Application of excimer laser angioplasty in acute myocardial infarction

Benefits of excimer laser coronary angioplasty over thrombus aspiration therapy for patients with acute coronary syndrome and thrombolysis in myocardial infarction flow grade 0

In primary percutaneous coronary intervention (PCI) for acute coronary syndrome (ACS), the presence of a thrombus or unstable plaque can cause microvascular obstructions, which may increase infarct size and reduce survival. Excimer laser coronary angioplasty (ELCA) is a unique revascularization technique that can vaporize plaques and thrombi. However, to date, only few reports indicate the efficacy of ELCA for ACS. We retrospectively analyzed 113 consecutive ACS patients who underwent PCI with either ELCA or manual thrombus aspiration therapy (TA) before balloon angioplasty or stenting and who had a Thrombolysis in Myocardial Infarction flow (TIMI) grade 0 on the first contrast injection within 24 h of onset at our hospital from March 2011 to March 2020. Patients were divided into two groups by the procedure used: ELCA (N = 48) and TA (N = 50). Door-to-reperfusion time was significantly shorter in the ELCA group than TA group (89.2 ± 6.7 vs. 137.9 ± 12.3 min, respectively; P < 0.01). There was also a significant difference in peak creatine kinase-myocardial band between the ELCA and TA groups (242 ± 25 vs. 384 ± 63 IU/L, respectively; P = 0.04). Although there was no difference in myocardial blush grade (MBG) before treatment, the MBG after treatment was higher in the ELCA group (P < 0.01). In-hospital major adverse cardiac events (MACE) were also significantly fewer in the ELCA group than in the TA group (8% vs. 20%, P = 0.045). ELCA for TIMI grade 0 ACS may shorten reperfusion time, improve the MBG score, and reduce MACE when compared to TA.

Comparison of 0.9-mm and 1.4-mm catheters in excimer laser coronary angioplasty for acute myocardial infarction

Excimer laser coronary angioplasty (ELCA) is a unique revascularization modality that can vaporize plaque and thrombus. Compared to thrombus aspiration therapy, ELCA is reported to provide better microcirculation and reduced peripheral embolism in treatment for acute coronary syndrome. Excimer laser catheters come in various sizes, and we sought to compare the 0.9- and 1.4-mm-diameter catheters. We retrospectively enrolled 90 acute myocardial infarction (AMI) patients who underwent primary percutaneous coronary intervention with excimer laser from August 2013 to March 2017 in our hospital. Patients were grouped by diameter of catheter that had been used, the 0.9 mm group (n = 51) and 1.4 mm group (n = 39). We evaluated myocardial perfusion, procedural success rate, short-term outcome, lesion crossability, and complications between the two groups. The percentage of patients whose final thrombolysis in myocardial infarction (TIMI) grade was 3 (0.9 mm 86.3% vs 1.4 mm 89.7% p = 0.75) and final myocardial blush grade (MBG) was 3 (0.9 mm 72.5% vs 1.4 mm 69.2% p = 0.82) was similarly high for both groups. Procedural success rate, in-hospital major adverse cardiac events (MACE), lesion crossability, and complications were also similar. This study showed that efficacy of 0.9 and 1.4 mm excimer laser catheter was equivalent in ELCA for AMI patients. If one takes into account lesion crossability, debulking effects, and the stunned platelets phenomenon, the 0.9 mm excimer laser catheter is sufficient for ELCA in AMI patients.

The Effect of Interventional Treatment in Acute Myocardial Infarction on ST Resolution: A Comparison of Coronary Angioplasty with Excimer Laser Angioplasty

