**7. Complications and prognosis**

Vascular complications of LV-GCA include the formation of arterial stenosis, occlusions and aneurysms [15, 16]. Involvement of the aorta commonly occurs as dilation or aneurysm, as aortic stenosis is unlikely. Stenosis presents as limb claudication, involving more commonly the superior extremities, although the involvement of the inferior extremity is also possible [7, 47]. GCA patients are at an increased risk of developing aortic aneurysms/dissection or large artery stenosis (**Figure 5**). While stenosis mostly occur during the first year, the incidence of aortic aneurysms/dissection increases over the five years following the GCA diagnosis [104].

In the long-term, 10–33% of the patients may develop aortic aneurysms/dissection and around 13% may develop large-artery stenosis [16, 104, 105].

Interestingly, aortic dilation is already present in 15% of the newly diagnosed GCA patients [12] with the thoracic aorta being the most commonly involved [105]. Aortic aneurysms are more frequently found among male patients with identified cardiovascular risk factors that include hypertension, dyslipidaemia and coronary artery disease [16, 17, 106]. It is unlikely that aortic aneurysms result from the persistent inflammatory activity as patients with aortic dilation/aneurysms were found to have lower serum acute-phase reactants and a lower relapse rate [17, 105]. However, increased 18FDG uptake in the aorta on PET performed at the GCA diagnosis was associated with the subsequent development of aortic dilation [107, 108]. It is thus conceivable that a strong inflammatory response at the beginning of the disease followed by remodelling vascular factors and hemodynamic factors (like hypertension), may be more relevant to the development of aortic dilation and aneurysms than a continuous inflammatory process.

Despite all the possible complications, the overall prognosis of GCA is good, with a mortality rate similar to the general population [109]. However, GCA is responsible for a significant morbidity. Around 64% of the patients will have at least on relapse [52] and up to 86% of patients will develop at least on steroid related-complication [110]. Initially it would be thought that LV-GCA patients would not contribute to an increased morbidity as they have fewer ischaemic cranial events that classically have been responsible for the most relevant morbidity associated with GCA [10, 11].

However, LV-GCA patients have a more relapsing disease-course, have higher corticosteroid cumulative doses, and require additional immunosuppressive treatments [7, 95]. Moreover, patients with LV inflammation are at increased risk of developing large-artery stenosis and aortic arch syndrome [54, 105, 106]. In fact, when compared to the general population, survival is decreased in GCA patients with an aortic aneurysm/dissection [104], confirming the negative impact the involvement of large arteries has on both mortality and morbidity associated to GCA.

#### **8. Conclusions**

LV-GCA has been previously misregarded and underdiagnosed. However, there is consistent evidence confirming that large arteries are involved in around twothirds of patients with GCA and one-third of patients with PMR. Classification criteria are inadequate for LV-GCA. A revision of the current criteria is required in the near future. LV-GCA presents a more relapsing-disease course and an increased risk of vascular complications, with LV inflammation being responsible for a considerable increment in the morbidity and mortality associated to this condition. This chapter emphasises the importance of carefully considering the large artery aspects in the management and treatment of patients with GCA.

#### **Acknowledgements**

We kindly thank Dr. Pedro Marques, from the Department of Radiology, Hospital Prof. Doutor Fernando Fonseca, for his collaboration with computed tomography image selection and editing.

We kindly thank Dr. Ângelo Ferreira Silva, from the Department of Nuclear Medicine, Champalimaud Foudation, for his collaboration with 18FDG-PET image selection and editing.

*Extra-Cranial Involvement in Giant Cell Arteritis DOI: http://dx.doi.org/10.5772/intechopen.97715*

Ultrasound images collected by the authors (Serôdio and Trindade) during the assessment of GCA patients with Siemens Acuson X300 equipment, VF13-5 probe, bandwidth 4,4-13,0 MHz.
