Emergency stenting for acute occlusion after coronary balloon angioplasty

Intracoronary stenting in the treatment of acute or threatened closure in angiographically small coronary arteries (< 3.0 mm) complicating percutaneous transluminal coronary angioplasty

The effect of the Flex-Stent on immediate and long-term angiographic and clinical results for acute and threatened closure was evaluated in 42 consecutive patients with coronary arterial segments < 3.0 mm in diameter after percutaneous transluminal coronary angioplasty (PTCA). Forty-two consecutive patients were treated with Flex-Stent (2.0 or 2.5 mm) for acute or threatened closure complicating PTCA. Ten patients (24%) had acute closure and 32 (76%) had threatened closure with a residual luminal stenosis of > 50%. Successful stent deployment was achieved in 40 patients (95%) with a primary clinical success rate of 90% (freedom from myocardial infarction, coronary artery surgery, and death). In-hospital complications occurred in 5 patients (some patients fell into more than one category): 3 (7.1%) had coronary bypass surgery, 1 (2.4%) had acute stent thrombosis, 1 (2.4%) had subacute stent thrombosis, 2 (4.8%) had myocardial infarction, and 1 (2.4%) had dextran allergy. There was no hospital death. Clinical follow-up was complete at a mean of 14.8 +/- 7.6 months, and recurrence of angina was noted in 20 of 38 eligible patients (53%). Angiographic restenosis was found in 19 of 29 patients (66%) (76.3% of eligible patients) on follow-up angiography (mean 5.9 +/- 4.6 months). Fourteen patients (74%) underwent successful repeat PTCA at the stented site, 4 of 38 patients (11%) had bypass surgery. Intracoronary stenting in the treatment of acute or threatened closure in arteries < 3.0 mm is effective in improving the acute clinical outcome and is a viable nonsurgical alternative for this subset of patients.

Self expanding stents for the management of aorto-ostial stenoses in saphenous vein bypass grafts

OBJECTIVE

To assess the early and follow up results of implantation of a self expanding stent in aorto-ostial stenoses of vein grafts.

DESIGN

Prospective, non-randomised, observational study.

SETTING

Tertiary referral centre for cardiac diseases.

PATIENTS

Nineteen patients with ostial stenoses of saphenous vein grafts.

MAIN OUTCOME MEASURES AND RESULTS

Stents were successfully deployed in all 19 patients with satisfactory angiographic results. In one patient this required two attempts. There were no deaths and no major procedural complications related to ostial stenting. Before discharge two (11%) patients had thrombosis of the ostial stent; one patient had a Q wave myocardial infarction. Femoral artery bleeding occurred in three (16%) patients. Angiographic follow up was performed in 18 patients at a mean of seven months. Restenosis within the ostial stent was detected in three (16%) patients. Twelve (63%) patients had an improved functional status at a mean follow up of nine months. One patient died suddenly at three months. Three (16%) patients required additional revascularisation procedures because of symptoms caused by restenosis within the ostial stent during follow up.

CONCLUSIONS

Intracoronary stenting is an attractive treatment for the management of patients with vein graft ostial stenoses.

Should we avoid ostial implantations of Wiktor stents?

Complications arising during stent implantations in coronary arteries have been reduced by technological progress and the accumulated experience of interventional cardiologists. Retrospective and prospective randomized studies with several types of stents are currently available and show improved short and mid-term results. Wiktor stent provides increased flexibility for ease of implantation particularly in curved lesions. However, the flexibility of the Wiktor stent is also associated with low resistance in the longitudinal axis. We report four cases (in 4 out of 6 ostial lesions treated and 4 out of 43 Wiktor stents implanted during a 9-month period) in which stents have become unraveled during procedures on ostial lesions (2 saphenous venous grafts and 2 native coronary arteries). Death occurred in one case and one patient was treated by emergency coronary bypass surgery. In three cases the distal extremity of the guiding catheter stretched the stent meshes during the final control angiograms, and in one case the stent was stretched during withdrawal of the deflated balloon into the guiding catheter. We believe that it is preferable to avoid using this stent in ostial lesions.

Thrombosis and restenosis after stenting in failed angioplasty: comparison with elective stenting

The results of Palmaz-Schatz stent implantation in failed angioplasty in 60 consecutive patients were compared with those of elective stent implantation in 100 consecutive patients. Stent implantation was successful in all of the failed group and in 99% of the elective. Stent thrombosis occurred in 16.7% of the failed group and 2% of the elective (p = 0.001). In the failed angioplasty group, stent thrombosis was associated with a greater frequency of preprocedure complex morphology (40% vs 12% in the nonthrombosis group, p = 0.05), persistent uncovered dissection after stenting (60% vs 14%, p = 0.004), and greater residual stenosis (39.9% +/- 25.3% vs 24.9% +/- 13.08%, p = 0.008) after stenting. Vessel patency was reestablished by angioplasty in 5 of 10 with stent thrombosis. Of these 5 patients, however, 2 suffered repeat stent thrombosis; 1 died suddenly four months later; and restenosis occurred in the remaining 2. Follow-up angiography was performed in 98% of the elective group at 6.3 +/- 2.6 months and 96% of the failed angioplasty group at 6.4 +/- 2.1 months. Restenosis (> or = 50% stenosis) occurred in 32% of the elective group and 50% of the failed angioplasty group (p = 0.041). Multiple logistic regression analysis identified multiple stent implantation (F = 6.75, p = 0.01) and triple-vessel disease (F = 3.46, p = 0.06) as independent positive predictors of restenosis. In conclusion, stent implantation in cases of failed angioplasty could be performed with a success similar to that of elective stent implantation but was associated with a greater frequency of stent thrombosis and restenosis.

