Surgical correction of the vena cava-bronchovascular complex Developmental pulmonary, arterial, and venous anomalies with accessory diaphragm

Surgical correction of the vena cava-bronchovascular complex Developmental pulmonary, arterial, and venous anomalies with accessory diaphragm Ronald H. Hayward, M.B., Ch.B., Ph.D.* Jack M. Martt, M.D.,** Luther M. Brewer, M.D.,*** Thomas M. Inmon, M.D.,**** and Edward B. Best, M.D.,***** Temple, Texas

JL/rainage of part or all of the venous return from the right lung to the inferior vena cava constitutes an interesting and rare anomaly. The roentgenographic appearance of this curved descending vein has been described as the scimitar sign. Recently, a report was published of an anomalous vein that manifested this sign but terminated in the left atrium after first sweeping caudally toward the diaphragm. 1 The purpose of this report is to present 2 cases of anomalous venous connection of the right lung. The first illustrates drainage into the inferior vena cava with an associated atrial septal defect and includes a method for surgical correction. The second case demonstrates pulmonary hypoplasia, accessory diaphragm, aberrant arteries, and anomalous venous connection to the

left atrium with only a minor inferior vena

From the Scott and White Clinic, Temple, Texas. Received for publication March 24, 1972. *Department of Cardiovascular Surgery. *'Department of Internal Medicine, Section on Cardiovascular Disease. ♦♦♦Department of Internal Medicine, Section on Pulmonary Disease. **♦♦Department of Internal Medicine, Section on Cardiovascular Disease. ♦♦♦♦♦Division of Radiology, Department of Angiography.

cava communication. It would seem that the latter case completes the spectrum of possible terminations for this peculiar vein and suggests the existence of a developmental complex which also may include an anomalous arterial supply, hypoplasia of the lung, bronchial abnormalities, and an accessory diaphragm. Case reports CASE 1. A 38-year-old Caucasian woman was first examined on July 21, 1969. She complained of exhaustion, heavy breathing, and an occasional feeling of dizziness. The patient had been informed of a heart murmur at the age of 18 years. During the physical examination, a Grade 3 of 6 blowing systolic murmur could be heard over the entire precordium, but the maximum sound was in the second, third, and fourth left intercostal spaces. The second heart sound had a fixed split, and there was a Grade 1 of 6 apical diastolic murmur. Routine laboratory studies provided results which were within normal limits. The chest roentgenogram showed a prominent pulmonary vasculature with a cardiothoracic ratio of 50 per cent. A vertical curved shadow that suggested anomalous pulmonary venous drainage into the inferior vena cava descended along the right heart border (scimitar sign) (Fig. 1, A). The electrocardiographic pattern suggested right ventricular hypertrophy and atypical right bundle branch block. On Sept. 25, 1969, catheterization of the right side of the heart demonstrated an

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Fig. 1. A, Chest roentgenogram (Case 1) showing anomalous vein at right cardiac border. B, Diagrammatic representation of the operative repair. For the purpose of clarity, the commencement of the suture line at the inferior vena cava is not shown. The anomalous vein, its communication, and the atrial septal defect are illustrated. atrial septal defect. The catheter passed up an anomalous vein that joined the inferior vena cava at the diaphragm. Because of these findings and the patient's symptoms surgical correction was recommended. She was operated upon on Sept. 30, 1969. Via a median sternotomy, the right pleural space was opened to isolate the anomalous vein as it entered the vena cava. By partially separating the diaphragm from the vena cava, it was possible to pass a tape around the latter below the site of entry of the anomalous vein. During the dissection, an anomalous artery ascending from the abdomen was found lying in the inferior pulmonary ligament and entering the lower lobe of the right lung. This vessel measured about 3 mm. in diameter. The lung presented the normal three lobes, and there did not appear to be any less-obvious abnormalities. The diaphragm also appeared normal. An arterial cannula was inserted into the right femoral artery, and a venous tube was passed through the femoral vein into the inferior vena cava to a point just below the diaphragm. The superior vena cava was cannulated through the

