Non-pharmacological strategies to decrease anxiety in cardiac catheterization : integrative review

Objective: to identify and review the literature on non-pharmacological strategies used for reducing anxiety in patients receiving cardiac catheterization. Method: this study was an integrative literature review. The research was conducted using the databases LILACS, SciELO, Medline (through BVS and PubMed) and Scopus. Studies were analyzed according to their objective, method, instruments used for evaluating patients’ anxiety, and the results obtained. Results: the most used strategy for reducing anxiety in patients receiving cardiac catheterization was music therapy. However, no study identifying the most appropriate time for this intervention (before, during and/or after the procedure) was found. Other strategies identifi ed in this review were educational videos, massage, and palm therapy. Conclusion: the results found suggest that anxiety can be reduced using non-pharmacological strategies.


INTRODUCTION
Cardiovascular diseases are the main causes of morbidity and mortality worldwide.According to the American Heart Association (AHA), more than 2,150 Americans die of cardiovascular diseases each day, an average of one death every 40 seconds (1) .Projections suggest that by 2030, 40.8% of the American population will have some cardiovascular disease (1) .
In patients with ischemic heart disease, acute coronary syndrome is the most dramatic and frightening condition.The treatment for ischemic heart disease can be clinical (by using drugs), surgical (consisting of myocardial revascularization when cardiac catheterization indicates severe obstructive lesions) or vascular (angioplasty), depending on the patient's clinical situation and the degree of coronary artery obstruction (2) .Vascular procedures consist of percutaneous coronary intervention, and the method of accessing the heart and the coronary arteries is cardiac catheterization, which can be classified as primary (performed under emergency circumstances) and elective (performed without emergency circumstances) (3) .Coronary patients undergoing cardiac catheterization experience several unpleasant feelings, including anxiety, fear, discomfort and distress, anxiety being one of the most common (4)(5) .
Anxiety is characterized by symptoms such as palpitations, sweating, trembling or shaking, shortness of breath or smothering sensations, chest pain or discomfort, and/or stomach distress (6) .Anxiety activates the sympathetic nervous system leading to a variety of physiological responses (7) , such as tachycardia, sweating, increased oxygen consumption, hypertension, which can worsen the evolution of the patient.In addition, anxiety can have a negative effect on a patient's clinical outcomes such as treatment refusal and reduced tolerance to pain before, during and after the catheterization intervention.Nurses should implement effective non-pharmacological strategies in order to control patients' anxiety.
In this context, identifying non-pharmacological strategies to reduce anxiety in patients undergoing cardiac catheterization is very important to improve nursing care and to prevent the negative effects of anxiety on patients' clinical outcomes, such as tachycardia and chest pain.To our knowledge, no literature reviews to date have identified non-pharmacological strategies to reduce anxiety in this patient population despite the need for this type of research.
The objective of this review was to identify studies in the published literature about non-pharmacological strategies to reduce anxiety in patients who underwent cardiac catheterization.

METHOD
An integrative literature (8)(9) review was performed in the databases LILACS, SciELO, Medline (through BVS and PubMed) and Scopus.The controlled descriptors used for article search in the databases included "anxiety" and "cardiac catheterization" or "catheterization", and the keyword "apprehension".Inclusion criteria for article selection were studies published from 2002 to 2014, in Portuguese, English or Spanish.
Titles and abstracts were concurrently read and analyzed independently by two researchers, who compared and selected studies to be included.Studies that met all the inclusion criteria were fully read by both researchers.In addition, we included studies in the review that were cited by the articles originally selected but not identified in the databases when the controlled descriptors were used.The authors of the articles that could not be obtained in full through the databases were contacted electronically (Figure 1).Data from the selected articles were extracted by three researchers using an instrument validated by Ursi (10) , ensuring that all relevant data were extracted.The instrument includes The methodological quality of the articles was evaluated through the Jadad scale.This is an instrument with 3 items (randomization, blinding and an account of all patients), totaling 5 points, with a minimum possible score of 2 (11) .Studies with more than 3 points were considered of good quality.

