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Right-sided Aortic Arch
REFERENCES 1 Skatrud J, Gilbert R, Auchincloss JH Jr, Rana S. Blood clot cast following hemoptysis and resulting in atelectasis [letter]. Chest 1976; 69:131 2 Popovich J Jr, Babcock R. Intraluminal blood clof,casts.causing obstructive emphysema and recurrent pneumothorax. Crit Care Med 1982; 10:482-83 3 Brennan FJ, Parker JO. Check valve airway obstruction by blood clot. Can Med Assoc J 1970; 102:630-31 4 Greenberg JE, Fischl MA, Berger JR. Upper airway obstruction secondary to acquired immunodeficiency syndrome-related Kaposi's sarcoma. Chest 1985; 88:638-39 5 Cole R~ Grossman GJ. Endobronchial streptokinase for bronchial obstruction by blood clots. N Engl J Med 1983; 308:90506 6 Thomson DB. Endobronchial streptokinase to dissolve a right mainstem clot [letter]. Chest 1986; 89:904 7 Kruczek ME, Hoff BH, Keszler BR, Smith RB. Blood clot resulting in ball-valve obstruction in the airway. Crit Care Med 1982; 10:122-23 8 Allen ~ Siefldn AD. Emergency airway clot removal in acute hemorrhagic respiratory failure. Crit Care Med 1987; 15:98586 9 Stewart JH, Olin ~ Graor RA. Thrombolytic therapy: a review (part 1 of 2). Cleve Clin J Med 1989; 56: 189-96 10 Stewart JH, Olin ~ Graor RA. Thrombolytic therapy: a review (part 2 of 2). Cleve Clio J Med 1989; 56:290-96 11 Marder VJ, Sherry S. Thrombolytic therapy: current status (first of two parts). N Eng} J Med 1988; 318:1512-20 12 Marder VJ, Sherry S. Thrombolytic therapy: current status (second of2 parts). N Eng} J Med 1988; 318:1585-95 . 13 Ravilcrishnan K~ Dircks JW Tracheobronchial cast [letter]. Chest 1977; 71:241-42 14 Fairshter RO, Riley CA, Hewlett RI. Large bronchial cast. Arch Intern Med 1979; 39:522-25
Right-sided Aortic Arch 7b the Editor: In the May 1991 issue of Chest, Bose et all report a case of chronic airway obstruction in a 29-year-old woman caused by a right-sided aortic arch. Investigations performed included chest radiography, computed tomography with contrast enhancement, and pulmonary function testing (with methacholine inhalation and intravenous 8uid challenges). The authors speculate that the rJrway compression is due to a vascular cc ring" formed by the right aortic arch (by definition coursing to the right of the trachea) and a cCtighf' ligamentum arteriosum (to the left of the trachea), and conclude that cc surgical division of the ligamentum arteriosum should be curative:' On the basis of the evidence in the report, these statements could be erroneous. The adequate delineation of aortic arch anomalies and vascular rings must include not only the side of the arch but also the brachiocephalic vessel and ductus arteriosuslligamentum arteriosum anatomy. This is highly variable, with specific clinical correlations. The most common aortic arch malformation is a left aortic arch with aberrant right subclavian artery.1(p18) Since all vascular structures (including the ligamentum arteriosum) are to the left of the trachea, no ring is formed, and associated symptoms are rare. Less common are the right aortic arch malformations. Mirro~ image brachiocephalic vessel anatomy is frequently encountered, and is nearly always associated with serious congenital heart disease. 3 The ligamentum arteriosum usually connects the proximal left pulmonary artery and the subclavian portion of the left innominate artery, but in these cases the trachea is not surrounded by vascular or fibrous tissue, and no ring results. A vascular ring can be formed when the ligamentum courses posteriorly from the left pulmonary artery to a descending aortic diverticulum, but this
is extremely rare. !(pSI) The most likely cause of symptoms in the reported case is the combination of right aortic arch with aberrant left subclavian artery (which arises as the most distal branch of the arch). A left-sided IigaJin~n~ 9ften connects this artery to the proximal left pulmonary artery, and a vascular ring is formed. Our investigative approach to the patient with a potential vascular ring includes chest radiography, barium swallow study, and echocardiograph~ Complete anatomic information concerning the arch and brachiocephalic vessels is often obtained through careful ultrasound imaging from the suprasternal notch. Digital subtraction angiography is performed if further information is required. Knowledge of the ligamentum and brachiocephalic vessel relationships is especially important in planning surgery. The tightness of the ligamentum is only one factor in the formation of a vascular ring. While simple division of the ligamentum is often curative in young patients, dissection of surrounding vascular structures may be necessary in adults. There can be significant degeneration of chronically compressed airway walls, and meticulous postoperative respiratory care is required." Complete symptom relief may take weeks.
Niels Giddins, M. D.,
Andrew Pelech, M.D., and Kim Duncan, M.D., F.C.C.l, \&riety Childrem Heart Centre, Winnipeg, Manitoba, Canada
REFERENCES 1 Bose S, Hurst TS, Cockcroft DW Right-sided aortic arch presenting as refractory intraoperative and postoperative wheezing. Chest 1991; 99:1308-10 2 Shuford WH, Sybers RG. The aortic arch and its malformations. Springfield, Ill: Charles C Thomas, 1974 3 Ruckman RN. Anomalies of the aortic arch complex. In: Adams FH, Emmanouilides GC, Riemenschneider TA, eds. Heart disease in infants, children, and adolescents, 4th ed. Baltimore: Williams &: Wilkins, 1989; 26 4 Kirklin ~ Barratt-Boyes BG. Cardiac surgery. New York: Wtley, 1986; 1119
7b the Editor: We agree with Dr Giddins and his colleagues completely. With regard to our specific patient, the definitive study would seem to be angiography ofthe aortic arch and great vessels. Since the patient refused to entertain the idea of surgery, we felt that this procedure was not indicated at the time she was studied.
