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Marathon running is presumed to improve cardiovascular risk, but health benefits of high volume running are unknown. High-resolution coronary computed tomography angiography and cardiac risk factor assessment were completed in women with long-term marathon running histories to compare to sedentary women with similar risk factors.Women who had run at least one marathon per year for 10-25 yr underwent coronary computed tomography angiography, 12-lead ECG, blood pressure and heart rate measurement, lipid panel, and a demographic/health risk factor survey. Sedentary matched controls were derived from a contemporaneous clinical study database. CT scans were analyzed for calcified and noncalcified plaque prevalence, volume, stenosis severity, and calcium score.Women marathon runners (n = 26), age 42-82 yr, with combined 1217 marathons (average 47) exhibited significantly lower coronary plaque prevalence and less calcific plaque volume. The marathon runners also had less risk factors (smoking, hypertension, and hyperlipidemia); significantly lower resting heart rate, body weight, body mass index, and triglyceride levels; and higher high-density lipoprotein cholesterol levels compared with controls (n = 28). The five women runners with coronary plaque had run marathons for more years and were on average 12 yr older (65 vs 53) than the runners without plaque.Women marathon runners had minimal coronary artery calcium counts, lower coronary artery plaque prevalence, and less calcified plaque volume compared with sedentary women. Developing coronary artery plaque in long-term women marathon runners appears related to older age and more cardiac risk factors, although the runners with coronary artery plaque had accumulated significantly more years running marathons.

Annuloplasty is the cornerstone of surgical mitral valve repair. A percutaneous transvenous catheter-based approach for mitral valve repair was tested by placing a novel annuloplasty device in the coronary sinus of sheep with acute ischemic mitral regurgitation. Mitral regurgitation was reduced from 3-4+ to 0-1+ in all animals (P < 0.03). The annuloplasty functioned by reducing septal-lateral mitral annular diameter (30 +/- 2.1 mm preinsertion vs. 24 +/- 1.7 mm postinsertion; P < 0.03). These preliminary experiments demonstrate that percutaneous mitral annuloplasty is feasible. Further study is necessary to demonstrate long-term safety and efficacy of this novel approach.

OBJECTIVES The study evaluated a nonsurgical means of intramyocardial cell introduction using the coronary venous system for direct myocardial access and cell delivery. BACKGROUND Direct myocardial cell repopulation has been proposed as a potential method to treat heart failure. METHODS We harvested bone marrow from Yorkshire swine (n = 6; 50 to 60 kg), selected culture-flask adherent cells, labeled them with the gene for green fluorescence protein, expanded them in culture, and resuspended them in a collagen hydrogel. Working through the coronary sinus, a specialized catheter system was easily delivered to the anterior interventricular coronary vein. The composite catheter system (TransAccess) incorporates a phased-array ultrasound tip for guidance and a sheathed, extendable nitinol needle for transvascular myocardial access. A microinfusion (IntraLume) catheter was advanced through the needle, deep into remote myocardium, and the autologous cell-hydrogel suspension was injected into normal heart. Animals were sacrificed at days 0 (n = 2), 14 (n = 1, + 1 control/collagen biogel only), and 28 (n = 2), and the hearts were excised and examined. RESULTS We gained widespread intramyocardial access to the anterior, lateral, septal, apical, and inferior walls from the anterior interventicular coronary vein. No death, cardiac tamponade, ventricular arrhythmia, or other procedural complications occurred. Gross inspection demonstrated no evidence of myocardial perforation, and biogel/black tissue dye was well localized to sites corresponding to fluoroscopic landmarks for delivery. Histologic analysis demonstrated needle and microcatheter tracts and accurate cell-biogel delivery. CONCLUSIONS Percutaneous intramyocardial access is safe and feasible by a transvenous approach through the coronary venous system. The swine offers an opportunity to refine approaches used for cellular cardiomyoplasty.

Exposure of vascular cell-seeded, tubular, biodegradable polymers to pulsatile flow conditions has been proposed as a method to develop tissue-engineered blood vessels by "maturing" structural integrity, and increasing collagen content, suture retention, burst pressure, and tissue formation. These in vitro tissue-engineered arteries demonstrate contractile responses to pharmacologic agents and express markers of vascular differentiation. Current methods to induce pulsatile flow in a bioreactor system are limited by the creation of nonphysiologic pressure waveforms and noncompliant reservoirs to house the tissue-engineered vascular constructs. We have developed a novel method for the in vitro development of tubular vascular structures by using a mechanical ventilator to induce pulsatile, laminar flow into a fluid column, resulting in pressurized waveforms similar to mammalian physiology. The vascular constructs are housed in semicompliant tubing to facilitate an additional variable of circumferential stretch as a potential signaling mechanism. This approach more closely approximates mammalian physiology and we hypothesize that it will facilitate mechanical signaling necessary for the development of tissue-engineered vessels for clinical applications.

Two specific areas in interventional cardiology have, until recently, remained problematic. First is the emerging issue of the so-called 'no option' patient, considered untreatable by conventional percutaneous coronary intervention (PCI) or surgery. Second is the long-standing dilemma of restenosis following PCI. Strategies addressing these two critical areas have been the subject of intense research efforts recently. Several important breakthroughs are being made in the important areas of novel revascularization techniques, antirestenotic agents and stent-based delivery methods. It is conceivable that these novel developments will soon mean that a broader range of patients can be treated, and that the issue of restenosis will now be seriously challenged.

A number of mechanical adjuncts to intracoronary stenting are now available to the interventional cardiologist. These devices have assisted in the development of a safer and more effective stenting practice. Intravascular ultrasound-guided stenting has been shown to reduce the rate of subacute thrombosis and subsequent restenosis. It allows a greater appreciation of lesion structure and severity so that an appropriate intervention strategy can be devised. Debulking techniques may allow the optimal deployment of stents so that restenosis is reduced; however, the results of large randomized studies are still awaited. The use of thrombectomy and distal embolization protection devices is emerging as a safer alternate to stenting alone in difficult patient subsets, such as those with thrombus-laden lesions and degenerated vein grafts. Doppler and pressure wires may be useful in determining optimal stent deployment and predict subsequent patient outcomes. An understanding of the indications and limitations of these devices is of increasing importance to the interventional cardiologist as the coming decade threatens to yield an impressive array of high-tech innovations. Curr Opin Cardiol 2001

