Six-months clinical and intracoronary imaging follow-up after reverse T and protrusion or double-kissing and crush stenting for the treatment of complex left main bifurcation lesions

Background

There is a debate regarding the best stent strategy for unprotected distal left main (LM) bifurcation disease. Among two-stent techniques, double-kissing and crush (DKC) is favored in current guidelines but is complex and requires expertise. Reverse T and Protrusion (rTAP) was shown to be a comparable strategy regarding short-term efficacy and safety, but with reduced procedural complexity.

Aim

To compare rTAP vs. DKC by optical coherence tomography (OCT) on the intermediate term.

Methods

52 consecutive patients with complex unprotected LM stenoses (Medina 0,1,1 or 1,1,1) were randomized to either DKC or rTAP and followed-up for a median of 189[180-263] days for clinical and OCT outcomes.

Results

At follow-up OCT showed similar change in the side branch (SB) ostial area (primary endpoint). The confluence polygon showed a higher percentage of malapposed stent struts in the rTAP group that did not reach statistical significance (rTAP: 9.7[4.4-18.3] % vs. DKC: 3[0.07-10.9] %; p = 0.064). It also showed a trend towards larger neointimal area relative to the stent area (DKC: 8.8 [6.9 to 13.4] % vs. rTAP: 6.5 [3.9 to 8.9] %; p = 0.07), and smaller luminal area (DKC: 9.54[8.09-11.07] mm² vs. rTAP: 11.21[9.53-12.42] mm²; p = 0.09) in the DKC group. The minimum luminal area in the parent vessel distal to the bifurcation was significantly smaller in the DKC group (DKC: 4.64 [3.64 to 5.34] mm² vs. rTAP: 6.76 [5.20 to 7.29] mm²; p = 0.03). This segment also showed a trend for smaller stent areas (p = 0.05 to 0.09), and a bigger neointimal area relative to the stent area (DKC: 8.94 [5.43 to 10.5]% vs. rTAP: 4.75 [0.08 to 8.5]%; p = 0.06) in the DKC patients. The incidence of clinical events was comparably low in both groups.

Conclusion

At 6-months, OCT showed a similar change in the SB ostial area (primary endpoint) in rTAP compared to DKC. There was also a trend for smaller luminal areas in the confluence polygon and the distal parent vessel, and a larger neointimal area relative to the stent area, in DKC, along with a tendency for more malapposed stent struts in rTAP.

Clinical Trial Registration

https://clinicaltrials.gov/ct2/show/NCT03714750, identifier: NCT03714750.

Intravascular imaging in coronary stent restenosis: Prevention, characterization, and management

Despite the introduction of drug-eluting stents to combat the neointimal hyperplasia that occurred after BMS implantation, in-stent restenosis is still encountered in a significant number of patients, particularly as increasingly complex lesions are tackled by percutaneous coronary intervention. Many biological and mechanical factors interplay to produce restenosis, some of which are avoidable. Intravascular imaging provided unique insights into various forms of stent-related mechanical issues that contribute to this phenomenon. From a practical perspective, intravascular imaging can therefore help to optimize the stenting procedure to avert these issues. Moreover, once the problem of restenosis eventuates, imaging can guide the management by tackling the underlying identified mechanism. Finally, it can be used to evaluate the re-intervention results. Nevertheless, with the emergence of different treatment options, more evidence is needed to define patient/lesion-specific characteristics that may help to tailor treatment selection in a way that improves clinical outcomes.

Optical Coherence Tomography: An Eye Into the Coronary Artery

Optical coherence tomography (OCT) is slowly but surely gaining a foothold in the hands of interventional cardiologists. Intraluminal and transmural contents of the coronary arteries are no longer elusive to the cardiologist's probing eye. Although the graduation of an interventionalist in imaging techniques right from naked eye angiographies to ultrasound-based coronary sonographies to the modern light-based OCT has been slow, with the increasing regularity of complex coronary cases in practice, such a transition is inevitable. Although intravascular ultrasound (IVUS) due to its robust clinical data has been the preferred imaging modality in recent years, OCT provides a distinct upgrade over it in many imaging and procedural aspects. Better image resolution, accurate estimation of the calcified lesion, and better evaluation of acute and chronic stent failure are the distinct advantages of OCT over IVUS. Despite the obvious imaging advantages of OCT, its clinical impact remains subdued. However, upcoming newer trials and data have been encouraging for expanding the use of OCT to wider indications in clinical utility. During percutaneous coronary intervention (PCI), OCT provides the detailed information (dissection, tissue prolapse, thrombi, and incomplete stent apposition) required for optimal stent deployment, which is the key to successfully reducing the major adverse cardiovascular event (MACE) and stent-related morbidities. The increasing use of OCT in complex bifurcation stenting involving the left main (LM) is being studied. Also, the traditional pitfalls of OCT, such as additional contrast load for image acquisition and stenting involving the ostial and proximal LM, have also been overcome recently. In this review, we discuss the interpretation of OCT images and its clinical impact on the outcome of procedures along with current barriers to its use and newer paradigms in which OCT is starting to become a promising tool for the interventionalist and what can be expected for the immediate future in the imaging world.

