Overview of Vascular Disease

Background

Vascular diseases are a heterogeneous group of conditions involving arteries, veins, and lymphatic vessels. Collectively, they represent one of the leading causes of death and disability worldwide. According to the Global Burden of Disease (GBD) study, ischemic heart disease and stroke remain the top two causes of mortality, while peripheral artery disease (PAD), aneurysmal disease, and venous thromboembolism (VTE) contribute to major morbidity ^[1],[2].

The prevalence of vascular diseases is rising with population aging, increased prevalence of diabetes mellitus, hypertension, obesity, and smoking ^[3],[4]. In high-income countries, improved survival after myocardial infarction and stroke has also resulted in more patients living with chronic vascular conditions. In low- and middle-income countries, the burden is shifting rapidly, often without adequate access to specialized care.

Epidemiological studies, such as those from Fowkes et al. on PAD ^[4], and registries like Swedvasc and Vascunet, demonstrate that vascular disease is not only common but also associated with high long-term mortality and limb loss. Contemporary guidelines from the European Society for Vascular Surgery (ESVS) and Society for Vascular Surgery (SVS) emphasize integrated management — prevention, early diagnosis, and individualized treatment plans ^[5],[6].

Arterial Disease

Atherosclerosis is the predominant etiology of arterial disease. It results from a complex interplay between endothelial dysfunction, lipid deposition, chronic inflammation, and thrombosis. Established risk factors include:

• Modifiable: smoking, hypertension, diabetes, dyslipidemia, obesity, sedentary lifestyle.
• Non-modifiable: age, sex, family history, genetic disorders.

Inflammatory mediators (interleukin-6, C-reactive protein) and lipid abnormalities (high LDL, low HDL) play central roles ^[7].

Aneurysmal Disease

Abdominal aortic aneurysm (AAA), thoracic aortic aneurysm (TAA), and peripheral aneurysms (popliteal, visceral) develop due to degeneration of vascular wall connective tissue. Smoking is the most consistent risk factor for AAA, conferring a 5-fold increased risk ^[8]. Familial clustering suggests genetic predisposition. Connective tissue disorders such as Marfan and Ehlers-Danlos syndromes are strongly associated with TAA and dissection ^[9].

> See Also: 4Ch. 4: Aneurysmal Diseases for detailed management of AAA, TAA, and peripheral aneurysms.

Thromboembolic Disease

Virchow's triad — endothelial injury, venous stasis, and hypercoagulability — remains the conceptual framework ^[10].

• Acquired risks: trauma, surgery, malignancy, immobility, oral contraceptives, pregnancy.
• Inherited thrombophilia: Factor V Leiden, prothrombin gene mutation, protein C/S deficiency.

> See Also: 12Ch. 12: Venous Thromboembolism for comprehensive VTE prevention, diagnosis, and treatment.

Venous Disease

Chronic venous disease (CVD) often follows prior DVT with valvular destruction and reflux. Congenital venous malformations and primary valvular incompetence also contribute. Venous hypertension leads to edema, pigmentation, lipodermatosclerosis, and ulceration ^[11].

Table 1.1. Major Risk Factors for Vascular Disease

Use CEAP for standardized reporting (C1–C6 with etiologic, anatomic, pathophysiologic domains) and VCSS for severity. Post-thrombotic syndrome and primary valvular reflux share a final common pathway of venous hypertension leading to skin changes and ulceration ^[12],[13].

> See Also: 13Ch. 13: Chronic Venous Insufficiency for detailed venous disease management including CEAP classification applications.

Atherosclerosis

Endothelial dysfunction allows LDL to penetrate the intima, where it undergoes oxidation. Monocytes adhere, migrate, and differentiate into macrophages, forming foam cells. Smooth muscle proliferation and extracellular matrix deposition lead to fibrous cap formation. Plaque rupture triggers platelet activation and thrombus formation, which can result in acute ischemic events ^[7].

