Is bare-metal stenting superior to balloon angioplasty for small vessel coronary artery disease? Evidence from a meta-analysis of randomized trials

Delivery of large biopharmaceuticals from cardiovascular stents: a review

This review focuses on new and emerging large-molecule bioactive agents delivered from stent surfaces in drug-eluting stents (DESs) to inhibit vascular restenosis in the context of interventional cardiology. New therapeutic agents representing proteins, nucleic acids (small interfering RNAs and large DNA plasmids), viral delivery vectors, and even engineered cell therapies require specific delivery designs distinct from traditional smaller-molecule approaches on DESs. While small molecules are currently the clinical standard for coronary stenting, extension of the DESs to other lesion types, peripheral vasculature, and nonvasculature therapies will seek to deliver an increasingly sophisticated armada of drug types. This review describes many of the larger-molecule and biopharmaceutical approaches reported recently for stent-based delivery with the challenges associated with formulating and delivering these drug classes compared to the current small-molecule drugs. It also includes perspectives on possible future applications that may improve safety and efficacy and facilitate diversification of the DESs to other clinical applications.

Impact of Vessel Size on Outcome After Implantation of Sirolimus-Eluting and Paclitaxel-Eluting Stents

OBJECTIVES

We assessed the impact of vessel size on angiographic and long-term clinical outcome after percutaneous coronary intervention (PCI) with sirolimus-eluting stents (SES) and paclitaxel-eluting stents (PES) within a randomized trial (SIRTAX [Sirolimus-Eluting Stent Compared With Paclitaxel-Eluting Stent for Coronary Revascularization]).

BACKGROUND

Percutaneous coronary intervention in small-vessel disease is associated with an increased risk of major adverse cardiac events (MACE).

METHODS

A total of 1,012 patients were randomly assigned to treatment with SES (n = 503) or PES (n = 509). A stratified analysis of angiographic and clinical outcome was performed up to 2 years after PCI according to size of the treated vessel (reference vessel diameter < or =2.75 vs. >2.75 mm).

RESULTS

Of 1,012 patients, 370 patients (37%) with 495 lesions underwent stent implantation in small vessels only, 504 patients (50%) with 613 lesions in large vessels only, and 138 patients (14%) with 301 lesions in both small and large vessels (mixed). In patients with small-vessel stents, SES reduced MACE by 55% (10.4% vs. 21.4%; p = 0.004), mainly driven by a 69% reduction of target lesion revascularization (TLR) (6.0% vs. 17.7%; p = 0.001) compared with PES at 2 years. In patients with large- and mixed-vessel stents, rates of MACE (large: 10.4% vs. 13.1%; p = 0.33; mixed: 16.7% vs. 18.0%; p = 0.83) and TLR (large: 6.9% vs. 8.6%; p = 0.47; mixed: 16.7% vs. 15.4%; p = 0.86) were similar for SES and PES. There were no significant differences with respect to death and myocardial infarction between the 3 groups.

CONCLUSIONS

Compared with PES, SES more effectively reduced MACE and TLR in small-vessel disease. Differences between SES and PES appear less pronounced in patients with large- and mixed-vessel disease. (The SIRTAX trial; http://clinicaltrials.gov/ct/show/NCT00297661?order=1; NCT00297661).

Perioperative antiplatelet therapy: the case for continuing therapy in patients at risk of myocardial infarction

Recent clinical data show that the risk of coronary thrombosis after antiplatelet drugs withdrawal is much higher than that of surgical bleeding if they are continued. In secondary prevention, aspirin is a lifelong therapy and should never be stopped. Clopidogrel is regarded as mandatory until the coronary stents are fully endothelialized, which takes 3 months for bare metal stents, but up to 1 yr for drug-eluting stents. Therefore, interruption of antiplatelet therapy 10 days before surgery should be revised. After reviewing the data on the use of antiplatelet drugs in cardiology and in surgery, we propose an algorithm for the management of patients, based on the risk of myocardial ischaemia and death compared with that of bleeding, for different types of surgery. Even if large prospective studies with a high degree of evidence are still lacking on different antiplatelet regimens during non-cardiac surgery, we propose that, apart from low coronary risk situations, patients on antiplatelet drugs should continue their treatment throughout surgery, except when bleeding might occur in a closed space. A therapeutic bridge with shorter-acting antiplatelet drugs may be considered.

