Baikunth Bharadwaj

Increased oxygen free radical activity in patients on cardiopulmonary bypass undergoing aortocoronary bypass surgery

Cardiac dysfunction after cardiopulmonary bypass (CPB) has been reported by various investigators. Oxygen free radicals have been shown to depress cardiac function and contractility. To evaluate the possible role of oxygen free radicals (OFR) in post-pump cardiac dysfunction, measurements of cardiac function, OFR producing activity of polymorphonuclear (PMN) leukocytes (PMN chemiluminescence) and malondialdehyde (MDA), a lipid peroxidation product, in blood were made at induction of anesthesia (T1), before cross clamping of the aorta (T2), after closure of the chest (T3), and 24 hours postoperatively (T4) in 21 patients undergoing aortocoronary bypass surgery. The total OFR-derived chemiluminescence at T1, T2, T3, and T4 was 1590 +/- 156, 3169 +/- 338, 1972 +/- 214, and 2614 +/- 366 mv.min.10(6) PMN-1, respectively. Superoxide dismutase (SOD)-inhibitable chemiluminescence at T1, T2, T3, and T4 was 1214 +/- 129, 2674 +/- 328, 1752 +/- 215, and 2139 +/- 292 mv.min.10(6) PMN-1, respectively. Superoxide anion at T1, T2, T3, and T4 was 0.99 +/- 0.14, 1.30 +/- 0.17, 1.07 +/- 0.14, and 1.19 +/- 0.12 nmol.10(6) PMN-1.30 min-1, respectively. Blood MDA at T1, T2, T3, and T4 was 0.17 +/- 0.02, 0.25 +/- 0.03, 0.20 +/- 0.03, and 0.23 +/- 0.02 nmol/ml, respectively. OFR-derived and SOD inhibitable chemiluminescence, superoxide anion, and blood MDA increased significantly during CPB and postoperatively. There were decreases in the blood pressure and stroke volume, and increases in the central venous pressure, capillary wedge pressure, and heart rate during CPB and postoperatively. Cardiac output remained unchanged during this procedure. There was leukopenia during CPB.(ABSTRACT TRUNCATED AT 250 WORDS)

Oxygen free radicals in volume overload heart failure

It has been suggested that oxygen free radicals (OFR) depress the excitation-contraction coupling in cardiac muscle. It is possible that a decrease in the cardiac contractility in the failing heart may be due to an increased OFR producing activity of polymorphonuclear (PMN) leukocytes. We studied the OFR producing activity (chemiluminescence) of PMN leukocytes from blood in dogs with heart failure due to chronic volume overload. The animals were divided into two groups: I) normal, (n = 10): II) dogs with mitral insufficiency (MI) of 6 to 9 months duration, (n = 10). Hemodynamic studies were done to establish the presence of heart failure. Blood samples were collected to measure PMN leukocyte chemiluminescence. There was a decrease in the cardiac index and index of myocardial contractility (dp/dt/IIP) and an increase in the left ventricular end-diastolic pressure in dogs with MI indicating left ventricular failure. The peak chemiluminescent activity of the PMN leukocytes in blood of dogs with failure was about four folds greater than that in the blood from normal dogs. These results suggest that there may be an increased OFR generation in dogs with volume overload heart failure. The decrease in the myocardial contractility in the failing heart might be due to an increase in the OFR produced by the PMN leukocytes.

Right Atrial Myxoma Presenting as Budd-Chiari Syndrome

A 25-year-old man experienced rapidly progressing Budd-Chiari syndrome. Despite extensive radiological investigations, no atrial mass could be identified. At operation, a right atrial myxoma was found that originated from the eustachian valve and prolapsed into the inferior vena cava. Following successful removal of the myxoma, the ascites and peripheral edema resolved completely. Right atrial myxoma is a rare cardiac tumor that may present with embolic, obstructive, or constitutional signs and symptoms and is a potentially curable cause of Budd-Chiari syndrome.