Donald W Cockcroft, M.D., Department of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
Airway Obstruction by a Mucus Ball from a Transtracheal Oxygen Catheter 7b the Editor: We read with interest in the June 1991 issue of Chest the report by Burton et all on fatal airway obstruction due to mucus ball formation from a transtracheal oxygen catheter, apparently induced by transtracheal oxygen therapy (Tr01T). We report the n~fatal course of mucus ball formation during TT01T in a 28-yeaN>ld Turkish woman, resident in The Netherlands for 15 years. The patient had end-stage pulmonary disease due to pulmonary tuberculosis in childhood, which had been contracted CHEST I 101 I 6 I JUNE, 1992
1739
Right-sided Aortic Arch 7b the Editor: In the May 1991 issue of Chest, Bose et all report a case of chronic airway obstruction in a 29-year-old woman caused by a right-sided aortic arch. Investigations performed included chest radiography, computed tomography with contrast enhancement, and pulmonary function testing (with methacholine inhalation and intravenous 8uid challenges). The authors speculate that the rJrway compression is due to a vascular cc ring" formed by the right aortic arch (by definition coursing to the right of the trachea) and a cCtighf' ligamentum arteriosum (to the left of the trachea), and conclude that cc surgical division of the ligamentum arteriosum should be curative:' On the basis of the evidence in the report, these statements could be erroneous. The adequate delineation of aortic arch anomalies and vascular rings must include not only the side of the arch but also the brachiocephalic vessel and ductus arteriosuslligamentum arteriosum anatomy. This is highly variable, with specific clinical correlations. The most common aortic arch malformation is a left aortic arch with aberrant right subclavian artery.1(p18) Since all vascular structures (including the ligamentum arteriosum) are to the left of the trachea, no ring is formed, and associated symptoms are rare. Less common are the right aortic arch malformations. Mirro~ image brachiocephalic vessel anatomy is frequently encountered, and is nearly always associated with serious congenital heart disease. 3 The ligamentum arteriosum usually connects the proximal left pulmonary artery and the subclavian portion of the left innominate artery, but in these cases the trachea is not surrounded by vascular or fibrous tissue, and no ring results. A vascular ring can be formed when the ligamentum courses posteriorly from the left pulmonary artery to a descending aortic diverticulum, but this
is extremely rare. !(pSI) The most likely cause of symptoms in the reported case is the combination of right aortic arch with aberrant left subclavian artery (which arises as the most distal branch of the arch). A left-sided IigaJin~n~ 9ften connects this artery to the proximal left pulmonary artery, and a vascular ring is formed. Our investigative approach to the patient with a potential vascular ring includes chest radiography, barium swallow study, and echocardiograph~ Complete anatomic information concerning the arch and brachiocephalic vessels is often obtained through careful ultrasound imaging from the suprasternal notch. Digital subtraction angiography is performed if further information is required. Knowledge of the ligamentum and brachiocephalic vessel relationships is especially important in planning surgery. The tightness of the ligamentum is only one factor in the formation of a vascular ring. While simple division of the ligamentum is often curative in young patients, dissection of surrounding vascular structures may be necessary in adults. There can be significant degeneration of chronically compressed airway walls, and meticulous postoperative respiratory care is required." Complete symptom relief may take weeks.
Niels Giddins, M. D.,
Andrew Pelech, M.D., and Kim Duncan, M.D., F.C.C.l, \&riety Childrem Heart Centre, Winnipeg, Manitoba, Canada
REFERENCES 1 Bose S, Hurst TS, Cockcroft DW Right-sided aortic arch presenting as refractory intraoperative and postoperative wheezing. Chest 1991; 99:1308-10 2 Shuford WH, Sybers RG. The aortic arch and its malformations. Springfield, Ill: Charles C Thomas, 1974 3 Ruckman RN. Anomalies of the aortic arch complex. In: Adams FH, Emmanouilides GC, Riemenschneider TA, eds. Heart disease in infants, children, and adolescents, 4th ed. Baltimore: Williams &: Wilkins, 1989; 26 4 Kirklin ~ Barratt-Boyes BG. Cardiac surgery. New York: Wtley, 1986; 1119
7b the Editor: We agree with Dr Giddins and his colleagues completely. With regard to our specific patient, the definitive study would seem to be angiography ofthe aortic arch and great vessels. Since the patient refused to entertain the idea of surgery, we felt that this procedure was not indicated at the time she was studied.
Donald W Cockcroft, M.D., Department of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
Airway Obstruction by a Mucus Ball from a Transtracheal Oxygen Catheter 7b the Editor: We read with interest in the June 1991 issue of Chest the report by Burton et all on fatal airway obstruction due to mucus ball formation from a transtracheal oxygen catheter, apparently induced by transtracheal oxygen therapy (Tr01T). We report the n~fatal course of mucus ball formation during TT01T in a 28-yeaN>ld Turkish woman, resident in The Netherlands for 15 years. The patient had end-stage pulmonary disease due to pulmonary tuberculosis in childhood, which had been contracted CHEST I 101 I 6 I JUNE, 1992
1739