Advanced Cardiovascular Systems Research Articles

XIENCE V everolimus-eluting coronary stent system: a novel second generation drug-eluting stent

Drug-eluting stents (DES) have been shown to be safe and significantly reduce clinical events and angiographic restenosis in the percutaneous treatment of coronary artery disease. Currently, three DES have been approved in Europe and Northern America: the sirolimus-eluting stent (SES), the paclitaxel-eluting stent (PES) and the zotarolimus-eluting stent (ZES). Everolimus, an analog of sirolimus, is an immunosuppressive and antiproliferative agent. In three studies, the SPIRIT I, FUTURE I and II, the everolimus-eluting stent has proven to be safe, well-tolerated and has shown very favorable clinical and angiographic results. Compared with earlier-generation DES, the XIENCE V everolimus-eluting coronary stent system (Advanced Cardiovascular Systems Inc., an Abbott Vascular Company, CA, USA) may provide enhanced deliverability, radiopacity with thinner strut filaments and, owing to a durable polymer, sustained drug elution and vascular compatibility.

Tracking Technique of a Micro Guide Wire in Sequential Fluorograms

In this paper, we propose a tracking technique for a micro guide wire in a sequence of fluorograms. A technique in which the region-growing technique was embedded was developed. It gives the center line of a micro guide wire. A sequence of 1,024 x 1,024 x 16 bit fluorograms (111 frames) with a carotid phantom and head phantom was obtained with a CAS-8000V (Toshiba America Medical Systems, Inc., CA, USA) C-arm angiography system and a Hi-Torque Standard micro guide wire (Advanced Cardiovascular Systems, Inc., CA, USA). To evaluate the technique, we manually traced the guide wire in each sequence frame three times, and a "true" single-width micro guide wire was created from them. The number of pixels on the true guide wire and inside the two-pixel tolerance of the center line was counted in each fluorogram, and the percentage of that count based on the number of all pixels on the true guide wire was calculated as true positive (TP). In addition, the number of pixels on the center line and outside the two-pixel tolerance of the true guide wire was counted in each frame as false positive (FP). The tracking technique has a mean TP of 94.8% and a mean FP of 5.1 pixels/frame. Several frames have low TP and high FP, but the technique could continue to track the micro guide wire until the end of the sequence. We therefore concluded that we had developed an accurate automatic tracking technique for micro guide wires in fluoroscopic sequences.

Coronary stenting versus balloon angioplasty in small vessels: A meta-analysis from 11 randomized studies

ObjectivesA meta-analysis of 11 randomized trials was done to compare stenting versus balloon angioplasty (BA) in small coronary vessels. BackgroundRandomized studies on coronary stenting (CS) in small vessels have yielded controversial results. MethodsEleven randomized trials on CS versus BA in small vessels, including angiographic re-evaluation at six months, were analyzed. ResultsThe BeStent (Medtronic Instent, Minneapolis, Minnesota) was used in four studies, the Multi-Link (Guidant, Advanced Cardiovascular Systems Inc., Santa Clara, California) in three trials, and the NIR (Boston Scientific Corp., Boston, Massachusetts), JoStent (Jomed International AB, Helsingborg, Sweden), Tenax (Biotronik, Berlin, Germany), and BioDivysio (Abbott Vascular Devices, Redwood City, California) in the remaining four trials. Overall, 3,541 patients were included (1,672 allocated to BA and 1,869 to stent). The rate of cross-over from balloon to stent in the pooled population was 19%, and unsuccessful stent deployment occurred in 2% of the patients allocated to stent. The pooled rates of restenosis were 25.8% and 34.2% in patients allocated to stent and balloon, respectively (p = 0.003) (risk ratio [RR] 0.77; 95% confidence interval [CI] 0.65 to 0.92). A smaller reference vessel diameter at baseline was associated with a higher risk reduction in the restenosis rate (y = −3.551 + 1.826 [x]; p = 0.012). Patients allocated to stent had lower rates of major adverse cardiac events (15.0% vs. 21.8%, p = 0.002; RR 0.70; 95% CI 0.57 to 0.87) and new target vessel revascularizations (12.5% vs. 17.0%, p = 0.004; RR 0.75, 95% CI 0.61 to 0.91). ConclusionsElective stenting is superior to provisional stenting in small coronary arteries. This benefit is more evident in smaller coronary arteries.

