Late stent thrombosis: considerations and practical advice for the use of drug-eluting stents: a report from the Society for Cardiovascular Angiography and Interventions Drug-eluting Stent Task Force

White thrombi on optical coherence tomography after rotational atherectomy of severely calcified coronary lesions

PURPOSE

Rotational atherectomy (RA) has improved percutaneous treatment of severely calcified coronary lesions, but the "no-reflow" phenomenon remains a serious complication. Platelet activation by RA may contribute to no-reflow, and the use of optical coherence tomography (OCT) to test the effect of RA on white thrombus could confirm platelet activation indirectly.

METHODS

We analyzed 53 consecutive patients with severely calcified lesions on coronary angiography. All patients were examined with OCT. In total, 20 patients who received RA and for whom OCT imaging was performed before and after RA and stent implantation comprised the RA group. The remaining 33 patients formed the control group, for whom OCT imaging was performed before balloon dilatation and after stent implantation.

RESULTS

The patients in the RA group were older and had a higher incidence of diabetes mellitus. In the control group, there was no thrombogenesis during the procedure, whereas in the RA group, all the target vessels had white thrombi on OCT after RA. The average number of white thrombi per lesion after RA was 7.23 ± 4.4, and the average length of white thrombus was 0.51 ± 0.33 mm. Statistical analysis with Pearson's correlation coefficient showed that thrombus load was related to burr size (r = 0.575, p = 0.040) and number of rotations (r = 0.599, p = 0.031).

CONCLUSION

White thrombi during RA can be verified by performing OCT. Treating calcified lesions with RA may enhance thrombogenesis. These data suggest using appropriate therapy to avoid no-reflow during RA.

Comparison of bailout and planned rotational atherectomy for severe coronary calcified lesions

Background

To compare outcomes of bailout and planned rotational atherectomy (RA) in the treatment of severe calcified coronary lesions.

Methods

Data of patients treated with RA from 2017 to 2018 at a single-center registry were retrospectively analyzed. All patients were divided into planned RA and bailout RA groups, data between two groups were compared.

Results

A total of 190 patients were included in this study, 138 patients received planned RA and 52 patients received bailout RA. Baseline clinical characteristics had no significant differences between groups. The number of implanted stents and total stents length were similar. But the number of balloon (1.6 ± 0.8 vs. 2.7 ± 1.3, P < 0.001), procedure time (83.5 ± 26.2 vs. 100.8 ± 36.4 min, P = 0.007), fluoroscopy volume (941 ± 482 vs. 1227 ± 872 mGy, P = 0.012] and contrast amount (237 ± 62 vs. 275 ± 90 ml, P = 0.003) were all lower in planned RA group. Planned RA had a higher procedural success rate (99.3% vs. 92.3%, P = 0.007) and a lower complication incidence (4.3% vs. 17.3%, P = 0.009). But the primary outcomes at 3 years (9.2 and 16.6%, log rank p = 0.24) had no difference between groups.

Conclusions

For severe coronary artery calcification, although planned RA did not improved the long term prognosis compared with bailout RA, but it can improve the immediate procedural success rate, reduce the incidence of complications, the procedure time and the volume of contrast.

Early determination of clopidogrel responsiveness by platelet reactivity index identifies patients at risk for cardiovascular events after myocardial infarction

While acute myocardial infarction (MI) is associated with impaired clopidogrel responsiveness, systematic evaluation is lacking due to the inability of functional aggregation-based assays to analyse clopidogrel responsiveness in the presence of glycoprotein IIb/IIIa inhibitors. Using the P2Y12-specific, non-aggregation-based platelet-reactivity-index (PRI) we assessed clopidogrel responsiveness in patients with acute MI. Clopidogrel responsiveness was determined 24 hours (h) after loading with 600 mg clopidogrel in 54 patients with acute MI admitted for coronary intervention. A PRI > 50% was considered as suboptimal inhibition. Overall response in MI patients was suboptimal with a median PRI of 58%. Diabetes, low high-density lipoprotein and pre-hospital clopidogrel loading were associated with impaired clopidogrel responsiveness. Patients loaded at first medical contact had a significantly weaker platelet inhibition by clopidogrel after 24 h (PRI 63%) compared to those loaded peri-interventionally (PRI 54%, p=0.014). Clinical outcome was assessed as a combination of cardiac death, non-fatal MI, stent thrombosis, ischaemic stroke, and urgent target vessel revascularisation after 12 months. The pre-selected cut-off of PRI ≤ 50% yielded a sensitivity of 87% at a specificity of 26%, whereas a PRI ≤ 57% determined by receiver-operating characteristics (ROC)-analysis yielded a sensitivity of 80% at a specificity of 56% (event rate: PRI ≤ 57%: 12.0%; PRI > 57%: 41.4%, p=0.0136). In conclusion, PRI detects clopidogrel responsiveness in acute MI patients requiring glycoprotein IIb/IIIa antagonism; and impaired clopidogrel responsiveness predisposes to clinical events. Pre-hospital clopidogrel loading was associated with impaired response and more adverse events challenging the concept of earliest oral clopidogrel loading in MI patients.

