Preoperative prediction of residual back pain after vertebral augmentation for osteoporotic vertebral compression fractures: Initial application of a radiomics score based nomogram.

Background: Most patients with osteoporotic vertebral compression fracture (OVCF) obtain pain relief after vertebral augmentation, but some will experience residual back pain (RBP) after surgery. Although several risk factors of RBP have been reported, it is still difficult to estimate the risk of RBP preoperatively. Radiomics is helpful for disease diagnosis and outcome prediction by establishing complementary relationships between human-recognizable and computer-extracted features. However, musculoskeletal radiomics investigations are less frequently reported. Objective: This study aims to establish a radiomics score (rad-score) based nomogram for the preoperative prediction of RBP in OVCF patients. Methods: The training cohort of 731 OVCF patients was used for nomogram development, and the validation cohort was utilized for performance test. RBP was determined as the score of visual analogue scale ≥ 4 at both 3 and 30 days following surgery. After normalization, the RBP-related radiomics features were selected to create rad-scores. These rad-scores, along with the RBP predictors initially identified by univariate analyses, were included in the multivariate analysis to establish a nomogram for the assessment of the RBP risk in OVCF patients preoperatively. Results: A total of 81 patients (11.2%) developed RBP postoperatively. We finally selected 8 radiomics features from 1316 features extracted from each segmented image to determine the rad-score. Multivariate analysis revealed that the rad-score plus bone mineral density, intravertebral cleft, and thoracolumbar fascia injury were independent factors of RBP. Our nomograms based on these factors demonstrated good discrimination, calibration, and clinical utility in both training and validation cohorts. Furthermore, it achieved better performance than the rad-score itself, as well as the nomogram only incorporating regular features. Conclusion: We developed and validated a nomogram incorporating the rad-score and regular features for preoperative prediction of the RBP risk in OVCF patients, which contributed to improved surgical outcomes and patient satisfaction.

STABLE-SR (Electrophysiological Substrate Ablation in the Left Atrium During Sinus Rhythm) for the Treatment of Nonparoxysmal Atrial Fibrillation: A Prospective, Multicenter Randomized Clinical Trial.

BACKGROUND: Circumferential pulmonary vein isolation (CPVI) alone or combined with adjuvant substrate modifications is unsatisfactory for atrial fibrillation (AF) control in nonparoxysmal AF patients. Ablation targeting the fibrotic areas after CPVI (STABLE-SR [Electrophysiological Substrate Ablation in the Left Atrium During Sinus Rhythm]) is a newly evolved substrate modification strategy. METHODS AND RESULTS: In this multicenter, randomized clinical trial, 229 symptomatic nonparoxysmal AF patients were 1:1 randomized to STABLE-SR group (n=114) or conventional STEPWISE group (n=115). In the STABLE-SR group, after CPVI, cavotricuspid isthmus ablation and cardioversion to sinus rhythm, left atrial high-density mapping was performed. Areas with low-voltage and complex electrogram were further homogenized and eliminated, respectively. Dechanneling would be done if necessary. In the STEPWISE group, additional linear lesions and defragmentation were performed.The primary end point was freedom from documented atrial tachyarrhythmias for ≥30 s after a single ablation procedure without antiarrhythmic medications at 18 months. At 18 months, 74.0% of the patients in the STABLE-SR group and 71.5% in the STEPWISE group (hazard ratio, 0.78; 95% confidence interval, 0.47-1.29; P=0.325) achieved success according to intention-to-treat analysis. However, less procedure time (186.8±52.7 versus 210.5±48.0 minutes, P<0.001), reduced post-CPVI fluoroscopic time (11.0±7.8 versus 13.7±8.9 minutes, P=0.006), and shorter energy delivery time (60.1±25.1 versus 75.0±24.3 minutes, P<0.001) were observed in the STABLE-SR group compared with the STEPWISE group. CONCLUSIONS: STABLE-SR is a simplified, personalized, and effective ablation strategy in nonparoxysmal AF patients. More importantly, over 50% nonparoxysmal AF patients do not need further ablation beyond CPVI and therefore can avoid excessive ablation. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01761188.

Catheter Ablation of Nonparoxysmal Atrial Fibrillation Using Electrophysiologically Guided Substrate Modification During Sinus Rhythm After Pulmonary Vein Isolation.

