**1. Introduction**

228 Front Lines of Thoracic Surgery

[59] Leshnower BG, Thourani VH, Myung RJ, et al. Aortic Arch Reconstruction at 28°C: A

*Thorac Surg* Submitted.

Comparative Analysis of Outcomes using Mild vs Moderate Hypothermia. *Ann* 

Type A acute aortic dissection is one of the most serious cardiovascular conditions and is associated with significant morbidity and mortality. A half century ago, Hirst et al published a milestone article describing the linearized mortality rate of one percent per hour after the onset of an ascending aortic dissection [1]. Hence, the importance of accurate, quick and reliable diagnosis, as the timing of procedure is vital for optimal management of this highly lethal condition. Despite improvements in the diagnostic modalities, surgical techniques and perioperative care, the overall mortality remains high, between 10% and 30% [2].

Due to its major role in systemic perfusion, the aorta and its main branches after dissection are often challenging when trying to prevent surgical morbidity and mortality. The complexity of aortic dissection presents not only a pure cardiovascular surgical task, but also consideration must be given to protection of the myocardium, cerebrum, peripheral tissues and organs. An early fatal result of aortic dissection is due to ischaemic injury to the brain or heart, although longer peripheral ischaemia can cause multiorgan failure resulting in extended hospital stay, increased morbidity and mortality. Alexis Carrel highlighted the risks of surgery in 1910 with the following short summary on aortic interventions: "The main danger of the aortic operation does not come from the heart or from the aorta itself, but from the central nervous system." Even a century later, we are still trying to optimize cerebral protection, despite having significantly wider range of diagnostic and therapeutic modalities.

Advances in our understanding of varying pathologies of aortic dissections have improved as have the technological developments in the modes of detection. These advances together with improved therapeutic options have raised expectations for better outcomes.

Maik Foltan1, Peter Ugocsai2, Andrea Thrum1, Alois Philipp1, Steven A. Livesey3, Geoffrey M. Tsang3 and Sunil K. Ohri3

Recent Advances in the Management of Acute Aortic Syndrome 231

findings of these lesions generally demonstrate significant intimal atherosclerosis, which is not a constant finding in aortic dissection biopsies. Studies suggest that aortic dissection is an end process with a wide pathological spectrum, many of which facilitate weakening and/or increased stress of the aortic wall. The chain of pathological events might begin with a small superficial intimal rupture; atherosclerotic ulcers may provide a good millieu for development of such a tear. Alternatively, disruption of vasa vasorum might result in an intramural haematoma, which later ruptures into the aortic lumen or leads to dissection. However, it is likely that many aortic dissections develop without having a pre-stage of

Although the typical symptom is described as sharp, tearing, ripping chest pain, the presentation is diverse and about 10% do not complain of pain; sometimes the aortic pathology is an accidental clinical finding. In some patients shoulder or back pain occurs or just a husky voice, with or without shortness of breath and/or haemophthysis. Hypotension or shock is seen in 25% of patients, whereas hypertension can also be a presenting symptom, although more often found in type B dissections. Further findings, such as migrating pain, neurological deficits, acute abdomen, cardiac failure, myocardial ischaemia, aortic valve regurgitation are less common. Connective tissue diseases are characterized by additional specific symptoms, i.e. skeletal, pharyngeal or lens

Early acute diagnosis can be vital, as an emergency surgery may be indicated. Blood pressure control is essential, and a goal of systolic ≤110 mmHg is recommended. The administration of β-blockers, sodium-nitroprusside, calcium-channel-blockers with analgesia is helpful, if indicated. In some advanced dissections resustitative measurements

haematoma - ++ ++ +++ Penetrating ulcer - + +++ +++

Dissection entry + +++ ++ ++

regurgitation +++ +++ - +++

Periaortic bleeding - + +++ +++

Transoesophageal echocardiography

+ +++ +++ +++

+++ +++ ++ ++

Computed tomography

Magnetic resonance imaging

intramural haematoma or penetrating ulcer [8].

**2.3 Presentation and diagnosis** 

abnormalities and extreme laxity [3].

Aortic dissection

Pericardial effusion

Intramural

Aortic

such as intubation and pericardiocentesis may be required.

Table 1. Efficacy of different imaging modalities in AAS.

Transthoracic echocardiography