Abstract —Diffuse coronary artery disease is frequently untreatable by coronary artery bypass or angioplasty. Many such “no-option” patients have been subjects for trials of angiogenesis using growth factor manipulation or laser injury. We think these novel revascularization strategies are limited by insufficient inflow to putative areas of new microvasculature and thus seek a more mechanical solution. We report the use of a catheter-based system for arterializing the adjacent anterior cardiac vein in a patient with chronic total occlusion of the left anterior descending coronary artery. A composite catheter system (phased-array ultrasound imaging system mounted on a catheter with extendable nitinol needle) was used to deliver an exchange-length intracoronary guidewire from the proximal left anterior descending coronary artery into the parallel anterior interventricular vein. Using standard angioplasty techniques, a fistula was then constructed from the proximal artery to the coronary vein using a self-expanding connector. The proximal vein was blocked with a novel self-expanding “blocker,” thus precluding “steal” through the coronary sinus and forcing retroperfusion of the anterior wall. The procedure was completed without complication, and a follow-up angiogram at 3 months confirmed continued patency of the arteriovenous connection. This patient, who had severe angina before the procedure, has been asymptomatic for 12 months. Percutaneous in situ venous arterialization may be an effective therapy for diffuse, “untreatable” coronary disease by supplying a robust inflow of arterialized blood via retroperfusion to severely ischemic myocardium.

Summary Background Percutaneous transmyocardial laser revascularisation (PTMR) is a proposed catheter-based therapy for refractory angina pectoris when bypass surgery or angioplasty is not possible. We undertook a randomised trial to assess the safety and efficacy of this technique. Methods 221 patients with reversible ischaemia of Canadian Cardiovascular Society angina class III (61%) or IV (39%) and incomplete response to other therapies were recruited from 13 centres. Patients were randomly assigned PTMR with a holmium:YAG laser plus continued medical treatment (n=110) or continued medical treatment only (n=111). The primary endpoint was the exercise tolerance at 12 months. Analyses were by intention to treat. Findings 11 patients died and 19 withdrew; 92 PTMR-group and 99 medical-treatment-group patients completed the study. Exercise tolerance at 12 months had increased by a median of 89·0 s (IQR -15 to 183) with PTMR compared with 12·5 s (−67 to 125) with medical treatment only (p=0·008). On masked assessment, angina class was II or lower in 34·1% of PTMR patients compared with 13·0% of those medically treated. All indices of the Seattle angina questionnaire improved more with PTMR than with medical care only. By 12 months there had been eight deaths in the PTMR group and three in the medical treatment group, with similar survival in the two groups. Interpretation PTMR was associated with increased exercise tolerance time, low morbidity, lower angina scores assessed by masked reviewers, and improved quality of life. Although there is controversy about the mechanism of action, and the contribution of the placebo effect cannot be quantified, this unmasked study suggests that this palliative procedure provides some clinical benefits in the defined population of patients.

Background —Coronary remodeling plays a significant role in lumen loss in transplant allograft vasculopathy (TxCAD), but the determinants of remodeling are unknown. We assessed the relationship between remodeling and plaque topography, coronary compliance, and blood flow in TxCAD. Methods and Results —One artery in each of 27 transplant patients was investigated with simultaneous intravascular ultrasound and coronary flow measurements (basal and hyperemic by Doppler flow wire). At 4 to 8 different cross sections (mean 5.1±1.2), plaque topography (concentric or eccentric) was determined, and total vessel area, lumen area, and intimal/medial area (IMA) were measured. Mean remodeling ratio (vessel area/IMA) in eccentric lesions (E, n=28) was significantly larger than that in concentric lesions (C, n=70) (E 5.87±0.93 versus C 3.58±0.62; P P =NS) and distribution of imaged segments. Remodeling ratio was consistently larger in eccentric lesions in all 3 vessel segments when analyzed separately, and mean remodeling ratio for each artery was larger in vessels with predominantly eccentric lesions. Coronary compliance ([Δ lumen area/diastolic lumen area]/Δ mean arterial pressure×10 3 ) was also significantly greater in eccentric lesions versus concentric lesions (proximal 1.00±0.39 versus 0.22±0.04; mid 0.71±0.17 versus 0.21±0.10; distal 0.43±0.13 versus 0.01±0.08; all P P Conclusions —Vessel remodeling in transplant vasculopathy is significantly greater in eccentric lesions than in concentric lesions, possibly due to greater coronary compliance and resistive vessel function.

Stenting lesions with favorable characteristics as required for inclusion in the STRESS/ BENESTENT trials have yielded superior results to that of PTCA alone. Results for less favorable lesions such as in small vessels, diffuse disease, ostial disease, and saphenous vein grafts are less well established. This review seeks to analyze available data for stent placement in this subset of non-STRESS/BENESTENT lesions.

OBJECTIVESThis study evaluates the feasibility and safety of a catheter-based laser system for percutaneous myocardial revascularization and analyses the first clinical acute and long-term results in patients with end-stage coronary artery disease (CAD) and severe angina pectoris.BACKGROUNDIn patients with CAD and intractable angina who are not candidates for either coronary artery bypass grafting (CABG) or percutaneous transluminal coronary angioplasty (PTCA), transmyocardial laser revascularization (TMR) has been developed as a new treatment that results in reduced angina pectoris and increased exercise capacity. However, surgical thoracotomy is required for TMR with considerable morbidity and mortality.METHODSA catheter-based system has been developed that allows creation of laser channels in the myocardium from within the left ventricular cavity. Laser energy generated by a Holmium: YAG (Cardiogenesis Corporation, Sunnyvale, California) laser was transmitted to the myocardium via a flexible optical fiber capped by an optic lens. The optical fiber was maneuvered to the target area under biplane fluoroscopy through a coaxial catheter system permitting movement in three dimensions.RESULTSThirty-four patients with severe CAD not amenable to either CABG or PTCA and refractory angina pectoris (Canadian Cardiologic Society [CCS] Angina Scale Class III–IV) were included in the study. Ischemic regions were identified by coronary angiography and confirmed by thallium scintigraphy. The percutaneous myocardial revascularization (PMR) procedure was successfully completed in all patients. In 29 patients, one vascular territory of the left ventricle and in 5 patients, two vascular territories were treated. Eight to fifteen channels were created in each ischemic region. Major periprocedural complications were limited to an episode of arterial bleeding requiring surgical repair. There was one death early after PMR, due to a myocardial infarction (MI) in a nontreated region. Clinical follow-up at 6 months (17 patients) demonstrated significant improvement of angina pectoris (CCS class before PMR: 3.0 ± 0.0, six months after PMR: 1.3 ± 0.8, p < 0.0001) and increased exercise capacity (exercise time on standard bicycle ergometry before PMR: 384 ± 141 s, six months after PMR: 514 ± 158 s, p < 0.05), but thallium scintigraphy failed to show improved perfusion of the laser treated regions.CONCLUSIONSPercutaneous myocardial revascularization is a new safe and feasible therapeutic option in patients with CAD and severe angina pectoris not amenable to either CABG or PTCA. Initial results show immediate and significant improvement of symptoms and exercise capacity but evidence of improved myocardial perfusion is still lacking.