Sizing the Gianturco-Roubin coronary flexible coil stent

The balloon expandable, stainless steel, flexible coil stent is a useful device for the management of acute or threatened closure after percutaneous transluminal coronary angioplasty. Appropriate sizing is important to optimize immediate results and reduce the risk of acute thrombosis and restenosis. The in vivo size at deployment of this stent at nominal inflation pressures has not been evaluated. Forty patients who received a single flexible coil stent (10 patients each for stent sizes 4.0, 3.5, 3.0, and 2.5 mm) were studied. The stents were deployed at 3-5 atmospheres. The actual stent size achieved by the stent during deployment was found to be significantly less than the nominal size, being 3.7 +/- 0.3, 3.2 +/- 0.2, and 2.8 +/- 0.2 mm for nominal stent sizes of 4.0, 3.5, and 3.0 mm, respectively (P < 0.005, P < 0.001, and P < 0.01). For a 2.5 mm stent, it was 2.4 +/- 0.2 mm (P = ns). Thus, for optimal results with this device, we recommend that vessels 2.0-2.4 mm in diameter be supported by a 2.5 mm stent, vessels 2.5-2.9 mm in diameter by a 3.0 mm stent, vessels 3.0-3.4 mm in diameter by a 3.5 mm stent, and vessels 3.5-4.0 mm in diameter by a 4.0 mm stent.

Improving results of bailout coronary stenting after failed balloon angioplasty

Stent implantation can be a valuable alternative to emergent bypass surgery to treat established or threatening abrupt closure following coronary balloon angioplasty. To evaluate several sequentially introduced changes in our practice of bail-out stenting, we compared the first (group I) and second half (group II) of our single center experience (n = 88). Use of bailout stenting increased over time (2% of all angioplasty procedures in group I vs. 6% in group II, P < 0.001), more often to prevent rather than to reverse abrupt closure. Technical success of stent implantation was unchanged (95% vs. 93%), and there was a decreasing trend for stent thrombosis (14% vs. 5%), in-hospital death (5% vs. 2%), Q-wave myocardial infarction (9% vs. 7%), and requirement for surgery (9% vs. 7%). The incidence of non-Q-wave myocardial infarction (29% vs. 7% P < 0.01), bleeding complications (27% vs. 7% P < 0.01), and hospital stay duration (11 +/- 11 vs. 8 +/- 5 days P < 0.05) decreased. Our data suggest that coronary stent implantation is currently an effective stand-alone bailout procedure for a large majority of failed angioplasty procedures.

Treatment of acute aortic dissections with expandable metallic stents: experimental study

PURPOSE

This experimental study was designed to evaluate the effectiveness of metallic stents for the treatment of acute aortic dissection.

MATERIALS AND METHODS

Thoracic aortic dissections were created in 14 mongrel dogs. Aortography performed immediately after creation of dissections showed two types of aortic dissections: rapid flow in the false lumen (group 1) and slow flow in the false lumen (group 2). Each group consisted of seven dogs. For each group, expandable metallic Gianturco stents were placed in five dogs and two dogs were used as controls.

RESULTS

A week later, false lumina were patent in all dogs in group 1 and thrombosed in all dogs in group 2. In group 1, the mean diameter of the true lumina was considerably enlarged from 5.9 mm +/- 1.6 to 9.9 mm +/- 2.8 and that of the false lumina significantly diminished from 9.1 mm +/- 1.3 to 5.2 mm +/- 2.3 (P < .05) after stent placement. In group 2, the true lumina were significantly dilated (5.2 mm +/- 2.3 vs 12.3 mm +/- 3.1, P < .05) and the false lumina disappeared completely (9.2 mm +/- 3.3 vs 0.0 mm, P < .01). Furthermore, the two control dogs in group 2 died of visceral ischemia due to the compression of the true lumen by the thrombosed false lumina, but the dogs with stents showed no symptoms of the visceral ischemia.

CONCLUSION

Expandable metallic stents are not effective in obliterating the false lumen in acute aortic dissection but may be useful in maintaining the blood flow in the true lumen and avoiding visceral ischemia.

Usefulness of the Wiktor stent for treatment of threatened or acute closure complicating coronary angioplasty. The European Wiktor Stent Study Group

The purpose of this study was to determine the results of the first Wiktor stent implantations in bailout conditions. From December 1990 to July 1991, in a total of 10 centers, 69 patients presenting with threatened or total closure after balloon angioplasty each received the Wiktor stent in 1 coronary artery. In these 69 coronary arteries, a total of 72 stent deliveries were attempted and 69 were successful (delivery success rate 95%). Delivery failure was treated conservatively in 2 patients and surgically in 1 patient. Emergency surgery was also performed in 2 patients, who after successful stent delivery showed progressive distal extension of the dissection. In addition, 5 patients underwent elective surgery to avoid the possibility of stent thrombosis because the myocardial area at risk was considered too large. Postprocedural blood transfusion was performed in 6% of the patients, whereas stent thrombosis occurred in 10 of 59 patients (17%), resulting in 2 deaths. Finally, 65% of the patients had a successful stent implantation without major periprocedural complications. At 6-month follow-up, only 9% of the patients experienced recurrent angina, whereas a > 50% arterial diameter narrowing was observed in 27% of the patients. Thus, the radiopaque Wiktor stent can be accurately and conveniently implanted in dissected coronary arterial segments. However, as for similar bailout devices, the number of thrombotic and bleeding events remains high.

Emergency coronary stenting for dissection during percutaneous transluminal coronary angioplasty: angiographic follow-up after stenting and after repeat angioplasty of the stented segment

OBJECTIVES

The purpose of this study was to assess the angiographic results after emergency coronary stenting and after repeat angioplasty for restenosis within the stent.

BACKGROUND

There is still little angiographic information about lumen renarrowing and its correlates after emergency stenting, and data with regard to the angiographic outcome of repeat angioplasty within the stent are almost nonexistent.

METHODS

This study was based on the quantitative evaluation of angiograms performed before and immediately after intervention and at 6-month follow-up. The study included 164 of the 183 eligible patients with emergency Palmaz-Schatz stent implantation and 31 of those with restenosis within the stent who had repeat angioplasty.

