Patient Selection and Outcomes of Transfemoral Transcatheter Aortic Valve Replacement Performed with Monitored Anesthesia Care Versus General Anesthesia.

OBJECTIVE: The aim of this study was to compare outcomes of monitored anesthesia care (MAC) versus general anesthesia (GA) for transfemoral transcatheter aortic valve replacement (TF-TAVR) and to describe a selection process for the administration of MAC. DESIGN: Retrospective analysis of patients who underwent TF-TAVR under MAC or GA. SETTING: Department of Cardiac Anesthesia, Albany Medical Center, a tertiary university hospital. PARTICIPANTS: Patients selected for TF-TAVR. INTERVENTIONS: Patients were divided into those who underwent MAC and those who underwent GA. MEASUREMENTS AND MAIN RESULTS: The study comprised 104 consecutive patients (55% male, mean age 83 years) who underwent TF-TAVR under MAC (n = 60) or GA (n = 37) from 2014 to 2015. Seven patients were converted from MAC to GA and were omitted from analysis. There was no statistically significant difference between 30-day mortality and complications between the 2 groups. The MAC group had a significantly shorter median intensive care unit length of stay (48 h v 74 h, p = 0.0002). The MAC group also demonstrated reduced procedural time (45.5 min v 62 min, p = 0.003); operating room time (111 min v 153 min, p = <0.001); and fluoroscopy time (650 s v 690 s, p = 0.03). CONCLUSIONS: Patient selection for TF-TAVR with MAC can be formalized and implemented successfully. MAC allows for the minimizing of patient exposure to unnecessary interventions and improving resource utilization in suitable TAVR patients. Selection requires a multidisciplinary clinical decision-making process. MAC demonstrates good outcomes compared with GA, yet it is important to have a cardiac anesthesiologist present in the event of emergency conversion to GA.

Use of ultra pure nitric oxide generated by the reduction of nitrogen dioxide to reverse pulmonary hypertension in hypoxemic swine.

Inhaled nitric oxide (NO) has the capacity to selectively dilate pulmonary blood vessels, and thus enhance the matching of ventilation and perfusion, improve oxygenation and decrease pulmonary hypertension. However, existing approaches for the administration of inhaled NO are associated with the co-delivery of potentially toxic concentrations of nitrogen dioxide (NO2) due to the oxidation of NO in oxygen rich environments. We tested the ability of a novel methodology for generating highly purified NO through the reduction of NO2 by ascorbic acid to reverse pulmonary hypertension. In vitro testing demonstrated that the NO output of the novel device is ultrapure and free of NO2. An in vivo hypoxemic swine model of pulmonary hypertension was used to examine the dose response to NO in terms of pulmonary pressures and pulmonary vascular resistance. Pulmonary hypertension was induced by lowering inspired oxygen to 15% prior to treatment with inhaled ultra purified NO (1, 5, 20, and 80PPM). Hypoxemia increased mean pulmonary artery pressures and pulmonary vascular resistance. Inhaled ultra purified NO doses (down to 1PPM) show a marked reduction of hypoxemia-induced pulmonary vascular resistance. These experiments demonstrate a simple and robust method to generate purified inhaled NO that is devoid of NO2 and capable of reversing hypoxemia induced pulmonary hypertension.

Baseline hemodynamic and echocardiographic indices in anesthetized calves.

The experimental calf model is used to assess mechanical circulatory support devices and prosthetic heart valves. Baseline indices of cardiac function have been established for the normal awake calf but not for the anesthetized calf. Therefore, we gathered hemodynamic and echocardiographic data from 16 healthy anesthetized calves (mean age, 189.0 +/- 87.0 days; mean body weight, 106.9 +/- 32.3 kg) by cardiac catheterization and noninvasive echocardiography, respectively. Baseline hemodynamic data included heart rate (65 +/- 12 beats per minute), mean aortic pressure (113.5 +/- 17.4 mm Hg), left ventricular end-diastolic pressure (16.3 +/- 38.9 mm Hg), and mean pulmonary artery pressure (21.7 +/- 8.3 mm Hg). Baseline two-dimensional echocardiographic data included left ventricular systolic dimension (3.5 +/- 0.7 cm), left ventricular diastolic dimension (5.6 +/- 0.8 cm), end-systolic intraventricular septal thickness (1.7 +/- 0.2 cm), end-diastolic intraventricular septal thickness (1.2 +/- 0.2 cm), ejection fraction (63 +/- 10%), and fractional shortening (37 +/- 10%). Doppler echocardiography revealed a maximum aortic valve velocity of 0.9 +/- 0.5 m/s and a cardiac index of 3.7 +/- 1.1 L/minute/m2. The collected baseline data will be useful in assessing prosthetic heart valves, cardiac assist pumps, new cannulation techniques, and robotics applications in the anesthetized calf model and in developing calf models of various cardiovascular diseases.

Myocardial hemodynamics, physiology, and perfusion with an axial flow left ventricular assist device in the calf.

The Jarvik 2000 axial flow left ventricular assist device (LVAD) is used clinically as a bridge to transplantation or as destination therapy in end-stage heart disease. The effect of the pump's continuous flow output on myocardial and end-organ blood flow has not been studied experimentally. To address this, the Jarvik 2000 pump was implanted in eight calves and then operated at speeds ranging from 8,000 to 12,000 rpm. Micromanometry, echocardiography, and blood oxygenation measurements were used to assess changes in hemodynamics, cardiac dimensions, and myocardial metabolism, respectively, at different speeds as compared with baseline (pump off, 0 rpm) in this experimental model. Microsphere studies were performed to assess the effects on heart, kidney, and brain perfusion at different speeds. The Jarvik 2000 pump unloaded the left ventricle and reduced end-diastolic pressures and left ventricular dimensions, particularly at higher pump speeds. The ratio of myocardial oxygen consumption to coronary blood flow and the ratio of subendocardial to subepicardial blood flow remained constant. Optimal adjustment of pump speed and volume status allowed opening of the aortic valve and contribution of the native left ventricle to cardiac output, even at the maximum pump speed. Neither brain nor kidney microcirculation was adversely affected at any pump speed. We conclude that the Jarvik 2000 pump adequately unloads the left ventricle without compromising myocardial metabolism or end-organ perfusion.