Emergency stenting for acute occlusion after coronary balloon angioplasty

Autoperfusion balloon catheter for complicated coronary angioplasty: a prospective study with retrospective controls

Prolonged angioplasty balloon inflation with an autoperfusion balloon for failed conventional coronary angioplasty, was compared with emergency surgery for this condition. Restenosis was assessed 6 weeks after successful intervention with the autoperfusion balloon. Forty consecutive patients with persistent acute occlusion and/or severe intimal dissection during conventional angioplasty, were treated with the autoperfusion balloon. They were candidates for emergency surgery if it failed. Total inflation time was significantly longer (p < 0.001) with the autoperfusion balloon (27.5; 10-180 min) than with the standard balloon (10; 1-20 min) (median; range). The number of inflations was significantly lower (p < 0.001) with the autoperfusion balloon (2; 1-5 times) than with the standard balloon (5; 2-14 times) (median; range). Two patients died, one before surgery could be performed. The autoperfusion balloon was successful in 26 patients (65%). After 6 weeks, 16 (62%) were asymptomatic without anti-anginal medication, 24 underwent repeat angiography, 10 (42%) had restenosis, 7 (27%) underwent elective bypass surgery. Emergency surgery remained necessary in 13 patients (33%), 9 received arterial grafts. In 31 retrospective controls, who had undergone immediate surgery for the same indication, only venous grafts could be used. Thus, prolonged autoperfusion balloon inflation was successful in 65% of the cases of failed, conventional angioplasty. The angiographic restenosis rate after 6 weeks was 42%. If emergency surgery remained necessary, the autoperfusion balloon facilitated the use of arterial bypass grafts.

Peripheral stent recovery after failed intracoronary delivery

The Palmaz-Schatz stent can be successfully deployed in most patients. However, in a small percentage of instances a systemic embolism of the stent has been reported. In the present article we describe an easy and fast method of stent capture when detachment from the balloon has happened (pulling back the stent-loaded balloon into the guiding catheter or femoral sheath). In this situation we propose the use of the coronary guide-wire "as a guide" to capture coaxially the lost stent. This method allows for continuing the procedure without removal of the femoral sheath.

Changing incidence and management of abrupt closure following coronary intervention in the new device era

Abrupt closure of the dilated segment occurs in approximately 4 to 7% of cases following conventional percutaneous coronary angioplasty. Additional balloon angioplasty reverses roughly 40% of these closures, to yield an overall 1.6 to 3.4% rate of emergent surgery. The impact of new devices on the incidence and reversal rate of abrupt closure has not been examined. Abrupt closure occurred in 80 (4.2%) of 1,919 consecutive coronary angioplasties performed in our single center, 389 (20%) of which were performed using newer interventions (208 Palmaz-Schatz stents, 170 directional coronary atherectomies, and 11 elective laser balloon angioplasties). Abrupt closure was less frequent following newer coronary interventions (1.8%) compared to standard balloon angioplasty (4.9%, P < 0.01), possibly reflecting case selection. When abrupt closure did occur, percutaneous rescue was successful in 53 (66%) patients, including 42 (53%) who were rescued using standard or perfusion balloon angioplasty, and 11 (13%) who were rescued using laser balloon balloon angioplasty after failure of additional angioplasty attempts. Medical therapy alone was used in 8 (10%), while emergent coronary bypass surgery was performed in 18 (23%), yielding an overall emergent surgery rate of 0.9%. Q-wave myocardial infarction was significantly less frequent (0.2%) following percutaneous rescue, compared to either medical therapy (25%) or emergent surgery (33%, P < 0.001). In our catheterization laboratory, use of these 3 new coronary interventional devices coincides with a trend towards a lower incidence of abrupt closure, a higher percutaneous rescue rate with reduced incidence of myocardial infarction, and a lower emergent bypass surgery rate.

Early and late outcome following deployment of a new flexible tantalum intracoronary stent in dogs

A new radiopaque, highly flexible balloon-expandable tantalum stent was tested. Thirty-six of 40 stents were successfully deployed percutaneously in the coronary arteries of 31 dogs. The dogs were given aspirin before, intravenous heparin during, and aspirin alone after the procedure. One dog died at 24 hours because of coronary occlusion following traumatic implantation. Four dogs were put to death early, revealing re-endothelialization by 9 days. Eleven dogs were put to death from 2 weeks to 9 months during long-term follow-up, showing all vessels widely patent with the stent uniformly embedded within a stable neointimal layer. Follow-up arteriography showed patency in all remaining stents up to 1 year, with no perforation or aneurysm formation. Four stents were placed into canine peripheral arteries and were removed percutaneously after deployment. Pathology revealed no significant trauma to involved vessels. This tantalum stent exhibits feasibility of percutaneous deployment, early neointimal formation, low thrombogenicity on long-term aspirin therapy alone, and patency up to 1 year in this canine model.

