this to their patients' outcomes. We find substantial heterogeneity in responsiveness to news. Patients treated by cardiologists who respond slowly to the initial positive news have fewer adverse outcomes. This is not due to patient-physician sorting. Instead, our results suggest that the differences are partially driven by slow responders being better at deciding when (not) to use the new technology, which in turn affects their patient outcomes.

Temporal trends in percutaneous coronary intervention in Australia: A retrospective analysis from 2000-2021

OBJECTIVE

The aim of this study was to describe the trend in percutaneous coronary intervention (PCI) with insertion of a stent in Australia from 2000/01 to 2020/21 and investigate trends in same-day versus non-same-day discharge following PCI. A secondary aim was to compare the rate of coronary artery bypass grafting (CABG) with PCI procedures, while a third aim was to compare marked PCI trend changes with the PCI guidelines during the study period.

BACKGROUND

PCI with stent deployment is the most common form of interventional treatment for coronary artery disease, and its use has been expanding since 2000. However, there is a lack of descriptive studies of the national trend in Australia.

METHODS

All procedures for PCI and CABG were extracted across 21 years (2000/01 to 2020/21) from the Australian Institute of Health and Welfare data. Age-standardized rates were calculated using the Australian standard population as of June 2001. The ratio of PCI to CABG procedures was also calculated. Trends for PCI were stratified by age, gender, and same-day or overnight discharge episodes. Linear regression analysis was done to compare the age-standardized rates across different age categories. Segmented regression analysis was performed to ascertain the change in the age-standardized rates of PCI during the study period. Whether the changepoints in the trend were matched with guideline updates was also assessed.

RESULTS

There were 751 728 PCI procedures in persons aged 30 years and above between 2000/01 and 2020/21. The age-standardized rate for the study period showed that persons aged 60-74 years had a higher rate of procedures (102.7) compared to persons aged 30-59 years (81.3) and 75 years and older (61.8) (P < 0.001). There were two statistically significant changepoints in the overall trend; 2005/06 and 2013/14, matched with the change in PCI guidelines. Despite the lower number of procedures for same-day discharge episodes, there has been an increasing trend since 2014/15. More than two-thirds of all stenting procedures were the insertion of a single stent. PCI to CABG procedure ratio increased from 0.6 in 2000/01 to 1.8 in 2020/21.

CONCLUSIONS

There was a varying trend in the age-standardized rate of PCI with a peak in 2005/06. The trend appears to be stabilizing in the later part of the study period, but the rate for same-day discharge episodes showed an increasing trend after 2014/15. There is consistency with changepoints in the trend and updated PCI guideline recommendations. The ratio of PCI with insertion of a stent to CABG procedure increased substantially across the study period.

Temporal trends in percutaneous coronary interventions thru the drug eluting stent era: Insights from 18,641 procedures performed over 12-year period

BACKGROUND

The last decade, regarded as the DES era in PCI, has witnessed significant advances in the management of coronary disease. We aimed to assess temporal trends in the practice and outcome of percutaneous coronary intervention (PCI) during the drug eluting stent (DES) era.

METHODS

We analyzed 18,641 consecutive PCI's performed between January 2004 and December 2016, distinguished by procedural date (Q₁ : 2004-2006, n = 4,865; Q₂ : 2007-2009, n = 4,977; Q₃ : 2010-2012, n = 4,230; Q₄ : 2013-2016, n = 4,569).

RESULTS

At presentation, mean patients age was 65 (±11) years and 22.8% were females. Over time, there was a rise in the relative number of octogenarians (Q₁ : 10.7% vs Q₄ : 15.5%, P < 0.001) and an increase in the burden of most comorbidities (e.g., left ventricular dysfunction ≥ moderate and chronic kidney disease, P < 0.001 for both). Despite a 2-fold increase in the rate of complex interventions, and a 3-fold increase in the rate of unprotected left-main angioplasty (P < 0.001 for both), the radial approach was increasingly adopted (Q₁ : 2% to Q₄ : 63.5%, P < 0.001). DES implantation increased from 43% to 83% at the expense of bare metal stent (BMS) application, and accompanied by drug coated balloon sprout to 1.8%, P < 0.001. Kaplan-Meier survival curves revealed a time-based enhanced outcome, with a decreased rate of death, MI, target vessel revascularization and CABG over the years.

