Coronary angiography—small arterial catheters are maneuvered from a femoral artery puncture site through the femoral artery and aorta and up to the origins of the coronary vessels. X-ray contrast medium is then injected to demonstrate the coronary vessels and their important branches. If there is any narrowing (stenosis), angioplasty may be carried out. In angioplasty tiny balloons are passed across the narrowed areas and inflated to refashion the vessel and so prevent further coronary ischemia and myocardial infarction.
A 53-year-old man presented to the emergency department with a 5-hour history of sharp pleuritic chest pain and shortness of breath. The day before he was on a long haul flight, returning from his holidays. He was usually fit and well and was a keen mountain climber. He had no previous significant medical history.
On physical examination his lungs were clear, he was tachypneic at 24/min, and his saturation was reduced to 92% on room air. Pulmonary embolism was suspected and the patient was referred for a CT pulmonary angiogram. The study demonstrated clots within the right and left main pulmonary arteries. There was no pleural effusion, lung collapse, or consolidation.
He was immediately started on subcutaneous enoxaparin and converted to oral anticoagulation over the course of a couple of days. The whole treatment lasted 6 months as no other risk factors (except immobilization during a long haul flight) were identified. There were no permanent sequelae.
The embolic material usually originates in the peripheral deep veins of the lower limbs and less commonly in the pelvic, renal, or upper limb deep veins. The material gets detached from the main thrombus in the deep veins and travels into the pulmonary circulation, where it can lodge either in the pulmonary trunk and main pulmonary arteries, giving rise to central pulmonary embolism or in the lobar, segmental, or subsegmental branches, giving rise to peripheral embolism.
The gravity of symptoms is partly dependent on the thrombus load and on which part of the pulmonary arterial tree is affected. Large pulmonary embolisms can lead to severe hemodynamic and respiratory compromise and death (e.g., a saddle thrombus lodged in the pulmonary trunk and in both main pulmonary arteries).
Common risk factors include immobilization, surgery, trauma, malignancy, pregnancy, oral contraceptives, and hereditary factors.
A young man has black areas of skin on the tips of his fingers of his left hand. A clinical diagnosis of platelet emboli was made and a source of the emboli sought.
Emboli can arise from many sources. They are clots and plugs of tissue, usually platelets, that are carried from a source to eventually reside in small vessels which they may occlude. Arterial emboli may arise in the heart or in the arteries that supply the region affected. In cases of infected emboli, bacteria grow on the valve and are showered off into the peripheral circulation.
A neck radiograph and coronal CT image of the neck demonstrates a cervical rib (eFig. 3.116).
Cervical ribs may produce three distinct disease entities:
Arterial compression and embolization—the cervical rib (or band) on the undersurface of the distal portion of the subclavian artery reduces the diameter of the vessel and allows eddy currents to form. Platelets aggregate and atheroma may develop in this region. This debris can be dislodged and flow distally within the upper limb vessels to block off blood flow to the fingers and the hand, a condition called distal embolization.
Tension on the T1 nerve—the T1 nerve, which normally passes over rib I, is also elevated by the presence of a cervical rib; thus the patient may experience a sensory disturbance over the medial aspect of the forearm, and develop wasting of the intrinsic muscles of the hand.
Compression of the subclavian vein—this may induce axillary vein thrombosis.