Intrathoracic extramedullary hematopoiesis simulating anterior mediastinal tumor.

Intrathoracic extramedullary hematopoiesis is a rare tumor occurring predominantly in the posterior mediastinum, most commonly in patients with congenital hemolytic anemias. The first reported case of this entity's occurring in the anterior mediastinum is described in a 68-year-old man with an incompletely characterized anemia. Definitive diagnosis was established only after median sternotomy and removal of the tumor.

Myocardial protection during prolonged aortic cross-clamping. Comparison of blood and crystalloid cardioplegia.

We compared the ability of blood and crystalloid cardioplegia to protect the myocardium during prolonged arrest. Twelve dogs underwent 180 minutes of continuous arrest. Group I (six dogs) received 750 ml of blood cardioplegic solution (potassium chloride 30 mEq/L) initially and every 30 minutes. Group II (six dogs) received an identical amount of crystalloid cardioplegic solution (potassium chloride 30 mEq, methylprednisolone 1 gm, and 50% dextrose in water 16 ml/L of electrolyte solution). Temperature was 10 degrees C and pH 8.0 in both groups. Studies of myocardial biochemistry, physiology, and ultrastructure were completed before arrest and 30 minutes after normothermic reperfusion. Biopsy specimens for determination of adenosine triphosphate were obtained before, during, and after the arrest interval. Regional myocardial blood flow, total coronary blood flow, and myocardial oxygen consumption were statistically unchanged in Group I (p greater than 0.05). Total coronary blood flow rose 196% +/- 49% in Group II (p less than 0.005), and left ventricular endocardial/epicardial flow ratio fell significantly in this group from 1.51 +/- 0.18 to 0.8 +/- 0.09, p less than 0.01 (mean +/- standard error of the mean. The rise in myocardial oxygen consumption was not significant in this group (34% +/- 36%, p greater than 0.05). Ventricular function and compliance were statistically unchanged in both groups. In Group II, adenosine triphosphate fell 18% +/- 3.4% (p less than 0.005) after 30 minutes of reperfusion; it was unchanged in Group I. Ultrastructural appearance in both groups correlated with these changes. We conclude that blood cardioplegia offers several distinct advantages over crystalloid cardioplegia during prolonged arrest.

Preservation of myocardial ATP. Comparison of blood vs crystalloid cardioplegia.

Preservation of myocardial high-energy phosphates correlates with the heart's ability to resume normal function following aortic crossclamping (AXC). The ability of the canine myocardium to synthesize and maintain ATP during 180 minutes of AXC was evaluated in 12 hearts subjected to either blood or crystalloid cardioplegic arrest. Group 1 hearts were arrested by infusion of 750 ml of blood potassium cardioplegia (BKC) solution into the aortic root initially and every 30 minutes, as were group 2 (six) hearts but with a crystalloid cardioplegia (CC) solution. Transmural left ventricular biopsy specimens were obtained for ATP analysis prior to AXC (control), before and after cardioplegia injections 2, 4, and 6, prior to unclamping (180 minutes of AXC), and 30 minutes following reperfusion. ATP levels increased significantly above control (p less than 0.005) during the 180 minutes of AXC immediately following infusion of BKC. At the end of 180 minutes of AXC and following 30 minutes of reperfusion, ATP was noted to be normal in this group (p = NS). In contrast, ATP levels fell significantly (p less than 0.005) during the period of aortic cross-clamping in the crystalloid cardioplegia group and did not return to normal even after 30 minutes of reperfusion (p less than 0.005). We concluded that BKC, by presenting the arrested myocyte with adequate oxygen and substrate, allows for synthesis and preservation of myocardial ATP during periods of AXC as long as three hours. In this respect, it should be regarded as superior to CC, which permits a statistically significant depletion of ATP (p less than 0.005) uncorrected, even after 30 minutes of reperfusion in the beating, nonworking state.

Cardiac output determination after cardiac operation. Lack of correlation between direct measurements and indirect estimates.

