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.

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.

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.

Percutaneous treatment of protected and unprotected left main coronary stenoses with new devices: immediate angiographic results and intermediate-term follow-up.

OBJECTIVES: We sought to evaluate the immediate angiographic results and intermediate-term follow-up after percutaneous treatment of left main coronary stenoses in the new device era. BACKGROUND: Historically, balloon angioplasty of left main coronary stenoses has been associated with high procedural morbidity and poor long-term results. It is not clear whether new devices are more effective in this anatomic setting. METHODS: Between July 1993 and July 1995, we performed initial left main coronary interventions on 46 patients (mean age 67 +/- 12 years, 26% women). Quantitative angiography was available for 42 of 46 interventions, and clinical follow-up was obtained for all patients at 1 month, 6 months and 1 year after initial revascularization. RESULTS: Most interventions (42 of 46) were performed in patients with "protected" coronary stenoses to the left coronary system owing to the presence of one or more patent left main coronary grafts. Seventy-seven percent of screened patients were deemed unsuitable for repeat coronary artery bypass surgery. Procedures performed included stenting in 73% of patients (alone in 30% and after rotational atherectomy in 43%), rotational atherectomy in 58% (alone in 15% and before stenting in 43%), directional atherectomy in 4% and angioplasty alone in 7%. Initial procedural success was achieved in all interventions, with no deaths, myocardial infarctions (creatine kinase, MB fraction > 50 IU/liter) or emergent bypass surgery. Follow-up data to date (median duration 9 months, range 6 to 19) demonstrate a 98% overall survival rate and a 6-month event-free survival rate of 78% (six target vessel revascularizations [TVRs], four non-TVRs). CONCLUSIONS: Treatment of protected left main coronary artery stenoses can be accomplished safely and effectively with new device technology. Intermediate-term follow-up demonstrates an acceptably low rate of death, myocardial infarction or repeat revascularization at 6 months and 1 year.

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.

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.

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.

Angiographic and clinical outcome of intracoronary stenting: immediate and long-term results from a large single-center experience.

OBJECTIVES: The purpose of this study was to determine the immediate and long-term angiographic and clinical results of coronary stenting. BACKGROUND: Although preliminary trials of endovascular stenting have demonstrated promising results, lack of long-term follow-up has limited the critical evaluation of the role of coronary stenting in the treatment of obstructive coronary artery disease. METHODS: A total of 250 procedures using the Palmaz-Schatz stent, performed in 220 patients between June 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: Stent placement was successful in 246 (98%) of 250 lesions, reducing diameter stenosis from 77% to -2.5%. There were no deaths or Q wave myocardial infarctions. One patient (0.4%) required emergency bypass surgery and one (0.4%) developed subacute thrombosis. Femoral vascular complications occurred in 36 patients (16%). Six-month angiographic follow-up was obtained in 91% of eligible patients. The overall angiographic restenosis rate (stenosis greater than or equal to 50%) was 25%. By univariable analysis, the rate of restenosis was significantly higher for stents in the left anterior descending versus the right coronary artery (44% vs. 12%; p = 0.002); in diabetic patients (56% vs. 20%; p = 0.006), and in vessels with post-stent lumen diameter less than 3.31 mm (34% vs. 16%; p = 0.05). Stenting of the left anterior descending artery was the strongest predictor (p = 0.01) of restenosis in a multivariable model. Total survival was 97% and event-free survival (freedom from death, myocardial infarction or revascularization) was 70% at 36 months. CONCLUSIONS: Palmaz-Schatz stents can be placed successfully with a low incidence of major complications. The angiographic restenosis rate was 25%, and 70% of patients remained free of cardiovascular events at 3 years. Diabetes, small postprocedure lumen diameter and stenting of the left anterior descending artery are associated with higher rates of restenosis.

Mechanical debulking versus balloon angioplasty for the treatment of true bifurcation lesions.

