A randomized, double-blind, placebo-controlled trial of abciximab for prevention of in-stent restenosis in diabetic patients after coronary stenting: results of the ASIAD (Abciximab in Stenting Inhibits restenosis Among Diabetics) Trial

OBJECTIVES

Coronary stenting is associated with a high incidence of restenosis in patients with diabetes mellitus. Recent data suggest that diabetic patients treated with abciximab have a lower rate of target vessel revascularization (TVR). We sought to investigate whether abciximab can reduce in-stent restenosis after coronary stenting in diabetic patients.

METHODS

In this prospective double-blind trial, we randomly assigned 254 patients with type 2 diabetes mellitus undergoing nonurgent coronary stenting to receive abciximab with an initial heparin bolus of 50 U/kg (n = 128) or placebo with an initial heparin bolus of 70 U/kg (n = 126). All patients received aspirin and clopidogrel before the procedure. The primary endpoint was angiographic restenosis by quantitative coronary angiography at 6 months. The secondary endpoint was death, myocardial infarction (MI), or target lesion revascularization (TLR) at 6 months.

RESULTS

The clinical, angiographic, and procedural characteristics were matched between the 2 groups. Angiographic follow-up was completed in 226 patients (90%). Angiographic restenosis occurred in 29.1% of the abciximab group, and 24% of the placebo group (p = 0.30). The rates of the secondary endpoint were similar between the 2 groups (23.4% in the abciximab group versus 22.2% in the placebo group; p = 0.88). TLR was performed on 36 (18.4%) lesions in 29 (23.4%) patients of the abciximab group, and 26 (13.6%) lesions in 23 (18.3%) patients of the placebo groups, respectively (p = 0.21 and 0.35, respectively).

CONCLUSIONS

Abciximab does not reduce angiographic restenosis or TLR in type 2 diabetic patients undergoing nonurgent coronary stenting.

Delayed occurrence of restenosis in drug eluting stents: an evidence of delayed healing

Drug eluting stents have made a significant impact on restenosis. However, there are concerns regarding delayed "catch-up" of restenosis. In this case report we present two such patients with delayed occurrence of restenosis after drug eluting stent implantation.

Management of acute myocardial infarction--primary angioplasty the treatment of choice!

The management goal of acute myocardial infarction is prompt revascularization. Recent years have seen improvements in both pharmacological and mechanical methods of revascularization of the infarct related arteries. This brief review summarises these developments and ongoing efforts.

Mahaim automatic accelerated rhythm: a marker of successful radiofrequency ablation

BACKGROUND

Mahaim pathways are characterized by the presence of an accessory pathway potential-the 'M' potential, at the tricuspid annulus. M potential is a very useful guide during radiofrequency ablation of Mahaim pathway. During ablation, an accelerated rhythm with ORS morphology, identical to fully pre-excited QRS complex is observed, and has been labeled as Mahaim automatic rhythm. We analyzed this rhythm during radiofrequency ablation of these pathways.

METHODS AND RESULTS

Eighteen patients with Mahaim accessory pathways were taken up for electrophysiology study and radiofrequency ablation. Tricuspid annulus was mapped for 'M' potentials and targeted for ablation. Duration of ablation and number of ablation attempts were guided by Mahaim automatic rhythm during ablation. Mahaim tachycardia was inducible in all. 'M' potentials were recorded in 15/18 patients. Radiofrequency energy was delivered at the site where Mahaim accelerated rhythm was noticed and was continued till abolition of the rhythm. This resulted in long-term success. In 3 patients, M potentials were not recordable, and in them other methods including 3-dimensional electroanatomical mapping was also not successful.

CONCLUSIONS

'M' potential-guided radiofrequency ablation is a useful technique. Presence of Mahaim automatic rhythm and its abolition during ablation is associated with long-term success of the procedure.

