In-stent restenosis: long-term outcome and predictors of subsequent target lesion revascularization after repeat balloon angioplasty

Value of the American College of Cardiology/American Heart Association angiographic classification of coronary lesion morphology in patients with in-stent restenosis. Insights from the Restenosis Intra-stent Balloon angioplasty versus elective Stenting (RIBS) randomized trial

BACKGROUND

The implications of the American College of Cardiology/American Heart Association (ACC/AHA) lesion classification in patients with in-stent restenosis (ISR) are unknown.

METHODS

Four hundred fifty patients included in the RIBS randomized study were analyzed. A centralized core laboratory assessed ISR classifications including ACC/AHA, the classification of Mehran et al (Circulation 1999;100:1872-8), diffuse/focal, and a new quantitative ISR index (lesion length/stent length). Logistic regression models were constructed for prespecified outcome measures including (1) unsatisfactory acute results and (2) recurrent restenosis rate.

RESULTS

Complex (B2/C) lesions (78%) more frequently obtained unsatisfactory acute results (20% vs 8%, P = .007), smaller minimal lumen diameter after the procedure (2.45 +/- 0.5 vs 2.73 +/- 0.5 mm, P = .001) and at follow-up (1.48 +/- 0.8 vs 1.94 +/- 0.8 mm, P = .0001), and had a higher restenosis rate (43 vs 24%, P = .001) than simple (A/B1) lesions. On logistic regression analysis, all classification schemes were useful to predict unsatisfactory initial results (area under the curve: 0.63, 0.61, 0.59, and 0.62) and recurrent restenosis (area under the curve: 0.60, 0.64, 0.61, and 0.63). The predictive ability of these schemes persisted despite adjustment for potential confounders. Although the ACC/AHA classification was a better predictor of acute results, the classification of Mehran was superior to predict restenosis.

CONCLUSIONS

The ACC/AHA classification provides a useful tool to determine acute procedural results and the long-term angiographic outcome of patients with ISR.

Myocardial Infarction as a Presentation of Clinical In-Stent Restenosis

BACKGROUND

In-stent restenosis is considered to be a gradual and progressive condition and there is scant data on myocardial infarction (MI) as a clinical presentation.

METHODS AND RESULTS

Of 2,462 consecutive patients who underwent percutaneous coronary intervention between June 2001 and December 2002, clinical in-stent restenosis occurred in 212 (8.6%), who were classified into 3 groups: ST elevation MI (STEMI), non-ST elevation MI (NSTEMI) and non-MI. Of the 212 patients presenting with clinical in-stent restenosis, 22 (10.4%) had MI (creatine kinase (CK)>or=2xbaseline with elevated CKMB). The remaining 190 (89.6%) patients had stable angina or evidence of ischemia by stress test without elevation of cardiac enzymes. Median interval between previous intervention and presentation for clinical in-stent restenosis was shorter for patients with MI than for non-MI patients (STEMI, 90 days; NSTEMI, 79 days; non-MI, 125 days; p=0.07). Diffuse in-stent restenosis was more frequent in MI patients than in non-MI patients (72.7% vs 56.3%; p<0.005). Renal failure was more prevalent in patients with MI than in those without MI (31.8% vs 6.3%, p=0.001). Compared with the non-MI group, patients with MI were more likely to have acute coronary syndromes at the time of index procedure (81.8% vs 56.8%, p=0.02).

CONCLUSION

Clinical in-stent restenosis can frequently present as MI and such patients are more likely to have an aggressive angiographic pattern of restenosis. Renal failure and acute coronary syndromes at the initial procedure are associated with MI.

Long-term results (three to five years) of the Restenosis Intrastent: Balloon angioplasty versus elective Stenting (RIBS) randomized study

OBJECTIVES

We sought to analyze the very late outcomes of patients treated for in-stent restenosis (ISR) according to treatment allocation and 10 prespecified variables.

BACKGROUND

Long-term results (>2 years) of patients with ISR undergoing repeat coronary interventions are not well established.

METHODS

The Restenosis Intrastent: Balloon angioplasty versus elective Stenting (RIBS) randomized study compared these two strategies in 450 patients with ISR. A detailed systematic protocol was used for late clinical follow-up.

