Laser Coronary Angioplasty Research Articles

Six month outcome and determinants of adverse clinical events after successful excimer laser coronary angioplasty: Lloyd W. Klein, Frank Litvack, David Holmes, James Margolis, Donald Rothbaum, Frank Cummins, Neil Eigler, William O'Neill, for the ELCA A.I.S. Multicenter Registry. Rush Heart Institute, Rush-Presbyterian-St. Luke's Medical Center, Jelke Pavilion, Chicago, IL J Invas Cardiol 1995;7:191–9

Six month outcome and determinants of adverse clinical events after successful excimer laser coronary angioplasty: Lloyd W. Klein, Frank Litvack, David Holmes, James Margolis, Donald Rothbaum, Frank Cummins, Neil Eigler, William O'Neill, for the ELCA A.I.S. Multicenter Registry. Rush Heart Institute, Rush-Presbyterian-St. Luke's Medical Center, Jelke Pavilion, Chicago, IL J Invas Cardiol 1995;7:191–9

Predictors of restenosis after excimer laser coronary angioplasty: Z.M.B. Ghazzal, E. Burton, W.S. Weintraub, F. Litvack, DA Rothbaum, L. Klein, S.B. King III. Emory University Hospital, Atlanta, GA. Am J Cardiol 1995;75:1012–4

Predictors of restenosis after excimer laser coronary angioplasty: Z.M.B. Ghazzal, E. Burton, W.S. Weintraub, F. Litvack, DA Rothbaum, L. Klein, S.B. King III. Emory University Hospital, Atlanta, GA. Am J Cardiol 1995;75:1012–4

Effect of intracoronary saline infusion on dissection during excimer laser coronary angioplasty: A randomized trial: L.I. Deckelbaum, M.K. Natarajan, J.A. Bittl, K. Rohlfs, J. Scott, R. Chisholm, K.A. Bowman, B.H. Strauss. Section of Cardiology, West Haven VA Medical Center, Yale University School of Medicine, West Haven, CT. J Am Coll Cardiol 1995;26:1264–9

Effect of intracoronary saline infusion on dissection during excimer laser coronary angioplasty: A randomized trial: L.I. Deckelbaum, M.K. Natarajan, J.A. Bittl, K. Rohlfs, J. Scott, R. Chisholm, K.A. Bowman, B.H. Strauss. Section of Cardiology, West Haven VA Medical Center, Yale University School of Medicine, West Haven, CT. J Am Coll Cardiol 1995;26:1264–9

Usefulness of a prototype directional catheter for excimer laser coronary angioplasty in narrowings unfavorable for conventional excimer or balloon angioplasty: E. Rechavia, J. Federman, A. Shefer, G. Macko, N.L. Eigler, F. Litvack. Cardiovascular Intervention Center, Cedars-Sinai Medical Center, Los Angeles, CA. Am J Cardiol 1995; 76:1144–6

Usefulness of a prototype directional catheter for excimer laser coronary angioplasty in narrowings unfavorable for conventional excimer or balloon angioplasty: E. Rechavia, J. Federman, A. Shefer, G. Macko, N.L. Eigler, F. Litvack. Cardiovascular Intervention Center, Cedars-Sinai Medical Center, Los Angeles, CA. Am J Cardiol 1995; 76:1144–6

Comparison of tissue disruption caused by excimer and midinfrared lasers in clinical simulation

