Biopsychosocial Effects of Donor Traits on Heart Transplant Recipients

Introduction

Survival after heart transplantation has significantly improved with advancements in immunosuppressive and transplantation techniques [1]. In recent decades, medical care teams have increasingly focused on physiological and psychological functions after transplantation. Extensive investigations have evaluated physical and mental disorders, such as major depression disorder and anxiety [2–4], and occupational adjustment [5,6]. Changes in recipients’ emotions and temperament, memory, interests, professional skills, and gender identity reportedly reflect donor characteristics [7–9].

Pearsall et al interviewed 10 heart transplant recipients and found that each had 2 to 5 characteristics similar to those of their respective donors [7]. Similarly, Mauthner et al reported on 25 transplant recipients, of which 92% (23/25) mentioned changes in self-identity and perception, 36% (9/25) felt that the donor was still alive through the transplanted hearts, and 56% (14/25) mentioned that they had dreamed about or guessed the donor’s appearance [8]. Moreover, Anthony et al studied 27 teenage recipients, most of whom believed that the donor lived through their hearts [9]. Additional etiologies, other than organic causes, such as abnormal serum tacrolimus levels, have been proposed to explain the changes in affective disturbances and elusive delusions observed in heart transplant patients [10]. Liester proposed that donors’ emotions and temperament may be transferred through heart transplantation via cell signaling mechanisms, such as genetic or epigenetic pathways, the intracardiac nervous system, or the electromagnetic energy of the heart [11]. The cell signaling mechanism has been studied in animal models, showing that the sea mollusk Aplysia can acquire the same sensory responses as its trained companions through RNA transfer [12]. Regarding electromagnetic energy, the heart has the largest electromagnetic field in the body, which is 60 times greater than that of the brain [13]. As for the intracardiac nervous system, due to its similarity to the brain [14], it is possible that it plays a role in the storage and transfer of memory or personality. Before further research into potential mechanisms is conducted, the connection between donors’ and recipients’ characteristics through heart transplantation must be established. Such research is important in caring for patients undergoing heart transplantation in the modern era, when quality of life is as important as longevity.

Although heart transplant recipients can undergo psychological and lifestyle changes after transplantation, further investigation is needed to determine the clinical significance of these changes. In this study, we used qualitative and quantitative analysis methods to examine an issue rarely addressed in clinical practice: psychological and life transformation and adjustment in patients after heart transplantation. In addition to cardiac function, mental state is an important factor affecting recipients’ prognosis. Accordingly, we hypothesized that the heart may have the potential to influence emotions, temperament, or memory and that heart transplant recipients might exhibit the donor’s characteristics after transplantation. To test this hypothesis, we included donors’ perspectives from donors’ families to clarify the potential causes of post-transplantation psychological and lifestyle changes in recipients.

Material and Methods

STUDY DESIGN:

This study was approved by the Institutional Review Board of the National Cheng Kung University Medical Center (B-ER-109-234) and adhered to the International Society for Heart and Lung Transplantation statement on transplant ethics [15]. Data triangulations were used to verify the hypothesis [16]. Data from recipients, recipients’ family members, and donors’ family members were collected through comprehensive interviews. In the study, the qualitative method was primarily used, whereas the quantitative method with questionnaires complemented the qualitative result. We used a “convergent design” to collect qualitative and quantitative data simultaneously, which were then merged during the analysis phase. The qualitative data were analyzed using content analysis.

MATERIALS:

Using data from the National Cheng Kung University Hospital (NCKUH) database from 2005 to 2020, we prospectively recruited and interviewed the heart transplant recipients, their families, and donors’ families, and collected clinical background data on the recipients and donors.

First, the deceased recipients were excluded. Second, for better access, we preferentially recruited recipients and their corresponding donors’ families. The corresponding donors had undergone surgery at NCKUH or nearby hospitals (in Tainan or Kaohsiung City). We recruited recipients and their families first; if the recipients consented to an interview, the corresponding donors’ families were contacted to participate.

By phone call, we recruited recipients who were sufficiently healthy and able to understand and communicate, obtaining their verbal consent first. Afterward, we obtained formal written consent and conducted the interview in person. For the recipients’ family members, the same recruiting process was followed. For the corresponding donors’ families, we contacted the family members listed in the contact information and recruited those who verbally consented to an interview first. Subsequently, we obtained formal written consent and conducted the interview in person.

DATA COLLECTION OF QUALITATIVE DATA:

The concept of “phenomenology of perception”, proposed by Merleau-Ponty and describing how human experience or identity may change through modifying or transferring the body was used to guide the interview process in this study [17].

The interview was primarily conducted by CCH under the supervision of professional researchers YYH and JNR, who specialize in quantitative and qualitative analysis. Before the study, relationships were established between the interviewer and participants by the transplant case manager and the social workers. Participants were informed about the study’s objectives and procedures and the interviewer’s background via telephone before the interviews.