RESULTS

At one-year follow-up (100% of patients), the event-free survival was similar in the two groups (77% stent implantation [ST] arm, 71% balloon angioplasty [BA] arm, log-rank p = 0.19). Additional long-term clinical follow-up (median 4.3 years, range 3 to 5 years) was obtained in 98.6% of patients. During this time 22 additional patients died (9 ST arm, 13 BA arm), 7 suffered a myocardial infarction (3 ST arm, 4 BA arm), 23 required coronary surgery (11 ST arm, 12 BA arm), and 9 underwent repeat coronary interventions (4 ST arm, 5 BA arm) (nonexclusive events). At four years the event-free survival was 69% in the ST arm and 64% in the BA arm (log-rank p = 0.21). Among the 10 prespecified variables, vessel size > or = 3 mm had a major influence on the clinical outcome at four years, with better results in the ST group (hazard ratio 0.51, 95% confidence interval 0.3 to 0.89, p = 0.016).

CONCLUSIONS

Patients with ISR undergoing repeat interventions have a significant event rate at late follow-up. Continued medical surveillance should be continued after one year. Patients with large vessels have a better outcome after repeat stenting.

The impact of metallic allergy on stent implantation

BACKGROUND

Relation between metallic allergy and in-stent restenosis (ISR) has been inconclusive. We hypothesized that mechanism of restenosis is different between initial stent implantation and dilatation for ISR. Thus, we studied metallic allergy and restenosis in these two different situations separately.

METHODS AND RESULTS

We performed follow-up angiography and patch test for metallic allergy in a total of 174 stented consecutive patients, 109 patients (63%) for restudy of initial stent implantation and 65 patients (37%) for restudy of treatment following ISR. The positive rate of patch test in initial stent implantation was not significantly different between with or without restenosis (10% vs. 9%; p=ns). Whereas, following dilatation of ISR, the incidence of positive patch test was significantly higher in patients with recurrence of restenosis than those without the recurrence (39% vs. 12%; p=0.02). Multivariate analysis revealed that the positive patch test (Odd Ratio 4.39, p=0.02) and diffuse typed ISR (Odd Ratio 3.68, p=0.03) were significant predictors of recurrent restenosis.

CONCLUSIONS

Metal allergy does not have any correlation with the restenosis after initial stent implantation. However, metal allergy is frequently observed in patients with recurrence of ISR. Metal allergy may contribute to a mechanism in the repeat recurrence of ISR, but not to restenosis after initial stent implantation.

Serial intravascular ultrasound comparison of the extent and distribution of intimal hyperplasia six months after stent implantation for de novo versus in-stent restenosis lesions

The aim of this study was to compare intimal hyperplasia (IH) growth at 6 months in patients with de novo lesions treated with stents versus IH regrowth in patients with treated in-stent restenosis. Intravascular ultrasound was performed after intervention and at the 6-month follow-up visit as part of a standardized protocol across several clinical trials. At 6 months, the lumen was larger in the de novo group (mean lumen cross-sectional area [CSA] 6.31 +/- 2.2 vs 4.48 +/- 1.9 mm(2), p = 0.0001; minimum lumen CSA 4.2 +/- 1.8 vs 2.59 +/- 1.5 mm(2), p = 0.0001). However, the total increase in the mean IH CSA volume was the similar in the de novo and ISR groups (2.89 +/- 1.6 vs 2.64 +/- 1.94 mm(2), respectively; p = 0.11). We found that IH regrowth in restented in-stent restenosis lesions was similar to that in de novo stent implantation and that the final lumen CSA was an important component of in-stent restenosis recurrence.

Repeat stenting for the prevention of the early lumen loss phenomenon in patients with in-stent restenosis. Angiographic and intravascular ultrasound findings of a randomized study

BACKGROUND

Early lumen loss (ELL) may be detected in patients undergoing coronary interventions for in-stent restenosis. This phenomenon may contribute to recurrences. This prospective, randomized study was designed to determine if repeat stent implantation may prevent ELL in patients with in-stent restenosis.

METHODS

Forty patients were randomized: 20 were allocated to elective stent implantation and 20 to conventional balloon angioplasty. Quantitative coronary angiography and intravascular ultrasound (IVUS) volumetric studies were systematically performed (1) before the procedure, (2) immediately after intervention, and (3) 30 to 60 minutes later.

