Usefulness of gamma intracoronary radiation for totally occluded in-stent restenotic coronary narrowing.
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Biomedical subjects
Ron Waksman
Publications and source records attributed to Ron Waksman.
The outcome of percutaneous coronary intervention in patients with in-stent restenosis who failed intracoronary radiation therapy.
OBJECTIVES: This study reports the outcome of patients who failed intracoronary radiation therapy (IRT) for the treatment of in-stent restenosis (ISR). BACKGROUND: Intracoronary radiation therapy has demonstrated a reduction in the recurrence rate of restenosis for patients with ISR. However, 10% to 30% of these patients require repeat intervention to the irradiated site. METHODS: Of 961 patients who were assigned to gamma or beta radiation for the treatment of diffuse ISR, we evaluated the outcome of 282 (29%) consecutive patients who failed IRT and compared them with the 679 (71%) patients who had successful IRT. For patients who failed radiation, the mean time to the first target vessel revascularization (TVR) was 173 +/- 127 days after the index procedure and the total duration of follow-up was 494 +/- 304 days. RESULTS: Patients who failed IRT were younger (60 +/- 10 vs. 63 +/- 11 years, p = 0.002) and had a higher incidence of restenting (51% vs. 41%, p = 0.003). The majority (55%) of the restenotic lesions after IRT failure were focal (< or =10 mm), with a mean lesion length of 11.9 +/- 1.9 mm. Of the 257 patients who had subsequent TVR after failed IRT, 68 (26%) underwent coronary artery bypass grafting and 189 (74%) underwent percutaneous coronary intervention using balloon in 61%, restenting in 26%, atheroablation in 11%, and the cutting balloon in 2% of cases. At six months, 6% of patients died, 1% had Q-wave MI, 17% had repeat TVR, and the overall rate of major adverse cardiac events was 21%. CONCLUSIONS: The predominant angiographic pattern of lesions in patients who failed IRT is focal restenosis, with these lesions responding well to conventional revascularization methods.
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Thrombolytic therapy in patients with submassive pulmonary embolism.
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Drug Therapy, Combination↗
Comparison of intracoronary gamma radiation for in-stent restenosis in saphenous vein grafts versus native coronary arteries.
Intracoronary gamma radiation is effective in reducing recurrent in-stent restenosis (ISR) involving native coronary arteries. This study compares the effectiveness and safety of intracoronary gamma radiation for the treatment of ISR in saphenous vein grafts (SVGs) versus native coronary arteries. In the Washington Radiation for In-Stent restenosis Trial (WRIST) series of gamma radiation trials, 1,142 patients with ISR (230 in SVG and 912 in native coronary arteries) completed 6-month clinical follow-up. All patients underwent balloon angioplasty, atherectomy, and/or restenting. Different ribbon lengths containing 6 to 23 seeds of iridium-192 were used to cover lesion lengths <80 mm. The prescribed radiation doses were 14 or 15 Gy at 2-mm radial distance from the center of the source. Baseline demographics showed that patients with SVGs were older (65 +/- 13 vs 61 +/- 11 years, p <0.001), more likely male (79% vs 64%, p <0.001), had more multivessel coronary disease (81% vs 50%, p <0.001), and less diffuse lesions (17 +/- 10 vs 24 +/- 12 mm, p <0.001). At 6 months, event-free survival was similar for patients with SVG ISR and native coronary ISR (82% vs 84%, p = 0.35). The SVG ISR population had a low rate of late total occlusion (4.6%) and late thrombosis (3.5%). Thus, treatment of ISR with gamma radiation in SVGs had similar outcome to native coronary arteries. The use of gamma radiation for the treatment of ISR should expand to SVGs.
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Impact of intracoronary radiation on in-stent restenosis involving ostial lesions.