The NUGGET study: NIR ultra gold-gilded equivalency trial

This study should clarify whether the gold-coated NIROYAL stent is equivalent to the stainless steel NIR stent. Patients were randomized to either NIR stent (n = 298) or a NIROYAL stent (n = 305). The primary endpoint was the minimum lumen diameter of the target lesion at 6 months postprocedure. Secondary endpoints focused on clinical events. At 30 days, adverse events were similar in both groups. At 6 months, the minimal lumen diameter was 1.83/1.64 mm (P < 0.001; 95% CI = 0.08-0.30) and the angiographic restenosis rate was 20.6%/37.7% (P < 0.001; 95% CI = -24.7 to -9.3) for NIR/NIROYAL. The 6-month MACE rates were NIR 7.4% and NIROYAL 10.5% (95% CI = -7.7 to 1.4). Compared to stainless steel stent, the NIROYAL stent demonstrated a smaller minimal lumen diameter, a higher late loss (i.e., higher neointimal hyperplasia in spite of a significantly better initial gain), with higher restenosis and similar MACE rates at 6 months.

Pace mapping for the localization of focal atrial tachycardia arising near the mitral annulus

Of the various therapeutic modalities available to treat ectopic atrial tachycardia, radiofrequency catheter ablation has shown excellent results. It is usually possible to localize the earliest site of endocardial activation by conventional or newer three-dimensional mapping techniques. We report a case of ectopic atrial tachycardia, wherein the tachycardia was being repeatedly interrupted by mechanical trauma. Finally, with the help of P wave pace mapping, the tachycardia was localized near the posterolateral part of the mitral annulus, and successfully ablated. This report demonstrates the utility of P wave pace mapping in ectopic atrial tachycardia.

Left atrial-coronary sinus dissociation following an attempt at radiofrequency ablation for a left lateral accessory pathway

Coronary sinus electrograms generally represent the sequence of left atrial activation, and are very helpful in localizing and differentiating left lateral accessory pathway-mediated tachycardia from other supraventricular tachycardias. The activation of the coronary sinus from the left atrium occurs through muscle bridges, which may be discrete or form an intermingled continuum. These muscle bridges, if disconnected, may dissociate the coronary sinus from the left atrium, in which case the coronary sinus electrograms do not represent left atrial activation, and do not help to understand, or may cause misinterpretation of, the mechanism of supraventricular tachycardia. We report one such case of orthodromic supraventricular tachycardia mediated through the left lateral accessory pathway in which the coronary sinus got dissociated from the left atrium during radiofrequency ablation.

Platelet glycoprotein IIb/IIIa inhibition using eptifibatide with primary coronary stenting for acute myocardial infarction: a 30-day follow-up study

The results of primary coronary stenting for acute myocardial infarction (AMI) have been reported to improve significantly with the concomitant administration of platelet glycoprotein IIb/IIIa inhibitor abciximab. There are, however, no data available with the use of eptifibatide, a more cost-effective, small-molecule GP IIb/IIIa blocker with a shorter half-life. In a prospective multicenter feasibility and efficacy study, we assigned 55 consecutive patients with AMI being taken up for primary stenting to receive eptifibatide just before the procedure (two boluses of 180 microg/kg 10 min apart and a 24-hr infusion of 2 microg/kg/min). Clinical outcomes were evaluated at 30 days after the procedure. The angiographic patency of the vessel with TIMI flow rates, TIMI myocardial perfusion (TMP) grade, and corrected TIMI frame counts were assessed at the end of procedure and before hospital discharge. At 30 days, the primary endpoint, a composite of death, myocardial infarction, and urgent target vessel revascularization (TVR) was seen in 12.7% of patients. The TIMI 3 and TMP grade 3 flow, which was seen in 93% and 86% of patient, respectively, at the end of the procedure, declined to 86% and 78%, respectively (P < 0.05) before hospital discharge. Corrected TIMI frame counts also decreased from 25.7 +/- 7.2 to 22.9 +/- 6.8 (P < 0.05). There were five (9.1%) instances of subacute thrombosis (SAT) presenting as AMI, needing urgent TVR in all, within 3-5 days of the primary procedure. No excessive bleeding complication, directly attributable to the use of eptifibatide, was observed. The study was terminated prematurely because of an unacceptable SAT rate. Administration of eptifibatide along with primary stenting for AMI is associated with a high TIMI 3 and TMP grade 3 flow acutely. However, these flows decline significantly before hospital discharge and lead to a high rate of SAT. The dosage and duration of infusion of eptifibatide in this setting needs further evaluation.