Small coronary arteries treated with sirolimus-eluting stents: one-year results of the PORTO multicentre registry

AIMS

To assess the effectiveness and safety of sirolimus-eluting stents (SES) in de novo native coronary lesions in small vessels (</= 2.5 mm).

METHODS AND RESULTS

PORTO was a multicentre, prospective registry, performed in 274 patients. Of these, 120 (43.8%) patients were diabetic. A total of 324 lesions were treated with 347 SES. The primary end-point was 6-month in-stent late luminal loss (LL); secondary end-points included in-stent and in-segment binary restenosis (BR), target lesion revascularisation (TLR), target vessel revascularisation (TVR) and major adverse cardiac events (MACE) rate at six months and one-year. Pre-specified subgroup analysis included the comparison between diabetic and non-diabetic patients, and patients with stents of different diameter (2.25 mm vs. 2.5 mm) and length (</= 18 mm vs. >/= 23 mm).The mean (SD) reference vessel diameter of the treated segment was 2.08 (0.33) mm and lesion length 11.04 (6.0) mm. After six months, LL was 0.07 (0.37) mm. BR was 5.1% in-stent and 9.1% in-segment. At one year, TLR was 5.6% and TVR was 9.0%. MACE rate was 2.6% at six months and 8.6% at one year with 2.3% cardiac death and 1.5% non-fatal myocardial infarction. Stent thrombosis rate at one year was 0.8% per protocol. There were more MACE in diabetic patients (12.8%) than in non-diabetic (5.4%, p=0.046), but no other significant differences in clinical and angiographic parameters were noted between the subgroups analysed.

CONCLUSIONS

The use of SES for lesions in very small coronary arteries proved to be safe and efficacious, irrespective of the size and length of the stents, with low restenosis and repeat revascularisation rates at one year.

Perioperative use of anti-platelet drugs

Performing a surgical procedure on a patient undergoing anti-platelet therapy raises a dilemma: is it safer to withdraw the drugs and reduce the haemorrhagic risk, or to maintain them and reduce the risk of myocardial ischaemic events? Based on recent clinical data, this review concludes that the risk of coronary thrombosis on anti-platelet drugs withdrawal is much higher than the risk of surgical bleeding when maintaining them. In secondary prevention, aspirin is a lifelong therapy and should never be stopped. Clopidogrel is mandatory as long as the coronary stents are not fully endothelialized, which takes 6-24 weeks depending on the technique used, but might be required for a longer period.

Anatomical and physiologic assessments in patients with small coronary artery disease: final results of the Physiologic and Anatomical Evaluation Prior to and After Stent Implantation in Small Coronary Vessels (PHANTOM) trial

BACKGROUND

Patients with small coronary arteries are at high risk for complications after percutaneous coronary intervention (PCI). The objective of our study was to investigate the correlation between angiography, intravascular ultrasound (IVUS), and fractional flow reserve (FFR) in patients with moderate stenoses in small (<2.8 mm) coronary arteries.

METHODS AND RESULTS

Sixty consecutive patients, of 800 scheduled for PCI during the study period, were prospectively enrolled in the study. The FFR was measured after a 2-minute infusion of adenosine. For the preprocedural assessments, 60 patients underwent an FFR measurement, 56 underwent an IVUS, and 60 underwent an angiography; for the postprocedural assessments, 22 patients underwent an FFR measurement, 18 underwent an IVUS, and 22 underwent an angiography. The jeopardy score for the target vessel was calculated. Data were analyzed by an independent core laboratory. Patients with an FFR >0.75 were deferred from PCI. Patients were stratified in 2 groups according to their FFR values (< or =0.75 vs >0.75) and were followed for 1 year. Significant (FFR < or =0.75) coronary stenosis was observed in only 35% of the patients. The mean preprocedural FFR values were 0.79 +/- 0.13 for the overall population, 0.64 +/- 0.08 for the patients with an FFR < or =0.75, and 0.87 +/- 0.06 for the patients with an FFR >0.75. There was no correlation between angiography, IVUS, and FFR. The jeopardy score was inversely correlated with FFR (R = -0.32). Only a third of the patients with optimal stenting defined by IVUS achieved an FFR >0.90. After 1 year, 24% of the patients with an FFR < or =0.75 required a repeat PCI. There was no occurrence of myocardial infarction or death, and only 2.6% of the patients deferred from PCI required revascularization.

