Produção Nacional
Revisado por pares
Long-term outcome after Cardiac Resynchronization Therapy: A nationwide database
2012; Elsevier BV; Volume: 155; Issue: 3 Linguagem: Inglês
10.1016/j.ijcard.2011.12.083
ISSN1874-1754
AutoresCláudia Drumond Guimarães Abreu, Regina Maria Aquino Xavier, Jamil S. Nascimento, Antônio Luiz Pinho Ribeiro,
Tópico(s)Cardiac Arrhythmias and Treatments
ResumoHeart failure (HF) is a complex clinical syndrome that represents a growing public health problem [1Mathers C. Fat D.M. Boerma J.T. World Health Organization The global burden of disease: 2004 update. World Health Organization, Geneva, Switzerland2008Crossref Scopus (29) Google Scholar, 2Lloyd-Jones D, Adams RJ, Brown TM, et al. Heart disease and stroke statistics--2010 update: a report from the American Heart Association. Circulation 2010;121:e46–215.Google Scholar]. Cardiac resynchronization therapy (CRT) is one of the surgical procedures proposed to HF treatment. Nevertheless, although its efficacy – both in isolated therapy (CRT-P) and combined with cardiac defibrillators (CRT-D) – has been shown in randomized clinical trials [3Cazeau S. Leclercq C. Lavergne T. et al.Effects of multisite biventricular pacing in patients with heart failure and intraventricular conduction delay.N Engl J Med. 2001; 344: 873-880Crossref PubMed Scopus (2433) Google Scholar, 4Stellbrink C. Breithardt O.A. Franke A. et al.Impact of cardiac resynchronization therapy using hemodynamically optimized pacing on left ventricular remodeling in patients with congestive heart failure and ventricular conduction disturbances.J Am Coll Cardiol. 2001; 38: 1957-1965Abstract Full Text Full Text PDF PubMed Scopus (372) Google Scholar, 5Young J.B. Abraham W.T. Smith A.L. et al.Combined cardiac resynchronization and implantable cardioversion defibrillation in advanced chronic heart failure: the MIRACLE ICD Trial.JAMA. 2003; 289: 2685-2694Crossref PubMed Scopus (1382) Google Scholar, 6Bristow M.R. Saxon L.A. Boehmer J. et al.Cardiac resynchronization therapy with or without an implantable defibrillator in advanced chronic heart failure.N Engl J Med. 2004; 350: 2140-2150Crossref PubMed Scopus (4523) Google Scholar, 7Cleland J.G. Daubert J.C. Erdmann E. et al.The effect of cardiac resynchronization on morbidity and mortality in heart failure.N Engl J Med. 2005; 352: 1539-1549Crossref PubMed Scopus (4916) Google Scholar, 8Linde C. Abraham W.T. Gold M.R. St John Sutton M. Ghio S. Daubert C. Randomized trial of cardiac resynchronization in mildly symptomatic heart failure patients and in asymptomatic patients with left ventricular dysfunction and previous heart failure symptoms.J Am Coll Cardiol. 2008; 52: 1834-1843Abstract Full Text Full Text PDF PubMed Scopus (853) Google Scholar] and recently demonstrated for patients with less functional impairment [9Daubert C. Gold M.R. Abraham W.T. et al.Prevention of disease progression by cardiac resynchronization therapy in patients with asymptomatic or mildly symptomatic left ventricular dysfunction: insights from the European cohort of the REVERSE (Resynchronization Reverses Remodeling in Systolic Left Ventricular Dysfunction) trial.J Am Coll Cardiol. 2009; 54: 1837-1846Abstract Full Text Full Text PDF PubMed Scopus (288) Google Scholar, 10Tang A.S. Wells G.A. Talajic M. et al.Cardiac-resynchronization therapy for mild-to-moderate heart failure.N Engl J Med. 2010; 363: 2385-2395Crossref PubMed Scopus (1252) Google Scholar], its effectiveness in the real world should be better evaluated. In middle income countries, such as Brazil, the effectiveness of CRT in the mid- and long run is unknown. The public expenses with the procedure are high in the country, despite the lack of detailed information on the final outcome of patients submitted to the implant. This scenario represents a major challenge for healthcare managers who aim at administrative efficiency and real improvement in quality of life and survival of patients. So the present study analyzed, in the period from 2002 to 2007, the effectiveness of CRT in the Brazilian public services managed and financed by the Unified Health System (SUS, acronym in Portuguese), who assists approximately 80% of the population [[11]Ministry of Health of Brazil DATASUS.http://www.datasus.gov.brDate: 2010Google Scholar]. The project was approved by the Institutional Review Board of the Universidade Federal de Minas Gerais with agreement of the manager of the Ministry of Health in country. The method proposed for the study based on the linkage of records from official health databases. The Hospital Information System of the Unified Health System (SIH, acronym in Portuguese) and Mortality Information System (SIM, acronym in Portuguese), two large databases available in the country, were selected. The RecLink III (RL3) software, a public domain tool, version 3.1, was used to apply the probabilistic linkage [[12]Camargo Jr., K.R. Coeli C.M. Reclink: an application for database linkage implementing the probabilistic record linkage method.Cad Saude Publica. 