Randomized Comparison of Strut Coverage between Ticagrelor and Clopidogrel in Acute Myocardial Infarction at 3-Month Optical Coherence Tomography

Stent expansion evaluated by optical coherence tomography and subsequent outcomes

Regarding stent expansion indices, previous optical coherence tomography (OCT) studies have shown minimal stent area (MSA) to be most predictive of adverse events. We sought to evaluate the impact of various stent expansion and apposition indices by post-stent OCT on clinical outcomes and find OCT-defined optimal stent implantation criteria. A total of 1071 patients with 1123 native coronary artery lesions treated with new-generation drug-eluting stents with OCT guidance and final post-stent OCT analysis were included. Several stent expansion indices (MSA, MSA/average reference lumen area, MSA/distal reference lumen area, mean stent expansion, and stent expansion by linear model [stent volume/adaptive reference lumen volume]) were evaluated for their association with device-oriented clinical endpoints (DoCE) including cardiac death, target vessel-related myocardial infarction (MI) or stent thrombosis, and target lesion revascularization. MSA was negatively correlated with the risk of DoCE (hazard ratio [HR] 0.80 [0.68‒0.94]). However, stent expansion by linear model representing the overall volumetric stent expansion was associated with greater risk of DoCE (HR 1.02 [1.00‒1.04]). As categorical criteria, MSA < 5.0 mm² (HR 3.90 [1.99‒7.65]), MSA/distal reference lumen area < 90% (HR 2.16 [1.12‒4.19]), and stent expansion by linear model ≥ 65.0% (HR 1.95 [1.03‒3.89]) were independently associated with DoCE. This OCT study highlights the importance of sufficient stent expansion to achieve adequate, absolute, and relative MSA criteria for improving clinical outcome. It also emphasises that overall volumetric excessive stent expansion may have detrimental effects.

Efficacy and Safety of Clopidogrel Versus Ticagrelor as Part of Dual Antiplatelet Therapy in Acute Coronary Syndrome-A Systematic Review and Meta-analysis

ABSTRACT

The efficacy and safety of clopidogrel compared with ticagrelor as part of dual antiplatelet therapy in patients, and in older patients, with acute coronary syndrome is reviewed. PubMed, Embase, the Cochrane Library, MEDLINE, and HTA databases were searched (September 2, 2020) for randomized controlled trials (RCTs). Pooled risk differences (clopidogrel minus ticagrelor) were estimated using random-effects meta-analyses, and certainty of evidence was assessed according to Grading of Recommendations Assessment, Development, and Evaluation. In all, 29 RCTs were identified. The risk difference for all-cause mortality was 0.6% (-0.03% to 1.3%), cardiovascular (CV) mortality: 0.6% (95% confidence interval: 0.01% to 1.1%), myocardial infarction (MI): 0.9% (0.4% to 1.3%), stent thrombosis: 0.7% (0.4 to 1.1%), clinically significant bleeding: -1.9% (-3.7% to -0.2%), major bleeding: -0.9% (-1.6% to -0.1%), and dyspnea: -5.8% (-7.7% to -3.8%). In older patients, there were no differences between the comparison groups regarding all-cause mortality, CV mortality, and MI, whereas the risk of clinically significant bleeding and major bleeding was lower in the clopidogrel group, -5.9% (-11 to -0.9%, 1 RCT) and -2.4% (-4.4% to -0.3%), respectively. Compared with ticagrelor, clopidogrel may result in little or no difference regarding all-cause mortality. Although not evident in older patients, it cannot be excluded that clopidogrel may be slightly less efficient in reducing the risk of CV mortality and MI, whereas ticagrelor is probably more efficacious in reducing the risk of stent thrombosis. Clopidogrel results in a reduced risk of dyspnea and clinically significant bleeding and in older people probably in a reduced risk of major bleeding.

Can an ultrathin strut stent design and a polymer free, proendothelializing probucol matrix coating improve early strut healing? The FRIENDLY-OCT trial. An intra-patient randomized study with OCT, evaluating early strut coverage of a novel probucol coated polymer-free and ultra-thin strut sirolimus-eluting stent compared to a biodegradable polymer sirolimus-eluting stent

BACKGROUND

incomplete strut coverage determines the risk of stent thrombosis in the first months after stent implantation.

AIMS

To evaluate the potential better early healing of a novel probucol coated polymer free ultra-thin strut sirolimus eluting stent (PF-SES). [Clinical trial unique identifier: NCT02785237].

