Drug-eluting coronary stents.
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Coronary Disease↗
Biomedical subjects
Ron Waksman
Publications and source records attributed to Ron Waksman.
Efficacy of sirolimus-eluting stents compared with bare metal stents for saphenous vein graft intervention.
Saphenous vein graft (SVG) intervention is associated with a significantly increased rate of periprocedural complications and late clinical and angiographic restenosis. We examined the efficacy and safety of sirolimus-eluting stents (SESs; Cypher) compared with bare metal stents (BMSs) in SVG intervention. Forty-eight patients who had 50 SVG lesions and underwent standard percutaneous coronary intervention with SESs (SES group) were compared with 57 patients who had 64 SVG lesions and underwent intervention with BMSs (BMS group). All patients received distal protection devices during SVG intervention. In-hospital, 30-day, 6-month, and 1-year clinical outcomes in the 2 groups were compared. Baseline clinical and procedural characteristics were balanced between groups. There were no deaths or Q-wave myocardial infarctions during the index hospitalization, but compared with the BMS group, patients in the SES group had significantly fewer non-Q-wave myocardial infarctions (4% vs 21%, p = 0.01), which was mainly attributed to increased periprocedural creatine kinase-MB levels. At 30-day, 6-month, and 1-year follow-ups, all clinical outcomes were similar between groups. Event-free survival at 1 year was also similar between groups (p = 0.84). In conclusion, the use of SESs in patients who undergo SVG intervention with a distal protection device is clinically safe and feasible but is not associated with decreased clinical events up to 1 year compared with BMSs.
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Cardiovascular events in patients with coronary plaque rupture and nonsignificant stenosis.
The long-term outcome of patients who present with an identified plaque rupture in a nonflow-limiting lesion is not well known. We retrospectively studied 17 consecutive patients in whom intravascular ultrasound identified plaque rupture in nonflow-limiting lesions (minimum lumen area >4.0 mm2) that were not treated with coronary intervention. After a mean follow-up of 43 +/- 25 months, events related to those lesions were 1 death (6%) of undetermined cause (6%) that occurred after 69 months, no myocardial infarction, and 2 revascularizations (12%) that occurred at 3 and 67 months. Overall, the cumulative rate of cardiac events was 18%.
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Impact of renal function on coronary plaque morphology and morphometry in patients with chronic renal insufficiency as determined by intravascular ultrasound volumetric analysis.
The aim of the present study was to use intravascular ultrasonography (IVUS) to assess plaque morphology and morphometry in patients with varying degrees of chronic renal insufficiency, including end-stage renal disease (ESRD) on dialysis replacement. Cardiovascular disease is the main cause of death for patients with chronic renal insufficiency, particularly in patients with ESRD. The impact of several degrees of renal insufficiency (including ESRD) on coronary plaque characteristics has not been determined. A total of 142 patients who underwent IVUS imaging of a de novo native coronary artery stenosis before percutaneous intervention were matched for age, gender, and diabetes and were grouped according to calculated creatinine clearance (CrCl): CrCl >70 ml/min (n = 39); CrCl 50 to 69 ml/min (n = 41); CrCl <50 ml/min, (n = 37), and ESRD (n = 25). Standard clinical, angiographic, and IVUS parameters were measured. The ESRD group had more African-American (p = 0.002) and hypertensive (p = 0.002) patients. No significant difference was found in any of the IVUS measurements among patients with CrCl >70, 50 to 69, and <50 ml/min: reference and lesion site arterial, lumen, and plaque areas and volumes, and arterial calcium (p = NS for all comparisons). Conversely, patients with ESRD had larger reference segment arterial and lumen areas and volumes; larger lesion site arterial, lumen, and plaque areas; and larger arcs of calcium (p <0.05 for all post hoc comparisons between patients with ESRD and patients with CrCl >70, 50 to 69, and <50 ml/min). Thus, chronic renal insufficiency in the absence of dialysis is not associated with increased reference segment or lesion site plaque burden and calcium. However, the transition to the need for dialysis is associated with progressive calcific atherosclerosis (larger lesion plaque area and calcium).
