Initial experience with a new 8 French-compatible directional atherectomy catheter: Immediate and mid-term results

The purpose of this study was to evaluate the safety and efficacy of the new Fox Hollow atherectomy device (FHT) designed for more efficient and easier plaque removal. The FHT has short rigid section and low-profile cutter mounted on a monorail catheter. The FHT catheter was utilized in 77 patients with 98 lesions. Mean reference vessel diameter was 2.75 +/- 0.51 mm. Successful atherectomy with tissue retrieval was performed in 94 lesions (96%). Following atherectomy, mean diameter stenosis was reduced from 71.1% to 31.9% and further to 10.4% following adjunctive treatment. Angiographic complications were one coronary perforation and one adventitial staining, both successfully treated with prolong balloon inflation and stent implantation. Nine patients (11.7%) had in-hospital non-Q-wave myocardial infarction (MI). One patient died (1.3%) for noncardiac reasons and one had MI (1.3%) at 6-month follow-up. Target lesion revascularization was required in 13 (13.8%) lesions and target vessel revascularization in 15 (20.3%) patients. There was target vessel failure in 17 (23.0%) patients. Plaque debulking with the FHT catheter can be performed safely and effectively in relatively small vessels and complex lesions located in mid-distal artery segments with 6-month clinical outcome similar to prior atherectomy devices.

Insufficient tissue ablation by rotational atherectomy leads to worse long-term results in comparison with balloon angioplasty alone for the treatment of diffuse in-stent restenosis: insights from the intravascular ultrasound substudy of the ARTIST randomized multicenter trial

The ARTIST trial demonstrated a worse outcome for patients with in-stent restenosis (ISR) treated with rotational atherectomy (RA) and adjunctive balloon angioplasty (PTCA) as compared to PTCA alone. This intravascular ultrasound (IVUS) substudy compares effects of lumen enlargement and examines reasons for failure of RA in this setting. IVUS (n = 56) was performed after each interventional step and at follow-up. Volumetric lumen gain measured 79 +/- 68 mm(3) after PTCA (13 +/- 4 atm) as compared to 44 +/- 26 mm(3) after RA and adjunctive PTCA (7 +/- 3 atm; P < 0.0001). RA itself enlarged lumen by only 19 +/- 17 mm(3) and stent volume was 47% smaller as compared to high-pressure PTCA. Low-pressure strategy after RA did not prevent tissue growth during follow-up (19 +/- 25 vs. 36 +/- 38 mm(3); RA vs. PTCA; P = 0.09). Consequently, net lumen gain after PTCA was 82% higher compared to RA (46 +/- 54 vs. 25 +/- 24 mm(3); P = 0.09). Further stent expansion is the key mechanism to achieve luminal gain by PTCA of ISR. Neointimal ablation by RA has only minor effects. Low-pressure PTCA does not prevent recurrent tissue growth and failed for treatment of ISR due to insufficient stent expansion.

Intracoronary radiation to treat in-stent restenosis in six cardiac transplant patients

Transplant vasculopathy significantly limits the survival of cardiac transplant patients and occurs in 50% of patients by 5 years posttransplant. We report our experience with six cardiac transplant patients who underwent intracoronary brachytherapy for in-stent restenosis. At four centers, six patients underwent intracoronary radiation for in-stent restenosis. All patients received extended antiplatelet therapy with clopidogrel and aspirin. Follow-up angiography was performed in all patients. Two of the six patients underwent subsequent target lesion revascularization. Patient 1 presented with total occlusion of her radiated lesion. She had a complex procedure requiring stenting for a dissection after the radiation dwell. Patient 2 had high-grade restenosis following brachytherapy. Patient 3 had a 50% restenotic lesion. Patients 4, 5, and 6 had follow-up angiography that showed no evidence of restenosis. There are few good options to treated accelerated transplant vasculopathy. Radiation therapy may be a viable option in this difficult patient population.

An elevated value of C-reactive protein is the only predictive factor of restenosis after percutaneous coronary intervention

BACKGROUND

The current techniques for percutaneous coronary interventions (PCI) remain limited by restenosis. Recent studies have provided evidence of inflammation playing a role in the pathogenesis of cardiovascular disease.

METHODS

Whether inflammatory markers are predictors of subsequent restenosis were prospectively tested in 272 consecutive patients with angiographically proven coronary artery disease. Patients having undergone PCI at Chonnam National University Hospital, between Sept. 1999 and Mar. 2001, were divided into two groups according to the occurrence of restenosis on a follow-up coronary angiogram: Group I were patients with restenosis (n = 99, 59.5 +/- 10.8 years, M:F = 77:22) and Group II were those without restenosis (n = 173, 58.8 +/- 10.2 years, M:F = 131:42). The IgG seropositivity, cytomegalovirus (CMV) titers, C. pneumoniae. H. pylori and levels of C-reactive protein (CRP) were compared between the two groups.

RESULTS

There were no statistical differences in the seropositivity of the CMV IgG C. pneumoniae IgG and H. pylori IgG between the two groups (Groups I vs. II: 100 vs. 100%, 24.7 vs. 25.7% and 62.2 vs. 63.7%, respectively). Of the angiographic parameters, a low Thrombolysis in Myocardial Infarction (TIMI) flow (TIMI 0 or 1) was more common in Group I than Group II (p = 0.038). The patients with an elevated CRP (> 0.5 mg/dL) were more common in Group I than Group II (57.6 vs. 36.4%, p = 0.001), with the CRP values being higher in Group I than Group II (3.3 +/- 5.8 vs. 1.3 +/- 2.6 mg/dL, p = 0.001). According to a multiple logistic regression analysis, the CRP was the only predictor of restenosis, with an odds ratio of 2.1169 (95% C.I. 1.2062-3.7154, p = 0.009).

CONCLUSION

The CRP value is the most important predictor of restenosis after PCI.

Balloon dilation of native aortic coarctation in infancy

Balloon dilation of aortic coarctation in neonates and infants remains controversial. Between 2/1985 and 8/1999, 80 patients <12 months of age, with native aortic coarctation underwent balloon dilation. The systolic pressure gradient across the stenosed area was reduced significantly acutely from a mean of 45.6+/-19.4 mmHg to 17.9+/-13.8 mmHg. In 55 (68.8%) patients, the procedure was initially successful with a residual gradient of <20 mmHg. In 12.5% of patients, intimal tears were detected after dilation. In 21.3% of patients, obstruction of the femoral artery occurred, which responded to heparin or streptokinase in all. Two patients developed aneuryms immediately after the first intervention. In 1 case, surgery was performed with a successful aneurysmectomy. Severe complications or death in relation to the procedure were not detected. Long-term follow-up was obtained in 66 of 80 (82.5%) patients in a period between 6 to 174 months (median 29 months). In 22/66 (33%) of the infants, within a mean period of 10.9+/-15.2 months after first intervention, a redilation was necessary. Sixteen of 22 were successful procedures. In the remaining six patients, surgery was performed electively. A total of 30/66 who had follow-up (45%) patients remained free from reintervention or surgery after the first procedure. Further analysis of the data according to age showed that neonates and infants < or =3 months of age had a 90% and 62% higher residual stenosis rate, respectively, than infants >3 months. In this young age group, balloon dilation can only be recommended as palliation in young infants with severe left venticular dysfunction or in the case surgery is prohibitive for other reasons.