Ninety-two mean thermodilution cardiac indices were determined in 25 patients following cardiac operations. Arterial and venous blood gases, hematocrit, body temperature, central venous pressure, left atrial pressures, urine output, heart rate, and mean arterial pressure were simultaneously recorded. Six variables, arterial and venous pH, arterial and venous PCO2, venous PO2, and temperature, showed significant simple correlations with cardiac index, but the degree of correlation was inadequate for use of these variables as reliable indices of cardiac function. When stepwise multiple regression analysis was performed, two variables, venous PO2 and left atrial pressure were associated with the best correlation with cardiac index, such that CI = 0.073 PO2V -- 0.060 LAP + 1.39 (r = 0.60, p less than 0.001). When measured values for venous PO2 and left atrial pressure were substituted into this equation, a "predicted" value for cardiac index could be obtained with only slightly improved reliability. The data indicate that indirect estimation of cardiac output by measurement of the various laboratory parameters described above is not sufficiently reliable for clinical use. The importance of obtaining direct measurements of cardiac output by thermodilution or other means in order to properly evaluate postoperative cardiac function is stressed.

Left atrium-to-femoral artery bypass: effectiveness in reduction of acute experimental myocardial infarction.

The effects of prompt institution of left atrium-to-femoral artery (LA-FA) bypass on myocardial infarct area (AI) as a percentage of myocardial area at risk for infarction (AR) during a 4 hour period following ligation of the left anterior descending coronary artery (LAD) were studied in 26 dogs. Following LAD ligation, baseline measurements of myocardial tension-time index (TTI) and regional myocardial blood flow (RMBF) were obtained. Group I (controls, n = 16) received no further support. Group II (LA-FA bypass, n = 10) underwent left ventricular unloading via LA-FA bypass beginning 15 minutes after coronary occlusion. Four hours after LAD occlusion, measurements of TTI and RMBF were repeated in both groups. Just before sacrifice, gentian violet was injected into the aortic root to delineate the AR. The hearts were then removed and sectioned transversely through the left ventricle (LV) and septum. The AR (that ventricular area not perfused by gentian violet) was measured by planimetry and compared to the AI as identified by incubation of heart slices in triphenyltetrazolium chloride dye. In comparisons of control versus LA-FA bypass groups, both AI/LV (21.6% versus 10.4%) and AI/AR ratios (73.7% versus 21.8%) were significantly reduced in the bypass group (p less than 0.005). Mortality in the control group (5/16, 31.2%) was significantly greater (p less than 0.005) than in the bypass group (0/10, 0%). Mean TTI over the 4 hour ischemic period was essentially unchanged in the control group as compared to a reduction of 62.8% in the bypass group (p less than 0.005). Furthermore, RMBF at 4 hours was significantly improved in all regions of the LV in hearts undergoing LA-FA bypass when compared with control hearts (p = 0.025). These results demonstrate by a consistent method that prompt institution of LA-FA bypass significantly reduces the mortality associated with acute coronary artery occlusion, as well as the total AI and AI/AR. The protective mechanisms provided by LA-FA bypass probably include the highly significant reduction of LV work and the opening of new bridge collateral blood vessels with redistribution of blood flow to the ischemic region.

The factors influencing early patency of coronary artery bypass vein grafts: correlation of angiographic and ultrastructural findings.

To test the hypothesis that suboptimal preparation of saphenous veins may adversely affect early patency of aorta-coronary artery bypass grafts, a nonrandomized prospective study was undertaken comparing two methods of saphenous vein preparation prior to grafting. Forty recatheterizations were performed during the postoperative hospital stay (approximately 10 days) in two groups of asymptomatic patients who had undergone isolated coronary artery bypass grafting. Veins from patients in Group I were bathed in autologous, heparinized blood at 20 degrees C and distended to 80 mm Hg, prior to grafting. The veins from Group II patients were prepared in an identical manner, except that the bathing solution consisted of heparinized electrolyte solution with added papaverine (0.6 mg/lg). Segments of vein from each group were obtained prior to grafting and preserved in 3% glutaraldehyde for subsequent electron microscopic studies. Operative technique in both groups of patients was identical and all procedures were performed by the same surgeons. Comparison of patients in Group I and II revealed no significant difference in the number of diseased vessels per patient (3.1 versus 3.4), number of grafts per patient (2.9 versus 2.9), native vessel diameter (1.9 versus 1.7 mm), and postoperative graft flows (65 versus 68 cc/min). However, early postoperative graft patency in Group II patients was 93% versus 80% in patients in Group I (p less thn 0.01). Electron microscopic analysis revealed severe spasm of venous smooth muscle in the blood-stored veins causing intraluminal smooth muscle cell cytoplasmic protrusions with resultant endothelial separation and desquamation. Formation of fibrin-platelet microaggregates was common. These findings were not present in the solution-treated veins. In view of these ultrastructural findings, and the highly significant difference in patency rates, we have abandoned all blood storage techniques and now prepare saphenous veins by soaking them in a clear bathing medium with added heparin and papaverine. Long-term follow-up of these patients is currently in progress and may reveal even more dramatic results than we have heretofore observed.

