Absence of Left Pulmonary Artery Case report *Dilip Sankhla, Samir Hussein, Jojy George, Ranjan William, Sinan Al-Azawi, Badriya Al-Qassabi case report SQU Med J, August 2009, Vol. 9, Iss. 2, pp. 180-183, Epub 30th June 2009 Submitted - 1st Feb 09 Revision Req. 22nd Apr 09, Revision Recd. 3rd May 09 Accepted - 17th May 09 Department of Radiology and Molecular Imaging, Sultan Qaboos University Hospital, Muscat, Sultanate of Oman. To whom correspondence should be addressed. Email: sankhladilip@gmail.com The unilateral absence of a pulmonary artery is a rare condition with diverse clinical presentations. Routine investigations including chest X-rays and echocardiography may suggest the diagnosis of absence of a pulmonary artery, but confirmation requires computed tomography (CT) scans and magnetic resonance angiography (MRA). An early diagnosis of a unilateral absence of pulmonary artery and appropriate intervention may significantly improve the outcome. We report a rare case of a young woman with a unilateral absence of the left pulmonary artery who presented with a recent history of shortness of breath and chronic cough. Case Report A 21 year old lady was admitted to Sultan Qaboos University Hospital, Oman, via its outpatient clinic, for the evaluation of a small left hemithorax and a mild cough. She had a history of mild attacks of shortness of breath, especially after exertion, and occasional left-sided chest pain. Her symptoms had got worse during the previous year. There was no history of associated fever, sweating, chills, loss of appetite or weight loss. There was no past history of allergy or contact with patients with pulmonary tuberculosis. On examination, she was observed to be in good condition and her vital signs were within normal ranges. Examination of the respiratory system showed a tracheal shift to the left, reduced left chest movements and reduced breath sounds and dull percussion in the left lung. Her chest X-ray [Figure 1] showed evidence of volume loss in the left hemithorax, a mediastinal shift to the left and crowding of the left ribs. The right lung showed compensatory hyperinflation. The left lung showed less vascular marking compared to the right side. The right main pulmonary artery غياب الشريان الرئوي األيسر تقرير حالة دليب شنكال، سامر حسني، جوجي جورج، راجنان وليم، سنان العزاوي، بدرية القصابي عن العيوب اخللقية عادة ما يكون نادر الذكر في التقارير الطبية. يتم تشخيص الناجت األيسر الرئوي الشريان منَو وقصور تخلق امللخص: عدم معظم احلاالت في مرحلة الطفولة، وأحيانا ما تكون هذه احلاالت بدون أعراض ويتم التعرف عليها للمرة األولى في سن البلوغ من خالل أشعة الصدر. نعرض هنا حالة مريضة تبلغ من العمر واحدا وعشرين عاما تعاني من عدم تخلق الشريان الرئوي األيسر الذي كان بدون أعراض حتى البلوغ ، حيث بدأت تعاني من أعراض بسيطة في اجلهاز التنفسي وكانت صورة األشعة السينية للصدر غير طبيعية. ساعد االْسِتْعزازٌ الَتبايُِنّي للتَّْصويُر املَْقَطِعيُّ امُلَوَسب في تأكيد التشخيص. من اجلدير ذكره أن التشخيص املبكر لهذة احلالة املرضية ضروري لتجنب املضاعفات التي ميكن أن تكون قاتلة. مفتاح الكلمات: عدم تخلق الشريان الرئوي وحيد اجلانب ، الشريان الرئوي األيسر ، العيوب اخللقية . تقرير حالة ، عمان. abstract: Agenesis and hypoplasia of left-sided pulmonary artery anomalies have been infrequently reported. The majority of cases are diagnosed in childhood, but occasionally some asymptomatic cases are first recognised in adulthood when detected by an abnormal chest radiograph. We report a twenty-one year old female patient with left pulmonary artery agenesis who was asymptomatic till adulthood, but presented with mild respiratory symptoms and an abnormal chest X-ray. A contrast enhanced computerised tomography )CECT( scan helped to establish the diagnosis. Early diagnosis of this condition is essential to avert potentially lethal complications. Keywords: Unilateral Pulmonary artery agenesis; Left pulmonary artery; Congenital abnormalities; Case report; Oman. Dilip Sankhla, Samir Hussein, Jojy George, Ranjan William, Sinan Al-Azawi and Badriya Al-Qassabi Case Report | 181 was normal and the left was not seen. These findings were suggestive of either a hypoplastic left lung or secondary to chronic obstruction in the left main bronchus. Bronchoscopy, however, revealed normal carina and main bronchi. A pool of secretions was noted in left main bronchus. The bronchial aspirate was negative for acid fast bacilli and its culture was negative. A contrast enhanced computerised tomography (CECT) scan [Figure 2], was performed on this patient to visualise the pulmonary vasculature. It revealed the absence of her left pulmonary artery, a right-sided aortic arch and a dilated main pulmonary artery with evidence of collaterals