Percutaneous Myocardial Laser Revascularization Research Articles

Design of clinical intelligent percutaneous myocardial laser revascularization operating platform software

Percutaneous transmyocardial laser revasculariztion (PMLR), a kind of new percutaneous coronary intervention based on transmyocardial laser revascularization (TMLR) is to improve the circulation of ischemia myocardium by laser myocardial revascularization from the cardiac cavity. In our previous research, the characteristic of laser transmission in myocardium including photon reflection, absorption and scattering was introduced. The photon state at the emission, transmission and disappearance stage, the processes of photon weight decay and the change of photon movement step and direction were described and simulated by using Monte Carlo method. All of the above were simulated by MATLAB, and the relationship between different optical property parameters, absorption coefficient, scattering coefficient, anisotropic coefficient, and photon energy density in myocardium was discussed. In this study simulation of photon transport using Monte Carlo operating platform was programmed by C++ language to investigate the influence of increasing photons on the simulation at different optical properties parameters and clinical intelligent PMLR operating platform was established to achieve the optimal number of laser holes, aperture, single hole perfusion, threshold power and corresponding parameters of each hole, which provided a reference for the operation program.

Effectiveness of percutaneous laser revascularization therapy for refractory angina.

Refractory angina is a debilitating disease characterized by persistent cardiac pain resistant to all conventional treatments for coronary artery disease. Percutaneous myocardial laser revascularization (PMLR) has been proposed to improve symptoms in these patients. We used meta-analysis to assess the effectiveness of PMLR versus optimal medical therapy for improving angina symptoms, health-related quality of life (HRQL), and exercise performance; the impact on all-cause mortality was also examined. Seven trials, involving a total of 1,213 participants were included. Our primary analyses showed that at 12-month follow-up, those who had received PMLR had ≥2 Canadian Cardiovascular Society class angina symptom reductions, OR 2.13 (95% CI, 1.22 to 3.73), as well as improvements in aspects of HRQL including angina frequency, SMD = 0.29 (95% CI, 0.05 to 0.52), disease perception, SMD = 0.37 (95% CI, 0.14 to 0.61), and physical limitations, SMD = 0.29 (95% CI, 0.05 to 0.53). PMLR had no significant impact on all-cause mortality. Our secondary analyses, in which we considered data from one trial that featured a higher-dose laser group, yielded no significant overall impact of PMLR across outcomes. While PMLR may be effective for improving angina symptoms and related burden, further work is needed to clarify appropriate dose and impact on disease-specific mortality and adverse cardiac events.

Spinal cord stimulation in the treatment of refractory angina: systematic review and meta-analysis of randomised controlled trials

BackgroundThe aim of this paper was undertake a systematic review and meta-analysis of the use of spinal cord stimulation (SCS) in the management of refractory angina.MethodsWe searched a number of electronic databases including Medline, Embase and Cochrane Library up to February 2008 to identify randomised controlled trials (RCTs) reporting exercise capacity, ischemic burden, functional class, quality of life, usage of anti-anginal medication, costs and adverse events including mortality. Results were reported both descriptively for each study and using random effects meta-analysis. Given the variety in outcomes reported, some outcome results were pooled as standardised mean differences (SMD) and reported in standard deviation units.ResultsSeven RCTs were identified in a total of 270 refractory angina patients. The outcomes of SCS were found to be similar when directly compared to coronary artery bypass grafting (CABG) and percutaneous myocardial laser revascularisation (PMR). Compared to a 'no stimulation' control, there was some evidence of improvement in all outcomes following SCS implantation with significant gains observed in pooled exercise capacity (SMD: 0.76, 0.07 to 1.46, p = 0.03) and health-related quality of life (SMD: 0.83, 95% CI: 0.32 to 1.34, p = 0.001). Trials were small and were judged to range considerably in their quality. The healthcare costs of SCS appeared to be lower than CABG at 2-years follow up.ConclusionSCS appears to be an effective and safe treatment option in the management of refractory angina patients and of similar efficacy and safety to PMR, a potential alternative treatment. Further high quality RCT and cost effectiveness evidence is needed before SCS can be accepted as a routine treatment for refractory angina.

