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

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Abstract

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.

Section snippets

Participants

After referral for possible laser revascularization, consenting patients were assessed for suitability at the 2 participating institutions (Haukeland Hospital, Bergen, Norway, and Ulleval University Hospital, Oslo, Norway). The following criteria were necessary for inclusion in the study: stable Canadian Cardiovascular Society (CCS) class III or IV angina refractory to maximally tolerated doses of ≥2 antianginal medications; evidence of reversible myocardial ischemia on exercise testing or

Patient characteristics

Patient follow-up is shown in Figure 1; 82 patients were randomized (PMLR n = 40, sham n = 42). All baseline characteristics (Table 1) were similar between groups.

Procedural outcomes

In each group, comparable channel placements were made (PMLR 19 ± 4.5 vs sham 20 ± 3.6; p = 0.30) over comparable procedure durations (PMLR 36 ± 16 minutes vs sham 37 ± 12 minutes; p = 0.66). The primary target region within the left ventricle was the lateral wall (n = 67; 82%), followed by the inferior (n = 51; 62%) and anterior (n

Discussion

Surgical laser revascularization was developed for the treatment of patients unsuitable for conventional therapies due to diffuse disease5 and has been evaluated in 5 prospective, randomized trials against optimal medical therapy.6, 7, 8, 9, 10 Results at 1 year show superior angina relief and improved event-free survival/quality of life, yet with equivocal results in perfusion improvement. PMLR was developed as a less invasive alternative11 to avoid general anesthesia/thoracotomy with the

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      Citation Excerpt :

      5) The presence of inter-study variability between sham and not sham studies was not ascribable to mean or median age of patients but possibly to other factors. 6) The absence of psychological and psychiatric profile that is relevant for studies were the placebo effect have to be evaluated represents a very important confounding factor [10,22,24–73,78,79]. 7) A percentage of 5% of participants lost to the follow-up has been extracted from 30 on the 52 studies examined (ref.).

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    This study was supported by a grant from The Bergen Heart Foundation, Bergen, Norway.

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