Rate of percutaneous coronary intervention for the management of acute coronary syndromes and stable coronary artery disease in the United States (2007 to 2011)

Although the benefit of percutaneous coronary interventions (PCIs) for patients presenting with acute coronary syndromes (ACS) has been established in numerous studies, the role of PCI in stable coronary artery disease (CAD) remains controversial. With the publication of the Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluations trial and the appropriate use criteria for coronary artery revascularization, we sought to examine the impact of these treatment strategies and guidelines on the current practice of PCI in United States. We conducted a serial cross-sectional study with time trends of patients undergoing PCI for ACS and stable CAD from 2007 to 2011. The annual rate of all PCI decreased by 27.7% from 10,785 procedures per million adults per year in 2007 to 2008 to 7,801 procedures per million adults per year in 2010 to 2011 (p=0.03). Although there was no statistically significant decrease in the PCI utilization for ACS from 2007 to 2011, PCI utilization for stable CAD decreased by 51.7% (from 2,056 procedures per million adults per year in 2008 to 992 procedures per million adults per year in 2011, p=0.02). Hospitals with a higher volume of PCI experienced a more significant decrease. Decrease in PCI utilization for stable CAD was statistically significant for patients with Medicare and private insurance/health maintenance organization (44.5%, p=0.03 and 59.5%, p=0.007, respectively). In conclusion, the rate of PCI decreased substantially starting from 2009 in the United States. Most of the decrease was attributed to the reduction in PCI utilization for stable CAD.

Usefulness of postmarket studies to evaluate long-term safety of coronary eluting stents (from the ENDEAVOR and PROTECT Programs)

Differences in enrollment criteria and protocol requirements are believed to affect patient representation and outcomes from premarket and postmarket surveillance (PMS) trials. These differences have not been assessed in studies evaluating coronary stenting. We aimed to assess differences in clinical profile and long-term outcomes in patients enrolled into premarket versus PMS trials assessing the Endeavor zotarolimus-eluting stent (E-ZES). We pooled patient-level data for 2,132 and 4,357 E-ZES-treated subjects enrolled into the ENDEAVOR program (premarket) and Patient Related OuTcomes with Endeavor versus Cypher stenting Trial (PMS), respectively. Follow-up data were available through 3 years. Baseline characteristics and outcomes of patients enrolled in the 2 groups were compared. Propensity score-adjusted Cox proportional hazards models were used to assess the effect of differences in baseline characteristics. We also adjusted for protocol-mandated repeat angiography to account for differences in follow-up requirements. Despite significant differences in baseline characteristics, the unadjusted 3-year rates of major adverse cardiac events, major adverse cardiac and cerebrovascular events, and target vessel failure were similar (premarket vs PMS: 11.9% vs 12.7%, p = 0.369; 12.7% vs 13.9%, p = 0.191; and 13.8% vs 13.4%, p = 0.667, respectively). However, PMS trials had significantly higher rates of myocardial infarctions (p = 0.005) and definite or probable stent thrombosis (p = 0.016). After propensity score adjustment, myocardial infarction rates remained significantly different (hazard ratio 0.53, 95% confidence interval 0.30 to 0.91). To conclude, premarket and PMS trials assessing E-ZES implantation enrolled different patients. PMS trials were shown to be essential for the detection of safety signals.

The risk of endoscopic mucosal resection in the setting of clopidogrel use

Objective. Guidelines on antiplatelet medication use during endoscopy are based on limited evidence. We investigate the risk of bleeding and ischemic events in patients undergoing endoscopic mucosal resection (EMR) of esophageal lesions in the setting of scheduled cessation and prompt resumption of clopidogrel. Design. Single centre retrospective review. Patients. Patients undergoing EMR of esophageal lesions. Interventions. Use of clopidogrel before EMR and resumption after EMR. Patients cease antiplatelets and anticoagulants 7 days before EMR and resume clopidogrel 2 days after EMR in average risk patients. Main Outcomes. Gastrointestinal bleeding (GIB) and ischemic events (IE) within 30 days of EMR. Results. 798 patients underwent 1716 EMR. 776 EMR were performed on patients on at least 1 antiplatelet/anticoagulant (APAC). 17 EMR were performed following clopidogrel cessation. There were 14 GIB and 2 IE. GIB risk in the setting of recent clopidogrel alone (0%) was comparable to those not on APAC (1.1%) (P = 1.0). IE risk on clopidogrel (6.3%) was higher than those not on APAC (0.1%) (P = 0.03). Limitations. Retrospective study. Conclusions. Temporary cessation of clopidogrel before EMR and prompt resumption is not associated with an increased risk of gastrointestinal bleeding but may be associated with increased ischemic events.

Everolimus-eluting stents versus sirolimus- or paclitaxel-eluting stents: two-year results from the Guthrie Health Off-Label Stent (GHOST) registry

OBJECTIVES

We sought to compare the safety and effectiveness of everolimus-eluting stents (EES) versus first generation drug-eluting stents (FG-DES; sirolimus-eluting stent [SES] or paclitaxel-eluting stent [PES]).

METHODS

In 2,126 patients undergoing percutaneous coronary intervention (PCI), we compared the 2-year incidence of stent thrombosis (ST) and target vessel revascularization (TVR) between the EES versus FG-DES groups. Secondary end-points included all-cause death, myocardial infarction (MI), death or MI, and major adverse cardiovascular events (MACE, including death, MI, ST, or TVR). Further, we evaluated these end-points in 2 propensity-matched subgroups: EES versus SES; EES versus PES.

