Mechanism of lumen gain during coronary stent deployment in diabetic patients compared with non-diabetic patients

Everolimus Eluting Stents in Patients with Diabetes Mellitus and Chronic Kidney Disease: Insights from the TUXEDO Trial

BACKGROUND

Patients with diabetes and those with chronic kidney disease (CKD) are at increased risk of cardiovascular events. Everolimus eluting stents (EES) have been shown to be superior to paclitaxel eluting stents (PES) in patients with diabetes. However, it is not known if EES is as beneficial in diabetic patients with CKD compared with those without CKD.

METHODS AND RESULTS

Patients enrolled in the TUXEDO-India trial, which is a clinical trial of patients with diabetes and coronary artery disease (CAD) randomly assigned to EES vs. thin-strut PES (Taxus Element), with data on baseline renal function were selected. CKD was defined as an estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m² using the Cockcroft-Gault formula. Primary outcome was target vessel failure (TVF-defined as cardiac death, TV myocardial infarction (MI) or ischemia driven TV revascularization) at 1 year. Various secondary outcomes including stent thrombosis were evaluated. Among the 1821 patients with diabetes included in this analysis, 344 (19%) had CKD. In a propensity score adjusted analysis, patients with CKD had a significant increase in MACE (HR = 2.02; 95% CI 1.17-3.50; P = 0.01); death/MI/TVR (HR = 1.99; 95% CI 1.18-3.34; P = 0.009); death/MI (HR = 2.31; 95% CI 1.30-4.08; P = 0.004); cardiac death/MI (HR = 2.40; 95% CI 1.31-4.42; P = 0.005); death (HR = 2.88; 95% CI 1.35-6.13; P = 0.006) driven by an increase in cardiac death (HR = 3.33; 95% CI 1.42-7.83; P = 0.006) when compared with those without CKD. However, stent related events (TV-MI, TVR, TLR and stent thrombosis) were not different between CKD and non CKD groups. A significant interaction between CKD status and stent type (EES vs. PES) was noted for the outcomes of TVF (P_interaction = 0.046), MACE (P_interaction = 0.02), cardiac death or MI (P_interaction = 0.05), non-target vessel related MI (P_interaction = 0.04), non-Q-wave MI (P_interaction = 0.03) and deaths/MI/TVR (P_interaction = 0.04) such that EES was superior to PES in the non-CKD cohort but not in the CKD cohort.

CONCLUSIONS

In subjects with diabetes, CKD is an independent predictor of adverse cardiovascular outcomes including increased risk of death driven largely by non-stent related events. While EES was superior to PES in patients without CKD, this was not the case in those with CKD (Clinical Trials Registry-India number, CTRI/2011/06/001830).

Impact of diabetes mellitus on vessel response in the drug-eluting stent era: pooled volumetric intravascular ultrasound analyses

BACKGROUND

Exaggerated neointimal hyperplasia is considered as the primary mechanism for increased restenosis in patients with diabetes mellitus (DM) treated with bare-metal stent. However, the vessel response in DM and non-DM treated with different drug-eluting stents (DES) has not been systematically evaluated.

METHODS AND RESULTS

We investigated 3D intravascular ultrasound (postprocedure and 6 to 9 months) in 971 patients (267 with DM and 704 without DM) treated with sirolimus- (n=104), paclitaxel- (n=303), zotarolimus- (n=391), or everolimus- (n=173) eluting stents. Volumetric data were standardized by length as volume index (VI). At postprocedure, lumen VI at the stented segment was significantly smaller in DM than in non-DM, whereas vessel VI was similar between the 2 groups. At follow-up, neointimal obstruction and maximum cross-sectional narrowing (neointimal area/stent area) were not significantly different between the 2 groups with no interaction for the DES type. Consequently, lumen VI was smaller in DM than in non-DM at follow-up. In the reference segments, residual plaque burden at postprocedure was significantly greater in DM than in non-DM, although change in lumen VI was similar between the 2 groups. The arterial responses at the reference segments also showed no interaction for the DES type.

CONCLUSIONS

DM and non-DM lesions showed similar vessel response in both in-stent and reference segments regardless of the DES type. In the DES era, the follow-up lumen in DM patients seems to be determined primarily by the smaller lumen at postprocedure rather than exaggerated neointima within the stent or plaque proliferation at the reference segments.

Outcomes with various drug eluting or bare metal stents in patients with diabetes mellitus: mixed treatment comparison analysis of 22,844 patient years of follow-up from randomised trials

OBJECTIVES

To evaluate the efficacy and safety of currently used drug eluting stents compared with each other and compared with bare metal stents in patients with diabetes.

DESIGN

Mixed treatment comparison meta-analysis.

DATA SOURCES AND STUDY SELECTION

PubMed, Embase, and CENTRAL were searched for randomised clinical trials, until April 2012, of four durable polymer drug eluting stents (sirolimus eluting stents, paclitaxel eluting stents, everolimus eluting stents, and zotarolimus eluting stents) compared with each other or with bare metal stents for the treatment of de novo coronary lesions and enrolling at least 50 patients with diabetes.

