Medical Policies - Medicine
Transcoronary Ablation of Septal Hypertrophy (TASH)
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Transcoronary ablation of septal hypertrophy (TASH) may be considered medically necessary as a treatment of hypertrophic obstructive cardiomyopathy.
Hypertrophic cardiomyopathy is a complex cardiac disease associated with diverse clinical, morphologic, and pathophysiologic manifestations. However, one of the most characteristic abnormalities is a hypertrophied and nondilated left ventricle, which may impair diastolic filling. When the hypertrophy results in left ventricular outflow obstruction, dyspnea, angina, syncope, or the development of congestive heart failure may occur. Pharmacologic therapies include beta-blockers or calcium-channel blockers to decrease the heart rate with a consequent prolongation in diastole and increased passive ventricular filling. If medical therapy is insufficient to control symptoms, strategies to reduce the outflow obstruction may be considered. Surgical reaction focuses on removing a small amount of myocardium at the base of the septum (myotomy-myomectomy). Dual-chamber pacing has also been explored as a means of decreasing the pressure gradient in the outflow tract, although results of randomized trials have been disappointing.
Transcoronary ablation of septal hypertrophy (TASH) (also referred to as percutaneous transluminal septal myocardial ablation, alcohol [ethanol] septal ablation, and nonsurgical septal reduction therapy) (1) has been explored as an alternative to open surgical septal resection. The technique involves infusion of ethanol through an angioplasty catheter threaded into the septal perforator branches of the left anterior descending artery, to infarct and subsequently thins the bulging septum. A key component of the procedure is the identification of the target vessels. A balloon catheter is introduced into the septal branches. The balloon is inflated and contrast injected into the balloon lumen to delineate the area supplied by the septal branch and to ensure that the balloon inflation would prevent spillage of the subsequent injection of alcohol into the left anterior descending artery. Myocardial contrast echocardiography has also been used to target septal vessels. Echocardiographic contrast material may be injected into the balloon catheter and, using ultrasonography, the perfused area of the myocardium can be imaged from several different positions.
This policy was developed in May 1999 and was updated periodically with literature reviews through May 31, 2017. Following is a summary of the key literature to date.
Ventricular septal myotomy and/or myomectomy (also called the Morrow procedure) is considered the gold standard treatment for septal hypertrophy, based on case series that have consistently demonstrated both symptomatic and cardiodynamic improvement with an acceptable short-term mortality ranging from 2% to 5%. Patient selection criteria typically include those patients with severe outflow gradients (³50 mm Hg under basal conditions) and symptomatic heart failure (New York Heart Association [NYHA] Class III or IV) that is refractory to medical therapy. Ideally, controlled clinical trials comparing the short- and long-term outcomes of myotomy/myomectomy with transcoronary ablation of septal hypertrophy (TASH) are needed to validate the equivalency or superiority of TASH. No such studies are available, and the literature regarding TASH consists of case series with relatively short follow-up, predominantly from single institutions. Data regarding the short- and long-term outcomes of myotomy/myomectomy also consist of case series from single institutions; however, follow-up often exceeds 10 years. Unlike patients undergoing TASH, patients undergoing myotomy/myomectomy often undergo additional procedures, such as coronary artery bypass grafting, or mitral or aortic valve replacement. In many instances, patients undergoing myotomy/myomectomy were treated some 20 years ago, and it is likely that the morbidity and mortality has declined over the decades. In addition, all case series include patients of varying ages and with variable severity of disease, both of which may impact short- and long-term outcomes. Given these significant limitations in the available literature, the short- and long-term outcomes of myotomy/myomectomy and TASH are summarized below.
Ventricular Septal Myotomy and/or Myomectomy
The most recently published case series are reviewed here, focusing on the short-term outcomes for comparison purposes. In 1989, Mohr et al. summarized the outcomes of 115 patients who underwent myotomy/myomectomy between 1972 and 1987. (2) The outflow gradient was markedly reduced and 76%, 83%, and 96% of patients reported relief from dyspnea, angina, and syncope, respectively. Overall, the operative mortality was 5.2%, but only 1.2% in those less than 65 years old, rising to 15.6% in those older than 65 years. In addition, the operative mortality was 2.5% for those undergoing myotomy/myomectomy alone compared to 11.4% in those undergoing additional procedures. In 1996, Robbins and Stinson reported on a case series of 158 patients over a 22-year span. (3) The operative mortality was 3.2% for those over 60 years old and 0% for those under 60. Again, the operative mortality of those undergoing myomectomy alone was lower, at 2.3%, compared to 7.4% in those undergoing combined procedures. Similar to other studies, there were improvements in NYHA functional classes and cardiodynamic improvements. In 1998, Schönbeck et al. reported on a case series of 110 patients spanning 30 years. (4) The perioperative mortality rate was 3.6%. The left ventricular outflow tract gradient was nearly eliminated in all patients.