at the left hilum and in the apical region. The lung parenchyma was normal apart from volume loss of the left lung with compensatory hyperinflation of the right lung. The bronchi on either side were patent. A perfusion-ventilation scan (V/Q) [Figure 3] was also performed. The perfusion scan showed normal perfusion of the right lung and no uptake in the left lung. The ventilation scan showed hypoventilation in the left lung and a normally ventilated right lung. These findings led to the diagnosis of left pulmonary artery agenesis. Discussion The unilateral absence of a pulmonary artery is a rare condition and is believed to originate from a single embryological defect in the proximal sixth aortic arch. It refers to proximal interruption of those vessels, but the vessels are usually intact in the lungs. The incidence is about 1 in 200,000. Left-sided pulmonary artery anomalies have been reported even less frequently. Right pulmonary artery agenesis is twice as common as left pulmonary artery agenesis.1, 2 The majority of cases are diagnosed in childhood, but occasionally some cases with very few symptoms are first recognised in adulthood through the detection of an abnormal chest radiograph. Chest X-rays frequently show a decreased size of the affected hemithorax, compensatory hyperinflation of the contralateral hemithorax, elevation of the ipsilateral hemidiaphragm, absent ipsilateral and enlarged contralateral pulmonary artery shadow, Figure 1: Chest X-ray posterior anterior view shows hypoplastic left lung, decreased vascular markings with ipsilateral mediastinal shift Legend: RPA = right main pulmonary artery; MPA = main pulmonary artery; AA = Aorta Figures 2a & 2b: Contrast enhanced computed tomography axial image (A) and reformatted coronal image (B) shows absence of left pulmonary artery and right-sided aortic arch. Absence of Left Pulmonary Artery Case report 182 | SQU Medical Journal, August 2009, Volume 9, Issue 2 a right-sided aortic arch and an ipsilateral shift of the mediastinum.2, 3, 4 Most of these findings were present in the chest X-ray of our patient. Fallot’s tetralogy, intracardiac septal defects, coarctation of aorta, right aortic arch and Eisenmenger’s syndrome are associated with left pulmonary artery atresia (75%).5 The most common presenting symptoms in patients with pulmonary atresia are recurrent pulmonary infection, mild dyspnea and decrease exercise tolerance.5 Our patient had no major complaints until a year before her admission. In these asymptomatic patients, the blood supply distal to the interruption is provided by a patent ductus arteriosus, bronchial collaterals, and an artery arising directly from the aorta or, less commonly, by transpleural intercostal collaterals.6 Many bronchial collaterals were visible on the CECT of our patient. The presence of a hypoventilated left lung with no perfusion on that side also explains the presence of collateral vessels supplying the left lung. Diminished or total absence of ipsilateral perfusion and normal or mildly reduced ventilation has been reported in the literature.3 This also explains the late onset of her symptoms. The unilateral absence of the pulmonary artery (UAPA) may be suspected by the presence of recurrent respiratory infections, haemoptysis, bronchiectasis or pulmonary hypertension in the absence of other known causes. The parenchymal abnormality is extremely rare. The diagnosis of UAPA can be made by chest radiography and echocardiography. The definitive diagnosis, anatomic details and the presence of hilar collaterals, however, can be discerned by CECT scanning and MR Angiography.7, 8 Cardiac angiography and pulmonary venous wedge angiography have been considered in establishing the diagnosis of UAPA and identifying collateral vessels. However, with the advent of CECT and MR angiography, cardiac catheterisation should be reserved for patients requiring embolisation for recurrent haemoptysis or being considered for revascularisation surgery.4, 5 If sufficiently large hilar arteries are found, revascularisation may significantly improve the outcome. However, large collateral arteries can also lead to pulmonary hypertension or haemoptysis which may require embolisation. The early diagnosis of UAPA and management can avert the above complications and it can also avert the potentially devastating effects of high altitude or pregnancy. Conclusion Agenesis of the left pulmonary artery is a rare anomaly and the patient may remain asymptomatic till adulthood. Imaging plays a major role in the diagnosis and detecting the associated findings in heart and lungs. 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