83 page Arterial VASCULAR DISEASE Presentation on CD

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TITLE:Peripheral Vascular Disease:A closer look at lower extremity chronic arterial insufficiency, 83 pages (slides) 

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Peripheral Vascular Disease:A closer look at lower extremity chronic arterial insufficiency Rich Serianni, LCDR, MC, USN Objectives Understand lower extremity vascular disease – its presentation and treatment Understand associated comorbidities Review evidence surrounding best anesthetic technique Outline Epidemiology Pathophysiology Diagnosis/Treatment Modalities Develop an understanding of the patient population reaching the operating room. Anesthetic Management Comorbidities Factors surrounding choice of anesthetic technique – a review of evidence. Epidemiology 10 million people in the United States, mostly >50 years old 5% of men and 2.5% of women over 60 years old have symptoms of intermittent claudication. Prevalence of 4.6% in those 60-74 using questionnaire based studies. Prevalence 16% for men and 13% for women in studies using ABI<=0.9 Atherosclerosis Pathophysiology Formation of plaque centers around an inflammatory response Atherosclerosis Pathophysiology Inflammatory Response central to plaque formation Excess LDL in arterial wall undergo chemical alteration, stimulate endothelial cells to display adhesion molecules that latch on to monocytes and T cells Monocytes become macrophages producing cytokines and ingesting LDLs Fat-laden macrophages (foam cells) and T cells form the fatty streak (early plaque) Atherosclerosis Pathology Fatty streak of macrophages and T cells secrete inflammatory mediators promoting growth of plaque and formation of fibrous cap (smooth muscles cells of media migrate to intima). Cap increases size of plaque and walls it off from blood (most expand outward of blood flow) Inflammatory mileu from foam cells weakens cap by digesting matrix and damage smooth muscle - also display tissue factor a potent clot promoter. Weakened plaque ruptures, tissue factor interacts with blood causing thrombus, then ischemia. Risk Factors Hyperlipidemia (LDL spurs reaction) Diabetes (glucose enhance glycation and inflammatory properties of LDL) Obesity (contributes to diabetes and vascular inflammation) HTN (indirect affect but Angiotensin II may incite inflammation) Smoking (increases oxidants that can attack LDL) Diagnosis History & Physical Risk factors include smoking, HTN, HLD, diabetes, obesity, sedentary lifestyle, family history. Intermittent claudication most common symptom. Ankle Brachial Index common screening tool. Laboratory Screening Tests Cholesterol Panel C-reactive protein Ridker studied relative risk of different combinations of cholesterol and CRP. Avg cholesterol (3rd quintile) with highest CRP (5th quintile) same relative risk as those with highest cholesterol (5th quintile) and lowest CRP (1st quintile) Both 4.2 relative risk MORTALITY RISK All cause mortality at 5 years THREE times higher in patients with symptoms of intermittent claudication. 75% of this mortality from coronary or cerberovascular causes. 66% coronary 9% cerebrovascular Conservative Therapy Lifestyle modification Exercise Smoking cessation Antiplatelet Decreases platelet adhesion Reduces nonfatal MI by 30%, nonfatal stroke by 30%, death from all vascular causes by 16%. Statins Lower LDL and inflammation Medications approved for use in Intermittent Claudication Pentoxifylline (Trental) Methylxanthine derivative Decreased viscosity, platelet reactivity Cilostazol (Pletal) Phosphodiesterase III inhibitor More effective but more frequent side effects, contraindicated in CHF Natural History of Intermittent Claudication 50% no change or improvement in symptoms 16% symptoms progress 25% surgical intervention required <4% amputation Imaging Refractory Claudication Angiography Diagnostic and therapeutic capabilities MRA Less expensive Prone to artifacts (motion, clips, prothesis) Angioplasty Advantages: Faster recovery, shorter stay, local anesthesia Maintains saphenous veins for future use, can be repeated. Disadvantages: Lower patency rates Not useful in multi-level stenosis Bypass Surgery Advantages: Gold standard Good long-term patency, can use in multiple stenosis Disadvantages: Higher rate of morbidity