A new bioabsorbable intravascular stent: in vitro assessment of hemodynamic and morphometric characteristics

Currently available intracoronary stents are permanent and their placement may be complicated by thrombosis and restenosis. We have developed a new bioresorbable stent constructed of type I collagen. This stent has a compliant tubular structure that is self expanding and carries a net negative surface charge to increase hemocompatibility. In vitro histologic and morphometric examination was performed by deploying the stent in six pressure fixed explanted porcine arteries. Morphometry revealed a close relationship between the stent external diameter 2.9 +/- 0.4 mm) and the arterial lumen diameter (3.0 +/- 0.4 mm). A relative reduction in arterial lumen diameter secondary to stent placement of 17% to 26% was observed. Folding of the stent wall was noted in those preparations where the stent external diameter was larger than the arterial lumen diameter. Polyvinyl chloride (PVC) tubing was used as a mock arterial segment for flow studies. Flow at baseline and following stent placement was determined at perfusion pressures of 10, 50, and 80 mmHg. A modest reduction in flow following stent placement of between 2% and 6% was observed. Thus, type I collagen may be used to construct a self expanding tubular stent. Morphometric and hemodynamic evaluation reveals a modest impact on arterial lumen dimensions and flow.

Long-term clinical and angiographic follow-up of patients treated with the self-expanding coronary stent for acute occlusion during balloon angioplasty of the right coronary artery

A self-expanding coronary stent was implanted in 17 patients to treat acute occlusion of the right coronary artery after percutaneous transluminal angioplasty. There were 2 women and 15 men, with a mean age of 59 +/- 8 years. All patients underwent at least one follow-up angiographic examination 4 to 6 months after implantation and six patients had additional follow-up angiography. During a mean follow-up interval of 32 +/- 10 months no patient died or had a myocardial infarction. Restenosis within the stent did not occur. Two patients had a new stenosis adjacent to the stent. Stent occlusion was found on follow-up angiography in one patient who had not been treated with an antiplatelet agent. The mean intraluminal diameter was 2.77 +/- 0.5 mm after implantation and 2.67 +/- 0.5 mm on follow-up angiography. It is concluded that coronary stenting is effective in treating right coronary artery occlusion after balloon angioplasty. Immediate and long-term outcome suggest that the right coronary artery may be a particularly favorable site for stent implantation.

Abrupt vessel closure complicating coronary angioplasty: clinical, angiographic and therapeutic profile

To assess the clinical, angiographic and procedural correlates of outcome after abrupt vessel closure during coronary angioplasty, results were analyzed of 109 patients (8.3%) who had abrupt vessel closure during 1,319 consecutive coronary angioplasty procedures performed between July 1, 1988 and June 30, 1990. These 109 patients had a mean age of 59 +/- 11 years; 63% were male, 57% had had a prior myocardial infarction and 61% had multivessel disease. Coronary angioplasty was performed in the settings of acute myocardial infarction (14%), recent myocardial infarction (36%), unstable angina (34%) and stable ischemia (29%). Abrupt vessel closure occurred at a median of 27 min (range 0 min to 5 days) from the first balloon inflation. By angiographic criteria, thrombus or coronary dissection was identified in 20% and 28% of cases, respectively; both thrombus and dissection were present in 7% of closures, and 45% were due to indeterminate mechanisms. Successful reversal of abrupt vessel closure, defined as restoration of normal Thrombolysis In Myocardial Infarction (TIMI) grade 3 flow without resultant Q wave myocardial infarction, emergency bypass surgery or death, was achieved in 47 patients (43%). By hierarchal analysis, the incidence of death, emergency coronary bypass surgery, Q wave and non-Q wave myocardial infarction was 8%, 20%, 9% and 11%, respectively. Univariate analysis using 23 clinical, morphologic and procedural variables demonstrated that successful outcome after abrupt closure was associated with prolonged balloon inflations (greater than 120 s) (odds ratio = 6.87, p less than 0.001), unstable angina (odds ratio = 2.37, p = 0.034) and placement of an intracoronary stent (odds ratio = 5.33, p = 0.062). By multivariate analysis, independent correlates of successful outcome were prolonged balloon inflations (odds ratio = 5.11, p = 0.001) and intracoronary stenting (odds ratio = 4.37, p = 0.049). Thus, although prolonged balloon inflations and intracoronary stents may improve outcome after abrupt vessel closure, the cumulative risk of morbidity or mortality remains significant and mandates investigation into improved strategies for its prevention and treatment.