2000; 16: 439-447Crossref PubMed Google Scholar]. Pilot studies were conducted and processing details have been described in a previous study conducted by the same group of researchers [[13]Migowski A. Chaves R.B. Coeli C.M. et al.Accuracy of probabilistic record linkage in the assessment of high-complexity cardiology procedures.Rev Saude Publica. 2011; 45: 269-275Crossref PubMed Scopus (15) Google Scholar]. The date of the first implant identified in the period defined for the study, was considered as the beginning of observation for each individual (T0). The limit entry date for new cases was the last day of 2007, and the final date of follow-up was the last date with information available at the SIM (December 31, 2008). So, a "National Database of Multisite Pacemaker" consisting of 3526 patients was established from January 1st, 2002 to December 31st, 2007. The Statistical Package for Social Sciences — SPSS, version 18.0, was used for all analyses. The nonparametric Kaplan-Meier estimator was used to calculate the survival functions, and T0 up to date of death was considered the endpoint. The log-rank test was employed to compare the survival functions for co-variables. The Cox proportional hazards model was used and hazard-ratios (HR) and their respective 95% confidence intervals (CI) were calculated. The mean follow-up was 2.8 years (maximum 7 years) and the baseline characteristics of the final cohort are described in Table 1. After linkage between SIH and SIM databases, a total of 1332 deaths referred primarily to cardiac causes were identified, fifty of them occurred during the same admission of the index procedure.Table 1Baseline characteristics of the study population.VariablesPatients (N=3526)Age, mean±SD, (years)59.8±13.3Males, N (%)2316 (66)Leading causes of hospitalization, N (%) Total atrioventricular block660 (18.7) Not specified heart failure657 (18.6) Dilated cardiomyopathy608 (17.2) Ischemic cardiomyopathy475 (13.5) Ventricular tachycardia322 (9.1)Types of CRT devices, N (%) CRT-P2811 (79.7) CRT-D715 (20.3)Implant technique, N (%) Endocardiac (transvenous)1701 (83.4) Epicardic (minithoracotomy)584 (16.6)Admission by state, N (%) São Paulo1883 (53.4) Minas Gerais209 (5.9) Bahia173 (4.9) Others states1261 (35.8)Median length of hospital stay, (IQR),(days)4.0 (2.0–9.0)Juridical nature of hospital, N (%) Charity Hospital1472 (41.7) SUS Hospital1067 (29.7) Contracted Hospital697 (19.8) University Hospital310 (8.8)Nature of hospitalization, N (%) Urgency / Emergency2296 (65.1) Elective1230 (34.9)SD: standard deviation; CRT-P: cardiac resynchronization therapy pacemakers; CRT-D: cardiac resynchronization therapy defibrillators; IQR: interquartile range; SUS: unified health system Open table in a new tab SD: standard deviation; CRT-P: cardiac resynchronization therapy pacemakers; CRT-D: cardiac resynchronization therapy defibrillators; IQR: interquartile range; SUS: unified health system The overall survival of patients submitted to CRT in the country was 80.1% (95% CI 79.4–80.8) in one year and 55.6% (95% CI 54.6–56.6) in 5 years, whereas the median overall survival was 30.3 months (IQR, 16.1–50.9). When analyzed separately, CRT-P (N=2811) was 87% and 55.4% in 1 and 5 years, and CRT-D (N=715) was 83.4% and 52.3%. A statistically significant difference in the incidence of events for the variable sex (p<0.0001) was demonstrated. Furthermore, in univariate analysis, improved survival – albeit within limits – was observed in the cohort studied, from 2002 throughout 2007 (p=0.055) (Fig. 1). There was no statistically significant difference in the survival curves when analyzing age (log-rank: p=0.230), CRT-P or CRT-D (log-rank: p=0.237) and endocardiac or epicardic implant technique (log-rank: p=0.321). The variables included in the final Cox regression model are listed in Table 2.Table 2Cox proportional hazard regression analysis (final model).Covariatebs.e.P-valueExp(b)95% CI for Exp(b)Sex0.3480.0610.0001.4161.257–1.596Age (in decades)0.0430.0210.0381.0441.002–1.088Year of Implant (2002)0.046Year of Implant (2003)0.1930.0660.0031.2131.066–1.381Year of Implant (2004)0.0630.0590.2851.0650.949–1.197Year of Implant (2005)−0.0660.0580.2550.9360.836–1.049Year of Implant (2006)−0.0510.0600.3930.9500.844–1.069Year of Implant (2007)−0.0370.0640.5610.9630.849–1.09395% CI, 