Prevention of distal embolization during coronary angioplasty in saphenous vein grafts and native vessels using porous filter protection.

BACKGROUND: Although distal embolization and the "no-reflow" phenomenon are well described in saphenous vein graft (SVG) interventions, the frequency, magnitude, and characterization of embolized debris have not been evaluated in routine coronary interventions. A unique embolus protection device described herein provides a means of containing and retrieving plaque material dislodged during percutaneous coronary interventions. This report details the first clinical experience of the effectiveness and safety of an emboli protection system in 11 SVG lesions and 15 native coronary artery lesions. METHODS AND RESULTS: The AngioGuard Emboli Capture Guidewire (Cordis) consists of a PTCA wire with an expandable filter at the distal tip. The porous membrane permits normal distal blood flow, while trapping potential emboli by filtration. After crossing the lesion, the filter is expanded, and routine angioplasty is performed over the same wire. Emboli retrieval is achieved by collapsing the filter and retracting the emboli capture wire (ECW). In 26 patients, standard angioplasty was performed over the ECW; 20 of these 26 patients received a stent. Collected debris was sent for histopathological analysis. Plaque debris was retrieved after native coronary and SVG interventions in all cases. The ECW was positioned and retrieved without complications. No major adverse events occurred. Myocardial infarctions and no-reflow were not observed. CONCLUSIONS: The embolization of plaque fragments frequently occurs during coronary and SVG intervention. Distal embolization leading to microvascular obstruction and no-reflow could be successfully minimized by using the ECW.

Initial results of the Quanam drug eluting stent (QuaDS-QP-2) Registry (BARDDS) in human subjects.

Thirty-two patients presenting with varied coronary syndromes and anatomy were treated with a new coronary multisleeve drug delivery coronary stent (QuaDS-QP-2) containing up to 4,000 microg of a taxol-derived lipophilic microtubule inhibitor (QP2). The device was successfully implanted in 32 patients who have been followed for up to 2 years. Twenty-five patients have undergone stress ECHO or SPECT Thallium and all are currently asymptomatic. Thirteen patients have already been restudied angiographically, by IVUS and/or by SPECT Thallium testing and are detailed in this report. Angiographic, IVUS, and SPECT Thallium have been controlled at a mean of 11.2 months (range, 6-15 months) in this 13-patient cohort. Although all 13 QuaDS-QP-2 (QDES) stents were angiographically and IVUS patent, two reinterventions have been required in the 32-patient study group thus far, both relate to either new disease or to distal, small-vessel disease beyond the stent. There was no evidence of significant proliferation in the QDES devices. On the basis of this preliminary data and a European pilot study, a controlled randomized trial (SCORE) is currently in progress in western Europe.

Novel drug-delivery stent: intravascular ultrasound observations from the first human experience with the QP2-eluting polymer stent system.

BACKGROUND: The aim of this study was to use serial intravascular ultrasound (IVUS) to evaluate the long-term effect of stent-based 7-hexanoyltaxol (QP2, a taxane analogue) delivery on neointimal tissue growth within the stent and on vessel dimensions at the adjacent reference segments. METHODS AND RESULTS: Serial IVUS analyses (immediately after intervention and at follow-up at 8.3 months) were performed in 15 native coronary lesions treated with the QuaDS-QP2 stent. IVUS measurements were performed at 8 cross-sections in each target segment (4 cross-sections within the stent and 2 cross-sections in each reference segment). At baseline, no significant plaque protrusion or thrombus was detected in the target segment. Mild incomplete stent apposition and edge dissection were observed in one and two cases, respectively. Percent expansion of the stent (minimum stent area/average reference lumen area) was 96.0+/-21.7%. At follow-up, mean neointimal area within the stent was 1.2+/-1.3 mm(2), and mean cross-sectional narrowing (neointimal area/stent area) was 13.6+/-14.9%. At the vessel segments immediately adjacent to the stent, a significant increase in plaque area (1.9+/-2.6 mm(2), P=0.001) was observed, but vessel area remained unchanged. However, no patients showed clinically significant in-stent or edge restenosis (diameter stenosis >/=50%) during the follow-up period. CONCLUSIONS: The first human experience with the new drug-delivery stent showed a minimal amount of neointimal proliferation in the stented segment. Late lumen loss at the reference sites adjacent to the stent was acceptable and predominantly due to plaque proliferation.

Evaluation of the percutaneous intramyocardial injection for local myocardial treatment.

