Can technetium 99m pyrophosphate be used to quantify myocardial injury in donor hearts?

BACKGROUND: There are no prospective methods available to quantify the myocyte injury in hearts prior to transplantation. The potential of the isotope labeled infarct marker 99m Technetium pyrophosphate (TcPPT) being used in this role was investigated. METHODS: Brain death was induced by creating an extradural space occupying lesion in young adult swine after which hemodynamic changes were monitored and myocyte injury was quantified by histochemistry. TcPPT was administered 5 hours after induction of intracranial hypertension, and after hearts were harvested myocardial uptake was measured. These latter measurements were related to the histochemical assessment of myocyte injury. RESULTS: Sham animals (n = 4) maintained cardiovascular stability and experienced minimal myocyte injury, grades 0 to 3. BD animals (n = 10) exhibited varying patterns of hemodynamic change and myocyte injury, the latter was significant in 6, graded 4 to 11, p less than 0.05. Uptake of TcPPT by BD hearts was greater than twice the 90th centile sham value in 6. The sensitivity and specificity of greater uptake indicating the presence of myocyte injury was 83.3% and 75% respectively. CONCLUSIONS: TcPPT has the potential to quantify myocardial injury induced by brain death and its potential utility merits further investigation.

Magnesium and cardiac surgery.

Magnesium depletion was found to occur commonly after cardiac surgery in children and to cause significant neurological and cardiac symptoms. This discovery, in the absence of previous detailed documentation, inspired investigations to determine the relationship of cardiac surgery to changes in magnesium metabolism. A number of patient groups were studied, including both children and adults undergoing various operations. The studies demonstrated an almost universal occurrence of magnesium depletion during and after cardiac surgery, but also demonstrated that supplementation may be preventive. The patterns and aetiology of the changes and their clinical significance are presented and discussed in the light of recent reports from other authors.

Giant pericardial cysts.

Pericardial cysts are most commonly incidental radiologic findings of little clinical consequence. We present the unusual history of 2 patients in whom pericardial cysts were of massive sizes and caused significant symptoms; in 1, progression of the cyst size had been documented over 25 years. Diagnostic difficulties encountered and the utility of video-assisted thoracoscopy are described.

Influence of heparin thromboprophylaxis on plasma leucocyte elastase levels following lobectomy for lung carcinoma.

Recent in vitro studies and animal investigation indicate that plasma leucocyte elastase (PLE) can dissolve pulmonary structural proteins, such as elastin, and produce lesions in the lung similar to that seen in adult respiratory distress syndrome (ARDS) and emphysema. In contrast, heparin strongly inhibits PLE and protects elastin from elastolysis. On the basis of these findings, PLE levels were monitored in 24 patients with non-small cell lung carcinoma (NSCLC) undergoing lobectomy. Ten patients from Killingbeck Hospital (Group 1) received 5000 IU subcutaneous (s.c.) heparin commenced 2 h prior to surgery and continued at 8 h intervals until the patient was fully ambulatory. Fourteen patients from Bradford Royal Infirmary (Group 2) received no heparin as standard policy. There was no significant difference in pre-operative PLE levels between groups. The post operative PLE levels in both groups increased significantly (P < 0.02) on the first post operation day (POD). However, PLE levels of Group 2 were 2.5 to 5.3 times higher than those of Group 1 at each postoperative interval (first, third, and seventh POD) respectively (0.002 < P < 0.02). There was no difference in blood loss between groups (P = 0.17). These results indicate that post operative PLE activity is elevated in NSCLC patients following lobectomy and s.c. heparin administration as thromboprophylaxis may inhibit PLE activity post operatively without increasing blood loss. Therefore, heparin may have a role to play in protecting lung tissue against the pulmonary lesions caused by proteolytic activity of PLE, and theoretically reduce post-operative complications, such as ARDS or emphysema.

Magnesium flux during and after open heart operations in children.

Hypomagnesemia and depletion of the body's magnesium stores is known to be associated with an increased incidence of both cardiac arrhythmias and neurological irritability. In a two-part prospective study we have evaluated whether magnesium deficiency is a significant occurrence in children treated in the intensive care unit after open heart operations, and subsequently have sought to identify how intraoperative metabolic changes were related to the resultant findings. In 41 children studied after operation the plasma magnesium concentration showed a significant decrease from 0.92 mmol/L (10th to 90th centile, 0.71 to 1.15 mmol/L) immediately after operation to 0.77 mmol/L (0.65 to 0.91 mmol/L) on the following morning. The subsequent change in grouped values was not significant but 14 (34.2%) and 7 (17.1%) possessed values of less than 0.7 mmol/L and 0.6 mmol/L, respectively. The occurrence of cardiac arrhythmias was not statistically related to the occurrence of hypomagnesemia. In 21 children perioperative changes in extracellular and tissue magnesium, potassium, and calcium content were measured. It was found that hemodilution with a prime low in magnesium caused a reduction from a median of 0.81 mmol/L to 0.61 mmol/L (p < 0.01). Plasma potassium level, however, was elevated from 3.7 mmol/L to 4.15 mmol/L (p < 0.05) and the ionized calcium content from 1.17 mmol/L (1.07 to 1.25 mmol/L) to 1.49 mmol/L (1.25 to 2.56 mmol/L) (p = 0.0009). The myocardial content of magnesium did not change significantly but skeletal muscle content was depleted from 6.75 mumol/g (2.85 to 8.35 mumol/g) to 5.65 mumol/g (2.45 to 7.2 mumol/g) (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Results of pneumonectomy for cancer in patients with limited ventilatory function.

