Idiopathic Pulmonary
Fibrosis and Lung Transplantation
July / August 2006
Idiopathic pulmonary
fibrosis (IPF) is a chronic, progressive,
unrelenting fibrotic disorder of the lungs that ultimately
leads to respiratory failure and compromises both survival
and quality of life. Patients with IPF typically present
with clinical features such as shortness of breath, exercise
limitations and persistent nonproductive cough. On chest
X-ray, findings range from predominantly subpleural scarring
to diffuse fibrosis. These findings may be better appreciated
on a high-resolution CT chest scan.
On pathology, a usual
interstitial pneumonitis (UIP) pattern is typically seen
and characterized by minimal inflammation, the presence
of fibroblast foci, and extensive fibrosis or honeycombing
adjacent to relatively unaffected lung tissue. The pathogenesis
of IPF is unknown, but recent insights suggest that alveolar
epithelial injury and subsequent abnormal wound repair
with or without preceding chronic inflammation plays a central
role.
Prognosis for these patients is poor with some studies
reporting median survival to be less than three years. Most
patients do not respond to medical therapy and inevitably
progress to respiratory failure. Lung transplantation has
emerged as an important therapeutic option for select IPF
patients and offers the possibility of improving quality
of life and prolonging survival.
Until recently, lungs were allocated based on quantity
of time accrued on a lung transplant waiting list. Wait times
for some patients exceeded two years. This system placed
patients with very advanced disease or rapidly progressive
disease at a survival disadvantage since they were sometimes
unable to survive the lengthy wait times to transplant.
Since
May 2005, a new lung allocation system determines allocation
based on the severity of illness and likelihood of benefiting
from transplant. This new policy prioritizes patients with
advanced disease and significantly reduces wait times to
transplant. At Penn, the number of deaths on the waiting
list has declined dramatically since this new policy has
been implemented.
Improving Survival
Although lung transplantation
is an important therapeutic option for patients with IPF,
this procedure itself is associated with significant risks,
which include, but are not limited to, acute and chronic
rejection, infection, post-transplant malignancy, diabetes
mellitus and other immunosuppressive drug-specific side effects.
Outcomes
of patients transplanted at Penn have consistently met or
exceeded national statistics. Nevertheless, Penn surgeons,
physicians, nurse practitioners, physical therapists, respiratory
therapists, nutrition specialists, financial coordinators
and social workers continue their clinical work and research
to improve long-term outcomes. Currently, one-year survival
after transplantation is approximately 80 to 85 percent,
five-year survival about 50 percent and 10-year survival
about 25 percent.
“In IPF patients, it’s critical that you treat
any underlying co-morbidities,” says Vivek
Ahya, MD,
Medical Director of Penn’s Lung
Transplant Program. “For
example, a patient’s kidneys or heart may not be functioning
normally. We put together a multidisciplinary team specific
to the patient and we all work incredibly closely with the
surgeon to improve the patient’s health and, thus,
increase the chances of survival following transplantation.” That
team may also include infectious disease physicians, pharmacists,
cardiologists, and nephrologists.
Pre-operatively, IPF patients often receive pulmonary rehabilitation. “IPF
patients tend to be older and somewhat inactive. It’s
also likely that they have been treated with high-dose steroids
for a long time before requiring a transplant,” says
Dr. Ahya. The goal of rehabilitation is to improve their
strength and functional capacity in order to better prepare
them for the high-risk transplant surgery.
Outstanding Surgical Results
Lung transplantation
survival has improved significantly during the last 10 years. “The
procedure itself is relatively young but the advances have
been striking,” says
Alberto
Pochettino, MD, Surgical Director of Penn’s
Lung Transplantation Program. Improvements in surgical techniques,
changes to the management of donors and recipients and steady
advances in immunosuppressant regimens have contributed to
improved long-term survivals. Donor lung salvage techniques
have also improved, increasing the number of available donor
organs and their quality.
“The new allocation system has benefited a program
like Penn, where most of our patients present with advanced
lung disease and a more difficult to manage lung pathology,” says
Dr. Pochettino. “IPF has been and continues to be one
of the most common diagnoses at Penn requiring lung transplantation.
Last year, our program was the fourth largest lung transplantation
center in the country, with nearly 40 percent of the transplants
performed for IPF treatment.”
Reducing Risk of Rejection
Post-operatively, patients
are typically removed from a ventilator within 24 to 48 hours
following surgery and an epidural catheter is used to relieve
incisional pain. Within 24 hours after surgery, the patient
is re-taught how to cough and take a deep breath since the
new lung(s) do not have normal neural connections. Anti-rejection
medications are administered and immunosuppressant levels
are monitored daily.
“There have been a number of improvements in anti-rejection
medications, which can help to suppress the immune system
and stave off organ rejection,” says Dr. Ahya. “Nevertheless,
long-term survival for lung transplantation patients is often
shorter than heart or liver transplantation because the immunosuppressed
lung, unlike other organs, is exposed to the external environment
and thus particularly susceptible to various infectious and
other environmental pathogens.”
“The most important thing a physician can do is to
refer IPF patients early, since the disease progresses so
rapidly,” continues
Dr. Ahya. “Even if the patient is not in need of a
transplant, we can at least complete an evaluation and perform
the tests necessary to be put on the transplant list. That
way, when the patient is in need of transplantation, we can
activate him or her as soon as possible.”
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Referring Physicians: To speak with a Penn physician
or refer a patient, contact PennHealth through the secure online
referral form or by calling
1-800-789-PENN
(7366). |
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