Mechanism of lumen enlargement with direct stenting versus predilatation stenting: influence of remodelling and plaque characteristics assessed by volumetric intracoronary ultrasound.

OBJECTIVE: To compare the effects of arterial remodelling and plaque characteristics on the mechanisms of direct stenting and predilatation stenting. Direct stenting has become routine in some laboratories and differs technically from predilatation stenting. METHODS: Pre- and post-interventional volumetric intravascular ultrasound (IVUS) was undertaken in 30 patients with direct stenting and in 30 with predilatation stenting of non-calcified native coronary lesions, using the same stent design and stent length. Lumen, vessel (external elastic membrane (EEM)), and plaque (plaque + media) volumes were calculated. Remodelling was determined by comparing the EEM area at the centre of the lesion with the EEM areas at proximal and distal reference sites. Plaque eccentricity was defined as the thinnest plaque diameter to the thickest plaque diameter ratio. Plaque composition was characterised as soft, mixed, or dense. RESULTS: All volumetric IVUS changes were similar in the two groups. Pre-intervention remodelling remained uninfluenced after direct stenting, but was neutralised after predilatation stenting. Eccentric lesions responded to intervention by a greater luminal gain owing to greater vessel expansion in direct stenting. Plaque composition influenced luminal gain in direct stenting, the gain being greatest in the softest plaques; in predilatation stenting, luminal gain was equivalent but vessel expansion was greater for "dense" plaque and plaque reduction greater for "soft" plaque. CONCLUSIONS: In non-calcified lesions, the mechanisms of lumen enlargement after direct or predilatation stenting are significantly influenced by atherosclerotic remodelling, plaque eccentricity, and plaque composition.

Comparative efficacy of gamma-irradiation for treatment of in-stent restenosis in saphenous vein graft versus native coronary artery in-stent restenosis: An intravascular ultrasound study.

BACKGROUND: We used serial volumetric (post-irradiation and follow-up) intravascular ultrasound (IVUS) to compare the effectiveness of gamma-irradiation ((192)Ir) in saphenous vein graft (SVG) versus native coronary artery in-stent restenosis (ISR). METHODS AND RESULTS: The study population consisted of 47 patients with native coronary artery ISR from WRIST (Washington Radiation for In-Stent Restenosis Trial) and 31 patients with SVG ISR (12 from the WRIST and 19 from SVGWRIST). After irradiation and at 6-month follow-up, stent, lumen, and intimal hyperplasia (IH, stent minus lumen) areas were measured every 1 mm. ISR length was similar in the 2 groups (29+/-12 versus 29+/-14 mm, P=0.9). Post-intervention measurements of stent (280+/-154 versus 324+/-270 mm(3), P=0.4), lumen (184+/-91 versus 214+/-172 mm(3), P=0.3), and IH (96+/-77 versus 109+/-119 mm(3), P=0.5) volumes were similar in the 2 groups. The post-intervention minimum lumen cross sectional areas tended to be smaller in native artery ISR lesions (4.7+/-1.7 versus 5.4+/-1.6 mm(2), P=0.11). During follow-up, there was a slight increase in IH volume (9+/-38 mm(3)) in native artery ISR lesions and a slight decrease in IH volume in SVG ISR lesions (-9+/-32 mm(3), P=0.0463). There was also a slight decrease in minimum lumen area in the native artery ISR lesions versus a slight increase in minimum lumen area in the SVG ISR lesions (-0.8+/-1.7 versus 0.2+/-1.1, P=0.0087). As a result, the follow-up minimum lumen area in native artery lesions was smaller than in SVG ISR lesions (4.1+/-2.1 mm(2) versus 5.6+/-2.2 mm(2), P=0.0067). CONCLUSION: gamma-Irradiation with (192)Ir brachytherapy appears to be as effective in SVGs as it is in native artery ISR lesions.

The contribution of "mechanical" problems to in-stent restenosis: An intravascular ultrasonographic analysis of 1090 consecutive in-stent restenosis lesions.