RESULTS

Complete 2-year follow-up was available in 1,911 (90%) patients. Compared to FG-DES, implantation of EES was associated with trends towards lower ST (0.9% vs. 2.8%, P = 0.068) and TVR (3.8% vs. 7.2%, P = 0.052), which persisted after adjustment for baseline differences (for ST, adjusted hazard ratio, HR 0.32; 95% confidence interval, 95% CI 0.10-1.02, P = 0.053; for TVR, HR 0.40; 95% CI 0.22-0.75, P = 0.004). Compared to SES, EES implantation was associated with lower TVR and a trend towards lower ST. Compared to PES, EES implantation was associated with less ST and TVR and trends towards lower death/MI and MACE. In the EES group, no ST was seen after the first 3 months.

CONCLUSIONS

The use of EES compared to FG-DES appears to be associated with reductions in ST and TVR at 2-year follow-up. Improved outcomes with EES are observed in comparison with SES as well as PES.

Evaluating the impact of public health notification: Duke clopidogrel experience

BACKGROUND

Provider and public health interventions in the late 2006 sought to change the duration of clopidogrel use after drug-eluting stent (DES) implantation. We evaluated whether public health interventions were associated with changes in patient-reported clopidogrel use among DES patients.

METHODS AND RESULTS

We used interrupted time analyses to evaluate trends in duration of patient-reported clopidogrel use before, during, and after public and provider interventions. We included patients with significant coronary artery disease receiving an intracoronary stent between April 2004 and December 2007 at a single tertiary care center. The center supplemented national and regulatory messaging regarding the role of clopidogrel after DES implantation with direct-to-patient and to-their-provider notifications in December 2006. The combination of public and provider direct notification was associated with significant changes in the percent of DES patients reporting clopidogrel use at 6 months (16.55% increase, P=0.010) and 12 months (15.33% increase, P=0.004), but no change at 24-month follow-up (4.64, P=0.295). During the same period, there was no change in the percent of bare-metal stent patients reporting clopidogrel use at 6-month (-3.73%, 0.654), 12-month (-5.98%, P=0.389), and 24-month follow-up (-5.16, P=0.708). Although mortality rates through 24 months seemed to decrease between the pre- and postintervention periods, these changes were not significant (DES, P=0.086; bare-metal stent, P=0.296).

CONCLUSIONS

The combination of national scientific and regulatory messaging supplemented by local, personal communications to DES patients and their primary healthcare providers was associated with a significant increase in patient-reported clopidogrel use.

Coronary stent management in elective genitourinary surgery

What's known on the subject? and What does the study add? Withdrawal of dual antiplatelet therapy before the recommended, 12 months for drug-eluting stents and 1 month for bare-metal stents increases the rate of major adverse coronary events and mortality. However, in those undergoing surgery the risk of bleeding is increased substantially for those on antiplatelet agents. Successful management in patients with coronary stents who must undergo elective or non-elective urological surgery should be a multidisciplinary decision. This article reviews the literature and recommends a protocol for clinical management of patients undergoing urological procedures after coronary stent placement. To review the literature on coronary stents and genitourinary surgery and provide a protocol for perioperative. The keywords, 'elective surgery', 'aspirin', 'clopidogrel', 'guidelines for percutaneous coronary intervention', and 'antiplatelet therapy after coronary stent placement' were used to search PubMed for any relevant articles relating to coronary stents. Recommendations were made based on the whether the procedures patients were exposed to placed them at low-, moderate- or high-bleeding risk based on the extent of the procedure. All elective procedures should be delayed for 1 month after bare-metal stent placement and 1 year after drug-eluting stent placement. In patients classified as low risk (endoscopy and laser prostatectomy), aspirin should be continued throughout the perioperative period and dual antiplatelet therapy should continue 24-48 h postoperatively, if there is no concern for active bleeding. In those classified as moderate risk (scrotal procedures, transurethral resection of bladder tumours, transurethral resection of the prostate, urinary sphincter placement) dual antiplatelet therapy should be discontinued 5-7 days before the procedure and continued within 7 days after procedure, if there is no concern for active bleeding, in consultation with cardiology. In high-risk procedures (cystectomy, nephrectomy, prostatectomy, penile prosthesis placement) dual antiplatelet therapy should be discontinued 10 days before the procedure and continued postoperatively within 7-10 days of the procedure, when there is no longer a concern for active bleeding with the assistance of a cardiologist. Coronary artery disease is becoming more prominent in our society, increasing the use of coronary stents and antiplatelet agents. With the proposed protocol, it is safe to proceed with surgical intervention in those that have adequate stent endothelialisation.