RESULTS

Stenting produced an improvement in minimal lumen diameter from 0.82 +/- 0.41 to 2.76 +/- 0.47 mm (mean +/- SD) and in diameter stenosis from 74.9 +/- 11.5% to 18.3 +/- 8.1%. Elastic recoil was 0.51 +/- 0.34 mm, or 16%. At 6-month follow-up, 32.3% of the patients had restenosis (> or = 50% stenosis). Minimal lumen diameter decreased to 1.84 +/- 0.78 mm, and diameter stenosis increased to 41.7 +/- 21.0%. The degree of lumen loss correlated significantly with the length of the original stenosis and the initial lumen gain achieved by stenting. Thirty-one patients with in-stent restenosis underwent repeat angioplasty. The primary success rate was 100%, and no abrupt vessel closure was verified. Minimal lumen diameter increased from 0.85 +/- 0.35 to 2.18 +/- 0.39 mm, and diameter stenosis decreased from 69.7 +/- 12.9% to 28.6 +/- 9.4%. Elastic recoil was 0.82 +/- 0.38 mm, or 27%. At follow-up, 38.5% of the patients had restenosis. Minimal lumen diameter was reduced to 1.72 +/- 0.67 mm, and diameter stenosis increased to 42.4 +/- 18.1%.

CONCLUSIONS

Angiographic results of emergency coronary stenting compare favorably with those of conventional angioplasty. In-stent balloon redilation in patients with restenosis is associated with excellent short-term results and a restenosis rate not different from that reported for nonstented vessels.

Temporary stent as a bail-out device during percutaneous transluminal coronary angioplasty: preliminary clinical experience

OBJECTIVE

To evaluate the safety and efficacy of a prototype temporary stent (RX Flow Support Catheter, Advanced Cardiovascular Systems) in maintaining coronary perfusion and improving vessel patency in the event of acutely compromised flow complicating percutaneous transluminal coronary angioplasty.

DESIGN

Prospective clinical study as part of a multicentre trial.

SETTING

Regional cardiac centre catheterisation laboratory.

PATIENTS

Eight patients undergoing routine percutaneous transluminal balloon coronary angioplasty in whom coronary artery dissection resulted in impaired coronary artery flow with angina or electrocardiographic ST segment shift, needing bail-out treatment at the time of the procedure.

RESULTS

The RX Flow Support Catheter was successfully used and improved coronary flow in all cases, with a reduction in luminal stenosis and resolution of symptoms. The temporary stent was expanded for an average of 85 (range 30-209) minutes. In six patients it was used as a bridge to further treatment (permanent stent in four and coronary artery surgery in two) and two patients did not need further treatment.

CONCLUSION

The temporary stent was safe and effective in the acute management of coronary dissection. The main advantages are its ease and speed of use, and successful restoration of coronary flow both to the distal artery and to affected side branches pending definitive treatment.

Preliminary experience with intravascular ultrasound guided Palmaz-Schatz coronary stenting: the acute and short-term results on a consecutive series of patients

The purpose of this study was to prospectively test the hypothesis that systemic anticoagulation is not needed following coronary stenting when adequate stent expansion is achieved and documented and other flow limitations eliminated. Intravascular ultrasound (IVUS) was used to confirm adequate stent expansion, which was defined as good plaque compression together with the achievement of an intrastent lumen cross-sectional area (CSA) that was greater than 40% of the average reference vessel CSA. In this prospective study, Palmaz-Schatz coronary stenting was performed on 343 lesions in 263 consecutive patients. Primary stenting was successful in 254 patients (96.6%) and 332 lesions (96.8%). All patients with successful primary stenting underwent IVUS imaging except nine patients (13 lesions) that did not have an IVUS evaluation for technical reasons and three patients (4 lesions) in which IVUS was unsuccessful. The initial IVUS performed after achieving an acceptable angiographic result revealed inadequate stent expansion in 191 patients (79%) and 244 lesions (77%). After further dilatation, final adequate stent expansion was accomplished in 230 patients and 301 lesions. These patients were treated with Ticlopidine 250 mg twice per day for 2 months and did not receive postprocedure anticoagulation. There was one acute stent thrombosis (0.3%) that occurred in a lesion with slow flow and an inadequately expanded stent. There was no subacute stent thrombosis and no bleeding or vascular complications. We conclude that when adequate stent expansion is achieved and confirmed and other flow limiting lesions eliminated, that systemic anticoagulation after the stent procedure is not necessary.

Placement and angiographic patency of the Strecker coronary stent

The Strecker stent is a newer, balloon-expandable vascular prosthesis consisting of a single tantalum filament knitted into a flexible mesh tube. To test the placement characteristics and patency of this device, we implanted 29 stents in the coronary arteries of 24 juvenile Yorkshire swine. Seventeen stents were placed in the left anterior descending artery, and 12 were placed in the left circumflex system. All stents were deployed successfully. Four animals died within the first 24 hr of anesthesia-related complications. The remaining animals were sacrificed at 24 hr, 1 week, 2 weeks, or 4 weeks. Follow-up angiography demonstrated the patency of all stents. There were no episodes of stent migration or side branch occlusion. The Strecker stent has several favorable characteristics, including its unique delivery system, ease of deployment, flexibility, radiopacity, and radial strength. There was 100% patency at up to 4 weeks in this animal model. Further studies are required to define whether the knitted mesh design offers any advantage over previous models.

Intracoronary stents: a review of the experience with five different devices in clinical use

Atherosclerotic cardiovascular disease remains one of the most important causes of morbidity and mortality in the industrialized world. Treatment is basically aimed at palliation and consists of either pharmacological intervention or revascularization. The first significant advances in the latter were largely surgical. However, the pressing need for treatment with less invasive and potentially less expensive techniques, have stimulated the development of nonsurgical revascularization techniques. Percutaneous transluminal coronary balloon angioplasty, which was first performed by Andreas Gruentzig in 1977, is one of the most successful examples and provided the stimulus for a rapid technological growth of interventional cardiology. It is now widely accepted as a safe and effective treatment of obstructive coronary artery disease. However, the risk of abrupt vessel closure during or immediately after the intervention and the risk of late luminal renarrowing or restenosis continue to compromise its overall safety and efficacy. To improve the immediate and long-term results of balloon angioplasty, a number of new technologies such as intracoronary stenting, directional or rotational atherectomy, and laser therapy have been developed and represent the leading edge in the battle against atherosclerosis. The purpose of this paper is to review the experience and results of the various types of stents in clinical use.

