Meta-analysis of clinical efficacy of pulsed radio frequency energy treatment.

OBJECTIVE: To statistically evaluate published clinical efficacy data related to the use of pulsed radio frequency energy (PRFE) therapy in 3 clinical applications. BACKGROUND: Numerous clinical studies have reported efficacy outcomes for PRFE therapy use in the palliative treatment of both postoperative and nonpostoperative pain and edema, and for its use as an adjunctive wound-healing (WH) therapeutic. Although diverse in design and endpoint, these studies are amenable to systematic review using both a vote-counting and P-value combination meta-analytic technique. METHODS: A meta-analysis of efficacy outcomes reported in clinical trials was performed using a vote-counting procedure. In addition, when possible, the sum of logs method of P-value combination was used to determine a significance level for the combined evidence within each endpoint and clinical area. RESULTS: Of the 186 clinical articles identified after application of selection criteria, there were 25 controlled trials that met criteria for inclusion in vote-counting and P-value combination methods and were used for formal statistical analysis. In total, 1332 patients receiving PRFE treatment were studied. Vote-counting procedure applied to clinical outcomes from controlled studies resulted in a greater number of positive outcomes than neutral outcomes, and zero negative outcomes, for each of the clinical application groups evaluated. The sum of logs P-value method found statistically significant improvement in pain, reduction in edema, and improvement in WH outcomes. CONCLUSIONS: On the basis of statistical evaluation of published clinical efficacy data, there is strong statistical evidence that PRFE therapy is effective in the treatment of postoperative and nonpostoperative pain and edema and in WH applications.

Early hypothermia in severely injured trauma patients is a significant risk factor for multiple organ dysfunction syndrome but not mortality.

OBJECTIVE: To evaluate the relationship of early hypothermia to multiple organ failure and mortality in a prospectively-collected database of severely injured trauma patients. METHODS: This prospective observational study was performed at 7 level I trauma centers over a 16-month period. Severely injured trauma patients with signs of hypoperfusion (eg, base deficit, hypotension) and need for blood transfusion during their early hospital course were followed for 24 hours with near infrared spectroscopy-derived tissue oxygen saturation (StO2) and other variables for 28 days to evaluate outcomes including multiple organ dysfunction syndrome (MODS) and death. Early hypothermia was defined as the presence of a temperature <35°C [corrected] anytime within the first 6 hours of hospitalization. Comparisons between groups were made using the Wilcoxon Two-Sample test for continuous variables and either the Fisher exact or chi2 test for categorical variables. Multivariate logistic regression was utilized to understand the effect of hypothermia on outcome (MODS and mortality). RESULTS: Hypothermia was very common in this cohort of patients, present in 43% of patients enrolled (155/359). Hypothermic patients were 3 times more likely than normothermic patients to develop MODS (21% vs. 9%, P = 0.003). Hypothermic patients did not have an increased incidence of mortality (16% vs. 12%, P= 0.2826). Base deficit in hypothermic patients did not discriminate between patients who did or did not develop MODS (9.8 +/- 4.6 mEq/L vs. 9.4 +/- 4.4 mEq/L). In contrast, base deficit in hypothermic patients discriminated with respect to mortality (14.6 +/- 7.2 mEq/L versus 9.5 +/- 4.5 mEq/L; P 0.0021), but this effect was not observed in normothermic patients [corrected]. Significant predictors of MODS using multivariate analysis included minimum StO2 (P= 0.0014) and hypothermia (P = 0.0371). Predictors for mortality using multivariate analysis included minimum StO2 (P= 0.0021) and base deficit (P= 0.0454), but not hypothermia (P= 0.5289). Hypothermia remained a significant risk factor for MODS when systolic blood pressure, volume of fluid, and volume of blood infused were included in the multivariate model. CONCLUSION: Hypothermia is common in severely injured trauma patients (nearly half of patients in this series) and is a significant risk factor for MODS but not mortality. The predictive value of base deficit for development of MODS is blunted in the presence of hypothermia. A low StO2 value predicts MODS and mortality in trauma patients and is a durable measure in both normothermic and hypothermic patient groups.

Propensity Score-Adjusted Comparison of Long-Term Outcomes Among Revascularization Strategies for Critical Limb Ischemia.