The interview was semi-structured, featuring open-ended questions, and included 5 domains: preference, emotions and temperament, memory, self-identity, and social identity. The domain of preference was categorized into 6 aspects: diet, color, clothes, people/objects/events, music, and sex. The domain of memory was classified into 3 aspects: special experiences related to dreams, special experiences other than dreams, and impressions on donors. The 5 domains were chosen based on the review article [11]. For recipients, all 5 domains were asked; for recipients’ family members, all domains except self-identity were covered in the interview; for donors’ family members, the first 3 domains – preference, emotions and temperament, and memory – were covered in the interview. The questions were adjusted individually for recipients, recipients’ family members, and donors’ family members.

Interview locations included clinical rooms, quiet public spaces in the hospital, patients’ homes, and quiet public spaces near the patients’ residences. The interviews were recorded after informed consent was obtained from the respondents, and field notes were also taken. In cases in which the respondents did not agree to be recorded, the interviews were transcribed verbatim by hand and converted into electronic records within 48 h after completion. Each interview lasted 20 to 30 min. No repeat interviews were conducted, and the transcripts were not returned to the interviewees.

DATA COLLECTION OF QUANTITATIVE DATA:

Quantitative data were collected to complement the domain of “emotions and temperament” using the Big Five Inventory-19 (BFI-19) questionnaire, which was verified for reliability [18]. The original version was BFI-44, created by John et al [19]. The Neuroticism-Extraversion-Openness Five-Factor Inventory scale, similar to the BFI-44, has been used in heart transplantation studies [20,21]. The BFI-19 questionnaire consists of 5 parts: extraversion, agreeableness, conscientiousness, openness, and neuroticism. It comprises 19 questions rated on a 5-point scale, ranging from 5 (strongly agree) to 1 (strongly disagree) for each question (Table 1).

Recipients and their families were requested to report the recipients’ status before and after transplants using the BFI-19 (recipients and their families completed 2 BFI-19 questionnaires, respectively). The donor’s families provided the information based on their knowledge of the donors. The survey took 10 to 15 min.

DATA ANALYSIS OF QUALITATIVE DATA:

In this study, we used a deductive research approach and used content analysis [22] to validate the hypothesis by examining interview data. The researcher first converted the audio files of the interview into verbatim digital records listing key questions, whereas handwritten verbatim transcripts were converted within 48 h after the interviews. The content analysis was conducted as follows: First, the answers to each question were summarized and assessed for recipients and their families to determine whether changes arose in each aspect. Second, for donors’ families, the answers to each core question were summarized. Third, the recipients’ and their families’ expressions of these changes (including tone, wording, and recipients’ interpretations of their changes) were analyzed and compared with how the corresponding donors were described by their families. Any changes similar to the traits of the corresponding donors were recorded and further discussed with the other members of the research team.

DATA ANALYSIS OF QUANTITATIVE DATA:

For the BFI-19 questionnaire, the Wilcoxon signed-rank test (Python 3.12.4 version) was used to test for significant differences within 2 categories, defined as follows: The first was “recipients’ perceptions of themselves before transplantation vs recipients’ perceptions of themselves after transplantation”. The second was “perceptions of recipients’ families about recipients before transplantation vs perceptions of recipients’ families about recipients after transplantation”. Additionally, the Spearman rank correlation (SPSS software version 25; IBM Corp, Armonk, NY, USA) was used to test for positive correlation in 2 categories, defined as follows: The first was “recipients’ perceptions of themselves after transplantation vs perceptions of donor’s families about the donors”. The second was “perceptions of recipients’ families about recipients after transplantation vs perceptions of donor’s families about the donors.” Statistical significance was set at P<0.05.

Results

SUMMARY OF CONFORMITIES OR SIMILARITIES BETWEEN RECIPIENTS’ CHANGES AND THE TRAITS OF CORRESPONDING DONORS:

For 3 main domains – preference, emotions and temperament, and memory – recipients’ change in each domain was compared with the traits of corresponding donors. For individual cases, 5 recipients (5/13, 38%) had 2 or more similar or conforming aspects with their corresponding donors (Table 3). Among all aspects, diet had the most conformities or similarities. The statistics of the other aspects are shown in Figure 2. The highlights of some aspects are shown as follows, and a summary of the important content is presented in Table 3.

PREFERENCES IN DIET:

Four groups of interviewees (cases 4, 9, 11, and 12) mentioned conforming or similar content in diet, specifically noting taste preference, such as a preference for spicy food, and food intake, such as a decreased amount of intake without hunger. The recipient in case 11 stated, “After the transplantation, my appetite seems to have decreased to about one-third. However, even though I eat less, I do not get hungry easily. I think such dietary habits may also be affected by the donor.” The recipient’s family said, “He does not make a special effort to refrain from eating. He simply started eating less naturally.” The donor’s family remarked, “My husband did not eat much, approximately 80% of a bowl of rice each meal, roughly the same as other men his age. He had a healthy appetite but ate at a slow pace.”

