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Print version ISSN 0034-7094
Rev. Bras. Anestesiol. vol.55 no.1 Campinas Jan./Feb. 2005
The validity of the electrocardiogram accomplishment in the elderly surgical patient preoperative evaluation*
Validez de la rutina de realización del electrocardiograma en la evaluación pre-operatoria de ancianos
Flávia Salles de Souza, M.D.I; José Ricardo Pinotti Pedro, M.D.I; Joaquim Edson Vieira, TSA, M.D.II; Arthur Vitor Rosenti Segurado, M.D.I; Marcos Paulo Ferreira Botelho, M.D.III; Lígia Andrade da Silva Telles Mathias, TSA, M.D.IV
IMédico Assistente, Serviço
de Anestesiologia da Irmandade Santa Casa de Misericórdia de São Paulo
IICoordenador do Centro para Desenvolvimento da Educação Médica, CEDEM da Faculdade de Medicina da Universidade de São Paulo
IIIGraduando do 6º ano da Faculdade de Ciências Médicas da Santa Casa de São Paulo
IVDiretora do Serviço e Disciplina de Anestesia, Irmandade Santa Casa de Misericórdia de São Paulo e Faculdade de Ciências Médicas da Santa Casa de São Paulo; Responsável pelo Centro de Ensino e Treinamento, CET/SBA, ISCMSP
BACKGROUND AND OBJECTIVES: Because of
medical progress, life expectancy has been prolonged and the elderly population
submitted to surgical procedures has been growing. Besides age-related cardiovascular
changes, the prevalence of diseases, such as systemic hypertension, affect cardiovascular
reserve and increase morbidity, mortality and perioperative outcomes. Electrocardiogram
is useful in diagnosing previous myocardial infarction and arrhythmias. In the
preoperative evaluation of these patients, ECG usefulness is a controversial
subject. This study aimed at retrospectively evaluating the validity of preoperative
ECG in elderly patients.
METHODS: Retropective analysis of 481 patient records over 60 years old, submitted to different surgical procedures. Data were collected for description of the studied group; evaluation of most frequent electrocardiography abnormalities; comparative analysis between patients with normal and abnormal ECG related to age, ASA physical status, presence of cardiac disease intra and postoperative complications. Patients without cardiovascular disease (CVD) and physical status ASA I were separately analyzed.
RESULTS: There were 481 patients, 287 of them with preoperative ECG and from those, 88,8% had abnormalities, being the most frequent ventricular repolarization changes.There was not influence of the parameters on the frequency of abnormal ECG. The abnormalitees of the ECG, especially those secondary to ischemia were related with intraoperative complications in all study groups.
CONCLUSIONS: This study has shown that electrocardiogram is a valid routine for preoperative evaluation of elderly patients.
Key words: ANESTHESIA, Elderly; PREOPERATIVE EVALUATION; PREOPERATIVE TESTS: electrocardiography
JUSTIFICATIVA Y OBJETIVOS: Con los avances
médicos y el aumento de la expectativa de vida, la población de ancianos
sometidos a procedimientos quirúrgicos viene aumentando. El paciente de
edad tiene mayor morbiletalidad cardiaca peri-operatoria que el paciente joven,
también cuando asintomático. El electrocardiograma (ECG) ha sido pedido
en el período pre-operatorio en la tentativa de reducir la morbiletalidad
intra-operatoria, sin embargo su eficacia es controversa. No hay acuerdo en
la literatura a respecto de la indicación del ECG en pacientes ancianos
en el período pre-operatorio, lo que motivó la realización de
este estudio. El objetivo fue verificar retrospectivamente la validez de la
rutina de realización del ECG en el período pre-operatorio en una
población de pacientes ancianos quirúrgicos.
MÉTODO: Análisis retrospectivo de prontuarios de pacientes a partir de 60 años, sometidos a cirugías diversas, durante el período de 6 meses. Los datos fueron colectados para análisis descriptivo de la población estudiada; evaluación de la incidencia y de los tipos más frecuentes de anormalidad de los ECG; análisis comparativo de los pacientes con ECG normal y alterado con relación a las diversas variables - edad, perfil de edad, estado físico, presencia de enfermedad cardiovascular (DCV), complicaciones intra (CIO) y post-operatorias (CPO).También fueron evaluados los pacientes sin DCV y aquéllos con estado físico ASA I con relación a las CIO y CPO, según los tipos de alteraciones del ECG y edad del paciente.