RESULTS

Baseline characteristics were similar in both groups. After the delay time interval (46 +/- 8 minutes), quantitative coronary angiography revealed a significant reduction in minimal lumen diameter (2.2 +/- 0.5 mm vs 1.7 +/- 0.5 mm, P < .001) in the balloon angioplasty arm. Likewise, in this group, IVUS demonstrated a reduction in mean lumen area (7.1 +/- 2 mm2 vs 6.2 +/- 2 mm2 , P < .001) and lumen volume (144 +/- 59 mm3 vs 126 +/- 54 mm3 , P < .001). In 4 of these patients, ELL was severe enough to require further intervention. In the stent arm, however, angiographic data and IVUS mean lumen area (7.7 +/- 3 mm2 vs 7.7 +/- 3 mm2) and lumen volume (161 +/- 72 mm3 vs 160 +/- 69 mm3) remained unchanged after the delay time interval. On multivariate analysis, stent implantation was an independent predictor of the absence of ELL by quantitative coronary angiography and by IVUS. In addition, patients with a larger ELL on IVUS had a lower event-free survival at 1 year (40% vs 79%, log rank P = .003).

CONCLUSIONS

This randomized study demonstrates that (1) ELL is frequently detected after treatment of in-stent restenosis with balloon angioplasty, that (2) ELL influences the long-term clinical outcome of these patients, and that (3) repeat stent implantation prevents ELL.

Cutting balloon versus conventional balloon angioplasty for the treatment of in-stent restenosis: results of the restenosis cutting balloon evaluation trial (RESCUT)

OBJECTIVES

The aim of this trial was to compare cutting balloon angioplasty (CBA) with conventional balloon angioplasty (i.e., percutaneous transluminal coronary angioplasty [PTCA]) for the treatment of patients with coronary in-stent restenosis (ISR).

BACKGROUND

Retrospective studies suggest CBA might be superior to conventional PTCA in the treatment of ISR.

METHODS

The Restenosis Cutting Balloon Evaluation Trial (RESCUT) is a multicenter, randomized, prospective European trial including 428 patients with all types of ISR (e.g., focal, multifocal, diffuse, proliferative).

RESULTS

In both groups, the majority of ISR lesions were shorter than 20 mm. The length of restenotic stents was similar (CBA: 18.6 +/- 9.7 mm; PTCA: 18.3 +/- 8.7 mm). The number of balloons used to treat ISR was lower in the CBA group: only one balloon was used in 82.3% of CBA cases, compared with 75% of PTCA procedures (p = 0.03). Balloon slippage was less frequent in the CBA group (CBA 6.5%, PTCA 25%; p < 0.01). There was a trend toward a lower need for additional stenting in the CBA group (CBA 3.9%, PTCA 8.0%; p = 0.07). At seven-month angiographic follow-up, the binary restenosis rate was not different between the groups (CBA 29.8%, PTCA 31.4%; p = 0.82), with a similar pattern of recurrent restenosis. Clinical events at seven months were also similar.

CONCLUSIONS

Cutting balloon angioplasty did not reduce recurrent ISR and major adverse cardiac events, as compared with conventional PTCA. However, CBA was associated with some procedural advantages, such as use of fewer balloons, less requirement for additional stenting, and a lower incidence of balloon slippage.

Favorable effect of ?-radiation for in-stent restenosis: Effect of diabetes on angiographic and clinical outcomes

The purpose of this study was to examine the effect of vascular brachytherapy with gamma-radiation (gamma-RT) in patients with diabetes mellitus (DM) with coronary in-stent restenosis (ISR). In the Washington Radiation for In-Stent Restenosis (WRIST) trial, 130 patients with ISR were treated with (192)Ir or placebo. Of the patients enrolled, 44 (34%) had DM (18 of them treated with gamma-RT and 26 with placebo). Gamma-radiation therapy of ISR in diabetics resulted in similar procedural success and in-hospital outcome compared to nondiabetics. At 6-month follow-up, both DM and non-DM patients treated with gamma-RT had significantly lower target lesion revascularization (TLR), target vessel revascularization, and major adverse cardiac event rates compared to placebo. DM remains a powerful predictor of TLR and major adverse cardiac events even after treatment of ISR with gamma-RT.

Percutaneous treatment of focal vs. diffuse in-stent restenosis: A prospective randomized comparison of conventional therapies

Few randomized studies compare outcomes for focal vs. diffuse in-stent restenosis (ISR) using conventional treatments. The purpose of this study was to compare the rates of major adverse cardiac events (MACEs) for focal vs. diffuse ISR using conventional techniques. One hundred thirteen patients with ISR were prospectively classified as focal (< 10 mm) or diffuse (> 10 mm). Focal ISR was randomized to balloon angioplasty (n = 29) or restenting (n = 29) and diffuse ISR randomized to rotational atherectomy (n = 30) or restenting (n = 25). At 9 months, patients with focal ISR had higher survival free of MACEs than patients with diffuse ISR (86% vs. 63%; P < 0.005), with no difference between techniques. Only the presence of diffuse ISR was an independent predictor of MACE at 9 months. Thus, focal ISR has a low rate of MACE compared to diffuse ISR, which carries a high event rate regardless of treatment employed.