A coaxial catheter system for containment of distal embolization is described. Utilizing a novel 0.014" hypotube with a distal elastomeric occlusion balloon, the PercuSurge GuardWire functions as a guidewire while trapping distal embolization resulting from more proximal intervention. The particulate debris is evacuated with a single operator exchange aspiration catheter (Export catheter) prior to deflation of the distal occlusion balloon. This animal study confirmed the feasibility of concept. The system was easily delivered through tortuous coronary anatomy. The GuardWire served as an adequate rail for delivery of dilatation balloons and a multitude of stents. There was no evidence of deep wall damage from low-pressure inflation and apposition of the distal occlusion balloon.

The increasing numbers of patients with refractory angina and coronary disease unamenable to traditional methods of revascularization has led to the emergence of new therapeutic approaches. Current data indicate that laser transmyocardial revascularization (TMR), typically requiring open thoracotomy, may provide these patients with improvements in angina class and myocardial perfusion. Recently, a percutaneous, catheter-based myocardial revascularization procedure has been developed with laser technology that permits the creation of channels from the endocardial surface of the left ventricle. This procedure has been evaluated in a pilot study of 30 patients with Canadian class III–IV angina and coronary artery disease unamenable to traditional methods of revascularization. The results demonstrated that the clinical application of percutaneous myocardial revascularization (PMR) is safe, and preliminary data indicate that the majority of patients experienced significant improvement in anginal symptoms. An ongoing multicenter randomized study is comparing PMR with conventional medical therapy in patients with severe, refractory angina, evidence of reversible ischemia, and contraindications to angioplasty or bypass surgery.

Traditional approaches to improve myocardial perfusion in patients with coronary artery disease previously have applied methods to restore blood flow through the existing coronary vessels. In contrast laser myocardial revascularization techniques rely on the creation of new myocardial channels to produce effects leading to improved perfusion and reduction in angina. Laser transmyocardial revascularization (TMR) is performed via open thoracotomy to access the epicardial surface, is relatively safe, and appears to have a beneficial effect on myocardial perfusion. Percutaneous myocardial revascularization (PMR), however, uses transmission of laser energy along a flexible, fiber-optic catheter, thus permitting creation of laser channels from the endocardial surface of the left ventricle via a femoral artery approach. Tissue responses to lasers are dependent upon the energy used and its means of delivery, thermal, mechanical, or chemical effects of laser channel creation may all impact on the myocardium, although stimulation of angiogenic growth factors, with consequent neovascularization appears to be the principal underlying mechanism responsible for improvement in myocardial perfusion. Patients with severe, chronic angina refractory to drug therapies and in whom standard surgical or angioplasty revascularization approaches are not possible may be candidate for TMR or PMR techniques. Clinical studies of TMR have described reductions in angina class, hospital admissions, and the number of myocardial perfusion defects. PMR studies have reported improvements in angina class, increased exercise duration, and trends toward improvement in radionuclide perfusion defects. Randomized trials are underway and will provide more definitive insights into the future clinical role of laser myocardial revascularization techniques.

This Expert Consensus document updates the initial document published in 1996. ### In summary Topics chosen for coverage by Expert Consensus documents are designated because the evidence base and experience with the technology or clinical practice are not sufficiently well developed to be

Background —The validity of quantitative coronary angiography (QCA) after stent placement has been questioned because the optical density of a metallic stent, added to the density of a contrast-filled lumen, could affect border definition. Methods and Results —We deployed 3.0- and 4.0-mm Palmaz-Schatz, Wiktor, Multilink, NIR, and InStent stents in precision-cast phantoms. Central lumens of 2.0 mm were created. There was no difference between the “true” diameters of any stented lumen by both QCA and quantitative ultrasonic (QCU) measurement poststenting. QCA systematic error (SE) varied from 0.01 for the Wiktor stents to 0.14 mm for the Palmaz-Schatz stents; the random error (RE) was 0.03 to 0.14 mm. QCU SE varied from 0.05 to 0.11 mm, and RE ranged from 0.01 to 0.07 mm. At the next stage, 4.0-mm Wiktor and Palmaz-Schatz stents were deployed into the phantom lumens; 1.5-, 2.0-, 2.5- and 3.0-mm lumens were created inside the stents. QCA and QCU measurements of 1.5- to 2.5-mm residual lumens were overestimated by 0.1 to 0.3 mm. In the 3.0-mm residual lumen within the Wiktor stent, QCA underestimated the luminal size by −0.1 mm. There was no QCA inaccuracy for a 3.0-mm lumen within the Palmaz-Schatz stent. In patients, in 25 stented segments in both the Palmaz-Schatz and Wiktor groups, there was no difference between QCA and QCU diameters. Conclusions —QCU is sufficiently precise for the assessment of the coronary lumen after stenting. QCA can be used as an accurate method of poststent assessment, except when a very mild recurrence within a highly opaque stent is measured. In that instance, QCA may underestimate the luminal diameter.

In January 1997, experts from the United States, Europe, and Japan gathered at Stanford University to review their collective experience with intracoronary and noncoronary stenting and to identify and prioritize issues requiring further clinical investigation. This report summarizes the discussions that took place during this stent summit. Knowledge of stent-tissue interaction from animal and human pathologic specimens was reviewed in the context of evolving stent designs. The relative merits of coil and slotted tubular stent designs were discussed. Stent deployment routines, including self-expansion, balloon expansion, and high-pressure delivery were debated. The potential for covered stents and coated stents was explored. Problems surrounding the routine deployment of stents were identified: small vessel disease, long lesions, bifurcation stenoses, vein graft disease, ostial disease, left main stenoses, and intrastent restenosis. The value of intravascular ultrasound, as an adjunct to stenting, was explored and debated. An algorithm for "provisional stenting" based on ultrasound criteria was developed. Noncoronary stenting of the aorta, iliacs, and carotids were discussed. Clinical applications that may lead to randomized clinical trials were identified.

