Three-year follow-up after implantation of metallic coronary-artery stents

Midterm results after minimally invasive coronary surgery (LAST operation)

BACKGROUND

Our experience with a left internal thoracic artery graft to the left anterior descending artery via a left anterior small thoracotomy is reviewed to evaluate midterm results.

METHODS

From November 1994 to April 1997, four hundred sixty patients were scheduled to undergo a left internal thoracic artery graft to the left anterior descending coronary artery via a left anterior small thoracotomy; 26 of these patients (5.7%) were converted and 434 of them had the operation. Two hundred fourteen patients (49.3%) had isolated disease of the left anterior descending artery, and 220 patients (50.7%) had multiple vessel disease. A sufficient length of the left internal thoracic artery was harvested to reach the left anterior descending artery.

RESULTS

Three hundred nine patients (71.2%) underwent extubation by hour 2. Mean intensive care unit stay was 4.2 +/- 4.5 hours; mean postoperative hospital stay was 66 +/- 29 hours; the 30-day mortality rate was 1.1%; the late mortality rate was 1.4%. Eighteen patients underwent reoperation early (< or = 30 days), and eight patients underwent reoperation late (> 30 days) because of conduit/anastomotic malfunction. Four patients underwent reoperation with patent anastomosis for progression of disease (n = 3) or pericarditis (n = 1). Three patients had a percutaneous transluminal coronary angioplasty. Cumulating angiographic and stress Doppler flow assessment results, a patent anastomosis was obtained in 417 patients and a nonrestrictive anastomosis in 404 patients. Twenty-nine months after surgery, survival was 97.1% +/- 0.7% (95% confidence interval 90.5% to 100%) and event-free survival 89.4% +/- 1.2% (95% confidence interval 78.2% to 100%). In the last 190 patients, with our increased experience and better instruments, we obtained a patent anastomosis in 188 patients (98.9%) and a nonrestrictive anastomosis in 185 (97.4%).

CONCLUSIONS

Left anterior small thoracotomy gives acceptable midterm results. Incidence of patent and nonrestrictive anastomoses was satisfactory, especially in the most recent part of our experience, when the learning curve ended.

beStent--the serpentine balloon expandable stent: review of mechanical properties and clinical experience

The objective of this study was to present the engineering and clinical aspects of a new balloon expandable coronary stent. A new tubular, serpentine design stainless steel balloon-expandable stent, the beStent, was designed based on clinical requirements for stents and has been clinically evaluated in multiple sites. The stent is featured by terminal gold markers and rotational junctions that assure no shortening upon expansion and lead to orthogonal locking, maximizing radial strength. In terms of methods and results, the stent was clinically evaluated in the framework of a pilot evaluation in a variety of lesion types. The short- and long-term results evaluated during the course of the beStent multicenter pilot evaluation and in our single center study are reported. A variety of patients were included, including patients with long complex lesions, restenosis lesions, and total occlusions. Short-term clinical success with stenting was achieved in more than 97% of the cases. Subacute thrombosis was low in 1% of the cases. Clinical restenosis rates were acceptable with an overall 85% 6 month event free survival. In conclusion, the mechanical features of the stent providing its flexibility, scaffolding properties, radial strength, and absence of shortening were tested in a clinical study, showing that it is safe and effective for treating simple as well as long and complex lesions associated with coronary disease with a relatively low rate of complications.

Balloon angioplasty versus new device intervention: clinical outcomes. A comparison of the NHLBI PTCA and NACI registries

OBJECTIVES

We sought to compare outcomes of patients treated in the National Heart, Lung, and Blood Institute (NHLBI) Percutaneous Transluminal Coronary Angioplasty (PTCA) and New Approaches to Coronary Intervention (NACI) registries.

BACKGROUND

Coronary angioplasty has numerous shortcomings. New devices for performing coronary interventions have been introduced in an effort to improve clinical outcomes.

METHODS

Under the sponsorship of the NHLBI, a registry of consecutive patients treated with PTCA during 1985 to 1986 was established. In 1990, the NHLBI funded a second registry, the NACI. The two registries used the same data coordinating center to collect detailed baseline and follow-up information.

RESULTS

Patients enrolled in the NACI registry were older, had undergone more previous bypass surgery procedures and had more stenoses located in bypass grafts than patients in the NHLBI PTCA registry. Procedural success was achieved in 72.1% and 82.6% of patients in the PTCA and NACI registries, respectively; however, in-hospital and 1-year mortality rates were 1.0% versus 1.8% and 3.1% versus 5.9% for the PTCA versus NACI registries, respectively. After risk adjustment, there was no difference in 1-year mortality. Rates of target lesion revascularization (TLR) were 21.5% for the PTCA registry and 24.2% for the NACI registry. NACI registry patients had a higher risk for TLR and the composite end point of death, myocardial infarction or revascularization (relative risk 1.28 and 1.23, respectively). However, the NACI registry patients who received stents tended to have a lower adjusted TLR rate.

