Suspected Mesenteric Malperfusion in Acute Type A Aortic Dissection During Pregnancy: A Case Report and Review of Reperfusion‐First Strategies

ABSTRACT

Aortic dissection during pregnancy is rare but potentially catastrophic. Acute Type A aortic dissection generally requires urgent surgical repair. When visceral malperfusion is present, however, the optimal sequence of interventions may be complex, particularly when pregnancy and recent cesarean delivery increase operative risk. Endovascular reperfusion followed by delayed aortic repair has been proposed in selected patients, although evidence supporting this strategy in pregnancy remains limited. A 37‐year‐old woman at 31 weeks' gestation presented with chest and back pain. Initial CT pulmonary angiography (CTPA) performed for suspected pulmonary embolism excluded pulmonary embolism but demonstrated marked aortic root dilatation measuring 6.7 × 5.4 cm. Before definitive aortic imaging could be obtained, she developed acute respiratory deterioration and fetal distress, prompting emergency cesarean delivery under general anesthesia. Postoperatively, transthoracic echocardiography demonstrated severe aortic root and ascending aortic dilatation, severe aortic regurgitation, reduced left ventricular ejection fraction, and a dissection flap consistent with Type A aortic dissection. Because of concern for catastrophic hemorrhage associated with cardiopulmonary bypass and hypothermic circulatory arrest shortly after cesarean delivery, definitive aortic repair was deferred for approximately 24 h while the patient underwent medical optimization. During this interval, she developed progressive metabolic acidosis and worsening renal function, raising clinical concern for visceral malperfusion. Dedicated abdominal vascular imaging was not obtained, and therefore the presence, distribution, and mechanism of mesenteric malperfusion could not be anatomically confirmed before surgery. At subsequent operative exploration, extensive small‐ and large‐bowel necrosis and markedly hypoperfused adnexal tissue were identified, precluding definitive aortic repair. The patient subsequently died after transition to comfort‐focused care. In an analysis from the International Registry of Acute Aortic Dissection, mesenteric malperfusion was associated with higher in‐hospital mortality than dissection without malperfusion. This case highlights the diagnostic and management challenges of acute Type A aortic dissection during pregnancy. In a pregnant patient presenting with chest or back pain and marked aortic root dilatation on PE‐protocol imaging, acute aortic syndrome should prompt urgent evaluation of the entire aorta. Progressive metabolic acidosis, renal dysfunction, or unexplained clinical deterioration should raise concern for visceral ischemia. Although reperfusion‐first strategies have been described in selected patients with aortic dissection and mesenteric malperfusion, their applicability in pregnancy remains uncertain and depends on defined vascular anatomy and the mechanism of malperfusion.

Key Clinical Message

In pregnant patients with chest or back pain and marked aortic root dilatation, acute aortic syndrome warrants evaluation of the entire aorta. Acidosis or renal dysfunction should raise concern for visceral ischemia. Reperfusion‐first strategies may benefit selected patients with confirmed malperfusion and suitable anatomy, but evidence in pregnancy remains limited.

1. Introduction

Aortic dissection is characterized by a tear in the intimal layer of the aorta, leading to the formation of a false lumen. This abnormal channel allows blood to flow between the layers of the aortic wall resulting in aneurysms, ruptures, and devastating complications. Aortic dissections are classified into two main types: Stanford Type A involves the ascending aorta and may extend to the descending aorta, while Stanford Type B is confined to the descending aorta distal to the left subclavian artery. Type A dissections carry an imminent risk for aortic rupture, and thus require emergent surgical repair, as untreated cases are associated with a mortality rate of 1%–2% per hour during the first 24 h [1, 2]. In contrast, Type B dissections can often be managed pharmacologically with beta‐blockers or vasodilators [1].

