TAVR

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Durability of Transcatheter Aortic Bioprosthesis

Abhishek Sharma, MD

“On résiste à l’invasion des armées; on ne résiste pas à l’invasion des idées” (No one can resist an idea whose time has come) – Victor Marie Hugo

Transcatheter aortic valve replacement (TAVR) has been established as an appropriate treatment option for patients with symptomatic severe aortic stenosis who are at intermediate, high, or prohibitive surgical risk. While we all are eagerly waiting for the results of large scale randomized trial evaluating “The Safety and Effectiveness of the SAPIEN 3 Transcatheter Heart Valve in Low Risk Patients With Aortic Stenosis” (PARTNER-3), Nordic Aortic Valve Intervention Trial (NOTION) results did provide an insight into potential role of TAVR in low risk populations. This small randomized trial compared TAVR (using self-expanding bioprosthesis–Corevalve) with surgical aortic valve replacement (SAVR) in an all-comers patient cohort in 3 Nordic centers1. Among 280 patients, 81.8% of patients in this study were low risk, as assessed by Society of Thoracic Surgeons score (<4%). In the low risk cohort, at 6 years, the rates of all-cause mortality were similar for TAVR (42.5%) and SAVR (37.7%) patients (p = 0.58)1.

These results are very encouraging and might play an important role in providing non-surgical option to low risk patient populations. However, this also raises an important question regarding the long-term durability of transcatheter bioprosthetic valve in relatively healthy and low-intermediate risk patients with longer life expectancies, especially when compared with SAVR. Interestingly, in studies reporting long-term outcomes and performance of SAVR, the definition of durability of surgical bioprosthetic valves has wide variation spanning from the need for re-operation to integration of clinical and echocardiographic outcomes. Such variations make it difficult to compare durability of SAVR and TAVR. To overcome this, standardized definitions of structural valve deterioration (SVD) and nonstructural valve deterioration (NSVD) have been proposed2. In this European task force committee guidelines consensus statement, severe SVD have been defined as either mean gradient ≥40 mm Hg and/or ≥20 mm Hg increase from baseline; AND/OR  peak velocity ≥4 m/s and/or ≥2 m/s increase from baseline; AND/OR severe new or worsening intraprosthetic aortic regurgitation (AR).

Using above criteria, Blackman and colleagues have reported incidence of SVD 5 to 10 years post-procedure using U.K. TAVI (United Kingdom Transcatheter Aortic Valve Implantation) registry data3.  Among 241 patients who underwent TAVR from 2007 to 2011, severe SVD was observed in <1% patients. 91% of patients remained free of SVD on median follow up period of 5.8 years (range 5 to 10 years)3.

Thus, transcatheter bioprosthetic aortic valves are durable. But how do they fare when compared to surgical bioprosthesis?  Søndergaard and colleagues provided answer to this question using 6-year follow up data from NOTION trial1. The effective orifice area was larger and mean gradient was lower after TAVR when compared to SAVR. Further, this significant difference was sustained on 6 years follow-up. Using standardized definitions, authors have reported higher rate of SVD for SAVR than TAVR (24.0% vs. 4.8%; p < 0.001), whereas there were no differences in NSVD (57.8% vs. 54.0%; p = 0.52); endocarditis (5.9% vs. 5.8%; p = 0.95) or bioprosthetic valve failure rates through 6 years (6.7% vs. 7.5%; p = 0.89)1.

These results are convincing, but caution should be exercised while extrapolating them to clinical practice. In report from U.K TAVI registry, data was analyzed for only 241 patients (from >1500 patients) due to lack of echocardiographic data both at baseline and >5 years. Further, <15% patients had follow-up beyond 8 years. Later is relevant as SVD of porcine and pericardial aortic bioprostheses have been reportedly begins 8 years after implantation4. Similarly in report from NOTION trial, 6-year follow-up data was available only in 50 TAVR and 50 SAVR patients. Also, a core lab did not adjudicate these echocardiographic measurements.

Despite limitations, data from the UK TAVI registry and NOTION trial are very encouraging and supportive to extend indications of TAVR to a relatively younger and healthier patient population. This is especially important as global numbers of TAVR cases are projected to be double by 2025.

