Disease Progression Stages and Burden in Patients with Duchenne Muscular Dystrophy Using Administrative Claims Supplemented by Electronic Medical Records

INTRODUCTION

This study aims to identify stages of Duchenne muscular dystrophy (DMD) and assess the disease burden by progression stage using real-world administrative claims supplemented by relevant electronic medical record (EMR) data.

METHODS

Claims and EMR data from the Decision Resources Group's Real World Data Repository (2011-2020) were used to identify patients with DMD by diagnosis code and to stratify them into four disease stages by diagnosis and procedure markers reflective of DMD progression. Clinical and medical history data from the Cooperative International Neuromuscular Research Group (CINRG) were used to validate the developed claims-based staging algorithm. The distribution and drivers by disease stage, as well as disease burden, were examined.

RESULTS

A total of 938 (94%) of patients with DMD identified in claims/EMR data had sufficient information for stage classification. Patients were classified by stage based on patient characteristics and the presence or absence of progression markers such as genetic testing, wheelchair usage, scoliosis treatment, or ventilation assistance. Average ages at stages 1-4 are 7, 13, 18, and 23 years, respectively. Using natural history data, the claims-based staging algorithm was validated with high sensitivity and specificity rates. Both healthcare resource utilization and medical charges increased by stage. For example, the average annualized total charges were $17,688 (stage 1), $36,868 (stage 2), $72,801 (stage 3), and $167,285 (stage 4).

CONCLUSIONS

Large-scale claims data supplemented by EMR data can be used to characterize DMD progression and evaluate disease burden which may inform the design of future real-world studies about DMD.

Differentiating border-zone tissue from post-infarct scar using ripple mapping during VT ablation

Funding Acknowledgements

Type of funding sources: None.

Background

Areas of post-infarct ventricular scar and border-zone slow conduction are often highlighted on a bipolar voltage map with generalized values 0.5mV–1.5mV. The true voltage that differentiates regions of conducting from non-conducting tissue is unknown. Ripple Mapping (RM)displays allows conducting tissue to be seen as areas supporting Ripple activation, and non-conducting tissue as areas devoid of Ripple activation.

Purpose

We describe application of Ripple Maps to differentiate areas of scar from conducting tissue during ischemic VT ablation.

Methods

Dense bipolar voltage maps were created (Pentaray catheter, pacing 80-100bpm) and presented as a single value (e.g. 0.5mV-0.5mV) to binarize the color display (red and purple). RMs were superimposed on the voltage map and played above a pre-set noise threshold (>0.05mV). The voltage map mV limit was sequentially reduced ("border-zone threshold") until only those areas devoid of Ripple bars appeared red. The surrounding border-zone supporting ripple activation thus appeared purple. We performed off-line analysis of border-zone voltage thresholds from a series of RM guided VT ablations.

Results

10 consecutive patients (LVEF 32.3±7.5%) with remote myocardial infarction underwent VT ablation (median 19days (IQR 8-33) since last VT). Bipolar voltage mapping (5873±2841 points, median shell area 224cm2), revealed voltages<0.5mV covered a median 11% (IQR 7-17%) of the shell. The border-zone voltage threshold was median 0.2mV (range 0.12mV - 0.3mV). Non-conducting tissue below this value covered only median 5% (IQR 3-7%) of the entire shell. VT was mappable in 4 patients, and the isthmus was bordered by tissue below the same border-zone threshold as found in normal rhythm. The border-zone was homogenized with ablation(40-50W, median 29 mins (IQR 22-33), and clinical VT was non-inducible in all, and 9 pts (91%) remain sustained VT-free at median 90-day follow-up (IQR 23-139), 2-weeks blanking period).

Picture 1 presents an infero-lateral LV infarct collected in an RV paced rhythm (7340points) and displayed at conventional bipolar voltage settings 0.5-1.5mV. Tissue with voltages<0.5mV appear red and cover 30% of the total area. In this case, this border-zone voltage threshold was defined as 0.25mV. Non-conducting tissue, seen as areas devoid of ripple bars below this value, now appeared as red, and covered only 11% of the total area. Picture 2 demonstrates the morphologies of 4 poorly tolerated induced VTs during this case. Each had near perfect pacemaps to the exit sites of border-zone tissue defined using this approach, and were targets for ablation resulting in complete non-inducibility and no VT recurrence in early follow-up.