Intracoronary stenting and angiographic results: strut thickness effect on restenosis outcome (ISAR-STEREO-2) trial

ObjectivesWe tested the hypothesis that thinner-strut stents are associated with a reduced rate of restenosis when comparing two stents with different design. BackgroundWe have previously shown that, for two stents with similar design, the risk for restenosis is dependent on the strut thickness. It is unknown whether strut thickness preserves its relevance as a determinant of restenosis even in the presence of different stent designs. MethodsA total of 611 patients with symptomatic coronary artery disease were randomly assigned to receive either the thin-strut ACS RX Multilink stent (Guidant, Advanced Cardiovascular Systems, Santa Clara, California) (strut thickness 50 μm, interconnected ring design; n = 309) or the thick-strut BX Velocity stent (Cordis Corp., Miami, Florida) (strut thickness 140 μm, closed cell design; n = 302). The primary end point was angiographic restenosis (≥50% diameter stenosis at follow-up angiography). Secondary end points were the incidence of target-vessel revascularization (TVR) and the combined rate of death and myocardial infarction (MI) at one year. ResultsThe incidence of angiographic restenosis was 17.9% in the thin-strut group and 31.4% in the thick-strut group, relative risk, 0.57 (95% confidence interval, 0.39 to 0.84), p < 0.001. A TVR due to restenosis was required in 12.3% of the thin-strut group and 21.9% of the thick-strut group, relative risk, 0.56 (95% confidence interval, 0.38 to 0.84), p = 0.002. No significant difference was observed in the combined incidence of death and MI at one year. ConclusionsWhen two stents with different design are compared, the stent with thinner struts elicits less angiographic and clinical restenosis than the thicker-strut stent.

Major Ongoing Stroke Trials

Major Ongoing Stroke Trials

Major Ongoing Stroke Trials

Major Ongoing Stroke Trials

Major Ongoing Stroke Trials

Major Ongoing Stroke Trials

Does stent design affect probability of restenosis? A randomized trial comparing Multilink stents with GFX stents

Background Experimental studies have revealed that stent configuration influences intimal hyperplasia. The purpose of this study was to evaluate clinical outcomes for 2 stent designs in a randomized trial with quantitative coronary angiography (QCA) and intravascular ultrasonography (IVUS). Methods We randomly assigned 100 patients with 107 lesions and symptomatic coronary artery disease to deployment of a Multilink stent (Advanced Cardiovascular Systems, Guidant, Santa Clara, Calif) or a GFX stent (Applied Vascular Engineering, Santa Rosa, Calif) with IVUS guidance. QCA and IVUS studies were performed before and after intervention and at follow-up (4.2 ± 1.0 months). Results There were no significant differences in baseline characteristics and QCA and IVUS parameters before and after intervention between the 2 groups. However, minimal lumen diameter at follow-up was significantly larger in the Multilink group (2.46 ± 0.59 vs 2.08 ± 0.79 mm, P <.05). Maximal in-stent intimal hyperplasia was significantly larger in the GFX group (2.9 ± 1.7 vs 1.8 ± 1.2 mm2, P <.01). The restenosis rate differed between the 2 groups (Multilink 4% vs GFX 26%, P =.003). In multiple stepwise logistic regression analysis, the only predictor that significantly correlated with restenosis was stent type (P <.01). The odds ratio for the GFX stent–treated vessels was 18.65 (95% confidence interval 2.10-165.45). Conclusions With deployment of the GFX stent, a thicker neointima develops within the stent. Stent configuration may affect clinical outcomes. (Am Heart J 2001;142:445-51.)

Quantitative Coronary Angiographic and Intravascular Ultrasound Assessment of a New Nonarticulated Stent: Report From the Advanced Cardiovascular Systems MultiLink Stent Pilot Study

Objectives. The purpose of this study was to evaluate the safety, feasibility, optimal deployment technique and 1-year clinical outcome for the Advanced Cardiovascular Systems (ACS) MultiLink stent.Background. Optimal stent deployment assessed by quantitative coronary angiography and intravascular ultrasound (IVUS) is associated with improved clinical outcome.Methods. Forty-nine consecutive patients with a discrete stenosis in a native coronary artery 3 to 4 mm in diameter were treated with the new, balloon-expandable ACS MultiLink stent. Stent expansion was assessed in all patients using quantitative coronary angiography and serial IVUS imaging after 8-, 12- and 16-atm inflations. Clinical follow-up was obtained at 30 days and 1 year.Results. All 49 patients had successful placement of a MultiLink stent without death, emergency coronary artery bypass graft surgery or Q wave myocardial infarction. After placement of the MultiLink stent, the minimal lumen diameter increased from 1.24 to 2.98 mm (p < 0.001), and diameter stenosis decreased from 61% to 7% (p = 0.001). Minimal lumen cross-sectional area by IVUS increased progressively after 8, 12 and 16 atm (5.6 to 6.8 to 7.4 mm2, respectively, p < 0.001). However, only 64% of stents achieved a lumen/reference area ratio ≥70%. No adverse clinical events occurred by 30 days, and by 1 year only one patient (2.0%) required revascularization of the stented artery.Conclusions. Treatment of stenoses in native coronary arteries with the MultiLink stent is associated with a high success rate and a low incidence of adverse events by 1 year, despite the fact that the majority of stents did not meet IVUS-defined criteria for “optimal stenting” derived from first-generation devices.