Clinical and cost-effectiveness analysis of an open label, single-centre, randomised trial of spinal cord stimulation (SCS) versus percutaneous myocardial laser revascularisation (PMR) in patients with refractory angina pectoris: The SPiRiT trial

BackgroundPatients with refractory angina have significant morbidity. This study aimed to compare two of the treatment options, Spinal Cord Stimulation (SCS) and Percutaneous Myocardial Laser Revascularisation (PMR) in terms of clinical outcomes and cost-effectiveness.MethodsEligible patients were randomised to PMR or SCS and followed up for exercise tolerance time (ETT), Canadian Cardiovascular Society (CCS) classification and the quality of life measures SF-36, Seattle Angina Questionnaire and the EuroQoL at 3, 12 and 24 months. Utilities were calculated using the EQ-5D and these and costs were compared between groups. The incremental cost-effectiveness ratio (ICER) per QALY for SCS compared to PMR was also calculated.ResultsAt 24 months post-randomisation, patients that had SCS and PMR had similar ETT (mean difference 0.05, 95% CI -2.08, 2.18, p = 0.96) and there was no difference in CCS classification or quality of life outcomes. The difference in overall mean costs when comparing SCS to PMR was GBP5,520 (95% CI GBP1,966 to GBP8,613; p < 0.01) and the ICER of using SCS was GBP46,000 per QALY.ConclusionOutcomes after SCS did not differ appreciably from those after PMR, with the former procedure being less cost-effective as currently applied. Larger studies could clarify which patients would most benefit from SCS, potentially increasing cost-effectiveness.Trial registrationCurrent Controlled Trials ISRCTN09648950

A study to assess changes in myocardial perfusion after treatment with spinal cord stimulation and percutaneous myocardial laser revascularisation; data from a randomised trial

BackgroundSpinal cord stimulation (SCS) and percutaneous myocardial laser revascularisation (PMR) are treatment modalities used to treat refractory angina pectoris, with the major aim of such treatment being the relief of disabling symptoms. This study compared the change in myocardial perfusion following SCS and PMR treatment.MethodsSubjects with Canadian Cardiovascular Society class 3/4 angina and reversible perfusion defects as assessed by single-photon emission computed tomographic myocardial perfusion scintigraphy were randomised to SCS (34) or PMR (34). 28 subjects in each group underwent repeat myocardial perfusion imaging 12 months post intervention. Visual scoring of perfusion images was performed using a 20-segment model and a scale of 0 to 4.ResultsThe mean (standard deviation) baseline summed rest score (SRS) and stress scores (SSS) were 4.6 (5.7) and 13.6 (9.0) in the PMR group and 6.1 (7.4) and 16.8 (11.6) in the SCS group. At 12 months, SRS was 5.5 (6.0) and SSS 15.3 (11.3) in the PMR group and 6.9 (8.2) and 15.1 (10.9) in the SCS group. There was no significant difference between the two treatment groups adjusted for baseline (p = 1.0 for SRS, p = 0.29 for SSS).ConclusionThere was no significant difference in myocardial perfusion one year post treatment with SCS or PMR.

An open label, single-centre, randomized trial of spinal cord stimulation vs. percutaneous myocardial laser revascularization in patients with refractory angina pectoris: the SPiRiT trial: reply

An open label, single-centre, randomized trial of spinal cord stimulation vs. percutaneous myocardial laser revascularization in patients with refractory angina pectoris: the SPiRiT trial: reply

An open label, single-centre, randomized trial of spinal cord stimulation vs. percutaneous myocardial laser revascularization in patients with refractory angina pectoris: the SPiRiT trial

McNab et al. 1 are to be congratulated to have performed the first randomized controlled trial (RCT) to compare percutaneous myocardial laser revascularization (PMR) with spinal cord stimulation (SCS). The results are encouraging and confirm previous results on both therapy modalities. In the introduction, they have mentioned the many techniques for patients with refractory angina. They have stated that there is little evidence directly comparing these multiple therapeutic modalities, not mentioning the RCT performed by …

An open label, single-centre, randomized trial of spinal cord stimulation vs. percutaneous myocardial laser revascularization in patients with refractory angina pectoris: the SPiRiT trial

Refractory angina pectoris leads to significant morbidity. Treatment options include percutaneous myocardial laser revascularization (PMR) and spinal cord stimulation (SCS). This study was designed to compare these two treatments. Subjects with Canadian Cardiovascular Society (CCS) class 3/4 angina and reversible perfusion defects were randomized to SCS (34) or PMR (34). The primary outcome was to compare exercise treadmill time on a modified Bruce protocol over 12 months. Thirty subjects in both groups completed 12-month follow-up. The mean total exercise time was 6.38 +/- 3.45 min in the SCS group and 7.41+/-3.68 min in the PMR group at baseline and 7.08 +/- 0.67 min in the SCS group and 7.12 +/-0.71 min in the PMR group at 12 months (95% confidence limits for the difference between the groups -1.02 to + 2.2 min, P = 0.466). There were no differences in angina-free exercise capacity, CCS class, and quality of life between treatments. SCS patients had more adverse events in the first 12 months, mainly angina or SCS system related (P = 0.001). There was little evidence of a difference in effectiveness between SCS and PMR in patients with refractory angina.