OBJECTIVES: Serial intravascular ultrasonographic (IVUS) studies have shown that in-stent restenosis is the result of intimal hyperplasia (IH). However, routine preintervention IVUS imaging has suggested that many restenotic stents were inadequately deployed. The purpose of this IVUS study was to determine the incidence of mechanical problems contributing to in-stent restenosis (ISR). METHODS: Between April 1994 and June 2000, 1090 patients with ISR were treated at the Washington Hospital Center. All underwent preintervention IVUS imaging. IVUS measurements included proximal and distal reference lumen areas and diameters; stent, minimum lumen, and IH (stent minus lumen) areas; and IH burden (IH/stent area). RESULTS: In 49 ISR lesions (4.5%), there were morphologic findings that contributed to the restenosis. These were termed mechanical complications. Examples include (1) missing the lesion (eg, an aorto-ostial stenosis), (2) stent "crush," and (3) having the stent stripped off the balloon during the implantation procedure. Excluding mechanical complications, stent underexpansion was common. In 20% of the ISR cases the stents had a cross-sectional area (CSA) at the site of the lesion <80% of the average reference lumen area. Twenty percent of lesions had a minimum stent area <5.0 mm(2) and an additional 18% had a minimum stent area of 5.0 to 6.0 mm(2). Twenty-four percent of lesions had an IH burden <60%. CONCLUSION: Mechanical problems related to stent deployment procedures contribute to a significant minority of ISR lesions (approximately 25%).

An intravascular ultrasound classification of angiographic coronary artery aneurysms.

The purpose of this study was to use intravascular ultrasound (IVUS) to clarify the morphology of coronary aneurysms diagnosed by angiography. Seventy-seven consecutive patients with an aneurysmal dilatation in a native coronary artery diagnosed by angiography (defined as a lesion lumen diameter 25% larger than reference) were evaluated by IVUS. IVUS true aneurysms were defined as having an intact vessel wall and a maximum lumen area 50% larger than proximal reference. IVUS pseudoaneurysms had a loss of vessel wall integrity and damage to adventitia or perivascular tissue. Complex plaques were lesions with ruptured plaque or spontaneous or unhealed dissection. Aneurysmal dilatation and reference segments were assessed using standard IVUS quantitative techniques. Twenty-one lesions (27%) were classified as true aneurysms, 3 (4%) were classified as pseudoaneurysms, 12 (16%) were complex plaques, and the other 41 (53%) were normal arterial segments adjacent to > or =1 stenosis. The maximum lumen area within the aneurysmal segment was largest for pseudoaneurysm (35.1 +/- 10.4 mm(2)), 22.1 +/- 9.9 mm(2) for true aneurysm, and similar for complex plaques (11.2 +/- 3.5 mm(2)) and normal segments with adjacent stenoses (13.8 +/- 6.4 mm(2)): analysis of variance, p <0.0001. Only one third of angiographically diagnosed aneurysms had the IVUS appearance of a true or pseudoaneurysm. Instead, most angiographically diagnosed aneurysms had the morphology of complex plaques or normal segments with adjacent stenoses.

Vascular complications after percutaneous coronary interventions following hemostasis with manual compression versus arteriotomy closure devices.

OBJECTIVES: We evaluated the vascular complications after hemostasis with arteriotomy closure devices (ACD) versus manual compression after percutaneous coronary interventions (PCI). BACKGROUND: Previous clinical studies have indicated that ACD can be used for achievement of hemostasis and early ambulation after PCI. This study investigated the safety of ACD in achieving hemostasis after PCI compared with manual compression in a large cohort of consecutive patients. METHODS: A total of 5,093 patients were followed after PCI was performed with the transfemoral approach. Univariate and multivariate analysis were used to identify the predictors of vascular complications with ACD (n = 516) or with manual compression (n = 5,892) as a hemostasis option after sheath removal. RESULTS: The use of ACD was associated with a more frequent occurrence of hematoma compared with manual compression (9.3 vs. 5.1%, p < 0.001). There was also a higher rate of significant hematocrit drop (>15%) with ACD versus manual compression (5.2% vs. 2.5%, p < 0.001). Similar rates of pseudoaneurysm and arteriovenous fistulae were noted with either hemostasis technique. Vascular surgical repair at the access site was required more often with ACD versus manual compression (2.5 vs. 1.5%, p = 0.03). CONCLUSIONS: In this early experience with ACD after PCI, their use was associated with higher vascular complication rates than hemostasis with manual compression.

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.

Are we making progress with percutaneous saphenous vein graft treatment? A comparison of 1990 to 1994 and 1995 to 1998 results.

