CLINICAL INVESTIGATION BILIARY
Clinical Performance Status and Technical Factors Affecting
Outcomes from Percutaneous Transhepatic Biliary Interventions;
A Multicentre, Prospective, Observational Cohort Study
Gregory C. Makris1,2 • Andrew C. Macdonald3 • Kader Allouni4 •
Hannah Corrigall3 • Charles R. Tapping3 • Jane Philips Hughes3 • Suzie Anthony3 •
Phil Boardman3 • Rafiudin Patel3 • Andrew Wigham3 • Mohammad Ali Husainy3 •
Teik Choon See5 • James Cast6 • Simon Olliff7 • Simon Travis8 • Hans-Ulrich Laasch9 •
Colin Nice10 • Raman Uberoi3
Received: 20 December 2020 / Accepted: 28 May 2021 / Published online: 12 July 2021
 The Author(s) 2021
Abstract
Purpose The purpose of this study was to evaluate the
predictive value of a ‘Modified Karnofsky Scoring System’
on outcomes and provide real-world data regarding the UK
practice of biliary interventions.
Materials and Methods A prospective multi-centred cohort
study was performed. The pre-procedure modified
Karnofsky score, the incidence of sepsis, complications,
biochemical improvement and mortality were recorded out
to 30 days post procedure.
Results A total of 292 patients (248 with malignant
lesions) were suitable for inclusion in the study. The
overall 7 and 30 day mortality was 3.1% and 16.1%,
respectively. The 30 day sepsis rate was 10.3%. In the
modified Karnofsky ‘high risk’ group the 7 day mortality
was 9.7% versus 0% for the ‘low risk’ group (p = 0.002),
whereas the 30 day mortality was 28.8% versus 13.3%
(p = 0.003). The incidence of sepsis at 30 days was 19% in
the high risk group versus 3.3% at the low risk group
(p = 0.001)
Conclusion Percutaneous biliary interventions in the UK
are safe and effective. Scoring systems such as the
Karnofsky or the modified Karnofsky score hold promise in
allowing us to identify high risk groups that will need more
careful consideration and enhanced patient informed con-
sent but further research with larger studies is warranted in
order to identify their true impact on patient selection and
outcomes post biliary interventions.
Keywords Percutaneous  Biliary  Drainage 
Stenting
Introduction
Percutaneous Transhepatic Biliary Drainage (PTBD), with
or without stent insertion, is a valuable technique in the
management of biliary obstruction. External drainage or
internal drainage via a stent can relieve symptoms and
improve serum biochemistry. This can optimise the clinical
condition of patients requiring surgical resection or pal-
liative treatements, and improve their quality of life [1–3].
& Raman Uberoi
Raman.uberoi@ouh.nhs.uk
1 Vascular and Interventional Radiology Department, Guy’s
and St Thomas’ Hospital, NHS Foundation Trust, London,
UK
2 Alfa Institute of Biomedical Sciences, Neapoleos 9, Marousi,
Athens, Greece
3 Department of Interventional Radiology, Oxford University
Hospitals NHS Foundation Trust, oxford, UK
4 University Hospitals North Midlands NHS Foundation Trust,
Stoke-on-Trent, UK
5 Cambridge University Hospitals NHS Foundation Trust,
Cambridge, UK
6 Hull University Teaching Hospitals NHS Foundation Trust,
Hull, UK
7 University Hospitals Birmingham NHS Foundation Trust,
Birmingham, UK
8 Nottingham University Hospitals NHS Foundation Trust,
Nottingham, UK
9 The Christie NHS Foundation Trust, Manchester, UK
10 Newcastle Upon Tyne Hospitals NHS Foundation Trust,
Newcastle upon Tyne, UK
123
Cardiovasc Intervent Radiol (2021) 44:1625–1632
https://doi.org/10.1007/s00270-021-02888-0
PTBD is an invasive procedure and has associated
complications, including bleeding, infection and bile
leakage. The British Society of Interventional Radiology
Biliary Drainage and Stent Audit Report 2009 demon-
strated a 7.9% rate of major complications, a 26% rate of
minor complications and an in hospital mortality of 19.8%
[4]. The high associated mortality and complication rate
indicate a need to identify pre-procedural predictive factors
that will enable better patient selection.