Laser coronary angioplasty is a useful therapy for selected complex coronary lesions. Laser-induced acoustic trauma is postulated to be a cause of dissection and acute vessel occlusion. Controversy exists regarding the relative degree of photoacoustic effects of midinfrared and excimer lasers in clinical practice. To date, these systems have not been compared at clinical energy doses and with clinical pulsing strategies. Therefore, we studied the photoacoustic effects of both midinfrared and excimer lasing at clinically accepted doses. Human atherosclerotic iliofemoral artery segments were obtained at autopsy (n = 36) and placed lumen side up in a saline bath. Clinical laser catheters were advanced over an 0.018′ guide wire, perpendicular to the tissue. A 10-g down force was applied to the catheter for full-thickness lasing. Pulsing strategies were, for midinfrared laser: 5 pulses, 1-sec pause, 5 pulses, 1-sec pause, 5 pulses, withdraw; for excimer: 5 sec of pulses, wait 10 sec, 5 sec of pulses. Several clinically acceptable energy levels were used; for excimer: 25 mJ/mm2, 40 mJ/mm2, 60 mJ/mm2; for midinfrared: 3 W (400 mJ/mm2), 3.5 W (467 mJ/mm2). Photoacoustic effect was assessed histologically by determining the number of lateral cleavage planes (dissections) arising from the lased crater border and extending into the surrounding tissue. In normal tissue, midinfrared lasing produced less acoustic damage than excimer lasing (2.79 ± 0.78 vs. 5.27 ± 0.75 cleavage planes, mean ± SD, P < 0.05, data for lowest energy for each system). The same was true in noncalcified atheroma (2.48 ± 0.71 vs. 6.43 ± 1.09, P < 0.05) and calcified atheroma (2.47 ± 1.21 vs. 6.27 ± 1.13, P < 0.05). This effect was similar at all energy levels, with a trend for more damage at higher energies in both systems. This study demonstrates that midinfrared lasing causes less acoustic damage than excimer lasing when using clinical catheters, energy levels, and pulsing strategies. This effect is independent of tissue-type but tends to be dose-related. These findings may explain, in part, the differences in dissection rates seen clinically. © 1996 Wiley-Liss, Inc.

Comparison of tissue disruption caused by excimer and midinfrared lasers in clinical simulation

Laser coronary angioplasty is a useful therapy for selected complex coronary lesions. Laser-induced acoustic trauma is postulated to be a cause of dissection and acute vessel occlusion. Controversy exists regarding the relative degree of photoacoustic effects of midinfrared and excimer lasers in clinical practice. To date, these systems have not been compared at clinical energy doses and with clinical pulsing strategies. Therefore, we studied the photoacoustic effects of both midinfrared and excimer lasing at clinically accepted doses. Human atherosclerotic iliofemoral artery segments were obtained at autopsy (n = 36) and placed lumen side up in a saline bath. Clinical laser catheters were advanced over an 0.018" guide wire, perpendicular to the tissue. A 10-g down force was applied to the catheter for full-thickness lasing. Pulsing strategies were, for midinfrared laser: 5 pulses, 1-sec pause, 5 pulses, 1-sec pause, 5 pulses, withdraw; for excimer: 5 sec of pulses, wait 10 sec, 5 sec of pulses. Several clinically acceptable energy levels were used; for excimer: 25 mJ/mm2, 40 mJ/mm2, 60 mJ/mm2; for midinfrared: 3 W (400 mJ/mm2), 3.5 W (467 mJ/mm2). Photoacoustic effect was assessed histologically by determining the number of lateral cleavage planes (dissections) arising from the lased crater border and extending into the surrounding tissue. In normal tissue, midinfrared lasing produced less acoustic damage than excimer lasing (2.79 +/- 0.78 vs. 5.27 +/- 0.75 cleavage planes, mean +/- SD, P < 0.05, data for lowest energy for each system). The same was true in noncalcified atheroma (2.48 +/- 0.71 vs. 6.43 +/- 1.09, P < 0.05) and calcified atheroma (2.47 +/- 1.21 vs. 6.27 +/- 1.13, P < 0.05). This effect was similar at all energy levels, with a trend for more damage at higher energies in both systems. This study demonstrates that midinfrared lasing causes less acoustic damage than excimer lasing when using clinical catheters, energy levels, and pulsing strategies. This effect is independent of tissue-type but tends to be dose-related. These findings may explain, in part, the differences in dissection rates seen clinically.

