Implications of the "watermelon seeding" phenomenon during coronary interventions for in-stent restenosis

In-Stent Restenosis

In-stent restenosis (ISR) remains a potential complication after percutaneous coronary intervention, even in the era of drug-eluting stents, and its treatment remains suboptimal. Neoatherosclerosis is an important component of the pathology of ISR and is accelerated in drug-eluting stents compared with bare-metal stents. Coronary angiography is the gold standard for evaluating the morphology of ISR, although computed tomography angiography is emerging as an alternative noninvasive modality to evaluate the presence of ISR. Drug-coated balloons and stent reimplantation are the current mainstays of treatment for ISR, and the choice of treatment should be based on clinical background and lesion morphology.

Management of in-stent restenosis

In-stent restenosis (ISR) remains the most common cause of stent failure after percutaneous coronary intervention (PCI). Recent data suggest that ISR-PCI accounts for 5-10% of all PCI procedures performed in current clinical practice. This State-of-the-Art review will primarily focus on the management of ISR but will begin by briefly discussing diagnosis and classification. We then move on to detail the evidence base underpinning the various therapeutic strategies for ISR before finishing with a proposed ISR management algorithm based on current scientific data.

Endovascular management of nutcracker syndrome in an adolescent patient population

BACKGROUND

Nutcracker syndrome is defined as left renal vein compression with concomitant clinical symptoms that include flank pain and hematuria. Historically, pediatric and adolescent patients with mild symptoms of nutcracker syndrome were simply observed while those with more severe symptoms underwent left renal vein transposition. Endovascular stenting of the left renal vein is a potentially efficacious and less invasive alternative for managing nutcracker syndrome in adolescents.

OBJECTIVE

The purpose of this study was to investigate the technical feasibility, efficacy and safety of left renal vein stenting in adolescents with nutcracker syndrome.

MATERIALS AND METHODS

We conducted a retrospective review of electronic medical records and imaging archives to identify adolescents undergoing endovascular stenting for nutcracker syndrome. We reviewed patient demographics including age, gender, presenting symptoms and diagnostic imaging findings. We compared pre- and post-stent deployment intravascular ultrasound (IVUS) and venography and evaluated patient symptoms in clinic up to 6 months following stent placement.

RESULTS

Ten patients (average age 16 years, range 12-20 years) underwent 13 procedures. Initial symptoms included pain (n=10) and gross hematuria (n=5). Diagnostic imaging studies included CT abdomen pelvis (n=8), retroperitoneal US (n=6), MRI abdomen/pelvis (n=4), scrotal US (n=2), pelvic US (n=1) and renal Doppler US (n=2). Venography and IVUS demonstrated venous collaterals, proximal blanching at the left-renal-vein-IVC junction, pre-stenotic dilation and intraluminal compression. Most patients (n=9) experienced symptomatic resolution; however, three patients required reintervention to achieve asymptomatic status. No periprocedural complications occurred.

CONCLUSION

In this carefully selected adolescent cohort, left renal vein stenting for nutcracker syndrome was often technically feasible, safe and effective in symptom management.

Procedural and 1-year clinical outcomes of orbital atherectomy for treatment of coronary in-stent restenosis: A single-center, retrospective study

OBJECTIVES

We evaluated the procedural and 1-year clinical outcomes of orbital atherectomy (OA) for treatment of coronary in-stent restenosis (ISR).

BACKGROUND

The optimal treatment for ISR remains uncertain. While rotational and laser atherectomy have been used as neointimal debulking techniques for ISR, there have been few reports on OA for ISR.

METHODS

This is a retrospective observational study of consecutive patients who underwent percutaneous coronary intervention (PCI) for ISR with OA in Mount Sinai catheterization laboratory between November 2013 and January 2018. Procedural success was defined as angiographic success without in-hospital major adverse cardiac events (MACE; the composite of all-cause death, myocardial infarction [MI], or target vessel revascularization). Clinical outcomes were assessed at 1 month and 12 months postprocedure.

RESULTS

A total of 87 patients were included in the study. All 87 patients were treated with OA, after which 49 (56.3%) patients also received new drug-eluting stents. Angiographic success was achieved in 87 (100%) patients and procedural success was achieved in 79 (90.8%) patients. In-hospital MACE occurred in 8 (9.2%) patients, all due to periprocedural non-Q-wave MI. Acute lumen gain was 1.19 ± 0.57 mm after OA plus balloon angioplasty and 1.75 ± 0.50 mm after stent placement. MACE within 1 year occurred in 17 (19.5%) patients.