CONCLUSIONS

This comparative study found no overall superiority of these newer devices in terms of patient survival or freedom from TLR after adjustment for baseline risk profiles. Although technologic improvements (especially improved stenting) continue, these observations highlight the importance of careful assessment of clinical results in the broad population of patients in whom interventions are used.

Total reconstruction of a diseased saphenous vein graft by means of conventional and autologous tissue-coated stents

This is the first report of a total reconstruction of a diseased saphenous vein graft, with thrombus-containing lesion and multiple stenoses, by the implantation of arterial graft- and venous graft-coated stents, and of conventional stents. The procedure was successful without any complications, and follow-up angiography after 6 months revealed patency of the vessel.

Gene therapy for restenosis: getting nearer the heart of the matter

Intensive work over the past decade has been directed to the study of vascular gene transfer as an approach to the unresolved problem of restenosis. This effort has resulted in a significant foundation of knowledge relative to the activities of potentially therapeutic gene products as well as the capabilities and limitations of vector systems and mechanical delivery modalities available for effecting the vascular expression of these gene products. In several instances, significant progress has been made by experiments highlighting unexpected difficulties and the need for more comprehensive understanding. It is thus now possible to clearly define and address specific challenges that must be overcome in order to make feasible progress from the preclinical to the clinical arena. The key challenges at present appear to include the evolution of clinically practical delivery methods that meet the kinetic requirements of achieving efficient gene transduction and the availability of vectors that maximize efficiency while minimizing undesirable host responses. Emerging data suggest that approaches to solving each of these issues may have recently been developed. Basic research evaluating these new delivery mechanisms and molecular vectors is essential to establish their true potential for use in the clinical arena.

Stenting of "unprotected" left main coronary artery stenoses: early and late results

OBJECTIVE

To assess short and long term efficacy of coronary stent implantation for unprotected left main coronary artery stenosis.

DESIGN

Retrospective follow up study.

SETTING

Tertiary referral centre for interventional cardiology and cardiac surgery.

PATIENTS

Eighteen consecutive patients (12 men; age 70.8 years) between May 1993 and July 1996. Ten patients presented with stable angina and underwent the procedure electively, eight patients presented either with unstable angina or myocardial infarction and underwent the procedure in emergency.

INTERVENTION

Johnson and Johnson Palmaz-Schatz stents were used in 16 patients, and a Microstent and a Gianturco-Roubin in one patient each. An intra-aortic balloon pump was prophylactively used for two patients in the elective group. In the acute group, six required an intra-aortic balloon pump.

MAIN OUTCOME MEASURES

Procedural success rate and major adverse cardiac events.

RESULTS

Successful stent implantation was achieved in all patients. In the elective group, no major adverse cardiac event occurred during the procedure, but one patient had to undergo repeated angioplasty before discharge. All patients of the elective group were discharged alive and there has been one non-cardiac death during a follow up of (mean (SD)) 10 (4) months. In the emergency group, one patient died during the procedure, one patient developed a non Q-wave myocardial infarction, one patient underwent emergency coronary bypass surgery, while another patient died suddenly before hospital discharge. Six patients of the emergency group were discharged alive and there has been one non-cardiac death during a follow up of 7 (4) months.

CONCLUSIONS

Elective stent implantation for unprotected left main coronary artery stenosis is safe and effective in selected stable patients. Urgent stent implantation, however, cannot be considered as a definitive procedure in emergency situation.

Clinical outcome at six months of coronary stenting followed by ticlopidine monotherapy

Antiplatelet therapy has been shown to be superior to oral anticoagulation after coronary stent implantation. Different regimens for postinterventional antiplatelet therapy have been proposed. A combination of ticlopidine and aspirin has gained the most widespread use. The relative merit of the different compounds in this combination remains unclear. There are several, partly conflicting, reports on coronary stent implantation followed by aspirin alone, but data on ticlopidine monotherapy are scarce. We conducted a prospective trial of elective coronary stenting followed by ticlopidine monotherapy in 263 consecutive, unselected patients. One-, 2-, and 3-vessel disease was present in 42.9%, 42.6%, and 14.5% of patients, respectively. We deployed a total of 322 stents. All patients received 250 mg of ticlopidine twice daily for up to 6 months. The clinical end points encountered during the hospital stay and at 5.9+/-2.9 months, respectively, were: death (2 [0.8%] and 2 [0.8%]); myocardial infarction (5 [1.9%] and 4 [1.5%]); target vessel occlusion (2 [0.8%] and 4 [1.5%]); bypass surgery (0 and 2 [0.8%]); and repeat angioplasty (2 [0.8%] and 52 [19.8%]). There was 1 vascular surgery (0.4%) and 4 (1.5%) non-procedure-related ischemic cerebrovascular events at follow-up. We conclude that coronary stent deployment followed by ticlopidine monotherapy is safe and effective in an unselected population. The overall clinical outcome at 6 months is good and comparable to that of patients treated with combined antiplatelet therapy. Ticlopidine monotherapy may be a safe alternative for patients with contraindications to aspirin.