Conclusion

The bipolar voltage that differentiates putative scar from bordering conducting tissue is unique to each patient, and far lower than 0.5mV-1.5mV. RM presents a practical approach to visualize the border-zone activation to guide ablation.

Tazemetostat in relapsed/refractory follicular lymphoma: a propensity score-matched analysis of E7438-G000-101 trial outcomes

Purpose: In the tazemetostat E7438-G000-101 trial of relapsed/refractory (R/R) follicular lymphoma (FL), apparent superior efficacy was suggested for mutant-type (MT) EZH2 versus wild-type (WT) status. However, clinical disparities might have contributed to this conclusion. This study aimed to estimate outcomes after minimizing differences in baseline characteristics.

Methods: Propensity scores for each participant with WT (n = 54) and MT (n = 45) status were generated based on the likelihood of being selected given their baseline characteristics. Participants were matched using a 1:1 nearest-neighbor approach.

Results: The propensity-matched sample included 56 participants (28 WT, 28 MT). Objective response rates (95% confidence interval [CI]) were 35% (22–48) in WT and 69% (55–83) in MT prior to matching and 50% (31–69) in WT and 71% (54–88) in MT after matching. Median progression-free survival values (95% CI) were 11.1 (5.4–16.7) in WT and 13.8 months (11.1–22.1) in MT prior to matching and 14.3 (11.1–∞]) and 14.8 months (10.7–∞]) in WT and MT matched groups, respectively.

Conclusions: This analysis suggests that efficacy outcomes for tazemetostat observed in participants with WT EZH2 R/R FL may have been similar to those in participants with MT had the 2 cohorts been more closely matched.

A Matching-Adjusted Indirect Comparison of Single-Arm Trials in Patients with Relapsed or Refractory Follicular Lymphoma Who Received at Least Two Prior Systemic Treatments: Tazemetostat was Associated with a Lower Risk for Safety Outcomes Versus the PI3-Kinase Inhibitors Idelalisib, Duvelisib, Copanlisib, and Umbralisib

INTRODUCTION

Tazemetostat is an enhancer of zeste homolog 2 (EZH2) inhibitor recommended for patients with relapsed/refractory (R/R) follicular lymphoma (FL) after demonstrating single-agent, antitumor activity in patients with wild-type or mutant EZH2. The phosphoinositide 3-kinase (PI3K) inhibitors idelalisib, copanlisib, umbralisib and (formerly) duvelisib are indicated for third-line, fourth-line, and later (3L/4L+) treatment of R/R FL. The objective of this analysis was to provide an indirect treatment comparison of tazemetostat with each PI3K inhibitor for 3L/4L+ R/R FL treatment.

METHODS

A systematic literature review was conducted to identify trials for idelalisib (DELTA), duvelisib (DYNAMO), copanlisib (CHRONOS-1 Part B), and umbralisib (UNITY-NHL) in 3L+ R/R FL. Matching-adjusted indirect comparisons were conducted by weighting tazemetostat individual patient data with available baseline characteristics from each comparator trial: age, Eastern Cooperative Oncology Group performance status, disease stage, histology, prior treatment lines, prior stem cell therapy, progression within 24 months, and refractory status to last therapy. Only the tazemetostat trial included patients with grade 3b or transformed FL, or recorded EZH2 mutation status. Primary safety outcomes included risk of grade ≥ 3 treatment-emergent adverse events (TEAEs); primary efficacy outcomes included objective response rate (ORR).

