Imaging in Peripheral Arterial Disease by Unknown

Author:Unknown
Language: eng
Format: epub
ISBN: 9783030245962
Publisher: Springer International Publishing

Peripheral artery disease

Coronary heart disease

Pathophysiology

Atherothromboembolic

Atherothrombotic

Presentation

Chronic and progressive

Acute

Total occlusions

More prevalent

Less prevalent

Gender

Equal in both males and females

Slight male predominance (55%)

Risk factors

Age, smoking, and diabetes mellitus

Hypertension, lipid disorders

CLI Versus IC

The natural history of untreated critical limb ischemia is largely unknown because in current era of endovascular therapies, almost all patients undergo medical treatment to prolong survival and intervention to attempt limb salvage. A systematic review of studies from 1990 to 2015 found that when followed clinically, the 5-year cumulative incidence of patients with claudication that progressed to CLI is 21% [29]. Patients with CLI who do not undergo revascularization have a 20% mortality rate and a 50% risk of major amputation in 1 year. The majority of patients with IC do not develop CLI; rather CLI may be distinct manifestation of PAD. Various studies have found some key pathophysiological differences between CLI and IC.

A recent study by Ryan and colleagues [30] analyzed gastrocnemius muscle biopsy samples from age-, gender-, and risk factor-matched cohort of 32 healthy adults, 27 patients with IC, and 19 patients with CLI using transcriptome (mRNA) sequencing. It was found that the gene expression profile was strikingly different in CLI tissues or stated differently the patients with PAD but IC were more similar to controls than to PAD but CLI. Mitochondrial respiratory capacity was lower in CLI muscle myofibers despite similar mitochondrial content (number)/density between IC and CLI patients . Mitochondriopathy including reduced mitochondrial oxidative capacity, reduced electron transport system enzyme function, and decreased abundance of mitochondria-associated mRNAs and proteins in patients with CLI may be a target for focused adjuvant therapeutics.

When looking at imaging needs for development of novel therapeutics, it is important to pay attention as to whether differences between CLI and IC patients were examined. MR spectroscopy data which showed dissociation of mitochondrial function and muscle perfusion on patients with IC as will be discussed cannot be generalized to CLI population. Integrated imaging techniques that measure in parallel some of these processes that have been discussed in this chapter will be useful in further evaluation of novel therapies in the clinical trials.

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