In vivo study on the histocompatibility and degradation behavior of biodegradable poly(trimethylene carbonate-co-D,L-lactide)

The aim of this study was to explore the in vivo behavior and histocompatibility of poly(trimethylene carbonate-co-D,L-lactide) (PDLLA/TMC) and its feasibility of manufacturing cardiovascular stents. Copolymers with 50/50 molar ratio were synthesized by ring-opening polymerization with TMC and D, L-LA, or TMC and L-LA. Poly(L-lactide) (PLLA) was synthesized as a control. The films of the three polymers were implanted into 144 Wistar rats. At different time points of implantation, polymer films were explanted for the evaluation of degradation characteristics and histocompatibility using size exclusion chromatography , nuclear magnetic resonance , environmental scanning electron microscope , and optical microscope. Results showed that there were differences in the percentage of mass loss, molecular weight, shape and appearance changes, and inflammation cell counts between different polymers. With the time extended, the film's superficial structure transformed variously, which was rather obvious in the polymer of PDLLA/TMC. In addition, there were relatively lower inflammation cell counts in the PDLLA/TMC and poly(trimethylene carbonate-co-L-lactide) (PLLA/TMC) groups at different time points in comparison with those in the PLLA group. The differences were of statistical significance (P< 0.05) in the group of PDLLA/TMC vs. PLLA, and the group of PLLA/TMC vs. PLLA, but not within the PDLLA/TMC and PLLA/TMC groups (P> 0.05). These results suggested that the polymer of PDLLA/TMC (50/50) with favorable degradation performance and histocompatibility is fully biodegradable and suitable for manufacturing implanted cardiovascular stents.

Improved late clinical safety with zotarolimus-eluting stents compared with paclitaxel-eluting stents in patients with de novo coronary lesions: 3-year follow-up from the ENDEAVOR IV (Randomized Comparison of Zotarolimus- and Paclitaxel-Eluting Stents in Patients With Coronary Artery Disease) trial

OBJECTIVES

The increased frequency of very late (>1 year) stent thrombosis (VLST) has raised concerns with regard to the safety of sirolimus-eluting stents and paclitaxel-eluting stents (PES).

BACKGROUND

Experimental and preliminary clinical findings with the zotarolimus-eluting stent (ZES) have suggested a favorable safety profile.

METHODS

The ENDEAVOR IV (Randomized Comparison of Zotarolimus- and Paclitaxel-Eluting Stents in Patients With Coronary Artery Disease) trial is a single-blind randomized ZES versus PES clinical trial in 1,548 patients with de novo native coronary lesions; the primary end point-9-month target vessel failure-was previously reported, annual clinical follow-up is planned for 5 years, and this report describes the 3-year outcomes.

RESULTS

The ZES compared with PES reduced target vessel failure (12.3% vs. 15.9%, hazard ratio [HR]: 0.76, 95% confidence interval [CI]: 0.58 to 1.00, p = 0.049), myocardial infarctions (MI) (2.1% vs. 4.9%, HR: 0.44, 95% CI: 0.25 to 0.80, p = 0.005), and cardiac death plus MI (3.6% vs. 7.1%, HR: 0.52, 95% CI 0.32 to 0.82, p = 0.004). Although the overall 3-year rate of Academic Research Consortium definite/probable stent thrombosis did not differ significantly (1.1% vs. 1.7%, HR: 0.67, 95% CI 0.28 to 1.64, p = 0.380), VLST (between 1 and 3 years) was significantly reduced in ZES patients (1 event vs. 11 events; 0.1% vs. 1.6%, HR: 0.09, 95% CI: 0.01 to 0.71, p = 0.004). Ischemia-driven target lesion revascularization at 3 years was similar with ZES versus PES (6.5% vs. 6.1%, HR: 1.10, 95% CI: 0.73 to 1.65, p = 0.662).

CONCLUSIONS

Three-year follow-up results from the ENDEAVOR IV trial indicate similar antirestenosis efficacy but improved clinical safety associated with ZES compared with PES, due to significantly fewer peri-procedural and remote MIs associated with fewer VLST events. (A Randomized, Controlled Trial of the Medtronic Endeavor Drug [ABT-578] Eluting Coronary Stent System Versus the Taxus Paclitaxel-Eluting Coronary Stent System in De Novo Native Coronary Artery Lesions; NCT00217269).

Cobalt chromium coronary stents and drug-eluting stents in real practice

Cobalt chromium stents (CCS) are seldom compared to drug-eluting stents (DES) for coronary intervention in published clinical trials. We evaluated the daily usage patterns of CCS in comparison to DES unconstrained by eligibility criteria. We compared consecutive patients (n = 303) with de novo lesions treated exclusively with a CCS to 432 patients treated exclusively with a DES. Patients in the CCS group were older, frequently had heart failure, renal failure, prior coronary balloon angioplasty, prior stroke, more comorbidities, and more multivessel disease than the DES group. The DES group had longer and more type C and left anterior descending (LAD) coronary artery lesions. The in-hospital major adverse cardiac events (MACE; death, myocardial infarction, stroke and target lesion revascularization (TLR)) were similar. At 6 months, the cumulative rate of MACE was 12.9% in the CCS group and 5.6% in the DES group (P < 0.001), and this was driven by TLR. The rates of stent thrombosis were similar in CCS (0.9%) and DES (1.0%) patients. In conclusion, the CCS were used in clinically higher risk patients, while DES were used in more severely diseased coronary arteries. Drug-eluting stent use resulted in lower rates of clinically driven repeat revascularization with similar rates of death, MI, stroke, and stent thrombosis.

