IN RE: Bard Implanted Port Catheter Products Liability Litigation

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WO
IN THE UNITED STATES DISTRICT COURT
FOR THE DISTRICT OF ARIZONA
IN RE: Bard Implanted Port Catheter
Products Liability Litigation MDL No. 3081
ORDER
Dr. Ronald Thisted
This multidistrict litigation (“MDL”) involves thousands of personal injury cases
related to implanted port catheters (“IPCs” or “ports”) designed, manufactured, and
marketed by Defendants Becton Dickenson and Company, C. R. Bard, Inc., Bard Access
Systems, Inc., and Bard Peripheral Vascular, Inc. (collectively, “Defendants” or “Bard”).
Plaintiffs have filed a motion to exclude the expert opinions of Ronald Thisted, Ph.D.
Doc. 4831. The motion is fully briefed and no party requests oral argument. See
Docs. 5327, 5579. The Court will deny the motion.
I. Background.
An IPC is a medical device surgically implanted under the skin to provide repeated
access to a patient’s vascular system without the need for multiple needlesticks into
peripheral veins. IPCs are used to deliver chemotherapy and immunotherapy medication,
intravenous fluids, blood transfusions, and parenteral nutrition. IPCs can remain in place
for weeks, months, or even years until treatment is completed.
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IPCs consist of a port and a catheter. The port is a small reservoir disc with a self-
sealing silicone center where a needle can be inserted to deliver medication. The port
typically is implanted beneath the chest skin and below the collarbone. Port bodies vary
in shape and size and are made of plastic, silicone, or titanium. The port is attached to a
catheter, which is a thin flexible tube for delivery of the medication to a vein. The catheter
is tunneled under the skin to an insertion point in a central vein. Catheters vary in width
and are made of silicone or polyurethane. IPCs typically are implanted by an interventional
radiologist or a vascular surgeon. A nurse or other medical professional then accesses the
IPC to inject the medication, which flows from the port to the catheter and into the vein.
This MDL involves multiple versions of Bard IPCs, each of which received
premarket clearance from the Food and Drug Administration (“FDA”). Bard IPCs contain
barium sulfate, a radiopaque substance that can be seen on diagnostic imaging such as
X-ray, CT, and MRI scans. Several Bard IPCs are manufactured using polyoxymethylene
(“POM”), an acetal thermoplastic polymer, in the construction of the port. Many Bard
IPCs have a port with raised palpation bumps on the silicone center, which help identify
these IPCs as power-injectable devices.
Each Plaintiff in this MDL had a Bard IPC implanted in his or her body, and claims
it was defective and caused serious injury. Plaintiffs allege that the barium sulfate in the
IPC degrades the mechanical integrity of the catheter, leading to surface irregularities that
cause catheter fracture, infection, and blood clots. Plaintiffs further allege that Bard’s
manufacturing process for the POM-containing IPCs lacks adequate measures to stabilize
the POM to prevent oxidative degradation, which causes cracks, fissures, and other
physical defects in the polymer and increases the risk of fracture, infection, and thrombosis.
Plaintiffs also allege that the palpation bumps on the power-injectable IPCs cause undue
compression stress on the tissue surrounding the port, leading to ulceration and tissue
necrosis. See Docs. 23, 1889.
Plaintiffs claim that safer alternative designs and manufacturing processes were
available to Bard and that Bard IPCs are more dangerous than other available treatment
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options. Plaintiffs assert a host of state law claims, including design and manufacturing
defects, failure to warn, breach of warranty, misrepresentation, concealment, and consumer
fraud and unfair trade practices. See Docs. 23, 1889.
Bard disputes Plaintiffs’ allegations and contends its IPCs are safe and effective and
that the medical community is aware of risks associated with IPCs. Bard further contends
that various factors impact the performance and wear of IPCs, including where the catheter
is inserted and how well the device is maintained by medical professionals and the patient.
See Docs. 23, 2023-1.
The parties plan to use various expert witnesses at trial, including biostatisticians
and epidemiologists. Defendants have identified Dr. Thisted as an expert in biostatistics,
epidemiology, clinical research methods, and evidence-based medicine. See Doc. 5327 at
2, 3-5. Defendants tasked Thisted with evaluating the relevance and quality of scientific
literature regarding adverse event rates for IPCs and other venous access devices,
determining whether IPC-related adverse events were widely known in the medical
community, and examining the strengths and limitations of opinions of Plaintiffs’ experts
and the literature on which they rely. Docs. 5327 at 2, 4381-1 ¶¶ 1-2, 22-25.
