Total Anomalous Pulmonary Venous Return

Transcription

1 Total Anomalous Pulmonary Venous Return Correlation of Hemodynamic Observations and Surgical Mortality in 58 Cases Robert D. Leachman, M.D., Denton A. Cooley, M.D., Grady L. Hallman, M.D., James W. Simpson, M.D., and Wayne E. Dear, M.D.* T otal anomalous pulmonary venous return is a rare though important cardiac malformation. In this disorder the pulmonary venous blood is delivered to the right atrium by direct connection, via the coronary sinus, or to the systemic venous drainage through either the superior or inferior vena caval systems. The systemic arterial blood flow is thus dependent upon an intraatrial communication or a patent ductus arteriosus. Untreated, the mortality of this defect is approximately 80% during the first two years of life [2, 51. Total anomalous pulmonary venous return ranks fourth among the cyanotic congenital heart lesions requiring surgical intervention during infancy at the Texas Children s Hospital [3]. Total anomalous pulmonary venous return may be diagnosed clinically and confirmed by cardiac catheterization and angiography. Congestive heart failure that usually responds poorly to medical therapy is the most common indication for surgical intervention. In an effort to predict surgical risk and, hence, to provide a logical basis for selection of patients for surgical treatment, hemodynamic data from patients with total anomalous pulmonary venous return have been reviewed. CLINICAL MATERIAL AND RESULTS Fifty-eight patients with total anomalous pulmonary venous return were studied by cardiac catheterization and subsequently operated upon between 1956 From the Department of Medicine and the Cora and Webb Mading Department of Surgery, Baylor University College of Medicine, and the Texas Heart Institute of the Texas Children s and St. Luke s Episcopal Hospitals, Houston, Tex. Supported in part by U.S. Public Health Service Grants (HE HE-05387, and HE-05435). *Dr. Dear was a Post-Doctoral Fellow of the National Heart Institute (I-F3 HE ) during the preparation of this paper. Accepted for publication July 30, Address reprint requests to Dr. Hallman, 1200 Moursund Ave., Houston, Tex

2 I- LEACHMAN ET AL. and The group included 30 males and 28 females ranging in age from 5 days to 35 years. Right heart catheterization was performed using only local anesthesia in patients less than 1 year of age and in those over 12 years of age. Patients from 1 through 11 years typically received sedative doses of a barbiturate. Right heart pressures were obtained with Statham transducers, displayed on an Electronics for Medicine multichannel oscilloscope, and recorded photographically. Blood oxygen saturations were determined with a Waters oximeter cuvette; patients breathed room air. The nature of the anomaly required the approximation of mixed systemic venous blood oxygen saturations from the mean of the superior vena caval saturation distal to the shunt and twice the value of the inferior vena caval saturation obtained below the diaphragm. In a few instances samples of systemic venous blood from the superior vena caval system could not be obtained, and the inferior vena caval blood was used to estimate mixed venous oxygen saturation. Systemic arterial pressure and blood oxygen saturations were determined by a Riley needle in either the femoral or brachial artery. FACTORS IN SURGICAL RISK The surgical mortality for the entire group was 41%. Analysis of data indicated that survival was directly related to age, pulmonary vascular resistance, and severity of cyanosis. Age. Surgical risk was distinctly greater in patients less than 1 year of age, as shown in Table 1. Among patients in this group, 19 of 27 died following surgery (surgical mortality, 70%). No patient less than 7 weeks of age survived. Among the 31 patients over 1 year of age, there were only 5 deaths (surgical mortality, 16%). Pulmonary Vascular Resistance. This has been suggested as the factor which limits survival of the patient with total anomalous pulmonary venous return [l, 2, 131. The relative pulmonic and systemic pressures and flows were employed to estimate pulmonary vascular resistance. Flow ratios were calculated by subtracting the percent mixed venous blood oxygen saturation (MV) from the percent systemic arterial blood oxygen saturation (Ao) and dividing by the difference of the percent blood oxygen saturations observed in the pulmonary venous trunk (PV) and the pulmonary artery (PA). When direct measurement of pulmonary venous saturation was not possible, this blood was assumed to be 95% saturated with oxygen. AO - MV Flow ratio = PV - PA Pressure ratios were calculated from the difference between mean pressures recorded in the pulmonary artery (PAP) and right atrium (RAP) or the mean pulmonary capillary wedge pressure (PCWj3 divided by mean systemic arterial pressure (SF) less mean right atrial pressure (RAF). Mean left atrial and right atrial pressures were observed to be essentially equal. PAP - PCWP Pressure ratio = Sp - RAP The approximate normal pulmonic-to-systemic resistance ratio is 0.2 [l, 9, 131. As seen in Table 2, 21 of 34 patients with elevated pulmonary vascular resistance died (surgical mortality, 62%), while among those of this series with normal pulmonary vascular resistance, only 3 of 24 died (surgical mortality, 13%). When the ratios of pulmonic-to-systemic flow are plotted against those of pulmonic-to-systemic pressures, the importance of pulmonary vascular resistance in determining surgical risk becomes clear. Figure 1 presents these data in patients less than 1 year of age. Seventeen of 21 patients less than 1 year of age with high 6 THE ANNALS OF THORACIC SURGERY