Multiple ulcerations in plaque behind stent struts resulting in late stent malapposition after gamma brachytherapy for in-stent restenosis

Late stent malapposition is an undesired effect of intracoronary brachytherapy. This case report describes multiple ulcerations in plaque behind stent struts, resulting in multiple late stent malappositions, after intracoronary gamma brachytherapy for in-stent restenosis.

Sonotherapy, antirestenotic therapeutic ultrasound in coronary arteries: the first clinical experience

We studied the safety and feasibility of intracoronary sonotherapy (IST) and its effect on the coronary vessel at 6 months. Thirty-seven patients with stable or unstable angina were included (40 lesions). The indication was de novo lesion (n = 26), restenosis (n = 2), in-stent restenosis (n = 11), and a total occlusion of a venous bypass graft. After successful angioplasty, IST was performed using a 5 Fr catheter with three serial ultrasound transducers operating at 1 MHz. IST was successfully performed in 36 lesions (success rate, 90%). IST exposure time per lesion was 718 +/- 127 sec. During hospital stay, one patient died due to a bleeding complication. At 6-month follow-up, one patient experienced acute myocardial infarction, eight patients underwent repeat PTCA. No patient underwent CABG. Late lumen loss was 1.05 +/- 0.70 mm with a restenosis rate of 25%. IVUS analysis revealed a neointima burden of 25% +/- 11%. IST can be applied safely and with high acute procedural success. Sonotherapy-related major adverse events were not observed. Late lumen loss and neointimal growth were similar to conventional PTCA approaches. These results justify the initiation of randomized clinical efficacy studies.

[Coronary stent implantation in elderly patients: acute and long-term results]

The number of elderly patients with coronary heart disease is rapidly growing. Morbidity, related with PTCA is increased in elderly patients, presumably because of the more complex adverse baseline characteristics. However, it has not been firmly elucidated whether routine use of coronary stents is associated with a more favourable outcome in this population. Therefore, we investigated the influence of age on acute procedural success, rate of restenosis (quantitative coronary angiography) and major cardiovascular events (death/myocardial infarction [MI]) 6 months after intra-coronary stent implantation in 1306 patients. Patients were categorised into < 65 years (n = 709),65-75 years (n = 443) and >75 years (n= 154).

RESULTS

Older patients had a higher amount of multivessel disease (p < 0.001) and a lower left ventricular ejection fraction (p < 0.001). Nevertheless, the rate of acute success and restenosis were comparable between the different age groups. In contrast, older patients had significantly more adverse clinical events during long-term followup. (Death/MI < 65 years 3.0%, 65-75 years 3.9%, > 75 years 7.8%, p = 0.02). However, by multivariate analysis age was no longer an independent predictor of adverse clinical events (p = 0.26), which were predominantly determined by coexisting impaired left ventricular function (p < 0.001).

CONCLUSION

After proper judgement of the clinical situation, coronary stent implantation should be considered in selected elderly patients. Thus, advanced age as a solely factor should not be regarded as a contraindication for coronary stent implantation.

Complex transradial three vessel brachytherapy in a single session

BACKGROUND

We report the case of a patient who underwent transradial brachytherapy in 3 different coronary vessels during a single session. She initially presented with unstable angina 4 months after the index procedure; control angiography showed severe and diffuse in-stent restenosis in the LAD, Cx and Mg arteries.

METHODS

After successful dilatation of the three vessels, we performed vascular brachytherapy using the Novoste Beta-Rail system and a 60 mm length source train of 90Sr/Y radioactive seeds. No further stent was implanted. The patient left the hospital the next day. Follow-up angiography revealed widely patent vessels with no restenosis.

CONCLUSION

Transradial multivessel brachytherapy can be done during the same session.

Effect of endothelial shear stress on the progression of coronary artery disease, vascular remodeling, and in-stent restenosis in humans: in vivo 6-month follow-up study

BACKGROUND

Native atherosclerosis and in-stent restenosis are focal and evolve independently. The endothelium controls local arterial responses by transduction of shear stress. Characterization of endothelial shear stress (ESS) may allow for prediction of progression of atherosclerosis and in-stent restenosis.

METHODS AND RESULTS

By using intracoronary ultrasound, biplane coronary angiography, and measurement of coronary blood flow, we represented the artery in accurate 3D space and determined detailed characteristics of ESS and arterial wall/plaque morphology. Patients who underwent stent implantation and who had another artery with luminal obstruction <50% underwent intravascular profiling initially and after 6-month follow-up. Twelve arteries in 8 patients were studied: 6 native and 6 stented arteries. In native arteries, regions of abnormally low baseline ESS exhibited a significant increase in plaque thickness and enlargement of the outer vessel wall, such that lumen radius remained unchanged (outward remodeling). Regions of physiological ESS showed little change. Regions with increased ESS exhibited outward remodeling with normalization of ESS. In stented arteries, there was an increase in intima-medial thickness, a decrease in lumen radius, and an increase in ESS at all levels of baseline ESS.

CONCLUSIONS

The present study represents the first experience in humans relating ESS to subsequent outcomes in native and stented arteries. Regions of low ESS develop progressive atherosclerosis and outward remodeling, areas of physiological ESS remain quiescent, and areas of increased ESS exhibit outward remodeling. ESS may have a limited role in in-stent restenosis. This technology can predict areas of minor plaque likely to exhibit progression of atherosclerosis.

Clinical, angiographic, and interventional follow-up of patients with aortic-saphenous vein graft connectors

BACKGROUND

The use of aortic connectors for proximal saphenous vein bypass graft anastomoses eliminates the need for aortic clamping during coronary artery bypass grafting (CABG) and may reduce the incidence of stroke in the elderly and in patients with severe aortic atherosclerosis.

METHODS AND RESULTS

We studied 74 consecutive patients who received the Symmetry Bypass System aortic connector at the time of CABG. A total of 131 of 144 proximal vein graft anastomoses were performed with this device. The left internal mammary artery was used in 62 patients, and 61 patients had "off-pump" coronary revascularization. A total of 11 patients were readmitted with chest pain consistent with unstable angina 173+/-39 days after CABG. Five of the 11 patients had previous in-stent restenosis before CABG. At angiography, 20 saphenous vein bypass grafts containing 19 connectors were found to have severe stenosis (n=12) or occlusion (n=6) and were treated with angioplasty and stenting or medical therapy. Seven of 11 patients were readmitted 76+/-11 days later with recurrent chest pain and were found to have severe stenosis at the previously stented connector site. Six patients underwent angioplasty followed by brachytherapy. Three of these patients redeveloped chest pain and were readmitted 151+/-71 days later. Two patients were started on oral Rapamune, and one patient underwent redo-CABG.

