Table 4 Potential mechanisms explaining the obesity paradox in TAVI based on adipose tissue parameters

Higher SAT Area/Volume

Better survival (HR 0.76–0.87)

• Energy reserves during physiological stress

• Reduced cardiac cachexia

• Metabolically "safer" fat storage location

• Potential endocrine benefits from subcutaneous adipokines

• Lowest quartile patients may benefit from nutritional intervention

• Consideration of pre-TAVI nutritional optimization

• SAT area may be useful addition to risk scores

Lower SAT/VAT Density

Better survival (HR 1.01–1.46)

• Lower density indicates less fibrosis and inflammation

• Healthier adipocyte function with larger cell size

• Reduced immune activation in adipose tissue

• Less ectopic fat deposition in other tissues

• Higher density adipose tissue may indicate metabolic syndrome

• Adipose tissue density could be a novel biomarker

• Potential target for anti-inflammatory interventions

VAT:SAT Ratio < 1

Better cardiovascular outcomes (HR 3.06)

• Metabolically healthier fat distribution with predominant subcutaneous fat

• Lower inflammatory cytokine production

• Reduced ectopic fat in heart and vessels

• Simple ratio could serve as an easily calculated prognostic marker

• Potential for body composition-guided personalized management

VAT Area

U-shaped relationship

• Too low: possible cachexia, insufficient energy reserves

• Too high: metabolic dysfunction, inflammation

• Optimal intermediate range may be protective

• Optimal VAT range may depend on BMI category

• Non-linear relationships require careful statistical modeling

• Different significance in obese vs. non-obese (Mancio)

Extreme BMI values

Worse outcomes

• Both cachexia and morbid obesity represent metabolic derangement

• Central adiposity distribution may be more important than BMI alone

• Personal fat threshold concept (genetically determined capacity)

• Suggests focus on body composition rather than BMI alone

• Potential for identifying "metabolically healthy obese" TAVI candidates

• Importance of considering frailty alongside adiposity

IMAT Index

Higher index related to longer hospital stay

• Intramuscular fat infiltration indicates poor muscle quality

• Marker of sarcopenia and frailty

• May impair post-procedural mobilization and recovery

• Could be used to identify patients needing enhanced rehabilitation

• Combined assessment with muscle metrics may improve risk prediction