Sildenafil in the management of primary pulmonary hypertension

Primary pulmonary hypertension is a rare disorder of unknown etiology with a poor prognosis. There is no cure, and drug therapy is effective in only a few patients. Calcium-channel antagonists and anticoagulants are the mainstay of therapy. Prostacyclin therapy leads to significant clinical improvement but its use is restricted due to high cost and complex drug delivery systems. Sildenafil is a selective vasodilator and has been shown to be effective in decreasing pulmonary vascular resistance in animal models of pulmonary hypertension. We report the use of sildenafil in two patients of primary pulmonary hypertension who were refractory to conventional drug therapy.

Chronic atrial fibrillation in patients with rheumatic heart disease: mapping and radiofrequency ablation of flutter circuits seen at initiation after cardioversion

BACKGROUND

There is little information concerning mapping and radiofrequency ablation (RFA) of arrhythmias seen during reinduction of atrial fibrillation (AF) after pharmacological and/or electrical cardioversion in patients with chronic AF and rheumatic heart disease.

METHODS AND RESULTS

Seventeen patients with rheumatic heart disease and symptomatic chronic AF underwent multisite atrial mapping during reinduction of AF after cardioversion. An organized atrial arrhythmia of varying duration was seen to precede the AF in all patients. The earliest atrial activity during this organized rhythm was near the coronary sinus ostium (CS OS) in 14 patients and along the left side of the interatrial septum (IAS) in 3 patients. RFA was performed in 16 patients (14 near the CS OS and 2 along the IAS). Postablation AF was inducible in 1 patient in whom RFA was preformed near the CS OS and in both patients when it was performed along the IAS. At a follow-up of 6 to 56 weeks (mean, 32 weeks), 10 of the 13 patients who had successful ablation were in sinus rhythm. All patients in whom AF was reinducible immediately after RFA continue to be in AF.

CONCLUSIONS

Induced AF in patients with rheumatic heart disease begins as a rapid organized arrhythmia with earliest atrial activity near the CS OS in most patients. RFA targeting the region of the CS OS is successful in suppressing the arrhythmia immediately in most of the patients and in most on follow-up.

Intravascular low-power laser irradiation after coronary stenting: long-term follow-up

BACKGROUND AND OBJECTIVE

A high restenosis rate remains a limiting factor for percutaneous transluminal coronary angioplasty and stenting. The objective of this study was to evaluate the effect of intravascular red laser therapy (IRLT) on restenosis after stenting procedures in de novo lesions.

STUDY DESIGN/MATERIALS AND METHODS

A total of 68 consecutive patients were treated with IRLT in conjunction with coronary stenting procedures. Mean lesion length was 16.5 +/- 2.4 mm. Reference vessel diameter (RVD) and pre-minimal lumen diameter (MLD) were 2.90 +/- 0.15 mm and 1.12 +/- 0.26 mm, respectively.

RESULTS

After treatment, MLD was 2.76 +/- 0.32 mm with no procedural complications or in-hospital adverse events. Angiographic follow-up (n = 61) revealed restenosis in nine patients (14.7%) with rate by artery size of > 3 mm (n = 21) 0%; 2.5--3.0 mm (n = 28) 14.2%; and < 2.5 mm (n = 12) 41.6%.

CONCLUSION

Intravascular red light therapy is safe, feasible, and reduces expected restenosis rate after coronary stenting.