Clinical studies of TASH consistently report improvements in various signs and symptoms including NYHA classification, exercise time, left ventricular pressure gradient, and septal thickness as measured by echocardiography. The larger case series are reviewed here. Seggewiss et al. reported on a case series of 114 patients with symptomatic hypertrophic cardiomyopathy who underwent TASH. (5) Left ventricular outflow tract gradient was reduced in 94% of patients from a mean of 73.8 mm Hg to 18.6 mm Hg with the gradient further declining at the 3-month follow-up. The NYHA classification also improved, with all patients categorized as either NYHA Class l or II. A total of 11 (9.6%) patients required a permanent pacemaker due to trifascicular block and 2 patients (1.8%) died during the hospital stay. Kuhn et al. reported on a case series of 215 procedures in 187 patients. (6) The perioperative mortality rate was 2.3%. At a mean follow-up of 2.4 years, the NYHA classification had decreased from 3.0 to 1.6. Similar to the data reported by Seggewiss, there were significant improvements in cardiodynamic measures, including outflow gradient and septal thickness. Gietzen et al. reported on 62 patients undergoing TASH, all of whom had substantial clinical improvement. The procedure-related early mortality was 4%, and a permanent pacemaker was required in 40% of patients. (7) Lakkis et al. reported on the 1-year follow-up of 50 patients undergoing TASH. (8) A total of 16% of patients required permanent pacemaker implantation. There were 2 perioperative deaths (4%). Prior to the procedure, all reported either NYHA Class III or IV symptoms compared to none at 1-year follow-up. Improvement in cardiodynamic assessments was consistent with the clinical improvements.
Recent studies of TASH confirm earlier reported results. (9, 10) One nonrandomized cohort study compared the outcomes of 51 patients who were treated with TASH (n=25) or myectomy (n=26). (9) Both treatment groups had reduced left ventricular outflow obstruction and significantly improved NYHA functional class immediately after treatment and at 3-month follow-up. However, reductions in pressure gradients were significantly lower in the myectomy group immediately after the procedure and during the 3-month follow-up than in the TASH group. Both groups had conduction system blocks (11 in TASH [9 with complete right bundle branch block and 2 with complete left bundle branch block] and 16 in myectomy [all had complete left bundle branch block]). Of those with conduction system blocks, 6 TASH patients required permanent pacemakers versus 2 patients in the myectomy group. Gietzen et al. reported that 129 patients receiving TASH had significant beneficial clinical and hemodynamic effects after a median follow-up of 7 months regardless of whether the patients’ pre-TASH obstruction was resting or provocable. (10)
In 2011, Jensen et al. (11) reported the long-term outcome of 313 percutaneous transluminal septal myocardial ablation (PTSMA) procedures performed in 279 patients with hypertrophic obstructive cardiomyopathy aged 59±14 years from 1999 to 2010 in 4 Scandinavian centers. Sixty-nine percent of patients had ≥1 comorbidity at baseline. The median (interquartile range) of left ventricular outflow tract gradient at rest was reduced from 58 mm Hg (34 to 89 mm Hg) at baseline to 12 mm Hg (8 to 24 mm Hg) at 1-year (P<0.001) and during Valsalva maneuver from 93 mm Hg (70 to 140 mm Hg) to 21 mm Hg (11 to 42 mm Hg) (P<0.001). The proportion of patients with syncope was reduced from 18% to 2% (P<0.001), and the proportion in NYHA class III/IV was reduced from 94% to 21% (P<0.001). All treatment effects remained stable during the follow-up. NYHA class III/IV at the most recent follow-up (2.9±2.6 years) was associated with diabetes mellitus (P=0.03), chronic obstructive pulmonary disease (P=0.02), and valve disease unrelated to hypertrophic cardiomyopathy (P<0.01). In-hospital mortality was 0.3%. The 1-, 5- and 10-year survival rates were 97%, 87%, and 67%, respectively (P=0.06 versus an age- and sex-matched background population) in all patients and 99%, 94%, and 88%, respectively (P=0.12) in patients aged <60 years (48±9 years, n=141). Age (hazard ratio, 1.07; 95% CI, 1.03 to 1.1) was the only predictor of survival. The authors concluded that the in-hospital mortality after PTSMA was low despite considerable comorbidities. The hemodynamic and symptomatic effects were sustained long term. The long-term symptomatic outcome was associated with baseline comorbidities. The 10-year survival rate was comparable to that in an age- and sex-matched background population, and age was the only predictor of survival. (10)
Also in 2011, Jensen et al. (12) reported on long-term survival and the risk of sudden cardiac death (SCD) after PTSMA in patients with hypertrophic obstructive cardiomyopathy (HOCM). Survival and SCD in 77 PTSMA-treated patients (follow-up 3.5 ± 2.8 years) were analyzed. The future risk of SCD was assessed by risk stratification for SCD in 57 PTSMA patients at long-term follow-up (3.8 ± 2.8 years). The five years’ survival of the PTSMA cohort (age 61 ± 12 years) was 83% compared to 79% in a control cohort (n = 90) of patients (age 52 ± 17 years) with hypertrophic cardiomyopathy (HCM) (Log Rank p = 0.8), and 91% (p = 0.01) in the background population. Five-year survival free of SCD was 94% after PTSMA compared to 99% (p = 0.13) in the HCM control cohort. Eight percent of patients had two or more risk factors for SCD at follow-up. The authors concluded that the survival in the PTSMA-treated patients and in the HCM control cohorts was similar. The incidence of SCD and the future risk of SCD assessed by risk factors were not increased in the PTSMA cohort compared to the HCM control cohort. The excess mortality in the PTSMA cohort compared to the background population seems to be related to HCM rather than PTSMA.