CONCLUSIONS

Eleven of 74 patients who received aortic connectors at the time of CABG developed symptomatically significant stenosis or occlusion at the connector site shortly after CABG, requiring multiple repeat interventions, including brachytherapy.

Coronary restenosis after sirolimus-eluting stent implantation: morphological description and mechanistic analysis from a consecutive series of cases

BACKGROUND

We describe the clinical and morphological patterns of restenosis after sirolimus-eluting stent (SES) implantation.

METHODS AND RESULTS

From 121 patients with coronary angiography obtained >30 days after SES implantation, restenosis (diameter stenosis >50%) was identified in 19 patients and 20 lesions (located at the proximal 5-mm segment in 30% or within the stent in 70%). Residual dissection after the procedure or balloon trauma outside the stent was identified in 83% of the proximal edge lesions. Lesions within the stent were focal, and stent discontinuity was identified in some lesions evaluated by intravascular ultrasound.

CONCLUSIONS

Sirolimus-eluting stent edge restenosis is frequently associated with local trauma outside the stent. In-stent restenosis occurs as a localized lesion, commonly associated with a discontinuity in stent coverage. Local conditions instead of intrinsic drug-resistance to sirolimus are likely to play a major role in post-SES restenosis.

Long-term outcome of patients with silent versus symptomatic ischemia six months after percutaneous coronary intervention and stenting

OBJECTIVES

We sought to evaluate the incidence of silent ischemia versus symptomatic ischemia six months after percutaneous coronary intervention (PCI) and its impact on prognosis and to test the utility of myocardial perfusion single-photon emission computed tomography (SPECT), or MPS, for risk stratification in these patients.

BACKGROUND

Silent ischemia is frequent after PCI. However, little is known about silent ischemia and long-term outcome after PCI and stenting.

METHODS

In 356 consecutive patients with successful PCI and stenting and follow-up MPS after six months, long-term follow-up (4.1 +/- 0.3 years) was performed. The MPS images were interpreted by defining summed stress, rest, and difference scores (summed difference score [SDS] = extent of ischemia) and related to symptoms and outcome. Critical events included cardiac death, myocardial infarction, and target vessel revascularization.

RESULTS

Eighty-one patients (23%) had evidence of target vessel ischemia, which was silent in 62%. The only independent predictor of silent ischemia was SDS (odds ratio 0.64, p = 0.001). During follow-up, 67 critical events occurred. For patients with an SDS of 0, 1-4, and >4, the critical event rates were 17%, 29%, and 69%, respectively. Similarly, patients without ischemia, silent ischemia, and symptomatic ischemia had 17%, 32%, and 52% of critical events, respectively. Diabetes (relative risk 1.98, p = 0.03) and SDS (relative risk 1.2, p < 0.001) were independent predictors of critical events. The MPS image added incremental information for the prediction of critical events.

CONCLUSIONS

Six months after PCI and stenting, 23% of patients had target vessel ischemia, which was silent in 62%. Silent ischemia predicted a worse outcome than did no ischemia and tended to have a better outcome than symptomatic ischemia. This was closely related to the extent of ischemia. The SDS added incremental value to pre-scan findings with respect to diagnosis and prognosis, indicating the utility of MPS for risk stratification after PCI and stenting.

[Acute coronary syndrome is a common clinical manifestation of in-stent restenosis]

OBJECTIVE

To study the common clinical manifestations of in-stent restenosis.

METHODS

Of 431 patients who underwent percutaneous coronary intervention and repeat catheterization between January 1, 1996 and December 31, 2002, 236 consecutive patients with recurrent ischemia and restenosis were identified: 188 patients with (group I) and 48 without (group II) stenting. Patients who developed early acute stent thrombosis were excluded from the study. In the study we compared the clinical manifestations of in-stent restenosis with those of restenosis without stenting.

RESULTS

Recurrent clinical ischemia occurred at a mean of 5.3 months in group I and 6.1 months in group II (P > 0.05). Rest angina (Braunwald class 2 and 3, 43% vs 27%, P < 0.05), the combination of rest angina and acute myocardial infarction (43% vs 27%, P < 0.05), and angiographically visible thrombosis (7% vs 0%, P < 0.05) were more frequent in group I than in group II.

CONCLUSION

Acute coronary syndromes are the common clinical manifestations of restenosis in patients undergoing percutaneous coronary intervention and occur more frequently in patients with in-stent stenosis than in those with restenosis without stenting.

Resistance to thienopyridines: clinical detection of coronary stent thrombosis by monitoring of vasodilator-stimulated phosphoprotein phosphorylation

We carried out a prospective evaluation of a new vasodilator-stimulated phosphoprotein (VASP) phosphorylation assay in order to detect patients with high-risk coronary subacute stent thrombosis (SAT) despite thienopyridine regimen. Twenty healthy donors (group 1) without any medication were compared to 16 stented patients (group 2) treated by ticlopidin or clopidogrel initiated 2 days before stenting and aspirin (250 mg/day). No difference in platelet reactivity was noted between group 1 and group 2 treated only with aspirin (72.00% +/- 4.17% vs. 69.73% +/- 5.62%, respectively; P = NS). Significant differences were found between patients of group 2 treated with aspirin alone (69.73% +/- 5.62%), after 2.0 days (60.14% +/- 9.60%; P < 0.05), and after 4.8 +/- 1.3 days (48.37% +/- 11.19%; P < 0.05) with thienopyridine-aspirin. Among 1,684 consecutive stented patients, 16 patients who presented an SAT (group 3) were compared with 30 other stented patients free of SAT (group 4). We found a significant difference between group 3 (63.28% +/- 9.56%) and group 4 (39.80% +/- 10.9%; P < 0.0001). VASP phosphorylation analysis may be useful for the detection of coronary SAT.

Percutaneous interventions in radial artery grafts: clinical and angiographic outcomes

In the modern era, radial artery graft is being used with increasing frequency to replace saphenous vein as a conduit for coronary artery bypass surgery. Several reports have shown encouraging early results of radial grafts compared to saphenous grafts. Despite these advantages, radial artery graft failure requiring revascularization does occur. We report on the clinical, angiographic, and technical characteristics and the follow-up results of 22 patients who underwent percutaneous intervention of radial grafts.

Functional testing after coronary artery bypass graft surgery: a meta-analysis

BACKGROUND

A number of studies have examined the diagnostic abilities of various functional tests to assess graft stenosis or the progression of coronary artery disease after coronary artery bypass graft (CABG) surgery. However, a meta-analysis of these studies has not been performed.

OBJECTIVES

To pool the results of studies examining the diagnostic abilities of exercise treadmill testing (ETT), stress myocardial perfusion imaging and stress echocardiography to predict graft stenosis or progression of disease in the native circulation post-CABG.