RESULTADOS: Fueron analizados los prontuarios de 481 pacientes, de los cuales 287 contenían ECG y de éstos, 88,8% presentaban anormalidades, siendo más frecuente, la alteración de la repolarización ventricular. No fue observada influencia de las variables estudiadas sobre la incidencia de ECG alterados. La incidencia de alteraciones del ECG aumentó con el avance de la edad en todos pacientes estudiados. Con el avance de la edad también ocurrió aumento de la incidencia de pacientes con ECG alterados asociados con complicaciones intra-operatorias. Las anormalidades electrocardiográficas fueron relevantes con relación a la incidencia de complicaciones intra-operatorias en todos los grupos estudiados, principalmente las alteraciones secundarias a la isquemia.
CONCLUSIONES: Este estudio mostró que, para la población quirúrgica anciana estudiada, es válida la rutina de realización del electrocardiograma como parte de la evaluación pre-operatoria.
Life expectancy has increased in the last 100 years and medical progresses seem to be the major contributing factor. More than half of elderly people will be submitted to at least one surgical procedure during life and anesthesiologists have to be prepared to evaluate and understand this increasing number of patients 1.
For the cardiovascular system, aging is related to a wide variety of structural and functional changes in heart and vessels. In addition to age-related physiological changes, there is increased prevalence of underlying cardiovascular diseases (systemic hypertension, atherosclerosis, acute myocardial infarction, congestive heart failure) which limit even further the functioning of this system 2,3
Major preoperative and preanesthetic evaluation objective is always to decrease perioperative morbidity-mortality, regardless of patients' age. In this sense, lab tests are being currently indicated as priority according to history and/or physical evaluation findings 4.
Preoperative ECG is routinely indicated in the attempt to identify cardiovascular diseases and decrease intraoperative morbidity-mortality, however, its influence on pre and intraoperative approaches to prevent cardiovascular complications is controversial 5-7.
Several authors have described increased ECG changes with age 8-11.
It is known that silent myocardial ischemia (SMI) is more frequent in the elderly 12 and that recent infarction is a strong predictor for increased perioperative cardiovascular risk 13.
However, there are still divergences in the literature about the accuracy of preoperative ECG in predicting perioperative cardiovascular complications in elderly patients and, as a consequence, about its routine indication for this group of patients 10,12,14-16.
This study aimed at evaluating the usefulness of routine preoperative ECG in a population of elderly surgical patients.
After the approval of the Research Ethics Committee, Hospital Central, Irmandade da Santa Casa de Misericórdia, São Paulo, this retrospective study consisted of the evaluation of elderly patients records (60 years or beyond) in the period April 1 to September 30, 2000. Patients were submitted to different surgical procedures under anesthesia, with preoperative ECG performed at admission or in outpatient regimen until 6 months before admission, with report of a cardiologist or clinician working for the institution.
Data collected were: gender, age, physical status (ASA), presence of signs or symptoms of cardiovascular disease or other related diseases, electrocardiogram, type of surgery and anesthetic technique, intraoperative hemodynamic complications not related to surgical adverse effects (heart rate or blood pressure increase/decrease above 20% of baseline and arrhythmias), and postoperative complications.
Data were evaluated in the following sequence:
1. Incidence of ECG performed in the conditions established by this study;
2. Incidence of normal and abnormal ECG with regard to variables: age, age bracket (60-69, 70-79 and > 80 years of age), physical status, presence of cardiovascular disease, intra and postoperative complications. Incidence of abnormal ECG associated to intra and postoperative complications according to age distribution, types of electrocardiography changes and incidence of intra and postoperative complications related to observed abnormalities;
3. Evaluation of patients with no cardiovascular disease and ASA I to: check the incidence of abnormal ECG according to age distribution and the incidence of associated intra and postoperative complications; check the types of electrocardiography changes and the incidence of intra and postoperative complications related to observed changes.
Results were submitted to descriptive analysis. Non-paired Student's t test was used to compare age results. Chi-square test (c2) was used to compare results of remaining variables. P < 0.05 was considered statistically significant. Tests used are part of the statistical suite Sigma Stat for Windows, version 2.03, SPSS Inc.
