In an age of fast cars and fast food, it is little surprise that speedy,
minimally invasive treatments have taken centre stage in important
treatment arenas. However, unlike cars and food, medical treatment,
when administered without delays and with minimal incisions to the human
body, can prove enormously effective at saving time and costs for the
patient and for the healthcare system, in general. That many of these
procedures are also clinically effective and sometimes, far superior to
regular treatments, is a factor that makes their availability as an
option indispensable in modern healthcare institutions.
Angioplasty,
as a treatment for a range of vascular indications, found its way into
the medical mainstream as a contending option to surgeries - procedures
that involve cutting open the body for suitable access to lesions, long
hospitalization periods, longer recovery times (equalized to longer
periods away from income-generating work) and huge medical bills.
In
1977, the angioplasty procedure, was developed by Dr.Andreas Gruentzig
and patients had the option of using a balloon in an effort to open a
blocked coronary artery. The procedure could be performed in a Cathlab
(an imaging area) in a span of a few hours and the patient could go
home, usually on the same day, greatly reducing the time and expense
burden on the patient, the hospital and the payers (where applicable).
The
balloon angioplasty or POBA (plain old balloon angioplasty, as
popularly called) offered short-term benefits. However longer-term
outcomes showed many arteries re-closing and requiring repeated
intervention; up to 30-40% of angioplasty patients were found to require
further angioplasty within six months. In an effort to reduce the
frequency of patients requiring re-intervention, scientists and
clinicians developed stents (metal wire-mesh scaffoldings) that could be
left behind to hold the artery open once the balloon was withdrawn. The
first stent was used in late 1980’s and by the end of the last century,
stents were being used in majority of PTCA (Percutaneous Transluminal
Coronary Angioplasty) procedures.
Bare metal stents, the earliest
scaffoldings, however carried the risk of restenosis, or the
re-narrowing of the arteries, resulting in occlusion of the stents.
To
address this issue, drug-eluting stents (DES) were developed as tools
for delivering medication directly to the arterial wall, to induce
delayed healing in order to reduce the incidence of restenosis. Drugs,
such as those from a family of immunosuppressants (the Limus group) and
mitotic inhibitors (Paclitaxel) are used for the purpose. Polymers (drug
carriers) are attached to the stents and these carry different chemical
components (drugs). The bioavailability of the drug in question is
vastly triggered by the carrier system, and depending on whether it is a
constant polymer, biodegradable polymer or even a non-polymer, elution
times for the drug range from a few days to a few months.
DES was
a major breakthrough in the space of interventional cardiology.
Drug-eluting stents have been extensively studied, and are generally
considered superior to bare-metal stents as they have shown a remarkable
reduction in restenosis and target vessel revascularization when
compared with bare metal stents.
The DES category of angioplasty
tools is currently experiencing extensions in clinical indications and
organ coverage, use of varied biocompatible metals (stainless steel,
cobalt chromium, platinum), advance in polymer/ drug carrier
technologies and the foray into multiple drug coatings. All these
efforts are geared towards ensuring greater user-friendliness, managing
thrombosis and avoiding restenosis.
A steady rate of development
in coronary stent technology, producing an equally steady stream of new
stent market introductions, is focused on shifting the concentration of
stent sales to the DES variety. DES is the world market leader in
turnover with an equal position compared to BMS. Around 1,50,000 stents
were used in India last year and DES contributed to around 50% of them.
However,
due to the requirement for longer dual anti-platelet therapy and late
in-stent thrombosis - two important factors forced to be considered post
implantation of a DES, clinicians and stent companies innovated on
treatments that can open up an occluded artery and deliver the drug
without use of a metal stent. This concept is now called the Drug
Eluting Balloon or DEB wherein a balloon is coated with a drug, avoiding
the use of a metal (that can cause restenoss) or a polymer (that can
cause thrombosis).
Use of DEB has extended the angioplasty
universe to non-compliant patients (hitherto unavailable for DES use),
critical bifurcation lesions and small vessels. Even restenosed arteries
can now be effectively treated with a DEB.
The DEB category, as
a treatment option, is being gradually but surely accepted around the
world. Its usage is growing in double digits in some key medical
markets. Because of its unique proposition, of associated cost and
patient compliance, clinicians are adding to the indications it can
treat, from regular angioplasties to a drug delivery tool in
valvuloplasties and more. DEB is also going beyond coronary
interventions and is now proven to be effective in treating medical
problems arising out of Peripheral Arterial Disease (PAD).
It
is a great boon for diabetic patients who are faced with eventual
amputation of their limbs. More studies and trials are being conducted
to make DEB more effective and more expansive in its reach and
application. Currently, almost 15% of all stenting opportunities can be
dealt with with just a DEB.
More pronounced today, is the trend
to experiment with combination devices, such as that of a DEB used with a
BMS, like in a bifurcation scenario. The field is open to further
investigational work and will pick up traction in the years to come.
Today,
Angioplasties or PCIs – Percutaneous Coronary Interventions, whether
with a BMS, DES or a DEB, lead the pack of treatment options for
cardiovascular diseases (CVD). The global coronary stents market was
valued at US$ 5.4 billion in 2009 and is forecasted to reach US $6.5
billion in 2016 after growing at a Compound Annual Growth Rate (CAGR) of
2.5% from 2009-2016. Globally, over 1.1 million such procedures are
performed annually and the number is expected to grow as a) more
indications are added to the treatment list every year, b) more
investments are made by governments and private players in capital
equipment necessary for the delivery of minimally invasive treatments
and c) changing demographics that ensure more people around the world
will age and more aggressive therapy like PCI will be needed to address
their CVD issues.
Some other factors that are contributing to the steady increase in PCIs in developed countries and in emerging markets are –
?
Increasing awareness about the latest medical technologies available
in the market and consequently rising demand for the same
? Shift from chronic to lifestyle diseases such as diabetes, obesity, high blood pressure and high cholesterol
? Rising per capita income has led to increased spending on healthcare by community
? Increasing healthcare expenditure outlay by governments
? Greater acceptance of minimally invasive surgery
India,
alone has an estimated 60 million patients each with heart disease,
diabetes and mental disability (all contributing towards CVD) and an
estimated 70 million cases will make India the world’s cardiovascular
disease capital by 2025.
Going forward there will be major forces
and developments impacting the angioplasty market, principally the
emergence of novel stent technologies like bio-absorbable drug coated
stents and newer generations of drug-eluting balloons.
The author is Director Clinical & Regulatory; Scientific PR Eurocor GmbH