Percutaneous myocardial laser revascularisation may not be effective in severe angina

Percutaneous myocardial laser revascularisation may not be effective in severe angina

Trial-based cost-utility comparison of percutaneous myocardial laser revascularisation and continued medical therapy for treatment of refractory angina pectoris

This study examined from a health service perspective whether percutaneous myocardial laser revascularisation (PMR) plus standard medical management is cost-effective when compared with standard medical management alone in the treatment of refractory angina. This involved a cost-utility analysis using patient-specific data from a single-centre, randomised, controlled trial carried out in the United Kingdom. Of 73 patients diagnosed as having refractory angina and not suitable for conventional forms of revascularisation, 36 were randomised to PMR plus medical management and 37 to medical management alone. We collected costs to the health service of PMR and all secondary sector health care contacts and cardiac-related medication in the 12 months following randomisation. Patient utility, measured using the EuroQol EQ-5D questionnaire, was combined with 12-month survival data to generate quality-adjusted life years (QALYs). The mean 12-month cost per patient for PMR was 8,307 pounds, and that for medical management was 1,888 pounds, giving a cost difference of 6,410 pounds. The mean QALY difference favoured PMR at 0.126, giving an incremental cost per QALY of 50,873 pounds. The cost-effectiveness acceptability curve indicates that the probability of PMR being cost-effective over the first 12 months is quite low. Whilst a longer period of follow-up might indicate continued benefit from PMR, which would make the intervention economically more attractive, PMR could not be considered cost-effective based on 1-year follow-up data.

A Blinded, Randomized, Placebo-Controlled Trial of Percutaneous Laser Myocardial Revascularization to Improve Angina Symptoms in Patients With Severe Coronary Disease

This study was a randomized, patient- and evaluator-blinded, placebo-controlled trial in patients treated using percutaneous myocardial laser revascularization. Previous studies using similar therapies have been confounded by placebo bias. A total of 298 patients with severe angina were randomly assigned to receive low-dose or high-dose myocardial laser channels or no laser channels, blinded as a sham procedure. The primary end point was the change in exercise duration from baseline examination to six months. The incidence of 30-day death, stroke, myocardial infarction, coronary revascularization, or left ventricular perforation occurred in two patients in the placebo, eight patients in the low-dose, and four patients in the high-dose groups (p = 0.12); 30-day myocardial infarction incidence was higher in patients receiving either low-dose or high-dose laser (nine patients) compared with placebo (no patients, p = 0.03). At six months, there were no differences in the change in exercise duration between those receiving a sham (28.0 s, n = 100), low-dose laser (33.2 s, n = 98), or high-dose laser (28.0 s, n = 98, p = 0.94) procedure. There were also no differences in the proportion of patients improving to better than Canadian Cardiovascular Society class III angina symptoms at six months. The follow-up visual summed stress single-photon-emission computed tomography scores were not significantly different from baseline in any group and were no different between groups. The modest improvement in angina symptoms assessed by the Seattle Angina Questionnaire also was not statistically different among the arms. Treatment with percutaneous myocardial laser revascularization provides no benefit beyond that of a similar sham procedure in patients blinded to their treatment status.

Angiogenic therapy for coronary artery and peripheral arterial disease

Neovascularization in chronically ischemic adult cardiac and skeletal muscle results from the processes of angiogenesis, arteriogenesis and vasculogenesis. Therapeutic angiogenesis describes an emerging field of cardiovascular medicine whereby new blood vessels are induced to grow to supply oxygen and nutrients to cardiac or skeletal muscle rendered ischemic as a result of progressive atherosclerosis. Various techniques have been utilized to promote new blood vessel growth in the heart and extremities, including mechanical means such as surgical or percutaneous myocardial laser revascularization, angiogenic growth factor therapies involving members of the vascular endothelial growth factor and fibroblast growth factor families, and more recently, cellular-based therapies using stem cells known as endothelial progenitor cells or angioblasts. The following review discusses each of these treatment strategies in detail including both preclinical and clinical data for their use in peripheral arterial and coronary artery disease.