In 2016, Veselka et al. (14) reported long-term outcomes of a large multinational ASA registry (Euro-ASA registry). The analysis included a total of 1275 highly symptomatic patients with HCM treated with alcohol septal ablation (ASA) from January 1996 through February 2015. The HCM diagnosis was made by cardiologists experienced in managing the disease. ASA was performed by experienced interventional cardiologists and all procedures were guided by myocardial contrast echocardiography. The volume of alcohol injected during ASA ranged from 0.4 to 11 ml, however, 90% of individuals were treated with a dose of 1-3 ml. There were differences in post-procedural follow-up among participating centers but typically follow-up occurred at 3-6 months’ post ASA and then annually. Thirteen (1%) deaths occurred within 1 month of ASA: four died of heart failure, three of pulmonary embolism, two of cardiac tamponade, one of stroke, one of carcinoma and one SCD. A total of 171 (13%) deaths occurred overall during follow-up. Median follow-up time of survival analysis was 5.7 years with 5 individuals (0.4%) lost to follow-up. Rates of survival at 1, 5 and 10 years’ post ASA were 98%, 89% and 77%, respectively. Independent predictors of all-cause mortality were higher age at ASA, septum thickness prior to ASA, NYHA class before ASA and left ventricular (LV) outflow tract gradient at the last clinical check-up. Long-term survival was comparable with similar reports of treatment by myectomy. The conclusion states that "patients with obstructive HCM treated at tertiary centres have both low peri-procedural and long-term mortality after ASA."
Summary of Evidence
In summary, the data suggest that TASH, similar to myotomy/myomectomy, is associated with marked symptomatic and cardiodynamic improvement. It is not clear, however, whether the minimally invasive nature of TASH is associated with a decreased perioperative mortality rate. In the larger studies reviewed here, in patients undergoing myotomy/myomectomy alone, the perioperative mortality rate appears to range between 0% and 3%, which appears to be similar to the perioperative mortality rate reported for TASH. TASH appears to be associated with a high risk of atrioventricular heart block necessitating permanent pacemaker implantation. The long-term outcomes of myotomy/myomectomy appear to be satisfactory. Shorter hospital stays may make TASH more desirable in older patients with comorbid conditions, however, there is concern regarding the arrhythmogenicity of the infarcted septum, particularly since patients with hypertrophic cardiomyopathy are at high risk for complex ventricular arrhythmias. In addition, TASH will only cause reduction of the septum and will not be sufficient to relieve the outflow tract obstruction if there is elongation of the anterior or posterior leaflet of the mitral valve.
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1. Maron, MS. Hypertrophic cardiomyopathy: Nonpharmacologic treatment of left ventricular outflow tract obstruction. In: UpToDate, Post TW (Ed), UpToDate, Waltham, MA. Available at <http://www.uptodate.com> (accessed 2017 May 31).