right atrial appendage, and bypass was started with a flow of 2.4 L. per square meter per minute. Total bypass was achieved by tightening the tape around the superior vena cava and clamping the inferior vena cava against the diaphragm with an angled vascular clamp. The heart was electrically fibrillated, and the anomalous vein was occluded with a bulldog clamp. The right atrium was opened vertically, and the incision was extended down into the anterior aspect of the vena cava. There was a typical secundum atrial septal defect which measured about 2.5 cm. in diameter with a crescentic valve-like border on the superior aspect. The orifice of the anomalous vein could be visualized within the vena cava. A patch of pericardium was sutured to the atrial wall with 3-0 silk to create a tunnel from the orifice of the anomalous vein to the atrial septal defect. The suture line was started at the inferior margin of the anomalous vein where it proved necessary to tie the first knot on the outside of the vena cava (Fig. 1, B). Air was evacuated from the left atrium before completion of the suture line. The patient's convalescence was uneventful. A

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Fig. 2. A, Chest roentgenogram (Case 2) showing a curvilinear density at the right border of the heart and medial to this an anomalous vein. B, An overpenetrated roentgenogram of the heart showing the curvilinear density more clearly. C, Planigram showing the anomalous vein in its course superiorly away from the diaphragm. subsequent roentgenogram of the chest showed a reduction of approximately 50 per cent in the caliber of the anomalous vein, suggesting a decrease in pulmonary blood flow. CASE 2. A 38-year-old Caucasian woman had a history of chronic fatigue, repeated respiratory infections, and asthmatic bronchitis. Several of these attacks had required hospitalization. Results of routine laboratory studies were within normal limits, but a chest roentgenogram showed reduced volume of the right hemithorax. A curved density descending toward the right diaphragm suggested an anomalous vein draining into the inferior vena cava (scimitar sign). A slightly overpenetrated view of the chest showed a

curved linear density extending from the diaphragm superiorly and medially toward the pulmonary hilus. Whether this represented a pleural fold separating a hypoplastic lobe from the remainder of the lung could not be determined, but some poorly aerated tissue was visible medial to this line. These features were clarified by a planigram of the lower lung field, which also showed that the anomalous vein appeared to turn away from the diaphragm toward the mediastinum (Fig. 2). On Feb. 18, 1971, during catheterization of the right side of the heart, a catheter could be passed from the inferior vena cava just below the diaphragm through a small transdiaphragmatic communicating vessel which entered an anomalous

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Fig. 3. A, Roentgenogram showing outline of anomalous vein following direct injection of contrast medium. B, Pulmonary arteriogram showing arterial distribution to right lung.

Fig. 3. Cont'd. C, Aortogram showing anomalous artery to the right lung (arrows). D, Bronchogram showing bronchial tree of right lower lobe. vein in the right lung. Oxygen saturation was 92 per cent in this vein compared with 79 per cent in the right mid-atrium and 81 per cent in the right ventricle. Oxygen saturation in the inferior vena cava was 84 per cent, suggesting the possibility of a very small shunt from this vein. Injection of contrast medium confirmed that the anomalous vein looped inferiorly toward the diaphragm and then turned superiorly with normal entry into the left atrium (Fig. 3, A). The transdiaphragmatic vessel appeared to be only a minor connection to the inferior vena cava, and an atrial septal defect was not found. A pulmonary arteriogram revealed good vascularization of the right

lung except for the inferomedial portion, which did not receive branches of the pulmonary artery. There was no evidence of additional venous drainage from the right lung to the left atrium (Fig. 3, B). A thoracic aortogram demonstrated an anomalous artery that arose from the abdominal aorta and entered the lung via the diaphragm (Fig. 3, C). A bronchogram revealed that bronchi to the right upper and middle lobes were distributed normally but those to the lower lobe appeared to be crowded medially, without evidence of bronchiectasis (Fig. 3, D). During surgical exploration on March 15, 1971, the chest was opened through the bed of the non-

