Telerehabilitation for Cardiac Patients: Systematic Review

Dentre as intervenções não farmacológicas utilizadas no tratamento das doenças cardiovasculares encontrase a reabilitação cardiovascular. Apesar dos benefícios comprovados da reabilitação cardiovascular, verifica-se um baixo índice de adesão dos pacientes cardiopatas; para tanto, uma alternativa vem sendo realizada, a telerreabilitação tem ganhado espaço e muitos estudos estão sendo realizados para verificar sua eficácia. Revisar a literatura e verificar a eficácia da telerreabilitação na população cardíaca. Trata-se de uma revisão sistemática da literatura, com busca realizada nas fontes de dados eletrônicas MEDLINE/PubMed (Medical Literature Analysis and Retrieval System Online), PubMed Central® (PMC), Cochrane Library, Physiotherapy Evidence Database (PEDro), utilizando a combinação de descritores, incluindo termos do Medical Subject Headings (MeSH) e seus entry terms. Os termos MeSH utilizados em conjunto foram: “telerehabilitation” AND “cardiac rehabilitation”. Posteriormente, foi realizada busca manual por meio de artigos selecionados, e busca na literatura cinza. A estratégia de busca reuniu 154 estudos, dos quais 109 foram excluídos por estarem duplicados nas bases de dados e 29 por não serem estudos clínicos. Foram incluídos 16 estudos clínicos para análise na íntegra, dos quais 2 foram excluídos por serem prospectivos, 2 por duplicidade de amostras e 5 por não contemplarem desfecho. Ao final, foram incluídos 7 estudos. A reabilitação cardíaca utilizando telerreabilitação é uma alternativa viável e segura, apresenta alta adesão dos pacientes cardiopatas e pode ser utilizada em adição aos programas de reabilitação cardiovascular convencionais ou ainda de maneira isolada.


Introduction
Cardiovascular diseases (CVD) are increasingly frequent.Their epidemiology has been compared to that of the great epidemics of the past centuries. 1According to the World Health Organization (WHO), in recent decades, approximately 30% of a total of 50 million deaths were caused by CVD, 17 million people worldwide. 2,3milarly, Brazil has equally alarming indices, with CVD as the major cause of death, representing 30% of all causes of death recorded, and being the third major cause of hospitalization in the country. 2,3In addition, WHO states that those diseases are a threat to the socioeconomic development, mainly due to the large number of premature deaths that could be prevented by reducing the risk factors. 4me nonpharmacological interventions are used to treat CVD, such as cardiovascular rehabilitation (CVR), consisting in the set of interventions aimed at improving the patients' physical, psychological and social conditions. 5Over the past 40 years, the role of the CVR services in the secondary prevention of cardiovascular events has been recognized and accepted by health organizations, and the interventions used in the care provided to patients with CVD have proved fundamental to treat those individuals. 6spite the confirmed CVR benefits, low adherence of the patients with CVD has been observed.Some studies have attributed it to the lack of transportation for the patients, lack of time, return to work or financial problems, those being the major hindrances to participation in CVR programs.Some authors have reported that only 27% of the patients adhere to CVR. 7 Therefore, different strategies to encourage physical exercise and changes in behavior and lifestyle are necessary and should be implemented to modify the patients' risk factors, preventing new cardiovascular events and enabling the patients' return to their usual daily activities. 7nsidering all that and the recent technological advance, an alternative to conventional CVR has been the use of the technology of telemedicine, 8 which proposes the delivery of healthcare services by use of information and communication technologies in situations where a health professional and a patient (or two health professionals), each in a different place, can communicate in real time, or even enables data storage for further analysis, consultation and opinion.In addition, it provides the safe transmission of medical data via texts, sounds and images required for prevention, diagnosis, treatment and patients' follow-up. 9habilitation using telemedicine resources is known as telerehabilitation and has gained importance.Several ongoing studies are assessing its efficacy, but they are heterogeneous and use different tools to conduct telerehabilitation.Thus, this study was aimed at reviewing the literature and assessing the efficacy of telerehabilitation for cardiac patients.

Methodology Study design and search strategy
This is a systematic review of the literature, which does not require Ethics Committee in Research approval, but is being analyzed by the International P r o s p e c t i v e R e g i s t e r o f S y s t e m a t i c R e v i e w s (PROSPERO).In addition, this systematic review has met the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).The search was conducted in the electronic databases MEDLINE/PubMed (Medical Literature Analysis and Retrieval System Online), PubMed Central ® (PMC), Cochrane Library, and Physiotherapy Evidence Database (PEDro), using the combination of descriptors, including terms of the Medical Subject Headings (MeSH) and its entry terms.The MeSH terms used in combination were: "telerehabilitation" AND "cardiac rehabilitation" (Table 1).Then, a manual search by use of the articles selected, as well as a search in the gray literature, was conducted.

Inclusion and exclusion criteria
This study included all randomized or nonrandomized clinical trials found in the databases, published in Portuguese, English or Spanish, with the full text available and no date restriction, conducted in human beings aged at least 18 years, in which patients with CVD participated in CVR programs, using telerehabilitation or telemedicine resources.
Studies with the following characteristics were excluded: duplicate studies; not performed in human beings; not published in full text; whose population had been studied in more than one study and whose outcomes were similar, situations in which the first study was considered for inclusion in this review.
Two reviewers evaluated independently the abstracts.The studies selected had their full text assessed for inclusion according to the criteria established.