 

References:

  1. Søndergaard L, Ihlemann N, Capodanno D, et al. Durability of transcatheter and surgical bioprosthetic aortic valves in patients at lower surgical risk. J Am Coll Cardiol, 73 (2019), pp. 546-553
  2. Capodanno DM, Petronio AS, Prendergast B, et al. Standardised definitions of structural deterioration and valve failure in assessing long-term durability of transcatheter and surgical bioprosthetic valves. A consensus statement from the European Association of Percutaneous Cardiovascular Interventions (EAPCI) in collaboration with the European Society of Cardiology (ESC). Eur Heart J, 38 (2017), pp. 3382-3390
  3. Blackman DJ, Saraf S, MacCarthy PA, et al. Long-term durability of transcatheter aortic valve prostheses. J Am Coll Cardiol, 73 (2019), pp. 537-545
  4. Foroutan F, Guyatt GH, O’Brien K, et al. Prognosis after surgical replacement with a bioprosthetic aortic valve in patients with severe symptomatic aortic stenosis: systematic review of observational studies. BMJ, 354 (2016), p. i5065

 
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Women & TAVR: “I Don’t Want Any Procedure”

Mirvat Alasnag, MD

Round 1…

Patient’s son-in-law: “My mother has been turned down for surgery. They tell me her mortality rate at 2 years is high since she had fluids collecting in her lungs. They told me to ask you about catheterization.”

Me: “Yes, she does have a tight aortic valve and did develop heart failure. She is also very high risk for surgery. Percutaneous or catheter-based replacement may be an option. She will need a CT Scan first to determine if she is suitable for that treatment.”

The patient’s son-in-law asked me only one question, but a number of questions rushed through my head.

When is a good time to give the patient a contrast load after her recent admission with pulmonary edema? How safe is contrast given her borderline renal dysfunction and recent pulmonary edema? What is the outcome of trans-catheter aortic valve replacement (TAVR) in women?

I realized that there were no concrete answers. Irrespective of risk of contrast induced nephropathy, she needs the CT Angiogram. Irrespective of the timing, she remains high risk for recurrent pulmonary edema with or without the 50-60 cc of contrast given during the CT scan. Irrespective of her gender, TAVR maybe her only option. So, the CT scan was done with a small amount of contrast & her renal function remained unchanged and she did not develop pulmonary edema. She had borderline parameters with a short distance from the aortic valve annulus to left main, significant calcification into her LVOT, small tortuous and calcified common iliac arteries bilaterally. She was not an “ideal” candidate.

 

Round 2…

 

Me: “You are at a higher risk of coronary occlusion. We can place an undeployed stent preemptively in the coronary artery. Your risk of requiring a pacemaker is high and we’ve notified our electrophysiologist. Your risk of rupture is high, so we plan to use a self-expanding valve. We may need to use an alternative access like your armpit artery.”

Patient: “I don’t want any procedure.”

Patient’s son-in-law: “Is there anything else that we can do that is less risky?”

Me: “Palliative balloon valvuloplasty, but the gradient will increase again in 6-12 months.”

Patient: “I don’t want any procedure.”

Patient’s son (in-law): “Can we repeat this valvuloplasty every 6 months if need be?”

Patient: “I don’t want procedure.”

*Awkward silence.*

Me: “She does not want any procedure. It is time you and I listen to her.”

 

This patient was referred to me by a colleague from another hospital. She had no sons of her own but had her son-in-law to accompany her. She was a small, frail, soft spoken, elderly lady. She was also grateful for the care she received. We immediately had the surgeons evaluate her. While the surgeons were examining her, I did a quick literature review:

Data from Vancouver demonstrated that the mortality rate at 30 days after TAVR was 6.5% in women and 11.2% in men after accounting for other variables.1 This advantage for the female gender was maintained at 1 year as confirmed by the PARTNER Trial sub-analysis. Whether this was due to worse surgical outcomes in women or an advantage of TAVR in women was further explored by Humphries et al. Although vascular complications were higher in women, the overall survival rate at 2 years was 72.1% for women and 61.7% for men. Real world international registry and the first WIN TAVR registry further confirmed that high risk women had low 30-day and one-year mortality and stroke rates.2-4

Naturally, I picked up the conversation where the surgeons left off. In retrospect, even as a woman interventional cardiologist, was I dismissive of my patient’s own preference? Do we have a tendency to ignore female patients’ wishes more than men? Do we have a tendency to ignore elderly patients’ wishes more than younger ones? Or do we find it difficult to resolve to hospice care even before exhausting all options? It may be a combination of all of these. I don’t normally dismiss my patients’ wishes, but this time, I was clearly not listening. Maybe I listened to my colleague (a physician) and maybe I just grew attached to this soft spoken grateful woman…and I couldn’t resign myself to writing hospice care for her. Women..men..no matter, we make imperfect choices at times driven by our humanity. May that imperfection continue to drive us to care.

 

References:

1. Humphries KH, Toggweiler S, Rodés-Cabau J, et al. Sex differences in mortality after transcatheter aortic valve replacement for severe aortic stenosis. J Am Coll Cardiol 2012;60:882–6.