METHODS

Patients with two (angiographically similar) lesions with clinical indication for PCI were enrolled. The investigated stent was compared to a thin strut, bioresorbable polymer, sirolimus eluting stent (BP-SES). Every patient received both stents, one in each lesion, assigned in a randomized sequence. OCT was systematically performed at 3 months. Primary end point was the difference in the proportion of covered struts at 3 months (defined as ≥20 μm of tissue coverage). Secondary end points included differences in percentage of uncovered struts (0 μm coverage), mean strut coverage thickness, and malapposed struts' coverage proportion. Major adverse cardiac events (cardiac death, myocardial infarction, target lesion revascularization, and definite or probable stent thrombosis) at 12 months were also evaluated.

RESULTS

70 patients were included. At 3 months, a consistent and significantly higher strut coverage rate (≥20 μm) was observed in PF-SES as compared to BP-SES, both for well apposed (87.3% versus 79.1%, p < 0.001) and malapposed struts (50.4% vs 37.8%, p 0.00). Uncoverage rate (0 μm) was also significantly lower for the PF-SES (3.1% vs 5.3%, p < 0.001). There were no differences in clinical endpoints.

CONCLUSION

The probucol coated non-polymeric ultra-thin strut sirolimus eluting stent showed a significantly better early strut coverage at 3 months.

Differential Vascular Responses to New-Generation Drug-Eluting Stenting According to Clinical Presentation: Three-Month Optical Coherence Tomographic Study

We evaluated early vascular responses after new-generation drug-eluting stent (DES) implantation. From 2 randomized trials, we identified 471 patients (138 patients with acute myocardial infarction [AMI] vs 333 patients with stable angina or unstable angina [SA/UA]) treated by DESs who underwent serial optical coherence tomography (OCT) from postprocedure to 3 months. At 3-month follow-up OCT, malapposed strut percentage was higher in AMI than in SA/UA (5.3% vs 0.7%, P < .001); it was markedly increased from postprocedure in AMI (2.0%-5.3%, P < .001), whereas it decreased in SA/UA (1.7%-0.7%, P < .001). Patients with AMI showed a higher risk of persistent (59% vs 37%; P < .001) or late-acquired malapposition (15% vs 8%; P = .04). Uncovered strut percentage at 3 months was also higher in AMI than in SA/UA (13.1% vs 6.7%, P < .001). The AMI presentation was the significant risk factor for both significant stent malapposition (SM, ≥200 μm; odds ratio [OR] = 3.45, CI = 1.85-7.14, P < .001) and uncovered stent (% uncovered struts >6.0%; OR = 2.44, CI = 1.35-4.76, P = .004), together with malapposed distance and postprocedural thrombi. Further, AMI presentation was the predictor for the occurrence of early period late-acquired and persistent malapposition. Serial OCT comparison analyses showed that patients with AMI compared with patients with SA/UA showed more delayed strut coverage, more severe degree SM or uncovered stents, and higher incidences of early period persistent or late-acquired SM.

Endpoint selection for noninferiority percutaneous coronary intervention trials: a methodological description

Background:

The objective of this review is to provide a practical update on endpoint selection for noninferiority (NI) studies in percutaneous coronary intervention studies.

Methods:

A PubMed search was conducted for predefined terms to explore the use of NI designs and intrapatient comparisons to determine their current importance. Sample size calculations for the most frequently used endpoints with NI hypotheses were done to increase statistical awareness.

Results:

Reported NI trials, with the most frequently chosen clinical endpoint of major adverse cardiac events (MACE), had NI margins ranging from 1.66% to 5.00%, resulting in patient populations of 400–1500 per treatment group. Clinical study endpoints comprising of MACE complemented with rates of bleeding complications and stent thrombosis (ST) are suggested to conduct a statistically and clinically meaningful NI trial. Study designs with surrogate endpoints amenable to intrapatient randomizations, are a very attractive option to reduce the number of necessary patients by about half. Comparative clinical endpoint studies with MACE and ST/bleeding rates to study a shortened dual antiplatelet therapy (DAPT) in coronary stent trials are feasible, whereas ST as the sole primary endpoint is not useful.

Conclusions:

Expanded composite clinical endpoints (MACE complemented by ST and bleeding rates and intrapatient randomization for selected surrogate endpoints) may be suitable tools to meet future needs in device approval, recertification and reimbursement.

Impact of late stent malapposition after drug-eluting stent implantation on long-term clinical outcomes

BACKGROUND AND AIMS

The impact of late drug-eluting stent (DES) malapposition detected by optical coherence tomography (OCT) on long-term clinical outcomes has not been clearly established. We evaluated long-term clinical outcomes of late stent malapposition (LSM) detected by OCT in a qualified study population.

METHODS

A total of 428 patients were selected from previous randomized OCT studies that evaluated the degree of strut coverage of different DESs at a 3-12-month follow-up OCT examination. These patients were assigned to one of two groups based on the presence (n = 136) or absence (n = 292) of LSM on follow-up OCT images (performed at 7.0 ± 3.4 months after DES implantation). The cumulative rates of composite events (cardiac death, target-vessel-related myocardial infarction, target-vessel revascularization, and stent thrombosis) were compared between the two groups.