Thisted has prepared a 103-page report which provides his expert qualifications
(Doc. 4831-1 ¶¶ 6-19); a background on evidence-based medicine, including the hierarchy
of evidence, study design principals, and statistical and epidemiological concepts (id.
¶¶ 51-86); an evidence-based review of the scientific literature, including human and
animal studies, studies with no original clinical data, and laboratory test results (id.
¶¶ 87-215); and rebuttals to certain opinions of Plaintiffs’ expert Dr. Becky Smith, an
epidemiologist and infection disease specialist, and Drs. Bernard Camins and William
Jarvis, infectious disease specialists (id. ¶¶ 216-300). Thisted opines that (1) the risks of
catheter-related bloodstream infections (“CRBSI”), thrombosis, and fractures involving
IPCs have been well-documented in the scientific literature for the last 25 years (id. ¶ 36);
(2) he would expect healthcare professionals who prescribe, implant, or maintain IPCs to
be familiar with these risks and to consider them in making treatment choices (id. ¶ 37);
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(3) there is no Level I or Level II evidence showing that Bard IPCs are associated with a
higher rate of CRBSI, thrombosis, or fracture than the rates of these complications for other
implanted port systems (id. ¶¶ 38-40); (4) complication rates for peripherally inserted
central catheters and central lines are generally higher than for IPCs (id. ¶ 41-42); (5) there
is no peer-reviewed literature or other good evidence showing that catheters with
antimicrobial coatings reduce the risk of CRBSI in long-term applications (id. ¶¶ 43, 45);
(6) there is no published literature showing that IPCs with antithrombotic materials reduce
the rate of thrombosis (id. ¶ 44); (7) no medical organization or governmental agency
recommends the use of antimicrobial-coated catheters over standard catheters for use
exceeding one month (id. ¶ 46); (8) laboratory and animal testing cannot be relied on to
show that the effects seen in such testing would occur in IPCs in clinical practice or would
occur to the same degree (id. ¶¶ 47-48); and (9) Drs. Smith, Camins, and Jarvis draw
inferences about potential clinical outcomes from laboratory and animal studies despite
explicit warnings in the studies against making such inferential leaps (id. ¶ 49). Plaintiffs
move to exclude Thisted’s opinions under Federal Rule of Evidence 702. Doc. 4831.
II. Legal Standard.
Rule 702 provides that “[a] witness who is qualified as an expert by knowledge,
skill, experience, training, or education may testify in the form of an opinion” if the
proponent of the expert’s testimony “demonstrates to the court that it is more likely than
not that” (a) “the expert’s scientific, technical, or other specialized knowledge will help the
trier of fact to understand the evidence or to determine a fact in issue,” (b) “the testimony
is based on sufficient facts or data,” (c) “the testimony is the product of reliable principles
and methods,” and (d) “the expert’s opinion reflects a reliable application of the principles
and methods to the facts of the case.” Fed. R. Evid. 702(a)-(d). The proponent must show
by a preponderance of the evidence that the testimony satisfies each of these requirements.
Fed. R. Evid. 104(a); Fed. R. Evid. 702 advisory committee’s note to 2023 amendment
(“[T]he rule has been amended to clarify and emphasize that expert testimony may not be
admitted unless the proponent demonstrates to the court that it is more likely than not that
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the proffered testimony meets the admissibility requirements set forth in the rule.”); Engilis
v. Monsanto Co., 151 F.4th 1040, 1050 (9th Cir. 2025) (“Consistent with the 2023
amendment, our precedent establishes that Rule 702 requires a proponent of expert
testimony to demonstrate each of the requirements of Rule 702 by a preponderance of the
evidence.”).
The Court acts as a gatekeeper to ensure that expert testimony satisfies Rule 702.
Daubert v. Merrell Dow Pharms., Inc., 509 U.S. 579, 597 (1993). The Court’s task is not
to decide whether the expert is right or wrong, but to ensure the proposed opinions satisfy
Rule 702. Alaska Rent-A-Car, Inc. v. Avis Budget Grp., 738 F.3d 960, 969-70 (9th Cir.
2013); Engilis, 151 F.4th at 1050. If the proponent does not meet its Rule 702 burden, the
expert testimony is not admissible. See Davis v. McKesson Corp., No. CV-18-1157-PHX-
DGC, 2019 WL 3532179, at *3 n.2 (D. Ariz. Aug. 2, 2019) (“[T]he Court may admit expert
opinions only if it can determine, under Rule 104(a), that Plaintiffs have shown each of the
Rule 702 requirements to be satisfied by a preponderance of the evidence.”).