Gamma radiation for in-stent restenosis: effect of lesion length on angiographic and clinical outcomes

The relation between lesion length and effectiveness of gamma radiation treatment (gamma-RT) has not been well described. We evaluated the acute and long-term outcome according to baseline lesion length in 130 patients treated with (192)Ir in the Washington Radiation for In-Stent Restenosis Trial; 44 (35.5%) had baseline short in-stent restenosis (ISR) lesions (length < 15 mm) and 80 (64.5%) long ISR lesions (length > or = 15 mm). At 6-month follow-up after gamma-RT, the short ISR group had larger lumen dimensions and lower late loss than the long ISR group. Restenosis rate was significantly higher in patients with long ISR for both the placebo (74% vs. 39%; P = 0.01) and the gamma-RT arm (31% vs. 5.3%; P = 0.04). gamma-RT significantly improved the angiographic outcome in the short-lesion groups but had the more pronounced effect on the reduction of clinical events after treatment of long ISR group. Lesion length remains a powerful predictor of recurrent ISR and clinical events after treatment of ISR even with gamma-RT.

Usefulness of the angiographic pattern of in-stent restenosis in predicting the success of gamma vascular brachytherapy

The prognostic role of the angiographic pattern of in-stent restenosis after gamma vascular brachytherapy was assessed from a pooled data set of 4 clinical trials comprising 295 irradiated patients with matched baseline and follow-up angiograms. The binary angiographic restenosis rate increased with worsening in-stent restenosis patterns; however, target lesion revascularization and major adverse cardiac event rates increased for focal, diffuse, and proliferative patterns of in-stent restenosis but not for total occlusions.

A randomized comparison of repeat stenting with balloon angioplasty in patients with in-stent restenosis

OBJECTIVES

This randomized trial compared repeat stenting with balloon angioplasty (BA) in patients with in-stent restenosis (ISR).

BACKGROUND

Stent restenosis constitutes a therapeutic challenge. Repeat coronary interventions are currently used in this setting, but the recurrence risk remains high.

METHODS

We randomly assigned 450 patients with ISR to elective stent implantation (224 patients) or conventional BA (226 patients). Primary end point was recurrent restenosis rate at six months. Secondary end points included minimal lumen diameter (MLD), prespecified subgroup analyses, and a composite of major adverse events.

RESULTS

Procedural success was similar in both groups, but in-hospital complications were more frequent in the balloon group. After the procedure MLD was larger in the stent group (2.77 +/- 0.4 vs. 2.25 +/- 0.5 mm, p < 0.001). At follow-up, MLD was larger after stenting when the in-lesion site was considered (1.69 +/- 0.8 vs. 1.54 +/- 0.7 mm, p = 0.046). However, the binary restenosis rate (38% stent group, 39% balloon group) was similar with the two strategies. One-year event-free survival (follow-up 100%) was also similar in both groups (77% stent vs. 71% balloon, p = 0.19). Nevertheless, in the prespecified subgroup of patients with large vessels (> or =3 mm) the restenosis rate (27% vs. 49%, p = 0.007) and the event-free survival (84% vs. 62%, p = 0.002) were better after repeat stenting.

CONCLUSIONS

In patients with ISR, repeat coronary stenting provided better initial angiographic results but failed to improve restenosis rate and clinical outcome when compared with BA. However, in patients with large vessels coronary stenting improved the long-term clinical and angiographic outcome.

Stent-induced restenosis in the swine coronary artery is inhibited by a platelet-derived growth factor receptor tyrosine kinase inhibitor, TKI963

Activities of vascular smooth muscle cells (SMCs) such as proliferation, migration, and matrix production contribute to restenosis following clinical interventions of angioplasty and stent placement. Because activation of platelet-derived growth factor (PDGF)-receptor tyrosine kinase (PDGFr-TK) influences these processes and promotes restenosis, TKI963, an inhibitor of the PDGFr-TK was discovered, and its efficacy was evaluated in blocking stent-induced restenosis as analyzed by intravascular ultrasound (IVUS). TKI963, a low-molecular-weight compound, inhibited the cell-free PDGFbetar-TK with a K(i) value of 56 +/- 14 nM. TKI963 also inhibited PDGF-dependent events in human aortic SMCs (e.g., in situ PDGFr autophosphorylation, mitogenesis, chemotaxis, and collagen production with median inhibitory concentration values of approximately 300 nM) without affecting the activity of a series of membrane receptor tyrosine kinases and intracellular serine/threonine kinases. In vivo, stent-induced restenosis in the swine coronary artery was reduced by oral administration of TKI963 (1.25, 2.5, and 5 mg/kg BID, for 28 days). Late lumen cross-sectional area (CSA) loss, plaque CSA growth, and plaque volume in the stent determined by IVUS were dose-relatedly decreased (33-62% at 1.25 mg/kg BID to 66-92% at 5 mg/kg BID, depending on the parameter) compared with controls. TKI963 treatment of </=1 week following stent placement had no effect on the prevention of restenosis. TKI963, a selective, orally bioavailable inhibitor of the PDGFr-TK, dose-relatedly reduced stent-induced restenosis and did so by inhibiting PDGF-dependent activities that occur as late events following stent placement.

