Best Practices to Achieve Quality Pressure-Volume Loop Data in Large Animal Models
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The document outlines best practices for collecting pressure-volume (PV) loop data in large animal models, emphasizing accurate measurement techniques and the importance of proper equipment and calibration. It covers the use of various tools, anatomical considerations for catheter placement, and monitoring physiological parameters during procedures. The guidelines aim to enhance data reliability and reproducibility in cardiovascular research involving large animals.
Best Practices to Achieve Quality Pressure-Volume Loop Data in Large Animal Models
- 1. Best-Practices to Achieve Quality Pressure- Volume Loop Data in Large Animal Models Filip Konecny, DVM PhD Transonic Tim Hacker, PhD University of Wisconsin Andy Henton InsideScientific Sponsored by:
- 2. InsideScientific is an online educational environment designed for life science researchers. Our goal is to aid in the sharing and distribution of scientific information regarding innovative technologies, protocols, research tools and laboratory services.
- 3. Thank you to our event sponsor
- 4. Best-Practices for Successful PV Loop Data Collection in Large Animals Filip Konecny, DVM PhD Applications Scientist & Surgical Trainer Transonic Copyright 2015 Transonic & InsideScientific . All Rights Reserved.
- 5. THIS WEBINAR IS TO PRESENT A SERIES OF “LARGE ANIMAL BEST PRACTICES” THAT WILL EVOKE CONFIDENCE IN YOUR PV LOOP DATA WHILE YOU ARE COLLECTING IT. WHEN FOLLOWED, THE SANITY CHECKS PRESENTED WILL PREVENT THE MULTIDISCIPLINARY TEAM FROM COLLECTING INNACURATE DATA Webinar Objectives…
- 6. Permits the measurement of P-V relationships (longitudinally) at multiple time points over a long period of time capturing instant changes Allows for the determination of instantaneous PV relationships in the ventricles; both individually (LV or RV), or simultaneously (bi- ventricular) application good data reproducibility, no use of radiation, low initial price and maintenance Allows extrapolating central and peripheral hemodynamic responses reflecting its respective changes Value of PV Hemodynamics in Large Animal Models
- 7. Value of PV Hemodynamics in Large Animal Models For more info please see our PV Workbook, pages 2-4 Echocardio (TTE) Cardiac CT Cardiac MRI PV (admittance) Volumetry relies on geometric assumptions Volumetry relies on geometric assumptions Volumetry relies on geometric assumptions PV corrects geometric assumption live LOAD DEPENDENT LOAD DEPENDENT LOAD DEPENDENT LOAD DEPENDENT LOAD INDEPENDENT Ventricle Pressure not measured Ventricle Pressure not measured Ventricle Pressure not measured Ventricle Pressure measured/correlated with volume-live
- 8. Value of PV Hemodynamics in Large Animal Models Click to Download the workbook
- 9. Control unit of PV system with “Large Animal” license, connects to data acquisition system (DAQ) using supplied analog cable. Supplied HDMI cable connects the PV catheter to the control unit. Large Animal PV Tools & Equipment
- 10. Large Animal PV Tools & Equipment Hemochron Jr. Signature Plus in-vitro whole blood micro-coagulation system. Two valuable tools often omitted by researchers are an Arterial Blood Gas monitor, and Whole Blood Micro-Coagulation System. Arterial blood gas (ABG) using IRMA True Point cartridges For more info please see pg. 98-103 in workbook Download modifiable excel sheet
- 11. Variable Segment Length (VSL) Catheters Excitation rings (1 and 4) (1 and 5) (1 and 6) (1 and 7) VSL Segm. 4 VSL Segm. 3 VSL Segm. 2 VSL Segm. 1
- 12. VSL Recording Rings to Ventricle Size Size (OD) Shaft Length 5F 45 inches (114.3cm) Ventricle size 45-75mm 55-90 mm 5F -Pigtail (20, 30, 40, 50 mm) ring spacing 5F-Straight (50, 60, 70, 80 mm) ring spacing Example of two 5F PV catheters Pigtail-Aorta Straight-Apex Numbers correspond to recording rings VSL ring spacing is customizable
- 13. Data Accuracy Comes From Calibration • PV systems track SV, EF and Contractility. • Absolute Volume is mathematically calculated value. • The calculation is based on three calibration values that the researcher needs to be aware of: 1. Stroke Volume Calibration Factor 2. Blood Resistivity (Rho) 3. Heart Type (Muscle Electrical Property)
- 14. 1. Stroke Volume Calibration Factor When a specific catheter is connected to the control ADV unit a default SV value will be populated based on the size/ring configuration. However, it is recommended that scientists use one of the following options to determine the most accurate reference as possible… If no secondary SV reference can be made result to literature or use the catheter default. Flow Probe PA catheterEchocardiography Cardiac MRI
- 15. 2. Blood Resistivity-BR (Rho) Resistivity (or conductivity) is a property of the blood being measured. Default values for BR are entered in the ADV500 control unit that represent healthy non-modified mammalian blood at 37C. If your experiments involve changing blood properties (i.e. hemorrhagic shock models), make measurements manually to address both pre and post blood change states. In large Animals (Dog, Swine, MiniPig, Sheep and Cow), BR range is 1.4-1.6 Ωm Calibration probe touching meniscus of freshly drawn blood. Please note the position of the probe. Do not submerge.
