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Isradipine has been shown to be an effective vasodilator in different vascular beds. Experimental evidence suggests that isradipine is a potent coronary vasodilator, and this is supported by clinical studies in both cardiology and cardiac surgery. Furthermore, in these studies, coronary vasodilation was not accompanied by evidence of any significant effect on cardiac contractility or conduction. It can be concluded that the cardiac effects of isradipine will ultimately prove to be beneficial in patients undergoing myocardial revascularization.

The effects of isradipine (ISR) on cardiac performance, myocardial metabolism, and coronary blood flow were compared with those of sodium nitroprusside (SNP) when used to control blood pressure following myocardial revascularization. Twenty patients were randomized to receive either intravenous ISR or SNP if arterial blood pressure increased above 130 mm Hg systolic. Hemodynamic and metabolic parameters were studied using radial, pulmonary arterial, and coronary sinus catheters. Cardiac output and coronary blood flows were measured by thermodilution and blood was taken for calculation of myocardial oxygen consumption and lactate extraction. Electrocardiographic changes were recorded by Holter monitoring throughout the study. ISR and SNP both produced a satisfactory reduction in blood pressure accompanied by a decreased systemic vascular resistance (P less than 0.001). ISR infusion was associated with increases in cardiac output and stroke index (P less than 0.01), which were not apparent in the SNP group. Tachycardia occurred with SNP (P less than 0.01) but not with ISR therapy. Right and left ventricular stroke work indices and myocardial oxygen consumption were reduced with SNP. The ISR group showed unchanged myocardial oxygen consumption with increased right ventricular stroke work index. Coronary vascular resistance decreased (P less than 0.01) during ISR infusion but decreased only slightly in the SNP group. Great cardiac vein blood flow was significantly increased with ISR but not with SNP, resulting in a significant difference between the groups (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

The haemodynamic, cardiac metabolic and electrocardiographic effects of the intravenous inotropic agent DPI 201-106, in 20 and 40 milligram doses, were studied in patients after coronary arterial bypass grafting. The patients were randomly allocated to receive placebo or DPI 201-106. Those receiving the active drug received either the 20 or the 40 milligram dosages of DPI 201-106. Both the placebo and the active drug were infused over 20 minute periods. Two baseline readings confirmed haemodynamic stability, and readings were taken immediately following the infusions and then at 20 minutes and at 40 minutes afterwards. Comparison of all the haemodynamic and metabolic data did not reveal any significant intra or inter group differences. Comparison of the electrocardiographic data revealed some differences. Patients receiving DPI 201-106 showed prolongation of the QTc interval immediately following the infusions. Changes in ST segments and T waves were observed. Independent analysis of the affected electrocardiographs reported that the changes were suggestive of, but not pathognomonic of, myocardial ischaemia. The metabolic data showed that the electrocardiographic changes were not associated with any evidence of anaerobic metabolism. The indication for DPI 201-106 as a positive inotropic agent in patients following coronary revascularization surgery was not established.

Diffuse impairment of ventricular function after cardiac surgery may be related to the generation during reperfusion of the myocardium of free radicals derived from oxygen. Fifteen patients undergoing elective coronary bypass surgery were studied by previously described assays for peroxidised lipids and for isomerised lipids which were used as indices of free radical activity. Serial blood samples were obtained from systemic arterial, mixed venous, and coronary sinus catheters before, during, and after the ischaemic period. The patients underwent coronary artery surgery on cardiopulmonary bypass with a membrane oxygenator, relative hypothermia 30-34 degrees C, and intermittent cross-clamping of the aorta. During the ischaemic periods there were no significant changes in the indices of free radical activity. During the reperfusion phase there was a significant increase in free radical indices in arterial and mixed venous blood. A small rise in free radical indices in coronary venous blood was not statistically significant. These data indicate that free radical activity is increased in patients shortly after the cessation of cardiopulmonary bypass. The pattern of distribution between the different sampling sites suggests that much of the observed increase in isomerised and peroxidised lipids originates from tissues other than the myocardium.

Bacterial endocarditis is a complex disease associated with high morbidity and mortality with complications that include acute heart failure and arterial embolism. Venous thrombosis of the lower limbs is not uncommon following all forms of surgery, but infrequent following cardiac surgery, and rarely progresses to venous gangrene. We report a case of bilateral lower-limb venous gangrene, in a 49-year-old female who underwent aortic valve replacement for native valve endocarditis. The possible aetiology of this complication is discussed.

