Marvin M. Kirsh

Clinical outcome of patients with advanced coronary artery disease after viability studies with positron emission tomography

OBJECTIVE The aim of this study was to determine the prognostic significance of perfusion-metabolism imaging in patients undergoing positron emission tomography for myocardial viability assessment. BACKGROUND Positron emission tomography using nitrogen-13 ammonia and 18fluorodeoxyglucose to assess myocardial blood flow and metabolism has been shown to predict improvement in wall motion after coronary artery revascularization. The prognostic implications of metabolic imaging in patients with advanced coronary artery disease have not been investigated. METHODS Eighty-two patients with advanced coronary artery disease and impaired left ventricular function underwent positron emission tomographic imaging between August 1988 and March 1990 to assess myocardial viability before coronary artery revascularization. RESULTS Forty patients underwent successful revascularization. Patients who exhibited evidence of metabolically compromised myocardium by positron emission tomography (decreased blood flow with preserved metabolism) who did not undergo subsequent revascularization were more likely to experience a myocardial infarction, death, cardiac arrest or late revascularization due to development of new symptoms than were the other patient groups (p less than 0.01). Concordantly decreased flow and metabolism in segments of previous infarction did not affect outcome in patients with or without subsequent revascularization. Those with a compromised myocardium who did undergo revascularization were more likely to experience an improvement in functional class than were patients with preoperative positron emission tomographic findings of concordant decrease in flow and metabolism. CONCLUSIONS Positron emission tomographic myocardial viability imaging appears to identify patients at increased risk of having an adverse cardiac event or death. Patients with impaired left ventricular function and positron emission tomographic evidence for jeopardized myocardium appear to have the most benefit from a revascularization procedure.

Descending necrotizing mediastinitis: Transcervical drainage is not enough

One of the most lethal forms of mediastinitis is descending necrotizing mediastinitis, in which infection arising from the oropharynx spreads to the mediastinum. Two recently treated patients are reported, and the English-language literature on this disease is reviewed from 1960 to the present. Despite the development of computed tomographic scanning to aid in the early diagnosis of mediastinitis, the mortality for descending necrotizing mediastinitis has not changed over the past 30 years, in large part because of continued dependence on transcervical mediastinal drainage. Although transcervical drainage is usually effective in the treatment of acute mediastinitis due to a cervical esophageal perforation, this approach in the patient with descending necrotizing mediastinitis fails to provide adequate drainage and predisposes to sepsis and a poor outcome. In addition to cervical drainage, aggressive, early mediastinal exploration--debridement and drainage through a subxiphoid incision or thoracotomy--is advocated to salvage the patient with descending necrotizing mediastinitis.

Management of Tracheobronchial Disruption Secondary to Nonpenetrating Trauma

The pathogenesis, pathology, clinical presentation, diagnosis and management of tracheo-bronchial injuries secondary to nonpenetrating thoracic trauma are discussed.

Relation of regional function, perfusion and metabolism in patients with advanced coronary artery disease undergoing surgical revascularization