2. Williams M, et al. Sex-related differences in outcomes after transcatheter or surgical aortic valve replacement in patients with severe aortic stenosis: Insights from the PARTNER Trial (Placement of Aortic Transcatheter Valve). J Am Coll Cardiol. 2014 Apr 22;63(15):1522-8.

3. Chieffo A, et al. 1-Year Clinical Outcomes in Women After Transcatheter Aortic Valve Replacement: Results From the First WIN-TAVI Registry. JACC Cardiovasc Interv. 2018 Jan 8;11(1):1-12.

4. Chieffo A, et al. Acute and 30-Day Outcomes in Women After TAVR: Results From the WIN-TAVI (Women’s INternational Transcatheter Aortic Valve Implantation) Real-World Registry. JACC Cardiovasc Interv. 2016 Aug 8;9(15): 1589-600.

 

 
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The Significant Areas of Interest in the Field of Cardiac Imaging in 2018

Renee Bullock-Palmer, MD

There were several exciting developments in 2018 with regards to cardiac imaging. The role of the cardiac imager is becoming increasingly relevant in today’s cardiology practice environment and bridges across several subspecialties in Cardiology, such as electrophysiology with the use of transesophageal echocardiography (TEE) in the placement of left atrial appendage closure devices. These devices include Watchman and interventional cardiology with structural and valvular heart disease and echocardiographic guidance with transaortic valve replacement (TAVR), percutaneous mitral valve repair with MitralClip, as well as atrial septal and ventricular septal closure devices. The field of cardiac imaging has matured over the years and not only includes echocardiography and nuclear cardiology, but also includes advanced imaging with cardiac magnetic resonance imaging (cMRI) and cardiac computed tomography. In addition, there has been the rise of the interventional echocardiographer specializing in the use of echocardiography in guiding percutaneous and surgical treatment of structural heart disease. In fact, there has been recognition of cardiac imaging by several professional societies such as the American College of Cardiology with publication of the state-of-the-art paper, The Future of Cardiac Imaging Report of a Think Tank Convened by the American College of Cardiology1. There have also been several disease states that have been positively influenced by the development of new diagnostic technology in cardiac imaging, such as cardiac amyloidosis. Cardiac imaging has also positively influenced preventive cardiology with release of the latest American Heart Association (AHA)/ American College of Cardiology (ACC) 2018 Cholesterol Management Guidelines2. The following areas were, in my opinion, considered topics of great interest in 2018 in the field of cardiac imaging.

 

Nuclear Imaging

Cardiac Amyloidosis. For several years, cardiac amyloidosis, particularly transthyretin type (ATTR type), was thought to be a diagnosis that was very difficult to make with endomyocardial biopsy being the only method to confirm the diagnosis. However, nuclear cardiac imaging has changed the landscape of this disease with the novel application of old technology with the use of technetium 99m pyrophosphate (Tc-99m PYP) in the diagnosis of ATTR type cardiac amyloidosis3. The sensitivity and specificity of this technique in diagnosing this disease state is >95%, and oftentimes avoids the need for endomyocardial biopsy to make this diagnosis4. The development of this technique in diagnosing the disease has increased the recognition of this disease in many patients with diastolic heart failure, and even in patients with severe aortic valve stenosis undergoing TAVR. This has also led to greater research and development of new treatments for this disease, such as tafamidis, patisiran and inotersen. The development of these medications will hopefully improve the overall prognosis for patients with this disease.

 

Echocardiography

The Rise of the Interventional Echocardiographer in Structural Cardiac Imaging. There has been increasingly relevant areas of interest in structural heart disease, such as percutaneous mitral valve repair with MitralClip, especially with the release of the study findings from the COAPT trial5.  In addition, transaortic valve replacement (TAVR) has become increasingly available for many patients with severe aortic valve stenosis, and many institutions have began offering this therapy to many of their patients. Additionally, left atrial appendage occlusive devices such as the Watchman device are being increasingly used in patients with atrial fibrillation who are at high risk for hemorrhagic complications with anticoagulation, despite having indications for thromboembolic prophylaxis. With these new developments, there has been the rise of the interventional echocardiographer, who serves a vital role with the use of echocardiography in guiding the placement of these devices in the treatment of structural heart disease. Many fellows are now seeking additional training in this field to meet this demand, as this area has invited a growing interest in the cardiology field and has attracted many trainees.

