Intervention：

(1) Implementation Location Department of Cardiology, The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine (2) Implementation Content Routine cardiac rehabilitation was implemented, with reference to the "Primary Care Guidelines for Cardiac Rehabilitation of Coronary Heart Disease (2020)" [81]. The guidelines state that "cardiac rehabilitation involves the application of five core prescriptions—medication, exercise, nutrition, psychosocial and behavioral interventions, and smoking cessation/alcohol restriction—along with comprehensive medical measures." Patients were provided with appropriate lifestyle guidance, including advice to maintain a low-salt and low-fat diet, quit smoking as soon as possible, control underlying conditions such as hypertension, diabetes, and hyperlipidemia, maintain emotional stability, adhere to a regular sleep schedule, and engage in appropriate daily physical activity. Based on patient symptoms, medications such as nitrates, beta-blockers, and calcium channel blockers were prescribed, accompanied by education on medication precautions and reminders for regular follow-up visits. (3) Implementation Methods 1) Pharmacotherapy: Optimal Drug Therapy (ODT) focused on pharmaceutical management, including the use of antiplatelet agents, lipid-lowering drugs, and beta-blockers to reduce cardiac workload, regulate blood lipid levels, and prevent adverse cardiovascular events. With reference to the "Guideline for Rational Medication in Coronary Heart Disease (2nd Edition)" issued in 2018 by the National Health Commission Expert Committee on Rational Drug Use and the China Pharmacist Association, patients took medications at physician-prescribed doses: A. Aspirin Enteric-coated Tablets (Shijiazhuang Pharmaceutical Group Ouyi Pharmaceutical, NMPA Approval No. H20153035, 100mg), orally. B. Isosorbide Mononitrate Tablets (Livzon Group Livzon Pharmaceutical Factory, NMPA Approval No. H10930189, 10mg), orally. C. Clopidogrel Bisulfate Tablets (Lepu Pharmaceutical Co., Ltd., NMPA Approval No. H20123116, 75mg), orally. D. Atorvastatin Calcium Tablets (Lipitor, Pfizer Pharmaceuticals Ltd., NMPA Approval No. H20051408), orally. 2) Lifestyle Intervention: A. Rational Diet: For post-PCI CHD patients undergoing combined aerobic-resistance exercise and EECP therapy, they were instructed to adhere to a low-salt, low-fat diet, consuming plenty of fresh vegetables, fruits, grains rich in dietary fiber and vitamins, along with adequate high-quality protein. This dietary regimen helps maintain normal vascular endothelial cell metabolism and provides solid nutritional support for exercise and EECP therapy, thereby better facilitating the combined intervention to improve vascular endothelial function and quality of life. B. Smoking Cessation and Alcohol Restriction: For these patients, healthcare providers reinforced health education regarding the dangers of smoking and alcohol, emphasizing how they impede the recovery of vascular endothelial function and compromise the efficacy of the combined therapy. Family members were also instructed to provide daily supervision to assist patients in strictly quitting smoking and limiting alcohol. C. Rest: These patients were advised to maintain healthy sleep patterns and ensure adequate rest. Sufficient rest promotes physical recovery and preserves energy reserves for the demands of exercise and EECP therapy. For patients with sleep disturbances, comprehensive nursing interventions (e.g., psychological counseling, sleep environment adjustments) were provided promptly to prevent sleep issues from hindering the improvement of vascular endothelial function and quality of life, thus ensuring the smooth implementation of the combined intervention. 3) Psychological Counseling: Psychological counseling was considered crucial during the intervention of combined aerobic-resistance exercise and EECP for post-PCI CHD patients. Patients were encouraged to maintain a positive and optimistic mindset, as this enhances adherence to the exercise and EECP therapy. Good adherence is a prerequisite for the combined therapy to effectively improve vascular endothelial function. Healthcare staff provided targeted guidance on self-regulation techniques (e.g., listening to music, communicating with others to relieve stress) and offered professional psychological counseling services. Promptly addressing negative emotions like anxiety and depression helps prevent the associated neuroendocrine disturbances from adversely affecting vascular endothelial function. This ensures the combined therapy can work more effectively to enhance the patient's quality of life.

