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* From the Department of Internal Medicine II (Drs. Lange, Luchner, Endemann, Pfeifer, and Schulz), University of Regensburg, Regensburg, Germany; and the Department of Cardiology (Dr. Pitschner), Kerckhoff-Klinik GmbH, Bad Nauheim, Germany.
Correspondence to: Tobias J. Lange, MD, Department of Internal Medicine II / Division of Pneumology, Hospital of the University of Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany; e-mail: tobias.lange{at}klinik.uni-regensburg.de
A 46-year-old man presented with recurrent hemoptysis, dyspnea on exertion (New York Heart Association II score), and episodes of cough. Symptoms first occurred 3 years ago, about 3 months after undergoing minimally invasive mitral valve repair for treatment of mitral regurgitation. The patient gave a history of pulmonary embolism, which was diagnosed on the basis of findings of a radionuclide lung scan that had been conducted shortly after the onset of symptoms. He denied having a fever, night sweats, weight loss, allergies, contact with pets, or exposure to toxic substances. He was a former cigarette smoker (40 pack-years). He was receiving therapy with a proton pump inhibitor because of gastroesophageal reflux disease and a history of a peptic ulcer. Anticoagulation had been discontinued several months before because of recurrent hemoptysis.
Physical Examination
The patient was an athletic-appearing man (weight, 83 kg; height, 183 cm) with no significant findings except for a grade 2/6 systolic murmur at the cardiac apex. Laboratory data showed a normal CBC count, and routine blood chemistry and coagulogram findings. Test results of rheumatoid factor and cytoplasmic and perinuclear antineutrophil cytoplasmic antibodies were negative. Arterial blood gas testing showed a pH of 7.41, a PCO2 of 34.4 mm Hg, and a PO2 of 77.9 mm Hg. Pulmonary function revealed normal ventilation and diffusing capacity of the lung for carbon monoxide; the results of bronchial provocation testing were negative. A chest radiograph showed increased interstitial markings in the right upper and middle lobes. The CT scan of the chest is shown in Figure 1 . Transthoracic echocardiography showed normal right and left heart function at rest, and a slight residual mitral valve regurgitation after mitral valve repair. Bronchoscopy demonstrated hyperemic tissue around the bronchi of the right upper and right middle lobes (Fig 2 ); no tumor was detected. BAL fluid revealed no lymphocytosis or malignant cells; microscopy and cultures were negative. Histology of the transbronchial biopsy specimens from the right upper and middle lobes showed a marked increase in hemosiderin-laden alveolar macrophages, but no active inflammation, granulomas, or malignancy. Since histologic findings suggested a cardiac etiology of the patient’s symptoms, a transesophageal echocardiogram was performed to establish the diagnosis (Fig 3 ).
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Diagnosis: Subtotal right upper pulmonary vein stenosis, most likely caused by scarring as a complication of minimally invasive mitral valve repair performed 3 years ago
Discussion
With this operation, one method for opening the left atrium is to perform an incision immediately adjacent to the right upper pulmonary vein (PV), which is the leading structure for anatomic orientation using this approach. This report appears to be the first to describe PV stenosis (PVS) following minimally invasive mitral valve surgery.
More commonly, PVS is seen as a complication of radioablation for atrial fibrillation. The rate is actually 1 to 2%, ranging from < 1% up to 38% depending on the ablation technique used, the center experience, the approach to diagnosis (ie, screening vs symptom-diagnosed), the definition of stenosis, the follow-up interval, and the diagnostic method used. The main symptoms of PVS, which in the majority of patients occur between 1 and 3 months after undergoing the ablation procedure, are dyspnea on exertion, cough, pleuritic chest pain, and, less frequently, hemoptysis. The occurrence of symptoms was found to be associated with the involvement of severe stenosis of more than one PV. On the other hand, even patients with occlusion of a PV may be asymptomatic. Radiologic abnormalities, as seen in the presented case, are not normally observed but can lead to false diagnoses such as pneumonia or lung cancer. Furthermore, patients often receive a misdiagnosis of pulmonary embolism due to the perfusion defects seen on ventilation/perfusion scanning in those with severe PVS or occlusion.
Imaging methods used for screening of PVS after radioablation include MRI and transesophageal echocardiograpy, but CT scanning also can be helpful in establishing the diagnosis in symptomatic patients. Radionuclide lung scans were found to be able to assess the functional significance of PVS in a screening population since all patients with severe stenosis (
70%) had perfusion defects in the corresponding segments. In a study of 11 patients who were referred for the evaluation of suspected PVS, perfusion defects were found only in the six patients with stenosis of > 80% and a left atrial PV pressure gradient of > 5 mm Hg. Thus, ventilation/perfusion scanning was suggested as a screening tool for PVS after radioablation. However, this test cannot distinguish between pulmonary embolism and PVS because perfusion defects are caused by a reduction in blood flow in both cases and the images appear to be very similar. Another method for detecting perfusion defects in patients with PVS is magnetic resonance perfusion imaging, which shows a better correlation with symptoms than does the grade of stenosis defined by MRI alone.
The therapy of PVS is difficult and not standardized. Angioplasty is a therapeutic option with immediate symptom relief, but restenosis rates are high at about 50%. Additional stenting seems to be superior to balloon angioplasty alone; however, restenosis in, or next to, the stent may occur. Systematic data on drug-eluting stents or surgical therapy in this setting is not available.
The decision about if and when asymptomatic patients should be treated can be challenging. There are reports that have found no progression of MRI-diagnosed PVS over > 2 years; other authors have reported progression of PVS even into PV occlusion after a median follow-up period of 3.2 months. Others have suggested treatment of PVS of 70%, irrespective of symptoms because of the unknown risk of the development of pulmonary hypertension or lesion progression. Pulmonary hypertension at rest is not commonly seen in patients with PVS or even in those with PV occlusion, but it has been observed during exercise in some patients. Furthermore, even patients in whom pulmonary hypertension did not develop failed to show the physiologic decrease in pulmonary vascular resistance (PVR) with exercise on right heart catheterization.
Clinical Course
The patient in the case presented here also underwent right heart catheterization to assess the contribution of mitral regurgitation to the dyspnea and hemodynamic consequences of PVS. We measured normal values at rest (mean pulmonary artery pressure, 15 mm Hg; mean pulmonary capillary wedge pressure, 9 mm Hg; mean PVR, 71 dyne · s · cm–5), but there was a slight pulmonary hypertension during exercise (mean pulmonary artery pressure, 30 mm Hg). This was explained mainly by a rise in pulmonary capillary wedge pressure to 18 mm Hg, whereas there was no decrease in PVR (92 dyne · s · cm–5), as would have been expected under normal hemodynamic conditions.
Our differential diagnoses included pulmonary embolism, interstitial pneumonia, cryptogenic organizing pneumonia, and lung cancer. The patient was referred for angioplasty of the right upper PV, but unfortunately the vein was found to be virtually occluded on catheterization, and angioplasty failed (Fig 4 ). Currently, the patient is awaiting surgery.
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Footnotes
The authors have reported to the ACCP that no significant conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.
Received for publication December 7, 2006. Accepted for publication January 23, 2007.
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