Incidence, predictors, and management of acute coronary occlusion after coronary angioplasty

Acute coronary occlusion occurs in 4.3% to 8.3% of patients during coronary angioplasty. Its occurrence is difficult to predict in an individual patient. At high risk are patients with unstable angina, intracoronary thrombus, extreme age, long complex lesions, and diffuse disease. "Standard" management including redilation (prolonged perfusion) thrombolytic treatment and emergency bypass surgery is only successful in approximately 50% of the patients and is associated with a high mortality and myocardial infarction rate of < 6% and 30%, respectively. Bail-out stent implantation appears to emerge as an effective alternative in suitable patients and might reduce mortality, the apparent progression to myocardial infarction, or might decrease the need for emergency bypass. New techniques including directional atherectomy, rotational ablation, or the excimer laser are associated with a similar frequency of acute occlusion. Immediate access to a surgical back-up facility remains necessary to treat refractory acute occlusions.

Experience with the Gianturco-Roubin stent for abrupt vessel closure complicating percutaneous transluminal coronary angioplasty

BACKGROUND

Emergency coronary artery bypass grafting (CABG) has previously been the only option in the treatment of refractory abrupt vessel closure complicating percutaneous transluminal coronary angioplasty (PTCA), and has been associated with high rates of morbidity and mortality. Intracoronary stenting now provides an alternative to emergency CABG.

AIM

To assess our initial experience with emergency coronary artery stenting as a new technique.

METHODS

Retrospective case study review with clinical and angiographic follow-up.

RESULTS

The Gianturco-Roubin (GR) stent was deployed in 13 patients in whom PTCA was complicated by abrupt vessel closure refractory to standard balloon techniques. Indications for PTCA were unstable angina (six), stable angina (six) and acute myocardial infarction (MI) (one). The arteries stented included left anterior descending (LAD) artery lesions (eight) and right coronary artery lesions (five). Two patients required urgent CABG, one due to failed stent deployment and one for inadequate control of vessel dissection. In seven of the stented patients the creatine kinase rose to greater than twice the upper limit or normal. Three patients had subacute thrombotic occlusion at seven to 19 days post stent deployment, managed with intravenous thrombolysis or repeat PTCA. At seven months follow-up, 11 patients were free of angina, two patients had Canadian Heart Association class II angina and there were no deaths. Eleven patients had repeat angiography at mean six months post stent. Five patients had evidence of restenosis managed with repeat PTCA in four and CABG in one.

CONCLUSIONS

The GR stent is an effective alternative to urgent CABG in the treatment of refractory abrupt vessel closure complicating PTCA.

Comparison of results of intracoronary stenting in patients with unstable vs. stable angina

Percutaneous transluminal coronary angioplasty (PTCA) has higher complication and restenosis rates when performed in the setting of unstable angina. Balloon-expandable intracoronary stenting is a new technique with the potential to improve the results of PTCA. In order to determine whether stenting is associated with a poorer outcome in patients with unstable angina, we retrospectively examined our experience with the Palmaz-Schatz balloon-expandable intracoronary stent in 105 patients. Patients were divided into 2 groups on the basis of symptoms at the time of stent insertion: group I (n = 57) had stable angina pectoris, and group II (n = 48) had unstable angina defined as pain at rest despite antianginal therapy (Braunwald class II, III). Initial (30-d) and final (6-mo) success rates were defined as stent insertion without myocardial infarction, need for bypass surgery, death, and significant angina. Baseline characteristics were similar, although the patients with unstable symptoms were older, more likely to be female, and had a higher incidence of postinfarction angina. A total of 136 stents were successfully delivered to 97 target sites in 92% of patients. Major complications occurred in 4 patients (4%) and were due to subacute thrombosis in 3 of them. There were no differences in complication rates between patients receiving stents electively with stable vs. unstable symptoms (2% vs. 6%, p = NS). Six-mo. follow-up status was ascertained in 96% of patients and revealed overall clinical success in 83% with angiographic restenosis (> or = 50% stenosis) in 28% of patients. There were no significant differences between groups in rates of restenosis, follow-up angina class, or overall clinical success.(ABSTRACT TRUNCATED AT 250 WORDS)

A novel strategy for stent deployment in the treatment of acute or threatened closure complicating balloon coronary angioplasty. Use of short or standard (or both) single or multiple Palmaz-Schatz stents

OBJECTIVES

The purpose of this study was to determine the immediate and long-term angiographic and clinical results of coronary stenting as a specific therapy for intracoronary dissection associated with acute or threatened closure complicating percutaneous transluminal coronary angioplasty.

BACKGROUND

Published reports contain conflicting results with regard to the benefit of stent insertion for coronary dissection. In particular, there is a wide range in the reported rates of subacute occlusion.

METHODS

Palmaz-Schatz stents were inserted in 56 patients who had significant dissections and acute or threatened closure complicating coronary angioplasty. An attempt was made to cover the entire site of the dissection with short or standard single or multiple Palmaz-Schatz stents. The use of the short stent allowed complete coverage of the dissection, specifically in situations such as marked vessel tortuosity or the need to place a stent distal to a deployed stent.

RESULTS

A single stent was implanted in 24 patients and multiple stents were implanted in 32 patients. A total of 138 stents (78 standard, 60 short stents) were implanted. The primary clinical success rate was 88% (49 of 56 patients). Complications occurred in seven patients (12.5%): Three patients (5%) required urgent bypass surgery; two patients (4%) had a myocardial infarction; and two patients (4%) died. Subacute occlusion occurred in one patient (2%). Clinical follow-up was available in all patients at a mean of 10 +/- 4 months. Thirty-nine (80%) of 49 patients were clinically asymptomatic. Angiographic restenosis was found in 15 (36%) of 42 patients on angiographic follow-up performed a mean of 5 months (median 6) after the procedure in 86% of the eligible patients. Nine patients had successful repeat angioplasty, and two had elective bypass surgery.

