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M C Cohen

Publications and source records attributed to M C Cohen.

83 records · Page 5Linked to original sources

The role of the cardiology consultant: putting it all together.

Consultation represents the act of providing advice regarding diagnosis and/or management and may comprise a major component of a cardiologist's practice. A frequent cause for cardiac consultation is preoperative risk assessment. With steadily decreasing morbidity and mortality related to noncardiac surgery, cardiovascular management strategies that are known to improve long-term outcomes should guide decision making in the perioperative setting. The preoperative cardiac consultation may represent an opportunity to initiate or modify cardiac care including primary and secondary preventive measures. A stepwise approach to perioperative cardiac risk assessment, as set forth by joint American College of Cardiology and American Heart Association guidelines, should be employed. The hallmark of successful preoperative cardiology consultation is effective communication with referring physicians. A consultant's good clinical judgement will only impact a patient's care if recommendations are communicated effectively. There is no substitution for direct, verbal contact. Recommendations should be kept to less than five when possible, be brief and specific. The consultant should provide contingency plans and follow-up. Good consultative technique increases compliance with recommendations and facilitates efficient patient care.

Algorithms↗

Histological analysis of coronary artery lesions in fatal postoperative myocardial infarction.

We sought to evaluate the underlying coronary pathology of fatal postoperative myocardial infarction (MI). It has been hypothesized that most MIs following noncardiac surgery occur in the setting of increased oxygen demand that exceeds coronary blood supply. However, most MIs not associated with surgery are caused by plaque rupture and intracoronary thrombosis. In a retrospective cohort study, we reviewed 1841 consecutive autopsy records from 1981 to 1995 at two institutions and identified 26 cases of postoperative MI with coronary arteries available. Plaque rupture was present in 12 cases (46%, 95% confidence interval [CI] 27%-67%). Of the 9 (35%) patients with intracoronary thrombus, 5 (56%; 19% of entire group) had total occlusion. Thrombus occurred on a >50% stenosis (by cross-sectional area) in a total of 33% (95% CI 16%-55%) of patients. The only statistically significant difference in clinical variables between patients with and without plaque rupture was longer interval from surgery to death in patients with plaque rupture (7.8+/-4.4 days versus 4.4+/-4.8 days; p = 0.047). In this autopsy series, coronary plaque rupture was associated with almost half of fatal postoperative MI cases. Strategies aimed at reducing triggers of plaque rupture with coronary occlusion might reduce postoperative MI fatality.

Aged↗

Neural network assessment of perioperative cardiac risk in vascular surgery patients.

Neural networks were developed to predict perioperative cardiac complications with data from 567 vascular surgery patients. Neural network scores were based on cardiac risk factors and dipyridamole thallium results. These scores were converted into likelihood ratios that predicted cardiac risk. The prognostic accuracy of the neural networks was similar to that of logistic regression models (ROC areas 76.0% vs 75.8%), but their calibration was better. Logistic regression overestimated event rates in a group of high-risk patients (predicted event rate, 64%; observed rate 30%; n=50, p<0.001). On a validation set of 514 patients, the neural networks still had ROC similar areas to those of logistic regression (68.3% vs 67.5%), but logistic regression again overestimated event rates for a group of high-risk patients. The calibration difference was reflected in the Hosmer-Lemeshow chi-square statistic (18.6 for the neural networks, 45.0 for logistic regression). The neural networks successfully estimated perioperative cardiac risk with better calibration than comparable logistic regression models.

Bayes Theorem↗

Mesenchymal hamartoma of the chest wall: a cooperative study with review of the literature.

The clinicopathologic features of three examples of mesenchymal hamartoma of the chest wall are described. The entity has been recorded under a number of names including osteochondroma, osteochondrosarcoma, benign chondroblastoma, mesenchymoma, and chondromatous hamartoma. The condition is manifest at birth or shortly thereafter with deformity of the chest wall and respiratory distress. Radiographic examination reveals a well-defined, partly calcified mass involving one or more ribs. The tumor is composed predominantly of chondroid tissue with large endothelium-lined blood spaces and immature mesenchyme with osteoclastic giant cells and osteoid. We review the literature and suggest that the lesion should be distinguished from aneurysmal bone cyst, chondroma, and other mesenchymal neoplasms. In order to avoid local recurrence the recommended treatment is complete surgical resection.

Bone Neoplasms↗

Types of anesthesia and cardiovascular outcomes in patients with congestive heart failure undergoing vascular surgery.