Aortic dissection in pregnancy is rare, occurring in only 0.0004% of pregnancies [3]. Unfortunately, in most cases, pregnancy‐related aortic dissections are caused by an underlying, yet undiagnosed, aortopathy [3]. They typically present acutely as a catastrophic event with severe tearing chest or back pain. Risk factors include hypertension and pregnancy‐related physiological and hormonal changes such as increased blood volume, elevated cardiac output, and high estrogen levels, which can suppress the synthesis of collagen and elastin, thereby weakening the vascular walls [4]. Inherited connective tissue disorders, including Marfan syndrome, Turner syndrome, and Ehlers‐Danlos syndrome, further heighten this risk [4].

Malperfusion of aortic branch vessels such as mesenteric arteries, a condition referred to as mesenteric malperfusion syndrome, may occur in 25%–30% of Type A aortic dissections and correlate with early mortality [5]. The diagnosis of malperfusion relies on a combination of clinical, laboratory, and radiologic findings. In addition to the classical aortic dissection symptoms, these patients may have bloody diarrhea, elevated lactate, and metabolic acidosis [6]. Imaging may demonstrate reduced or absent flow in mesenteric vessels, branch‐vessel obstruction, or other findings consistent with visceral malperfusion [6]. For patients with mesenteric malperfusion, the potential for bowel necrosis and progression to septic shock represents a major threat. Although immediate open central aortic repair remains the standard treatment for acute Type A aortic dissection, outcomes are substantially worse when complicated by mesenteric malperfusion. Historical series have reported mortality rates as high as 60%–75%, particularly among patients with established mesenteric ischemia and bowel necrosis [7]. More recent pooled data suggest an overall in‐hospital mortality of approximately 43.5% among patients with acute Type A aortic dissection complicated by mesenteric malperfusion, including approximately 40.3% among those undergoing central aortic repair as the initial strategy [7].

An alternative approach involving endovascular reperfusion before definitive central aortic repair has been proposed for carefully selected patients with acute Type A aortic dissection and mesenteric malperfusion [8]. The rationale and technique depend on the mechanism of malperfusion, which may result from dynamic obstruction, static branch‐vessel involvement, or a combination of both. However, evidence supporting this strategy remains limited and is derived predominantly from observational studies in nonpregnant populations.

Here, we describe a case of pregnancy‐related Type A aortic dissection with clinically suspected mesenteric malperfusion and extensive bowel ischemia. Despite an initial two‐stage management strategy consisting of cesarean delivery followed by planned delayed aortic repair, the patient developed extensive bowel necrosis that was ultimately incompatible with life. The case highlights the diagnostic challenges of mesenteric malperfusion in pregnancy and the complexity of balancing obstetric, aortic, and visceral considerations in determining the sequence of interventions.

2. Case History and Examination

The patient was a 37‐year‐old woman, gravida 4 para 3, at 31 weeks' gestation, 170 cm tall and weighing 117.3 kg, with a body mass index of 40.5 kg/m². She reported no complications during her previous pregnancies. Her surgical history was notable for a right inguinal hernia repair. Her medications included prenatal vitamins and iron supplements. She had limited prenatal care. Family history was notable for a 17‐year‐old daughter with an unspecified cardiac condition treated with losartan and a father who died suddenly of an unspecified cause.

At 6:30 p.m., the patient presented to the emergency department with chest and back pain and intermittent shortness of breath while driving home from an obstetric appointment. Initial vital signs were heart rate 79 beats per minute, respiratory rate 19 breaths per minute, blood pressure 152/72 mmHg, and oxygen saturation 97% on room air. She was alert and oriented without apparent respiratory distress. Breath sounds were normal. Examination was notable for a gravid abdomen and bilateral lower‐extremity edema. Laboratory testing was unremarkable except for a potassium level of 2.7 mmol/L and glucose of 156 mg/dL.