Requires harvesting of conduit Endovascular Techniques Angioplasty Localized lesions <10cm in length Stents Intra-arterial thrombolytic therapy Success rates streptokinase 60%, Urokinase 5%, 91% rt-tPA. Complications bleeding, distal embolization. Operative Candidates Those reaching the operating room have failed to respond medical and angioplasty treatment and represent a distilled population with advanced atherosclerotic disease. Critical Leg Ischemia 15% of those with claudication Anesthetic Management Review Comorbidities Anesthetic Goals Epidural vs. General Anesthesia Anticoagulation and regional techniques Comorbidities Coronary Heart Disease (40-78%) HTN (60%) Cerebrovascular Disease (10%) Diabetes (10%) Krupski, et al. Goal Compare differences in perioperative cardiac ischemic events between major abdominal versus infrainguinal vascular operations Design Prospective, randomized Outcome Measures Cardiac death, nonfatal MI, unstable angina, CHF, Ventricular tachycardia Patient Selection 140 patients (all male) undergoing elective aortic or infrainguinal operative treatments. Excluded: patients with pacemakers, LBBB, esophageal disease, emergent cases. Preoperative Eval - Krupski All standard 12 lead EKG 1-3 days preop All continuous Holter monitor 48 hours prior to operation to POD 2 Dipyridamole thallium in 38 selected patients Intraoperative Measures - Krupski 12 lead EKG Holter monitor TEE with transgastric short axis mid papillary view Postoperative Measures - Krupski 12 lead EKG daily x 7 days, day 10, day 14, weekly thereafter until discharge. EKG if clinically indicated (CP/SOB) Continuous Holter monitor POD 1 and 2. CPK and LDH POD 1 and 5. Results – Perioperative Ischemia Preoperatively similar Intraoperatively similar by EKG, Holter but more ischemic episodes in aortic group Postoperatively more ischemia in infrainguinal, clinically silent Postoperative Ischemia Postoperative Cardiac Outcomes Infrainguinal revascularizations carry an equivalent risk for major adverse cardiac outcomes when compared to aortic operations Preoperative Predictive Values Only preoperative ischemia by Holter monitoring correlated, but >50% of outcomes occurred in patients without preoperative ischemia. Consider the Goals… Anesthetic Goals Myocardial Protection Optimize chances for long term success (can we influence the incidence of graft restenosis?) Myocardial Protection Risk for Perioperative MI is at least the same for those undergoing infrainguinal procedures as those patients undergoing aortic surgery. Restenosis Large Diameter vessels (femoral) 80-90% 5 year patency rate Infrapopliteal Saphenous conduit - 49% 4yr patency PFTE conduit - 12% 4yr patency Stenting Reduce relative risk of long term failure by 39% over PTA alone Brachytherapy Trials ongoing Anesthetic Management Does epidural anesthesia confer any advantages for myocardial protection and/or graft patency? Yeager, et. al Goal Evaluate effect of epidural anesthesia and postop analgesia on postop morbidity in group of high-risk surgical patients. Design Prospective, randomized Outcome measures - caregivers were blinded to outcome variables… Clinical Outcome Endocrine Response Cost Utilization Patient Selection - Yeager 53 patients >18yo 25 general, 28 epidural No contraindication to epidural Already scheduled for postop ICU Procedures Intrathoracic Intrabdominal Major vascular (noncerebral) Anesthetic Care - Yeager Epidural Group Epidural with bupivicaine (0.75% or Lidocaine (1.5%) with epi PLUS “Light” GETA with nitrous, O2, small dose narcotic and relaxant Intraop monitoring at discretion of anesthesiologist. GETA High dose narcotic (>35 ug/kg fentanyl if using nitrous OR >50 ug/kg fentanyl without nitrous) OR Balanced (<35 ug/kg fentanyl) with O2, nitrous or low conc (<1 MAC) volatile and relaxant Intraop monitoring at discretion of anesthesiologist. OUTCOME MEASURES - Yeager Mortality Major Morbidity CV Failure (transmural MI, nontransmural MI, recent MI at autopsy, CHF, cardiogenic shock, V tach, SVT requiring med tx, heart block) OUTCOME MEASURES - Yeager Endocrine Response Preop, intraop and first 2 POD urine free cortisol Preop,1 hour post incision and ICU arrival serum cortisol. OUTCOME MEASURES - Yeager COST Total anesthesia time Duration of postop intubation ICU stay Discharge and hospital costs Results – Morbidity/Mortality