Surgical treatment of primary lung cancer and solitary intracranial metastasis.

From 1976 through 1986, 12 patients underwent 14 thoracotomies (two patients had a second thoracotomy for recurrence) and 16 craniotomies (two patients had three craniotomies for recurrence) for carcinoma of the lung and solitary intracranial metastasis. Age ranged from 40 to 65 years. Adjuvant therapy (chemotherapy and thoracic irradiation) was employed in three patients prior to thoracotomy and in four patients following thoracotomy. Whole-brain irradiation was used in four patients after craniotomy. Improvement in neurologic symptoms following craniotomy was noted in 15 of 16 instances. There were no operative mortalities. Overall survival from the time of initial diagnosis ranged from 13 to 63 months. Survival following initial craniotomy ranged from 12 to 56 months. Eight patients are currently alive and well with no disabling neurological symptoms. These results support an aggressive approach to the resection of solitary brain metastasis from bronchogenic carcinoma, both for palliation and prolongation of survival.

'Pulsatile' left atrial-femoral artery bypass. A new method of preventing extension of myocardial infarction.

A left atrial-femoral artery (LA-FA) bypass system was designed to deliver synchronous pulsatile blood flow. We compared it with nonpulsatile LA-FA bypass in its effectiveness to limit infarct extension after ligation of the left anterior descending coronary artery at its origin in 35 dogs. Nonpulsatile LA-FA bypass resulted in a 70% reduction in the size of infarct. The addition of synchronous diastolic counterpulsation (P-LA-FA) further reduced the size of infarct, when compared with that in controls (95%) or animals that underwent LA-FA bypass (83%). Both LA-FA and P-LA-FA bypasses limited infarct extension and reduced mortality after acute coronary occlusion through effective unloading of the left ventricle. The addition of diastolic counterpulsation to LA-FA bypass led to further significant infarct reduction, when compared with LA-FA bypass alone. These effects were most likely secondary to improvements in myocardial blood flow distribution.

Blood potassium cardioplegia administration. Comparison of myocardial protection offered by three techniques.

To investigate the best method of administration of blood potassium cardioplegia, 19 dogs were studied while undergoing 120 minutes each of aortic crossclamping (myocardial temperature, less than 15 degrees C). Group 1 (six dogs) underwent a single 120-minute period of aortic crossclamping with the heart protected by multiple reinjections (1,000 mL every 30 minutes) of blood potassium cardioplegia solution (potassium chloride, 30 mEq/L; pH, 8; temperature, less than 15 degrees C). Group 2 (six dogs) underwent four separate 30-minute periods of aortic crossclamping, but allowing hearts to beat in a nonworking state for 20 minutes at 35 degrees C between each arrest interval. Hearts in group 3 (seven dogs) were initially arrested as described above, following which a continuous infusion (75 mL/min; KCl, 10 mEq/L) of blood potassium cardioplegia solution was maintained throughout the arrest period. Measurements of myocardial metabolism, ventricular function, regional blood flow, and ultrastructure were carried out before arrest and 30 minutes after final unclamping. Analysis of the data revealed no significant benefit of one method over another, with the exception that adenosine triphosphate level was least preserved with intermittent unclamping and reperfusion. Because continuous perfusion techniques are more cumbersome than multidose reinjection, and intermittent aortic crossclamping lengthens total cardiopulmonary bypass time, we favor the simplest approach, multidose reinjection during a single uninterrupted period of aortic crossclamping.

