This document discusses estimating the potential population eligible for cardiac resynchronization therapy (CRT) devices in England based on updated National Institute for Health and Clinical Excellence (NICE) guidelines. The authors analyzed epidemiological data and general practitioner records to estimate there are around 38,000-43,000 people eligible based on left ventricular dysfunction, heart failure symptoms, and electrocardiogram results. Even small increases in the proportion of eligible patients receiving CRT devices could significantly impact healthcare services due to the costs and specialist resources required.

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BACKGROUND
AIM
RESULTS
CONCLUSIONS
NICE TA 120
Heart failure is a common manifestation of heart disease, which impairs quality of life for many and
is often progressive, being a common cause or contributor to deaths in England. Cardiac
Resynchronisation Therapy (CRT) devices can improve quality and length of life for some people
with heart failure. Implantation in England has grown more than four-fold in ten years to exceed
8,000 of these costly devices in 2013/14.
The National Institute for Health and Clinical Excellence (NICE) recently changed its
recommendations for the use of these devices among people with mild heart failure, making access
more straightforward, with eligibility determined only on the basis of symptoms, ECG and
echocardiography. This raises questions about the future need and demand for these devices, that
are costly and require significant specialised training to implant.
NICE estimated potential CRT uptake of 120/million/year in 2007, but 8025 CRT devices
(150/million/year) were implanted in the England in 2013 (NICOR 2014). There are no reliable
estimates of the prevalence of patients with previous CRT device implantation.
Uptake of these devices in England has not been driven historically by NICE guidelines, but
establishing future uptake is important to plan finances, manpower and facilities.
To quantify the prevalent population with an indication for CRT under
NICE guidance (TA 314, 2014), which extends eligibility for these devices.
Methods.
Eligible populations were quantified by identifying relevant clinical
characteristics of left ventricular function (LVEF ≤35%), QRS duration
(≥120ms) on the ECG and heart failure symptoms (New York Heart
Association classification) in
I. published epidemiological studies and
II. monitoring of the Quality and Outcome Framework in the national GP
contract.
The published epidemiological evidence relevant to estimating the size of
the population eligible for device implantation was limited. Estimates had
therefore to be drawn from sources that were dated or of indirect
relevance.
The majority of those with undifferentiated symptomatic heart failure are
likely to have no ECG abnormalities (Shenkman et al. 2002), but perhaps
21% of those with mild symptoms (NYHA Grade II) will have an indication
for device implantation according to the criteria in NICE TA 314.
The majority of people with measurable left ventricular dysfunction have no
symptoms, but there are almost 800 per 100,000 people aged over 45 with
NYHA II heart failure (Davies et al. 2001). This suggests the prevalent
population eligible for CRT device implantation in England could be
38,000.
Application and limitations of epidemiological analysis in
planning access to specialised cardiology services
Dr Mark Lambert - Consultant in Public Health Specialised Commissioning (North East and Cumbria) and
Dr Chris Plummer - Consultant Cardiologist , Newcastle Hospitals NHS Foundation Trust
GPs in England identified 208,000 people in 2012 as having both
symptomatic heart failure and echocardiographic evidence of left
ventricular dysfunction. This slightly larger (and more pragmatically
defined) population base suggests there are perhaps 43,000 individuals
eligible for device implantation.
These estimates are both limited by the incomplete correlation between
documented clinical characteristics and criteria outlined by NICE.
The implication of these estimates was then explored in two scenarios-
based on potential increases in uptake, from 6.5% of eligible population
implanted currently to 10% (Scenario 1) and 13% (scenario 2).
Estimating the prevalence of patients with CRT indications is possible using existing
sources. The pool of eligible patients among people with mild (NYHA II) heart failure
is large compared to current implantation rates. Even small changes in referral
patterns could place considerable demands on services.
Experience from implementing NICE device guidance suggests that only a small
proportion of patients with CRT indications will receive this therapy.
NICE guidance that widens eligibility and reduces diagnostic requirements is likely
to increase demand for CRT implantation. The magnitude of that increase remains
uncertain.