Angioplasty of the proximal left anterior descending coronary artery: initial success and long-term follow-up

From 1984 to 1987, 537 consecutive patients (mean age 58 years; range 34 to 79) underwent angioplasty for proximal left anterior descending coronary artery disease. The procedure was clinically successful in 516 (96.1%). Procedural complications included myocardial infarction (2.2%; Q wave 0.9%, non-Q wave 1.3%), in-hospital bypass surgery (3%) and death (0.4%). Follow-up was obtained in 534 patients (99.8%) for a mean duration of 44 months (range 8 to 75). Follow-up cardiac catheterization, performed in 391 patients (76%), demonstrated a 39.6% angiographic restenosis rate. Ninety-eight (19%) of the patients with a clinically successful result required additional revascularization for recurrent left anterior descending artery disease by angioplasty (12.8%) or coronary artery bypass grafting (4.7%), or both (1.5%). During follow-up there was a 2.5% incidence rate of myocardial infarction (anterior myocardial infarction 1.6%), and 27 patients (5.2%) died, 14 (2.7%) of cardiac causes. The actuarial 5-year cardiac survival rate was 97%, freedom from cardiac death and myocardial infarction was 94% and freedom from cardiac death, myocardial infarction, coronary artery bypass surgery and repeat left anterior descending artery angioplasty was 77%. At last follow-up 76% of patients were free of angina and 88% reported sustained functional improvement. Angioplasty is an effective treatment for proximal left anterior descending coronary artery disease that has a high success rate, low incidence of procedural complications and provides excellent long-term cardiac survival, freedom from cardiac events and sustained functional improvement.

Vascular pathology of balloon-expandable flexible coil stents in humans

The morphologic changes in atherosclerotic coronary arteries and saphenous vein bypass grafts after placement of a balloon-expandable flexible coil stent (Cook) are described. In each case, the vessels were patent despite morphologic evidence of injury and dissection in the vessel wall. The stented region was reendothelialized and the tissue overlying the stent wires consisted primarily of smooth muscle cells. There was minimal inflammatory reaction to the stent wires. These findings suggest that the balloon-expandable flexible coil stent can effectively maintain vessel patency even in the setting of postangioplasty lumen disruption. In addition, the vessels tolerate the metal prosthesis with little evidence of tissue inflammatory reaction.

Percutaneous implantation of a new intracoronary stent in pigs

Sixty-two self-expanding parallel wire stainless steel stents were implanted in normal coronary arteries of 31 young pigs using a newly developed delivery system. In 57 of 62 procedures, the percutaneous coronary implant of the stent was successful; five stents were released in side branches. Implants remained in place for a few hours to 6 months. In spite of correct sizing, two stents migrated out of the coronary arteries. Seven pigs died prematurely; in six of them death might be stent-related. Although no anticoagulant and antiplatelet aggregation drugs were administered during the follow-up period, at autopsy thrombi were observed in only seven arteries (nonobstructive in four of seven arteries). All arteries except for three were patent; these three vessels occluded probably due to oversizing of the stent. Complete neointimal coverage was found within 3 weeks. Important hyperplasia was not seen. It was concluded that coronary implantation of this stent usually was easy. Obstructive thrombus formation was rather uncommon despite the absence of chronic anticoagulant and antiplatelet aggregation therapy. Hyperplasia was rare.

Flow support catheter for prolonged maintenance of coronary blood flow

A newly designed flow support catheter with a supporting wire mesh cage which can be expanded into a tubular configuration and then readily reduced was evaluated in mongrel dogs. Regional myocardial blood flow (RMBF) was measured using the radioactive microsphere technique in the area of both balloon-denuded instrumented and control non-instrumented coronary arteries following placement of either a fixed-wire or a higher profile rapid exchange flow support catheter. At 5, 20, and 180 min following delivery and expansion of either device, RMBF was not significantly different in left ventricular subepicardium and subendocardium perfused by the instrumented vs. the control coronary arteries. Angiography demonstrated widely patent instrumented arteries in 15/18 dogs; in no dog was side branch occlusion observed. Significant cage thrombus deposition was seen angiographically in 3 animals causing temporary total coronary occlusion in 1. Following reduction and removal of the flow support catheter, vessel patency was present in all dogs. The flow support catheter is an effective endovascular stenting device capable of providing structural arterial support, while simultaneously maintaining distal coronary blood flow. It is envisioned that the primary application of this catheter will be to enable primary salvage of vessels acutely injured during coronary angioplasty, by "tacking up" intimal flaps for an extended period. It may also provide a bridge to emergency surgical revascularization.

