In vivo assessment of stent expansion and recoil in normal porcine coronary arteries: differential outcome by stent design.

BACKGROUND: Despite the routine use of high pressure, coronary stents generally fail to achieve a cross-sectional area (CSA) >60% to 80% of the nominal CSA of their dilating balloon. The extent to which incomplete balloon expansion and postdeflation stent recoil contribute to this failure has not been fully evaluated. METHODS AND RESULTS: Thirty-two stents (8 Gianturco-Roubin II, 8 Palmaz-Schatz, 8 MultiLink, and 8 NIR) were deployed in nondiseased coronary arteries of 8 Yorkshire pigs. All stents were then expanded according to 1 of 3 balloon strategies: appropriately sized compliant balloons, oversized compliant balloons, or oversized noncompliant balloons. Continuous ultrasound imaging was performed during stepwise balloon inflation and deflation, with an 0.018-in imaging core positioned within the guidewire lumen of the balloon. In these normal arteries, balloon underexpansion relative to the nominal size was not observed. After balloon deflation, however, all stents showed significant recoil from their maximum inflated CSA. Recoil was significantly greater for the coil Gianturco-Roubin II stent (30% CSA) than for the 3 slotted-tube stent designs (15% to 17% CSA). CONCLUSIONS: In normal, compliant coronary arteries, stent recoil is the predominant mechanism by which stents fail to achieve the nominal CSA of their dilating balloon. The magnitude of this in vivo stent recoil is significantly greater than reported from bench testing and varies with stent design (coil versus slotted tube). Postdilatation strategies that result in controlled stent overexpansion are needed to overcome this recoil phenomenon and result in a final stent CSA that approximates the reference artery CSA.

Stent thrombosis in the modern era: a pooled analysis of multicenter coronary stent clinical trials.

BACKGROUND: There are limited studies of stent thrombosis in the modern era of second-generation stents, high-pressure deployment, and current antithrombotic regimens. METHODS AND RESULTS: Six recently completed coronary stent trials and associated nonrandomized registries that enrolled 6186 patients (6219 treated vessels) treated with >/=1 coronary stent followed by antiplatelet therapy with aspirin and ticlopidine were pooled for this analysis. Within 30 days, clinical stent thrombosis developed in 53 patients (0.9%). The variables most significantly associated with the probability of stent thrombosis were persistent dissection NHLBI grade B or higher after stenting (OR, 3.7; 95% CI, 1.9 to 7.7), total stent length (OR, 1.3; 95% CI, 1.2 to 1.5 per 10 mm), and final minimal lumen diameter within the stent (OR, 0.4; 95% CI, 0.2 to 0.7 per 1 mm). Stent thrombosis was documented by angiography in 45 patients (0.7%). Clinical consequences of angiographic stent thrombosis included 64.4% incidence of death or myocardial infarction at the time of stent thrombosis and 8.9% 6-month mortality. CONCLUSIONS: Stent thrombosis occurred in <1.0% of patients undergoing stenting of native coronary artery lesions and receiving routine antiplatelet therapy with aspirin plus ticlopidine. Procedure-related variables of persistent dissection, total stent length, and final lumen diameter were significantly associated with the probability of stent thrombosis. Continued efforts to eliminate this complication are warranted given the serious clinical consequences.

Short- and intermediate-term clinical outcomes from direct myocardial laser revascularization guided by biosense left ventricular electromechanical mapping.

BACKGROUND: Direct myocardial revascularization (DMR) has been examined as an alternative treatment for patients with chronic refractory myocardial ischemic syndromes who are not candidates for conventional coronary revascularization. Methods and Results-We used left ventricular electromagnetic guidance in 77 patients with chronic refractory angina (56 men, mean age 61+/-11 years, ejection fraction 0.48+/-0.11) to perform percutaneous DMR with an Ho:YAG laser at 2 J/pulse. Procedural success (laser channels placed in prespecified target zones) was achieved in 76 of 77 patients with an average of 26+/-10 channels (range 11 to 50 channels). The rate of major in-hospital cardiac adverse events was 2.6%, with no deaths or emergency operations, 1 patient with postprocedural pericardiocentesis, and 1 patient with minor embolic stroke. The rate of out-of-hospital adverse cardiac events (up to 6 months) was 2.6%, with 1 patient with myocardial infarction and 1 patient with stroke. Exercise duration after DMR increased from 387+/-179 to 454+/-166 seconds at 1 month and to 479+/-161 seconds at 6 months (P=0.0001). The time to onset of angina increased from 293+/-167 to 377+/-176 seconds at 1 month and to 414+/-169 seconds at 6 months (P=0.0001). Importantly, the time to ST-segment depression (>/=1 mm) also increased from 327+/-178 to 400+/-172 seconds at 1 month and to 436+/-175 seconds at 6 months (P=0.001). Angina (Canadian Cardiovascular Society classification) improved from 3.3+/-0.5 to 2.0+/-1.2 at 6 months (P<0.001). Nuclear perfusion imaging studies with a dual-isotope technique, however, showed no significant improvements at 1 or 6 months. CONCLUSIONS: Percutaneous DMR guided by left ventricular mapping is feasible and safe and reveals improved angina and prolonged exercise duration for up to a 6-month follow-up.

