According to Laplace’s law, a doubling of the radius results in:
W = Pr/2h
here W is circumferential wall stress, P is pressure, r is radius, and h is wall thickness Given this, hypertension, aortic enlargement, and wall thinning are important factors in determining wall stress and therefore progression of aneurysms.
A 33-year-old man is seen in the cardiology outpatient clinic. He is being followed up for aortic regurgitation.
Which one of the following is true?
The ESC valvular heart disease guidelines 2012 recommend the cut-offs shown in Table below for aortic root and aortic valve replacement for patients with any severity of aortic regurgitation (AR).
ESC Guidelines 2012
You see a 60-year-old musician in the outpatient clinic who discharged himself 2 weeks previously following admission with a confirmed type B dissection of the aorta. He tells you that he doesn’t want to take any medication as he prefers natural healing methods. His blood pressure is 180/90 mmHg. He asks you what the future holds for him off medication.
What can you tell him that the data suggest if he has no treatment?
Whilst type B dissections are not as lethal as type A dissections, they are associated with significant mortality if not treated appropriately. Mortality with no treatment is 11% at 1 month, 16% at 1 year, and 20% at 5 years. Approximately a third of survivors of acute dissection experience further dissection or rupture or will require surgery for aneurysm within 5 years. High-risk groups include the elderly, those with poorly controlled hypertension, the presence of a false lumen, larger aortic size, and Marfan syndrome. At presentation, aggressive control of blood pressure to a target of 110 mmHg with IV beta-blockers and sodium nitroprusside infusions is recommended initially, and combinations of beta-blockers, ACE inhibitors, and other antihypertensive medications as outpatients with a less aggressive target of 135/80 mmHg. Maintaining a heart rate of <60 bpm has been shown to be beneficial in preventing complications in type B dissection. Follow-up imaging, usually with CT or MRI, is recommended at 1, 3, 6, 9, and 12 months
Which one of the following statements regarding the choice of imaging in a patient with suspected acute type A aortic dissection is true?
Distal segments of the ascending aorta may not be well seen with TOE as the trachea and left main bronchus pass between the oesophagus and the aorta. TTE has a role in the acute setting but the sensitivity and specificity for accurate diagnosis remain low. Routine chest radiographs are abnormal in 56% of patients with suspected aortic dissection. The sensitivity and specificity of the accuracy of CXR in acute aortic syndromes are 64% and 86%, respectively. These fall when pathology is confined to the ascending aorta. However, a completely normal chest radiograph reduces the likelihood of aortic dissection. In patients with aortic aneurysms, distinguishing a tortuous aorta from an aneurysm is difficult. CT of the aorta is rapidly becoming the investigation of choice for diagnosing acute aortic dissection because of its availability and ease of use. ECG gating can help eliminate false-positive results (e.g. where an intimal flap is mistaken for pulsation artefact). As technology improves, one may anticipate accurate assessment of coronary involvement. Assessment of the aorta with MRI tends to be reserved for follow-up studies because of the time taken for the study. The Surescan device is an MRI-safe pacemaker.
Which one of the following is true regarding CT of the aorta?
Most centres have at least a 16-detector row of CT scanners. There are reports of excellent quality images of coronary arteries using prospective gating in 320-detector row CT. ECG gating helps reduce motion artefacts, particularly in the ascending aorta and for the coronary arteries. The sensitivities of the new generation of multidetector CT scanners are nearing 100% and specificity is 98–99%. It is recommended to scan from the thoracic inlet to the pelvis, including the femoral and iliac arteries (http://circ.ahajournals. org/content/121/13/e266.full.pdf).
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