Early Outcomes of Acute Type A Aortic Dissection Treatment According to the Stanford Classification During the COVID-19 Pandemic

Acute Stanford type A aortic dissection is a cardiovascular emergency that is extremely urgent, severe and complex. The mortality of non-surgically treated acute type A dissection was 47.3 ± 4.4%, 55.0 ± 4.4%, 76.7 ± 3.7% and 83.9 ± 4.3% at 24 hours, 48 hours, 14 days and 1 year, respectively.¹ The hourly mortality rate during the first 24 hours after symptom onset was 2.6%.¹

The first patient with this condition was described in medical literature by Nicholls in 1760, and later anatomically detailed by Morgagni in 1761.^2,3 In 1963, a case of Stanford type A aortic dissection was successfully diagnosed and surgically treated by Morris et al., opening a new era in the surgical treatment of this disease.⁴ In 2000, the mortality rate of aortic root surgery was 14.6%.⁵

In Vietnam, surgery for thoracic aortic disease in general (and acute Stanford type A aortic dissection in particular) has been routinely performed at major cardiovascular surgical centres nationwide for decades. Initially, the rate of complications and mortality was high, but with continuous improvements in surgical technique and better coordination among surgeons, anaesthesiologists, perfusionists and postoperative care teams, outcomes have gradually improved.

At Cho Ray Hospital, emergency surgery for this condition has been regularly performed for decades and has shown very promising outcomes. At one point, the rate of complications and mortality was reduced to single digits. However, during the COVID-19 pandemic, with numerous medical constraints such as limited access to healthcare services, transportation difficulties, staff shortages, and a lack of medical equipment and supplies, did these factors affect the treatment outcomes for this disease?

Methods

Setting

Cho Ray Hospital is a national, special-class tertiary care institution that serves as the final referral centre for the southern region of Vietnam. With a capacity exceeding 3,200 beds, the hospital provides comprehensive care for a wide range of critical and complex conditions. The Department of Cardiac Surgery performs more than 1,200 procedures annually. In southern Vietnam, there are approximately five cardiac surgery centres; however, only two, including Cho Ray Hospital, can perform aortic surgery.

Subjects

Patients who were diagnosed with acute Stanford type A aortic dissection and were surgically treated at the Cardiac Surgery Intensive Care Unit, Cho Ray Hospital, between January 2017 and December 2022, were enrolled in the study.

Patients were divided into two groups: Group A, all patients from January 2017 to December 2019 (before the COVID-19 pandemic); and Group B, all patients from January 2020 to December 2022 (during and after the COVID-19 pandemic).

Procedure

This was a retrospective case series study. Data were collected and processed using R software.

Results

Between January 2017 and December 2022, 325 patients underwent emergency surgery for acute Stanford type A aortic dissection at Cho Ray Hospital. Group A (pre-pandemic) consisted of 122 patients, while Group B (peri-/post-pandemic) consisted of 203 patients. Despite both groups covering a 3-year span, the number of cases nearly doubled during the pandemic period.

The mean age was similar between the cohorts: 54.26 ± 12.49 years in Group A and 54.89 ± 11.57 years in Group B. Male patients predominated in both groups, although their proportion was higher in Group A (72.13%) compared with Group B (62.4%; Table 1 ).

The surgical strategy shifted toward more complex interventions during the pandemic. Total aortic arch replacement was performed in 63.94% of Group A patients compared with 75.37% in Group B. Similarly, the use of concomitant stent-grafts via the frozen elephant trunk technique saw an increase from 9.83% in the pre-pandemic period to 37.93% during the pandemic.

These more extensive repairs were reflected in the operation duration. The mean cardiopulmonary bypass time was significantly longer in Group B at 240.03 ± 77.59 minutes, compared with 218.46 ± 80.15 minutes in Group A (p=0.018). Aortic cross-clamp times also showed an upward trend, increasing from 133.86 ± 72.09 minutes in Group A to 147.016 ± 61.08 minutes in Group B (p=0.09; Table 2 ).

Early outcomes demonstrated a marked difference in complications and survival between the two periods. The mortality rate nearly doubled from 7.34% in Group A to 15.27% in Group B (p=0.053; Table 3). Furthermore, the incidence of reoperation for bleeding was significantly higher in the pandemic cohort, rising from 9.83% in Group A to 24.63% in Group B (p=0.002).

In contrast, the rate of postoperative stroke remained stable between the two groups, recorded at 9.83% in Group A and 10.83% in Group B (p=0.92). Additionally, tracheostomy was required in 12.31% of the patients in Group B (Table 3 ).

Discussion

Preoperative Patient Characteristics

Although both groups were studied over the same 3-year span, Group A had only 122 patients while Group B, during the COVID-19 pandemic (2020–2022), had 203; almost double the number. The significant increase in cases during this time at Cho Ray Hospital may have been due to limited access to healthcare, resulting in poor blood pressure control and thus a higher incidence of aortic dissection.

