Previous cardiovascular surgery significantly increases the risk of developing critical illness in patients with COVID-19

To the editor,

We read with great interest the article by Dr. Galloway JB and colleagues recently published in the Journal of Infection entitled “A clinical risk score to identify patients with COVID-19 at high risk of critical care admission or death: An observational cohort study”.¹ Early identification of patients with high-risk of poor prognosis may facilitate the provision of timely supportive treatment in advance and reduce the mortality of patients. In this study, the authors identified several comorbidities as risk factors of worse outcomes of COVID-19 patients, including diabetes, hypertension, and chronic lung disease. However, little is known about the impact of previous surgery on COVID-19. Herein, we evaluated whether COVID-19 patients with previous surgery are at high-risk of critical illness.

We conducted a multicenter study focusing on the clinical characteristics of COVID-19 patients with previous surgery in six designated hospitals in the Hubei and Guangdong provinces, China. COVID-19 was diagnosed according to the WHO interim guidance. 461 patients with COVID-19 that hospitalized from January 1 to March 31, 2020 were enrolled. We collected demographics, comorbidities, laboratory variables, and chest CT images from medical records. We defined the severity of COVID-19 according to the newest COVID-19 guidelines of China² and the guidelines of American Thoracic Society for community-acquired pneumonia.³ Critical illness is defined as meeting at least one of the following criteria: respiratory failure requiring mechanical ventilation, shock, intensive care unit (ICU) admission, or death. According to surgical sites, previous surgeries were categorized into cardiovascular surgery, skeletal surgery, urogenital surgery, head and neck surgery, gastrointestinal surgery and others. Baseline features were compared between patients with and without previous surgery. To identify risk factors for critical illness, baseline variables with p < 0.10 in univariable analysis were entered into multivariate logistic regression. Time from diagnosis of COVID-19 to death was explored using Kaplan-Meier survival analysis. Considering in-hospital death is competing risk of ICU admission, time from diagnosis of COVID-19 to ICU admission was analyzed by a competing-risk model. Our institutional ethics review board approved the study and waived the need for informed consent.

In total, 47 (10.2%) COVID-19 patients with previous surgery. Gastrointestinal surgery was the most frequent surgery type (19/47, 40.4%), followed by cardiovascular surgery (11/47, 23.4%), urogenital surgery (10/47, 21.3%), skeletal surgery (7/47, 14.9%), and head and neck surgery (6/47, 12.8%). COVID-19 patients with previous surgery had obviously worse outcomes (p < 0.001). Compared with patients who had no previous surgery, patients had previous surgery were older (p < 0.001), had higher rate of hypertension (p = 0.039), coronary heart disease (p = 0.002), diabetes (p = 0.017), and chronic lung disease (p = 0.020), lower lymphocyte (p = 0.001) and albumin (p = 0.022), and higher aspartate aminotransferase (p = 0.013) and high-sensitivity C-reactive protein (p = 0.011) (Supplementary Table 1). Among various surgery types, only previous cardiovascular surgery was an independent risk factors of developing critical illness (odds ratio [OR] = 12.0, 95% CI: 2.1–69.6, p = 0.006) (Table 1 ). After adjusting for age, sex, and other comorbidities, the OR was 11.6 (95% CI: 2.7–49.6, p = 0.001). Patients with previous cardiovascular surgery had significantly worse survival (p = 0.001) and higher cumulative incidence of ICU admission (p < 0.001) than those patients without previous cardiovascular surgery (Supplementary Fig. 1).

Table 1.

Identification of risk factors of critical illness in COVID-19 patients using univariable and multivariable logistic regression.

