The coincidence of type A aortic aneurysm and dissection secondary to bicuspid aortic valve (BAV) in adults with untreated coarctation of the aorta (CoA) is a rare finding because there are almost no “abnormalities” in these patients’ medical histories. Most patients die of aortic rupture before surgery. This case report involves a patient who was successfully treated using composite surgical procedures with perioperative veno-arterial extracorporeal membrane oxygenation (VA-ECMO) support.
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A 47-year-old man was admitted to the emergency department with a history of unexplained weakness and sweating for 4 hours, which then progressed to unconsciousness for 2 hours. Physical examination indicated that blood pressure was 100/84 mmHg and breathing worsened (26 times per minute), but the patient's pupils were still sensitive to light. A blood gas analysis indicated that the partial pressure of oxygen was only 28 mmHg. Electrocardiogram examination indicated acute inferior myocardial infarction. The patient was diagnosed with acute cardiogenic shock. Therefore, on admission to the emergency intensive care unit (ICU), VA-ECMO, with blood drainage from the right femoral venous access and reinfusion through the right femoral arterial cannula, was used as a salvage therapy to assist the heart by ensuring part or all of the systemic blood flow. Bedside color Doppler echocardiography revealed the pathologic characteristics of BAV, ascending aortic aneurysm (maximum diameter, 7.2 cm), and dissection. Computed tomography angiography (CTA) showed huge ascending aortic aneurysms with dissection (maximum diameter, 9 cm) [Figure 1A], combined with CoA (minimum diameter, 7 mm) [Figure 1B].
Emergency aortic root and ascending aortic replacement (involving a composite mechanical valve conduit with a 21-mm mechanical valve prosthesis and a 28-mm direct vascular prosthesis) was performed through a median sternotomy with double arterial perfusion (right axillary artery and femoral artery). Concomitant ascending-descending aortic shunt distal to the site of CoA transposition was completed, in addition to coronary artery bypass grafting with a saphenous vein graft to the right coronary artery. The cardiopulmonary bypass and cross-clamp durations were 273 and 184 minutes, respectively. The mechanical ventilation duration was 96 hours, and the VA-ECMO support duration was 117 hours. Postoperative CTA showed that the bypass conduit provided optimal blood supply from the ascending aorta to the descending aorta [Figure 2]. The patient recovered uneventfully and was discharged from hospital.
This case report involves an adult with acute cardiogenic shock resulting from ascending aortic aneurysm and dissection secondary to BAV and CoA. Ascending aortic aneurysm and acute type A aortic dissection is relatively frequently reported. However, there have only been sporadic reports on ascending aortic aneurysm and dissection secondary to BAV and CoA.[2,3] One case was a pregnant woman who accepted emergency caesarean section and aortic surgery but she was learn of the CoA and had been repaired in the neonate period. In addition, Turner's syndrome is the most common chromosomal abnormality in females, which is also reported with aortopathy. Successful treatment involving surgical repair with preoparative VA-ECMO support, as in this case, has, to our knowledge, rarely been reported in the literature.
BAV is usually associated with aortic aneurysm formation and aortic dissection due to the associated blood flow pattern and fluid dynamics. CoA can be asymptomatic in the early years, like BAV, but careful physical examination, including pulse palpation and blood pressure assessment at the 4 extremities, may expediate the diagnosis. BAV and/or CoA are often associated with medial degeneration and dilatation of the ascending aorta. The anatomic dysfunction of BAV helps to limit the degree of physiologic obstruction around the CoA and reduce the clinical manifestations (such as hypertension proximal to the lesion), but potentially at the expense of cardiac hypertrophy and aortic dilation. The dissection of an ascending aortic aneurysm is rare but has a high mortality rate due to the risks of aortic rupture, myocardial infarction, and aortic regurgitation.
This case report demonstrates that physicians need to be alert for cardiogenic shock resulting from cardiac infarction and vigilant against missing a diagnosis of aortic dissection. Echocardiography should be used to detect potential anatomic diseases rather than coronary artery disease. VA-ECMO should be considered as a salvage therapy to maintain life and to bridge etiological treatment when the patient experienced acute cardiorespiratory failure. A CTA scan must follow after the diagnosis of the ascending aorta and/or the aortic arch dissection by echocardiography to avoid misdiagnosis of CoA. The emergency doctor comprehensively evaluated the patient. The doctor then initiated VA-ECMO with multidisciplinary support, after the relative's agreement regarding this procedure. The treatment plan was based on the acute cardiac infarction due to aortic dissection, the decompensated respiratory failure with no signs of brain injury, the availability of the resources to conduct the emergency procedure, and the patient's young age and seemingly good physical fitness. The left radial artery was catheterized to continuously monitor the mean arterial pressure (MAP) so that it could then be controlled according to cardiac function and organ perfusion. Given the patient's health condition, involving ascending aortic dissection and normal peripheral organ function, maintaining MAP at about 60–80 mmHg during ECMO was appropriate. It is also recommended to monitor oxygen saturation through the left hand and conduct arterial blood gas analysis through the right hand, in order to detect any discrepancy in blood perfusion between the upper and lower body. Although it is suggested that the heart rate should be controlled at around 60 beats per minute, the patient did not undergo standard strict depression with a ß-blocker, due to the risk of cardiac arrest resulting from right coronary artery ischemia.
Additionally, ECMO should not be prematurely withdrawn postoperatively if the right ventricular function is still poor, even if, as in the current case, the patient resumes spontaneous breathing. During the whole follow-up period, the patient's right ventricular function was still not restored to normal even though the blood supply was restored after bypass grafting to the right coronary artery. The patient's tricuspid annular displacement (based on echocardiography) was greatly improved but not fully recovered at the outpatient follow-up point in the third month. Therefore, ECMO is strongly recommended to ensure continuous support in the ICU in order to improve right ventricular recovery in the early postoperative period. Bedside echocardiography examination was conducted daily. Drugs to improve right ventricular function such as digoxin and diuretic were also prescribed.
In conclusion, this case involved a patient in a critical condition with ascending aortic aneurysm and dissection secondary to complex congenital heart defects, who was successfully treated with composite surgical procedures combined with life-saving VA-ECMO.
This work was supported by the National Natural Science and Technology Foundation of China (81800274 to QJ), Sichuan Science and Technology Program (2021JDJQ0041 to QJ), and Grant for Clinical Translation Research of Sichuan Provincial People's Hospital (2017LY07 to QJ).
Xiaobo Huang, and Keli Huang participated in the design of therapeutic regimen and data collection. Qin Jiang, Juan Du, Tao Yu and Mingliang Zuo participated in the writing of the manuscript and data analysis. All authors read and approved the final manuscript.
Conflicts of Interest
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