2. Mohr R, Schaff HV, Danielson GK, et al. The outcome of surgical treatment of hypertrophic obstructive cardiomyopathy. Experience over 15 years. J Thorac Cardiovasc Surg. 1989; 97(5):666-74. PMID 2709859
3. Robbins RC, Stinson EB. Long-term results of left ventricular myotomy and myectomy for obstructive hypertrophic cardiomyopathy. J Thorac Cardiovasc Surg. 1996; 11(3):586-94. PMID 8601973
4. Schönbeck HM, Brunner-La Rocca HP, Vogt PR, et al. Long-term follow-up in hypertrophic obstructive cardiomyopathy after septal myectomy. Ann Thorac Surg. 1998; 65(5):1207-14. PMID 9594839
5. Seggewiss H, Faber L, Gleichmann U. Percutaneous transluminal septal ablation in hypertrophic obstructive cardiomyopathy. Thorac Cardiovasc Surg. 1999; 47(2):94-100. PMID 10363608
6. Kuhn H, Gietzen FH, Leuner C, et al. Transcoronary ablation of septal hypertrophy (TASH): a new treatment option for hypertrophic obstructive cardiomyopathy. Z Kardiol. 2000; 89(suppl 4):IV41-54. PMID 10810776
7. Gietzen FH, Leuner CJ, Raute-Kreinsen U, et al. Acute and long-term results after transcoronary ablation of septal hypertrophy (TASH). Catheter interventional treatment for hypertrophic obstructive cardiomyopathy. Eur Heart J. 1999; 20(18):1342-54. PMID 10462469
8. Lakkis NM, Nagueh SF, Dunn JK, et al. Nonsurgical septal reduction therapy for hypertrophic obstructive cardiomyopathy: one-year follow-up. J Am Coll Cardiol. 2000; 36(3):852-5. PMID 10987610
9. Qin JX, Shiota T, Lever HM, et al. Outcome of patients with hypertrophic obstructive cardiomyopathy after percutaneous transluminal septal myocardial ablation and septal myectomy surgery. J Am Coll Cardiol. Dec 2001; 38(7):1994-2000. PMID 11738306
10. Gietzen FH, Leuner CJ, Obergassel L, et al. Role of transcoronary ablation of septal hypertrophy in patients with hypertrophic cardiomyopathy, New York Heart Association functional class III or IV, and outflow obstruction only under provocable conditions. Circulation 2002; 106(4):454-9. PMID 12135945
11. Jensen MK, Almaas VM, Jacobsson L, et al. Long-term outcome of percutaneous transluminal septal myocardial ablation in hypertrophic obstructive cardiomyopathy: a Scandinavian multicenter study. Circ Cardiovasc Interv. Jun 2011; 4(3):256-65. PMID 21540441
12. Jensen MK, Havndrup O, Hassager C, et al. Survival and sudden cardiac death after septal ablation for hypertrophic obstructive cardiomyopathy. Scand Cardiovasc J. Jun 2011; 45(3):153-60. PMID 21604920
13. Jensen MK, Prinz C, Horstkotte D, et al. Alcohol septal ablation in patients with hypertrophic obstructive cardiomyopathy: low incidence of sudden cardiac death and reduced risk profile. Heart. Jul 2013; 99(14):1012-7. PMID 23644300
14. Veselka J, Jensen MK, Liebregts M, et al. Long-term clinical outcome after alcohol septal ablation for obstructive hypertrophic cardiomyopathy: results from the Euro-ASA registry. Eur Heart J. May 2016. 14;37(19):1517-1523. PMID 26746632
15. Transcoronary Ablation of Septal Hypertrophy (TASH) (Archived). Chicago, Illinois: Blue Cross Blue Shield Association Medical Policy Reference Manual (2010 November) Medicine 2.02.14.
|6/15/2018||Reviewed. No changes.|
|7/15/2017||Document updated with literature review. Coverage unchanged.|
|5/15/2016||Reviewed. No changes.|
|9/1/2015||Document updated with literature review. Coverage unchanged.|
|11/15/2014||Reviewed. No changes.|
|10/15/2013||Document updated with literature review. Coverage unchanged.|
|1/1/2010||Revised/Updated Entire Document, coverage remains medically necessary as a treatment of hypertrophic obstructive cardiomyopathy|
|7/1/2007||Revised/Updated Entire Document|
|8/15/2003||Revised/Updated Entire Document|
|5/1/1999||New Medical Document|
|Title:||Effective Date:||End Date:|
|Transcoronary Ablation of Septal Hypertrophy (TASH)||07-15-2017||06-14-2018|
|Transcoronary Ablation of Septal Hypertrophy (TASH)||05-15-2016||07-14-2017|
|Transcoronary Ablation of Septal Hypertrophy (TASH)||09-01-2015||05-14-2016|
|Transcoronary Ablation of Septal Hypertrophy (TASH)||11-15-2014||08-31-2015|
|Transcoronary Ablation of Septal Hypertrophy (TASH)||10-15-2013||11-14-2014|
|Transcoronary Ablation of Septal Hypertrophy (TASH)||01-01-2010||10-14-2013|
|Transcoronary Ablation of Septal Hypertrophy||07-01-2007||12-31-2009|
|Transcoronary Ablation of Septal Hypertrophy (TASH)||08-15-2003||06-30-2007|