Swyer syndrome

This is a report of an unusual case of left, predominantly upper lobe, pulmonary edema secondary to paravalvular mitral regurgitation (MR) complicating mitral valve replacement. Transesophageal echocardiography proved helpful in making the diagnosis of MR and suggesting the mechanism of the pulmonary edema.

(CHEST 1998; 114:328-330)

Key words: mitral regurgitation; mitral valve; unilateral pulmonary edema

Unilateral pulmonary edema is relatively uncommon and thus is likely to be confused with other causes of unilateral alveolar and interstitial infiltrates. The specific physiologic mechanisms appear to fall into the same broad categories of the much more commonly recognized bilateral pulmonary edema. These include "cardiogenic" edema with elevation of pulmonary capillary hydrostatic pressure and "noncardiogenic" with decreased plasma oncotic pressure, impaired lymphatic drainage, or disruption of alveolar epithelial-endothelial integrity. We describe a unique case of left, predominantly upper lobe, pulmonary edema secondary to a paravalvular mitral leak complicating mitral valve replacement.

CASE REPORT

A 69-year-old man presented with increasing dyspnea and hemoptysis of 1 week's duration. He had no significant past pleuropulmonary history and had discontinued smoking 30 years prior. His past medical history was significant for hypertension and coronary artery bypass surgery 8 years earlier. Four months prior, he had undergone prosthetic mitral valve replacement (St. Jude) for mitral stenosis via a minimally invasive port-access procedure at another hospital. His course was complicated by arrhythmia requiring placement of a pacemaker on the first postoperative day. Subsequent to surgery he noted no significant improvement in his exercise tolerance. A month later he presented with cough and dyspnea which failed to improve after therapy with oral antibiotics. A chest radiograph at that time revealed a left upper lobe infiltration, and he was admitted for presumed pneumonia. Detailed investigations including bronchoscopy with transbronchial biopsy were unrevealing. He was discharged with a presumptive diagnosis of bronchiolitis obliterans with organizing pneumonia and was receiving systemic corticosteroids. His dyspnea continued to increase, and the steroid dosages were tapered from the initial dose of 60 mg. The dyspnea was worse in the supine and left lateral decubitus position. Failure to respond to a second course of corticosteroids prompted admission to the hospital for further evaluation.

On admission, the patient was dyspneic at rest. His heart rate was 120 beats/min, the respiratory rate was 26 breaths/minute, the BP was 118/80 mm/Hg, and the body temperature was 36.5 [degrees] C. While breathing room air, pulse oximetry was 94%. Examination of the chest revealed well healing surgical scars and crackles in the left upper lung field. There were no rhonchi or evidence of consolidation. The right lung was clear. Examination of the heart revealed a regular rhythm, crisp prosthetic valve sounds, and a soft holosystolic murmur along the left sternal border. There were no gallops. Results of the abdominal examination were normal. The extremities were normal except for 1 + bipedal edema.

The patient had no known drug allergies or significant exposure history. On admission, his medications included enalapril maleate, furosemide, pravastatin, digoxin, Fe[SO.sub.4] tablets, and prednisone. On admission his WBC count was 9.7 X [10.sup.9]/L; hemoglobin, 10.1 g/dL; hematocrit, 30.5%; platelet count, 187 x [10.sup.9]/L; and all chemistry studies were within normal ranges. A chest radiograph (Fig 1) revealed a borderline cardiomegaly, a prominent left pulmonary artery segment, unilateral predominant left upper lobe inhomogeneous "alveolar" infiltrate with perihilar haze and peribronchial cuffing, cephalization, ipsilateral Kerley B lines, and blunting of the left costophrenic sulcus suggesting a small pleural effusion. The CT scan and CT angiogram confirmed the presence of the infiltrate and left effusion and revealed no evidence of thromboembolization or vascular disruption.

[Figure 1 ILLUSTRATION OMITTED]

Transesophageal echocardiography revealed a prosthetic mitral valve dehiscence with severe paravalvular mitral insufficiency. Color flow Doppler imaging (Fig 2) showed the paravalvular regurgitant jet largely directed toward the orifice of the left superior pulmonary vein. Left ventricular function appeared well preserved.

[Figure 2 ILLUSTRATION OMITTED]

DISCUSSION

Unilateral pulmonary edema is an uncommon process that may be frequently confused with other causes of unilateral alveolar and interstitial infiltrates. Although in specific cases the exact physiologic mechanisms may be in doubt, they are believed to fall into the same broad categories of bilateral pulmonary edema with elevation of pulmonary capillary hydrostatic pressure ("cardiogenic"), decreased plasma oncotic pressure or impaired lymphatic drainage or disruption of alveolar epithelial-endothelial integrity ("noncardiogenic").