Final results of the Can Routine Ultrasound Influence Stent Expansion (CRUISE) study.

BACKGROUND: Intravascular ultrasound (IVUS) can assess stent geometry more accurately than angiography. Several studies have demonstrated that the degree of stent expansion as measured by IVUS directly correlated to clinical outcome. However, it is unclear if routine ultrasound guidance of stent implantation improves clinical outcome as compared with angiographic guidance alone. METHODS AND RESULTS: The CRUISE (Can Routine Ultrasound Influence Stent Expansion) study, a multicenter study IVUS substudy of the Stent Anti-thrombotic Regimen Study, was designed to assess the impact of IVUS on stent deployment in the high-pressure era. Nine centers were prospectively assigned to stent deployment with the use of ultrasound guidance and 7 centers to angiographic guidance alone with documentary (blinded) IVUS at the conclusion of the procedure. A total of 525 patients were enrolled with completed quantitative coronary angiography, quantitative coronary ultrasound, and clinical events adjudicated at 9 months for 499 patients. The IVUS-guided group had a larger minimal lumen diameter (2.9+/-0.4 versus 2.7+/-0. 5 mm, P<0.001) by quantitative coronary angiography and a larger minimal stent area (7.78+/-1.72 versus 7.06+/-2.13 mm(2), P<0.001) by quantitative coronary ultrasound. Target vessel revascularization, defined as clinically driven repeat interventional or surgical therapy of the index vessel at 9 month-follow-up, occurred significantly less frequently in the IVUS-guided group (8.5% versus 15.3%, P<0.05; relative reduction of 44%). CONCLUSIONS: These data suggest that ultrasound guidance of stent implantation may result in more effective stent expansion compared with angiographic guidance alone.

Generalized model of restenosis after conventional balloon angioplasty, stenting and directional atherectomy.

OBJECTIVES: This study was designed to extend the results of a quantitative model originally developed for restenosis after stenting or atherectomy to include restenosis after conventional balloon angioplasty. BACKGROUND: We have previously described a continuous regression model that explains late (6-month) lumen narrowing as the difference between the immediate gain and the subsequent normally distributed late loss in lumen diameter after Palmaz-Schatz stenting or directional atherectomy. METHODS: Lumen diameter was measured immediately before and after coronary intervention on 524 consecutive lesions including those treated by Palmaz-Schatz stenting (102), directional atherectomy (134) and conventional balloon angioplasty (288). Of these lesions, 475 (91%) underwent follow-up angiography 3 to 6 months after treatment. The immediate increase in lumen diameter produced by the intervention (immediate gain) and the subsequent reduction in lumen diameter between the time of intervention to follow-up angiography (late loss) were examined. Association between demographic or angiographic variables and continuous measures of restenosis (late lumen diameter or late percent stenosis) was tested with linear regression techniques; a traditional binary measure of restenosis (late diameter stenosis > or = 50%) was evaluated with logistic regression analysis. RESULTS: Regression models relating late lumen diameter to the immediate lumen result were successfully fitted to all segments studied. According to these models, three indexes of restenosis (late lumen diameter, late percent stenosis and binary restenosis) were found to depend solely on the immediate lumen diameter after the procedure and the immediate residual percent stenosis, but not on the specific intervention used. Moreover, the late loss in lumen diameter was found to vary directly with the immediate gain provided by an intervention, and the "loss index" (a measure that corrects for differences in immediate gain) was uniform among all three interventions. CONCLUSIONS: The quantitative model originally developed for restenosis after stenting or atherectomy may thus be generalized to include conventional balloon angioplasty. It shows that the apparent differences in restenosis among the three interventions studied are due solely to differences in the immediate result provided and not to differences in the behavior of subsequent late loss. Moreover, although the late loss in lumen diameter was found to correlate with differences in the immediate gain provided by an intervention, the "loss index" (a measure that corrects for differences in acute gain) was uniform across all three interventions. It is thus the immediate result (and not the procedure used to obtain that result) that determines late outcome after coronary intervention.