- 16. 3. Heart Type (Muscle Electrical Property) • The ADV 500 uses the term “Muscle Properties” to describe the ability of the myocardium to conduct a constant AC current signal. • It is important to acknowledge this calibration parameter since it will impact how much tissue contribution is removed from the measured admittance signal. • We offer tool to measure and add as custom For more info please see pg. 32-34 The ADV500 offers 3 default options for Heart Type
- 17. Example: 72kg Swine Animal Phase Range Phase Amplitude Magnitude Range Magnitude Amplitude Swine large (>65kg) 1-3 degrees 1.5 degree 15-30 mS 4-6 mS Example of left ventricle PV data using 7F PV catheter with pigtail; electrode ring spacing: 50,60,70,80mm Insertion: RCA/Aorta Active Segment: VSL 3 Note: Channel 1 and 2 (ECG)
- 18. Suggested Reading… Large animal models of heart failure: a critical link in the translation of basic science to clinical practice. Admittance-based pressure-volume loops versus gold standard cardiac magnetic resonance imaging in a porcine model of myocardial infarction. Right Ventricular Energetics and Power in Pulmonary Regurgitation vs. Stenosis Using Four-Dimensional Phase-Contrast Magnetic Resonance Invasive surgery reduces infarct size and preserves cardiac function in a porcine model of myocardial infarction. Admittance-based pressure-volume loop measurements in a porcine model of chronic myocardial infarction.
- 19. Large Animal Left and Right Ventricular PV Loops Tim Hacker, PhD Director, Cardiovascular Physiology Core University of Wisconsin- Madison Copyright 2015 T. Hacker, Transonic & InsideScientific. All Rights Reserved.
- 20. A bit of background… • Developed 22 different cardiovascular animal models in animals from mice to primates • Measurement & imaging of structural and physiologic parameters in all models • Currently using PV loops: – to measure LV function in stem cell treated infarcted swine hearts – to measure RV function a dog model of pulmonary hypertension • Using the ADV500 system in large animals for 3 years and small animals for over 5
- 21. Our Tools & Equipment List 1. 0.035 J guide wires (several) 2. Guide catheters or long sheaths (9Fr) 3. 7 Fr VSL straight tip and pig tail catheters, 9 and 11 Fr sheaths 4. Swan-Ganz Catheter (thermodilution) to measure SV 5. Infusion pump for dobutamine 6. Patient monitor 7. Ventilator (intubate) 8. Percutaneous access kit (ultrasound) Tip: Get the largest balloon you can find for occlusions (24 mm)
- 22. How we choose the right catheter Approach: carotid, jugular, femoral, apical stab Ventricle: right or Left Heart Size: overall length and internal space Operator Preference: over the wire vs. pig tail What works for us: • LV carotid = 7Fr pig tail VSL (terminal) • LV femoral = 7Fr straight over the wire (survival) • RV jugular = 7Fr straight over the wire (survival or terminal) with long curved sheath.
- 23. Anesthesia Pre-anesthesia: Pigs: Xylazine 2mg/kg and Telazol 4 mg/kg IM Dogs: Morphine Sulfate 0.5 mg/kg and Acepromazine 0.5 mg/kg SQ Extra anesthesia: Propofol 2-40 mg/kg IV Procedure anesthesia: Isoflurane (2%) Tip: learn about use of anesthetics and their reported hemodynamic effects before PV experimentation
- 24. Catheter Insertion If Terminal -- Cut down of carotid or jugular If Survival -- Percutaneous femoral or jugular (ultrasound guidance) • 9-11 Fr sheaths (dilate up as needed to get the large sheaths in) • Right Ventricle, we use a 60cm long sheath with an ‘L’ shaped tip to deliver the catheter to junction of the SVC and the RA • We cover the catheter with a sleeve during insertion through the sheath’s diaphragm. • Percutanous access of femoral vein for Swan Ganz and balloon Tip: An experienced cardiologist is valuable to show you the ropes, but ultimately once in the vessels it is not overly difficult to place the catheters.