The treatment methods for acute myocardial infarction (MI) have started to change in the new millennium. Myocardial perfusion (ST-segment resolution) is the target rather than achieving TIMI-III flow in the infarct-related artery. In this study the authors compared the effect of percutaneous transluminal coronary angioplasty (PTCA) and excimer laser angioplasty (ELCA), which was accepted as one of the thrombolysis methods, on ST-segment resolution. A stent was applied after ELCA to 36 patients (4 women, 32 men; mean age 50.44 ±9.8 years) in group I and a stent was applied after balloon angioplasty to 44 patients (5 women, 39 men; mean age 50.77 ±12.2 years) in group II. Fisher’s exact test was used in the analysis of data, and p<0.05 was accepted as significant. There was no difference between the groups with respect to symptom duration, time to angioplasty, risk factors, infarct localization, stent diameter, and length. TIMI-III flow was achieved in 33 patients (92%) in group I and in 40 patients (91%) in group II. There was no statistical difference in TIMI flow between the groups. In group I, complete ST resolution was observed in 75% (27/36) of the patients, partial resolution in 22% (8/36), and resolution was unsuccessful in 3% (1/36). In group II, complete, partial, and unsuccessful ST resolution were 41% (18/44), 45% (20/44), and 14% (6/44), respectively. The mean ST resolution was 82.78 ±11.8% in group I and 66.36 ±10% in group II (p=0.001). ST segment resolution, which is a good predictor of tissue perfusion, was higher with ELCA than with balloon angioplasty. These findings should be supported by large randomized studies.

Use of Excimer Laser for Thrombus Containing Lesion

The presence of thrombus in the lesion before balloon angioplasty increases the complications arising from mechanical intervention. It is known that the use of Gp llb/llla receptor blockers before the intervention enhances the reliability of the procedure. Laser thrombolysis was applied to a patient who underwent coronary angiography due to recurrent chest pain after thirty six hour administration of tirofiban and who was found to have a thrombus so large as to block the distal vessel bed of the right coronary artery. Following the procedure, the entire thrombus was broken down and Grade III distal myocardial perfusion was achieved. This case is important in demonstrating that laser application is a viable alternative in such instances, especially considering that intervention in acute coronary syndromes is on the increase and cardiologists will frequently encounter such cases.

Excimer Laser Coronary Angioplasty in Acute Myocardial Infarction

We evaluated the short-term results of percutaneous excimer laser angioplasty in acute myocardial infarction. Of the 18 patients studied, 2 were female and 16 male with a mean age of 56.6 ± 12.1 years. Thrombolysis in myocardial infarction grades 0, 1, and 2 flow was observed in 10, 5, and 3 cases, respectively, prior to the procedure. The degree of stenosis was 97.9% ± 5.1%. The lesion was crossed with a laser catheter in all cases, using a mean number of 808 ± 384 laser pulses. Type C dissection developed in only 1 case (6%). Except for this case, distal flow was grade 3 in all the patients. Following the procedure, ST segment resolution exceeding 70% was achieved in 14 cases (78%) within the first 90 minutes. The success rate of laser ablation was 94% (17 patients). Stent implantation was performed in all the cases. In conclusion, laser angioplasty is an effective and reliable treatment for acute myocardial infarction.

Treatment of subacute and chronic thrombotic occlusions of lower extremity peripheral arteries with the excimer laser: a feasibility study

BACKGROUND

Thrombus is highly prevalent in patients with recent symptoms (< 6 months) of claudication or limb ischemia due to an occluded culprit lower extremity vessels. Treatment of these thrombotic occlusions is challenging. In this feasibility study, the excimer laser (Spectranetics, Colorado Springs, CO) has been tested for its safety and ability to ablate thrombus in patients with recent arterial occlusions.

METHODS

Angiographic operator assessment and volumetric core lab quantitation of the thrombus were performed at baseline and after excimer laser but prior to definitive treatment of the vessel to evaluate thrombus resolution. Consecutive patients were prospectively enrolled at a single site. Procedural success was defined as achieving a residual stenosis of <30% after final treatment with no intraprocedural complications requiring additional treatment.

RESULTS

20 consecutive patients were enrolled in this study (8 males, mean age 69.5±11.1 years). Based on patients symptom onset, 12 patients were subacute (> 24 h, < 30 days), and 8 chronic (between 1 to 6 months). 15/20 (75%) had restenotic occlusions. Due to the long, occlusive nature of these lesions, only 8 patients had complete intravascular ultrasound images at each time point which allowed volumetric analysis by the core lab. There was no statistical difference in plaque/thrombus volume between baseline (pretreatment) and excimer laser (P=.68). There was however a significant reduction in residual angiographic stenosis post laser alone (100% vs. 66.75%±23.9%, P=.001). Procedural success was 100%. There were no deaths or amputations. Bail out stenting was performed in 10/20 (50%) patients. Embolic filters were used in 15/20 (75%) of patients. Macrodebris>2 mm were seen in 85.7% of filters. There was no in-hospital or 30-day reocclusion of the treated vessel but one patient had a vascular access complication (small AV fistula) conservatively managed. No other serious adverse events were noted.