Coronary angioplasty under the prospective payment system: the need for a severity-adjusted payment scheme.

To evaluate the adequacy of Diagnosis Related Group prospective payment for percutaneous transluminal coronary angioplasty, the clinical characteristics, length of stay and hospital charges of all patients undergoing this procedure at Boston's Beth Israel Hospital during a 100 day period were examined. Of 113 such patients, the 61 patients in whom nonelective dilation was performed for unstable or postinfarction angina had a significantly greater length of stay and total hospital charge (10 +/- 6 days and $14,700 +/- $7,400, respectively) than did the 52 patients in whom elective dilation was performed (6 +/- 5 days and $8,500 +/- $7,700, respectively, p less than 0.0001). Under the current prospective payment system, however, these two groups of patients would have been placed in the same Diagnosis Related Group, and would have thus commanded equal institutional reimbursement. One potential revision of the payment system is presented to help to deal with this disparity.

Clinical experience with the Palmaz-Schatz coronary stent.

Complications that occurred in 247 patients who underwent successful elective stenting to native coronary arteries with the Palmaz-Schatz balloon expandable stent included subacute thrombosis in 7 patients (2.8%), myocardial infarction in 3 (1.2%), death 3 (1.2%), urgent bypass surgery in 4 (1.6%) and major bleeding events in 24 (9.7%). Angiographic restenosis occurred in 21 (20%) of 103 patients who received a single stent. Subgroup analysis, however, revealed that restenosis of a single stent occurred in 3 (7%) of 45 patients without prior angioplasty compared with 25 (27%) of 91 patients with prior angioplasty. Patients with "suboptimal" angioplasty results (dis-section) who received a single stent seemed to have a higher thrombosis rate perioperatively (4 [4%] of 98), but no higher incidence of restenosis (7 [15%] of 46) than that of the total group of patients who received a single stent. Coronary stenting may be a valuable adjunct to coronary angioplasty in carefully selected patients. Complication rates are similar to those of routine angioplasty; however, angiographic restenosis may be reduced in certain subsets of patients.

Analysis of late lumen narrowing after excimer laser-facilitated coronary angioplasty.

OBJECTIVES: The purpose of this study was to analyze the quantitative angiographic factors affecting restenosis after excimer laser-facilitated coronary angioplasty. BACKGROUND: Restenosis after balloon angioplasty, directional atherectomy and coronary stenting has been analyzed using both dichotomous (> or = 50% diameter stenosis) and continuous (late lumen narrowing) end points, leading to the conclusion that achieving a large lumen diameter at the time of the procedure is associated with a lower risk of angiographic restenosis. METHODS: Quantitative angiographic measurements were made before treatment, after laser angioplasty, after adjunctive balloon angioplasty and at 6-month angiographic follow-up in 168 patients with 179 treated lesions. RESULTS: The immediate increase in lumen diameter (total acute gain 1.45 +/- 0.71 mm [mean +/- SD]) was due to the combination of laser treatment (0.79 +/- 0.61 mm) and subsequent adjunctive balloon angioplasty (0.66 +/- 0.55 mm). At follow-up, the minimal lumen diameter had decreased (late loss 0.71 +/- 0.84 mm), yielding an overall restenosis rate of 50% (defined dichotomously by > or = 50% diameter stenosis). Multivariable regression analyses showed that restenosis was related to vessel diameter, as well as minimal lumen diameter, achieved immediately after the procedure. CONCLUSIONS: Although the restenosis rates for the small vessels typically treated with excimer laser angioplasty were high, the lowest restenosis rates were seen in large vessels with the largest postprocedural minimal lumen diameters. The goal of this procedure should be to safely achieve the largest lumen possible with the combination of laser treatment and adjunctive balloon dilation.

Long-term (4- to 6-year) outcome of Palmaz-Schatz stenting: paucity of late clinical stent-related problems.