A solution to the problem of an unexpanded Palmaz-Schatz stent following balloon rupture

The Palmaz-Schatz stent is a balloon expandable stent. Although easy to deploy, problems can occur. One problem is balloon rupture resulting in a partially expanded stent, which can be difficult to expand fully. This report illustrates how a Probing catheter and balloon can solve this potentially serious problem.

Emergency coronary artery bypass surgery following failed balloon angioplasty: role of the internal mammary artery graft

During a 4-year period (1986-1989), 3,502 patients had percutaneous transluminal coronary angioplasty (PTCA) in our institution. One hundred nineteen (3.4%) patients required emergency coronary artery bypass graft surgery (CABG) because of abrupt vessel closure following PTCA. Factors associated with vessel closure included lesion angulation greater than or equal to 90 degrees (p less than 0.007), the presence of thrombus (p less than 0.02), or a long (greater than or equal to 2 cm) lesion (p less than 0.03). Of these 119 emergency CABG patients, 108 (91%) arrived in the operating room in a stable condition (group I) and 11 (9%) were in cardiogenic shock (group II). Five (45%) of the group II patients were admitted to the hospital with an acute myocardial infarction and all 11 patients had a higher incidence of multivessel disease (p less than 0.05) and lower left ventricular ejection fraction (p less than 0.001) than group I patients. The overall surgical mortality was 10.1%; however, in group I the mortality was 5.6% and in group II it was 54.5% (p less than 0.001). The vessel that abruptly closed ("culprit vessel") was the left anterior descending (LAD) in 60%, the right coronary artery in 27%, and the left circumflex in 13%. The internal mammary artery was utilized to bypass the culprit artery in 51 (43%) patients, including 50% of the culprit LADs. With group I culprit LAD patients, when the left IMA was the bypass conduit, there were no hospital deaths nor strokes and there was a 6.3% incidence of perioperative infarction.

Coronary aneurysms after stent placement: a suggestion of altered vessel wall healing in the presence of anti-inflammatory agents

Coronary aneurysms are rare after conventional angioplasty and have not been reported after coronary stenting. Coronary artery stent sites were examined by follow-up angiography at a median of 4 months in 29 patients who received the Cook stent (Gianturco-Roubin) for acute coronary closure. Nineteen patients were treated with glucocorticoids administered intravenously or orally, or both, with or without colchicine and results were compared with those in 10 patients who were treated with neither agent. Standard therapy for all patients included routine administration of aspirin and heparin before and warfarin sodium (Coumadin) and aspirin after stent placement. Most patients also received dipyridamole and lovastatin during the follow-up period. Compliance with medications was confirmed by telephone conversation with each patient. Six (32%) of the 19 stented arteries showed evidence of coronary artery aneurysm, defined as expansion of the lumen outside the margins of the stent. None of the patients in the control group (who did not receive steroids or colchicine) developed aneurysm. This pattern of altered vascular healing in stented coronary segments appears to be due to the addition of multiple anti-inflammatory drugs rather than to stent presence alone. This observation demonstrates the possibility of medical impairment of normal vascular remodeling after acute injury and stent placement, which may be of benefit in designing future trials on restenosis.

Effect of intracoronary stenting on intimal dissection after balloon angioplasty: results of quantitative and qualitative coronary analysis

The effect of the Palmaz-Schatz stent on the angiographic appearance and residual luminal stenosis in patients with intimal dissection after balloon angioplasty was evaluated in 84 consecutive patients (90 lesions). Coronary angiography was performed before angioplasty, after conventional angioplasty and after stent implantation. The degree of intimal disruption was assessed as follows: grade 0, no dissection; grade 1, simple dissection (intraluminal linear defect or extraluminal cap extravasation); or grade 2, complex dissection (nonlinear spiral defect or luminal defect with multiple irregular borders). Quantitative coronary analysis of digitized cineangiograms was performed with use of a computerized automatic edge detection algorithm. After balloon angioplasty, 31 (34%) of 90 lesions demonstrated intimal dissection (18 simple, 13 complex). After stent implantation, intimal dissection improved by greater than or equal to 1 grade in 29 (94%) of the 31 lesions with 27 (87%) reduced to grade 0 (that is, no dissection). Dissection grade improved after stenting in 16 (89%) of 18 simple dissections and in all 13 complex dissections. Mean diameter stenosis was 77 +/- 17% before angioplasty, 47 +/- 17% after angioplasty and 14 +/- 10% after stenting (before angioplasty vs. after angioplasty and after angioplasty vs. after stenting, p less than 0.0001). In conclusion, intracoronary stenting is effective in reducing the residual luminal stenosis and in improving the angiographic appearance of intimal dissections after conventional balloon angioplasty.