Coronary Intervention with the Excimer Laser: A Current Perspective

One variety of the excimer coronary laser system (Advanced Interventional Systems) has been available for use in selected clinical centers from 1989 through 1995. This over‐the‐wire catheter‐laser system uses a 308‐nm laser and requires prepositioning of a 0.014′’to 0.018′’guidewire across the target stenosis. Development of the coronary laser system was stimulated by the limitations of conventional angioplasty, which have included abrupt reclosure, coronary dissection, restenosis, and chronic total occlusion. The excimer coronary laser angioplasty (ELCA) registry includes nearly 4,000 patients who have undergone attempted laser angioplasty. A success rate comparable to standard balloon angioplasty and an acceptably low complication rate were achieved in this registry database. While laser angioplasty has been promoted for long, diffuse lesions, total occlusions, lesions with substantial side branch involvement, and a possible therapy to reduce the incidence of restenosis, the highly selected nature of patients enrolled in the registry prevents any definite conclusions regarding the utility of intracoronary laser in these potential indications. Additionally, the advent of newer technologies, including rotablator and stenting, may further erode any potential advantages of coronary laser angioplasty. Randomized trials of newer interventional devices will be required to determine their true value and clinical utility. (J Interven Cardiol 1996;9:175–178)

Angiographic Results and Elastic Recoil Following Coronary Excimer Laser Angioplasty with Saline Perfusion

Recent experiments have demonstrated that pressure waves of several hundred atmospheres, which occur during excimer laser coronary angioplasty (ELCA), are reduced while ablating in saline in comparison to blood or contrast medium. We report the procedural outcome of ELCA (XeCI laser operating at 308 nm, 25–40 Hz, 40–60 mJ/mm2 fluence, and 135 nsec/pulse) performed with a modified saline infusion protocol (two operator technique, flush, and continuous application of saline through the guiding catheter immediately prior and during the whole losing procedure). We studied 48 patients (34 males, 14 females; mean age: 61 ± 6 years; 18 occlusions, 30 stenoses [&gt; 60% diameter stenosis]) with 10 type A, 17 type B, and 21 type C lesions. Laser success (&gt; 20% increase in minimal luminal diameter [MLD]) was achieved in 41 patients (85.4%), and procedural success (&lt; 50% residual stenosis) in 44 patients (91.6%). The MLD increased from 0.37 ± 0.12 to 1.63 ± 0.35 mm (P &lt; 0.001) following laser ablation, and to 2.30 ± 0.34 mm (P &gt; 0.01) after percutaneous transluminal coronary angioplasty (PTCA). The mean percentage stenosis decreased from 81%± 6% (baseline) to 48%± 12% (P &lt; 0.001) after laser ablation, and to 29%± 10% (P &lt; 0.01) following PTCA. The mean diameter of the laser‐catheter (LC) was 1.54 ± 0.2 and the mean diameter of the inflated balloon at maximum pressure was 2.7 ± 0.25 mm. Thus, the elastic recoil (ER) following balloon deflation was 15%± 9%, and below the reported ER for PTCA. Two major dissections occurred following ELCA; one patient required bypass surgery and developed a Q wave myocardial infarction (Ml), and one patient was successfully treated with stent implantation following abrupt closure. There were no in‐hospital deaths, further Q wave MIs, and/or perforation. In conclusion, ELCA with concomitant saline infusion is effective, safe, and easy to perform. The use of this ablation procedure reduces the rate of significant dissections, favors effective tissue ablation, and thus may in part be responsible for a reduced amount of elastic recoil following additional balloon angioplasty. (J Interven Cardiol 1996;9:9–18)

Intravascular ultrasound findings after excimer laser coronary angioplasty.

Intravascular ultrasound (IVUS) was used to study 104 lesions in 98 patients after excimer laser coronary angioplasty (ELCA). Lesion site external elastic membrane (EEM) and lumen cross-sectional areas (CSA) were measured; plaque+media (P+M = EEM - lumen) CSA and percentage of cross-sectional narrowing (CSN = P+M CSA/EEM CSA) were calculated; and the results were compared to a reference site. The lumen CSA (2.6 +/- 1.0 mm2) averaged 24% larger than the cross-sectional area of the largest laser catheter used, and 64 lesions (62%) fit the definition of arterial expansion (lesion EEM CSA > reference site EEM CSA). The residual percentage of cross-sectional narrowing averaged 83.8 +/- 8.8%. Dissections were present in 44% of lesions, and were more common in lesions with superficial calcium (59%) than in lesions with only deep calcium (31%) or no calcium (20%, P = 0.0102). Dissections of superficial calcified plaque had an unusual "shattered" or "fragmented" appearance. These findings suggest that excimer laser angioplasty causes forced vessel expansion with dissection, but limited atheroablation.

