Serial Intravascular Ultrasound Findings After Treatment of Chronic Total Occlusions Using Drug-Eluting Stents

Self-Apposing Stents in Coronary Chronic Total Occlusions: A Pilot Study

OBJECTIVES

This pilot study assessed the 12-month angiographic and clinical outcomes of self-apposing (SA) stents in patients undergoing chronic total occlusion (CTO) percutaneous coronary intervention (PCI).

BACKGROUND

Self-apposing (SA) stents may decrease incomplete strut apposition and stent strut coverage that are common after CTO PCI.

METHODS

We compared 20 patients who underwent CTO PCI using SA drug-eluting stents (DESs) with 20 matched control patients who underwent CTO PCI using balloon-expandable (BE)-DESs. All patients were followed up clinically for 12 months and had coronary angiography with optical coherence tomography at the end of the follow-up period. The primary end points were stent strut malapposition and strut coverage. The secondary end point was composite major adverse cardiovascular events (MACEs) at 12 months.

RESULTS

Both groups had high prevalence of diabetes mellitus, and most of the treated lesions were complex, with 62% having a J-CTO score of ≥3. All CTO PCI techniques were allowed for recanalisation, and 75% of the procedures were guided by intravascular ultrasound. At 12 months, the SA-DES group had fewer malapposed struts (0% [interquartile range (IQR) 0%-0%] vs 4.5% [IQR 0%-20%]; p<0.001) and uncovered struts (0.08% [IQR 0%-1.6%] vs 8.2% [IQR 0%-16%]; p<0.001). However, they showed significantly higher rates of MACEs due to clinically-driven target lesion revascularisation (45% vs 15%; p=0.038).

CONCLUSIONS

In this pilot study, compared with conventional BE-DESs, SA-DESs used in CTO PCI were associated with fewer malapposed and uncovered stent struts but also with significantly higher rates of in-stent restenosis and MACEs, mainly caused by clinically driven target lesion revascularisation.

Impact of Reference Mismatch on Procedure Outcomes of Percutaneous Coronary Intervention

A significant mismatch between proximal and distal reference lumen diameters of the target lesion may pose challenges during percutaneous coronary intervention (PCI) and therefore influence the outcomes. We investigated total 1706 lesions underwent IVUS guided percutaneous coronary intervention, that were divided into 2 groups, including 411 lesions in Mismatch group and 1295 lesions in Non-Mismatch group. After propensity score matching, 397 lesions in each group were selected for final data set. The analysis showed that Mismatch group PCI required more frequently use of post-stenting optimization (79.6% vs 53.9%, P < .001) using higher max pressure (19.5 ± 3.9 vs 16.7 ± 3.7 atm, P < .001). Besides, Mismatch group also encountered more PCI major complications (7.8% vs 4.0%, P = .024) and lower procedure success rate (91.4% vs 95.5%, P = .022). On final angiogram, Mismatch group had smaller minimum lumen diameter (2.62 ± .45 vs 2.90 ± .57 mm, P < .001) and lower angiographic success rate (93.2% vs 96.7%, P = .023). On final IVUS, Mismatch group had higher rate of incomplete stent apposition and stent edge dissection (6.3% vs 3.0%, P = .029 and 2.5% vs .5%, P = .021, respectively). In conclusion, reference mismatch posed significant challenging during PCI that led to unfavorable procedural outcomes. These impacts may translate into long-term clinical implications that need to be addressed in future studies.

Fate of lumen size in distal coronary segment following successful chronic total occlusion recanalization

BACKGROUND

Restoration of anterograde blood flow leads to alterations in vascular wall stress that may influence lumen size distal to chronic total occlusion (CTO) lesions. We sought to assess changes in lumen diameter of segments distal to the stent segment of successfully recanalized CTO.

METHODS

We analyzed 507 consecutive CTO cases with stent implantation that underwent follow-up angiography at a single high-volume center (mean follow-up of 13.5 months). Segments ≤40 mm distal to the stent edge were analyzed using quantitative coronary angiography.