Coronary stent implantation without lesion predilatation (direct stenting): our experience with this evolving technique

BACKGROUND

Until recently, conventional intracoronary stent deployment required predilatation of the lesion with a balloon. However, "direct stenting" of the lesion without predilatation offers certain theoretical and practical advantages. We assessed the safety and feasibility of direct stenting in a select group of patients who were likely to benefit most from these advantages, namely, those with acute coronary syndromes. saphenous vein graft lesions, associated renal or left ventricular dysfunction and those requiring multivessel intervention.

METHODS AND RESULTS

After direct stenting, intravascular ultrasound was used to assess the adequacy of stent expansion in 51 patients. One hundred and twenty patients with a total of 125 lesions (83.3% males, average age 54.6+/-12.4 years) were enrolled for direct stenting. Of these, 90% of patients had presented with acute coronary syndromes, 21.6% of patients had associated moderate-to-severe left ventricular systolic dysfunction, 6.7% of patients had associated renal dysfunction and 30.8% of patients required multivessel intervention. Angiographically visible thrombus was present in 35.2% of patients. The mean reference diameter of the lesion was 3.18+/-0.32 mm and mean percentage diameter stenosis was 76.4+/-11.2%. Almost all varieties of stents were used (8.8% bare and 91.2% mounted). Procedural success was achieved in 98.3% of patients (98.4% of lesions). In two cases, the lesion had to be predilated prior to stenting. On angiography, the need for postdilatation of the stent was apparent in 29 (23.6%) lesions. In contrast, on intravascular ultrasound evaluation done in 51 lesions after stent deployment, the need for postdilatation to optimize stent expansion was seen in 43 (84.3%) lesions. There was one instance of acute stent thrombosis and two instances of slow-flow phenomenon. There were no deaths, myocardial infarction or need for urgent bypass surgery.

CONCLUSIONS

We conclude that direct stenting is feasible and safe in selected groups of patients. Optimization of stent expansion after direct stenting may often require aggressive postdilatation.

Management of chronic stable angina pectoris from a sceptic's view point

Ischaemic heart disease is a leading cause of death in the world. It has clinically defined phases as: Asymptomatic, stable angina, progressive angina and unstable angina. It is important to differentiate patients of angina into those with stable and unstable angina--risk stratification and management differ in the two groups. Risk stratification of patients with stable angina using clinical parameters helps in development of clearer indication of referral for exercise testing and cardiac catheterisation. Chronic stable angina patients with history of documented myocardial infarction of Q waves on ECG should have measurement of left ventricular systolic function (ie, ejection fraction) as it is important for choosing the appropriate medical or surgical therapy. Symptomatic patients with suspected or known coronary artery disease should usually undergo exercise testing to assess the risk of future cardiac events. The treatment of stable angina has two purposes: To prevent myocardial infarction and death and therapy directed towards preventing death. Pharmacotherapy consists of: Aspirin, lipid lowering agents, beta-blockers, nitrates, short acting dihydropyridine calcium antagonists, etc. For surgery, there are two well established approaches of revascularisation. One is coronary artery by-pass grafting and the other is percutaneous transluminal coronary angioplasty. Studies comparing different treatment modalities are elaborated in this article. In conclusion, it can be said that patients having severe symptoms affecting quality of life despite optimal medical therapy should be referred for revascularisation surgery.