Randomised trial of excimer laser angioplasty versus balloon angioplasty for treatment of obstructive coronary artery disease

Summary Background Excimer laser coronary angioplasty is reported to give excellent procedural results for treatment of complex coronary lesions, but this method has not been compared with balloon angioplasty in a randomised trial. Methods Patients (n=308) with stable angina and coronary lesions longer than 10 mm on visual assessment were included. 151 patients (158 lesions) were assigned randomly to laser angioplasty and 157 (167 lesions) to balloon angioplasty. The primary clinical endpoints were death, myocardial infarction, coronary bypass surgery, or repeat coronary angioplasty of the randomised segment during 6 months of follow-up. The primary angiographic end-point was the minimal lumen diameter at follow-up in relation to the baseline value (net gain), as determined by quantitative coronary angiography. Findings Laser angioplasty was followed by balloon angioplasty in 98% of procedures. The angiographic success rate was 80% in patients treated with laser angioplasty compared with 79% in patients treated with balloon angioplasty. There were no deaths. Myocardial infarction, coronary bypass surgery, and repeat angioplasty occurred in 4·6%, 10·6%, and 21·2%, respectively, of the patients in the laser angioplasty group compared with 5·7%, 10·8%, and 18·5% of the balloon angioplasty group. Net mean (SD) gain in minimal lumen diameter was 0·40 (0·69) mm in patients treated with laser angioplasty and 0·48 (0·66) mm in those treated with balloon angioplasty (p=0·34). The restenosis rate (>50% diameter stenosis) was 51·6% in the laser angioplasty group versus 41·3% in the balloon angioplasty group (p=0·13). Interpretation Excimer laser angioplasty followed by balloon angioplasty provides no benefit additional to balloon angioplasty alone with respect to the initial and long-term clinical and angiographic outcome in the treatment of obstructive coronary artery disease.

Mechanisms of lumen enlargement after excimer laser coronary angioplasty. An intravascular ultrasound study.

The mechanisms of excimer laser coronary angioplasty (ELCA) have never been studied in human coronary arteries in vivo. ELCA was used to treat 202 lesions in 190 patients. Forty-nine lesions in 48 patients were studied by use of sequential (before and after ELCA and after adjunctive device therapy) intravascular ultrasound (IVUS). External elastic membrane (EEM), lumen, and plaque+media (P+M = EEM-lumen) cross-sectional areas (CSAs) and lesion arcs of calcium were measured before and after ELCA and after adjunct device use. Lumen improvement after ELCA (1.4 +/- 0.5 to 2.7 +/- 0.8 mm2) was the result of both tissue ablation (decrease in P+M CSA from 16.8 +/- 7.1 to 15.9 +/- 6.7 mm2, P < .0001) and vessel expansion (increase in EEM CSA from 18.2 +/- 7.1 to 18.6 +/- 6.8 mm2, P = .0245), with no change in calcium. The decrease in P+M CSA was 39% of the CSA of the laser catheter used. Dissections were present in 39% of lesions, 84% within superficial calcium; fibrocalcific deposits developed a "fragmented" appearance. ELCA increased lumen CSA by both atheroablation and vessel expansion without calcium ablation. Superficial fibrocalcific deposits developed a characteristic fragmented appearance. These findings support both photoablation and forced vessel expansion as mechanisms of lumen enlargement and plaque dissection after ELCA.

Coronary laser angioplasty.

Balloon angioplasty was introduced among the armament of therapy for coronary heart disease in 1977 by Gruentzig in Zurich. Since the first case was successful, this method of treatment spread out rapidly so that at the present time, more than 400,000 procedures are being performed per year in the U.S. The reasons for such on explosive success includes the relative safety of the procedure, the reduction in cost as compared to surgical bypass procedures, the short in-hospital stay, and short recovery time.