Intracoronary radiation therapy improves the clinical and angiographic outcomes of diffuse in-stent restenotic lesions: results of the Washington Radiation for In-Stent Restenosis Trial for Long Lesions (Long WRIST) Studies

BACKGROUND

The Washington Radiation for In-Stent Restenosis Trial for long lesions (Long WRIST) was designed to determine the safety and efficacy of vascular brachytherapy for the treatment of diffuse in-stent restenosis.

METHODS AND RESULTS

A total of 120 patients with diffuse in-stent restenosis in native coronary arteries (lesion length, 36 to 80 mm) were randomized for either radiation with 192Ir with 15 Gy at 2 mm from the source axis or placebo. After enrollment, 120 additional patients with the same inclusion criteria were treated with 192Ir with 18 Gy and included in the Long WRIST High Dose registry. Antiplatelet therapy was initially prescribed for 1 month and was extended to 6 months in the last 60 patients of the Long WRIST High Dose registry. At 6 months, the binary angiographic restenosis rate was 73%, 45%, and 38% in the placebo, 15 Gy, and 18 Gy radiated groups, respectively (P<0.05). At 1 year, the primary clinical end point of major cardiac events was 63% in the placebo group and 42% in the radiated group with 15 Gy (P<0.05). The major cardiac event rate was further reduced with 18 Gy (22%; P<0.05 versus 15 Gy). Late thrombosis was 12%, 15%, and 9% in the placebo group, 15 Gy group with 1 month of antiplatelet therapy, and 18 Gy group with 6 months of antiplatelet therapy, respectively.

CONCLUSIONS

Vascular brachytherapy with 192Ir is safe and reduces the rate of recurrent restenosis in diffuse in-stent restenosis. The efficacy of vascular brachytherapy on angiographic and clinical outcomes is enhanced with a radiation dose of 18 Gy and prolonged antiplatelet therapy.

Relationship between neointimal regrowth and mechanism of acute lumen gain during the treatment of in-stent restenosis with or without supplementary intravascular radiation

We investigated whether neointimal regrowth is related to the mechanism of acute lumen gain during the treatment of in-stent restenosis (ISR) lesions both with and without adjunct intravascular brachytherapy. From the WRIST (Washington Radiation for In-Stent Restenosis Trial) cohort, 54 ISR patients ((192)Ir, 29; placebo, 25) were treated with nonrepeat stenting percutaneous interventions (excimer laser, rotational atherectomy, and/or balloon angioplasty) prior to (192)Ir or placebo therapy. Using Simpson's method, serial volumetric intravascular ultrasound (IVUS) analyses (pre- and posttreatment and 6-month follow-up) were analyzed to obtain stent, lumen, and intimal hyperplasia (IH) volumes that were then adjusted for stent length to create stent, lumen, and IH volume indexes. In the placebo group, the acute reduction of neointima (1.6 +/- 1.4 mm(3)/mm) was counteracted by intimal regrowth (2.1 +/- 1.7 mm(3)/mm). The amount of intimal regrowth correlated directly with the intimal reduction due to the intervention (r = 0.76; P < 0.001), but not with the amount of additional stent expansion. In the (192)Ir-treated group, intimal regrowth was significantly less than in the placebo group (-0.3 +/- 0.1 vs. 2.1 +/- 1.7 mm(3)/mm; P < 0.001) despite a similar initial intimal reduction (1.3 +/- 0.9 vs. 1.6 +/- 1.4 mm(3)/mm; P = NS). No correlation was found between intimal reduction at the time of the procedure and intimal regrowth in the (192)Ir group. In this study, neointimal regrowth following treatment of ISR lesions correlates directly with the extent of acute intimal volume reduction, but not with the extent of additional stent expansion. This relation is not seen in ISR segments treated with radiation, where intimal regrowth is substantially inhibited.

