[Meta-analysis of the prognosis of thoracic aortic dissection: changing mortality in the last four decades].

The acute dissection of the thoracic aorta is a potentially lethal event with a death rate of 1 to 2% per hour urging for undelayed diagnosis and adequate treatment. First, this paper highlights both the demographic characteristics and the classification according to anatomical and prognostic criteria, i.e. class I to III according to DeBakey and type A and B according to Daily (or Stanford). Moreover, the etiology of aortic dissection is explained, including factors such as degenerative changes of the aortic media layer, chronic trauma from hypertension, primary connective tissue disease and acute deceleration trauma. Second, the clinical criteria of acute (within 14 days of the index event) and chronic dissection (> 14 days) is discussed with respect to the current literature. The dominant part of this paper represents a meta-analytic approach comprising all available literature sources with respect to emerging changes in the prognosis of thoracic aortic dissection over 40 years as a function of either the type, the anatomic location, the acuity or the impact of medical or surgical treatment of this disorder. The meta-analysis revealed that in acute and chronic type A dissection medical treatment alone failed to lead to a significant improvement of 30 day-mortality rate (Tables 1 and 2, Figure 1). However, with surgical interventions the 30 day-mortality rate was continuously lowered from 60% to 10% within the past 30 years. A similar evolution was observed for the chronic type A dissection (Tables 3 and 4, Figure 2). Furthermore, the meta-analysis revealed that the acute type B dissection benefits from medical treatment, especially antihypertensive medication since the 30 day-mortality of 40% in 1960 decreased to less than 10% at present with monitoring and effective medication (Tables 1 and 2, Figure 3). In case of chronic type B dissection the literature survey revealed mortality numbers fluctuating between 2% and 20% without a clearcut beneficial effect of medical therapy throughout these years, though possibly revealing some advantage over surgical treatment. Thus, both for the acute and chronic type B dissection the antihypertensive therapy is considered treatment of first choice, whereas surgical interventions may be necessary for complicated and progressive cases. In summary, compared to the natural course of thoracic aortic dissection with only 10% survival-rate after one year of onset (Table 9, Figure 5), any effective mode of treatment may significantly lower the high spontaneous death rate.(ABSTRACT TRUNCATED AT 400 WORDS)