Usefulness of a prototype directional catheter for excimer laser coronary angioplasty in narrowings unfavorable for conventional excimer or balloon angioplasty

We report clinical and angiographic results in 53 patients with 57 significant coronary or saphenous vein graft narrowings treated with directional excimer laser angioplasty. The target vessels were the left main (1%), anterior descending (32%), circumflex (19%), right coronary artery (39%), and vein grafts (9%). Lesions were morphologic class B1 (18%), B2 (79%), or C (3%), with 40 de novo and 17 restenotic lesions. Adjunctive balloon angioplasty was used in 53 lesions (93%). Mean pre- and postprocedural minimal lumen diameters were 0.6 ± 0.3 and 1.9 ± 0.7 mm (p < 0.001), corresponding to a mean diameter stenosis of 72 ± 20% and 27 ± 16%. Procedural success rate was 91%. Cumulative risk of death, Q-wave myocardial infarction, or emergency bypass operation was 9% (5 patients). Of patients who had a successful laser procedure, 28 (60%) with 30 lesions underwent angiographic follow-up at 6 ± 3 months after the procedure. Restenosis rates (>50% diameter restenosis or acute gain loss) were 37% and 23%, respectively. Four patients underwent bypass, 3 angioplasty, and 1 patient died from cancer. This study demonstrates the feasibility of directional application of laser energy to selected unfavorable narrowings for conventional excimer laser or balloon angioplasty. Further evaluation of this device using the now standard saline infusion technique is necessary to establish its ultimate role as a primary interventional device.

Effect of intracoronary saline infusion on dissection during excimer laser coronary angioplasty: A randomized trial

We sought to evaluate whether intracoronary saline infusion during excimer laser coronary angioplasty decreases the incidence of significant laser-induced coronary artery dissections. Despite procedural success rates > 90%, coronary artery dissections occur in 17% to 27% of excimer laser coronary angioplasty procedures. Excimer laser irradiation of blood results in vapor bubble formation and acoustomechanical trauma to the vessel wall. Saline infusion into a coronary artery may minimize blood irradiation and consequent arterial wall damage. In this prospective, randomized, controlled study, consecutive patients undergoing excimer laser coronary angioplasty were randomly assigned to conventional laser irradiation in a blood medium or to laser irradiation with blood displacement by intracoronary saline infusion. In the patients randomized to intracoronary saline infusion, prewarmed normal saline was injected through the coronary artery guide catheter at a rate of 1 to 2 ml/s using a power injector. The incidence and severity of dissection after excimer laser ablation were evaluated in a core laboratory by angiographers with no knowledge of treatment assignment. The severity of coronary artery dissection was rated on an ordinal scale of 1 to 5. Dissections of grade 2 or higher were considered significant. The mean (+/- SE) dissection grade after laser angioplasty in patients treated with intracoronary saline infusion was 0.43 +/- 0.13 compared with 0.91 +/- 0.26 in patients undergoing laser angioplasty in a blood medium. The incidence of significant dissection was 7% in saline-treated patients compared with 24% in conventionally treated patients (p < 0.05). No significant complications were associated with saline infusion. Intracoronary saline infusion should be incorporated into all excimer laser coronary angioplasty procedures.

Immediate and late outcome of excimer laser and balloon coronary angioplasty: A quantitative angiographic comparison based on matched lesions

This study sought to compare acute lumen changes and late lumen narrowing during and after excimer laser-assisted balloon angioplasty, measured by quantitative coronary angiography, with the immediate and long-term outcome of balloon angioplasty alone. Although excimer laser coronary angioplasty is used as an adjunct or alternative to balloon angioplasty, limited comparative data exist regarding the immediate and long-term efficacy of excimer laser-assisted balloon angioplasty versus balloon angioplasty alone. A series of 53 lesions in 47 consecutive patients successfully treated with excimer laser-assisted balloon angioplasty were individually matched after completion of 6-month follow-up angiography with 53 successfully treated balloon angioplasty lesions according to vessel location, preprocedural minimal lumen diameter and reference diameter. Immediate and long-term angiographic results were assessed by an automated lumen contour detection algorithm. Before intervention in the laser and balloon angioplasty groups, respectively, minimal lumen diameter (mean +/- SD) was 0.73 +/- 0.47 and 0.74 +/- 0.46 mm, and reference diameter was 2.71 +/- 0.42 and 2.72 +/- 0.41 mm. Laser angioplasty was followed by adjunctive balloon dilation in 50 lesions. Mean balloon diameter at maximal inflation was similar in both treatment groups (2.61 +/- 0.32 and 2.65 +/- 0.38 mm, respectively), resulting in similar minimal lumen diameters after intervention of 1.77 +/- 0.41 and 1.78 +/- 0.34 mm, respectively. At follow-up angiography, minimal lumen diameter after excimer laser-assisted balloon angioplasty was 1.17 +/- 0.63 mm, and that after balloon angioplasty alone was 1.46 +/- 0.67 mm (p = 0.02). The angiographic restenosis rates at follow-up using the 50% diameter stenosis cutoff criterion were 57% and 34%, respectively (p = 0.02). Quantitative angiographic analysis of a matched group of 106 successfully treated coronary lesions showed a similar immediate outcome but reduced long-term efficacy of excimer laser-assisted balloon angioplasty compared with that after balloon angioplasty alone.