RESULTS
The twelve selected studies were all clinical trials (two nonrandomized) and published in English (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23) , in 2012 (n=1), 2011 (n=2), 2009 (n=3), 2008 (n=1), 2006 (n=1), 2004 (n=1), 2003 (n=2), and 2002 (n=1).The continent where most of them were developed was Asia (5 studies, from Iran, Israel, China, Taiwan and Japan), followed by North America with 4 studies (2 from the USA and 2 from Canada), while 2 studies were developed in Germany and 1 in Australia.In addition, all cardiac catheterizations were elective procedures.The non-randomized clinical trials used music (12) and educational videotapes (13) as strategies to reduce patients' anxiety.Lee et al. (12) randomized patients based on the day of the procedure (patients submitted to the procedure on Wednesdays were assigned to the control group and patients submitted to the procedure on Thursdays were assigned to the intervention group).Chair et al. (13) randomized patients into two groups based on the presence of patients at the pre-admission educational assessment session (patients who were present at the pre-admission assessment session were allocated to the experimental group, whereas the remaining patients were allocated to the control group).
Box 1 shows that the instruments most frequently used to assess patients' anxiety were Spielberger's State-Trait Anxiety Inventory (n=9), the Visual Analogy Scale (n=3), the Numerical Value Scale (n=2) and the Depression, Anxiety and Stress Scale (DASS-21) (n=1); three of the studies reviewed used two distinct scales to assess patients' anxiety (14)(15)(16) .To identify the effect of music on anxiety levels in Chinese patients before cardiac catheterization (12) .To examine whether exposure to music therapy and psychoeducational training reduce objective and subjective anxiety, leading to a reduction in anxiolytic medication (15) .To investigate the effects of music on patients' anxiety, angina, pain, relaxation and comfort during angiographic procedures and to evaluate the differences between genders (16) .To examine the effect of music on the levels of anxiety, stress and depression experienced by patients undergoing coronary angiography (17) .To evaluate the effect of music on psychophysiological aspects of patients awaiting cardiac catheterization (18) .although a reduction was obtained in their scores, no significant difference was observed between the groups.When each group was evaluated individually, however, significant differences were observed between the first and the second evaluation in both groups (p<0.001).
Regarding the variability of heart rate, there was no significant difference in any of the evaluations between the groups.Regarding musical preference, piano music was most commonly chosen.There was no correlation between musical preferences and alterations in the scores of physiological variables.However, there was a significant difference in musical preference and anxiety (p=0.05),indicating that the greater the patients' satisfaction in choosing the music type, the lower their anxiety.To assess the anxiolytic effects of different music styles in patients submitted to cardiac catheterization (19) .Jadad Scale: 2 Intervention group: patients who chose one of the following options during the procedure: classical music (35), modern relaxing music (42), jazz (23), no music (0).Control group: patients who were allocated, without choosing the type of music, in one of the following options, during the procedure: classical music (25), modern relaxing music (25), jazz (25), no music (25).
Observation: all music had 60 to 80 beats per minute, a regular rhythm, and the volume was adjusted according to the permitted limit.In the intervention group, modern relaxing music was the most effective for anxiety reduction compared to other music styles, and in the control group, classical music and jazz were the most effective.
Patients who listened to a specific type of music had a statistically significant anxiety reduction when compared to the group that did not undergo this intervention (14.9 versus 6.2; p<0.0001), and patients who did not choose the type of music had a significant reduction in anxiety levels when compared with the other group (16.8 versus 13.3; p=0.0176).
To determine whether music therapy and sensory information are effective in reducing anxiety, uncertainty, heart rate and breathing, and whether it improves mood before cardiac catheterization (20) .To determine the effect of music on controlled psychophysiological stress response to cardiac catheterization (21) .Jadad Scale: 3 Intervention group: in addition to the same standard care received by the control group, patients listened to music before, during and after the procedure, using earphones.The music therapy started after patients had completed the questionnaires prior to the procedure, and they continued to listen to music (provided they wanted to) during and after the catheterization, before the second evaluation.To measure the effectiveness of an educational video on reducing levels of uncertainty and anxiety for Chinese patients submitted to cardiac catheterization (13) .To examine the effect of a psychoeducational nursing intervention in patients' anxiety early in the waiting period for elective cardiac catheterization (14) .Anxiety increased in both groups over the waiting time (1.3 versus 1.6; p=0.028).
Anxiety was significantly higher in the control group (4.0 versus 5.2; p=0.002).Regarding quality of life and disease selfmanagement functional status, in the first evaluation there was no significant difference between the groups.However, a difference in quality of life (0.4 versus 3.2; p=0.06) was observed when the first and second assessments were compared.
To investigate, in two studies, if palm therapy is effective in reducing anxiety in patients submitted to cardiac catheterization (23) .To evaluate the efficacy of a 20-minute massage in the reduction in patient levels of pain, anxiety and stress before an invasive cardiovascular procedure; to assess patient satisfaction with the massage; to assess the feasibility of therapeutic massage practices before the procedure (22) .The following non-pharmacological strategies were utilized to reduce the anxiety of patients undergoing cardiac catheterization: music therapy (n=8; 66.7%) (12,(15)(16)(17)(18)(19)(20)(21) , educational videos (n=2; 16.7%) (13)(14) , massage (n=1; 8.3%) (22) , palm therapy (n=1; 8.3%) (23) and psychoeducational training (n=1; 8.3%) (15)   .One study (15) used two interventions (music therapy and psychoeducational training); however, music was its main intervention.Music therapy was shown to be effective in most of the studies, with p-values ranging from <0.001 to 0.033, as shown in Box 1 (12,15,(17)(18) .Several studies showed that music therapy reduced anxiety (12,15,(17)(18)(19) , stress, depression (17) and physiological markers of anxiety, such as systolic blood pressure, heart rate and respiratory frequency (13) , with statistically significant differences in comparison with control groups, as shown in Box 1. Regarding the moment when the intervention was carried out, some studies performed the interventions before catheterization (12,18,20) , others during the procedure (15,(18)(19) , another before and after the hemodynamic procedure (17) and another before, during and after the cardiac catheterization (21) .However, no study identified whether before or during the procedure was the most effective for the intervention.
Patients did not choose their preferred music in most of the studies (15)(16)(17)(20)(21) . One stuy demonstrated that patients who did not get to choose the type of music had a significant reduction in anxiety compared to patients able to choose their preferred music (p=0.0176)(19) .Generally, the music was relaxing (60 to 80 beats per minute) with no drastic volume or rhythm changes.
In addition to music therapy, other strategies were identified to reduce anxiety in patients undergoing to cardiac catheterization, although there were very few of these.Other interventions discussed in this review include: educational videos, massage, and palm therapy.
Two studies showed that educational videos were effective in reducing anxiety in patients who underwent cardiac catheterization (13)(14) .This strategy was effective because the videos contained information about the procedure and discussed and anticipated feelings that may arise during the procedure.
It was observed that the strategy of administering a massage for 20 minutes was also effective for anxiety reduction in these patients (22) .A study by Blaer et al. (23) showed that anxiety levels were reduced in the group that received palm therapy for 45 minutes.Palm therapy is a moderate continuous pressure on specific points of the palm that are supposed to represent specific areas of the brain and may be effective for reducing some signs and symptoms presented by patients (23) .