Despite extraordinary growth in percutaneous transluminal coronary angioplasty (>400,000 cases in United States in 1997) patients are still routinely referred for bypass grafting in large numbers. Why? Second-generation devices (directional coronary atherectomy, high-speed rotational atherectomy [Rotablator], and stents) have expanded the application of percutaneous catheter treatment of coronary disease. Specifically, highly eccentric lesions in large vessels, heavily calcified lesions, and coronary dissections can be effectively treated with these devices. Stents have substantially reduced the incidence of restenosis, but this benefit is largely confined to vessels more than 3 mm in diameter and stenoses less than 20 mm in length. A third generation of coronary devices has evolved in the late 1990s in response to continuing failures of conventional balloon angioplasty, atherectomy, and stenting. The failures of the 1990s were (1) restenosis, including in-stent restenosis, (2) chronic total occlusions, (3) diffuse small-vessel disease, and (4) aged vein graft disease. In response to these challenges novel devices are being developed: (1) for restenosis, intracoronary radiation therapy (brachytherapy); (2) for chronic total occlusions, Prima Laser wire; (3) for diffuse small-vessel disease, percutaneous myocardial laser revascularization; and (4) for aged vein grafts, antiembolization devices. Each of these new catheter technologies will need to be economically and clinically reconciled with the multitude of minimally invasive surgical revascularization techniques that are rapidly evolving.

The Prima laser guidewire system (Spectranectics Corp., Colorado Springs, CO) consists of an 0.018" hypotube containing a bundle of 45-microm optical fibers coupled to a pulsed excimer laser operating at a tip fluence of 60 ml/mm2 and a repetition rate ranging from 25-40 Hz. This laser guidewire was specifically designed to cross total occlusions refractory to passage with conventional wires. The Prima wire was evaluated in a feasibility study at 15 U.S. centers. Following failure to cross a total occlusion with approved guidewires, the Prima wire was utilized in 179 patients. Average age of subjects was 61 yr. Lesion locations included left anterior descending (36%), right (45%), and circumflex (19%) coronary arteries. Mean angiographic age of total occlusions was 70 wk (range, 2-1,020 wk, median, 14 wk). The use of the Prima wire either solely or in combination with conventional guidewires resulted in successful crossing in 61% of these previously impenetrable occlusions. Failure of the device was commonly related to length of the occlusion and tortuosity along the occluded pathway. Major complications included myocardial infarction in 7 patients (3.9%), tamponade in 3 (1.7%), and death in 2 (1.1%). This "learning phase" pilot study confirmed the feasibility of a laser guidewire in chronic total occlusions that are resistant to passage of conventional guidewires. An extended registry at these investigative sites is planned.

Transmyocardial revascularization (TMR) is a potential therapy for patients with severe angina pectoris and coronary anatomy deemed unsuitable for traditional revascularization techniques. Investigations of TMR are reviewed with emphasis on studies relevant to the development of a percutaneous, catheter-based transmyocardial revascularization procedure (PMR). The results of the preliminary animal studies and description of the PMR procedure are discussed. The recently initiated human PMR protocol is summarized and possible future investigative directions are outlined.

The use of thrombolytic therapy has been widely accepted for the treatment of acute myocardial infarction. Despite improving mortality, thrombolytic therapy may be contraindicated in many patients presenting with myocardial infarction and is associated with a small, yet significant risk of hemorrhagic sequelae. This article outlines the rationale behind reperfusion therapy, the use of pharmacological thrombolysis and the role of adjunctive angioplasty. The potential advantages of a therapeutic strategy of primary angioplasty, instead of thrombolysis, are discussed. These include anatomical definition, risk stratification, reduced recurrent ischemia, enhanced coronary perfusion and improved coronary patency. The randomized trials in which primary angioplasty and thrombolytic therapy were compared are reviewed. We conclude that angioplasty results in a reduction of short-term mortality and nonfatal reinfarction and therefore advocate the routine use of coronary angioplasty as a primary reperfusion strategy for acute myocardial infarction. The potential limitations of primary angioplasty in the community hospital setting are discussed. Finally, we examine the roles of adjunctive mechanical (e.g. stents) and pharmacological (e.g. Abciximab) means of further enhancing outcomes after primary angioplasty.

The AVE Micro Stent (AVE Inc., Santa Rosa, CA) is composed of helically welded 3 mm long, zigzag crowns with stent lengths from 6 to 39 mm and diameters from 2.5 to 4.5 mm. Quantitative coronary angiography and histologic analyses of acute and chronic implantation were obtained in 52 stented coronary segments of 18 dogs. Three hearts with 8 stented coronary segments were harvested after 24 hr, 3 hearts with 9 stented segments were harvested after 2 weeks, 6 hearts with 15 stented segments were harvested at 8 weeks, and 6 hearts with 20 stented segments were harvested at 24 weeks post-deployment. There were no procedural complications, deaths, or acute vessel closures. The average lumen diameter of the stented segment was largest at 2 weeks (3.3 +/- 0.3 mm). The smallest average diameters were observed at 8 weeks after the stent deployment (2.7 +/- 0.4, P < 0.05) with an increase again at 24 weeks (2.9 +/- 0.6). The pre-explant percent of stenosis was

Laser transmyocardial revascularization (TMR) creates conduits from the left ventricular cavity into the myocardium and has been forwarded as a potential method of perfusing ischemic myocardium. The procedure typically employs a CO2 laser to produce transmyocardial channels from the epicardial to the endocardial surface via an open thoracotomy. Preliminary studies in animals and human subjects have yielded promising results, and clinical trials evaluating the long-term efficacy of the procedure are in progress. We now report the use of a percutaneous method of TMR using a laser delivered through a novel catheter system. To assess the feasibility of performing percutaneous TMR, studies were performed on 15 adult canine subjects utilizing a holmium:YAG laser. Via a femoral artery approach, novel laser catheters were introduced into the left ventricular cavity under fluoroscopic guidance. Biplane coronary angiography, ventriculography, and transesophageal echocardiography were employed to direct catheters to specific regions and assess the efficacy of creating transmyocardial channels. Multiple channels could be created in the anterior, lateral, inferoposterior, and septal regions as demonstrated by contrast ventriculography with confirmation by subsequent gross and histologic examination. The procedure was tolerated well without any ventricular dysfunction or sustained ventricular arrhythmias. We have demonstrated that laser transmyocardial revascularization via a percutaneous approach is feasible with creation of channels from the endocardial surface of the left ventricle into the myocardium. On gross and histological examination, these channels are similar in appearance to those created by the currently employed open chest, epicardial method of TMR. Cathet. Cardiovasc. Diagn. 40:223–228, 1997. © 1997 Wiley-Liss, Inc.