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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.
Coronary Restenosis↗
Intravascular ultrasound assessment of ruptured atherosclerotic plaques in left main coronary arteries.
Atherosclerotic plaque rupture is the main cause of acute coronary syndromes. There is no systematic description of ruptured plaques located in the left main coronary artery (LMCA). The aim of our study was to describe ruptured plaques in the LMCA with intravascular ultrasound. We identified 17 LMCA plaque ruptures in 16 patients. Two patients had a recent myocardial infarction, 13 had unstable angina, and 1 had stable angina. Two left main ruptures were clinically considered to be incidental findings and were left untreated; the remaining 14 were culprit lesions that were treated with emergency coronary artery bypass grafting (n = 3) or LMCA stenting (n = 11). One patient died in the hospital after left main stenting for unstable angina; all other patients who underwent stenting or surgical bypass did well. Almost all ruptured plaques that were identified by intravascular ultrasound had an angiographic complex appearance that was defined by the presence of ulceration (81%), intimal flap (38%), aneurysm (12%), or thrombus (6%). All ruptures were located in the distal half of the LMCA; 6 ruptures involved bifurcation and 11 were confined to the LMCA proper. The angle between the maximum plaque cavity and the left anterior descending/left circumflex artery flow divider was 162.3 degrees +/- 15.6 degrees in bifurcation versus 71.3 degrees +/- 41.6 degrees in nonbifurcation lesions (p <0.0001). The LMCA minimum lumen area measured 6.0 +/- 3.3 mm2 in nonbifurcation lesions and 7.4 +/- 4.7 mm2 in bifurcation lesions (p = 0.5). LMCA plaque ruptures mostly present as unstable angina, are located in the distal portion and/or bifurcation of the LMCA, often do not compromise the lumen, and have an angiographic complex appearance. When ruptured plaques involve the bifurcation, they occur opposite the distal flow divider.
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Impact of treatment of coronary artery disease with sirolimus-eluting stents on outcomes of diabetic and nondiabetic patients.
Patients with diabetes mellitus are at increased risk for repeat interventions and mortality after coronary angioplasty and stenting. The efficacy of sirolimus-eluting stents (SESs) to improve the outcomes of these patients is a focus of interest. In the first 1,407 patients treated with SESs at our institution, 492 were diabetic (insulin dependent diabetes mellitus [IDDM], n = 160 and non-insulin-dependent DM [NIDDM], n = 332). The in-hospital and 1- and 6-month clinical outcomes were compared with those of 915 patients without DM (non-DM). The baseline characteristics were similar, except for more women, obesity, previous myocardial infarction, coronary artery bypass grafting, and renal insufficiency in the DM group (p <0.001). Compared with non-DM patients, DM patients had higher in-hospital (p <0.05) and 1-month mortality (p = 0.02). IDDM patients had more in-hospital renal failure (p = 0.04) and Q-wave myocardial infarctions (1.6% vs 0%, p = 0.04) compared with NIDDM patients, and higher mortality (3.1% vs 0.8%, p = 0.04) and subacute stent thromboses (2.3% vs 0.5%, p = 0.07) than non-DM patients at 30 days. At 6 months, DM patients had a higher incidence of Q-wave myocardial infarction, target lesion revascularization-major adverse cardiac events, and composite of death and Q-wave myocardial infarction than non-DM patients (6.0% vs 2.7%, p = 0.01). Late outcomes between the IDDM and NIDDM groups were similar. Multivariate analysis showed diabetes and acute renal failure as independent predictors of target lesion revascularization-major adverse cardiac events. In conclusion, our data showed that, despite a reduction in repeat revascularization, coronary intervention with SESs in diabetic patients is limited by higher mortality at 1 month and a higher incidence of Q-wave myocardial infarction and target lesion revascularization-major adverse cardiac events at 6 months compared with non-DM patients. Careful surveillance is required in IDDM patients undergoing SES implantation.
Angioplasty, Balloon, Coronary↗
Bivalirudin versus heparin as an antithrombotic agent in patients who undergo percutaneous saphenous vein graft intervention with a distal protection device.