EMOTIONS AND TEMPERAMENT:

Three groups of interviewees (cases 5, 8, and 10) mentioned conforming or similar content related to emotions and temperament. Changes in positive emotions and temperament, such as being more patient or thoughtful, were reported. In case 10, the recipient stated, “I flew into a rage constantly before, but I have changed a lot after the transplantation. I think this change occurred naturally; I did not even notice it initially until others reminded me. I think perhaps it has something to do with the donor. Perhaps the donor was a kind-hearted, sweet-tempered person. Besides, I have become more thoughtful and perceptive of others’ personalities and characters. Personally, I think the donor must be the principal reason for these changes because I did not behave like this before!” The donor’s family remarked, “He was quiet, reticent, contemplative, and gracious. He did not talk much about himself. He was not argumentative and undertook what he did out of the kindness of his heart.”

For the complementary quantitative data from the BFI-19 questionnaires, 1 donor’s family (case 1) and 1 recipient’s family (case 13) were excluded due to missing data. Finally, 12 groups related to recipients or donors and 7 groups related to recipients’ families or donors were analyzed. The analysis showed no significant difference in the 5 parts between the status before and after the transplant and no significant positive correlation between the status after the transplant and the donors’ information (Table 4).

MEMORY: SPECIAL EXPERIENCES OTHER THAN DREAMS:

Three groups of interviewees (cases 5, 7, and 10) mentioned conforming or similar content related to special experiences other than dreams. Certain inexplicable experiences were noted. In case 5, the recipient stated, “Every time I come back for a check-up, I feel excited for no reason. Despite being nervous, I feel inexplicably cheerful. In addition, during the first 2 years after the transplantation, I would hear someone talking to me. It was a young girl’s voice calling my name in a soft tone.” The donor’s family said, “My daughter was a nurse. She liked being with older people. She was responsible, conscientious, and dedicated to her work. She often worked overtime till late at night.”

OTHER ASPECTS:

Regarding special experiences related to dreams, 2 groups of interviewees (cases 5 and 8) mentioned conforming or similar content. The dream content was associated with important life events in the donors’ lives, such as death or accident (case 8). Concerning memory-impression on donors, 2 groups of interviewees mentioned conforming or similar content. The impression was connected to the donor’s characteristics (case 10) or the donor’s family’s wishes (case 12). Regarding preference-color and preferences for people, events, and objects, 1 group of interviewees mentioned conforming or similar content in each aspect (cases 5 and 11, respectively).

CHANGES IN SELF-IDENTITY OR SOCIAL IDENTITY REPORTED BY RECIPIENTS AND THEIR FAMILIES:

Regarding domains of self-identity and social identity, neither the recipients nor their family members felt a change in their identity themselves. However, regarding the identity of the new heart, 3 recipients were not accustomed to their new hearts and expressed strong feelings that these were not their organs (cases 9, 11, and 12).

Discussion

LIMITATIONS:

This study had some limitations. First, the investigators were primarily responsible for determining whether the characteristics of both parties were similar or identical, which could be influenced by the investigator’s awareness and background knowledge. Second, due to the small sample size, extrapolation of our study findings should be approached with caution. Third, the donors in this study were represented by their family members, which may not reflect the actual condition of the donors. Fourth, recipients were interviewed after transplantation, which can introduce recall bias. Fifth, the duration from transplant to interview varied among recipients, and different post-transplant stages may have affected their perception of bodily changes and interpretation of characteristic changes. Sixth, the different attitudes toward heart transplantation and diverse sociocultural backgrounds may have influenced the data collection. Seventh, the study primarily relied on qualitative data, with quantitative data limited to the aspect of emotions and temperament. The limited quantity of quantitative data can affect the objectivity of the research. To achieve better results in the future, increasing the number of interviewers with different backgrounds, recruiting more family members or friends of donors, or using a prospective study to follow up with the recipients before and after heart transplants may be considered, to overcome limitations.

Conclusions

Our study revealed a few similarities in lifestyle between heart transplantation recipients after transplant and their corresponding donors, with 38% (5/13) of transplantation recipients having 2 or more similar or conforming aspects. We found changes in recipients’ preferences, emotions and temperament, and memories after transplantation, with a certain level of correlation with their corresponding donors. Identifying these characteristics might improve self-care ability and reduce life stress after transplantation. The mechanisms explaining these similarities require further investigation, and more rigorous, larger-scale clinical studies are required to further validate the correlations. In the future, we recommend first conducting a prospective study that traces patients from pre-transplant to post-transplant status to obtain more accurate interview information and avoid recall bias. Second, future research should incorporate more quantitative methods to complement qualitative research, thereby enhancing the credibility of the analysis. Third, in terms of basic research, the intracardiac nervous system and cellular memory warrant further studies to verify their potential in transferring individual characteristics. Our findings encourage clinicians to provide more comprehensive information during the preoperative informed consent and postoperative psychological evaluations, to provide recipients with more holistic care and an improved quality of life after heart transplantation.