Therapeutic angiogenesis requires the induction of new blood vessel formation for the treatment of peripheral vascular and coronary artery disease. Efficacious application of this new therapy requires optimizing multiple factors, including the therapeutic agent, dosing, frequency of administration, and delivery modality. In this study, a helical needle drug infusion catheter was applied for optimal application of percutaneous intramyocardial delivery (PIMD). (125)Iodine-labeled albumin was injected by PIMD into the left ventricle myocardium in eight swine. After 1 hr, PIMD resulted in a high concentration of radiolabel at the treatment site; 16.4% +/- 2.1% of delivered and 81.4% +/- 2.6% of the total cardiac activity was concentrated at the site of delivery. The depth of needle penetration correlated with the myocardial retention of delivered protein. The myocardial retention of radiolabel in animals with shallow injections was 10.1% +/- 0.8%, compared to 18.9% +/- 3.3% retention after deep injections. The specific activity at the treatment site (radioactive counts per gram of tissue) was 115 +/- 36, 226 +/- 55, and 47 +/- 10 times higher compared to liver, lung, and kidney, respectively. Continuous coronary sinus and aortic blood sampling indicates that within 15 min following intramyocardial injection, a significant amount of nonretained protein is found within the coronary sinus. This study defines some of the parameters that can affect optimal application of PIMD and demonstrates that PIMD is a safe and efficient method for local drug delivery.

Coronary stents: In vitro aspects of an angiographic and ultrasound quantification with in vivo correlation.

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.

The stent decade: 1987 to 1997. Stanford Stent Summit faculty.

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.

Coronary AVE micro stents: serial quantitative angiography and histology in a canine model.

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 <30% in all animals. Histologically, a peak of inflammation was visible at 2 weeks; however, the extent of luminal narrowing reached its peak at 8 weeks and the lumen dimension increased somewhat at 24 weeks. The degree of intimal thickening remained relatively constant throughout the different time points (<200 microm). Overall, these data suggest that constrictive remodeling within the stented segment occurs at 8 weeks in this animal model. The later increase of the stented segment dimensions as well as higher net gain at 24 weeks compared to 8 weeks after deployment suggests that this constriction is a transitory phenomenon.

High-speed rotational atherectomy: six-month serial quantitative coronary angiographic follow-up.

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, p<0.01, with decrease of type C lesions from 54.8 percent to 30.8 percent, p<0.05. Comparison of the degree of the net gain (NG) showed more severe baseline lesions in the high-gain group (NG >20 percent) compared with the moderate-gain group (20 percent > NG > 0 percent) and to the loss group (minimal luminal diameter [MLD] 0.8 +/- 0.4 mm vs 1.0 +/ 0.4 mm, p<0.05; and 1.2 +/- 0.5 mm; p<0.01, respectively). Highest initial gain (36.5 percent +/- 26.2 percent vs 24.5 percent +/- 18.1 percent; p<0.015; and 19.0 percent +/- 23.2 percent; p<0.001) as well as lowest late loss (1.8 percent +/- 21.7 percent vs 14.0 percent +/-18.4 percent; p<0.01 and 28.1 percent +/- 25.0 percent; p<0.01) were found in the high NG group. A higher interaction between burr and atheroma resulted in the lowest restenosis rate of 6 percent.

Multicenter clinical experience with the development of a novel short coronary stent and its prototype device.

Our initial experience with the Micro Stent PL and its prototype intracoronary stent is described. A total of 206 stents were implanted in 84 patients for threatened closure or restenosis following balloon angioplasty. The stenting procedure was successful and uncomplicated in 83 of 84 patients. Potential advantages of this particular stent relate to its short length, low surface area, expandability over a range of diameters, radiopacity, low profile, and ease of delivery.

Outcome of narrowing related side branches after high-speed rotational atherectomy.

High-speed rotational atherectomy (HSRA) is advocated for calcified and diffusely narrowed coronary arteries. There are often side branches involving these kinds of lesions. The presence of significant lesion-related side branches has been considered a relative contraindication to rotational atherectomy. This study was performed to determine the rate, predictors, and outcome of side branch occlusion after HSRA. The angiograms of 418 patients were examined with 320 side branches in 240 target vessels of > or = 1 mm in diameter being identified. Vessels were scored as either perfused (Thrombolysis In Myocardial Infarction 2 or 3 flow) or occluded (Thrombolysis In Myocardial Infarction 0 or 1 flow before and after the procedure. A detailed quantitative angiographic analysis was performed on a total of 108 side branches including all cases of branch occlusion. Clinical outcomes were determined in all cases with side branch loss. There were 24 occlusions in 21 patients after the procedure, giving a rate of branch loss of 7.5%. Follow-up angiography of > or = 24 hours was available for 13 of the occluded branches and 12 were found to be patent. In the 21 patients with branch occlusion, 6 sustained a myocardial infarct (of which 5 were non-Q-wave), 2 underwent coronary artery bypass grafting, and 2 died. There are frequently lesion-associated side branches in the types of vessels to undergo HSRA. These branches remained patent 92.5% of the time, with occlusion occurring infrequently and usually being transient. When occlusion did occur, there was a 29% incidence of myocardial infarction.

