Vascular Problems in Diabetes

8/6/2019 Vascular Problems in Diabetes

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Vascular problems in

diabetes



Why does diabetes cause

vascular problems?

• “the pathophysiology of diabetes is clearly linked to

hyperglycemia”

• High glucose damages blood vessels

• No one knows exactly why – some theories

• High glucose levels reduce the levels of nitric oxide inblood vessels

• powerful vasodilator

• Long term – leads to narrowing of blood vessels

• O-GlcNAc

• glucose-derived molecule

• Phosphorylation role in NO release

• O-GlcNAc – competes with phosphorylation



What vascular problems does

diabetes cause?

Microvascular Macrovascular

Retinopathy Ischaemic Heart Disease

Nephropathy Stroke

Neuropathy Peripheral vascular disease



Microvascular

• nephropathy, neuropathy, retinopathy

• “A strong relationship exists between

glycaemic control and the incidence and

progression of microvascular complications”

• For every 1% reduction in glycatedhaemoglobin concentration there is a 35%

reduction in microvascular disease (T2DM;

estimated)

• Hypertension and smoking also play a role



Nephropathy

• Starts as incipient nephropathy/

microalbuminuria, in which the urine

contains trace quantities of protein

• Not detectable by urinalysis

• ACE inhibitors – renoprotective

• Proteinuria as a marker of widespread

vascular damage

• Increased risk of subsequent end stagerenal disease and macrovascular

complications - CHD



Diabetic Nephropathy Risk

Factors (full list)

• Poor blood sugar control

• High blood pressure

• Smoking

• Relatives have had kidney disease or highblood pressure

• Diabetes began in teens

• Male

• Indo-Asian or Afro-Carribean background



Neuropathy

• commonest form is a diffuse progressive

polyneuropathy affecting mainly the feet

• It is sensory, often asymptomatic, and

affects 40-50% of all patients with diabetes

• Lead to foot ulcers, although aetiology is

mixed with vascular origins

• Foot care advice



Diabetic Foot Ulcer



Diabetic foot ulcer



Diabetic foot ulcer



Retinopathy

• commonest cause of blindness in people

aged 30-69 years

• a combination of microvascular leakage

and microvascular occlusion

• neovascularisation in type 1 diabetes

• maculopathy in type 2 diabetes

• 20% of T2DM patients have some form on

diagnosis• After 15 years almost all patients with

T1DM & 2/3 with T2DM have background

retinopathy.



Maculopathy – types

• exudative maculopathy (when hard

exudates appear in the region of the

macula)

• ischaemic maculopathy (characterised by)

a predominance of capillary occlusion

which results in clusters of haemorrhages)

• oedematous maculopathy (extensive

leakage gives rise to macular oedema)

• Depends on the relative contribution of

leakage or capillary occlusion



Exudative Maculopathy



Ischaemic maculopathy



Oedematous maculopathy



Macrovascular

• Atherosclerotic disease accounts for most of the

excess mortality in patients with diabetes.

• Relationship with glucose concentrations is less

powerful than for microvascular disease

• smoking, blood pressure, proteinuria, andcholesterol concentration are more important risk

factors

• Blood pressure control is very important in

patients with DM!



Coronary heart disease

• Statins have been shown to have a beneficial effect

• Raised risk for diabetics due to aggregation of

earlier factors – high BP, vascular damage, etc

• Prevalence of fatal and non-fatal coronary heart

disease events 2-20 x higher than for non-diabeticsof similar age

• Protective effect of female sex is lost

• Higher incidence of diffuse, multivessel disease

• Plaque rupture leading to unstable angina and

myocardial infarction is more



Myocardial Infarction

• In-hospital and 6 month mortality double that

in non-diabetics

• Complications (eg, arrhythmias, heart failure,

death) more common

• Reperfusion rates after thrombolysis are

similar to those of non-diabetics, but

reocclusion and reinfarction rates are higher

• Mortality reduced by insulin glucose infusion

immediately after myocardial infarction



Stroke

• 85% of acute strokes are atherothrombotic

• Diabetics more at risk of these types of

stroke

• “Patients with diabetes are probably moreprone to irreversible rather than reversible

ischaemic brain damage, and small

lacunar infarcts are common”

• Stroke patients with diabetes have a

higher death rate and a poorer

neurological outcome with more severe

disability



Peripheral vascular disease

• Atheromatous disease in the legs affects

more distal vessels

• This results in multiple diffuse lesions that

are less straightforward to bypass or dilate

by angioplasty.

• Medial calcification of vessels is common

• ABPI is therefore less reliable as a

screening test in patients with diabetes

and intermittent claudication.



Erectile dysfunction

• Multifactorial – autonomic neuropathy,

vascular insufficiency and psychological

factors

• 50% of men aged 50+ (compared with 15-

20% in normal population)

• Probably underreported

• Can cause social and psychological

problems

• Sildenafil - 50-70% success rate



Surveillance and management

• Screening for diabetes

Up to 50% of T2DM patients have vascular

complications on diagnosis

•Eye screening

Mobile retinal photography

• Cardiovascular risk prediction

“Channelling of treatment”



Surveillance and management II

• Annual complications assessment

Should be offered to all diabetics

• Areas of debate in surveillance of diabetes

complicationsDifference between T2 and T1 management

and detection - microalbuminuria

• Team approach to integrated diabetic care

“A systematic, integrated, and collaborativeapproach must be developed at a regional

level”



Predictors of cardiovascular

mortality

Type 1 diabetes Type 2 diabetes

Overt nephropathy Presence of CHD

Hypertension Overt proteinuria

Smoking Glycated haemoglobin

Microalbuminuria Hypertension

Age



Clinical features of "high risk"

diabetic foot

• Impaired sensation (monofilament)

• Past or current ulcer

• Maceration

• Fungal or gryphotic (thickened or horny)toenails

• Biomechanical problems (corns or callus)

• Fissures

• Clawed toes



Fungal toe - progression



Risk of morbidity associated with

all types of diabetes mellitus

Complication Relative Risk

Blindness 20

End stage renal disease 25

Amputation 40

Myocardial infarction 2-5

Stroke 2-3

Vascular Problems in Diabetes

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