Case Report

Painless Type B aortic dissection presenting as acute congestive heart failure

Abstract

Aortic dissection (AD) is often a life-threatening condition that may not always present with Classic symptoms, such as abrupt chest pain that sometimes radiates to the back, abdominal pain, or back pain alone. An atypical presentation makes it difficult to diagnose promptly. Painless AD occurs in approximately 5% to 15% of patients, and the diagnosis may often be delayed. We report a case of painless AD where the patient presented with acute congestive heart failure. On physical examination, he had a very high blood pressure in both his left and right arms, which was difficult to control. However, the pulse was poor and equal in both legs. The diagnosis of AD was reached via a combination of radiography, computed tomography with Contrast enhancement, and a high index of clinical suspicion. The patient underwent surgery and ultimately experienced a successful outcome.

Aortic dissection (AD) is a medical emergency. Without prompt recognition and treatment, its mortality rate is high. Classic acute AD has been described as presenting with sudden, severe chest, back, or abdominal pain character- ized as ripping or tearing in nature [1]. An atypical presentation makes it difficult to diagnose promptly, especially if the patient is experiencing no characteristic pain. Painless dissection occurs in 5% to 15% of patients with AD [2].

Although recent literature has reported on patients with painless AD, there have been less reports that have described cases presenting with acute congestive heart failure. This article reported on a case with painless AD presenting with acute congestive heart failure.

A 65-year-old man was admitted to the emergency department (ED) complaining of dyspnea. He was unable to lie down and he experienced sweating. These symptoms

appeared after climbing 4 flights of stairs. His medical history included hypertension for nearly 40 years controlled with calcium channel blockers. A month before presenting at the ED, he experienced a similar attack, and his blood pressure had remained very high. He did not report experiencing any pain in his head, chest, neck, back, or abdomen. On arrival in the ED, he was fully oriented and cooperative. His blood pressure was 273/140 mm Hg in the left arm and 265/135 mm Hg in the right arm. His heart rhythm was regular, with a rate of 125 beats/min. Respiration rate was 32 breaths/min, and oxygen saturation was 88% by pulse oximetry without oxygen supply. Treatment resulted his blood pressure being reduced, but it still ranged from 160/80 to 190/100 mm Hg. Electrolyte levels, renal function tests, cardiac enzymes, complete blood count, and clotting tests checked in the ED were within normal ranges except for a pro-brain natriuretic peptide concentration of 8624 pg/mL (cutoff b285 pg/mL) and D-dimer concentration of 2.46 mg/L (cutoff b0.5 mg/L). Electrocardiogram demonstrated sinus tachycardia, ST- segment depression in V₄ through V₆. Chest radiograph showed a wide mediastinum, enlarged heart, and bilateral lung congestion (Fig. 1). Further physical examination showed his pulse was strong and equal in both arms, but his pulse was poor and equal in both legs. Suspecting a vascular accident, thoracic computed tomography (CT) with contrast enhancement was conducted. It disclosed a type B AD with an intimal flap in the arch extending into the descending thoracic aorta (Fig. 2). The false lumen of the dissection in the descending thoracic aorta was completely thrombosed, causing severe compression of the true aortic lumen (Fig. 3).

The patient was admitted by cardiovascular surgeons and underwent surgery 2 days later. Postoperation, the pulse becomes strong and equal in both legs.

Aortic dissection has recently gained greater recognition, and it is being diagnosed with increasing frequency using new diagnostic imaging modalities, especially CT in emergency settings. However, as many as 30% of patients ultimately diagnosed with acute dissection are first thought

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Fig. 1 Chest radiograph shows a wide mediastinum, enlarged heart, and bilateral lung congestion.

to be experiencing a different medical condition [3]. The symptoms in patients with AD are more variable than previously recognized.

Fig. 2 An intimal flap in the arch extending into the descending thoracic aorta.

Fig. 3 The false lumen of the dissection in the descending thoracic aorta was completely thrombosed, causing severe compression of the true aortic lumen.

The most common clinical symptom of AD is severe chest or back pain. However, 5% to 15% of patients with AD are pain free on presentation. Compared with patients who have painful AD, patients who have painless AD have higher mortality rate, especially when AD is type B [2]. Other symptoms related to the course of the dissection may complicate the clinical findings of this disease, making Diagnosis difficult. Many cases with AD report various complaints other than pain, especially neurologic and Cardiovascular manifestations. These presentations included upper or lower Extremity weakness or numbness [4,5], hemiparesis [6], heart block [7], Transient global amnesia [8], and others.

D-dimer is the end product of cross-linked fibrin breakdown and indicates active thrombus formation and lysis. Previous studies showed the use of D-dimer measure- ment for the screening of acute AD [9-11]. D-dimer is sensitive for acute AD and potentially represents a useful test for patients who present with a low likelihood of this disease [12]. Our patient denied chest or back pain. He had New York Heart Association class III congestive heart failure accom- panied by an elevated pro-brain natriuretic peptide and D- dimer concentration. Our initial suspicion was that heart failure was only caused by the high blood pressure. However, the blood pressure was very difficult to control. Through examination, we found that the pulse in legs was poor and equal. A CT scan showed a type B dissection with a thrombosed false lumen causing severe compression of the true lumen. This was the reason for the very high blood pressure and the poor pulse in both legs. Therefore, this patient had chronic type B dissection that probably occurred at the first onset of heart failure 1 month earlier. Based on this

Case Report

case, we suggest that painless AD be added to the differential diagnosis for secondary hypertension, especially when it is

References

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difficult to control.

The diagnosis was made by a combination of clinical suspicion and CT scan. Uncontrolled hypertension and the poor pulse in legs may be viewed as clinical clues to the diagnosis.

Acknowledgment

The article was supported by Shanghai Health Bureau Scientific Research Foundation (no. 2007108).

Jia-Fu Liu Qin-Min Ge Miao Chen Lu-Jia Tang Li-Jun Dong Shu-Ming Pan

Emergency Department Xin Hua Hospital

Shanghai Jiaotong University School of Medicine, Shanghai, China

E-mail address: [email protected] doi:10.1016/j.ajem.2009.09.021

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