METHODS

A MEDLINE search was conducted to identify studies examining post-CABG functional testing for the diagnosis of graft stenosis or progression of native disease. Sensitivities and specificities of these studies were pooled, and predictive values and likelihood ratios were calculated.

RESULTS

A pooled analysis demonstrates that for the identification of graft stenosis or progression of native disease, ETT alone has a sensitivity of 45% (95% CI 36% to 54%) and a specificity of 82% (95% CI 68% to 95%). The use of stress myocardial perfusion imaging increased the sensitivity to 68% (95% CI 51% to 86%) and specificity to 84% (95% CI 78% to 91%). The use of stress echocardiography also resulted in an increased sensitivity of 86% (95% CI 78% to 94%) and specificity of 90% (95% CI 84% to 95%).

CONCLUSION

If post-CABG functional testing is performed, stress ventricular imaging is superior to ETT alone for the diagnosis of graft stenosis or progression of disease in the native vessels.

Vessel caliber and restenosis: a prospective clinical and angiographic study of NIR stent deployment in small and large coronary arteries in the same patient

Retrospective analyses of patient cohorts undergoing stent deployment have shown that small vessel diameter and long lesion length are two angiographic predictors of increased restenosis. We determined the effects of these factors in patients with lesions treated in both small- and large-diameter coronary arteries. This multicenter prospective quantitative angiographic study evaluated patients with de novo coronary disease undergoing intervention who had at least two lesions < or = 16 mm length, one in a vessel < or = 2.75 mm diameter (9 or 16 mm length seven-cell NIR stent) and the other in a vessel > or = 3.0 mm diameter (9 or 16 mm nine-cell NIR stent). Of 94 patients enrolled, 76% were male, mean age was 62 years (range, 40-85), 41% were hypertensive, 18% had diabetes, 15% were current smokers, and 64% had hypercholesterolemia. Additional lesions were treated in 23% of patients. The procedural success rate was 99%. Six months postprocedure, there were no deaths or late stent occlusions. One patient suffered a Q-wave myocardial infarction, one a non-Q-wave infarction, eight underwent percutaneous reintervention, two coronary artery bypass graft surgery operations, and five stenting of other nonstudy lesions. The mean reference diameter for the small vessel was 2.35 mm and the large vessel 3.22 mm. Six-month angiography was performed in 87 patients (92% of those eligible). The overall restenosis rate was 24% in the small vessel (9 mm length stent, 17%; 16 mm length stent, 30%) and 15% in the large vessel (9 mm length stent, 3%; 16 mm length stent, 22%), respectively. Multivessel stenting including treatment of lesions in small-caliber vessels can be performed with a good clinical and angiographic outcome. When the patient, operator, technique, and stent type are the same, vessel caliber and stent length both appear to influence the restenosis rate.

Recanalization of chronic and long occlusive in-stent restenosis using optical coherence reflectometry-guided radiofrequency ablation guidewire

Chronic total occlusions remain a challenge to interventionalists due to failure of crossing or perforation by strong wires. We describe the use of a system using optical coherence reflectometry for navigation and radiofrequency ablation to enable wire passage through occlusions that could not be crossed by conventional guidewires.

[Drug-eluting stents in complex lesions]

Interventional cardiology has evolved tremendously over the past two years with the advent of drug-eluting stents. The RAVEL trial was the first randomized study conducted with sirolimus-eluting stents in a selected population of patients in whom a 0% rate of binary restenosis was achieved. The objective of the SIRIUS trial conducted in a more complex patient population was to test the efficacy of the sirolimus-eluting stent in high-risk settings such as coronary bifurcation lesions.

[In-stent restenosis: which indications for drug-eluting stent?]

In-stent restenosis remains a limitation of stent implantation. Currently, at the exception of brachytherapy, any percutaneous technique is associated with a high recurrent restenosis rate (> 50%) in diffuse in-stent restenosis. Although based on a small number of patients, eluting stents (sirolimus, paclitaxel) appear promising for the treatment of instent restenosis.

Noninvasive determination of coronary blood flow velocity with cardiovascular magnetic resonance in patients after stent deployment

BACKGROUND

In patients with coronary artery stents, no direct noninvasive coronary artery imaging is possible with magnetic resonance (MR). A well-established method for the assessment of the functional significance of a coronary lesion is the measurement of coronary flow reserve by invasive intracoronary Doppler. The purpose of the study was to determine coronary flow velocity reserve (CFVR) with MR after stent deployment.

METHODS AND RESULTS

Thirty-eight patients after successful PTCA and stent deployment were included. CFVR was measured perpendicular to the artery distal to the stent using phase-contrast velocity quantification at rest and during adenosine-stimulated hyperemia with a 1.5T MR tomograph (ACS NT, Philips). Measurements were repeated after 3 months and compared with invasive coronary angiography. In 18 patients, additional invasive Doppler flow measurements were obtained. CFVR could be determined in 29 of 38 (76%) of the patients. After 3 months, significant differences were obtained between coronary arteries with and without restenosis. Using a threshold of 1.2, a sensitivity of 83% with a specificity of 94% was achieved for > or =75% stenoses. CFVR with CMR was similar to Doppler results (r=0.87), with a mean relative difference of 7.5%.

CONCLUSIONS

In patients with preserved coronary microcirculating vasoreactivity that are suitable for MR coronary angiography and flow assessments, CMR measures of coronary blood flow velocities reserve may be used to detect in-stent restenosis.

Intracoronary radiation therapy improves the clinical and angiographic outcomes of diffuse in-stent restenotic lesions: results of the Washington Radiation for In-Stent Restenosis Trial for Long Lesions (Long WRIST) Studies

BACKGROUND

The Washington Radiation for In-Stent Restenosis Trial for long lesions (Long WRIST) was designed to determine the safety and efficacy of vascular brachytherapy for the treatment of diffuse in-stent restenosis.

METHODS AND RESULTS

A total of 120 patients with diffuse in-stent restenosis in native coronary arteries (lesion length, 36 to 80 mm) were randomized for either radiation with 192Ir with 15 Gy at 2 mm from the source axis or placebo. After enrollment, 120 additional patients with the same inclusion criteria were treated with 192Ir with 18 Gy and included in the Long WRIST High Dose registry. Antiplatelet therapy was initially prescribed for 1 month and was extended to 6 months in the last 60 patients of the Long WRIST High Dose registry. At 6 months, the binary angiographic restenosis rate was 73%, 45%, and 38% in the placebo, 15 Gy, and 18 Gy radiated groups, respectively (P<0.05). At 1 year, the primary clinical end point of major cardiac events was 63% in the placebo group and 42% in the radiated group with 15 Gy (P<0.05). The major cardiac event rate was further reduced with 18 Gy (22%; P<0.05 versus 15 Gy). Late thrombosis was 12%, 15%, and 9% in the placebo group, 15 Gy group with 1 month of antiplatelet therapy, and 18 Gy group with 6 months of antiplatelet therapy, respectively.