BACKGROUND Imaging of myocardial glucose metabolism using [18F]fluorodeoxyglucose (FDG) with positron emission tomography (PET) has been proposed for identification of tissue viability in patients with advanced coronary artery disease. This study was designed to evaluate the predictive value of flow and metabolic imaging for functional recovery after revascularization in myocardial segments of varying degrees of dysfunction. METHODS AND RESULTS Thirty-seven patients (mean age, 59 +/- 11 years) with coronary artery disease and impaired left ventricular function (ejection fraction, 34 +/- 10%) were studied with PET using FDG and [13N]ammonia before surgical coronary revascularization (3 +/- 1 grafts per patient). Tissue was scintigraphically characterized as normal, nonviable (concordant reduction of perfusion and FDG uptake), viable without discordance of perfusion and metabolism (mildly reduced perfusion and metabolism), or ischemically compromised (mismatch of reduced perfusion and maintained FDG uptake). Functional outcome was assessed by serial radionuclide ventriculography before and at 13 +/- 13 weeks (median interval of 8 weeks) after coronary revascularization. Preoperatively impaired regional wall motion improved significantly in ischemically compromised (mismatch) revascularized segments but not in nonviable myocardium or in viable myocardium without discordance of perfusion and metabolism. The negative predictive value of PET for functional recovery was 86%, whereas the positive predictive value in revascularized regions ranged from 48% to 86% depending on severity of baseline wall motion abnormalities. CONCLUSIONS PET identifies metabolically active tissue, which benefits from revascularization. Although the negative predictive value of PET for recovery was high, functional improvement of viable but ischemically compromised tissue was less frequent than previously reported. The predictive value of PET was highest in left ventricular segments with severe dysfunction and a mismatch or reduced perfusion but preserved metabolism. Integration of PET, angiographic, and functional data is necessary for the optimal selection of patients with advanced coronary artery disease and impaired left ventricular function for revascularization.

Impaired left ventricular contractile function in patients with long-term mitral regurgitation and normal ejection fraction☆☆☆

OBJECTIVES We tested the hypotheses that left ventricular chamber elastance would detect impaired contractile function in patients with long-term mitral regurgitation and a normal ejection fraction and that these patients would have unique temporal left ventricular size and ejection fraction responses to mitral valve surgery. BACKGROUND Although it has been suggested that left ventricular contractile function may begin deteriorating in patients with long-term mitral regurgitation whereas ejection fraction remains normal, no data exist in humans. METHODS We studied 11 control patients and 28 patients with long-term mitral regurgitation using micromanometer-measured pressures, biplane contrast cineventriculography and radionuclide angiography under control conditions and with alterations in load during right atrial pacing to calculate left ventricular chamber elastance and myocardial stiffness. RESULTS The patients with mitral regurgitation were classified into subgroups: Group I, normal contractile function; Group II, impaired contractile function (reduced Emax) but normal ejection fraction, and Group III, impaired contractile function (reduced Emax) with reduced systolic myocardial stiffness. Twenty-two of the patients with mitral regurgitation underwent mitral valve surgery. In Group I, comparable decreases in left ventricular volume indexes (p < 0.01 and p = 0.05, respectively) were associated with no change in ejection fraction at 3 months and 1 year. In contrast, in Group II, reductions in volume indexes (p < 0.0001 and p < 0.001) were associated with a short-term decrease in ejection fraction (p < 0.001) that recovered at 1 year (p < 0.01 vs. short-term). Finally, in Group III, variable responses in volume indexes were associated with a consistent decrease in ejection fraction at 3 months and 1 year. CONCLUSIONS An analysis of left ventricular chamber elastance provides data to support the concepts that 1) contractile function is impaired in some patients with long-term mitral regurgitation and a normal ejection fraction, 2) impaired contractile function may not be irreversible in all of these patients, and 3) an earlier consideration of mitral valve surgery may be warranted to preserve contractile function in these patients.

Complications of pulmonary resection.

The following complications of pulmonary resection are discussed with reference to their frequency of occurrence, etiology, diagnosis, and treatment: pulmonary insufficiency, arrhythmias, residual intrapleural air spaces, prolonged air leaks, postpneumonectomy empyema, bronchopleural fistula, cardiac herniation, lobar gangrene, esophagopleural fistula, pulmonary embolism, and tumor embolism.