Bailout stenting for extensive dissection complicating direct infarct angioplasty

Coronary artery dissection is a major cause of abrupt vessel closure, a complication seen in 2% to 10% of balloon angioplasty procedures. Stent implantation has been shown to be an effective treatment of arterial dissection after balloon angioplasty. 1 The stent serves as a metallic scaffold that seals the dissection flap against the arterial wall and maintains patency of the lumen. However, coronary stenting has been believed to be of questionable safety when dissection complicates direct infarct angioplasty because of the fear that placement of a metallic stent at the site of an acute infarction would result in an high rate of stent thrombosis. Two publications describe successful treatment of coronary dissections complicating direct infarct angioplasty with stents. 2, 3 The present report represents a case of extensive dissection and threatened vessel closure after direct infarct balloon angioplasty that was successfully treated by implantation of a Gianturco-Roubin Flex Stent (Cook, Bloomington, Ind.) Unlike the previously reported cases, in this case adjunct thrombolytic therapy was not used. This report adds to the emerging literature regarding bailout coronary stenting as a treatment for selected patients with abrupt or threatened closure after direct infarct angioplasty. A 48-year-old man was admitted to the hospital with an acute anterior myocardial infarction 6 hours after onset of pain. The admission electrocardiogram showed 8 to 10 mm of ST elevation in leads V2 through V6 and 3 mm of ST elevation in leads II, III, and AVF. Bradycardia and near syncope occurred en route to the cardiac catheterization laboratory, where a temporary pacemaker was placed. Cineangiography demonstrated total occlusion of the mid left anterior descending coronary artery and 70% obstruction of the mid right coronary artery. An 8F SL3.5 guide catheter (Medtronic, San Diego, Calif.) was engaged in the left main ostium, and a 0.014-inch Hi-Torque Floppy guide wire (Advanced Cardiovascular Systems, Temecula, Calif.) was advanced across the lesion. Inflation was performed with a 2.5 mm Freehand (Schneider, Minneapolis, Minn.) and then a 3.0 mm Flowtrack balloon (Advanced Cardio

Functional characteristics of a new coronary perfusion balloon: Comparison with the flowtrack 40 in closed chest swine

This study was designed to compare a new investigational coronary perfusion balloon (Wave, Scimed Life Systems Inc.) with that of an approved, widely used, current generation device (Flowtrack 40, Advanced Cardiovascular Systems). Domestic swine were anesthetized with pentobarbital and instrumented using standard percutaneous technique. Left ventricular contractile function (dP/dt) was monitored using a micromanometer while intracoronary and surface ECGs were also recorded. Eight target vessels were studied (4 LAD and 4 Cx) in random order. The perfusion balloons were kept inflated for 10 min. Complete coronary occlusion with a standard angioplasty balloon produced marked decreases in mean aortic pressure, left ventricular developed pressure, peak +dP/dt, peak -dP/dt, and significant ST segment elevation in both intracoronary and surface ECG at 30 seconds. Neither the Wave or Flowtract 40 produced any change in heart rate or mean aortic pressure. Both catheters caused a drop in left ventricular developed pressure immediately after balloon inflation. At 10 min, however, there was a small but significant decrease only with the Flowtrack 40. Similarly, peak +dP/dt was slightly depressed during Flowtrack 40 inflation at 10 min but not with the Wave catheter. Both catheters produced ST segment elevation on the surface and intracoronary electrocardiographic records. These changes were significantly greater with the Flowtrack 40 system. Thus, both the Flowtrack 40 and Wave perfusion balloons are effective in preventing ischemia during coronary occlusion in swine; however, the latter system may be more effective in this model.