CONCLUSIONS

In the last decade, PCI has evolved to offer better outcome to more elderly, sicker patient population, with more complex coronary disease interventions. The shift to second generation DES and to enhanced PCI techniques may explain part of this progress.

Trends in hospital discharges, management and in-hospital mortality from acute myocardial infarction in Switzerland between 1998 and 2008

Background

Since the late nineties, no study has assessed the trends in management and in-hospital outcome of acute myocardial infarction (AMI) in Switzerland. Our objective was to fill this gap.

Methods

Swiss hospital discharge database for years 1998 to 2008. AMI was defined as a primary discharge diagnosis code I21 according to the ICD10 classification. Invasive treatments and overall in-hospital mortality were assessed.

Results

Overall, 102,729 hospital discharges with a diagnosis of AMI were analyzed. The percentage of hospitalizations with a stay in an Intensive Care Unit decreased from 38.0% in 1998 to 36.2% in 2008 (p for trend < 0.001). Percutaneous revascularizations increased from 6.0% to 39.9% (p for trend < 0.001). Bare stents rose from 1.3% to 16.6% (p for trend < 0.001). Drug eluting stents appeared in 2004 and increased to 23.5% in 2008 (p for trend < 0.001). Coronary artery bypass graft increased from 1.0% to 3.0% (p for trend < 0.001). Circulatory assistance increased from 0.2% to 1.7% (p for trend < 0.001). Among patients managed in a single hospital (not transferred), seven-day and total in-hospital mortality decreased from 8.0% to 7.0% (p for trend < 0.01) and from 11.2% to 10.1%, respectively. These changes were no longer significant after multivariate adjustment for age, gender, region, revascularization procedures and transfer type. After multivariate adjustment, differing trends in revascularization procedures and in in-hospital mortality were found according to the geographical region considered.

Conclusion

In Switzerland, a steep rise in hospital discharges and in revascularization procedures for AMI occurred between 1998 and 2008. The increase in revascularization procedures could explain the decrease in in-hospital mortality rates.

Survival Benefit With Drug-Eluting Stents in Observational Studies

Background—

Recently, there has been increased interest in leveraging observational studies for comparative effectiveness research. Without robust and valid risk adjustment, however, findings from these nonrandomized studies may remain biased. Previous studies examining long-term mortality with drug-eluting stents (DESs) have demonstrated discordant results between randomized trials and observational studies. To examine the impact of treatment selection bias on these findings, we used data from a prospective percutaneous coronary intervention (PCI) registry (EVENT [Evaluation of Drug Eluting Stents and Ischemic Events]) to compare clinical outcomes between DESs and bare metal stents (BMSs) using conventional (multivariable regression and propensity matching) and novel (instrumental variable analysis) risk-adjustment techniques.

Methods and Results—

The study population consisted of 9266 patients who underwent nonemergent PCI with stent placement at 55 US centers between 2004 and 2007. All-cause mortality and target lesion revascularization (TLR) were assessed prospectively over 1 year of follow-up. Overall, 8171 patients (88%) received DES, but this proportion substantially differed by treatment year (93% in 2004–2006 and 73% in 2007; P <0.001). One-year rates of death and TLR were significantly lower with DES versus BMS (death, 2.5% versus 5.6%; TLR, 4.2% versus 6.9%; P <0.001 for both), findings that persisted in both multivariable-adjusted and propensity-matched analyses. In contrast, instrumental variable analysis, using enrollment period (2004–2006 versus 2007) as the instrument, demonstrated no significant difference in 1-year mortality (predicted absolute difference, 2.0%; 95% CI, -1.8% to 5.7%; P =0.30) and a strong trend toward reduced TLR with DES use (predicted absolute difference, -4.2%; 95% CI, -8.8% to 0.4%; P =0.07).