CONCLUSIONS

OA for ISR was performed with favorable procedural and 1-year clinical outcomes. Randomized trials are warranted to determine whether OA improves the poor prognosis of patients with ISR treated without debulking.

Rotational atherectomy for the management of undilatable in-stent restenosis with single or multiple stent layers

BACKGROUND

There is no consensus on the best treatment of undilatable coronary in-stent restenosis (ISR) regardless of the number of stent layers. We aimed to evaluate the procedural and clinical outcomes of rotational atherectomy (RA) to treat undilatable coronary ISR with single or multiple stent layers.

METHODS

We retrospectively evaluated consecutive patients treated with RA for undilatable ISR with single or multiple stent layers in the Mount Sinai catheterization laboratory between January 2016 and September 2018. Procedural success was defined as angiographic success without in-hospital major adverse cardiac events (MACE): a composite of death, myocardial infarction (MI), and target lesion revascularization (TLR). Clinical outcomes were assessed at one-year post-procedure.

RESULTS

A total of 26 patients were included in the study, in which 18 (69.2%) patients were with multiple stent layers. After RA, 9 (34.6%) were received a new drug-eluting stent, and 6 (23.1%) were treated with intravascular brachytherapy. Angiographic success was achieved in 24 (92.3%) patients, and procedural success was achieved in 22 (84.6%) patients. In-hospital MACE occurred in 4 (15.4%) patients, all due to periprocedural non-Q wave MI. Within one year, MACE occurred in 9 (34.6%) patients with 5 (19.2%) TLR.

CONCLUSIONS

RA for undilatable ISR with single or multiple stent layers was performed with favorable procedural outcomes and a relatively high MACE rate driven by TLR within one year.

Scoring balloon predilation before bioresorbable vascular scaffold implantation in patients with in-stent restenosis: the RIBS VI 'scoring' study

BACKGROUND

Currently drug-eluting stents (DES) and drug-eluting balloons are recommended in patients with in-stent restenosis (ISR). However, the efficacy of bioresorbable vascular scaffolds (BVS) after scoring balloon (SCB) predilation in these patients is unknown.

METHODS

RIBS VI (NCT02672878) and RIBS VI 'Scoring' (NCT03069066) are prospective multicentre studies assessing the value of BVS in patients with ISR. Inclusion and exclusion criteria were identical in both studies. Results of conventional BVS implantation (112 patients) were compared with those obtained with systematic SCB therapy before BVS (108 patients). Angiographic follow-up was scheduled for all patients.

RESULTS

On late angiography (93% of eligible patients) the in-segment minimal lumen diameter (primary end-point) (1.88 ± 0.5 vs. 1.90 ± 0.4 mm, P = 0.81), % diameter stenosis (28 ± 17 vs. 29 ± 15%), late lumen loss (0.23 ± 0.4 vs. 0.22 ± 0.4 mm) and binary restenosis rate (8.5 vs. 9.3%) were similar in the conventional BVS and SCB + BVS groups, respectively. At 1-year follow-up (100% of patients) target lesion revascularization (TLR) requirement (9.8 vs. 11.1%) was similar with the two strategies. Freedom from cardiac death, myocardial infarction and TLR was 88% and 87%, respectively. Results remained unchanged after adjusting for potential baseline confounders and were consistent in 10 prespecified subgroups.

CONCLUSION

This study suggests that results of conventional BVS implantation in patients with ISR are not improved by systematic predilation with SCB. ClinicalTrials.gov ID: NCT02672878 (RIBS VI) and NCT03069066 (RIBS VI 'Scoring').