III. Discussion.
Plaintiffs argue that Thisted is not qualified to critique or offer medical opinions
(Doc. 4831 at 3-9), his opinions regarding what the scientific evidence shows about
causation are not reliable (id. at 9-14), and his opinions are not relevant or helpful to the
jury (id. at 14-15). Thisted’s qualifications will be addressed in part A below, and the
reliability and relevance of his opinions in parts B and C.
A. Thisted’s Qualifications.
Thisted has more than fifty years of experience in biostatistics and epidemiology.
Doc. 4831-1 ¶ 6. He earned a Ph.D. in statistics from Stanford University in 1977. Id. ¶ 8.
He served on the faculty of the University of Chicago for more than 40 years, ultimately
as Professor Emeritus of Statistics and Public Health Sciences. Id. ¶¶ 7, 9. He taught
courses on statistics, computation, epidemiology, and clinical research methods, and served
as Co-Director of the Clinical Research Training Program and Chair of the Department of
Health Studies. Id. ¶¶ 9, 12. He is a Fellow of the American Statistical Association and
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the American Association for the Advancement of Science. Id. ¶ 14. He has authored
more than 100 peer-reviewed publications in leading medical journals, written dozens of
chapters, comments, and reviews in other publications, and reviewed grant proposals for
the National Institutes of Health and the National Science Foundation. Id. at ¶¶ 15-16.
Since the 1970s, Thisted has collaborated with healthcare professionals in designing and
interpreting clinical studies, and has consulted for the pharmaceutical and medical device
industries on the design of clinical trials and statistical analysis of the results. Id. ¶¶ 17-18;
see also id. at 107-22 (Thisted’s CV).
Plaintiffs argue Thisted is not qualified to critique or offer “medical opinions”
because he is not a medical doctor, engineer, or materials scientist, and has no expertise in
infectious diseases, hematology, or interventional radiology. Doc. 4831 at 2, 4-6. Plaintiffs
assert that Thisted “catalogues the scientific literature cited by Drs. Smith, Camins, and
Jarvis . . . and then opines as to why the literature cannot support a medical opinion.” Id.
at 6. Plaintiffs cite various paragraphs of Thisted’s report in which he discusses literature
on vitro studies, in vivo animal models, laboratory test results, and practice guidelines, but
do not identify the purported “medical opinions” they claim are impermissible. Id. (citing
Doc. 4831-1 ¶¶ 189-215, 300)).1
Defendants explain that the opinions of Plaintiffs’ experts that Thisted critiques are
literature-based causation opinions, not medical opinions, and that even a cursory review
of Thisted’s report shows that he offers no medical opinion and instead focuses on the
literature Plaintiffs’ experts cite and the studies he found through his own research.
Doc. 5327 at 2, 7. Defendants argue that Thisted is eminently qualified to opine on the
quality and relevance of scientific literature and the strengths and limitations of the
literature-based causation opinions of Plaintiffs’ experts. Id. at 3-5, 7-8. Defendants
further argue that Rule 702 does not require a medical degree for statistical or
1 Nor do Plaintiffs address the opinions Thisted provides in the “summary of
opinions” section of his report. See Doc. 4831-1 ¶¶ 36-50.
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epidemiological critiques. Id. at 7. Plaintiffs do not address these arguments in their reply.
See Doc. 5579 at 2-3.2
The Court concludes that Thisted’s extensive experience in biostatistics,
epidemiology, clinical research methods, and evidence-based medicine (see Doc. 4831-1
¶¶ 6-19) qualifies him to opine on the quality and relevance of scientific literature and the
strengths and limitations of the literature-based causation opinions of Plaintiffs’ experts.
Plaintiffs concede that as a biostatistician, Thisted may evaluate whether statistical
evidence of an association exists, whether studies are adequately powered, randomized,
and controlled, and whether reported confidence intervals support an author’s conclusions.