This study evaluates the short-term changes in coronary artery segments treated with high speed rotational atherectomy (HSRA). Quantitative coronary angiographic (QCA) analysis indices, such as degree of expected ablation, elastic recoil, and segmental spasm, were examined in 133 patients and restudied 24 hours after HSRA. The study was also designed to compare the early results of three different HSRA strategies: stand-alone (SA) HSRA; HSRA with adjunctive high (≥ 4 atm) pressure (HP BA) and low (≥ 2 atm) pressure balloon angioplasty (LP BA). Previous studies have suggested negligible elastic recoil after HSRA as well as demonstrated the possibility of further continuous improvement in vessel patency up to 24 hours postprocedure. From a total of 656 patients treated with HSRA, a cohort of 133 patients with successful HSRA of 167 lesions were restudied angiographically at 24 hours. Serial QCA evaluation of the treatment site was performed. Analysis of the relative gain in minimal luminal diameter (MLD) assessed at 24 hours postprocedure showed that the highest gain group (> 40%) had narrower initial lesions compared to moderate gain (1%–40%), or MLD loss groups (MLD 0.5 ± 0.4 mm vs 1.0 ± 0.3 and 1.5 ± 0.4, respectively, P < 0.01). The initial percent diameter stenosis was also higher in the high gain group (77.1 ± 16.0 vs 61.9 ± 11.8 and 53.0 ± 11.9, P < 0.01). Immediately postprocedure there was a significant increase in MLD and a decrease in percent diameter stenosis. There was no difference in residual lesion characteristics postprocedure. While progressive MLD decrease was observed in the loss group (MLD postprocedure 1.6 ± 0.5 and 1.2 ± 0.6 at 24 hours, P < 0.01), a continuous increase in MLD was noted in the high gain group (MLD postprocedure 1.7 ± 0.5 mm vs at 24 hours 2.0 ± 0.5 mm, P < 0.01). The high gain group was characterized by the most lesion debulking, the most pronounced segmental spasm, and the least elastic recoil. Adjunctive HP BA was associated with the largest size vessels (D ref. in SA HSRA group was 2.6 ± 0.8 mm vs 2.9 ± 0.6 mm in LP BA and 3.0 ± 0.7 mm in HP BA groups, P < 0.01), the lowest elastic recoil (SA HSRA 23.8%± 20.9% vs LP BA 15%± 16.8% and HP BA 5.7%± 14.4%, P < 0.05), and the highest incidence of vessel dissection (SA HSRA 8.1% vs LP BA 14.7% and HP BA 34.0%, P < 0.05). However, these larger vessels underwent the least amount of lesion debulking (SA HSRA 46.4%± 27.2% vs LP BA 38.6%± 24.0% and HP BA 30.5%± 19.5%, P SA HSRA vs. HP BA < 0.001). There are measurable degrees of elastic recoil and local spasm observed after HSRA. HSRA of the most severe lesions yields the highest procedural gain, the lowest elastic recoil and the highest index of lesion ablation. In addition, some late increase in the MLD due to the resolution of spasm is observed at 24 hours postprocedure. SA HSRA is associated with higher degrees of expected lesion ablation. This is comparable to the degree of improvement in MLD, where adjunctive percutaneous transluminal coronary angioplasty is utilized as assessed at 24 hours postprocedure. HSRA with adjunctive HP BA yields immediate results showing the least elastic recoil and spasm at the expense of the highest incidence of dissection and side branch loss.

Background Accelerated coronary artery disease is a major cause of mortality in heart transplant recipients; however, it does not appear to play a major role in the clinical outcome of heart-lung transplant recipients. The purpose of this study was to determine whether the incidence and severity of transplant coronary artery disease as detected by intracoronary ultrasound in heart-lung transplant recipients are less than those encountered in heart transplant recipients. Methods and Results We studied the left anterior descending coronary artery with the use of intracoronary ultrasound imaging in 22 heart-lung transplant recipients at the time of their routine annual coronary angiogram. Twenty-two heart transplant recipients were case matched for number of years after transplant at ultrasound study, recipient age, donor age, and diagnosis of nonischemic cardiomyopathy. Mean intimal area, intimal index, Stanford class, and incidence of at least moderate disease (Stanford class ≥3) were measured and calculated in each group and then compared between the two groups. Mean intimal area (1.6±2.5 versus 3.8±2.8 mm 2 ), mean intimal index (0.07±0.10 versus 0.22±0.14), mean Stanford class (1.7±1.0 versus 2.7±1.2), and incidence of Stanford class ≥3 (14% versus 45%) were significantly lower in the heart-lung transplant recipient group. Conclusions The incidence and severity of transplant coronary artery disease are much less in patients receiving heart-lung transplants than in those receiving heart transplants alone.

Cineradiography, using higher kVp and two or more specified profiles for each outlet strut leg, was used to evaluate Bjork-Shiley convexo-concave (C/C) heart valves with epidemiologically defined > 0.1% per year estimated fracture rates. Among 828 mitral valves, eight radiographs were assessed as definite single leg separations (SLS) and 23 were read as probable SLS. Explantation confirmed SLS in 24 valves; 4 probables were false positives, and 3 patients with probable SLS ratings decided against explantation. Four patients with SLS died, an operative mortality of 14%. Only 23 mitral and 6 aortic valves receiving ratings ranging from apparently normal to suspicious have become available for verification; 1 rated apparently normal was found to have a SLS. Two patients experienced fatal fractures and 1 SLS valve was explanted 3 to 15 months after apparently normal x-ray studies; it cannot be known if a SLS was or was not present at the time of these examinations. As 97% of negatively rated valves remain in situ, the sensitivity of the test is similarly not known. Only 1 SLS has been detected among 136 aortic valves. Uncertainty about test accuracy and SLS progression condition the clinical utility of radiographic SLS detection, particularly with respect to assurance from apparently normal readings. However, radiographic identification of an SLS substantially enhances epidemiologically derived risk categorization as a basis for consideration of prophylactic replacement for the approximately 12,000 valves with a > 0.1% estimated annual fracture risk, currently thought to be implanted in living patients.

One hundred twenty-three patients treated with high-speed rotational atherectomy (HSRA) were restudied 6.9 +/- 1.2 months later. At the follow-up, the number of focal concentric lesions increased from 32.2 percent to 63.0 percent, p0.01, with decrease of type C lesions from 54.8 percent to 30.8 percent, p0.05. Comparison of the degree of the net gain (NG) showed more severe baseline lesions in the high-gain group (NG20 percent) compared with the moderate-gain group (20 percentNG0 percent) and to the loss group (minimal luminal diameter [MLD] 0.8 +/- 0.4 mm vs 1.0 +/ 0.4 mm, p0.05; and 1.2 +/- 0.5 mm; p0.01, respectively). Highest initial gain (36.5 percent +/- 26.2 percent vs 24.5 percent +/- 18.1 percent; p0.015; and 19.0 percent +/- 23.2 percent; p0.001) as well as lowest late loss (1.8 percent +/- 21.7 percent vs 14.0 percent +/-18.4 percent; p0.01 and 28.1 percent +/- 25.0 percent; p0.01) were found in the high NG group. A higher interaction between burr and atheroma resulted in the lowest restenosis rate of 6 percent.

