This was a longitudinal, observational study. The study was approved by the Xinhua Hospital Research Ethics Board. PCI patients at the Xinhua Hospital affiliated with Shanghai Jiaotong University School of Medicine and Shanghai Sixth People’s Hospital were recruited between December, 2016 and November 2018. Neither center has a CR program.

The research nurse at each hospital approached patients during hospitalization to invite them to participate (informed consent). Data were collected at 4 points: (1) during hospitalization (after PCI but before discharge), (2) 1 month (± 3 days) post-discharge, (3) 3 months (± 1 week) post-discharge, and (4) 6 months (± 1 week) post-discharge. Data were collected from the electronic medical records and through on-site interviews in Mandarin, including during clinical follow-up visits post-discharge. Specifically, after discharge, patients were seen regularly at a clinic for follow-up by the physician who did the PCI procedure. When the patients were coming for the appointment closest to the time of their next scheduled research follow-up, the research nurse would call the patients to invite them to come earlier to allow for data collection. Patients were then provided questionnaires to assess outcomes of interest, including psychosocial well-being and ACEs. For patients who missed post-discharge clinic appointments, telephone interviews were used to obtain follow-up data.

Inclusion criteria were: age 18–75 years, hospitalized for PCI, planning to receive follow-up care from same institution, and sufficient ability to understand the assessment questions and communicate responses. Exclusion criteria were: patient history of serious mental illness (self-reported to resident), severe arrhythmia, heart failure, cardiogenic shock or other life-threatening conditions, and failed PCI.

At recruitment, clinical characteristics of patients were extracted from electronic medical records including cardiac history, cardiac risk factors, disease severity indicators, characteristics of the PCI (including length of stay), cardiac medications and blood work results. The Barthel index, [19] which characterizes activities of daily living, was extracted from the electronic patient record.

ACEs included the following: death (any cause), re-hospitalization (cardiac-related), myocardial infarction (non-fatal), stroke, heart failure (HF) development or exacerbation, PCI-related complications (in-stent restenosis, stent thrombosis or major bleeding event), peripheral vascular embolism, recurrent angina, among others (i.e., arrhythmias, coronary revascularization and transient ischemic attacks). ACEs were ascertained through the self-report questionnaire (for events occurring outside the centre) and from electronic patient medical records at each assessment point.

Risk factors assessed at each time point included blood pressure, which was assessed by a trained nurse using a sphygmomanometer. Lipids (total cholesterol [TC], triglycerides [TG], low-density lipoprotein [LDL] and high-density lipoprotein [HDL] were assessed at the point of admission into hospital and after 6 months using a blood test. Additionally, patient self-reported tobacco use, alcohol use, physical activity (duration, intensity, and type) and medication adherence (patients were asked if they take their medication regularly or not; measured on 5-pt Likert-type scale) were assessed at most assessment points. The psychometrically-validated Coronary Artery Disease Self-Management scale (CADSMS) [14] was also administered at all but the 2^nd assessment (Fig. 1). It consists of 27 items in 7 areas: leisure management, symptom management, emotional/ cognitive management, first aid education, disease knowledge, daily life management, and treatment compliance. Response options are on a 5-point Likert scale; The item scores for each subscale are summed. A total score is also computed, ranging from 27 to 135 points, with higher scores indicating better individual self-management behavior. The CADSMS scale has good retest reliability (intra-class correlation = 0.910), internal consistency (Cronbach’s α = 0.913), and validity [15].

Psychometrically-validated, translated scales were also administered at each assessment point to assess psychosocial well-being (Fig. 1). The Seattle Angina Questionnaire [16] (SAQ; physical limitation, angina stability, angina frequency, treatment satisfaction, disease perception subscales), Hospital Anxiety and Depression Scale [17] (HADS), and the Pittsburgh Sleep Quality Index [18] (PSQI; 7 subscales) were assessed at each point. The SF-12 (QoL) [19] was administered at 3 of the 4 assessment points only: in-hospital as well as at 3 and 6 months post-discharge. All 4 scales are shown to be reliable and valid [16‐19].

Statistical Package for Social Sciences (SPSS v.26) was used for analyses. A p-value < 0.05 was used to denote statistical significance. First, differences in the sociodemographic and clinical characteristics of patients retained at 6 months post-discharge were compared to those lost to follow-up using t-tests or chi-square (Fisher’s exact test where cell sizes small) as applicable.

ACEs, risk factors and psychosocial indicators were described at each assessment point, and change over time in the latter 2 assessed using repeated measures analysis of variance (ANOVA), with adjustment for PCI indication and Barthel index. Finally, clinical and psychosocial correlates of ACEs were investigated. First, differences in the sociodemographic, clinical and psychosocial characteristics at the initial assessment point of patients with and without ACEs were compared using independent samples t-tests and chi-squared analysis, as applicable. Variables that were found to be significantly associated with ACEs in these bivariate analyses were then included in a multivariate logistic regression, to test their association with ACEs, excluding those with indication of multicollinearity.

As shown in Fig. 1, there were 610 consenting patients; their characteristics are shown in Table 1. Two hundred and sixty-eight patients (43.9%) had a body mass index > 25 at the time of the PCI. Barthel index scores indicated that study participants were able to complete daily activities independently, exhibiting only minimal dysfunction. Almost half the sample received PCI without confirmed acute coronary syndrome (ACS).