Solid-State, Pulsed-Wave, Mid-Infrared Coronary Laser Angioplasty in de Novo versus Restenosis Lesions: Observations from a Multicenter Study

The following is a study of the response of de novo versus restenosis coronary lesions to pulsed-wave, mid-infrared (holmium:YAG) laser assisted angioplasty. De novo lesions contain thrombi, cholesterol, and fibrosis, whereas restenotic lesions are composed of smooth muscle cells corresponding to injury caused by preceding balloon inflations. It is not known whether the different composition affects results of treatment by laser. In a clinical multicenter study, a mid-infrared, solid-state, pulsed-wave laser (holmium:YAG, 2.1 microns wavelength, 250-600 mJ/pulse, 5 Hz) was applied for revascularization of de novo and restenosis coronary lesions. Analysis of data was undertaken to document laser success, complications, and restenosis rate and to define whether the type of lesion treated had an effect on laser success and related complications. A total of 1340 patients with 1465 stenoses presented with symptomatic coronary artery disease. Laser success was 87 and 86% in these lesions, respectively. Overall procedural success of 93% was achieved. Restenosis lesions, known to be composed of smooth muscle proliferation, needed more laser energy for ablation than de novo lesions, which contain an atherosclerotic plaque (130 +/- 123 pulses vs 109 +/- 31, p = 0.001). Procedure-related Q-wave myocardial infarction was significantly higher in patients with de novo lesions over patients with restenosis lesions (1.4 vs 0.2%, p = 0.05). With the mid-infrared, pulsed-wave, holmium:YAG laser, the composition of the target lesion affects the energy level required, as well as the procedure-related complications.

The Role of the Perfusion Balloon Catheter After an Initially Unsuccessful Coronary Intervention

Major dissection and acute closure following conventional percutaneous transluminal coronary angioplasty (PTCA) occur in 5%-10% of cases and lead to significant morbidity. Newer percutaneous modalities such as directional coronary atherectomy (DCA), excimer laser coronary angioplasty (ELCA), rotational ablation, and transluminal extraction atherectomy (TEC) can also be complicated by dissection and acute closure. Redilatation with conventional balloon catheters can reestablish patency of the artery or improve flow in a minority of cases. The perfusion balloon catheter (PBC) has several advantages over conventional balloon angioplasty in this situation. In approximately 70% of these cases, subsequent use of a PBC yields an acceptable clinical and angiographic result. The PBC permits rapid resolution of ischemia caused by acute closure or a flow-limiting dissection. New modifications of the PBC make it possible to position the catheter in nearly all segments of the coronary arterial tree including locations not accessible to other modalities, such as coronary stents or DCA, that are also used for salvage after a failed coronary intervention. Even if the PBC does not yield a definitive result, it allows rapid restoration of antegrade flow prior to coronary artery bypass grafting or coronary stent placement. Because of its ease of use, wide applicability, and efficacy, the PBC should be considered as the initial means of treatment in cases of major dissection or acute closure following any modality of percutaneous coronary revascularization.

