IntroductionAlthough rare, the atrioesophageal fistula is one of the most feared complications in radiofrequency catheter ablation of atrial fibrillation due to the high risk of mortality.ObjectiveThis is a prospective controlled study, performed during regular radiofrequency catheter ablation of atrial fibrillation, to test whether esophageal displacement by handling the transesophageal echocardiography transducer could be used for esophageal protection.MethodsSeven hundred and four patients (158 F/546M [22.4%/77.6%]; 52.8±14 [17-84] years old), with mean EF of 0.66±0.8 and drug-refractory atrial fibrillation were submitted to hybrid radiofrequency catheter ablation (conventional pulmonary vein isolation plus AF-Nests and background tachycardia ablation) with displacement of the esophagus as far as possible from the radiofrequency target by transesophageal echocardiography transducer handling. The esophageal luminal temperature was monitored without and with displacement in 25 patients.ResultsThe mean esophageal displacement was 4 to 9.1cm (5.9±0.8 cm). In 680 of the 704 patients (96.6%), it was enough to allow complete and safe radiofrequency delivery (30W/40ºC/irrigated catheter or 50W/60ºC/8 mm catheter) without esophagus overlapping. The mean esophageal luminal temperature changes with versus without esophageal displacement were 0.11±0.13ºC versus 1.1±0.4ºC respectively, P<0.01. The radiofrequency had to be halted in 68% of the patients without esophageal displacement because of esophageal luminal temperature increase. There was no incidence of atrioesophageal fistula suspected or confirmed. Only two superficial bleeding caused by transesophageal echocardiography transducer insertion were observed.ConclusionMechanical esophageal displacement by transesophageal echocardiography transducer during radiofrequency catheter ablation was able to prevent a rise in esophageal luminal temperature, helping to avoid esophageal thermal lesion. In most cases, the esophageal displacement was sufficient to allow safe radiofrequency application without esophagus overlapping, being a convenient alternative in reducing the risk of atrioesophageal fistula.
664 Background: X and T have demonstrated synergy in preclinical studies and survival benefits in metastatic BC. We aimed to determine whether the high efficacy of XT could translate into the neoadjuvant setting. Methods: Expression levels (mRNA) of 3 enzymes involved in X intratumoral activation and metabolism (thymidylate synthase [TS], thymidine phosphorylase [TP] and dihydropyrimidine dehydrogenase [DPD]), were determined in tumor biopsies before treatment and their relationship with clinical and pathological response analyzed using Fisher’s Exact Test. Pts with stage IIIA/IIIB LABC, adequate organ function and KPS ≥80 received 4 cycles of X 1250mg/m2 (1000mg/m2 for age >60) bid d1–14 and T 75mg/m2 d1 q3w followed by surgery, adjuvant AC q3w × 4 ± tamoxifen according to ER and PR status. The primary endpoint was pCR. Results: We enrolled 34 pts with LABC IIIA (44%)/IIIB (56%): median age 52y (30–72); KPS ≥90 (76%); median tumor size 6.8cm (2–20); N0 (20%), N1 (41%), N2/3 (35%); ER+PR-/p53+/HER2+ (23/24/28%). 128 cycles of X and T were administered (median 4, range 1–5). Main G3/G4 toxicities were: HFS 32%, diarrhea 15%, asthenia 9%, stomatitis 6% and neutropenia 71%. There were no treatment-related deaths. 2 pts were withdrawn prematurely due to adverse events. The overall response in 32 evaluable pts was 78%, including 5 CRs and 20 PRs. 6/29 pts evaluable for pathological response had pCR (20%), and 10 (33%) had ≤10mm residual tumor (3 microscopic RD) in breast. Nodal involvement after chemotherapy was N0 (33%), N1 (33%), N2 (27%), N3 (7%), and the rate of breast-conserving surgery was 17%. High TP/DPD ratio was associated with CR (p=0.037) and both high TP/DPD and low TS/DPD ratio appeared to correlate with residual tumor ≤10 mm (p=0.028). Conclusions: Neoadjuvant XT appears to be highly active. Safety was similar to that reported in anthracycline-pretreated pts but with less stomatitis. In this small sample, a high TP/DPD ratio appears to correlate with clinical response and a favorable enzymatic profile (high TP/DPD and low TS/DPD ratio) may predict for high pCR. A further prospective study is required to validate this hypothesis. No significant financial relationships to disclose.
Atrial fibrillation is the most prevalent arrhythmia in the world population. Despite the use of antiarrhythmics, it is difficult to control clinically, causing symptoms and mainly generating risk of a thromboembolic event. Since 1998, by means of radiofrequency ablation, the treatment of atrial fibrillation has completely changed, but together with this important evolution complications from this ablative treatment technique have also started. In addition to the pulmonary vein stenosis caused by the ablation and later corrected with the change in the technique, atrioesophageal fistulas appeared due to the application of radiofrequency in the posterior wall of the left atrium. This wall is very close (0.5 cm onaverage) to the esophagus, which facilitates the formation of the fistula that leads to the death of almost 100% of the affected patients, despite the various treatment measurements already developed. To avoid this serious complication, several authors have created techniques to protect the esophagus including its mechanical deviation to a region opposite to the radiofrequency application, taking advantage of its mobility and easiness of handling. The mechanical deviation of the esophagus has proven to be the simplest, cheapest and most efficient way to protect this organ from radiofrequency thermal damage during atrial fibrillation ablation.
A fibrilação atrial é a arritmia de maior prevalência na população mundial. Apesar do uso de antiarrítmicos, é de difícil controle clínico, ocasionando sintomas e principalmente gerando risco de um evento tromboembólico. A partir de 1998, por meio da ablação por radiofrequência, o tratamento da fibrilação atrial mudou completamente, porém junto a essa importante evolução também iniciaram as complicações advindas dessa técnica de tratamento ablativo. Além das estenoses das veias pulmonares causadas pela ablação e posteriormente corrigidas com a mudança da técnica, surgiram as fístulas átrio-esofágicas, devido à aplicação de radiofrequência na parede posterior do átrio esquerdo. Esta parede está bem próxima (0,5 cm em média) do esôfago, facilitando a formação da fístula que leva à morte quase 100% dos pacientes acometidos, apesar das diversas medidas de tratamento já desenvolvidas. Para evitar essa grave complicação, vários autores criaram técnicas para proteger o esôfago incluindo seu desvio mecânico para uma região oposta à da aplicação de radiofrequência, aproveitando a sua mobilidade e facilidadede abordagem. O desvio mecânico do esôfago tem se mostrado a forma mais simples, barata e eficiente de proteger esse órgão da lesão térmica da radiofrequência durante a ablação da fibrilação atrial.
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