Intraoperative diagnosis of stanford type a dissection by transesophageal echocardiogram in a patient presenting for renal transplantation.

A 48-year-old patient with hypertensive end-stage renal disease presented for cadaveric renal transplantation. On physical exam, a previously undocumented diastolic murmur was heard loudest at the left lower sternal border. The patient had a history of pericardial effusions and reported "a feeling of chest fullness" when lying flat. As such, a transesophageal echocardiogram (TEE) was performed after induction of anesthesia to evaluate the pericardial space and possibly determine the etiology and severity of the new murmur. The TEE revealed a Stanford Type A aortic dissection. The renal transplant was cancelled (organ reassigned within region), and the patient underwent an urgent ascending and proximal hemiarch aortic replacement. This case demonstrates the importance of a thorough physical exam and highlights the utility of TEE for noncardiac surgical cases.

Acute occlusion of a bileaflet mechanical mitral valve prosthesis resulting from external cardiac compression.

A 45-year-old woman with a history of rheumatic mitral disease underwent valve replacement. After surgery, the patient became hemodynamically unstable. A transesophageal echocardiogram showed an underfilled left ventricle with a clot impinging on the lateral aspect of the left ventricle and a malfunctioning mitral valve prosthesis. After evacuation of the clot in the operating room, the mitral valve prosthesis began functioning normally. The prosthesis malfunction resulted from external cardiac compression. This dynamic device malfunction was replicated when the surgeon compressed the lateral aspect of the heart. To our knowledge, this dynamic form of leaflet dysfunction from external compression has not been described. This case highlights the importance of closely evaluating prosthetic valve function in the setting of hemodynamic deterioration.

Congenital supravalvular aortic stenosis and sudden death associated with anesthesia: what's the mystery?

Patients with congenital supravalvular aortic stenosis and associated peripheral pulmonary artery stenoses, the majority of whom have Williams-Beuren syndrome, are inherently at risk for development of myocardial ischemia. This is particularly true in the setting of procedural sedation and anesthesia. The biventricular hypertrophy that accompanies these lesions increases myocardial oxygen consumption and compromises oxygen delivery. In addition, these patients often have direct, multifactorial compromise of coronary blood flow. In this article, we review both the pathophysiology of congenital supravalvular aortic stenosis and the literature regarding sudden death in association with sedation and anesthesia. Recommendations as to preoperative assessment and management of these patients are made based on the best available evidence.

Hemostatic analysis of a 13 year old with antiphospholipid syndrome and restrictive pericarditis.

Antiphospholipid syndrome is an autoimmune thrombophilic disorder that is uncommon in adults and remarkably rare in children. Thrombotic etiological factors are variable in antiphospholipid syndrome, including antibody-antigen complex-mediated platelet activation, inhibition of anticoagulants, or attenuation of fibrinolysis. We present the case of a child with antiphospholipid syndrome presenting with syncope, constrictive pericarditis and hepatic enlargement that was found to have platelet-mediated hypercoagulability and marked clot lysis via thrombelastography in the preoperative period. Restoration of circulation following pericardectomy and inotropic support was associated with attenuation of hypercoagulability and fibrinolysis. It is concluded that the etiological factors responsible for antiphospholipid syndrome-mediated hemostatic abnormalities and the probable effects of hepatic hypoperfusion on clot lysis in this patient were detected with thrombelastography, and similar thrombelastographic analyses are recommended to compliment standard coagulation assessments of patients with antiphospholipid syndrome.

The impact of factor XIII on coagulation kinetics and clot strength determined by thrombelastography.

Fibrinogen has been shown to be responsible for most protein-mediated clot strength via thrombelastography. However, factor XIII (FXIII) activity also plays a prominent role in the development of clot strength. Thus, we hypothesized that changes in FXIII activity would significantly increase clot strength. FXIII (0%, 1%, 6.25%, 12.5%, 25%, 50%, and 100% normal activity) was placed in a fixed volume of citrated FXIII-deficient plasma with 1% tissue factor and calcium chloride and underwent thrombelastography for 10 min. We measured the variables reaction time (R; a measurement of clot initiation), alpha (a measure of the rate of clot formation), amplitude (A; a measure of clot strength), and shear elastic modulus (G; a measure of clot strength). FXIII activity significantly decreased R in a pattern of exponential decay (R2 = 0.77; P < 0.001). FXIII activity significantly increased alpha, following a sigmoidal pattern (R2 = 0.88; P < 0.001). Finally, increases in FXIII activity significantly increased A and G in a sigmoidal pattern (R = 0.89; P < 0.001). We concluded that FXHI significantly affects R, alpha, A, and G. Thus, transfusion decision making with protein-mediated thrombelastographic patterns must account for the contribution of both fibrinogen and FXIII.