Doc. 4831-1 at 6. Defendants make clear that this is precisely what Thisted has done in
this case and that he disclaims opinions outside his expertise. Doc. 5327 at 8. Plaintiffs
may object at trial if they believe Thisted attempts to offer impermissible medical
opinions.3
Plaintiffs argue that Thisted has no training or experience related to the medical and
clinical issues in this case. Doc. 4831 at 6-7. But he is or has been a professor at the
University of Chiago in public health sciences, biostatistics, clinical research and training,
clinical pharmacology and pharmacogenomics, anesthesia, and critical care. Doc. 4831-1
at 108. For 15 years he taught a required first-year course in Chicago’s Pritzker School of
Medicine on epidemiology and clinical investigation that focused on evidence-based
medicine, clinical evidence, critical appraisal of medical literature, and the relative merits
2 Plaintiffs argue in their reply that the following opinion in the introduction section
of Thisted’s report does not concern any research study: “As explained below, I disagree
with the opinions of both Dr. Smith and Drs. Camins and Jarvis that Defendants’ port
catheters cause bloodstream infections, thromboses, or fractures at a rate higher than
alternative totally implanted port catheters.” Id. at 7-8 (citing Doc. 4831-3 ¶ 3). Plaintiffs
do not address Thisted’s explanation for this opinion, which focuses primarily on the
medical literature relied on by Smith, Camins, and Jarvis (see, e.g., Doc. 4831-1 at 67-101),
nor did they challenge this opinion in their motion. See Doc. 4831 at 3-9. The Court will
not consider an argument made for the first time in a reply brief. See United States v.
Anderson, 472 F.3d 662, 668 (9th Cir. 2006).
3 Plaintiffs argue that Thisted misinterpreted epidemiological studies because he
admitted at his deposition that he did not understand the meaning of the term “evulsion” or
that “MPC” refers to “zwitterionic coating.” Doc. 4831 at 5. Plaintiffs will be free to
cross-examine Thisted on this issue, but it does not render him unqualified. See Doc. 5327
at 8-9.
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and drawbacks of the most common study designs in medical literature. Id. at 7. He is a
member of the International Biometric Society (id. at 108) and has published works in
medical and clinical journals (id. at 109-10) and on in vitro studies, medical sciences, and
medical decision making (id. at 110, 113, 115), and has taught courses in clinical research
methods (id. at 119-20).
Plaintiffs provide a 17-item bullet-point list of topics they claim would be “equally
problematic” for Thisted to opine on because his purported opinions on these topics are not
grounded in statistics or epidemiology. Doc. 4831 at 7-8. Plaintiffs provide string cites to
paragraphs of Thisted’s report, but they do not address his rationale in those paragraphs or
the scientific literature he addresses. Id. Nor do Plaintiffs address Defendants’ argument
that the paragraphs and their underlying citations show Thisted is rebutting the opinions of
Plaintiffs’ experts based on scientific literature. Docs. 5327 at 9, 5579 at 2-3. Plaintiff’s
argument is unpersuasive.
The Court finds by a preponderance of the evidence that Thisted is qualified under
Rule 702 to provide the opinions in his report.
B. Reliability of Thisted’s Opinions.
Plaintiffs challenge Thisted’s opinions that there is no evidence in the scientific
literature showing that Bard IPCs are associated with a higher rate of CRBSI, thrombosis,
or fracture than the rates of these complications for other implanted port systems.
Doc. 4831 at 9 (citing Doc. 4831-1 ¶¶ 38-40, 102-03, 297-301; Doc. 4832-2 at 21-22).
Plaintiffs argue that Thisted used no recognized epidemiological method in reaching these
opinions. Id. at 9-10.
Thisted explains his methodology. He assessed relevant scientific literature using
established principles of evidence-based medicine review, including hierarchy of evidence
principles; concepts of statistics, such as statistical testing and statistical significance; and
fundamental aspects of clinical and epidemiologic study design, such as the distinction
between prospective and retrospective clinical studies, randomized clinical trials, and the
importance of controls to eliminate bias. Doc. 4831-1 ¶¶ 31, 51. Because the devices at
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issue are implantable port catheters typically used for long-term central venous access,
Thisted gave more weight to clinical evidence from studies involving implantable ports
than to other methods of central venous access, and gave less weight to clinical evidence
from short- or medium-term studies than to longer-term investigations. Id. ¶ 32. Similarly,
he gave greater weight to clinical reports of adverse event rates that take length of exposure
into account, less weight to anecdotal accounts that provide no comparative data, and more
weight to rigorously designed and executed studies comparing outcomes under different
conditions. Id. He also gave less weight to laboratory studies and animal models than to
studies of clinical outcomes in actual patients. Id.; see also Doc. 5327 at 5-6.
Thisted states that the methods he employed are the same methods he has taught at
the University of Chicago and the Pritzker School of Medicine in statistics, epidemiology,
public health, and medicine. Doc. 4831-1 ¶ 28. As already noted, one of the courses he
taught focused on evidence-based medicine, including assessment of clinical evidence,
critical appraisal of the medical literature, and the relative merits and drawbacks of study
designs commonly seen in the medical literature. Id. Thisted states that his opinions are
also based on his training, experience, and practice as a biostatistician, epidemiologist, and
clinical research scientist over the last 50 years. Id.