CONCLUSIONS

The strategy of coronary stenting to completely cover the lesion is an effective treatment for large coronary dissection complicating angioplasty. A total major complication rate of 12.5% may be acceptable for this high risk group.

Improved anticoagulation management after Palmaz Schatz coronary stent implantation by sealing the arterial puncture site with a vascular hemostasis device

Sealing the arterial puncture site with a vascular hemostasis device has the potential to maintain optimal anticoagulation after stent implantation. The level of heparinization during the first 3 days after successful stent implantation was retrospectively compared between 2 groups of medically treated patients with (group A; n = 18) and without (group B; n = 17) a Vasoseal after sheath removal. The number of APTTs sampled in group A and B was 233 and 168, respectively. Respective mean values of APTT (seconds) in group A and B were 180 +/- 79 and 172 +/- 91 at day 1 (p = NS), 132 +/- 43 and 125 +/- 61 at day 2 (p = NS) and 123 +/- 36 and 116 +/- 48 at day 3 (p = NS). More APTTs were suboptimal (< 80 secs) in group B (34/168; 20%) compared to group A (17/233; 7%) [p < 0.001]. More patients in group B compared to group A had 1 or more (14/17; 82% vs. 8/18; 44%; p = 0.04), 2 or more (10/17; 59% versus 3/18; 17%; p = 0.02) and 3 or more (8/17; 47% vs. 2/18; 11%; p = 0.03) suboptimal APTTs. Bleeding complications were seen in 4 patients without and in 3 patients with a Vasoseal. Thus application of a vascular hemostasis device results in a less variable anticoagulation after coronary stenting, but it does not abolish entry site-related bleeding complications.

Emergency coronary stenting for acute occlusive dissection of the left main coronary artery

Catheter-induced left main coronary artery dissection is a rare but serious complication of diagnostic cardiac angiography. We report the case of a patient with mitral regurgitation and accidental dissection of the left main coronary artery successfully managed with intracoronary stent that allowed emergent surgical revascularization and mitral replacement.

Subcutaneous heparin in postangioplasty management: comparative trial with intravenous heparin

Abrupt closure of a coronary artery after successful angioplasty remains a problem for the interventionalist. Many laboratories continue to administer heparin intravenously for 12 to 24 hours in an attempt to alleviate this problem. But prolonged heparin therapy delays sheath removal and may lead to groin and vascular complications, and so prolong the hospital stay. To test the hypothesis that subcutaneous heparin was as efficacious as intravenous heparin in preventing acute closure while reducing the vascular complications associated with extended sheath placement, we prospectively randomized 151 patients to two groups. The intravenous group, 77 patients, received continuous intravenous heparin at 1000 units/hour for 12 to 18 hours; the subcutaneous group, 74 patients, received 12,500 units subcutaneously every 12 hours for three doses after sheath removal 2 to 3 hours after the angioplasty. The activated clotting time immediately after the angioplasty was 401 +/- 108 seconds in subcutaneous group, as compared with 368 +/- 67 seconds in the intravenous group (p = 0.028). Patients receiving subcutaneous heparin continued to show adequate anticoagulation, with a PTT of 85 +/- 21 seconds obtained approximately 12 hours after the procedure. The PTT at discharge was statistically greater in the subcutaneous group, at 49.2 +/- 21 seconds, versus 35.6 +/- 13 seconds in the intravenous group (p < 0.001). Abrupt occlusion was similar in both groups, but the hematomas and bleeding/oozing in the intravenous group was significantly higher when compared with that of the subcutaneous group, 16 versus 6 (p = 0.026) and 26 versus 7 (p < or = 0.002), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Multicenter clinical experience with rescue atherectomy for failed angioplasty

Directional coronary atherectomy (DCA) has been proposed as a "rescue" technique for failed or suboptimal percutaneous transluminal coronary angioplasty (PTCA) in an attempt to avoid myocardial infarction or emergency coronary artery bypass grafting. In this report we review the utilization and outcome of rescue atherectomy from the clinical experience of The Cleveland Clinic Foundation and Medical College of Virginia from November 1988 through January 1993, and from the Coronary Angioplasty Versus Excisional Atherectomy Trial (CAVEAT) database. This analysis includes 100 patients with 103 treated lesions from 44 patients at the Cleveland Clinic, 36 patients from the Medical College of Virginia, and 20 patients from the CAVEAT database. The etiology of failed PTCA was primarily from dissection in 52 lesions (50.5%), "recoil" in 43 lesions (41.8%), and recurrent thrombosis in 8 lesions (7.8%). Complete vessel closure was present in 23 lesions (22.3%). The vessels treated included 51.5% left anterior descending, 24.3% right coronary, and 16.5% circumflex coronary arteries. The average reference vessel diameter in the group was 3.10 +/- 0.06 mm (SEM), with an average stenosis of 78.9 +/- 1.2% before PTCA, 55.8 +/- 2.4% after PTCA, and 24.1 +/- 2.2% after rescue DCA. DCA was successful (Thrombosis in Myocardial Infarction [TIMI] grade 3 flow with > 20% stenosis reduction without death, Q-wave myocardial infarction, or coronary artery bypass grafting) in 94 of 103 lesions (91.3%). Complications included 1 patient with perforation (1%), 2 deaths within 24 hours (2.0%), and 6 patients requiring coronary artery bypass grafting (6%).(ABSTRACT TRUNCATED AT 250 WORDS)

Simultaneous implantation of two Palmaz-Schatz stents mounted on a long angioplasty balloon

Three cases are presented in which two Palmaz-Schatz stents were implanted simultaneously in a native coronary artery or saphenous vein graft. The two stents were mounted in tandem on a long angioplasty balloon. This technique has advantages in ease of delivery and positioning, with prevention of stent overlap, and when deployment of multiple stents is clinically appropriate.

