Peripheral Arterial Disease: Who has it and what to do about it? Seth Krauss, M.D. Alaska Annual Nurse Practitioner Conference September 16, 2011
Scope of the Problem Incidence: <5% before age 65 >20% at age 75 1 15% after 55 In patients with established PVD, cardiovascular mortality is significantly increased 2 > 50% prevalence of concomitant CAD 1 Circulation 1985; 71: 510 2 NEJM 1992; 326: 381
Overview 1. Scope of peripheral arterial disease 2. Diagnosis and management of: Lower extremity occlusive disease Renal artery stenosis
Peripheral arterial disease (PAD): definitions Classic: non-coronary vascular disease, usually atherosclerotic Proposed: a. Visceral (renal, coronary, cerebral) b. Extremity Once established, atherosclerosis is without organ boundary
The Ankle-Brachial Index (ABI) ABI measurement is the optimal method to detect PAD Inexpensive, accurate, and office-based Provides an international standard, validated by angiographic detection, for defining PAD prevalence Predicts limb survival, propensity for wound healing, and short- and long-term patient survival 1,2 When is an ABI measurement indicated? Presence or suspicion of claudication; pain at rest; or nonhealing foot ulcer Age >70 years or >50 years with risk factors (diabetes, smoking) 1 McKenna et al. Atherosclerosis. 1991;87:119-128. 2 Newman et al. JAMA. 1993;270:487-489.
How to Perform and Calculate the ABI PARTNERS Program ABI Interpretation Right Arm Pressure: Left Arm Pressure: Above 0.90 Normal 0.71-0.90 Mild Obstruction 0.41-0.70 Moderate Obstruction 0.00-0.40 Severe Obstruction New Criteria 1.10-1.4 Normal 1.0-1.09 Low Normal 0.90-0.99 Borderline Abnl Pressure: PT DP Right ABI Left ABI Higher Right Ankle Pressure = mm Hg Higher Left Ankle Pressure mm Hg = = = Higher Arm Pressure mm Hg Higher Arm Pressure mm Hg 92 164 Example Higher Ankle Pressure = mm Hg Higher Brachial Pressure mm Hg Pressure: PT DP = 0.56 See ABI Chart
ABI: Limitations Possible false negatives in patients with noncompressible arteries, such as elderly and diabetic individuals ABI NEW NORMAL 1.1-1.39 BORDERLINE ABNL 0.91-0.99 LOW NORMAL 1.0-1.09 Insensitive to very mild occlusive disease or iliac occlusive disease Poor correlation with functional status in patients with claudication, therefore should be used in conjunction with standardized patient questionnaires to assess PAD severity
10 year all-cause mortality in PAD patients 100 75 Normal Asymptomatic PAD 50 Symptomatic PAD 25 Severely symptomatic PAD 0 0 2 4 6 8 10 year
Patients (%) Mortality in Patients With Severe PAD Relative 5-Year Mortality 100 80 60 38 44 48 40 15 20 0 Breast Cancer 2 Colon/Rectal Cancer 2 PAD 1 Non- Hodgkin s Lymphoma 2 1 McKenna M et al. Atherosclerosis. 1991;87:119-128. 2 Ries LAG et al. SEER Cancer Statistics Review, 1973-1997. National Cancer Institute.
34 Atherosclerotic Diseases in the PARTNERS Study Population PARTNERS provided an opportunity to compare data between four relevant community-derived populations Peripheral arterial disease only Cardiovascular disease* only Peripheral arterial disease and cardiovascular disease Healthy Adults No evident atherosclerosis PAD-/CVD+ PAD+/CVD+ PAD+/CVD- PAD-/CVD- *Cardiovascular disease defined as individuals with clinical evidence of coronary artery or cerebral arterial atherosclerotic syndromes.
36 Inclusion and Exclusion Criteria Targeted populations with atherosclerotic risk factors Age (>70 years) Younger individuals (50-69 years) with risk factors (smoking, diabetes) Geographically diverse sample Study centers in major urban regions of the US Initial Target Sample Size Goal: 1,500 PAD subjects by screening 10,000 at risk individuals
WIQ Score WIQ Score WIQ Score WIQ Measures of Walking Distance and Speed Across Diagnostic Groups 100 80 PAD+/CVD- PAD-/CVD+ PAD+/CVD+ PAD-/CVD- 60 40 20 0 n=313 n=376 n=205 n=1,168 n=339 n=383 n=207 n=1,201 Walking Distance Walking Speed PARTNERS Preliminary Data Report. 44
% Physicians Aware of PAD Physician Awareness of PAD by Individual Patient PAD/CVD Status 100 Reportedly Aware of PAD Reportedly Unaware of PAD 80 71.3% 77.2% 60 61.9% 40 20 28.7% 22.8% 38.1% *P<.001 0 n=564 All With PAD n=346 With PAD Only* n=218 With PAD & CVD* PARTNERS Preliminary Data Report. 48
% MD Awareness % MD Awareness Physician Awareness of PAD Smoking and diabetes >70 years 50 46.2% 40 30 20 10 35.8% 28.0% 29.3% 23.0% 35.4% 0 All With PAD With PAD Only With PAD & CVD PARTNERS Preliminary Data Report. 49
% Subjects % Subjects Patient Awareness of PAD by PAD/CVD Status 100 Reportedly Aware of PAD Reportedly Unaware of PAD 80 60 40 48.8% 51.2% 42.8% 57.2% 58.3% 41.7% 20 0 n=564 All With PAD n=346 With PAD Only* n=218 With PAD & CVD* *P<.001. PARTNERS Preliminary Data Report. 50
Lower-extremity: symptom generation asymptomatic claudication 1-level rest-pain limb-threat 2-level Iliac (in-flow) Superficial femoral artery (outflow) Popliteal Tibioperoneal (run-off)
Claudication - Natural History Symptoms remain stable or improve with time in 65% - 70% of patients due to development of collateral vessels. < 25% ever need surgery or angioplasty. Low risk of losing a limb - only 1.4% per year progress to critical life-threatening ischemia (however, patients with diabetes have an increased overall amputation risk of 20%).