The initial course of in-stent restenosis influences the response to vascular brachytherapy

BACKGROUND

Vascular brachytherapy (VBT) reduces the rate of recurrence of in-stent restenosis (ISR) by inhibiting intimal proliferation. However, the rate of cell proliferation, reflected by the speed of ISR development, is variable in ISR lesions and might influence the responsiveness of ISR to radiation. The aim of this study was to determine the influence of the initial ISR course on the clinical outcome of patients undergoing VBT.

METHODS

In 1165 patients treated for ISR with VBT in the WRIST studies, we determined the time for ISR (time between initial stent implantation and restenosis), the time for VBT treatment (time between stent implantation and VBT), and previous ISR treatment with conventional strategies. Target lesion revascularization (TLR) at 6 months was available in all patients.

RESULTS

Previous ISR treatment did not influence the result of VBT (TLR was 17% vs. 16% without previous angioplasty). Time to ISR influences the outcome of patients undergoing VBT; TLR decreased when ISR occurred later. TLR was 18.2%, 16.7%, and 11.1% when time to ISR was <90, 90-2700, and >270 days, respectively, P=.03. Early ISR (time for ISR <90 days) is a factor for radiation failure (OR=2.1, P<.05). In patients with early ISR, TLR is lower when VBT is delayed; TLR was 11% if performed 90 days after stent implantation as compared to 22% if VBT is performed early (<90 days), P<.05.

CONCLUSION

The course of ISR development affects the long-term efficacy of VBT. Early restenosis remains a factor of treatment failure in the VBT era. Delaying VBT beyond 90 days after stent implantation reduces the rate of subsequent revascularization in these patients.

Acute coronary syndrome is a common clinical presentation of in-stent restenosis

Coronary stents have been the major advancement in percutaneous coronary intervention in the last decade and are used in 60% to 80% of patients. However, in-stent restenosis continues to be a problem, occurring in 20% to 30% of cases. The clinical presentation of patients who develop restenosis after stenting has not been well characterized. In this study we compared the clinical presentation of in-stent restenosis with that of restenosis without stenting. Of 739 patients who underwent percutaneous coronary intervention and had repeat catheterization between October 1, 1997, and June 30, 2000, 262 consecutive patients with recurrent ischemia and restenosis were identified: 191 patients with (group A) and 71 without (Group B) stenting. Patients who underwent interventions in bypass grafts and those who developed early acute stent thrombosis were excluded from the study. Recurrent clinical ischemia occurred at a mean of 5.5 months in group A and 6.5 months in group B (p = 0.24). Rest angina (Braunwald class II and III) was more frequent in group A (48% vs 32%, p = 0.032). Acute coronary syndromes, the combination of rest angina, and acute myocardial infarction were also more frequent in group A (68% vs 46%, p = 0.03). Patients in group A were more likely to have angiographically visible thrombus than those in group B (9% vs 0%, p = 0.02). Thus, acute coronary syndromes are a common clinical presentation of restenosis among patients whose follow-up angiogram is obtained for clinical reasons, and occur more frequently in patients with in-stent restenosis than in those with restenosis without stenting.

Rotational atherectomy does not reduce recurrent in-stent restenosis: results of the angioplasty versus rotational atherectomy for treatment of diffuse in-stent restenosis trial (ARTIST)

BACKGROUND

Aim of this trial was to compare rotational atherectomy followed by balloon angioplasty (rotablation [ROTA] group) with balloon angioplasty (percutaneous transluminal coronary angioplasty [PTCA] group) alone in patients with diffuse in-stent restenosis.

METHODS AND RESULTS

The ARTIST study is a multicenter, randomized, prospective European trial with 298 patients with in-stent restenosis>70% (mean lesion length, 14 +/- 8 mm) in stents, implanted in coronary arteries for >/= 3 months. In the PTCA group, angioplasty was performed at the discretion of the local investigator, and rotablation was performed by using a stepped-burr approach followed by adjunctive PTCA with low (</= 6 atm) inflation pressure. Intravascular ultrasound during the intervention and at follow-up was used in a substudy in 86 patients (45 PTCA, 41 ROTA). Angiography demonstrated no difference regarding the short-term outcome, with equivalent procedural success rates defined as remaining stenosis <30% (89% PTCA, 88% ROTA). However, the results showed that, in the long term, PTCA was a significantly better strategy than ROTA. Mean net gain in minimal lumen diameter was 0.67 mm and 0.45 mm for PTCA and ROTA, respectively (P=0.0019). Mean gain in diameter stenosis was 25% and 17% (P=0.002), resulting in restenosis (>/= 50%) rates of 51% (PTCA) and 65% (ROTA) (P=0.039). By intravascular ultrasound, the major difference was the missing stent over-expansion during PTCA after ROTA. Six-month event-free survival was significantly higher after PTCA (91.3%) compared with ROTA (79.6%, P=0.0052).