Spinal cord protection during thoracoabdominal aneurysm resection

Paraplegia is a devastating complication after thoracoabdominal aneurysm resection. Multi~)le methods of spinal protection have been explored. At present, no reliable method of protecting the spine from ischemic injury exists. I am describing here two cases of thoraco abdominal aneurysm resection with selective cooling of the spinal cord. While the aorta was crossclamped, continuous lavage of the spinal cord with cold normal saline solution was introduced into the subarachnoid space by lumbar puncture. No neurologic sequela developed after crossclamping of the aorta for 58 minutes in case 1 and 36 minutes in case 2. Case 1. A 72-year-old woman was referred to me with a symptomatic thoracoabdominal aneurysm. Angiography showed a large arteriosclerotic aneurysm originating in the distal aortic arch, propagating throughout the thoracic aorta, and involving most of the abdominal aorta below the renal arteries. Spinal cord protection protocol was approved by the Institutional Review Committee of the Rapid City Regional Hospital. On the day of the operation, the patient was taken first to the angio suite for placement of catheters to the subarachnoid space. The procedure was performed with the patient under heavy sedation by an invasive radiologist. The patient was placed prone on a fluoroscopic table with tilt capabilities. The subarachnoid space was entered at the L2-3 level with midline stick with a 20-gauge spinal needle (Fig. 1). The Cook micropuncture system guidewire (Cook Incorporated, Bloomington, Ind.) was then placed through the spinal needle into the subarachnoid space and advanced upward in the midline. After the dilating catheter was positioned ventral within the subarachnoid space, the 0.035 Tad II wire with 0.018 tip (Advanced Cardiovascular Systems, Inc., Santa Clara, Calif.) was passed. The Tad wire is steerable and the 0.018 tip helped avoid damage to nerve roots or cord while the wire was being advanced. The Tad wire was positioned above T5 ventral to the spinal cord. A 5F straight flush catheter was placed over the wire and positioned above T5. By means of the procedure just described, the second 5F catheter was placed at the level of the conus medullaris. The catheter should have four to five additional side holes placed at its tip. The entrance into the subarachnoid space for this second catheter should be, if possible, one level below the entrance of the first catheter. The third catheter was placed at the next inferior level with the tip

Temporary stent as a bail-out device during percutaneous transluminal coronary angioplasty: preliminary clinical experience.

To evaluate the safety and efficacy of a prototype temporary stent (RX Flow Support Catheter, Advanced Cardiovascular Systems) in maintaining coronary perfusion and improving vessel patency in the event of acutely compromised flow complicating percutaneous transluminal coronary angioplasty. Prospective clinical study as part of a multicentre trial. Regional cardiac centre catheterisation laboratory. Eight patients undergoing routine percutaneous transluminal balloon coronary angioplasty in whom coronary artery dissection resulted in impaired coronary artery flow with angina or electrocardiographic ST segment shift, needing bail-out treatment at the time of the procedure. The RX Flow Support Catheter was successfully used and improved coronary flow in all cases, with a reduction in luminal stenosis and resolution of symptoms. The temporary stent was expanded for an average of 85 (range 30-209) minutes. In six patients it was used as a bridge to further treatment (permanent stent in four and coronary artery surgery in two) and two patients did not need further treatment. The temporary stent was safe and effective in the acute management of coronary dissection. The main advantages are its ease and speed of use, and successful restoration of coronary flow both to the distal artery and to affected side branches pending definitive treatment.

In vitro evaluation of blood flow through autoperfusion balloon catheters

The effective flow rates with human blood through an autoperfusion catheter cannot be monitored in vivo and have not been experimentally determined in vitro. The manufacturers (Advanced Cardiovascular Systems [ACS], Temecula, CA) have suggested that "the flow rate" through the Stack over the wire and the RX-60 monorail catheter is 60 ml/min with a pressure gradient of 80 mmHg. We measured human blood flow rates in vitro through these catheters under different continuous pressure regimens (between 40 and 120 mmHg), with varying hematocrit levels (between 25% and 62%). Measured blood flows at a gradient of 80 mmHg were found to vary from 32 to 65 cc/min, with hematocrit levels of 62-25%. Minor variations in the circuitry, besides the viscosity of the medium, cause significant changes in observed flow rates (such as kinking of the catheter and blood sedimentation). In vitro determinations of blood flows cannot automatically be transferred to the in vivo condition, primarily because in vitro determinations do not account for the systolic intramural pressure increase (which may overcome the aortic pressure). If such a phenomenon is also considered, then the in vitro flow rates reported here should be multiplied by a factor of 0.40-0.60 to determine effective in vivo flow rates. Such information is relevant for the clinical operator of angioplasty, especially in the treatment of patients at high risk for undergoing percutaneous transluminal coronary angioplasty.