Wound healing: a paradigm for lumen narrowing after arterial reconstruction

PURPOSE

The intimal hyperplasia hypothesis that equates lumen narrowing after arterial injury with intimal mass has recently been challenged. Evidence has emerged to suggest that lumen narrowing is caused in large part by changes in artery wall geometry rather than intimal mass per se. We have begun to explore this hypothesis in a unique nonhuman primate model of atherosclerosis.

METHODS

Monkeys who were fed an atherogenic diet for 3 to 5 years underwent experimental angioplasty of the left iliac artery. The contralateral iliac artery served as an intraanimal control. Arteries were removed 2, 4, 7, 14, 28, or 112 days later for analysis (6 or 13 per time point). Angioplasty dilated arteries by fracturing atheroma and stretching or tearing the media. Cross-sections of injured arteries were analyzed for expression of extracellular matrix components and cell surface integrins that are important in wound healing. Antibodies, riboprobes, or histochemical stains specific for fibrin, hyaluronan, versican (chondroitin sulfate-containing proteoglycan), procollagen-I, elastin, and the alpha 2 beta 1 and alpha V beta 3 integrins were used.

RESULTS

A thin mural thrombus was seen at sites of denudation and plaque fracture (days 2 to 7). This provisional matrix was invaded by leukocytes (days 2 to 4) and alpha-actin-positive smooth muscle cells (SMCs; days 4 to 7). Thrombus was replaced by SMCs expressing hyaluronan and the associated versican proteoglycans (day 14). Versican was expressed throughout the neointima as it enlarged (day 28), but expression later subsided (day 112). Procollagen-I expression initially increased in the adventitia (day 4) and then in the forming neointima (day 14). Procollagen-I expression was found to persist within the adventitia and in the neointima in SMCs nearest the lumen (days 28 to 112). Elastin staining was prominent within the mature neointima (day 112) but not at earlier time points. Integrin expression also increased within the injured artery wall. alpha v beta 3 staining (fibrin[ogen] receptor) increased in the injured media (days 2 to 7) and was then seen throughout the early neointima (day 7). Low level expression of alpha V beta 3 subsequently persisted within the forming neointima (day 28). alpha 2 beta 1 (collagen receptor) expression increased in the neointima in SMCs nearest the lumen (day 28).

CONCLUSIONS

Lumen narrowing after angioplasty in this model of atherosclerosis is caused largely by decreased artery wall diameter. The pattern of matrix and integrin expression within the injured artery wall is in many ways analogous to that of healing wounds. These observations suggest that tissue contraction may play a role in lumen narrowing at sites of arterial reconstruction. Strategies to inhibit wound contraction may prove effective in preventing restenosis.

[Pathophysiology and therapeutic concepts in coronary restenosis]

Demonstration of a reduced restenosis rate after stent implantation (Benestent, STRESS) has initiated rapid increase in stent implantation rates with widening indications. At present, the majority of stents are implanted in "none-Benestent/STRESS-lesions" with the consequence of a higher restenosis rate as previously expected. Stent restenosis has therefore become a relevant problem in interventional cardiology. In contrast to balloon angioplasty, where acute and subacute recoil represents the major mechanism of restenosis, stent restenosis is exclusively attributed to neointima proliferation. Morphological studies have demonstrated that neointima is caused by early smooth muscle cell ingrowth with a maximum after 7 days which is then gradually replaced by extracellular matrix. Systematic clinical, angiographic and intravascular ultrasound studies have identified several risk factors for increased stent restenosis such as: diabetes mellitus, treatment of restenosis, serial stent implantation, small and calcified vessels, ostial lesions, venous bypass grafts and complex stenosis morphology. In addition, there is increasing evidence that aggressive implantation techniques with high pressures and oversized balloons may also induce higher restenosis rates. Optimal treatment of instent restenosis has not been determined so far. Balloon angioplasty is at present considered the therapeutic option of choice. Several small studies have shown, that in short, discrete lesions (< 10 mm) results of simple PTCA are acceptable with re-restenosis rates between 15 and 35%. The intervention is considered safe with low complication rates. In 10 to 15% additional stent implantation is necessary, usually due to dissections proximal or distal to the treated stent. In long, diffuse stent restenosis (> or = 10 mm), however, PTCA results in high re-restenosis rates up to > 80%. This is most likely due to insufficient early balloon angioplasty results with minimal luminal diameters (MLD) significantly below the previous stent diameter. Therefore, debulking techniques have been used to reduce neointima burden within the stent. At present 3 techniques are available: directional coronary atherectomy (DCA), Excimerlaser angioplasty (ELCA) or high frequency rotablation. All of these techniques achieve a significant reduction in plaque volume within the stent and in combination with balloon angioplasty allow larger MLDs than PTCA alone. Limited experiences with ELCA and rotablation have shown that the techniques are safe without major periinterventional complications. DCA, however, has been accompanied with stent destruction and therefore should be considered with large care, especially in stents with coil design. At present, no randomized controlled trials for the comparison of debulking techniques with or without balloon angioplasty versus balloon angioplasty alone are available. Three multicenter trials have been initiated (LARS, ARTIST and TWISTER) to compare debulking techniques versus balloon angioplasty in diffuse stent restenosis. Adjunct medical treatment after interventions for stent restenosis is usually limited to ASS alone, indications for additional application of Ticlopidine have not been verified so far. Positive results are expected for the use of local radiation therapy either by radioactive stent implantation or afterloading techniques. With increasing stent implantation rates and indications, about 400,000 stents will be implanted in 1997 worldwide. Considering a low restenosis rate of 20%, 80,000 stent restenosis will occur within one year. Final recommendations for optimal treatment of these patients are not yet available.

