|Number 16-09: Subarachnoid Hemorrhage Unmasks Aortic Coarctation In A Young Man|
Number 16-09: Subarachnoid Hemorrhage Unmasks Aortic Coarctation In A Young Man
Case from: Tayeb Rahim, MS3, Clint Walters, MD, Aamisha Gupta, MD, Jayanth Keshavamurthy, MD, William B. Bates, MD, and Gyanendra Sharma, MD
Institution: Augusta University, Augusta, GA, United States
A 20-year-old male with a history of hypertension presented to the emergency department because of a severe headache. On examination, the patient was confused and disoriented. His BP was 135/61 mmHg, temperature 35.6°C (97.9°F), pulse 78, and respiratory rate 24. Cardiovascular exam showed a regular heart rhythm, a grade III/VI diastolic murmur heard best in the third left intercostal space, strong pulse, no edema, warm skin, and capillary refill of < 3 seconds. No lower extremity blood pressures were obtained.
EKG suggested left ventricular hypertrophy and showed tall T-waves and ST-elevations (Figure 1).
Brain CT scan showed a subarachnoid hemorrhage due to a ruptured basilar tip aneurysm. Patient underwent coil embolization, and a right frontal ventricular drain was placed.
The chest x-ray showed the figure "3 sign" as well as rib notching (Figure 3).
Chest CT revealed coarctation of the aorta, the narrowest portion measuring 7.9 mm in diameter at the proximal descending aorta (Figures 4 (left) and 5 (right)).
The ascending thoracic aorta measures 39 mm in diameter (Figure 6 (left)), and the descending aorta distal to the stenosis measures 22 mm in diameter (Figure 7 (right)).
Volume-rendered images demonstrate prominent internal thoracic and intercostal arteries (Figures 8 (left) and 9 (right)).
CMR findings: Note: to see the full CMR study please visit the following link:
A 3T MRI scanner was used to obtain the following results.
CE-MRA: Numerous collateral intercostal arteries associated with ribs 4 - 9. Large anastomotic collateral between the left subclavian and the T8 intercostal artery. Volume-rendered images demonstrate prominent internal thoracic and intercostal arteries along with a moderate-sized spinal artery originating immediately distal to the coarctation (Figure 10).
Balanced steady-state free precession imaging: The aortic valve appears like a true bicuspid valve, with fusion of the right coronary and left-coronary aortic cusps and a small rudimentary raphae (Figure 11). Normal right and left ventricular function. Normal left ventricular ejection fraction. There was no evidence of delayed myocardial enhancement to suggest a myocardial scar. The ejection fraction was 55% (borderline low), left ventricular end diastolic volume was 85.4 ml/m2 (normal), and the left ventricular end systolic volume was 38.1 ml/m2 (high). The end diastolic left ventricle wall mass was 91.5 gr/m2 (high).
Velocity-encoded cine MR imaging:There was a pressure gradient across the coarctation relative to the aortic arch that was not accurately quantified due to technical difficulties. There was moderate aortic regurgitation of 44%.
The patient underwent cardiac catheterization with stent placement in the coarcted segment. Pressure measurements during catheterization were 85/40 in the ascending aorta and 65/50 in the descending aorta with a 20 mmHg peak gradient between the two.
EKG (Figure 12) and echo were performed after the procedure. Echo now demonstrates only mild to moderate aortic regurgitation.
Clinicians should maintain a certain degree of suspicion for coarctation of the aorta in young patients presenting with hypertension. Once clinical signs are identified, imaging can be used to diagnose aortic coarctation evaluate for other associated anatomic abnormalities that put the patient at risk for development of chronic conditions such as heart failure or acute conditions such as intracranial hemorrhage. The baseline degree of stenosis associated with the coarctation can be documented, and patients can then be appropriately managed to prevent future morbidity and mortality. MRI is very useful in such patients as it allows one to non-invasively assess the anatomic and functional integrity of the heart and great vessels, without any risk of radiation exposure. MRA can be used to visualize and measure the severity of the coarctation as well as to map out any compensatory collateral pathways that have formed. Velocity-encoded cine MR imaging allows us to measure peak flow velocities at different points along the aorta to assess the maximum gradient. We can then use these measurements to derive the pressure gradient across the coarctation. Using a fully refocused steady-state sequence, we can visualize the heart at different phases of the cycle with very little motion artifact, allowing us to identify other associated anatomic abnormalities or compromises to cardiac function. It is also a useful tool for evaluating left ventricular ejection fraction and left ventricular mass.
The presence of hypertension in children can often be attributed to an underlying cause, such as renal parenchymal disease or coarctation of the aorta. An identifiable cause is less often found in adolescents and even less so in young adults. Common etiologies of secondary hypertension in the young adult age group include thyroid dysfunction, fibromuscular dysplasia, and renal parenchymal disease (1). If present, coarctation of the aorta is frequently discovered during childhood. It is less common for it to be left undiagnosed until adulthood.
Case prepared by Associate Editor: Lilia M. Sierra Galan, MD