CONCLUSIONS

In terms of the primary objective of the study, PTCA produced a significantly better long-term outcome than ROTA followed by adjunctive low-pressure PTCA.

Repeated intracoronary beta radiation for recurrent in-stent restenosis

More than 70% of percutaneous coronary interventions are followed by a stent implantation. In-stent restenosis still occurs in 20-30% of patients and remains a therapeutic challenge. At present only vascular brachytherapy has been shown to be an effective treatment option. We report here one case of recurrent in-stent restenosis after vascular brachytherapy that was successfully treated by a second beta radiation treatment.

Standalone cutting balloon angioplasty for the treatment of stent-related restenosis: acute results and 3- to 6-month angiographic recurrent restenosis rates

Despite excellent acute reperfusion results, 20%-30% of patients who undergo coronary stent implantation will develop angiographic restenosis and may require same additional treatments. Cutting Balloon angioplasty (CBA) causes less histological damage outside of the incised area than a regular balloon. However, regular plain old balloon angioplasty is sometimes required before CBA, as is adjunctive stenting and adjunctive angioplasty. These adjunctive strategies may negate the advantages of CBA. There is little data available on CBA as a standalone therapy for stent-related restenosis (SRS). The aim of this study was to evaluate the acute and 3- to 6-month angiographic recurrent restenosis rates following standalone CBA in a patient population treated for SRS and in whom optimal acute results were obtained. In this study, 40 patients with SRS (54 lesions) underwent standalone CBA with optimal acute results. For all lesions, coronary angiography was conducted before and after a standalone CBA procedure for SRS and systematically during 3-6 months to assess recurrent angiographic restenosis rates in the study population. In the study lesions, SRS was either diffuse disease (> 15 mm; 52%) or focal type (48%). Cutting Balloon diameter was 3.20 +/- 0.44 mm and maximal inflation pressure 8.7 +/- 1.2 atm. Ratio of Cutting Balloon diameter to restenotic stent diameter was 0.996 +/- 0.487. Multiple inflations (6 +/- 3 times) were performed. Number of used Cutting Balloon was 1.02 +/- 0.14. Complications were as follows; one non-Q-wave MI (1.9%); 0 death (0%), and 17 repeat target lesion revascularizations (TLRs; 32%). Follow-up coronary angiography (CAG) was not attained for one patient. The angiographic recurrent restenosis rate was 34%, with a higher rate observed when the SRS was diffuse type, 50% vs. 16% for focal-type SRS (P < 0.01). The recurrent restenosis rate for smaller vessels (vessel diameter < or = 3.0 mm) was the same as for larger ones. At follow-up CAG, diffuse-type recurrent restenosis (56%) presented nearly as frequently as that presenting in the original SRS lesions (52%). But four diffuse-type SRS (29%) changed into focal-type recurrent stenosis. In this study, standalone CBA for SRS with optimal acute results was associated with an angiographic restenosis rate of 34%. Diffuse-type disease had a higher recurrent restenosis rate. When CBA achieves acute optimal results, adjunctive stenting or adjunctive PTCA are not always necessary, particularly when the SRS is focal. As a result of CBA, some diffuse-type SRS may change into focal-type recurrent stenosis by the time of the next intervention.

Intravascular ultrasound analysis of beta radiation therapy for diffuse in-stent restenosis to inhibit intimal hyperplasia

We evaluated the efficacy of beta-radiation therapy ((188)Re-MAG(3)) to inhibit intimal hyperplasia (IH) in diffuse in-stent restenosis by intravascular ultrasound (IVUS) analysis in 50 patients. Nine patients who did not agree with radiation therapy, and therefore underwent rotational atherectomy and balloon angioplasty for diffuse in-stent restenosis in the same study period, were selected for control groups. Serial IVUS comparisons were available in 44 of 50 patients with radiation therapy and 7 of 9 control patients. At 6-month follow-up, there was less significant increase of IH area in patients with radiation therapy than in control patients (Delta IH area = 0.1 +/- 0.8 mm(2) vs. 2.6 +/- 1.8 mm(2), P > 0.001 in mean values, and 0.6 +/- 1.4 mm(2) vs. 2.9 +/- 2.1 mm(2), P = 0.026 in values of follow-up lesion site, respectively). In conclusion, beta-radiation therapy might be an effective treatment modality to inhibit intimal hyperplasia in patients with diffuse in-stent restenosis.

