Vascular Final Study Guide Part 3

Virchow's Triad is a concept in medicine that describes the three main factors contributing to the formation of blood clots. These factors include blood stasis, which refers to the slowing or stagnation of blood flow; hypercoagulability, which is an increased tendency for blood to clot; and changes in venous walls, which can make them more susceptible to clot formation. Therefore, the statement that Virchow's Triad relates to blood stasis, hypercoagulability of blood, and changes in venous walls is true.

The given statement is true because the Ankle-Brachial Index (ABI) is calculated by dividing the ankle systolic blood pressure by the brachial systolic blood pressure. In this case, the ankle systolic blood pressure is 110 mm/Hg and the brachial systolic blood pressure is 140 mm/Hg. Dividing 110 by 140 gives us approximately 0.78, which indicates that the AAI (Ankle-Brachial Index) will be about 0.78. Therefore, the statement is true.

The calf muscle pump mechanism works because of the pressure gradient. This is true because the calf muscles act as a pump when they contract, squeezing the veins and pushing the blood upward against gravity. This increases the pressure in the veins and helps to propel the blood back to the heart. The pressure gradient created by the contraction and relaxation of the calf muscles is essential for the efficient functioning of the calf muscle pump mechanism.

The statement is true because hypercoagulability of the blood can indeed be associated with myeloproliferative disorders. Myeloproliferative disorders are a group of conditions characterized by the overproduction of blood cells in the bone marrow. This excessive production of blood cells can lead to an imbalance in the clotting system, resulting in an increased risk of blood clots. Therefore, individuals with myeloproliferative disorders are more prone to developing hypercoagulability, making the statement true.

When a vein is fully distended, it means that it has expanded or stretched to its maximum capacity. In this state, the cross-sectional area of the vein is larger than that of the artery. This is because veins are designed to carry blood back to the heart at a lower pressure compared to arteries, which carry blood away from the heart at a higher pressure. The larger cross-sectional area of veins allows for slower blood flow and lower pressure, which helps prevent damage to the delicate vein walls.

Phlegmasia alba dolens is indeed characterized by severe swelling of the leg. This condition is a rare and severe form of deep vein thrombosis (DVT) that occurs when a blood clot forms in the deep veins of the leg, causing the leg to become pale, swollen, and painful. The swelling is usually accompanied by decreased blood flow and can lead to tissue damage and even gangrene if left untreated. Therefore, the statement "Phlegmasia alba dolens is characterized by severe swelling of the leg" is true.

A false positive in the evaluation of the accuracy of an examination means that the result of the examination is positive, indicating the presence of a condition, but the "gold standard" test, which is considered the most accurate, shows that the condition is actually negative. In this case, it means that the noninvasive ultrasound test showed a positive result, indicating the presence of something abnormal, but the gold standard test showed that there was actually nothing abnormal. Therefore, the statement is true.

Arterial ulcers are caused by poor blood circulation, specifically in the arteries. Due to the reduced blood flow, there is less bleeding associated with arterial ulcers compared to other types of ulcers. This is because the lack of blood supply limits the amount of bleeding that can occur. Therefore, the statement that there is little bleeding with an arterial ulcer is true.

The external iliac veins do not always contain valves. Valves are present in veins to prevent the backflow of blood. While the external iliac veins may have valves in some individuals, it is not a universal characteristic. Therefore, the statement that the external iliac veins always contain valves is false.

Pregnancy and obesity are risk factors for developing varicose veins, but they are not the primary causes. Varicose veins occur when the valves in the veins become weakened or damaged, leading to blood pooling and the veins becoming enlarged and twisted. While pregnancy and obesity can put extra pressure on the veins and increase the likelihood of developing varicose veins, they are not the underlying cause. Other factors such as genetics, age, and prolonged standing or sitting can also contribute to the development of varicose veins.

Venous ulcers do not occur near the lateral malleolus. They typically occur on the lower leg, specifically around the inner ankle and calf. The location of venous ulcers is often associated with poor circulation and venous insufficiency, which can lead to the pooling of blood in the lower legs. This pooling of blood can cause ulcers to develop in areas where the skin is already compromised or under increased pressure, such as the inner ankle and calf. Therefore, the statement that venous ulcers occur near the lateral malleolus is false.

When a person is lying down in a supine position, the hydrostatic pressure in the veins of the leg is indeed approximately 15 mm/Hg. This is because the force of gravity is not acting against the flow of blood, allowing for a relatively low pressure in the veins. This pressure helps to facilitate the return of blood back to the heart.

After eating a high caloric meal, the Doppler waveform pattern in the SMA (superior mesenteric artery) is not highly resistive. This is because a high caloric meal causes the release of digestive hormones that increase blood flow to the intestines, leading to a decrease in resistance in the SMA. Therefore, the correct answer is false.

The statement is false because in regard to venous hemodynamics, the higher the intraluminal pressure, the higher the transmural pressure. Transmural pressure is the difference between intraluminal pressure and extravascular pressure, and it determines the distensibility of veins. When intraluminal pressure increases, the transmural pressure also increases, leading to venous distention.

Chronic hypertension is not a risk factor in the development of DVT. DVT, or deep vein thrombosis, is primarily caused by factors such as immobility, surgery, pregnancy, and certain medical conditions that affect blood clotting. While hypertension can contribute to cardiovascular problems, it is not directly linked to the development of DVT.