Short and long term results after intracoronary stenting in human coronary arteries: monocentre experience with the balloon-expandable Palmaz-Schatz stent

OBJECTIVE

Intracoronary stenting was designed to overcome acute complications after percutaneous transluminal coronary angioplasty and to achieve a reduced rate of restenosis, both of which are major limitations of this well accepted method for treating coronary heart disease. This report describes the experience at one centre with the implantation of balloon-expandable Palmaz-Schatz stents and focuses on device related complications and the short and long term angiographic outcome.

DESIGN

A retrospective data analysis.

PATIENTS

Stenting was attempted in 50 patients. Restenosis after an initially successful angioplasty procedure, inadequate postangioplasty results, saphenous coronary bypass stenoses, and bail-out situations were regarded as indications.

MAIN OUTCOME MEASURES AND RESULTS

In 49 of 50 attempted patients 61 stents (1-4 per patient) were implanted. Delivery problems occurred in three patients and were successfully overcome in two patients. Bail-out situations were successfully managed in 16 patients. Complications included acute thrombus formation within the stent immediately after implantation in one patient, which was successfully treated by thrombolysis. One patient was sent for bypass surgery the day after implantation; another died 10 days after implantation for unknown reasons. Subacute stent thrombosis occurred in seven patients 5-9 days after implantation and was successfully treated by thrombolysis or balloon angioplasty in five patients. Bleeding complications occurred in nine patients, five of whom required blood transfusions. Angiography showed long term vessel patency after 4-6 months in 31 (76%) of the 41 patients who were followed up, restenosis in six (14%), and reocclusion in four (10%). Late restenosis or reocclusion was found in five (15%) of 33 patients with a single stent in contrast to five (63%) of eight patients with multiple stents.

CONCLUSIONS

Balloon-expandable intracoronary stenting is a feasible method for treating the acute complications of balloon angioplasty. It reduced the rate of restenosis for single stent implantation. Subacute thrombotic events must be regarded as previously unknown and serious complications.

Interventional cardiology techniques for coronary artery disease

This review updates and extends observations made in this journal in March 1988. The focus then was on percutaneous transluminal coronary angioplasty and the clinical results of its practical application. A concern was expressed that science lagged in solving the major problems of rethrombosis and restenosis. The NHLBI Bypass Angioplasty Revascularization Investigation (BARI) study was still in the planning phase. In 1991, the scene has changed. Interventional cardiology now embraces a multitude of different catheter devices--angioplasty, atherectomy, laser, stents. Basic scientists are increasingly involved in addressing the restenosis issue. Our national heart meetings are increasingly oriented towards molecular biology approaches to solving the remaining problems. The BARI trial has nearly completed patient entry, and we eagerly await its results. The cardiologist and surgeon are faced with increasingly complex decisions with respect to interventional technologies, involving not only whether to use them, but which ones.

Use of a morphologic classification to predict clinical outcome after dissection from coronary angioplasty

To determine if morphology of procedure-associated dissections could help predict clinical outcome, angiograms of 691 coronary artery dissections resulting from percutaneous transluminal coronary angioplasty were categorized according to the National Heart, Lung, and Blood Institute classification system. Classes of dissection were then correlated with clinical outcome: 543 patients with type B dissections had no increase in morbidity and mortality when compared with patients without dissection, with a similar success rate of 93.7%. Complications in this group were low and compared favorably with complication rates in procedures not associated with dissection. One hundred forty-eight procedures associated with dissections of types C to F had a significant increase in in-hospital complications, including acute closure (31%), need for emergency coronary bypass surgery (37%), myocardial infarction (13%) and repeat angioplasty (24%). The overall clinical success rate for those with types C to F dissection was 38%. The differences in clinical success and acute complications between type B and types C to F dissections were statistically significant at p less than 0.0005 for all variables studied. The angiographic morphology of a dissection during coronary angioplasty can predict clinical outcome, aiding in selection of effective therapy.

Short and long term outcome of percutaneous transluminal coronary angioplasty in unstable versus stable angina pectoris: a report of the 1985-1986 NHLBI PTCA Registry