Acute and 30-day results of the serpentine balloon expandable stent implantation in simple and complex coronary arterial narrowings

We report the acute and 30-day results with a new serpentine-design, tubular, stainless steel, balloon-expandable stent (beStent) in the first 100 patients. One hundred forty-eight stents were used to treat 103 narrowings in the left anterior descending (n = 46), left circumflex (n = 20), and right coronary (n = 37) arteries. There were 85 de novo and 18 restenotic lesions (lesion length: < 10 mm [31], 10 to 20 mm [43] > 20 mm [29]; lesion type: A [10] B1 [29], B2 [20], C [44]; total occlusions, 23. More than 1 stent was used in 31 patients for treatment of long lesions that could not be covered by 1 stent. The stents used were 15-mm (n = 106), 25-mm (n = 38), or 35-mm (n = 4) long. Stent implantation strategy involved predilatation, deployment, and high-pressure dilatation, using the same balloon if possible. Clinical in-hospital success was 97% (2 patients had stent thrombosis that was recanalyzed, with myocardial infarction developing in 1, and 1 patient died on day 14 from retroperitoneal bleeding treated with surgery and complicated by sepsis). One-month event-free survival was 96%, with 1 death on day 21 due to hypertensive crisis. There were no other major adverse cardiac events in this first complex cohort of patients. In conclusion, the initial experience with this stent demonstrates its safety and efficiency for treating simple and complex coronary disease, with a relatively low rate of complications. Long-term clinical follow-up awaits further investigation.

Coronary artery stenting in cardiac allograft vascular disease

Cardiac allograft vascular disease is characterized by diffuse and multifocal heterogeneous myointimal hyperplasia with or without vascular remodeling. Catheter-based interventions are indicated in selected patients. This study documents our experience with percutaneous transluminal coronary angioplasty and coronary stents (n = 48) in a group of 27 patients 5.7 +/- 2.9 years after heart transplantation. Early and intermediate results were controlled by angiography and intravascular ultrasound. Conventional percutaneous transluminal coronary angioplasty resulted in a mild and mostly inadequate gain in luminal dimensions (lumen area: 3.17 +/- 0.92 mm2 to 3.70 +/- 1.21 mm2; minimal lumen diameter: 1.84 +/- 0.23 mm to 2.04 +/- 0.36 mm). Coronary stenting led to a further improvement of luminal gain (lumen area: 3.70 +/- 1.21 mm2 to 5.86 +/- 1.76 mm2; minimal lumen diameter: 2.04 +/- 0.36 mm to 2.53 +/- 0.38 mm). These results were stabilized by application of aspirin and ticlopidine only. There were no stent thromboses or bleeding complications, and early hospital discharge of the patients was possible. At follow-up (mean follow-up period 7.72 +/- 5.45 months (range 0.50 to 23.13 months) all patients were clinically event free. In six of 24 stented vessels (25%) in 16 patients, significant restenosis (>50%) was found by intravascular ultrasound (n = 20) or by angiography (n = 4) 6 months after stent placement. We conclude that in eligible cardiac allograft vascular disease lesions primary stenting may be the method of choice. However, further evaluation of the modalities of stent application and different stent designs with respect to long-term survival is necessary.

Remodeling of human coronary arteries undergoing coronary angioplasty or atherectomy

BACKGROUND

Recently, long-term constriction of the vessel has been suggested as an alternative mechanism of restenosis after coronary angioplasty.