3. Methods/Differential Diagnosis/Treatment

A chest computed tomography pulmonary angiography (CTPA) was obtained by the emergency department. The CTPA showed no evidence of pulmonary embolism but revealed marked aortic root dilatation measuring 6.7 × 5.4 cm (Figures 1 and 2). The CTPA was limited to the chest and therefore did not adequately visualize the abdominal aorta. Given the patient's symptoms and marked aortic root dilatation, further evaluation of the entire aorta was warranted; however, no dedicated aortic computed tomography angiography (CTA) or definitive imaging of mesenteric branch‐vessel involvement was obtained at that time. The OB/GYN, cardiology, and cardiothoracic surgery team were consulted by the emergency department, and the patient was sent to the labor and delivery floor after her CT scan. At the time of evaluation by the OB team, the patient's vital signs were stable; however, she was experiencing an extreme amount of pain. Intravenous (IV) morphine was given for pain. The surgery team recommended the patient be admitted to the intensive care unit (ICU) for pain management and blood pressure control. However, since the patient was still in a significant amount of pain, it was then decided by OB/GYN that it would be best to transfer the patient to a tertiary care center with a higher level of care. In the process of attempting transfer, the patient was noted to rapidly decompensate with oxygen saturation dropping to 70–80s, worsening shortness of breath and chest pain, tachycardia, and hypertension. Rapid response was called; there were decreased fetal heart tones noted. A clinical decision was made for emergency cesarean section to salvage the fetus.

FIGURE 1.

Axial chest computed tomography pulmonary angiography (CTPA) with pulmonary embolism protocol upon hospital arrival. CTPA showed a significant prominence for aortic root measuring 6.7 × 5.4 cm (arrow).

FIGURE 2.

Coronal chest tomography scan view showing the dilated aorta (arrow).

At 9:38 p.m., the patient became obtunded upon arrival to the operating room, while her skin was noted to be dusky blue, oxygen saturation was 65%, increasing slightly to 70% when preoxygenated. General anesthesia with rapid sequence intubation using video laryngoscopy was complicated by massive pulmonary edema that obscured the vocal cords. A regular 3.5 laryngoscope was used with suction to visualize airway anatomy. Following successful intubation, oxygen saturation increased to 100% and a left radial arterial line was placed. A living baby boy was delivered 18 min later. The male neonate was transferred to the neonatal intensive care unit following delivery. Additional neonatal outcome data were not available to the authors. The patient remained hemodynamically stable throughout surgery with an estimated blood loss of 400 mL and urine output of 300 mL. After cesarean delivery, the patient remained intubated and was transported to the ICU.

Around midnight, the patient arrived in the ICU, where a multidisciplinary team including cardiothoracic surgery, anesthesiology, obstetrics and gynecology, and critical care evaluated her. Bedside TTE demonstrated an ejection fraction of 35%–40%, severe aortic regurgitation, severe aortic root dilatation measuring 6.4 cm, a dissection flap at the sinotubular junction, and ascending aortic dilatation measuring 5.9 cm. Arterial blood gas analysis (ABG) demonstrated significant acidemia (pH 7.18, PaCO₂ 52 mmHg, HCO₃ 19 mmol/L, base excess −9 mmol/L). Lactic acid was 16.9 mmol/L. Despite these metabolic abnormalities, she initially remained hemodynamically stable with palpable peripheral pulses and no vasopressor requirement.

Although urgent operative repair is generally indicated for acute Type A aortic dissection, the cardiothoracic surgical team elected to defer repair for approximately 24 h because cardiopulmonary bypass and hypothermic circulatory arrest shortly after cesarean delivery were considered to carry a substantial risk of catastrophic hemorrhage. The immediate plan was medical optimization, including blood pressure control and correction of metabolic abnormalities. By approximately 5:00 a.m., however, the patient had developed progressive metabolic acidosis (lactate of 18.8 mmol/L from 16.9 mmol/L), shocked liver (AST > 7500 and ALT 7047) and worsening renal function (creatinine 2.8 mg/dL from 0.6 mg/dL) with no urine output despite ongoing medical management. These findings raised clinical concern for evolving visceral malperfusion, although dedicated abdominal vascular imaging had not been obtained and the presence or mechanism of mesenteric malperfusion could not be anatomically confirmed at that time.