CONCLUSION

Using the excimer laser appears safe in this small feasibility study of subacute and chronic thrombotic occlusions. Angiographically, there was a significant reduction in percent stenosis with the laser alone. The limited IVUS data did not show a reduction in plaque/thrombus volume but the number of interpretable ultrasounds was small. Further data are needed to address the effectiveness of the laser in treating these thrombotic occlusions and its advantages over balloon angioplasty.

Excimer laser in myocardial infarction: a comparison between STEMI patients with established Q-wave versus patients with non-STEMI (non-Q)

Patients sustaining acute myocardial infarction (AMI) often require urgent percutaneous revascularization within the first 24 h from onset of the infarction due to continuous ischemia and hemodynamic instability. Upon arrival to the cardiac catheterization, the electrocardiogram of AMI patients may exhibit acute ST-elevation (STEMI) with or without accompanying Q-wave or depression of the ST segment (non-STEMI or non-Q-wave infarction). Data comparing acute outcome of device application in patients presenting for urgent revascularization with established Q-wave myocardial infarction (QWMI) versus those with non-STEMI (NQMI) are sparse. Excimer laser is a revascularization modality applied for debulking of atherosclerotic plaque and vaporization of associated thrombus in the setting of AMI. One hundred fifty-one AMI patients with continuous chest pain and ischemia who enrolled into a multicenter study and underwent urgent revascularization were divided for the purpose of a retrospective analysis into two groups. One group presented with established electrocardiographic Q-wave, whereas the other had ST-depression (NQMI). In comparison with the NQMI group, the QWMI patients had a higher incidence of failed thrombolytic therapy (17% vs 3, p = 0.006), cardiogenic shock (20 vs 6%, p = 0.01), left anterior descending as a culprit infarct-related vessel (46 vs 14%, p < 0.0001), a higher incidence of TIMI 0 flow (48 vs 24%, p = 0.04), a heavier thrombus burden (grade 4 TIMI thrombus, 58 vs 23%; p = 0.0001), and higher CPK (1272 +/- 2180 vs 404 +/- 577, p = 0.001) and troponin levels (62 +/- 95 vs 14 +/- 48, p = 0.0003). Both groups underwent laser angioplasty and stenting for relief of continuous chest pain and ischemia within 24 h of infarction onset. Quantitative coronary arteriography in an independent core laboratory measured similar improvement in baseline minimal luminal diameter and percent diameter stenosis by application of laser energy in both groups. Among the QWMI patients, a significantly higher acute gain was recorded with the laser treatment in lesions containing a large/extensive thrombus burden as compared with lesions containing only a small clot burden (1.2 +/- 0.7 vs 0.8 +/- 0.5, p = 0.01). Such a phenomenon was not detected among the NQMI patients (1.0 +/- 0.5 vs 0.8 +/- 0.6, p=ns). Baseline TIMI flow grade (0.9 +/- 1.0 for QWMI vs 1.5 +/- 1.2 for NQMI, p = 0.0001) increased with laser emission to 2.8 +/- 0.5 and subsequently reached a final level of TIMI 3 in both groups. In comparison with the QWMI patients, there was a trend toward a reduced rate of major adverse coronary events among the NQMI patients (12% QWMI vs 4% NQMI, p = 0.09). Significant differences in baseline clinical characteristics, extent of myocardial damage, location of infarct related vessel, thrombus burden, and TIMI flow exist between QWMI and NQMI patients who require urgent intervention. However, application of excimer laser results in similar high procedural success and low complication rates in both groups. Maximal acute laser gain is achieved among QWMI patients whose lesions are laden with a heavy thrombus burden.