METHODS AND RESULTS

To understand remodeling of human coronary arteries undergoing coronary angioplasty or atherectomy, serial intravascular ultrasonographic examinations were performed at preintervention and postintervention examinations and at 24 hours, 1 month, and 6 months. Complete serial data were obtained in 61 lesions (balloon angioplasty, 35 lesions; directional atherectomy, 26 lesions). Lumen area improved from 6.81+/-2.24 mm2 after intervention to 8.22+/-2.79 mm2 at 1 month (P=.0001) and decreased to 4.88+/-2.86 mm2 at 6 months (P=.0001). Vessel area enlarged from 17.32+/-5.35 mm2 after intervention to 19.39+/-5.33 mm2 at 1 month (P=.0001) and decreased to 16.33+/-5.54 mm2 at 6 months (P=.0001). Plaque+media area increased significantly from postintervention examination to 24 hours (10.51+/-4.38 versus 10.96+/-4.49 mm2, P=.0008) and from 24 hours to 6 months (10.96+/-4.49 versus 11.45+/-4.45 mm2, P=.03). Changes in lumen area in each study interval correlated more closely with changes in vessel area than with changes in plaque+media area. Restenotic lesions compared with nonrestenotic lesions had a greater decrease in the vessel area between 1 month and 6 months (-4.33+/-2.73 versus -2.49+/-2.15 mm2, P=.006) and greater increase in the plaque+media area both within 24 hours (0.84+/-1.22 versus 0.27+/-0.38 mm2, P=.04) and between 24 hours and 6 months (1.19+/-2.19 versus 0.18+/-1.46 mm2, P=.04). CONCLUSIONS; Remodeling after coronary angioplasty or atherectomy was characterized by early adaptive enlargement and late constriction of the vessel.

Late regression of the dilated site after coronary angioplasty: a 5-year quantitative angiographic study

BACKGROUND

Limited data are available on the changes that occur at the dilated site late after coronary angioplasty. The aim of this study was to evaluate with quantitative angiography the natural history of changes that occur in the dilated segment between "early" (approximately 6 months) and "late" (approximately 5 years) follow-up after angioplasty.

METHODS AND RESULTS

Of 127 consecutive patients (174 lesions) with successful angioplasty, 125 underwent early angiography. Three patients subsequently died, and 24 underwent revascularization surgery or repeated angioplasty, giving a study-eligible population of 98 patients. Quantitative angiographic analysis was performed before and immediately after angioplasty and at early and late follow-up in the study population of 84 patients (115 lesions), which was 86% of study-eligible patients. Mean lesion diameter stenosis decreased from 36.3+/-14.2% at early to 29.6+/-13.5% at late follow-up (P<.0001). No lesion developed late restenosis by the 50% diameter loss criterion. Late regression was related to stenosis severity at early angiography (r=-.58, P<.001). Subgroups at early angiography of 40% to 49% stenosis and > or = 50% stenosis showed significant regression at late angiography.

CONCLUSIONS

Lesion regression at the dilated site is common late after angioplasty. The more severe a stenosis is at early angiography, the more likely the chance that there will be late regression. A strategy of watchful waiting may be appropriate for patients with restenotic lesions of borderline severity.

Long-term clinical follow-up after successful repeat percutaneous intervention for stent restenosis

OBJECTIVES

This study evaluated the long-term clinical outcome of successful repeat percutaneous intervention after in-stent restenosis.

BACKGROUND

Recurrence of symptoms and angiographic restenosis after stent implantation are observed in 15% to 35% of cases. Repeat percutaneous treatment for in-stent restenosis has been shown to be safe, with high immediate success, but little is known about the long-term clinical outcome.

METHODS

Clinical follow-up (minimum 9 months) was obtained in a consecutive series of 124 patients (127 vessels) presenting with stent restenosis who were successfully treated with repeat percutaneous intervention.

RESULTS

Clinical follow-up was obtained in all 124 patients at a mean [+/-SD] of 27.4 +/- 14.7 months (range 9 to 66); a stress test was available in 88 patients (71%). Recurrence of clinical events occurred in 25 patients (20%) and included death from any cause in 2 patients (2%), target vessel revascularization in 14 (11%), myocardial infarction in 1 (1%) and positive stress test results or recurrence of symptoms (Canadian Cardiovascular Society class I to IV) treated medically in 8 (6%). Cumulative event-free survival at 12 and 24 months was 86.2% and 80.7%, respectively. Significant predictive factors of recurrence of clinical events were repeat intervention in saphenous vein grafts, multivessel disease, low ejection fraction and a < or = 3-month interval between stent implantation and repeat intervention.

CONCLUSIONS

In-stent balloon angioplasty for stent restenosis in native vessels seems to be an effective method in terms of a low long-term clinical event rate.

