Echolucent neointimal hyperplasia "dark wall" after sirolimus eluting stent implantation.
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Coronary Angiography↗
Biomedical subjects
M B Leon
Publications and source records attributed to M B Leon.
Late incomplete lesion coverage following Cypher stent deployment for diffuse right coronary artery stenosis.
The availability of the only drug eluting stent currently approved in the USA has been limited, so that operators often resort to the deployment of multiple undersized stents and post-stenting high pressure inflations with larger balloons to achieve optimal lesion coverage and stent expansion. A case of stent fracture following percutaneous coronary intervention in which this strategy was used is reported.
Angioplasty, Balloon, Coronary↗
[Percutaneous artificial heart valves: from animal experimentation to the first human implantation in a case of calcified aortic stenosis].
The development of artificial cardiac valves capable of being positioned by catheter has become an important subject for research, with the objective of treating valvular patients who are not operable or at very high surgical risk. We tested an artificial valve implantable by the percutaneous route, consisting of three leaflets of bovine pericardium sutured to the inside of a stainless steel stent, deployable by inflating a balloon. Following laboratory evaluation, this valve was implanted with success in animals, then for the first time in man, in a case of calcified aortic stenosis. The patient, a 57 year old male in cardiogenic shock, had associated multiple non-cardiac pathology and could not be operated on. Implantation was carried out by the trans-septal anterograde route, the only route available due to severe end stage arteritis. The artificial valve was deposited in the centre of the native aortic valve, without obstructing the coronaries nor reaching the mitral valve. The result was spectacular with instantaneous haemodynamic improvement and excellent valvular function confirmed by transoesophageal echocardiography every 15 days after implantation. Non-cardiac complications marred the progress, dominated by aggravation of pre-existing leg ischaemia, necessitating amputation for which the consequences were fatal at 4 months. This case demonstrates that implantation of a cardiac valve by the percutaneous route is possible in calcified aortic stenosis, and that it brings rapid clinical improvement. This technique could in future constitute an important alternative therapeutic approach for selected patients.
Angioplasty, Balloon↗
[Recent trend in interventional cardiology--drug-containing stents].
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Angioplasty, Balloon, Coronary↗
Effect of the distal-balloon protection system on microembolization during carotid stenting.
BACKGROUND: The distal-balloon protection system is being evaluated for its efficacy in preventing embolic neurological events during carotid stenting (CAS). We sought to determine the effect of this system on the frequency of Doppler-detected microembolic signals (MES) during CAS. METHODS AND RESULTS: Using transcranial Doppler, we compared the frequency of MES during CAS in 2 groups: 39 patients without distal protection and 37 who used the distal-balloon protection system (GuardWire). There were no significant differences in the clinical or angiographic characteristics between the 2 groups. Three phases with increased MES counts were identified during unprotected CAS; these were stent deployment, predilation, and postdilation (75+/-57, 32+/-36, and 27+/-25 METS, respectively). The distal-balloon protection significantly reduced the frequency of MES during CAS (MES counts: 164+/-108 in the control versus 68+/-83 in the protection group; P=0.002), particularly during these 3 phases. MES in the protection group were detected predominantly during sheath placement, guidewire manipulation, and distal-balloon deflation. CONCLUSION: Three phases with increased MES counts were identified during unprotected CAS (eg, stent deployment, predilation, and postdilation). The distal-balloon protection system significantly reduced the frequency of MES during CAS, particularly during these 3 phases.
Aged↗
Effect of short pulsed nonablative infrared laser irradiation on vascular cells in vitro and neointimal hyperplasia in a rabbit balloon injury model.
BACKGROUND: Neointimal hyperplasia after PTCA is an important component of restenosis. METHODS AND RESULTS: Cultures of rabbit endothelial cells and smooth muscle cells (SMCs) were irradiated with different doses of nonablative infrared (1064-nm) radiation. Normalized viability index detected with nondestructive Alamar Blue assay and direct cell count were studied. Our experiments demonstrated dose-dependent cytostatic or cytotoxic effects of laser irradiation. We also evaluated the long-term effect of endoluminal nonablative infrared laser irradiation on neointimal hyperplasia in a rabbit balloon injury model. PTCA of both iliac arteries of 23 New Zealand White rabbits was performed. One iliac artery was subjected to intra-arterial subablative infrared irradiation via a diffuse tip fiber. The contralateral vessel served as control. The diet was supplemented with 0.25% cholesterol and 2% peanut oil for 10 days before and 60 days after PTCA. Morphometry after 60 days showed that intimal areas were 0.76+/-0.18 and 1.85+/-0.30 mm(2) in the laser and control arteries, respectively (P=2.2x10(-11)). CONCLUSIONS: We conclude that nonablative infrared laser inhibited neointimal hyperplasia after PTCA in cholesterol-fed rabbits for up to 60 days.