BACKGROUND: Few studies have compared long-term outcomes among specific treatment modalities for critical limb ischemia. The aim of this study was to compare long-term outcomes with percutaneous transluminal angioplasty (PTA), stent placement, atherectomy, or surgical bypass in patients diagnosed with critical limb ischemia. METHODS: In this observational study using Medicare claims data, we identified incident cases with a primary critical limb ischemia diagnosis who received PTA, stent placement, atherectomy, or surgical bypass. We used propensity score weighting to determine the association of treatment type with all-cause mortality and major (above ankle) amputation over 4 years follow-up. RESULTS: Among 36 860 patients (10 904 PTA; 11 295 stent placement; 4422 atherectomy; 10 239 surgical bypass), all-cause mortality over 4 years was 49.3% with atherectomy, 51.4% with surgical bypass, 53.7% with stent placement, and 54.7% with PTA (P<0.05 for all pairwise comparisons). Major amputation rates over 4 years were 6.8% with atherectomy, 7.8% with stent placement, 8.1% with PTA, and 10.8% with surgical bypass (P<0.05 for all pairwise comparison except PTA versus stent). CONCLUSIONS: Among Medicare beneficiaries who received PTA, stent placement, atherectomy, or surgical bypass for critical limb ischemia, high mortality and major amputation rates were observed with minor differences among treatment groups. Statistically significant group differences of uncertain clinical importance were observed for several comparisons. Results from observational research may be susceptible to bias because of unmeasured confounders and, therefore, these comparative results should be interpreted with caution.

A Bayesian meta-analysis comparing AngioJet thrombectomy to percutaneous coronary intervention alone in acute myocardial infarction.

OBJECTIVE: The purpose of this meta-analysis was to compare outcomes for AngioJet thrombectomy versus percutaneous coronary intervention (PCI) without thrombectomy in acute myocardial infarction (AMI) patients. BACKGROUND: PCI is the preferred treatment for revascularizing the infarct-related artery in patients with AMI. There is controversy about the benefits of thrombectomy as an adjunct to PCI. METHODS: AMI studies published between January 1, 1999, and March 1, 2007, were used to compare AngioJet thrombectomy plus PCI to PCI alone. Bayesian meta-analytic estimates were used to estimate the odds ratios (95% CI) for short-term mortality, major adverse cardiac events (MACE), and final TIMI 3 flow. RESULTS: The AngioJet data included 11 studies and 1,018 patients. The PCI data included 81 studies and 24,076 patients. The AngioJet group included more patients with large thrombus burden, rescue PCI after failed thrombolytic therapy, and longer symptom duration compared to the PCI group. Despite the higher risk profile of AngioJet patients, the groups had similar odds of short-term mortality, 0.98 (0.53, 1.50), MACE, 1.25 (0.54, 2.40), and final TIMI 3 flow, 1.12 (0.70, 2.27). CONCLUSION: AngioJet thrombectomy results in clinical and angiographic outcomes that are similar to PCI in lower risk AMI patients. These observations suggest that AngioJet thrombectomy may reduce the additional risk associated with visible thrombus in the infarct-related lesion.

Low StO2 measurements in surgical intensive care unit patients is associated with poor outcomes.

BACKGROUND: Near-infrared spectroscopy-derived tissue hemoglobin saturation (StO2) is a noninvasive measurement that reflects changes in microcirculatory tissue perfusion. Previous studies in trauma patients have shown a correlation between low StO2 levels and mortality, organ failure, and severity of injury. The goals of this study were to identify the incidence of low StO2 in the critically ill patient population of a surgical intensive care unit (SICU) and evaluate the relationship of low StO2 and clinical outcomes. METHODS: We conducted a prospective cohort study at the University of Minnesota Medical Center. After institutional review board approval, 620 patients admitted to the SICU between July 2010 and July 2011 were screened for enrollment. Patients with an expected ICU length of stay of less than 24 hours were excluded. In the 490 patients who met inclusion criteria, StO2 measurements were obtained from the thenar eminence one to three times daily for the length of the ICU stay, up to 14 days. Outcome data included 28-day hospital mortality; ICU readmission; ventilator-free, ICU-free, and hospital-free days; and the need for lifesaving interventions. RESULTS: The overall incidence of low StO2 (<70%) was 11% of the patients per day. Patients with at least 1 day in the SICU with an StO2 measurement of less than 70% had higher rates of ICU readmission and fewer ventilator-free, ICU-free, and hospital-free days compared with those who did not. Mortality (28-day in-hospital) trended higher for these patients but was not statistically significant. An increase in the number of days with StO2 less than 70% was also associated with fewer ventilator-free, ICU-free, and hospital-free days. CONCLUSION: Low StO2 (<70%) is common and associated with poor outcomes in SICU patients. Near-infrared spectroscopy represents a potentially useful, noninvasive adjunct to monitoring of critically ill patients. LEVEL OF EVIDENCE: Prognostic study, level II.