Rajendar Krishan Suri

The effect of magnesium sulphate on hemodynamics and its efficacy in attenuating the response to Endotracheal intubation in patients with coronary artery disease

Laryngoscopy and endotracheal intubation may produce adverse hemodynamic effects.Magnesium has direct vasodilating properties on coronary arteries and inhibits catecholamine release, thus attenuating the hemodynamic effects during endotracheal intubation. We studied 36 patients with coronary artery disease (CAD) scheduled for elective coronary artery bypass grafting to evaluate the hemodynamic effects of magnesium and its efficacy in attenuating the response to endotracheal intubation. Patients received either 0.1 mL/kg (50%) magnesium sulfate (50 mg/kg) (Group A, n = 19) or isotonic sodium chloride solution (Group B, n = 17) before the induction of anesthesia and 0.05 mL/kg of isotonic sodium chloride solution (Group A) or lidocaine 2% (1 mg/kg) (Group B) before intubation. The hemodynamic variables were recorded before induction, after the trial drug, after induction, and after endotracheal intubation. Automatic ST segment analysis was performed throughout the study period. Magnesium sulfate administration was associated with increased cardiac index (P < 0.01), a minimal increase in heart rate, and a significant decrease in mean arterial pressure (MAP) and systemic vascular resistance (SVR) (P < 0.001). None of the patients in the magnesium group had significant ST depression compared with three patients in the control group. The magnesium group patients had a significantly lesser increase in MAP (P < 0.05) and SVR (P < 0.01) compared with the control group patients who received lidocaine before endotracheal intubation. Thus, magnesium is an useful adjuvant to attenuate endotracheal intubation response in patients with CAD. Implications: Endotracheal intubation produces adverse hemodynamic effects, which may be more detrimental in patients with coronary artery disease than in healthy patients. The present study shows that magnesium administered before endotracheal intubation can attenuate this response better than lidocaine. (Anesth Analg 1998;87:808-11)

Release of pro-inflammatory mediators during myocardial ischemia/reperfusion in coronary artery bypass graft surgery.

Inflammation has been reported to play an important role in cardiac surgery under cardiopulmonary bypass due to systemic endotoxemia. In order to develop strategies against this injury in future we studied the combined effect of a number of inflammatory mediators in myocardial ischemia/reperfusion. Coronary sinus blood samples of ten patients undergoing coronary artery bypass graft surgery (CABG) were obtained at three time intervals (1) before onset of bypass (2) 30 min after cross clamp, and (3) 10 min after removal of cross clamp. The samples were subjected to evaluate levels of nitric oxide byproducts (nitrite and nitrate and citrulline), inflammatory cytokines (interleukin-2, interferon-γ and interleukin-6), adhesion molecules, (CD62L and CD54), ratio of cell surface markers (CD4/CD8 and TCRαβ/γδ) cell activation markers (CD69 and HLA DR) and second messengers (protein kinase C, inositol 1,4,5 triphosphate and intracellular calcium levels). Ischemia and further reperfusion resulted in significant rise in nitrite and nitrate levels (p < 0.001), interleukin-6 (p < 0.01), CD62L (p < 0.001), CD69 (p < 0.05), protein kinase C (p < 0.001) and intracellular calcium (p < 0.001). A fall in CD4/CD8 ratio was observed on reperfusion. These changes during CABG show that ischemia/reperfusion leads to a release of an array of pro-inflammatory mediators of tissue injury, which could lead to pathophysiological changes. Hence the study suggests the need of some protective therapies against these inflammatory markers.

A possible role of HSP 70 in mediating cardioprotection in patients undergoing CABG

Heat shock protein 70 (HSP70) has been reported to be involved in myocardial self-preservation system. This study shows direct evidence of the effect of HSP70 on lymphocytes during ischemia and reperfusion in CABG (coronary artery bypass graft) surgery. Lymphocytes were separated from the blood obtained from 10 patients undergoing CABG at different time intervals. (i) Baseline samples (drawn before onset of bypass), (ii) ischemic samples (30 min after cross-clamp) and (iii) reperfusion samples (10 min after the cross clamp removal) were incubated with recombinant HSP70 and the cells were harvested after 36 h. The effect of HSP70 was monitored by measuring second messengers such as intracellular calcium, protein kinase C (PKC) and inositol tri phosphate (IP3). In addition CD69 expression was also measured. The results showed a significant decrease in intracellular calcium and CD69 expression in ischemia and further in reperfusion samples as compared to their respective un-triggered controls. PKC and IP3 levels however remained unaffected. The protective effect of HSP70 during ischemia and reperfusion could thus be attributed to decreasing intracellular calcium and CD69 expression. This study could therefore provide a mechanism of cardioprotection afforded by HSP70.