Tuberculous esophagitis with aortic aneurysm fistula.

A patient with treated pulmonary tuberculosis and a thoracic aortic aneurysm was seen with a one-month history of dysphagia. Barium swallow revealed a mass in the lower esophagus and extravasation of contrast material into the mediastinum. Endoscopy and biopsy specimens showed acid-fast organisms. The patient was treated with antituberculous drug therapy but bled massively from the gastrointestinal tract and died. Autopsy revealed an aortoesophageal fistula at the level of the thoracic aneurysm. Histopathological study confirmed that this rare tuberculous lesion of the esophagus caused the fistula.

Myocardial protection with cold blood potassium cardioplegia during prolonged aortic cross-clamping.

The efficacy of cold blood potassium cardioplegia during periods of aortic cross-clamping (greater than 100 minutes) was assessed in 127 patients undergoing a variety of open-heart surgical procedures at New York University Medical Center from january, 1978, to April, 1979. Ischemic intervals ranged from 100 to 267 minutes (mean, 128 minutes). Cardiac-related deaths occurred in only 3 patients (2.4%), and overall operative mortality was 8.7% (11 patients). The rate of perioperative infarction was 10%. Fourteen patients (11%) required vasopressor support or balloon counterpulsation after cardiopulmonary bypass despite the lengthy cross-clamp intervals. Multivariate analysis revealed no significant relationship between the length of cross-clamp time and operative mortality (p = 0.29), incidence of perioperative infarction (p = 0.54), or the occurrence of low-output syndrome postoperatively (p = 0.68). These findings suggest that cold blood potassium cardioplegia provides adequate myocardial protection when periods of arrest as long as 3 to 4 hours are required for complex cardiac surgical procedures.

Early open radical commissurotomy: surgical treatment of choice for mitral stenosis.

Between 1967 and 1979, 411 patients underwent surgical treatment of isolated mitral stenosis at our institution. Open radical mitral commissurotomy was performed in 150 patients (1967-1978; mean follow-up, 46 months; range, 4 to 116 months). Mitral valve replacement using a porcine prosthesis was performed in 74 patients (1976-1979; mean follow-up, 23 months; range, 2 to 48 months). Mitral valve replacement with a cloth-covered Starr-Edwards prosthesis was performed in 187 patients (1967-1975; mean follow-up, 45 months; range, 2 to 106 months). Preoperative characteristics were similar in the three groups. The open commissurotomy and Starr-Edwards groups were followed up to 9 years and the porcine valve group up to 4 years, with 97% follow-up in each group. Life-table analysis (6-month intervals) of all postoperative complications revealed significantly greater complication-free survival for patients who had open radical commissurotomy compared with Starr-Edwards (p less than 0.05) valve replacement. Similar analysis of thromboembolic and warfarin-related complications revealed significantly fewer complications in commissurotomy patients. No significant differences were found (p greater than 0.05) when comparing the need for subsequent reoperation in each group. Operative mortality following open radical mitral commissurotomy (0%; 0 out of 150) was significantly less (p less than 0.05) than after mitral valve replacement in both porcine (8.1%; 6 out of 74) and Starr-Edwards (11.2%; 21 out out 187) groups. Life-table analysis of late cardiac-related mortality revealed a significantly greater cumulative survival rate for the commissurotomy versus the Starr-Edwards groups at all intervals from 12 to 108 months (100 versus 84 +/- 5%, p less than 0.05). No significant differences were noted between commissurotomy and porcine valve groups during the 4-year follow-up period (100 +/- 0% versus 96 +/- 3%, p greater than 0.05). Based on these findings, we conclude that when the anatomy is favorable, the surgical treatment of choice for isolated mitral stenosis is open radical mitral commissurotomy.

Increased release of cyclic adenosine monophosphate into jugular vein in response to isoproterenol administration.

