Improvement of sidestream dark field imaging with an image acquisition stabilizer.

BACKGROUND: In the present study we developed, evaluated in volunteers, and clinically validated an image acquisition stabilizer (IAS) for Sidestream Dark Field (SDF) imaging. METHODS: The IAS is a stainless steel sterilizable ring which fits around the SDF probe tip. The IAS creates adhesion to the imaged tissue by application of negative pressure. The effects of the IAS on the sublingual microcirculatory flow velocities, the force required to induce pressure artifacts (PA), the time to acquire a stable image, and the duration of stable imaging were assessed in healthy volunteers. To demonstrate the clinical applicability of the SDF setup in combination with the IAS, simultaneous bilateral sublingual imaging of the microcirculation were performed during a lung recruitment maneuver (LRM) in mechanically ventilated critically ill patients. One SDF device was operated handheld; the second was fitted with the IAS and held in position by a mechanic arm. Lateral drift, number of losses of image stability and duration of stable imaging of the two methods were compared. RESULTS: Five healthy volunteers were studied. The IAS did not affect microcirculatory flow velocities. A significantly greater force had to applied onto the tissue to induced PA with compared to without IAS (0.25 +/- 0.15 N without vs. 0.62 +/- 0.05 N with the IAS, p < 0.001). The IAS ensured an increased duration of a stable image sequence (8 +/- 2 s without vs. 42 +/- 8 s with the IAS, p < 0.001). The time required to obtain a stable image sequence was similar with and without the IAS. In eight mechanically ventilated patients undergoing a LRM the use of the IAS resulted in a significantly reduced image drifting and enabled the acquisition of significantly longer stable image sequences (24 +/- 5 s without vs. 67 +/- 14 s with the IAS, p = 0.006). CONCLUSIONS: The present study has validated the use of an IAS for improvement of SDF imaging by demonstrating that the IAS did not affect microcirculatory perfusion in the microscopic field of view. The IAS improved both axial and lateral SDF image stability and thereby increased the critical force required to induce pressure artifacts. The IAS ensured a significantly increased duration of maintaining a stable image sequence.

Creatinine clearance is independently associated with one year mortality in a primary PCI cohort with cardiogenic shock.

BACKGROUND: Acute ST-segment elevation myocardial infarction (STEMI) complicated with cardiogenic shock (CS) has still the highest in hospital mortality. Patients with STEMI and increasing creatinine levels within 24 h after admission have a poor prognosis. Data about STEMI complicated with CS and kidney function are sparse. We sought to assess the prognostic value of creatinine clearance on admission in patients with STEMI and CS treated with percutaneous coronary intervention (PCI). METHODS AND RESULTS: Between 1997 and 2005, a total of 3038 patients presented with STEMI and treated with PCI. On admission 292 patients presented with CS. Creatinine clearance (CrCl) could be calculated in 193 patients and classified in tertiles: group I > 96.8 ml/min; Group II between 67.5 and 96.8 ml/min; Group III < 67.5 ml/min. Overall one year mortality was 34%. In group I, II and III mortality was 24%, 30% and 45% respectively (P for trend 0.009). In multivariate logistic regression analysis, the odds for mortality increased with 96% for each tertile of admission CrCl (OR 1.961, 95%CI 1,135-3.385, P=0.016). CONCLUSION: Creatinine clearance on admission is strongly associated with one year mortality in STEMI patients with CS on admission and treated with PCI.