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Background: If long-term use of left ventricular assist devices (LVADs) as bridges to transplantation is successful, the issue of permanent device implantation in lieu of transplantation could be addressed through the creation of appropriately designed trials. Our medium-term experience with both pneumatically and electrically powered ThermoCardiosystems LVADs is presented to outline the benefits and limitations of device support in lieu of transplantation., Methods and Results: Detailed records were kept prospectively for all patients undergoing LVAD insertion. Fifty-eight LVADs were inserted over 5 years, with a survival rate of 74%. Mean patient age was 50 years, and duration of support averaged 98 days. Although common, both preexisting infection and infection during LVAD support were not associated with increased mortality or decreased rate of successful transplantation. Thromboembolic complications were rare, occurring in only three patients (5%) despite the absence of anticoagulation. Ventricular arrhythmias were well tolerated in all patients except in cases of early perioperative right ventricular failure, with no deaths. Right ventricular failure occurred in one third of patients and was managed in a small percentage by right ventricular assist device (RVAD) support and/or inhaled nitric oxide therapy. There were no serious device malfunctions, but five graft-related hemorrhages resulted in two deaths. Finally, a variety of noncardiac surgical procedures were performed in LVAD recipients, with no major morbidity and mortality., Conclusions: Over all, our medium-term experience with implantable LVAD support is encouraging. Although additional areas of investigation exist, improvements in patients selection and management together with device alterations that have reduced the thromboembolic incidence and facilitated patient rehabilitation lead us to believe that a prospective, randomized trial is indicated to study the role that LVADs may have as an alternative to medical management.

Background: The hypotension of septic shock is due to systemic vasodilation. On the basis of a clinical observation, we investigated the possibility that a deficiency in vasopressin contributes to the vasodilation of septic shock., Methods and Results: In 19 patients with vasodilatory septic shock (systolic arterial pressure [SAP] of 92 +/- 2 mm Hg [mean +/- SE], cardiac output [CO] of 6.8 +/- 0.7 L/min) who were receiving catecholamines, plasma vasopressin averaged 3.1 +/- 1.0 pg/mL. In 12 patients with cardiogenic shock (SAP, 99 +/- 7 mm Hg; CO, 3.5 +/- 0.9 L/min) who were also receiving catecholamines, it averaged 22.7 +/- 2.2 pg/mL (P < .001). A constant infusion of exogenous vasopressin to 2 patients with septic shock resulted in the expected plasma concentration, indicating that catabolism of vasopressin is not increased in this condition. Although vasopressin is a weak pressor in normal subjects, its administration at 0.04 U/min to 10 patients with septic shock who were receiving catecholamines increased arterial pressure (systolic/diastolic) from 92/52 to 146/66 mm Hg (P < .001/P < .05) due to peripheral vasoconstriction (systemic vascular resistance increased from 644 to 1187 dyne.s/cm5; P < .001). Furthermore, in 6 patients with septic shock who were receiving vasopressin as the sole pressor, vasopressin withdrawal resulted in hypotension (SAP, 83 +/- 3 mm Hg), and vasopressin administration at 0.01 U/min, which resulted in a plasma concentration (approximately 30 pg/mL) expected for the level of hypotension, increased SAP from 83 to 115 mm Hg (P < .01)., Conclusions: Vasopressin plasma levels are inappropriately low in vasodilatory shock, most likely because of impaired baroreflex-mediated secretion. The deficiency in vasopressin contributes to the hypotension of vasodilatory septic shock.

Background: The Frank-Starling mechanism is one of the most important physiological principles for regulation of contractile performance. We therefore studied the question of whether this mechanism may be absent or attenuated in end-stage failing human left ventricular myocardium., Methods and Results: Different methodological approaches were used to analyze the effects of this mechanism on the organ, tissue, and sarcomere levels: (1) In excised human whole left ventricles (2 donor hearts, 5 failing hearts), diastolic and systolic pressure-volume relationships were obtained. (2) In isolated muscle strip preparations from the left ventricular wall of donor hearts (n = 14) and failing hearts from patients with idiopathic dilated cardiomyopathy (n = 21) and ischemic cardiomyopathy (n = 11), peak developed force was measured at different muscle lengths of the preparation. (3) Skinned fiber preparations were obtained from failing right and left ventricles (n = 12). In all three studies, we clearly observed the existence of the Frank-Starling mechanism: (1) In isolated failing human left ventricles, peak developed isometric pressure is increased when the preload is elevated. (2) Peak developed tension is increased by approximately 50% to 70% (P < .01) in left ventricular preparations of failing and nonfailing ventricles when the muscles are stretched from 90% to 100% optimum length. (3) An increase in sarcomere length leads to a sensitization of contractile proteins of ventricular skinned fiber preparations from failing human hearts. At 1.9-microns sarcomere length, the EC50 value was 5.56 +/- 0.06, and at 2.3 microns it was 5.70 +/- 0.05 (P < .01; n = 7)., Conclusions: The Frank-Starling mechanism is maintained in end-stage failing human hearts, whereas significant alterations of diastolic myocardial distensibility are evident in chronic heart failure.