The aim of this study was to evaluate a modified func-
tional scoring system (Modified Karnofsky score) in a
‘‘real-world data’’ setting, potentially allowing us to sup-
port measures to improve patient outcomes and advise
patients appropriately of their individual procedural risks.
Methods
Study Design and Objectives of the Study
This was a multicentre, prospective, observational cohort
study that ran over a four year period at eight UK sites. The
primary objective was to assess if the ‘Modified Karnofsky
Scoring System’ utilising performance status scores, co-
morbidities and biochemical/haematological markers could
gauge the risk of morbidity or mortality from PTBD. The
secondary objectives were to assess if the choice between
primary drain/stent placement and procedure staging may
also affect outcomes.
Study Population
The study prospectively recruited participants over
18 years of age, undergoing PTBD ± stenting for benign
or malignant causes.
Interventions
As this was an observational study it was at the treating
physicians’ discretion to perform stent or drain insertion
and also regarding staging of the procedures. The treat-
ments were not affected or dictated by the study protocol.
Study Assessments
The study was collecting data available in the patient notes
and on the electronic patient records and a standardised
proforma was completed prior to the procedure. The fol-
lowing were assessed at baseline: demographics; type of
stricture (benign/malignant obstruction) and site of
obstruction according to Bismuth classification [5]; current
treatments; previous medical history; performance status
(Karnofsky score); presence of ascites and biochemical/
haematological markers (bilirubin, albumin, haemoglobin,
platelets, clotting profile and white cell count).
The incidence of sepsis was assessed at 7 and 30 days.
Sepsis was defined by meeting the SIRS (systemic
inflammatory response) criteria in the presence of sus-
pected infection. The SIRS criteria required at least two of:
temperature[ 38 or\ 36 C, tachycardia[ 90 beats/
minute, serum white cell count[ 12 or\ 4 9 109/L. The
level of bilirubin and symptoms were assessed at 7 and
30 days and the responsible physician had to decide if the
symptoms were stable, worse or better. The same applied
to their bilirubin levels. If the investigators felt that the
change in the levels was clinically significant they were
asked to report it as such. No cut off values were provided.
All-cause mortality was recorded at 7 and 30 days.
Immediate post-operative complications were also docu-
mented (Table 1).
Table 1 Karnofsky Score Karnofsky Performance Status Score
Function Score (%)
Normal, no complaints, no signs of disease 100
Capable of normal activity, few symptoms or signs of disease 90
Normal activity with some difficulty, some symptoms or signs 80
Caring for self, not capable of normal activity or work 70
Requiring some help, can take care of most personal requirements 60
Requires help often, requires frequent medical care 50
Disabled, requires special care and help 40
Severely disabled, hospital admission indicated but no risk of death 30
Very ill, urgently requiring admission, requires supportive measures or treatment 20
Moribund, rapidly progressive fatal disease processes 10
Death 0
1626 G. C. Makris et al: Clinical Performance Status and Technical Factors Affecting Outcomes…
123
Pre-Procedural Scoring
By taking into account the success of previous studies
[4, 6–9] and utilising the predictive markers seen to most
strongly correlate with outcome, a novel scoring system
was produced (Table 2) (Appendix for CRF). The scoring
system developed is the ‘‘Modified Karnofsky’’ score
which had previously been piloted on 50 consecutive
patients. This is a combination of the Karnofsky perfor-
mance [10] score with biochemical markers including
albumin (g/l), prothrombin time (s) (INR), presence of
ascites, haemoglobin (g/dL), bilirubin (mmol/L) and white
cell count (9 109/L). Table 2 shows how different values
of the previously mentioned markers were assigned points,
the sum of which could be grouped into either a low risk
group (0–4 points) or a high risk group (C 5 points). The
classifications thresholds were extracted from the previous
pilot study and after consensus was achieved between the
members of the steering committee of the study (GM, AM,
RU).