Bivalirudin (Angiomax) is increasingly used as a substitute for heparin in a variety of percutaneous coronary interventions, and data on its usage in saphenous vein graft interventions are limited. This retrospective, observational study evaluated the efficacy and safety of bivalirudin compared with heparin as an antithrombotic regimen in patients who underwent saphenous vein graft intervention with distal protection devices. We found that bivalirudin use is clinically safe and feasible, with fewer vascular and ischemic complications compared with heparin.
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Incidence and clinical correlates of ruptured plaques in saphenous vein grafts: an intravascular ultrasound study.
OBJECTIVES: The goal of this study was to assess the incidence, clinical correlates, and angiographic appearance of ruptured atherosclerotic plaques detected in saphenous vein grafts (SVGs). BACKGROUND: Ruptured atherosclerotic plaques in native coronary arteries but not in SVGs have been well described with intravascular ultrasound (IVUS). METHODS: We reviewed 791 pre-intervention IVUS SVG studies and identified 95 ruptured plaques in 76 SVGs in 73 patients. Standard clinical, angiographic, and IVUS measurements were collected and/or measured. Ruptured plaques were compared with nonruptured plaques in 276 randomly selected patients. RESULTS: The IVUS-detected ruptured plaques had angiographically complex morphology (95%) with ulceration (79%), intimal flap (71%), and sometimes aneurysm formation (14%). Compared with control SVG lesions, ruptured plaques occurred more often in patients with acute coronary syndromes, in older SVGs (12.3 +/- 5.0 years vs. 8.6 +/- 5.2 years, p < 0.001), and in patients with hypercholesterolemia (92% vs. 81%, p = 0.021) and hypertension (78% vs. 63%, p = 0.015). Multiple ruptured plaques were identified in 22 patients in 19 grafts, more often in diabetic patients (55% vs. 29%, p = 0.054). A tear in the fibrous cap could be identified in 59% of plaques; in 70% it occurred at the shoulder of the plaque and in 30% at the center of the plaque. The IVUS features of ruptured plaques included positive remodeling in 71%, which was more common than in control plaques (40%, p < 0.001). CONCLUSIONS: Ruptured atherosclerotic plaques occur in old SVGs with an incidence of 9.7%. These lesions have a complex angiographic appearance and positive remodeling characteristics. This is similar to ruptured plaques in native arteries.
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Intravascular ultrasound stent area of sirolimus-eluting stents and its impact on late outcome.
Stent area assessed by intravascular ultrasound is a strong predictor of late outcome after percutaneous coronary intervention. Because sirolimus-eluting stents (SESs) prevent intimal regrowth within the stent, achieving a larger final stent area might no longer be noteworthy; therefore, the investigators sought to determine the relevance and impact of the final stent area with SESs.
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Real-world clinical practice of intracoronary radiation therapy as compared to investigational trials.
Intracoronary radiation therapy (IRT) is well established in clinical practice as an effective treatment for in-stent restenosis. We aimed to determine if the 6-month clinical outcome of patients treated postapproval for marketing [commercial radiation (CR)] is equivalent to those patients enrolled in the Washington Radiation for In-Stent Restenosis Trials [Gamma WRIST and Beta WRIST; investigational radiation (IR)]. The 6-month clinical outcome of 110 consecutive patients with 125 lesions who received IRT (gamma, (192)Ir, 15-18 Gy, n = 6; or beta, (32)P, 20 Gy, n = 20; or (90)Sr/Y, 18.4-23.0 Gy, n = 99) in CR was compared with the 6-month clinical outcome of 117 patients with 117 lesions who received IRT ((192)Ir, 15 Gy, n = 65, in Gamma WRIST; and (90)Y, 20.6 Gy, n = 52, in Beta WRIST) in IR. Patients in CR were treated with wider radiation margins. The CR received antiplatelet therapy for at least 6 months and the IR for 1 month. The baseline characteristics of both groups were similar. Use of atheroablation devices was less in CR than IR (15.2% vs. 32.8%, respectively; P = 0.001). The overall major adverse cardiac events (death, Q-wave myocardial infarction, and target vessel revascularization; 18.2% vs. 29.1% in IR; P = 0.05) were significantly lower in the CR when compared with patients in the IR. The real-world clinical practice of IRT demonstrates lower events and better clinical outcomes. This is most likely a result of implementation of the lessons learned from the clinical trials such as optimizing the dosimetry by using a higher dose, treating wider margins to minimize edge effect, and administering prolonged antiplatelet therapy to abolish late thrombosis.