Identification and selection of studies
Two reviewers independently read the titles and abstracts of each pre-selected study, identifying    separately the articles that met the inclusion and exclusion criteria.In the next phase, each reviewer read the full articles that met the criteria presented in the abstract, and selected only those compatible with the criteria proposed for this systematic review.In case of doubt, a third reviewer would be consulted; however, in this study, there was no disagreement between the first two reviewers.

Data extraction
Two researchers were responsible for data extraction.The following characteristics were extracted from the studies: title, authors, publication year, name of the scientific journal of publication, publication form, keywords, geographical origin, study design, sample size, methods, study period, instrument used for telerehabilitation, other results and conclusions.In addition, the following data about the participants of each study were recorded: number, sex, age, interventions performed, rehabilitation time, outcomes.The risk of bias of the randomized clinical trials was assessed by using the Cochrane Collaboration's tool (Table 2).

Data analysis
Data analysis was performed in a descriptive and qualitative form, being presented as figure and tables.

Results
This systematic review gathered 154 studies identified through the determined search strategy in electronic databases.Of those 154 studies, 109 were excluded due to duplication in databases, 29 were excluded because of being abstracts, systematic reviews or other studies.Thus, 16 clinical trials were included for complete analysis, of which 2 were excluded because of their prospective character, 2 were excluded due to cohort duplication, and 5 were excluded for not contemplating an outcome.Thus, 7 studies were included for complete analysis in this review (Figure 1).Data regarding the methodology and results of the studies included in this review are shown in Table 3.They assessed the effectiveness of telerehabilitation as compared to conventional CVR, in addition to comparing the effectiveness of conventional CVR to that of hybrid cardiac rehabilitation (HCR), in which the patient practices the exercises at home using sensors that transmit information to the rehabilitation center.Some studies' outcomes were as follows: influence of rehabilitation on oxygen consumption (VO 2 ), physical capacity, acceptance and efficacy of the technique in different patients.Of the underlying pathologies that led the patients to look for rehabilitation, the following stand out: coronary artery disease (CAD), chronic heart failure (CHF) and diabetes mellitus (DM).

Discussion
The present systematic review of the literature analyzed seven clinical trials involving telerehabilitation for patients with CVD, adding up to a sample of 1,133 patients.The studies were heterogeneous regarding both their populations and interventions; thus, a meta-analysis could not be performed.Catalina et al. 10 have suggested that CAD is still one of the major causes of premature death in Europe and worldwide, being considered a public health problem.Considering that, some studies have assessed the effects of CVR and telerehabilitation on patients with CAD.According to Vieira et al., 11 the group undergoing telerehabilitation performed better in executive functions, conflict resolution and attention as compared to the group undergoing conventional CVR.According to Brouwers et al., 12 telerehabilitation has provided better physical activity levels in the long run as compared to conventional CVR.Likewise, other authors have evidenced that patients with CAD

References
submitted to telerehabilitation showed a significant increase in their daily activity level and VO 2 peak after 6 weeks.
Hybrid cardiac rehabilitation has been used for patients with CAD.Szalewska et al. 13 have compared the use of that technique in patients with CAD and DM and patients with DAC but without DM.Those authors have reported that adherence to HCR was high, and that HCR was effective in patients with and without DM.
According to Bocchi et al., 14 heart failure (HF) is the common end of most heart diseases, being classified as an epidemic and representing one of the most important current clinical challenges in health care.Telemedicine has been increasingly used for that population.In a clinical study with 111 patients with HF, Piotrowicz et al. 15 have shown that home-based rehabilitation using telerehabilitation caused reversion of depression and improved physical capacity in those patients.
Corroborating the results demonstrated, Bernocchi et al. 16 have suggested, in a study with 112 patients diagnosed with HF and chronic obstructive pulmonary disease (COPD), that a home-based telerehabilitation program increased the walked distance, reduced the dyspnea and improved the functionality of those individuals as compared to those of the group undergoing conventional CVR, confirming the feasibility and effectiveness of telerehabilitation programs for patients with HF and COPD.
Hybrid cardiac rehabilitation has also been used for post-acute myocardial infarction (AMI) patients.In a study with 87 post-AMI patients, the authors have evidenced that HCR facilitated patients' adherence to the training program, but the return-to-work indices were higher in men than in women, although the physical capacity improvement was similar for both sexes. 17milarly to the studies assessed, Piotrowicz et al. 18 have confirmed in a sample of 365 patients that HCR using telerehabilitation resulted in a significant improvement in functional capacity, being a feasible, safe and well accepted rehabilitation form, with a high index of patients' adherence.

Conclusion
After analyzing the studies, we concluded that HCR and home-based rehabilitation using telerehabilitation are feasible and safe alternatives, with high adherence by patients with CVD.They can be added to conventional CVR programs or be used in isolation.In addition, they help to improve depression, functional capacity and the physical activity level.

Figure 1 -
Figure 1 -Flowchart of the selection of the studies.
were performed at the center, and the others at home with tele-ECG monitoring.Before and after the trainings, all patients underwent a symptom-limited exercise stress test.The evaluation included the results of exercise tests.HCR resulted in a comparable improvement in physical capacity in post-AMI low-risk male and female patients.were monitored via telephone with a device to record ECG and to transmit data via cellular phone to the monitoring center.Automatic ECG recording was pre-defined and coordinated.The influence on physical capacity was assessed by comparing the changes in: time of the exercise test, functional