Definition End of the Study
The end of study was 30 days following recruitment of the
last patient.
Ethics and Sponsoring
The study was approved by the Research and Development
committee of the Oxford University Hospitals NHS
Foundation Trust and the National Research and Ethics
Service.
The study was supported by an educational grant by the
British Society of Interventional Radiology.
Statistical Analysis
Post interventional complication rates, 7 and 30 day mor-
bidity and mortality as well as incidence of sepsis and
resolution of symptoms were correlated with pre-inter-
ventional factors such as co-morbidities; namely hyper-
tension (HTN), ischaemic heart disease (IHD), insulin
dependent diabetes mellitus (IDDM), presence of ascites,
disorders of coagulation and patients on anticoagulant
therapy. Outcomes were also measured against perfor-
mance scoring systems, namely the Karnofsky score, and
the ‘modified Karnofsky score’.
Data were analysed using SPSS (IBM). A p value
of\ 0.05 was interpreted to denote statistical significance
with a Chi-squared analysis performed to compare out-
comes of staged versus primary stenting, high versus low
risk groups and stent versus drain only groups. For com-
plications, Fisher’s exact test was applied to compare
values in the different groups. Receiver operator curves
were used to compare the Karnofsky with the modified
Karnofsky score. Binary regression analysis was performed
for categorical data to assess if any factors were specifi-
cally associated with the incidence of overall 30 day
mortality and incidence of sepsis 30 days post operatively.
Results
Demographics
From 308 identified patients, 292 were included in the
study. The excluded patients had either withdrawn from the
study or had endoscopic treatment instead. The mean age
was 72.3 (SD: 4.8) and 55.5% of patients were male. The
performance status of our cohort, (Karnofsky score)
was[ 80 in 134 out of 292 patients (45.9%), 60–79 in
112/292 (38.4%) and\ 60 in 44/292 (15.1%). Only 14%
Table 2 Proposed pre-
procedural risk for PTC
procedures
Modified Karnofski score
Outcomes: Points
Measure: 0 1 2
Albumin (g/l) [ 35 28–35 \ 28
Prothrombin Time (s) (INR) B 16 (\ 1.7) 17–20 (1.7–2.3) [ 20 ([ 2.3)
Ascites None Mild Moderate to severe
Haemoglobin (g/dL) C 11 \ 11—10 \ 10
Bilirubin (mmol/L) \ 100 100–300 [ 300
White Cell Count (9 109/L) \ 11 11—14 [ 14
Karnofsky Score* (%) C 80 60–79 [ 60
Total score:
Risk Group: Low Risk (0–4 points) High Risk (5 ? points)
G. C. Makris et al: Clinical Performance Status and Technical Factors Affecting Outcomes… 1627
123
of cases were treated with chemotherapy and 15.8% were
receiving anti-platelets. The following comorbidities were
present in our cohort: hypertension (28.8%), heart disease
(8.8%), diabetes (5.8%) and coagulopathy (9.2%).
Technical Information and Overall Outcomes
The majority of the cases (84.9% - 248/292) presented
with malignant obstruction and the remaining had benign
causes (biliary stones, post-operative strictures and pan-
creatitis complications were the most common). For the
malignant lesions the level of the obstruction according to
the Bismuth classification was as follows: type I 7/231
(3%), type II 40/231 (13.7%,) type IIIa-b 26/231 (8.9%),
type IVa-b 26/231 (8.9%) and distal type 132/231 (45.2%).
Biliary stents were used in 57.2% (171/292) of cases.
87.1% of these stents (149/171) were metal stents, 11 were
plastic and there was one biodegradable stent. The majority
of the stents were inserted as a one-stage procedure (120/
171–70.1%), whereas 51 out of 171 were performed as a
two-stage procedure. Most of the procedures were per-
formed with right sided access (154/205–75.1%) and only
5.4% with bilateral access (11/205). The vast majority of
the procedures took place under local anaesthetic and
conscious sedation (254/292–86%) and all had preopera-
tive antibiotics.