Conclusions—

Among unselected PCI patients in contemporary practice, DES use tended to be associated with a consistent reduction in TLR regardless of risk-adjustment method but showed discordant effects on mortality with conventional risk adjustment compared with instrumentable variable analysis. These findings underscore the limitations of standard risk-adjustment methods to adequately address treatment selection bias in nonrandomized studies and have important implications for comparative effectiveness research using observational data.

Mode of death after contemporary percutaneous coronary intervention: a report from the Evaluation of Drug Eluting Stents and Ischemic Events registry

BACKGROUND

When selecting clinical trial end points, some investigators prefer cardiovascular death (CVD) while others believe that all-cause mortality is more relevant. However, the relative contribution of CVD to 1-year mortality after contemporary percutaneous coronary intervention (PCI) is not known.

METHODS

We evaluated the mode of death (MOD) in EVENT, a prospective PCI registry at 55 US hospitals. Vital status was assessed at 6 and 12 months as part of the study protocol, and MOD was independently reviewed in blinded fashion.

RESULTS

Between 2004 and 2007, EVENT enrolled 10,144 patients of whom 295 (2.9%) died within the first year: 51 (17%) ≤30 days; and 244 (83%) between 31 and 365 days after index PCI. Overall, CVD accounted for 42% of deaths, and no clear cause could be identified in a substantial subgroup (25% of deaths). Among patients who died ≤30 days, the MOD was more likely to be CVD (odds ratio 3.96, 95% CI 2.08-7.55), whereas the incidence of CVD and non-CVD was similar after 30 days. Findings were similar after a series of sensitivity analyses including reassignment of unknown MOD to the CVD category, using multiple imputation modeling, or when evaluating MOD in prespecified subgroups of patients with diabetes, acute coronary syndromes, or left ventricular dysfunction.

CONCLUSIONS

Among unselected PCI patients, 1-year mortality is approximately 3%, and CVD is confirmed in <50% of all deaths. Regardless of analytic approach, CVD is the primary contributor to overall mortality during the first 30 days after PCI, whereas rates of CVD and non-CVD are remarkably similar after the first month after PCI.

Long-term mortality of coronary artery bypass grafting and bare-metal stenting

BACKGROUND

There is little information on relative survival with follow-up longer than 5 years in patients undergoing coronary artery bypass grafting (CABG) and patients undergoing percutaneous coronary intervention (PCI) with stenting. This study tested the hypothesis that CABG is associated with a lower risk of long-term (8-year) mortality than is stenting with bare-metal stents for multivessel coronary disease.

METHODS

We identified 18,359 patients with multivessel disease who underwent isolated CABG and 13,377 patients who received bare-metal stenting in 1999 to 2000 in New York and followed their vital status through 2007 using the National Death Index (NDI). We matched CABG and stent patients on the number of diseased coronary vessels, proximal left anterior descending (LAD) artery disease, and propensity of undergoing CABG based on numerous patient characteristics and compared survival after the 2 procedures.

RESULTS

In the 7,235 pairs of matched patients, the overall 8-year survival rates were 78.0% for CABG and 71.2% for stenting (hazard ratio [HR], 0.68; 95% confidence interval [CI], 0.64 to 0.74; p < 0.001). For anatomic groups classified by the number of diseased vessels and proximal LAD involvement, the HRs ranged from 0.53 (p < 0.001) for patients with 3-vessel disease involving proximal LAD artery disease to 0.78 (p = 0.05) for patients with 2-vessel disease but no disease in the LAD artery. A lower risk of death after CABG was observed in all subgroups stratified by a number of baseline risk factors.

CONCLUSIONS

Coronary artery bypass grafting is associated with a lower risk of death than is stenting with bare metal stents for multivessel coronary disease.

Impact of incomplete revascularization on long-term mortality after coronary stenting

BACKGROUND

The impact of incomplete revascularization (IR) on adverse outcomes after percutaneous coronary intervention remains inconclusive, and few studies have examined mortality during follow-ups longer than 5 years. The objective of this study is to test the hypothesis that IR is associated with higher risk of long-term (8-year) mortality after stenting for multivessel coronary disease.