Effect of proximal optimization technique on coronary bifurcation stent failure: Insights from the multicenter randomized PROPOT trial

OBJECTIVE

We investigated the effect of proximal optimization technique (POT) on coronary bifurcation stent failure (BSF) in cross-over stenting by comparing with the kissing balloon technique (KBT) in a multicenter randomized PROPOT trial.

BACKGROUND

POT is recommended due to increased certainty for optimal stent expansion and side branch (SB) wiring.

METHODS

We randomized 120 patients treated with crossover stenting into the POT group, which was followed by SB dilation (SBD), and the KBT group. Finally, 52 and 57 patients were analyzed by optical coherence tomography before SBD and at the final procedure, respectively. Composite BSF was defined as a maximal malapposition distance of >400 μm, or malapposed and SB-jailed strut rates of >5.95% and >21.4%, respectively.

RESULTS

Composite BSF before SBD in the POT and KBT groups was observed in 29% and 26% of patients, respectively. In the POT group, differences in stent volumetric index between the proximal and distal bifurcation (odds ratio [OR] 60.35, 95% confidential interval [CI] 0.13-0.93, p = 0.036) and between the proximal bifurcation and bifurcation core (OR: 3.68, 95% CI: 1.01-13.40, p = 0.048) were identified as independent risk factors. Composite BSF at final in 27% and 32%, and unplanned additional procedures in 38% and 25% were observed, respectively. Composite BSF before SBD was a risk factor for the former (OR: 6.33, 95% CI: 1.10-36.50, p = 0.039) and the latter (OR: 6.43, 95% CI: 1.25-33.10, p = 0.026) in the POT group.

CONCLUSION

POT did not result in a favorable trend in BSF. Insufficient expansion of the bifurcation core after POT was associated with BSF.

Cobalt exposure in relation to cardiovascular disease in the United States general population

Cobalt exposure has adverse health effects on the cardiovascular system in occupational and laboratory studies, but these effects have not been assessed in the general population. We aimed to determine whether serum cobalt levels had relationship with the prevalence of cardiovascular disease (CVD) in the general population. Using data from the National Health and Nutrition Examination Survey (NHANES) (2015-2016), we performed the cross-sectional study. We analyzed the baseline characteristics of 3389 participants (1623 men and 1766 women). Generalized linear models and restricted cubic spline plots curve were undertaken to elucidate the relationship. Stratified subgroup analysis was tested to exclude interaction between different variates and cobalt. Our results showed that the adjusted odds ratios (ORs) with 95% confidence intervals (CIs) for CVD prevalence across the quartiles of cobalt were 0.94 (0.67, 1.30), 1.55 (1.15, 2.10), and 1.74 (1.28, 2.35) compared with lowest quartile. The restricted cubic spline curve also suggested nonlinear and positive association between cobalt and CVD (P for nonlinearity = 0.007). In summary, our cross-sectional results verify that higher cobalt levels are associated with a higher prevalence of cardiovascular disease.

Diagnostic Performance of High-Resolution Intravascular Ultrasound for Abnormal Post-Stent Findings After Stent Implantation - A Comparison Study Between High-Resolution Intravascular Ultrasound and Optical Coherence Tomography

BACKGROUND

High-resolution intravascular ultrasound (HR-IVUS) is the most recently developed IVUS technology, which allows the detailed assessment of intravascular structures. The aim of this study was to evaluate the diagnostic performance of HR-IVUS in the detection of abnormal post-stent findings.Methods and Results:Patients with acute coronary syndrome underwent both HR-IVUS and optical coherence tomography (OCT) for post-stent evaluations. Quantitative measurements for stented segments and qualitative assessments for abnormal post-stent findings (stent edge dissection, intrastent tissue protrusion, and incomplete stent apposition [ISA]) were performed. Forty-seven patients underwent both HR-IVUS and OCT after stent implantation. HR-IVUS identified a larger minimal lumen area and a larger minimal lumen diameter than OCT (6.66±1.98 mm²vs. 5.61±1.79 mm²and 2.87±0.42 mm vs. 2.63±0.43 mm, respectively; both P<0.001). The sensitivity of HR-IVUS for the identification of stent edge dissection, intrastent tissue protrusion, and ISA were 20.0%, 48.9%, and 27.2%, respectively.

CONCLUSIONS

In terms of post-stent evaluation, the diagnostic performance of HR-IVUS remains insufficient. Abnormal post-stent findings might be underestimated when performing HR-IVUS due to its low sensitivity.