95% confidence interval; b, logistic regression coefficient; P, significance level; s.e., standard error of logistic regression coefficient. Open table in a new tab 95% CI, 95% confidence interval; b, logistic regression coefficient; P, significance level; s.e., standard error of logistic regression coefficient. This is the largest observational study evaluating the effectiveness of CRT performed in a public health system, and applying the methodology of probabilistic linkage to official healthcare databases. Our results demonstrated a favorable outcome of patients submitted to CRT, considering improved survival throughout the years studied and overall survival, in one and 5 years. Despite smaller percentages, especially in the first year of implant, as compared to those obtained in the randomized clinical trials [3Cazeau S. Leclercq C. Lavergne T. et al.Effects of multisite biventricular pacing in patients with heart failure and intraventricular conduction delay.N Engl J Med. 2001; 344: 873-880Crossref PubMed Scopus (2433) Google Scholar, 4Stellbrink C. Breithardt O.A. Franke A. et al.Impact of cardiac resynchronization therapy using hemodynamically optimized pacing on left ventricular remodeling in patients with congestive heart failure and ventricular conduction disturbances.J Am Coll Cardiol. 2001; 38: 1957-1965Abstract Full Text Full Text PDF PubMed Scopus (372) Google Scholar] and in the observational studies [14Auricchio A. Metra M. Gasparini M. et al.Long-term survival of patients with heart failure and ventricular conduction delay treated with cardiac resynchronization therapy.Am J Cardiol. 2007; 99: 232-238Abstract Full Text Full Text PDF PubMed Scopus (83) Google Scholar, 15Saxon L.A. Hayes D.L. Gilliam F.R. et al.Long-term outcome after ICD and CRT implantation and influence of remote device follow-up: the ALTITUDE survival study.Circulation. 2010; 122: 2359-2367Crossref PubMed Scopus (368) Google Scholar], the results observed showed better quality of care delivered to patients with advanced HF by the public health system. This improved outcome along the years seems to result from measures adopted by public managers responsible for high-complexity cardiovascular procedures in the country. The regulation of the procedure by the Ministry of Health, as from 2004, allowed setting qualified centers, credentialed according to technical criteria and populational parameters [16Brazil, Health Ministry, PT GM/MS No. 1169 of 15/06/2004 Establishes the National Policy for High Cardiovascular Complexity.Official Gazette, Section 1, N°. 115, Thursday. June 17 2004http://www.in.gov.brGoogle Scholar, 17Brazil, Health Ministry, PT SAS/MS nº 210, 15/06/2004 Establishes standards for the Reference's Centers.in: Official Gazette, Section 1, N°.117, Monday. June 21 2004: 43-80http://www.in.gov.brGoogle Scholar]. Such process certainly contributed to improved overall survival in the study, by providing incentives in terms of technical training of the professionals involved, which resulted in more strict indications for the procedures, less of pre- and postoperative complications, optimization of generator programming, together with technological improvement of the devices and equipment offered by specialized industries. In this series no difference in survival between the CRT-P and the CRT-D was observed. Although our observation is in agreement with other studies,[[18]Zareba W. Klein H. Cygankiewicz I. et al.MADIT-CRT Investigators. Effectiveness of Cardiac Resynchronization Therapy by QRS Morphology in the Multicenter Automatic Defibrillator Implantation Trial-Cardiac Resynchronization Therapy (MADIT-CRT).Circulation. 2011; 23: 1061-1072Crossref Scopus (577) Google Scholar] a more comprehensive analysis of this finding was hindered due to absence of clinical variables in the listed databases, especially the SIH employed in the study, acknowledged as a primarily administrative database. This fact contributed to limitations of the study, since the lack of specific clinical data in the listed databases, such as the NYHA functional class, LVEF, presence or not of atrial fibrillation, drugs on use, QRS width and co-morbid conditions, hindered adjustment of the results for these variables. Therefore, it was concluded that effectiveness of the CRT verified in the real world is similar to that of the large clinical trials. Furthermore, throughout the years assessed, there was improvement in survival of the patients submitted to implant in the public health system. In this context, economic analyses are still needed to evaluate cost-effectiveness of the procedure in middle-income countries.
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