Of these, 491 (80.5%) patients were retained at the final 6-month assessment (Fig. 1). Differences in patients’ characteristics at the time of PCI by follow-up status are also presented in Table 1. Patients who completed follow-up had significantly different medical insurance sources, were less likely to have had previous cardiac events and PCI, less likely to have comorbid kidney and lung disease, were more likely to have had confirmed ACS as their indication for the PCI, had different culprit vessels, higher D-dimer, had lower Killip classification, ejection fraction and brain natriuretic peptide, were less able to engage in activities of daily living (Barthel Index), as well as used more lipid-lowering and anti-hypertensive medications (but less proton pump inhibitors) than those lost to follow-up. No other differences were observed.

ACEs are shown in Fig. 1; There was only 1 death. Among those retained at 6 months, over the 6 months, 82 (16.7%) participants had any ACE at any time point, which was most commonly recurrent angina.

Risk factors and their management are shown in Table 2. Systolic BP went down significantly over time. As shown, at 6 months post-PCI, most patients were at guideline target. Patients’ salt intake, and fried food consumption decreased significantly over the 6-month period. Additionally, physical activity and medication adherence increased significantly. Lastly, there were significant increases across all subscales of the CADSMS except emotional/cognitive management, indicating improved risk factor self-management.

QoL indicators are shown in Table 3 and Fig. 2. The physical composite health score of the SF-12 was low at time of PCI, and increased significantly over time. Similarly, significant differences were observed with regard to symptoms over the 6 months, with all SAQ subscales increasing from the time of the PCI (it appeared the greatest increases occurred in the first month) but the treatment satisfaction subscale. Increases on the anginal stability and frequency subscales could be considered clinically meaningful (Fig. 2). Angina symptoms were good to excellent throughout the 6-month trajectory.

Other psychosocial well-being indicators are shown in Figs. 3 and 4, as well as Table 3. Distress was high (particularly anxiety), and still depressive symptoms were found to significantly increase from the time of PCI (anxiety remained consistently high). On the contrary, 4 of the PSQI subscales – sleep quality (p = 0.003), sleep latency (p = 0.041), sleep disturbance (p < 0.001), and daytime dysfunction (p < 0.001) were found to decrease significantly over 6 months, indicating improved sleep quality (change in total score did not sustain adjustment; Table 3).

Patients who had any ACE over the 6 months were significantly more likely to be older, have had a confirmed ACS (and accordingly had a higher degree of stenosis, particularly in the left main artery), higher d-dimer, and to be on ACE-inhibitor and anti-hypertensive medications than those who did not at time of PCI. They also had lower Barthel index scores, ejection fraction, b-type natriuretic peptide levels, and were less likely to be on proton pump treatment than those who did not (Table 1).

With regard to associations with psychosocial indicators at 6 months, those with an ACE at any point had significantly greater depressive symptoms (p < 0.001), and significantly less anxiety (p < 0.001). Those who had any ACE at any time point also had poorer physical (p < 0.001) and mental (p < 0.001) QoL. With regard to the SAQ, those who had an ACE also had significantly greater physical limitations (p = 0.010), angina frequency (p = 0.007), and poorer disease perceptions (p < 0.001). They had poorer sleep quality (daytime dysfunction [p = 0.020], sleep disturbance [p < 0.001] and sleep latency [p < 0.001]). Finally, those with an ACE had poorer emotional/cognitive self-management of their CAD (p < 0.001) and first aid knowledge (p = 0.008), but better symptom management (p < 0.001) than those who had no ACE at any point. No other differences were observed.

In logistic regression analyses assessing correlates of ACEs with ten significant independent variables from the above bivariate analyses (i.e., age, PCI indication, physical QoL, anxiety symptoms, depression symptoms, sleep disturbance, sleep latency, emotional/cognitive management, disease perception and anginal frequency), higher age (odds ratio [OR] = 1.029 [95% confidence interval [CI]: 1.00 – 1.06], p = 0.045), higher sleep latency (OR = 1.48 [95% CI: 1.03 – 2.10], p = 0.032), and depressive symptoms (OR = 1.20 [95% CI: 1.02 – 1.41], p = 0.024), as well as lower anxiety (OR = 0.79 [95% CI: 0.67 – 0.93], p = 0.005) survived this adjustment.

Caution is warranted in interpreting these findings. First, this was a convenience sample; as such, it is unknown whether there could be selection bias in the sample, particularly considering response rate was not tracked. For information, Xinhua Hospital performs approximately 1500 PCIs per year. Indeed, second, generalizability is also limited for a few reasons. They are limited to patients in Shanghai; whether findings are applicable to other cities or regions of China is unknown. Moreover, participants were primarily male. Third, there was some retention bias in the sample, further limiting the generalizability of findings from the latter assessments. Fourth, sample size was not calculated a priori as we sought to observe clinical and psychosocial trajectory in the cohort; however considering the rule of thumb of 10 participants per variable, sample size should be considered sufficient for the second objective (i.e., we did not test 50 ACE correlates). Fifth, only 1 ACE was recorded at each time point, and was missing for some participants. Sixth, multiple comparisons were undertaken, inflating the possibility of error. Last, due to the nature of the study design, causal conclusions cannot be drawn.

In conclusion, through this study the nature and trajectory of PCI patients in a major Chinese city, where rates of these procedures are exploding, was explored. Just over 15% of patients had any ACE, and this was most often angina; However, overall anginal burden was not high, and improved meaningfully over time. Patient self-management and risk factor control were good, although tobacco use, salt and physical activity require more attention. Patients were highly anxious and depressed, and this did not improve with time. QoL was quite low. Results suggest centers may wish to re-visit patient selection criteria and processes for PCI, as well as implement mental health screening and treatment protocols, as can be achieved through CR.