Effects of technique modification on immediate results of high speed rotational atherectomy in 710 procedures on 656 patients.

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 (< or = 2 ATM) balloon angioplasty (LP BA) was performed in 221 patients (31%), and HSRA with adjunctive high pressure (> or = 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.

Acute clinical and angiographic results with the new AVE Micro coronary stent in bailout management.

To determine the feasibility and safety of development of this new stent, we deployed 28 AVE Micro stents in 23 native coronary artery lesions in 20 patients who developed acute or threatened closure after balloon angioplasty (BA). Ten stents were deployed in the left anterior descending artery, 10 in the circumflex, and 8 in the right coronary artery. Luminal dimensions were measured using a computer-based quantitative coronary angiographic analysis system (CAAS II). Stent deployment was successful in 27 of 28 attempts (96%). In 1 patient with a threatened closure of the left anterior descending artery associated with proximal vessel tortuosity, attempted stent deployment was unsuccessful. The clinical course of the other 19 patients in whom stent deployment was successful was free of coronary reintervention, bypass surgery, and death. A myocardial infarction was observed in 2 patients (10%), in 1 of whom the stent was implanted within 24 hours after the onset of acute myocardial infarction, and in the other acute vessel occlusion was present for 58 minutes before stent implantation. No subacute occlusion was observed. Event-free survival at 30 days after stent implantation was 85% (17 of 20 patients). Minimal luminal diameter was 0.85 +/- 0.57 mm before and 1.19 +/- 0.66 mm after BA, 2.61 +/- 0.39 mm during balloon inflation, 3.26 +/- 0.46 mm during and 2.74 +/- 0.51 mm after stenting, 3.43 +/- 0.52 mm during balloon inflation after stenting (Swiss Kiss), and 2.85 +/- 0.48 mm after Swiss Kiss.(ABSTRACT TRUNCATED AT 250 WORDS)

Quantitative left ventriculography: methods of assessment of the regional contractility.

To compare different approaches to the quantitative analysis of regional left ventricular (LV) function, six different protocols with various long axis definitions, with or without alignment, with radial or hemiaxial segmental definitions were used. Study group consisted of 20 patients with single vessel coronary artery disease after Q-wave anterior myocardial infarction (MI) and 20 patients after Q-wave diaphragmatic MI. Control group consisted of 100 patients. Analytic protocol with the long axis drawn between the apex of the LV and the center of aortic valve plane, radial coordinate system originating from the midpoint of the long axis and alignment of the long axes in systole and diastole, was found to be most sensitive and specific for detection of both anterior and diaphragmatic contraction abnormalities. Original method to measure both severity and length of the regional contraction abnormality is suggested.

Comparative study of the angiographic morphology of coronary artery lesions treated with PTCA, directional coronary atherectomy, or high-speed rotational ablation.

To evaluate trends in morphology-based intervention selection, series of 110 consecutive procedures of each of three devices, percutaneous transluminal balloon coronary angioplasty (PTCA), directional coronary atherectomy (DCA), or high-speed rotational ablation (HSRA), were reviewed. PTCA was used mainly in discrete, concentric, smooth, ACC/AHA type A and B1 lesions. PTCA was used less frequently on a bend, branching points or in calcified lesions. Using PTCA as a reference, DCA was used more often for the treatment of discrete, proximal, eccentric, and noncalcified lesions, often complicated with thrombus and located on straight segments. HSRA was used more frequently in diffuse, calcified multiple complicated and B2+C type lesions with frequent side branches and bend points. These results suggest that directional atherectomy and rotational ablation may be helpful in expanding the capacity of the operator to approach prognostically unfavorable lesions.

Triple vessel revascularization: coronary angioplasty versus coronary artery bypass surgery: initial results and five-year follow-up. Comparative costs and loss of working days and wages.

