Risks: balancing harm and benefit

A Vohrah

When ever considering a test or procedure?

• Is there a better investigation which can give the us the answer? Consider safety, accuracy (sensitivity and specificity), cost, and what is available.

• Is surgery safer or more effective ? Will a radiological approach give similar results over the time period.

The risks

• Radiation dose as a consequence of CT

• Risks of incidental findings-anxiety, further tests with associated morbidity Victim of Modern Imaging Technology (VOMIT).

• False reassurance as a consequence of a scan.

• Complications of interventional radiology

We measure the dose in Sieverts

• 1Sv given to a thousand patients will produce 125 deaths.

• Chest radiograph 0.05mSv (flying to the US is worth about 7CXRs)

• Lumbar spine 2.15mSv• IVU 5mSv• Most tests are 0.5-5mSv• Barium Enema/CT Abdo-pelvis 8-10mSv

(this increases your cancer risk by 1 in 2000)

Cancer Screening in chest

• Second most common tumour in men and third most common in woman. In 2008 the lifetime risk for a man was rated at 1 in14 and a woman 1 in 19.

• Screening would obviously make sense?

• CT could pick up small tumours which potentially were operable.

• In reality 33% False positive rate on CT compared 15% on chest radiographs.

• What do we do with lesions too small for PET CT and too difficult to biopsy.

• What is the mortality and morbidity associated with diagnosis. Biopsies pneumothorax and bleeding. Repeat interval scans –with more radiation

• No one at present is advocating screening for Lung cancer.

Incidental splenic lesion

• MR of lumbar spine due back pain, non resolving.

• Scan showed degenerative change. No intervention required. Incidental splenic lesion noted.

• No history of weight loss.

• Therefore CT scan to characterise the lesion.

• CT inconclusive

• Therefore went on to ultrasound-inconclusive

• Clinically unlikely to be serious in the absence of liver lesions

• Therefore repeat ultrasound to show that there is no evidence of growth.

• Anxiety up all the way over a year due to an incidental finding.

• Could be worse ,if patient can’t live with the anxiety. Biopsy of spleen is risky.

interventional

• Embolisation in vascular

• Dissection in vascular

• Bleeding in vascular

• Discuss chances of success, sometimes surgery is best

• Damage to other surrounding structures.

• EVAR

Consider everday vascularintervention

• 70 year old male, with short distance claudication, bilateral. Previous coronary stenting 5 years previously.

• diabetic.

• Do I do anything? What are his risks in surgery compared to radiological approach.

• Usually most endo vascular procedures carry a serious risk of about 1%.The most serious consequences being limb loss and death.

• In fact we know the risks in more detail in him .The overall mortality for the procedure is 2%.Ranging from 0.2 % with patient suffering claudication to 5% with critical ischaemia.

• Essentially 1.I can introduce infection 2.punch a hole in it or burst it 3.Cause a dissection 4.I can cause emboli to block the artery further down.

Patient became complained of pain, and collapsed

Only lost 200mls of blood but died!

Complications are not always a disaster

Consider another common procedure in interventional radiology-Nephrostomy

What can I damage on introduction?What other problems may occur?

What can I damage?

• Pleura comes over the top of the kidneys, down to 12th rib

• Can introduce infection

• There are major vessels supplying a very vascular structure, there fore bleeding.

• Could still puncture colon , liver, spleen.

• Therefore performed under ultrasound guidance.

Fluoroscopic images

The kidney is puncturedWith the patient in the prone position under ultrasound control

A wire is introduced down the needle.

A tube is pushed over the wire and left in the kidney,

Embolisation of a renal tumour prior to surgery

Occasionally one needs to embolise an AVM or bleeding kidney as a consequence of nephrostomy

EVAR

• What about relatively accepted practise?

• Is it justified?

Image of an aneurysm to discuss suitability

When to operate-well establishedUK small aneurysm trial

• N=2257

• Aneurysms 3-6cm

• Annual rupture rate of 2.2%

• 76% of ruptures >5cms

• Treat over 5.5cm unless symptomatic Risk of rupture>surgery.

What do we know so far?

Operative mortality is lower(1.8 vs 4.3%)Not fit for surgery-30 day mortality is 7.3%. Re

intervention rate is high. Less died of ruptured aneurysm. Overall mortality unchanged.

General mortality advantage over surgery for 1-3 years after repair.

Overall more expensive due to follow up and re intervention.

Stent technology is however improving all the time.So if you are unfit for surgery are we just changing

the modality of death and not prolonging life?