3 Total Anomalous Venous Return TABLE 1. AGE AND SURGICAL MORTALITY IN TOTAL ANOMALOUS PULMONARY VENOUS RETURN No. of No. of Surgical Patients Deaths Mortality Less than 1 year % Over 1 year % Total % TABLE 2. PULMONIC-TO-SYSTEMIC RESISTANCE RATIO AND SURGICAL MORTALITY IN TOTAL ANOMALOUS PULMONARY VENOUS RETURN Pulmonic-Systemic Resistance Ratio No. of No. of Surgical Patients Deaths Mortality Greater than % Less than % pulmonary vascular resistance died (surgical mortality, 80%), while 2 of the 6 in the same age group but with normal pulmonary vascular resistance died (surgical mortality, 33%). Figure 2 presents the same ratios in patients over 1 year of age. In this group, 4 of 13 patients with elevated pulmonary vascular resistance died (surgical mortality, S1%), while only 1 of 18 with low resistance died (surgical mortality, 5%). Cyanosis. Severity of cyanosis also correlated with surgical mortality. Patients with a systemic arterial blood oxygen saturation greater than 85% or pulmonary arterial blood oxygen saturation greater than 89% had a decreased surgical mortality. This is presented in Figure 3. With oxygen saturations below these arbitrary levels, the surgical mortality was 55%, whereas with oxygen saturations above these levels, the surgical mortality was only 14%. These values HIGH PULMONARY VASCULAR RESISTANCE MORTALITY : 17 I21 * 80 PER CENT a 9 PULMONARY RATIO OF ~ SYSTEMIC FIG. 1. Relationship of pulmonic-to-systemic vascular resistance in patients less than 1 year of age. Pulmonic-to-systemic Pressure, ordinate; pulmonic-tosystemic flow, abscissa; iso-resistance ratio at 0.2, normal. The figures above the line represent patients with an elevated pulmonary vascular resistance. VOL. 7, NO. I, JAN.,

4 LEACHMAN ET AL. HIGH PULMONARY VASCULAR RESISTANCE MORTALITY : PER CENT RATIO OF!$:?$ FIG. 2. Relationship of pulmonic-to-systemic vascular resistance in patients over I year of age. Pulmonic-to-systemic pressure, ordinate; pulmonic-to-systemic flow, abscissa; iso-resistance ratio at 0.2, normal. Figures above the line represent patients with elevated pulmonary vascular resistance. relate indirectly to pulmonary vascular resistance, since systemic and pulmonic arterial blood oxygen saturations reflect the volume of pulmonary blood flow. Since the systemic arteriovenous oxygen difference is a crude index of total systemic flow, the arteriovenous oxygen differences in these patients were reviewed. A difference of greater than 20% usually indicates poor systemic cardiac output. Figure 4 shows these data for the patients less than one year of age; Figure 5 presents these data for the older group. Note that in both groups the arteriovenous blood oxygen saturation (A-V) differences were, in the main, below the 20% level, indicating a normal cardiac output. There was no correlation between the A-V difference and surgical mortality. FLOW 100% 90% 80% -,o MORTALITY 3/22 = 14% 0 A % 0 70% 60% A A MORTALITY = 54% ++ MORTALITY 3121 * 14 % I 1 1 I 1 FZG. 3. Severity of cyanosis and surgical mortality in total anomalous pulmonary venous return. Pulmonary arterial blood oxygen saturation, ordinate; systemic arterial blood oxygen saturation, abscissa; perpendicular intersects at 89 and 85%, respectively. 8 THE ANNALS OF THORACIC SURGERY