CONCLUSION

Anatomical parameters are limited in determining the hemodynamic significance of small coronary disease. Most moderate stenoses in small coronaries could be safely deferred from PCI based on FFR.

Usefulness of routine unfractionated heparin infusion following primary percutaneous coronary intervention for acute myocardial infarction in patients not receiving glycoprotein IIb/IIIa inhibitors

We evaluated the utility of a routine postprocedure course of unfractionated heparin after primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) in patients not receiving glycoprotein IIb/IIIa inhibitors. In the CADILLAC study, 2,082 patients with AMI who underwent primary PCI were randomized to receive stents versus percutaneous transluminal coronary angioplasty (PTCA), each with or without abciximab. In a subset of 976 patients who did not receive abciximab, we compared outcomes of patients who received postprocedural heparin (n = 758; 78%; median duration 2 days) with those who did not. In 421 patients treated with PTCA, postprocedural heparin use was associated with lower in-hospital major adverse cardiac events (MACEs; 5.3% vs 11.4%, p = 0.069), 1-year MACEs (22% vs 31%, p = 0.08), and decreased in-hospital moderate/severe bleeding (2.3% vs 8.9%, p = 0.01). By multivariate analyses, heparin use correlated with freedom from in-hospital and 1-year MACEs in patients after PTCA. In contrast, in 555 patients who underwent stenting, postprocedural heparin use was associated with increased bleeding and hospitalization costs without a decrease in early or late MACEs. In conclusion, in patients with AMI treated with coronary stenting without glycoprotein IIb/IIIa inhibitors, routine postprocedural heparin was not associated with any significant benefits and may be safely omitted. However, in a subset of patients treated with PTCA, postprocedural heparin use was independently associated with fewer in-hospital and 1-year MACEs.

Drug-eluting stents for the treatment of bifurcation lesions: a randomized comparison between paclitaxel and sirolimus stents

BACKGROUND

Drug-eluting stents have been shown to reduce restenosis in many types of lesions. The purpose of this article is to assess the efficacy of sirolimus- and paclitaxel-eluting stents in patients with bifurcation lesions.

METHODS

Between June 2003 and October 2004, 205 patients were enrolled in a prospective randomized trial; 103 patients were assigned to sirolimus stents and 102 patients to paclitaxel stents. All patients were treated by provisional T-stenting.

RESULTS

There were no differences between groups in terms of age, risk factors, clinical condition, location of the bifurcation lesion, or other technical factors. Angiographic data and immediate results were also similar in both groups. Three patients developed inhospital non-Q-wave acute myocardial infarction (2 from the sirolimus group and 1 from the paclitaxel group). Follow-up angiography was obtained in 109 patients (53%). In the sirolimus group, 5 patients developed restenosis (9%): 1 at the main vessel, 2 at the side branch, and 2 in both branches. In contrast, 16 patients from the paclitaxel group had restenosis (29%): 6 at the main vessel, 5 at the side branch, and 5 in both branches. Target lesion revascularization at 24 +/- 5 months post stenting occurred in 4 patients from the sirolimus group (4%) and in 13 from the paclitaxel group (13%) (P < .05). Late loss at the main vessel in the sirolimus group patients was 0.31 +/- 0.59 versus 0.60 +/- 0.77 mm in patients from the paclitaxel group (P < .05).

CONCLUSIONS

Patients with bifurcation lesions treated by sirolimus showed significantly lower rates of late loss, restenosis and target lesion revascularization than patients treated with paclitaxel-eluting stents.