Bail-out coronary stenting in an extremely tortuous right coronary artery with the Palmaz-Schatz stent and Teleguide sheath

Significant vessel tortuosity is a relative contraindication to the use of the Palmaz-Schatz coronary stent for fear of stent displacement during delivery. We describe a patient with unstable angina in whom conventional coronary angioplasty in an extremely tortuous right coronary artery resulted in an occlusive dissection. Emergency bypass surgery was avoided by the successful placement of a protected Palmaz-Schatz stent using a 5F Teleguide sheath.

Interventional techniques for the management of coronary artery lesions: an update

Coronary balloon angioplasty has become standard treatment for ischemic coronary artery disease. Major limitations of angioplasty are the inferior results obtained with unfavorable lesions, the occurrence of abrupt occlusion responsible for in-hospital mortality and morbidity, and the high restenosis rate at 6 months. New techniques for stents, laser, and atherectomy have been developed to overcome these limitations. Until now, although the initial results are encouraging, these new techniques have not as yet shown to be clearly superior to balloon angioplasty. However, due to the limitations of balloon angioplasty, further development of new techniques should be stimulated so that nonsurgical treatment of coronary artery disease will become safer, more effective, and applicable to a wider spectrum of coronary artery disease.

Long-term outcome following successful reopening of abrupt closure after coronary angioplasty

Abrupt closure after coronary angioplasty is often successfully treated by repeat dilation. Long-term follow-up, including 6-month repeat catheterization and 12-month clinical evaluation, was obtained in 1,056 patients treated with acute (n = 335) or elective (n = 721) coronary angioplasty to evaluate the long-term impact of successful reopening of abrupt closure. Abrupt closure occurred in 13.5% of patients and was successfully reopened in 58%. Adverse outcomes including restenosis, death, bypass surgery, myocardial infarction and repeat angioplasty were compared between patients with successfully treated abrupt closure and those with successful procedures (residual diameter stenosis < or = 50%) without abrupt closure. For patients with acute angioplasty, the restenosis rates (> 50% diameter stenosis at follow-up) were 64% for those with successfully treated abrupt closure versus 36% for those with successful procedures without abrupt closure (p < 0.01). In addition, subsequent myocardial infarction (12 vs 3%; p = 0.01) and repeat angioplasty (21 vs 10%; p = 0.03) were more frequent in the group with abrupt closure. For patients with elective angioplasty, restenosis was 43% in those with successfully treated abrupt closure versus 45% in those without abrupt closure (p = NS). Subsequent death and myocardial infarction were more frequent in patients with abrupt closure (death: 12 vs 3% [p < 0.01]; myocardial infarction: 13 vs 3% [p < 0.01]). Long-term adverse events are increased in patients with successfully treated abrupt closure compared to those with successful procedures without abrupt closure.

Emergency coronary stenting with the Palmaz-Schatz stent for failed transluminal coronary angioplasty: results of a learning phase

This study describes initial results of Palmaz-Schatz stent implantation in our department to restore and maintain vessel patency in 52 patients with obstructive dissection, defined as an intraluminal filling defect with coronary flow impairment after percutaneous transluminal coronary angioplasty (PTCA). The majority of patients (62%) underwent PTCA for unstable angina (n = 28), defined as angina at rest with documented ST segment changes resistant to nitrates, or acute myocardial infarction (n = 4). In six patients (11%) the stent could not be delivered. Seven of the remaining 46 patients (15%) had coronary artery bypass surgery performed because of increased risk for subacute stent occlusion, residual thrombosis, residual obstruction near the stent, coronary artery diameter less than 3.0 mm, or multiple and overlapping stents. One patient (3%) died in hospital from intracranial bleeding. Nine patients (23%) had subacute stent occlusion, retrospectively unpredictable in four patients. Nine of 29 patients (29%) with an uncomplicated clinical course after stenting had angiographic restenosis at a mean follow-up of 6.0 +/- 1.4 months (range 12 days to 8.3 months). Two patients (7%) died 3 months after successful stenting: one patient because of stent thrombosis after stopping warfarin before an abdominal operation and one patient after acute vascular surgery for late traumatic groin bleeding. Of the 39 medically treated patients with a stent, three (8%) had major bleeding complications. It is concluded that stent implantation is feasible in most patients with obstructive dissection after PTCA. After successful stent delivery, coronary flow is temporarily restored.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary and circulatory support strategies for percutaneous transluminal coronary angioplasty in high-risk patients

PTCA is now applied to patients with unstable acute ischemic syndromes, severe multivessel coronary artery disease, and impaired left ventricular function. To minimize the risk during angioplasty, several coronary and systemic circulation support approaches have been developed as adjuncts to high-risk angioplasty. Local coronary support techniques include the perfusion balloon catheter, the coronary stent, directional coronary atherectomy, laser balloon angioplasty, perfluorocarbon coronary perfusion, coronary sinus retroperfusion, and distal coronary hemoperfusion. Systemic circulatory support includes intraaortic balloon counterpulsation, cardiopulmonary support, the hemopump, and left heart partial bypass. These support devices, while associated with significant complications, may ultimately improve the safety of coronary angioplasty and allow its application to those who would otherwise not be candidates for revascularization.

Coronary stenting for treatment of acute or threatened closure following dissection after coronary balloon angioplasty

We studied 32 patients (age 58 +/- 9 years) who had been treated with a Palmaz-Schatz stent after significant dissection complicating percutaneous transluminal coronary angioplasty (PTCA). We attempted to cover the entire site of dissection with prosthesis. The presence of dissection after PTCA was associated with Thrombolysis in Myocardial Infarction grade 0 to 1 flow in 19 patients and grade 2 flow in 13. The stented arteries were: left anterior descending artery in 19 patients, right coronary artery in seven, and left circumflex artery in five. A single stent was implanted in 11 and multiple stents in 21 patients. Angiographic success was achieved in 30 patients (94%). Two patients (6%) had urgent coronary artery bypass graft surgery, two (6%) had a myocardial infarction, and one (3%) patient died. Subacute occlusion occurred in one patient (3%). Angiographic restenosis was found in three of nine patients (33%) with a single stent and 11 of 17 (65%) with multiple stents. Clinical follow-up at 11 +/- 3 months showed the necessity of coronary artery bypass graft surgery in two patients and repeat PTCA in nine (31%). We conclude that coronary stenting is an effective treatment for significant coronary dissection after PTCA with an acceptable incidence of major cardiac events at follow-up.

