Desenvolvimento de um escore de predição de resposta à terapia de ressincronização cardíaca em portadores de insuficiência cardíaca com fração de ejeção reduzida

Abstract

Cardiac resynchronization therapy (CRT) is a valid therapeutic option for heart failure (HF) patients with reduced ejection fraction (EF) and advanced functional class (FC). A retrospective study of 249 patients with HF who underwent biventricular pacemaker implantation associated or not with the cardioverter-defibrillator (ICD), from March 2006 to June 2015. The main objective was to develop a prediction score for CRT. The secondary objectives were to assess the impact of advanced age (> 65 years) on the clinical response and total and cardiovascular mortality; to assess the rate of acute and procedural complications in old patients; to describe the predictors factors associated with super response to CRT and long-term outcomes. The CRT response criteria were the improvement of FC ( 1 NYHA) and an increase in EF (>10%) and or decrease in left ventricular end-systolic diameter (LVESD >15%). The inclusion criteria were age > 18 years with optimized pharmacological therapy, New York Heart Association (NYHA) FC II/IV, QRS ≥120 ms, and EF ≤35%. The exclusion criteria were severe clinical disease with a life expectancy of < 1 year, symptomatic bradyarrhythmia with a narrow QRS complex, and recent myocardial infarct and cardiac surgery (< 6 months). Regarding the results, a logistic regression model was created to develop the score. From the analysis of the ROC curve, the cutoff point established was three, with a sensitivity of 60%, specificity of 80% and accuracy of 78%. The following variables were associated with a non-response to CRT: advanced renal dysfunction (stage 4-5), chronic obstructive pulmonary disease, atrial fibrillation and LVESD > 55 mm. The first two criteria received three points and the last two points, totaling 10 points and thus generating the RESYNC score. The response to CRT was not directly affected by age, with similar rates in old (> 65 years) and very old (> 75 years) patients. Cardiovascular mortality (p=0.73) and acute complications related to the procedure (p=ns) were also similar. Only total mortality was higher in the group > 75 years (p=0.03). 48 patients (19%) had a super response to CRT characterized by an increase in EF > 45% and/ or a decrease in LVESD > 30% six months after implantation. Multivariate analysis demonstrated that longer QRS duration (≥ 150 ms) and persistent right ventricular (RV) pacing were predictive of super response in this population. The cardiovascular mortality was not affected, but significant reductions in all-cause mortality and HF hospitalization rates in super-responders were observed. In conclusion, a RESYNC score ≤ 3 strongly suggests a positive response to CRT and should be useful for previous stratification of this population.