From 481 evaluated files, 194 were excluded for being patients submitted to surgery without ECG or with ECG not complying with our protocol. Total number of patients included was 287, of whom 255 had abnormal ECG (88.85%).
Mean age (standard deviations) of patients with normal and abnormal ECG were respectively 74.2 (7.1) and 73.5 (8.2) years without statistical difference among groups (non-paired t test - p = 0.643). There were also no significant differences in gender distribution with majority of males in both groups (c2 - p = 0.544).
There were no significant differences among groups in normal and abnormal ECG and physical status (ASA) (c2), with most patients with abnormal ECG, regardless of physical status (Table I).
When normal and abnormal ECG patients were compared for the presence of symptomatic cardiovascular disease (SCD) and intraoperative (IOC) and postoperative (POC) complications there were no statistically significant differences among groups, that is, the number of patients with or without SCD; with or without IOC, with or without POC was similar in both normal and abnormal ECG groups (Table II).
Figure 1 shows age bracket distribution and total number of patients with normal and abnormal ECG. There have been statistical differences in age bracket, and in the number of normal and abnormal ECG (c2; p = 0.0006).
Table III shows results of age distribution of the total number of patients with abnormal ECG with or without IOC and POC and statistical analysis result (c2). There has been significant increase in IOC with increased age (p = 0.0146), what was not seen with POC (p = 0.0799).
Table IV shows abnormal ECG results, which were classified as: ventricular repolarization changes, cardiac rhythm changes (supraventricular and ventricular extra-systole, atrial fibrillation, sinusal tachycardia and bradycardia); changes secondary to ischemia (inactive zone, T wave inversion, ischemic zone); conduction blockades (1st degree and total atrioventricular block, right and left branches block and left anterior divisional block) and cardiac chambers overload (right and left atrial and right and left ventricular chambers). There were 97 ECG with more than one abnormality, sometimes three or even more, and these were jointly evaluated.
Table V shows types of electrocardiography changes and the incidence of intra and postoperative complications. Ten (66.6%) patients with changes secondary to ischemia, and 24 (36.4%) patients with ventricular repolarization changes had IOC. Mean ages and standard deviations of patients without CVD and with normal and abnormal ECG were similar (74 ± 7,2 and 73,6 ± 7,8 years, respectively).
Figure 2 shows age distribution of patients without CVD with normal and abnormal ECG. Statistical analysis was not possible due to the small number of patients with normal ECG in certain age brackets.
Table VI shows age distribution of total number of patients without CVD, with abnormal ECG, with and without IOC and POC. There has been significant IOC increase with increased age (c2; p = 0.0283). Statistical analysis was not possible due to the small number of postoperative complications in patients without CVD and abnormal ECG, but descriptive analysis has not shown uniform variation in the incidence of POC with increased age.
In terms of types of electrocardiography changes in patients without CVD and the incidence of intra and postoperative complications, it has been observed that 3 (60%) patients with changes secondary to ischemia and 13 (38.2%) patients with more than one change have presented IOC (Table VII).
Mean ages and standard deviations of ASA I patients with normal and abnormal ECG were similar (73.3 ± 6,5 and 73.4 ± 6.8 years, respectively).
Figure 3 shows age distribution of the total number of ASA I patients with normal and abnormal ECG. Statistical analysis was not possible due to the small number of patients with normal ECG in some age brackets, but descriptive analysis has shown an increased number of abnormal ECG with increased age.
Table VIII shows intra and postoperative hemodynamic complications of ASA I patients with normal and abnormal ECG. Statistical analysis was not possible due to the small number of intra and postoperative complications in ASA I patients with abnormal ECG, but descriptive analysis has shown increased incidence of IOC from 16.6% to 46.1% with increased age, what was not true for POC.
In studying types of electrocardiography complications found in ASA I patients and the incidence of changes secondary to ischemia, 2 (100%) had IOC and 1 (50%) had POC (Table IX).
In summary, figure 4 shows the incidence of abnormal ECG by age distribution for the three studied groups (total number of patients, patients without CVD and ASA I patients), and figure 5 and figure 6 show the incidence of hemodynamic IOC in patients with abnormal ECG and patients with changes secondary to ischemia, with ventricular repolarization changes and more than one electrocardiography change.
For being a historical cohort or retrospective cohort study, our study has suffered some limitations, since records, certificates and forms do not follow uniform criteria 17.