BACKGROUND. Whether regional anesthesia is preferable to general anesthesia for patients with congestive heart failure (CHF) undergoing noncardiac surgery remains controversial. The purpose of this study was to determine whether anesthetic technique affects postoperative cardiac outcome in patients with CHF; we hypothesized that cardiac outcomes would be superior with regional anesthesia compared with general anesthesia. DESIGN. 106 patients with prior or persistent CHF, undergoing femoral to distal artery bypass surgery, were randomized to general anesthesia (29 patients) or regional anesthesia (epidural, 42 patients, or spinal anesthesia, 35 patients). The primary end point was death or adverse cardiac events (myocardial infarction, unstable angina, or CHF). RESULTS. There was no statistically significant difference between groups in incidence of combined cardiac events, death, myocardial infarction, death or myocardial infarction combined, unstable angina, or CHF. CONCLUSION. Although larger studies are required to establish equivalence of the anesthetic strategies, this large single center study preliminarily indicates that regional anesthesia may not be superior to general anesthesia in patients with heart failure undergoing femoral to distal artery bypass surgery. (c)1999 by CHF, Inc.

Journal Article↗

Malignant ectomesenchymoma in childhood.

Five childhood malignant ectomesenchymomas are reported from three centers in three countries. The children were all younger than 3 years (four less than 12 months), four were boys, and four tumors were sited in the pelvis or external genitalia. All tumors had distinctive light microscopic features of rhabdomyosarcoma and three also demonstrated small numbers of included neuronal cells. Immunohistochemical studies and transmission electron microscopy revealed the additional presence of neurogenic components in the remaining two patients. An additional epithelial component was found by immunohistochemistry in one tumor, which suggests a pluripotential origin that still requires karyotypic investigation. Aggressive chemotherapy and adequate surgical excision have thus far been effective in providing disease-free follow-up for periods of 7 to 50 months. It is implied that because the biological behavior and morphology closely resemble those of rhabdomyosarcoma and because the neurogenic component is often inconspicuous, many malignant ectomesenchymomas may be misdiagnosed as rhabdomyosarcomas.

Child, Preschool↗

Pluripotential melanoblastoma, a unifying concept on malignancies arising in congenital melanocytic nevi: report of two cases.

Congenital melanocytic nevi are benign lesions present at birth and considered to be caused by a maldevelopment of the neural crest. The malignant potential of the congenital melanocytic nevi have been extensively addressed by several authors, and malignant melanoma is the most frequent neoplasm arising in these lesions. The present report describes two patients with congenital melanocytic nevi in which malignant melanoma with undifferentiated areas showing rhabdomyoblastic differentiation developed. The findings suggest that these mixed neoplasms may be recapitulating the differentiation potential of the ectomesenchyme-neural crest cells. We advocate the term "melanoblastoma" when referring to them.

Child↗

Effect of cytokines on tumour cell-endothelial interactions.

The adherence of tumour cells to microvascular endothelium is believed to be a necessary step in their migration to sites of metastasis. It has been proposed that this process occurs when cell surface molecules on tumour cells bind to complementary sites on endothelial cells. The expression of these endothelial-derived cell adhesion molecules appears to be modulated by cytokines, a broad class of protein mediators which play important roles in immune and inflammatory reactions. It has been found by ourselves and others that exposure of endothelium to some cytokines augments the adhesion of inflammatory cells as well as tumour cells in in vitro assays. We used a murine model consisting of P815 mastocytoma cells and microvascular endothelium and found that pretreatment of endothelial monolayers with TNF-alpha, IL-1, LPS or PMA augmented the number of tumour cells that attach in a dose-dependent fashion. FACS analysis showed that the change in binding was due to an increase in the expression of VCAM-1 on the surface of the endothelial cell. Methylxanthines (caffeine and theophylline) as well as "classical" calcium-mobilizing agents (ionomycin and thapsigargin) inhibited the expression of VCAM-1 in MME. We also studied the possible mechanisms of TNF-alpha signal transduction in endothelial cells. We examined the involvement of protein kinases in the TNF-alpha effect. Although we found that inhibitors of PKC could inhibit the TNF-alpha effect, our studies suggest that the "classical" PKC pathway is not completely responsible for signaling since TNF-alpha did not cause translocation of PKC to the cell membrane and its effect could not be completely mimicked by PMA. We also studied the effect of TGF-beta on the binding of tumour cells to endothelium. Exposure of endothelium to TGF-beta led to the inhibition of both basal and TNF-alpha enhanced binding of P815 cells. Inhibitors of G-proteins do not abolish TGF-beta action, and PKC and PKA activators elicit an opposite effect. However, TGF-beta-mediated inhibition of both basal binding and TNF-alpha-enhanced P815 binding to endothelium is completely abolished in the presence of the protein phosphatase inhibitor okadaic acid suggesting that TGF-beta elicits its effect by stimulating protein phosphatase activity.

Animals↗