It is well established that patients with compromised pulmonary function have a greater incidence of morbidity and mortality following lung resection. The prognosis of 36 (9.7%) patients with poor respiratory function (forced expiratory volume in ls (FEV1) and FEV1/FVC (forced vital capacity) ratio were equal to or less than 50% of the predicted value) of a total of 369 patients who underwent pneumonectomy due to non-small cell lung carcinoma over 10 years were reviewed. All but three patients were male with a median age of 62.5 years. Right pneumonectomy was carried out in 12 (33%) and left in 24 (67%) patients. Median FEV1 and FEV1/FVC were 1.51 (46%) and 46.5% respectively. Three (8%) patients died within 30 days of surgery. The postoperative complication rate in patients with poor respiratory function was 44%. Nine (27%) of the hospital survivors died due to non-malignant causes (recurrent chest infection/respiratory failure) and 12 (36%) due to recurrent tumour. The cause of death in one patient was second primary lung tumour and it was unknown in three (9%) patients. Eight (24%) long-term surviving patients did not have severe respiratory symptoms; their FEV1 and FEV1/FVC were remeasured and revealed a median 1.05 l (38%) and 50%, respectively of the predicted value. Actuarial 5-year survival was 29%. Poor respiratory function is associated with postoperative complications and non-malignant deaths arising secondary to respiratory failure. The survival profile demonstrates that patients were successfully treated with pneumonectomy and suggests that surgery should not be withheld from those with limited lung function if detailed investigations predict adequate residual lung function.

Magnesium flux caused by coronary artery bypass operation: three patterns of deficiency.

We undertook a study to evaluate the patterns of magnesium deficiency that may develop during and following coronary artery bypass operation without cardioplegia. In 18 patients intraoperative measurements of plasma magnesium and potassium concentrations and measurements of cardiac and skeletal muscle content of these ions were taken. The changes in plasma concentrations and excretion were evaluated postoperatively. Hemodilution at initiation of cardiopulmonary bypass caused a 17.3% decrease in plasma magnesium concentration (p < 0.01), which persisted until the first postoperative day. By the fifth postoperative day the level was 19.5% greater than the preoperative value. Urinary excretion of magnesium reflected changes in plasma magnesium concentration. Cardiac muscle content of magnesium decreased by 13.3%. Plasma potassium concentration was elevated by hemodilution (p < 0.01), and muscle potassium was not depleted. We conclude that three patterns of magnesium depletion occur: hemodilution, intraoperative cellular depletion, and postoperative cellular depletion. The findings support the need for magnesium supplementation during and after cardiac operation.

Angioscopy-guided training model of coronary artery anastomosis.

Surgical models are proving invaluable in the training of junior surgeons or in the development of new skills by senior surgeons. We have developed a model in which coronary artery anastomoses may be performed and evaluated with an angioscope, thus facilitating development of skills.

Fate of patients with residual tumour at the bronchial resection margin.

The presence of microscopic deposits of tumour cells at the bronchial resection margin (BRM) may adversely affect the prognosis of patients. Residual tumour cells were identified at the BRM in 40 (5.4%) of 735 patients who had been operated on for non-small cell lung carcinoma (NSCLC). The extent of disease was stage I in 7 (17.5%), stage II in 21 (52.5%), stage IIIa in 10 (25%) and stage IIIb in 2 (5%) patients. Malignant cells were found to have infiltrated the submucosal lymphatics in 5 (12.5%) cases and the peribronchial tissue in the remaining 35 (87.5%). Fifteen (37.5%) patients received adjuvant radiotherapy (RT). Recurrence of the disease was diagnosed in 29 (72.5%) patients after a median of 17 months (range 3-111). The recurrence was local in 17 (59%) and distant in 12 (41%). The 5-year overall actuarial survival rate was 21.6% and was not affected by RT (P = NS). Only patients with stage IIIa disease and a positive bronchial stump had a significantly reduced 5-year survival rate compared to those with a negative stump, 0% vs 17% (P < 0.001). Tumour cells at the resection margin did not affect the survival in this cohort except those with stage IIIa disease, and the addition of adjuvant RT did not significantly affect its recurrence in patients with NSCLC.

Recurrence of rectal carcinoma in the mediastinum.

Mediastinal metastases arising from a primary gastrointestinal neoplasm usually follow extensive subdiaphragmatic spread. However, we have reported the rare recurrence of rectal carcinoma in the mediastinum. In addition to emphasizing the systemic metastatic spread of rectal carcinoma, this case demonstrates the need to consider metastases arising from abdominal tumors as a cause of mediastinal masses.

Iatrogenic peritoneopericardial hernia following coronary artery bypass surgery.

Intrapericardial diaphragmatic herniation of the stomach is reported in a patient who had undergone coronary artery bypass surgery 6 years earlier. The peritoneopericardial defect was iatrogenic and emphasizes the danger of inadvertent diaphragmatic injury during cardiac surgery.

Multiple pulmonary microemboli complicating pneumonectomy.

Pulmonary embolism is widely recognized to complicate abdominal and lower limb orthopedic surgical procedures, but in comparison, it is seldom recognized to hamper the postoperative progress of patients after thoracic operations. We present 4 patients in whom multiple pulmonary emboli developed after pneumonectomy, 2 of whom were treated successfully. We discuss the mostly atypical presentation and the physiological and clinical consequences, and also suggest a mode of management.