One-week and six-month angiographic controls of stent implantation after occlusive and nonocclusive dissection during primary balloon angioplasty for acute myocardial infarction

We prospectively assessed in 124 consecutive patients by means of 1-week and 6-month follow-up angiograms the rate of reocclusion and restenosis of coronary stenting with Palmaz-Schatz stents after occlusive and nonocclusive dissection during primary balloon angioplasty for acute myocardial infarction (AMI). Patients were further evaluated clinically at 1 year. Stenting was performed on large (>3.2 mm) coronary arteries for suboptimal results (47%), occlusive (8%), or nonocclusive dissections (45%) after balloon angioplasty. Stents were delivered using the bare stent technique and high pressure inflations (>12 atm). All patients received ticlopidine 250 mg (500 mg if weight was >80 kg) and aspirin 100 mg for 1 month. No patient received warfarin. At 1 week, 6 patients died of cardiogenic shock and 2 of right ventricular infarction. One subacute occlusion occurred at day 14. At 6 months, in 95 patients, the angiographic restenosis rate (>50% diameter stenosis) was 19%. One-year clinical follow-up, available in 55 patients, indicated cardiac death in 5, and repeat revascularization in 3. Thus, coronary stenting on large (>3.2 mm) coronary arteries after occlusive and nonocclusive dissection during primary balloon angioplasty for AMI using bare Palmaz-Schatz stents, high pressures, ticlopidine, and aspirin is safe. Our reocclusion and restenosis rates are similar to those of trials on elective stenting in stable patients.

Clinical one-year outcomes after stenting in acute myocardial infarction

We retrospectively review our results of 96 stent placements in 64 patients identified from our data base who received stents acutely and within 48 hr of acute myocardial infarction. The average age was 60 years; 77% were male. The average length of stay was 6.75 days. Three patients needed coronary artery bypass grafting (CABG) before discharge: 2 for stent occlusion and 1 for papillary muscle rupture. Need for CABG, further percutaneous transluminal coronary angioplasty (PTCA), myocardial infarction, and death defined outcome. Mean patient follow-up was 10.3 (+/-5.3) months. Seventy-two percent of patients were free of outcome events at 1 year, 17% needed CABG, and 11% required further PTCA. There were 2 myocardial infarctions and 1 death. Presence of left bundle branch block on admission electrocardiogram and angina in hospital after stent placement predicted worse outcome (P < 0.01).

Clinical and angiographic implications of coronary stenting in thrombus-containing lesions

OBJECTIVES

This study sought to determine the results of coronary stenting in thrombus-laden lesions.

BACKGROUND

The angiographic evidence of intracoronary thrombus has classically been considered a formal contraindication to stent implantation. However, with increasing use of stenting, the indications for this technique have widened to include treatment of patients who have an acute coronary syndrome or lesions with adverse anatomic features.

METHODS

We studied 86 consecutive patients (mean age +/- SD 61 +/- 11 years, 14 women) undergoing coronary stenting of a thrombus-containing lesion; the procedure was performed electively in 39% and after angioplasty failure in 61%. Sixty-four patients (75%) were treated for unstable angina, and 19 (22%) underwent the procedure during an acute myocardial infarction. A specific protocol that included clinical and late angiographic follow-up was used.

RESULTS

Angiographic success was obtained in 83 patients (96%). Five patients (6%) died during the hospital stay despite angiographic success; four of these had cardiogenic shock, and one (1%) had subacute stent thrombosis. Non-Q wave myocardial infarction developed in five additional patients (6%), and four of these five had data consistent with distal embolization. Of the 78 patients discharged with angiographic success, 67 (86%) were event-free and clinically improved at last follow-up visit (12 +/- 11 months). During the follow-up period, eight patients required repeat angioplasty, one patient required heart transplantation, and two patients died. Quantitative angiography demonstrated excellent angiographic results after stenting (minimal lumen diameter 0.31 +/- 0.4 vs. 2.77 +/- 0.6 mm). Late angiographic follow-up (5.5 +/- 1 months) was obtained in 50 patients with 54 lesions (93% of eligible), revealing a minimal lumen diameter of 2.0 +/- 1 mm and restenosis (lumen narrowing > 50%) in 18 lesions (33%).

CONCLUSIONS

Coronary stenting constitutes an effective therapeutic strategy for patients with thrombus-containing lesions, either after failure of initial angioplasty or electively as the primary procedure. Coronary stenting in this adverse anatomic setting results in a high degree of angiographic success, a low incidence of subacute thrombosis and an acceptable restenosis rate.

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

OBJECTIVES

We sought to evaluate the immediate angiographic results and intermediate-term follow-up after percutaneous treatment of left main coronary stenoses in the new device era.

BACKGROUND

Historically, balloon angioplasty of left main coronary stenoses has been associated with high procedural morbidity and poor long-term results. It is not clear whether new devices are more effective in this anatomic setting.

METHODS

Between July 1993 and July 1995, we performed initial left main coronary interventions on 46 patients (mean age 67 +/- 12 years, 26% women). Quantitative angiography was available for 42 of 46 interventions, and clinical follow-up was obtained for all patients at 1 month, 6 months and 1 year after initial revascularization.