Seven hundred ten high speed rotational atherectomy (HSRA) procedures were performed in a single consecutive series of 656 patients. Stand alone HSRA was performed in 253 patients (35%). HSRA with adjunctive low pressure (⩽2 ATM) balloon angioplasty (LP BA) was performed in 221 patients (31%), and HSRA with adjunctive high pressure (⩾4 ATM) balloon angioplasty (HP BA) was performed in 236 patients (34%). Prognostically unfavorable Type B2 and C lesions dominated the study group (74.7%). Procedural success rate was 96%. Emergency coronary artery bypass surgery was performed in 1.4% of cases, Q wave myocardial infarction occurred in 3.4% and death, related to procedure, was consequent in 0.5% of cases. Incidence of flow limiting dissections was 3.1%, distal spasm was 5.3%, and “no reflow” phenomenon was 1.8%. The recent technique modifications included continuous advancer/guiding catheter infusion of the nitroglycerin-verapamil mixture, limitation of duration of lesion engagement by the burr, stepwise increase in the burr size, decrease of rotational speed, and strict control of rpm drop during lesion ablation. Evolution of the interventional technique involved trends towards decrease of the use of HP BA in conjunction with steady increase in the percentage of SA and LP BA procedures over time. These technique changes resulted in complete absence of “no reflow” in 1994, as well as a generalized decrease in overall coronary vascular reactivity from all burr passes. © 1995 Wiley-Liss, Inc.

The longitudinal distribution and circumferential pattern of coronary intimal proliferation were studied with intravascular ultrasonography in 135 patients after heart transplantation. Eighty-seven (64%) of 135 patients had significant intimal thickening, with most lesions (63%) concentric and free of fibrosis or calcification. Both diffuse and nonuniform longitudinal patterns of intimal thickening were found.

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

Objectives: The present study assesses clinical outcomes in patients from the Potential Angina Class Improvement From Intramyocardial Channels (PACIFIC) trial of percutaneous transmyocardial revascularization (PTMR) who had previously been considered “no-option,” but who subsequently underwent percutaneous coronary intervention (PCI) for continuing symptoms. Background: Patients with advanced symptomatic coronary artery disease who are not candidates for coronary artery bypass grafting (CABG) or PCI comprise an important group, for which no established treatment is currently available. These patients have been described as having “no option,” and are currently targeted for various experimental therapies. One such proposed therapy, PTMR, was recently examined in the PACIFIC trial. A subgroup of patients in this trial subsequently underwent PCI, although to initially qualify for the study they had previously been considered as unsuitable for PCI and as having “no option.” The therapeutic benefit of PCI for patients of this type is unknown. Methods: A retrospective analysis was performed on data obtained from all subjects of the PACIFIC study who underwent PCI within the 12-month follow-up period. Results: Ten subjects originally randomized to PTMR and 11 subjects from the medical treatment group underwent PCI. Most had undergone at least one prior PCI and at least one CABG, and there was a high prevalence of cardiovascular risk factors. Despite excellent immediate procedural success, PCI resulted in only modest, statistically nonsignificant increases in mean exercise duration, small improvements in angina status, and no significant improvements in quality of life. Conclusions: These data suggest that PCI provides only marginal—if any—symptomatic benefit in these patients. (J Interven Cardiol 2004;17:87‐91)

Transmyocardial laser revascularization (TMR or TMLR) is a surgical therapy developed to treat patients with debilitating, medically refractory angina pectoris due to epicardial coronary artery disease that is not amenable to treatment using the traditional methods of percutaneous coronary intervention (PCI) or coronary artery bypass graft surgery (CABG). This technique can also be applied percutaneously [percutaneous myocardial revascularization (PMR) or direct myocardial revascularization (DMR)]. The original hypotheses which motivated development of TMR were that: (i) oxygenated blood could flow directly from the left ventricle and perfuse the myocardium; and (ii) such artificially created channels would remain patent. However, experimental data have refuted both hypotheses. In the face of early reports of marked clinical benefits in terms of relief of anginal symptoms, alternate hypotheses to explain the mechanism have been pursued, including TMR-associated neoangiogenesis and cardiac denervation. Clinically, numerous reports of reduction in frequency and severity of anginal symptoms, improved exercise tolerance and improved quality of life have appeared from nonblind registry-type studies as well as nonblind randomized clinical trials of TMR or PMR versus continued medical therapy. TMR was not associated with a significant improvement in survival compared with medical therapy alone in randomized trials. For example, the prospective, randomized Angina Treatments-Lasers and Normal Therapies in Comparison (ATLANTIC) trial found a 1-year mortality of 5% in 92 TMR-treated patients and 10% in 90 patients treated with medication only. No proof of improved myocardial blood flow in hearts of treated patients is currently available. The first randomized study of PMR was the Potential Angina Class Improvement From Intramyocardial Channels (PACIFIC) trial which found significantly greater improvements in anginal symptoms and exercise tolerance with PMR plus medical therapy, compared with medical therapy alone. The preliminary results of two double-blind studies with PMR/DMR have been presented but have not yet been published in full. Whereas PMR-treated patients did significantly better than sham-treated control groups after 6 months in the Blinded Evaluation of Laser Intervention Electively For angina pectoris (BELIEF) trial, there was no difference after 1 year between DMR-treated patients and those treated with medication only in the DMR In Regeneration of Endomyocardial Channels Trial (DIRECT). Different devices used for revascularization in these two trials may explain the disparity in the results, and therefore the efficacy and tolerability of each device should be judged upon data collected with that particular device.

Drug-eluting stents are revolutionizing interventional cardiology. Sirolimus-eluting stents are in widespread clinical use, associated with well-documented remarkably low restenosis rates, and a number of other agents appear promising in clinical trials. These human studies have been preceded by numerous animal studies, foremost among them the pig coronary model of in-stent restenosis (ISR). The histologic response to porcine coronary stenting was described over a decade ago. Porcine stenting studies now provide examinations not only of histology, but also mechanisms of action, toxicity, and biocompatibility. This review therefore examines the current status of this porcine coronary model of ISR. Contemporary methods of pig coronary stenting are discussed. The morphometric, cellular, and molecular analyses of the responses to stent injury are then described. Finally, recent pig coronary drug-eluting stent studies are examined, with a discussion of their advantages, limitations, and possible future modifications.