Angioplasty, Balloon, Coronary↗
Stent-based delivery of sirolimus reduces neointimal formation in a porcine coronary model.
BACKGROUND: The purpose of this study was to determine the efficacy of stent-based delivery of sirolimus (SRL) alone or in combination with dexamethasone (DEX) to reduce in-stent neointimal hyperplasia. SRL is a potent immunosuppressive agent that inhibits SMC proliferation by blocking cell cycle progression. METHODS AND RESULTS: Stents were coated with a nonerodable polymer containing 185 microgram SRL, 350 microgram DEX, or 185 microgram SRL and 350 microgram DEX. Polymer biocompatibility studies in the porcine and canine models showed acceptable tissue response at 60 days. Forty-seven stents (metal, n=13; SRL, n=13; DEX, n=13; SRL and DEX, n=8) were implanted in the coronary arteries of 16 pigs. The tissue level of SRL was 97+/-13 ng/artery, with a stent content of 71+/-10 microgram at 3 days. At 7 days, proliferating cell nuclear antigen and retinoblastoma protein expression were reduced 60% and 50%, respectively, by the SRL stents. After 28 days, the mean neointimal area was 2.47+/-1.04 mm(2) for the SRL alone and 2.42+/-1.04 mm(2) for the combination of SRL and DEX compared with the metal (5.06+/-1.88 mm(2), P<0.0001) or DEX-coated stents (4.31+/-3.21 mm(2), P<0.001), resulting in a 50% reduction of percent in-stent stenosis. CONCLUSIONS: Stent-based delivery of SRL via a nonerodable polymer matrix is feasible and effectively reduces in-stent neointimal hyperplasia by inhibiting cellular proliferation.
Animals↗
Differential impact on survival of electrocardiographic Q-wave versus enzymatic myocardial infarction after percutaneous intervention: a device-specific analysis of 7147 patients.
BACKGROUND: The relative prognostic importance of ECG myocardial infarction (MI) after intervention compared with varying degrees of enzymatic elevation has not been characterized, and the device-specific implications of periprocedural MI are also unknown. METHODS AND RESULTS: Serial creatine phosphokinase (CPK)-MB levels were determined after elective percutaneous intervention of 12 098 lesions in 7147 consecutive patients at a tertiary referral center. Procedural, in-hospital, and follow-up data were collected by independent research nurses, and clinical and ECG events were adjudicated by a separate committee. Stents were implanted in 50.6% of lesions, atheroablation was performed in 54.8%, and PTCA alone was performed in 9.8%. The peak periprocedural CPK-MB level was >3x the upper limit of normal (ULN) in 17.9% of patients, and Q-wave MI developed in 0.6%. By multivariate analysis, the periprocedural development of new Q waves was the most powerful independent determinant of death (2-year mortality rate, 38.3%; hazard ratio, 9.9; P<0.0001). Non-Q-wave MI with CPK-MB >8x ULN was also a strong predictor of death (2-year mortality rate, 16.3%; hazard ratio, 2.2; P<0.0001); survival was unaffected by lesser degrees of CPK-MB elevation. Though CPK-MB elevation was more common after atheroablation and stenting than PTCA, the rates of Q-wave MI and survival were device-independent. CONCLUSIONS: Myonecrosis after percutaneous intervention is common in a high-risk referral population dominated by atheroablation and stent use. Large periprocedural infarctions (signified by new Q waves and CPK-MB >8xULN) are powerful determinants of death, whereas lesser degrees of CPK-MB release and specific device use do not adversely affect survival.
Aged↗
Extent and distribution of in-stent intimal hyperplasia and edge effect in a non-radiation stent population.