OBJECTIVES: The purpose of this prospective single-center study was to evaluate the longer-term outcome of Palmaz-Schatz stenting in the treatment of native coronary and saphenous vein bypass graft disease. BACKGROUND: The STRESS (Stent Restenosis Study) and BENESTENT (Belgian Netherlands Stent) trials have demonstrated a decrease in both angiographic restenosis and the need for repeat revascularization in the 1st year for vessels treated by stenting rather than balloon angioplasty. Longer-term (1 to 5 years) clinical results of Palmaz-Schatz stenting are not yet well established. Late migration of the stent, metal fatigue, endarteritis and late restenosis have all been proposed as potential late clinical complications of coronary stent implantation. METHODS: The study cohort consisted of 175 consecutive patients who underwent elective placement of 194 Palmaz-Schatz stents in 185 vessels. Clinical events (death, myocardial infarction, recurrent angina or any revascularization) were assessed at 6 weeks, 2, 4 and 6 months, 1 year and yearly thereafter. Clinical follow-up was available on all patients at a mean +/- SD of 54 +/- 17 months. RESULTS: Angiographic success was achieved in 173 patients (98.9%); angiographic restenosis was observed at 6 months in 26.1% of target sites. The survival rate was 86.7% at 5 years, with a 5-year event-free survival rate decreasing progressively to 50.7%, reflecting primarily repeat revascularization procedures (41.2% at 5 years). However, the rate of repeat revascularization of the treatment site (target site revascularization [TSR]) was 14.4%, 17.7% and 19.8% at 1, 3 and 5 years, respectively, with late (> 1 year) TSR driven by in-stent restenosis in only 3 patients (1.7%). Rates of both 5-year survival (70.5% vs. 93.4%) and event-free survival (21.1% vs. 63.3%) were lower for patients who underwent saphenous vein graft (SVG) stenting than for those with native coronary artery stenting. However, 5-year TSR rates were similar for SVGs (21.9%) and native vessels (19.2%), indicating that the higher incidence of repeat revascularization for SVGs was due to an increase in non-TSR, driven by progressive disease at other sites. CONCLUSIONS: The long-term outcome of stenting shows stability of the treated lesion, with only a slight increase in TSR between 2 and 5 years (17.1% to 19.8%). The progressive increase in repeat revascularization over that period (24% to 41%) and most ongoing late events can be attributed to the progression of coronary disease at other sites, rather than to late deterioration of the stent result itself. Such non-TSR events account for the majority of clinical events in the patients who underwent SVG stenting.

Current complications of diagnostic and therapeutic cardiac catheterization.

Data from 2,883 cardiac catheterizations performed during an 18 month period (from July 1986 through December 1987) were analyzed to assess the current complication profile of diagnostic and therapeutic procedures. Procedures performed during the study period included 1,609 diagnostic catheterizations, 933 percutaneous transluminal coronary angioplasties and 199 percutaneous balloon valvuloplasties. Overall, the mortality rate was 0.28% but ranged from 0.12% for diagnostic catheterizations to 0.3% for coronary angioplasty and 1.5% for balloon valvuloplasty. Emergency cardiac surgery was required in 12 angioplasty patients (1.2%). Cardiac perforation occurred in seven patients (0.2%), of whom six were undergoing valvuloplasty, and five (2.5% of valvuloplasty attempts) required emergency surgery for correction. Local vascular complications requiring operative repair occurred in 1.9% of patients overall, ranging from 1.6% for diagnostic catheterization to 1.5% for angioplasty and 7.5% for valvuloplasty. Although the complication rates for diagnostic catheterization compare favorably with those of previous multicenter registries, current overall complication rates are significantly higher because of the performance of therapeutic procedures with greater intrinsic risk and the inclusion of increasingly aged and acutely ill or unstable patients.

Transcatheter closure of coronary artery fistulas.

Transcatheter closure of a coronary artery fistula was undertaken in nine patients. There were three fistulas from the left circumflex coronary artery to the coronary sinus, three from the left anterior descending coronary artery to the right ventricular apex, two from the right coronary artery to the superior vena cava/right atrial junction and one fistula from the left circumflex artery to the pulmonary artery. The fistula was closed with Gianturco coils in six patients, a double-umbrella device in two and a combination of an umbrella and coils in one patient. All fistulas are completely occluded. Complications consisted of migration of two coils, one of which was retrieved, and a transient junctional tachycardia in one patient. In an additional three patients with multiple coronary artery fistulas, transcatheter occlusion was not attempted.

Economics of elective coronary revascularization. Comparison of costs and charges for conventional angioplasty, directional atherectomy, stenting and bypass surgery.

