Clinical Experience With A Self-expandable Venous Cannula During Cardiopulmonary Bypass In Minimally Invasive Cardiac Surgery
Karel M. Van Praet, Gregor Richter, Simon Sündermann, Alexander Meyer, Christoph Starck, Christof Stamm, Matteo Montagner, Axel Unbehaun, Stephan Jacobs, Volkmar Falk, Jörg Kempfert.
German Heart Institute Berlin, Berlin, Germany.
Objective. Despite progress in instrumentation and exposure techniques, venous drainage often remains a problem with minimally invasive cardiac valve surgery (MICVS). Additionally, remote (femoral) cannulation-sites lead to the use of longer low-profile cannulas with limited drainage capacity. Consequently, we aim to report our experience with an expandable venous cannula. The concept is based on a self-expanding non-covered stent avoiding venous collapse. Methods. From 02/2017-10/2017 we performed MICVS using the smartcanula in 58 patients. Forty-four patients received mitral valve surgery through a right lateral minithoracotomy; 14 patients underwent surgical aortic valve replacement via a right anterolateral minithoracotomy approach. Insertion and positioning of this new cannula through the femoral vein (both open or fully percutaneous) was performed under strict TEE guidance. Results. Mean age and BSA was 61.81±13.81years and 1.92±0.23m˛ respectively. CPB-flow was pre-calculated on an index of 2.2L/min/m˛ and adjusted based on DO2 guidance at a body temperature of 34°C. Mean CPB-flow in "steady state" (X-clamping interval) was 3.95±0.56 L/min resulting in a cardiac-index of 2.13±0.48 L/min/m˛. Mean central-venous-oxygen-saturation (SvO2) and peak-lactate during CPB was 80±5.47% and 15.86±13.11 mg/dl indicating sufficient perfusion. Mean CPB- and X-clamping-time was 115.51±38.77 min and 68.46±22.4 min, respectively. Mean venous negative-drainage-pressure required during "steady state" was -27.56±0.56 mmHg, only. Subsequently, only limited mean platelet-drop (70.19±42.91K/µL), moderate LDH-rise (158.58±151.3U/L) and WBC rise (6.06±5.15K/µL) measured on postoperative day 1 was observed. During the postoperative course 1 minor stroke was observed. Two patients required re-thoracotomy for bleeding. Median Length of ICU -and hospital-stays were 1 [range; 1-10] days and 5 [range; 4-32] days. No in-hospital-mortality (0%) or acute renal failure (0%) was observed. Conclusions. Venous drainage via a single femoral self-expandable metallic stent venous cannula results in optimal venous drainage. This low-profile cannulation technique facilitates perfusion in minimally invasive cardiac valve surgery requiring low negative-drainage-pressures. Figure 1. A1-2) Stretched cannula mesh with a semirigid obturator, ready for low-profile insertion. A3) Cannula positioned in the right atrium and SVC (TEE) B1-2) Fully expanded configuration after obturator removal. B3) Tip of the expanded cannula reaching into the SVC.
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