Restenosis of Drug-Eluting Stents

Despite on-going evolution and iteration of drug-eluting stent (DES) technology, the prevalence of in-stent restenosis (ISR) remains relatively unchanged, encompassing ≈10% of percutaneous coronary interventions. The mechanism of ISR is multifactorial, including biological, mechanical, patient, and operator-related factors. The main mechanical contributors are stent underexpansion or fracture, while biological factors include local inflammation leading to aggressive neointimal proliferation and late neoatherosclerosis. Intracoronary imaging is critical to identify the mechanism of ISR and tailor therapy accordingly. The presentation of DES-ISR is not benign and is challenging for optimal treatment. Among the proposed treatment modalities are scoring and high-pressure balloons, percutaneous coronary intervention with additional DES, atheroablative therapies by laser or mechanical atherectomy, drug-coated balloons, vascular brachytherapy, and surgical revascularization. We propose a new classification for ISR that differentiates among mechanical, biological, and mixed etiologies. Stratifying ISR by mechanism guides individualized treatment of DES-ISR to improve clinical outcomes. An algorithmic approach, guided by intracoronary imaging, for the treatment of DES-ISR, is recommended based on the specific cause of restenosis.

Therapeutic Options for In-Stent Restenosis

PURPOSE OF REVIEW

In-stent restenosis (ISR) is a complex disease process that became apparent shortly after the introduction of stents into clinical practice. This review seeks to define in-stent restenosis (ISR) as well as to summarize the major treatment options that have been developed and studied over the past two decades.

RECENT FINDINGS

Recent developments in drug-coated balloons and bioresorbable vascular scaffolds have added new potential treatments for ISR. Two recent network meta-analyses performed a head-to-head comparison of all the various treatment modalities in order to identify the best approach to management of ISR. Current data suggests that repeat stenting with second-generation drug-eluting stents is most likely to lead to the best angiographic and clinical outcomes. In situations where repeat stenting is not preferable, drug-coated balloon therapy seems to be a reasonably effective alternative.

Current Management of In-Stent Restenosis

Despite the advent of the drug-eluting stents (DES) and improved stent design, in-stent restenosis (ISR) remains a challenging problem. The currently available options for treatment of ISR include angioplasty alone, repeat stenting with DES or drug-coated balloons. Several recent studies have compared the available options for treating ISR in an attempt to identify the preferred therapeutic strategy. In this review, we will discuss the currently available therapeutic strategies for the management of patients with ISR and the evidence supporting their use.

Balloon pin-hole rupture during percutaneous coronary intervention for recurrent, calcified in-stent restenosis: A case report

Percutaneous coronary intervention (PCI) for patients with in-stent restenosis (ISR) is generally considered safe and effective. However, due to increased tissue hardness, PCI for calcified intra-stent ISR is technically challenging. Here, we report severe angioplasty-related complications in a patient presenting with calcified, recurrent ISR following PCI. After receiving drug-coated balloon (DCB) angioplasty for an initial ISR, the patient developed recurrent ISR during the follow-up period. Intravascular imaging revealed intra-stent calcifications and balloon angioplasty was subsequently performed. During the angioplasty, a pin-hole balloon rupture occurred, consequently causing coronary dissection as visualized by intravascular imaging. To prevent acute coronary occlusion, stent implantation was required. The present case report suggests that, following detection of intra-stent calcified stenosis, both careful balloon inflation as well as optimal ablation device selection are required to prevent potential complications and obtain successful procedural outcomes.

Efficacy of Drug-Eluting Balloons for Patients With In-Stent Restenosis: A Meta-Analysis of 8 Randomized Controlled Trials

The optimal treatment for in-stent restenosis (ISR) of both bare-metal stent (BMS) and drug-eluting stent (DES) is currently unclear. The aim of this meta-analysis was to assess the role of drug-eluting balloon (DEB) as an optional treatment for ISR. We searched PubMed, MEDLINE, EMBASE, BIOS, and Web of Science from 2005 to July 2014. Eight studies, enrolling 1413 patients were included. Main end points were late lumen loss (LLL), binary in-segment restenosis (BR), major adverse cardiac events (MACEs), target lesion revascularization (TLR), death, myocardial infarction (MI), and stent thrombosis (ST). When compared to plain old balloon angioplasty (POBA), DEB treatment significantly reduced the risk of MACE (risk rato [RR] 0.37, P < .01), death (RR 0.44, P = .04), TLR (RR 0.27, P < .01), BR (RR [95% CI]: 0.23[0.12 to 0.43], P < .01) and associated with better outcomes of LLL ( 0.50 [ 0.65 to 0.35] mm, P < .01). However, the differences were not significant between DEB treatment and DES treatment in all primary and secondary end points. The DEB was a better option to treat ISR when compared to POBA. However, it had similar effects as DES.