Late safety, efficacy, and cost-effectiveness of a zotarolimus-eluting stent compared with a paclitaxel-eluting stent in patients with de novo coronary lesions: 2-year follow-up from the ENDEAVOR IV trial (Randomized, Controlled Trial of the Medtronic Endeavor Drug [ABT-578] Eluting Coronary Stent System Versus the Taxus Paclitaxel-Eluting Coronary Stent System in De Novo Native Coronary Artery Lesions)

OBJECTIVES

The aim of this study was to assess, after 2 years of follow-up, the safety, efficacy, and cost-effectiveness of a zotarolimus-eluting stent (ZES) compared with a paclitaxel-eluting stent (PES) in patients with native coronary lesions.

BACKGROUND

Early drug-eluting stents were associated with a small but significant incidence of very late stent thrombosis (VLST), occurring >1 year after the index procedure. The ZES has shown encouraging results in clinical trials.

METHODS

The ENDEAVOR IV trial (Randomized, Controlled Trial of the Medtronic Endeavor Drug [ABT-578] Eluting Coronary Stent System Versus the Taxus Paclitaxel-Eluting Coronary Stent System in De Novo Native Coronary Artery Lesions), a randomized (1:1), single-blind, controlled trial (n = 1,548) compared ZES versus PES in patients with single de novo coronary lesions. Two-year follow-up was obtained in 96.0% of ZES and 95.4% of PES patients. The primary end point was target vessel failure (TVF), and safety end points included Academic Research Consortium-defined stent thrombosis. Economic end points analyzed included quality-adjusted survival, medical costs, and relative cost-effectiveness of ZES and PES.

RESULTS

The TVF at 2 years was similar in ZES and PES patients (11.1% vs. 13.1%, p = 0.232). There were fewer myocardial infarctions (MIs) in ZES patients (p = 0.022), due to fewer periprocedural non-Q-wave MIs and fewer late MIs between 1 and 2 years. Late MIs were associated with increased VLST (PES: 6 vs. ZES: 1; p = 0.069). Target lesion revascularization was similar comparing ZES with PES (5.9% vs. 4.6%; p = 0.295), especially in patients without planned angiographic follow-up (5.2% vs. 4.9%; p = 0.896). The cost-effectiveness of ZES and PES was similar.

CONCLUSIONS

After 2 years of follow-up, ZES demonstrated efficacy and cost-effectiveness comparable to PES, with fewer MIs and a trend toward less VLST. (The ENDEAVOR IV Clinical Trial: A Trial of a Coronary Stent System in Coronary Artery Lesions; NCT00217269).

A randomized comparison of the Endeavor zotarolimus-eluting stent versus the TAXUS paclitaxel-eluting stent in de novo native coronary lesions 12-month outcomes from the ENDEAVOR IV trial

OBJECTIVES

The ENDEAVOR IV (Randomized Comparison of Zotarolimus-Eluting and Paclitaxel-Eluting Stents in Patients with Coronary Artery Disease) trial evaluated the safety and efficacy of the zotarolimus-eluting stent (ZES) compared with the paclitaxel-eluting stent (PES).

BACKGROUND

First-generation drug-eluting stents have reduced angiographic and clinical restenosis, but long-term safety remains controversial. A second-generation drug-eluting stent, which delivers zotarolimus, a potent antiproliferative agent, via a biocompatible phosphorylcholine polymer on a cobalt alloy thin-strut stent has shown promising experimental and early clinical results.

METHODS

This is a prospective, randomized (1:1), single-blind, controlled trial comparing outcomes of patients with single de novo coronary lesions treated with ZES or PES. The primary end point was noninferiority of 9-month target vessel failure defined as cardiac death, myocardial infarction, or target vessel revascularization.

RESULTS

Among a total of 1,548 patients assigned to ZES (n = 773) or PES (n = 775), at 9 months, ZES was noninferior to PES with rates of target vessel failure 6.6% versus 7.1%, respectively (p(noninferiority) < or = 0.001). There were fewer periprocedural myocardial infarctions with ZES (0.5% vs. 2.2%; p = 0.007), whereas at 12 months, there were no significant differences between groups in rates of cardiac death, myocardial infarction, target vessel revascularization, or stent thrombosis. Although incidence of 8-month binary angiographic in-segment restenosis was higher in patients treated with ZES versus PES (15.3% vs. 10.4%; p = 0.284), rates of 12-month target lesion revascularization were similar (4.5% vs. 3.2%; p = 0.228), especially in patients without planned angiographic follow-up (3.6% vs. 3.2%; p = 0.756).

CONCLUSIONS

These findings demonstrate that ZES has similar clinical safety and efficacy compared with PES in simple and medium complexity single de novo coronary lesions. (ENDEAVOR IV Clinical Trial; NCT00217269).

Use of drug-eluting stents in patients with coronary artery disease and renal insufficiency

Renal insufficiency (RI) has been shown to be associated with increased major adverse cardiovascular events after percutaneous coronary intervention. We reviewed the impact of RI on the pathogenesis of coronary artery disease and outcomes after percutaneous coronary intervention in the form of drug-eluting stent (DES) implantation in these high-risk patients. We searched the English-language literature indexed in MEDLINE, Scopus, and EBSCO Host research databases from 1990 through January 2009, using as search terms coronary revascularization, drug-eluting stent, and renal insufficiency. Studies that assessed DES implantation in patients with various degrees of RI were selected for review. Most of the available data were extracted from observational studies, and data from randomized trials formed the basis of a post hoc analysis. The outcomes after coronary revascularization were less favorable in patients with RI than in those with normal renal function. In patients with RI, DES implantation yielded better outcomes than did use of bare-metal stents. Randomized trials are needed to define optimal treatment of these high-risk patients with coronary artery disease.