BACKGROUND: The high incidence of postprocedural atrial tachycardia reduces the absolute arrhythmia-free success rate of extensive ablation strategies to treat nonparoxysmal atrial fibrillation (NPAF). We hypothesized that a strategy of targeting low-voltage zones and sites with abnormal electrograms during sinus rhythm (SR-AEs) in the left atrium after circumferential pulmonary vein isolation and cavotricuspid isthmus ablation in patients with NPAF is superior. METHODS AND RESULTS: A total of 86 consecutive patients with NPAF were enrolled in study group. After circumferential pulmonary vein isolation, cavotricuspid isthmus ablation and cardioversion to SR, high-density mapping of left atrium was performed. Areas with low-voltage zone and SR-AE were targeted for further homogenization and elimination, respectively; 78 consecutive sex- and age-matched patients with NPAF who were treated with the stepwise approach served as the historical control group. In the study group, 92% (79/86) were successfully cardioverted after circumferential pulmonary vein isolation and cavotricuspid isthmus ablation. Among the patients converted to SR, 70% (55/79) had low-voltage zone and SR-AE and received additional ablation, whereas in 30% (24/79) without SR-AE or low-voltage zone, no further ablation was performed. During a follow-up period of >30 months, the Kaplan-Meier estimated probability to maintain SR at 24 months was 69.8% versus 51.3%. And after a single procedure, 3.5% (3/86) developed postprocedural atrial tachycardia in study group, compared with 30% (24/78) in control group (P=0.0003). CONCLUSIONS: A strategy of selective electrophysiologically guided atrial substrate modification in SR after circumferential pulmonary vein isolation and cavotricuspid isthmus ablation is clinically more effective than the stepwise approach for NPAF ablation. CLINICAL TRIAL REGISTRATION: URL: http://clinicaltrials.gov. Unique identifier: NCT01716143.

[Effects of tetramethylpyrazine on fibrosis of atrial tissue and atrial fibrillation in a canine model of congestive heart failure induced by ventricular tachypacing].

OBJECTIVE: To explore the effects of tetramethylpyrazine (TMP) on fibrosis of atrial tissue and atrial fibrillation in a canine model of congestive heart failure (CHF) induced by ventricular tachypacing. METHODS: Twenty-one healthy mongrel dogs were randomly divided into three groups, which were normal control group, untreated group and TMP-treated group. Atrial fibrillation (AF) was induced by burst of atrial pacing, after the canine model of CHF was established. The atrial tissues were sampled and stained with Mallory's trichromic stains, then the fibrosis in the atrial tissues was analyzed. The left ventricular ejection fraction (LVEF) was evaluated by echocardiography. The levels of angiotensin II (AngII), aldosterone (ALD), amino-terminal peptide of type III procollagen (PIIINP)ìlaminin (LN) and hyaluronic acid (HA) in peripheral blood were examined by radioimmunoassay. RESULTS: The LVEF was significantly decreased in the untreated group as compared with that in the normal control group (P<0.01), while the frequencies of AF and sustaining AF were significantly increased and the AF duration was obviously prolonged in the untreated group as compared with those in the normal control group (P<0.01). The fibrosis degree in the left or right atrial tissue in the untreated group was more serious than that in the normal control group (P<0.01). The AF duration was positively correlated with the fibrosis degree in the left atrial tissue (r=0.84, P=0.018). The levels of AngII, ALD, PIIINP and HA in peripheral blood were significantly higher in the untreated group than those in the normal control group (P<0.05 or P<0.01). The level of AngII was positively correlated with the level of ALD in peripheral blood (r=0.759, P=0.048). The LVEF and the frequency of sustaining AF were both significantly improved in the TMP-treated group as compared with those in the untreated group (P<0.05). The fibrosis in the left or right atrial tissue in the untreated group was more serious than that in the untreated group (P<0.01). The levels of AngII and PIIINP in peripheral blood were also markedly higher in the TMP-treated group than those in the untreated group (P=0.05, P=0.01). CONCLUSION: Tetramethylpyrazine has the effect of reducing the fibrosis degree of atrial tissue in dogs with CHF, and this efficacy may be related to the mechanism of decreasing the frequency of AF and shortening the AF duration.