Septal ablation in Hypertrophic Cardiomyopathy

Charles KnightLondon Chest Hospital

Advanced Angioplasty 2003

Terminology

• Non-surgical septal reduction (NSSR)

• Percutaneous transluminal septal myocardial ablation (PTSMA)

• Transcoronary ablation of septal hypertrophy (TASH)

• Septal ablation

• Alcohol ablation

• HOCM ablation• Sigwart procedure

History1980’sPreliminary experiments by Ulrich Sigwart at Laussane•Temporary balloon occlusion of first septal artery•Injection of verapamil down first septal artery

June 1994First septal ablation by Ulrich Sigwart at Royal Brompton

1997Described as ‘profoundly aggressive’ with an ‘unacceptably high mortality and morbidity’ in NEJM*

*NEJM 1997;337:349

Myotomy-myectomy

Patient selection

• No evidence for effect on prognosis

• Majority of patients with HCM have no obstruction (~75%)

• Majority of patients with obstruction have symptoms responsive to medical therapy

• Those with obstruction and unresponsive symptoms can be treated with septal ablation or myotomy-myectomy

No effect on:

• Underlying pathology– Myocardial disarray

– Small coronary artery abnormalities

– Diastolic dysfunction

• Associated mitral valve abnormalities

• Risk of sudden death• Prognosis

Effect on:

• Outflow tract gradient• Symptoms

Procedure

• Temporary pacing wire

• Intermediate wire to S1

• OTW balloon inflated at origin of S1

• Wire removed, balloon inflated

• 3-5ml of absolute alcohol injected

• 5 minutes marination then balloon deflated

Septal Ablation - Published Reports

• Knight et al Circulation 1997;95:2075 18 patients • Faber et al Circulation 1998;98:2415 91 patients • Lakkis et al Circulation1998;98:1750 33 patients• Gietzen et al Eur Heart J 1999;20:1342 50 patients• Kim et al Am J Cardiol 1999;83:1220 20 patients• Qin et al J Am Coll Cardiol 2001;38:1994 25 patients

• Total 237 patients

• Gietzen et al Eur Heart J 1999;20:1342 37 patients

• Faber et al Heart 2000;83:326 25 patients

• Firoozi et al Eur Heart J 2002;23:1617 20 patients

• Shamin et al NEJM 2002 ;347:1326 64 patients

• Total 146 patients

Longer term (7-36 month follow-up)

Pre

Post

Effect on Outflow Gradient

• All reports:

– 65 mmHg pre

– 5 mmHg post

• Reduction in gradient sustained in long-term

Shamin et al N Engl J Med 2002;347:1326

Effect on Symptoms

• All reports show significant improvement – Mean NYHA class pre 2.85, post 1.3

• Maintained over longer-term

Effect on exercise

• 3 reports assessed peak O2 consumption (n=104)– 44% improvement

• 7 reports assessed exercise duration/watts (n=204)– 41% improvement

• Maintained at longer-term

Shamin et al N Engl J Med 2002;347:1326

Mortality

• Short-term: 5/303 deaths (1.7%)– 2 in patients with severe pulmonary disease– 1 pulmonary embolus (line-related DVT)– 1 sudden AV block day 4– 1 sudden out-of hospital (?AV block)

• Long-term: 1 further death (pancreatic carcinoma)

Heart-Block

• Overall rate is ~ 20% requiring PPM

• Ranges from 0-40%

• Incidence appears to be reducing (contrast echo)

• 10% of surgical patients require PPM

• Beneficial effects of procedure similar in paced/not paced patients*

*Shamin et al N Engl J Med 2002;347:1326

Arrhythmias

• Early VF in 1.6%

• No late arrhythmias reported

Late Ventricular Dilatation

Information from 134 patients(4 reports)

•4.2mm Pre•4.7mm Post

Shamin et al N Engl J Med 2002;347:1326

Comparison with Surgery

• No randomised studies

• Two recent non-randomised comparisons– St George’s Hospital– Cleveland Clinic

• Patients well matched but septal ablation patients older and more co-morbidity

Septal ablation

Surgery

Number 25 26

Age 63 48

Gradient 64 28 62 7

NYHA class

3.5 1.9 3.3 1.5

PPM 24% 8%

Hospital stay

5.6 days 8.1 days

Septal ablation

Surgery

Number 20 24

Age 49 38

Gradient 91 22 83 15

NYHA class

2.3 1.7 2.4 1.5

Peak O2 19% 40%

Cleveland Clinic St. George’s

Qin et al JACC 2001;38:1994 Firoozi et al Eur Heart J 2002;23:1617

Conclusions

• Still limited data

• Not profoundly aggressive

• Results similar to surgery

• Mortality and morbidity acceptable and similar to surgery

• Should be performed as part of a HCM service by experienced operators

• Patient selection of paramount importance