The aim of this study was to compare 6-month clinical outcomes of patients with in-stent restenosis (ISR) involving the ostium treated with intracoronary radiation therapy (IRT) compared to placebo therapy, and also to nonostial lesions treated with IRT. Coronary interventions in ostial lesions have a high rate of recurrence of restenosis. The impact of IRT on ostial ISR has been inadequately characterized. We assessed patients enrolled in gamma (192-iridium) and beta (90-yttrium, 32-phosphorus) radiation trials for ISR at the Washington Hospital Center. Of patients receiving IRT, 105 (8%) patients had ostial ISR and 1,289 (92%) patients had nonostial ISR. Twenty-seven patients had ostial ISR and received placebo therapy. Baseline demographic and angiographic and procedural details were similar, except ostial IRT patients had a trend toward shorter lesions (15.4 +/- 10.8 vs. 24.1 +/- 12.2 mm; P < 0.001) and had a higher rate of saphenous vein graft disease (46% vs. 19%; P < 0.001) compared to nonostial IRT patients. At 6 months, ostial lesions treated with IRT for ISR had a reduced rate of target lesion revascularization (TLR) compared to ostial lesions treated with placebo (15% vs. 43%; P = 0.004). Outcomes at 6 months were similar for the ostial and nonostial IRT groups including TLR (15% vs. 14%; P = 0.80) and composite major adverse cardiac events (18% vs. 15%; P = 0.46). Intracoronary radiation therapy is effective for ostial in-stent restenotic lesions and should be comfortably used for this challenging anatomic location.
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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.
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Late thrombosis after gamma-brachytherapy.
Late stent thrombosis (> 30 days after treatment) is a new phenomenon occurring after vascular brachytherapy. We report the analysis of 11 patients with late thrombosis after gamma-irradiation treatment of in-stent restenosis. All patients had in-stent restenosis and angina. Contributing factors to late thrombosis include long stents, small distal vessels, and complex lesion morphology.
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Use of restenting should be minimized with intracoronary radiation therapy for in-stent restenosis.
Restenting at the time of intracoronary radiation therapy (IRT) for in-stent restenosis (ISR) potentially increases the risk of late total occlusion (LTO) of the treated vessel. Prolonged antiplatelet therapy with clopidogrel (6 months) has been shown to be effective in reducing LTO risk. The purpose of this study was to assess the impact of restenting on clinical outcomes following IRT for ISR with 6 months of clopidogrel. We retrospectively evaluated 1,275 patients with 6-months clinical follow-up who were enrolled in radiation trials for ISR using gamma- and beta-emitters conducted at Washington Hospital Center. Patients were analyzed according to whether additional stents were deployed at the time of IRT. The predominant indication for restenting was to optimize the final angiographic result in the event of tissue prolapse or to cover edge dissections. All patients received a minimum of 6 months of clopidogrel. Baseline clinical and angiographic characteristics were similar between the restented and nonrestented groups. Radiation was delivered successfully in all cases. At 6 months, patients treated with additional stents and IRT had a significantly higher rate of target vessel revascularization than patients without additional stents (24.6% vs. 18.7%; P = 0.011). Restenting caused more frequent late thrombosis, late total occlusion, and Q-wave myocardial infarction than no restenting (4.0% vs. 2.2%, P = 0.09; 6.1% vs. 4.3%, P = 0.14; and 1.9% vs. 0.4%, P = 0.009, respectively). Restenting for the treatment of ISR is associated with increased adverse events and should be avoided after intracoronary radiation therapy for in-stent restenosis, as restenting results in a higher recurrence rate and the potential for increased late total occlusion.
Brachytherapy↗
Percutaneous interventions in radial artery grafts: clinical and angiographic outcomes.
In the modern era, radial artery graft is being used with increasing frequency to replace saphenous vein as a conduit for coronary artery bypass surgery. Several reports have shown encouraging early results of radial grafts compared to saphenous grafts. Despite these advantages, radial artery graft failure requiring revascularization does occur. We report on the clinical, angiographic, and technical characteristics and the follow-up results of 22 patients who underwent percutaneous intervention of radial grafts.
Adrenergic beta-Antagonists↗
Percutaneous coronary intervention-associated nephropathy foreshadows increased risk of late adverse events in patients with normal baseline serum creatinine.
In patients with chronic renal insufficiency, further decline in renal function (DRF) after percutaneous coronary intervention (PCI) is accompanied not only by adverse in-hospital events but also by increased risk of mortality and myocardial infarction at 1 year. This analysis was undertaken to determine if patients with normal renal function who develop DRF after PCI have a comparable increase in risk of death and myocardial infarction at 1 year, and whether this risk is independent of in-hospital complications (death, myocardial infarction, urgent coronary artery bypass grafting). We performed a retrospective analysis of all patients from a single center who underwent successful PCI with no major in-hospital complications who had pre-PCI serum creatinine (SCr) </= 1.2 mg/dl and no history of renal insufficiency. One-year follow-up was obtained by mail or telephone. There were 5,967 consecutive patients who met the inclusion criteria. Of these, 208 (3.5%) developed DRF (an increase in SCr >/= 50% of baseline). They were more likely to be older, female, non-Caucasian, diabetic and/or hypertensive. They reported more prior cerebral or peripheral vascular events. They had undergone more complex PCI and were exposed to more radiographic contrast than the 96.5% who did not develop DRF. After adjustment for baseline variables, DRF remained an independent predictor of 1-year mortality, myocardial infarction, and target vessel revascularization. In patients without prior renal impairment, DRF post-PCI is rare but is associated with an increased risk of late adverse cardiac events similar to that in chronic renal insufficiency patients.