OBJECTIVES: This study was designed to evaluate more closely the true in-hospital costs of elective revascularization by directional coronary atherectomy and intracoronary stenting and to compare these costs with those of the traditional revascularization alternatives (i.e., conventional balloon angioplasty and coronary artery bypass surgery). BACKGROUND: Previous studies have suggested that total hospital charges for directional coronary atherectomy or intracoronary stenting are significantly higher than those for conventional angioplasty. However, hospital charges do not necessarily reflect true economic costs, and their use may provide misleading data with regard to cost-effectiveness. METHODS: We analyzed in-hospital charges from the itemized hospital accounts of 300 patients undergoing elective angioplasty, directional atherectomy, Palmaz-Schatz coronary stenting or bypass surgery between January 1, 1990 and December 31, 1991. Costs were then derived by adjusting itemized patient accounts for department-specific cost/charge ratios. Catheterization laboratory costs were based on actual resource consumption, and daily room costs were adjusted for the intensity of nursing services provided. RESULTS: Length of hospital stay was similar for atherectomy (2.3 +/- 1.5 days) and conventional angioplasty (2.6 +/- 1.7 days) but significantly longer for stenting (5.5 +/- 2.6 days, p < 0.05). Total costs were also significantly higher for coronary stenting ($7,878 +/- $3,270, median $6,699, p < 0.05) than for angioplasty ($5,396 +/- $2,829, median $4,753) or atherectomy ($5,726 +/- $2,716, median $4,986). However, length of stay, resource consumption (laboratory and radiologic testing, drugs, blood products, for example) and total costs for bypass surgery were still greater than for any of the percutaneous interventional procedures. CONCLUSIONS: In contrast to previous studies utilizing only hospital charges, the in-hospital costs of angioplasty and directional coronary atherectomy were similar. Although the cost of coronary stenting was approximately $2,500 higher than that of conventional angioplasty, the magnitude of this difference was smaller than the $6,300 increment previously suggested on the basis of analysis of hospital charges. These findings reflect the inherent discrepancies between cost-based and charge-based methodologies and may have important implications for future studies evaluating the relative cost-effectiveness of newer coronary interventions.

Mechanisms of restenosis and redilation within coronary stents--quantitative angiographic assessment.

OBJECTIVES: This study was designed to assess the relative contributions of intimal hyperplasia and stent compression to the lumen narrowing seen after intracoronary stenting and to determine whether the lumen enlargement produced by angioplasty of in-stent restenosis results primarily from compression or extrusion of intimal hyperplasia through the stent or from additional stent expansion. BACKGROUND: Palmaz-Schatz stent placement outwardly displaces plaque and eliminates elastic vessel recoil to provide a large and smooth lumen. Some degree of late lumen narrowing occurs within each stent and causes significant restenosis (> or = 50% stenosis) in 25% to 30% of treated lesions. It has not been clear, however, whether this narrowing results from stent compression (crush) or from in-stent intimal hyperplasia. Because the Palmaz-Schatz stent has a distinct radiographic shadow, it is possible to determine the late diameter of both the stent and the enclosed vessel lumen to assess the relative contributions of these two processes. METHODS: From cineangiograms, initial (after stenting) and late (follow-up) lumen and stent diameters were examined in 55 patients (59 stents, group I) who had both immediate and 6-month (192 +/- 117 days) angiography. Lumen and stent diameter were also examined before and after dilation in 30 patients (30 stents, group II) who underwent angioplasty of severe in-stent restenosis. RESULTS: Late loss in minimal lumen diameter was 0.99 +/- 0.87 mm for group I despite only a slight (0.03 +/- 0.23-mm) reduction in the corresponding stent diameter. After redilation for in-stent restenosis, the acute gain in minimal lumen diameter was 1.51 +/- 0.82 mm for group II, again without appreciable increase (0.06 +/- 0.20 mm) in stent diameter. CONCLUSIONS: Restenosis after intracoronary Palmaz-Schatz stenting appears to be due predominantly to lumen encroachment by intimal hyperplasia within the stent, with minimal contribution of stent compression. Lumen enlargement after coronary angioplasty of in-stent restenosis appears to be due primarily to compression or extrusion of intimal hyperplasia through the stent, or both, rather than to further stent expansion.

Selective versus routine predischarge coronary arteriography after therapy with recombinant tissue-type plasminogen activator, heparin and aspirin for acute myocardial infarction. TIMI II Investigators.

