AUTHORS' CHRONICLES

Aortic arch calcification is a bad sign in acute coronary sindrome

La calcificación del arco aórtico es un mal signo en el síndrome coronario agudo

Tsu-Lin Yang¹

1 Taipei Veterans General Hospital, Taipei, Taiwan

Tsu-Lin Yang describes for SIIC his article published in Acta Cardiologica Sinica 33(3):241-249, May 2017.

Taipei, Taiwán (special for SIIC)

Aortic calcification, easily detected by chest X-ray examination, was first advocated for risk stratification of cardiac events among middle-aged patient populations in the 1990s. Subsequent study had reported that thoracic aortic calcification was also linked to with a higher incidence of coronary heart disease. The relationship between aortic calcification and hard outcomes suggests that chest X-ray examination may be a good candidate for risk stratification for ACS patients due to its widespread availability, ready feasibility and easy interpretability. Furthermore, calcification in aortic arch is more reliably detected than aorta in thoracic or abdominal portion in chest X-ray examination, which were often obscured by other intra-thoracic and intra-abdominal organs. The connection between AAC and clinical outcomes in ACS patients was incompletely investigated. Our study aimed to examine the epidemiology, coronary characteristics as well as clinical outcomes of ACS patients with AAC and clarify whether AAC play a prognostic role in ACS patients.

Patients admitted to coronary care unit of a tertiary referral medical center under impression of acute coronary syndrome were retrospectively investigated. The degree of calcification of the aortic arch was divided into 4 levels from AAC grade 0 to grade 3, defined as follows: grade 0, no visible calcification; grade 1, small spots of calcification or a single thin area of calcification; grade 2, one or more areas of thick calcification; grade 3, circular calcification of the aortic knob. The primary endpoint was composite of long term major adverse cardiovascular events. The secondary endpoints were 30-day and long-term all-cause mortality.

From January 1 to December 31, 2013, totally 225 patients with acute coronary syndrome (mean age 72 ± 26 years, 75% male) were enrolled, 143 of whom had detectable aortic arch calcification. Those who had calcified aortic arch were older, had higher Killip classification and Thrombolysis In Myocardial Infarction score with lower probability of single vessel disease. Acute coronary syndrome patients with aortic arch calcification had significantly higher 30-day mortality (17.3% vs. 7.1%, log-rank p = 0.021). During a mean follow-up of 165 ± 140 days (maximal 492 days), the calcification group had significantly increased cardiovascular deaths (27.6% vs. 11.2%, log-rank p = 0.002), all-cause mortality (28.3% vs. 11.2%, log-rank p = 0.001) and composite endpoint of major adverse cardiovascular events (39.4% vs. 24.6%, log rank p = 0.011). The all-cause mortality rate during follow-up escalated grossly with the AAC grade, though the survival differences did not reach statistical significance between grade 0 and 1, and between grade 2 and 3. Thirty-six (28.3%) mortalities occurred among AAC(+) group and 11 (11.2%) among AAC(-) group. Among AAC(+) mortalities, 35 (97.2%) were cardiovascular death, including fatal MI, heart failure and sudden cardiac death. The only one non-CV death (2.8%) was cancer-related, which occurred at the 27th day of index ACS episode. All 11 AAC(-) mortalities were cardiovascular death. The major adverse cardiovascular event rate significantly escalated with AAC grade (p for trend < 0.001). After adjusting age, gender, diabetes mellitus and hypertension, aortic arch calcification was an independent risk factor for primary and secondary endpoints among patients with acute coronary syndrome. This article is the first study to elucidate the relationship between AAC and cardiovascular outcomes in patients with ACS, and that the major adverse cardiovascular event rate escalates with each calcification grade point increased. The survival difference between grade 0 and grade 1, and between grade 2 and grade 3, had not reached statistical significance. Possible explanation would be that tiny calcified spot in aortic arch on chest X-ray may hint a certain but small degree of derangement on cardiovascular system, but may not be sufficient for translating into survival difference. Recent study demonstrated that AAC represented generalized vascular stiffness and enhanced brachial-ankle pulse wave velocity. Our study is the first to show that AAC has a strong prognostic correlation in ACS patients. AAC is easily and readily detectable by routine chest X-ray examination, providing practical prognostic information on clinical outcomes when applied to patients with ACS, and it is reasonable to pay more attention to these extremely high-risk ACS patients. Further studies for different treatment strategies tailored for optimal risk reduction would be needed in ACS patients with aortic arch calcification.

In conclusion, aortic arch calcification from chest X-ray examination in patients with ACS provides valuable prognostic information on clinical outcomes. Studies with larger patient numbers would be needed to confirm this observation and delineate the detail picture of clinical outcomes in 4 AAC grade groups. Different principles of management for ACS patients with aortic arch calcification might also be needed and tested in subsequent studies.