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Internet-based teleangiography: an indispensable tool for the interventional cardiologist.
Efficient and effective communication of specific patient information between referring and consulting physicians has become increasingly important with the need to evaluate a variety of treatment strategies, including coronary bypass surgery, coronary intervention, and medical therapy, without prolonging hospital stay. Until recently, the options available were either slow (mail or courier) or costly and cumbersome (hardware-based digital solutions). eMedcon, a new, easy-to-install Internet-based software solution described in this article, offers a quick and inexpensive solution to image digital cine transfer. eMedcon was tested at our institution, Washington Hospital Center, and was found to transmit images effectively and rapidly between physicians at any Internet-accessible site and Washington Hospital Center. Our data indicate that use of eMedcon led to an increase in repeat referrals and an increase in the number of physicians choosing to refer their patients to our institution.
Coronary Angiography↗
Novel site-specific systemic delivery of Rapamycin with perfluorobutane gas microbubble carrier reduced neointimal formation in a porcine coronary restenosis model.
Earlier studies demonstrated that perfluorobutane gas microbubble carrier (PGMC) adheres to injured arteries and enhances the drug uptake specifically into the cells of the denuded vessel segment. The purpose of this study was to investigate the effect of PGMC-based systemic delivery of Rapamycin on expression of p27 in vascular tissue and restenosis in porcine coronary arteries after stent implantation. Eight pigs underwent coronary stent implantation (three stents per animal). Five pigs were treated with i.v. injection of PGMC with 2 mg of Rapamycin and three animals served as control. Four hours postprocedure, three pigs were sacrificed and stented segments were analyzed by high-performance liquid chromatography (HPLC) and Western blot. In chronic experiments, five pigs (15 stent sites) were sacrificed at 28 days following intervention and vessels were perfusion-fixed. HPLC of the treated arteries demonstrated high drug concentration in the vessel tissue, and Western blot analysis showed elevated expression of p27 at 4 hr postprocedure. Histomorphometry revealed significantly reduced (by 40%) neointimal formation in the PGMC/Rapamycin group compared with controls (1.84 +/- 0.84 vs. 4.77 +/- 1.71 mm2, respectively; P < 0.001). In the porcine coronary model, site-specific systemic delivery of Rapamycin utilizing PGMC resulted in overexpression of p27 and a significant reduction of neointimal formation within the stented segments.
Animals↗
Underexpansion of sirolimus-eluting stents: incidence and relationship to delivery pressure.
We aimed to assess the incidence of underexpansion and the relationship between delivery pressure and expansion with sirolimus-eluting stents. Adequate stent expansion contributes to early and late improved outcomes. In 51 patients (53 lesions) with native coronary artery narrowing, balloon-expandable sirolimus-eluting stents (Cypher) were serially expanded with gradual balloon inflations [14 atm, 20 atm, and in case of minimal stent cross-sectional area (CSA)/reference lumen CSA < 50% at 20 atm, postdilatation with 0.5 mm larger balloon]. Intravascular ultrasound (IVUS) imaging was performed before intervention and after each gradual balloon inflation. Stent expansion (minimal stent CSA/reference lumen CSA) was measured. Stent expansion was 72% +/- 16% after 14 atm balloon inflation, 90% +/- 18% after 20 atm balloon inflation (P < 0.001 vs. 14 atm), and 90% +/- 18% at the end of the procedure (including optional postdilatations with 0.5 mm larger balloon; P = NS vs. 20 atm). Stent expansion addressed by MUSIC criteria (all struts apposed, no tissue protrusion, and final lumen CSA > 80% of the reference or > 90% if minimal lumen CSA was < 9 mm2) was adequate in 15% of the cases after 14 atm balloon inflation, in 60% after 20 atm balloon inflation (P < 0.001 vs. 14 atm), and in 60% at the end of the procedure (P = NS vs. 20 atm). Sirolimus-eluting stent underexpansion is common when deployed at conventional pressures. Increasing balloon delivery pressure or assessing stent expansion with IVUS seems warranted in order to ensure adequate sirolimus-eluting stent deployment.
