[Aortic diseases : Modern diagnostic and therapeutic strategies]

Predictive factors for type A aortic dissection mortality based on electrocardiogram parameters and clinical presentations

BACKGROUND

Aortic dissection is a rare but potentially lethal disorder and may be associated with electrocardiogram (ECG) changes. In this study, we aim to investigate ECG-related parameters alongside clinical presentations of type A aortic dissection to come up with the predictive factors for the severity of the disease and its mortality rate.

METHODS

In this retrospective study, 201 patients with type A aortic dissection were studied between March 2015 and March 2020. Two expert cardiologists blinded to the diagnosis studied former and new patients' ECGs and recorded changes.

RESULTS

Two-hundred and one patients, including 143 (71.1%) men and 58 (28.9%) women, presented with acute dissection of the aorta, were studied. Forty-four (21.8%) and 84 (41.7%) patients had ST-segment elevation and depression in ECG, respectively. Bivariate analysis revealed that higher heart rate (p = 0.006), longer QTc (p = 0.044), and ST-segment elevation in aVR lead (p = 0.044) were associated with mortality in the patients. Multivariate regression showed higher heart rate (OR = 1.022, CI = 1.003-1.041, p = 0.012) and ST-segment elevation in aVR (OR = 4.854, CI = 2.255-10.477, p < 0.001) were independently associated with increased odds of mortality in aortic dissection patients. ROC curve analysis showed heart rate equal to or >60 per minute (AUC = 0.625, sensitivity = 86%, specificity = 10%, p = 0.019) and ST-segment elevation in aVR >0.5 mm (AUC = 0.854, sensitivity = 75%, specificity = 92%, p < 0.001) were associated with a higher mortality rate.

CONCLUSION

Heart rate equal or >60 and ST-segment elevation >0.5 mm in aVR lead can be used as predictive factors for mortality of patients with type A aortic dissection.

The Silent Threat: A Case of Iatrogenic Asymptomatic Aortic Dissection Post Coronary Artery Bypass Grafting

Asymptomatic aortic dissection (AD) is a rare but potentially life-threatening complication that can occur following coronary artery bypass graft (CABG) surgery. While CABG is a well-established surgical procedure for managing multivessel coronary artery disease, it can inadvertently predispose patients to the development of AD, especially in those with pre-existing aortic pathology. The pathophysiology underlying AD after CABG is multifactorial, with factors, such as atherosclerosis, manipulation of the aorta during surgery, and hemodynamic stress, playing significant roles. Notably, the absence of symptoms poses a diagnostic challenge, as patients may remain unaware of the underlying condition until a catastrophic event occurs. Therefore, a high index of suspicion and vigilant postoperative monitoring are crucial in identifying asymptomatic AD. Diagnostic modalities including imaging techniques, such as computed tomography angiography (CTA), magnetic resonance imaging (MRI), and echocardiography, play pivotal roles in confirming the diagnosis and determining the extent of the dissection. Prompt surgical intervention is generally recommended in symptomatic patients or those with evidence of impending complications. We hereby present a case report of a patient who presented with asymptomatic AD post CABG surgery and discuss the pathophysiology, presentation, diagnostic workup, and treatment options.

Computational Fluid Dynamic Technique for Assessment of How Changing Character of Blood Flow and Different Value of Hct Influence Blood Hemodynamic in Dissected Aorta

Using computer tomography angiography (CTA) and computational structural analysis, we present a non-invasive method of mass flow rate/velocity and wall stress analysis in type B aortic dissection. Three-dimensional (3D) computer models of the aorta were calculated using pre-operative (baseline) and post-operative CT data from 12 male patients (aged from 51 to 64 years) who were treated for acute type B dissection. A computational fluid dynamics (CFD) technique was used to quantify the displacement forces acting on the aortic wall in the areas of endografts placement. The mass flow rate and wall stress were measured and quantified using the CFD technique. The CFD model indicated the places with a lower value of blood velocity and shear rate, which corelated with higher blood viscosity and a probability of thrombus appearance. Moreover, with the increase in Hct, blood viscosity also increased, while the intensity of blood flow provoked changing viscosity values in these areas. Furthermore, the velocity gradient near the tear surface caused high wall WSS; this could lead to a decreased resistance in the aorta’s wall with further implications to a patient.