Objective: To analyze the relationship among Holter electrocardiogram (ECG) recordings, hemodynamic measurements indicative of global myocardial oxygen balance, and serum cardiac troponin I concentrations (cTnl) in the early postoperative period after coronary artery bypass graft (CABG) surgery. Design: Prospective observational study. Setting: University teaching hospital. Participants: Thirty patients undergoing CABG surgery. Interventions: ECG measurements consisted of Holter and standard ECG recordings. Hemodynamic measurements included heart rate, systolic and diastolic blood pressure (SBP, DBP), pulmonary capillary wedge pressure, and cardiac index (CI). Derived indices included tension time index (TTI), rate-pressure product, pressure work index (PWI), and endocardial viability ratio (EVR). Serial measurements of cTnl concentrations were measured postoperatively; the area under the cTnl concentration time curve was calculated for each patient (AUC cTnl). Measurements and Main Results: Episodes of myocardial ischemia were associated with small but significant rises in SBP (p = 0.01), DBP (p = 0.001), and TTI (p = 0.005) compared with periods without ischemia in the same patients. Serum cTnl concentrations 24 hours after cardiopulmonary bypass (p = 0.03) and AUCcTnl (p = 0.01) values were greater in patients who developed ECG myocardial ischemia compared with patients who did not. Conclusions: The small changes in hemodynamics seen, although statistically significant, are unlikely to be the primary cause of the ischemia. They more likely reflect an independent process that causes or occurs as a result of ischemic episodes. Ischemic episodes detected by the Holter monitor are associated with significant release of cardiac troponin from the myocardium.

Objective: This study was designed to evaluate objectively the incidence of Helicobacter pylori infection and upper gastrointestinal (GI) bleeding in patients following heart valve replacement surgery. Since the discovery of Helicobacter pylori, its association with gastritis, peptic ulceration and upper GI bleed have been extensively studied. Anticoagulation of patients with mechanical heart valve prostheses is a prerequisite for the prevention of valve thrombosis and thrombo-embolic events. However anticoagulation can have its complications, notably that of upper GI bleeding. Methods: Patients were assessed in routine postoperative outpatient clinics following cardiac valve replacement surgery. This assessment comprised initially of a questionnaire reflecting the symptomatology of upper GI bleeding and its subsequent management. With informed consent, a small sample of blood was obtained by stilette. The Helicobacter pylori status was assessed by measuring the presence of antibodies (immunoglobins) to Helicobacter pylori in a commercially available test kit, the Rapid Helisal Test. In this preliminary study 150 consecutive patients were scrutinised and their responses to the questionnaire were collected and compared with the Helisal test. Results: From the 150 patients studied, 37 patients were found to be positive to the Helisal test for Helicobacter pylori infection, representing 24.6% of all the cohorts. Of these 37 patients, eight gave a positive history of upper GI bleed; five requiring hospital admission with three requiring urgent upper GI endoscopy. Although these eight patients represent only 4.4% of the total group, it is significant to note that this represents 21.6% of those patients found to be Helicobacter pylori positive. There were no GI complications in any of those tested negative. There was an increasing incidence of Helicobacter pylori infection in the older age group of patients. Conclusions: Helicobacter pylori infection is a common infection with serious consequences in heart valve surgery. For those requiring anticoagulation, the incidence of serious consequential upper GI bleed is significantly higher in the presence of this infection. Preoperative or immediate postoperative eradication of the organism is mandatory in those patients requiring indefinite anticoagulation.

A prospective trial to compare the effects of the synthetic dopaminergic (DA1) agonist, fenoldopam (FEN), with sodium nitroprusside (SNP) for control of blood pressure following coronary artery bypass graft surgery was carried out in 20 patients. Patients were randomly allocated to receive either FEN or SNP when the systolic arterial blood pressure (SAP) rose above 130 mmHg. The goal of therapy was to achieve a stable control of blood pressure below 130 mmHg at a level at least 25 mmHg below the pretreatment value. Treatment was then continued for 2 hours. Hemodynamic measurements were made before treatment, after stable control of blood pressure had been achieved, and thereafter at 30, 60, and 120 minutes. Urine output, sodium, potassium, and creatinine clearance were also measured during the study. Both SNP and FEN caused a rapid and significant fall in SAP (P < 0.001) and a fall in systemic vascular resistance (P < 0.001). FEN caused an increase in cardiac index (P < 0.001) and in stroke volume (P < 0.001) in contrast to SNP. Urine output and potassium clearance fell with SNP (P < 0.05) in contrast to FEN. Thus, FEN would appear to control SAP as effectively as SNP, but may have more beneficial effects on cardiac output and some aspects of renal function.