PRIMARY OUTCOMES

Efficacy (target vessel revascularisation) and safety (death, myocardial infarction, stent thrombosis).

RESULTS

From 42 trials with 22,844 patient years of follow-up, when compared with bare metal stents (reference rate ratio 1) all of the currently used drug eluting stents were associated with a significant reduction in target vessel revascularisation (37% to 69%), though the efficacy varied with the type of stent (everolimus eluting stents~sirolimus eluting stents>paclitaxel eluting stents~zotarolimus eluting stent>bare metal stents). There was about an 87% probability that everolimus eluting stents were the most efficacious compared with all others, though there were limited usable data for the zotarolimus eluting Resolute stent in patients with diabetes. Moreover, there was no increased risk of any safety outcome (including very late stent thrombosis) with any drug eluting stents compared with bare metal stents. There was about a 62% probability that the everolimus eluting stent was the safest stent for the outcome of "any" stent thrombosis.

CONCLUSIONS

Among patients with diabetes treated with coronary stents all currently available drug eluting stents were efficacious without compromising safety compared with bare metal stents. There were relative differences among the drug eluting stents, such that the everolimus eluting stent was the most efficacious and safe.

Comparison of everolimus- versus paclitaxel-eluting stents implanted in patients with diabetes mellitus as evaluated by three-dimensional intravascular ultrasound analysis

Previous reports have shown the advantage of paclitaxel compared to limus-derivative drugs for the treatment of diabetics. A total of 109 diabetics (115 lesions) treated with everolimus-eluting stents (EESs, n = 58) or paclitaxel-eluting stents (PESs, n = 55) undergoing 8 to 9 months of follow-up 3-dimensional intravascular ultrasound examinations were enrolled. In addition to the standard intravascular ultrasound parameters, the percentage of neointimal volume (neointimal volume/stent volume) and maximum percentage of cross-sectional narrowing (neointimal area/stent area) was calculated. EESs showed a lower percentage of neointimal volume (7.2 +/- 7.1% vs 11.7 +/- 11.0%; p = 0.01) and maximum percentage of cross-sectional narrowing (22.5 +/- 16.3% vs 29.4 +/- 19.2%; p = 0.04) than PESs. One case of severe narrowing (lesions with maximum percentage of cross-sectional narrowing >60%) in the EES group developed and 6 cases in the PESs group (p = 0.05). The EESs showed no serial changes for vessel or peri-stent plaque during the follow-up period, and PESs showed significant increases in vessel and peri-stent plaque. PESs showed significantly greater peri-stent plaque increase, with a tendency toward greater vessel enlargement than EESs. Late acquired incomplete stent apposition was observed in 2 PES cases. The major adverse cardiac event rate was comparable < or =2 years. In conclusion, EESs showed greater neointimal suppression without significant vessel expansion than PESs in diabetic patients. In this small cohort, no significant differences were observed in the major adverse cardiac event rate < or =2 years.

[Revascularization of coronary artery disease in diabetes mellitus]

Coronary artery disease in diabetes mellitus (DM) is still associated with a poor prognosis. Especially percutaneous coronary interventions (PCI) have a higher rate of complications and restenosis, so that surgical revascularization is usually favoured in DM. The development of drug-eluting stents has improved the results of PCI significantly, however, there are still not enough prospective data comparing them to bypass surgery. The present paper summarizes the current state of coronary revascularization.

Intravascular ultrasound assessment of expansion of the sirolimus-eluting (cypher select) and paclitaxel-eluting (Taxus Express-2) stent in patients with diabetes mellitus

Patients with diabetes have a higher risk for in-stent restenosis after coronary stent implantation. Drug-eluting stents (DES) are highly effective in reducing in-stent restenosis. Once neointimal hyperplasia is suppressed with DES, the impact of stent underexpansion becomes magnified. The aim of this study was to evaluate DES expansion in patients with diabetes. Ninety-five patients with diabetes were randomized to Cypher Select (n = 48) or Taxus Express-2 (n = 47) stent implantation. Intravascular ultrasound was performed after stent implantation. Stent expansion was defined as the ratio of measured to predicted minimum stent diameter. There was a trend for lower stent expansion in the Cypher Select stent group (0.74 +/- 0.08 vs 0.78 +/- 0.11 in the Taxus Express-2 stent group, p = 0.061). Cypher Select stents achieved a final minimal stent cross-sectional area of 5.5 +/- 1. 8 mm2, compared with 6.4 +/- 1.9 mm2 for Taxus Express-2 stents (p = 0.015). For stents with nominal diameters > or =2.75 mm (Cypher Select n = 40, Taxus Express-2 n = 38), 42.5% of the Cypher Select stents and 10.5% of the Taxus Express-2 stents did not achieve a final minimum stent area of 5 mm2 (p = 0.002). Insulin treatment (relative risk 0.31, 95% confidence interval 0.10 to 0.95, p = 0.041) and stent type (relative risk 0.15, 95% CI 0.04 to 0.53, p = 0.003) were independent predictors of not achieving a minimum stent area >5.0 mm2. In conclusion, an important percentage of DES in patients with diabetes fail to achieve the manufacturers' predicted final minimal stent diameter. Cypher Select stent and insulin treatment were independent predictors of not achieving a minimum stent area >5.0 mm2.