In a cohort of 1,720 consecutive patients from the National Heart, Lung, and Blood Institute, Percutaneous Transluminal Coronary Angioplasty (PTCA) Registry (August 1985-May 1986), we compared 768 patients (45%) with stable angina and 952 patients (55%) with unstable angina pectoris. Unstable angina patients exhibited at least one of the following characteristics: new onset angina, rapidly progressing angina, angina at rest, angina refractory to medication, variant angina, acute coronary insufficiency, or angina recurring shortly after an acute myocardial infarct. The distribution of single- and multi-vessel disease was similar among stable and unstable angina patients; multi-vessel disease predominated. Average severity of stenosis and incidence of tubular and diffuse stenosis morphology were higher among patients with unstable angina (both p less than 0.001). Patient success rates were similar in stable and unstable patients. However, on a per lesion basis, overall angiographic success rate and average reduction of severity of stenosis in successfully dilated lesions were significantly higher among patients with unstable angina (both p less than 0.001). Incidence of major patient complications (p less than 0.01) and of emergency coronary bypass surgery (p less than 0.05) were also higher in patients with unstable angina but consistent with their more precarious clinical condition and stenosis morphology. During a two year follow-up, the cumulative distributions of death, myocardial infarct, repeat PTCA, and coronary bypass surgery were not significantly different in patients with stable angina compared to patients with unstable angina. Comparison of the current PTCA Registry cohort with the cases reported in the 1979-1982 Registry revealed a 19% higher success rate for both stable and unstable angina patients. Major complication rates decreased between time periods for stable but not for unstable angina patients. Incidence of emergency bypass surgery decreased more for stable than for unstable angina patients. Coronary angioplasty is indicated in properly selected patients with unstable angina and both single- and multi-vessel coronary disease.

Advances in coronary interventional techniques

The practice of catheter interventional techniques for coronary artery disease is just 14 years old. Many approaches are being applied, including balloon and rotational angioplasty devices, atherectomy catheters, lasers, and stents. Considerable efforts are being made developing, marketing and comparing these technologies. Restenosis is demanding more attention amongst clinical and basic scientists. The pathophysiology of this frequent and irksome complication is still poorly understood. A number of trials are comparing strategies of PTCA against medicine and surgery. In the United States, the Bypass Angioplasty Revascularization Investigation (BARI) of PTCA versus surgery for patients with multivessel disease has nearly completed patient entry; the preliminary results are eagerly awaited. Patients in nearly all countries are benefiting from these new technologies. Their development and evaluation has been most active in North America, Europe and Japan but many of them are being clinically applied in nearly all countries. Their cost and complexity present special challenges for funding, training and evaluation.

Coronary occlusion following diagnostic angiography: salvage by intracoronary stenting

Catheter-induced coronary artery dissection and occlusion is a rare but serious complication of diagnostic cardiac angiography. This report describes the successful management of this complication with an intracoronary stent after prolonged balloon inflations and intracoronary thrombolytic therapy were unsuccessful.

Laser balloon angioplasty: clinical, angiographic and histologic results

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

Initial clinical results with the Wiktor stent: a new balloon-expandable coronary stent

The Wiktor stent, a new coronary balloon-expandable tantalum stent, was implanted in 17 patients for other wise nonmanageable occlusion after balloon angioplasty (n = 11) and for recurrent restenosis (n = 6). Stents of 3.0 to 4.0 mm were implanted (right coronary artery: n = 10, left anterior descending artery: n = 4, left circumflex artery: n = 2, venous graft: n = 1). All patients were fully anticoagulated initially with heparin followed by coumadin for 3 months and were treated with acetylsalicylic acid indefinitely. Due to its good radiopacity, the device could be placed easily without complications. Early occlusion occurred in one patient after 8 h probably due to friable atheromatous material prolapsing between the meshes of the stent. Late occlusion occurred in another patient who was admitted in cardiogenic shock after pre-hospital reanimation and was stented after occlusive disection following balloon angioplasty of an occluded right coronary artery. In this patient with severe hypoxic brain damage, reocclusion and reinfarction to which the patient finally succumbed occurred following cessation of anticoagulation. Histology demonstrated occlusive thrombosis without evidence of a neointimal covering of the stent. Another thrombotic occlusion due to inadvertent omission of anticoagulation occurred in another patient two weeks after stenting. Control angiography after 6 months in 12 patients revealed restenosis in two patients (50% and 80%). The patient with 80% restenosis of the right coronary artery and pathologic results during stress testing underwent surgical revascularization. The other patient with a 50% restenosis of the right coronary artery was managed medically as he was asymptomatic and without evidence of ischemia during stress testing.(ABSTRACT TRUNCATED AT 250 WORDS)

Stenting of coronary arteries: has a modern Pandora's box been opened?

Interventional cardiology has recently witnessed the growth of several alternatives to percutaneous transluminal angioplasty, including coronary stenting. Although stenting appears to be useful in treating abrupt closure after coronary angioplasty, its effectiveness in limiting the complex processes responsible for late restenosis is much less certain. Pathologic examination of stented human saphenous bypass grafts shows extensive deposits of platelets, fibrin and leukocytes along the stent wires within the 1st week and formation of a neointima of variable thickness after 3 months without evidence of foreign body reaction. The long-term effects of continuous barotrauma induced by the expanded stent remain unknown. It is difficult to assess the relative merits of the new devices, but stenting has several theoretic advantages. It seems less disruptive to the underlying architecture of the vessel wall and enjoys favorable theoretic and effective expansion ratios. Wide-spread clinical acceptance for stenting will depend on demonstrating that its safety, efficacy and cost efficiency are superior to those of balloon angioplasty.