Aneurysm Formation

Aneurysmal disease is mediated by proteolytic degradation of elastin and collagen in the aortic wall, upregulation of matrix metalloproteinases, chronic inflammation, and biomechanical stress. AAA is associated with infiltration of T cells and macrophages, while TAA often relates to genetic mutations affecting connective tissue proteins such as fibrillin ^[8].

Thrombosis

Arterial thrombosis is platelet-driven, while venous thrombosis is fibrin-rich. Both involve the coagulation cascade and interplay between clotting factors and endothelium. Pulmonary embolism arises from embolization of venous thrombi ^[10].

Venous Insufficiency

Venous reflux increases hydrostatic pressure, leading to capillary leak, leukocyte trapping, inflammation, and tissue damage. This cascade underlies chronic venous ulcers ^[11].

Diagnostics and Imaging

Diagnosis integrates history, physical examination, hemodynamic testing, and imaging.

Clinical Assessment

History of claudication, rest pain, ulceration, or embolic events is essential. On examination:

• Arterial: pulse deficit, bruits, trophic skin changes.
• Venous: varicosities, edema, skin pigmentation, ulceration.
• Lymphatic: swelling, non-pitting edema, skin thickening.

For PAD, risk-stratify limb threat with WIfI staging (wound, ischemia, infection) and integrate with patient risk and anatomy (PLAN) to guide revascularization strategy ^[14].

Perioperative Cardiac Risk Assessment

Vascular surgery patients have high rates of coronary artery disease. The Revised Cardiac Risk Index (RCRI) helps stratify perioperative major adverse cardiac events (MACE) risk before non-cardiac surgery ^[15]. Vascular procedures (especially aortic and lower extremity) are classified as high-risk surgery, contributing 1 point to the RCRI score.

Hemodynamic Testing

• ABI: Sensitivity ~80%, specificity ~95% for PAD ^[16]. Limitations: falsely elevated in calcified arteries.
• TBI: Useful in diabetics and renal disease patients with calcification ^[17].
• TcPO₂: Values <30 mmHg indicate severe ischemia with poor wound-healing potential; 30–39 mmHg suggests moderate ischemia; ≥40 mmHg indicates adequate perfusion ^[18].
• Segmental pressures and plethysmography: Localize stenoses and assess venous reflux.

In CLTI, toe pressure <30 mmHg or TcPO₂ <30 mmHg indicates severe ischemia and poor wound-healing potential; WIfI staging integrates hemodynamics (toe pressure, TcPO₂), wound characteristics, and infection severity to stratify limb threat and guide revascularization ^[14]. See 10Ch. 10 for complete WIfI classification.

Imaging Modalities

• Duplex Ultrasound (DUS): First-line for PAD, AAA, carotid stenosis, venous reflux, and DVT. Operator-dependent but safe and inexpensive ^[19].
• CTA: Provides high-resolution 3D reconstructions for aneurysms and PAD; requires contrast and radiation ^[20].
• MRA: Useful when CTA contraindicated; gadolinium-based contrast or time-of-flight techniques ^[21].
• Catheter angiography: Remains the gold standard; allows simultaneous diagnosis and treatment but carries procedural risk ^[22].
• IVUS/OCT: Provide intraluminal detail; OCT superior for plaque characterization, IVUS for stent sizing ^[23].
• PET/CT: Detects active inflammation in aneurysm walls and vulnerable plaques ^[24].

Medical Management

• Lifestyle modification: Smoking cessation reduces AAA expansion and PAD progression ^[25]. Exercise therapy improves walking distance in PAD.
• Antiplatelet therapy: Aspirin or clopidogrel for secondary prevention in symptomatic atherosclerotic disease ^[26].
• Anticoagulation: Low-dose rivaroxaban plus aspirin benefits select PAD patients; see 10Ch. 10 for COMPASS/VOYAGER-PAD evidence and patient selection criteria.
• Lipid lowering: High-intensity statins reduce events and slow aneurysm growth. PCSK9 inhibitors provide additional risk reduction in statin-intolerant or high-risk patients ^[27].
• Blood pressure and glycemic control: ACE inhibitors and tight glycemic control improve vascular outcomes ^[28].