Gastrointestinal bleeding in percutaneous coronary intervention and acute coronary syndromes

The increasingly prevalent use of antithrombotic drug combinations and an aging population are resulting in growing rates of gastrointestinal bleeding (GIB). GIB is a serious condition in the setting of stable and acute coronary syndromes, associated with high rates of ischemic events. Physicians should be aware of GIB in high-risk populations, especially the elderly and patients with anemia. We discuss the risk of GIB in patients treated with different antiplatelet and antithrombotic medications and their combinations, factors associated with GIB, and its optimal management and prevention.

Perioperative handling of patients on antiplatelet therapy with need for surgery

The widespread use of metal stents and drug-eluting stents has shown the extent to which patients with unstable coronary perfusion depend on antiplatelet drugs, and how their risk of late thrombosis depends on the long-term use of agents such as clopidogrel. It has also been shown that the risk of surgical bleeding, if antiplatelet drugs are continued, is lower than that of coronary thrombosis if they are withdrawn. Thus, except for low-risk settings, the practice of withdrawing antiplatelet drugs 5-10 days prior to surgical procedures should be changed. The following suggestions are meant to provide a guideline in this respect. Most of the current surgical procedures may be performed while on low-dose aspirin treatment. Except when bleeding may occur in closed spaces (e.g. intracranial surgery, spinal surgery in the medullary canal, surgery of the posterior chamber of the eye) or where excessive blood loss is expected, where only clopidogrel should be discontinued; in all other cases the surgical procedures should be carried out in the presence of dual antiplatelet agents (if prescribed). Aspirin may be discontinued only in subjects at low risk of thrombosis, and at high risk of intraoperative bleeding. Operations associated with an expected excessive blood loss should be postponed unless vital. When prescribed for acute coronary syndrome or during stent re-endothelialization, clopidogrel should not be discontinued before a noncardiac procedure. For elective procedures, surgery should be postponed until the end of the indication for clopidogrel. After the operation, clopidogrel should be resumed within the 12-24 h. Cardiac procedures should be postponed for at least 4 days after clopidogrel withdrawal. The thrombotic risk of preoperative withdrawal of antiplatelet drugs overwhelms the benefit of regional or neuraxial blockade. Antiplatelet treatment replacement by heparin or low-molecular weight heparin does not provide protection against the risk of coronary artery or stent thrombosis. Haemostasis requires that at least 20% of circulating platelets have a normal function. As the effects of antiplatelet agents are not reversible by other drugs, fresh platelets are the only manner to rapidly restore normal haemostasis. Aprotinin decreases postoperative bleeding and transfusion rates in patients undergoing CABG and on clopidogrel during the days preceding surgery.

A novel system for the reconstruction of a coronary artery lumen profile in real time: a preclinical validation

Accurate sizing of vessel diameter is important for understanding the physiology of blood vessels as well as the treatment of coronary and peripheral artery disease. The objective of this study was to validate a novel catheter-based system [the LumenRECON (LR) system] for the real-time reconstruction of lumen cross-sectional area (CSA) along the length of a vessel segment. A total of 22 swine (20 Yorkshire and 2 atherosclerotic Ossabaw swine) were used to evaluate the accuracy, reproducibility, and safety of the system compared with intravascular ultrasound (IVUS). The CSA of the right coronary artery, left anterior descending coronary artery, and left circumflex artery were determined by IVUS and the LR system over a 3- to 4-cm segment in 12 Yorkshire and 2 atherosclerotic Ossabaw swine and 2 postmortem atherosclerotic human hearts. In eight chronic animals, the effect of the LR catheter on the vessel wall was evaluated at 1 day and 2 wk (4 animals each) after the intervention. A Bland-Altman plot of the LR and IVUS data showed a mean difference between the two measurements of 0.055 mm in diameter, which was not statistically significant from zero, indicating a lack of bias in the comparison of the LR system with IVUS. The root mean square error of the two measurements was 10.2% of the mean IVUS diameter. The repeatability of the LR system was assessed using duplicate measurements. The mean of the difference between the two measurements was nearly zero, and the repeatability coefficient was within 4.5% of the mean of the two measurements. No injury or intimal hyperplasia was found acutely or chronically after the use of the LR system. This study establishes the accuracy, reproducibility, and safety of a nonimaging 2.7-Fr catheter for lumen sizing of coronary arteries. The system provides a continuous quantitative axial profile of the mean vessel lumen in real time and may have significant utility in vascular research and clinically in the catheterization laboratory.

Prolonged dual antiplatelet therapy improves clinical outcomes in high-risk patients implanted with sirolimus-eluting stents

BACKGROUND

Although a science advisory recommending 12 months of dual antiplatelet therapy after drug-eluting stents implantation was published recently, the optimal duration of dual antiplatelet therapy has not yet been precisely determined.

HYPOTHESIS

Prolonged dual antiplatelet therapy can improve clinical outcomes in high-risk patients implanted with sirolimus-eluting stents.

METHODS

The patients implanted with sirolimus-eluting stents were assigned into standard clopidogrel therapy group (clopidogrel 75 mg/d for 12 mo) and prolonged clopidogrel therapy group (clopidogrel 75 mg/d for 18 mo). Long-term aspirin (100 mg/d) therapy was adopted in both groups. The primary endpoint was very late stent thrombosis.