Clinical experience with the Palmaz-Schatz coronary stent

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

The morphology of coronary arterial dissection occurring subsequent to angioplasty and its influence on acute complications

We reviewed the records of 402 patients undergoing percutaneous transluminal coronary angioplasty to identify factors predicting an ischemic event with arterial disruption during an otherwise uncomplicated angioplasty. Major dissection of the coronary arteries without immediate occlusion was found in 25 patients, who exhibited 28 dissected lesions. Dissections were classified into 2 types: those producing a continuous extraluminal and parallel filling tract, and those with a continuous parallel filling tract extending into and compromising the lumen. Ischemic complications (defined as myocardial infarction, the need for repeat angioplasty, or coronary arterial bypass surgery) occurred in 6 patients (24%) within 24 hours of the completion of the procedure. The remaining 19 patients had an uncomplicated hospital course. Acute ischemic complications following dissection correlated with the percentage of luminal compromise 50 +/- 0% in those with complications as opposed to 17 +/- 21% in those without: P less than 0.001) and the development of dissection producing a filling tract which compromised at least half the lumen (100% in those with complications versus 9.1% in those without: P less than 0.001). There was a trend towards an increase in ischemic complications in patients with proximal and eccentric lesions. We conclude that patients who develop dissections which produce significant luminal compromise after an otherwise uncomplicated angioplasty are at a high risk of developing an acute ischemic complication within 24 hours of the procedure.

Long-term follow-up of the first 56 patients treated with intracoronary self-expanding stents (the Lausanne experience)

Fifty-six patients treated with the self-expanding intracoronary stent for acute occlusion during percutaneous transluminal coronary angioplasty (PTCA) or restenosis were followed for 24 to 43 months (mean 34). Successful deployment and positioning were achieved in 55 of 56 patients. Occlusion of the stent was documented in 8 patients, the earliest occurring 30 minutes and the latest 8 months after implantation. Three of the occluded stents were recanalized by PTCA. Coronary artery bypass grafts (CABG) were required in 4 patients: 1 for symptomatic restenosis, 1 for left main stenosis adjacent to the stent and 2 for acute ischemia during the in-hospital stay (less than 7 days). Myocardial infarction occurred in the territory of the stented vessel in 8 patients. Seven patients died between 1 day and 19 months after implantation. Local bleeding complications occurred in 10 patients, with 5 requiring blood transfusion. Restenosis within the stent was angiographically documented in 5 patients (9%). A new lesion in the treated vessel was found in 10 patients, followed by implantation of a second stent in 5 and a third stent in 1 patient. Medical treatment was instituted in the remaining 4 patients. Forty-nine patients (88%) are alive. Twenty-nine patients (51%) remained asymptomatic, and 44 (78%) are in a better functional class than before the implantation. Eleven of 15 (79%) major complications (acute occlusions or deaths) occurred in patients who received a stent in the left anterior descending coronary artery. In conclusion, implantation of the self-expanding intracoronary stent appears to be a new therapeutic option for treating acute occlusion or restenosis after PTCA.(ABSTRACT TRUNCATED AT 250 WORDS)

Percutaneous support devices for high risk or complicated coronary angioplasty

Indications for coronary angioplasty have expanded to include patients with unstable acute ischemic syndromes, severe multivessel coronary artery disease and impaired left ventricular function. Several mechanical approaches have been developed as adjuncts to high risk coronary angioplasty to improve patient tolerance of coronary balloon occlusion and maintain hemodynamic stability in the event of complications. These percutaneous techniques include intraaortic balloon counterpulsation, anterograde transcatheter coronary perfusion, coronary sinus retroperfusion, cardiopulmonary bypass, Hemopump left ventricular assistance and partial left heart bypass. The intraaortic balloon pump provides hemodynamic support and ameliorates ischemia by decreasing myocardial work; it may be inserted for periprocedural complications or before angioplasty in patients with ischemia or hypotension. Anterograde distal coronary artery perfusion may be accomplished passively through an autoperfusion catheter or by active pumping of oxygenated blood or fluorocarbons through the central lumen of an angioplasty catheter. Synchronized coronary sinus retroperfusion produces pulsatile blood flow via the cardiac veins to the coronary bed distal to a stenosis. Both perfusion techniques limit development of ischemic chest pain and myocardial dysfunction in patients undergoing prolonged balloon inflations. Percutaneous cardiopulmonary bypass provides complete systemic hemodynamic support which is independent of intrinsic cardiac function or rhythm and has been employed prophylactically in very high risk patients before coronary angioplasty or emergently for abrupt closure. These and newer 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.