Intervention：

On the basis of the intervention, the control group was given aerobic-resistance exercise training, 30min each time, 1-3h after meals, once every other day, 3 times a week for 12 weeks. 1. Preparation before intervention: an exercise group was established on wechat, and Tai chi, dumbbell exercises, and flexible balance exercises were distributed. Two professionals demonstrated and guided the exercises for the elderly. Those who do not arrive for special reasons need to complete the online video clocking. 2. Exercise process: The second stage, Taijiquan: The training was based on the Taijiquan movements created by the General Administration of Sports of China and combined with the video of Taijiquan (Standard version of the General Administration of Sports of China), once every 10 minutes, once a day, a total of 10 minutes. Dumbbell exercise (resistance exercise) : A single action repeat 8-10 times, divided into three groups to complete, 10 minutes. Dumbbells are adjustable dumbbells produced by famous sports equipment brands; The resistance was measured at 10RM, and the model was determined according to the actual product purchased. Flexibility balance exercise: to promote body relaxation, relieve muscle tension for the purpose of action can refer to professional sports relaxation tutorials, with soothing music to practice, 5 minutes 1 time, 2 times a day, a total of 10 minutes. (4) Exercise monitoring and precautions: 1) Vital signs should be measured before and after each Tai chi exercise, dumbbell exercise, and flexibility balance exercise. For patients with hypertension, if there is high blood pressure (BP>=160/100mmHg) or low blood pressure (BP < 90/60mmHg), tachycardia (HR > 100bpm) or irregular rhythm, Should not participate in any of the four sports; 2) During exercise, if the patient has shortness of breath, angina pectoris, dizziness, palpitation, chest tightness, shortness of breath or sweating, or physical activity discomfort during Tai Chi exercise, dumbbell exercise, and flexible balance exercise, the current exercise should be stopped immediately; 3) After completing Tai Chi, dumbbell exercises and flexibility balance exercises, it is not appropriate to eat immediately, pay attention to keep warm and avoid the occurrence of cold.

