This was a single-blind randomized controlled clinical trial that was conducted with a pretest–posttest design from April to October 2015. The study population consisted of patients who were scheduled for coronary artery angiography in selected hospitals affiliated to Shiraz University of Medical Sciences, Shiraz, Iran, namely Namazi Hospital, Faghihi Hospital, Kowsar Heart Hospital, and Al-Zahra Heart Hospital. Two cardiologists who performed coronary artery angiography in the selected hospitals were involved in the study. The investigation conformed with the principles outlined in the Declaration of Helsinki. The study protocol was explained to all participants and written informed consent was obtained. Furthermore, the participants were free to withdraw from the study at any stage. The Ethics Committee of Shiraz University of Medical Sciences approved the protocol of this study (Code: CT-93–7343). In addition, the protocol of this project was registered in the Iranian Registry of Clinical Trials (IRCT) website with code IRCT2015030121283N1 (https://​www.​irct.​ir/​trial/​18683).

The minimum sample size of 40 per group was estimated using the means comparison formula based on mean anxiety scores, on the basis of an alpha = 0.05 significance level, a power of 80%, and anxiety scores of 9.6 ± 2.22 in the intervention group and 11.8 ± 4.28 in the control group reported by Hanifi et al. [12]. By considering the loss to follow-up of patients, especially because of withdrawal from the study or coronary angiography intervention cancellation, two to three extra patients were enrolled in each group to the study.

The inclusion criteria were as follows: (1) the scheduled coronary artery angiography would be the first experience of the patient with the procedure; (2) an age range of 25–75 years (the common age range in adults for coronary angiography); (3) lack of a job related to medical care and treatment; (4) ability to receive text messages via cell phone and to use a computer for watching multimedia content stored on a DVD; (5) literacy (defined as being able to read and write with completion of a minimum of five years of elementary school); and (6) a minimum of four days being left until the angiography appointment. The exclusion criteria were as follows: (1) experience of another invasive diagnostic procedure, such as transesophageal echocardiography or prior angiography; (2) a low level of consciousness or known case of a psychological disorder; and (3) a positive history of psychiatric medication use.

The Random Allocation Software Ink (Version 1.0, May 2004) was applied to create a randomization table, considering a block size of six including the equal times of each intervention of the study in each block. Therefore, the patients were randomly assigned and allocated to three groups, namely the DVD (n = 40), text messaging (n = 40), and control (n = 40) groups, coding using the letters A, B, and C, respectively, thereby blinding the staff who evaluated the patients as well as the statistical analyzer.

The data collection instruments included a researcher-made demographics questionnaire and Depression Anxiety Stress Scale-21 (DASS-21). This scale is used for measuring depression, anxiety, and stress using a total of 21 items. The instrument is designed based on the four-point Likert scale scored with 0 for never, 1 for sometimes, 2 for often, and 3 for almost always. In this regard, stress was evaluated through items 1, 6, 8, 11, 12, 14, and 18, anxiety through items 2, 4, 7, 9, 15, 19, and 20, and depression through items 3, 5, 10, 13, 16, 17, and 21. For obtaining the total score in each domain, the scores of the mentioned items are summed up. Antony et al. (1998) used Cronbach's alpha coefficient for the internal consistency of the scale, reporting values of 87, 82, and 78 percent for the stress, anxiety, and depression domains, respectively. The overall reliability of the scale was found to be 93% [18]. The reliability of the Persian version of this questionnaire was ascertained in one study among 390 individuals from the general population of Tehran, Iran, with Cronbach's alpha coefficient value being reported at 0.85 for the depression domain, 0.85 for the anxiety domain, and 0.87 for the stress domain. Furthermore, the test–retest reliability reportedly revealed interclass correlation with absolute agreement between first and second evaluations with scales of 0.77, 0.89, and 0.85 for the depression, anxiety, and stress domains. The study also revealed acceptable discriminate validity in all domains of the questionnaire [19].

Overall, 120 patients who were scheduled for elective coronary artery angiography and met the inclusion criteria were enrolled in the study. According to the block randomization method, the patients were randomly divided into three groups: the text messaging group, the DVD group, and the control group. In the pretest stage, the patients were asked to complete the demographic questionnaire (age, gender, education, and marital status) and the DASS-21. During the four days leading to the appointed day of angiography, the patients in intervention group 1 were sent seven short text messages (via mobile phone) each day with information regarding the purpose and procedure of coronary angiography and what the patients should know and do in the peri-coronary artery angiography period. The patients in intervention group 2 received a DVD containing 15 min of educational multimedia content. The educational content of the text messages, the DVD, and the pamphlets were practically the same, except that the DVD also contained related pictures and animations. The control group simply received the conventional pre-operation hospital care, which consisted of basic verbal information and a pamphlet on what to do before angiography (e.g., refraining from food), how angiography is performed, and how the medication should be taken. The content validity of the text messages, DVD multimedia, and pamphlets was approved by a six-member team including two cardiologists, two nurses each with a Ph.D. degree, and one general physician with a master’s degree in medical education. The contents of the multimedia DVD were produced using Adobe Flash Professional CS6 2015.

Thirty minutes after the completion of coronary artery angiography, the questionnaire was filled out again by the patients to determine the posttest scores. Beforehand, the researcher asked the patients whether they received and read the messages or watched the DVD content; individuals who did not take up the patient education were excluded at this point in the study.

The data were analyzed using SPSS, version 18. The Kolmogroph-Smirnoff test was used to evaluate the data distribution. The chi-squared test and Fisher's exact test were used to compare the three groups in terms of their demographic variables; analysis of variance (ANOVA) was used with a post hoc test (Tukey HSD) to compare the patients’ anxiety, stress, and depression scores. The paired t-test was used to compare the scores of the DASS-21 questionnaire before and after the intervention separately in each group. A P-value of less than 0.05 was considered significant.

The results of the present study showed that patient education via multimedia and text messaging was effective in reducing negative psychological parameters in patients after angiography. These interventions are recommended for patient education purposes and it is suggested that nursing students should be introduced to such methods of providing patient education and their advantages. These methods can also be used for on-the-job training for nurses’ problems.