Distinct alterations in sublingual microcirculatory blood flow and hemoglobin oxygenation in on-pump and off-pump coronary artery bypass graft surgery.

OBJECTIVE: The authors hypothesized that cardiopulmonary bypass (CPB) (on-pump) is associated with more severe changes in the microcirculatory blood flow and tissue oxygenation as compared with off-pump coronary artery bypass surgery. DESIGN: An observational study. SETTING: A university hospital and teaching hospital. PARTICIPANTS: Patients undergoing on-pump (n = 24) or off-pump (n = 24) cardiac surgery. INTERVENTIONS: Microcirculatory measurements were performed before CPB and 10 minutes after the switch to CPB or before and during cardiac luxation in off-pump patients. MEASUREMENTS AND MAIN RESULTS: Sublingual microcirculatory perfusion was investigated using side-stream dark field imaging, and sublingual microcirculatory oxygenation was measured using reflectance spectrophotometry. Conversion to CPB resulted in an increase in cardiac output from 4.0 ± 0.2 to 4.8 ± 0.3 L/min (p < 0.01) and a 40% reduction in arterial hemoglobin concentration. Cardiopulmonary bypass was associated with an increase in venular blood velocity from 349 ± 201 µm/s to 563 ± 227 µm/s (p < 0.05), a reduction in functional capillary density of 43%, and an increase in hemoglobin oxygenation of the red blood cells in the remaining filled capillaries from 47.2% ± 6.1% to 59.7% ± 5.2% (p < 0.001). The decrease in cardiac output during cardiac luxation from 4.5 ± 1.7 to 1.8 ± 0.8 L/min (p < 0.01) without hemoglobin changes was associated with a complete halt of capillary blood flow and a reduction in maximum capillary blood velocity from 895 ± 209 to 396 ± 178 µm/s (p < 0.01). The functional capillary density remained unchanged, whereas the hemoglobin oxygenation declined from 64.2% ± 9.1% to 48.6% ± 8.7% (p < 0.01). CONCLUSIONS: On-pump and off-pump cardiac surgery are associated with distinct alterations in sublingual microcirculatory perfusion and hemoglobin oxygenation. Although on-pump surgery results in a fall out of capillaries resulting in decreased oxygen extraction, off-pump surgery results in a cessation of flow during luxation resulting in decreased convection of oxygen transport.

A combined surgical and percutaneous approach through the axillary artery to introduce the Impella LP5.0 for short-term circulatory support.

We describe a novel axillary approach for insertion and usage of the Impella LP5.0, a low cost micro-axial flow pump, in five patients requiring circulatory support after acute ST-segment elevation myocardial infarction (STEMI). This alternative approach for implantation of the Impella LP5.0 has been proven simple, safe and feasible, and less invasive in severely compromised patients. Our hybrid, percutaneous and surgical, approach offered acute short-term circulatory support in STEMI patients with acute heart failure, allowing myocardial recovery or selection for long-term mechanical support.

Pulmonary arterial stent implantation in an adult with Williams syndrome.

We report a 38-year-old patient who presented with pulmonary hypertension and right ventricular dysfunction due to pulmonary artery stenoses as a manifestation of Williams syndrome, mimicking chronic thromboembolic pulmonary hypertension. The patient was treated with balloon angioplasty and stent implantation. Short-term follow-up showed a good clinical result with excellent patency of the stents but early restenosis of the segments in which only balloon angioplasty was performed. These stenoses were subsequently also treated successfully by stent implantation. Stent patency was observed 3 years after the first procedure.