General anesthetic patients had statistically significant more mortality and morbidity Results – Endocrine Response Epidural patients had significantly reduced cortisol excretion for 24 hours postop. Results - Costs Epidural hospital costs and physician costs significantly less than general. Conclusions - Yeager When compared to controls, patients receiving epidural anesthesia and analgesia had: Reduction in overall postop complication (p=0.002) Reduction in incidence of cardiovascular failure (p=0.007) Reduction in incidence of major infectious complications (p=0.007) Diminished urinary cortisol excretion (stress response) in first 24 hrs postop (p=0.025). Lower hospital costs (p=0.02) Conclusions - Yeager “…patients who received EAA had reduced incidence of cardiovascular complications…but mechanisms involved were not defined in this study. We cannot ascribe the reduced cardiovascular morbidity to any single, specific effect of EAA…improved pain control, venodilation with fewer abnormal elevations of preload, lessened overall complication rate and other factors yet to be defined.” Epidural It is!! Bode, et al. Goal Impact of anesthetic choice on cardiac outcome in patients undergoing peripheral vascular surgery Design Prospective randomized of 705 consecutive patients Outcome Measures Cardiac morbidity outcomes of MI, angina, CHF Mortality as death during hospital stay Patient Selection 705 patients scheduled for elective fem-distal surgeries of which 433 randomly assigned to general, epidural or spinal anesthetic 282 of 705 excluded - contraindication to regional, prior lower back surgery, patient refusal, operations requiring arm veins. Outcome Measures - Bode Daily interviews and exams to look for evidence of angina and/or CHF Daily 12 lead EKG read by 2 cardiologists blinded to anesthesia received. CK isoenzymes q8hr x3, then daily x3 days Methods - Bode Spinal Anesthetic Hyperbaric tetracaine 1% (16-20mg) with 3-5mg phenylephrine at L4-5 or L3-4 in lat decub operative side down x 10 min. Epidural Anesthetic L2-3 or L3-4 with 2% lidocaine bolus and 0.5% bupivicaine maintenance titrated to T8-T10 dermatone. General Anesthetic preO2, Thiopental, fentanyl (1 mcg/kg) and Succ/Vec induction. Maintenance with fentanyl (20-50 mcg/hr) Iso or Enfl (0.5-1.5 MAC), nitrous (50-70%), NM Blockade, PPV. Methods - Bode All pts with preop 12 lead, monitoring included A-line, PA cath, pulse ox, EKG GETA pts also monitored with capnography, mass spec, nerve stimulator Intraop Mgmt NTG (0.5-1.5 mcg/kg/min) typically given thru 6-12 hr postop to aid in BP and PA pressure control - dosing to discretion of anesth team. Fluid therapy guided by PA, no protocol to dictate (approx 2L crystalloid) Methods - Bode Premedication IV midazolam and/or fentanyl. Postoperative Care ALL patients to PACU for 12-24 hrs, continuous EKG and PA monitors, pain relief IV morphine/meperidine. Some epidural MSO4. All epidurals removed on DC from PACU Absolute Risk Difference Conclusions - Bode Choice of anesthesia does not significantly influence cardiac morbidity and overall mortality in patients undergoing peripheral vascular surgery. Christopherson, et. al Goal Compare outcomes between epidural and general anesthesia in group of patients undergoing lower extremity arterial grafting for atherosclerotic PVD Design Prospective, randomized Outcome Measures Primary cardiac Secondary noncardiac Patient Selection 100 patients for elective LE reconstruction Excluded if involved aorta or iliac, coagulopathy, airway abnormality, LBBB, pacemaker, LVH Methods - Christopherson Preop - Holter monitor thru POD 3 Intraop All: EKG, pulse ox, A-line, continuous HR and BP strip Unstable angina, uncompensated CHF, pulm HTN, MI<3months = PA Cath Compensated CHF, MI within 6 months, oliguric renal failure = CVP Data Sources EKG (12 lead preop, DOS, POD 1,2,3) CK and MB q6hr in ICU then qd POPD 1,2,3,7 Any information on CP in first 7 postop days. Autopsy information Anesthetic Techniques Christopherson Epidural Fluid load 10cc/kg L2-3 or L3-4 with bupivicaine (0.75%) maintain T8 dermatone Fentanyl 25 mcg and midazolam 0.5mg premed/sedation End of case 100 mcg fentanyl via catheter GETA O2, Thiamylal (50 mg) and fentanyl (25-50 mcg) to unconsciousness. Succinylcholine Maintenance with 50% nitrous, 0.3-1% enflurane, pancuronium MSO4 