OBJECTIVES: We sought to determine whether strategies to reduce procedural distal embolization and late repeat revascularization have resulted in more favorable outcomes after saphenous vein graft (SVG) angioplasty. BACKGROUND: Angioplasty of SVG lesions has been associated with frequent procedural and late cardiac events. Therefore, evolving strategies have been attempted to improve outcomes after SVG angioplasty. METHODS: We compared our earlier experience (1990 to 1994) of 1,055 patients with 1,412 SVG lesions with a recent group (1995 to 1998) of 964 patients with 1,315 lesions. RESULTS: Baseline characteristics were similar between the groups. However, there were significantly more unfavorable lesion characteristics (older, longer and significantly more degenerated SVGs) in the recent series. Between the two periods, there was decreased use ofatheroablative devices, whereas stent use increased. The procedural success rates (96.6% vs. 96.1%) were similar. However, one-year outcome (event-free survival) was significantly improved in the more recent experience (70.7% vs. 59.1%, p < 0.0001), especially late mortality (6.1% vs. 11.3%, p < 0.0001). Multivariate analysis showed stent use to be the only protective variable for both periods. CONCLUSIONS: This study shows that despite higher risk lesions, strategies to reduce distal embolization have maintained high procedural success. Late cardiac events, including mortality, have also been substantially reduced.

Prognostic value of cardiac troponin I re-elevation following percutaneous coronary intervention in high-risk patients with acute coronary syndromes.

Troponin I is a predictive marker of short- and intermediate-term adverse cardiac events in patients with acute coronary syndromes (ACS). These high-risk patients may benefit from early percutaneous coronary intervention. However, whether additional myocardial injury, defined as postprocedural troponin I elevation, may be associated with adverse short- and intermediate-term outcomes has not been fully explored. Accordingly, we studied 132 consecutive patients with non-ST-elevation ACS (62% with non-Q-wave myocardial infarction) and elevated troponin I levels at admission (>0.15 ng/ml) who underwent percutaneous coronary intervention > or =48 hours after admission. Troponin I levels were routinely measured at 6 and 18 to 24 hours after intervention and patients were stratified according to the presence or absence of troponin I re-elevation, defined as postprocedural troponin I levels >1 times the admission levels. In-hospital and cumulative 6-month clinical outcomes were compared between groups. Patients with troponin I re-elevation (n = 51) were older (68 +/- 13 vs 64 +/- 12 years, p = 0.05) and had experienced prior myocardial infarction more frequently (92.5 vs 82.1, p = 0.09), but otherwise had similar baseline clinical characteristics. Patients with troponin I re-elevation had significantly higher in-hospital mortality (9.8% vs 0%, p = 0.016) and a higher 6-month cumulative death rate (24% vs 3.7%, p = 0.001). There was a trend for an increased 6-month myocardial infarction rate in patients with troponin I re-elevation (13.7% vs 3.7%, p = 0.11) and target vessel revascularization was similar between groups (16.7% vs 17.4%, p = 0.92). By multivariate analysis, troponin I re-elevation (odds ratio [OR] 6.2, p = 0.011) and diabetes mellitus (OR 5.7, p = 0.014) were the strongest independent predictors for increased 6-month cumulative mortality, whereas creatine kinase MB-fraction re-elevation had no prognostic value. We conclude that troponin I re-elevation after percutaneous coronary intervention in high-risk patients with ACS is associated with a substantial increase in mortality and reduced event-free survival at 6-month follow-up.

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.

Intravascular ultrasound assessment of the stenoses location and morphology in the left main coronary artery in relation to anatomic left main length.

Eighty-seven left main stenoses were evaluated by angiography and intravascular ultrasound. Intravascular ultrasound analysis included left main length (bifurcation to ostium), stenosis location, stenosis length, stenosis external elastic membrane, lumen, plaque & media cross-sectional area (CSA), plaque burden (plaque & media/external elastic membrane CSA), calcium arc, calcium length, eccentricity, and remodeling index (stenosis/reference external elastic membrane CSA). Long anatomic left main arteries (length > or =10 mm, n = 43) were compared with short anatomic left main arteries (length <10 mm, n = 44) regarding stenosis location. Ostial (proximal third of left main artery) (n = 32) and nonostial (midthird and distal third) stenoses (n = 55) were compared regarding stenosis morphology. Short anatomic left main arteries developed stenoses more frequently near the ostium (ostium 55%, bifurcation 38%). Conversely, long anatomic left main arteries developed stenoses more frequently near the bifurcation (ostium 18%, bifurcation 77%, p = 0.001). Ostial left main stenoses were more common in women (44% vs 20%, p = 0.02), had larger lumen area (6.2 +/- 2.2 vs 4.6 +/- 2.3 mm(2), p = 0.002), less plaque burden (62 +/- 15% vs 80 +/- 9%, p <0.0001), less calcification (arc = 78 +/- 65 degrees vs 195 +/- 101 degrees, p <0.0001), and more negative remodeling (remodeling index = 0.87 +/- 0.19 vs 1.01 +/- 0.21, p = 0.005) than nonostial left main stenoses. Most ostial left main stenoses were categorized as eccentric (97% vs 76%, p = 0.01). Short and long left main arteries develop stenoses at different locations. Stenosis morphology was significantly different in these 2 locations.