Catecholamine administration elevates plasma cyclic AMP (cAMP) levels but the source of the cAMP is unknown. To determine possible sources, plasma cAMP levels were determined in blood vessels across the head, liver, kidney and lung in anesthetized dogs infused with the beta-adrenergic agonist, isoproterenol. Only the head showed an increased release of cAMP into the blood. The kidneys removed cAMP from the blood while liver and lung showed no change. This in vivo demonstration of release of cAMP from the head represents contributions from brain and facial muscles and may be a useful approach to study brain involvement in the action of various hormones and drugs.

Preservation of myocardial ATP during cardioplegia: comparison of techniques.

Preservation of myocardial ATP enhances the heart's ability to resume normal function following aortic crossclamping (AXC). Preservation of this high energy substrate during 4 cardioplegia delivery techniques was evaluated and compared with changes occurring during 4 hours of continuous coronary perfusion. Dogs (31) were placed on cardiopulmonary bypass and transmural left ventricular biopsies obtained for control ATP measurements. Animals were then divided into five groups: Group I (n = 6): 4 hrs. of continuous coronary perfusion (CCP); Group II (n = 6): 3 hrs. continuous AXC, multidose blood cardioplegia (MBC); Group III (n = 6): 3 hrs. continuous AXC, multidose crystalloid cardioplegia (MCC); Group IV (n = 6): 2 hrs. intermittent AXC, single dose BC (SBC); Group V (n = 7): 2 hrs. continuous AXC, continuous perfusion BC (CBC). In each group, where applicable, myocardial biopsies were taken at 30 minute intervals during AXC, before and after cardioplegia injection, and 30 minutes following final unclamping and rewarming. Hearts in Group II (MBC) and V (CBC) showed greatest preservation of ATP stores (increases 1.1 +/- 1.2%, increases 1.8 +/- 0.9% respectively; p greater than .05) ATP levels rose as high as 23 +/- 2% (p less than .005) above control immediately following cardioplegia injection in Group II (MBC). Group IV showed poorest preservation of ATP (decreases 26 +/- 5%, p less than .01) with levels falling as much as 37 +/- 10% (p less than .01) during the period of AXC. Hearts in Group I (CCP) demonstrated a 15.6 +/- 7.5% decrease in ATP from control (p less than .05). Group III (MCC) also showed a steady decline in ATP declining 18 +/- 3% (p less than .005) from control. These data indicate that multidose blood and continuous-blood cardioplegia techniques will maintain normal myocardial ATP stores throughout the period of AXC. These groups actually show a slight rise in ATP as compared to 4 hrs. of continuous coronary perfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

A simplified method for delivery of cold blood cardioplegia and aortic root venting during coronary artery bypass.

We present a simplified method for delivery of cold blood cardioplegia and left ventricular decompression during coronary artery bypass surgery when aortic occlusion is utilized. The system provides immediate delivery of the cardioplegic solution followed by continuous sump suction on the aortic root to decompress the left ventricle and to aspirate non-coronary collateral flow. This system has been utilized in over 200 consecutive cases of coronary revascularization without complication and is a safe, effective and inexpensive method of both delivery of the cardioplegic agent and maintenance of a dry quiet operative field.

An on-line system for delivery of blood cardioplegia.

A simplified system for delivery of cold blood potassium cardioplegia was tested in 12 experimental animals subjected to 180 minutes of aortic cross-clamping. This on-line system utilized blood drawn from the pump oxygenator which was volumetrically combined with a pre-mixed electrolyte solution (9 parts blood: 1 part drug). A separate heat exchanger was employed to deliver the cardioplegic infusate at 10-15 degrees C. Use of this system permits accurate regulation of infusate potassium concentration, pH, injection pressure and flow rate. Less than one minute is required to obtain an unlimited quantity of arrest solution at steady state values for these parameters. The efficacy of this method of delivery of blood cardioplegia was verified by biochemical and functional studies which revealed no significant changes in myocardial ATP, ultrastructure, compliance, or ventricular function after 3 hours of crossclamping. It is concluded that this system offers a safe and more simplified method of delivering blood cardioplegia than heretofore available.

