Peripheral arterial calcification: prevalence, mechanism, detection, and clinical implications

Abstract

Vascular calcification (VC), particularly medial (Mönckeberg's medial sclerosis) arterial calcification, is common in patients with diabetes mellitus and chronic kidney disease and is associated with increased cardiovascular morbidity and mortality. Although, the underlying pathophysiological mechanisms and genetic pathways of VC are not fully known, hypocalcemia, hyperphosphatemia, and the suppression of parathyroid hormone activity are central to the development of vessel mineralization and, consequently, bone demineralization. In addition to preventive measures, such as the modification of atherosclerotic cardiovascular risk factors, current treatment strategies include the use of calcium-free phosphate binders, vitamin D analogs, and calcium mimetics that have shown promising results, albeit in small patient cohorts. The impact of intimal and medial VC on the safety and effectiveness of endovascular devices to treat symptomatic peripheral arterial disease (PAD) remains poorly defined. The absence of a generally accepted, validated vascular calcium grading scale hampers clinical progress in assessing the safety and utility of various endovascular devices (e.g., atherectomy) in treating calcified vessels. Accordingly, we propose the peripheral arterial calcium scoring system (PACSS) and a method for its clinical validation. A better understanding of the pathogenesis of vascular calcification and the development of optimal medical and endovascular treatment strategies are crucial as the population ages and presents with more chronic comorbidities.

Keywords: atherosclerosis; peripheral artery disease; vascular calcification.

Figure 1

Schematic diagram depicting multiple mechanisms leading to vascular calcification.

Figure 2

The fluoroscopic (panel A) and digital subtraction angiographic (panel B) appearance of severe calcification involving the SFA.

Figure 3

The fluoroscopic (panel A), Duplex ultrasonographic (panel B) and surgical appearance (panels C,D) of severe vascular calcification in a 64 year old diabetic female with symptomatic peripheral arterial disease. Severe circumferential calcification involves the common femoral artery (panel A, black arrows). Sonographic “drop-out,” seen as voids in the sonographic signal, is caused by dense calcification (panel B, white arrows). Common femoral artery incised during endarterectomy demonstrating densely calcified segment (black arrows, panel C) and after excision (panel D).