Open Surgery

• Bypass grafting: Autologous vein remains gold standard for infrainguinal bypass ^[29]. See 10Ch. 10 for BEST-CLI/BASIL evidence.
• CEA: Standard for symptomatic carotid stenosis >50% and select asymptomatic stenosis >70%. See 7Ch. 7 for NASCET, CREST, and patient selection.
• Open AAA repair: Durable long-term results, particularly for young/fit patients ^[30]. See 4Ch. 4.
• Thrombectomy/Embolectomy: Fogarty embolectomy remains the standard for acute embolic occlusion ^[10].

> See Also: Disease-specific surgical details: 4Ch. 4, 7Ch. 7, 10Ch. 10.

Endovascular Therapy

• PTA: Widely used for focal lesions, especially in iliac arteries.
• Drug-coated devices (DCB/DES): Improve patency in femoropopliteal disease; see 10Ch. 10 for evidence and paclitaxel safety considerations.
• EVAR/TEVAR: Reduced perioperative mortality compared to open repair; see 4Ch. 4 for RCT evidence and patient selection.
• Thrombectomy: Penumbra Indigo and AngioJet systems effective in acute limb ischemia ^[31].
• Embolization: Indicated for visceral aneurysms, endoleaks, hemorrhage.

> See Also: Disease-specific techniques: 4Ch. 4, 10Ch. 10, 16Ch. 16.

Hybrid Approaches

Combine open and endovascular methods, e.g., iliac stenting + femoral TEA or visceral debranching + TEVAR, offering flexibility for complex anatomy ^[32].

Table 1.2. Comparison of Treatment Options

Follow-up

Surveillance ensures early detection of complications such as graft stenosis, endoleaks, and restenosis.

• EVAR: CTA or DUS at 1 month, 12 months, then annually (ESVS, SVS) ^[33].
• Open AAA repair: Imaging only if symptomatic.
• Bypass grafting: DUS at 1–3, 6, 12 months, then annually ^[34].
• Carotid (CEA/CAS): DUS at 6 months, then every 1–2 years ^[35].
• Venous intervention: DUS at 1–3 months, then as clinically indicated.

For EVAR, risk-stratified surveillance per ESVS AAA guidance suggests that many standard EVARs may transition to duplex-based annual follow-up after a stable first-year scan, while complex anatomies or endoleaks require individualized schedules ^[36],[37].

Surveillance Intervals

Table 1.3. Recommended Surveillance Intervals by Procedure

Carotid surveillance per 7Ch. 7: DUS at 1, 6, and 12 months, then annually; adjust based on residual stenosis, periprocedural complications, or contralateral disease ^[38].

Foundational vascular anatomy and hemodynamics

The vascular system is organized into distinct anatomic territories, each with characteristic arterial, venous, and lymphatic components. Arterial anatomy includes the cervical and cerebrovascular territories, the thoracic aorta with its arch zones (0–3), the visceral and mesenteric circulation, the iliofemoral system, and the below-knee angiosomes. Key collateral networks include the circle of Willis for cerebral perfusion, the marginal artery of Drummond and arc of Riolan for mesenteric collateralization, and the genicular network around the knee.

Venous anatomy comprises the deep, superficial, and perforator systems, with the calf-muscle pump playing a central role in venous return. The lymphatic channels parallel the vascular tree and drain into regional lymph nodes.

Angiosome-directed revascularization refers to restoring blood flow to specific tissue zones based on direct arterial supply. In chronic limb-threatening ischemia (CLTI), this approach may improve wound healing outcomes, though evidence remains evolving ^[14]. Standard vascular nomenclature includes aortic arch zones (0–3), femoropopliteal segments, and named tibial vessels (anterior tibial, posterior tibial, and peroneal arteries).