Angiographic follow-up after placement of a self-expanding coronary-artery stent

BACKGROUND

The placement of stents in coronary arteries after coronary angioplasty has been investigated as a way of treating abrupt coronary-artery occlusion related to the angioplasty and of reducing the late intimal hyperplasia responsible for gradual restenosis of the dilated lesion.

METHODS

From March 1986 to January 1988, we implanted 117 self-expanding, stainless-steel endovascular stents (Wallstent) in the native coronary arteries (94 stents) or saphenous-vein bypass grafts (23 stents) of 105 patients. Angiograms were obtained immediately before and after placement of the stent and at follow-up at least one month later (unless symptoms required angiography sooner). The mortality after one year was 7.6 percent (8 patients). Follow-up angiograms (after a mean [+/- SD] of 5.7 +/- 4.4 months) were obtained in 95 patients with 105 stents and were analyzed quantitatively by a computer-assisted system of cardiovascular angiographic analysis. The 10 patients without follow-up angiograms included 4 who died.

RESULTS

Complete occlusion occurred in 27 stents in 25 patients (24 percent); 21 occlusions were documented within the first 14 days after implantation. Overall, immediately after placement of the stent there was a significant increase in the minimal luminal diameter and a significant decrease in the percentage of the diameter with stenosis (changing from a mean [+/- SD] of 1.88 +/- 0.43 to 2.48 +/- 0.51 mm and from 37 +/- 12 to 21 +/- 10 percent, respectively; P less than 0.0001). Later, however, there was a significant decrease in the minimal luminal diameter and a significant increase in the stenosis of the segment with the stent (1.68 +/- 1.78 mm and 48 +/- 34 percent at follow-up). Significant restenosis, as indicated by a reduction of 0.72 mm in the minimal luminal diameter or by an increase in the percentage of stenosis to greater than or equal to 50 percent, occurred in 32 percent and 14 percent of patent stents, respectively.

CONCLUSIONS

Early occlusion remains an important limitation of this coronary-artery stent. Even when the early effects are beneficial, there are frequently late occlusions or restenosis. The place of this form of treatment for coronary artery disease remains to be determined.

Emergent saphenous vein graft stenting for acute occlusion during percutaneous transluminal coronary angioplasty

This report describes the initial use in the United States of emergency intravascular stenting for the treatment of acute coronary occlusion complicating elective saphenous vein graft angioplasty. This case adds further support to the role of the balloon expandable stent as an effective "bail out" device for failed angioplasty.

Implantation of an endoluminal prosthesis at the distal anastomosis of a bypass graft for abrupt closure following balloon angioplasty

A coronary Wallstent was implanted in a 10-year-old saphenous vein bypass graft following a PTCA that was complicated by abrupt closure. Anterograde flow was restored and no myocardial necrosis resulted. One week later, bypass surgery was performed due to a bleeding complication associated with the anticoagulation regimen.

Quantitative angiographic comparison of the immediate success of coronary angioplasty, coronary atherectomy and endoluminal stenting

Coronary atherectomy and coronary stenting effectively reduce the severity of coronary artery stenoses, but direct comparisons of these interventions with conventional balloon angioplasty have not been performed. To compare the immediate efficacy of these 3 interventions, the angiographic morphology and the severity of the residual coronary stenosis were quantitatively evaluated in 18 patients undergoing coronary atherectomy and in 21 patients treated by endoluminal coronary stenting. Each of these groups of patients was compared with a matched group of coronary angioplasty patients selected from a large, computerized data-base. The variables matched included patient age and sex, lesions site and severity, and lesion complexity. Both coronary atherectomy and coronary stenting more effectively reduced the severity of the coronary stenosis when compared with balloon angioplasty. The luminal diameter stenosis was reduced from 69 +/- 10 to 22 +/- 20% in the atherectomy group compared with a reduction from 74 +/- 11 to 44 +/- 14% in the matched coronary angioplasty population (p = 0.008). Similarly, the luminal diameter stenosis was reduced from 77 +/- 11 to 26 +/- 12% in the stented group compared with a reduction from 81 +/- 10 to 42 +/- 14% in the matched coronary angioplasty group (p = 0.014). In addition, moderate or severe coronary dissections were noted more frequently in the coronary angioplasty groups than in their respective atherectomy and stent groups (0 vs 33%, p = 0.008, and 5 vs 19%, p = 0.15, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)