titrated at end to RR 10-166, extubated MSO4 PCA postop Outcome Measures Christopherson Primary (by cardiologist blinded to anesthetic technique) Death within 6 months Major cardiac morbidity (cardiac death, nonfatal MI, unstable angina) Secondary Re-operation, respiratory failure, major infection, renal failure, ICU readmission Intraoperative Mgmt No significant differences HR maintained 40-85, pressor/anesthesia prn Fluids used to maintain PCWP/CVP between 8 above and 2 below baseline, UOP>0.5 cc/kg/hr, Hct>30 Postoperative Course Outcomes No statistically significant difference in primary outcome measures (cardiac) Significantly higher rate of re-operation for graft occlusion in patients receiving GETA. Conclusions - Christopherson Clinical recommendation of epidural vs. general anesthesia for myocardial protection cannot be made. Re-operation for inadequate tissue perfusion required more frequently in general anesthesia group, majority of which soon after surgery suggesting that anesthetic differences most pronounced in immediate postop period. Jury Still Out… Jury Still Out… Anticoagulation and Regional Techniques Anticoagulant Risks Many patients will require anticoagulant therapy in perioperative period. Bleeding major complication Incidence: Heparin (<3%) Coumadin INR>4 (7%) Thrombolytics (6-30%) Risk vs. Benefit of Regional Little data regarding peripheral blocks and anticoagulation – bleeding and not neurological injury most common reported complication Neuraxial techniques associated with spinal hematoma. Spinal Hematoma Spinal cord injuries leading cause of claims during the 1990s (ASA closed claims data) Incidence: 1 in 150,000 epidurals Less than 1 in 220,000 spinals Preoperative medical therapy for PVD patients.. Antiplatelet Aspirin: proven to delay progression, large Antiplatelet Trialist Collaboration of over 100,000 pts decrease in nonfatal MI, nonfatal stroke by 33%, death from all vascular causes by 1/6. Clopidogrel: irreversible, some evidence better than ASA decreasing incidence of MI, ischemic stroke, death from vasc causes ( incidence of 5.83% ASA vs. 5.32% Clodiprogel with p=0.043) Lower Extremity Bypass Procedures Perioperative Anticoagulants Heparin pre, intra and postop often used Warfarin often prescribed for graft patency Antiplatelet Agents NSAID No added risk Theinopyradine Derivatives (Ticlopidine, Clopidogrel) No published studies Ticlopidine wait 14 days Clopidogrel wait 7 days GP IIb/IIIa Inhibitors (abciximab, eptifibatide) Wait for normal platelet function to return Range 8 hours (eptifibatide, tirofiban) to 24/48 hours (abciximab) Heparin IV Heparin Delay administation for 1 hour post needle placement Remove catheter 2-4 after last dose Intraop heparinization not precluded LMWH Prophylactic vs. Therapeutic Placement 10-12 hrs after prophylactic dose, 24 hrs after last therapeutic Avoid in pts given any dose 2 hours preoperatively as this coincides with peak anticoagulant activity. Warfarin Affect II, VII, IX, X PT and INR sensitive to VII and X, VII shortest half-life INR>1.2 = VII 40% normal Initiation or warfarin INR<1.5 assoc with NORMAL hemostasis Recovery after DC of warfarin requires NORMAL INR since II and X activity recover slowly Caution in performing regional, DC warfarin 4-5 days before block, measure INR SUMMARY Claudication prevalent symptom in aging population and sign of significant underlying disease pathology. Failed conservative and endovascular therapies often distill the operative candidates to those with the most severe atherosclerotic disease Lower extremity bypass procedures are not without significant risk. 12% of fem-pop patients suffer cardiovascular event or death. (Bode), 12% MI or death (Christopherson) Ischemia (often silent) in infrainguinal patients: Intraop 10-26%; Postop 57% (Krupski) SUMMARY Preoperative evidence of ischemia increases risk but those without preoperative ischemia also at risk Monitoring a-line, PA and CVP No clear myocardial advantage to epidural, mixed data on restenosis but no worse outcomes…. My approach…Wizard not the Wand….. Approach as heart patient… Close attention to comorbidities.. A-line, CVP/PA as cardiac function warrants. Myocardial Preservation through supply and demand Epidural if no contraindication – no worse outcomes. Careful postoperative management. Questions??, Fire Away…