Aortic Stenosis

Q&A on Aortic Stenosis for Medical Students and Residents

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1. What is aortic stenosis (AS)?

• Medical Student Perspective:
  • AS occurs with aging, leading to calcification of the aortic valve.
  • Classic auscultatory finding: crescendo-decrescendo murmur, loudest at the right upper sternal border.
  • The most commonly encountered murmur in clinical practice.

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2. What physical exam findings suggest severe AS?

• Key Findings:
  • Late-peaking murmur
  • Diminished S2
  • Pulsus parvus et tardus (delayed and weak pulse).

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3. Does the loudness of the murmur correlate with AS severity?

• Answer: No. Murmur loudness does not reliably indicate severity.

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4. How are murmurs graded?

• Grades 1-6:
  • Grade 1: Faint, softer than S1/S2.
  • Grade 2: Equal in intensity to S1/S2.
  • Grade 3: Louder than S1/S2.
  • Grade 4: Associated with a palpable thrill.
  • Grade 5-6: Heard with the stethoscope barely or off the chest.

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5. What are the cardinal symptoms of AS?

• Symptoms & Mortality (Without Intervention):
  • Angina: 5-year survival.
  • Syncope: 3-year survival.
  • Heart failure: 2-year survival.

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6. How is AS severity determined via echocardiography?

• Severe AS Parameters:
  • Peak velocity > 4 m/s.
  • Mean gradient > 40 mmHg.
  • Aortic valve area < 1 cm².

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7. What are the stages of AS and when to consider intervention?

• Stages:
  • D1: Symptomatic severe AS; requires surgical (SAVR) or transcatheter (TAVR) valve replacement.
  • D2: Low-flow, low-gradient AS with reduced ejection fraction (EF). Confirm severity with a dobutamine stress echocardiogram.
  • D3: Paradoxical low-flow, low-gradient AS with preserved EF, often in elderly or small-framed patients. Still qualifies for valve replacement.
• Symptomatic patients: Always Stage D, warranting intervention.

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8. What is the difference between pseudo and true severe AS?

• Dobutamine Stress Echo Findings:
  • Pseudo-severe: Increased valve area (>1 cm²) and reduced gradient (<30-40 mmHg).
  • True severe: Valve area remains <1 cm², gradient increases >40 mmHg.

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9. What are the risks of TAVR (transcatheter aortic valve replacement)?

• Lower bleeding risk but higher:
  • Need for pacemaker.
  • Paravalvular regurgitation.
  • Risk of stroke due to embolization.

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10. What are the post-TAVR management priorities?

• Monitor for:
  • Stroke (due to emboli).
  • High-grade AV block.
  • Access site complications and distal pulse integrity.
• Routine evaluations:
  • Chest X-ray.
  • ECG (for new conduction abnormalities).
  • Repeat echocardiogram.
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Q&A on the PARTNER Trials for Aortic Stenosis

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1. What are the PARTNER trials?

The PARTNER (Placement of Aortic Transcatheter Valve) trials were pivotal studies evaluating the safety and efficacy of transcatheter aortic valve replacement (TAVR) compared to surgical aortic valve replacement (SAVR) or medical therapy in various risk groups for severe aortic stenosis (AS).

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2. What were the key findings of each PARTNER trial?

1. PARTNER 1 (High and Prohibitive Risk):
   • Cohort A: Compared TAVR to SAVR in high-surgical-risk patients.
     • Outcome: TAVR was non-inferior to SAVR for 1-year all-cause mortality.
   • Cohort B: Compared TAVR to medical therapy in prohibitive-risk patients.
     • Outcome: TAVR significantly reduced mortality and improved quality of life compared to medical therapy.

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2. PARTNER 2 (Intermediate Risk):
   • Studied patients at intermediate surgical risk (STS score 4-8%).
   • Outcome: TAVR was non-inferior to SAVR for 2-year all-cause mortality and stroke.
   • Subgroup Analysis:
     • Transfemoral TAVR had superior outcomes compared to SAVR.
     • Transapical TAVR had outcomes similar to SAVR.

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3. PARTNER 3 (Low Risk):
   • Focused on low-surgical-risk patients (STS score <4%).
   • Outcome: TAVR was superior to SAVR for the composite endpoint of death, stroke, or rehospitalization at 1 year.
     • Absolute risk reduction of 6.6% in adverse events with TAVR.

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3. How do the PARTNER trials influence current practice?

• High-risk patients (PARTNER 1): TAVR is the preferred approach.
• Intermediate-risk patients (PARTNER 2): TAVR is recommended unless contraindicated.
• Low-risk patients (PARTNER 3): Guidelines are evolving, but TAVR is increasingly favored for older low-risk patients due to less invasiveness.
  • SAVR remains preferred for younger patients due to the durability of surgical valves.

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4. What were some key advantages and risks noted in the trials?

• Advantages of TAVR:

  • Less invasive, shorter recovery time.
  • Reduced rates of bleeding and acute kidney injury.
  • Improved early quality of life.

• Risks of TAVR:

  • Higher incidence of:
    • Need for a permanent pacemaker.
    • Paravalvular regurgitation.
    • Late structural valve degeneration in younger patients.

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5. What guidelines emerged from the PARTNER trials?

• Patients with STS score ≥4% (high/intermediate risk): TAVR is recommended as the first-line intervention.
• Patients with STS score <4% (low risk):
• Older patients: TAVR is often preferred based on PARTNER 3 findings.
• Younger patients: SAVR remains preferred due to valve durability concerns and potential for future interventions.

Recommendations Clustering: SAVR vs. TAVR

When to Favor TAVR:

• High-risk (STS >8%): Proven in PARTNER 1.
• Prohibitive-risk: Superior to medical therapy (PARTNER 1, Cohort B).
• Intermediate-risk (STS 4-8%): Transfemoral approach preferred; proven in PARTNER 2.
• Older low-risk patients (STS <4%): Supported by PARTNER 3.

When to Favor SAVR:

• Younger patients (<65 years): Durability of surgical valves makes SAVR preferable.
• Low-risk with long life expectancy: To allow future valve-in-valve interventions after SAVR.
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