A comparison of clinical outcomes from carotid artery stenting among US hospitals

Effects of different positions of intravascular stent implantation in stenosed vessels on in-stent restenosis: An experimental and numerical simulation study

Percutaneous coronary intervention (PCI) has been widely used in the treatment of atherosclerosis, while in-stent restenosis (ISR) has not been completely resolved. Studies have shown that changes in intravascular mechanical environment are related to ISR. Hence, an in-depth understanding of the effects of stent intervention on vascular mechanics is important for clinically optimizing stent implantation and relieving ISR. Nine rabbits with stenotic carotid artery were collected by balloon injury. Intravascular stents were implanted into different longitudinal positions (proximal, middle and distal relative to the stenotic area) of the stenotic vessels for numerical simulations. Optical coherence tomography (OCT) scanning was performed to reconstruct the three-dimensional configuration of the stented carotid artery and blood flow velocity waveforms were collected by Doppler ultrasound. The numerical simulations were performed through direct solution of Naiver-Stokes equation in ANSYS. Results showed that the distributions of time-averaged wall shear stress (TAWSS), oscillating shear index (OSI) and relative residual time (RRT) in near-end segment were distinctively different from other regions of the stent which considered to promote restenosis for all three models. Spearman rank-correlation analysis showed a significant correlation between hemodynamic descriptors and the stent longitudinal positions (r_TAWSS = -0.718, r_OSI = 0.898, r_RRT = 0.818, p < 0.01). Histology results of the near-end segment showed neointima thickening deepened with the longitudinal positions of stent which was consistent with the numerical simulations. The results suggest that stent implantation can promote restenosis at the near-end segment. As the stenting position moves to distal end, the impact on ISR is more significant.

The Potential Impact of "Take the Volume Pledge" on Outcomes After Carotid Artery Stenting

BACKGROUND

The "Volume Pledge" aims to centralize carotid artery stenting (CAS) to hospitals and surgeons performing ≥10 and ≥5 procedures annually, respectively.

OBJECTIVE

To compare outcomes after CAS between hospitals and surgeons meeting or not meeting the Volume Pledge thresholds.

METHODS

We queried the Nationwide Inpatient Sample for CAS admissions. Hospitals and surgeons were categorized as low volume and high volume (HV) based on the Volume Pledge. Multivariable hierarchical regression models were used to examine the impact of hospital volume (2005-2011) and surgeon volume (2005-2009) on perioperative outcomes.

RESULTS

Between 2005 and 2011, 22 215 patients were identified. Most patients underwent CAS by HV hospitals (86.4%). No differences in poor outcome (composite endpoint of in-hospital mortality, postoperative neurological or cardiac complications) were observed by hospital volume but HV hospitals did decrease the likelihood of other complications, nonroutine discharge, and prolonged hospitalization. From 2005 to 2009, 9454 CAS admissions were associated with physician identifiers. Most patients received CAS by HV surgeons (79.2%). On multivariable analysis, hospital volume was not associated with improved outcomes but HV surgeons decreased odds of poor outcome (odds ratio [OR] 0.76, 95% confidence interval [CI] 0.59-0.97; P = .028), complications (OR 0.56, 95% CI 0.46-0.71, P < .001), nonroutine discharge (OR 0.70, 95% CI 0.57-0.87; P = .001), and prolonged hospitalization (OR 0.52, 95% 0.44-0.61, P < .001).

CONCLUSION

Most patients receive CAS by hospitals and providers meeting the Volume Pledge threshold for CAS. Surgeons but not hospitals who met the policy's volume standards were associated with superior outcomes across all measured outcomes.

Snapshot of current carotid artery stenting practice and accreditation in the USA

Objective

The aim of this exploratory study was to compare the performance of carotid artery stenting (CAS) best practices between Intersocietal Accreditation Commission (IAC) accredited facilities and non-accredited facilities certified by the Centers for Medicare and Medicaid Services (CMS).

Methods

A random, anonymous survey was sent to CMS and IAC accredited facilities querying facility routine performance of 16 CAS procedure components found in published guidelines and utilised during clinical trials.

