UKOM Sp.DVE flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Poiseuille's law

Flow through a cylindrical vessel is proportional to the fourth power of radius and the pressure gradient, and inversely proportional to viscosity and length. Small radius reductions markedly increase resistance.

Virchow triad

Three factors predisposing to thrombosis: venous stasis, endothelial injury, and hypercoagulability. It explains DVT, access-graft thrombosis, and many arterial thromboses.

Ankle-brachial index

Ratio of ankle systolic pressure to brachial systolic pressure. Values ≤0.90 suggest peripheral arterial disease; >1.30 suggests medial calcinosis requiring toe-brachial index or waveform assessment.

Toe-brachial index

Ratio of toe systolic pressure to brachial pressure; normal ≥0.70. Useful when ankle arteries are calcified and the ankle-brachial index is falsely elevated.

Duplex ICA velocity criteria

Peak systolic velocity >125 cm/s suggests ≥50% internal carotid stenosis; >230-250 cm/s with end-diastolic velocity >100 cm/s suggests ≥70%. Ratios to common carotid velocity improve accuracy.

Rutherford claudication categories

Rutherford 1-3 denote mild, moderate, and severe claudication; 4 is rest pain; 5 minor tissue loss; 6 major tissue loss. Category 0 is asymptomatic.

TASC II classification

Anatomical classification of aortoiliac and femoropopliteal lesions (A-D). Focal type A/B lesions favour endovascular therapy; extensive type C/D lesions favour open bypass.

Critical limb-threatening ischaemia

Rest pain lasting more than two weeks, or ulceration/gangrene, with ABPI <0.4 or toe pressure <30 mmHg. High risk of amputation without revascularisation.

AAA repair threshold

Elective repair is considered at diameter ≥5.5 cm in men or ≥5.0 cm in women, growth >1 cm/year, or when symptomatic. Rupture risk rises steeply above these sizes.

Stanford type A dissection

Dissection involving the ascending aorta, regardless of distal extent. It is a surgical emergency because of risk of tamponade, coronary malperfusion, and aortic rupture.

Crawford extent II TAAA

Thoracoabdominal aortic aneurysm involving most of the descending thoracic and abdominal aorta. It carries the highest risk of spinal cord ischaemia and paraplegia.

CEAP classification

Clinical (C0-C6), Etiology (congenital, primary, secondary), Anatomy (superficial, deep, perforator), Pathophysiology (reflux, obstruction, both). Standardises chronic venous disease description.

Venous reflux threshold

Valve closure time >0.5 seconds in superficial veins and >1.0 second in deep veins on duplex defines reflux. Perforator reflux is defined as >0.35 seconds.

Post-thrombotic syndrome

Chronic pain, swelling, hyperpigmentation, and ulceration after deep vein thrombosis due to venous hypertension. Elastic compression stockings reduce incidence and severity.

Lymphedema management

Complex decongestive therapy: manual lymphatic drainage, multilayer compression, exercise, and skin care. Diuretics are not effective and may worsen the condition.

Hard signs of arterial injury

Pulsatile bleeding, expanding haematoma, absent distal pulses, bruit or thrill, and distal ischaemia. These mandate immediate exploration or angiography.

Rutherford class IIb ALI

Immediately threatened limb with rest pain, sensory loss, and motor deficit; arterial and venous Doppler signals may be inaudible. Requires immediate revascularisation or amputation.

Compartment syndrome

Pain out of proportion and pain on passive stretch after reperfusion or trauma. Urgent fasciotomy prevents myonecrosis and permanent nerve injury.

Rule of 6s for AVF

A mature arteriovenous fistula has flow ≥600 mL/min, diameter ≥6 mm, depth ≤6 mm, and is at least 6 weeks old. It predicts successful cannulation.

Steal syndrome

Distal hypoperfusion after access creation causing pain, coolness, or tissue loss. Treated with banding, DRIL procedure, or proximalisation of inflow.

Seldinger technique

Percutaneous vascular access: needle puncture, guidewire insertion, needle removal, then catheter or sheath over the wire. Confirm wire position before dilation.

ALARA principle

Radiation exposure should be kept as low as reasonably achievable. Achieved with pulsed fluoroscopy, collimation, last-image hold, and minimal magnification.

Drug-coated balloon

Balloon delivering antiproliferative drug (e.g., paclitaxel) to the vessel wall during angioplasty. Reduces restenosis in femoropopliteal disease compared with plain balloons.

Carotid endarterectomy indication

Symptomatic ≥70% internal carotid stenosis benefits most; 50-69% has moderate benefit. Timing within two weeks of symptoms improves outcomes.

Protamine reversal

Reverses unfractionated heparin; approximately 1 mg protamine per 100 units of heparin given. Risk of hypotension and anaphylaxis with rapid administration.

Surgical safety checklist

WHO checklist with sign-in, time-out, and sign-out phases. Consistent use reduces surgical morbidity and mortality and improves team communication.

Statin therapy in PAD

Indicated for all patients with peripheral arterial disease regardless of baseline LDL. High-intensity statins reduce cardiovascular events and improve walking distance.

Heparin-induced thrombocytopenia

Platelet drop >50% or thrombosis 5-10 days after heparin exposure. Stop heparin, start argatroban or bivalirudin, and avoid platelet transfusions.

Informed consent

Valid consent requires capacity, adequate disclosure of material risks and alternatives, and voluntariness. The discussion and decision must be documented.

Duty of candour

An ethical and often legal obligation to disclose harm to patients openly, apologise, and explain what will be done. Applies to individuals and organisations.

PDSA cycle

Plan-Do-Study-Act: iterative quality improvement method. Each cycle tests a small change, measures the effect, and informs the next cycle.

Evidence hierarchy

Systematic reviews and meta-analyses of randomised trials rank highest, followed by individual randomised trials, cohort studies, case series, and expert opinion.