An additional classification as ipsilateral or contralateral has been suggested by Calenoff et al.[1] Contralateral pulmonary edema occurs on the side opposite a lung with a major perfusion abnormality. It is associated with entities such as unilateral pulmonary thromboembolism, congenital absence/hypoplasia of a pulmonary artery, and Swyer-James syndrome. Ipsilateral pulmonary edema may be seen in the dependent lung with left ventricular dysfunction, acute mitral regurgitation, unilateral veno-occlusive disease, extrinsic pulmonary venous compression (eg, neoplasm), and left-to-right shunt. Noncardiogenic ipsilateral pulmonary edema can be caused by lung reexpansion, aspiration pneumonitis, or surgical or traumatic injury. Contralateral edema can occur with lung resection (lobectomy, pneumonectomy) or unilateral denervation. The relative frequency of these as a cause is unclear but overall heart failure, acute mitral regurgitation, and lung reexpansion appear to be the most commonly reported.[2-11]

Pulmonary edema in a right tipper lobe distribution has been reported with acute mitral regurgitation of the native valve.[2,4,5] Roach et al[2] reported a case with mitral valve regurgitation secondary to a myxomatous flail posterior leaflet and used pulsed Doppler to demonstrate that inflow velocity was greater at the orifice of the right pulmonary vein. In their review of the English-language medical literature, 12 cases of unilateral pulmonary edema were associated with left ventricular failure. In all, the edema was right-sided, and in eight, it was associated with some mitral regurgitation. This was attributed to the direction of regurgitant stream and, perhaps, to superior left lung lymphatic drainage. A variety of unusual mechanisms have been reported including extrinsic compression of a pulmonary vein by aneurysmal dilatation of adjacent aorta or pulmonary artery.[11-13]

As best as can be determined, this is the first case of unilateral pulmonary edema localized to the upper lobes of the left lung reported secondary to paravalvular leak of a prosthetic mitral valve. Subsequent repair of the dehisced valve in the reported patient led to rapid clinical improvement and resolution of the radiologic abnormality. This patient is clinically stable with no evidence of recurrence of the infiltrate 4 months after valve replacement. This case is also instructive in that it emphasizes the need for vigilance for iatrogenic postoperative complications particularly with new surgical techniques. It also demonstrates the utility of a minimally invasive transesophageal echocardiography in establishing the definitive diagnosis and avoiding invasive and unnecessary investigations, as in this case.

References

[1] Calenoff L, Kruglik CG, Woodruff A. Unilateral pulmonary edema. Radiology 1978; 126:19-24

[2] Roach JM, Stajduhar KC, Torrington KG. Right upper lobe pulmonary edema caused by acute mitral regurgitation: diagnosis by transesophageal echocardiography. Chest 1993; 103: 1286-88

[3] Kagele SF, Charan NB. Unilateral pulmonary edema. Chest 1992; 102:1279-80

[4] Gamsu G, Peters DR, Hess D, et al. Isolated right upper lobe pulmonary edema. West J Med 1981; 135:151-54

[5] Gurney JW, Goodman LR. Pulmonary edema localized in the right upper lobe accompanying mitral regurgitation. Radiology 1989; 171:397-99

[6] Poulias GE, Prombonas E. Massive unilateral pulmonary oedema as a rapid re-expansion sequel (the post-expansion syndrome): report of a case and review of the literature. Scand J Thorac Cardiovasc Surg 1974; 8:67-69

[7] Pavlin DJ, Raghu G, Rogers TR, et al. Reexpansion hypotension: a complication of rapid evacuation of prolonged pneumothorax. Chest 1986; 89:70-74

[8] Murphy K, Tomlanovich MC. Unilateral pulmonary edema after drainage of a spontaneous pneumothorax: case report and review of the world literature. J Emerg Med 1983; 1:29-36

[9] Keren A, Tzivoni D, Gottlieb S, et al. Unilateral pulmonary edema complicating acute myocardial infarction. Am J Cardiol 1986; 57:182-83

[10] Snoy FJ, Woodside JR. Unilateral pulmonary edema (down lung syndrome) following urological operation. J Urol 1984; 132:776-77

[11] Cocina EG, Rosas G, Ruiz F, et al. Left ventricular pseudoaneurysm: a cause of unilateral pulmonary edema by compressing the left pulmonary artery. Am Heart J 1996; 132: 1306-07

[12] Takahashi M, Ikeda U, Shimada K, et al. Unilateral pulmonary edema related to pulmonary artery compression resulting from acute dissecting aortic aneurysm. Am Heart J 1993; 126:1225-27

[13] McTigue C, Scurry JP, Silberstein M. Unilateral pulmonary edema associated with pulmonary arterial compression. Australas Radiol 1988; 32:390-93

(*) From the Division of Pulmonary and Critical Care Medicine, Department of Medicine, Long Island Jewish Medical Center, Long Island Campus of the Albert Einstein College of Medicine, New Hyde Park, NY.

Manuscript received October 7, 1997; revision accepted December 19, 1997.

Reprint requests: Leonard J. Rossoff, MD, 270-05 76th Ave, Room C-20, New Hyde Park, NY 11040

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