OBJECTIVES: The purpose of this study was to compare the immediate angiographic and long-term results of debulking versus balloon angioplasty for treatment of true bifurcation lesions. BACKGROUND: Previous studies have shown true bifurcation lesions to be a high risk morphological subset for percutaneous transluminal coronary angioplasty (PTCA). Although atherectomy devices have been used to treat bifurcation lesions, no studies have compared the outcomes of these alternative treatment modalities. METHODS: Between January 1992 and May 1997, we treated 70 consecutive patients with true bifurcation lesions (defined as a greater than 50% stenosis in both the parent vessel and contiguous side branch) with conventional PTCA (n = 30) or debulking (with rotational or directional atherectomy) plus adjunctive PTCA (n = 40). Paired angiograms were analyzed by quantitative angiography, and clinical follow-up was obtained in all patients. RESULTS: Acute procedural success was 73% in the PTCA group and 97% in the debulking group (p = 0.01). Major in-hospital complications occurred in two patients in the PTCA group and one in the debulking group. Treatment with atherectomy plus PTCA resulted in lower postprocedure residual stenoses than PTCA alone (16+/-15% vs. 33+/-17% in the parent vessel, and 6+/-15% vs. 39+/-22% in the side branch; p < 0.001 for both comparisons). At 1 year follow-up, the incidence of target vessel revascularization (TVR) was 53% in the PTCA group as compared with 28% in the debulking group (p = 0.05). Independent predictors of the need for repeat TVR were side branch diameter >2.3 mm, longer lesion lengths, and treatment with PTCA alone. CONCLUSIONS: For the treatment of true bifurcation lesions, atherectomy with adjunctive PTCA is safe, improves acute angiographic results, and decreases target vessel revascularization compared to PTCA alone. The benefits of debulking for bifurcation lesions were especially seen in lesions involving large side branches.

Quantitative coronary angiographic and intravascular ultrasound assessment of a new nonarticulated stent: report from the Advanced Cardiovascular Systems MultiLink stent pilot study.

OBJECTIVES: The purpose of this study was to evaluate the safety, feasibility, optimal deployment technique and 1-year clinical outcome for the Advanced Cardiovascular Systems (ACS) MultiLink stent. BACKGROUND: Optimal stent deployment assessed by quantitative coronary angiography and intravascular ultrasound (IVUS) is associated with improved clinical outcome. METHODS: Forty-nine consecutive patients with a discrete stenosis in a native coronary artery 3 to 4 mm in diameter were treated with the new, balloon-expandable ACS MultiLink stent. Stent expansion was assessed in all patients using quantitative coronary angiography and serial IVUS imaging after 8-, 12- and 16-atm inflations. Clinical follow-up was obtained at 30 days and 1 year. RESULTS: All 49 patients had successful placement of a MultiLink stent without death, emergency coronary artery bypass graft surgery or Q wave myocardial infarction. After placement of the MultiLink stent, the minimal lumen diameter increased from 1.24 to 2.98 mm (p < 0.001), and diameter stenosis decreased from 61% to 7% (p = 0.001). Minimal lumen cross-sectional area by IVUS increased progressively after 8, 12 and 16 atm (5.6 to 6.8 to 7.4 mm2, respectively, p < 0.001). However, only 64% of stents achieved a lumen/reference area ratio > or = 70%. No adverse clinical events occurred by 30 days, and by 1 year only one patient (2.0%) required revascularization of the stented artery. CONCLUSIONS: Treatment of stenoses in native coronary arteries with the MultiLink stent is associated with a high success rate and a low incidence of adverse events by 1 year, despite the fact that the majority of stents did not meet IVUS-defined criteria for "optimal stenting" derived from first-generation devices.

Bailout and corrective use of Gianturco-Roubin flex stents after percutaneous transluminal coronary angioplasty: operator reports and angiographic core laboratory verification from the National Heart, Lung, and Blood Institute/New Approaches to Coronary Intervention Registry.

