Increased risks for random errors are common in outcomes graded as high certainty of evidence.

OBJECTIVES: The aim of article was to assess the risk for random errors in outcomes graded as high certainty of evidence (CoE). STUDY DESIGN AND SETTING: We randomly selected 100 Cochrane reviews with dichotomous outcomes rated as high CoE using Grading of Recommendations Assessment, Development, and Evaluation. To detect increased risks for random errors, two investigators independently conducted trial sequential analysis using conventional thresholds for type I (α = 0.05) and type II (ß = 0.10) errors. We dually regraded all outcomes with increased risks for random errors and conducted multivariate logistic regression analyses to determine predictors of increased risks for random errors. RESULTS: Overall, 38% (95% confidence interval: 28-47%) of high CoE outcomes had increased risks for random errors. Outcomes assessing harms were more frequently affected than outcomes assessing benefits (47% vs. 12%). Regrading of outcomes with increased random errors showed that 74% should have been downgraded based on current guidance. Regression analyses rendered small absolute risk differences (P = 0.009) and low number of events (P = 0.001) as significant predictors of increased risks for random errors. CONCLUSION: Decisionmakers need to be aware that outcomes rated as high CoE often have increased risks for false-positive or false-negative findings.

Transmyocardial laser revascularization. Personal experience.

BACKGROUND: Indirect revascularization is a therapeutic approach in case of severe angina not suitable for percutaneous or surgical revascularization. Transmyocardial revascularization (TMR) is one of the techniques used for indirect revascularization and it allows to create transmyocardial channels by a laser energy bundle delivered on left ventricular epicardial surface. Benefits of the procedure are related mainly to the angiogenesis caused by inflammation and secondly to the destruction of the nervous fibers of the heart. PATIENTS AND METHOD: From September 1996 up to July 1997, 14 patients (9 males - 66.7%, mean age 64.8±7.9 years) underwent TMR. All patients referred angina at rest; Canadian Angina Class was IV in 7 patients (58.3%), III in 5 (41.7%). Before the enrollment, coronarography was routinely performed to find out the feasibility of Coronary Artery Bypass Graft (CABG): 13 patients (91,6%) had coronary arteries lesions not suitable for direct revascularization; this condition was limited only to postero-lateral area in one patient submitted to combined TMR + CABG procedures. RESULTS: Mean discharge time was 3,2±1,3 days after surgery. All patients were discharged in good clinical conditions. Perfusion thallium scintigraphy was performed in 7 patients at a mean follow-up of 4±2 months, showing in all but one an improvement of perfusion defects. Moreover an exercise treadmill improvement was observed in the same patients and all of them are in good clinical conditions, with significantly reduced use of active drugs. CONCLUSION; Our experience confirms that TMR is a safe and feasible procedure and it offers a therapeutic solution in case of untreatable angina. Moreover, it could be a hybrid approach for patients undergoing CABGs in case of absence of vessels suitable for surgical approach in limited areas of the heart.