RESULTS

Matched patients treated with tazemetostat had lower relative risk (RR) for all grouped safety outcomes, including any grade ≥ 3 TEAEs, compared with idelalisib (RR = 0.45), duvelisib (RR = 0.35), copanlisib (RR = 0.37), and umbralisib (RR = 0.65; all, p < 0.01), any serious TEAE, and any TEAE leading to dose reduction, drug discontinuation, or interruption. The ORR was not significantly different for tazemetostat versus other treatments (idelalisib 43% vs 56%, p = 0.16; duvelisib 48% vs 47%, p = 0.91; copanlisib 49% vs 61%, p = 0.11; and umbralisib 57% vs 47%, p = 0.10).

CONCLUSIONS

In this statistically adjusted comparison, tazemetostat was associated with lower RR for safety outcomes versus idelalisib, duvelisib, copanlisib, and umbralisib, while achieving similar efficacy outcomes.

Hematopoietic stem cell transplantation for hemoglobinopathies: Progress and prospects

Allogeneic bone marrow transplantation from an HLA-identical donor is currently the only means of curing thalassemia . Transplant outcome depends upon the presence of risk factors (hepatomegaly, portal fibrosis and poor quality of chelation). patients are defined to have class I - if no risk factor, class II with one or two and class III - if all three risk factors are present. For patients under 16 years of age, for class I, class II and III the probabilities of survival are approximately 95%, >80% and 60-70%, respectively. The risk of transplant related morbidity& mortality is low when transplant is done at an early age. Currently, busulfan, cyclophospahmide and antithymocyte globulin based combination is used for conditioning. More than 200 patients with sickle cell disease (SCD) have undergone allogeneic SCT with long term survival in >80% of patients. Results are better if donor is an HLA-identical sibling and if transplant is done early in the course of disease. Presently, experience with reduced intensity SCT and matched unrelated donor transplant is limited to recommend their routine use.

National and regional description of healthcare measures among adult Medicaid beneficiaries with schizophrenia within the United States

AIMS

Provide the first national description across the US of variations in healthcare measures in 2018 among Medicaid beneficiaries with schizophrenia.

MATERIALS AND METHODS

Adult beneficiaries with ≥2 diagnoses for schizophrenia, and continuous enrollment with consistent geographical data in all of 2018 were identified from Transformed Medicaid Statistical Information System (T-MSIS) Analytic Files (TAF) data for 45 of 50 states. Antipsychotic (AP) utilization rates, including long-acting injectable APs (LAIs), quality metrics, and all-cause healthcare resource utilization and costs for claims submitted to Medicaid were reported nationally and by state. Pearson correlation evaluated associations between LAI utilization and total healthcare costs at state and county levels.

RESULTS

Across the US 688,437 patients with schizophrenia were identified. The AP utilization rate was 51% (state range: 24-77%), while the LAI utilization rate was 13% (range: 4-26%). The proportion of patients adherent to any AP was 56% (range: 19-73%). Within 30 days post-discharge from an inpatient admission, 22% (range: 8-58%) of patients had an outpatient visit, and 12% (range: 4-48%) had a readmission. The proportion of patients with ≥1 inpatient admission and ≥1 emergency room visit was 34% (range: 19-82%) and 45% (range: 20-70%). Per-patient-per-year total healthcare costs averaged $32,920 (range: $717-$93,972). At the county level, a weak negative correlation was observed between LAI utilization and total healthcare costs.

LIMITATIONS

This study included Medicaid beneficiaries enrolled with pharmacy and medical benefits, including beneficiaries dually eligible for Medicare; results cannot be generalized to the overall schizophrenia population or those with other payer coverage.

CONCLUSIONS

In 2018, half of beneficiaries with schizophrenia did not submit any claims for APs to Medicaid, nearly half had an emergency room visit, and one-third had an inpatient admission. Moreover, healthcare measures varied considerably across states. These findings may indicate unmet treatment needs for Medicaid beneficiaries with schizophrenia.

Primitive neuroectodermal tumor of the kidney: a rare case

Background

Primitive neuroectodermal tumor commonly occurs in bones and is equivalent to Ewing’s sarcoma. Very few cases have been reported in the literature and they had a very different presentation and very aggressive behavior.