The mean age was similar between the groups: 54.26 ± 12.49 years in Group A and 54.89 ± 11.57 years in Group B. Male patients outnumbered female patients in both groups, with a male : female ratio of 2–3:1. These figures suggest that although the number of cases increased during the pandemic, the age and gender distributions remained unchanged.

Surgical Approach

While the overall surgical approaches were comparable between the two periods, Group B had a higher rate of total arch replacement and concomitant stent-graft use. In our earlier cohort (Group A), no significant difference in outcomes was observed between the patients undergoing arch replacement and those who did not, which may have encouraged a trend toward more extensive or aggressive surgical strategies. Alternatively, the greater extent of arch and stent procedures during the pandemic period could indicate that patients presented with more advanced disease requiring complex repair.

Furthermore, the longer cardiopulmonary bypass and aortic cross-clamp times recorded during the pandemic are likely to reflect increased procedural complexity or challenges associated with resource limitations. Comparable findings were reported by Fukuhara et al. in 2020 and Kaplan et al. in 2023, who noted that both case severity and perioperative logistics were adversely affected by pandemic-related constraints in tertiary cardiac centres.^6,7

Early Postoperative Outcome

Despite the increase in total arch replacement in Group B, the stroke rate remained similar: 9.83% in Group A versus 10.83% in Group B (p=0.92), suggesting that modern neuroprotection techniques effectively mitigated stroke risk.

However, the rates of reoperation for bleeding and mortality in Group A versus Group B more than doubled: reoperation 9.83% versus 24.63% (p=0.002), and mortality 7.34% versus 15.27% (p=0.053). Although the mortality difference did not reach statistical significance, the near doubling remains clinically important and aligns with findings from other centres during the pandemic.⁷

The data from the International Registry of Acute Aortic Dissection study in 2016, based on 17 years of research involving 4,428 patients with acute Stanford type A aortic dissection treated surgically, reported an in-hospital mortality rate ranging from 17% to 26%, depending on the centre.⁸ Looking at these data, we can conclude that the mortality rate of 15.27% in the treatment of this condition is not a disappointing figure. However, the increase in mortality during surgery and reoperation for this condition during the COVID-19 pandemic period was significant. This could be attributed to several factors. Studies from the US and China have also reported similar outcomes, which could be due to patients being diagnosed later when the disease had progressed, or due to suboptimal treatment conditions during the pandemic.^6,7

Delayed Presentation and Diagnosis

Travel restrictions, fear of infection, and limited access to healthcare during the pandemic caused many patients to present later, with more advanced dissections requiring extensive repairs such as total arch replacement.

More Complex Surgical Cases

Longer cardiopulmonary bypass and cross-clamp times, together with a higher proportion of total arch replacements in Group B, suggested more severe disease and technically demanding procedures, which inherently increased the bleeding and mortality risks.

Healthcare System Constraints

Redeployment and illness of intensive care unit and surgical staff, shortages of supplies and blood products, and transportation challenges all reduced surgical efficiency and delayed emergency care, contributing to higher rates of reoperation and mortality.

Moreover, the cardiopulmonary bypass time was significantly longer in Group B (240.03 ± 77.59 minutes) than in Group A (218.46 ± 80.15 minutes, p=0.018), suggesting that surgery during the pandemic period was more complex and time-consuming. The aortic cross-clamp time also increased (147.02 ± 61.08 versus 133.86 ± 72.09 minutes, p=0.09), showing a similar trend although not statistically significant. These findings are likely to reflect more extensive disease, more challenging surgical indications, and reduced team coordination during the pandemic.

Nevertheless, the incidence of stroke did not increase correspondingly (p=0.92), indicating that cerebral protection strategies remained effective. This is a positive sign, suggesting that advancements in technique and improvements in procedural protocols, especially in complex procedures such as aortic arch replacement, have been effective.

Conclusion

Acute Stanford type A aortic dissection is a serious surgical emergency with very high mortality and complication rates if not treated promptly.

During the COVID-19 pandemic, the number of patients with acute aortic dissection treated at Cho Ray Hospital increased significantly. At the same time, mortality and complications, such as postoperative bleeding, also rose, even though surgical technique and cerebral protection strategy were maintained and improved.

While there are no further studies to fully assess the causes of the increased complication and mortality rates during the COVID-19 period, the difficulties in accessing healthcare services during the pandemic made it harder for patients to manage blood pressure, leading to delays in diagnosis and surgery. These delays could significantly increase the rates of complications and mortality.

To improve outcomes in future crises, healthcare systems should ensure timely access to emergency surgery for acute aortic syndromes, maintain continuity of hypertension management through community or telemedicine services, and strengthen the preparedness of surgical teams and essential supplies to prevent treatment delays.