5 Total Anomalous Venous Return 0 I I I I I 1 5% 10% 15% % 30%,ARTERIOVENOUS OXYGEN SATURATION DIFFERENCE FIG. 4. Systemic arteriovenous oxygen saturation differences in patients less than I year of age. The age in months is shown on the ordinate, while the difference in arteriovenous oxygen saturation is plotted on the abscissa. A perpendicular is placed at the 20% level ARTER IOVENOUS OXYGEN SATURATION DIFFERENCE FIG. 5. Systemic arteriovenous oxygen saturation differences in patients over 1 year of age. The age in years is shown on the ordinate, while the difference in arteriovenous oxygen saturation is plotted on the abscissa. A perpendicular is placed at the 20% level. VOL. 7, NO. 1, JAN.,

6 LEACHMAN ET AL. DISCUSSION The high surgical mortality in patients with total anomalous pulmonary venous return operated upon during the first year of life is consistent with previous reports [4, 7, 111. The poor prognosis for infants having this malformation, even with surgical treatment, might be dismissed by attributing it to general underdevelopment, poor nourishment, the frequent presence of acute respiratory tract infections, and intractable pulmonary congestion. Some of these seriously ill infants, however, tolerate operations well and have a postoperative course similar to older patients. Although surgical risk is greater for infants less than 1 year old, age alone is not the sole determinant of surgical mortality for the individual patient. The factor of greatest prognostic significance appears to be pulmonary vascular resistance. There is a clear correlation between high pulmonary vascular resistance and increased surgical risk. The frequency with which elevated pulmonary vascular resistance is encountered in the younger group (19 of 27 patients) as contrasted to the group over 1 year of age (5 of 31 patients) is significant. Whether infants with increased pulmonary vascular resistance typically die or, rather, pulmonary vascular resistance decreases with age is unknown and remains a topic for speculation. Retarded regression of pulmonary vascular resistance, however, has been observed in patients with ventricular septa1 defects and might occur in patients with total anomalous venous return [8]. As has been noted previously, histological study of the lung in patients with total anomalous pulmonary venous return and elevated pulmonary vascular resistance demonstrates persistence of the fetal pattern in the pulmonary arteries long after it should have regressed [12]. In one of the infants with high resistance, the pulmonary venous drainage entered the portal vein, and the interposition of the hepatic vascular bed contributed to the elevated resistance. Stenosis of the common pulmonary venous trunk was not demonstrated in any of the patients in this series. The measurement of essentially equal right and left atrial pressures at catheterization and subsequent observation of relatively large intraatrial communications (typically, a patent foramen ovale) at surgery are consistent with the report of Hastreiter et al. [6]. It seems unlikely that intraatrial obstruction contributed significantly to the observed resistance ratios in this group of patients. Miller et al. [lo] recently have reported the beneficial application of interatrial septostomy in five critically ill infants with total anomalous pulmonary venous return and associated pulmonary arterial hypertension with congestive heart failure; these patients were reported to have a pressure gradient be- 10 THE ANNALS OF THORACIC SURGERY