Long-term follow-up after coronary stenting and intravascular red laser therapy

A high restenosis rate remains a limiting factor for coronary angioplasty and stenting. Recently, use of intravascular red light therapy (IRLT) has been shown to be effective in different animal models and in humans in reducing the restenosis rate. Sixty-eight patients were treated with IRLT in conjunction with coronary stenting procedures. Mean age was 64 +/- 9 years. Treated lesions were type A (11), type B (42), and type C (18) with a mean lesion length of 16.5 +/- 2.4 mm. Reference vessel diameter and minimal lumen diameter (MLD) before therapy were 2.90 +/- 0.15 and 1.12 +/- 0.36 mm, respectively. After stenting and laser irradiation, MLD was 2.76 +/- 0.39 mm. No procedural complications or in-hospital adverse events occurred. All patients were followed up as depicted in the protocol. Sixty-one patients underwent angiographic restudy, which revealed restenosis in 9 patients (14.7%). Observed restenosis rate by artery size was > 3 mm (n = 21, 0%), 2.5 to 3.0 mm (n = 28, 14.2%), and <2.5 mm (n = 12, 41.6%). We conclude that IRLT is safe and feasible and reduces the expected restenosis rate in patients after coronary stenting in arteries of >2.5 mm.

Recording of double atrial potentials as a marker for isthmus block during ablation of atrial flutter

Radiofrequency ablation is an established method for treatment of type I atrial flutter. The assessment of creation of complete bidirectional isthmus block following linear ablation of the isthmus is an integral part of ablation procedure. Conventionally, bidirectional isthmus block is tested by pacing on either side of ablation line and looking for reversal of activation sequence in the right atrium. We looked at the feasibility of recording double potentials, separated by an isoelectric interval along the ablation line as an alternative method to demonstrate bidirectional isthmus block. An attempt was made to record the double potentials following linear ablation of the cavotricuspid isthmus. Following ablation, bidirectional isthmus block was also tested by pacing from the coronary sinus os and the low-lateral right atrium. We could demonstrate double potentials in 9 of the 11 patients in whom we attempted to record them following linear ablation of flutter. The presence of bidirectional block by pacing from coronary sinus os and low lateral right atrium could be demonstrated in 10 (91%) patients. Thus, double atrial potentials, separated by an isoelectric interval can be demonstrated following ablation of atrial flutter. Double potentials, if demonstrable on coronary sinus os and low lateral right atrium pacing, could serve as an alternative marker of isthmus block.

Coronary stent thrombosis: time course and clinical outcome

The current clinical practice of stent implantation has changed over the last few years. We analysed the incidence and time course of stent thrombosis in patients undergoing successful coronary angioplasty and stenting over the last three years. All the patients were treated with aspirin and ticlopidine. A total of 13 patients experienced stent thrombosis. The mean age was 52+/-12 years; 12 were smokers and 10 had a recent history of myocardial infarction. None of these patients had received abciximab. The median time from stent implantation to stent thrombosis was 10 hours, with all the stent occlusions occurring within 18 hours of stent implantation procedure. All the patients underwent a repeat intervention at a median time of 30 minutes after the clinical suspicion of stent occlusion. On follow-up of 1 to 24 months, three patients developed reocclusion. In the present era of coronary angioplasty and stenting, when interventional procedures are not pre-planned and patients are treated with aspirin and ticlopidine or clopidogrel at the time of stent implantation, the incidence of stent thrombosis is low; it is seen mainly in patients with recent myocardial infarction, majority of them being smokers, and occurs within 18 hours in all the patients.

Multi-vessel coronary stenting--procedural results and late clinical outcomes: a comparison with single-vessel stenting

The purpose of this study was to assess the 1-year clinical outcome of patients with multi-vessel coronary artery disease (CAD) who underwent coronary stenting, and to compare the results with single-vessel coronary stenting carried out during the same period. We evaluated the in-hospital and 12-month clinical outcomes [death, Q-wave myocardial infarction (MI) and repeat revascularization rates at one year] in 384 consecutive patients treated with coronary stents in 2 (92% of patients) or 3 of the native coronary arteries and compared the outcome to 624 consecutive patients undergoing stenting in a single coronary artery between January 1, 1997 and January 31, 1999. The overall procedural success was obtained in 99% of patients with 2- or 3-vessel stenting and 98% of patients with single-vessel stenting. Procedural complications were similar (2.9% vs 2.6%; p = 0.12). During follow-up, target lesion revascularization was 16% in multi-vessel and 14% in single-vessel stenting (p = 0.38) and repeat revascularization was also similar for both groups (19% vs. 20%; p = 0.73). There was no difference in death (0.8% vs. 1.3%; p = 0.31) and Q-wave MI (0.7% vs. 1.4%; p = 0. 16) in the 2 groups. Overall cardiac event-free survival was similar for both groups (76% vs. 78%; p = 0.54). Multi-vessel stenting in carefully selected patients in our experience had a high procedural success with very low complication rates. The one-year clinical outcomes were acceptable and were similar to the results of single-vessel stenting.