Intervention：

Implementation Method: EECP Therapy The EECP therapy was administered using the pneumatic external counterpulsation device (Model: P-ECT/T1) manufactured by Chongqing Pushikang Technology Development Co., Ltd. Pre-Treatment Preparation: Device Inspection: The operator comprehensively inspected the counterpulsation device. This included verifying secure power cord connections, smooth operation of the air pump, normal display of all parameters on the screen, and testing the inflation/deflation functions to ensure no sticking or delays. This confirmed the overall good operational status of the machine, establishing a foundation for treatment safety. Patient Preparation: Patients were guided to arrive at the treatment room 15-20 minutes in advance and were seated in a quiet and comfortable waiting area to rest. This prevented emotional tension or vital sign fluctuations due to rushing. Patients were explicitly instructed to empty their bladders. Those experiencing difficulty urinating were provided appropriate assistance to prevent discomfort caused by a full bladder during the procedure. Patient Positioning and Cuff Application: The patient was assisted into a supine position on the counterpulsation bed. Appropriately sized cuffs were selected based on the patient's limb dimensions. The air was completely expelled from the cuffs, which were then inspected for surface damage and secure connections to ensure no air leaks. The cuffs were sequentially wrapped around the patient's thighs, calves, and buttocks, ensuring a snug but comfortable fit—tight enough for close contact without causing pressure. The ECG lead was then switched to the "ECG" position. Once a clear ECG waveform was displayed on the monitor, the inflation knob was slowly adjusted to precisely set the inflation signal at the peak of the T-wave and the deflation signal at or just before the peak of the P-wave. This positioning was repeatedly verified to ensure synchronization of the counterpulsation with the cardiac cycle. Treatment and Monitoring: The counterpulsation ratio was accurately set to 1:1, synchronizing the counterpulsation frequency with the patient's heart rate to ensure each heartbeat was assisted by a corresponding counterpulsation. The inflation/deflation switch was activated first, followed by the air pump switch. The initial inflation pressure was set at a low level and gradually adjusted according to the patient's tolerance, ultimately maintaining a stable pressure between 0.030 - 0.045 MPa. Throughout the treatment, the operator remained beside the patient, closely observing their facial expressions and limb movements, regularly inquiring about any discomfort (e.g., distension, numbness), and simultaneously monitoring real-time changes in the ECG waveform on the screen to ensure the procedure progressed as planned. Treatment Cessation Procedure: At the end of the treatment, the following sequence was strictly followed: first turning off the air pump, then pressing the stop button, and finally switching off the inflation button. This prevented potential device damage or patient discomfort due to incorrect operational sequence. The ECG electrodes were then carefully removed, using gentle action to avoid skin irritation. For patients with sensitive skin, the electrode sites were wiped with warm water beforehand. The cuffs were loosened in sequence from the buttocks to the thighs and then the calves. During removal, the limbs were closely examined for marks, redness, swelling, or other abnormalities, and the patient was monitored for adverse reactions such as dizziness, palpitations, or muscle soreness, with appropriate measures taken promptly if any issues were identified. Implementation Method: EECP Therapy The EECP therapy was administered using the pneumatic external counterpulsation device (Model: P-ECT/T1) manufactured by Chongqing Pushikang Technology Development Co., Ltd. Pre-Treatment Preparation: Device Inspection: The operator comprehensively inspected the counterpulsation device. This included verifying secure power cord connections, smooth operation of the air pump, normal display of all parameters on the screen, and testing the inflation/deflation functions to ensure no sticking or delays. This confirmed the overall good operational status of the machine, establishing a foundation for treatment safety. Patient Preparation: Patients were guided to arrive at the treatment room 15-20 minutes in advance and were seated in a quiet and comfortable waiting area to rest. This prevented emotional tension or vital sign fluctuations due to rushing. Patients were explicitly instructed to empty their bladders. Those experiencing difficulty urinating were provided appropriate assistance to prevent discomfort caused by a full bladder during the procedure. Patient Positioning and Cuff Application: The patient was assisted into a supine position on the counterpulsation bed. Appropriately sized cuffs were selected based on the patient's limb dimensions. The air was completely expelled from the cuffs, which were then inspected for surface damage and secure connections to ensure no air leaks. The cuffs were sequentially wrapped around the patient's thighs, calves, and buttocks, ensuring a snug but comfortable fit—tight enough for close contact without causing pressure. The ECG lead was then switched to the "ECG" position. Once a clear ECG waveform was displayed on the monitor, the inflation knob was slowly adjusted to precisely set the inflation signal at the peak of the T-wave and the deflation signal at or just before the peak of the P-wave. This positioning was repeatedly verified to ensure synchronization of the counterpulsation with the cardiac cycle. Treatment and Monitoring: The counterpulsation ratio was accurately set to 1:1, synchronizing the counterpulsation frequency with the patient's heart rate to ensure each heartbeat was assisted by a corresponding counterpulsation. The inflation/deflation switch was activated first, followed by the air pump switch. The initial inflation pressure was set at a low level and gradually adjusted according to the patient's tolerance, ultimately maintaining a stable pressure between 0.030 - 0.045 MPa. Throughout the treatment, the operator remained beside the patient, closely observing their facial expressions and limb movements, regularly inquiring about any discomfort (e.g., distension, numbness), and simultaneously monitoring real-time changes in the ECG waveform on the screen to ensure the procedure progressed as planned. Treatment Cessation Procedure: At the end of the treatment, the following sequence was strictly followed: first turning off the air pump, then pressing the stop button, and finally switching off the inflation button. This prevented potential device damage or patient discomfort due to incorrect operational sequence. The ECG electrodes were then carefully removed, using gentle action to avoid skin irritation. For patients with sensitive skin, the electrode sites were wiped with warm water beforehand. The cuffs were loosened in sequence from the buttocks to the thighs and then the calves. During removal, the limbs were closely examined for marks, redness, swelling, or other abnormalities, and the patient was monitored for adverse reactions such as dizziness, palpitations, or muscle soreness, with appropriate measures taken promptly if any issues were identified.

Intervention：

1. The combination therapy group received an intervention comprising rehabilitative exercises (Tai Chi, dumbbell exercises, and flexibility/balance drills) combined with External Counterpulsation (EECP) therapy, in addition to the routine care given to the conventional group. The specific protocols for the exercises—including movement standards, session duration, and intensity requirements—as well as the EECP operation procedures, were consistent with those detailed in the previous descriptions for the respective standalone groups. 2. The rehabilitative exercises (Tai Chi, dumbbell exercises, and flexibility/balance drills) were scheduled every Monday, Wednesday, and Friday. The EECP therapy sessions were administered daily from Monday to Friday. Therefore, on the overlapping days (Monday, Wednesday, and Friday), the intervention sequence was strictly organized as follows: the cardiac rehabilitation exercises were conducted first. Upon their completion, patients were required to rest for at least 30 minutes to ensure their physiological state had stabilized. Subsequently, the EECP therapy session was initiated. This structured sequence ensured the orderly implementation of all interventions without interference, allowing each modality to exert its therapeutic effect fully.