Elsevier

International Journal of Cardiology

Volume 241, 15 August 2017, Pages 326-329
International Journal of Cardiology

Insight into the incidence of acute aortic dissection in the German region of Berlin and Brandenburg

https://doi.org/10.1016/j.ijcard.2017.05.024Get rights and content

Abstract

Background

Stanford acute type A aortic dissection (ATAAD) is a potentially lethal condition. Epidemiology studies show a statistical incidence in Europe of approximately 2–16 cases/100,000 inhabitants/year. In Germany, the estimated incidence (here subsumed under “thoracic aortic dissection” with 4.63 cases/100,000 inhabitants/year) is mainly extracted from medical death certificates by the German Federal Statistical Office. The prehospital incidence of ATAAD deaths is largely unknown. Since patients often die in the pre-hospital setting, the incidence of ATAAD is therefore likely to be higher than current estimates.

Material and methods

For the period from 2010 to 2014, we retrospectively analyzed all in-hospital ATAAD data from two of the largest cardiac surgical centers that treat ATAAD in the Berlin-Brandenburg region. In addition, autopsy reports of all forensic medicine institutes and of one large pathological provider in the region were analyzed to identify additional non-hospitalized ATAAD patients. Based on these findings, the regional incidence of ATAAD was calculated.

Results

In addition to in-hospital ATAAD patients (n = 405), we identified additional 145 lethal ATAAD cases among 14,201 autopsy reports. The total of 550 ATAAD cases led to an estimated incidence of 11.9 cases/100,000 inhabitants/year for the whole Berlin-Brandenburg region. Arterial hypertension, pre-existing aortic dilatation, and hereditary connective tissue disorder were found in, respectively, 62.7%, 10%, and 1.8% of patients.

Conclusion

ATAAD is more frequent than previously reported. Our results show that when patients who die outside of cardiac surgery centers are included, the incidence of ATAAD significantly exceeds the rate reported by the Federal Statistical Office.

Introduction

Acute aortic dissection is defined as a split between the vascular intima and media caused by a lesion in the intima. If this lesion (“entry”) is located in the ascending aorta proximal to the branch of the left subclavian artery, it is defined in the Stanford classification as an acute type A aortic dissection (ATAAD). ATAAD is a life-threatening event and survival without surgical treatment is dismal [1], [2]. The mortality rate is 50% after 48 h and 75% after 2 weeks; in the early period mortality is 1–2% per hour [3], [4], [5]. The most common complication is rupture of the thoracic aorta, which is responsible for 80% of deaths (Fig. 1) [5]. After diagnosis, emergency operation (surgical replacement or repair of the aortic root, ascending aorta and aortic arch) is warranted.

The reported incidence of ATAAD varies greatly in the international literature and, depending on the underlying database, ranges from 2 to 16 cases/100,000 inhabitants/year [9], [10], [11], [12]. For the Federal Republic of Germany the official death statistics for 2014 show an incidence of “thoracic aortic dissection” of 4.63 per 100,000 population per year [13]. This statistic probably underestimates the number of cases outside of clinical settings and ATAAD is not recorded separately but is subsumed under “thoracic aortic dissection” (which includes Stanford type B cases). The underestimation of out of hospital ATAAD's combined with the high pre-clinical mortality of the disease render this analysis unreliable. The pre-clinical situation is not only relevant from the epidemiological aspect but also has important clinical implications [14], [15], [16]. The neglection of non-hospital mortality and the current focus on the clinical incidence of ATAAD suggests that the true incidence of ATAAD is likely to be higher than assumed. A more realistic assessment of the incidence of ATAAD must therefore include both, the data of patients who were hospitalized due to an ATAAD and data on ATAAD deaths that occurred outside the clinical setting. However, cause of death by aortic dissection or more specifically death by ATAAD is frequently not recognized by the doctors filling in the death certificates. The manner of death is, therefore, often recorded as, e.g. sudden cardiac death or as “uncertain”. The latter cases may lead to a forensic autopsy if this is ordered by the public prosecutor/the court — which of course does not apply to every uncertain death. Furthermore, differentiation between Stanford type A and Stanford type B dissection is not possible by exterior postmortem examination only.

It is commonly known that postmortem external examinations are inaccurate with regard to the exact cause of death, especially when these postmortem external examinations are performed by inexperienced physicians [17].

Low forensic autopsy rates (e.g. about 7% of all deaths in Berlin; see Table 1) distort the distribution of disease frequencies among the deceased from a particular region, as was shown in the “Görlitzer study” in 1986/87 (almost 100% autopsy rate) with marked disagreement between cause of death given in the death certificates and autopsy findings [17].

Therefore, the analysis of autopsy reports can constitute a suitable method for generating epidemiological data primarily for the pre-clinical stage, when the manner of death was certified as “uncertain” or “non-natural” and a forensic autopsy was ordered by the public prosecutor/the court [14], [15], [16]. Autopsy is known to be the gold standard of (emergency) medical quality checks in the case of death.

This study aimed to identify the incidence of ATAAD among all deaths undergoing either forensic or clinical autopsy in our region. From these data the rate of ATAAD among pre-clinical deaths was estimated and combined with known clinical cases to achieve an estimate of total population based ATAAD incidence.

Section snippets

Material and methods

The Berlin-Brandenburg region has 6 million inhabitants in a temperate zone in the north-east of the Federal Republic of Germany, where the average age is 42.9 years for Berlin (as of 2014) [18] and 45.7 years for Brandenburg (as of 2010) [19]. For further demographically relevant parameters, we accessed regional data from the Federal Statistical Office (www.destatis.de).

ATTAD was diagnosed in clinical cases and autopsy reports according to the Stanford classification, i.e. entry of dissection is

Results

For the observation period, in addition to the clinical ATAAD patients (n = 405), we identified 145 further fatal ATAAD cases in autopsies, resulting in a total of 550 cases; of these 345 (64.5%) were men and 195 (35.5%) were women. This distribution was similar in all institutions with the exception of the pathological study group (Berlin-Neukölln Vivantes), where men comprised 33.3%.

The average age was 61.4 ± 14.2 years, the youngest patient being 20 years and the oldest patient 100 years old. The

Discussion

The main result of the present investigation is that the estimated incidence of ATAAD of 11.9/100,000/year is considerably higher than the number of 4.6 of the German Federal Statistical Office which also includes Stanford type B dissections. The reasons for this discrepancy may be due to several reasons, some of which have already been mentioned in the Introduction. In cases of out of hospital deaths, ATAAD may be misdiagnosed as sudden cardiac death or death due to myocardial infarction by

Conflict of interest

The authors report no relationships that could be construed as a conflict of interest.

Acknowledgement

We thank Monia Gieb and Anne Gale for translating the manuscript from German.

References (21)

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    Studies including prehospital deaths have estimated prehospital mortality to range from 18% to 38%.3,17-19 Two separate studies over a similar time period in Germany estimated the incidence of aortic dissection to be 2.7 per 100,000 person-years when accounting for only those who underwent intervention,20 and as high as 11.9 per 100,000 with the inclusion of autopsy reports in the same population.18 Our study includes patients with the diagnosis of aortic dissection as the underlying cause of death and found a stable rate of combined TAAD and TBAD at around 3.4 per 100,000.

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