第一部分：择期成人心脏外科手术患者术前新型冠状病毒感染状况抽样调查的初步分析

【目的】对拟行择期心脏外科手术的成人患者近期新型冠状病毒感染情况进行抽样调查及初步分析。

【方法】随机抽取本院2023年2月6日至2023年3月8日拟行择期心脏外科手术的成人患者，通过术前访视对患者术前新冠病毒感染情况进行问卷调查，并从电子病例中提取临床资料，对近期感染新型冠状病毒患者进行初步分析。【结果】2023年2月6日至2023年3月8日共1343例住院患者拟行择期心脏外科手术。本调查共收回有效问卷516份，其中近期感染新型冠状病毒的患者共427例，患者平均年龄为58.0±11.1岁，女性116例（27.2%）。患者新冠感染确诊至手术的中位时间为68（58，79）天。感染期间最常见的症状是发热（77.0%）。120例（28.1%）患者表示新冠感染后已患的心血管疾病症状明显加重。女性患者在心血管症状加重组的占比显著高于无心血管症状加重组（36.7% vs. 23.5%，P = 0.006）。感染时间在2023年1月8日之后的患者在心血管症状加重组的例数显著高于无心血管症状加重组（6.7% vs. 2.6%, P = 0.047）；新冠感染期间存在症状≥ 5项在心血管症状加重组例数显著高于无心血管症状加重组（46.7% vs. 17.6%, P < 0.001）。

【结论】大多数拟行择期心脏外科手术的成人患者在感染新冠病毒后康复良好。有少数患者感染后心血管疾病加重，需要更谨慎的术前评估来确定手术风险和潜在并发症。

第二部分：近期新型冠状病毒感染后择期心脏外科手术时机的选择：单中心回顾性队列研究

【目的】评估近期新冠病毒感染后择期体外循环下心脏外科手术的安全性，并探讨手术的最佳时机。【方法】采用回顾性队列研究设计，纳入了2023年2月7日至3月9日接受择期体外循环下心脏外科手术的近期新冠病毒感染的成年患者。根据感染至手术的间隔时间，将患者分为术前新冠病毒感染≤ 8周和> 8周两组，比较临床资料和术后结局。采用多元线性回归、亚组分析及敏感性分析探讨影响患者结局的相关因素。【结果】共纳入415例患者，其中79例（19.0%）术前新冠病毒感染≤ 8周。≤ 8周组的患者表现出较长的机械通气时间[7（5，11）h vs. 6（5，8）h，P = 0.02]、术后胸腔引流总量增加[961（680，1405）mL vs. 800（533，1102）mL，P = 0.003]、重症监护室住院时间[48（24，72）h vs. 24（24，48）h，P = 0.012]和住院时间[13（10，15）d vs. 11（9，14）d，P = 0.041]延长。对于60岁及以上患者的重症监护室住院时间和住院时长的影响更大。【结论】大多数患者可以在新冠病毒感染后安全地进行择期体外循环下心脏手术。8周内新冠病毒感染可能与患者延长的ICU时间和住院时间相关联。

Chapter 1 Preliminary analysis of sampling survey on preoperative COVID-19 infection status in adult patients scheduled for elective cardiac surgery【OBJECTIVES】To conduct a sampling survey and preliminary analysis of recent COVID-19 infection in adult patients scheduled for elective cardiac surgery. 【METHODS】Adult patients scheduled for elective cardiac surgery from February 6, 2023 to March 8, 2023 were randomly selected. Patients’ preoperative COVID-19 infection status was surveyed through preoperative interviews, and clinical data were extracted from electronic medical records. Analysis was conducted on patients who had recently infected with COVID-19. 【RESULTS】During the study period, a total of 1343 adult patients scheduled for elective cardiac surgery. A total of 516 valid questionnaires were collected in this survey, among which there were 427 cases of recent COVID-19 infection. The mean age of these patients was 58.0 ± 11.1 years, and 116 cases (27.2%) were female. The median interval from COVID-19 infection to cardiac surgery was 68 (58, 79) days. The most common symptoms reported during the infection period were fever (77.0%). One hundred twenty patients (28.1%) patients reported a significant exacerbation of cardiovascular symptoms after COVID-19 infection. Female patients in the group of exacerbation of cardiovascular symptoms had a significantly higher proportion than those without exacerbation of cardiovascular symptoms (36.7% vs. 23.5%, P = 0.006). In the exacerbation of cardiovascular symptoms group, more patients were infected after January 8, 2023, and had ≥ 5 types of symptoms compared to those without exacerbation of cardiovascular symptoms (6.7% vs. 2.6%, P = 0.047, 46.7% vs. 17.6%, P < 0.001; respectively). 【CONCLUSIONS】Most adult patients scheduled for elective cardiac surgery recover well after contracting the COVID-19. However, a small number of patients experience exacerbation of cardiovascular symptoms following the infection, necessitating a more cautious preoperative assessment to determine surgical risks and potential complications.

Chapter 2 Timing of elective cardiac surgery following recent COVID-19 infection: a single-center retrospective cohort study

【OBJECTIVES】This study aimed to evaluate the safety of elective on-pump cardiac surgery after COVID-19 infection and explore the optimal timing for the procedure. 【METHODS】A retrospective cohort study was conducted in adult patients who underwent elective on-pump cardiac surgery between February 7th, 2023, and March 9th, 2023. Patients who had preoperatively infected with COVID-19 were included. Patients were categorized into preoperative COVID-19 ≤ 8 weeks and > 8 weeks groups. Surgical parameters and postoperative outcomes were compared. Multiple linear regression, subgroup analysis and sensitivity analysis were used to determine the associated factors of patients’ outcomes. 【RESULTS】A total of 415 patients were included, with 79 (19.0%) having a preoperative COVID-19 diagnosis ≤ 8 weeks. In preoperative COVID-19 ≤ 8 weeks group, patients exhibited longer mechanical ventilation (MV) time (7 (5，11) h vs. 6 (5, 8) h, P=0.02), increased postoperative drainage volume (961 (680, 1405) mL vs. 800 (533, 1102) mL, P = 0.003), longer length of stay in the intensive care unit (LOS ICU) (48 (24, 72) h vs. 24 (24, 48) h, P =0.012) and LOS (13 (10, 15) d vs. 11 (9, 14) d, P = 0.041) compared to preoperative COVID-19 > 8 weeks group. The effects of preoperative COVID-19 infection ≤ 8 weeks on ICU LOS and LOS were greater in patients aged 60 and older.【CONCLUSIONS】Most patients can safely undergo elective on-pump cardiac surgery after COVID-19 infection. COVID-19 infection within 8 weeks may be associated with patient extended ICU LOS and LOS.