Current perspectives on bioresorbable scaffolds in coronary intervention and other fields

Introduction: The first-generation bioresorbable scaffolds (BRSs) had a large strut profile to compensate for the insufficient radial strength of bioresorbable polymer materials, resulting in higher scaffold thrombosis rates than conventional drug-eluting stents. To improve the clinical safety and efficacy, the new generation BRSs have been improved by optimal structure design, post-processing of bioresorbable polymer materials, or altering bioresorbable metallic alloys.Areas covered: This review summarizes the lessons learned from the first-generation BRS, updates the clinical outcomes of trials evaluating ABSORB bioresorbable vascular scaffold at long-term and bioresorbable metallic alloy-based devices, and examines recent outcomes of BRS treated in STEMI patients. This review also provides an overview of the current clinical data of seven BRSs manufactured in Asia, and of the BRSs extended application in other clinical arenas.Expert opinion: Drawbacks of the first-generation BRSs need to be addressed by the next generation of these stents with novel materials and technologies. Clinical research, including randomized controlled trials, are required to further evaluate BRSs application in coronary artery disease. The encouraging results of BRSs innovation applied in the peripheral arteries and gastrointestinal tracts support other potential clinical applications of BRS technology.

Optical Coherence Tomography of the Coronary Arteries

Intravascular imaging, particularly optical coherence tomography, has brought significant improvement in diagnostic and therapeutical approaches to coronary artery disease and has offered superior high-resolution visualization of coronary arteries. The ability to obtain images of intramural and transmural coronary structures allows the study of the process of atherosclerosis, effect of therapies, mechanism of acute coronary syndrome and stent failure, and performance of new devices and enables the interventional cardiologist to optimize the effect of percutaneous coronary intervention. In this review, we provide the summary of the latest published data on clinical use of optical coherence tomography as well as practical algorithm for optical coherence tomography-guided percutaneous coronary intervention for daily interventional practice.

Temporal changes of incomplete stent apposition during early phase after everolimus-eluting stent implantation: serial optical coherence tomography analyses at 2-week and 4-month

The healing process of acute incomplete stent apposition (ISA) in the early phase after stent implantation has not been well understood. We evaluated the temporal changes of ISA during the early phase after everolimus-eluting stent (EES) implantation using serial optical coherence tomography (OCT) analyses. Serial OCT examinations were performed immediately post-stenting and 2-week and 4-month after EES implantation for patients with ST-segment elevation myocardial infarction. At the most proximal cross-section of the implanted stent, the prevalence of ISA and maximum ISA distance were serially evaluated. In 45 patients with ST-segment elevation myocardial infarction, serial OCT analyses at 2-week and 4-month were performed. The prevalence of ISA gradually decreased over time, being 53.3% at baseline, 37.8% at 2-week follow-up, and 11.1% at 4-month follow-up (P < 0.001). The maximum ISA distance also decreased over time (P < 0.001). A receiver-operating curve analysis found that the optimal cut-off values of the baseline ISA distance for predicting persistent ISA at 2-week follow-up and 4-month follow-up were > 140 µm and > 215 µm, respectively. The baseline ISA distance was closely associated with the healing of ISA in the early phase after EES implantation. Maintaining the minimum ISA distance at post-stenting facilitates early phase healing of acute ISA.

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.

Relation between bioresorbable scaffold sizing using QCA-Dmax and long-term clinical outcomes in 1,232 patients from three study cohorts (ABSORB Cohort B, ABSORB EXTEND, and ABSORB II)

AIMS

This study sought to investigate the long-term clinical outcomes related to scaffold sizing based on quantitative coronary angiography.

METHODS AND RESULTS

A total of 1,248 patients who received Absorb bioresorbable scaffolds in the ABSORB Cohort B, ABSORB EXTEND, and ABSORB II trials were included in the analysis. The incidence of MACE (a composite of cardiac death, any myocardial infarction [MI], and ischaemia-driven target lesion revascularisation [ID-TLR]) was analysed according to the Dmax subclassification of oversized scaffold group versus non-oversized (any undersize) scaffold group. At three years, event rates were similar in both groups in MACE (9.4% vs. 9.8%, p=0.847), target vessel MI (5.2% vs. 4.8%, p=0.795), and ID-TLR (4.8% vs. 5.8%, p=0.445). Landmark analysis after one year showed that the non-oversized scaffold group had higher rates of MACE (3.2% vs. 6.9%, log-rank p=0.004), target vessel MI (0.7% vs. 2.7%, log-rank p=0.007), and ID-TLR (2.5% vs. 4.7%, log-rank p=0.041).

CONCLUSIONS

Implantation of an undersized scaffold was associated with a higher risk of MACE between one and three years, while in the previous report an oversized scaffold was associated with a higher risk of MACE up to one year. This implies different mechanisms for early and late events after scaffold implantation.