Results

There were 28 responses (response rate=17%). Significant differences were found between the CMS and the IAC facilities for four of 16 procedure measures: determination of modified Rankin Scale score prior to stenting (p=0.012, 95% CI 20% to 80%), accurate measurement of per cent stenosis using electronic callipers (p=0.005, 95% CI 24% to 84%), confirmation of anticoagulation with activated clotting time greater than 250 s prior to crossing the lesion (p=0.03, 95% CI 7% to 69%), and comparison of facility outcomes to accepted benchmarks for stroke and death (p=0.03, 95% CI 7% to 69%). Overall, IAC facilities performed all 16 procedures more frequently (97%) than CMS facilities (66%) (p<0.001, 95% CI 24% to 36%).

Conclusions

Although the sample size was small, the results demonstrated IAC accredited facilities are more likely to follow best practices, to use quantitative tools to select appropriate patients, and quantitively measure patient-centred clinical outcomes compared with CMS certified facilities. The findings raise the question as to the value of CMS certification versus IAC accreditation as a requirement for reimbursement.

Differences of in-hospital outcomes within patients undergoing percutaneous coronary intervention at institutions with high versus low procedural volume: a report from the Japanese multicentre percutaneous coronary intervention registry

Objective

We aimed to determine the relationship between the prevalence of in-hospital complications and annual institutional patient volume in a population of patients undergoing percutaneous coronary intervention (PCI).

Methods

Clinical data of patients receiving PCI between January 2010 and June 2015 were collected from 14 academic institutions in the Tokyo area and subsequently used for analysis. We employed multivariate hierarchical logistic regression models to determine the effect of institutional volume on several in-hospital outcomes, including in-hospital mortality and procedure-related complications.

Results

A total of 14 437 PCI cases were included and categorised as receiving intervention from either lower-volume (<200 procedures/year, n=6 hospitals) or higher-volume (≥200 procedures/year, n=8 hospitals) institutions. Clinical characteristics differed significantly between the two patient groups. Specifically, patients treated in higher-volume hospitals presented with increased comorbidities and complex coronary lesions. Unadjusted mortality and complication rate in lower-volume and higher-volume hospitals were 1.3% and 1.2% (p=0.0614) and 6.2% and 8.1% (p=0.001), respectively. However, multivariate hierarchical logistic regression models adjusting for differences in the patient characteristics demonstrated that institutional volume was not associated with adverse clinical outcomes.

Conclusions

In conclusion, we observed no significant association between annual institutional volume and in-hospital outcomes within the contemporary PCI multicentre registry.

Trial registration number

UMIN R000005598.

Significant Association of Annual Hospital Volume With the Risk of Inhospital Stroke or Death Following Carotid Endarterectomy but Likely Not After Carotid Stenting

Background—

Associations between hospital volume and the risk of stroke or death following carotid endarterectomy (CEA) and carotid artery stenting (CAS) on a national level in Germany were analyzed.

Methods and Results—

Secondary data analysis using microdata from the nationwide statutory German quality assurance database on all surgical or endovascular carotid interventions on the extracranial carotid artery between 2009 and 2014. Hospitals were categorized into empirically determined quintiles according to the annual case volume. The resulting volume thresholds were 10, 25, 46, and 79 for CEA and 2, 6, 12, and 26 for CAS procedures. The primary outcome was any stroke or death before hospital discharge. For risk-adjusted analyses, a multilevel regression model was applied. The analysis included 161 448 CEA and 17 575 CAS procedures. In CEA patients, the crude risk of stroke or death decreased monotonically from 4.2% (95% confidence interval, 3.6%–4.9%) in low-volume hospitals (first quintile 1–10 CEA per year) to 2.1% (2.0%–2.2%) in hospitals providing ≥80 CEA per year (fifth quintile; P <0.001 for trend). The overall risk of any stroke or death in CAS patients was 3.7% (3.5%–4.0%), but no trend on annual volume was seen ( P =0.304). Risk-adjusted analyses confirmed a significant inverse relationship between hospital volume (categorized or continuous) and the risk of stroke or death after CEA but not CAS procedures.

Conclusions—

An inverse volume–outcome relationship in CEA-treated patients was demonstrated. No significant association between hospital volume and the risk of stroke or death was found for CAS.