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Fig. 4. A, Photograph taken during surgery showing (1) the accessory diaphragm (held by forceps on each side) and (2) the anomalous vein which receives blood from the lower lobe and superior lobe (fused upper and middle lobes) and terminates in a transdiaphragmatic branch and a large posteriorly directed vein. B, Anomalous vein with transdiaphragmatic branch (right arrow) and main branch draining to the left atrium (left arrow). resected seventh rib. Inspection revealed a single pulmonary lobe which subsequently was shown to represent a fusion of the upper and middle lobes. The lower lobe could be seen lying inferomedially behind a membranous diaphragm, which was attached below and laterally to the normal diaphragm and posteriorly to the ninth rib, and along the mediastinum just beneath the normal pulmonary hilus. The lobe could be inflated only slightly during positive-pressure respiration, and dissection revealed that the pulmonary structures entering this tissue passed through a medial crescentic hiatus in the accessory diaphragm. The latter was opened and peeled from the hypoplastic lower lobe. A large vein in the oblique fissure received tributaries from both lobes, while the confluence formed a large vein measuring about 12 mm. in diameter which descended toward the diaphragm (Fig. A, A). Dissection of the structures that had passed through the accessory diaphragmatic hiatus failed to show any pulmonary arteries; accordingly, the small basilar and superior segment bronchi of the lower lobe were divided and ligated. It was found that the anomalous vein (after making a U turn and giving off a 4 mm. vein through the diaphragm) turned posteriorly through the substance of the hypoplastic lobe and finally entered the left atrium at the normal site for an inferior pulmonary vein to enter (Fig. 4, B). A large artery, measuring 4 to 5 mm. in diameter, penetrated the diaphragm and entered the inferior aspect of the hypoplastic lobe. This was tied during the course of resection, as were three other small aortic tributaries. Following lobectomy, the caval connection was ligated and divided, thereby enabling all venous return from the right lung to pass directly to the left atrium.

The patient's convalescence following this procedure was uneventful, and her pulmonary problems were relieved. Examination of the excised lobe revealed firm, poorly aerated tissue with small alveoli, the walls of which were thickened. The lumina contained many histiocytes. There was an increase of fibrous tissue and hyperplasia of septal cells.

Discussion The syndrome of anomalous venous drainage of the right lung to the inferior vena cava has been well reviewed by Kiely and others.2 The anomaly often has been shown to include an aberrant arterial supply, hypoplasia of a portion of the right lung, and bronchial abnormalities. Surgical correction of this condition was first attained by detaching the anomalous vein, anastomosing it to the right atrium, and then performing an atrioseptopexy. 3 ' 4 Some authors have preferred direct anastomosis to the left atrium in situations in which it could be done without undue tension.5-9 Zubiate and Kay10 redirected the anomalous venous drainage by an intracardiac approach using a tunnel of Teflon. With a cannula in position in the inferior vena cava, however, exposure of the anomalous vein orifice can be awkward, particularly if it is situated well below the right atrium. Apparently, this was not a problem in the case reported by Zubiate and Kay;

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however, Murphy and co-workers11 recently reported a pericardial tunnel repair of anomalous pulmonary venous connection to the inferior vena cava below the diaphragm in which hypothermia and total circulatory arrest were used during placement of the final sutures. The technique described in the present report offers another alternative in situations in which a sufficient length of inferior vena cava can be isolated to allow clamping below the anomalous vein. Venous return from the inferior vena cava then can be obtained by right femoral vein cannulation. Although venous drainage from the right lung to the inferior vena cava is now well documented, communication of this vein with the left atrium has been reported only rarely. Sanger and associates8 described a case in which the vein apparently communicated with both the inferior vena cava and the left atrium through vessels that were probably equal in diameter. The connection with the inferior vena cava was ligated, thus diverting the return of blood to the left atrium. Normal drainage was confirmed postoperatively by angiography. These authors also mentioned another case in which two veins joined the inferior vena cava and one small vessel passed to the left atrium. However, it does not appear that the latter was demonstrated by a contrast study. Mohiuddin and co-workers12 reported a venous connection between the right lung and inferior vena cava, but blood also drained into an accessory venous chamber that lay behind and communicated with the left atrium. Gazzaniga and co-workers13 described a patient in whom the right lower lobe pulmonary veins drained into the inferior vena cava above the diaphragm; however in this case there was communication with the right hepatic vein. From this illustration, it appears that another communication joined this vessel with the right upper lobe pulmonary vein. In this instance, ligation of the anomalous vein above the hepatic connection corrected the condition. Morgan and Forker 1 were the first to re-

