What is the newest classification system for aortic dissection, including details such as the DISSECT and TEM frameworks?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: September 21, 2026 • View editorial policy

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.

Ask Question

Newest Classification System for Aortic Dissection

The most contemporary classification system for aortic dissection is the SVS/STS zone-based anatomic classification proposed in 2020, which defines dissections by entry tear location and proximal/distal extent using subscript notation (e.g., A₉, B₃₉), providing granular anatomic detail essential for modern endovascular and hybrid surgical planning. 1

Evolution of Classification Systems

Traditional Systems Still in Use

The DeBakey and Stanford systems remain the most commonly used classifications:

  • Stanford Classification divides dissections into:

    • Type A: Any dissection involving the ascending aorta (regardless of tear origin)
    • Type B: Dissections not involving the ascending aorta 1

  • DeBakey Classification categorizes by tear origin and extent:

    • Type I: Tear in ascending aorta, extends to arch and descending aorta
    • Type II: Confined to ascending aorta only
    • Type III: Originates in descending thoracic aorta
      • IIIa: Confined to descending thoracic aorta
      • IIIb: Extends below diaphragm 1

2019 European Addition: Non-A-Non-B Category

The European Association for Cardio-Thoracic Surgery and European Society for Vascular Surgery added "non-A-non-B dissection" for patients whose proximal dissection flap begins in the aortic arch, addressing a gap in traditional classifications 1, 2.

The SVS/STS Zone-Based Classification (2020)

This is the most granular and contemporary system, defining dissections by:

Anatomic Notation System

  • Type A (A_D): Entry tear in zone 0 (ascending aorta), with subscript D indicating distal extent (e.g., A₉)
  • Type B (B_PD): Entry tear in zone 1 or beyond, with subscripts P and D denoting proximal and distal extent (e.g., B₃₉)
  • Type I (Indeterminate): Dissection begins in zone 0 but entry tear location unidentified, designated with I and distal extent subscript (e.g., I₉) 1, 3

Clinical Advantage: This system provides precise anatomic detail critical for endovascular planning, specifically identifying where to seal entry tears and which zones require coverage 3.

Temporal Classification (SVS/STS)

The most contemporary temporal system divides dissections into four phases to guide intervention timing:

  • Hyperacute: <24 hours
  • Acute: 2-7 days
  • Subacute: 8-30 days
  • Chronic: >30 days 1, 2

This replaces the older binary "acute" (<2 weeks) vs "chronic" (>2 weeks) system and improves prognostication for intervention timing 1.

The TEM Classification System

The Type-Entry-Malperfusion (TEM) classification is a newer framework that expands Stanford by adding:

Three Components:

  1. Type: A, B, or non-A-non-B
  2. Entry (E): Location of primary intimal tear
    • E1: Ascending aorta
    • E2: Aortic arch
    • E3: Descending aorta
  3. Malperfusion (M): Clinical complications
    • M0: No malperfusion
    • M1: Coronary/cardiac malperfusion
    • M2: Cerebral malperfusion
    • M3: Visceral/renal/peripheral malperfusion 4, 5, 6, 7

Clinical Utility: The TEM system helps anticipate surgical strategy and identify high-risk patients. Entry tear location (E1 vs E2 vs E3) correlates with extent of arch resection needed, while malperfusion categories predict mortality and complication rates 5, 7. Coronary malperfusion (M1) predicts need for coronary artery bypass grafting and root replacement, while M3+ patients show the most severe multiorgan complications 5.

The DISSECT Mnemonic (2013)

The DISSECT classification is a mnemonic-based approach evaluating six critical characteristics:

  • Duration of disease
  • Intimal tear location
  • Size of dissected aorta
  • Segmental extent
  • Extent of complications
  • Complications present
  • Thrombus in false lumen 8

Limitation: While comprehensive, this system has not been widely adopted in major guidelines compared to SVS/STS or TEM classifications.

Practical Implications for Clinical Decision-Making

Why the SVS/STS System Matters

The zone-based notation directly informs endovascular planning by specifying:

  • Exact landing zones for stent grafts
  • Proximal and distal seal zones
  • Branch vessel involvement requiring fenestrated/branched devices 3

Why TEM Classification Matters

Malperfusion status drives urgency and approach:

  • M1 (coronary): Requires immediate surgery with potential coronary intervention
  • M2 (cerebral): May require staged approach or adjunctive procedures
  • M3 (visceral): Predicts highest mortality (20% by day 2,25% by day 30 in Type B) and may benefit from endovascular fenestration 1, 5, 7

Critical Pitfall

Do not rely solely on Stanford A vs B for contemporary management. While Stanford classification determines surgical urgency (Type A = emergency surgery), it provides insufficient detail for:

  • Endovascular intervention planning
  • Risk stratification beyond anatomic location
  • Predicting specific complications 8, 4

Guideline Recommendations

The 2022 ACC/AHA guidelines endorse the SVS/STS zone-based classification as the most contemporary system for defining aortic dissection anatomy in granular detail, while acknowledging that Stanford and DeBakey systems remain widely used for rapid clinical communication 1. The 2024 ESC guidelines similarly recognize the zone-based approach with subscript notation for guiding treatment decisions 2.

References

8
Research

DISSECT: a new mnemonic-based approach to the categorization of aortic dissection.

European journal of vascular and endovascular surgery : the official journal of the European Society for Vascular Surgery, 2013

Related Questions

What is the appropriate medical management and surveillance strategy for a patient with an ectatic aortic root?
How should acute renal failure be managed in a patient with a Stanford type I (type A) aortic dissection and DeBakey type I?
What are the Stanford and DeBakey (Michael E. DeBakey) classifications?
Why does recurrent chest pain occur in acute aortic syndrome?
What is the appropriate empirical therapy for severe soft‑tissue infection in a diabetic patient?
What are the indications, dosing, contraindications, side effects, monitoring requirements, and alternative treatments for Pristiq (desvenlafaxine)?
Does bupropion extended-release (XL) 300 mg require a taper when discontinuing?
What is the appropriate low‑dose naltrexone regimen for treating joint pain in a teenage patient with hypermobility and a connective tissue disorder?
What is the evidence for the efficacy and safety of oral pregnenolone?
What is the appropriate dosing of oxycodone for a patient with a creatinine clearance of 18 mL/min?

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.