Case presentation

We present a case of a young 23-year-old male who presented with complaints of pain in left lumbar region of abdomen since 8 months and hematuria off and on. CT scan of the abdomen was done which revealed a large heterogeneously enhancing mass lesion in the left lumbar region arising from the superior and mid-pole of left kidney showing multiple non-enhancing necrotic areas. A diagnosis of left renal cell carcinoma was kept. Through the transperitoneal approach, the left kidney was approached and a left radical nephrectomy was done. The histopathology report revealed the tumor cells to be positive for CD99 and focally positive for Vimentin and negative for cytokeratin thereby making a diagnosis of primary neuroectodermal tumor (PNET).

Conclusions

Renal PNET is a rare renal malignancy that should be kept in the differential diagnosis of a renal SOL especially when it is a presenting feature in adolescent and young adult. It has a very aggressive course and multimodal therapy has to be considered in its treatment

COVID-19-associated mucormycosis presenting to the Emergency Department-an observational study of 70 patients

BACKGROUND

Mucormycosis (MM) is a deadly opportunistic fungal infection and a large surge in COVID-19-associated mucormycosis (CAM) is occurring in India.

AIM

Our aim was to delineate the clinico-epidemiological profile and identify risk factors of CAM patients presenting to the Emergency Department (ED).

DESIGN

This was a retrospective, single-centre, observational study.

METHODS

We included patients who presented with clinical features or diagnosed MM and who were previously treated for COVID-19 in last 3 months of presentation (recent COVID-19) or currently being treated for COVID-19 (active COVID-19). Information regarding clinical features of CAM, possible risk factors, examination findings, diagnostic workup including imaging and treatment details were collected.

RESULTS

Seventy CAM patients (median age: 44.5 years, 60% males) with active (75.7%) or recent COVID-19 (24.3%) who presented to the ED in between 6 May 2021 and 1 June 2021, were included. A median duration of 20 days (interquartile range: 13.5-25) was present between the onset of COVID-19 symptoms and the onset of CAM symptoms. Ninety-three percent patients had at least one risk factor. Most common risk factors were diabetes mellitus (70%) and steroid use for COVID-19 disease (70%). After clinical, microbiological and radiological workup, final diagnosis of rhino-orbital CAM was made in most patients (68.6%). Systemic antifungals were started in the ED and urgent surgical debridement was planned.

CONCLUSION

COVID-19 infection along with its medical management have increased patient susceptibility to MM.

Effects of metreleptin in patients with lipodystrophy with and without baseline concomitant medication use

OBJECTIVE

To evaluate the effects of metreleptin in distinct subgroups of patients with generalized lipodystrophy (GL) and partial lipodystrophy (PL), using multivariate linear regression modeling to account for the role of patients' baseline usage of concomitant glucose and lipid-lowering medications and other covariates on their outcomes.

MATERIALS AND METHODS

A post-hoc statistical analysis of two published single-arm, interventional, phase 2 clinical trials at NIH was conducted. Concomitant medication use was assessed for the clinical trial population using prescription fill data, measured at baseline and the post-one year following metreleptin initiation. Pre-specified co-primary efficacy endpoints measured were change from baseline in HbA1c at month 12, and the percent change from baseline in fasting serum triglycerides (TG) at month 12. Descriptive and statistical analyses were conducted for the overall population, the separate populations with GL and PL, and additional PL subgroups defined by baseline metabolic markers of elevated HbA1c and elevated fasting TG.

RESULTS

As previously reported, improvement in HbA1c and fasting TG from baseline to 12 months on metreleptin were observed in the overall population (mean change -1.57 percentage points and median change -37.9%, respectively) and subgroups. For both HbA1c and TG, baseline levels were significant predictors of changes after metreleptin. After considering baseline characteristics such as disease type, age, sex, and baseline HbA1c, baseline insulin use was not found to be a significant predictor of HbA1c improvement following metreleptin initiation. Similar results were seen for TG levels, with the use of any lipid-lowering medications at baseline not found to be a significant predictor of reductions in fasting TG levels.

CONCLUSIONS

Patients treated with metreleptin experienced statistically significant improvement in metabolic markers of glycemic and hypertriglyceridemic control-e.g. HbA1c and triglyceride levels-across various subgroups after controlling for baseline characteristics and concomitant medication usage.

