Preoperative Evaluation and Questions: AS, AR, or both? If AS, how severe? Aortic valve opening: moderate AS = 0.7–0.9 cm2; critical AS = < 0.5 cm2 (normal = 2.6–3.5 cm2) Ao valve gradient: severe = > 50 mmHg Concurrent CAD? CHF? Esophageal stricture? surgery? injury? varices? (placement of TEE) AS is the most common valve lesion in US. Most commonly due to congenital bicuspid valve. if Angina 5yr survival is 50%, if syncope or dyspnea 50% survival at 2-3yrs.
Risk: Mortality: 5%, if EF is reduced operative mortality may be as high as 21% [Jaffe RA: Anesthesiologist’s Manual of Surgical Procedures, 4th ed. LWW: Baltimore, 2009]
Induction/Airway: Aortic Stenosis Patients are very pre-load and atrial kick dependent. Slow careful induction of anesthesia. Maintain sinus rhythm. Arrhythmias caused by PA catheter placement can lead to severe hypotension, wait to “float” PAC until in OR with surgical team ready for emergent CPB.
Lines and Monitors: Standard ASA, A-line, PAC, TEE. Place external cardioversion pads prior to induction.
Mode of anesthesia: General Anesthesia.
Surgical Course: Typical cardiac sternal incision. If Redo sternotomy, re-opening sternum involves significant risk of injury to the Right Ventricle and rapid, massive blood loss. Have blood checked and ready prior to sternotomy. Exposure can be prolonged due to scarring. Lungs, Heart, and Chest Wall can be adherent and normal anatomy altered. Post-CPB, air must be vented from the LV prior to discontinuation of CPB and restoration of systemic circulation.
Intraoperative Goals and Events: Pre-CPB Maintain sinus rhythm. Avoid hypotension (hypertrophic LV at greater risk for ischemia w/ hypotension). Aortic Stenosis patients may have elevated systemic BP post-op because the LV is accostomed to pumping against the stenotic valve, which is now gone. Consider NTG, or Nitroprusside for HTN control.
EBL: 100-500ml, Redo Sternotomy may lose additional 500-1000ml.
Duration: 3hrs, additional 1-2hrs if Redo sternotomy.
Emergence: keep intubated/sedated in ICU overnight.
Post-Operative Concerns, Transport, Disposition: to ICU.
Evidence-Based Medicine: [Carabello BA, Circulation 105:1746-1750, 2002]