European Journal of Echocardiography 2007 8(5):403-405; doi:10.1016/j.euje.2006.07.001
Copyright © 2006, The European Society of Cardiology
Acquired pulmonary artery branch stenosis caused by pulmonary thromboembolism
Manjunath Nathan and
Ramdas G. Pai*
Division of Cardiology, Department of Medicine, Loma Linda University Medical Center, Loma Linda, CA, United States
Received 12 May 2006; received in revised form 22 June 2006; accepted after revision 10 July 2006.
rpai{at}usc.edu
* Corresponding author. Division of Cardiology, University of Southern California/Keck School of Medicine, 1510 San Pablo Street, #322, Los Angeles, CA 90033, United States. Tel.: +1 323 442 6130; fax: +1 323 442 6133.
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Abstract
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We present a case of acquired pulmonary artery branch stenosis
caused by pulmonary thromboembolism. The patient presented with
symptoms mimicking aortic dissection. An emergent transesophageal
echocardiogram showed a high gradient across the right pulmonary
artery along with mobile thrombi. The vital importance making
an accurate diagnosis and ruling out aortic dissection is emphasized
in view of the need for urgent heparinization or thrombolysis
for pulmonary thromboembolism as this is contraindicated in
aortic dissection.
Keywords: Pulmonary artery stenosis; Transesophageal Echocardiography; Aortic dissection; Pulmonary embolism; Pulmonary hypertension
Subacute or chronic pulmonary arterial thromboembolism causes pulmonary hypertension and right ventricular hypertrophy, dilatation and failure. Pulmonary arterial luminal narrowing, webbing and abrupt cutoffs are seen on pulmonary contrast or MR angiography and during surgical pulmonary endarterectomy.1,2 However, a focal narrowing of a proximal pulmonary artery (PA) causing a high-grade stenosis detectable by echocardiography has not been described in the literature to our knowledge. We present a patient who presented with symptoms initially suspected due to possible aortic dissection.
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Case history
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A 45-year-old morbidly obese male with no past medical history
presented to the emergency room with acute shortness of breath
and central chest pain radiating to the back. On examination,
the patient was in distress with a heart rate of 105 beats per
minute, blood pressure 170/100mmHg in both arms, and respiratory
rate of 28 per minute. He was afebrile. Examination of the lungs,
heart and abdomen was normal apart from distant heart sounds.
He had 2+ pitting edema of both lower extremities. An electrocardiogram
showed sinus tachycardia and nonspecific ST-T changes. Possibility
of acute aortic dissection was entertained in the emergency
room and transesophageal echocardiogram (TEE) was requested.
The emergently performed TEE showed normal ascending aorta, arch and descending aorta with no evidence of dissection or intramural hematoma. The left ventricular wall motion was normal. The right ventricle was dilated with dilated superior vena cava. There was 2+ tricuspid regurgitation with a TR velocity of 3.5 consistent with an estimated right ventricular systolic pressure of 70mmHg. The main PA was severely dilated with a diameter of 4cm in diastole (Fig. 1). The distal right PA showed severe narrowing with flow acceleration on color flow imaging (Fig. 2). The peak gradient across this narrowing was 36mmHg in systole; with a lesser gradient during diastole (Fig. 3). Further evaluation of the right PA showed multiple mobile masses suggestive of thrombi (Fig. 4). Patient was anticoagulated with heparin. The ventilation/perfusion scan showed bilateral unmatched perfusion defects confirming the diagnosis of multiple pulmonary emboli. He responded to medical therapy and was discharged home a week later on warfarin.
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Figure 3 Continuous wave Doppler velocity profile across the RPA stenosis showing a peak systolic velocity of 3m/s corresponding to a gradient of 36mmHg. There was diastolic antegrade flow with a gradient of 4mmHg.
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Discussion
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We present this patient for the following two reasons: firstly,
to illustrate the unique echocardiographic findings of thromboembolic
pulmonary arterial stenosis with practical tips on its diagnosis;
and secondly, to emphasize the critical importance of suspecting
and accurately diagnosing this entity in patients presenting
with a chest pain syndrome mimicking aortic dissection.
In a patient like ours, it is extremely important to visualize the whole thoracic aorta and demonstrate beyond doubt a possibility of aortic dissection as therapy for this would be an emergent surgery if ascending aorta is involved. On the other hand, pulmonary embolism would require anticoagulation or thrombolytic therapy which would be contraindicated in aortic dissection. Pulmonary arterial branches are best visualized from upper esophageal location above the left atrial level.
Isolated or multiple areas of narrowing of the main PA or its branches has been described, but is a rare de novo finding in the adult. Symptoms mimic those of pulmonary thromboembolic disease, including dyspnea and fatigue. Pulmonary artery stenosis can be congenital or acquired.3,4 Acquired causes are tumors, constrictive pericarditis, tuberculosis, Takayasu's arteritis, aneurysm of aorta or surgery.3,4 Acquired pulmonary artery stenosis caused by pulmonary embolism has not been described in the literature to our knowledge.
In summary, we present a rare case of acquired pulmonary artery branch stenosis caused by pulmonary thromboembolism. The patient presented with symptoms mimicking dissecting aortic aneurysm.
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References
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- Kreitner K.F., Ley S., Kauczor H.U., Mayer E., Kramm T., Pitton M.B., et al. Chronic thromboembolic pulmonary hypertension: pre- and postoperative assessment with breath-hold MR imaging techniques. Radiology (2004) 232:325–326.[Free Full Text]
- Jamieson S.W., Auger W.R., Fedullo P.F., Channick R.N., Kriett J.M., Tarazi R.Y., et al. Experience and results with 150 pulmonary thromboendarterectomy operations over a 29-month period. J Thorac Cardiovasc Surg (1993) 106:116–126.[Abstract]
- Ribera J.M., Torres A., Sasal M., Montserrat J.M., Picado C., Agusti Vidal A. Anaplastic small cell carcinoma of the lung as a cause of acquired stenosis of the pulmonary artery. Pulmonary emboli as initial manifestations. Med Clin (Barc) (1982) 79:428–431.[Medline]
- Tyagi S., Mehta V., Kashyap R., Kaul U.A. Endovascular stent implantation for severe pulmonary artery stenosis in aortoarteritis (Takayasu's arteritis). Catheter Cardiovasc Interv (2004) 6:281–285.
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