Lower-extremity ischemia: Medical therapeutics Risk factor modification Exercise Supervised; 6 mos. Tobacco cessation Cilostazol PDE-III inhibitor 1-2 month trial drug interaction L-arginine
Lower-extremity ischemia: therapeutics Endovascular Stents: Improved iliac patency/durability c/w angioplasty Below inguinal ligament application less clear, but suggestive Stent-grafts: Attempt at improving restenosis rates, aneurysmal disease Total occlusion devices: Attempt to improve success in long occlusions in iliac/sfa Angiogenesis: IM injection of VEGF resulting in increased collateral flow Radiation: PARIS trial using gamma radiation
Lower-extremity ischemia: therapeutics
Femoropopliteal Disease Surgical Option Indicated for severe lifestyle-limiting claudication and long occlusions. 5 year patency rate for vein grafts Graft Type Fem-pop Tibial autologous 75% 67% synthetic 50% 14%
Femoropopliteal Disease Surgical Option operative mortality 1.7-3.5% operative morbidity 10% hospital stay 4-7 days resumption of full activity 4 weeks need for CABG?
Infrainguinal Disease: Ideal Candidates Surgery Clinical < 70 year old Non-diabetic Anatomic Single segment with intact run-off Long SFA stenosis Multi-segment disease with intact run-off Lesions Causing Atheroembolism Percutaneous Clinical non-diabetic, absence of gangrene Anatomic Short Non-calcified Non total occlusion Run-off intact Adjacent Aneurysmal Segment Bail-out
Lower-extremity Indications for revascularization are evolving 1-level 2-level asymptomatic claudication rest-pain limb-threat
Renal artery stenosis When did you last make the diagnosis?
Renovascular disease: incidence 1%-5% in general, but more in selected populations: Iliofemoral arterial disease: 30%-40% Carotid disease: 20%-30% Coronary artery disease: 20%-30% Congestive heart failure: 30% ESRD: 20% 80% atherosclerotic/20% fibromuscular dysplasia In general, the severity of associated atherosclerotic disease correlates with renal artery stenosis severity
Renovascular disease: Hypertension pathophysiology Renal parenchymal hypoperfusion with activation of the renin-angiotensin-aldosterone system Vasoconstriction Aldosterone-mediated volume expansion Endothelial dysfunction (chronic changes) Modulated by contralateral kidney naturesis and ipsilateral capsular collaterals Renal insufficiency Ipsilateral chronic hypoperfusion and progressive ischemic nephropathy Contralateral hypertensive arteriolar nephrosclerosis with Hyperfiltration Cholesterol/atheromatous embolization
Renovascular disease: natural history Progressive disease Baseline severity predicts progression: Normal~5%/year <60% stenosis~10%/year >60% stenosis~15%/year Occlusion: ~3%-5%/year Worse in high-grade lesions, diabetics Independent predictor of mortality 10% excess 5 and 10 year mortality in patients with hypertension and RAS
Renovascular disease: predictors Onset of hypertension <25 or >55 years old Recent or abrupt onset, or worsening/resistant hypertension (> 2 medications) Unexplained azotemia Abdominal bruit ACEI-induced renal dysfunction (bilateral RAS) Recurrent pulmonary edema and hypertension Marked difference in renal size Diabetes
Renovascular disease: evaluation Non-invasive testing for at-risk patients: No non-invasive gold-standard Characterized as functional (renin-angiotensin axis) anatomic (imaging/hemodynamic data)
Renovascular disease:anatomic testing Doppler ultrasound Operator dependent/~80% technically feasible Sensitivity~90% Specificity~95% High negative/positive predictive value, except in patients with accessory renal arteries (20%-30% incidence) Graded 0%, <60%, >60% stenosis MR angiogram Gadolinium enhancement improves imaging Some patients cannot be tested Expensive CT angiogram Contrast exposure Expensive
Renovascular disease:medical therapy In unilateral disease, ACEI and ARB s are safe and effective Beta-blockers are also effective Medications usually effective in controlling hypertension associated with RAS However, renal size and GFR continue to decrease even with good hypertensive control Compared with surgery, long-term mortality with medical therapy is worse
Renovascular disease:percutaneous Rx Angioplasty alone Limited by suboptimal acute (<80%) and long-term success rates (restenosis 20%-25%) Stent Good acute (>95%)and long-term (~85%) success rates Complication rate of 5%-10% Hemorrhage, embolism, renal failure Mortality~1% Efficacy Improved hypertension in 2/3 (cure 10%) Stabilized or improved renal function in 2/3 No randomized trial data available Improved CHF and coronary ischemia control
LE PAD Common PAD: Summary Marker for IHD, Cerebrovascular Dz correlate for ischemic burden Under Diagnosed PARTNERS ABI powerful prognostic cardiovascular test Treatment Serial study if ABI 0.90-1.09 Goals to increase functionality & quality of life Secondary prevention
PAD: Summary Renal Renal Artery Stenosis Consider in Refractory Hypertensive patient Worsening renal function Renal assymetry Recurrent CHF Screen with Renal Duplex Selective intervention HTN Ischemic nephropathy CHF