Evaluation of the feasibility and accuracy of remote mobile app-based self-reported atrial fibrillation risk factor assessment in patients with atrial fibrillation: TeleCheck-AF results

Background

Previously, we introduced the TeleCheck-AF approach, which is an on-demand mobile health (mHealth) infrastructure incorporating mobile app-based heart rate and rhythm monitoring as well as mobile app-based self-reported atrial fibrillation (AF) risk factor assessment to allow comprehensive remote AF management through teleconsultation. Herein, we evaluated the feasibility and accuracy of remote mobile app-based self-reported AF risk factor assessment in AF patients.

Methods

In our University Medical Center, 545 patients were managed within the TeleCheck-AF project by an on-demand heart rate and rhythm mHealth infrastructure through teleconsultation. Patients were asked to fill in a short mobile app-based 10-item questionnaire related to AF risk factors. A reminder to complete the questionnaire automatically popped-up after the following four heart rate and rhythm recordings. Furthermore, patient's medical history was retrieved from the electronic health records (EHRs).

Results

Out of 545 patients, 542 (99.4%) patients (217 female, age 67 (59–72) years) completed the mobile app-based 10-item questionnaire and were included in this analysis. The number of patients with diabetes mellitus was similar in the EHRs and mobile app-based questionnaire (both 11.3%, p=1.000). There was no significant difference in the number of patients who had a medical history of transient ischemic attack (TIA)/cerebrovascular accident (CVA) and artery disease (coronary artery disease and peripheral artery disease) in the EHRs and mobile app-based questionnaire (11.4% vs 12.2%, p=0.608 and 14.8% vs 13.3%, p=0.366, respectively). Heart failure was more frequently reported in the mobile app-based questionnaire compared to the EHRs (33.4% vs 14.0%, p&lt;0.001). A total of 260 (48.0%) patients had a diagnosis of hypertension verified in EHRs and only 239 (44.1%) patients reported hypertension in the mobile app-based questionnaire (p=0.044). There was no significant difference in number of patients with CHA2DS2-VASc-score ≥2 between the EHRs and mobile app-based questionnaire (64.2% vs 66.1%, p=0.275). The accuracy of mobile app-based assessment of diabetes mellitus was 85.4%, of TIA/CVA 78.9%, of artery disease 60.9%, of heart failure 78.8%, and of hypertension 89.3%.

Conclusion

Patient self-reported AF risk factors by a remote mobile app-based assessment is feasible and may be useful for future digital trials and comprehensive remote AF management through teleconsultation.

Funding Acknowledgement

Type of funding sources: None.

Effect of Leptin Therapy on Survival in Generalized and Partial Lipodystrophy: A Matched Cohort Analysis

CONTEXT

Data quantifying the impact of metreleptin therapy on survival in non-human immunodeficiency virus (HIV)-related generalized lipodystrophy (GL) and partial lipodystrophy (PL) are unavailable.

OBJECTIVE

This study aimed to estimate the treatment effect of metreleptin on survival in patients with GL and PL.

DESIGN/SETTING/PATIENTS

Demographic and clinical characteristics were used to match metreleptin-treated and metreleptin-naïve patients with GL and PL. Differences in mortality risk were estimated between matched cohorts of metreleptin-treated and metreleptin-naïve patient cohorts using Cox proportional hazard models. Sensitivity analyses assessed the impact of study assumptions and the robustness of results.

OUTCOME MEASURES

This study assessed time-to-mortality and risk of mortality.

RESULTS

The analysis evaluated 103 metreleptin-naïve patients with characteristics matched to 103 metreleptin-treated patients at treatment initiation. Even after matching, some metabolic and organ abnormalities were more prevalent in the metreleptin-treated cohort due to bias toward treating more severely affected patients. A Cox proportional hazards model associated metreleptin therapy with an estimated 65% decrease in mortality risk (hazard ratio [HR] 0.348, 95% confidence interval (CI): 0.134-0.900; P = 0.029) even though the actual number of events were relatively small. Results were robust across a broad range of alternate methodological assumptions. Kaplan-Meier estimates of time-to-mortality for the metreleptin-treated and the matched metreleptin-naïve cohorts were comparable.