The analysis of all records with ECG has shown that 88.85% had abnormal results. Seymour (1993) 18 has found similar incidence of abnormal ECG (79%) in a group of surgical patients aged above 65 years.
Most patients in our study were physical status ASA II with symptomatic CVD, which is in line with the literature 10,19.
We have not found significant differences between groups with normal and abnormal ECG in physical status and presence of CVD, differently from other authors 8,9,11,19-21.
As opposed to what could be imagined, that is, patients with no CVD and/or ASA I patients would be the "youngest" from the elderly group studied, mean age of these patients was similar to the group as a whole. Within groups, patients with normal or abnormal ECG had also similar mean age. However, there has been increased incidence of electrocardiography abnormalities with increased age in all groups, in agreement with the literature 9-11. It is worth highlighting that the lowest incidence of abnormal ECG was 75% in ASA I patients, aged 60 to 69 years and reaching 100% in the same group but aged above 79 years.
Hemodynamic IOC of patients with abnormal ECG in the total group of patients, in CVD-free patients and in ASA I patients have increased with age, fact not observed with POC. This suggests a question: would patients with abnormal ECG without CVD and ASA I have IOC increase with age similar to the total group of patients (in which cardiovascular patients would be included), due to age-related physiological changes, regardless of complaints, signs and symptoms? Based on this hypothesis, shouldn't routine ECG be indicated to every elderly patient?
In all groups, patients with changes secondary to ischemia were those with the highest incidence of intraoperative complications, which is in line with the literature 22-26. Important data is that in CVD-free and ASA I patients these changes were not followed by clinical symptoms and the incidence of IOC was 60% and 100%, once more suggesting routine ECG.
In Brazil, Nascimento et al. (1998) 10 have conducted a prospective study to evaluate the presence and distribution of preoperative ECG changes, in ASA I and II patients with no CVD or CVD risk factor, divided by age bracket from 30 to > 70 years and have questioned routine preoperative ECG in CVD-free patients, but have recommended that common-sense and individual experience should prevail in the final decision.
Two publications in the international literature should be stressed because they have summarized available evidences about preoperative ECG: Munro et al. (1997) review 27 and ASA Task Force (TF) review 28.
Both reviews were limited to high quality scientific evidences on the value of routine preoperative tests for adult patients, in the period 1966 to 1996 and 1966 to 1999, respectively. In addition, ASA TF 28 has collected the opinion of specialists aiming at reaching a consensus and develop a practical consulting guide for preanesthetic evaluation.
Authors have identified 28 and 30 studies, respectively, on preoperative ECG, most of them retrospective, of which, according to them, only two were limited to elderly patients 27. The prevalence of electrocardiography changes has exponentially increased with age, with physical status worsening and cardiac risk factors. There has been no consensus on the lowest age for routine preoperative ECG, especially in patients without specific risks.
Munro et al. (1997) 27 have concluded that the doubt of the benefit of routine ECG would remain for a population of asymptomatic patients with higher risk of intraoperative complications, such as elderly patients. According to the authors, although there are high quality evidences that the incidence of abnormalities would increase with age, the primary question would be whether the percentage of unexpected abnormalities implying changes in management would increase with age and that there were not enough evidences to answer this question.
ASA TF 28 has concluded that age could not be the single indicator for ECG, but has also concluded that available scientific literature lacked sufficiently rigorous information on preanesthetic evaluation to allow recommendations that would not be ambiguous.
This study confirms the propositions of different studies, but especially by Munro et al. (1997) 27 and ASA TF 28, that it is impossible to conclude that routine ECG should be performed in all elderly patients, not even to define the lowest age for such. However, our study has shown that preoperative ECG might be clinically relevant for elderly patients until randomized clinical trials are conducted.
So, within the limitations of this retrospective study, we have concluded that for ISCMSP's elderly surgical patients, routine ECG as part of preoperative evaluation is a valid approach.
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Dra. Ligia Andrade da Silva Telles Mathias
Address: Alameda Campinas, 139/41
ZIP: 01404-000 City: São Paulo, Brazil
Submitted for publication May 25, 2004
Accepted for publication October 15, 2004
* Received from Centro de Ensino e Treinamento/SBA, Serviço de Anestesia da Irmandade Santa Casa de Misericórdia de São Paulo (ISCMSP), São Paulo, SP