The multidisciplinary team planned an emergency hysterectomy in an effort to reduce the anticipated risk of uterine hemorrhage during subsequent aortic surgery requiring cardiopulmonary bypass. Around 11:00 a.m., the patient was brought to the operating room. Intraoperative transesophageal echocardiography (TEE) confirmed a severely dilated left ventricle, ejection fraction 35%–40%, severe aortic insufficiency, proximal ascending aortic aneurysm measuring 6.7 cm, aortic dissection flap seen beginning at the sinotubular junction and extending to the descending aorta, consistent with a Type A dissection of the aorta (Figure 3). When the abdomen was opened for the hysterectomy to be done, the necrotic bowel was visualized. The hysterectomy was completed at the same time general surgery was awaiting in the room to assess the bowel. Extensive necrosis from the mid‐jejunum to the terminal ileum and the cecum to the mid‐descending colon was identified, with marked hypoperfusion of the adnexal tissue. Given the extent of intestinal necrosis and the overall clinical condition, the operative findings were considered nonsurvivable, and definitive aortic repair was not pursued.

FIGURE 3.

Transesophageal echocardiogram shows aortic dissection flap (D) seen in ascending aorta, aortic arch, as well as descending aorta. Dissection flap (D) appears to begin at the level of the sinotubular junction. True lumen diameter (TL) is significantly smaller than false lumen (FL).

4. Outcome

After a discussion among all the specialists in the case, the decision was made not to proceed with the aortic repair since findings were considered nonsurvivable. The patient remained intubated and was transported back to the ICU. Neurological assessment demonstrated pinpoint pupils and absence of brainstem reflexes. In accordance with the family's wishes, the patient was placed on hospice, terminal extubation was performed, and the patient expired shortly after (Table 1).

TABLE 1.

Clinical timeline.

Time	Event	Key findings
6:30 p.m.	ED presentation	Chest/back pain and intermittent dyspnea; SpO2 97% on room air
Initial evaluation	CTPA performed	No PE; aortic root dilatation 6.7 × 5.4 cm
Later evening	Acute deterioration	Worsening dyspnea and chest pain; SpO2 70–80s; fetal distress
9:38 p.m.	Emergency cesarean delivery	General anesthesia; pulmonary edema during intubation; live male infant delivered
~Midnight	ICU evaluation	TTE: Type A dissection, severe AR, aortic root 6.4 cm, EF 35%–40%; pH 7.18
Overnight	Medical optimization	Aortic repair deferred because of concern for hemorrhage after recent cesarean delivery
~5:00 a.m.	Clinical deterioration	Progressive metabolic acidosis and worsening renal function; concern for visceral malperfusion
~11:00 a.m.	Operative exploration	TEE confirmed Type A dissection; extensive bowel necrosis identified
After exploration	Definitive repair abandoned	Findings considered nonsurvivable
Outcome	Comfort‐focused care	Terminal extubation; patient died shortly thereafter

5. Discussion

The management for acute aortic dissection in pregnancy is based on the type of dissection and gestational age. For type A dissection occurring before 28 weeks of gestation, urgent surgical repair with aggressive fetal monitoring or termination of pregnancy is preferred, with maternal survival being prioritized [1]. For Type A dissection occurring after 28 weeks, an urgent cesarean section followed by aortic repair is recommended when clinically appropriate. This approach can be carried out using one of two strategies: a two‐stage approach, in which cesarean delivery is performed first and aortic repair is delayed by 24 h, or a single‐stage approach, in which both procedures are performed simultaneously [1]. The two‐stage approach has been associated with a 14.3% maternal mortality rate and a 0% fetal mortality rate, while the single‐stage approach resulted in a 16.7% maternal mortality rate and a 33.3% fetal mortality rate [1].

The initial diagnostic evaluation in the emergency room focused on pulmonary embolism, and CTPA was performed rather than imaging of the entire aorta. Although the CTPA excluded pulmonary embolism, it demonstrated marked aortic root dilatation in a symptomatic patient, warranting further evaluation of the entire aorta. Because no abdominal CTA was obtained, the presence and mechanism of mesenteric malperfusion could not be established before clinical deterioration. By the early morning, mesenteric ischemia was suspected clinically as her metabolic acidosis and renal function worsened but could not be characterized radiographically; extensive bowel ischemia and necrosis were subsequently confirmed intraoperatively. Furthermore, the surgical team deferred emergent aortic repair because of concern for severe, potentially uncontrollable hemorrhage associated with the recent cesarean delivery and the anticipated need for cardiopulmonary bypass with hypothermic circulatory arrest, which the surgical team considered to pose a substantial risk of perioperative mortality.