 

Cardiac Computed Tomography

The revisiting of Coronary Calcium Score as a Powerful Tool in Preventive Cardiology. The release of the latest AHA/ACC Cholesterol Management Guidelines has been an area of great interest in the field. The latest guidelines have included the use of coronary calcium scoring with cardiac CT as a tool to further risk stratify patients to guide the use of pharmacologic therapy for patients with hyperlipidemia2. This has led to  the resurgence of Cardiac CT for coronary calcium scoring as a valuable tool for cardiologists in the field of preventive cardiology.

Utility of Cardiac CT in the assessment of Women with suspected Cardiovascular Disease.  There has also been the increasing recognition of Cardiac CT as a useful diagnostic tool for women suspected of having cardiovascular disease (CVD)6. Hopefully, this will result in the increased appropriate use of Cardiac CT in the management of CVD in women.

 

Cardiac MRI

The complementary role of Cardiac MRI with echocardiography and assessment of valvular and structural heart disease. Cardiac MRI has become an established imaging modality in the assessment of valvular heart disease. This has been embraced by the American Society of Echocardiography’s latest Valvular Guidelines, which includes cardiac MRI as playing a complementary role in the assessment of the severity and etiology of valvular heart disease7. The use of Cardiac MRI is also useful in the assessment of other disease states, such hypertrophic cardiomyopathy and risk assessment for sudden death8.

The rise of Cardiac MRI compatible devices. There has also been the development of Cardiac MRI compatible devices which now allows many patients with these devices to be able to have cardiac MRIs performed safely. Cardiac MRI is therefore a viable diagnostic tool for these patients.

The first administration of certification board exam in cardiovascular magnetic resonance imaging (CBCMR).  With the maturation of Cardiac MRI as a viable imaging modality, 2019 will see the inaugural administration of the first certification exam in cardiovascular magnetic resonance imaging (CBCMR), which will occur between May 7 – June 7, 2019, and the 2019 application window will open on January 15, 2019. ​​

 

Conclusion:

With the dawn of a new year in 2019, it is clear that the future of cardiac imaging is very bright. I am looking forward to many more promising developments in this field and hope that this field will continue to attract many more talented cardiologists in this area of cardiology.

 

References:

  1. Douglas PS, Cerqueira MD, Berman DS, Chinnaiyan K, Cohen MS, Lundbye JB, et al. The Future of Cardiac Imaging Report of a Think Tank Convened by the American College of Cardiology. J Am Coll Cardiol Img 2016;9:1211–23.
  2. Grundy SM, Stone NJ, Bailey AL, Beam LT, Birtcher KK, et al. 2018AHA/ACC/AACVPR/AAPA/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA Guideline on the Management of Blood Cholesterol. JACC Nov 2018, 25709; DOI: 10.1016/j.jacc.2018.11.003.
  3. Dorbala S, Bokhari S, Miller E, Bullock-Palmer RP, Soman P, Thompson R. ASNC Practice Points: 99mTechnetium-Pyrophosphate Imaging for Transthyretin Cardiac Amyloidosis (American Society of Nuclear Cardiology website). 2018. Available at: https://www.asnc.org/Files/Practice%20Resources/Practice%20Points/ASNC%20Practice%20Point-99mTechnetiumPyrophosphateImaging2016.pdf.
  4. Gillmore JD, Maurer MS, Falk RH, Merlini G, Damy T, Dispenzieri A, et al. Nonbiopsy Diagnosis of Cardiac Transthyretin Amyloidosis. Circulation. 2016 Jun 14;133(24):2404-12. Doi: 10.1161/CIRCULATIONAHA.116.021612. Epub 2016 Apr 22.
  5. Stone GW, Lindenfeld J, Abraham WT, Kar S, Lim DS, Mishell JM,et al. COAPT Investigators.Transcatheter Mitral-Valve Repair in Patients with Heart Failure. N Engl J Med. 2018 Dec 13;379(24):2307-2318. doi: 10.1056/NEJMoa1806640. Epub 2018 Sep 23.
  6. Truong QA, Rinehart S, Abbara S, Achenbach S, Berman DS, Bullock-Palmer R,et al. SCCT Women’s Committee.Coronary computed tomographic imaging in women: An expert consensus statement from the Society of Cardiovascular Computed Tomography. J Cardiovasc Comput Tomogr. 2018 Nov – Dec;12(6):451-466. doi: 10.1016/j.jcct.2018.10.019. Epub 2018 Oct 23.
  7. Zoghbi WA, Adams D, Bonow RO, Enriquez-Sarano M, Foster E, Grayburn PA, et al. Recommendations for Noninvasive Evaluation of Native Valvular Regurgitation A Report from the American Society of Echocardiography Developed in Collaboration with the Society for Cardiovascular Magnetic Resonance. J Am Soc Echocardiogr. 2017 Apr;30(4):303-371. doi: 10.1016/j.echo.2017.01.007. Epub 2017 Mar 14.
  8. Weng Z, Yao J, Chan RH, He J, Yang X, Zhou Y, He Y.Prognostic Value of LGE-CMR in HCM: A Meta-Analysis. JACC Cardiovasc Imaging. 2016 Dec;9(12):1392-1402. doi: 10.1016/j.jcmg.2016.02.031. Epub 2016 Jul 20. Review.