RESULTS

At follow-up, lumen diameters significantly increased; diameter changes of 0.26 ± 0.47 (percent diameter change of 18.2%) at 5 mm distal, mean lumen diameter changes of 0.23 ± 0.35 (14.3%) and minimal lumen diameter changes of 0.22 ± 0.80 (24.7%) (all p < 0.001). Lumen enlargement was similar between visually shrunken and stenosed vessels (degree of stenosis ≥20% with luminal irregularities) distal to stents; 5 mm distal (0.32 ± 0.48 vs. 0.30 ± 0.48, p = 0.76), mean lumen diameter changes (0.26 ± 0.37mm vs. 0.26±0.33 mm, p = 0.94), minimal lumen diameter changes (0.28 ± 0.43 mm vs. 0.22 ± 1.30 mm, p = 0.48). There was no association between degree of in-stent narrowing and changes in distal lumen diameter (Spearman r = -0.02, p = 0.59). Multivariate logistic regression for the predictors of greater lumen enlargement indicated that patients with left ventricle dysfunction (ejection fraction ≤45%) had greater enlargement [odds ratio (OR): 2.53, 95% confidence interval (CI): 1.23-5.23, p = 0.01]. Conversely, a low hematocrit (male <40%, and female <35%) was associated with attenuated lumen enlargement (OR: 0.68 95% CI: 0.47-0.98; p = 0.04).

CONCLUSIONS

Lumen diameter distal to CTO lesions significantly increased following successful revascularization, regardless of diseased status of the distal bed or degree of in-stent narrowing. These findings implicate appropriate determination of stent size, stent coverage length, as well as management strategies of distal vessels.

Coronary physiology before and after chronic total occlusion treatment: what does it tell us?

Studies performed in the last two decades demonstrate that after successful percutaneous coronary intervention (PCI) of a chronically occluded coronary artery, the physiology of the chronic total occlusion (CTO) vessel and dependent microvasculature does not normalise immediately but improves significantly over time. Generally, there is an increase in fractional flow reserve (FFR) in the CTO artery, a decrease in collateral blood supply and an increase in FFR in the donor artery accompanied by an increase in blood flow and decrease in microvascular resistance in the myocardium supplied by the CTO vessel. Analogous to these physiological changes, positive remodelling of the distal CTO artery also occurs over time, and intravascular imaging can be helpful for analysing distal vessel parameters. Follow-up coronary angiography with physiological measurements after several weeks to months can be helpful and informative in a subset of patients in order to decide upon the necessity for treatment of residual coronary artery stenosis in the vessel distal to the CTO or in the contralateral donor artery, as well as in deciding whether stent optimisation is indicated. We suggest that such physiological guidance of CTO procedures avoids unnecessary overtreatment during the initial procedure, guides interventions at follow-up, and improves our understanding of what PCI in CTO means.

Imaging Characteristics of Mismatch Lesions: An Angiographic and Intravascular Ultrasound Analysis of 1369 Coronary Lesions

OBJECTIVES

To evaluate the angiographic and intravascular ultrasound (IVUS) characteristics of coronary mismatch lesions.

BACKGROUND

Better understanding about the characteristics of mismatch lesions may help to achieve more accurate lesion assessment and, thereby, to improve the outcomes of percutaneous coronary intervention (PCI).

METHODS

Angiographic and IVUS data from 1369 lesions were analyzed. Mismatch lesion was defined as the difference between proximal and distal reference lumen diameters of ≥1.0 mm or ≥30% of the distal reference lumen diameter.

RESULTS

The incidence of mismatch lesions was 20.1% (275/1369). Compared to nonmismatch group, mismatch group had longer lesions (21.3 [6.4] mm vs 18.4 [6.4] mm, P < .001) with smaller minimum lumen diameter (0.87 [0.29] mm vs 1.10 [0.31] mm, P < .001) and more severe diameter stenosis (78.8% [9.2%] vs 66.3% [10.3%], P < .001). On IVUS, mismatch group had larger lumen area (18.7 [5.0] vs 15.8 [5.1] mm², P < .001) but lower plaque burden at the proximal reference segment (41.0% [9.2%] vs 45.7% [9.9%], P < .001) and smaller lumen area (4.83 [1.89] vs 7.36 [2.89] mm, P < .001) but higher plaque burden at the distal reference segment (42.9% [10.4%] vs 41.4% [10.1%], P = .023). Multivariable logistic regression analysis showed that mismatch lesions were frequently accompanied by diffuse lesions (odds ratio [OR] = 2.50; 95% confidence interval [CI]: 1.83-3.40; P < .001), bifurcation lesions (OR = 5.83; 95% CI: 4.40-7.74; P < .001), and lesions with a low TIMI flow grade (OR = 1.70; 95% CI: 1.08-2.67; P = .022) or severe diameter stenosis (OR = 3.05; 95% CI: 2.10-4.43; P < .001).