Predictors of restenosis after excimer laser coronary angioplasty

One hundred twenty-five lesions successfully treated with excimer laser coronary angioplasty at 3 centers were analyzed in a central core laboratory using detailed quantitative angiographic analysis. Sixty-seven narrowings had restenosis (≥50% diameter stenosis at restudy). Correlates of restenosis were as follows: baseline diameter stenosis was 79% in the restenosis group versus 71% in the group without restenosis (p = 0.0002), baseline minimal diameter stenosis was 0.55 mm in the restenosis group versus 0.72 mm in the group without restenosis (p = 0.006), final diameter stenosis was 40% in the restenosis group versus 32% in the group without restenosis (p = 0.002), lesion length ≥7 mm was present in 43% of the restenosis group versus 21% in the group without restenosis (p = 0.009), and Thrombolysis in Myocardial Infarction trial flow 0 to 2 was 33% in the restenosis group versus 15% in the group without restenosis (p = 0.025). The strongest multivariate correlate of restenosis was the baseline diameter stenosis (p = 0.003). Whereas most predictors were not controllable, achieving a low residual diameter stenosis that is operator-dependent can favorably influence the restenosis rate.

782-2 Longterm Outcome of Excimer Laser Angioplasty Versus Balloon Angioplasty in Functional and Total Coronary Occlusions

From September 1991 until November 1993 we randomized 103 patients with functional and total coronary occlusions to Excimer Laser Coronary Angioplasty (ELCA, n = 49) or Balloon Angioplasty (BA, n = 54) as part of a multi-center trial (AMRO) comparing ELCA versus BA in type B or C-Iesions. We report on the longterm clinical and angiographic outcome of this subgroup. Procedural success (PS) was defined as &lt; 50% residual stenosis at the end of the procedure. Clinical endpoints were: death (D), myocardial infarction (MI), coronary bypass surgery (CABG) or repeat angioplasty (re-PTCA) of the randomized segment within 6 months follow-up. Angiographic endpoint was the net gain (NG) in minimal lumen diameter at six months follow-up relative to the pre-procedural baseline determined by a computer-assisted automated edge detection algorithm (CAAS II). Functional status (FS) at six months was graded according to the Canadian Cardiovascular Society classification. Baseline patient characteristics were similar in both groups. ELCA was followed by BA in all patients. Re-occlusion of the treated segment during 6 months follow-up was 33% in the ELCA group versus 23% in the BA group (not significant).Empty CellnPS(%)D/MI/CAB/re-PTCANG ± SDFS(0-IV)ELCA49650/1/4/100.7 ± 0.729/6/10/4/0BA54610/3/2/80.7 ± 0.727/5/12/8/2 None of the comparisons were significantly different. Excimer Laser Angioplasty compared to Balloon Angioplasty in functional and total coronary occlusion yields similar results with respect to longterm clinical and angiographic outcome.

946-104 The Evolving Utility of Intracoronary Ultrasound

Although the use of intracoronary ultrasound (ICUS) imaging before and/or after the specific intervention has been reported by many investigators, its utility for altering interventional decision making has not been fully assessed. Eighty four successive cases of ICUS were divided into 2 time periods and studied as to how frequently the ICUS affected the coronary interventional strategy. A 3.5 F, 30 MHz (Boston Scientific) catheter with a HP Intravascular Imaging System was used. An ICUS image that led to a decision not provided by angiographic finding was considered as having changed interventional strategy. Frequency of interventional decision making based on ICUS significantly increased from 48.5% in early series (2/93–10/93) to 84.3% in recent series (11/93–8/94) (p = 00006). ICUS imagings were considered significantly more useful for decision making in stent cases (85.7%) and in directional coronary atherectomy (DCA) or excimer laser coronary angioplasty (ELCA) cases (81.3%) than in PTCA cases (51.5%) (p = 0.0023). Between the 2 periods, there were changes in the indications for ICUS. Post-stenting imaging significantly increased from 15.2% (5/33) to 41.2% (21/51) (p = 0.0154), and post-PTCA imaging significantly decreased from 60.6% (20/33) to 27.5% (14/51) (p = 0.0033). Peri-ELCA or peri-DCA imaging increased from 12.1% (4/33) to 32.4% (16/511 and the imaging of angiographically ambiguous lesions including ostial segments increased from 24.2% (8/33) to 41.1% (22/51) (p = 0.0011). The frequency of decision making based on ICUS findings has increased dramatically in association with a pre-selection of patients having stents, DCA or ELCA, and angiographically ambiguous lesions, indicating that ICUS imaging has changed from being predominantly an investigative tool to a method for supporting clinical decision making.