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Three-year follow-up after intravascular gamma-radiation for in-stent restenosis in saphenous vein grafts.
The Washington Radiation for In-Stent Restenosis Trial in Saphenous Vein Grafts (SVG WRIST) demonstrated safety and efficacy of intravascular radiation therapy (IRT) for the treatment of in-stent restenosis (ISR) in SVG at 12 months. In this study, we aimed to examine whether the safety and efficacy of IRT is durable up to 36 months. One hundred twenty patients with diffuse ISR in SVG underwent balloon angioplasty, laser or atherectomy ablation, and/or additional stenting. After successful intervention, patients were randomly assigned in a double-blind fashion to intravascular treatment with a ribbon containing either iridium (Ir)-192 (n = 60) or nonradioactive seeds (n = 60). The prescribed dose at 2 mm from the source was either 14 or 15 Gy in vessels 2.5-4.0 mm or 18 Gy in vessels > 4.0 mm in diameter. At 36 months, target lesion revascularization (TLR; 43% vs. 66%; P = 0.02) and target lesion revascularization-major adverse cardiac event (TLR-MACE; 49% vs. 71%; P = 0.02) rates continued to be lower in the IRT group, but both target vessel revascularization (TVR; 59% vs. 71%; P = 0.17) and TVR-MACE (63% vs. 77%; P = 0.11) rates were not. In SVG WRIST, patients with ISR treated with IRT had a marked reduction in the need for repeat TLR at 36 months, with sustained clinical benefit at 3 years despite late recurrences, which were more pronounced in the radiation group.
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Impact of sirolimus-eluting stents on outcomes of patients treated for acute myocardial infarction by primary angioplasty.
Sirolimus-eluting stents (SESs) are currently being used in patients undergoing percutaneous coronary intervention (PCI). SESs have not been evaluated in the treatment of acute myocardial infarction by primary angioplasty. We report our initial experience with SESs implanted during primary angioplasty. One hundred and three patients were treated within 12 hr after onset of acute myocardial infarction (AMI) with primary angioplasty and SES implantation. Those patients were compared to 504 patients treated with bare metal stents (BMSs). Angiographic success (TIMI flow grade 3 and residual stenosis < 50%) was completed in 98% of patients with SESs and no subacute stent thrombosis was reported. In-hospital outcomes were similar in the SES and BMS groups. At 6 months, major cardiac events were less frequent in the SES group than in the BMS group (9% vs. 24%, respectively; P < 0.001), driven by a lesser need for repeat revascularization with SESs (1% vs. 10.3% with BMSs; P = 0.014). Mortality at 6 months was 7% with SESs and 11% with BMSs (P = 0.14). SESs are safe and effective for the treatment of AMI by primary angioplasty. As compared to BMSs, SESs improve long-term outcome after AMI, mainly by reducing the need for repeat revascularization.
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Mysteries behind stent struts.
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Angioplasty, Balloon, Coronary↗
Selective versus exclusive use of sirolimus-eluting stent implantation in multivessel coronary artery disease.
Sirolimus-eluting stents (SESs; Cypher) have demonstrated a significant reduction in restenosis rates when compared to bare metal stents (BMSs). The purpose of this study was to evaluate the strategy of exclusive use of two SESs versus the combination of one BMS and one SES for two-vessel coronary artery disease (CAD). It was found that the selective use of one SES combined with one BMS in patients undergoing percutaneous coronary intervention that requires more than one stent is safe, feasible, and associated with favorable procedural, 30-day, and 6-month clinical outcomes when compared to the exclusive use of SESs.
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