CONCLUSIONS

Mismatch lesions are quite common and characterized by greater lesion complexity compared with nonmismatch lesions. Further studies may be necessary to address the impact of this lesion type on the outcome of PCI.

Meta-analysis and systematic review of intravascular ultrasound versus angiography-guided drug eluting stent implantation in left main coronary disease in 4592 patients

Background

Although several meta-analyses have demonstrated the utility of intravascular ultrasound (IVUS) in guiding drug-eluting stent (DES) implantation compared to angiography-guidance, there has been a dearth of evidence in the left main coronary artery (LMCA) lesion subset.

Methods

We performed a meta-analysis to compare clinical outcomes of IVUS versus conventional angiography guidance during implantation of DES for patients with LMCA disease. Pubmed, Cochrane Library, Embase were searched.

Results

A total of 1002 publications were reviewed; and finally, seven clinical studies - one prospective randomized controlled trial and six observational studies with 4592 patients (1907 IVUS-guided and 2685 angiography-guided) - were included in the meta-analysis. IVUS guidance was associated with a significant reduction in major adverse cardiac events (relative ratio [RR] 95% CI 0.61; 95% confidence interval [CI] 0.53 to 0.70; P < 0.001), all-cause death (RR 0.55; 95% CI 0.42 to 0.71; P < 0.001), cardiac death (RR 0.45; 95% CI 0.32 to 0.62; P < 0.001), myocardial infarction (RR 0.66; 95% CI 0.55 to 0.80; P < 0.001), and stent thrombosis (RR 0.48; 95% CI 0.27 to 0.84; P = 0.01) compared with angiographic guidance. However, there was no significant difference regarding target lesion revascularization (RR 0.60; 95% CI 0.31 to 1.18; P = 0.099) and target vessel revascularization (RR 0.64; 95% CI 0.26 to 1.56; P = 0. 322).

Conclusions

Compared to angiographic guidance, IVUS-guided DES implantation was associated with better clinical outcomes for patients with LMCA lesions, especially hard endpoints of death, myocardial infarction, and stent thrombosis.

Procedural and Long-Term Outcomes of Bioresorbable Scaffolds Versus Drug-Eluting Stents in Chronic Total Occlusions: The BONITO Registry (Bioresorbable Scaffolds Versus Drug-Eluting Stents in Chronic Total Occlusions)

BACKGROUND

There is little evidence regarding the efficacy and safety of bioresorbable scaffolds (BRS) for the percutaneous treatment of chronic total occlusions.

METHODS AND RESULTS

We performed a multicenter registry of consecutive chronic total occlusion patients treated with BRS (Absorb; Abbott Vascular) and second-generation drug-eluting stents (DES) at 5 institutions. Long-term target-vessel failure (a composite of cardiac death, target-vessel myocardial infarction, and ischemia-driven target-lesion revascularization) was the primary end point. Inverse probability of treatment weight-adjusted Cox regression was used to account for pretreatment differences between the 2 groups. A total of 537 patients (n=153 BRS; n=384 DES) were included. BRS patients were younger and had lower prevalence of comorbidities. Overall mean Japan-Chronic Total Occlusion (J-CTO) score was 1.43±1.16, with no differences between groups. Procedural success was achieved in 99.3% and 96.6% of BRS- and DES-treated patients, respectively (P=0.07). At a median follow-up of 703 days, there were no differences in target-vessel failure between BRS and DES (4.6% versus 7.7%; P=0.21). By adjusted Cox regression analysis, there were still no significant differences between BRS and DES (hazard ratio, 1.54; 95% confidence interval, 0.69-3.72; P=0.34). However, secondary analyses suggested a signal toward higher ischemia-driven target-lesion revascularization with BRS.

CONCLUSIONS

Implantation of BRS versus second-generation DES in chronic total occlusion was associated with similar risk of target-vessel failure at long-term follow-up. However, a signal toward increased ischemia-driven target-lesion revascularization with BRS was observed. Large randomized studies should confirm these findings.