To ascertain whether predischarge arteriography is beneficial in patients with acute myocardial infarction treated with recombinant tissue-type plasminogen activator (rt-PA), heparin and aspirin, the outcome of 197 patients in the Thrombolysis in Myocardial Infarction (TIMI) IIA study assigned to conservative management and routine predischarge coronary arteriography (routine catheterization group) was compared with the outcome of 1,461 patients from the TIMI IIB study assigned to conservative management without routine coronary arteriography unless ischemia recurred spontaneously or on predischarge exercise testing (selective catheterization group). The two groups were similar with regard to important baseline variables. During the initial hospital stay, coronary arteriography was performed in 93.9% of the routine catheterization group and 34.7% of the selective catheterization group (p less than 0.001), but the frequency of coronary revascularization (angioplasty or coronary artery bypass surgery) was similar in the two groups (24.4% versus 20.7%, p = NS). Coronary arteriograms showed a predominance of zero or one vessel disease (stenosis greater than or equal to 60%) in both groups (routine catheterization group 73.1%, selective catheterization group 61.3%). During the 1st year after infarction, rehospitalization for cardiac reasons and the interim performance of coronary arteriography were more common in the selective catheterization group (37.9% versus 27.6%, p = 0.007 and 28.6% versus 11.6%, p less than 0.001, respectively); however, the interim rates of death, nonfatal reinfarction and performance of coronary revascularization procedures were similar. At the end of 1 year, coronary arteriography had been performed one or more times in 98.9% of the routine catheterization group and 59.4% of the selective catheterization group (p less than 0.001), whereas death and nonfatal reinfarction had occurred in 10.2% versus 7.0% (p = 0.10) and 8.6% versus 9.0% (p = 0.87), respectively. Because the selective coronary arteriography policy exposes about 40% fewer patients to the small but finite risks and inconvenience of the procedure without compromising the 1 year survival or reinfarction rates, it seems to be an appropriate management strategy.

Laser balloon angioplasty: clinical, angiographic and histologic results.

Laser balloon angioplasty combines conventional coronary angioplasty with laser energy to transiently heat vascular tissue. Laser balloon angioplasty, was performed in 21 patients (aged 56 +/- 13 years), including 10 patients treated urgently after acute failure of conventional angioplasty and 11 patients treated with elective laser balloon angioplasty. Immediately after conventional angioplasty, laser doses (1 to 10 doses of 205 to 380 J each) were delivered during inflation of the laser balloon to a pressure of 4 atm. Seven (70%) of 10 patients with acute failure of conventional angioplasty were successfully treated with laser balloon angioplasty, but 3 (30%) were unsuccessfully treated with the laser procedure and required emergency coronary artery bypass surgery. In all three failures, the 3 mm laser balloon angioplasty catheter was not the optimal size for the vessel. In the 11 patients treated with elective laser balloon angioplasty (reference diameter 2.94 +/- 0.22 mm), the minimal luminal diameter increased from 0.45 +/- 0.25 to 1.85 +/- 0.46 mm after conventional angioplasty and to 2.44 +/- 0.29 mm after laser balloon angioplasty (p less than 0.001). This corresponded to a decrease in diameter stenosis from 84 +/- 9% before to 35 +/- 16% after conventional angioplasty and to 15 +/- 10% after laser balloon angioplasty (p less than 0.001). There were no instances of myocardial infarction, emergency coronary artery bypass surgery or death and no acute complications related to delivery of laser energy in this group. Follow-up coronary angiography was performed 5.5 +/- 1.1 months after laser balloon angioplasty in 18 patients discharged from the hospital after a successful procedure. Ten patients (56%) had angiographic restenosis, defined as recurrent diameter stenosis greater than 50%. Six patients were subsequently treated by directional coronary atherectomy, which revealed intimal proliferation indistinguishable from that in patients with restenosis after conventional angioplasty. In conclusion, laser balloon angioplasty may be effective in sealing severe coronary dissections and reversing abrupt closure associated with failed conventional angioplasty. After uncomplicated conventional angioplasty, laser balloon angioplasty improves immediate luminal dimensions, but restenosis appears to be mediated by intimal hyperplasia, similar to that seen after conventional angioplasty.

Palmaz-Schatz stenting for treatment of focal vein graft stenosis: immediate results and long-term outcome.

