Influence of insulin resistance on in-stent restenosis in patients undergoing coronary drug-eluting stent implantation after long-term angiographic follow-up

OBJECTIVE

Previous studies have reported that insulin resistance is related to early in-stent restenosis (ISR) after coronary stenting. This study aimed to evaluate the influence of insulin resistance on the long-term angiographic outcome in patients undergoing coronary drug-eluting stent (DES) implantation.

MATERIALS AND METHODS

Within a single hospital-based cohort of patients (n=529) who underwent coronary DES implantation, angiographic follow-up was performed successfully for 417 study patients at 12-48 months after coronary stenting. ISR was defined as stenosis of at least 50% of the luminal diameter. Fasting plasma glucose and fasting plasma insulin were measured. Insulin resistance was expressed by the homeostasis model assessment index (HOMA-IRI).

RESULTS

Among the 417 patients who completed angiographic follow-up (mean 17.5±10.2 months), 58 patients (13.9%) had ISR whereas the remaining 359 patients (86.1%) did not have ISR. Patients with ISR had higher insulin resistance index (IRI) than nonrestenosis patients (P=0.004). Multiple logistic regression analysis (logit) showed that IRI was associated significantly with ISR (adjusted odds ratio 1.476, 95% confidence interval 1.227-1.776; P<0.001). In the nondiabetes subgroup of 309 patients, IRI was higher in patients with ISR than in nonrestenosis patients, as confirmed in a separate logit analysis (adjusted odds ratio 1.456, 95% confidence interval 1.152-1.839; P=0.002). Multiple linear regression analysis showed that IRI was associated significantly with in-stent diameter stenosis degree (P=0.043).

CONCLUSION

Insulin resistance was associated with ISR in patients undergoing coronary DES implantation at long-term angiographic follow-up.

Preclinical evaluation of a novel drug-eluting balloon in an animal model of in-stent stenosis

Despite advances in contemporary stent technology, in-stent restenosis (ISR) remains the major limitation following revascularization procedures. We developed a porcine model of ISR to specifically investigate the preclinical outcomes of a novel drug-eluting balloon (DEB) in this particular setting. Fifteen pigs received bare metal stents in each of the major coronary arteries for 28 days to induce neointimal growth. Following repeat angiography, animals were allocated to fourdifferent treatment groups. The control group consisted of a bare angioplasty catheter, while the Pantera Lux™ (3.0 µg/mm2 paclitaxel) (30 s inflation) was compared to two consecutive deployments of the Pantera Lux™ (60 s inflation each) and the commercial SeQuent® Please balloon (60 s inflation). Twenty-eight days following balloon deployment, the animals underwent repeat angiography and were subsequently sacrificed for histopathologic assessment. There was a trend in reduction of percent diameter stenosis in the DEB group versus control (13.9% vs. 20.4%), while longer inflation duration or consecutive DEB deployment had no additional growth-limiting effect. Neointimal thickness was reduced from 0.38 ± 0.13 to 0.30 ± 0.09 mm in the control versus DEB group. All DEB groups showed delayed vascular healing characterized by dose-dependent increases in fibrin deposition and neointimal cell vacuity. Investigation of DEB in a porcine model of ISR is feasible and more accurately represents human disease conditions. The magnitude of neointima suppression is lower than that observed in non-diseased animal models and is accompanied by delayed vascular healing.

Long-term outcomes after the percutaneous treatment of drug-eluting stent restenosis

OBJECTIVES

This study sought to evaluate the long-term angiographic and clinical outcomes after the treatment of drug-eluting stent in-stent restenosis (DES-ISR) based on the angiographic pattern of restenosis.

BACKGROUND

Long-term outcomes after percutaneous treatment of DES-ISR are unclear.

METHODS

This study performed a retrospective analysis of 481 consecutive de novo DES-ISR lesions (n = 392) treated percutaneously between August 2002 and July 2007. The lesions were divided based on the pattern of restenosis: focal (305; 63.4%), diffuse (120; 24.9%), and occlusive (56; 11.6%).

RESULTS

The majority (65%) of patients had angina or ischemia on presentation and 13% had an acute coronary syndrome. Angiographic follow-up after treatment of DES-ISR was available in 65.5% of lesions. A second angiographic restenosis occurred in 29.1% of the focal group, 45.8% (p = 0.007) of the diffuse, and 65.6% (p < 0.0001) of the occlusive. The pattern of DES-ISR predicted the pattern of recurrence: occlusive reoccluded in 66.7%; diffuse recurred as diffuse or occlusive in 57.9%; focal as focal in 67.2%. During a median follow-up of 2.97 years (interquartile range: 2.37 to 3.89), major adverse cardiac events occurred in 32.8% of patients with no significant differences among the focal, diffuse, and occlusive groups (30.9%, 38.7%, 31.1%; p = 0.38). Diffuse restenosis was associated with a significantly higher target lesion revascularization rate compared with focal (27.1% vs. 15.8%; p = 0.008). A disparity between restenosis (65.6%) and target lesion revascularization (18.5%) rates for occlusive DES-ISR suggests that as many recurrent restenoses were occlusive, they were not retreated.

CONCLUSIONS

DES-ISR identifies a high-risk cohort that is at an increased risk of events, in particular repeat revascularization, during long-term follow-up. The initial pattern of restenosis is the most important predictor of recurrent restenosis or the need for subsequent reintervention.

Comparison of plain balloon and cutting balloon angioplasty for the treatment of restenosis with drug-eluting stents vs bare metal stents

BACKGROUND

The efficacy of cutting or plain balloon angioplasty (CBA or PBA) has not been analyzed for the treatment of drug-eluting stent (DES) restenosis vs bare metal stent (BMS) restenosis.

METHODS AND RESULTS

The 252 in-stent restenosis (ISR) lesions in 224 consecutive patients treated by CBA (n=167) or PBA (n=85) between July 2002 and December 2007 were analyzed. At 6-month angiographic and 12-month clinical follow-up, CBA and PBA showed similar efficacies: repeat-ISR (37.0% vs 37.8%, P=0.90), late loss (0.62+/-0.60 vs 0.61+/-0.47 mm, P=0.92), and target lesion revascularization (18.3% vs 22.4%, P=0.50). This comparable efficacy was maintained for treatment in the DES-ISR and BMS-ISR subgroups. However, target lesion-related myocardial infarction (n=9) occurred more frequently in the CBA than in the PBA arm (6.2% vs 0%, P=0.03), most of which developed early after ISR treatment (n=7; 54+/-26 days). Independent predictors of repeat-ISR were diffuse ISR and smaller pretreatment minimal lumen diameter, both of which might imply heavier plaque burden in the ISR group.

CONCLUSIONS

Plain or cutting balloon angioplasty for ISR seems to be comparable, as the angiographic or clinical endpoints were not affected by initial stent type but by parameters related to the plaque burden of the ISR lesion. However, CBA might be associated with higher risk of myocardial infarction than PBA, suggesting more attention to dual-antiplatelet therapy after its use for ISR.