Effects of Blood and Crystalloid Cardioplegia on Cardiac Function at Organ and Cellular Levels During Hypothermic Cardiac Arrest

The present investigation was undertaken to compare the effects of cold crystalloid and blood cardioplegia on the functional recovery of the heart; on Ca+ + binding and uptake, Ca+ + -ATPase of the sarcoplasmic reticulum (SR), and sarcolemmal (SL) ATPase; and on serum MB fraction of creatine kinase (MBCK) after one and a half hours of reperfusion following one hour of ischemic cardiac arrest in dog. This study was made also to determine if the functional changes are related to the changes in biochemistry at the molecular level. The dogs were divided into three groups: sham bypass (SB), cold crystalloid cardioplegia (CC), and pump blood cardioplegia (PB). There was a decrease in the cardiac index (CI), left ventricular work index (LVWI), and mean aortic pressure (MAP) in all three groups. The index of myocardial contractility ((dp/dt)/IIP) and CI were lower in the CC group as compared with the SB and PB groups. All the hemodynamic values for the PB group were similar to those of the SB group except total systemic vascular resistance (TSVR) and left ventricular end-diastolic pressure (LVEDP) which were lower in the PB group. The index of myocardial contractility and cardiac index appeared to be greater in the PB group than in the CC group. There was a decrease in the Ca ++ uptake by SR from both the CC and PB groups. Ca++ binding and Ca++ -ATPase of SR from the PB group were depressed. The sarcolemmal ATPase was unaffected in both groups. The serum MBCK increased in both PB and CC groups, though the increase was smaller in the PB group. These results indicate that the functional recovery of the heart was slightly better with pump blood cardioplegia than with cold crystalloid cardioplegia. The depressed myocardial contractility and cardiac function in the CC group were associated with a decrease in the Ca+ + uptake by SR. However, the decreases in the Ca+ + binding, Ca+ + uptake, and Ca+ + ATPase by SR from the pump blood cardioplegic group were not accompanied by decreases in the cardiac contractility and cardiac function. Myocardial damage as assessed by serum MBCK was smaller in the PB group than in the CC group.

Mitral valve replacement in the neonate: A report of two cases

SummaryMitral valve replacement was performed in two critically ill neonates with severe mitral stenosis and regurgitation. Both patients had coexisting severe aortic stenosis previously treated by transventricular aortic valve dilatation.Preoperative echocardiography showed a mitral annulus measuring between 11 and 12 mm in diameter—too small for any of the commercially available free-standing valve prostheses. Accordingly, the porcine valve from a commercially available 12-mm external-valved conduit was removed and sutured into position. The function of the valve was satisfactory in both cases and cardiopulmonary bypass was discontinued easily with a good cardiac output established in both.Both patients died—one at 20 h and one 36 h after surgery. In each case, the immediate cause of death was acute bleeding secondary to preexisting hepatic failure and depletion of coagulation factors.At autopsy, both prostheses had been correctly placed and were competent. Left ventricular outflow tract obstruction secondary to strut imposition was not evident.Both patients were very ill preoperatively. Although neither patient survived mitral valve replacement, we were encouraged by the relative hemodynamic improvement in the immediate postoperative period. We believe that prosthetic valve replacement could become a viable therapy for the neonate with severe mitral valve abnormalities.

The Fate of Autologous Fascia Lata Grafts in Dogs

The fate of tricuspid fascia lata valves and intracardiac grafts was studied morphologically, histologically, and biochemically in dogs. Severe degenerative changes occurring by 21 days were largely correlated with graft thickening due to gross endothelialization. A primary event in graft alteration was an initial loss of the indigenous fibroblast population as detected both microscopically and by autoradiography after pulse labeling with 14C-Nethylmaleimide. Using different isotopic labeling procedures, both the in vivo and in vitro graft degradation patterns demonstrated that a second early eft degradation was correlated in vivo with endothelialization and collagenase secretion by invasive cells.

Effects of Diltiazem on the Functional Recovery of the Myocardium at Organ and Cellular Level During Prolonged Hypothermic Ischemic Cardiac Arrest