OBJECTIVES: We sought to determine the in-hospital clinical outcome and angiographic results of patients prospectively entered into the National Heart, Lung, and Blood Institute/New Approaches to Coronary Intervention (NHLBI/NACI) Registry who received Gianturco-Roubin stents as an unplanned new device. BACKGROUND: Between August 1990 and March 1994, nine centers implanted Gianturco-Roubin flex stents as an unplanned new device in the initial treatment of 350 patients (389 lesions) who were prospectively enrolled in the NHLBI/NACI Registry. METHODS: Patients undergoing implantation of the Gianturco-Roubin flex stent were prospectively entered into the Gianturco-Roubin stent portion of the NHLBI/NACI Registry. Only subjects receiving the Gianturco-Roubin stent as a new device in an unplanned fashion are included. RESULTS: The mean age of the patient group was 61.8 years, and the majority of the patients were men. A history of percutaneous transluminal coronary angioplasty (PTCA) was present in 35.4% of the group, and 16.9% had previous coronary artery bypass graft surgery. Unstable angina was present in 67.7%. Double- or triple-vessel coronary artery disease was present in 55.4%, and the average ejection fraction was 58%. The presence of thrombus was noted in 7.3%, and 7.2% had moderate to severe tortuosity of the lesion. The angiographic success rate was 92%. Individual clinical sites reported that 66.3% of the stents were placed after suboptimal PTCA, 20.3% for abrupt closure and 13.4% for some other technical PTCA failure. Major in-hospital events occurred in 9.7% of patients, including death in 1.7%, Q wave myocardial infarction in 3.1% and emergency bypass surgery in 6%. Abrupt closure of a stented segment occurred in 3.1% of patients at a mean of 3.9 days. Cerebrovascular accident occurred in 0.3%, and transfusion was required in 10.6%. Vascular events with surgical repair occurred in 8.6% of patients. CONCLUSIONS: Despite these complications, the use of this device for the treatment of a failed or suboptimal PTCA result remains promising given the adverse outcome of abrupt closure with conventional (nonstent) treatment.

VEGF administration in chronic myocardial ischemia in pigs.

OBJECTIVE: Previous investigations have shown the effectiveness of sustained intra- or extravascular administration of vascular endothelial growth factor (VEGF) in chronic myocardial ischemia in improvement of left ventricular function. The present investigations were undertaken in order to evaluate efficacy of a single bolus or local intracoronary delivery. METHODS: Yorkshire pigs underwent placement of a left circumflex artery ameroid occluder. Three weeks later the animals were randomized to treatment with VEGF (20 micrograms) accomplished by local intracoronary delivery system (InfusaSleeve, n = 10), intracoronary bolus infusion (n = 7) or by epicardial implantation of an osmotic delivery system (n = 7). An additional group of animals received intracoronary administration of saline and served as a control (n = 9). Three weeks after initiation of therapy, the animals were evaluated with regard to myocardial perfusion and global as well as regional ventricular function. RESULTS: All three VEGF treatment groups but not the control animals demonstrated a significant increase in the left-to-left (but not right-to-left) collateral index, myocardial blood flow (pre-therapy LCX vs. LAD (average of all groups): 0.76 +/- 0.35 vs. 0.96 +/- 0.38 ml*min-1*g-1, p = 0.03; post-therapy: LCX vs. LAD: 1.16 +/- 0.39 vs. 1.15 +/- 0.28 ml*min-1*g-1, p = NS) and coronary vasodilatory reserve 3 weeks after growth factor administration. The observed increase in VEGF-induced perfusion correlated with improvement in regional ventricular function in all VEGF-treated groups (pre-therapy vs. post-therapy: i.c. VEGF 20 +/- 5.1 vs. 33 +/- 4.8; local VEGF 16 +/- 2.8 vs. 33.6; pump VEGF 17 +/- 3.8 vs. 34 +/- 4.9 p < 0.05 for all) but not control animals (21 +/- 3.3 vs. 27 +/- 5.8, p = NS). CONCLUSION: Single intracoronary delivery (intravascular bolus or local delivery) of VEGF is effective in stimulating physiologically significant angiogenesis in porcine model of chronic myocardial ischemia.

Cardiogenic shock induced by cocaine in swine with normal coronary arteries.