DISCUSSION
There is very little evidence in the literature about the effectiveness of non-pharmacological strategies for anxiety reduction in patients undergoing cardiac catheterization.In the majority of the studies identified in this review, non-pharmacological interventions were effective, music therapy being the most commonly used.
Music can help eliminate pain and reduce stress and tension, besides inducing relaxation (24) .Music is an ideal non-pharmacological intervention in that it is easily accessible, inexpensive and favors anxiety reduction and physiological activity (25) .
Among the studies that used music therapy as an intervention to reduce anxiety and let subjects choose their preferred music, it was observed that the most common music style chosen was classical music.However, from our review, it appeared that choosing the music did not influence patients' level of anxiety.One explanation may be that patients frequently expressed doubt in their decision and worried that health professionals may not like their choice (19) , subsequently increasing anxiety levels.
In spite of music being the intervention most frequently used as a strategy for anxiety reduction in patients undergoing cardiac catheterization, there was no consensus about the best type of music, or the best time for listening to it.This consensus may not be established due to the heterogeneity of methods used in the reviewed studies.In this context, future studies should be conducted with consistent methodology.
Although the other strategies identified in this review (educational video, massage and palm therapy) have shown positive results in reducing anxiety in patients undergoing cardiac catheterization, there are few publications to highlight their clinical benefits.For this reason, further studies are needed to validate these findings.
The use of educational sessions before admission, such as instructions about the procedure through videos, showed effective improvements in the knowledge of hospital procedures and a reduction in patients' anxiety (26) .Studies show that patients become calmer when they have the opportunity to know more about the upcoming procedure; nurses can mitigate patient anxiety by offering systematized information about the procedure to the patient (13)(14) .However, a few studies were performed with the aim of identifying the effectiveness of educational videos to reduce the level of anxiety of patients undergoing cardiac catheterization.
In relation to the study on massage, it was observed that it promotes relaxation, and reduces stress and anxiety (27) .The study that used palm therapy was based on the theory that the palm of the hand represents the entire body in miniature and that certain points correspond to specific areas of the brain, both motor and sensory.Hence, moderate continuous pressure on specific points of the palm of the hand can reduce anxiety effectively (23) .Studies show that alternative therapies are increasingly being used to reduce patients' anxiety (28)(29) , and these interventions must be considered by health professionals when dealing with anxious patients.
It is worth emphasizing the methodological quality of the reviewed studies.The majority of studies were considered of good quality.The studies classified as poor did not describe how the authors performed the randomization (18)(19) , did not explain the account of all patients (12,18) or did not randomize the patients (12)(13) .The majority of the articles reviewed did not describe the study settings and did not control some aspects that could have changed patients' anxiety, such as the light color (30) .Another result that should be emphasized is that, although most of the studies were clinical trials, sample sizes were small, ranging from 17 to 238 participants; some studies did not calculate sample size.Others studies are needed to validate these results.Another limitation is that we did not include all relevant studies due to the exclusion criteria "full text not available".

CONCLUSION
This review identified strategies used to reduce anxiety in patients submitted to cardiac catheterization, including music therapy, palm therapy, educational videos and massage.These studies suggested that anxiety can be reduced through these four strategies and may be administered by nursing staff.It is known that reducing anxiety can decrease heart rate and blood pressure, thereby reducing oxygen consumption, which may be beneficial for the patient's prognosis.However, because this is an integrative literature review, we did not perform a meta-analysis and future systematic literature reviews should be performed in order to identify the effectiveness of these strategies.
Article retrieval and selection, São Paulo, Brazil, 2015 identification of article, journal, authors, country, language, year of publication, institution where the study is based, type of publication, objective or research question, sample, data analysis, interventions, results, analysis, implications, level of evidence and limitations of the study.