Factors predictive of cardiac events and restenosis after sirolimus-eluting stent implantation in small coronary arteries

OBJECTIVES

Predictors of cardiac events and restenosis after sirolimus-eluting stent (SES) implantation in small coronary arteries were evaluated.

BACKGROUND

Although SES implantation has markedly reduced the risk of restenosis, small vessel disease remains a major cause of SES failure.

METHODS

We prospectively investigated the factors predictive of cardiac events and restenosis in 1,092 consecutive patients who received SES implantation for 1,269 lesions in small coronary arteries (< or = 2.8 mm). Follow-up angiography at 6 months was performed in 751 patients with 889 lesions (follow-up rate 70.3%).

RESULTS

Restenosis (diameter stenosis > or = 50%) was angiographically documented in 65 patients with 77 lesions (8.7%): 55 focal (71.4%), 8 diffuse (10.4%), 2 diffuse proliferative (2.6%), and 12 total (15.6%). Lesion length, stent length, reference artery size, and in-stent restenotic lesions were univariate predictors of restenosis. By multivariate analysis, lesion length (OR 1.04; 95% CI 1.02-1.05; P < 0.001) and in-stent restenotic lesions (OR 3.38; 95% CI 1.80-6.35; P < 0.001) were significant independent predictors of restenosis. During follow-up (23.2 +/- 7.9 months), there were 17 deaths (5 cardiac and 12 noncardiac), 5 nonfatal Q-wave myocardial infarctions, and 42 target lesion revascularizations. The cumulative probability of survival without major adverse cardiac events (MACE) was (96.6 +/- 0.6)% at 1 year and (95.1 +/- 0.7)% at 2 years. In multivariate analysis, lesion length (HR 1.04; 95% CI 1.01-1.07; P = 0.004) and in-stent restenotic lesions (HR 3.29; 95% CI 1.58-6.86; P = 0.001) were independently related to MACE.

CONCLUSIONS

SES implantation in small coronary arteries is safe and effective, with lesion length having a major impact on restenosis and MACE.

Comparison between stenting and balloon angioplasty in patients undergoing primary angioplasty of small coronary vessels

BACKGROUND

Primary angioplasty has been shown to improve outcomes in selected patients with ST-segment elevation myocardial infarction. However, no information has been reported so far in small vessels. In the Zwolle-6 randomized trial, consecutive patients with ST-segment elevation myocardial infarction were randomized to stenting or to balloon angioplasty without any exclusion criterion. In this study, we present data on patients with small vessels (< 3.0 mm).

METHODS

From April 1997 to October 2001, 798 patients randomized to balloon angioplasty or to stenting before their initial angiogram underwent primary angioplasty of small vessels, defined according to a postprocedural reference diameter < or = 3 mm. One-year follow-up data were available from all patients.

RESULTS

Three hundred eighty-seven patients were randomized to stent, whereas 411 were to balloon. The crossover rates from balloon to stent and from stent to balloon were 28% and 13.9%, respectively (P < .001). The groups were comparable in terms of postprocedural TIMI flow, myocardial blush grade, distal embolization, and ST-segment resolution. No difference was observed in 1-year mortality (7.2% vs 5.8%, P = not significant [NS]), target vessel revascularization (17.8% vs 22.1%, P = NS), and major adverse cardiac events (24.8% vs 29.0%, P = NS) between the groups.

CONCLUSIONS

As compared with balloon angioplasty, routine stenting does not seem to improve clinical outcomes in patients undergoing primary angioplasty of small vessels. Future trials are certainly needed to evaluate the safety and benefits of drug-eluting stents in this high-risk subset of patients.

Vessel Size and Outcome After Coronary Drug-Eluting Stent Placement

OBJECTIVES

This study sought to investigate the influence of vessel size on the outcomes of patients after drug-eluting stent (DES) implantation.

BACKGROUND

There are no dedicated studies on the influence of vessel size on the outcomes of patients treated with different DES.