	Univariable		Multivariable
	OR (95% CI)	P value	OR (95% CI)	P value
Age (years)	1.075 (1.054, 1.096)	<0.001	1.053 (1.022, 1.085)	0.001
Male	1.728 (1.031, 2.896)	0.038	1.178 (0.493, 2.814)	0.713
Comorbidities
Hypertension	3.650 (2.133, 6.244)	<0.001	1.966 (0.831, 4.648)	0.124
Coronary heart disease	2.992 (1.271, 7.043)	0.012	0.382 (0.096, 1.526)	0.173
Diabetes	3.804 (1.981, 7.302)	<0.001	1.205 (0.404, 3.590)	0.738
Chronic liver diseases	1.054 (0.296, 3.759)	0.935
Chronic lung diseases	1.970 (0.839, 4.626)	0.119
Types of previous surgery
Gastrointestinal surgery	2.372 (0.873, 6.446)	0.090	1.287 (0.297, 5.567)	0.736
Head and neck surgery	5.067 (1.003, 25.586)	0.050	5.785 (0.735, 45.534)	0.095
Urogenital surgery	2.149 (0.543, 8.498)	0.276
Skeletal surgery	6.847 (1.501, 31.228)	0.013	1.946 (0.205, 18.438)	0.562
Cardiovascular surgery	9.342 (2.665, 32.747)	<0.001	11.998 (2.068, 69.612)	0.006
Others	—	0.999
Laboratory findings
WBC (× 109/L)	1.223 (1.122, 1.334)	<0.001	1.015 (0.458, 2.252)	0.971
Neutrophil (× 109/L)	1.305 (1.190, 1.432)	<0.001	1.136 (0.505, 2.552)	0.758
Lymphocyte (× 109/L)	0.129 (0.067, 0.248)	<0.001	0.982 (0.288, 3.342)	0.977
LDH (U/L)	1.010 (1.007, 1.012)	<0.001	1.009 (1.005, 1.013)	<0.001
Hemoglobin (g/L)	1.002 (0.989, 1.015)	0.812
Platelet (g/L)	0.994 (0.990, 0.997)	0.001	0.994 (0.988, 1.000)	0.051
Albumin (g/L)	0.827 (0.783, 0.873)	<0.001	1.039 (0.929, 1.161)	0.507
AST (U/L)	1.029 (1.017, 1.041)	<0.001	1.002 (0.984, 1.020)	0.851
ALT (U/L)	1.004 (0.996, 1.011)	0.344
DBIL (μmol/L)	1.176 (1.078, 1.284)	<0.001	1.151 (1.004, 1.319)	0.043
IBIL (μmol/L)	0.932 (0.873, 0.994)	0.032	0.893 (0.771, 1.035)	0.133
TBIL (μmol/L)	1.016 (0.986, 1.046)	0.299
APTT (s)	1.017 (0.979, 1.058)	0.381
PT (s)	1.038 (0.996, 1.081)	0.080	1.038 (1.000, 1.077)	0.053
d-dimer (μg/ml)	1.002 (0.999, 1.004)	0.285
Creatinine (μmol/L)	1.023 (1.012, 1.034)	<0.001	1.006 (0.994, 1.018)	0.325
hs-CRP (mg/L)	1.013 (1.007, 1.019)	<0.001	0.991 (0.981, 1.000)	0.062
Procalcitonin (ng/ml)	1.124 (1.036, 1.220)	0.005	1.043 (0.929, 1.173)	0.475
Urea nitrogen (mmol/L)	1.316 (1.206, 1.435)	<0.001	1.191 (1.056, 1.343)	0.005
FBG (mmol/L)	0.953 (0.887, 1.024)	0.188
CT score	0.953 (0.887, 1.024)	0.188

Abbreviations: OR, odds ratio; CI: confidence interval; WBC, white blood cells; LDH, lactate dehydrogenase; AST, aspartate aminotransferase; ALT, alanine aminotransferase; TBIL, Total Bilirubin; DBIL, Direct Bilirubin; IBIL, indirect bilirubin; APTT, activated partial thromboplastin time; PT, prothrombin time; hs-CRP, high-sensitivity C-reactive protein; FBG, fasting blood glucose. A semiquantitative CT scoring system was designed to assess the involvement degree or area of pneumonia for each lung lobe (total 5 lung lobes): 0 for 0% involvement; 1 for 1–25% involvement; 2 for 26–50% involvement; 3 for 51–75% involvement; 4 for 76–100% involvement. A CT score (range, 0–20) was assigned by summarizing for the total scores of five lobes. CT images were reviewed independently by two radiologists with >10 years of experience.

To our best of knowledge, this is the first study that showed that patients with previous cardiovascular surgery instead of other surgeries significantly increase the risk of developing critical illness among patients with COVID-19.

Close attention should be paid to this population. High-level monitoring and aggressive treatment may be necessary to improve the outcomes of these patients.

Declaration of Competing Interest

None.