 

 
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AHA18: Notes From a Structural Heart Disease Specialist

Abhishek Sharma, MD

How can one experience science and scenic beauty together? You know the answer to this, if you attended this year’s annual Scientific Sessions of the American Heart Association (AHA) in the beautiful city of Chicago. AHA18 showcased the latest advancements and studies in the field of cardiovascular medicine and stroke.

 

AHA Coming Back To The Center Stage

I attended AHA Scientific Sessions for the first time when I was an intern. Science from different sub-specialties of cardiovascular and stroke was truly inspiring and triggered curiosity. However, over the years as I specialized in general cardiology, then interventional cardiology and structural heart disease (SHD), it became increasingly difficult to attend all major scientific meetings every year.  Meetings focused on sub-cardiovascular specialties had taken priority in my schedule in last few years. However, this has changed in 2018. As a SHD specialist I realized the need and importance of a multidisciplinary approach, and science that cuts across various specialties. With widespread adoption of heart team and brain team models, we have realized the importance and benefits of collaboration between physician and surgeons across different specialties.  AHA provides a perfect platform to present and promote such multidisciplinary science.

 

How Far We Came in the TAVR World

Two separate studies using national administrative databases reported significant reduction in the complications rates associated with transcatheter aortic valve replacement (TAVR).

In the first study, Dr. Sameer Arora and his colleagues at University of North Carolina School of Medicine, Chapel Hill, evaluated the complication rates following both TAVR and surgical aortic valve replacement (SAVR) using the Nationwide Inpatient Sample1.  They included more than 90,000 patients and reported reduction in all cause mortality (4% to 1%), vascular complications (8% to 5%), acute kidney injury (12% to 10%), need for blood transfusions (31% to 10%), and cardiogenic shock (3% to 1%) in patients who underwent TAVR between 2012 and 2015 [P < 0.001 for all].

However, there was an increase in the need for a permanent pacemaker implantation (2% to 12% %; P < 0.001). They also noted trends towards improvement in outcomes with SAVR during same period. Improvement in device profile and valve design, operator experience, and inclusion of patients with lower baseline risk could explain these outcomes with TAVR.

In the second study, Dr. Rajat Kalra, MBChB and colleagues at University of Minnesota, Minneapolis, analyzed rates of new-onset atrial fibrillation and its association with clinical outcomes among patients who underwent TAVR (N=48,715) and SAVR (N=122,765), also using the Nationwide Inpatient Sample from 2012 to 20152. The study reported rates of new-onset atrial fibrillation as 50.4% and 50.1% for TAVR and SAVR respectively. They also noted higher in-hospital mortality, and post procedure stroke, among patients who had new-onset AFib post TAVR or SAVR.

Results from both of these studies are in coherence with findings from clinical trials and our experience with TAVR. However, due to lack of randomization, long term follow up, potential confounders and potential of inappropriate coding, caution should be exercise in extrapolating results of these studies or comparing TAVR with SAVR based on such data.

 

Flyer from Future

In addition to various studies and presentations from all across the nation and the international scientific community, AHA18 had dedicated sessions for Structural Heart Disease, 3D imaging, and Artificial Intelligence, giving us a glimpse of the near future for SHD. Cardiac imaging is critical to plan and perform any transcatheter based structural heart disease procedure, and 3D printing has potential to revolutionize the treatment planning of patients with SHD as highlighted by Dr. Frank Rybicki (University of Ottawa) during his presentation at AHA18. A potential role of 3D bioprinting for preoperative planning for TAVR and SAVR and the future of this technology was further emphasized in another interesting talk “Personalized Care: Print your own valve,” by Dr. Kamal Khabbaz (Beth Israel Deaconess Medical Center, Harvard Medical School, MA).

My experience during 2018 session has reinforced my believe that AHA has the potential to be ‘The Platform’ to present and promote SHD science.

 

References:

  1. Arora S. Trends in inpatient complications after transcatheter and surgical aortic valve replacement in the TAVR era. Presented at: AHA 2018. November 11, 2018. Chicago, IL.
  2. Kalra R. New-onset atrial fibrillation after aortic valve replacement: evaluation of a national cohort. Presented at: AHA 2018. November 12, 2018. Chicago, IL.