CONCLUSIONS

Metreleptin therapy was associated with a reduction in mortality risk in patients with lipodystrophy syndromes despite greater disease severity in treated patients, supporting the view that metreleptin can have a positive disease-modifying impact. Confirmatory studies in additional real-world and clinical datasets are warranted.

Safety and acute clinical outcomes of atrial fibrillation catheter ablation in octogenarians: a multicentre evaluation with a matched younger cohort

Funding Acknowledgements

Type of funding sources: None.

OnBehalf

Sven Knecht and the International Octogenarian AF ablation group

Background

Octogenarians are a fast-growing demographic with a high burden of atrial fibrillation (AF). There are limited data on procedural safety and acute outcomes of catheter ablation (CA) for AF in this group.

Purpose

Investigation of complications & outcomes in octogenarians undergoing CA for AF.

Methods

Data on all octogenarian patients who underwent AF ablation at nine European cardiology centres between 2013 and 2019 were retrospectively analysed and matched with control patients aged &lt;80 years.  The characteristics used for matching were type of AF, type of procedure (de novo or redo), & the year of procedure.

Results

216 octogenarians (81.9 ± 1.9 years; 52.8% females) underwent an AF ablation procedure, and were matched with 216 patients aged &lt;80 years (62.4 ± 9.5 years, 34.7% females), p &lt;0.001 for both. The proportion of paroxysmal and persistent AF was 43.5% & 56.5% respectively in both groups, and 79.3% of the procedures were de novo. RF ablation made up 75.4% & 75.9% (p = 0.90) procedures in octogenarians and controls respectively.  17 complications occurred in 14 (7.9%) octogenarian patients and 11 in 11 (5.1%) patients in the younger matched cohort (p = 0.07). There were 4.2% & 1.9% major complications (p= 0.17) and 3.7% & 3.2% minor complications (p= 0.77) in the octogenarian & younger cohorts respectively. Complications in octogenarians consisted of groin complications (n = 6), pneumonia (n = 3), pericardial effusion (n = 2), phrenic nerve injury (n = 2), pulmonary oedema (n = 1), gastroparesis (n = 1), stroke (n = 1). Acute procedural success rates were 99.1% & 99.5% (p = 0.62) The complication rates were similar for RF; 6.0% vs 5.4% (p = 0.79) and Cryoballoon; 14.0% vs 4.1% (p = 0.09) in both octogenarians and younger cohort respectively.

Conclusion

In spite of significantly higher overall risk profile of octogenarians undergoing AF ablation, there is no difference in acute procedural success and complication rates as compared to younger patients Catheter ablation of AF in octogenerians Octogenarians n = 216 Matched Controls (aged &lt; 80yrs) n = 216 P value Age (yrs), mean (SD)s 81.9 (1.9) 62.4(9.5) &lt; 0.0001 Females, (%) 52.8 34.7 0.0002 CHA2DS2-VASc, mean (SD) 3.6 (1.2) 1.4 (1.3) &lt; 0.0001 Mean LA size, mm 42.8 ± 8.3mm 45.8 ± 16.2 0.062 Impaired LV function, (%) 23.7 17.9 0.206 IHD, (%) 20.7 5.9 &lt; 0.0001 Procedural time (mins), mean (sd) 150.6 (69.7) 148.9 (64.4) 0.914 All complications, n (%) 17 (7.9) 11 (5.1) 0.073

The TeleCheck-AF project on remote app-based management of atrial fibrillation during the COVID-19 pandemic: Patient experiences

Funding Acknowledgements

OnBehalf

Aims

Methods

Results

Conclusions

Ablation Index-guided 50W ablation for left atrial posterior wall isolation compared with lower powers: feasibility and lesion level analysis

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Groupe de Rythmologie de la Société Française de Rythmologie

Background 

Posterior Wall Isolation (PWI) is increasingly performed for Atrial Fibrillation (AF). The use of Ablation Index (AI)-guided 50W ablation for PWI has not been described, nor the interplay between ablation parameters at this power when compared to lower powers. 