The technical success, defined as successful drainage,
was 95.2% (278/292) while symptoms at day 7 had
improved in 44.2% and in a further 34.2% of the patients at
day 30. The 30 day sepsis rate was 10.3% (30/292),
whereas 7 day and 30 day mortality in our cohort was
3.1% (9/292) and 16.1% (47/292), respectively. The levels
of bilirubin at day 7 had decreased in 74% (216/292) with
57% (167/292) remaining decreased after 30 days. Overall,
in the majority of cases (91%) there were no immediate
complications. The most common immediate complication
was post-operative pain (8.2%), followed by 2 cases of
stent dislodging and 3 cases of pancreatitis and one case of
haemorrhage that was not life-threatening. There was no
significant difference when comparing the above in the
malignant versus the non-malignant groups.
Subgroup analysis
Modified Karnofsky (Table 3).
In the modified Karnofsky high risk group (5 ?) the
7 day mortality was 9.7% versus 0% for the low risk group
(Pearson Chi square 9.6;df: 1; p = 0.002), whereas the
30 day mortality was 28.8% versus 13.3% (Pearson Chi
square 5.7;df:1; p\ 0.05). The incidence of sepsis at
30 days was 19% in the high risk group versus 3.3% at the
low risk group (Pearson Chi square 10.5; df:1; p = 0.001).
Bilirubin levels in day 7 decreased in 76.5% of the low risk
group and in 76.3% in the high risk group without a sta-
tistically significant difference (p = 0.8) and this trend was
continued at day 30 (65.1% vs.70.5%, p = 0.6). There was
no significant difference when comparing the above in the
malignant versus the non-malignant groups.
Standard Karnofsky Score
When we assessed sepsis and mortality using only the
Karnofsky score for risk stratification, there was also a
statistically significant difference in sepsis at day 30
(Pearson Chi-Square:15.897,df: 6; P = 0.014) and 30-day
mortality (Pearson Chi-Square;14.882,df 6;P = 0.021) with
higher mortality and sepsis rates in the group with Kar-
nofksy score of\ 60. When the two scores were compared
using ROC curves for the 30 day mortality the modified
Karnofsky score had an area under the curve of 0.580
(SE:0.47 with 95%CI:0.488–0.671) versus 0.607 (SE0.46
with 95%CI 0.518–0.696) for the Karnofsky score without
any statistically significant difference (Fig. 1). The same
trend was noted for 30 day sepsis with the modified
Karnofsky score having an area under the curve of 0.655
(SE:0.55 with 95%CI:0.548–0.763) versus 0.648 (SE0.59
with 95%CI 0.533–0.763) for the Karnofsky score without
any statistically significant difference (Fig. 2).
Primary Stenting vs Staged Procedure (Tables 4 and 5).
The incidence of sepsis at day 30 was higher at the
stented group, 11.7% versus 8.3% in the drain-only group
(p = 0.5), however this difference did not reach statistical
significance. Regarding mortality after 7 and 30 days in the
stented versus the drain-only group, again, there was a
trend for higher mortality in the stented group (Day 7:
Table 3 Outcomes in high vs
low risk modified Karnofsky
score
Modified Karnofsky,
High risk
Modified Karnofsky,
Low risk
P
7d Mortality (%) 9.7 0 0.002
30d Mortality (%) 28.8 13.3 0.003
30d Sepsis (%) 19 3.3 0.001
Bilirubin decreased at 7d(%) 76.3 76.5 0.8
Bilirubin decreased at 30d (%) 70.5 65.1 0.6
1628 G. C. Makris et al: Clinical Performance Status and Technical Factors Affecting Outcomes…
123
5.8% versus 1.6%, p = 0.1 and Day 30: 22.1% versus 18%,
p = 0.5) but without reaching statistical significance. The
30 day sepsis rate was 7.8% for the group that had stenting
as a two stage procedure versus 11.7% for the single stage
stenting group, however the difference was not statistically
significant (Pearson 6.027, df:4; p = 0.197).