METHODS

The study population was composed of 2,058 consecutive patients who received sirolimus-eluting stents (SES) or paclitaxel-eluting stents (PES). Patients were grouped into tertiles according to vessel size (<2.41 mm in the lower tertile, 2.41 to 2.84 mm in the middle tertile, and >2.84 mm in the upper tertile). The primary end point was target lesion revascularization (TLR). Secondary end points were binary angiographic restenosis and the composite of death or myocardial infarction.

RESULTS

Vessel size did not influence the composite end point of death and myocardial infarction. The TLR rates were higher among patients in the lower tertile (12.1%) as compared with the middle (8.4%) and upper (8.0%) tertiles (p = 0.02). In a multivariate analysis, vessel size emerged an independent predictor of TLR (p = 0.009). The model showed also a significant interaction between DES type and vessel size regarding TLR (p = 0.008). There was a significant difference in TLR rates among patients treated with SESs (8.6%) and PESs (16.4%) in the lower tertile (p = 0.002), but not in the middle and upper tertiles.

CONCLUSIONS

The influence of vessel size on restenosis is related to the specific DES used, with SESs providing better outcomes than PESs in small but not in large coronary vessels.

Angioplasty for renovascular hypertension in children: 20-year experience

OBJECTIVE

Our aim was to evaluate the clinical outcomes, safety, and efficacy of percutaneous transluminal angioplasty for renovascular hypertension in children.

METHODS

A retrospective review of data for all children with renovascular hypertension who underwent percutaneous transluminal angioplasty at a single center between 1984 and 2003 was performed. Patients with renal transplants and inflammatory multisystem diseases were excluded.

RESULTS

Thirty-three children, 1.9 to 17.9 years of age (median: 10.3 years), underwent renal angioplasty and/or stenting. Underlying syndromes were present in 10. On angiograms, 16 had bilateral renal artery stenosis, 15 intrarenal disease, 8 aortic stenosis, and 7 cerebrovascular disease. Forty-eight percutaneous transluminal angioplasty procedures were performed, including 15 stenting procedures. There was a high rate of restenosis after stenting (7 of 19 cases, compared with 2 of 27 cases after balloon dilation). Outcomes were cured (ie, blood pressure normal without treatment) for 9 patients, improved blood pressure with same or reduced treatment for 7, blood pressure maintained in >95th percentile because of cerebrovascular disease for 2, no change in blood pressure despite technical success for 10, and technical failure for 5. Blood pressure control improved in 11 of 13 children who had main renal artery disease alone and in 6 of 20 with associated intrarenal disease or stenoses in other vascular beds. There was 1 procedure-related death and 5 minor complications.

CONCLUSIONS

Angioplasty produced clinically worthwhile improvement for approximately 50% of patients. High incidence rates of extrarenal involvement and intrarenal disease and a high restenosis rate after stenting accounted for poor blood pressure control in the rest.

Clinical effectiveness of bare-metal stenting compared with balloon angioplasty in total coronary occlusions: insights from a systematic overview of randomized trials in light of the drug-eluting stent era

BACKGROUND

We sought to compare, using meta-analytic techniques, bare-metal stent versus balloon angioplasty in the percutaneous treatment of total coronary occlusions by means of a quantitative systematic review and to indicate new avenues for future treatments.

METHODS

MEDLINE and CENTRAL were searched. Inclusion criteria were random allocation, prospective comparison, and intention to treat. Random-effect odds ratios (ORs) with 95% confidence intervals (CIs) for death, myocardial infarction (MI), repeated revascularization, major adverse cardiac events (MACE), and angiographic restenosis and reocclusion were computed.

RESULTS

Nine trials (1409 patients) were included. Death rate was not different in the 2 groups, 0.4% after stenting versus 0.7% after balloon angioplasty (OR 0.72, 95% CI 0.21-2.50). MI rate was significantly increased after stenting (6.7% vs 3.4%, OR 2.06, 95% CI 1.22-3.46), mainly because of a higher rate of periprocedural non-Q-wave MI. By contrast, the risk of repeated revascularization was significantly reduced by stenting (17% vs 32%, OR 0.41, 95% CI 0.31-0.53). This yielded to an overall reduction in the rate of MACE after stenting (23.2% vs 35.4%, OR 0.49, 95% CI 0.36-0.68). Angiographic restenosis and reocclusion were also decreased by stent (41.1% vs 60.9%, OR 0.36, 95% CI 0.23-0.57; 6.8% vs 16%, OR 0.36, 95% CI 0.22-0.59, respectively).