CONCLUSIONS

Vascular brachytherapy with 192Ir is safe and reduces the rate of recurrent restenosis in diffuse in-stent restenosis. The efficacy of vascular brachytherapy on angiographic and clinical outcomes is enhanced with a radiation dose of 18 Gy and prolonged antiplatelet therapy.

Pilot trial of oral rapamycin for recalcitrant restenosis

BACKGROUND

Sirolimus-coated stents are a promising new therapy for restenosis. We treated a select group of patients at especially high risk for restenosis with oral sirolimus.

METHODS AND RESULTS

Patients were treated with an oral sirolimus-loading dose of 6 mg after coronary angioplasty, followed by 2 mg/d for 4 weeks. Serum electrolytes, lipid profile, renal panel, and complete blood cell count were measured at 1, 3, and 5 weeks after drug initiation. Oral sirolimus was prescribed to 22 patients who had a total of 28 lesions and were at high risk for restenosis. Of the 22 study patients, 11 (50%) discontinued oral sirolimus early because of side effects or laboratory abnormalities. Hypertriglyceridemia and leukopenia were the most frequent adverse events, occurring in 3 patients each. All adverse drug effects were reversible after discontinuation. Follow-up was obtained in 100% of patients at a mean of 9.9+/-1.8 months, ranging from 6.5 to 11.8 months. Target lesion revascularization (TLR) occurred in 15 of 28 lesions (53.6%) and 13 of 22 patients (59.1%). There was no difference in TLR for patients receiving a complete course of sirolimus (n=8; 72.7%) compared with patients who terminated treatment prematurely (n=5; 45.5%; P=NS). Clinically driven repeat cardiac catheterization was obtained in 15 (68.2%) patients; restenosis (>50% diameter stenosis at follow-up) was present in 13 (86.7%).

CONCLUSIONS

Oral sirolimus does not appear to provide benefit to patients with recalcitrant restenosis. Adverse drug effects are frequent, underscoring the importance of local drug delivery to achieve high tissue concentrations without systemic adverse drug effects.

The predictive value of exercise QRS duration changes for post-PTCA coronary events

BACKGROUND

The sensitivity and predictive values of exercise ECG testing using ST-T criteria after percutaneous transluminal coronary angioplasty (PTCA) are low, precluding its routine use for screening for restenosis. The predictive value of QRS duration criteria during exercise testing (ET) ECG after PTCA for future coronary events has not been reported. The aim of the study was to compare QRS duration changes with ST-T criteria during ET, as a predictor of coronary events after PTCA.

METHODS

A prospective study of 206 consecutive patients who underwent ET at a mean of 34 +/- 14 days after their first PTCA, and were the followed for a mean of 23 +/- 9 months. Patients were divided by QRS duration into two groups-Q1: ischemic response (QRS duration prolongation of more than 3 ms relative to the resting duration), and Q2: normal response (QRS duration shortening or without change from resting duration). Patients were also divided by their ST-T response, S1: ischemic response, and S2: normal response.

RESULTS

During follow-up 52 patients (58%) experienced restenosis or MI, or underwent CABG-Q1: 44 (85%), Q2: 8(15%) (P < 0.0002), S1: 8 (15%), S2: 44 (85%), (P < 0.641), two patients died-Q1: 1 (1%) and Q2: 1 (1%). For QRS and ST-T, the relative risk of having at least one of the coronary events was 4.02 (CI 2.1-9.9) versus 1.13 (CI 0.8-2.9), respectively. The sensitivity for future coronary events was 85% and 52% and the specificity was 48% and 98% for the QRS and ST-T criteria, respectively.

CONCLUSION

QRS prolongation during peak ET ECG after PTCA is a more sensitive marker than ST-T criteria for detection of patients at risk for later coronary events.

A telemetric measurement system for flow diagnostic after bypass surgery

In medical applications minimal invasive techniques become more and more important. This paper is focused on the results of vascular flow measurements based on micromachined acceleration sensors. A telemetry circuit will be designed to transmit energy to the system and transmit data from it. The sensors were placed outside on artificial blood vessels. With special prepared measuring equipment we have varied the flow through elastic flexible tubes. The tubes were narrowed to different levels to simulate different states of a stenosis. The duty cycled output signals of the acceleration sensors modulates the amplitude of an analogue carrier frequency. The demodulator in the receiving module rebuilds the transferred sensor signals which are evaluated by a microcontroller.

Exercise stress testing, myocardial perfusion imaging and stress echocardiography for detecting restenosis after successful percutaneous transluminal coronary angioplasty: a review of performance

When chest symptoms recur in a patient who underwent percutaneous transluminal coronary angioplasty (PTCA), it is necessary to rule out restenosis (R). Three main noninvasive tests suggest the presence of R: exercise stress test (XT), myocardial perfusion imaging (MPI) and stress echocardiography (s-echo). The objectives of this review were: (1) to estimate the pretest probability of R as a function of time after PTCA in symptomatic patients and (2) to obtain an approximation of the diagnostic parameters of the XT, MPI and s-echo for detecting R. A MEDLINE search (English-language, years: 1980-2001) was conducted to identify studies examining post-PTCA functional testing for diagnosing R. Data from the studies were pooled. Comparing studies was often difficult due to varying methodology in the studies. Pretest probability of R in symptomatic patients increases in a nonlinear fashion from 20% or less at 1 month, to nearly 90% at 1-year postangioplasty. The approximated accuracy of the XT, MPI, and s-echo for detecting R was 62, 82 and 84%, respectively. During the first month after PTCA, none of the noninvasive modalities is able to accurately detect R. Late (7-9 months) after PTCA, the pretest probability of R is high and therefore the noninvasive measure may be spared. Our analysis suggests that MPI and s-echo should be preferred over the XT for diagnosing R.

Preliminary experience with a novel intraoperative fluorescence imaging technique to evaluate the patency of bypass grafts in total arterial revascularization

BACKGROUND

Early graft failure is a common cause of cardiac morbidity and mortality after coronary artery bypass grafting (CABG), and there is particular concern about graft patency in off-pump CABG. We describe our preliminary experience with a novel imaging technique (the SPY system), based on fluorescence of Indocyanine Green when exposed to near infrared light, for the intraoperative assessment of coronary graft patency.

METHODS

Graft patency was assessed in patients undergoing off-pump and on-pump total arterial revascularization. The imaging technique requires injection of a 1-mL bolus of Indocyanine Green into the central venous line, followed by imaging with the SPY system.

RESULTS

We assessed intraoperative graft patency in 213 conduits in 84 patients (mean, 2.54 grafts per patient), of which, 65 (77%) were done off-pump. It took approximately 3 minutes to image each graft. Skeletonized conduits provided better visualization than pedicled ones. Fluorescence, confirming graft patency, was observed in all but four (1.9%) conduits in 4 (5%) patients. In these latter cases, graft revision was necessitated.