Changes in the electrophoretic mobility of mammalian cells following irradiation with X, δ and β rays are reported. The cells investigated were human and cockerel erythrocytes and Ehrlich Ascites Tumour Cells. The electrophoretic mobility of the cells showed a biphasic response with dose. The general trend of the response was that the cockerel erythrocytes showed an initial increase in mobility, then a return to normal levels. Human erythrocytes and ascites cells exhibited an initial decrease in mobility before returning to the control values. The X and δ dose levels required for these changes were similar and substantially greater than when β radiations were used.

Nutritional studies were carried out on 47 randomly selected patients undergoing valve replacement. The total-body potassium was measured noninvasively, by use of a whole-body monitor with an accuracy of ±4 percent. This was used as an absolute index of nutritional status of the nonacidotic patient. The metabolic response to operation, as calculated from changes in total-body potassium, was a median loss of 11.1 Gm. or a mean loss of 9.8 Gm. of nitrogen per day over 7 postoperative days, compared with a mean loss of 6.8 Gm. of nitrogen per day in the same patients as calculated by conventional nitrogen balance methods. Total-body water measured before operation was not significantly different from the predicted level (p > 0.05), and there was no difference between preoperative total-body water and that measured on the seventh postoperative day (p > 0.07). Twenty-three of the patients exhibited preoperative nutritional depletion (range, 5 to 30 percent) as assessed by loss of body cell mass from total-body potassium measurements. The well-nourished patients had a median postoperative hospital stay of 17 days (range, 11 to 25) compared with 27 days (range, 12 to 60) for those who had been nutritionally depleted (p

A study was undertaken to assess the use of intravenous nifedipine in controlling hypertension in patients following coronary artery surgery. A combined hemodynamic and metabolic assessment was carried out in 15 patients on data recorded at six sequential time intervals: (1) baseline, (2) control of blood pressure, (3) 30 minutes after control of blood pressure, (4) 1.5 hours after control of blood pressure, (5) 3.5 hours after control of blood pressure, and (6) 30 minutes after discontinuing nifedipine. Coronary sinus and great cardiac vein blood flows were measured by the continuous thermodilution technique using the Baim coronary sinus flow catheter. Intravenous nifedipine was run initially at an average rate of 1.82 microg/kg/min. It took an average time of 12 minutes to lower the blood pressure to less than 130 mmHg systolic. There were highly significant decreases in systolic, mean, and diastolic blood pressures (P < .001), associated with significant decreases in systemic vascular resistance (P < .001) and left ventricular stroke work index (P < .05). There was an increase in cardiac output at 30 and 90 minutes of infusion (P < .05), and the stroke volume was increased 90 minutes after starting nifedipine (P < .05). The increase in heart rate was not significant. There was no significant effect on conduction times as measured by PR and QRS intervals on the ECG. However, the QTc interval was decreased after 3.5 hours (P < .05). There was an increase in right atrial pressure at 90 minutes and again 30 minutes after stopping nifedipine. (P < .05). The pulmonary artery pressure also was increased after stopping the infusion (P < .05). The pulmonary capillary wedge pressure, pulmonary vascular resistance, and right ventricular stroke work index remained unchanged. Coronary sinus and great cardiac vein flows were maintained despite a decrease in perfusion pressure, suggesting that nifedipine is a potent coronary vasodilator. Indeed, coronary vascular resistance was significantly decreased (P < .05). Myocardial oxygen consumption remained unchanged. The lactate extraction indicated that myocardial metabolism remained aerobic regionally and globally. Thus, the results suggest that blood pressure was easy to control and that there were no adverse effects on atrioventricular conduction, cardiac performance, regional and global myocardial oxygen utilization, or lactate extraction.