METHODS AND RESULTS

A total of 13 016 patients with multivessel disease who had undergone stenting procedures with bare metal stents in 1999 to 2000 were identified in the New York State's Percutaneous Coronary Intervention Reporting System. A logistic regression model was fit to predict the probability of achieving complete revascularization (CR) in these patients using baseline risk factors; then, the CR patients were matched to the IR patients with similar likelihoods of achieving CR. Each patient's vital status was followed through 2007 using the National Death Index, and the difference in long-term mortality between IR and CR was compared. It was found that CR was achieved in 29.2% (3803) of the patients. For the 3803 pair-matched patients, the respective 8-year survival rates were 80.8% and 78.5% for CR and IR (P=0.04), respectively. The risk of death was marginally significantly higher for IR (hazard ratio=1.12; 95% confidence interval, 1.01-1.26, P=0.04). The 95% bootstrap confidence interval for the hazard ratio was 0.98 to 1.32.

CONCLUSIONS

IR may be associated with higher risk of long-term mortality after stenting with BMS in patients with multivessel disease. More prospective studies are needed to further test this association.

Thirty-day in-hospital revascularization and mortality rates after acute myocardial infarction in seven Canadian provinces

BACKGROUND

Recent clinical trials have demonstrated benefit with early revascularization following acute myocardial infarction (AMI). Trends in and the association between early revascularization after (ie, 30 days or fewer) AMI and early death were determined.

METHODS AND RESULTS

The Statistics Canada Health Person-Oriented Information Database, consisting of hospital discharge records for seven provinces from the Canadian Institute for Health Information Hospital Morbidity Database, was used. If there was no AMI in the preceding year, the first AMI visit within a fiscal year for a patient 20 years of age or older was included. Times to death in hospital and to revascularization procedures were counted from the admission date of the first AMI visit. Mixed model regression analyses with random slopes were used to assess the relationship between early revascularization and mortality. The overall rate of revascularization within 30 days of AMI increased significantly from 12.5% in 1995 to 37.4% in 2003, while the 30-day mortality rate decreased significantly from 13.5% to 10.6%. There was a linearly decreasing relationship - higher regional use of revascularization was associated with lower mortality in both men and women.

CONCLUSIONS

These population-based utilization and outcome findings are consistent with clinical trial evidence of improved 30-day in-hospital mortality with increased early revascularization after AMI.

Local arterial nanoparticle delivery of siRNA for NOX2 knockdown to prevent restenosis in an atherosclerotic rat model

Both atherosclerosis and arterial interventions induce oxidative stress mediated in part by nicotinamide adenine dinucleotide phosphate (NADPH) oxidases that have a pivotal role in the development of neointimal hyperplasia and restenosis. For small interfering RNA (siRNA) targeting of the NOX2 (Cybb) component of the NADPH oxidase to prevent restenosis, gene transfer with viral vectors is effective, but raises safety issues in humans. We developed a new approach using the amino-acid-based nanoparticle HB-OLD7 for local delivery of siRNA targeting NOX2 to the arterial wall. siRNA-nanoparticle complexes were transferred into the regional carotid artery walls after angioplasty in an atherosclerotic rat model. Compared with angioplasty controls, Cybb gene expression (measured by quantitative reverse transcriptase-PCR) in the experimental arterial wall 2 weeks after siRNA was reduced by >87%. The neointima-to-media-area ratio was decreased by >83%, and the lumen-to-whole-artery area ratio was increased by >89%. Vital organs showed no abnormalities and splenic Cybb gene expression showed no detectable change. Thus, local arterial wall gene transfer with HB-OLD7 nanoparticles provides an effective, nonviral system for efficient and safe local gene transfer in a clinically applicable approach to knock down an NADPH oxidase gene. Local arterial knockdown of the Cybb gene significantly inhibited neointimal hyperplasia and preserved the vessel lumen without systemic toxicity.