Intimal hyperplasia within the body of the stent is the primary mechanism for in-stent restenosis; however, stent edge restenosis has been described after brachytherapy. Our current understanding about the magnitude of in vivo intimal hyperplasia and edge restenosis is limited to data obtained primarily from select, symptomatic patients requiring repeat angiography. The purpose of this study was to determine the extent and distribution of intimal hyperplasia both within the stent and along the stent edge in relatively nonselect, asymptomatic patients scheduled for 6-month intravascular ultrasound (IVUS) as part of a multicenter trial: Heparin Infusion Prior to Stenting. Planar IVUS measurements 1 mm apart were obtained throughout the stent and over a length of 10 mm proximal and distal to the stent at index and follow-up. Of the 179 patients enrolled, 140 returned for repeat angiography and IVUS at 6.4 +/- 1.9 months and had IVUS images adequate for analysis. Patients had 1.2 +/- 0.6 Palmaz-Schatz stents per vessel. There was a wide individual variation of intimal hyperplasia distribution within the stent and no mean predilection for any location. At 6 months, intimal hyperplasia occupied 29.3 +/- 16.2% of the stent volume on average. Lumen loss within 2 mm of the stent edge was due primarily to intimal proliferation. Beyond 2 mm, negative remodeling contributed more to lumen loss. Gender, age, vessel location, index plaque burden, hypercholesterolemia, diabetes, and tobacco did not predict luminal narrowing at the stent edges, but diabetes, unstable angina at presentation, and lesion length were predictive of in-stent intimal hyperplasia. In a non-radiation stent population, 29% of the stent volume is filled with intimal hyperplasia at 6 months. Lumen loss at the stent edge is due primarily to intimal proliferation.
Coronary Disease↗
Transcatheter therapeutic embolization of multiple coronary artery fistulas.
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Arterio-Arterial Fistula↗
Creatine kinase-MB fraction elevation after percutaneous coronary intervention in patients with chronic renal failure.
We evaluated the short- and long-term clinical outcomes of 326 consecutive patients with chronic renal failure, not on dialysis, who had creatine kinase (CK)-myocardial band (MB) fraction elevation after successful percutaneous coronary intervention in a native coronary artery. Based on peak CK-MB levels measured after intervention, patients were divided into 3 groups: no elevation (group 1, n = 184), 1 to 3 x upper normal levels (group 2, n = 72), and >3 x upper normal levels (group 3, n = 70). Baseline clinical and angiographic characteristics were similar among the 3 groups. Angiographic success was similar among the 3 groups, although there was a significantly higher use of intra-aortic balloon pump in patients who had postprocedural CK-MB >3 x normal values and a higher rate of in-hospital complications, i.e., repeat catheterization, repeat target lesion intervention, pulmonary edema, renal function deterioration, emergency dialysis, and major bleeding complications. At 1-year follow-up, mortality rates were significantly higher in these patients (35.4% vs 22.0% for patients with CK-MB 1 to 3 x normal values and 16.7% for patients without CK-MB elevation, p = 0.007). Multivariate analysis showed that CK-MB >3 x normal (odds ratio 3.04; 95% confidence interval 1.41 to 6.57, p = 0.005) and intra-aortic balloon pump (odds ratio 1.49; confidence interval 1.15 to 1.93, p = 0.002) were independent predictors of late mortality. Therefore, patients with chronic renal failure who had CK-MB elevation >3 x the upper normal limit after a successful percutaneous coronary intervention had a higher incidence of in-hospital complications and a significantly higher mortality rate at 1-year follow-up than patients without CK-MB elevation or with <3 x normal CK-MB elevation.
Aged↗
Serial intravascular ultrasound analysis of edge recurrence after intracoronary gamma radiation treatment of native artery in-stent restenosis lesions.
In the Washington Radiation for In-Stent restenosis Trial (WRIST), patients were first treated with conventional techniques and then randomized to either gamma-irradiation ((192)Ir) or placebo (dummy seeds). In the (192)Ir group with native coronary in-stent restenosis, we identified 8 patients with edge recurrence and compared them with 21 patients with no recurrence. Serial (postirradiation and follow-up) intravascular ultrasound analysis was performed according to conventional methods. When compared with nonrecurring lesions, lesions with distal edge recurrence had (1) greater decrease in mean distal lumen cross-sectional area (-3.0 +/- 1.2 vs -0.7 +/- 1.0 mm(2), p = 0.0002), (2) no change in mean distal external elastic membrane cross-sectional area versus an increase in mean distal cross-sectional area of 1.0 +/- 0.9 mm(2) in nonrecurring lesions (p = 0.0047), and (3) a greater increase in mean distal plaque + media cross-sectional area (2.9 +/- 1.2 mm vs 1.7 +/- 0.6 mm(2), p = 0.0103). Within the stented segment, the nonrecurring lesions had no decrease in mean lumen and no increase in mean intimal hyperplasia cross-sectional area. Conversely, lesions with distal edge recurrence had a significant decrease in mean intrastent lumen cross-sectional area (-1.7 +/- 1.7 mm(2)) and a significant increase in mean intrastent intimal hyperplasia cross-sectional area (1.6 +/- 1.6 mm(2)). Lesions with distal edge recurrence also had a greater decrease in mean proximal lumen cross-sectional area (-1.7 +/- 1.3 vs -0.3 +/- 0.8 mm(2), p = 0.0213), with a trend toward a greater increase in mean proximal plaque + media cross-sectional area. Thus, edge recurrence after (192)Ir treatment of in-stent restenosis is the result of neointimal hyperplasia (part of generalized treatment failure) and the absence of radiation-induced positive remodeling.