Usefulness and safety of percutaneous myocardial laser revascularization for refractory angina pectoris

This prospective, double-blind, randomized, sham-controlled trial was designed to control for patient and investigator bias in assessing symptomatic improvement after percutaneous myocardial laser revascularization (PMLR) therapy. Eighty-two patients with stable angina pectoris (class III or IV) not amenable to conventional revascularization and with evidence of reversible ischemia, ejection fraction ≥25%, and myocardial wall thickness ≥8 mm were randomized to either PMLR with optimal medical therapy (n = 40) or to a sham procedure with optimal medical therapy (n = 42). With the exception of 1 laser technician, all patients, investigators, and assessors were blinded to treatment through the 12-month follow-up. The primary end point was restricted to Canadian Cardiovascular Society angina class improvement to limit the number of patients exposed to a sham procedure. Secondary assessments included medication usage, quality of life, exercise testing, ejection fraction, and hospitalizations. The incidence of serious adverse events, as determined by cardiac event-free survival at 12 months, was similar between groups. At 12 months, Canadian Cardiovascular Society angina scores improved by ≥2 classes in significantly more PMLR-treated patients than sham control patients (35% vs 14%, p = 0.04). Angina-specific quality-of-life measures were significantly higher in the PMLR group at each follow-up (p <0.05). Exercise and medication usage was similar between groups at 12 months. We conclude that PMLR therapy is reasonably safe and effective as symptomatic improvement in patients refractory to medical therapy, and that the clinical benefit is not attributable to placebo effect or investigator bias.

Transmyocardial Laser Revascularization.

Transmyocardial laser revascularization (TMR) has been performed on over 12,000 patients worldwide. Since 1990, the treatment has provided significant angina relief for symptomatic end-stage coronary disease that is refractory to medical therapy. Seventy-five percent of patients treated with TMR have demonstrated a decrease of two or more angina classes postoperatively. As a result, TMR has provided a significant improvement in quality of life for patients, resulting in fewer hospital admissions and decreased dependency on medications. Two different wavelengths of light, carbon dioxide (CO(2)) and holmium yttrium-aluminum-garnet (Ho:YAG), have been employed. Results obtained using these lasers differ. The CO(2) laser has demonstrated a perfusion benefit as well as long-term improvement in quality of life and angina relief. The Ho:YAG laser has not demonstrated these results. These differences may, in part, explain the failure of percutaneous myocardial laser revascularization. This catheter-based approach was not as successful as TMR due to its partial thickness treatment of the myocardium as well as its use of the Ho:YAG laser. In addition to the patients with end-stage coronary disease who undergo TMR as sole therapy, there are an increasing number of patients who have been treated with a combination of coronary artery bypass grafting and TMR. This provides a more complete revascularization than leaving territories ungrafted. Further enhancement of the angiogenic response seen after TMR may be seen by the addition of gene therapy to TMR treatment.

Absence of clinical signs of cardiac denervation after percutaneous myocardial laser revascularization

Background: Percutaneous myocardial revascularization with laser (PMR) is a catheter-based technique that has generated much interest in the treatment of patients with severe coronary artery disease. Several mechanisms have been proposed to explain the reported clinical benefits of this technique. Cardiac autonomic denervation is among these. Methods: We studied 32 consecutive patients with chronic severe angina not suitable for other revascularization approaches. Canadian Class Society (CCS) class clinical assessment, Naughton exercise stress test, and scintigraphic myocardial perfusion were evaluated before and 1 and 6 months after PMR. Ewing’s autonomic tests, heart rate variability (HRV), and plasmatic catecholamines were assessed before revascularization in non-diabetic and diabetic patients and repeated 1 month after PMR in 13 non-diabetics. A psychological test was carried out before PMR to evaluate the attitude towards this new procedure. Results: All the markers of autonomic cardiac control were unmodified after the procedure. Moreover, scintigraphic perfusion measured in the lasered areas was similar before and after the procedure. On the other hand, the clinical conditions significantly improved (CCS class from 3±0.8 to 1.9±0.9 at 1 month, P<0.01) and the exercise-related ischemic threshold was significantly better (from 311±28 to 453±51 s, P<0.05). The patients with a psychologically ‘positive’ expectation for this new procedure had results comparable to those with a ‘negative’ expectation. Conclusions: PMR improves symptoms in patients with end-stage coronary artery disease in the absence of any detectable clinical sign of heart denervation.