Fig. 1 30 day mortality ROC
curves between the two
performance scores
Fig. 2 7 day sepsis ROC curves
between the two performance
scores
Table 4 Outcomes in stented vs drain only subgroups
Stented Drain only P
7d Mortality (%) 5.8 1.6 0.1
30d Mortality (%) 22.1 18 0.5
30d Sepsis (%) 11.7 8.3 0.5
Bilirubin decreased at 7d (%) 79.3 72.7 0.46
Bilirubin decreased at 30d (%) 69.7 62.1 0.3
Table 5 Outcomes following one or two stage stent procedures
Two stage stent One stage stent P
30d Mortality (%) 15 19.2 0.194
30d Sepsis (%) 7.8 11.7 0.197
G. C. Makris et al: Clinical Performance Status and Technical Factors Affecting Outcomes… 1629
123
In the subgroup analysis using the modified Karnofsky
score, the incidence of sepsis between the high and low risk
groups in the drain only cases was not statistically signif-
icant (15.4% versus 7.5%, p = 0.444), but this difference
was significant in the stented group. More specifically, the
30 day sepsis, in the drain-only patients was 13% for high
risk versus 5.4% for low risk, p = 0.2 , while in the stent
group it was 23.1% for high risk versus 1.9% for low risk,
p = 0.001. The 7 and 30 day mortality for the stent versus
drain-only patients was 13.3% versus 3.8%, p = 0.19 and
27.5% versus 32%, p = 0.69, respectively.
In the binary regression model the high risk group
according to modified Karnofsky score (p = 0.035), the
type of stricture (p = 0.019) and the level of bilirubin
postoperatively (P = 0.004) appeared to be significantly
associated with the incidence of overall mortality at
30 days (P = 0.035). Regarding the incidence of sepsis at
30 days, female gender (P = 0.046), use of antiplatelets
(p = 0.017) and the being at the high risk group of the
modified Karnofsky score (p = 0.015) were the only fac-
tors that appeared to be significantly associated with
increased risk of sepsis. When the binary regression model
was adjusted to assess only the malignant lesions in the
cohort, the high risk group according to the modified
Karnofksy score remained a significant factor (p\ 0.05)
along with level or postoperative bilirubin (p\ 0.05).
Discussion
This is the first study to our knowledge to prospectively
assess a scoring system in predicting the outcomes of bil-
iary drainage and stenting procedures. Patients undergoing
biliary procedures are generally unwell and our study
supports the notion that the patient’s clinical status is a key
determinant in affecting mortality and morbidity post
PTBD. Indeed our study showed that high risk patients in
the modified Karnofsky score show worse outcomes when
it comes to mortality and sepsis incidence. In addition,
although the choice between stent or drain insertion did not
seem to affect mortality and morbidity, a difference was
found on subgroup analysis of the Modified Karnofsky
high-risk group versus the low risk groups, with high risk
patients who received stents appearing to have worse out-
comes than those who were in the low risk groups. The fact
that patients in the high risk clinical group appear to be
doing worse when receiving biliary stents than those
receiving drains only may be related to increased proce-
dural time and increased risk of bacteraemia which in
combination with the poor performance status could
explain the poor outcomes. However, despite these
important findings, both the Karnofsky and modified
Karnofsky scores, did not show high differentiation ROC
curves for mortality and morbidity and were not shown to
be significantly different from each other which might be a
result of the relatively small sample size.
We had previously carried out a small local pilot study
in 50 consecutive patients and based on the positive finding
in this cohort wanted to test the modified Karnovsky
scoring system in a larger cohort in a multi-centre setting.
The modified Karnofksy score incorporates a number of
significant biochemical factors to the pre-existing clinical
score which have previously been shown to independently
correlate with worse outcomes and therefore cannot be
disregarded without further research. When assessing the
technical factors that might be affecting mortality and
morbidity, it was noted that in the stent only group there
was a trend for higher incidence of sepsis at 30 days and
higher 30 day mortality, however this was not statistically
significant. When assessing one versus two-stage stenting
affects mortality and morbidity, the trend for sepsis and
30 day mortality were lower in the group that had a two-
stage procedure, however, these results also did not reach
statistical significance. Furthermore, our study showed no
statistically significant difference in mortality or morbidity
when comparing patients who received stent versus those
who only had a drain. Regarding the issue of performing
the procedure in one or two-stages, there is limited evi-
dence from previous studies which suggests a two-stage
procedure does not have any clear benefits on mortality and
morbidity but associated with increased the cost and pro-
cedure time. [11–14]. It does seems however that centre
experience may also be an important factor and those
centres that performs more than 28 procedures per year
have a significantly lower mortality [15].