Brachytherapy↗
Comparison of endocardial electromechanical mapping with radionuclide perfusion imaging to assess myocardial viability and severity of myocardial ischemia in angina pectoris.
The assessment of left ventricular electromechanical activity using a novel, nonfluoroscopic 3-dimensional mapping system demonstrates considerable differences in electrical and mechanical activities within regions of myocardial infarction or ischemia. We sought to determine whether these changes correlate with indexes of myocardial perfusion, viability, or ischemia. A 12-segment comparative analysis was performed in 61 patients (45 men, 61 +/- 12 years old) with class III to IV angina, having reversible and/or fixed myocardial perfusion defects on single-photon emission computed tomographic perfusion imaging. A dual-isotope protocol was used, consisting of rest and 4-hour redistribution thallium images followed by adenosine technetium-99m sestamibi imaging. Average rest endocardial unipolar voltage (UpV) and local shortening (LS) mapping values were compared with visually derived perfusion scores. There was gradual and proportional reduction in regional UpV and LS in relation to thallium-201 uptake score at rest (p = 0.0001 and p = 0.0002, respectively) and redistribution studies (p = 0.0001 and p = 0.003, respectively). UpV > or = 7.4 mV and LS > or = 5.0% had a sensitivity of 78% and 65%, respectively, with a specificity of 68% and 67% for detecting viable myocardium. UpV values of 12.3 and 5.4 mV had 90% specificity and sensitivity, respectively, to predict viable tissue. UpV, but not LS, values differentiated between normal segments and those with adenosine-induced severe perfusion defects (11.8 +/- 5.3 vs 8.8 +/- 4.1 mV, p = 0.005). Catheter-based left ventricular assessment of electromechanical activity correlates with the degree of single-photon emission computed tomographic perfusion abnormality and can identify myocardial viability with a greater accuracy than myocardial ischemia.
Adenosine↗
Relation between preintervention remodeling and late arterial responses to coronary angioplasty or atherectomy.
We used the serial intravascular ultrasound (IVUS) data from the Serial Ultrasound REstenosis trial to explain why positive remodeling lesions have a higher rate of clinical restenosis after non-stent interventions. Serial IVUS was performed before intervention and immediately and 1 and 6 months after percutaneous transluminal coronary angioplasty (n = 35) or directional coronary atherectomy (n = 26). External elastic membrane, lumen, and plaque + media (external elastic membrane minus lumen) areas were measured at the reference and stenosis. Stenoses were divided into 3 groups: positive remodeling (lesion greater than proximal reference external elastic membrane), intermediate remodeling (lesion external elastic membrane smaller than proximal reference but larger than distal reference), and negative remodeling (lesion equal to or less than distal reference external elastic membrane). The early (postintervention to 1 month) and late (1- to 6-month) changes in lesion external elastic membrane and plaque + media areas were compared. An early increase in plaque + media area was associated with an equal or greater increase in external elastic membrane area in positive (r = 0.78, p < 0.0001), intermediate (r = 0.69, p < 0.0001), and negative (r = 0.59, p = 0.0003) remodeling lesions. A late (1- to 6-month) decrease in external elastic membrane area correlated inversely with the early increase in plaque + media area in positive (r = 0.77, p = 0.0002) and intermediate (r = 0.45, p = 0.0003), but not in negative (r = 0.02, p = 0.9) remodeling lesions. In positive remodeling lesions, the early increase in plaque + media area was associated with both an exaggerated early increase and late decrease in external elastic membrane area. Positive remodeling lesions have an exaggerated early increase in external elastic membrane area and, especially, an exaggerated late decrease in external elastic membrane area after percutaneous transluminal coronary angioplasty and directional coronary atherectomy. This may explain that the increased clinical restenosis after positive remodeling lesions is treated with non-stent interventions.