Implantation of half Palmaz-Schatz stents in short aorto-ostial lesions of saphenous vein grafts

Two cases are presented in which a half Palmaz-Schatz stent was implanted in a short lesion located in the ostium of a saphenous vein graft. Aorto-ostial stenoses are a technical challenge for balloon angioplasty and stenting. Short stents may offer several advantages as regards deployment, positioning, thrombogenicity, and restenosis.

Endovascular stents: preliminary clinical results and future developments

At present, there is an exponential use of new interventional techniques whose proper role and value have not yet been defined. The intracoronary stent is just one example. There is no doubt that stents can be implanted with a high technical success rate associated with highly predictable immediate angiographic results and that they appear to be superior to all other interventional techniques. However, the intrinsic thrombogenicity of all devices currently available for clinical use warrants a vigorous anticoagulation, exposing the patient either to the risk of (sub)acute stent thrombosis or to the risk of hemorrhage and vascular complications. It remains to be determined whether stent implantation will reduce the incidence of restenosis and whether this results in an improved long-term event and symptom-free survival. Experimental studies indicate that the thrombogenic nature of stents may be controlled by coating the struts with endothelial cells or polymers. With respect to restenosis, it is evident that as long as mechanical injury is applied to the vessel wall, the vessel wall will respond with neointimal thickening. The intracoronary stent has the potential to control this tissue response by serving as a carrier for local antiproliferative drug delivery or eventually for genetic manipulation. The intensive research which is now going on in combination with experimental animal data, human postmortem pathologic observations, and angiographic studies is yielding clear insights and future directions to address these issues.

Retrieval of a lost coronary stent from the descending aorta using a PTCA balloon and biopsy forceps

We report a case of unsuccessful stenting of a right coronary artery after acute dissection during percutaneous transluminal coronary angioplasty (PTCA). The stent was lost in the descending aorta and we used an original technique to remove it from the arterial bed by using both a very low profile balloon and a 6F bioptome.

Intracoronary stenting compared with conventional therapy for abrupt vessel closure complicating coronary angioplasty: a matched case-control study

OBJECTIVES

A case-control analysis was performed to compare clinical outcome after intracoronary stenting with that after conventional therapy for abrupt vessel closure.

BACKGROUND

Previous studies have demonstrated that stenting after abrupt vessel closure results in marked angiographic improvement and preservation of coronary flow, leading to the anticipation of similar improvement in clinical outcome.

METHODS

Sixty-one of 92 consecutive patients treated at two clinical sites by intracoronary stenting for abrupt vessel closure were matched, according to angiographic features of closure and estimated left ventricular mass threatened by ischemia, with patients treated conventionally during the 18 months before stent availability. In 33 pairs of matched patients, vessel closure was established; in 28 pairs, it was threatened (coronary dissection or worsening stenosis with preservation of normal anterograde flow). Baseline clinical and angiographic characteristics were comparable in the two matched groups. Patients with indeterminate mechanisms of total occlusion (31%) or dissections < 15 mm long (43%) predominated; patients with visible thrombus (8%) or dissections > 15 mm long (18%) were infrequently represented. Stents were successfully deployed in 60 of 61 patients at a median of 52 min (range 3 to 269) after the onset of closure.

RESULTS

When compared with conventional treatment, stenting resulted in less residual stenosis (26% vs. 49% diameter stenosis, p < 0.001), a greater likelihood of restoration of Thrombolysis in Myocardial Infarction (TIMI) grade 3 blood flow (97% vs. 72%, p < 0.001) and a reduction in the need for emergency bypass surgery (4.9% vs. 18%, p = 0.02). However, the incidence of Q wave myocardial infarction was nearly the same in the two groups (32% vs. 20%, respectively, p = NS). In the group with stenting, peak creatine kinase level and the frequency of Q wave infarction after established vessel closure increased with the time to stent placement (p = 0.001 and 0.054, respectively); the incidence of procedure-related Q wave infarction in patients who underwent stenting within 45 min of closure was very low (3.9%). In-hospital death occurred in 3.3% of patients in each treatment group. At a mean of 6.3 months of follow-up after hospital discharge, survival free from late cardiac death, myocardial infarction, bypass surgery or coronary angioplasty was 74.9% and 81.3% in the stent and the control treatment group, respectively (p = NS).

CONCLUSIONS

Although early treatment of established vessel closure by intracoronary stenting was associated with a low incidence of both myocardial infarction and emergency bypass surgery, the likelihood or severity of infarction was not reduced among those in whom stents were implanted later. Patients with threatened vessel closure could not be shown to benefit from stent treatment. These data provide preliminary indications for stent placement in the acute period to be validated in larger randomized studies.

Coronary stenting through 6 French guiding catheters

Most stent implantation procedures currently require the use of large-diameter guiding catheters. We describe our preliminary successful experience with 6 French guiding catheters to deliver balloon-expandable Palmaz-Schatz stents to the coronary arteries.

Thrombosis of a flexible coil coronary stent: frequency, predictors and clinical outcome

OBJECTIVES

The aim of this study was to evaluate the predictors and clinical sequelae of stent thrombosis.

BACKGROUND

Although coronary artery stenting is being increasingly applied, the major unique complication of stent thrombosis is not well characterized.

METHODS

We studied 145 patients who underwent coronary artery stenting with the Gianturco-Roubin flexible coil design for abrupt vessel closure or to prevent restenosis. There were 17 stented vessel closures (11.7%), 7 as a result of acute (< 24 h) and 10 of subacute (days 1 to 21) thrombosis.