CONCLUSIONS

In total coronary occlusions, stenting yields an important benefit over balloon angioplasty in reduction of MACE, repeated revascularizations, and angiographic restenosis and reocclusion. However, these events remain frequent. Moreover, the finding of an increased rate of periprocedural minor myocardial damage after stenting casts caution. New strategies aimed to reduce the need of repeated revascularizations and periprocedural MIs should be further investigated.

Compliance with QUOROM and quality of reporting of overlapping meta-analyses on the role of acetylcysteine in the prevention of contrast associated nephropathy: case study

OBJECTIVE

To appraise multiple systematic reviews on the same clinical topic, focusing on predictors and correlates of quality of reporting of meta-analysis (QUOROM) scores.

DESIGN

Case study.

SETTING

Reviews providing at least individual quantitative estimates on role of acetylcysteine in the prevention of contrast associated nephropathy.

DATA SOURCES

PubMed, the database of abstracts of reviews of effects, and the Cochrane database of systematic reviews (updated March 2005).

MAIN OUTCOME MEASURES

Funding, compliance with the QUOROM checklist, scores on the Oxman and Guyatt quality index, and authors' recommendations.

RESULTS

10 systematic reviews, published August 2003 to March 2005, were included. Nine pooled events despite heterogeneity and five recommended routine use of acetylcysteine, whereas the remaining studies called for further research. Compliance with the 18 items on the QUOROM checklist was relatively high (median 16, range 11 to 17), although shorter manuscripts had significantly lower scores (R = 0.73; P = 0.016). Reviewers who reported previous not for profit funding were more likely to score higher on the Oxman and Guyatt quality index. No association was found between QUOROM and Oxman and Guyatt scores (R = -0.06; P = 0.86), mainly because of greater emphasis of the Oxman and Guyatt scores on the appraisal of bias in selection and validity assessment (inadequate in five reviews).

CONCLUSIONS

Multiple systematic reviews on the same clinical topic varied in quality of reporting and recommendations. Longer manuscripts and previous not for profit funding were associated with higher quality.

Two-year clinical outcome after coronary stenting of small vessels using 2.25-mm sirolimus- and paclitaxel-eluting stents: Insight into the RESEARCH and T-SEARCH registries

OBJECTIVES

To evaluate long-term outcomes after drug-eluting stents (DES) implantation in small coronary vessels.

BACKGROUND

Sirolimus-eluting stents (SES) and paclitaxel-eluting stents (PES) have been reported to improve both the angiographic and clinical outcomes compared with bare metal stents even in 'real world' settings. Currently, no data is available on long-term outcomes after DES implantation in small vessels.

METHODS

Since April 2002, our institution has implanted DES, either SES or PES, as a default strategy in all patients irrespective of their clinical presentation. Between October 2002 and September 2003, 197 consecutive patients were enrolled: 107 consecutive patients received at least one 2.25-mm SES (SES group) and 90 consecutive patients received at least one 2.25-mm PES (PES group).

RESULTS

The two cohorts presented with high-risk characteristics. At 2 years, the cumulative incidence of major adverse cardiac events (MACE) in the SES group was significantly lower than that in the PES group (10.3% vs. 23.3%, P=0.02). There were two subacute angiographic stent thromboses in the PES group and none in the SES group. By multivariate analysis, PES utilization (HR 2.37, 95% CI 1.07-5.26), presentation with acute coronary syndromes (ACS) (HR 3.34, 95% CI 1.44-7.70) and multi-vessel disease (MVD) (HR 3.91, 95% CI 1.27-12.0) were identified as independent predictors of MACE.

CONCLUSIONS

In an unselected population treated for small vessel disease, SES were associated with significantly better 2-year clinical outcomes than PES. The use of PES and the presentation with ACS and MVD were identified as independent predictors of MACE.