Analysis of Variance↗
Influence of gender on early and one-year clinical outcomes after saphenous vein graft stenting.
Compared with men, women may have a worse prognosis after native coronary revascularization. However, the influence of gender on clinical outcomes after saphenous vein graft (SVG) stenting is unknown. The purpose of this study was to compare early and 1-year clinical outcomes between men and women after stent implantation in SVG. A total of 1,199 consecutive patients with 1,858 SVG lesions were studied. Procedural success, in-hospital events, and late clinical outcomes were compared between men (n = 951) and women (n = 248). Overall procedural success was similar between men and women (97% vs 96%, p = NS). However, in-hospital (3.2% vs 1.6%, p = 0.07) and 30-day cumulative (4.4% vs 1.9%, p = 0.02) mortality rates were higher in women than in men. In addition, women had a higher incidence of vascular complications (12% vs 7.3%, p = 0.006) and postprocedural acute renal failure (8.1% vs 4%, p = 0.02). At 1-year follow-up, mortality was 13% in women and 11% in men (p = NS) and target lesion revascularization was 18% versus 23%, respectively (p = NS). By multivariate regression analysis, independent correlates of in-hospital mortality were female gender (odds ratio [OR] 3.6, confidence interval [CI] 1.0 to 12.5, p = 0.05) and left ventricular ejection fraction (OR 0.9, CI 0.9 to 1.0, p = 0.01). Female gender was found to predict 30-day mortality (OR 2.5, CI 1.1 to 5.5, p = 0.02). The sole predictor of 1-year mortality was diabetes mellitus (OR 1.6, CI 1.1 to 2.3, p = 0.01). This study shows that women compared with men treated with stent implantation in SVG lesions have (1) a trend toward higher in-hospital mortality, (2) higher risk of 30-day mortality, (3) increased incidence of vascular complications and postprocedure acute renal failure, and (4) similar 1-year clinical outcome.
Aged↗
Combination therapy with aspirin plus clopidogrel versus aspirin plus ticlopidine for prevention of subacute thrombosis after successful native coronary stenting.
We compared the combination of aspirin plus clopidrogrel (A+C) with aspirin and ticlopidine (A+T) for prevention of subacute stent thrombosis in 827 patients. At 30-day follow-up, there were trends toward increased subacute thrombosis with A+C compared with A+T (1.3% vs 0.2%, p = 0.10). These results suggest that A+C may have marginally higher subacute stent thrombosis than A+T.
Aged↗
Localized intracoronary gamma-radiation therapy to inhibit the recurrence of restenosis after stenting.
BACKGROUND: Although the frequency of restenosis after coronary angioplasty is reduced by stenting, when restenosis develops within a stent, the risk of subsequent restenosis is greater than 50 percent. We report on a multicenter, double-blind, randomized trial of intracoronary radiation therapy for the treatment of in-stent restenosis. METHODS: Of 252 eligible patients in whom in-stent restenosis had developed, 131 were randomly assigned to receive an indwelling intracoronary ribbon containing a sealed source of iridium-192, and 121 were assigned to receive a similar-appearing nonradioactive ribbon (placebo). RESULTS: The primary end point, a composite of death, myocardial infarction, and the need for repeated revascularization of the target lesion during nine months of follow-up, occurred in 53 patients assigned to placebo (43.8 percent) and 37 patients assigned to iridium-192 (28.2 percent, P=0.02). However, the reduction in the incidence of major adverse cardiac events was determined solely by a diminished need for revascularization of the target lesion, not by reductions in the incidence of death or myocardial infarction. Late thrombosis occurred in 5.3 percent of the iridium-192 group, as compared with 0.8 percent of the placebo group (P=0.07), resulting in more late myocardial infarctions in the iridium-192 group (9.9 percent vs. 4.1 percent, P=0.09). Late thrombosis occurred in irradiated patients only after the discontinuation of oral antiplatelet therapy (with ticlopidine or clopidogrel) and only in patients who had received new stents at the time of radiation treatment. CONCLUSIONS: Intracoronary irradiation with iridium-192 resulted in lower rates of clinical and angiographic restenosis, although it was also associated with a higher rate of late thrombosis, resulting in an increased risk of myocardial infarction. If the problem of late thrombosis within the stent can be overcome, intracoronary irradiation with iridium-192 may become a useful approach to the treatment of in-stent restenosis.
Angioplasty, Balloon, Coronary↗
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.
Brachytherapy↗