Cardiogenic shock complicating acute myocardial infarction: The use of coronary angioplasty and the integration of the new support devices into patient management

Conventional therapy for cardiogenic shock complicating acute myocardial infarction continues to be associated with a high in-hospital mortality rate. Hemodynamic support with new mechanical devices and emergency coronary revascularization may alter the long-term prognosis for patients with this complication. Between July 1985 and March 1990, 68 patients presented to the University of Michigan with acute myocardial infarction and cardiogenic shock. Interventions performed included thrombolytic therapy (46%), intraaortic balloon pump counterpulsation (70%), cardiac catheterization (86%), coronary angioplasty (73%), emergency coronary artery bypass grafting/ventricular septal defect repair (15%), Hemopump insertion (11%), percutaneous cardiopulmonary support (4%) and ventricular assist device (3%). The 30-day survival rate was significantly better in patients who had successful angioplasty of the infarct-related artery than in patients with failed angioplasty (61% vs. 7%, p = 0.002) or no attempt at angioplasty (61% vs. 14%, p = 0.003). This difference was maintained over the 1-year follow-up period. The only clinical variable that predicted survival was age less than 65 years. The early use of the new support devices in 10 patients was associated with death in 8 (80%), but this poor outcome may reflect a selection bias for an especially high risk population. Collectively, these recent data continue to suggest that emergency revascularization with angioplasty may reduce the mortality rate, but further study is required to define optimal utilization and integration of new support devices.

Involvement of hydrogen peroxide and hydroxyl radical in the ‘oxygen paradox’: Reduction of creatine kinase release by catalase, allopurinol or deferoxamine, but not by superoxide dismutase **

The objective of this study was to test the hypothesis that cytotoxic oxygen metabolites participate in lytic cardiac cell damage, detected as creatine kinase release, upon reoxygenation of hypoxic, isolated buffer-perfused hearts (oxygen paradox). Perfusate additives included: superoxide dismutase (30 mg/l); catalase (2 mg/l); deferoxamine (0.5 mM); and allopurinol (1 mM). Creatine kinase release upon reoxygenation was reduced, to levels not significantly different from nonhypoxic controls, by adding either catalase, allopurinol or deferoxamine to the buffer during hypoxia. Reduced creatine kinase leakage was not accompanied by parallel preservation of ventricular function or coronary vascular resistance. Administration of catalase during hypoxia was superior to administering it only during reoxygenation. Treatment with catalase during both hypoxia and reoxygenation provided no more protection than administration only during hypoxia. The data suggest that an important component of hypoxia-induced cardiac cell damage is due primarily to hydrogen peroxide, which may then form hydroxyl radical. Superoxide anion plays an important role as a precursor of these species, but added superoxide dismutase alone did not significantly reduce creatine kinase loss. The data also suggest that damage resulting in creatine kinase release upon reoxygenation occurs during oxygen deprivation, and it is mediated in part by cytotoxic oxygen metabolites.

The treatment of acute traumatic rupture of the aorta: A 10 year experience

Forty-three patients with aortic rupture secondardy to blunt trauma have been treated at the University of Michigan within the past 10 years with an overall salvage rate of 70%. The diagnosis should be suspected in anyone who has sustained a high speed decelerating injury, if the chest roentgenograrm shows media-stinal widening, whether or not there is hypertension of the upper extremities; systolic murmur, or external evidence of chest injury. Aortography should be employed to confirm the diagnosis and to determine the site or sites of rupture. Repair of the lesion should be undertaken as soon as possible and takes priority in most instances over associated injuries. Repair in almost all cases can be accomplished safely and quickly using a bypass shunt without the aid of extra-corporeal circulation.

Carcinoma of the Lung: Results of Treatment over Ten Years

Mediastinal lymph node dissection in conjunction with pulmonary resection was performed on 437 patients with bronchogenic carcinoma at the University of Michigan Medical Center from 1959 to 1969. The absolute five- and ten-year survival rates for patients undergoing curative resection were 36.2 and 14.4%, respectively. The five-year survival of those without nodal metastases was 49.3%, and it was 31.1% in patients with hilar metastases only. The five-year survival of patients with mediastinal metastases who received radiation therapy was 23.1%. Of the 193 patients with squamous cell carcinoma, 43% lived five years free from disease. The five-year survival of patients undergoing resection who had no hilar lymph node metastases was 53%, and it was 47.5% in those with hilar metastases only. The five-year survival in patients with mediastinal metastases who received postoperative irradiation was 34.4%.