OBJECTIVES: This study aimed to evaluate the effectiveness of Palmaz-Schatz stenting for the treatment of saphenous vein graft stenoses. BACKGROUND: Failure of saphenous vein grafts is a common cause of recurrent ischemia after coronary bypass surgery. A second bypass surgery carries more risk than the initial procedure, and balloon angioplasty of vein grafts has yielded disappointing results. It has been hoped that stenting might offer a better treatment option. METHODS: We examined the results of stent placement in 200 saphenous bypass graft lesions consecutively treated with either coronary (n = 146) or biliary (n = 54) Palmaz-Schatz stents. Immediate outcome and clinical follow-up (median 15.5 months) were examined in all patients. To document angiographic outcome, a second angiography was performed at 3 to 6 months for the first 120 consecutively stented lesions and was successfully obtained for 94 (78%). RESULTS: The mean graft age (+/- SD) was 8.7 +/- 4 years. Stent placement was successful in 197 (98.5%) of 200 lesions, reducing the mean diameter stenosis from 74 +/- 14% to 1 +/- 15%. In 164 procedures, there was one in-hospital death (0.6%), no emergency bypass operations and no Q wave myocardial infarctions. There was one acute stent thrombosis (0.6%) but no subacute thromboses. Vascular repair was required after 14 procedures (8.5%), with transfusion in 23 additional cases (14%). Angiographic restenosis (diameter stenosis > or = 50%) at 3- to 6-month follow-up was 17% (95% confidence interval 9% to 25%). By Kaplan-Meier estimates, however, the 2-year second revascularization rate was 49%, reflecting the predominant revascularization performed to treat progressive disease at other sites because failure at the stented site occurred in only 22% of lesions. CONCLUSIONS: Stenting resulted in excellent immediate and long-term angiographic results in this group of focally diseased, older saphenous vein grafts. Despite the high immediate success and very low (17%) angiographic restenosis rate at 6 months, approximately one half of these patients required further revascularization in the following 2 years, mainly because of disease progression at other sites.

Multivessel Palmaz-Schatz stenting: early results and one-year outcome.

OBJECTIVES: To determine whether the benefits outlined in Background might extend to patients with multivessel disease, we examined the short- and long-term outcome of multivessel Palmaz-Schatz stenting. BACKGROUND: Percutaneous transluminal coronary angioplasty (PTCA) has become the dominant treatment for most patients with single-vessel coronary artery disease and has emerged as an alternative treatment for selected patients with multivessel coronary artery disease. Although multivessel angioplasty has excellent early results and low procedural complication rates, long-term outcome is tempered by the frequent need for repeat revascularization. In patients with single-vessel coronary artery disease, Palmaz-Schatz stenting has been shown to have a higher success rate and a lower restenosis rate than conventional PTCA. METHODS: A total of 103 patients (mean age 64 +/- 11 years, 78 men and 25 women) underwent stenting of 212 vessels (saphenous vein graft [53%], left anterior descending coronary artery [20%], left circumflex artery [12%] and right coronary artery [15%]). In 88 patients (85%), multivessel stenting was performed during the same procedure, whereas the remaining 15 patients (15%) had staged multivessel stenting within 1 week of the index stent. Stenting involved only native coronary arteries in 33 patients and only vein grafts in 51 patients. RESULTS: Angiographic success was achieved in 102 patients (99%). Major complications developed in three patients: one patient died, and two patients had Q wave myocardial infarction, with no emergency coronary artery bypass graft surgery or stent thrombosis. Eleven additional patients (11%) developed non-Q wave myocardial infarction, and nine patients (9%) had local vascular complications requiring surgical repair. Clinical follow-up was available in all patients at a mean of 13 +/- 8 months. At 1 year, survival was 98%, with an event-free survival rate of 80%, reflecting predominantly repeat revascularization (17% overall, with 9% target site revascularization). Multivessel native coronary stenting resulted in a higher event-free survival rate and a lower probability of repeat revascularization than did multivessel saphenous vein graft stenting. CONCLUSIONS: In selected patients, multivessel Palmaz-Schatz stenting is technically feasible and carries both excellent early results and favorable 1-year clinical outcome.

Clinical and angiographic results of balloon-expandable intracoronary stents in right coronary artery stenoses.

Balloon-expandable stents were placed successfully in 35 (95%) of 37 patients whose right coronary artery lesion was believed to have a poor short- or long-term prognosis with conventional balloon angioplasty because of prior restenosis or adverse lesion morphology. Quantitative angiography showed a reduction in stenosis diameter from 83 +/- 14% to 42 +/- 14% after conventional balloon dilation, with a further reduction to -3 +/- 12% after stent placement (p less than 0.001). There were no acute stent thromboses, but one patient (with two stents and unstented distal disease) developed subacute thrombosis on day 8 after self-discontinuation of warfarin and was treated with thrombolytic therapy and redilation. Follow-up angiography was performed at 4 to 6 months in 25 patients, demonstrating restenosis (83 +/- 13%) in 4 (57%) of 7 patients with multiple stents, but only 3 (17%) of 18 patients with a single stent (p less than 0.05). Six of the seven in-stent restenotic lesions were subtotal (80 +/- 12%) and were subjected to repeat conventional balloon angioplasty (postdilation stenosis 13 +/- 21%). The 18 patients without restenosis had a maximal in-stent diameter stenosis of 29 +/- 15%, corresponding to a maximal focal neointimal thickness of 0.68 +/- 0.26 mm within the stented segment. These preliminary results suggest that the Schatz-Palmaz stent may be a useful adjunctive device in the performance of coronary angioplasty.