Acute Kidney Injury↗
Impact of the acute results on the long-term outcome after the treatment of in-stent restenosis: a serial intravascular ultrasound study.
The current study used serial (postintervention and follow-up) intravascular ultrasound (IVUS) to assess the impact of acute results on long-term follow-up of patients with in-stent restenosis (ISR). All patients (n = 180) with serial IVUS studies of ISR lesions from the following gamma-irradiation brachytherapy trials were included: Washington Radiation for In-Stent Restenosis Trial (WRIST), Gamma-1, and Angiorad Radiation Technology for In-Stent Restenosis Trial in Native Coronaries (ARTISTIC). There were 106 irradiated and 74 placebo patients. Quantitative analysis was performed according to the American College of Cardiology Clinical Expert Consensus Document on Standards for Acquisition, Measurement and Reporting of IVUS. Images were acquired using motorized transducer pullback, cross-sectional analysis was performed every 1 mm, and volumetric and mean planar dimensions were calculated. The independent predictors for the absolute follow-up minimum lumen area (MLA) were the postintervention MLA, the postintervention minimum stent area, and the use of brachytherapy. Placebo patients lost 45% of the postintervention MLA while irradiated patients lost only 17% of the MLA. The independent predictors of the follow-up percent intimal hyperplasia (intimal hyperplasia volume divided by stent volume) and the independent predictors of the absolute increase in intimal hyperplasia were the postintervention percent intimal hyperplasia and the use of brachytherapy. Serial IVUS analysis shows that the follow-up MLA and percent intimal hyperplasia are dependent on the results obtained during the treatment of ISR lesions.
Brachytherapy↗
Additional stenting promotes intimal proliferation and compromises the results of intravascular radiation therapy: an intravascular ultrasound study.
BACKGROUND: Vascular brachytherapy (VBT) reduces in-stent restenosis (ISR). However, additional stenting at the time of radiation may be associated with a worse outcome. METHODS AND RESULTS: Intravascular ultrasound (IVUS) was performed after VBT and at 6 months follow-up in 79 native artery ISR patients treated with gamma-radiation who participated in the Washington Radiation for In-Stent restenosis Trial (WRIST), Gamma-1, and Angiorad Radiation Technology for In-Stent restenosis Trial in Coronaries (ARTISTIC) trials. Patients were treated with (192)Ir at 14 or 15 Gy at 2 mm from the source. Additional stents were used to treat the ISR lesions in 45 patients; these patients were then compared with the 34 patients treated without restenting. Paired measurements included stent, lumen, and intimal hyperplasia volumes. After the VBT procedure, intimal hyperplasia volume was smaller in the group treated with additional stents (54 +/- 33 mm(3) vs 34 +/- 33 mm(3), P =.012), but minimal lumen area was similar between the 2 groups (4.3 +/- 1.5 mm(2) vs 4.7 +/- 1.4 mm(2) respectively, P = NS). Between the time of the VBT procedure and follow-up, intimal hyperplasia volume increased by 27 +/- 19 mm(3) in the restented group and by 9 +/- 21 mm(3) in the group treated without additional stents (P =.014). At 6 months, intimal volume was similar in the 2 groups, but minimal lumen area was slightly smaller in the group treated with additional stents (3.4 +/- 1.8 mm(2) vs 4.2 +/- 1.7 mm(2), P =.053). Patients treated with additional stents had more target lesion revascularizations than the group treated without additional stents (38% vs 15%, P =.02). CONCLUSIONS: Additional stenting reduces intimal hyperplasia within the stents acutely. However, it compromises the benefit of VBT by promoting higher intimal regrowth within months after radiation.
Brachytherapy↗
Effect of direct stenting on clinical outcome in patients treated with percutaneous coronary intervention on saphenous vein graft.