Impact of rapid ventricular pacing during TAVI on microvascular tissue perfusion

BACKGROUND

Rapid ventricular pacing (RVP) is an established technique to temporarily reduce left ventricular output during transcatheter aortic valve implantation (TAVI). The purpose of this study was to evaluate the impact of RVP on microvascular tissue perfusion (MTP) in patients undergoing TAVI.

METHODS AND RESULTS

We studied 42 patients (mean age 81.8 ± 6.9 years, n = 18 females. EuroSCORE 33 ± 12 %) during TAVI. MTP was analyzed using Sidestream-Darkfield imaging, of the sublingual microvasculature. Microvascular flow index (MFI) was continuously measured in small (10-25 μm)- and medium (26-50 μm)-sized vessels, starting 10 s before and ending 12 s after RVP. Further, perfused capillary density, total vessel density and the proportion of perfused vessels were assessed. After a mean RVP duration of 14.3 s (range 6-29), mean arterial pressure decreased from 68 ± 05 to 40 ± 7 mmHg (p < 0.001). This was associated with a significant decrease of MFI in small- and medium-sized vessels from 2.29 ± 0.64 and 2.36 ± 0.6 to 0.87 ± 0.66 (p < 0.001) and 1.0 ± 0.83 (p < 0.001), respectively. MFI remained significantly below baseline values (small: 1.75 ± 0.8, p = 0.001 vs. baseline; medium: 1.77 ± 0.85; p = 0.005 vs. baseline) at 12 s after end of RVP.

CONCLUSIONS

The study demonstrates a time-dependent effect of RVP on microflow, leading to 50 and 25 % of baseline at 8 and 18 s of RVP, respectively. In a substantial proportion of patients, RVP is associated with microcirculatory arrest and a delayed recovery of microflow. Although the impact of these findings on outcome is yet unclear, TAVI operators should be aware of the potentially adverse effects of even short periods of RVP.

Current treatment of in-stent restenosis

Management of patients with in-stent restenosis (ISR) remains an important clinical problem. Although drug-eluting stents (DES) have drastically reduced the incidence of ISR, treatment of DES-ISR is particularly challenging. ISR mainly results from aggressive neointimal proliferation, but recent data also suggest that neoatherosclerosis may play an important pathophysiological role. Intracoronary imaging provides unique insights to unravel the underlying substrate of ISR and may be used to guide repeated interventions. In this paper, we systematically reviewed clinical trial data with currently available therapeutic modalities, including DES and drug-coated balloons, in patients presenting with ISR within bare-metal stents or DES.

Impact of different re-stenting strategies on expansion of a drug-eluting stent implanted to treat bare-metal stent restenosis

We used intravascular ultrasound (IVUS) to compare the expansion of drug-eluting stents (DES) implanted to treat bare-metal stent (BMS) restenosis after 3 common re-stenting strategies. A total of 80 consecutive BMS restenotic targets were re-stented either directly (n = 30, group 1) or after low-pressure (<8 atm) pre-dilation with an undersize regular balloon (n = 16, group 2) or after high-pressure (>12 atm) pre-dilation with a semicompliant balloon the same or greater diameter as the original BMS diameter (n = 34, group 3). More patients from groups 2 and 3 had diabetes mellitus. The targets in group 1 were more proximal and focal. Lesions from groups 2 and 3 were more severe. The size and deployment pressure of the DESs and the achieved angiographic results were all similar. The post-intervention minimum stent area and the percentage of expansion of DES (minimum stent area/distal reference lumen area x 100%) were, however, both significantly larger in group 3 (6.4 +/- 1.5 mm(2) in group 3 vs 5.6 +/- 1.6 mm(2) in group 1 vs 4.4 +/- 1.4 mm(2) in group 2, p <0.001; and 88 +/- 30% in group 3 vs 74 +/- 14% in group 1 vs 73 +/- 23% in group 2, p = 0.021). A post-intervention minimum stent area <5.0 mm(2) was seen in only 3 lesions in group 3 (8.8%) versus 14 in group 1 (46.7%) and 11 in group 2 (68.8%; adjusted odds ratio 0.11, 95% confidence interval 0.03 to 0.38, p <0.001). Overall, the acute lumen gain was mainly from BMS re-expansion; however, the BMS volume increased the most in group 3 (p <0.001). In conclusion, high-pressure pre-dilation leads to superior post-intervention expansion of DESs implanted to treat BMS restenosis, regardless of the original expansion because of the greater BMS re-expansion.