Overall, short‐term in‐hospital mortality among patients with mesenteric malperfusion has been reported at approximately 39%, compared with approximately 7.2% among patients without malperfusion [6]. The presence of mesenteric malperfusion therefore represents an important determinant of outcome in acute Type A aortic dissection. Although immediate open aortic repair remains the standard treatment, restoring central aortic flow does not necessarily result in immediate resolution of visceral ischemia, particularly when static branch‐vessel obstruction is present. Furthermore, reperfusion of ischemic bowel during cardiopulmonary bypass may contribute to systemic ischemia–reperfusion injury. These considerations have led some to consider an endovascular reperfusion‐first strategy in carefully selected patients with mesenteric malperfusion.

The specific endovascular intervention should be determined by the mechanism of malperfusion. In selected patients, TEVAR may address downstream aortic pathology by covering an appropriate entry tear and promoting true‐lumen expansion, potentially improving visceral perfusion when malperfusion is predominantly dynamic. In contrast, endovascular fenestration creates a communication between the true and false lumens to equalize pressure, whereas visceral artery stenting can directly relieve static obstruction of vessels such as the superior mesenteric artery. In selected patients with anatomically defined malperfusion, these approaches may restore mesenteric perfusion before definitive open aortic repair while avoiding immediate cardiopulmonary bypass and hypothermic circulatory arrest [2, 6, 8, 9]. However, the available evidence is largely observational and derived from nonpregnant populations, and there are no established pregnancy‐specific recommendations regarding the use or sequencing of these interventions.

In the present case, mesenteric malperfusion was clinically suspected but could not be anatomically confirmed before surgery because dedicated abdominal vascular imaging was not obtained. Progressive metabolic acidosis and renal dysfunction raised concern for evolving visceral ischemia, and extensive bowel ischemia and necrosis were subsequently identified during operative exploration. Because the mechanism and anatomic extent of visceral malperfusion were never established radiographically, it is not possible to determine whether an endovascular intervention would have been technically feasible, whether reperfusion would have been achieved, or whether earlier intervention would have altered the outcome.

This case also highlights the importance of maintaining a high index of suspicion for acute aortic syndrome in pregnant patients presenting with chest or back pain. In particular, marked aortic root dilatation identified on PE‐protocol CT should prompt urgent evaluation of the entire aorta, even when the initial study was obtained for an alternative diagnosis. Furthermore, progressive metabolic acidosis, renal dysfunction, or otherwise unexplained clinical deterioration in a patient with acute Type A aortic dissection should raise concern for visceral malperfusion, even in the absence of overt hemodynamic instability or absent peripheral pulses.

Given the rarity of acute Type A aortic dissection complicated by suspected visceral malperfusion during pregnancy, management requires individualized multidisciplinary decision‐making involving cardiothoracic surgery, vascular or endovascular specialists when available, obstetrics, anesthesiology, and critical care. Although reperfusion‐first strategies have been described in selected nonpregnant patients with anatomically defined malperfusion, the evidence remains predominantly observational, and there are no established pregnancy‐specific recommendations regarding the optimal sequence of visceral reperfusion, cesarean delivery, and definitive aortic repair. This case therefore underscores both the importance of early recognition of visceral ischemia and the substantial uncertainty that remains regarding optimal management in this rare clinical scenario.

Author Contributions

Tam Le: conceptualization, investigation, methodology, resources, writing – original draft, writing – review and editing. Steven Chok: investigation, resources, writing – original draft, writing – review and editing. Khuram Khan: supervision, writing – review and editing.

Funding

The authors have nothing to report.

Consent

Written informed consent was obtained from the patient family for publication of this case report and any accompanying images.

Conflicts of Interest

The authors declare no conflicts of interest.

Data Availability Statement

Data sharing not applicable to this article as no datasets were generated or analysed during the current study.