Excimer laser thrombus elimination for prevention of distal embolization and no-reflow in patients with acute ST elevation myocardial infarction

BACKGROUND

Results for standard revascularization therapies in acute myocardial infarction (AMI) have been limited in part by distal embolization, a process which might be reduced by the application of ultraviolet laser light. The aim was to assess feasibility and safety of excimer laser coronary angioplasty (ELCA) in a randomized study in AMI.

METHODS

Twenty-seven consecutive patients with ST-segment elevation AMI (aged 57.8+/-9.2 years) were randomized either to balloon angioplasty and stent implantation alone (n=13) or adjunct ELCA (n=14). Quantitative coronary angiography was analyzed by an independent core laboratory.

RESULTS

ELCA was feasible and safe in all cases. No procedure-associated complications were observed. Similar results were found for main parameters in laser (L) and control (C) patients: diameter stenosis decreased from 94.3+/-9.6 to 20.7+/-10.3% (L) and from 82.7+/-16.8 to 18.9+/-5.5% (C) (p=ns; L vs. C). TIMI flow increased from 0.7+/-1.2 to 2.8+/-0.4 and from 1.7+/-1.5 to 3.0+/-0 (p=ns; L vs. C), respectively. The post-procedural myocardial blush score did not differ between the groups (2.1+/-1.3 and 2.7+/-1.0; p=ns; L vs. C) and the final corrected TIMI frame count (cTFC) was also similar in both groups (23+/-7 and 22+/-4; p=ns; L vs. C), but the cTFC gain was higher in the laser group (53+/-14% and 35+/-20%; p<0.05; L vs. C).

CONCLUSIONS

Laser angioplasty is feasible and safe for the treatment of patients with ST elevation AMI. Procedural results were at least on par with conventional treatment. Further randomized controlled trials are needed to assess the benefit of laser angioplasty in AMI.

Mechanical thrombectomy options in complex percutaneous coronary interventions

Percutaneous coronary interventions (PCI) of thrombus-containing lesions are associated with an increased risk of acute complications and poorer long term vessel patency. Dealing with these vessels provides many technical challenges, especially with the significant risk of coronary no reflow and distal embolization. Pharmacological strategies, including intravenous and intracoronary glycoprotein IIbIIIa inhibitors reduce intracoronary thrombus propagation, improve TIMI flow and are associated with a reduction in adverse event rates. Mechanical strategies (particularly embolic protection and thrombectomy catheters) help to improve coronary blood flow and myocardial perfusion. However, their impact on clinical outcomes is less clear. The use of embolic protection devices is associated with better perfusion, blood flow, and clinical outcomes among patients undergoing saphenous vein graft (SVG) PCI. However, the role for these devices in primary PCI and native coronary artery interventions is uncertain. This study examines the current approaches to manage thrombotic lesions during PCI and reviews the evidence in support of the different mechanical thrombectomy options that are available to the interventional cardiologist.

Excimer laser angioplasty in acute myocardial infarction (the CARMEL multicenter trial)

Patients with acute myocardial infarction (AMI) with thrombus-laden lesions constitute a revascularization challenge. Thrombus and atherosclerotic plaque absorb laser energy; thus, we studied the safety and efficacy of excimer laser in AMI. In a multicenter trial, 151 patients with AMI underwent excimer laser angioplasty. Baseline left ventricular ejection fraction was 44 +/- 13%, and 13% of patients were in cardiogenic shock. A saphenous vein graft was the target vessel in 21%. Quantitative coronary angiography and statistical analysis were performed by independent core laboratories. A 95% device success, 97% angiographic success, and 91% overall procedural success rate were recorded. Maximal laser gain was achieved in lesions with extensive thrombus burden (p <0.03 vs small burden). Thrombolysis In Myocardial Infarction (TIMI) trial flow increased significantly by laser: 1.2 +/- 1.1 to 2.8 +/- 0.5 (p <0.001), reaching a final 3.0 +/- 0.2 (p <0.001 vs baseline). Minimal luminal diameter increased by laser from 0.5 +/- 0.5 to 1.6 +/- 0.5 mm (mean +/- SD, p <0.001), followed by 2.7 +/- 0.6 mm after stenting (p <0.001 vs baseline and vs after laser). Laser decreased target stenosis from 83 +/- 17% to 52 +/- 15% (mean +/- SD, p <0.001 vs baseline), followed by 20 +/- 16% after stenting (p <0.001 vs baseline and vs after laser). Six patients (4%) died, each presented with cardiogenic shock. Complications included perforation (0.6%), dissection (5% major, 3% minor), acute closure (0.6%), distal embolization (2%), and bleeding (3%). In a multivariant regression model, absence of cardiogenic shock was a significant factor affecting procedural success. Thus, in the setting of AMI, gaining maximal thrombus dissolution in lesions with extensive thrombus burden, combined with a considerable increase in minimal luminal diameter and restoration of anterograde TIMI flow, support successful debulking by excimer laser. The presence of thrombus does not adversely affect procedural success; however, cardiogenic shock remains a predictor of major adverse events during hospitalization.