RESULTS

Most interventions (42 of 46) were performed in patients with "protected" coronary stenoses to the left coronary system owing to the presence of one or more patent left main coronary grafts. Seventy-seven percent of screened patients were deemed unsuitable for repeat coronary artery bypass surgery. Procedures performed included stenting in 73% of patients (alone in 30% and after rotational atherectomy in 43%), rotational atherectomy in 58% (alone in 15% and before stenting in 43%), directional atherectomy in 4% and angioplasty alone in 7%. Initial procedural success was achieved in all interventions, with no deaths, myocardial infarctions (creatine kinase, MB fraction > 50 IU/liter) or emergent bypass surgery. Follow-up data to date (median duration 9 months, range 6 to 19) demonstrate a 98% overall survival rate and a 6-month event-free survival rate of 78% (six target vessel revascularizations [TVRs], four non-TVRs).

CONCLUSIONS

Treatment of protected left main coronary artery stenoses can be accomplished safely and effectively with new device technology. Intermediate-term follow-up demonstrates an acceptably low rate of death, myocardial infarction or repeat revascularization at 6 months and 1 year.

Recent progress in coronary interventions--assessment by quantitative coronary angiography

Coronary balloon angioplasty is now well accepted as an effective therapy for patients with significant coronary artery stenosis. However, a number of deficiencies, including short-term complications, long-term restenosis, and limited application to complex morphologic lesions, restrict the widespread use of this technique. The precise lesion measurement provided by quantitative coronary angiography and intracoronary ultrasonography is a prerequisite for the optimization of balloon dilation or stent implantation. The short-term outcome may be improved by stent implantation, as this can prevent acute closure by acting as a scaffold for the disrupted vessel wall. The indications for percutaneous revascularization have been extended to chronic total occlusion by using a special guidewire, a laser wire and a coronary stent. Local drug delivery techniques to distribute agents to target revascularization sites may play a role in reducing the restenosis rate. Although the limitations of balloon angioplasty have led to the introduction of new devices, it remains to be seen whether these new devices can demonstrate, in a scientific manner, their safety, feasibility and superiority over conventional balloon angioplasty. Percutaneous coronary revascularization therapy may be an acceptable alternative to coronary bypass surgery in the future. However, to confirm this, a large multicenter randomized study is necessary to compare new percutaneous coronary interventional devices with bypass surgery. Additionally, further studies are required to demonstrate the most effective device for treating specific lesions in each individual patient.

One balloon, one stent: an effective cost-containment strategy for elective stent deployment

A cost-containment strategy to reduce stent procedure-related resources utilizing an integrated system comprised of a Stablizer guide wire, a Brite-Tip guiding catheter, and a single Titan balloon catheter for both lesion predilatation and poststent deployment was compared to a conventional strategy utilizing a nonintegrated guide wire, guiding catheter, and balloon components. Both groups were comparable with respect to demographics, number of lesions stented, and stents deployed per lesion. No differences in lesion length or pre- and poststent minimal luminal diameter were observed. Balloon use was significantly reduced using the integrated strategy when compared to the conventional strategy (1.3 +/- 0.5 vs. 2.1 +/- 1.1; P < 0.01); overall nonstent-related resource utilization was significantly reduced ($747 +/- $401 vs. $1,093 +/- $467; P < 0.01). Procedural success rates were identical in both groups (100%), and no patient sustained subacute stent thrombosis or required target vessel revascularization at 1 mo follow-up. We conclude that the use of a single Titan balloon catheter as part of an integrated cost-containment strategy for both lesion predilatation and poststent deployment results in considerable cost savings while maintaining high procedural and clinical success rates.

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

OBJECTIVES

The purpose of this prospective single-center study was to evaluate the longer-term outcome of Palmaz-Schatz stenting in the treatment of native coronary and saphenous vein bypass graft disease.

BACKGROUND

The STRESS (Stent Restenosis Study) and BENESTENT (Belgian Netherlands Stent) trials have demonstrated a decrease in both angiographic restenosis and the need for repeat revascularization in the 1st year for vessels treated by stenting rather than balloon angioplasty. Longer-term (1 to 5 years) clinical results of Palmaz-Schatz stenting are not yet well established. Late migration of the stent, metal fatigue, endarteritis and late restenosis have all been proposed as potential late clinical complications of coronary stent implantation.

METHODS

The study cohort consisted of 175 consecutive patients who underwent elective placement of 194 Palmaz-Schatz stents in 185 vessels. Clinical events (death, myocardial infarction, recurrent angina or any revascularization) were assessed at 6 weeks, 2, 4 and 6 months, 1 year and yearly thereafter. Clinical follow-up was available on all patients at a mean +/- SD of 54 +/- 17 months.