Percutaneous myocardial laser revascularization in patients with refractory angina pectoris

This study aimed to determine the safety and efficacy of percutaneous myocardial laser revascularization (PMLR). Seventy-three patients with stable angina pectoris (class III or IV) who were unsuitable for conventional revascularization and had evidence of reversible ischemia by thallium-201 scintigraphy, ejection fraction of ≥25%, and myocardial wall thickness ≥8 mm were randomized to optimal medical therapy alone (n = 37) or PMLR with optimal medical therapy (n = 36). Patients were followed up at 3, 6, and 12 months. The primary end point was exercise time. Secondary end points included angina scores, left ventricular ejection fraction, quality of life, changes in medical therapy, and hospitalizations. All 36 patients randomized to PMLR underwent the procedure successfully with no periprocedure deaths. One patient developed sustained ventricular tachycardia that required electrical cardioversion, and 1 patient developed cardiac tamponade that required surgical drainage. At 12 months, exercise times improved by 109 seconds in the PMLR group but decreased by 62 seconds in the control group (p <0.01). Angina scores improved by 2 classes in 36% of PMLR-treated patients at 12 months compared with 0% of the control patients (p <0.01). We conclude that PMLR is a relatively safe procedure that provides patients with symptomatic angina relief and improvement in exercise capacity and quality of life.

Laser revascularisation.

Patients who present with angina pectoris due to underlying coronary artery disease which is not controlled by medical therapy, and who have disease which is not amenable to conventional forms of revascularisation, present an increasing clinical problem. Laser techniques have been introduced to improve myocardial perfusion in this group of patients. The surgical technique of transmyocardial laser revascularisation has been evaluated in this patient population. Generally, there has been a good symptomatic response in terms of improvement in angina, and in some studies an increase in exercise capacity. The technique, however, does carry significant morbidity and mortality. More recently, a catheter-based technique has been introduced--percutaneous myocardial laser revascularisation. This technique seems to improve symptoms of angina, produce an increase in exercise capacity, with a much more favourable procedural risk profile.

Immediate effect of percutaneous myocardial laser revascularization on hemodynamics and left ventricular systolic function in severe angina pectoris

Experimental data suggest that myocardial revascularization with a high-energy laser may cause a significant reduction in left ventricular (LV) function immediately after creation of myocardial channels. We sought to determine if percutaneous myocardial laser revascularization (PMR) causes immediate deterioration in hemodynamic parameters or regional LV systolic function. PMR was performed in 40 patients (mean age 62.9 ± 10.8 years) using the Eclipse Holmium laser (26 had PMR alone; 14 patients underwent PMR plus percutaneous coronary intervention). Intracardiac pressures and left ventriculograms were recorded before and after PMR. Regional wall motion was assessed using the centerline method. A mean of 18 ± 5 channels were created per patient. There was no significant change in LV ejection fraction immediately after PMR (56 ± 9% vs 55 ± 10%, p = 0.25). No deterioration in regional wall motion was demonstrated in the lased region (mean chord motion for anterior wall PMR: −1.5 ± 0.8 before vs −1.5 ± 0.8 after the procedure, p = 0.93; inferior wall PMR: −1.5 ± 0.9 before vs −1.6 ± 0.8 after the procedure, p = 0.43). Similarly, there was no change in the number of hypokinetic chords in the treated region. Systemic blood pressure, LV end-diastolic pressure, heart rate, and right-sided heart pressures were not significantly different after laser revascularization. In patients with refractory angina, PMR did not cause immediate deterioration in hemodynamic status or regional LV function.

Sustained clinical benefit two years after percutaneous myocardial laser revascularization in patients with end-stage coronary artery disease Bernward Lauer, Fabian Stahl, Sophia Bratanow, Gerhard Schuler. University Leipzig, Heart Center, Leipzig, Germany

Sustained clinical benefit two years after percutaneous myocardial laser revascularization in patients with end-stage coronary artery disease Bernward Lauer, Fabian Stahl, Sophia Bratanow, Gerhard Schuler. University Leipzig, Heart Center, Leipzig, Germany

Percutaneous myocardial laser revascularisation (PMR): Is the symptomatic benefit maintained to 2 years? Richard J. Allen, Simon R. Redwood, D. J. Coltart. Guy's and St Thomas' Hospital Trust, London, United Kingdom

Percutaneous myocardial laser revascularisation (PMR): Is the symptomatic benefit maintained to 2 years? Richard J. Allen, Simon R. Redwood, D. J. Coltart. Guy's and St Thomas' Hospital Trust, London, United Kingdom