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.

Acute renal failure requiring dialysis after percutaneous coronary interventions.

Acute renal failure requiring dialysis is a rare but serious complication after percutaneous coronary interventions (PCI), associated with high in-hospital mortality and poor long-term survival. We have analyzed the incidence, resource utilization, short- and long-term outcomes, and predictors of dialysis after percutaneous coronary interventions. We studied 51 consecutive patients who were not on dialysis on admission and developed acute renal failure that required in-hospital dialysis after PCI in comparison to the 7,690 patients who did not require dialysis after PCI. Patients who required dialysis were older, with a higher incidence of hypertension, diabetes, prior bypass surgery, chronic renal failure, and a significantly lower left ventricular ejection fraction. Despite similar angiographic success, these patients had a higher incidence of in-hospital mortality (27.5% vs. 1.0%, P < 0.0001), non-Q-wave myocardial infarction (45.7% vs. 14.6%, P < 0.0001), vascular and bleeding complications, and longer hospitalization. At 1-year follow-up, mortality (54.5% vs. 6.4%, P < 0.0001), myocardial infarction (4.5% vs. 1.6%, P = 0.006), and event-free survival (38.6% vs. 72.0%, P < 0.0001) were significantly worse in patients who required dialysis compared to patients who did not. Multivariate analysis revealed in-hospital dialysis and an increase in baseline serum creatinine levels as the most important predictors of in-hospital and long-term mortality. Thus, acute renal failure that requires dialysis after percutaneous coronary interventions is associated with very high in-hospital and 1-year mortality rates and a dramatic increase in hospital resource utilization.

Treatment of focal in-stent restenosis with balloon angioplasty alone versus stenting: Short- and long-term results.

BACKGROUND: Although both percutaneous transluminal coronary angioplasty (PTCA) and additional stenting can be used for the treatment for focal in-stent restenosis (ISR), no large-scale comparative data on the clinical outcomes after these interventional procedures have been reported. METHODS: In the current study we compared the in-hospital and long-term clinical results of PTCA alone (n = 266 patients, n = 364 lesions) versus stenting (n = 135 patients, n = 161 lesions) for the treatment of focal ISR, defined as a lesion length less than or equal to 10 mm. RESULTS: There were significantly more diabetic patients in the PTCA group than in the stent group (36% vs 26%, P =.04), but other baseline characteristics were similar. Lesion length and preprocedure minimal lumen diameter (MLD) were also similar in the two groups, but the stent group had a larger reference vessel diameter (3.40 +/- 0.73 mm vs 2.99 +/- 0.68 mm, P <.001). Stenting achieved a larger postprocedure MLD than PTCA did (2.95 +/- 0.95 mm vs 2.23 +/- 0.60 mm, P <.001) and a smaller residual diameter stenosis (11% +/- 15% vs 23% +/- 16%, P =.04). Angiographic success was achieved in all cases. The rate of death/Q-wave infarction of urgent revascularization was higher with PTCA than with stent (5.6% vs 0.7%, P =.02). Postprocedure creatine kinase myocardial band enzyme elevation >5 times normal was more frequent with stent (18.5% vs 9.7%, P =.05). At 1 year the two interventional strategies had similar cumulative mortality (4.6% PTCA vs 5.1% stent, P not significant) and target lesion revascularization rate (24.6% PTCA vs 26.5% stent, P not significant). By multivariate analysis, the sole predictor of target lesion revascularization was diabetes (odds ratio 2.4, 95% confidence intervals 1.2-4.7, P =.01). CONCLUSION: Repeat stenting for the treatment of focal ISR had a higher postprocedure creatine kinase myocardial band elevation rate and similar long-term clinical results compared with PTCA alone.