New insights into the pathophysiology of cardiogenic shock: the role of the microcirculation.

PURPOSE OF REVIEW: The ultimate goal of therapy for cardiogenic shock is to restore microcirculatory function and thereby restore the oxygen supply to sustain cellular function. Therapeutic measures mainly focus on improving pressure-derived macrocirculatory parameters. However, it is increasingly clear that to achieve significant progress in treatment, microcirculatory physiopathological mechanisms must be considered. RECENT FINDINGS: Microcirculatory function deteriorated during cardiogenic shock and improved after treatment. Postcardiogenic shock microcirculatory disturbances, both myocardial and peripheral, were a prognostic factor for the long-term outcome. Hypothermia, whether pharmacologically or physically induced, improved postresuscitation myocardial and cerebral function, an effect associated with improved postresuscitation microcirculation. The impact of cardiogenic shock on cerebral and myocardial microcirculation could be evaluated with MRI. In severe heart failure, pharmacological interventions improved microcirculation. An assessment of the microcirculation was often performed using handheld video microscopy for direct observation of the sublingual microcirculation, which proved to be useful for evaluating the effects of interventions during cardiogenic shock. A large multicenter study on critically ill patients is now being conducted using this technique. SUMMARY: Cardiogenic shock induces microcirculatory disorders that can be monitored and influenced in various manners, both pharmacologically and physically. In addition to global hemodynamic optimization, interventions must also ameliorate the microcirculation.

The significance of angiogenesis in malignant pheochromocytomas.

The purpose of this study was to investigate tumor angiogenesis in a series of benign and malignant pheochromocytomas and to determine whether there is a correlation between angiogenesis and the presence of distant metastases. In this study, the CD31 monoclonal antibody was selected to measure intratumoral microvessel density. Nineteen patients with malignant pheochromocytomas and nineteen patients with benign pheochromocytomas who underwent operation were studied. In order to quantify intratumoral microvessel density, the total number of pixels of CD31-positive reactivity was assessed and expressed as a percentage of the total tissue area in the analyzed field. Analysis of variance revealed a statistically significant correlation between malignancy and intratumoral microvessel density (p = 0.0009). Although there was a considerable variability in the intratumoral microvessel density from tumor to tumor within both the benign and the malignant group, a percentage of more than 28.5% anti-CD31 stained area was found only in malignant tumors. In conclusion, this study shows that the mean intratumoral microvessel density in malignant pheochromocytomas is increased approximately twofold as compared with benign tumors. However, the clinical significance of this prognostic marker is rather weak, because only 4 of the 19 malignant pheochromocytomas had microvessel density higher than this threshold of 28.5%.

Safe retroperitoneal endoscopic resection of pheochromocytomas.

Although endoscopic adrenalectomy is advocated for small adrenocortical tumors, questions remain about the safety of endoscopic retroperitoneal resection of pheochromocytomas. In this study we evaluated the outcome of retroperitoneal endoscopic adrenalectomy for pheochromocytoma. Between June 1995 and September 1999 we performed 18 retroperitoneal endoscopic adrenalectomies for a pheochromocytoma or paraganglioma. All patients received adequate alpha-adrenergic blockade. The adrenal vein was ligated at the end of the procedure. Operative blood pressure values were recorded and evaluated. Altogether 15 patients (11 women, 4 men; mean age 47.2 years) were operated on for 17 pheochromocytomas and 1 extraadrenal tumor (4 right, 11 left, 3 bilateral). One female patient was operated on at 13 weeks' gestation. Hypertensive episodes at operation were seen in 4 (26.7%) patients, and tachycardia occurred in 5 (33%). Hemodynamic changes could be corrected in all cases using simple measures without morbidity or detrimental effects. The mean operating time was 125 minutes (80-180 minutes), and the conversion rate was 5.6% (1/18). The median hospital stay was 5 days (3-28 days). Morbidity was 20% (3/15). Endoscopic retroperitoneal adrenalectomy for pheochromocytoma is safe and effective, and it is associated with limited morbidity.