CONCLUSIONS

Fluorescence imaging of coronary grafts using the SPY is a uniquely simple, safe, noninvasive, and reproducible technique for intraoperative confirmation of graft patency. In 4 patients, it necessitated revision of the initial intraoperative procedure. Quantification of graft flow would enhance the value of the system.

Intracoronary beta-radiation for the treatment of patients at very high risk for recurrence of in-stent restenosis: a single center experience

BACKGROUND

Intracoronary brachytherapy has significantly reduced the recurrence of in-stent restenosis. The aim of this study was to evaluate the feasibility, safety and efficacy of intracoronary beta-radiation in patients at very high risk for recurrence of in-stent restenosis.

METHODS

We analyzed 42 patients with 50 lesions submitted to catheter-based beta-radiation (Beta-Cath System, Novoste Corporation, Norcross, GA, USA) for in-stent restenosis. Thirty-eight lesions were at the second restenosis, 8 at the third, and 4 at the fourth; a diffuse pattern was present in 78%.

RESULTS

Balloon angioplasty was performed for 30 lesions (60%) and the cutting balloon technique for 20 (40%). In 12 lesions further 14 stents had to be deployed (28%). The delivery catheter was successfully positioned in 96% of the procedures. The mean dwell time was 179 +/- 50 s with a radiation dose ranging from 18.4 to 25.3 Gy, depending on the vessel size. A complete angiographic success without coronary dissection and without any additional stenting after radiation delivery was achieved in 86%. At follow-up (7.2 +/- 2.1 months), the overall restenosis rate was 30.4% (14 lesions). A recurrence was detected in 1/11 lesions with initial focal pattern and in 13/39 lesions with initial diffuse pattern. The restenosis rate was higher in patients in whom a geographic miss had occurred (p < 0.05 vs lesions without geographic miss) and in those in whom a new stent had been deployed (p < 0.05 vs lesions treated without a stent).

CONCLUSIONS

Brachytherapy reduces the in-stent restenosis rate in patients who are at very high risk of recurrence. The restenosis pattern, geographic miss and new stent deployment seem to be negative prognostic factors for recurrence of restenosis.

TAXUS III Trial: in-stent restenosis treated with stent-based delivery of paclitaxel incorporated in a slow-release polymer formulation

BACKGROUND

The first clinical study of paclitaxel-eluting stent for de novo lesions showed promising results. We performed the TAXUS III trial to evaluate the feasibility and safety of paclitaxel-eluting stent for the treatment of in-stent restenosis (ISR).

METHODS AND RESULTS

The TAXUS III trial was a single-arm, 2-center study that enrolled 28 patients with ISR meeting the criteria of lesion length < or =30 mm, 50% to 99% diameter stenosis, and vessel diameter 3.0 to 3.5 mm. They were treated with one or more TAXUS NIRx paclitaxel-eluting stents. Twenty-five patients completed the angiographic follow-up at 6 months, and 17 of these underwent intravascular ultrasound (IVUS) examination. No subacute stent thrombosis occurred up to 12 months, but there was one late chronic total occlusion, and additional 3 patients showed angiographic restenosis. The mean late loss was 0.54 mm, with neointimal hyperplasia volume of 20.3 mm3. The major adverse cardiac event rate was 29% (8 patients; 1 non-Q-wave myocardial infarction, 1 coronary artery bypass grafting, and 6 target lesion revascularization [TLR]). Of the patients with TLR, 1 had restenosis in a bare stent implanted for edge dissection and 2 had restenosis in a gap between 2 paclitaxel-eluting stents. Two patients without angiographic restenosis underwent TLR as a result of the IVUS assessment at follow-up (1 incomplete apposition and 1 insufficient expansion of the stent).

CONCLUSIONS

Paclitaxel-eluting stent implantation is considered safe and potentially efficacious in the treatment of ISR. IVUS guidance to ensure good stent deployment with complete coverage of target lesion may reduce reintervention.

Brachytherapy for refractory coronary artery restenosis

A 76-year-old female patient complained of progressive episodes of chest and left arm pain and numbness, accompanied by a burning sensation in the left breast. The symptoms were nitroglycerine-responsive and consistent with her prior angina. Cardiac history included an initial percutaneous coronary intervention and 4 subsequent occurrences of restenosis in a stented area of the left anterior descending (LAD) coronary artery. Following a fifth restenosis of the LAD, the Novoste Beta-Cath Brachytherapy System was employed following balloon dilatation of the persistent recurrence. At 10 months post-brachytherapy, angiography revealed a patent LAD with no evidence of in-stent restenosis.

Value of coronary stenotic flow velocity acceleration in prediction of angiographic restenosis following balloon angioplasty

INTRODUCTION

Quantitative angiographic assessment after balloon angioplasty is a poor predictor of immediate and long-term outcome. However, the measurement of blood flow velocity during angioplasty has been proved clinically useful.

AIMS

To analyse the value of the maximal stenotic flow velocity and the presence of stenotic flow velocity acceleration (aSV) for the long-term outcome after balloon angioplasty.

METHODS AND RESULTS

Patients undergoing single lesion angioplasty within the DEBATE trial were included. aSV was defined as acceleration in the stenotic coronary flow velocity >50% baseline velocity assessed at a reference site of the target vessel. After balloon angioplasty diameter stenosis, minimal lumen diameter (MLD) and coronary flow velocity reserve were similar between the aSV (n=54) and non-aSV group (n=125). At follow-up, the aSV group had a higher restenosis rate (52% vs 30%, P=0.006) The presence of aSV was the strongest independent predictor of restenosis (OR 3.08, 95% CI 1.35 to 7.05, P=0.008). The best predictive cut-off value of SV was 101cm.s(-1) (sensitivity of 46%, specificity of 81%, positive predictive value of 85% and a negative predictive value of 58%).

CONCLUSION

Following angioplasty, SV appears to be exquisitely sensitive to the changes experienced at the treated area without depending on the status of the microcirculation.

Predicting the risk of restenosis after angioplasty in patients with peripheral arterial disease

Restenosis is a serious therapeutic problem after percutaneous transluminal angioplasty (PTA). Strategies for the prevention of late restenosis include the use of antiaggregatory and anticoagulant drugs, aggressive lipid-lowering, intravascular radiation and others. As some of these therapeutic options are not without side effects it is important to identify patients with an increased risk to develop restenosis. Major clinically recognizable risk factors for restenosis are advanced disease stage and female gender. Elevated plasma levels of fibrinogen, Lp(a), CRP, and migration-inducing activity appear to indicate an unfavorable clinical outcome, and so does post-interventional increase of vWF and PAI-1 antigen. For peripheral arterial disease, only one study has addressed the influence of homocysteine levels upon the restenosis rate after PTA. Although homocysteine levels were elevated in >50% of patients at entry, they were not associated with a higher restenosis rate. Currently the available data allow a rough approximation of a patient's individual risk.