Release of particulate matter from extracorporeal tubing: ineffectiveness of standard arterial line filters during bypass.

Microemboli resulting from extracorporeal circulation have been considered to be a cause of organ dysfunction after cardiopulmonary bypass. A scanning electron microscopic study was carried out to quantitate the number of nonbiological particles which escape capture by the arterial line filter in a standard extracorporeal circulation circuit. Five different lots of polyvinylchloride (PVC) tubing from the same manufacturer were used in closed circuit extracorporeal pump set-ups consisting of a typical length of PVC tubing, a cardiotomy reservoir, and an arterial line filter (Pall 40 microns (mu)). A liter of Plasmalyte was circulated through this set-up for 15 minutes at 2 liters/minute with the pump head set at almost total occlusion. The circulated Plasmalyte from each pump line was then collected and passed through a 0.22 mu Millipore filter. Numerous particles ranging from 5-40 mu in diameter were observed on the surface of the filters. A mean of 51.2 particles/mm2 of filter was found after the first recirculation period. By extrapolation the mean total number of particles contained in the Plasmalyte was calculated to be 70,943. A second similar 15 minute rinse on the same pump set-ups revealed the release of a mean of 51.0 particles/mm2, or a mean total number of 70,665 particles. Analysis of variance showed no significant difference in the number of particles produced by the first compared with the second recirculation period but there were significant differences (P less than .05) between the numbers of particles produced by the different lots of tubing. This study demonstrates that commonly employed tubing packs and standard roller pump designs for extracorporeal circulation are associated with continuous release of particulate matter (5-40 mu) which is not removed by the arterial line filters most often employed. These particles seem to be released at a constant rate which makes an initial pre-bypass filtration run ineffective. Such particles can only be removed by continuous use of lower porosity filters in the pump circuit. The clinical significance of these large numbers of small particles is unknown, but they may contribute to the multi-organ failure often seen in prolonged (greater than 2 hour) periods of cardiopulmonary bypass.

Variations in total and ionized calcium during cardiac surgery.

Twenty patients undergoing cardiac surgery were studied to examine variations in total and ionized serum calcium and urine calcium during cardiopulmonary bypass. Serial samples of blood and urine were analyzed during bypass using a highly specific calcium electrode to determine the effects of hemodilution, various pharmacologic agents, and transfusions of citrated blood. Calcium chloride was routinely added to the crystalloid pump prime (400 mgs/L) and also administered when additional blood or crystalloid were infused. An average of 4.8 +/- .50 grams of calcium chloride was given per procedure. After induction of general anesthesia with nitrous oxide and Halothane, total serum calcium decreased from 10.0 +/- 0.3 to 8.5 +/- 0.8 mg% (p less than 0.05). Following heparinization, ionized calcium decreased from 4.2 +/- .08 to 3.9 +/- 12 mg% (p less than 0.05). Ionized calcium was not affected by reversal of heparin with Protamine. Following institution of cardiopulmonary bypass the ratio of ionized to total calcium declined about 13.4% (0.49 vs. 0.43). This ratio did not change during bypass but returned to normal immediately post-perfusion. Urinary calcium excretion averaged 1.9 +/- 0.6 mg/min and could not be implicated as a cause of hypocalcemia during bypass. Post-perfusion, ionized serum calcium rose 1.3 +/- .01 mg% for each gram of exogenously administered calcium chloride (p less than 0.05). From these observations, we conclude: (1) ionized and total serum calcium levels decreased significantly following institution of cardiopulmonary bypass alone, presumably as a result of hemodilution from the crystalloid pump prime and addition of citrated blood products; (2) induction of general anesthesia alone with nitrous oxide and Halothane is associated with a significant decrease in total serum calcium; (3) ionized calcium declined following heparinization but is unchanged by Protamine administration; (4) changes in total and ionized serum calcium are unaffected by urinary excretion during bypass; (5) exogenously administered calcium chloride significantly increases serum ionized calcium and these changes are inversely related to the circulating pool of calcium; (6) current protocols for administration of exogenous calcium chloride during bypass may result in insufficient levels of ionized calcium and we have adopted measures to correct these deficiencies, when indicated.