Volumetric intravascular ultrasound imaging to illustrate the extent of coronary plaque burden in type 2 diabetic patients

BACKGROUND

Although angiography is the gold standard for coronary imaging, its efficacy in outlining diffuse coronary atherosclerosis in diabetic patients remains questionable. We aimed to compare quantitative cineangiographic analysis (QCA) with three-dimensional intravascular ultrasound (IVUS) imaging in type 2 diabetic patients with coronary artery disease.

METHODS

IVUS runs of 104 significant coronary lesions in 88 diabetic patients were performed. Arterial remodeling index was calculated as vessel area at minimal lumen area divided by mean reference vessel area.

RESULTS

No difference between the two analysis modes was shown for lesion length and minimal lumen diameter, whereas a significant discrepancy between QCA and IVUS was found for diameter stenosis (10 +/- 9% vs. 41 +/- 8%; P<.001) and vessel diameter (3.01 +/- 0.66 vs. 4.53 +/- 0.70 mm; P<.001). A significant difference on arterial remodeling at lesion site was found between insulin-treated diabetic patients and non-insulin-treated diabetic patients (remodeling index: 0.98 +/- 0.16 vs. 1.07 +/- 0.21; P=.04).

CONCLUSIONS

Coronary angiographic diagnosis in diabetic patients may be distorted due to a large plaque burden over longer vessel segments and the resulting absence of plaque-free reference segments. This distortion was found to be more pronounced in QCA analysis requiring a reference diameter, whereas volumetric IVUS imaging illustrated coronary artery dimensions more accurately according to anatomic structures. Constrictive arterial remodeling was observed more frequently in type 2 diabetic patients treated with insulin.

Comparison of coronary restenosis rates in matched patients with versus without diabetes mellitus

Diabetes mellitus (DM) is an established risk factor for stent restenosis, in part as a result of the smaller vessel dimensions and longer lesions. This study compared the magnitude of acute lumen gain and late lumen loss after elective coronary stent implantation in patients with and without DM using a matched-pair analysis. A total of 133 patients with DM and 192 coronary lesions were included in this analysis. A group of 192 lesions in 182 patients without DM were matched in a pairwise fashion, stratifying for reference diameter, minimal luminal diameter, and lesion length. The binary restenosis rate at the 5-month follow-up angiography was 25% in the DM group and 14% in the non-DM group (p <0.01). Acute angiographic lumen gain (1.47 +/- 0.41 vs 1.56 +/- 0.38 mm, p = 0.03) and late lumen loss (0.64 +/- 0.42 vs 0.55 +/- 0.36 mm, p = 0.02) were significantly different between the DM and non-DM groups. In conclusion, suboptimal acute procedural results and an exaggerated neointimal proliferation contributed by about 50% to the lower net lumen gain in the DM group. Patients with DM had a significantly higher restenosis rate even when matched for preprocedural angiographic lesion dimensions. Mechanistically, inferior procedural results, as well as exaggerated neointimal proliferation, are, quantitatively, equally important in this process.

Outcomes with the polymer-based paclitaxel-eluting TAXUS stent in patients with diabetes mellitus

OBJECTIVES

We sought to determine the safety and efficacy of polymer-regulated site-specific delivery of paclitaxel in patients with diabetes mellitus undergoing stent implantation.

BACKGROUND

Percutaneous coronary intervention in patients with diabetes is associated with high rates of restenosis and repeat revascularization due to excessive neointimal proliferation, a process that may be blunted with the site-specific delivery of paclitaxel.

METHODS

In the TAXUS-IV trial, 1,314 patients were prospectively randomized to the slow rate-release polymer-based paclitaxel-eluting TAXUS stent or the bare-metal EXPRESS stent (Boston Scientific Corp., Natick, Massachusetts). Medically treated diabetes was present in 318 patients (24%), 105 of whom required insulin.

RESULTS

Among patients with diabetes, the TAXUS stent, compared to the bare-metal stent, reduced the rate of 9-month binary angiographic restenosis by 81% (6.4% vs. 34.5%, p < 0.0001), and reduced the 12-month rates of target lesion revascularization by 65% (7.4% vs. 20.9%, p = 0.0008), target vessel revascularization by 53% (11.3% vs. 24%, p < 0.004), and composite major adverse cardiac events by 44% (15.6% vs. 27.7%, p = 0.01). The one-year rates of cardiac death (1.9% vs. 2.5%), myocardial infarction (3.2% vs. 6.4%), and subacute thrombosis (0.6% vs. 1.2%) were comparable between the paclitaxel-eluting and control stents, respectively. In the insulin-requiring subgroup, the TAXUS stent reduced angiographic restenosis by 82% (7.7% vs. 42.9%, p = 0.0065), and reduced the one-year rate of target lesion revascularization by 68% (6.2% vs. 19.4%, p = 0.07), a relative reduction similar to patients without diabetes.

CONCLUSIONS

The site-specific delivery of paclitaxel after coronary stent implantation is highly effective in reducing clinical and angiographic restenosis in patients with diabetes mellitus.