Mechanism of late in-stent restenosis after implantation of a paclitaxel derivate-eluting polymer stent system in humans

BACKGROUND

We recently reported delayed angiographic restenosis in 15 patients who received 7-hexanoyltaxol (QP2)-eluting polymer stents (QuaDS) for the treatment of in-stent restenosis. This study presents the histological findings of atherectomy specimens from a subset of these patients receiving implants.

METHODS AND RESULTS

Between October and December 2001, 5 patients treated with QuaDS-QP2 stents underwent directional coronary atherectomy at 11.2+/-1.0 months for recurrent in-stent restenosis. Restenotic lesion composition was assessed with special stains, immunohistochemistry with quantitative image analysis, and, in one specimen, transmission electron microscopy. Atherectomy specimens contained fibrin interspersed in a smooth muscle cell-rich neointima with proteoglycan matrix. In 2 of 5 specimens, large aggregates of macrophages and T-lymphocytes were noted. These areas of active inflammation demonstrated a relatively high proliferation index by Ki-67 antibody staining, whereas the proliferation index in smooth muscle cell-rich restenotic areas was low.

CONCLUSION

Restenotic lesions from QuaDS-QP2-eluting stents at 12 months show persistent fibrin deposition with varying degrees of inflammation. These pathological changes, representing delayed healing, are usually observed up to only 3 months in human coronary arteries with stainless steel balloon-expandable stents. The nonreabsorbable polymer alone may have induced chronic inflammation.

Inductively coupled stent antennas in MRI

The development of intimal hyperplasia following stent deployment can lead to narrowing or even occlusion of the stent lumen. The underlying mechanisms leading to neointimal proliferation within stents remain largely unknown. Long-term evaluation of stent patency requires a noninvasive means for assessing the stent lumen. MR angiography (MRA) has shown potential to provide noninvasive assessment of the vascular system. However, a detailed assessment of the stent lumen with MRI is often hampered by material-dependent susceptibility artifacts, as well as by radiofrequency (RF) eddy currents generated inside the electrically conducting stent mesh. In this study, stent prototypes were designed to act as active resonant structures at the Larmor frequency of the MR system. Employing the principle of inductive coupling, the B(1) fields of the stents were coupled to that of an outside surface coil. The stents thus acted as local RF signal amplifiers. Various stent designs were investigated regarding their coupling to an external coil, signal homogeneity, and suitability for mechanical expansion for implantation purposes. The dependency of flip angle amplification on the quality factor Q of the stents was systematically investigated. Phantom experiments revealed signal amplification in all stent prototypes. Signal enhancement inside and close to the surface of the stents enabled their localization with high contrast in MR images. In vivo imaging experiments in the iliac, renal, and splenic arteries of two pigs confirmed the in vitro findings. Wireless active visualization of stents allows for detailed analysis of the stent lumen with high contrast and spatial resolution. The proposed method could thus provide a powerful diagnostic means for the noninvasive long-term follow-up of stent patency, thereby enhancing our understanding of the mechanisms of restenosis.

Fate of side branches after coronary arterial sirolimus-eluting stent implantation

The sirolimus-eluting stent (SES) is emerging as a potential solution for the prevention of restenosis. Although the outcome of side branches after stenting with an uncoated metal stent (UMS) has been reported, the fate of side branches after SES implantation is unknown. Furthermore, the absence of spontaneous recanalization of occluded side branches following intracoronary brachytherapy has been previously described and has been related to a delayed healing process. We assessed the procedural and 6-month follow-up angiograms of 238 patients enrolled in the RAVEL study, a double-blind controlled trial of the SES versus the UMS. Any side branch seen on the preprocedure angiogram and subsequently covered by the stent was evaluated. The side branch Thrombolysis In Myocardial Infarction (TIMI) flow grade was assessed at baseline and at follow-up by 2 observers. One hundred twenty-eight patients with > or =1 side branches were identified (63 patients in the SES group with 118 side branches, 65 patients in the UMS group with 124 side branches). Side branch occlusion occurred after stenting in 12 branches (10%) in the SES group and in 9 branches (7%) in the UMS group (p = NS). Of these occluded branches, spontaneous recanalization was observed in 11 branches (92%) in the SES group and in 6 branches (67%) in the UMS group at follow-up angiography (p = NS). Thus, the fate of side branches after SES implantation is favorable and at least as good as after UMS implantation.

Predictive value of preprocedural fibrinogen concerning coronary stenting

Elevated fibrinogen levels after coronary balloon angioplasty have been reported to be useful in predicting restenosis. Therefore, we sought to evaluate the relationship between preprocedural fibrinogen levels and the 6-12-month outcomes of patients undergoing coronary stenting. Plasma levels of fibrinogen were measured in 390 consecutive patients prior to coronary stenting. The primary end point was binary restenosis (percent diameter stenosis of >/=50%). The secondary combined end point was death due to cardiac causes, myocardial infarction related to the target vessel and target lesion revascularization. Patients were grouped into tertiles according to fibrinogen levels. Both at baseline and immediately after procedure, clinical and angiographic characteristics were almost identical in the fibrinogen tertiles. An increase in restenosis rate was observed across the tertiles (18.6, 23.9, 38.1%, P<0.001, respectively). In addition, the frequency of the secondary end point increased in the highest tertile (14.9, 21.5, 37.2%, P<0.001, respectively). Multivariate analysis revealed that high levels of fibrinogen (per 100 mg/dl, OR 1.82, P<0.001) and stent length (P=0.034) were independent predictors for restenosis. An elevated preprocedural fibrinogen level should be considered as a stronger predictor for restenosis after coronary stenting, which might be associated with coagulation and inflammation.

Medium-term follow-up of intermediate coronary stenoses left unrevascularized based on myocardial fractional flow reserve findings

OBJECTIVE

Coronary stenoses of intermediate severity create difficulties in decision making when revascularization is concerned. Myocardial fractional flow reserve (mFFR), an accurate tool to identify physiological significance of individual coronary stenoses, may help solve this problem.

METHODS AND RESULTS

Fifty-eight intermediate (30-70%) coronary stenoses in 51 patients (mean age 54.4 +/- 8.9 years, 9 women) were left unrevascularized because of normal (> or = 0.75) mFFR findings and the patients were prospectively followed with regard to the occurrence of death, myocardial infarction and target vessel revascularization. The mean reference vessel diameter, percent stenosis and mFFR of the intermediate lesions were 3.3 +/- 0.3 mm, 46.8 +/- 9.2% and 0.86 +/- 0.05, respectively. Of the 58 intermediate lesions, 20 (34%) were associated with perfusion defects on thallium scan. Significant (> 70%) disease in addition to the one with the intermediate stenosis was present in I coronary artery in 24 (47%), and 2 coronary arteries in 6 (12%) patients and angioplasty of at least one significant stenosis was performed at the initial evaluation in 18 (35%) patients. Follow-up for a mean of 16.6 +/- 6.6 months disclosed no death or myocardial infarction. Target vessel revascularization was performed in 3 (6%) patients at a mean of 4 +/- 2.6 months. A control angiogram, which was performed in 12 of 18 patients who had undergone angioplasty at the initial evaluation revealed restenosis in 3 (25%) patients with no significant angiographic changes in the target intermediate stenoses. Anginal status was found to be significantly improved at follow-up.