The study evaluated a nonsurgical means of intramyocardial cell introduction using the coronary venous system for direct myocardial access and cell delivery.Direct myocardial cell repopulation has been proposed as a potential method to treat heart failure.We harvested bone marrow from Yorkshire swine (n = 6; 50 to 60 kg), selected culture-flask adherent cells, labeled them with the gene for green fluorescence protein, expanded them in culture, and resuspended them in a collagen hydrogel. Working through the coronary sinus, a specialized catheter system was easily delivered to the anterior interventricular coronary vein. The composite catheter system (TransAccess) incorporates a phased-array ultrasound tip for guidance and a sheathed, extendable nitinol needle for transvascular myocardial access. A microinfusion (IntraLume) catheter was advanced through the needle, deep into remote myocardium, and the autologous cell-hydrogel suspension was injected into normal heart. Animals were sacrificed at days 0 (n = 2), 14 (n = 1, + 1 control/collagen biogel only), and 28 (n = 2), and the hearts were excised and examined.We gained widespread intramyocardial access to the anterior, lateral, septal, apical, and inferior walls from the anterior interventicular coronary vein. No death, cardiac tamponade, ventricular arrhythmia, or other procedural complications occurred. Gross inspection demonstrated no evidence of myocardial perforation, and biogel/black tissue dye was well localized to sites corresponding to fluoroscopic landmarks for delivery. Histologic analysis demonstrated needle and microcatheter tracts and accurate cell-biogel delivery.Percutaneous intramyocardial access is safe and feasible by a transvenous approach through the coronary venous system. The swine offers an opportunity to refine approaches used for cellular cardiomyoplasty.

Optimization of cell seeding and culturing is an important step for the successful tissue engineering of vascular conduits. We evaluated the effectiveness of using a hybridization oven for rotational seeding and culturing of ovine vascular myofibroblasts onto biodegradable polymer scaffolds suitable for replacement of small- and large-diameter blood vessels. Large tubes (12 mm internal diameter and 60 mm length, n = 4) and small tubes (5 mm internal diameter and 20 mm length, n = 4) were made from a combination of polyglycolic acid/poly-4-hydroxybutyrate and coated with collagen solution. Tubes were then placed in culture vessels containing a vascular myofibroblast suspension (10(6) cells/cm(2)) and rotated at 5 rpm in a hybridization oven at 37 degrees C. Light and scanning electron microscopy analyses were performed after 5, 7, and 10 days. Myofibroblasts had formed confluent layers over the outer and inner surfaces of both large and small tubular scaffolds by day 5. Cells had aligned in the direction of flow by day 7. Multiple spindle-shaped cells were observed infiltrating the polymer mesh. Cell density increased between day 5 and day 10. All conduits maintained their tubular shape throughout the experiment. We conclude that dynamic rotational seeding and culturing in a hybridization oven is an easy, effective, and reliable method to deliver and culture vascular myofibroblasts onto tubular polymer scaffolds.

Strategies to treat atherosclerotic coronary artery disease include coronary artery bypass grafting (CABG), in which grafts are used to bypass atherosclerotic vessels and restore blood flow to the ischemic myocardium. The grafts used include healthy arteries or veins harvested from a separate site. Results with arterial grafts have been superior to venous grafts; promoting the practice of total arterial revascularization using only arterial grafts. Suitable arterial grafts, however, are scarce and harvest procedures add to morbidity and cost. Tissue engineering combines the principles of engineering with life sciences for the development of biological substitutes and restore, maintain or improve tissue function. Advances in this field have included the development of tissue-engineered blood vessels, with the potential to serve as arterial grafts, conduits or fistulae. This review describes the history of tissue engineering arteries, the techniques used, and progress to date. The source of cells and the future direction of this field are explored.

Catheter-based coronary bypass has evolved since its origin in 1995. We present a status update of one version of catheter-based bypass, percutaneous in situ coronary venous arterialization (PICVA), its successes and failures, and the many questions and challenges that remain. Initial clinical experience with PICVA demonstrated promising mitigation of angina in no-option patients, but was complicated by a relatively low procedural completion rate and a high incidence of MACE. A great deal was learned in these initial cases. The system of devices is currently undergoing significant modification, and further clinical study is underway.

Major advances in cardiovascular intervention for chronic disease are underway. These innovations lie at the interface of minimally invasive catheter-based technologies and biologic approaches for the management of complex cardiovasculardiseases. This review highlights key areas where such ‘biointerventional’ cardiovascular therapies are envisioned to occur: cardiac cell transplantation, myocardial gene therapy, genetic and photodynamic endovascular interventions, and vascular tissue engineering.

Background Transmyocardial and percutaneous laser revascularization (TMR, PTMR) may reduce angina and increase exercise tolerance in otherwise untreatable angina patients, although the mechanism is unknown and the placebo effect may be significant. One other proposed mechanism is cardiac denervation leading to silent ischemia. Methods Electrocardiograms obtained during symptom-limited exercise (ETT, modified Bruce protocol) at baseline and 12 months were analyzed (blinded core laboratory) from 182 patients randomized to TMR (n = 92) or medical therapy alone (MED TMR , n=90) and 219 patients randomized to PTMR (n = 109) or medical therapy alone (MED PTMR , n=110). Results Exercise duration increased 1 year after TMR or PTMR relative to medically treated patients (6.8 ± 3.4 min vs 8.6 ± 3.5 min for TMR; 7.3 ± 3.1 min vs 9.1 ± 3.6 min for PTMR, P TMR subjects had ST depression >1.0 mm, >80% had angina during exercise, but only 3% had ST changes without chest pain (silent ischemia). This did not change after TMR. In the PTMR group, more subjects exercised to >1.0 mm ST depression (from 17% to 34%, P PTMR , but the proportion with silent ischemia did not change in either group. Conclusion Exercise tolerance improved after TMR and after PTMR. Relative to PTMR, TMR more effectively suppressed pain during exercise and ischemic ST depression. However, neither TMR nor PTMR induced significant silent ischemia. These results suggest that denervation may not be a significant factor contributing to angina relief after these procedures. The contribution of the placebo effect was not determined by these results. (Am Heart J 2002;143:1052-7.)

Over 1 million percutaneous coronary interventions (PCI) and a half million surgical coronary artery bypass grafting procedures (CABG) are performed in the United States annually for treatment of coronary artery disease. With recent advances in anti-restenosis strategies, the number of PCIs is expected to increase dramatically. Still, these therapies treat relatively discrete coronary lesions. However, there is a relatively large number of patients for whom traditional therapies are not optimal, either because there are diffuse coronary artery lesions, because there are chronic total occlusions, or because, in the instance of bypass surgery, creating proximal or distal anastomoses is problematic. We review three strategies in various stages of development aimed at treating patients not optimally served by traditional forms of revascularization: transmyocardial laser revascularization, angiogenic therapies, and direct ventricle-to-coronary artery bypass. Copyright 2002, Elsevier Science (USA). All rights reserved.