This is the largest prospective study in the United
Kingdome and confirms that PTC is a technically feasible
and effective procedure (95% technical success rate) with
similar mortality and morbidity rates as reported elsewhere
in the literature [16]. Despite the majority of our study
participants having a relatively good performance status,
the incidence of 30-day sepsis was 10% and the overall
30 day mortality was 16%. These results reaffirm the
findings of other large series [4, 15].
This study has limitations that should be taken into
account. Data quality and completeness are often signifi-
cant concern, since it represents a prospective, voluntary
data collection effort from various centres and physicians
across the UK and could be a non-consecutive patient
cohort unrepresentative of the entire treated population.
We did however ensure optimal data collection in this
study with follow up contacts with all centres to achieve
data completeness. Another potential limitation comes
from the fact that participating clinician was given the
freedom to select patients on local criteria and to treat them
using their local protocols, which increased the
1630 G. C. Makris et al: Clinical Performance Status and Technical Factors Affecting Outcomes…
123
heterogeneity of observed treatment and follow-up prac-
tices. However this did allow us to ensure that we were
testing the scoring systems in a real-world scenario.
Conclusion
PTB plays a key role in managing patients with biliary
obstructions who are often severely debilitated and at high
risk. However technical success rates remain excellent with
a good safety profile. Scoring systems such as the
Karnofsky or the modified Karnofsky score potentially
allow us to identify high risk groups that will need more
careful consideration, risk factor modification and
enhanced patient informed consent. Further research with
larger studies is warranted in order to identify their true
impact on patient selection and outcomes post biliary
interventions.
Acknowledgements We would like to thank the following for their
contributions to patient care, recruitment or administrative assistance:
Drs Damian Mullan, Pavan Najran and John K Bell, The Christie
NHS Foundation Trust. Drs David Wells, Christopher Day, Biju
Thomas and Mona Mossad, University Hospitals North Midlands
NHS Trust. Drs Oliver Byass and Lynn Ling, Hull University
Teaching Hospitals NHS Trust. Drs Ralph Jackson, Peter Littler, Rob
Williams, Phil Haslam, The Newcastleupon Tyne Hospitals NHS
Foundation Trust. Dr Homoyon Mehrzad and Karen Isaacs, Queen
Elizabeth Hospital, Birmingham.
Funding This study was funded by the British Society of Interven-
tional Radiology.
Declaration
Conflicts of interest The authors declare that they have no conflict of
interest.
Ethical Approval Institutional Review Board approval was granted
for this study.Human or Animal RightsAll procedures performed in
studies involving human participants were in accordance with the
ethical standards of the institutional and/or national research com-
mittee and with the 1964 Helsinki Declaration and its later amend-
ments or comparable ethical standards.
Informed Consent Informed consent was obtained from all indi-
vidual participants included in the study.For all research involving
human subjects, informed consent to participate in the study should be
obtained from participants (or their parent or legal guardian in the
case of children under 16).
Consent for Publication Consent for publication was obtained for
every individual person’s data included in the study.
Open Access This article is licensed under a Creative Commons
Attribution 4.0 International License, which permits use, sharing,
adaptation, distribution and reproduction in any medium or format, as
long as you give appropriate credit to the original author(s) and the
source, provide a link to the Creative Commons licence, and indicate
if changes were made. The images or other third party material in this
article are included in the article’s Creative Commons licence, unless
indicated otherwise in a credit line to the material. If material is not
included in the article’s Creative Commons licence and your intended
use is not permitted by statutory regulation or exceeds the permitted
use, you will need to obtain permission directly from the copyright
holder. To view a copy of this licence, visit http://creativecommons.
org/licenses/by/4.0/.
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