port isolated left atrial connection of an anomalous vein demonstrating the scimitar sign. Case 2 of the present report approximates Morgan and Forker's description more closely than any other except for the minor communication with the inferior vena cava. Only isolated reports of accessory diaphragm have appeared in the literature, but the 9 documented cases have been summarized recently by Nazarian and associates.14 One additional case, mentioned by Zubiate and Kay,10 and our case make a total of 11 documented instances of accessory diaphragm. In all except 1 the anomaly was found on the right side.15 In 5 of the collected cases, and in the present report, the accessory diaphragm was fibrous and either divided the lower lobe or separated it from the upper and middle lobes, placing the structure fairly close to the normal diaphragm.10, 15>16 Three of these patients had anomalous venous drainage to the inferior vena cava, 4 had anomalous arteries, and the patient in the present case as well as that of Zubiate and Kay10 showed both aberrations. Two had hypoplastic lower lobes, 1 had normal lungs, and the lung size was not mentioned in the other 2 cases. In the remaining 6 patients, the diaphragm contained a variable quantity of muscle and usually divided or enclosed the lung at a higher level. Anomalous vascular connections were not reported. The occurrence of bronchial abnormalities in patients with this syndrome has been well described by Halasz and co-workers,17 but such anomalies were not detected by bronchography in the 1 patient of the present series so studied. The developmental basis for the vascular abnormalities of the scimitar syndrome has been discussed by Kittle and Crockett.9 When it is understood that the developing vascular plexus surrounding the primitive foregut has free communications between those portions destined to become the pulmonary and systemic venous systems, it is easy to comprehend how certain connections may persist while others disappear ab-

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DRAINAGE TO LEFT ATRIUM (NORMAL) ORAINAGE TO LEFT ATRIUM VIA SCIMITAR VEIN

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Fig. 5. Diagrammatic representation of the spectrum of pulmonary and bronchial anomalies in the described syndrome. The size of arrows and print suggests the developmental frequency of each component.

normally. Although one such anomalous development may drain all or part of the venous return from the right lung into the inferior vena cava, it is conceivable that occasional connections with the left atrium could also develop and persist. The final highways resulting from this plexus might be compared to the changing rays of a spectrum, usually weighted in favor of the inferior vena cava. Occasionally, they reach out for the left atrium to establish a minor or major connection or, rarely, serve this reservoir alone as a result of obliteration or absence of the caval channel. Drake and Lynch16 have presented a possible embryologic explanation for the development of an accessory diaphragm. They theorized that there is a delay in caudal migration of the septum transversum and premature projection of the lung bud. All patients reported to have a low fibrous accessory diaphragm also had anomalous vascular connections. On the other hand, those patients with a more superiorly situated and muscular diaphragm have not had similar vascular anomalies. This would suggest that the vascular connections ac-

tually may have played the role of a "gubernaculum" or tethering mechanism, causing more caudal projection of the lung bud with entrapment of only a small portion of the septum transversum and, hence, a low fibrous diaphragm. Greater impingement of the lung bud on the septum transversum with a high muscular diaphragm may have an entirely different explanation based on deranged timing of both lung bud development and caudal progression of the septum transversum. It is probably more correct to give the latter anatomic result the title of accessory diaphragm, whereas the former is really just a compartmentation of the chest. Kittle and Crockett9 described the vena cava-bronchovascular syndrome as a triad of anomalies which included anomalous pulmonary vein, abnormal bronchi, and abnormal systemic pulmonary arteries. Perhaps an accessory diaphragm and pulmonary hypoplasia should be added to this group. Although the scimitar vein may demonstrate any one of a series of terminations to the left or right side of the heart, it favors the inferior vena cava (Fig. 5 ) . There does not

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seem to be any basis for considering venous obstruction as a cause for the syndrome, as proposed by Massumi and associates,18 unless one is speaking of occlusion or agenesis of venous channels in the early embryo. This, after all, is probably the essence of the developmental alteration. Summary Two cases of right anomalous pulmonary venous connection demonstrating the scimitar sign have been presented. A technique has been described which facilitates repair of anomalous drainage to the inferior vena cava adjacent to the diaphragm. In the patient with pulmonary hypoplasia and accessory diaphragm, the venous drainage was directed circuitously to the left atrium with only a minor communication to the inferior vena cava. It is suggested that this syndrome may comprise a number of developmental anomalies (including pulmonary and bronchial, venous and arterial) and an accessory diaphragm of the low fibrous type. The sites of anomalous venous connections present a spectrum of possibilities but usually favor drainage into the inferior vena cava. These tethering vascular roots may be responsible for the development in some instances of accessory diaphragm of the low fibrous type.