Methods 

40 consecutive AF patients (26 males, 65.5 ± 10.0 years. 95% non-paroxysmal AF) underwent PWI following pulmonary vein isolation. A roof line and floor line were created with point-by-point ablation, targeting a contact force (CF) of 10-30g, AI 550-600 on the roof and 400-450 on the floor, and inter-tag distance of &lt;6mm. 35-40W powers were used for the first 20 patients, and 50W used for the next 20. Generator impedance was monitored in real time for each lesion. Ablation inside the box was delivered in case of failure of first pass isolation (FPI). All VisiTags (n = 959) were analyzed retrospectively. 

Results 

PWI was successful in 19(95%) of the 35-40W group and in all 20 patients in the 50W group, with FPI seen in 8(40%) and 10(50%) respectively, p = 0.53. The mean CF and number of RF applications on the roof. floor and inside the box were similar between the two groups. Ablation time per lesion (10.4 [8.8-12.5]sec) and total ablation time per patient (3.84[3.34-4.66] min) were shorter in the 50W group as compared to 35-40W (13.0 [11.6-16.2] sec and 5.86 [4.23-7.73] min respectively), p &lt; 0.005. The mean AI and Impedance Drop were larger in the 50W group (Table). There was no steam pop observed in any of the 959 radiofrequency applications. 

Conclusion 

Ablation Index guided 50W ablation has a very high success rate for posterior wall isolation with shorter ablation times and higher impedance drop compared to conventional powers. Steam pops may be avoidable by targeting CF &lt; 30g, and by monitoring impedance in real-time. 50W Group(N = 458) 35-40W Group(N = 501) p-value Number of lesions (s, IQR)Roof lineFloor lineAdditional ablation inside box 21.5 [19.5-26.3]7.0 [5.8-9.0]13.0 [10.8-14.3]6.0 [6.0-6.8] 24.0 [20.8-29.5]8.0 [6.0-10.0]12.5 [10.8-14.0]5.5 [2.8-9.0] 0.330.180.850.59 Ablation Time per lesion (s, IQR)Roof lineFloor lineAdditional ablation inside box 10.4 [8.8-12.5]13.0 [10.9-16.0]9.9 [8.7-11.4]8.1 [6.9-9.0] 13.0 [11.6-16.2]14.5 [12.4-19.0]12.7 [11.4-15.9]11.8 [10.6-14.0] &lt;0.005&lt;0.005&lt;0.005&lt;0.005 Total RF Time (min, IQR)Roof lineFloor lineAdditional ablation inside box 3.84 [3.34-4.66]1.54 [1.15-1.90]2.06 [1.68-2.54]0.79 [0.65-1.07] 5.86 [4.23-7.73]1.98 [1.62-2.59]2.78 [2.28-3.25]1.07 [0.59-1.42] &lt; 0.0050.0190.0090.50 Impedance Drop (ohms, IQR)Roof lineFloor lineAdditional ablation inside box 7.4 [5.2-10.3]8.7 [6.1-11.3]6.9 [5.0-10.1]7.1 [5.4-9.8] 6.9 [4.8-9.7]7.5 [5.1-10.0]6.0 [4.2-8.3]8.3 [5.8-10.9] 0.0070.04&lt; 0.0050.17 Contact Force (g, IQR)Roof lineFloor lineAdditional ablation inside box 21.1 [14.5-30.3]23.9 [17.8-32.7]19.2 [13.2-25.3]25.5 [18.5-36.9] 21.2 [14.9-28.1]24.3 [17.2-30.3]19.0 [14.1-25.0]23.1 [16.9-31.7] 0.560.450.870.21 Ablation Index (IQR)Roof lineFloor lineAdditional ablation inside box 471 [441-519]560 [509-571]453 [436-475]461 [430-488] 461 [434-493]502 [466-541]446 [426-464]455 [434-478] &lt; 0.005&lt; 0.005&lt; 0.0050.59 Lesion level analysis for Posterior Wall Isolation