Reversal of slow flow phenomenon during primary stenting by bail-out administration of abciximab

BACKGROUND: Slow flow or no reflow phenomenon is increasingly being recognized as a serious problem during coronary angioplasty and stenting. This phenomenon is seen more often during angioplasty in highly thrombogenic milieux, especially in a setting of acute myocardial infarction. The treatment of this complication is often not satisfactory. In this study the authors assessed the efficacy of abciximab, a potent antiplatelet drug, in treating slow flow or no reflow phenomenon during primary percutaneous transluminal coronary angioplasty (PTCA) for acute myocardial infarction (AMI). METHODS: Twenty-one instances of persistent slow flow phenomenon were encountered in 131 consecutive patients subjected to primary PTCA for AMI (16%). It was more common in patients presenting with AMI complicated by cardiogenic shock (nine of 21, 43%). Of these 21 cases of slow flow, 10 patients were given injection abciximab during the procedure of primary PTCA as a bail-out measure after encountering the complication of slow flow or no reflow. A pre-discharge coronary angiography was carried out in all patients who survived. RESULTS: In seven of 10 patients in the abciximab group flow had improved to TIMI-3. In contrast, in the non-abciximab group TIMI flow improved in only four of 11 patients. Patients with persistent slow flow had significantly higher mortality at the first 30-day follow-up than patients with TIMI-3 flow (33% versus 1.8%, p<0.001). CONCLUSION: In this small nonrandomized study significant improvement in coronary flow was achieved by using intravenous abciximab after observing slow flow or no reflow phenomenon during primary PTCA. More frequent use of this drug in this milieu might help in preventing the development of this complication. Larger studies are warranted to confirm this life-saving beneficial effect of bail-out administration of abciximab during primary angioplasty.

Elective stenting of extracranial carotid arteries

OBJECTIVES

In symptomatic and asymptomatic patients with significant carotid artery stenosis, surgical endarterectomy has been shown to be beneficial when compared with medical management. Carotid stenting is evolving as an alternative technique for treating such patients. This prospective study was designed to assess the feasibility and safety of carotid angioplasty and stenting.

METHODS

Fourteen patients (15 carotid arteries) with significant carotid artery stenosis were enrolled. These patients were in the age range 46 to 84 years (mean 60.9 +/- 7 years) and there were 12 males (86%). All of these patients were symptomatic with either TIA (n = 8) or stroke (n = 6). Wallstents were used in all the cases to stent the carotid arteries. One patient underwent bilateral carotid artery stenting.

RESULTS

Carotid angioplasty and stenting was successful in 13 out of 14 (92.8%) patients and 14 out of 15 (93.3%) carotid arteries, with reduction in mean (+/- SD) stenosis from 86 +/- 6% to 3 +/- 3%. There was one episode of minor stroke, no major stroke or death during the initial hospitalization. Another patient had a minor stroke with patent ipsilateral carotid artery (on repeat angiography) during the first 30 days after the procedure. This patient was also found to have asymptomatic thrombus formation in the contralateral carotid stent which resolved with intravenous anticoagulation. During a mean follow up of 6 +/- 2 months there has been no recurrence of symptoms.

CONCLUSIONS

Based upon our limited experience we believe that percutaneous carotid angioplasty with stenting is feasible with low periprocedural complication rate.