CONCLUSIONS

In this study, we found that intermediate coronary stenoses with an mFFR > or = 0.75 have a favourable medium-term clinical outcome with respect to major cardiac adverse events when left unrevascularized based on mFFR findings.

Debulking and stenting versus debulking only of coronary artery disease in patients treated with cilostazol (final results of ESPRIT)

Stenting inhibits vascular constrictive remodeling after directional coronary atherectomy (DCA). Cilostazol has been reported to control neointimal proliferation after stenting. This study's aim was to examine the effect of debulking and stenting with antirestenotic medication on restenosis. After optimal DCA, 117 lesions were randomly assigned to either the DCA with stent (DCA-stent) (58 lesions) group or the DCA only (59 lesions) group. Multilink stents were implanted in the DCA-stent group. Cilostazol (200 mg/day) without aspirin was administered to both groups for 6 months. Ticlopidine (200 mg/day) was given to the DCA-stent group for 1 month. Serial quantitative angiography and intravascular ultrasound (IVUS) were performed at the time of the procedure and at 6-month follow-up. The primary end point was 6-month angiographic restenosis. Clinical event rates at 1 year were also assessed. Baseline characteristics were similar. All procedures were successful. No adverse effects to cilostazol were observed. Postprocedural lumen diameter was significantly larger (3.27 vs 2.92 mm; p <0.0001) in the DCA-stent group. However, the follow-up lumen diameter was not significantly different (2.53 vs 2.41 mm, DCA-stent vs DCA). IVUS revealed that intimal proliferation was significantly larger in the DCA-stent group (4.2 vs 1.5 mm(2); p <0.0001), which accounted for the similar follow-up lumen area (6.5 vs 7.1 mm(2)). The restenosis rate was low in both groups (5.4% vs 8.9%), and the difference was not significant. Clinical event rates at 1 year were also not significantly different. These results suggest that optimal lesion debulking by DCA does not always need adjunctive stenting if cilostazol is administered.

Developments in restenosis

Restenosis is a major complication leading to the failure of vascular procedures, including surgery, angioplasty and stenting. Major efforts including over 100 clinical trials have been made to overcome this complication, with little success to date. Issues relating to trial rationale, design, measurement and biology are addressed in this review.

Interventional nuclear medicine in the prevention of restenosis following angioplasty

Restenosis is an unsolved clinical and economic limitation of angioplasty. Local irradiation is a new concept to overcome this problem. The magnitude of this health problem becomes apparent when one recognizes that 166132 percutaneous transluminal coronary angioplasty (PTCA) procedures were performed in Germany in 1999. Each angioplasty has subsequent costs of 6384 DM, which can be reduced to 2161 DM by 50% restenosis reduction due to irradiation [1]. The number of diagnostic and therapeutic procedures is growing by at least 10% per year.

Elective stenting in small coronary arteries: results of the Italian prospective multicenter registry MICROSCOPE

BACKGROUND

The role of stent implantation in small coronary arteries is still controversial. The MICROSCOPE study (Ministenting in small coronary arteries, a prospective evaluation) is a multicenter registry addressed to prospectively evaluate the immediate and mid-term clinical and angiographic results of elective stenting of lesions located in coronary arteries with an angiographic reference diameter < or = 2.75 mm.

METHODS

A total of 146 patients (160 lesions) were included in the study. The percentage of complex lesions (B2 and C lesions) was 49.3%. The clinical indications for stent implantation were: stable angina (55.0%), unstable angina (24.6%), and clinical evidence of myocardial ischemia in asymptomatic patients (20.4%); 60% of patients had multivessel disease. Stent deployment could be performed in 96.2% of lesions. The baseline reference diameter was 2.12 +/- 0.36 mm. In all cases the Ministent (Cordis, a J&J Company, Miami, FL, USA), specifically designed for small coronary arteries, was employed. The stent was pre-mounted on low profile balloons available in three different diameters (2.25, 2.50 and 2.75 mm) and three different lengths (11, 15 e 26 mm).

RESULTS

The primary endpoint of successful stent-assisted angioplasty in all study vessels without major adverse cardiac events was achieved in 95.8% of the patients. The minimal lumen diameter increased from 0.64 +/- 0.24 to 2.02 +/- 0.43 mm and the dimensions of the stenosis (expressed as a percentage of the diameter of the coronary vessel) decreased from 68.6 +/- 10.8 to 16.2 +/- 10.7% (< 30% standard deviation in all cases). After the procedure all the patients received double antiplatelet therapy for 4 weeks. Post-procedural complications were limited to 2 patients (1.3%) who had a non-Q wave myocardial infarction at 6 months of follow-up; 13 patients (11%) required target lesion revascularization. No patient died following the procedure. Angiographic control was performed in 44% of lesions. The minimal lumen diameter decreased to 1.12 +/- 0.47 mm and the percent stenosis increased to 45.9 +/- 23.2%. The incidence of binary restenosis (stenosis > or = 50%) was 41%.

CONCLUSIONS

Elective stenting of small coronary arteries with the Ministent can be safely performed and is associated with a low incidence of acute or subacute stent thrombosis. The mid-term results indicate a high rate of angiographic restenosis but a low need of target vessel revascularization. These data suggest that stenting cannot be considered the treatment of choice for unselected lesions located in coronary arteries with a small reference diameter, but represents a safe solution if unsatisfactory results are obtained with balloon angioplasty alone.

A direct comparison of noninvasive coronary angiography by electron beam tomography and navigator-echo-based magnetic resonance imaging for the detection of restenosis following coronary angioplasty

RATIONALE AND OBJECTIVES

To compare electron beam tomography (EBT) with MR imaging (MRI) for detection of restenosis after coronary angioplasty (PTCA).

METHODS

One hundred eighteen patients after PTCA were investigated. By EBT, 50 axial images were acquired (3-mm slice thickness, 120-160 mL radiographic contrast agent). MRI was performed using respiratory-gated sequences (24-48 cross-sections, 2-mm slice thickness, 20 mL Gd-DTPA). EBT and MRI images were evaluated concerning high-grade post-PTCA restenosis (> or = 70%) and validated against coronary angiography.

RESULTS

In EBT, 28 patients and in MRI, 31 patients were not evaluable. In the remaining patients, sensitivity for restenosis detection was 90% in EBT (17/19) and 73% in MRI (11/15; P = 0.370). In EBT, specificity was significantly higher (66% vs. 49%, P = 0.043). Overall accuracy was 71% for EBT and 53% for MRI (P = 0.014).

CONCLUSIONS

For the detection of high-grade restenosis after PTCA, EBT demonstrated significantly higher accuracy than MRI.