Interventional cardiology—An overview

Unt i l 10 years ago, cardiac catheterization was predominantly a diagnostic tool for defining anatomic and functional disease states before cardiac surgical correction. After a decade of tentative exploration with the fixed rigid dilator technique of Dotter, balloon dilatation was developed by Andreas Gruentig in 1974 as a treatment for peripheral atherosclerotic stenosis, ushering in the new field of cardiology. The current supplement to the American Journal of Cardiology is based on a symposium that was sponsored by Advanced Cardiovascular Systems in June 1987 to assess the status of this important new field in which the cardiac catheter is used to render definitive treatment of cardiovascular disease, as well as to provide diagnostic data. The centerpiece of interventional cardiology today is percutaneous transluminal coronary angioplasty (PTCA). During the early years of PTCA (1977 through 1981), relatively crude devices and inexperienced operators limited PTCA to patients with proximal, discrete, subtotal stenosis of a single coronary artery (who comprised only 5 to 10% of the population requiring coronary revascularization), and to a primary success rate of only 60%. In contrast, coronary angioplasty is now being applied routinely to patients with more complex coronary anatomic situations, including distal disease, stenosis of multiple vessels, bifurcation lesions, total occlusions, and diseased saphenous vein or internal mammary artery bypass grafts. Concomitant with this expansion in the anatomic capabilities of coronary angioplasty has been a marked broadening of its clinical indications, which now include patients with chronic stable angina, unstable angina, acute myocardial infarction, clinical features that make bypass surgery unacceptable, and a small subgroup of

Cardiac tamponade following perforation of the left anterior descending coronary system during percutaneous transluminal coronary angioplasty: Successful treatment by pericardial drainage

Percutaneous transluminal coronary angioplasty (PTCA) is an effective and increasingly utilized modality in the treatment of coronary artery disease. Its complications include prolonged angina, myocardial infarction, coronary occlusion, dissection, spasm, embolism, and perforation.’ When these complications occur, immediate aortocoronary bypass surgery is usually performed. We report the occurrence of perforation of a diagonal branch of the left coronary artery with associated cardiac tamponade treated successfully in the Cardiac Catheterization Laboratory without surgical repair of the perforated artery. A 69-year-old white man had a 3-week history of chest pain at rest, which was relieved by nitroglycerin. The patient had nonsustained ventricular tachycardia on an otherwise negative exercise thallium examination. Coronary arteriography revealed a 90% stenosis in the mid-left anterior descending coronary artery and multiple areas of noncritical disease in branches of the left circumflex coronary artery (Fig. 1). PTCA of the left anterior descending artery was performed. Following the intra-arterial administration of 10,000 units of heparin, the standard technique employing a No. 9 FL 4 USC1 (USCI, Billerica, Mass.) guiding catheter was used via the right femoral artery. The left anterior descending coronary artery was entered with a standard steerable ACS (Advanced Cardiovascular Systems, Inc., Temeculla, Calif.) guidewire (size 0.014 inch diameter, 175 cm long) and a 2.5 mm ACS dilatation catheter crossed the lesion. Four dilatations, at a maximum pressure of 8 atm and maximum duration of 15 seconds, were performed. In order to better opacify the area of dilatation and in anticipation of the use of a larger-sized dilatation catheter, with the tip of the dilatation catheter held distal to the area of angioplasty, the steerable guidewire was replaced with a 300 cm long ACS exchange guidewire (0.018 inch diameter). The original dilatation catheter was removed. Angiography of the left coronary artery demonstrated successful angioplasty of the left anterior descending lesion and extravasation of contrast into the pericardial cavity at a site near the tip of the exchange guidewire, several centimeters distal to the area of angioplasty and in the area of a small diagonal branch (Fig. 2). The patient was stable hemodynamically,

A newly designed directionally controlled guidewire.

A directionally controlled, 1:1 torque ratio flexible .035" guidewire has been developed for angioplasty procedures being done in the peripheral, renal, subclavian, and visceral circulation. A torque-controlling device is incorporated with the wire in order to negotiate the stenotic or ulcerative atherosclerotic site without damage to the intimal plaque. The increased selectivity of the wire has also found application in subselective examinations within the peripheral, visceral, and extracranial circulation. Four designed configurations are described.