BACKGROUND: Percutaneous coronary intervention (PCI) of saphenous vein graft (SVG) is associated with frequent postprocedural enzyme elevation and late cardiac events. New strategies are proposed to minimize distal embolization and to improve the outcome of patients treated with stenting for SVG lesions. The objectives of the current study were to examine direct stenting (DS) strategy of PCI in SVG lesions and its effects on creatine-kinase (CK) release, major adverse cardiac events (MACE), and late outcome when compared to conventional stenting (CS). METHODS: A consecutive series of 527 patients treated with stent implantation for SVG stenosis was analyzed. In this cohort, 170 patients with 229 lesions were treated with DS and 357 patients with 443 lesions were treated with CS. The inhospital and 12-month follow-up events were recorded and reported. RESULTS: Baseline clinical and postprocedural angiographic characteristics were similar between the 2 groups except for higher preprocedural prevalence of thrombus-containing lesions in the DS group. Patients in the DS group had less CK-MB release (P <.001), and less non-Q-wave myocardial infarction (P =.024). Multivariate analysis detected unstable angina (odds ratio [OR] = 1.8, P =.03) as a correlate for non-Q-wave MI; DS was inversely associated with non-Q-wave myocardial infarction (OR = 0.65, P =.04). At 1 year, the target lesion revascularization-MACE was significantly lower in the DS group (P =.021). Multivariate analysis showed that DS (OR = 0.47, P =.007) was associated with reduction of the target lesion revascularization-MACE. CONCLUSIONS: When feasible, DS may be the best approach for treating SVG stenosis.
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Understanding and preventing the edge effect.
Edge stenosis, combining neointimal proliferation and negative remodeling, remains a serious limitation of vascular brachytherapy. This review comprehensively presents terminology, definitions, mechanisms, and treatment strategies to better understand the complexities of edge narrowing. The major contributors to this phenomenon are known; understanding the practical solutions will enable us to further minimize the problem of the edge effect.
Brachytherapy↗
Late thrombosis: a problem solved?
Late thrombosis (angiographic total occlusion associated with an acute coronary syndrome) is a potentially life-threatening complication after intracoronary radiation therapy. This review is intended to explore the preclinical and clinical evidence for late thrombosis, to discuss the etiology, and to provide guidelines for future management. Although we have gained a greater understanding of this complex entity, further research is required in a quest to curtail late thrombosis rates.
Animals↗
Impact of renal function on morbidity and mortality after percutaneous aortocoronary saphenous vein graft intervention.
BACKGROUND: Percutaneous coronary intervention in patients with chronic renal insufficiency (CRI) and native coronary artery disease is often problematic, marred by increased morbidity and mortality rates and a high incidence of restenosis and revascularization. However, little is known about the effect of CRI in patients who have undergone prior coronary artery bypass graft surgery and then undergo saphenous vein graft (SVG) intervention. METHODS: We analyzed the inhospital and 1-year outcomes of 1265 consecutive patients with normal renal function and varying degrees of renal insufficiency who underwent percutaneous SVG intervention and divided them into 4 groups on the basis of the calculated creatinine clearance (CrCl): group 1, CrCl > or =70 mL per minute (n = 626); group 2, CrCl 50 to 69 mL per minute (n = 357); group 3, CrCl 30 to 49 mL per minute (n = 228); and group 4, CrCl <30 mL per minute (n = 54). Patients undergoing dialysis replacement therapy were excluded from the study. RESULTS: Patients with lower CrCl more often were older, female, had diabetes mellitus, and had worse left ventricular function. Angiographic baseline characteristics were comparable among the 4 groups. Overall immediate procedural success was similar for all groups. Patients with a low CrCl had significantly higher inhospital overall and cardiac mortality rates (P <.001), including a significantly higher incidence of myocardial infarction, vascular complications, pulmonary edema, and renal function deterioration. At 1-year follow-up, the overall mortality rates remained significantly higher in patients with decreased CrCl, with an incremental rise in overall mortality rate associated with lower renal function (P <.001). CONCLUSIONS: This study suggests that renal function is a primary determinate of short- and long-term survival in patients undergoing percutaneous SVG intervention and that there is a clear relationship between CrCl and cardiovascular outcome.
Age Factors↗
Review of intracoronary radiation for in-stent restenosis.
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Blood Vessel Prosthesis Implantation↗
Mechanisms and methods to resolve edge effect.
Vascular brachytherapy (VBT) has established itself as a viable modality to treat in-stent restenosis (ISR). The problems associated with VBT have been understood well and remedied. Late thrombosis has been overcome to a great extent by prolonged antiplatelet therapy. Edge effect is another important limitation of VBT and is due to inadequate radiation coverage of the edges following VBT. It may be overcome by confining injury to the lesion segment and extending the radiation sources by a few millimeters from the injured segment.
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