7 Total Anomalous Venous Return tween the right and left atria. A two-stage surgical approach has been used by Mustard et al. [ll] without modification of overall mortality in a larger series. An intact atrial septum with right-to-left communication via a patent ductus arteriosus [6] was not seen in this group of patients. Severity of cyanosis is a useful sign in the clinical evaluation of patients with total anomalous pulmonary venous return. Since both the systemic and pulmonary venous returns mix in the right atrium, the oxygen saturation of this pooled blood reflects the proportions of pulmonary and systemic blood flow; the greater the pulmonary blood flow, the higher the oxygen saturation of the right atrial blood. It should be emphasized that systemic arterial blood oxygen saturation reflects the volume of pulmonary blood flow and is thus related indirectly to the pulmonary vascular resistance. The intensity of cyanosis may therefore serve as a clinical index of surgical risk. Inadequate left ventricular volume has been proposed as an important determinant of surgical mortality [7], and pathological examination has been said to show relative diminution of left ventricular volume [6]. In the presence of a small cavity, it would be reasonable to anticipate reduced systemic blood flow. In the patients in this series, the observed normal or reduced systemic arteriovenous oxygen difference is inconsistent with a reduced systemic cardiac output due either to a small left ventricular cavity or to limitation of flow by a small foramen ovale. The paradox of congestive heart failure with normal arteriovenous blood oxygen saturation differences permits speculation as to the presence of a form of high output failure. Further observations, perhaps employing cardiac output estimations, will be required to clarify this point. SUMMARY Hemodynamic observations in 58 surgically treated patients with total anomalous pulmonary venous return were reviewed and analyzed for possible prognostic value. The overall surgical mortality for this group was 41%. Survival was directly related to age, pulmonary vascular resistance, and severity of cyanosis. Patients under 1 year of age had a surgical mortality of 70%, while in those over 1 year, it was 16%. In patients with elevated pulmonary vascular resistance (pulmonary arterial-to-systemic arterial resistance ratio greater than 0.2), the observed mortality was 62%, but in patients with pulmonary vascular resistance less than 0.2, the mortality was only 1.3%. Patients with systemic arterial oxygen saturations above 85% had a surgical mortality of 14%, and in those with saturations below these levels, the mortality was 55%. The most unfavorable group consisted of patients less than VOL. 7, NO. 1, JAN.,

8 LEACHMAN ET AL. 1 year of age with high pulmonary vascular resistance; their mortality was 80%. Patients older than 1 year of age with low pulmonary vascular resistance had 95% survival. REFERENCES 1. Burchell, H. B. Total anomalous pulmonary venous drainage: Clinical and physiologic patterns. Proc. Mayo Clin. 31: 161, Burroughs, J. T., and Edwards, J. E. Total anomalous pulmonary venous connection. Amer. Heart J. 59:913, Cooley, D. A., and Hallman, G. L. Surgery during the first year of life for cardiovascular anomalies: A review of 500 consecutive operations. J. Cardiovasc. Surg. 5:584, Cooley, D. A., Hallman, G. L., and Leachman, R. D. Total anomalous pulmonary venous drainage. J. Thorac. Cardiovasc. Surg. 51 :88, Darling, R. C., Rothney, W. B., and Craig, V. M. Total pulmonary venous drainage into the right side of the heart. Lab. Invest. 6:44, Hastreiter, A. R., Paul, M. H., Molthan, M. E., and Miller, R. A. Total anomalous pulmonary venous connection with severe pulmonary venous obstruction. Circulation 25:916, Keith, J. D., Rowe, R. D., Vlad, P., and O Hanley, J. H. Complete anomalous pulmonary venous drainage. Amer. J. Med. 16:23, Leachman, R. D., Lien, W. P., and McNamara, D. G. Serial hemodynamic study of thirty-two patients with isolated ventricular septa1 defects. Amer. J. Cardiol. (Abstract) 21:107, Lucas, R. V., Jr., St. Geme, J. W., Jr., Anderson, R. C., Adams, P., Jr., and Ferguson, D. J. Maturation of the pulmonary vascular bed. Amer. J. Dis. Child. 101:467, Miller, W. W., Rashkind, W. J., Miller, R. A., Hastreiter, A. R., Green, E. W., Golinko, R. J., and Young, D. Total anomalous pulmonary venous return: Effective palliation of critically ill infants by balloon atrial septotomy. Circulation 36: 11, Mustard, W. T., Keith, J. D., and Trusler, G. A. Two-stage correction for total anomalous pulmonary venous drainage in childhood. J. Thorac. Cardiovasc. Surg. 44:477, Rosenberg, H. S., McNamara, D. G., and Colin, C. D. Pulmonary arteries and changes in blood flow. Arch. Path. (Chicago) 76:177, Swan, H. J. C., Toscano-Barboza, E., and Wood, E. H. Hemodynamic findings in total anomalous pulmonary venous drainage. Proc. Mayo Clin. 31:177, THE ANNALS OF THORACIC SURGERY