RESULTS

Angiographic success was achieved in 173 patients (98.9%); angiographic restenosis was observed at 6 months in 26.1% of target sites. The survival rate was 86.7% at 5 years, with a 5-year event-free survival rate decreasing progressively to 50.7%, reflecting primarily repeat revascularization procedures (41.2% at 5 years). However, the rate of repeat revascularization of the treatment site (target site revascularization [TSR]) was 14.4%, 17.7% and 19.8% at 1, 3 and 5 years, respectively, with late (> 1 year) TSR driven by in-stent restenosis in only 3 patients (1.7%). Rates of both 5-year survival (70.5% vs. 93.4%) and event-free survival (21.1% vs. 63.3%) were lower for patients who underwent saphenous vein graft (SVG) stenting than for those with native coronary artery stenting. However, 5-year TSR rates were similar for SVGs (21.9%) and native vessels (19.2%), indicating that the higher incidence of repeat revascularization for SVGs was due to an increase in non-TSR, driven by progressive disease at other sites.

CONCLUSIONS

The long-term outcome of stenting shows stability of the treated lesion, with only a slight increase in TSR between 2 and 5 years (17.1% to 19.8%). The progressive increase in repeat revascularization over that period (24% to 41%) and most ongoing late events can be attributed to the progression of coronary disease at other sites, rather than to late deterioration of the stent result itself. Such non-TSR events account for the majority of clinical events in the patients who underwent SVG stenting.

Coronary artery stenting: indications and cost implications

The practice of coronary stenting is evolving rapidly, with new stent designs, deployment techniques, and adjunctive therapy. In many respects, clinical practice is changing in advance of the availability of supporting data. The consistent excellent angiographic result with stent deployment exceeds that achieved by any other previous interventional device, and the extent to which this accounts for the exponential increase in stent utilization cannot be accurately determined but is undoubtedly considerable. Controlled randomized trials have confirmed that stent deployment is superior to balloon angioplasty in certain lesion subsets or clinical scenarios. These include focal de novo native vessel lesions, lesions with late recoil after balloon angioplasty, acute closure after balloon angioplasty, and proximal left anterior descending coronary artery lesions. In addition, observational data is persuasive in focal coronary saphenous vein graft lesions and aorto-ostial lesions. On the other hand, the evidence supporting the use of stents strictly to improve on a suboptimal result, possibly the most frequent indication, is indirect and circumstantial. Stents are expensive, but it was anticipated that with the reduction in restenosis not only would they be cost-effective but also ultimately would reduce costs. This hope has not as yet been realized. However, there is little question that the introduction of intracoronary stents has been the most significant and exciting development since the introduction of percutaneous revascularization almost 20 years ago. It has revitalized the field.

Effect of polytetrafluoroethylene covering of Palmaz stents on the development of intimal hyperplasia in human iliac arteries

PURPOSE

The occurrence of neointimal hyperplasia within a stent may result in restenosis with recurrent symptoms of end-organ ischemia. This study evaluated the potential of a nonporous covering of a stent to function as a barrier to the formation of intrastent neointimal hyperplasia.

MATERIALS AND METHODS

Twelve endovascular stent grafts were used to treat 12 high-risk patients with limb-threatening ischemia secondary to long-segment iliac artery occlusion. A 6-mm, thin-walled polytetrafluoroethylene graft was inserted and anchored to the common iliac artery with use of Palmaz stents. Each stent was covered by graft material over one-half of its length. Control angiograms obtained immediately after graft insertion were compared with follow-up angiograms obtained between 4 and 6 months after the initial procedure. On each angiogram, the region of the stent was magnified by 20x to permit computerized luminal diameter measurements.

RESULTS

The mean luminal diameter within the stent was significantly greater on the covered (7.7 mm +/- 0.33 standard deviation) compared with the uncovered (6.7 mm +/- 0.85 standard deviation) portions (P < .01).

CONCLUSIONS

Partially covered stents are a unique model for assessing the effects of an extrinsic stent covering on arterial healing and myointimal hyperplasia. These data suggest that a relatively nonporous covering of polytetrafluoroethylene may inhibit stent-related restenosis in iliac arteries.

Gastric perforation in the neonate: clinical analysis of 12 cases

Gastric perforation is a rare abdominal catastrophe which associated with high mortality in newborn infants. From June 1978 to July 1991, twelve cases of neonatal gastric perforation presented at Chang Gung Memorial Hospital. Male to female ratio was 9:3. The most common presenting signs were abdominal distension (100%), feeding intolerance (92%), respiratory distress (67%) and poor activity (58%). All cases had significant symptoms between two and five days of age. All of the abdominal plain film showed pneumoperitonium. The most common site of perforation was the great curvature of the stomach (83%). Among the 10 pathological reports available, 8 cases had ischemic change and 2 cases had hemorrhage and inflammatory cell infiltration. There was a high mortality rate of 58% in this series. Male, hyponatremia (serum sodium < 130 meq/l) and metabolic acidosis (pH < 7.3) were poor prognostic factors. This report suggests that early diagnosis and early management before clinical deterioration of the metabolic status may improve prognosis for neonatal gastric perforation patients.