- 25. Percutaneous Access Instruments used for femoral vascular access via percutaneous Seldinger technique. • 18-gauge, 2 3/4-inch Seldinger needle, • introducer sheath (cannula), • 0.035-inch guide wire • Heparinized saline
- 26. Femoral vasculature access via percutaneous Seldinger technique. Needle is inserted into the arterial lumen to advance an 0.035-inch guide wire before the introduction of a 7F sheath (cannula). Percutaneous Access Tip: Color code your lines (Artery = Red)
- 27. Catheter insertion through percutaneous sheath Final sheath placed in vessel is at least 2F size to allow smooth introduction and withdrawal. Percutaneous methods can reduce procedure time and improve animal recovery. Tip: Ultrasound can be used to find vessels.
- 28. Catheter Placement 1. Swan Ganz, use pressures and fluoroscopy to guide 2. PV catheter use contrast to get road map 3. Fluoro to guide into heart -- run wire or sheath to desired location 4. Note number of segments in ventricle 5. Check PV loops and phase/pressure to refine location 6. Run occlusion balloon to above diaphragm but below heart apex Tip: Patience and a light touch are a key to proper placement. Tip: Rotate catheter to get pressure window away from cords/papillary
- 29. IVC Occlusion caudal Insert deflated Fogarty occlusion balloon catheter into the IVC through the percutaneous LFV access. The insertion port on the LFV access has to be at least 2F size bigger to allow smooth access of the balloon catheter. Tip: Place occlusion balloon just above the diaphragm and just below apex of heart.
- 30. Monitoring Physiology Measurement Dog (10-20 kg) Swine (25-50 kg) Temperature 99.5 - 102 F / 37.5 - 39.0 °C 100 - 102.5 F / 37.5 - 39.5 °C Respiration Rate 12 - 18 breaths/min 12 - 20 breaths/min Heart Rate 75 - 105 beats/min 85 - 115 beats/min EtCO2 35 - 45 mmHg 35 - 45 mmHg SpO2 93 - 100 % 93 - 100 %
- 31. Tip: vital signs monitoring is crucial for PV repeatability Tip: Body temp and hydration changes will affect heart rate and SV Tip: Check pressure & HR trends during long procedures to confirm stability Monitoring Physiology
- 32. Special Consideration – Maintaining Blood Volume • loss of 10 % total blood volume is tolerable (for PV) • loss of 20-25% will lead to shock (Final data not physiological) • good PV vascular technique will minimize blood loss • fluid loss due to dry air ventilation, fasting, etc. Species Blood Volume Blood Loss (10%) Blood Loss (20%) Dog (15kg) 86 ml/kg ~100ml ~200ml Swine (30 kg) 65 ml/kg ~200 ml ~400 ml Tip: Start IV at beginning of procedure (saline, “Ringers”)
- 33. Load-Dependent LV Baseline Values Measurement (units) Dog Swine Heart Rate (bpm) 75 - 105 85 - 115 Systolic Pressure (mmHg) 90 - 110 75 - 100 Diastolic Pressure (mmHg) 3 - 5 3 - 5 Phase (degrees) 2.5 - 5.0 2.5 - 4.0 Magnitude (mS) 9 - 15 8 - 14 Ejection Fraction (%) 60 - 70 45 - 55 Note : These values are typical for control animals with isoflurane
- 34. PV Loops Are Position Dependent • Get position close using x-ray • Use contrast to define spaces if needed, save a cine loop for later reference • LV Placement -- Long axis from AO to apex • Note number of segments in LV by x-ray • RV Placement -- Outflow track axis (tip at PA valve) Tip: Breathing movement can make a big difference in the quality of the loop.
- 35. Creating an IVC Occlusion IVC occlusion Admittance Catheter Tip: Use a dobutamine challenge (20mcg/kg/min) to further define changes between treatments • Suspend respiration • Inflate balloon quickly • Monitor loop quality • Deflate balloon • Repeat at least 3 times
- 37. IVC Occulsion: Dog LV
- 38. IVC Occulsion: Dog RV with PAH
- 39. Suggested Reading… Intravenous Followed by X-ray Fused with MRI-Guided Transendocardial Mesenchymal Stem Cell Injection Improves Contractility Reserve in a Swine Model of Myocardial Infarction. View additional publications from Dr. Tim Hacker
- 40. Thank You! For additional information on solutions for large animal PV loops and hemodynamic monitoring equipment please visit: http://transonic.com/