Myocardial ischemia before and during coronary artery surgery is significant, because patients who develop perioperative myocardial ischemia have an increased incidence of postoperative myocardial infarctions. Thus, the prevention of ischemic episodes is of great importance. This study was undertaken to (1) compare the effects of intravenous nitroglycerin (NTG) with isosorbide dinitrate (ISDN); (2) investigate if the continuous infusion of nitrates had beneficial effects on cardiac performance and metabolism; and (3) compare the control of blood pressure with the nitrates versus halothane during a standardized anesthetic. Twenty-one patients participated in the study, and all had the following: a radial arterial catheter, peripheral venous catheter, 7F pulmonary artery catheter, and Baim coronary sinus flow catheter. The study was carried out in the prebypass period beginning with awake measurements of baseline parameters, and ending after median sternotomy. The patients were divided into three groups: group 1 received an infusion of NTG; group 2 received an infusion of ISDN; and group 3, the control, received neither nitrate, but halothane was added to control hemodynamics. Measurements were made at the following time intervals: (1) baseline; (2) after 5 minutes of the nitrate infusions while awake (groups 1 and 2); (3) after induction of anesthesia, laryngoscopy, and intubation; and (4) after median sternotomy. In groups 1 and 2, the nitrates were infused at 0.1 mg/kg/h for 5 minutes. Thereafter, blood pressure control and treatment of episodic hypertension were achieved by alteration of the rate of nitrate infusions, or, in group 3, by 0.5% to 2% of inspired halothane.(ABSTRACT TRUNCATED AT 250 WORDS)

A dose-finding pilot study including six patients concluded that isradipine at an initial rate of 0.6 microgram/kg/minute, decreasing to 0.3 microgram/kg/minute with further adjustments as necessary, was safe for the treatment of post-aortocoronary bypass graft hypertension. A comparative study followed, comprising 20 patients randomly assigned to receive isradipine (starting at 0.6 microgram/kg/minute) or nitroprusside (initially 1 microgram/kg/minute) for the treatment of post-aortocoronary bypass graft hypertension. Both drugs produced a satisfactory reduction in arterial blood pressure accompanied by a decrease in systemic vascular resistance. Central venous pressure and mean pulmonary artery pressure decreased with nitroprusside, but both increased with isradipine. Pulmonary capillary wedge pressure was reduced, heart rate increased, and cardiac output was minimally changed with nitroprusside. However, wedge pressure was maintained with isradipine and there was no tachycardia. An increase in cardiac output was seen, associated with an increase in stroke index. Isradipine is a more specific treatment for post-aortocoronary bypass graft hypertension than nitroprusside because its systemic arterial dilating effect is associated with a minimum of other circulatory changes.

In order to reduce the high rate of inoperability in patients with bronchial carcinoma, mediastinoscopy was carried out as a routine preoperative selection in 874 patients during 13 years. Two hundred thirty-six patients (27%) were found to have involved lymph nodes at mediastinoscopy and were not treated surgically. Follow-up data were available on 210 of them: 165 (79%) died within a year, 16 survived for 2 years, and 4 for 5 years. Pulmonary resection was carried out in 638 patients. Five-year survival in the series was 24.5% and 10-year survival (based on 104 eligible patients), 16.3%, including the operative mortality of 5.5%. Mediastinoscopy has not improved long-term survival to any great extent. However, it has raised the rate of resectability to 97.1% and lowered the operative mortality without denying the patient a chance of cure.

Summary A case is described in which Nocardia asteroides caused mediastinal suppuration leading to superior and inferior vena caval obstruction with subsequent metastatic cervical osteomtelitis. The surgical and antibiotic management is discussed.

In 10 patients undergoing heart-valve replacement with cardiopulmonary bypass total-body potassium was measured non-invasively with a whole-body monitor, and this measurement was used to derive the lean body mass as an index of the nutritional status. From measurements made before operation and on the 7th postoperative day, the metabolic response to surgery was found to be equivalent to a negative nitrogen balance of 10.8 g of nitrogen a day (50% greater than that calculated from conventional nitrogen-balance studies). 4 patients had a mean preoperative potassium depletion of 17.2%, and this was associated with increased morbidity. Well-nourished patients had a mean postoperative hospital stay of 16 days, whereas those in a depleted state before operation had an increased morbidity, as measured by their mean postoperative stay of 30 days. More attention needs to be given to the preoperative nutritional status of patients undergoing heart-valve replacement.