RESULTS

After 12 months, 24 patients were excluded because of major adverse cardiovascular events (MACEs). Three hundred and thirty six patients surviving without MACEs were further followed up for 6 months. Between 12 and 18 months, in 160 patients with standard clopidogrel therapy, 5.6% had very late stent thrombosis. In contrast, in 176 patients with prolonged clopidogrel therapy, 1.1% had very late stent thrombosis (p<0.01, versus standard clopidogrel therapy group).

CONCLUSIONS

Prolonged dual antiplatelet therapy may be beneficial to prevent very late stent thrombosis after sirolimus-eluting stents implantation in high-risk patients.

Clopidogrel Adherence following Percutaneous Coronary Intervention with a Drug-Eluting Stent in a VA Medical Center

Background:

Antiplatelet therapy with aspirin and a thienopyridine is the standard of care for prevention of thrombosis following coronary stent implantation. Recent evidence suggests a prolonged risk of stent thrombosis; therefore, clopidogrel therapy for at least 1 year is recommended following implantation of a drug-eluting stent. Premature discontinuation of clopidogrel is a well-recognized risk factor for stent thrombosis.

Objective:

To identify the rate of adherence to clopidogrel therapy among patients who have undergone percutaneous coronary intervention (PCI).

Methods:

We queried the central Veteran Affairs (VA) pharmacy database for each patient who underwent PCI with a drug-eluting stent between September 2004 and August 2005 at a single VA medical center. Based on pharmacy refill records, patients were considered adherent to clopidogrel if they filled more than 80% of the clopidogrel prescriptions.

Results:

We observed that 20.3% of patients were nonadherent to clopidogrel therapy for the course that they were assigned. Shorter duration of therapy was the only factor that predicted increased adherence. Race, polypharmacy, marital status, prior clopidogrel use, and age did not have a significant impact on adherence. Multivariable analysis did not demonstrate any other significant relationships.

Conclusions:

In this high-risk cohort of patients who have undergone PCI, we observed a 20% incidence of nonadherence to clopidogrel therapy. Shorter duration of therapy had a significant impact on improving rates of adherence in our analysis. This observation is of particular concern given the recent recommendations to prolong antiplatelet therapy to at least 1 year following PCI with a drug-eluting stent.

Diabetes mellitus: a prothrombotic state implications for outcomes after coronary revascularization

Coronary stent thrombosis is a serious problem in the drug-eluting stent era. Despite aggressive antiplatelet therapy during and after percutaneous coronary intervention (PCI), the incidence of sub-acute stent thrombosis remains approximately 0.5%–2%, which may represent a catastrophic clinical situation. Both procedural factors and discontinuation of antiplatelet therapy are normally associated with this event. We report on simultaneous stent thromboses of two drug-eluting stents implanted in two different vessels, which resulted in a life-threatening clinical condition. Possible contributing factors that led to synergistic thrombotic effects are discussed.

Safety of drug-coated stents

BACKGROUND

Drug-coated (i.e., drug-eluting) stents (DES) are frequently used nowadays in the treatment of coronary artery disease given their superior antirestenotic effect and clear benefits in terms of reduction of repeat revascularizations and major adverse cardiac events. However, a number of safety concerns have been raised on DES.

OBJECTIVE

To appraise current data on the safety of DES.

METHODS

A thorough PubMed search was done for pertinent clinical reports on DES safety with the following string (updated December 2007): (drug(*) OR sirolimus OR paclitaxel) AND eluting(*) AND stent(*) AND (safety OR complication(*) OR thrombos(*) OR infarction) NOT (editorial[pt] OR review[pt]).

RESULTS/CONCLUSION

A total of 1077 citations were retrieved and appraised. The most relevant threats to DES safety were bleeding, difficulties in balloon deflation and retrieval, endothelial dysfunction and vasospasm, hypersensitivity, infection, late acquired malapposition and aneurysm formation, late restenosis, peri-procedural myocardial infarction, plaque prolapse, stent dislodgement or embolization, stent fracture, and stent thrombosis (with ensuing risk of death, myocardial infarction or arrhythmia). Of these, the most important and debated safety issue is the potentially increased risk in late stent thrombosis, which might offset the antirestenotic benefits of DES especially in patients at higher risk of thrombosis or who cannot comply with the recommended dual antiplatelet regimen. Nonetheless, further clinical studies are warranted to clarify whether these safety threats should be a concern for the large target population of patients with coronary artery disease most likely to benefit from DES implantation.