Long-term results of directional coronary atherectomy: predictors of restenosis.

OBJECTIVES: This study was performed to obtain better understanding of the long-term clinical efficacy of directional coronary atherectomy. BACKGROUND: Although this procedure yields favorable acute results, its acceptance has been limited by the perception that late results (that is, freedom from restenosis) are no better than those of conventional angioplasty. METHODS: A total of 225 atherectomies performed in 190 patients between August 1988 and July 1991 were examined. Minimal lumen diameter of the treated segments was measured on angiograms obtained before, after and 6 months after intervention. RESULTS: Although most lesions (97%) had one or more characteristics predictive of unfavorable short- or long-term results after conventional angioplasty, atherectomy was successful in 205 lesions (91%) with a mean residual stenosis of 7 +/- 16%. After subsequent balloon angioplasty in 16 unsuccessful atherectomy attempts, procedural success was 98%. There were no deaths or Q wave myocardial infarctions, and one patient (0.5%) underwent emergency bypass surgery. Six-month angiographic follow-up was obtained in 77% of the eligible patients. The overall angiographic restenosis rate was 32%. Predictors of a lower restenosis rate included a postprocedure lumen diameter > 3 mm (24% vs. 39%, p = 0.047), serum cholesterol < or = 200 mg/dl (18% vs. 40%, p = 0.018) and recent myocardial infarction (16% vs. 37%, p = 0.034). Life-table analysis showed a 2% mortality rate and a 26% incidence of other events (myocardial infarction, repeat revascularization) within the 1st year. The annual 5% mortality rate and 7% incidence of other events during years 2 and 3 were related in large part to the existence or progression of disease at other locations. CONCLUSIONS: Six-month angiographic follow-up of patients who underwent directional coronary atherectomy during the 1st 3 years of our experience shows an overall restenosis rate of 32%, with lower rates in patients with a postatherectomy lumen diameter > or = 3 mm, cholesterol level < or = 200 mg/dl or a recent myocardial infarction. Few if any events relating to the site of atherectomy developed after the 1st year of follow-up.

Coronary artery stenting in the aged.

OBJECTIVES: The study compared the safety and efficacy of coronary artery stenting in aged and nonaged patients and identified predictors of adverse clinical outcomes. BACKGROUND: Limited data are available on the outcomes of stenting in the aged (> or = 80 years) compared to nonaged patients. METHODS: The study was a pooled analysis of 6,186 patients who underwent coronary artery stenting in six recent multicenter trials. A clinical events committee adjudicated clinical end points, and quantitative angiography was performed by an independent core laboratory. RESULTS: There were 301 (4.9%) aged patients (> or = 80 years). Compared to nonaged patients, aged patients had a higher prevalence of multivessel disease (16.5% vs. 9.6%, p = 0.001), unstable angina (50.8% vs. 42.1%, p = 0.003), moderate to severe target lesion calcification (30.4% vs. 15.3%, p = 0.001) and smaller reference vessel diameter (2.90 mm vs. 2.98 mm, p = 0.004). Procedural success rate (97.4% vs. 98.5%, p = 0.14) was similar in the two groups. In-hospital mortality (1.33% vs. 0.10%, p = 0.001), bleeding complications (4.98% vs. 1.00%, p < 0.001) and one-year mortality (5.65% vs. 1.41%, p < 0.001) were significantly higher for the aged patients. Clinical restenosis was similar for the two groups (11.19% vs. 11.93%, p = 0.78). Advanced age, diabetes, prior myocardial infarction and presence of three-vessel disease were independent predictors of long-term mortality. CONCLUSIONS: Coronary artery stenting can be performed safely in patients > or = 80 years of age, with excellent acute results and a low rate of clinical restenosis, albeit with higher incidences of in-hospital and long-term mortality, and vascular and bleeding complications compared to nonaged patients.