OBJECTIVES: The purpose of this study was to compare early and late outcomes in patients undergoing PTCA or CABG for triple vessel disease. BACKGROUND: Although early results of PTCA/CABG randomized trials have recently become available, at present little data exists on long-term medical and socioeconomic effects of these treatment modalities in patients with triple vessel revascularization. METHODS: During 1986-87, 76 patients undergoing triple vessel PTCA and 85 patients having triple vessel CABG were selected from a consecutive series of patients having multivessel revascularization. Initial results and 5 year outcome, hospital stay and charges and out-of-work time were assessed from prospectively collected data. RESULTS: Clinical and morphological factors were similar in the PTCA and CABG groups. Hospital success and complications were also similar, except for higher mortality in the CABG cohort (0 vs. 3.5%). Five year follow-up showed no differences in survival, nonfatal infarction and angina-free status; however, there was a difference in need for repeat revascularization (PTCA 55.4% vs. CABG 6.3%, p less than 0.001). Repeat PTCA accounted for 49% of the revascularization in the PTCA cohort. Crossovers were similar (PTCA[CABG 6.8%; CABG[PTCA 6.3%, pNS). Predictors of late death in the entire population were female gender (p less than 0.0001), diabetes (p<0.05) and depressed LVEF (p less than 0.05). The choice of revascularization procedure (PTCA vs. CABG) was not an independent predictor of late death or MI. Analysis of initial hospital charges showed a 2:1 advantage in favor of PTCA but this advantage was lost in late followup due to the need for repeat revascularization in the PTCA group. However, the PTCA cohort lost fewer working days than CABG patients (3017 vs 5874 days) and therefore, lost less wages ($7,022 vs. $14,685). CONCLUSIONS: The study shows that for selected triple vessel disease patients, PTCA and CABG results are comparable after 5 years, though repeat revascularization (mainly due to restenosis) was necessary in the PTCA group to maintain these favorable results. After 5 years, hospital charges are similar in the 2 groups, though out-of-work time and lost wages were 2:1 in favor of PTCA.

Coronary stenting with a new ultra-short balloon expandable device: early and late animal results.

The early and late effects of a new balloon-expandable coronary stent (Boneau II) were studied in 16 adult mongrel dogs. Thirty-three balloon-expandable stents were deployed using standard transfemoral coronary angioplasty technique. Single stents were placed in eight dogs and multiple (two to four) stents were placed in eight dogs. Intravenous heparin (3,000 units) was administered at the beginning of the procedure. Aspirin, dipyridamole, dextran, and warfarin were not administered before or after the procedure. All stent deployments were successful. Angiographic or pathologic examinations were performed within 24 hr of deployment on two of the dogs, at 2 weeks on two of the dogs, at 2 months on three of the dogs, at 6 months on six of the dogs, and at 1 year on three of the dogs. All successfully deployed stents were noted to be widely patent. There was no evidence of side-branch vessel occlusion. There was no evidence of acute or late vessel thrombosis. Histologic examination at 2 months showed a mean intimal thickness of 153 microns. The stainless steel Boneau II coronary stent is relatively short and easily deployed. This balloon-expandable coronary stent was successfully deployed in normal canine arteries without the use of anticoagulation or antiplatelet therapy before or after the procedure. The Boneau II intracoronary stent has a very low thrombogenic potential in dogs.

Late outcome of multivessel coronary artery disease after angioplasty or bypass surgery.

Background. Results from randomized trials to determine optimal treatment for patients with multivessel coronary disease are not yet available. Thus, the early and late outcomes of 191 PTCA and 221 CABG patients done in 1985-86 were evaluated. Methods and Results. CABG patients selected had more coronary risk factors and more severe coronary artery disease compared to PTCA patients. Comparison of the initial outcome showed that clinical success without major cardiovascular events was similar (93.7% for PTCA vs. 90.0% for CABG; p=n.s.). Five year followup was obtained in 99.0% of PTCA patients and 94.4% of CABG patients. In the PTCA group, 89.8% were alive, 4.8% had sustained an MI, and repeat revascularization was required in 46.8%. In the CABG group, 87.1% were alive, 3.2% had had a MI, and 3.5% required repeat revascularization. Statistical comparison demonstrated no difference between the groups in survival or late cardiac events, but rate of repeat revascularization was significantly higher for PTCA patients (p less than 0.0001). Incompleteness of revascularization (p<0.01) was independently associated with an increased need for repeat revascularization in the PTCA group. In the CABG group, depressed left ventricular function (p less than 0.001) and female sex (p<0.01) were associated with lower survival rates. An analysis of cost per patient showed that the strategies were comparable. Conclusions. PTCA and CABG in multivessel disease patients have similar early results and comparable rates of survival and late cardiac events. Significantly more repeat revascularization is required in PTCA patients to maintain these results.(ABSTRACT TRUNCATED AT 250 WORDS)