The effectiveness of diltiazem on the functional recovery of the heart, cal cium (Ca++) uptake and binding, Ca++ ATPase of cardiac sarcoplasmic reticu lum (SR), and MB fraction of creatine kinase (MBCK) of coronary sinus blood was investigated after one and a half hours of reperfusion following three hours of ischemic cardiac arrest. The dogs were divided into three groups: group I, sham bypass; group II, cold crystalloid cardioplegia; and group III, cold crys talloid cardioplegia with diltiazem. There was a decrease in aortic pressures left ventricular pressure development (dp/dt), left ventricular work index (LVWI), total systemic vascular resistance (TSVR), and left ventricular systolic pressure (LVSP) in the sham bypass group. There was a decrease in cardiac index (CI), LVWI, and mean right atrial pressure (mRAP) and an increase in TSVR and pulmonary vascular resistance (PVR) in group II as compared with group I. Although there was a tendency for a decrease in the indices of myocardial con tractility in group II, they were not significantly different from those in group I. The indices of myocardial contractility, CI, and LVWI in group III were slightly higher than in group II, but they were not significantly different from each other. The values for calcium uptake by SR in groups II and III were similar but significantly lower than those in group I. Calcium binding in group III was significantly lower than that in group I. Calcium ATPase of SR in the three groups were similar. Although MBCK increased in all the groups, the increases were not significantly different among the three groups. The results of this study indicate that cold crystalloid cardioplegia with diltiazem was not better than cold crystalloid alone in preserving the cardiac contractility and cellular function during prolonged ischemic cardiac arrest. However, the cardiac func tion in terms of cardiac index was better preserved with diltiazem.

Complex transposition with interrupted right aortic arch and partial Di George syndrome: Successful palliation with combined medical and surgical therapy

SummaryA five-day-old infant with transposition of the great arteries, ventricular septal defect, and an interrupted right aortic arch underwent successful balloon septostomy, pulmonary artery banding, and aortic arch repair. The infant also had abnormal facies with severe refractory hypocalcemia and depressed T-lymphocyte number and function believed to represent a partial Di George syndrome. The hypocalcemia resolved following treatment with a vitamin-D analogue, T-cell number increased, and T-cell function improved, but both remained subnormal.

High 2,3-DPG blood cardioplegia and myocardial preservation during cardiopulmonary bypass.

Blood may provide superior cardioplegia compared with crystalloid cardio plegic solution. However, the results are controversial. This may be due to a leftward shift of the hemoglobin (Hb)-02 dissociation curve induced by hypo thermia, increasing the oxygen affinity for Hb. This effect may negate the po tential benefit of blood cardioplegia. The oxygen affinity for Hb can be decreased by increasing the red cell 2,3-diphosphoglycerate (2,3-DPG), and hence, more oxygen can be delivered to the myocardium. The present investiga tion was undertaken to study the effects of 2,3-DPG-enriched blood cardiople gia on the functional recovery of the myocardium and changes in the coronary sinus red blood cell (RBC) adenosine-triphosphate (ATP), lactate, and RBC DPG after one and a half hours of reperfusion following one hour of ischemic cardiac arrest in dogs. The dogs were divided into three groups: crystalloid (CR); stored blood (SB), and high 2,3-DPG blood (HDPG) cardioplegic groups. Incubation of canine RBC in phosphoenal pyruvate (PEP) led to a 36% increase in DPG and a rightward shift in the Hb-O2 dissociation curve. There was a 4 mm Hg shift in the P50. When compared with the CR group, there was a significant decrease in the cardiac index (CI) and left ventricular work index (LVWI) and a significant increase in the total systemic vascular resistance (TSVR) in the SB group. The CI and LVWI of the HDPG group were similar to those of the CR group, but the TSVR was significantly greater in the former group. The LVWI was significantly greater and the TSVR smaller in the HDPG group as com pared with those in the SB group. The coronary sinus, lactate, and RBC 2,3- DPG were never significantly different at any point among the three groups, although a trend toward a decrease in lactate with the HDPG group was ob served. There was no significant difference in the RBC ATP content from the three different groups except during initial period of ischemic arrest when RBC ATP content of HDPG group was greater than that in CR group. There was a decrease in the Hb content of the blood in all three groups. The decreases were similar in all the groups except during the postpump period, when the Hb con tent of the HDPG and SB groups was higher than that of the CR group. These results suggest that stored blood was inferior to crystalloid and HDPG cardioplegia in preserving the myocardial function and cardiac metabolism. However, HDPG cardioplegia was not better than CR cardioplegia in preserv ing the cardiac function. Better preservation of cardiac function with HDPG as compared with the SB group might be due to a rightward shift in the Hb-O2 dissociation curve.

Saccular aortic aneurysm in an asymptomatic child

SummaryAn asymptomatic boy was found to have coarctation of the thoracic aorta. Despite no history of endocarditis or trauma, a large saccular aneurysm involving the coarctation site was identified angiographically, confirmed, resected surgically, and examined histologically.