RESULTS

In seven patients successful coronary recanalization was achieved with thrombolytic agents and balloon angioplasty. Creatine kinase was significantly elevated in 13 patients, with a Q wave myocardial infarction in 11 and emergency coronary artery bypass grafting in 8. Comparisons (multivariate analysis) with a control cohort (n = 33) of patients without thrombosis matched for age, gender and vessel stented revealed lesion eccentricity (p = 0.003), unstable angina (p = 0.048) and indication for stent implantation (abrupt closure versus restenosis) (p = 0.002), as predictors of thrombotic occlusion of stented vessels. Subtherapeutic anticoagulation (activated partial thromboplastin time < 2 times control value, prothrombin time < 1.4 control value) occurred at least once during the hospital stay in all 10 patients with subacute thrombosis and in 20 of 33 control patients (p = 0.047). In 2 patients with subacute thrombosis and 11 control subjects, subtherapeutic anticoagulation was necessitated by bleeding.

CONCLUSIONS

Early thrombosis after coronary stenting was relatively common (> 10%), occurring predominantly in eccentric lesions and in patients with unstable angina pectoris. This complication is associated with significant adverse clinical outcomes and may be reduced by more intensive anticoagulation yet, in a delicate balance, can be precipitated by inadequate heparin therapy.

Quantitative analysis of elastic recoil after balloon angioplasty and after intracoronary implantation of balloon-expandable Palmaz-Schatz stents

OBJECTIVES

The purpose of this study was to measure elastic recoil from sequential angiograms after balloon angioplasty and after implantation of a balloon-expandable Palmaz-Schatz stent in the same patient, and to compare the results with the late angiographic outcome.

BACKGROUND

The immediate result of coronary balloon angioplasty is influenced by plastic deformation, primarily of the atherosclerotic plaque, and by elastic recoil, primarily of the less or nondiseased vessel circumference.

METHODS

The extent of elastic recoil was measured quantitatively as the difference between maximal balloon size and the resulting vessel diameter or cross-sectional area.

RESULTS

Analysis was performed in 60 patients who received a single stent for late restenosis after initially successful coronary balloon angioplasty. Minimal lumen diameter (minimal cross-sectional area) was 0.98 +/- 0.43 mm (0.97 +/- 0.67 mm2) before balloon angioplasty, 2.06 +/- 0.36 mm (3.68 +/- 1.17 mm2) after angioplasty (both p < 0.001 vs. values before angioplasty) and 2.98 +/- 0.26 mm (7.12 +/- 1.28 mm2) after stenting (both p < 0.001 vs. postangioplasty results). No significant changes in vessel reference diameters or areas were measured. Mean balloon/artery ratios were similar in both procedures, ranging from 0.93 to 0.96. The calculated mean elastic recoil was 0.98 +/- 0.50 mm in diameter (31%) and 3.67 +/- 2.05 mm2 in area (48%) after balloon angioplasty compared with 0.10 +/- 0.07 mm (3.5%) and 0.38 +/- 0.36 mm2 (5.1%) after stenting. Increasing balloon sizes induced increased vessel stretch, which was followed by increased elastic recoil in the angioplasty group in contrast to the stenting group. Short, noncalcified and eccentric lesions tend to be associated with increased recoil after balloon angioplasty. Overdilation or underdilation in one of the procedures, changes in postprocedural vasomotion or postprocedural thrombus formation was not responsible for this outcome. After 6 months mean minimal lumen diameter was 2.39 +/- 0.58 mm, suggesting a mean hyperplasia of 0.59 +/- 0.51 mm. Twelve patients (20%) had a follow-up diameter that was equal to or less than the mean postangioplasty result and eight patients (14%) had a diameter stenosis of > 50%.

CONCLUSIONS

The implantation of a Palmaz-Schatz stent almost completely eliminates the decrease in vessel dimensions caused by elastic recoil and therefore diminishes the impact of hyperplasia and reduces the rate of restenosis.

Platelet and fibrin deposition on coronary stents in minipigs: effect of hirudin versus heparin

OBJECTIVES

The present study was designed to test the hypothesis that the direct thrombin hirudin is more efficient than heparin in reducing thrombus formation after coronary stenting.

BACKGROUND

Despite aggressive anticoagulation, subacute thrombosis of coronary stents is a major complication associated with these new devices.

METHODS

In 19 minipigs indium-111-labeled thrombocytes and iodine-125-labeled fibrinogen were injected 14 to 19 h before coronary implantation of tantalum balloon-expandable stents. In group 1 (n = 6, seven stents), a bolus of heparin (100 U/kg body weight) was given before stenting. Group 2 (n = 6, 11 stents) received both dextran (500 ml) and heparin (a 100-U/kg bolus followed by a continuous infusion of 50 U/kg per h). In group 3 (n = 7, 13 stents), hirudin (recombinant desulphatohirudin HV 1 [CGP 39393] [1 mg/kg]) was given before stent implantation, followed by an infusion of 1 mg/kg per h. All animals were pretreated with aspirin (250 mg intravenously).

RESULTS

Activated partial thromboplastin time was prolonged to > 1.8 times control values in groups 2 and 3. Histologic examination after perfusion fixation 12 h after stenting showed a variable extent of thrombus on all stents. Medial tear was observed in three stents in group 1, six stents in group 2 and six stents in group 3. The number of platelets on all stents averaged 116.2 (range 22 to 522) x 10(6) in group 1, 64.3 (range 11 to 169) x 10(6) in group 2 and 19.7 (range 9 to 38) x 10(6) in group 3 (p < 0.05 vs. group 1 and vs. group 2). The increase in platelet deposition, associated with medial tear in all groups, was lowest in the hirudin group. Similarly, fibrin deposition was lowest on stents in hirudin-treated animals.

CONCLUSIONS

Recombinant hirudin significantly reduces platelet and fibrin deposition on coronary stents compared with the reduction achieved with combined heparin, dextran and aspirin.