RESULTS

During 73.7 ± 18.3 months of follow-up, cardiac death or (very) late stent thrombosis did not occur in either group. The cumulative rate of composite events was similar among the patients in each group (6.2% in patients with LSM vs. 11.7% in those without LSM) [hazard ratio (HR) = 0.569, 95% confidence interval (CI) = 0.257-1.257, p = 0.163]. Target vessel-related myocardial infarction occurred in 0.7% of patients with LSM vs. 1.5% of those without LSM (HR = 0.521, 95% CI = 0.058-4.670, p = 0.560). Target-vessel revascularization was performed in 5.4% of patients with LSM vs. 10.2% of those without LSM (HR = 0.574, 95% CI = 0.246-1.343, p = 0.201).

CONCLUSIONS

Cardiac death or (very) late stent thrombosis did not occur in patients with OCT-detected LSM during long-term follow-up. The presence of OCT-detected LSM was not associated with adverse clinical events.

Severe Acute Stent Malapposition After Drug-Eluting Stent Implantation: Effects on Long-Term Clinical Outcomes

Background

The effects of severe acute stent malapposition (ASM) after drug‐eluting stent implantation on long‐term clinical outcomes are not clearly understood. We evaluated long‐term clinical outcomes of severe ASM using optical coherence tomography.

Methods and Results

We pooled patient‐ and lesion‐level data from 6 randomized studies. Five studies investigated follow‐up drug‐eluting stent strut coverage and one investigated ASM. In this data set, a total of 436 patients with 444 lesions underwent postintervention optical coherence tomography examination and these data were included in the analysis. Severe ASM was defined as lesions with ≥400 μm of maximum malapposed distance or ≥1 mm of maximum malapposed length. Composite events (cardiac death, target lesion–related myocardial infarction, target lesion revascularization, and stent thrombosis) were compared between patients with and without severe ASM. The postintervention optical coherence tomography findings indicated that 62 (14.2%) patients had lesions with ≥400 μm of maximum malapposed distance and 186 (42.7%) patients had lesions with ≥1 mm of maximum malapposed length. The 5‐year clinical follow‐up was completed in 371 (86.1%) of the eligible 431 patients. The cumulative rate of composite events was similar among the patients in each group during 5‐year follow‐up: 3.3% in patients with ASM ≥400 μm of maximum malapposed distance versus 3.1% in those with no ASM or ASM <400 μm of maximum malapposed distance (P=0.89), and 1.2% in patients with ASM ≥1 mm of maximum malapposed length versus 4.6% in those with no ASM or ASM <1 mm of maximum malapposed length (P=0.06).

Conclusions

During the 5‐year follow‐up, ASM severity was not associated with long‐term clinical outcomes in patients treated with drug‐eluting stents.

Long-Term Clinical Outcomes of Late Stent Malapposition Detected by Optical Coherence Tomography After Drug-Eluting Stent Implantation

Background

The relationship between late stent malapposition (LSM) and adverse cardiovascular events is controversial. Studies are needed to evaluate long‐term (>5 years) clinical outcomes of LSM detected by optical coherence tomography (OCT) after drug‐eluting stent implantation.

Methods and Results

We investigated long‐term clinical outcomes of OCT‐detected LSM in 351 patients who received drug‐eluting stents and were examined by both poststent and follow‐up OCT (175±60 days after drug‐eluting stent implantation) from January 2009 to December 2011. LSM was observed in 99 patients (28%). We evaluated the cumulative rate of composite events (cardiovascular death, target‐vessel–related myocardial infarction, target‐vessel revascularization, and stent thrombosis). During 80.1±24.5 months of follow‐up, very late stent thrombosis did not occur in any patients with LSM. The cumulative 8‐year rate of composite events was 7.3% in patients with LSM and 10.5% in patients without LSM (P=0.822, log‐rank test). We further divided patients into the following 4 groups: patients with both late‐persistent and late‐acquired stent malapposition (n=23), patients with late‐persistent stent malapposition alone (n=45), patients with late‐acquired stent malapposition alone (n=31), and patients without LSM (n=252). The cumulative 8‐year rates of composite events were similar among these 4 groups (0%, 9.6%, 9.7%, and 10.5%, respectively; P=0.468 by log‐rank test).

Conclusions

During long‐term follow‐up (>5 years), very late stent thrombosis did not occur in patients with OCT‐detected LSM. The rates of adverse clinical events were similar between patients with LSM versus those without LSM. Presence of OCT‐detected LSM was not associated with unfavorable clinical outcomes.

See Editorial by Ali et al