Generic nitric oxide (NO) generating surface by immobilizing organoselenium species via layer-by-layer assembly

A universal nitric oxide (NO) generating surface is assembled via Layer-by-Layer (LbL) deposition of sodium alginate (Alg) and organoselenium modified polyethyleneimine (SePEI) on quartz and polymeric substrates. The immobilized SePEI species is capable of catalytically decomposing S-nitrosothiol species (RSNO) to NO in the presence of thiol reducing agents (e.g., glutathione, cysteine, etc.). The stepwise buildup of the multilayer films is monitored by UV-vis spectroscopy, SEM and surface contact angle measurements. X-ray photoelectron spectroscopy is used to study the stoichiometry between the polyanion and polycation, and also the presence of Se in the catalytic LbL film. A reductive annealing process is necessary to improve the stability of freshly coated multilayer films via chain rearrangement. Chemiluminescence measurements illustrate the ability of the LbL films to generate NO from S-nitrosoglutathione (GSNO) in the presence of glutathione (GSH). Enhanced NO fluxes can be achieved by increasing the number of catalytic (SePEI/Alg) bilayers coated on the substrates. Nitric oxide generation is observed even after prolonged contact with sheep whole blood. Preliminary applications of this LbL on silicone rubber tubings and polyurethane catheters reveal similar NO generation behavior from these biomedical grade polymeric substrates.

Incidence of coronary stent thrombosis based on academic research consortium definitions

Stent thrombosis occurs infrequently after drug-eluting stent (DES) placement, but concerns have surfaced that identification of stent thrombosis based solely on angiography may underestimate the true incidence of this complication. The purpose of this study was to compare rates of stent thrombosis using Academic Research Consortium (ARC) definitions. From April 2002 to February 2005, bare-metal stents (BMSs) and DESs were placed at Wake Forest University Baptist Medical Center. Rates of ARC definite, probable, and possible stent thrombosis were evaluated. Overall, definite stent thrombosis occurred in 1.4% of BMSs and 1.1% of DESs (p = 0.47); probable stent thrombosis, in 1.0% of BMSs and 0.9% of DESs (p = 0.81); definite plus probable stent thrombosis, in 2.3% of BMSs and 1.9% of DESs (p = 0.48); and possible stent thrombosis, in 6.8% of BMSs and 3.5% of DESs (p <0.001). Rates of definite late (31 days to 1 year) and very late (>1 year) stent thrombosis were 0.9% for BMSs and 0.06% for DESs (p <0.001) and 0.16% for BMSs and 0.56% for DESs, respectively (p = 0.13). Rates of definite plus probable and late and very late stent thrombosis were 1.1% for BMSs and 0.19% for DESs (p <0.001) and 0.40% for BMSs and 0.68% for DESs, respectively (p = 0.31). Rates of possible stent thrombosis increased significantly for each thrombosis interval. In conclusion, rates of stent thrombosis using the proposed ARC definition differed by stent type, definition of stent thrombosis, and thrombosis interval. Use of the ARC probable stent thrombosis paralleled rates of definite stent thrombosis alone, but partially masked the occurrence of late (>1 year) stent thrombosis in DESs compared with BMSs.

Antiplatelet therapy in the era of drug-eluting stents: current and future perspectives

The use of drug-eluting stents (DESs) dramatically reduced in-stent restenosis. However, the increasing use of these stents has raised concern about their potential thrombogenicity. Indeed, the particularity of DES thrombosis compared with bare metal stent thrombosis is a high rate of late thrombosis. Antiplatelet therapy is efficient in preventing DES thrombosis. However, this therapy could be optimized and may be improved in the future. This article will review the mechanisms and the epidemiology of stent thrombosis. Then, we will summarize the antiplatelet therapeutic strategies used to prevent stent thrombosis and especially DES-associated thrombosis. Finally, we will present some data with regard to potential advantages and pitfalls in DES thrombosis prevention using novel antiplatelet agents currently under development, as well as future stent designs with improved healing properties.

Antiplatelet therapy for postdischarge medical management of acute coronary syndrome

Postdischarge management of patients with acute coronary syndrome is often suboptimal, despite their high risk of a subsequent event. Updated American College of Cardiology/American Heart Association guidelines emphasize the need for aggressive modification of risk factors and treatment with antiplatelet, antihypertensive, and lipid-lowering agents commenced in-hospital and continued long-term. Antiplatelet therapy involving aspirin and clopidogrel is the mainstay of secondary risk reduction. Increased adherence to medication and risk factor modification at discharge has been demonstrated with acute care quality improvement initiatives. Extension of these initiatives to postdischarge care will provide data on medication adherence post acute coronary syndrome and functional outcomes in the community setting. Successful secondary prevention of cardiovascular events requires implementation of evidence-based guidelines by physicians, and adherence to pharmacotherapy and lifestyle modifications by patients. Primary care physicians are well placed to influence adherence through their ongoing relationships with patients and can save lives by implementing secondary risk reduction measures after discharge.

Antiplatelet therapy in patients undergoing coronary stent implantation: Italian Society of Interventional Cardiology consensus document

The Italian Society of Interventional Cardiology is aware of the existence of significant local and individual disparities and discordant prescriptions in antiplatelet therapy administered with coronary stents, a critical issue due to the large use of drug-eluting stents (DES), the increasing complexity of percutaneous coronary interventions and the more stringent requirement to avoid stent thrombosis. Current percutaneous coronary intervention is attempting more aggressively to treat difficult lesions and patient cohorts with a high procedural success rate. Double antiplatelet therapy with aspirin (ASA) and thienopyridine is the best current treatment to reduce the risk of coronary stent thrombosis. Due to the lower incidence of side-effects compared to ticlopidine, clopidogrel should be the thienopyridine of choice in association with ASA in the double antiplatelet regimen. However, the combination of delayed healing with DES and the increasing complexity of the stent implantation raises more demanding safety concerns about the dosage and duration of dual antiplatelet therapy.