MINISTRY OF EDUCATION AND TRAININGS MINISTRY OF HEALTH
HANOI MEDICAL UNIVERSITY
ĐINH HUỲNH LINH
TRANSCATHETER AORTIC VALVE
IMPLANTATION FOR MANAGEMENT OF
PATIENTS WITH SEVERE AORTIC STENOSIS
DOCTORAL THESIS SUMMARY
HANOI – 2020
BỘ GIÁO DỤC VÀ ĐÀO TẠO BỘ Y TẾ
TRƯỜNG ĐẠI HỌC Y HÀ NỘI
TRANSCATHETER AORTIC VALVE
IMPLANTATION FOR MANAGEMENT OF
PATIENTS WITH SEVERE AORTIC STENOSIS
Speciality: Cardiology
Code: 62720141
DOCTORAL THESIS SUMMARY
HÀ NỘI - 2020
1
INTRODUCTION
Surgical aortic valve replacement is the treatment for severe
symptomatic aortic stenosis. However, in clinical practice, many
patients do not undergo surgery, owing to the presence of multiple
coexisting conditions such as coronary heart disease, left ventricular
dysfunction, renal failure, chronic pulmonary disease, diabetes.
Transcatheter aortic valve implantation (TAVI) is a less invasive
approach, with comparable long-term outcomes, and less complications
than surgery. Since the first TAVI case in 2002, nearly 500 thousands
TAVI cases have been performed all over the world. Indications for
TAVI have been expanded, from very high surgical risk patients, to
high, then moderate and low surgical risk.
In Vietnam, the first TAVI case was performed in 2011. There
has been rapid growth in its use. This study was conducted, titled
“Transcathter Aortic Valve Implantation for management of
patients with severe aortic stenosis”, with two objectives:
1. Describe clinical and sub-clinical features of severe aortic
stenosis patients underwent TAVI in Vietnam, from 2013 to 2019
2. Evaluate safety and efficacy of TAVI in these patients
CONTRIBUTIONS OF THE STUDY
In Vietnam, it is the first time the safety and efficacy of TAVI
were evaluated, especially among high surgical risk patients. The
outcomes, as well as complications of TAVI in our study, are similar to
other TAVI studies in the world, showing this procedure can be
performed effectively and safely in heart centres in Vietnam.
The study has evaluated the role of echocardiography, multi-slice
CT of aortic valve, invasive catheterization, in the diagnosis of aortic
stenosis, and in screening suitable candidates for TAVI. These results
can provide the foundation for standardizing TAVI protocol in heart
centres in Vietnam.
STRUCTURE OF THE THESIS
The thesis contains 119 pages, including: Introduction (2 pages),
Background (30 pages), Methods (19 pages), Results (28 pages),
Discussion (36 pages), Conclusions (2 pages), and Recommendations
(1 page). There are 20 figures, 32 tables, 38 graphs, and 147 references.
2
CHAPTER 1
BACKGROUND
1.1. Etiology and pathophysiology of aortic stenosis
There are 3 main etiologies of aortic stenosis (AS): congenital
aortic valve disease (unicuspid or bicuspid), rheumatic heart disease,
and degeneration of aortic valve. Among elderly, the most common
cause is severe calcification and degeneration of aortic valve leaflets,
resulting in reduction of aortic valve area.
AS will induce trans-aortic valve gradient, causing several
pathophysiological consequences, including (1) left ventricular
hypertrophy and systolic dysfunction, (2) diastolic dysfunction, (3)
myocardial ischemia due to reduced coronary perfusion, (4) low
periperal perfusion, (5) post-stenotic aortic dilation.
1.2. Clincal and sub-clinical manifestations of AS patients
Clinical symptoms include fatigue, decrease exercise tolearnce,
dypsnea on exertion, angina, syncope, and end-stage heart failure
symptoms.
Echocardiogram is the basic investigation for the diagnosis,
evaluation, and prognosis of AS. Echocardiographic assessment with
provide indications of aortic valve replacement (AVR). Low-dose
dobutamine stress echocardiogram is performed to differentiate true
severe AS from pseudosevere AS in low flow-low gradient patients.
1.3. Management of AS
1.3.1. Medical management
Medical management of heart failure may reduce symptoms, but
do not prolong life in symptomatic patients.
1.3.2. Balloon aortic valvuloplasty
Percutaneous balloon aortic valvuloplasty relieves stenosis by
fracturing calcific deposits within the valve leaflets, resulting in valve
opening and lower trans-aortic gradient. However, the restenosis rate is
high. Therefore, balloon aortic valvuloplast has limited role clinical
settings of congenital severe AS, and as a bridge to AVR..
1.3.3. Surgical aortic valve replacement (SAVR)
SAVR has been the mainstay of treatment for symptomatic AS
patients, as it offers substantial improvements in symptoms and life
expectancy. However, there are several SAVR-related complications,
3
such as severe bleeding, infection, biosthetic valve dysfunction. In
clinical practice, at least 33% of patients cannot undergo surgery. For
these patients, a less invasive treatment may be a worthwhile
alternative.
1.4. Transcatheter aortic valve implantation (TAVI)
Since the first-in-human transcatheter aortic valve implantation
(TAVI) performed by Alain Cribier in 2002, this innovative procedure
has gained widespread recognition as the treatment of choice for severe
aortic stenosis. Over the same period, TAVI has evolved from a
challenging intervention to a standardised, simple, and streamlined
procedure.
The standardized TAVI protocol includes the following steps: (1)
Heart team discussion to stratify surgical risk, (2) echocardiogram, (3)
ECG-gated MSCT of the aortic valve to choose the suitable size of the
device, (4) TAVI procedure in the cathlab or hybrid operation room
(OR).
Potential complications of TAVI include: death, stroke,
myocardial infarction, bleeding, device embolization, acute kidney
injury, permanent pacemaker implantation, paravalvular leak,…
Compared with SAVR, the higher incidence of pacemaker
implantations is the only remaining concern of TAVI.
Clinical trials have shown the efficacy of TAVI in many clinical
settings:
- In PARTNER 1B, TAVI is superior to medical treatment in
inoperable patients
- In PARTNER 1A, TAVI is similar to SAVR in high surgical risk
populations
- In PARTNER 2 and SURTAVI trials, TAVI has comparable
outcomes with SAVR in intermediate-risk patients.
- In PARTNER 3, NOTIOn, and EVOLUT trials, TAVI is similar of
better than SAVR in low-risk patients
With recent results from these studies, the indications for TAVI
have changed dramatically, shifting quickly from compassionate cases,
to inoperable and high-risk patients, and more recently towards
intermediate-risk and low-risk populations.