OBJECTIVE: The aim was to test the hypothesis that acute intravenous cocaine administration can cause coronary microvascular constriction culminating in myocardial ischaemia and cardiogenic shock. METHODS: Systemic haemodynamic variables and coronary blood flow were measured in 14 Yorkshire swine at baseline and following intravenous administration of 1, 3, and 10 mg.kg-1 of cocaine. Epicardial coronary artery diameter was measured from coronary arteriograms and coronary flow velocity was recorded with a Doppler flow wire. RESULTS: Cocaine produced a decrease in mean arterial pressure (65%), cardiac output (80%), and stroke volume (80%), and an increase in pulmonary artery diastolic pressure (60%). Although coronary blood flow decreased by 70%, epicardial coronary cross sectional area decreased by only 37-45%. Pretreatment with prazosin did not abolish the decrease in coronary blood flow. After administration of 10 mg.kg-1 of cocaine, five of 14 animals developed myocardial ischaemia and cardiogenic shock, culminating in ventricular fibrillation and death. CONCLUSIONS: In anaesthetised Yorkshire swine, cumulative intravenous doses of cocaine caused a significant reduction in coronary blood flow resulting in myocardial ischaemia, which cannot be attributed to epicardial vasoconstriction alone. This suggest that cocaine-induced coronary ischaemia may result from microvascular constriction, which is only partially prevented by alpha 1 blockade. In addition, direct toxic effects of cocaine on the myocardium may also contribute to the development of cardiogenic shock.

Economic assessment of rheolytic thrombectomy versus intracoronary urokinase for treatment of extensive intracoronary thrombus: Results from a randomized clinical trial.

BACKGROUND: Despite advances in mechanical and pharmacologic therapy, thrombus-containing lesions are at high risk for adverse events and remain a challenging subset for percutaneous coronary revascularization. Recently, rheolytic thrombectomy with the AngioJet device has been shown to safely remove intracoronary thrombus, but the overall cost-effectiveness of this technique is unknown. METHODS: We determined in-hospital and 1-year follow-up costs for 349 patients with overt intracoronary thrombus who were randomly assigned to treatment with intracoronary urokinase (6- to 30-hour infusion followed by definitive revascularization; n = 169) or immediate thrombectomy with the AngioJet device (n = 180) as part of the Vein Graft AngioJet Study (VeGAS) 2 trial. Catheterization laboratory costs were based on measured resource utilization and 1998 unit costs, whereas all other costs were estimated from hospital charges and cost center-specific cost-to-charge ratios. RESULTS: Compared with urokinase, rheolytic thrombectomy reduced the incidence of periprocedural myocardial infarction (12.8% vs 30.3%, P <.001) and major hemorrhagic complications (2.8% vs 11.2%, P <.001) and shortened length of stay by nearly 1 day (4.2 vs 4.9 days; P =.02). As a result, AngioJet treatment reduced procedural costs, hospital room/nursing costs, and ancillary costs with resulting hospital cost savings of approximately $3500 per patient during the initial hospitalization ($15,311 vs $18,841, P <.001). These cost savings were maintained at 1 year of follow-up ($24,389 vs $29,109, P <.001). CONCLUSIONS: Compared with standard treatment with intracoronary urokinase, rheolytic thrombectomy both improves clinical outcomes and reduces overall medical care costs for patients with extensive intracoronary thrombus.

Complications of directional coronary atherectomy: incidence, causes, and management.

An assessment of complications is essential to the evaluation of directional coronary atherectomy. Major complications--such as death, Q wave myocardial infarction, or the need for emergency bypass surgery to correct acute vessel closure--result from a variety of familiar mechanisms, including dissection, thrombosis, or guiding catheter injury. In addition, unique complications of this device, such as catheter nose cone injury or vascular perforation, may also result in severe ischemia. With prompt recognition of the cause, most ischemic complications can be successfully treated in the catheterization laboratory. Less severe complications, such as femoral vascular injury, also require recognition and appropriate treatment in order to minimize sequelae. Although several large series have now documented that the overall incidence of atherectomy complications appears similar to that reported for conventional balloon angioplasty, no direct comparisons can be made until randomized trials (such as Coronary Angioplasty Versus Excisional Atherectomy Trial [CAVEAT]) are analyzed, to control for potential demographic or lesion-specific influences on complication rates.