Role of Lymphocyte Subsets in Pathogenesis of Chronic Rheumatic Heart Disease

Analyses of lymphocyte subsets using flow cytometry were conducted to determine the significance of these cells in the pathogenesis of chronic rheumatic heart disease. Lymphocytes (B cells, T cells, CD4 cells, CD8 suppressor or cytotoxic T cells, activated T cells, and natural killer cells) were measured in blood and left atrial appendage samples of 30 patients with rheumatic heart disease and 10 patients with acyanotic congenital heart disease. Monoclonal fluorescent-labeled antibodies were used to identify various cells by flow cytometry. There was a significant increase in CD4 cells and activated T cells with a significant decrease in B cells in the left atrial appendage tissue of patients with rheumatic heart disease compared to those in the control group. There was no significant difference between the two groups in the distribution pattern of T lymphocytes in peripheral blood. These changes in rheumatic heart disease reflect an abnormal immunoregulatory mechanism with an ongoing enhanced immunological process continuing into the chronic phase of the disease. In our opinion, this persistent T cell response may lead to fresh damage to the myocardium and deformation of the heart valves.

Malignant Fibrous Histiocytoma of the Left Atrium

A 25-year-old female presented with symptoms resembling those of critical mitral stenosis. Echocardiography revealed a left atrial mass without a stalk, which was suspected to be a left atrial myxoma. An irregular soft friable mass was found at surgery. It measured 10 × 8 cm, with finger-like extensions and occupied almost the entire left atrial cavity, extending into the three tributaries of the right pulmonary vein. Histopathology of the excised tumor including electron microscopy showed a pleomorphic cytology interlaced with bundles, areas of necrosis, and occasional bizarre tumor giant cells. Characteristic histiocytes containing lysosomes identified the tumor as malignant fibrous histiocytoma. A postoperative course of radiotherapy with a dose of 4,000 cGy/20 fractions was applied to the mediastinum. At follow-up 4 months later the patient was asymptomatic. This case is reported because of the extreme rarity of left atrial malignant fibrous histiocytoma.

Recurrent left atrial myxoma presenting as peripheral arterial embolus

Recurrence of left atrial myxoma is rare. A male aged 18 years developed recurrence of left atrial myxoma despite excision of the tumour along with an ample cuff of the atrial septum around the tumour stalk, two years earlier. The patient presented with peripheral arterial embolus and underwent right femoropopliteal embolectomy and excision of the recurrent atrial myxoma. The presentation of recurrent left atrial myxoma with peripheral arterial embolism has perhaps not been reported earlier. Etiopathology of recurrence of myxomas and surgical treatment are discussed.

Post-Enteric Mycotic Aneurysm of Abdominal Aorta with Total Disruption

We report an extremely rare case of suprarenal mycotic aneurysm of the abdominal aorta below the origin of the superior mesenteric artery, secondary to Salmonella infection in a 3-year-old boy, which was associated with total disruption of the aortic wall. This case was successfully managed surgically with debridement and interposition of a double velour Dacron graft in the involved segment of aorta. A high degree of suspicion, angiographic evaluation supported by noninvasive investigations, and a planned surgical approach are required for a successful outcome.

Large Congenital Ventricular Septal Defect: Surgical Closure at Sixty Years

Large congenital ventricular septal defects have an unfavorable natural history and survival to 60 years of age with a large left-to-right shunt is very uncommon; surgical closure of such a defect in the elderly is even rarer. We report the case of a 60-year-old female who presented with a large left-to-right shunt across a congenital subaortic ventricular septal defect and underwent successful surgical closure.

Inferior Vena Caval Bullet Embolism

We report a case of bullet penetration into the left iliac vein, with embolus into the inferior vena cava and migration up to the junction of the inferior vena cava and the right atrium. The bullet was subsequently extracted through laparotomy from the infrarenal segment of the inferior vena cava, just above its bifurcation.

Cardiac Tumors: Surgical Experience in Thirty-Nine Cases

Over a period of 18 years, 39 cases of cardiac tumors were operated upon in the Department of Cardiothoracic Surgery at the Postgraduate Institute of Medical Education and Research, Chandigarh. These included 34 (87%) patients with benign tumors and 5 (13%) patients with primary malignant tumors. All the benign tumors were myxomas, of which 31 (91.2%) were in the left atrium and 3 (8.8%) in right atrium. Primary malignant tumors comprised 2 rhabdomyosarcomas, 1 angiosarcoma, 1 lymphoma and 1 case of pleomorphic malignant fibrous histiocytoma. The diagnosis was established by echocardiography, angiocardiography and computed tomography. In one case the diagnosis was made at autopsy. All myxomas, except tricuspid valve myxoma, were removed completely through right atrial or biatrial approach with the use of cardiopulmonary bypass. Four cases of primary malignant tumors were non-resectable. Near total resection of a malignant fibrous histiocytoma arising from the right middle pulmonary vein and left atrial junction was achieved. There were 2 operative deaths (5.1 %). The follow-up ranged from 3 months to 10 years with a mean of 5.7 years. There was 1 recurrence (2.9%) in the benign group. In the malignant group, 3 cases (60%) died within 5 to 8 months of surgery due to further local and metastatic spread of the tumor. The case of malignant fibrous histiocytoma was treated with postoperative radiotherapy to the right mediastinum and is doing well at follow-up 3 months after surgery.