Serial intravascular ultrasound assessment of the efficacy of intracoronary gamma-radiation therapy for preventing recurrence in very long, diffuse, in-stent restenosis lesions

BACKGROUND

The efficacy of coronary gamma-irradiation in preventing recurrent in-stent restenosis (ISR) is well established. However, brachytherapy may be less effective in very long, diffuse ISR lesions.

METHODS AND RESULTS

We used serial intravascular ultrasound (IVUS) to study patients with long, diffuse ISR lesions (length, 36 to 80 mm) who were enrolled in (1) Long WRIST (Washington Radiation In-Stent Restenosis Trial), a double-blind, placebo-controlled trial of intracoronary gamma-irradiation (15 Gy at 2 mm from the source) and (2) high-dose (HD) Long WRIST, a registry that used a dose prescription of 18 Gy at 2 mm from the source. IVUS was performed using automated pullback (0.5 mm/s). Stent, lumen, and intimal hyperplasia were measured at 2-mm intervals. Complete postintervention and follow-up IVUS imaging was available in 30 irradiated and 34 placebo patients from Long WRIST and in 25 patients from HD Long WRIST. Stent length was longer in HD Long WRIST than in placebo or treated patients in Long WRIST (P=0.0064 and P=0.0125, respectively). Otherwise, baseline measurements were similar. At follow-up, the minimum lumen area was largest in the HD Long WRIST patients (4.0+/-1.4 mm(2)); areas were 2.9+/-1.0 mm(2) in irradiated patients in Long WRIST and 1.9+/-1.1 mm(2) in placebo patients in Long WRIST (P<0.005 for all comparisons).

CONCLUSIONS

- Serial IVUS analysis shows that gamma-irradiation reduces recurrent in-stent neointimal hyperplasia in long, diffuse ISR lesions; however, it is even more effective when given at a higher dose.

Usefulness of intracoronary brachytherapy for in-stent restenosis with a 188Re liquid-filled balloon

The objective of this randomized pilot trial with 21 patients was to evaluate the effectiveness of a rhenium-188 liquid-filled balloon system to prevent recurrent restenosis after percutaneous transluminal coronary angioplasty for in-stent restenosis. A significant benefit from brachytherapy was seen at 6-month repeat angiography, as well as during the clinical follow-up of 12 months.

Serial intravascular ultrasound analysis of the impact of lesion length on the efficacy of intracoronary gamma-irradiation for preventing recurrent in-stent restenosis

BACKGROUND

The relation between lesion length and effectiveness of brachytherapy is not well studied.

METHODS AND RESULTS

We compared serial (postintervention and follow-up) intravascular ultrasound findings in 66 patients with native coronary artery in-stent restenosis (ISR) who were treated with (192)Ir (15 Gy delivered 2 mm away from the radiation source). Patients were enrolled in the Washington Radiation for In-Stent Restenosis Trial (WRIST; ISR length, 10 to 47 mm; n=36) or Long WRIST (ISR length, 36 to 80 mm; n=30). External elastic membrane, stent, lumen, and intimal hyperplasia (IH; stent minus lumen) areas and source-to-target (intravascular ultrasound catheter to external elastic membrane) distances were measured. Postintervention stent areas were larger in WRIST and smaller in Long WRIST patients (P:<0.0001). At follow-up, maximum IH area significantly increased in both WRIST and Long WRIST patients (P:<0.0001 for both), but this increase was greater in Long WRIST patients (P:=0.0006). Similarly, minimum lumen cross-sectional area significantly decreased in both WRIST and Long WRIST patients (P:<0.05 and P:<0.0001, respectively), but this decrease was more pronounced in Long WRIST patients (P:=0.0567). The maximum source-to-target distance was longer in Long WRIST than in WRIST, and it correlated directly with ISR length (r=0.547, P:<0.0001). Overall, the change in minimum lumen area and the change in maximum IH area correlated with the maximum source-to-target distance (r=0.352, P:=0.0038 and r=0.523, P:<0.0001 for WRIST and Long WRIST, respectively). The variability (maximum/minimum) in IH area at follow-up also correlated with the maximum source-to-target distance (r=0.378, P:<0.0001).

CONCLUSIONS

Brachytherapy may be less effective in longer ISR lesions because of the greater variability and longer source-to-target distances in diffuse ISR.