REFERENCES 1 Morgan, J. R., and Forker, A. D . : Syndrome of Hypoplasia of the Right Lung and Dextroposition of the Heart: "Scimitar Sign" With Normal Pulmonary Venous Drainage, Circulation 4 3 : 27, 1971. 2 Kiely, B., Filler, J., Stone, S., and Doyle, E. F.: Syndrome of Anomalous Venous Drainage of the Right Lung to the Inferior Vena Cava: A Review of 67 Reported Cases and Three New Cases in Children, A m . J. Cardiol. 20: 102, 1967. 3 Kirklin, J. W., Ellis, F . H., Jr., and Wood, E. H.: Treatment of Anomalous Pulmonary Venous Connections in Association With Interatrial Communications, Surgery 39: 389, 1956. 4 Gilman, R. A., Skowron, C. A., Musser, B. G., and Bailey, C. P.: Partial Anomalous Venous Drainage, Am. J. Surg. 94: 688, 1957.

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5 Risch, F . , and Hahn, C. H. S.: The Technique of Surgical Correction of Anomalies of the Pulmonary Veins in a Series of 25 Cases, Thorax 13: 251, 1958. 6 Ehrenhaft, J. L., Theilen, E. O., and Lawrence, M. S.: T h e Surgical Treatment of Partial and Total Anomalous Pulmonary Venous Connections, Ann. Surg. 148: 249, 1958. 7 Koch, W., and Silva, A.: Anomalous Drainage of Pulmonary Veins Into the Inferior Vena Cava: Importance of Planigraphic Study, Radiology 75: 592, 1960. 8 Sanger, P. W., Taylor, F . H., and Robicsek, F.: The Scimitar Syndrome, Arch. Surg. 86: 580, 1963. 9 Kittle, C. F . , and Crockett, J. E.: Vena CavaBronchovascular Syndrome—A Triad of Anomalies Involving the Right Lung: Anomalous Pulmonary Vein, Abnormal Bronchi and Systemic Pulmonary Arteries, Ann. Surg. 156: 222, 1962. 10 Zubiate, P., and Kay, J. H.: Surgical Correction of Anomalous Pulmonary Venous Connection, Ann. Surg. 156: 234, 1962. 11 Murphy, J. W., Kerr, A . R., and Kirklin, J. W.: Intracardiac Repair for Anomalous Pulmonary Venous Connection of Right Lung to Inferior Vena Cava, Ann. Thorac. Surg. 11: 38, 1971. 12 Mohiuddin, S. M., Levin, H . S., Runco, V., and Booth, R. W.: Anomalous Pulmonary Venous Drainage. A Common Trunk Emptying Into the Left Atrium and Inferior Vena Cava, Circulation 34: 46, 1966. 13 Gazzaniga, A. B., Matloff, J. M., and Harken, D. E . : Anomalous Right Pulmonary Venous Drainage Into the Inferior Vena Cava and Left

Atrium,

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57: 251, 1969. 14 Nazarian, M., Currarino, G., Webb, W. R., Willis, K., Kiphart, R. J., and Wilson, H. E.: Accessory Diaphragm: Report of a Case With Complete Physiological Evaluation and Surgical Correction, J. THORAC. CARDIOVASC. SURG.

61: 293, 1971. 15 Davis, W . S., and Allen, R. P.: Accessory Diaphragm: Duplication of the Diaphragm, Radiol. Clin. North A m . 6: 253, 1968. 16 Drake, E. H., and Lynch, J. P . : Bronchiectasis Associated With Anomaly of the Right Pulmonary Vein and Right Diaphragm, J. THORAC. SURG. 19: 433, 1950.

17 Halasz, N . A., Halloran, K. H., and Liebow, A. A.: Bronchial and Arterial Anomalies With Drainage of the Right Lung Into the Inferior Vena Cava, Circulation 14: 826, 1956. 18 Massumi, R. A., Alwan, A. O., Hernandez, T. J., Just, H. G., and Tawakkol, A. A.: The Scimitar

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