Prevention of distal embolization and no-reflow in patients with acute myocardial infarction and total occlusion in the infarct-related vessel: A subgroup analysis of the cohort of acute revascularization in myocardial infarction with excimer laser?CARMEL multicenter study

To overcome the adverse complications of percutaneous coronary interventions in thrombus laden lesions (i.e., distal embolization, platelet activation, no-reflow phenomenon), mechanical removal of the thrombus or distal embolization protection devices are frequently required. Pulsed-wave ultraviolet excimer laser light at 308 nm can vaporize thrombus, suppress platelet aggregation, and, unlike other thrombectomy devices, ablate the underlying plaque. The following multicenter registry was instituted to evaluate the safety and efficacy of laser ablation in patients presenting with acute myocardial infarction (AMI) complicated by persistent thrombotic occlusions. Patients with AMI and complete thrombotic occlusion of the infarct-related vessel were included in eight participating centers. Patients with further compromising conditions (i.e., cardiogenic shock, thrombolysis failures) were also included. Primary endpoint was procedural respective laser success; secondary combined endpoints were TIMI flow and % stenosis by quantitative coronary analysis and visual assessment at 1-month follow-up. Eighty-four percent of all patients enrolled (n = 56) had a very large thrombus burden (TIMI thrombus scale > or = 3), and 49% were compromised by complex clinical presentation, i.e., cardiogenic shock (21%), degenerated saphenous vein grafts (26%), or thrombolysis failures (5%). Laser success was achieved in 89%, angiographic success in 93%, and the overall procedural success rate was 86%. The angiographic prelaser total occlusion was reduced angiographically to 58% +/- 25% after laser treatment and to 4% +/- 13% final residual stenosis after adjunctive balloon angioplasty and/or stent placement. TIMI flow increased significantly from grade 0 to 2.7 +/- 0.5 following laser ablation (P < 0.001) and 3.0 +/- 0.2 upon completion of the angioplasty procedure (P > 0.001 vs. baseline). Distal embolizations occurred in 4%, no-reflow was observed in 2%, and perforations in 0.6% of cases. Laser-associated major dissections occurred in 4% of cases, and total MACE was 13%. The safety and efficacy of excimer laser for thrombus dissolution in a cohort of high-risk patients presenting with AMI and total thrombotic occlusion in the infarct-related vessel are encouraging and should lead to further investigation.

Excimer laser ablation for valvular angioplasty in pulmonary atresia and intact ventricular septum

BACKGROUND AND OBJECTIVES

The prognosis for infants with pulmonary atresia and intact ventricular septum (PA/IVS) is poor and they present a major management challenge. Mechanical penetration of the atretic pulmonary valve is an applicable option for decompression of the right ventricle and optimization of left ventricular function. The utilization of laser energy for debulking and vaporization of the atretic valve tissue is a relevant approach due to the potential for controlled, precise mode of energy distribution.

STUDY DESIGN/PATIENTS AND METHODS

A 4-month-old female with PA/IVS whose failure to thrive was accompanied by critical hemodynamic abnormalities received successful percutaneous pulmonary valve plate ablation by a 0.9 mm pulsed-wave ultraviolet excimer laser catheter (308 nm wavelength, fluence 50 mJ/mm(2); 30 Hz). A "step-by-step" lasing technique was applied whereby the tip of the emitting laser catheter is advanced ahead of a guide wire that serves mainly as support for positioning of that catheter.