Usefulness of ST-segment elevation in lead III exceeding that of lead II for identifying the location of the totally occluded coronary artery in inferior wall myocardial infarction.

The presence of ST-segment elevation in lead III exceeding that of lead II, particularly if combined with ST elevation in lead V1, proved to be a powerful marker for occlusion of the proximal or midportion of the right coronary artery. These findings helped to determine the extent of myocardium at risk in inferior wall myocardial infarction and may further guide the decision to administer thrombolytics.

Acute and long-term outcome of narrowed saphenous venous grafts treated by endoluminal stenting and directional atherectomy.

Angioplasty of the narrowed saphenous vein bypass grafts remains a difficult challenge. Over a 37-month period at this institution, 119 of 176 interventions (68%) on saphenous vein grafts (average age 8.3 years from bypass surgery to graft intervention) were performed using either directional coronary atherectomy (n = 35) or Palmaz-Schatz intracoronary stents (n = 84), representing 37% of all stents and 15% of all atherectomies during the study period, respectively. Of the 57 saphenous vein graft lesions treated with conventional balloon angioplasty during this period, 49 (86%) had 1 or more contraindications to stenting or directional atherectomy (thrombus, total occlusion, reference vessel less than 3 mm in diameter). The acute success rate was 99% for stents (1 failure to dilate) and 94% for directional atherectomy (2 failures to cross the lesion with the atherectomy device). Lumen diameter increased from 0.9 to 3.6 mm (reference vessel 3.6) for stents, and from 0.9 to 3.5 mm (reference 3.8) for atherectomy (for all comparisons, p = not significant), with no major complications (abrupt or subabrupt closure, emergent coronary bypass surgery, death, or Q-wave myocardial infarctions). During the same time period 50 of 57 vein grafts (88%) rejected for stenting or atherectomy were dilated successfully by conventional balloon angioplasty, with 3 patients (5%) requiring emergent coronary bypass surgery. Angiographic follow-up was available for 50 of 64 eligible patients (78%).(ABSTRACT TRUNCATED AT 250 WORDS)

The impact of optimal stenting techniques on cardiac catheterization laboratory resource utilization and costs.

Coronary stenting has been shown to reduce angiographic restenosis and improve clinical outcomes compared with conventional balloon angioplasty, but at greater in-lab cost. Recent studies have suggested that "optimal" stent deployment can eliminate the need for intensive oral anticoagulation after stenting, with the potential to reduce vascular complications, length of stay, and hospital cost. Between January and June 1995, we performed elective 1-vessel coronary stenting in 78 patients with a single, discrete (< 15 mm) coronary stenosis (optimal single-lesion group) and in 30 patients with either a single, long stenosis or serial discrete lesions (optimal multilesion group). Compared with stent patients from the Stent Restenosis Study (STRESS) economic substudy, optimal single-lesion stenting required more stents (1.3 +/- 0.6 vs 1.1 +/- 0.4, p <0.01) and more adjunctive angioplasty balloons per patient (2.5 +/- 1.0 vs 2.0 +/- 0.9, p <0.01). As a result, catheterization laboratory costs for single-lesion stenting increased by nearly $600 between 1993 and 1995 ($4,619 +/- $1,120 [median $4,435] to $5,209 +/- $1,697 [median $4,6731, p <0.01). Compared with the STRESS angioplasty group, optimal coronary stenting increased catheterization laboratory costs by nearly $2,200 ($3,012 +/- $1,382 [median $2,548] vs $5,209 +/- $1,697 [median $4,673], p <0.01). Optimal stenting of long lesions or multiple discrete stenoses increased catheterization laboratory costs by an additional $2,000 compared with optimal single-lesion stenting ($7,201 +/- $2,428 [median $6,887] vs $5,209 +/- $1,697 [median $4,673], p <0.01). These findings demonstrate that optimal coronary stenting increases in-lab procedural resource utilization and costs compared with historical stenting techniques. Based on the downstream cost savings seen in the STRESS trial ($1,400/patient), it is unlikely that current optimal stenting techniques will result in an overall cost savings compared with balloon angioplasty.