Plaintiffs assert that hierarchy of evidence is “no methodology at all” because it is
“simply a descriptive classification system that ranks the strength and reliability of
different clinical study designs.” Doc. 4831 at 10. But hierarchy of evidence is only one
of several tools Thisted used in performing his evidence-based review of the literature. See
Doc. 4831-1 ¶¶ 31, 51, 87-215. Plaintiffs cite no authority suggesting that applying
hierarchy of evidence principles as part of an evidence-based review of scientific literature
is unreliable. To the contrary, Plaintiffs’ epidemiology expert, Dr. Smith, agreed that
hierarchy of evidence is taught in medical school and Thisted is “100 percent correct as to
where the studies rank on hierarchy of evidence.” Doc. 5327-1 at 3-4; see Doc. 5327 at 10.
Plaintiffs assert that Thisted’s “only abstract imperative” is set forth in paragraph
32 of his report, in which he explains why he gave more or less weight to certain types of
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studies. Doc. 4831 at 11. Plaintiffs argue that in the areas of Thisted’s expertise – statistics
and epidemiology – “scientific reliability requires more than reviewing studies one by one
and discarding those he disfavors.” Id. at 9. But Plaintiffs omit Thisted’s comprehensive
discussion in paragraphs 51 through 86 on the background and application of “statistical
testing and statistical significance, and on fundamental aspects of clinical and
epidemiologic study design.” Doc. 4831-1 ¶ 51. Plaintiffs also omit that Thisted evaluates
the literature cited by Plaintiffs’ experts “arranged according to the level and strength for
addressing the specific questions [they] considered, . . . specifically concerning rates of
complications attributable to Bard central venous ports.” Id. ¶ 93; see Doc. 5327 at 13.
Plaintiffs argue that Thisted’s methodology is unreliable because he did not apply
the Bradford Hill criteria. Doc. 4831 at 11-14. These criteria are used by epidemiologists
to establish a causal link. In re Zoloft Prods. Liab. Litig., 858 F.3d 787, 795 (3rd Cir. 2017)
(“The Bradford Hill criteria are metrics that epidemiologists use to distinguish a causal
connection from a mere association.”). The criteria “‘start with an association
demonstrated by epidemiology and then apply’ eight or nine criteria to determine whether
that association is causal.” In re Mirena IUS Levonorgestrel-Related Prods. Liab. Litig.
(No. II), 341 F. Supp. 3d 213, 242 (S.D.N.Y. 2018) (quoting In re Breast Implant Litig., 11
F. Supp. 2d 1217, 1234 (D. Colo. 1998)).
Plaintiffs, who have the burden of proving causation in this case, do not claim that
their own experts used the Bradford Hill criteria. Nor do they explain why Defendants,
who do not have the burden of proving of disproving causation, are required to use the
criteria. It would be one thing for Plaintiffs to argue that their experts used Bradford Hill
and Thisted failed to address it. Plaintiffs do not make this argument. They instead contend
that Thisted was required to use Bradford Hill to criticize the evidence Plaintiffs rely on to
show causation. The Court finds Plaintiffs’ argument wholly unpersuasive. Defendants
are entitled to discredit the evidence Plaintiffs present to prove their case, and Thisted’s
opinion will be relevant and helpful to the jury in evaluating the studies and medical articles
on which Plaintiffs rely to prove causation.
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The Court finds by a preponderance of the evidence that Thisted uses a sufficiently
reliable methodology under Rule 702. See Doc. 5327 at 5-6, 13-16.
C. Relevance of Thisted’s Opinions.
Plaintiffs argue Thisted’s opinions will not help the jury because he does not say
whether Bard’s IPCs “are safer or less safe” than alternative designs or whether anti-
microbial and non-fouling surfaces are unsafe or ineffective in reducing catheter-related
complications. Doc. 4831 at 14. But Plaintiffs, not Defendants, bear the burden of proof
on these issues. Defense counsel, not Plaintiffs’ counsel, get to determine the scope of
Thisted’s opinions. His opinions directly address a significant part of Plaintiffs’ claim –
that scientific literature and other evidence on adverse-event rates show Defendants’ IPCs
are more dangerous than other alternatives and cause the injuries at issue in this litigation.
The jury will be required to evaluate Plaintiffs’ evidence, and Thisted’s opinions will be
helpful in that evaluation if the jury decides to believe them.
IT IS ORDERED that Plaintiffs’ motion to exclude opinions of Ronald Thisted,
Ph.D. (Doc. 4831) is denied.
Dated this 14th day of April, 2026.
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