In-stent restenosis (ISR) is a novel pathobiologic process, histologically distinct from restenosis after balloon angioplasty and comprised largely of neointima formation. As percutaneous coronary intervention increasingly involves the use of stents, ISR is also becoming correspondingly more frequent. In this review, we examine the available studies of the histology and pathogenesis of ISR, with particular reference to porcine and other animal models. An overview of mechanical treatments is then provided, which includes PTCA, directional coronary atherectomy and high speed rotational atherectomy. Radiation-based therapies are discussed, including a summary of current problems associated with this modality of treatment. Finally, novel strategies for the prevention of ISR are addressed, including novel developments in stents and stent coatings, conventional drugs, nucleic acid-based drugs and gene transfer. Until recently, limited pharmacologic and mechanical treatment options have been available for both treatment and prevention of ISR. However, recent advances in gene modification and gene transfer therapies and, more particularly, in local stent-based drug delivery systems make it conceivable that the incidence of ISR will now be seriously challenged.

The use of coronary stents improves the outcomes of percutaneous coronary intervention (PCI). This has led to a rapid increase in their use. Coronary stenting is not without problems and is complicated by both early ischemic events and late restenosis. The combination of anticoagulation with unfractionated heparin (UFH) and the use of antiplatelet agents including aspirin, thienopyridines, and glycoprotein IIb/IIIa inhibitors has led to a major reduction in early ischemic events after stenting. Low molecular weight heparin (LMWH) and direct thrombin inhibitors have a number of theoretical advantages over UFH. Their role as an adjunct to coronary stenting is still under investigation. Trials of systemic pharmacotherapy aimed at reducing in-stent restenosis have been consistently disappointing. Preliminary results of stents coated with agents that inhibit neointimal proliferation are extremely promising. The results of ongoing phase III trials of these coated stents are eagerly awaited.

Background —Intracoronary γ- and β-radiation have reduced restenosis in animal models. In the clinical setting, the effectiveness of β-emitters has not been studied in a broad spectrum of patients, particularly those receiving stents. Methods and Results —A prospective, randomized, sham-controlled study of intracoronary radiotherapy with the β-emitting 32 P source wire, using a centering catheter and automated source delivery unit, was conducted. A total of 105 patients with de novo (70%) or restenotic (30%) lesions who were treated by stenting (61%) or balloon angioplasty (39%) received 0 (control), 16, 20, or 24 Gy to a depth of 1 mm in the artery wall. Angiography at 6 months showed a target site late loss index of 11±36% in radiotherapy patients versus 55±30% in controls ( P P =0.012) and at target site plus adjacent segments (22% versus 50%; P =0.018). Target lesion revascularization was needed in 5 radiotherapy patients (6%) and 6 controls (24%; P Conclusions —β-radiotherapy with a centered 32 P source is safe and highly effective in inhibiting restenosis at the target site after stent or balloon angioplasty. However, minimizing edge narrowing and late thrombotic events must be accomplished to maximize the clinical benefit of this modality.

Background —Intravascular ultrasound (IVUS) can assess stent geometry more accurately than angiography. Several studies have demonstrated that the degree of stent expansion as measured by IVUS directly correlated to clinical outcome. However, it is unclear if routine ultrasound guidance of stent implantation improves clinical outcome as compared with angiographic guidance alone. Methods and Results —The CRUISE (Can Routine Ultrasound Influence Stent Expansion) study, a multicenter study IVUS substudy of the Stent Anti-thrombotic Regimen Study, was designed to assess the impact of IVUS on stent deployment in the high-pressure era. Nine centers were prospectively assigned to stent deployment with the use of ultrasound guidance and 7 centers to angiographic guidance alone with documentary (blinded) IVUS at the conclusion of the procedure. A total of 525 patients were enrolled with completed quantitative coronary angiography, quantitative coronary ultrasound, and clinical events adjudicated at 9 months for 499 patients. The IVUS-guided group had a larger minimal lumen diameter (2.9±0.4 versus 2.7±0.5 mm, P 2 , P P Conclusions —These data suggest that ultrasound guidance of stent implantation may result in more effective stent expansion compared with angiographic guidance alone.

Restenosis remains the bane of percutaneous coronary intervention. Local delivery of radiation, brachytherapy, is a promising therapy for the prevention of restenosis. Animal studies have suggested that brachytherapy may be an effective treatment for preventing restenosis. The type of radiation as well as the doses and delivery systems are currently under study; several clinical trials are underway. This paper reviews the biological basis, including animal studies, of intracoronary brachytherapy as well as the current data from clinical trials.

OBJECTIVES This study was designed to evaluate the composition and quantity of particulate debris resulting from vein graft intervention. BACKGROUND Distal embolization and “no reflow” are frequent and important complications resulting from angioplasty of diseased saphenous vein grafts. Little is known about the composition and quantity of embolic particulate debris associated with vein graft intervention, and no intervention has been shown to protect against its clinical consequences. METHODS A catheter system, designed to contain, retrieve and protect against distal embolization of this material, was evaluated during 27 percutaneous interventional saphenous vein graft procedures. Clinical, angiographic and pathologic analyses were performed. RESULTS The duration of distal graft occlusion required to allow intervention and subsequent debris removal was 150 ± 54 s, decreasing as experience was gained. Thrombolysis in Myocardial Infarction trial (TIMI) flow grade increased from 2.6 ± 0.8 to 3.0 ± 0.0. Creatine kinase (CK) rose above normal in three patients (11.1%) exceeding 3× normal in one (3.7%) resulting in the diagnosis of non-Q-myocardial infarction. Particulate material was identified following 21 of 23 procedures suitable for analysis. Particle size was 204 ± 57 μm in the major axis and 83 ± 22 μm in the minor axis. Particles consisted predominantly of soft acellular atheromatous material, such as that typically found under a fibrous cap. Semiquantitative analysis suggested that the quantity of particulate material was less following stenting than following balloon dilation. CONCLUSIONS Particulate matter is commonly present following routine angioplasty and stenting of saphenous vein grafts. Containment, retrieval and analysis of this particulate debris are all feasible. Comparison to prior clinical experience is limited by small sample size. However, to the extent that these particles may contribute to distal embolization, no-reflow and infarction, such a system may contribute to the reduction of complications following vein graft intervention.