RESULTS

Adequate penetration of the atretic tissue enabled introduction of balloon dilations resulting in patency of the atretic valve, decompression of the right ventricle, improved right and left ventricular hemodynamics, and oxygenation. To further investigate the effect of excimer laser energy on atretic valvular tissue this laser was applied in a specimen of heart from an infant who died because of PA/IVS. Histopathologic examination of the irradiated tissue revealed no laser-induced injury to the pulmonary valve.

CONCLUSIONS

Thus, laser ablation and penetration of an atretic pulmonary valve is feasible and safe. The penetration of the atretic valve with the laser catheter enables subsequent introduction of various sizes balloon dilations. The application of available laser sources for treatment of congenital heart diseases is reviewed.

Power thrombectomy in acute ischemic coronary syndromes

Intracoronary thrombi are commonly found in patients with acute coronary syndromes. A large thrombus burden or a platelet-rich thrombus frequently resists pharmacologic therapy ("thrombolytic ceiling"). In such cases restoration of adequate antegrade coronary flow necessitates application of a mechanical force. Power thrombectomy is a revascularization strategy incorporating a mechanical device for removal of occlusive coronary thrombi in conjunction with or following administration of either platelet glycoprotein IIb/IIIa receptor inhibitors or thrombolytic agents, or both. Mechanical devices for power thrombectomy include ultrasound sonication, rheolytic thrombectomy (Angiojet), laser, transluminal extraction catheter, aspiration catheter, and to a limited extent, balloon angioplasty. In acute coronary syndromes the strategy of power thrombectomy aims to achieve the clinical advantages of more nearly complete vessel patency, improved antegrade flow, and enhanced preservation of myocardial tissue.

Comparison of effectiveness of excimer laser angioplasty in patients with acute coronary syndromes in those with versus those without normal left ventricular function

Depressed left ventricular (LV) ejection fraction (EF) adversely affects procedural outcome during percutaneous coronary revascularization. This study examined the acute results, effectiveness, and safety of excimer laser coronary angioplasty (ELCA) in patients with acute coronary ischemic syndromes whose LVEF was depressed (<40%) versus those with preserved LVEF. One hundred patients with acute coronary syndromes (51 with unstable angina and 49 with acute myocardial infarction) underwent ELCA. Twenty-five patients (group 1) (29 lesions; 72% thrombotic) had decreased LVEF (mean 28 +/- 6%) and 75 patients (group 2) (81 lesions; 60% thrombotic) had preserved LVEF (mean 53 +/- 8%). Group 1 had a higher incidence of 3-vessel disease, Q-wave acute myocardial infarction, cardiogenic shock, diabetes, and hypertension. High laser success (87% group 1 vs 93% group 2, p = NS) and procedural success (93% group 1 vs 98% group 2, p = NS) were achieved in both groups. Minimal luminal diameter in group 1 increased from 0.7 +/- 0.5 to 1.4 +/- 0.5 mm after the laser procedure and finally to 3.0 +/- 0.4 mm; in group 2, minimal luminal diameter increased from 0.7 +/- 0.4 to 1.3 +/- 0.5 mm after the procedure to a final of 3.0 +/- 0.5 mm. The laser energy vaporized 75% of thrombus burden from the target lesion in group 1 versus 79% in group 2 (p = NS). Thrombolysis In Myocardial Infarction flow in group 1 increased from 1.4 +/- 1.2 to 2.7 +/- 0.7 by laser and finally to 2.9 +/- 0.3, and in group 2 from 2.0 +/- 1.0 to 2.8 +/- 0.6 after the laser procedure to a final of 2.9 +/- 0.4. There were no deaths, emergency bypass surgeries, strokes, or acute vessel closures in either group. Thus, ELCA is a safe and feasible revascularization modality for patients with acute coronary syndromes whose LVEF is depressed. The laser energy vaporizes a large thrombus burden from the treated plaque. Angiographic intracoronary thrombus does not adversely affect device and procedural success in these select patients.